/libpcap/pcap-linux.c
C | 6603 lines | 3429 code | 559 blank | 2615 comment | 832 complexity | 03a345b611892f4e8203020796700711 MD5 | raw file
Possible License(s): BSD-3-Clause, GPL-2.0, Apache-2.0, LGPL-2.0, LGPL-2.1, MIT
- /*
- * pcap-linux.c: Packet capture interface to the Linux kernel
- *
- * Copyright (c) 2000 Torsten Landschoff <torsten@debian.org>
- * Sebastian Krahmer <krahmer@cs.uni-potsdam.de>
- *
- * License: BSD
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- * 3. The names of the authors may not be used to endorse or promote
- * products derived from this software without specific prior
- * written permission.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- *
- * Modifications: Added PACKET_MMAP support
- * Paolo Abeni <paolo.abeni@email.it>
- * Added TPACKET_V3 support
- * Gabor Tatarka <gabor.tatarka@ericsson.com>
- *
- * based on previous works of:
- * Simon Patarin <patarin@cs.unibo.it>
- * Phil Wood <cpw@lanl.gov>
- *
- * Monitor-mode support for mac80211 includes code taken from the iw
- * command; the copyright notice for that code is
- *
- * Copyright (c) 2007, 2008 Johannes Berg
- * Copyright (c) 2007 Andy Lutomirski
- * Copyright (c) 2007 Mike Kershaw
- * Copyright (c) 2008 Gรกbor Stefanik
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. The name of the author may not be used to endorse or promote products
- * derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- /*
- * Known problems with 2.0[.x] kernels:
- *
- * - The loopback device gives every packet twice; on 2.2[.x] kernels,
- * if we use PF_PACKET, we can filter out the transmitted version
- * of the packet by using data in the "sockaddr_ll" returned by
- * "recvfrom()", but, on 2.0[.x] kernels, we have to use
- * PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a
- * "sockaddr_pkt" which doesn't give us enough information to let
- * us do that.
- *
- * - We have to set the interface's IFF_PROMISC flag ourselves, if
- * we're to run in promiscuous mode, which means we have to turn
- * it off ourselves when we're done; the kernel doesn't keep track
- * of how many sockets are listening promiscuously, which means
- * it won't get turned off automatically when no sockets are
- * listening promiscuously. We catch "pcap_close()" and, for
- * interfaces we put into promiscuous mode, take them out of
- * promiscuous mode - which isn't necessarily the right thing to
- * do, if another socket also requested promiscuous mode between
- * the time when we opened the socket and the time when we close
- * the socket.
- *
- * - MSG_TRUNC isn't supported, so you can't specify that "recvfrom()"
- * return the amount of data that you could have read, rather than
- * the amount that was returned, so we can't just allocate a buffer
- * whose size is the snapshot length and pass the snapshot length
- * as the byte count, and also pass MSG_TRUNC, so that the return
- * value tells us how long the packet was on the wire.
- *
- * This means that, if we want to get the actual size of the packet,
- * so we can return it in the "len" field of the packet header,
- * we have to read the entire packet, not just the part that fits
- * within the snapshot length, and thus waste CPU time copying data
- * from the kernel that our caller won't see.
- *
- * We have to get the actual size, and supply it in "len", because
- * otherwise, the IP dissector in tcpdump, for example, will complain
- * about "truncated-ip", as the packet will appear to have been
- * shorter, on the wire, than the IP header said it should have been.
- */
- #define _GNU_SOURCE
- #ifdef HAVE_CONFIG_H
- #include "config.h"
- #endif
- #include <errno.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <ctype.h>
- #include <unistd.h>
- #include <fcntl.h>
- #include <string.h>
- #include <limits.h>
- #include <sys/stat.h>
- #include <sys/socket.h>
- #include <sys/ioctl.h>
- #include <sys/utsname.h>
- #include <sys/mman.h>
- #include <linux/if.h>
- #include <linux/if_packet.h>
- #include <linux/sockios.h>
- #include <netinet/in.h>
- #include <linux/if_ether.h>
- #include <net/if_arp.h>
- #include <poll.h>
- #include <dirent.h>
- #include "pcap-int.h"
- #include "pcap/sll.h"
- #include "pcap/vlan.h"
- /*
- * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
- * sockets rather than SOCK_PACKET sockets.
- *
- * To use them, we include <linux/if_packet.h> rather than
- * <netpacket/packet.h>; we do so because
- *
- * some Linux distributions (e.g., Slackware 4.0) have 2.2 or
- * later kernels and libc5, and don't provide a <netpacket/packet.h>
- * file;
- *
- * not all versions of glibc2 have a <netpacket/packet.h> file
- * that defines stuff needed for some of the 2.4-or-later-kernel
- * features, so if the system has a 2.4 or later kernel, we
- * still can't use those features.
- *
- * We're already including a number of other <linux/XXX.h> headers, and
- * this code is Linux-specific (no other OS has PF_PACKET sockets as
- * a raw packet capture mechanism), so it's not as if you gain any
- * useful portability by using <netpacket/packet.h>
- *
- * XXX - should we just include <linux/if_packet.h> even if PF_PACKET
- * isn't defined? It only defines one data structure in 2.0.x, so
- * it shouldn't cause any problems.
- */
- #ifdef PF_PACKET
- # include <linux/if_packet.h>
- /*
- * On at least some Linux distributions (for example, Red Hat 5.2),
- * there's no <netpacket/packet.h> file, but PF_PACKET is defined if
- * you include <sys/socket.h>, but <linux/if_packet.h> doesn't define
- * any of the PF_PACKET stuff such as "struct sockaddr_ll" or any of
- * the PACKET_xxx stuff.
- *
- * So we check whether PACKET_HOST is defined, and assume that we have
- * PF_PACKET sockets only if it is defined.
- */
- # ifdef PACKET_HOST
- # define HAVE_PF_PACKET_SOCKETS
- # ifdef PACKET_AUXDATA
- # define HAVE_PACKET_AUXDATA
- # endif /* PACKET_AUXDATA */
- # endif /* PACKET_HOST */
- /* check for memory mapped access avaibility. We assume every needed
- * struct is defined if the macro TPACKET_HDRLEN is defined, because it
- * uses many ring related structs and macros */
- # ifdef PCAP_SUPPORT_PACKET_RING
- # ifdef TPACKET_HDRLEN
- # define HAVE_PACKET_RING
- # ifdef TPACKET3_HDRLEN
- # define HAVE_TPACKET3
- # endif /* TPACKET3_HDRLEN */
- # ifdef TPACKET2_HDRLEN
- # define HAVE_TPACKET2
- # else /* TPACKET2_HDRLEN */
- # define TPACKET_V1 0 /* Old kernel with only V1, so no TPACKET_Vn defined */
- # endif /* TPACKET2_HDRLEN */
- # endif /* TPACKET_HDRLEN */
- # endif /* PCAP_SUPPORT_PACKET_RING */
- #endif /* PF_PACKET */
- #ifdef SO_ATTACH_FILTER
- #include <linux/types.h>
- #include <linux/filter.h>
- #endif
- #ifdef HAVE_LINUX_NET_TSTAMP_H
- #include <linux/net_tstamp.h>
- #endif
- #ifdef HAVE_LINUX_SOCKIOS_H
- #include <linux/sockios.h>
- #endif
- #ifdef HAVE_LINUX_IF_BONDING_H
- #include <linux/if_bonding.h>
- #endif
- /*
- * Got Wireless Extensions?
- */
- #ifdef HAVE_LINUX_WIRELESS_H
- #include <linux/wireless.h>
- #endif /* HAVE_LINUX_WIRELESS_H */
- /*
- * Got libnl?
- */
- #ifdef HAVE_LIBNL
- #include <linux/nl80211.h>
- #include <netlink/genl/genl.h>
- #include <netlink/genl/family.h>
- #include <netlink/genl/ctrl.h>
- #include <netlink/msg.h>
- #include <netlink/attr.h>
- #endif /* HAVE_LIBNL */
- /*
- * Got ethtool support?
- */
- #ifdef HAVE_LINUX_ETHTOOL_H
- #include <linux/ethtool.h>
- #endif
- #ifndef HAVE_SOCKLEN_T
- typedef int socklen_t;
- #endif
- #ifndef MSG_TRUNC
- /*
- * This is being compiled on a system that lacks MSG_TRUNC; define it
- * with the value it has in the 2.2 and later kernels, so that, on
- * those kernels, when we pass it in the flags argument to "recvfrom()"
- * we're passing the right value and thus get the MSG_TRUNC behavior
- * we want. (We don't get that behavior on 2.0[.x] kernels, because
- * they didn't support MSG_TRUNC.)
- */
- #define MSG_TRUNC 0x20
- #endif
- #ifndef SOL_PACKET
- /*
- * This is being compiled on a system that lacks SOL_PACKET; define it
- * with the value it has in the 2.2 and later kernels, so that we can
- * set promiscuous mode in the good modern way rather than the old
- * 2.0-kernel crappy way.
- */
- #define SOL_PACKET 263
- #endif
- #define MAX_LINKHEADER_SIZE 256
- /*
- * When capturing on all interfaces we use this as the buffer size.
- * Should be bigger then all MTUs that occur in real life.
- * 64kB should be enough for now.
- */
- #define BIGGER_THAN_ALL_MTUS (64*1024)
- /*
- * Private data for capturing on Linux SOCK_PACKET or PF_PACKET sockets.
- */
- struct pcap_linux {
- u_int packets_read; /* count of packets read with recvfrom() */
- long proc_dropped; /* packets reported dropped by /proc/net/dev */
- struct pcap_stat stat;
- char *device; /* device name */
- int filter_in_userland; /* must filter in userland */
- int blocks_to_filter_in_userland;
- int must_do_on_close; /* stuff we must do when we close */
- int timeout; /* timeout for buffering */
- int sock_packet; /* using Linux 2.0 compatible interface */
- int cooked; /* using SOCK_DGRAM rather than SOCK_RAW */
- int ifindex; /* interface index of device we're bound to */
- int lo_ifindex; /* interface index of the loopback device */
- bpf_u_int32 oldmode; /* mode to restore when turning monitor mode off */
- char *mondevice; /* mac80211 monitor device we created */
- u_char *mmapbuf; /* memory-mapped region pointer */
- size_t mmapbuflen; /* size of region */
- int vlan_offset; /* offset at which to insert vlan tags; if -1, don't insert */
- u_int tp_version; /* version of tpacket_hdr for mmaped ring */
- u_int tp_hdrlen; /* hdrlen of tpacket_hdr for mmaped ring */
- u_char *oneshot_buffer; /* buffer for copy of packet */
- #ifdef HAVE_TPACKET3
- unsigned char *current_packet; /* Current packet within the TPACKET_V3 block. Move to next block if NULL. */
- int packets_left; /* Unhandled packets left within the block from previous call to pcap_read_linux_mmap_v3 in case of TPACKET_V3. */
- #endif
- };
- /*
- * Stuff to do when we close.
- */
- #define MUST_CLEAR_PROMISC 0x00000001 /* clear promiscuous mode */
- #define MUST_CLEAR_RFMON 0x00000002 /* clear rfmon (monitor) mode */
- #define MUST_DELETE_MONIF 0x00000004 /* delete monitor-mode interface */
- /*
- * Prototypes for internal functions and methods.
- */
- static void map_arphrd_to_dlt(pcap_t *, int, int, const char *, int);
- #ifdef HAVE_PF_PACKET_SOCKETS
- static short int map_packet_type_to_sll_type(short int);
- #endif
- static int pcap_activate_linux(pcap_t *);
- static int activate_old(pcap_t *);
- static int activate_new(pcap_t *);
- static int activate_mmap(pcap_t *, int *);
- static int pcap_can_set_rfmon_linux(pcap_t *);
- static int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *);
- static int pcap_read_packet(pcap_t *, pcap_handler, u_char *);
- static int pcap_inject_linux(pcap_t *, const void *, size_t);
- static int pcap_stats_linux(pcap_t *, struct pcap_stat *);
- static int pcap_setfilter_linux(pcap_t *, struct bpf_program *);
- static int pcap_setdirection_linux(pcap_t *, pcap_direction_t);
- static int pcap_set_datalink_linux(pcap_t *, int);
- static void pcap_cleanup_linux(pcap_t *);
- /*
- * This is what the header structure looks like in a 64-bit kernel;
- * we use this, rather than struct tpacket_hdr, if we're using
- * TPACKET_V1 in 32-bit code running on a 64-bit kernel.
- */
- struct tpacket_hdr_64 {
- uint64_t tp_status;
- unsigned int tp_len;
- unsigned int tp_snaplen;
- unsigned short tp_mac;
- unsigned short tp_net;
- unsigned int tp_sec;
- unsigned int tp_usec;
- };
- /*
- * We use this internally as the tpacket version for TPACKET_V1 in
- * 32-bit code on a 64-bit kernel.
- */
- #define TPACKET_V1_64 99
- union thdr {
- struct tpacket_hdr *h1;
- struct tpacket_hdr_64 *h1_64;
- #ifdef HAVE_TPACKET2
- struct tpacket2_hdr *h2;
- #endif
- #ifdef HAVE_TPACKET3
- struct tpacket_block_desc *h3;
- #endif
- void *raw;
- };
- #ifdef HAVE_PACKET_RING
- #define RING_GET_FRAME(h) (((union thdr **)h->buffer)[h->offset])
- static void destroy_ring(pcap_t *handle);
- static int create_ring(pcap_t *handle, int *status);
- static int prepare_tpacket_socket(pcap_t *handle);
- static void pcap_cleanup_linux_mmap(pcap_t *);
- static int pcap_read_linux_mmap_v1(pcap_t *, int, pcap_handler , u_char *);
- static int pcap_read_linux_mmap_v1_64(pcap_t *, int, pcap_handler , u_char *);
- #ifdef HAVE_TPACKET2
- static int pcap_read_linux_mmap_v2(pcap_t *, int, pcap_handler , u_char *);
- #endif
- #ifdef HAVE_TPACKET3
- static int pcap_read_linux_mmap_v3(pcap_t *, int, pcap_handler , u_char *);
- #endif
- static int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *);
- static int pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf);
- static int pcap_getnonblock_mmap(pcap_t *p, char *errbuf);
- static void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
- const u_char *bytes);
- #endif
- #ifdef TP_STATUS_VLAN_TPID_VALID
- # define VLAN_TPID(hdr, hv) (((hv)->tp_vlan_tpid || ((hdr)->tp_status & TP_STATUS_VLAN_TPID_VALID)) ? (hv)->tp_vlan_tpid : ETH_P_8021Q)
- #else
- # define VLAN_TPID(hdr, hv) ETH_P_8021Q
- #endif
- /*
- * Wrap some ioctl calls
- */
- #ifdef HAVE_PF_PACKET_SOCKETS
- static int iface_get_id(int fd, const char *device, char *ebuf);
- #endif /* HAVE_PF_PACKET_SOCKETS */
- static int iface_get_mtu(int fd, const char *device, char *ebuf);
- static int iface_get_arptype(int fd, const char *device, char *ebuf);
- #ifdef HAVE_PF_PACKET_SOCKETS
- static int iface_bind(int fd, int ifindex, char *ebuf);
- #ifdef IW_MODE_MONITOR
- static int has_wext(int sock_fd, const char *device, char *ebuf);
- #endif /* IW_MODE_MONITOR */
- static int enter_rfmon_mode(pcap_t *handle, int sock_fd,
- const char *device);
- #endif /* HAVE_PF_PACKET_SOCKETS */
- #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
- static int iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf);
- #endif
- #ifdef HAVE_PACKET_RING
- static int iface_get_offload(pcap_t *handle);
- #endif
- static int iface_bind_old(int fd, const char *device, char *ebuf);
- #ifdef SO_ATTACH_FILTER
- static int fix_program(pcap_t *handle, struct sock_fprog *fcode,
- int is_mapped);
- static int fix_offset(struct bpf_insn *p);
- static int set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode);
- static int reset_kernel_filter(pcap_t *handle);
- static struct sock_filter total_insn
- = BPF_STMT(BPF_RET | BPF_K, 0);
- static struct sock_fprog total_fcode
- = { 1, &total_insn };
- #endif /* SO_ATTACH_FILTER */
- pcap_t *
- pcap_create_interface(const char *device, char *ebuf)
- {
- pcap_t *handle;
- handle = pcap_create_common(device, ebuf, sizeof (struct pcap_linux));
- if (handle == NULL)
- return NULL;
- handle->activate_op = pcap_activate_linux;
- handle->can_set_rfmon_op = pcap_can_set_rfmon_linux;
- #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
- /*
- * See what time stamp types we support.
- */
- if (iface_ethtool_get_ts_info(handle, ebuf) == -1) {
- free(handle);
- return NULL;
- }
- #endif
- #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
- /*
- * We claim that we support microsecond and nanosecond time
- * stamps.
- *
- * XXX - with adapter-supplied time stamps, can we choose
- * microsecond or nanosecond time stamps on arbitrary
- * adapters?
- */
- handle->tstamp_precision_count = 2;
- handle->tstamp_precision_list = malloc(2 * sizeof(u_int));
- if (handle->tstamp_precision_list == NULL) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
- pcap_strerror(errno));
- if (handle->tstamp_type_list != NULL)
- free(handle->tstamp_type_list);
- free(handle);
- return NULL;
- }
- handle->tstamp_precision_list[0] = PCAP_TSTAMP_PRECISION_MICRO;
- handle->tstamp_precision_list[1] = PCAP_TSTAMP_PRECISION_NANO;
- #endif /* defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS) */
- return handle;
- }
- #ifdef HAVE_LIBNL
- /*
- * If interface {if} is a mac80211 driver, the file
- * /sys/class/net/{if}/phy80211 is a symlink to
- * /sys/class/ieee80211/{phydev}, for some {phydev}.
- *
- * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
- * least, has a "wmaster0" device and a "wlan0" device; the
- * latter is the one with the IP address. Both show up in
- * "tcpdump -D" output. Capturing on the wmaster0 device
- * captures with 802.11 headers.
- *
- * airmon-ng searches through /sys/class/net for devices named
- * monN, starting with mon0; as soon as one *doesn't* exist,
- * it chooses that as the monitor device name. If the "iw"
- * command exists, it does "iw dev {if} interface add {monif}
- * type monitor", where {monif} is the monitor device. It
- * then (sigh) sleeps .1 second, and then configures the
- * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
- * is a file, it writes {mondev}, without a newline, to that file,
- * and again (sigh) sleeps .1 second, and then iwconfig's that
- * device into monitor mode and configures it up. Otherwise,
- * you can't do monitor mode.
- *
- * All these devices are "glued" together by having the
- * /sys/class/net/{device}/phy80211 links pointing to the same
- * place, so, given a wmaster, wlan, or mon device, you can
- * find the other devices by looking for devices with
- * the same phy80211 link.
- *
- * To turn monitor mode off, delete the monitor interface,
- * either with "iw dev {monif} interface del" or by sending
- * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
- *
- * Note: if you try to create a monitor device named "monN", and
- * there's already a "monN" device, it fails, as least with
- * the netlink interface (which is what iw uses), with a return
- * value of -ENFILE. (Return values are negative errnos.) We
- * could probably use that to find an unused device.
- *
- * Yes, you can have multiple monitor devices for a given
- * physical device.
- */
- /*
- * Is this a mac80211 device? If so, fill in the physical device path and
- * return 1; if not, return 0. On an error, fill in handle->errbuf and
- * return PCAP_ERROR.
- */
- static int
- get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path,
- size_t phydev_max_pathlen)
- {
- char *pathstr;
- ssize_t bytes_read;
- /*
- * Generate the path string for the symlink to the physical device.
- */
- if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't generate path name string for /sys/class/net device",
- device);
- return PCAP_ERROR;
- }
- bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen);
- if (bytes_read == -1) {
- if (errno == ENOENT || errno == EINVAL) {
- /*
- * Doesn't exist, or not a symlink; assume that
- * means it's not a mac80211 device.
- */
- free(pathstr);
- return 0;
- }
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't readlink %s: %s", device, pathstr,
- strerror(errno));
- free(pathstr);
- return PCAP_ERROR;
- }
- free(pathstr);
- phydev_path[bytes_read] = '\0';
- return 1;
- }
- #ifdef HAVE_LIBNL_SOCKETS
- #define get_nl_errmsg nl_geterror
- #else
- /* libnl 2.x compatibility code */
- #define nl_sock nl_handle
- static inline struct nl_handle *
- nl_socket_alloc(void)
- {
- return nl_handle_alloc();
- }
- static inline void
- nl_socket_free(struct nl_handle *h)
- {
- nl_handle_destroy(h);
- }
- #define get_nl_errmsg strerror
- static inline int
- __genl_ctrl_alloc_cache(struct nl_handle *h, struct nl_cache **cache)
- {
- struct nl_cache *tmp = genl_ctrl_alloc_cache(h);
- if (!tmp)
- return -ENOMEM;
- *cache = tmp;
- return 0;
- }
- #define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache
- #endif /* !HAVE_LIBNL_SOCKETS */
- struct nl80211_state {
- struct nl_sock *nl_sock;
- struct nl_cache *nl_cache;
- struct genl_family *nl80211;
- };
- static int
- nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
- {
- int err;
- state->nl_sock = nl_socket_alloc();
- if (!state->nl_sock) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: failed to allocate netlink handle", device);
- return PCAP_ERROR;
- }
- if (genl_connect(state->nl_sock)) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: failed to connect to generic netlink", device);
- goto out_handle_destroy;
- }
- err = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
- if (err < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: failed to allocate generic netlink cache: %s",
- device, get_nl_errmsg(-err));
- goto out_handle_destroy;
- }
- state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
- if (!state->nl80211) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl80211 not found", device);
- goto out_cache_free;
- }
- return 0;
- out_cache_free:
- nl_cache_free(state->nl_cache);
- out_handle_destroy:
- nl_socket_free(state->nl_sock);
- return PCAP_ERROR;
- }
- static void
- nl80211_cleanup(struct nl80211_state *state)
- {
- genl_family_put(state->nl80211);
- nl_cache_free(state->nl_cache);
- nl_socket_free(state->nl_sock);
- }
- static int
- add_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
- const char *device, const char *mondevice)
- {
- int ifindex;
- struct nl_msg *msg;
- int err;
- ifindex = iface_get_id(sock_fd, device, handle->errbuf);
- if (ifindex == -1)
- return PCAP_ERROR;
- msg = nlmsg_alloc();
- if (!msg) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: failed to allocate netlink msg", device);
- return PCAP_ERROR;
- }
- genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
- 0, NL80211_CMD_NEW_INTERFACE, 0);
- NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
- NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
- NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
- err = nl_send_auto_complete(state->nl_sock, msg);
- if (err < 0) {
- #if defined HAVE_LIBNL_NLE
- if (err == -NLE_FAILURE) {
- #else
- if (err == -ENFILE) {
- #endif
- /*
- * Device not available; our caller should just
- * keep trying. (libnl 2.x maps ENFILE to
- * NLE_FAILURE; it can also map other errors
- * to that, but there's not much we can do
- * about that.)
- */
- nlmsg_free(msg);
- return 0;
- } else {
- /*
- * Real failure, not just "that device is not
- * available.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl_send_auto_complete failed adding %s interface: %s",
- device, mondevice, get_nl_errmsg(-err));
- nlmsg_free(msg);
- return PCAP_ERROR;
- }
- }
- err = nl_wait_for_ack(state->nl_sock);
- if (err < 0) {
- #if defined HAVE_LIBNL_NLE
- if (err == -NLE_FAILURE) {
- #else
- if (err == -ENFILE) {
- #endif
- /*
- * Device not available; our caller should just
- * keep trying. (libnl 2.x maps ENFILE to
- * NLE_FAILURE; it can also map other errors
- * to that, but there's not much we can do
- * about that.)
- */
- nlmsg_free(msg);
- return 0;
- } else {
- /*
- * Real failure, not just "that device is not
- * available.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl_wait_for_ack failed adding %s interface: %s",
- device, mondevice, get_nl_errmsg(-err));
- nlmsg_free(msg);
- return PCAP_ERROR;
- }
- }
- /*
- * Success.
- */
- nlmsg_free(msg);
- return 1;
- nla_put_failure:
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl_put failed adding %s interface",
- device, mondevice);
- nlmsg_free(msg);
- return PCAP_ERROR;
- }
- static int
- del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
- const char *device, const char *mondevice)
- {
- int ifindex;
- struct nl_msg *msg;
- int err;
- ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf);
- if (ifindex == -1)
- return PCAP_ERROR;
- msg = nlmsg_alloc();
- if (!msg) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: failed to allocate netlink msg", device);
- return PCAP_ERROR;
- }
- genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
- 0, NL80211_CMD_DEL_INTERFACE, 0);
- NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
- err = nl_send_auto_complete(state->nl_sock, msg);
- if (err < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl_send_auto_complete failed deleting %s interface: %s",
- device, mondevice, get_nl_errmsg(-err));
- nlmsg_free(msg);
- return PCAP_ERROR;
- }
- err = nl_wait_for_ack(state->nl_sock);
- if (err < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl_wait_for_ack failed adding %s interface: %s",
- device, mondevice, get_nl_errmsg(-err));
- nlmsg_free(msg);
- return PCAP_ERROR;
- }
- /*
- * Success.
- */
- nlmsg_free(msg);
- return 1;
- nla_put_failure:
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: nl_put failed deleting %s interface",
- device, mondevice);
- nlmsg_free(msg);
- return PCAP_ERROR;
- }
- static int
- enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device)
- {
- struct pcap_linux *handlep = handle->priv;
- int ret;
- char phydev_path[PATH_MAX+1];
- struct nl80211_state nlstate;
- struct ifreq ifr;
- u_int n;
- /*
- * Is this a mac80211 device?
- */
- ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX);
- if (ret < 0)
- return ret; /* error */
- if (ret == 0)
- return 0; /* no error, but not mac80211 device */
- /*
- * XXX - is this already a monN device?
- * If so, we're done.
- * Is that determined by old Wireless Extensions ioctls?
- */
- /*
- * OK, it's apparently a mac80211 device.
- * Try to find an unused monN device for it.
- */
- ret = nl80211_init(handle, &nlstate, device);
- if (ret != 0)
- return ret;
- for (n = 0; n < UINT_MAX; n++) {
- /*
- * Try mon{n}.
- */
- char mondevice[3+10+1]; /* mon{UINT_MAX}\0 */
- snprintf(mondevice, sizeof mondevice, "mon%u", n);
- ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice);
- if (ret == 1) {
- handlep->mondevice = strdup(mondevice);
- goto added;
- }
- if (ret < 0) {
- /*
- * Hard failure. Just return ret; handle->errbuf
- * has already been set.
- */
- nl80211_cleanup(&nlstate);
- return ret;
- }
- }
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: No free monN interfaces", device);
- nl80211_cleanup(&nlstate);
- return PCAP_ERROR;
- added:
- #if 0
- /*
- * Sleep for .1 seconds.
- */
- delay.tv_sec = 0;
- delay.tv_nsec = 500000000;
- nanosleep(&delay, NULL);
- #endif
- /*
- * If we haven't already done so, arrange to have
- * "pcap_close_all()" called when we exit.
- */
- if (!pcap_do_addexit(handle)) {
- /*
- * "atexit()" failed; don't put the interface
- * in rfmon mode, just give up.
- */
- return PCAP_ERROR_RFMON_NOTSUP;
- }
- /*
- * Now configure the monitor interface up.
- */
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, handlep->mondevice, sizeof(ifr.ifr_name));
- if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't get flags for %s: %s", device,
- handlep->mondevice, strerror(errno));
- del_mon_if(handle, sock_fd, &nlstate, device,
- handlep->mondevice);
- nl80211_cleanup(&nlstate);
- return PCAP_ERROR;
- }
- ifr.ifr_flags |= IFF_UP|IFF_RUNNING;
- if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't set flags for %s: %s", device,
- handlep->mondevice, strerror(errno));
- del_mon_if(handle, sock_fd, &nlstate, device,
- handlep->mondevice);
- nl80211_cleanup(&nlstate);
- return PCAP_ERROR;
- }
- /*
- * Success. Clean up the libnl state.
- */
- nl80211_cleanup(&nlstate);
- /*
- * Note that we have to delete the monitor device when we close
- * the handle.
- */
- handlep->must_do_on_close |= MUST_DELETE_MONIF;
- /*
- * Add this to the list of pcaps to close when we exit.
- */
- pcap_add_to_pcaps_to_close(handle);
- return 1;
- }
- #endif /* HAVE_LIBNL */
- #ifdef IW_MODE_MONITOR
- /*
- * Bonding devices mishandle unknown ioctls; they fail with ENODEV
- * rather than ENOTSUP, EOPNOTSUPP, or ENOTTY, so Wireless Extensions
- * will fail with ENODEV if we try to do them on a bonding device,
- * making us return a "no such device" indication rather than just
- * saying "no Wireless Extensions".
- *
- * So we check for bonding devices, if we can, before trying those
- * ioctls, by trying a bonding device information query ioctl to see
- * whether it succeeds.
- */
- static int
- is_bonding_device(int fd, const char *device)
- {
- #if defined(BOND_INFO_QUERY_OLD) || defined(SIOCBONDINFOQUERY)
- struct ifreq ifr;
- ifbond ifb;
- memset(&ifr, 0, sizeof ifr);
- strlcpy(ifr.ifr_name, device, sizeof ifr.ifr_name);
- memset(&ifb, 0, sizeof ifb);
- ifr.ifr_data = (caddr_t)&ifb;
- #ifdef SIOCBONDINFOQUERY
- if (ioctl(fd, SIOCBONDINFOQUERY, &ifr) == 0)
- #else /* SIOCBONDINFOQUERY */
- if (ioctl(fd, BOND_INFO_QUERY_OLD, &ifr) == 0)
- #endif /* SIOCBONDINFOQUERY */
- return 1; /* success, so it's a bonding device */
- #endif /* defined(BOND_INFO_QUERY_OLD) || defined(SIOCBONDINFOQUERY) */
- return 0; /* no, it's not a bonding device */
- }
- #endif /* IW_MODE_MONITOR */
- static int
- pcap_can_set_rfmon_linux(pcap_t *handle)
- {
- #ifdef HAVE_LIBNL
- char phydev_path[PATH_MAX+1];
- int ret;
- #endif
- #ifdef IW_MODE_MONITOR
- int sock_fd;
- struct iwreq ireq;
- #endif
- if (strcmp(handle->opt.source, "any") == 0) {
- /*
- * Monitor mode makes no sense on the "any" device.
- */
- return 0;
- }
- #ifdef HAVE_LIBNL
- /*
- * Bleah. There doesn't seem to be a way to ask a mac80211
- * device, through libnl, whether it supports monitor mode;
- * we'll just check whether the device appears to be a
- * mac80211 device and, if so, assume the device supports
- * monitor mode.
- *
- * wmaster devices don't appear to support the Wireless
- * Extensions, but we can create a mon device for a
- * wmaster device, so we don't bother checking whether
- * a mac80211 device supports the Wireless Extensions.
- */
- ret = get_mac80211_phydev(handle, handle->opt.source, phydev_path,
- PATH_MAX);
- if (ret < 0)
- return ret; /* error */
- if (ret == 1)
- return 1; /* mac80211 device */
- #endif
- #ifdef IW_MODE_MONITOR
- /*
- * Bleah. There doesn't appear to be an ioctl to use to ask
- * whether a device supports monitor mode; we'll just do
- * SIOCGIWMODE and, if it succeeds, assume the device supports
- * monitor mode.
- *
- * Open a socket on which to attempt to get the mode.
- * (We assume that if we have Wireless Extensions support
- * we also have PF_PACKET support.)
- */
- sock_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
- if (sock_fd == -1) {
- (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- if (is_bonding_device(sock_fd, handle->opt.source)) {
- /* It's a bonding device, so don't even try. */
- close(sock_fd);
- return 0;
- }
- /*
- * Attempt to get the current mode.
- */
- strlcpy(ireq.ifr_ifrn.ifrn_name, handle->opt.source,
- sizeof ireq.ifr_ifrn.ifrn_name);
- if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) {
- /*
- * Well, we got the mode; assume we can set it.
- */
- close(sock_fd);
- return 1;
- }
- if (errno == ENODEV) {
- /* The device doesn't even exist. */
- (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SIOCGIWMODE failed: %s", pcap_strerror(errno));
- close(sock_fd);
- return PCAP_ERROR_NO_SUCH_DEVICE;
- }
- close(sock_fd);
- #endif
- return 0;
- }
- /*
- * Grabs the number of dropped packets by the interface from /proc/net/dev.
- *
- * XXX - what about /sys/class/net/{interface name}/rx_*? There are
- * individual devices giving, in ASCII, various rx_ and tx_ statistics.
- *
- * Or can we get them in binary form from netlink?
- */
- static long int
- linux_if_drops(const char * if_name)
- {
- char buffer[512];
- char * bufptr;
- FILE * file;
- int field_to_convert = 3, if_name_sz = strlen(if_name);
- long int dropped_pkts = 0;
- file = fopen("/proc/net/dev", "r");
- if (!file)
- return 0;
- while (!dropped_pkts && fgets( buffer, sizeof(buffer), file ))
- {
- /* search for 'bytes' -- if its in there, then
- that means we need to grab the fourth field. otherwise
- grab the third field. */
- if (field_to_convert != 4 && strstr(buffer, "bytes"))
- {
- field_to_convert = 4;
- continue;
- }
- /* find iface and make sure it actually matches -- space before the name and : after it */
- if ((bufptr = strstr(buffer, if_name)) &&
- (bufptr == buffer || *(bufptr-1) == ' ') &&
- *(bufptr + if_name_sz) == ':')
- {
- bufptr = bufptr + if_name_sz + 1;
- /* grab the nth field from it */
- while( --field_to_convert && *bufptr != '\0')
- {
- while (*bufptr != '\0' && *(bufptr++) == ' ');
- while (*bufptr != '\0' && *(bufptr++) != ' ');
- }
- /* get rid of any final spaces */
- while (*bufptr != '\0' && *bufptr == ' ') bufptr++;
- if (*bufptr != '\0')
- dropped_pkts = strtol(bufptr, NULL, 10);
- break;
- }
- }
- fclose(file);
- return dropped_pkts;
- }
- /*
- * With older kernels promiscuous mode is kind of interesting because we
- * have to reset the interface before exiting. The problem can't really
- * be solved without some daemon taking care of managing usage counts.
- * If we put the interface into promiscuous mode, we set a flag indicating
- * that we must take it out of that mode when the interface is closed,
- * and, when closing the interface, if that flag is set we take it out
- * of promiscuous mode.
- *
- * Even with newer kernels, we have the same issue with rfmon mode.
- */
- static void pcap_cleanup_linux( pcap_t *handle )
- {
- struct pcap_linux *handlep = handle->priv;
- struct ifreq ifr;
- #ifdef HAVE_LIBNL
- struct nl80211_state nlstate;
- int ret;
- #endif /* HAVE_LIBNL */
- #ifdef IW_MODE_MONITOR
- int oldflags;
- struct iwreq ireq;
- #endif /* IW_MODE_MONITOR */
- if (handlep->must_do_on_close != 0) {
- /*
- * There's something we have to do when closing this
- * pcap_t.
- */
- if (handlep->must_do_on_close & MUST_CLEAR_PROMISC) {
- /*
- * We put the interface into promiscuous mode;
- * take it out of promiscuous mode.
- *
- * XXX - if somebody else wants it in promiscuous
- * mode, this code cannot know that, so it'll take
- * it out of promiscuous mode. That's not fixable
- * in 2.0[.x] kernels.
- */
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, handlep->device,
- sizeof(ifr.ifr_name));
- if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
- fprintf(stderr,
- "Can't restore interface %s flags (SIOCGIFFLAGS failed: %s).\n"
- "Please adjust manually.\n"
- "Hint: This can't happen with Linux >= 2.2.0.\n",
- handlep->device, strerror(errno));
- } else {
- if (ifr.ifr_flags & IFF_PROMISC) {
- /*
- * Promiscuous mode is currently on;
- * turn it off.
- */
- ifr.ifr_flags &= ~IFF_PROMISC;
- if (ioctl(handle->fd, SIOCSIFFLAGS,
- &ifr) == -1) {
- fprintf(stderr,
- "Can't restore interface %s flags (SIOCSIFFLAGS failed: %s).\n"
- "Please adjust manually.\n"
- "Hint: This can't happen with Linux >= 2.2.0.\n",
- handlep->device,
- strerror(errno));
- }
- }
- }
- }
- #ifdef HAVE_LIBNL
- if (handlep->must_do_on_close & MUST_DELETE_MONIF) {
- ret = nl80211_init(handle, &nlstate, handlep->device);
- if (ret >= 0) {
- ret = del_mon_if(handle, handle->fd, &nlstate,
- handlep->device, handlep->mondevice);
- nl80211_cleanup(&nlstate);
- }
- if (ret < 0) {
- fprintf(stderr,
- "Can't delete monitor interface %s (%s).\n"
- "Please delete manually.\n",
- handlep->mondevice, handle->errbuf);
- }
- }
- #endif /* HAVE_LIBNL */
- #ifdef IW_MODE_MONITOR
- if (handlep->must_do_on_close & MUST_CLEAR_RFMON) {
- /*
- * We put the interface into rfmon mode;
- * take it out of rfmon mode.
- *
- * XXX - if somebody else wants it in rfmon
- * mode, this code cannot know that, so it'll take
- * it out of rfmon mode.
- */
- /*
- * First, take the interface down if it's up;
- * otherwise, we might get EBUSY.
- * If we get errors, just drive on and print
- * a warning if we can't restore the mode.
- */
- oldflags = 0;
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, handlep->device,
- sizeof(ifr.ifr_name));
- if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) != -1) {
- if (ifr.ifr_flags & IFF_UP) {
- oldflags = ifr.ifr_flags;
- ifr.ifr_flags &= ~IFF_UP;
- if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1)
- oldflags = 0; /* didn't set, don't restore */
- }
- }
- /*
- * Now restore the mode.
- */
- strlcpy(ireq.ifr_ifrn.ifrn_name, handlep->device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- ireq.u.mode = handlep->oldmode;
- if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
- /*
- * Scientist, you've failed.
- */
- fprintf(stderr,
- "Can't restore interface %s wireless mode (SIOCSIWMODE failed: %s).\n"
- "Please adjust manually.\n",
- handlep->device, strerror(errno));
- }
- /*
- * Now bring the interface back up if we brought
- * it down.
- */
- if (oldflags != 0) {
- ifr.ifr_flags = oldflags;
- if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
- fprintf(stderr,
- "Can't bring interface %s back up (SIOCSIFFLAGS failed: %s).\n"
- "Please adjust manually.\n",
- handlep->device, strerror(errno));
- }
- }
- }
- #endif /* IW_MODE_MONITOR */
- /*
- * Take this pcap out of the list of pcaps for which we
- * have to take the interface out of some mode.
- */
- pcap_remove_from_pcaps_to_close(handle);
- }
- if (handlep->mondevice != NULL) {
- free(handlep->mondevice);
- handlep->mondevice = NULL;
- }
- if (handlep->device != NULL) {
- free(handlep->device);
- handlep->device = NULL;
- }
- pcap_cleanup_live_common(handle);
- }
- /*
- * Get a handle for a live capture from the given device. You can
- * pass NULL as device to get all packages (without link level
- * information of course). If you pass 1 as promisc the interface
- * will be set to promiscous mode (XXX: I think this usage should
- * be deprecated and functions be added to select that later allow
- * modification of that values -- Torsten).
- */
- static int
- pcap_activate_linux(pcap_t *handle)
- {
- struct pcap_linux *handlep = handle->priv;
- const char *device;
- struct ifreq ifr;
- int status = 0;
- int ret;
- device = handle->opt.source;
- /*
- * Make sure the name we were handed will fit into the ioctls we
- * might perform on the device; if not, return a "No such device"
- * indication, as the Linux kernel shouldn't support creating
- * a device whose name won't fit into those ioctls.
- *
- * "Will fit" means "will fit, complete with a null terminator",
- * so if the length, which does *not* include the null terminator,
- * is greater than *or equal to* the size of the field into which
- * we'll be copying it, that won't fit.
- */
- if (strlen(device) >= sizeof(ifr.ifr_name)) {
- status = PCAP_ERROR_NO_SUCH_DEVICE;
- goto fail;
- }
- handle->inject_op = pcap_inject_linux;
- handle->setfilter_op = pcap_setfilter_linux;
- handle->setdirection_op = pcap_setdirection_linux;
- handle->set_datalink_op = pcap_set_datalink_linux;
- handle->getnonblock_op = pcap_getnonblock_fd;
- handle->setnonblock_op = pcap_setnonblock_fd;
- handle->cleanup_op = pcap_cleanup_linux;
- handle->read_op = pcap_read_linux;
- handle->stats_op = pcap_stats_linux;
- /*
- * The "any" device is a special device which causes us not
- * to bind to a particular device and thus to look at all
- * devices.
- */
- if (strcmp(device, "any") == 0) {
- if (handle->opt.promisc) {
- handle->opt.promisc = 0;
- /* Just a warning. */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "Promiscuous mode not supported on the \"any\" device");
- status = PCAP_WARNING_PROMISC_NOTSUP;
- }
- }
- handlep->device = strdup(device);
- if (handlep->device == NULL) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
- pcap_strerror(errno) );
- return PCAP_ERROR;
- }
- /* copy timeout value */
- handlep->timeout = handle->opt.timeout;
- /*
- * If we're in promiscuous mode, then we probably want
- * to see when the interface drops packets too, so get an
- * initial count from /proc/net/dev
- */
- if (handle->opt.promisc)
- handlep->proc_dropped = linux_if_drops(handlep->device);
- /*
- * Current Linux kernels use the protocol family PF_PACKET to
- * allow direct access to all packets on the network while
- * older kernels had a special socket type SOCK_PACKET to
- * implement this feature.
- * While this old implementation is kind of obsolete we need
- * to be compatible with older kernels for a while so we are
- * trying both methods with the newer method preferred.
- */
- ret = activate_new(handle);
- if (ret < 0) {
- /*
- * Fatal error with the new way; just fail.
- * ret has the error return; if it's PCAP_ERROR,
- * handle->errbuf has been set appropriately.
- */
- status = ret;
- goto fail;
- }
- if (ret == 1) {
- /*
- * Success.
- * Try to use memory-mapped access.
- */
- switch (activate_mmap(handle, &status)) {
- case 1:
- /*
- * We succeeded. status has been
- * set to the status to return,
- * which might be 0, or might be
- * a PCAP_WARNING_ value.
- */
- return status;
- case 0:
- /*
- * Kernel doesn't support it - just continue
- * with non-memory-mapped access.
- */
- break;
- case -1:
- /*
- * We failed to set up to use it, or the kernel
- * supports it, but we failed to enable it.
- * ret has been set to the error status to
- * return and, if it's PCAP_ERROR, handle->errbuf
- * contains the error message.
- */
- status = ret;
- goto fail;
- }
- }
- else if (ret == 0) {
- /* Non-fatal error; try old way */
- if ((ret = activate_old(handle)) != 1) {
- /*
- * Both methods to open the packet socket failed.
- * Tidy up and report our failure (handle->errbuf
- * is expected to be set by the functions above).
- */
- status = ret;
- goto fail;
- }
- }
- /*
- * We set up the socket, but not with memory-mapped access.
- */
- if (handle->opt.buffer_size != 0) {
- /*
- * Set the socket buffer size to the specified value.
- */
- if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
- &handle->opt.buffer_size,
- sizeof(handle->opt.buffer_size)) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SO_RCVBUF: %s", pcap_strerror(errno));
- status = PCAP_ERROR;
- goto fail;
- }
- }
- /* Allocate the buffer */
- handle->buffer = malloc(handle->bufsize + handle->offset);
- if (!handle->buffer) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "malloc: %s", pcap_strerror(errno));
- status = PCAP_ERROR;
- goto fail;
- }
- /*
- * "handle->fd" is a socket, so "select()" and "poll()"
- * should work on it.
- */
- handle->selectable_fd = handle->fd;
- return status;
- fail:
- pcap_cleanup_linux(handle);
- return status;
- }
- /*
- * Read at most max_packets from the capture stream and call the callback
- * for each of them. Returns the number of packets handled or -1 if an
- * error occured.
- */
- static int
- pcap_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
- {
- /*
- * Currently, on Linux only one packet is delivered per read,
- * so we don't loop.
- */
- return pcap_read_packet(handle, callback, user);
- }
- static int
- pcap_set_datalink_linux(pcap_t *handle, int dlt)
- {
- handle->linktype = dlt;
- return 0;
- }
- /*
- * linux_check_direction()
- *
- * Do checks based on packet direction.
- */
- static inline int
- linux_check_direction(const pcap_t *handle, const struct sockaddr_ll *sll)
- {
- struct pcap_linux *handlep = handle->priv;
- if (sll->sll_pkttype == PACKET_OUTGOING) {
- /*
- * Outgoing packet.
- * If this is from the loopback device, reject it;
- * we'll see the packet as an incoming packet as well,
- * and we don't want to see it twice.
- */
- if (sll->sll_ifindex == handlep->lo_ifindex)
- return 0;
- /*
- * If the user only wants incoming packets, reject it.
- */
- if (handle->direction == PCAP_D_IN)
- return 0;
- } else {
- /*
- * Incoming packet.
- * If the user only wants outgoing packets, reject it.
- */
- if (handle->direction == PCAP_D_OUT)
- return 0;
- }
- return 1;
- }
- /*
- * Read a packet from the socket calling the handler provided by
- * the user. Returns the number of packets received or -1 if an
- * error occured.
- */
- static int
- pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
- {
- struct pcap_linux *handlep = handle->priv;
- u_char *bp;
- int offset;
- #ifdef HAVE_PF_PACKET_SOCKETS
- struct sockaddr_ll from;
- struct sll_header *hdrp;
- #else
- struct sockaddr from;
- #endif
- #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
- struct iovec iov;
- struct msghdr msg;
- struct cmsghdr *cmsg;
- union {
- struct cmsghdr cmsg;
- char buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))];
- } cmsg_buf;
- #else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
- socklen_t fromlen;
- #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
- int packet_len, caplen;
- struct pcap_pkthdr pcap_header;
- struct bpf_aux_data aux_data;
- #ifdef HAVE_PF_PACKET_SOCKETS
- /*
- * If this is a cooked device, leave extra room for a
- * fake packet header.
- */
- if (handlep->cooked)
- offset = SLL_HDR_LEN;
- else
- offset = 0;
- #else
- /*
- * This system doesn't have PF_PACKET sockets, so it doesn't
- * support cooked devices.
- */
- offset = 0;
- #endif
- /*
- * Receive a single packet from the kernel.
- * We ignore EINTR, as that might just be due to a signal
- * being delivered - if the signal should interrupt the
- * loop, the signal handler should call pcap_breakloop()
- * to set handle->break_loop (we ignore it on other
- * platforms as well).
- * We also ignore ENETDOWN, so that we can continue to
- * capture traffic if the interface goes down and comes
- * back up again; comments in the kernel indicate that
- * we'll just block waiting for packets if we try to
- * receive from a socket that delivered ENETDOWN, and,
- * if we're using a memory-mapped buffer, we won't even
- * get notified of "network down" events.
- */
- bp = handle->buffer + handle->offset;
- #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
- msg.msg_name = &from;
- msg.msg_namelen = sizeof(from);
- msg.msg_iov = &iov;
- msg.msg_iovlen = 1;
- msg.msg_control = &cmsg_buf;
- msg.msg_controllen = sizeof(cmsg_buf);
- msg.msg_flags = 0;
- iov.iov_len = handle->bufsize - offset;
- iov.iov_base = bp + offset;
- #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
- do {
- /*
- * Has "pcap_breakloop()" been called?
- */
- if (handle->break_loop) {
- /*
- * Yes - clear the flag that indicates that it has,
- * and return PCAP_ERROR_BREAK as an indication that
- * we were told to break out of the loop.
- */
- handle->break_loop = 0;
- return PCAP_ERROR_BREAK;
- }
- #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
- packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC);
- #else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
- fromlen = sizeof(from);
- packet_len = recvfrom(
- handle->fd, bp + offset,
- handle->bufsize - offset, MSG_TRUNC,
- (struct sockaddr *) &from, &fromlen);
- #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
- } while (packet_len == -1 && errno == EINTR);
- /* Check if an error occured */
- if (packet_len == -1) {
- switch (errno) {
- case EAGAIN:
- return 0; /* no packet there */
- case ENETDOWN:
- /*
- * The device on which we're capturing went away.
- *
- * XXX - we should really return
- * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch()
- * etc. aren't defined to return that.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "The interface went down");
- return PCAP_ERROR;
- default:
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "recvfrom: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- }
- #ifdef HAVE_PF_PACKET_SOCKETS
- if (!handlep->sock_packet) {
- /*
- * Unfortunately, there is a window between socket() and
- * bind() where the kernel may queue packets from any
- * interface. If we're bound to a particular interface,
- * discard packets not from that interface.
- *
- * (If socket filters are supported, we could do the
- * same thing we do when changing the filter; however,
- * that won't handle packet sockets without socket
- * filter support, and it's a bit more complicated.
- * It would save some instructions per packet, however.)
- */
- if (handlep->ifindex != -1 &&
- from.sll_ifindex != handlep->ifindex)
- return 0;
- /*
- * Do checks based on packet direction.
- * We can only do this if we're using PF_PACKET; the
- * address returned for SOCK_PACKET is a "sockaddr_pkt"
- * which lacks the relevant packet type information.
- */
- if (!linux_check_direction(handle, &from))
- return 0;
- }
- #endif
- #ifdef HAVE_PF_PACKET_SOCKETS
- /*
- * If this is a cooked device, fill in the fake packet header.
- */
- if (handlep->cooked) {
- /*
- * Add the length of the fake header to the length
- * of packet data we read.
- */
- packet_len += SLL_HDR_LEN;
- hdrp = (struct sll_header *)bp;
- hdrp->sll_pkttype = map_packet_type_to_sll_type(from.sll_pkttype);
- hdrp->sll_hatype = htons(from.sll_hatype);
- hdrp->sll_halen = htons(from.sll_halen);
- memcpy(hdrp->sll_addr, from.sll_addr,
- (from.sll_halen > SLL_ADDRLEN) ?
- SLL_ADDRLEN :
- from.sll_halen);
- hdrp->sll_protocol = from.sll_protocol;
- }
- #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
- if (handlep->vlan_offset != -1) {
- for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
- struct tpacket_auxdata *aux;
- unsigned int len;
- struct vlan_tag *tag;
- if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) ||
- cmsg->cmsg_level != SOL_PACKET ||
- cmsg->cmsg_type != PACKET_AUXDATA)
- continue;
- aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg);
- #if defined(TP_STATUS_VLAN_VALID)
- if ((aux->tp_vlan_tci == 0) && !(aux->tp_status & TP_STATUS_VLAN_VALID))
- #else
- if (aux->tp_vlan_tci == 0) /* this is ambigious but without the
- TP_STATUS_VLAN_VALID flag, there is
- nothing that we can do */
- #endif
- continue;
- len = packet_len > iov.iov_len ? iov.iov_len : packet_len;
- if (len < (unsigned int) handlep->vlan_offset)
- break;
- bp -= VLAN_TAG_LEN;
- memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
- tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
- tag->vlan_tpid = htons(VLAN_TPID(aux, aux));
- tag->vlan_tci = htons(aux->tp_vlan_tci);
- /* store vlan tci to bpf_aux_data struct for userland bpf filter */
- #if defined(TP_STATUS_VLAN_VALID)
- aux_data.vlan_tag = htons(aux->tp_vlan_tci) & 0x0fff;
- aux_data.vlan_tag_present = (aux->tp_status & TP_STATUS_VLAN_VALID);
- #endif
- packet_len += VLAN_TAG_LEN;
- }
- }
- #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
- #endif /* HAVE_PF_PACKET_SOCKETS */
- /*
- * XXX: According to the kernel source we should get the real
- * packet len if calling recvfrom with MSG_TRUNC set. It does
- * not seem to work here :(, but it is supported by this code
- * anyway.
- * To be honest the code RELIES on that feature so this is really
- * broken with 2.2.x kernels.
- * I spend a day to figure out what's going on and I found out
- * that the following is happening:
- *
- * The packet comes from a random interface and the packet_rcv
- * hook is called with a clone of the packet. That code inserts
- * the packet into the receive queue of the packet socket.
- * If a filter is attached to that socket that filter is run
- * first - and there lies the problem. The default filter always
- * cuts the packet at the snaplen:
- *
- * # tcpdump -d
- * (000) ret #68
- *
- * So the packet filter cuts down the packet. The recvfrom call
- * says "hey, it's only 68 bytes, it fits into the buffer" with
- * the result that we don't get the real packet length. This
- * is valid at least until kernel 2.2.17pre6.
- *
- * We currently handle this by making a copy of the filter
- * program, fixing all "ret" instructions with non-zero
- * operands to have an operand of MAXIMUM_SNAPLEN so that the
- * filter doesn't truncate the packet, and supplying that modified
- * filter to the kernel.
- */
- caplen = packet_len;
- if (caplen > handle->snapshot)
- caplen = handle->snapshot;
- /* Run the packet filter if not using kernel filter */
- if (handlep->filter_in_userland && handle->fcode.bf_insns) {
- if (bpf_filter_with_aux_data(handle->fcode.bf_insns, bp,
- packet_len, caplen, &aux_data) == 0) {
- /* rejected by filter */
- return 0;
- }
- }
- /* Fill in our own header data */
- /* get timestamp for this packet */
- #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
- if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
- if (ioctl(handle->fd, SIOCGSTAMPNS, &pcap_header.ts) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SIOCGSTAMPNS: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- } else
- #endif
- {
- if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SIOCGSTAMP: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- }
- pcap_header.caplen = caplen;
- pcap_header.len = packet_len;
- /*
- * Count the packet.
- *
- * Arguably, we should count them before we check the filter,
- * as on many other platforms "ps_recv" counts packets
- * handed to the filter rather than packets that passed
- * the filter, but if filtering is done in the kernel, we
- * can't get a count of packets that passed the filter,
- * and that would mean the meaning of "ps_recv" wouldn't
- * be the same on all Linux systems.
- *
- * XXX - it's not the same on all systems in any case;
- * ideally, we should have a "get the statistics" call
- * that supplies more counts and indicates which of them
- * it supplies, so that we supply a count of packets
- * handed to the filter only on platforms where that
- * information is available.
- *
- * We count them here even if we can get the packet count
- * from the kernel, as we can only determine at run time
- * whether we'll be able to get it from the kernel (if
- * HAVE_TPACKET_STATS isn't defined, we can't get it from
- * the kernel, but if it is defined, the library might
- * have been built with a 2.4 or later kernel, but we
- * might be running on a 2.2[.x] kernel without Alexey
- * Kuznetzov's turbopacket patches, and thus the kernel
- * might not be able to supply those statistics). We
- * could, I guess, try, when opening the socket, to get
- * the statistics, and if we can not increment the count
- * here, but it's not clear that always incrementing
- * the count is more expensive than always testing a flag
- * in memory.
- *
- * We keep the count in "handlep->packets_read", and use that
- * for "ps_recv" if we can't get the statistics from the kernel.
- * We do that because, if we *can* get the statistics from
- * the kernel, we use "handlep->stat.ps_recv" and
- * "handlep->stat.ps_drop" as running counts, as reading the
- * statistics from the kernel resets the kernel statistics,
- * and if we directly increment "handlep->stat.ps_recv" here,
- * that means it will count packets *twice* on systems where
- * we can get kernel statistics - once here, and once in
- * pcap_stats_linux().
- */
- handlep->packets_read++;
- /* Call the user supplied callback function */
- callback(userdata, &pcap_header, bp);
- return 1;
- }
- static int
- pcap_inject_linux(pcap_t *handle, const void *buf, size_t size)
- {
- struct pcap_linux *handlep = handle->priv;
- int ret;
- #ifdef HAVE_PF_PACKET_SOCKETS
- if (!handlep->sock_packet) {
- /* PF_PACKET socket */
- if (handlep->ifindex == -1) {
- /*
- * We don't support sending on the "any" device.
- */
- strlcpy(handle->errbuf,
- "Sending packets isn't supported on the \"any\" device",
- PCAP_ERRBUF_SIZE);
- return (-1);
- }
- if (handlep->cooked) {
- /*
- * We don't support sending on the "any" device.
- *
- * XXX - how do you send on a bound cooked-mode
- * socket?
- * Is a "sendto()" required there?
- */
- strlcpy(handle->errbuf,
- "Sending packets isn't supported in cooked mode",
- PCAP_ERRBUF_SIZE);
- return (-1);
- }
- }
- #endif
- ret = send(handle->fd, buf, size, 0);
- if (ret == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
- pcap_strerror(errno));
- return (-1);
- }
- return (ret);
- }
- /*
- * Get the statistics for the given packet capture handle.
- * Reports the number of dropped packets iff the kernel supports
- * the PACKET_STATISTICS "getsockopt()" argument (2.4 and later
- * kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket
- * patches); otherwise, that information isn't available, and we lie
- * and report 0 as the count of dropped packets.
- */
- static int
- pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
- {
- struct pcap_linux *handlep = handle->priv;
- #ifdef HAVE_TPACKET_STATS
- #ifdef HAVE_TPACKET3
- /*
- * For sockets using TPACKET_V1 or TPACKET_V2, the extra
- * stuff at the end of a struct tpacket_stats_v3 will not
- * be filled in, and we don't look at it so this is OK even
- * for those sockets. In addition, the PF_PACKET socket
- * code in the kernel only uses the length parameter to
- * compute how much data to copy out and to indicate how
- * much data was copied out, so it's OK to base it on the
- * size of a struct tpacket_stats.
- *
- * XXX - it's probably OK, in fact, to just use a
- * struct tpacket_stats for V3 sockets, as we don't
- * care about the tp_freeze_q_cnt stat.
- */
- struct tpacket_stats_v3 kstats;
- #else /* HAVE_TPACKET3 */
- struct tpacket_stats kstats;
- #endif /* HAVE_TPACKET3 */
- socklen_t len = sizeof (struct tpacket_stats);
- #endif /* HAVE_TPACKET_STATS */
- long if_dropped = 0;
- /*
- * To fill in ps_ifdrop, we parse /proc/net/dev for the number
- */
- if (handle->opt.promisc)
- {
- if_dropped = handlep->proc_dropped;
- handlep->proc_dropped = linux_if_drops(handlep->device);
- handlep->stat.ps_ifdrop += (handlep->proc_dropped - if_dropped);
- }
- #ifdef HAVE_TPACKET_STATS
- /*
- * Try to get the packet counts from the kernel.
- */
- if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
- &kstats, &len) > -1) {
- /*
- * On systems where the PACKET_STATISTICS "getsockopt()"
- * argument is supported on PF_PACKET sockets:
- *
- * "ps_recv" counts only packets that *passed* the
- * filter, not packets that didn't pass the filter.
- * This includes packets later dropped because we
- * ran out of buffer space.
- *
- * "ps_drop" counts packets dropped because we ran
- * out of buffer space. It doesn't count packets
- * dropped by the interface driver. It counts only
- * packets that passed the filter.
- *
- * See above for ps_ifdrop.
- *
- * Both statistics include packets not yet read from
- * the kernel by libpcap, and thus not yet seen by
- * the application.
- *
- * In "linux/net/packet/af_packet.c", at least in the
- * 2.4.9 kernel, "tp_packets" is incremented for every
- * packet that passes the packet filter *and* is
- * successfully queued on the socket; "tp_drops" is
- * incremented for every packet dropped because there's
- * not enough free space in the socket buffer.
- *
- * When the statistics are returned for a PACKET_STATISTICS
- * "getsockopt()" call, "tp_drops" is added to "tp_packets",
- * so that "tp_packets" counts all packets handed to
- * the PF_PACKET socket, including packets dropped because
- * there wasn't room on the socket buffer - but not
- * including packets that didn't pass the filter.
- *
- * In the BSD BPF, the count of received packets is
- * incremented for every packet handed to BPF, regardless
- * of whether it passed the filter.
- *
- * We can't make "pcap_stats()" work the same on both
- * platforms, but the best approximation is to return
- * "tp_packets" as the count of packets and "tp_drops"
- * as the count of drops.
- *
- * Keep a running total because each call to
- * getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, ....
- * resets the counters to zero.
- */
- handlep->stat.ps_recv += kstats.tp_packets;
- handlep->stat.ps_drop += kstats.tp_drops;
- *stats = handlep->stat;
- return 0;
- }
- else
- {
- /*
- * If the error was EOPNOTSUPP, fall through, so that
- * if you build the library on a system with
- * "struct tpacket_stats" and run it on a system
- * that doesn't, it works as it does if the library
- * is built on a system without "struct tpacket_stats".
- */
- if (errno != EOPNOTSUPP) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "pcap_stats: %s", pcap_strerror(errno));
- return -1;
- }
- }
- #endif
- /*
- * On systems where the PACKET_STATISTICS "getsockopt()" argument
- * is not supported on PF_PACKET sockets:
- *
- * "ps_recv" counts only packets that *passed* the filter,
- * not packets that didn't pass the filter. It does not
- * count packets dropped because we ran out of buffer
- * space.
- *
- * "ps_drop" is not supported.
- *
- * "ps_ifdrop" is supported. It will return the number
- * of drops the interface reports in /proc/net/dev,
- * if that is available.
- *
- * "ps_recv" doesn't include packets not yet read from
- * the kernel by libpcap.
- *
- * We maintain the count of packets processed by libpcap in
- * "handlep->packets_read", for reasons described in the comment
- * at the end of pcap_read_packet(). We have no idea how many
- * packets were dropped by the kernel buffers -- but we know
- * how many the interface dropped, so we can return that.
- */
- stats->ps_recv = handlep->packets_read;
- stats->ps_drop = 0;
- stats->ps_ifdrop = handlep->stat.ps_ifdrop;
- return 0;
- }
- static int
- add_linux_if(pcap_if_t **devlistp, const char *ifname, int fd, char *errbuf)
- {
- const char *p;
- char name[512]; /* XXX - pick a size */
- char *q, *saveq;
- struct ifreq ifrflags;
- /*
- * Get the interface name.
- */
- p = ifname;
- q = &name[0];
- while (*p != '\0' && isascii(*p) && !isspace(*p)) {
- if (*p == ':') {
- /*
- * This could be the separator between a
- * name and an alias number, or it could be
- * the separator between a name with no
- * alias number and the next field.
- *
- * If there's a colon after digits, it
- * separates the name and the alias number,
- * otherwise it separates the name and the
- * next field.
- */
- saveq = q;
- while (isascii(*p) && isdigit(*p))
- *q++ = *p++;
- if (*p != ':') {
- /*
- * That was the next field,
- * not the alias number.
- */
- q = saveq;
- }
- break;
- } else
- *q++ = *p++;
- }
- *q = '\0';
- /*
- * Get the flags for this interface.
- */
- strlcpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
- if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
- if (errno == ENXIO || errno == ENODEV)
- return (0); /* device doesn't actually exist - ignore it */
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "SIOCGIFFLAGS: %.*s: %s",
- (int)sizeof(ifrflags.ifr_name),
- ifrflags.ifr_name,
- pcap_strerror(errno));
- return (-1);
- }
- /*
- * Add an entry for this interface, with no addresses.
- */
- if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
- errbuf) == -1) {
- /*
- * Failure.
- */
- return (-1);
- }
- return (0);
- }
- /*
- * Get from "/sys/class/net" all interfaces listed there; if they're
- * already in the list of interfaces we have, that won't add another
- * instance, but if they're not, that'll add them.
- *
- * We don't bother getting any addresses for them; it appears you can't
- * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
- * although some other types of addresses can be fetched with SIOCGIFADDR,
- * we don't bother with them for now.
- *
- * We also don't fail if we couldn't open "/sys/class/net"; we just leave
- * the list of interfaces as is, and return 0, so that we can try
- * scanning /proc/net/dev.
- *
- * Otherwise, we return 1 if we don't get an error and -1 if we do.
- */
- static int
- scan_sys_class_net(pcap_if_t **devlistp, char *errbuf)
- {
- DIR *sys_class_net_d;
- int fd;
- struct dirent *ent;
- char subsystem_path[PATH_MAX+1];
- struct stat statb;
- int ret = 1;
- sys_class_net_d = opendir("/sys/class/net");
- if (sys_class_net_d == NULL) {
- /*
- * Don't fail if it doesn't exist at all.
- */
- if (errno == ENOENT)
- return (0);
- /*
- * Fail if we got some other error.
- */
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "Can't open /sys/class/net: %s", pcap_strerror(errno));
- return (-1);
- }
- /*
- * Create a socket from which to fetch interface information.
- */
- fd = socket(AF_INET, SOCK_DGRAM, 0);
- if (fd < 0) {
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- (void)closedir(sys_class_net_d);
- return (-1);
- }
- for (;;) {
- errno = 0;
- ent = readdir(sys_class_net_d);
- if (ent == NULL) {
- /*
- * Error or EOF; if errno != 0, it's an error.
- */
- break;
- }
- /*
- * Ignore "." and "..".
- */
- if (strcmp(ent->d_name, ".") == 0 ||
- strcmp(ent->d_name, "..") == 0)
- continue;
- /*
- * Ignore plain files; they do not have subdirectories
- * and thus have no attributes.
- */
- if (ent->d_type == DT_REG)
- continue;
- /*
- * Is there an "ifindex" file under that name?
- * (We don't care whether it's a directory or
- * a symlink; older kernels have directories
- * for devices, newer kernels have symlinks to
- * directories.)
- */
- snprintf(subsystem_path, sizeof subsystem_path,
- "/sys/class/net/%s/ifindex", ent->d_name);
- if (lstat(subsystem_path, &statb) != 0) {
- /*
- * Stat failed. Either there was an error
- * other than ENOENT, and we don't know if
- * this is an interface, or it's ENOENT,
- * and either some part of "/sys/class/net/{if}"
- * disappeared, in which case it probably means
- * the interface disappeared, or there's no
- * "ifindex" file, which means it's not a
- * network interface.
- */
- continue;
- }
- /*
- * Attempt to add the interface.
- */
- if (add_linux_if(devlistp, &ent->d_name[0], fd, errbuf) == -1) {
- /* Fail. */
- ret = -1;
- break;
- }
- }
- if (ret != -1) {
- /*
- * Well, we didn't fail for any other reason; did we
- * fail due to an error reading the directory?
- */
- if (errno != 0) {
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "Error reading /sys/class/net: %s",
- pcap_strerror(errno));
- ret = -1;
- }
- }
- (void)close(fd);
- (void)closedir(sys_class_net_d);
- return (ret);
- }
- /*
- * Get from "/proc/net/dev" all interfaces listed there; if they're
- * already in the list of interfaces we have, that won't add another
- * instance, but if they're not, that'll add them.
- *
- * See comments from scan_sys_class_net().
- */
- static int
- scan_proc_net_dev(pcap_if_t **devlistp, char *errbuf)
- {
- FILE *proc_net_f;
- int fd;
- char linebuf[512];
- int linenum;
- char *p;
- int ret = 0;
- proc_net_f = fopen("/proc/net/dev", "r");
- if (proc_net_f == NULL) {
- /*
- * Don't fail if it doesn't exist at all.
- */
- if (errno == ENOENT)
- return (0);
- /*
- * Fail if we got some other error.
- */
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "Can't open /proc/net/dev: %s", pcap_strerror(errno));
- return (-1);
- }
- /*
- * Create a socket from which to fetch interface information.
- */
- fd = socket(AF_INET, SOCK_DGRAM, 0);
- if (fd < 0) {
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- (void)fclose(proc_net_f);
- return (-1);
- }
- for (linenum = 1;
- fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
- /*
- * Skip the first two lines - they're headers.
- */
- if (linenum <= 2)
- continue;
- p = &linebuf[0];
- /*
- * Skip leading white space.
- */
- while (*p != '\0' && isascii(*p) && isspace(*p))
- p++;
- if (*p == '\0' || *p == '\n')
- continue; /* blank line */
- /*
- * Attempt to add the interface.
- */
- if (add_linux_if(devlistp, p, fd, errbuf) == -1) {
- /* Fail. */
- ret = -1;
- break;
- }
- }
- if (ret != -1) {
- /*
- * Well, we didn't fail for any other reason; did we
- * fail due to an error reading the file?
- */
- if (ferror(proc_net_f)) {
- (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
- "Error reading /proc/net/dev: %s",
- pcap_strerror(errno));
- ret = -1;
- }
- }
- (void)close(fd);
- (void)fclose(proc_net_f);
- return (ret);
- }
- /*
- * Description string for the "any" device.
- */
- static const char any_descr[] = "Pseudo-device that captures on all interfaces";
- int
- pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
- {
- int ret;
- /*
- * Read "/sys/class/net", and add to the list of interfaces all
- * interfaces listed there that we don't already have, because,
- * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
- * and even getifaddrs() won't return information about
- * interfaces with no addresses, so you need to read "/sys/class/net"
- * to get the names of the rest of the interfaces.
- */
- ret = scan_sys_class_net(alldevsp, errbuf);
- if (ret == -1)
- return (-1); /* failed */
- if (ret == 0) {
- /*
- * No /sys/class/net; try reading /proc/net/dev instead.
- */
- if (scan_proc_net_dev(alldevsp, errbuf) == -1)
- return (-1);
- }
- /*
- * Add the "any" device.
- */
- if (pcap_add_if(alldevsp, "any", IFF_UP|IFF_RUNNING,
- any_descr, errbuf) < 0)
- return (-1);
- return (0);
- }
- /*
- * Attach the given BPF code to the packet capture device.
- */
- static int
- pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter,
- int is_mmapped)
- {
- struct pcap_linux *handlep;
- #ifdef SO_ATTACH_FILTER
- struct sock_fprog fcode;
- int can_filter_in_kernel;
- int err = 0;
- #endif
- if (!handle)
- return -1;
- if (!filter) {
- strlcpy(handle->errbuf, "setfilter: No filter specified",
- PCAP_ERRBUF_SIZE);
- return -1;
- }
- handlep = handle->priv;
- /* Make our private copy of the filter */
- if (install_bpf_program(handle, filter) < 0)
- /* install_bpf_program() filled in errbuf */
- return -1;
- /*
- * Run user level packet filter by default. Will be overriden if
- * installing a kernel filter succeeds.
- */
- handlep->filter_in_userland = 1;
- /* Install kernel level filter if possible */
- #ifdef SO_ATTACH_FILTER
- #ifdef USHRT_MAX
- if (handle->fcode.bf_len > USHRT_MAX) {
- /*
- * fcode.len is an unsigned short for current kernel.
- * I have yet to see BPF-Code with that much
- * instructions but still it is possible. So for the
- * sake of correctness I added this check.
- */
- fprintf(stderr, "Warning: Filter too complex for kernel\n");
- fcode.len = 0;
- fcode.filter = NULL;
- can_filter_in_kernel = 0;
- } else
- #endif /* USHRT_MAX */
- {
- /*
- * Oh joy, the Linux kernel uses struct sock_fprog instead
- * of struct bpf_program and of course the length field is
- * of different size. Pointed out by Sebastian
- *
- * Oh, and we also need to fix it up so that all "ret"
- * instructions with non-zero operands have MAXIMUM_SNAPLEN
- * as the operand if we're not capturing in memory-mapped
- * mode, and so that, if we're in cooked mode, all memory-
- * reference instructions use special magic offsets in
- * references to the link-layer header and assume that the
- * link-layer payload begins at 0; "fix_program()" will do
- * that.
- */
- switch (fix_program(handle, &fcode, is_mmapped)) {
- case -1:
- default:
- /*
- * Fatal error; just quit.
- * (The "default" case shouldn't happen; we
- * return -1 for that reason.)
- */
- return -1;
- case 0:
- /*
- * The program performed checks that we can't make
- * work in the kernel.
- */
- can_filter_in_kernel = 0;
- break;
- case 1:
- /*
- * We have a filter that'll work in the kernel.
- */
- can_filter_in_kernel = 1;
- break;
- }
- }
- /*
- * NOTE: at this point, we've set both the "len" and "filter"
- * fields of "fcode". As of the 2.6.32.4 kernel, at least,
- * those are the only members of the "sock_fprog" structure,
- * so we initialize every member of that structure.
- *
- * If there is anything in "fcode" that is not initialized,
- * it is either a field added in a later kernel, or it's
- * padding.
- *
- * If a new field is added, this code needs to be updated
- * to set it correctly.
- *
- * If there are no other fields, then:
- *
- * if the Linux kernel looks at the padding, it's
- * buggy;
- *
- * if the Linux kernel doesn't look at the padding,
- * then if some tool complains that we're passing
- * uninitialized data to the kernel, then the tool
- * is buggy and needs to understand that it's just
- * padding.
- */
- if (can_filter_in_kernel) {
- if ((err = set_kernel_filter(handle, &fcode)) == 0)
- {
- /*
- * Installation succeded - using kernel filter,
- * so userland filtering not needed.
- */
- handlep->filter_in_userland = 0;
- }
- else if (err == -1) /* Non-fatal error */
- {
- /*
- * Print a warning if we weren't able to install
- * the filter for a reason other than "this kernel
- * isn't configured to support socket filters.
- */
- if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) {
- fprintf(stderr,
- "Warning: Kernel filter failed: %s\n",
- pcap_strerror(errno));
- }
- }
- }
- /*
- * If we're not using the kernel filter, get rid of any kernel
- * filter that might've been there before, e.g. because the
- * previous filter could work in the kernel, or because some other
- * code attached a filter to the socket by some means other than
- * calling "pcap_setfilter()". Otherwise, the kernel filter may
- * filter out packets that would pass the new userland filter.
- */
- if (handlep->filter_in_userland) {
- if (reset_kernel_filter(handle) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't remove kernel filter: %s",
- pcap_strerror(errno));
- err = -2; /* fatal error */
- }
- }
- /*
- * Free up the copy of the filter that was made by "fix_program()".
- */
- if (fcode.filter != NULL)
- free(fcode.filter);
- if (err == -2)
- /* Fatal error */
- return -1;
- #endif /* SO_ATTACH_FILTER */
- return 0;
- }
- static int
- pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
- {
- return pcap_setfilter_linux_common(handle, filter, 0);
- }
- /*
- * Set direction flag: Which packets do we accept on a forwarding
- * single device? IN, OUT or both?
- */
- static int
- pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d)
- {
- #ifdef HAVE_PF_PACKET_SOCKETS
- struct pcap_linux *handlep = handle->priv;
- if (!handlep->sock_packet) {
- handle->direction = d;
- return 0;
- }
- #endif
- /*
- * We're not using PF_PACKET sockets, so we can't determine
- * the direction of the packet.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "Setting direction is not supported on SOCK_PACKET sockets");
- return -1;
- }
- #ifdef HAVE_PF_PACKET_SOCKETS
- /*
- * Map the PACKET_ value to a LINUX_SLL_ value; we
- * want the same numerical value to be used in
- * the link-layer header even if the numerical values
- * for the PACKET_ #defines change, so that programs
- * that look at the packet type field will always be
- * able to handle DLT_LINUX_SLL captures.
- */
- static short int
- map_packet_type_to_sll_type(short int sll_pkttype)
- {
- switch (sll_pkttype) {
- case PACKET_HOST:
- return htons(LINUX_SLL_HOST);
- case PACKET_BROADCAST:
- return htons(LINUX_SLL_BROADCAST);
- case PACKET_MULTICAST:
- return htons(LINUX_SLL_MULTICAST);
- case PACKET_OTHERHOST:
- return htons(LINUX_SLL_OTHERHOST);
- case PACKET_OUTGOING:
- return htons(LINUX_SLL_OUTGOING);
- default:
- return -1;
- }
- }
- #endif
- static int
- is_wifi(int sock_fd
- #ifndef IW_MODE_MONITOR
- _U_
- #endif
- , const char *device)
- {
- char *pathstr;
- struct stat statb;
- #ifdef IW_MODE_MONITOR
- char errbuf[PCAP_ERRBUF_SIZE];
- #endif
- /*
- * See if there's a sysfs wireless directory for it.
- * If so, it's a wireless interface.
- */
- if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) {
- /*
- * Just give up here.
- */
- return 0;
- }
- if (stat(pathstr, &statb) == 0) {
- free(pathstr);
- return 1;
- }
- free(pathstr);
- #ifdef IW_MODE_MONITOR
- /*
- * OK, maybe it's not wireless, or maybe this kernel doesn't
- * support sysfs. Try the wireless extensions.
- */
- if (has_wext(sock_fd, device, errbuf) == 1) {
- /*
- * It supports the wireless extensions, so it's a Wi-Fi
- * device.
- */
- return 1;
- }
- #endif
- return 0;
- }
- /*
- * Linux uses the ARP hardware type to identify the type of an
- * interface. pcap uses the DLT_xxx constants for this. This
- * function takes a pointer to a "pcap_t", and an ARPHRD_xxx
- * constant, as arguments, and sets "handle->linktype" to the
- * appropriate DLT_XXX constant and sets "handle->offset" to
- * the appropriate value (to make "handle->offset" plus link-layer
- * header length be a multiple of 4, so that the link-layer payload
- * will be aligned on a 4-byte boundary when capturing packets).
- * (If the offset isn't set here, it'll be 0; add code as appropriate
- * for cases where it shouldn't be 0.)
- *
- * If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture
- * in cooked mode; otherwise, we can't use cooked mode, so we have
- * to pick some type that works in raw mode, or fail.
- *
- * Sets the link type to -1 if unable to map the type.
- */
- static void map_arphrd_to_dlt(pcap_t *handle, int sock_fd, int arptype,
- const char *device, int cooked_ok)
- {
- static const char cdma_rmnet[] = "cdma_rmnet";
- switch (arptype) {
- case ARPHRD_ETHER:
- /*
- * For various annoying reasons having to do with DHCP
- * software, some versions of Android give the mobile-
- * phone-network interface an ARPHRD_ value of
- * ARPHRD_ETHER, even though the packets supplied by
- * that interface have no link-layer header, and begin
- * with an IP header, so that the ARPHRD_ value should
- * be ARPHRD_NONE.
- *
- * Detect those devices by checking the device name, and
- * use DLT_RAW for them.
- */
- if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) {
- handle->linktype = DLT_RAW;
- return;
- }
- /*
- * Is this a real Ethernet device? If so, give it a
- * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
- * that an application can let you choose it, in case you're
- * capturing DOCSIS traffic that a Cisco Cable Modem
- * Termination System is putting out onto an Ethernet (it
- * doesn't put an Ethernet header onto the wire, it puts raw
- * DOCSIS frames out on the wire inside the low-level
- * Ethernet framing).
- *
- * XXX - are there any other sorts of "fake Ethernet" that
- * have ARPHRD_ETHER but that shouldn't offer DLT_DOCSIS as
- * a Cisco CMTS won't put traffic onto it or get traffic
- * bridged onto it? ISDN is handled in "activate_new()",
- * as we fall back on cooked mode there, and we use
- * is_wifi() to check for 802.11 devices; are there any
- * others?
- */
- if (!is_wifi(sock_fd, device)) {
- /*
- * It's not a Wi-Fi device; offer DOCSIS.
- */
- handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
- /*
- * If that fails, just leave the list empty.
- */
- if (handle->dlt_list != NULL) {
- handle->dlt_list[0] = DLT_EN10MB;
- handle->dlt_list[1] = DLT_DOCSIS;
- handle->dlt_count = 2;
- }
- }
- /* FALLTHROUGH */
- case ARPHRD_METRICOM:
- case ARPHRD_LOOPBACK:
- handle->linktype = DLT_EN10MB;
- handle->offset = 2;
- break;
- case ARPHRD_EETHER:
- handle->linktype = DLT_EN3MB;
- break;
- case ARPHRD_AX25:
- handle->linktype = DLT_AX25_KISS;
- break;
- case ARPHRD_PRONET:
- handle->linktype = DLT_PRONET;
- break;
- case ARPHRD_CHAOS:
- handle->linktype = DLT_CHAOS;
- break;
- #ifndef ARPHRD_CAN
- #define ARPHRD_CAN 280
- #endif
- case ARPHRD_CAN:
- handle->linktype = DLT_CAN_SOCKETCAN;
- break;
- #ifndef ARPHRD_IEEE802_TR
- #define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */
- #endif
- case ARPHRD_IEEE802_TR:
- case ARPHRD_IEEE802:
- handle->linktype = DLT_IEEE802;
- handle->offset = 2;
- break;
- case ARPHRD_ARCNET:
- handle->linktype = DLT_ARCNET_LINUX;
- break;
- #ifndef ARPHRD_FDDI /* From Linux 2.2.13 */
- #define ARPHRD_FDDI 774
- #endif
- case ARPHRD_FDDI:
- handle->linktype = DLT_FDDI;
- handle->offset = 3;
- break;
- #ifndef ARPHRD_ATM /* FIXME: How to #include this? */
- #define ARPHRD_ATM 19
- #endif
- case ARPHRD_ATM:
- /*
- * The Classical IP implementation in ATM for Linux
- * supports both what RFC 1483 calls "LLC Encapsulation",
- * in which each packet has an LLC header, possibly
- * with a SNAP header as well, prepended to it, and
- * what RFC 1483 calls "VC Based Multiplexing", in which
- * different virtual circuits carry different network
- * layer protocols, and no header is prepended to packets.
- *
- * They both have an ARPHRD_ type of ARPHRD_ATM, so
- * you can't use the ARPHRD_ type to find out whether
- * captured packets will have an LLC header, and,
- * while there's a socket ioctl to *set* the encapsulation
- * type, there's no ioctl to *get* the encapsulation type.
- *
- * This means that
- *
- * programs that dissect Linux Classical IP frames
- * would have to check for an LLC header and,
- * depending on whether they see one or not, dissect
- * the frame as LLC-encapsulated or as raw IP (I
- * don't know whether there's any traffic other than
- * IP that would show up on the socket, or whether
- * there's any support for IPv6 in the Linux
- * Classical IP code);
- *
- * filter expressions would have to compile into
- * code that checks for an LLC header and does
- * the right thing.
- *
- * Both of those are a nuisance - and, at least on systems
- * that support PF_PACKET sockets, we don't have to put
- * up with those nuisances; instead, we can just capture
- * in cooked mode. That's what we'll do, if we can.
- * Otherwise, we'll just fail.
- */
- if (cooked_ok)
- handle->linktype = DLT_LINUX_SLL;
- else
- handle->linktype = -1;
- break;
- #ifndef ARPHRD_IEEE80211 /* From Linux 2.4.6 */
- #define ARPHRD_IEEE80211 801
- #endif
- case ARPHRD_IEEE80211:
- handle->linktype = DLT_IEEE802_11;
- break;
- #ifndef ARPHRD_IEEE80211_PRISM /* From Linux 2.4.18 */
- #define ARPHRD_IEEE80211_PRISM 802
- #endif
- case ARPHRD_IEEE80211_PRISM:
- handle->linktype = DLT_PRISM_HEADER;
- break;
- #ifndef ARPHRD_IEEE80211_RADIOTAP /* new */
- #define ARPHRD_IEEE80211_RADIOTAP 803
- #endif
- case ARPHRD_IEEE80211_RADIOTAP:
- handle->linktype = DLT_IEEE802_11_RADIO;
- break;
- case ARPHRD_PPP:
- /*
- * Some PPP code in the kernel supplies no link-layer
- * header whatsoever to PF_PACKET sockets; other PPP
- * code supplies PPP link-layer headers ("syncppp.c");
- * some PPP code might supply random link-layer
- * headers (PPP over ISDN - there's code in Ethereal,
- * for example, to cope with PPP-over-ISDN captures
- * with which the Ethereal developers have had to cope,
- * heuristically trying to determine which of the
- * oddball link-layer headers particular packets have).
- *
- * As such, we just punt, and run all PPP interfaces
- * in cooked mode, if we can; otherwise, we just treat
- * it as DLT_RAW, for now - if somebody needs to capture,
- * on a 2.0[.x] kernel, on PPP devices that supply a
- * link-layer header, they'll have to add code here to
- * map to the appropriate DLT_ type (possibly adding a
- * new DLT_ type, if necessary).
- */
- if (cooked_ok)
- handle->linktype = DLT_LINUX_SLL;
- else {
- /*
- * XXX - handle ISDN types here? We can't fall
- * back on cooked sockets, so we'd have to
- * figure out from the device name what type of
- * link-layer encapsulation it's using, and map
- * that to an appropriate DLT_ value, meaning
- * we'd map "isdnN" devices to DLT_RAW (they
- * supply raw IP packets with no link-layer
- * header) and "isdY" devices to a new DLT_I4L_IP
- * type that has only an Ethernet packet type as
- * a link-layer header.
- *
- * But sometimes we seem to get random crap
- * in the link-layer header when capturing on
- * ISDN devices....
- */
- handle->linktype = DLT_RAW;
- }
- break;
- #ifndef ARPHRD_CISCO
- #define ARPHRD_CISCO 513 /* previously ARPHRD_HDLC */
- #endif
- case ARPHRD_CISCO:
- handle->linktype = DLT_C_HDLC;
- break;
- /* Not sure if this is correct for all tunnels, but it
- * works for CIPE */
- case ARPHRD_TUNNEL:
- #ifndef ARPHRD_SIT
- #define ARPHRD_SIT 776 /* From Linux 2.2.13 */
- #endif
- case ARPHRD_SIT:
- case ARPHRD_CSLIP:
- case ARPHRD_SLIP6:
- case ARPHRD_CSLIP6:
- case ARPHRD_ADAPT:
- case ARPHRD_SLIP:
- #ifndef ARPHRD_RAWHDLC
- #define ARPHRD_RAWHDLC 518
- #endif
- case ARPHRD_RAWHDLC:
- #ifndef ARPHRD_DLCI
- #define ARPHRD_DLCI 15
- #endif
- case ARPHRD_DLCI:
- /*
- * XXX - should some of those be mapped to DLT_LINUX_SLL
- * instead? Should we just map all of them to DLT_LINUX_SLL?
- */
- handle->linktype = DLT_RAW;
- break;
- #ifndef ARPHRD_FRAD
- #define ARPHRD_FRAD 770
- #endif
- case ARPHRD_FRAD:
- handle->linktype = DLT_FRELAY;
- break;
- case ARPHRD_LOCALTLK:
- handle->linktype = DLT_LTALK;
- break;
- case 18:
- /*
- * RFC 4338 defines an encapsulation for IP and ARP
- * packets that's compatible with the RFC 2625
- * encapsulation, but that uses a different ARP
- * hardware type and hardware addresses. That
- * ARP hardware type is 18; Linux doesn't define
- * any ARPHRD_ value as 18, but if it ever officially
- * supports RFC 4338-style IP-over-FC, it should define
- * one.
- *
- * For now, we map it to DLT_IP_OVER_FC, in the hopes
- * that this will encourage its use in the future,
- * should Linux ever officially support RFC 4338-style
- * IP-over-FC.
- */
- handle->linktype = DLT_IP_OVER_FC;
- break;
- #ifndef ARPHRD_FCPP
- #define ARPHRD_FCPP 784
- #endif
- case ARPHRD_FCPP:
- #ifndef ARPHRD_FCAL
- #define ARPHRD_FCAL 785
- #endif
- case ARPHRD_FCAL:
- #ifndef ARPHRD_FCPL
- #define ARPHRD_FCPL 786
- #endif
- case ARPHRD_FCPL:
- #ifndef ARPHRD_FCFABRIC
- #define ARPHRD_FCFABRIC 787
- #endif
- case ARPHRD_FCFABRIC:
- /*
- * Back in 2002, Donald Lee at Cray wanted a DLT_ for
- * IP-over-FC:
- *
- * http://www.mail-archive.com/tcpdump-workers@sandelman.ottawa.on.ca/msg01043.html
- *
- * and one was assigned.
- *
- * In a later private discussion (spun off from a message
- * on the ethereal-users list) on how to get that DLT_
- * value in libpcap on Linux, I ended up deciding that
- * the best thing to do would be to have him tweak the
- * driver to set the ARPHRD_ value to some ARPHRD_FCxx
- * type, and map all those types to DLT_IP_OVER_FC:
- *
- * I've checked into the libpcap and tcpdump CVS tree
- * support for DLT_IP_OVER_FC. In order to use that,
- * you'd have to modify your modified driver to return
- * one of the ARPHRD_FCxxx types, in "fcLINUXfcp.c" -
- * change it to set "dev->type" to ARPHRD_FCFABRIC, for
- * example (the exact value doesn't matter, it can be
- * any of ARPHRD_FCPP, ARPHRD_FCAL, ARPHRD_FCPL, or
- * ARPHRD_FCFABRIC).
- *
- * 11 years later, Christian Svensson wanted to map
- * various ARPHRD_ values to DLT_FC_2 and
- * DLT_FC_2_WITH_FRAME_DELIMS for raw Fibre Channel
- * frames:
- *
- * https://github.com/mcr/libpcap/pull/29
- *
- * There doesn't seem to be any network drivers that uses
- * any of the ARPHRD_FC* values for IP-over-FC, and
- * it's not exactly clear what the "Dummy types for non
- * ARP hardware" are supposed to mean (link-layer
- * header type? Physical network type?), so it's
- * not exactly clear why the ARPHRD_FC* types exist
- * in the first place.
- *
- * For now, we map them to DLT_FC_2, and provide an
- * option of DLT_FC_2_WITH_FRAME_DELIMS, as well as
- * DLT_IP_OVER_FC just in case there's some old
- * driver out there that uses one of those types for
- * IP-over-FC on which somebody wants to capture
- * packets.
- */
- handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
- /*
- * If that fails, just leave the list empty.
- */
- if (handle->dlt_list != NULL) {
- handle->dlt_list[0] = DLT_FC_2;
- handle->dlt_list[1] = DLT_FC_2_WITH_FRAME_DELIMS;
- handle->dlt_list[2] = DLT_IP_OVER_FC;
- handle->dlt_count = 3;
- }
- handle->linktype = DLT_FC_2;
- break;
- #ifndef ARPHRD_IRDA
- #define ARPHRD_IRDA 783
- #endif
- case ARPHRD_IRDA:
- /* Don't expect IP packet out of this interfaces... */
- handle->linktype = DLT_LINUX_IRDA;
- /* We need to save packet direction for IrDA decoding,
- * so let's use "Linux-cooked" mode. Jean II
- *
- * XXX - this is handled in activate_new(). */
- //handlep->cooked = 1;
- break;
- /* ARPHRD_LAPD is unofficial and randomly allocated, if reallocation
- * is needed, please report it to <daniele@orlandi.com> */
- #ifndef ARPHRD_LAPD
- #define ARPHRD_LAPD 8445
- #endif
- case ARPHRD_LAPD:
- /* Don't expect IP packet out of this interfaces... */
- handle->linktype = DLT_LINUX_LAPD;
- break;
- #ifndef ARPHRD_NONE
- #define ARPHRD_NONE 0xFFFE
- #endif
- case ARPHRD_NONE:
- /*
- * No link-layer header; packets are just IP
- * packets, so use DLT_RAW.
- */
- handle->linktype = DLT_RAW;
- break;
- #ifndef ARPHRD_IEEE802154
- #define ARPHRD_IEEE802154 804
- #endif
- case ARPHRD_IEEE802154:
- handle->linktype = DLT_IEEE802_15_4_NOFCS;
- break;
- #ifndef ARPHRD_NETLINK
- #define ARPHRD_NETLINK 824
- #endif
- case ARPHRD_NETLINK:
- handle->linktype = DLT_NETLINK;
- /*
- * We need to use cooked mode, so that in sll_protocol we
- * pick up the netlink protocol type such as NETLINK_ROUTE,
- * NETLINK_GENERIC, NETLINK_FIB_LOOKUP, etc.
- *
- * XXX - this is handled in activate_new().
- */
- //handlep->cooked = 1;
- break;
- default:
- handle->linktype = -1;
- break;
- }
- }
- /* ===== Functions to interface to the newer kernels ================== */
- /*
- * Try to open a packet socket using the new kernel PF_PACKET interface.
- * Returns 1 on success, 0 on an error that means the new interface isn't
- * present (so the old SOCK_PACKET interface should be tried), and a
- * PCAP_ERROR_ value on an error that means that the old mechanism won't
- * work either (so it shouldn't be tried).
- */
- static int
- activate_new(pcap_t *handle)
- {
- #ifdef HAVE_PF_PACKET_SOCKETS
- struct pcap_linux *handlep = handle->priv;
- const char *device = handle->opt.source;
- int is_any_device = (strcmp(device, "any") == 0);
- int sock_fd = -1, arptype;
- #ifdef HAVE_PACKET_AUXDATA
- int val;
- #endif
- int err = 0;
- struct packet_mreq mr;
- #ifdef SO_BPF_EXTENSIONS
- int bpf_extensions;
- socklen_t len = sizeof(bpf_extensions);
- #endif
- /*
- * Open a socket with protocol family packet. If the
- * "any" device was specified, we open a SOCK_DGRAM
- * socket for the cooked interface, otherwise we first
- * try a SOCK_RAW socket for the raw interface.
- */
- sock_fd = is_any_device ?
- socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL)) :
- socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
- if (sock_fd == -1) {
- if (errno == EINVAL || errno == EAFNOSUPPORT) {
- /*
- * We don't support PF_PACKET/SOCK_whatever
- * sockets; try the old mechanism.
- */
- return 0;
- }
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
- pcap_strerror(errno) );
- if (errno == EPERM || errno == EACCES) {
- /*
- * You don't have permission to open the
- * socket.
- */
- return PCAP_ERROR_PERM_DENIED;
- } else {
- /*
- * Other error.
- */
- return PCAP_ERROR;
- }
- }
- /* It seems the kernel supports the new interface. */
- handlep->sock_packet = 0;
- /*
- * Get the interface index of the loopback device.
- * If the attempt fails, don't fail, just set the
- * "handlep->lo_ifindex" to -1.
- *
- * XXX - can there be more than one device that loops
- * packets back, i.e. devices other than "lo"? If so,
- * we'd need to find them all, and have an array of
- * indices for them, and check all of them in
- * "pcap_read_packet()".
- */
- handlep->lo_ifindex = iface_get_id(sock_fd, "lo", handle->errbuf);
- /*
- * Default value for offset to align link-layer payload
- * on a 4-byte boundary.
- */
- handle->offset = 0;
- /*
- * What kind of frames do we have to deal with? Fall back
- * to cooked mode if we have an unknown interface type
- * or a type we know doesn't work well in raw mode.
- */
- if (!is_any_device) {
- /* Assume for now we don't need cooked mode. */
- handlep->cooked = 0;
- if (handle->opt.rfmon) {
- /*
- * We were asked to turn on monitor mode.
- * Do so before we get the link-layer type,
- * because entering monitor mode could change
- * the link-layer type.
- */
- err = enter_rfmon_mode(handle, sock_fd, device);
- if (err < 0) {
- /* Hard failure */
- close(sock_fd);
- return err;
- }
- if (err == 0) {
- /*
- * Nothing worked for turning monitor mode
- * on.
- */
- close(sock_fd);
- return PCAP_ERROR_RFMON_NOTSUP;
- }
- /*
- * Either monitor mode has been turned on for
- * the device, or we've been given a different
- * device to open for monitor mode. If we've
- * been given a different device, use it.
- */
- if (handlep->mondevice != NULL)
- device = handlep->mondevice;
- }
- arptype = iface_get_arptype(sock_fd, device, handle->errbuf);
- if (arptype < 0) {
- close(sock_fd);
- return arptype;
- }
- map_arphrd_to_dlt(handle, sock_fd, arptype, device, 1);
- if (handle->linktype == -1 ||
- handle->linktype == DLT_LINUX_SLL ||
- handle->linktype == DLT_LINUX_IRDA ||
- handle->linktype == DLT_LINUX_LAPD ||
- handle->linktype == DLT_NETLINK ||
- (handle->linktype == DLT_EN10MB &&
- (strncmp("isdn", device, 4) == 0 ||
- strncmp("isdY", device, 4) == 0))) {
- /*
- * Unknown interface type (-1), or a
- * device we explicitly chose to run
- * in cooked mode (e.g., PPP devices),
- * or an ISDN device (whose link-layer
- * type we can only determine by using
- * APIs that may be different on different
- * kernels) - reopen in cooked mode.
- */
- if (close(sock_fd) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "close: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- sock_fd = socket(PF_PACKET, SOCK_DGRAM,
- htons(ETH_P_ALL));
- if (sock_fd == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- if (errno == EPERM || errno == EACCES) {
- /*
- * You don't have permission to
- * open the socket.
- */
- return PCAP_ERROR_PERM_DENIED;
- } else {
- /*
- * Other error.
- */
- return PCAP_ERROR;
- }
- }
- handlep->cooked = 1;
- /*
- * Get rid of any link-layer type list
- * we allocated - this only supports cooked
- * capture.
- */
- if (handle->dlt_list != NULL) {
- free(handle->dlt_list);
- handle->dlt_list = NULL;
- handle->dlt_count = 0;
- }
- if (handle->linktype == -1) {
- /*
- * Warn that we're falling back on
- * cooked mode; we may want to
- * update "map_arphrd_to_dlt()"
- * to handle the new type.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "arptype %d not "
- "supported by libpcap - "
- "falling back to cooked "
- "socket",
- arptype);
- }
- /*
- * IrDA capture is not a real "cooked" capture,
- * it's IrLAP frames, not IP packets. The
- * same applies to LAPD capture.
- */
- if (handle->linktype != DLT_LINUX_IRDA &&
- handle->linktype != DLT_LINUX_LAPD &&
- handle->linktype != DLT_NETLINK)
- handle->linktype = DLT_LINUX_SLL;
- }
- handlep->ifindex = iface_get_id(sock_fd, device,
- handle->errbuf);
- if (handlep->ifindex == -1) {
- close(sock_fd);
- return PCAP_ERROR;
- }
- if ((err = iface_bind(sock_fd, handlep->ifindex,
- handle->errbuf)) != 1) {
- close(sock_fd);
- if (err < 0)
- return err;
- else
- return 0; /* try old mechanism */
- }
- } else {
- /*
- * The "any" device.
- */
- if (handle->opt.rfmon) {
- /*
- * It doesn't support monitor mode.
- */
- close(sock_fd);
- return PCAP_ERROR_RFMON_NOTSUP;
- }
- /*
- * It uses cooked mode.
- */
- handlep->cooked = 1;
- handle->linktype = DLT_LINUX_SLL;
- /*
- * We're not bound to a device.
- * For now, we're using this as an indication
- * that we can't transmit; stop doing that only
- * if we figure out how to transmit in cooked
- * mode.
- */
- handlep->ifindex = -1;
- }
- /*
- * Select promiscuous mode on if "promisc" is set.
- *
- * Do not turn allmulti mode on if we don't select
- * promiscuous mode - on some devices (e.g., Orinoco
- * wireless interfaces), allmulti mode isn't supported
- * and the driver implements it by turning promiscuous
- * mode on, and that screws up the operation of the
- * card as a normal networking interface, and on no
- * other platform I know of does starting a non-
- * promiscuous capture affect which multicast packets
- * are received by the interface.
- */
- /*
- * Hmm, how can we set promiscuous mode on all interfaces?
- * I am not sure if that is possible at all. For now, we
- * silently ignore attempts to turn promiscuous mode on
- * for the "any" device (so you don't have to explicitly
- * disable it in programs such as tcpdump).
- */
- if (!is_any_device && handle->opt.promisc) {
- memset(&mr, 0, sizeof(mr));
- mr.mr_ifindex = handlep->ifindex;
- mr.mr_type = PACKET_MR_PROMISC;
- if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP,
- &mr, sizeof(mr)) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "setsockopt: %s", pcap_strerror(errno));
- close(sock_fd);
- return PCAP_ERROR;
- }
- }
- /* Enable auxillary data if supported and reserve room for
- * reconstructing VLAN headers. */
- #ifdef HAVE_PACKET_AUXDATA
- val = 1;
- if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val,
- sizeof(val)) == -1 && errno != ENOPROTOOPT) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "setsockopt: %s", pcap_strerror(errno));
- close(sock_fd);
- return PCAP_ERROR;
- }
- handle->offset += VLAN_TAG_LEN;
- #endif /* HAVE_PACKET_AUXDATA */
- /*
- * This is a 2.2[.x] or later kernel (we know that
- * because we're not using a SOCK_PACKET socket -
- * PF_PACKET is supported only in 2.2 and later
- * kernels).
- *
- * We can safely pass "recvfrom()" a byte count
- * based on the snapshot length.
- *
- * If we're in cooked mode, make the snapshot length
- * large enough to hold a "cooked mode" header plus
- * 1 byte of packet data (so we don't pass a byte
- * count of 0 to "recvfrom()").
- */
- if (handlep->cooked) {
- if (handle->snapshot < SLL_HDR_LEN + 1)
- handle->snapshot = SLL_HDR_LEN + 1;
- }
- handle->bufsize = handle->snapshot;
- /*
- * Set the offset at which to insert VLAN tags.
- */
- switch (handle->linktype) {
- case DLT_EN10MB:
- handlep->vlan_offset = 2 * ETH_ALEN;
- break;
- case DLT_LINUX_SLL:
- handlep->vlan_offset = 14;
- break;
- default:
- handlep->vlan_offset = -1; /* unknown */
- break;
- }
- #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
- if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
- int nsec_tstamps = 1;
- if (setsockopt(sock_fd, SOL_SOCKET, SO_TIMESTAMPNS, &nsec_tstamps, sizeof(nsec_tstamps)) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "setsockopt: unable to set SO_TIMESTAMPNS");
- close(sock_fd);
- return PCAP_ERROR;
- }
- }
- #endif /* defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS) */
- /*
- * We've succeeded. Save the socket FD in the pcap structure.
- */
- handle->fd = sock_fd;
- #ifdef SO_BPF_EXTENSIONS
- /*
- * Can we generate special code for VLAN checks?
- * (XXX - what if we need the special code but it's not supported
- * by the OS? Is that possible?)
- */
- if (getsockopt(sock_fd, SOL_SOCKET, SO_BPF_EXTENSIONS,
- &bpf_extensions, &len) == 0) {
- if (bpf_extensions >= SKF_AD_VLAN_TAG_PRESENT) {
- /*
- * Yes, we can. Request that we do so.
- */
- handle->bpf_codegen_flags |= BPF_SPECIAL_VLAN_HANDLING;
- }
- }
- #endif /* SO_BPF_EXTENSIONS */
- return 1;
- #else /* HAVE_PF_PACKET_SOCKETS */
- strlcpy(ebuf,
- "New packet capturing interface not supported by build "
- "environment", PCAP_ERRBUF_SIZE);
- return 0;
- #endif /* HAVE_PF_PACKET_SOCKETS */
- }
- #ifdef HAVE_PACKET_RING
- /*
- * Attempt to activate with memory-mapped access.
- *
- * On success, returns 1, and sets *status to 0 if there are no warnings
- * or to a PCAP_WARNING_ code if there is a warning.
- *
- * On failure due to lack of support for memory-mapped capture, returns
- * 0.
- *
- * On error, returns -1, and sets *status to the appropriate error code;
- * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
- */
- static int
- activate_mmap(pcap_t *handle, int *status)
- {
- struct pcap_linux *handlep = handle->priv;
- int ret;
- /*
- * Attempt to allocate a buffer to hold the contents of one
- * packet, for use by the oneshot callback.
- */
- handlep->oneshot_buffer = malloc(handle->snapshot);
- if (handlep->oneshot_buffer == NULL) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't allocate oneshot buffer: %s",
- pcap_strerror(errno));
- *status = PCAP_ERROR;
- return -1;
- }
- if (handle->opt.buffer_size == 0) {
- /* by default request 2M for the ring buffer */
- handle->opt.buffer_size = 2*1024*1024;
- }
- ret = prepare_tpacket_socket(handle);
- if (ret == -1) {
- free(handlep->oneshot_buffer);
- *status = PCAP_ERROR;
- return ret;
- }
- ret = create_ring(handle, status);
- if (ret == 0) {
- /*
- * We don't support memory-mapped capture; our caller
- * will fall back on reading from the socket.
- */
- free(handlep->oneshot_buffer);
- return 0;
- }
- if (ret == -1) {
- /*
- * Error attempting to enable memory-mapped capture;
- * fail. create_ring() has set *status.
- */
- free(handlep->oneshot_buffer);
- return -1;
- }
- /*
- * Success. *status has been set either to 0 if there are no
- * warnings or to a PCAP_WARNING_ value if there is a warning.
- *
- * Override some defaults and inherit the other fields from
- * activate_new.
- * handle->offset is used to get the current position into the rx ring.
- * handle->cc is used to store the ring size.
- */
- switch (handlep->tp_version) {
- case TPACKET_V1:
- handle->read_op = pcap_read_linux_mmap_v1;
- break;
- case TPACKET_V1_64:
- handle->read_op = pcap_read_linux_mmap_v1_64;
- break;
- #ifdef HAVE_TPACKET2
- case TPACKET_V2:
- handle->read_op = pcap_read_linux_mmap_v2;
- break;
- #endif
- #ifdef HAVE_TPACKET3
- case TPACKET_V3:
- handle->read_op = pcap_read_linux_mmap_v3;
- break;
- #endif
- }
- handle->cleanup_op = pcap_cleanup_linux_mmap;
- handle->setfilter_op = pcap_setfilter_linux_mmap;
- handle->setnonblock_op = pcap_setnonblock_mmap;
- handle->getnonblock_op = pcap_getnonblock_mmap;
- handle->oneshot_callback = pcap_oneshot_mmap;
- handle->selectable_fd = handle->fd;
- return 1;
- }
- #else /* HAVE_PACKET_RING */
- static int
- activate_mmap(pcap_t *handle _U_, int *status _U_)
- {
- return 0;
- }
- #endif /* HAVE_PACKET_RING */
- #ifdef HAVE_PACKET_RING
- #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
- /*
- * Attempt to set the socket to the specified version of the memory-mapped
- * header.
- *
- * Return 0 if we succeed; return 1 if we fail because that version isn't
- * supported; return -1 on any other error, and set handle->errbuf.
- */
- static int
- init_tpacket(pcap_t *handle, int version, const char *version_str)
- {
- struct pcap_linux *handlep = handle->priv;
- int val = version;
- socklen_t len = sizeof(val);
- /*
- * Probe whether kernel supports the specified TPACKET version;
- * this also gets the length of the header for that version.
- */
- if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) {
- if (errno == ENOPROTOOPT || errno == EINVAL)
- return 1; /* no */
- /* Failed to even find out; this is a fatal error. */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't get %s header len on packet socket: %s",
- version_str,
- pcap_strerror(errno));
- return -1;
- }
- handlep->tp_hdrlen = val;
- val = version;
- if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val,
- sizeof(val)) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't activate %s on packet socket: %s",
- version_str,
- pcap_strerror(errno));
- return -1;
- }
- handlep->tp_version = version;
- /* Reserve space for VLAN tag reconstruction */
- val = VLAN_TAG_LEN;
- if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val,
- sizeof(val)) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't set up reserve on packet socket: %s",
- pcap_strerror(errno));
- return -1;
- }
- return 0;
- }
- #endif /* defined HAVE_TPACKET2 || defined HAVE_TPACKET3 */
- /*
- * If the instruction set for which we're compiling has both 32-bit
- * and 64-bit versions, and Linux support for the 64-bit version
- * predates TPACKET_V2, define ISA_64_BIT as the .machine value
- * you get from uname() for the 64-bit version. Otherwise, leave
- * it undefined. (This includes ARM, which has a 64-bit version,
- * but Linux support for it appeared well after TPACKET_V2 support
- * did, so there should never be a case where 32-bit ARM code is
- * running o a 64-bit kernel that only supports TPACKET_V1.)
- *
- * If we've omitted your favorite such architecture, please contribute
- * a patch. (No patch is needed for architectures that are 32-bit-only
- * or for which Linux has no support for 32-bit userland - or for which,
- * as noted, 64-bit support appeared in Linux after TPACKET_V2 support
- * did.)
- */
- #if defined(__i386__)
- #define ISA_64_BIT "x86_64"
- #elif defined(__ppc__)
- #define ISA_64_BIT "ppc64"
- #elif defined(__sparc__)
- #define ISA_64_BIT "sparc64"
- #elif defined(__s390__)
- #define ISA_64_BIT "s390x"
- #elif defined(__mips__)
- #define ISA_64_BIT "mips64"
- #elif defined(__hppa__)
- #define ISA_64_BIT "parisc64"
- #endif
- /*
- * Attempt to set the socket to version 3 of the memory-mapped header and,
- * if that fails because version 3 isn't supported, attempt to fall
- * back to version 2. If version 2 isn't supported, just leave it at
- * version 1.
- *
- * Return 1 if we succeed or if we fail because neither version 2 nor 3 is
- * supported; return -1 on any other error, and set handle->errbuf.
- */
- static int
- prepare_tpacket_socket(pcap_t *handle)
- {
- struct pcap_linux *handlep = handle->priv;
- #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
- int ret;
- #endif
- #ifdef HAVE_TPACKET3
- /*
- * Try setting the version to TPACKET_V3.
- *
- * The only mode in which buffering is done on PF_PACKET
- * sockets, so that packets might not be delivered
- * immediately, is TPACKET_V3 mode.
- *
- * The buffering cannot be disabled in that mode, so
- * if the user has requested immediate mode, we don't
- * use TPACKET_V3.
- */
- if (!handle->opt.immediate) {
- ret = init_tpacket(handle, TPACKET_V3, "TPACKET_V3");
- if (ret == 0) {
- /*
- * Success.
- */
- return 1;
- }
- if (ret == -1) {
- /*
- * We failed for some reason other than "the
- * kernel doesn't support TPACKET_V3".
- */
- return -1;
- }
- }
- #endif /* HAVE_TPACKET3 */
- #ifdef HAVE_TPACKET2
- /*
- * Try setting the version to TPACKET_V2.
- */
- ret = init_tpacket(handle, TPACKET_V2, "TPACKET_V2");
- if (ret == 0) {
- /*
- * Success.
- */
- return 1;
- }
- if (ret == -1) {
- /*
- * We failed for some reason other than "the
- * kernel doesn't support TPACKET_V2".
- */
- return -1;
- }
- #endif /* HAVE_TPACKET2 */
- /*
- * OK, we're using TPACKET_V1, as that's all the kernel supports.
- */
- handlep->tp_version = TPACKET_V1;
- handlep->tp_hdrlen = sizeof(struct tpacket_hdr);
- #ifdef ISA_64_BIT
- /*
- * 32-bit userspace + 64-bit kernel + TPACKET_V1 are not compatible with
- * each other due to platform-dependent data type size differences.
- *
- * If we have a 32-bit userland and a 64-bit kernel, use an
- * internally-defined TPACKET_V1_64, with which we use a 64-bit
- * version of the data structures.
- */
- if (sizeof(long) == 4) {
- /*
- * This is 32-bit code.
- */
- struct utsname utsname;
- if (uname(&utsname) == -1) {
- /*
- * Failed.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "uname failed: %s", pcap_strerror(errno));
- return -1;
- }
- if (strcmp(utsname.machine, ISA_64_BIT) == 0) {
- /*
- * uname() tells us the machine is 64-bit,
- * so we presumably have a 64-bit kernel.
- *
- * XXX - this presumes that uname() won't lie
- * in 32-bit code and claim that the machine
- * has the 32-bit version of the ISA.
- */
- handlep->tp_version = TPACKET_V1_64;
- handlep->tp_hdrlen = sizeof(struct tpacket_hdr_64);
- }
- }
- #endif
- return 1;
- }
- /*
- * Attempt to set up memory-mapped access.
- *
- * On success, returns 1, and sets *status to 0 if there are no warnings
- * or to a PCAP_WARNING_ code if there is a warning.
- *
- * On failure due to lack of support for memory-mapped capture, returns
- * 0.
- *
- * On error, returns -1, and sets *status to the appropriate error code;
- * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
- */
- static int
- create_ring(pcap_t *handle, int *status)
- {
- struct pcap_linux *handlep = handle->priv;
- unsigned i, j, frames_per_block;
- #ifdef HAVE_TPACKET3
- /*
- * For sockets using TPACKET_V1 or TPACKET_V2, the extra
- * stuff at the end of a struct tpacket_req3 will be
- * ignored, so this is OK even for those sockets.
- */
- struct tpacket_req3 req;
- #else
- struct tpacket_req req;
- #endif
- socklen_t len;
- unsigned int sk_type, tp_reserve, maclen, tp_hdrlen, netoff, macoff;
- unsigned int frame_size;
- /*
- * Start out assuming no warnings or errors.
- */
- *status = 0;
- switch (handlep->tp_version) {
- case TPACKET_V1:
- case TPACKET_V1_64:
- #ifdef HAVE_TPACKET2
- case TPACKET_V2:
- #endif
- /* Note that with large snapshot length (say 64K, which is
- * the default for recent versions of tcpdump, the value that
- * "-s 0" has given for a long time with tcpdump, and the
- * default in Wireshark/TShark/dumpcap), if we use the snapshot
- * length to calculate the frame length, only a few frames
- * will be available in the ring even with pretty
- * large ring size (and a lot of memory will be unused).
- *
- * Ideally, we should choose a frame length based on the
- * minimum of the specified snapshot length and the maximum
- * packet size. That's not as easy as it sounds; consider,
- * for example, an 802.11 interface in monitor mode, where
- * the frame would include a radiotap header, where the
- * maximum radiotap header length is device-dependent.
- *
- * So, for now, we just do this for Ethernet devices, where
- * there's no metadata header, and the link-layer header is
- * fixed length. We can get the maximum packet size by
- * adding 18, the Ethernet header length plus the CRC length
- * (just in case we happen to get the CRC in the packet), to
- * the MTU of the interface; we fetch the MTU in the hopes
- * that it reflects support for jumbo frames. (Even if the
- * interface is just being used for passive snooping, the
- * driver might set the size of buffers in the receive ring
- * based on the MTU, so that the MTU limits the maximum size
- * of packets that we can receive.)
- *
- * We don't do that if segmentation/fragmentation or receive
- * offload are enabled, so we don't get rudely surprised by
- * "packets" bigger than the MTU. */
- frame_size = handle->snapshot;
- if (handle->linktype == DLT_EN10MB) {
- int mtu;
- int offload;
- offload = iface_get_offload(handle);
- if (offload == -1) {
- *status = PCAP_ERROR;
- return -1;
- }
- if (!offload) {
- mtu = iface_get_mtu(handle->fd, handle->opt.source,
- handle->errbuf);
- if (mtu == -1) {
- *status = PCAP_ERROR;
- return -1;
- }
- if (frame_size > mtu + 18)
- frame_size = mtu + 18;
- }
- }
- /* NOTE: calculus matching those in tpacket_rcv()
- * in linux-2.6/net/packet/af_packet.c
- */
- len = sizeof(sk_type);
- if (getsockopt(handle->fd, SOL_SOCKET, SO_TYPE, &sk_type,
- &len) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "getsockopt: %s", pcap_strerror(errno));
- *status = PCAP_ERROR;
- return -1;
- }
- #ifdef PACKET_RESERVE
- len = sizeof(tp_reserve);
- if (getsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE,
- &tp_reserve, &len) < 0) {
- if (errno != ENOPROTOOPT) {
- /*
- * ENOPROTOOPT means "kernel doesn't support
- * PACKET_RESERVE", in which case we fall back
- * as best we can.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "getsockopt: %s", pcap_strerror(errno));
- *status = PCAP_ERROR;
- return -1;
- }
- tp_reserve = 0; /* older kernel, reserve not supported */
- }
- #else
- tp_reserve = 0; /* older kernel, reserve not supported */
- #endif
- maclen = (sk_type == SOCK_DGRAM) ? 0 : MAX_LINKHEADER_SIZE;
- /* XXX: in the kernel maclen is calculated from
- * LL_ALLOCATED_SPACE(dev) and vnet_hdr.hdr_len
- * in: packet_snd() in linux-2.6/net/packet/af_packet.c
- * then packet_alloc_skb() in linux-2.6/net/packet/af_packet.c
- * then sock_alloc_send_pskb() in linux-2.6/net/core/sock.c
- * but I see no way to get those sizes in userspace,
- * like for instance with an ifreq ioctl();
- * the best thing I've found so far is MAX_HEADER in
- * the kernel part of linux-2.6/include/linux/netdevice.h
- * which goes up to 128+48=176; since pcap-linux.c
- * defines a MAX_LINKHEADER_SIZE of 256 which is
- * greater than that, let's use it.. maybe is it even
- * large enough to directly replace macoff..
- */
- tp_hdrlen = TPACKET_ALIGN(handlep->tp_hdrlen) + sizeof(struct sockaddr_ll) ;
- netoff = TPACKET_ALIGN(tp_hdrlen + (maclen < 16 ? 16 : maclen)) + tp_reserve;
- /* NOTE: AFAICS tp_reserve may break the TPACKET_ALIGN
- * of netoff, which contradicts
- * linux-2.6/Documentation/networking/packet_mmap.txt
- * documenting that:
- * "- Gap, chosen so that packet data (Start+tp_net)
- * aligns to TPACKET_ALIGNMENT=16"
- */
- /* NOTE: in linux-2.6/include/linux/skbuff.h:
- * "CPUs often take a performance hit
- * when accessing unaligned memory locations"
- */
- macoff = netoff - maclen;
- req.tp_frame_size = TPACKET_ALIGN(macoff + frame_size);
- req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size;
- break;
- #ifdef HAVE_TPACKET3
- case TPACKET_V3:
- /* The "frames" for this are actually buffers that
- * contain multiple variable-sized frames.
- *
- * We pick a "frame" size of 128K to leave enough
- * room for at least one reasonably-sized packet
- * in the "frame". */
- req.tp_frame_size = MAXIMUM_SNAPLEN;
- req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size;
- break;
- #endif
- default:
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "Internal error: unknown TPACKET_ value %u",
- handlep->tp_version);
- *status = PCAP_ERROR;
- return -1;
- }
- /* compute the minumum block size that will handle this frame.
- * The block has to be page size aligned.
- * The max block size allowed by the kernel is arch-dependent and
- * it's not explicitly checked here. */
- req.tp_block_size = getpagesize();
- while (req.tp_block_size < req.tp_frame_size)
- req.tp_block_size <<= 1;
- frames_per_block = req.tp_block_size/req.tp_frame_size;
- /*
- * PACKET_TIMESTAMP was added after linux/net_tstamp.h was,
- * so we check for PACKET_TIMESTAMP. We check for
- * linux/net_tstamp.h just in case a system somehow has
- * PACKET_TIMESTAMP but not linux/net_tstamp.h; that might
- * be unnecessary.
- *
- * SIOCSHWTSTAMP was introduced in the patch that introduced
- * linux/net_tstamp.h, so we don't bother checking whether
- * SIOCSHWTSTAMP is defined (if your Linux system has
- * linux/net_tstamp.h but doesn't define SIOCSHWTSTAMP, your
- * Linux system is badly broken).
- */
- #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
- /*
- * If we were told to do so, ask the kernel and the driver
- * to use hardware timestamps.
- *
- * Hardware timestamps are only supported with mmapped
- * captures.
- */
- if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER ||
- handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER_UNSYNCED) {
- struct hwtstamp_config hwconfig;
- struct ifreq ifr;
- int timesource;
- /*
- * Ask for hardware time stamps on all packets,
- * including transmitted packets.
- */
- memset(&hwconfig, 0, sizeof(hwconfig));
- hwconfig.tx_type = HWTSTAMP_TX_ON;
- hwconfig.rx_filter = HWTSTAMP_FILTER_ALL;
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
- ifr.ifr_data = (void *)&hwconfig;
- if (ioctl(handle->fd, SIOCSHWTSTAMP, &ifr) < 0) {
- switch (errno) {
- case EPERM:
- /*
- * Treat this as an error, as the
- * user should try to run this
- * with the appropriate privileges -
- * and, if they can't, shouldn't
- * try requesting hardware time stamps.
- */
- *status = PCAP_ERROR_PERM_DENIED;
- return -1;
- case EOPNOTSUPP:
- /*
- * Treat this as a warning, as the
- * only way to fix the warning is to
- * get an adapter that supports hardware
- * time stamps. We'll just fall back
- * on the standard host time stamps.
- */
- *status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP;
- break;
- default:
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SIOCSHWTSTAMP failed: %s",
- pcap_strerror(errno));
- *status = PCAP_ERROR;
- return -1;
- }
- } else {
- /*
- * Well, that worked. Now specify the type of
- * hardware time stamp we want for this
- * socket.
- */
- if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER) {
- /*
- * Hardware timestamp, synchronized
- * with the system clock.
- */
- timesource = SOF_TIMESTAMPING_SYS_HARDWARE;
- } else {
- /*
- * PCAP_TSTAMP_ADAPTER_UNSYNCED - hardware
- * timestamp, not synchronized with the
- * system clock.
- */
- timesource = SOF_TIMESTAMPING_RAW_HARDWARE;
- }
- if (setsockopt(handle->fd, SOL_PACKET, PACKET_TIMESTAMP,
- (void *)×ource, sizeof(timesource))) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't set PACKET_TIMESTAMP: %s",
- pcap_strerror(errno));
- *status = PCAP_ERROR;
- return -1;
- }
- }
- }
- #endif /* HAVE_LINUX_NET_TSTAMP_H && PACKET_TIMESTAMP */
- /* ask the kernel to create the ring */
- retry:
- req.tp_block_nr = req.tp_frame_nr / frames_per_block;
- /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */
- req.tp_frame_nr = req.tp_block_nr * frames_per_block;
- #ifdef HAVE_TPACKET3
- /* timeout value to retire block - use the configured buffering timeout, or default if <0. */
- req.tp_retire_blk_tov = (handlep->timeout>=0)?handlep->timeout:0;
- /* private data not used */
- req.tp_sizeof_priv = 0;
- /* Rx ring - feature request bits - none (rxhash will not be filled) */
- req.tp_feature_req_word = 0;
- #endif
- if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
- (void *) &req, sizeof(req))) {
- if ((errno == ENOMEM) && (req.tp_block_nr > 1)) {
- /*
- * Memory failure; try to reduce the requested ring
- * size.
- *
- * We used to reduce this by half -- do 5% instead.
- * That may result in more iterations and a longer
- * startup, but the user will be much happier with
- * the resulting buffer size.
- */
- if (req.tp_frame_nr < 20)
- req.tp_frame_nr -= 1;
- else
- req.tp_frame_nr -= req.tp_frame_nr/20;
- goto retry;
- }
- if (errno == ENOPROTOOPT) {
- /*
- * We don't have ring buffer support in this kernel.
- */
- return 0;
- }
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't create rx ring on packet socket: %s",
- pcap_strerror(errno));
- *status = PCAP_ERROR;
- return -1;
- }
- /* memory map the rx ring */
- handlep->mmapbuflen = req.tp_block_nr * req.tp_block_size;
- handlep->mmapbuf = mmap(0, handlep->mmapbuflen,
- PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0);
- if (handlep->mmapbuf == MAP_FAILED) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't mmap rx ring: %s", pcap_strerror(errno));
- /* clear the allocated ring on error*/
- destroy_ring(handle);
- *status = PCAP_ERROR;
- return -1;
- }
- /* allocate a ring for each frame header pointer*/
- handle->cc = req.tp_frame_nr;
- handle->buffer = malloc(handle->cc * sizeof(union thdr *));
- if (!handle->buffer) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't allocate ring of frame headers: %s",
- pcap_strerror(errno));
- destroy_ring(handle);
- *status = PCAP_ERROR;
- return -1;
- }
- /* fill the header ring with proper frame ptr*/
- handle->offset = 0;
- for (i=0; i<req.tp_block_nr; ++i) {
- void *base = &handlep->mmapbuf[i*req.tp_block_size];
- for (j=0; j<frames_per_block; ++j, ++handle->offset) {
- RING_GET_FRAME(handle) = base;
- base += req.tp_frame_size;
- }
- }
- handle->bufsize = req.tp_frame_size;
- handle->offset = 0;
- return 1;
- }
- /* free all ring related resources*/
- static void
- destroy_ring(pcap_t *handle)
- {
- struct pcap_linux *handlep = handle->priv;
- /* tell the kernel to destroy the ring*/
- struct tpacket_req req;
- memset(&req, 0, sizeof(req));
- /* do not test for setsockopt failure, as we can't recover from any error */
- (void)setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
- (void *) &req, sizeof(req));
- /* if ring is mapped, unmap it*/
- if (handlep->mmapbuf) {
- /* do not test for mmap failure, as we can't recover from any error */
- (void)munmap(handlep->mmapbuf, handlep->mmapbuflen);
- handlep->mmapbuf = NULL;
- }
- }
- /*
- * Special one-shot callback, used for pcap_next() and pcap_next_ex(),
- * for Linux mmapped capture.
- *
- * The problem is that pcap_next() and pcap_next_ex() expect the packet
- * data handed to the callback to be valid after the callback returns,
- * but pcap_read_linux_mmap() has to release that packet as soon as
- * the callback returns (otherwise, the kernel thinks there's still
- * at least one unprocessed packet available in the ring, so a select()
- * will immediately return indicating that there's data to process), so,
- * in the callback, we have to make a copy of the packet.
- *
- * Yes, this means that, if the capture is using the ring buffer, using
- * pcap_next() or pcap_next_ex() requires more copies than using
- * pcap_loop() or pcap_dispatch(). If that bothers you, don't use
- * pcap_next() or pcap_next_ex().
- */
- static void
- pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
- const u_char *bytes)
- {
- struct oneshot_userdata *sp = (struct oneshot_userdata *)user;
- pcap_t *handle = sp->pd;
- struct pcap_linux *handlep = handle->priv;
- *sp->hdr = *h;
- memcpy(handlep->oneshot_buffer, bytes, h->caplen);
- *sp->pkt = handlep->oneshot_buffer;
- }
- static void
- pcap_cleanup_linux_mmap( pcap_t *handle )
- {
- struct pcap_linux *handlep = handle->priv;
- destroy_ring(handle);
- if (handlep->oneshot_buffer != NULL) {
- free(handlep->oneshot_buffer);
- handlep->oneshot_buffer = NULL;
- }
- pcap_cleanup_linux(handle);
- }
- static int
- pcap_getnonblock_mmap(pcap_t *p, char *errbuf)
- {
- struct pcap_linux *handlep = p->priv;
- /* use negative value of timeout to indicate non blocking ops */
- return (handlep->timeout<0);
- }
- static int
- pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf)
- {
- struct pcap_linux *handlep = p->priv;
- /*
- * Set the file descriptor to non-blocking mode, as we use
- * it for sending packets.
- */
- if (pcap_setnonblock_fd(p, nonblock, errbuf) == -1)
- return -1;
- /*
- * Map each value to their corresponding negation to
- * preserve the timeout value provided with pcap_set_timeout.
- */
- if (nonblock) {
- if (handlep->timeout >= 0) {
- /*
- * Indicate that we're switching to
- * non-blocking mode.
- */
- handlep->timeout = ~handlep->timeout;
- }
- } else {
- if (handlep->timeout < 0) {
- handlep->timeout = ~handlep->timeout;
- }
- }
- return 0;
- }
- static inline union thdr *
- pcap_get_ring_frame(pcap_t *handle, int status)
- {
- struct pcap_linux *handlep = handle->priv;
- union thdr h;
- h.raw = RING_GET_FRAME(handle);
- switch (handlep->tp_version) {
- case TPACKET_V1:
- if (status != (h.h1->tp_status ? TP_STATUS_USER :
- TP_STATUS_KERNEL))
- return NULL;
- break;
- case TPACKET_V1_64:
- if (status != (h.h1_64->tp_status ? TP_STATUS_USER :
- TP_STATUS_KERNEL))
- return NULL;
- break;
- #ifdef HAVE_TPACKET2
- case TPACKET_V2:
- if (status != (h.h2->tp_status ? TP_STATUS_USER :
- TP_STATUS_KERNEL))
- return NULL;
- break;
- #endif
- #ifdef HAVE_TPACKET3
- case TPACKET_V3:
- if (status != (h.h3->hdr.bh1.block_status ? TP_STATUS_USER :
- TP_STATUS_KERNEL))
- return NULL;
- break;
- #endif
- }
- return h.raw;
- }
- #ifndef POLLRDHUP
- #define POLLRDHUP 0
- #endif
- /* wait for frames availability.*/
- static int pcap_wait_for_frames_mmap(pcap_t *handle)
- {
- if (!pcap_get_ring_frame(handle, TP_STATUS_USER)) {
- struct pcap_linux *handlep = handle->priv;
- int timeout;
- char c;
- struct pollfd pollinfo;
- int ret;
- pollinfo.fd = handle->fd;
- pollinfo.events = POLLIN;
- if (handlep->timeout == 0) {
- #ifdef HAVE_TPACKET3
- /*
- * XXX - due to a set of (mis)features in the
- * TPACKET_V3 kernel code, blocking forever with
- * a TPACKET_V3 socket can, if few packets
- * are arriving and passing the socket filter,
- * cause most packets to be dropped. See
- * libpcap issue #335 for the full painful
- * story. The workaround is to have poll()
- * time out very quickly, so we grab the
- * frames handed to us, and return them to
- * the kernel, ASAP.
- *
- * If those issues are ever fixed, we might
- * want to check the kernel version and block
- * forever with TPACKET_V3 if we're running
- * with a kernel that has the fix.
- */
- if (handlep->tp_version == TPACKET_V3)
- timeout = 1; /* don't block for very long */
- else
- #endif
- timeout = -1; /* block forever */
- } else if (handlep->timeout > 0)
- timeout = handlep->timeout; /* block for that amount of time */
- else
- timeout = 0; /* non-blocking mode - poll to pick up errors */
- do {
- ret = poll(&pollinfo, 1, timeout);
- if (ret < 0 && errno != EINTR) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't poll on packet socket: %s",
- pcap_strerror(errno));
- return PCAP_ERROR;
- } else if (ret > 0 &&
- (pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) {
- /*
- * There's some indication other than
- * "you can read on this descriptor" on
- * the descriptor.
- */
- if (pollinfo.revents & (POLLHUP | POLLRDHUP)) {
- snprintf(handle->errbuf,
- PCAP_ERRBUF_SIZE,
- "Hangup on packet socket");
- return PCAP_ERROR;
- }
- if (pollinfo.revents & POLLERR) {
- /*
- * A recv() will give us the
- * actual error code.
- *
- * XXX - make the socket non-blocking?
- */
- if (recv(handle->fd, &c, sizeof c,
- MSG_PEEK) != -1)
- continue; /* what, no error? */
- if (errno == ENETDOWN) {
- /*
- * The device on which we're
- * capturing went away.
- *
- * XXX - we should really return
- * PCAP_ERROR_IFACE_NOT_UP,
- * but pcap_dispatch() etc.
- * aren't defined to return
- * that.
- */
- snprintf(handle->errbuf,
- PCAP_ERRBUF_SIZE,
- "The interface went down");
- } else {
- snprintf(handle->errbuf,
- PCAP_ERRBUF_SIZE,
- "Error condition on packet socket: %s",
- strerror(errno));
- }
- return PCAP_ERROR;
- }
- if (pollinfo.revents & POLLNVAL) {
- snprintf(handle->errbuf,
- PCAP_ERRBUF_SIZE,
- "Invalid polling request on packet socket");
- return PCAP_ERROR;
- }
- }
- /* check for break loop condition on interrupted syscall*/
- if (handle->break_loop) {
- handle->break_loop = 0;
- return PCAP_ERROR_BREAK;
- }
- } while (ret < 0);
- }
- return 0;
- }
- /* handle a single memory mapped packet */
- static int pcap_handle_packet_mmap(
- pcap_t *handle,
- pcap_handler callback,
- u_char *user,
- unsigned char *frame,
- unsigned int tp_len,
- unsigned int tp_mac,
- unsigned int tp_snaplen,
- unsigned int tp_sec,
- unsigned int tp_usec,
- int tp_vlan_tci_valid,
- __u16 tp_vlan_tci,
- __u16 tp_vlan_tpid)
- {
- struct pcap_linux *handlep = handle->priv;
- unsigned char *bp;
- struct sockaddr_ll *sll;
- struct pcap_pkthdr pcaphdr;
- /* perform sanity check on internal offset. */
- if (tp_mac + tp_snaplen > handle->bufsize) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "corrupted frame on kernel ring mac "
- "offset %u + caplen %u > frame len %d",
- tp_mac, tp_snaplen, handle->bufsize);
- return -1;
- }
- /* run filter on received packet
- * If the kernel filtering is enabled we need to run the
- * filter until all the frames present into the ring
- * at filter creation time are processed.
- * In this case, blocks_to_filter_in_userland is used
- * as a counter for the packet we need to filter.
- * Note: alternatively it could be possible to stop applying
- * the filter when the ring became empty, but it can possibly
- * happen a lot later... */
- bp = frame + tp_mac;
- /* if required build in place the sll header*/
- sll = (void *)frame + TPACKET_ALIGN(handlep->tp_hdrlen);
- if (handlep->cooked) {
- struct sll_header *hdrp;
- /*
- * The kernel should have left us with enough
- * space for an sll header; back up the packet
- * data pointer into that space, as that'll be
- * the beginning of the packet we pass to the
- * callback.
- */
- bp -= SLL_HDR_LEN;
- /*
- * Let's make sure that's past the end of
- * the tpacket header, i.e. >=
- * ((u_char *)thdr + TPACKET_HDRLEN), so we
- * don't step on the header when we construct
- * the sll header.
- */
- if (bp < (u_char *)frame +
- TPACKET_ALIGN(handlep->tp_hdrlen) +
- sizeof(struct sockaddr_ll)) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "cooked-mode frame doesn't have room for sll header");
- return -1;
- }
- /*
- * OK, that worked; construct the sll header.
- */
- hdrp = (struct sll_header *)bp;
- hdrp->sll_pkttype = map_packet_type_to_sll_type(
- sll->sll_pkttype);
- hdrp->sll_hatype = htons(sll->sll_hatype);
- hdrp->sll_halen = htons(sll->sll_halen);
- memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN);
- hdrp->sll_protocol = sll->sll_protocol;
- }
- if (handlep->filter_in_userland && handle->fcode.bf_insns) {
- struct bpf_aux_data aux_data;
- aux_data.vlan_tag = tp_vlan_tci & 0x0fff;
- aux_data.vlan_tag_present = tp_vlan_tci_valid;
- if (bpf_filter_with_aux_data(handle->fcode.bf_insns, bp,
- tp_len, tp_snaplen, &aux_data) == 0)
- return 0;
- }
- if (!linux_check_direction(handle, sll))
- return 0;
- /* get required packet info from ring header */
- pcaphdr.ts.tv_sec = tp_sec;
- pcaphdr.ts.tv_usec = tp_usec;
- pcaphdr.caplen = tp_snaplen;
- pcaphdr.len = tp_len;
- /* if required build in place the sll header*/
- if (handlep->cooked) {
- /* update packet len */
- pcaphdr.caplen += SLL_HDR_LEN;
- pcaphdr.len += SLL_HDR_LEN;
- }
- #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
- if (tp_vlan_tci_valid &&
- handlep->vlan_offset != -1 &&
- tp_snaplen >= (unsigned int) handlep->vlan_offset)
- {
- struct vlan_tag *tag;
- bp -= VLAN_TAG_LEN;
- memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
- tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
- tag->vlan_tpid = htons(tp_vlan_tpid);
- tag->vlan_tci = htons(tp_vlan_tci);
- pcaphdr.caplen += VLAN_TAG_LEN;
- pcaphdr.len += VLAN_TAG_LEN;
- }
- #endif
- /*
- * The only way to tell the kernel to cut off the
- * packet at a snapshot length is with a filter program;
- * if there's no filter program, the kernel won't cut
- * the packet off.
- *
- * Trim the snapshot length to be no longer than the
- * specified snapshot length.
- */
- if (pcaphdr.caplen > handle->snapshot)
- pcaphdr.caplen = handle->snapshot;
- /* pass the packet to the user */
- callback(user, &pcaphdr, bp);
- return 1;
- }
- static int
- pcap_read_linux_mmap_v1(pcap_t *handle, int max_packets, pcap_handler callback,
- u_char *user)
- {
- struct pcap_linux *handlep = handle->priv;
- int pkts = 0;
- int ret;
- /* wait for frames availability.*/
- ret = pcap_wait_for_frames_mmap(handle);
- if (ret) {
- return ret;
- }
- /* non-positive values of max_packets are used to require all
- * packets currently available in the ring */
- while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
- union thdr h;
- h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
- if (!h.raw)
- break;
- ret = pcap_handle_packet_mmap(
- handle,
- callback,
- user,
- h.raw,
- h.h1->tp_len,
- h.h1->tp_mac,
- h.h1->tp_snaplen,
- h.h1->tp_sec,
- h.h1->tp_usec,
- 0,
- 0,
- 0);
- if (ret == 1) {
- pkts++;
- handlep->packets_read++;
- } else if (ret < 0) {
- return ret;
- }
- /*
- * Hand this block back to the kernel, and, if we're
- * counting blocks that need to be filtered in userland
- * after having been filtered by the kernel, count
- * the one we've just processed.
- */
- h.h1->tp_status = TP_STATUS_KERNEL;
- if (handlep->blocks_to_filter_in_userland > 0) {
- handlep->blocks_to_filter_in_userland--;
- if (handlep->blocks_to_filter_in_userland == 0) {
- /*
- * No more blocks need to be filtered
- * in userland.
- */
- handlep->filter_in_userland = 0;
- }
- }
- /* next block */
- if (++handle->offset >= handle->cc)
- handle->offset = 0;
- /* check for break loop condition*/
- if (handle->break_loop) {
- handle->break_loop = 0;
- return PCAP_ERROR_BREAK;
- }
- }
- return pkts;
- }
- static int
- pcap_read_linux_mmap_v1_64(pcap_t *handle, int max_packets, pcap_handler callback,
- u_char *user)
- {
- struct pcap_linux *handlep = handle->priv;
- int pkts = 0;
- int ret;
- /* wait for frames availability.*/
- ret = pcap_wait_for_frames_mmap(handle);
- if (ret) {
- return ret;
- }
- /* non-positive values of max_packets are used to require all
- * packets currently available in the ring */
- while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
- union thdr h;
- h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
- if (!h.raw)
- break;
- ret = pcap_handle_packet_mmap(
- handle,
- callback,
- user,
- h.raw,
- h.h1_64->tp_len,
- h.h1_64->tp_mac,
- h.h1_64->tp_snaplen,
- h.h1_64->tp_sec,
- h.h1_64->tp_usec,
- 0,
- 0,
- 0);
- if (ret == 1) {
- pkts++;
- handlep->packets_read++;
- } else if (ret < 0) {
- return ret;
- }
- /*
- * Hand this block back to the kernel, and, if we're
- * counting blocks that need to be filtered in userland
- * after having been filtered by the kernel, count
- * the one we've just processed.
- */
- h.h1_64->tp_status = TP_STATUS_KERNEL;
- if (handlep->blocks_to_filter_in_userland > 0) {
- handlep->blocks_to_filter_in_userland--;
- if (handlep->blocks_to_filter_in_userland == 0) {
- /*
- * No more blocks need to be filtered
- * in userland.
- */
- handlep->filter_in_userland = 0;
- }
- }
- /* next block */
- if (++handle->offset >= handle->cc)
- handle->offset = 0;
- /* check for break loop condition*/
- if (handle->break_loop) {
- handle->break_loop = 0;
- return PCAP_ERROR_BREAK;
- }
- }
- return pkts;
- }
- #ifdef HAVE_TPACKET2
- static int
- pcap_read_linux_mmap_v2(pcap_t *handle, int max_packets, pcap_handler callback,
- u_char *user)
- {
- struct pcap_linux *handlep = handle->priv;
- int pkts = 0;
- int ret;
- /* wait for frames availability.*/
- ret = pcap_wait_for_frames_mmap(handle);
- if (ret) {
- return ret;
- }
- /* non-positive values of max_packets are used to require all
- * packets currently available in the ring */
- while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
- union thdr h;
- h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
- if (!h.raw)
- break;
- ret = pcap_handle_packet_mmap(
- handle,
- callback,
- user,
- h.raw,
- h.h2->tp_len,
- h.h2->tp_mac,
- h.h2->tp_snaplen,
- h.h2->tp_sec,
- handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? h.h2->tp_nsec : h.h2->tp_nsec / 1000,
- #if defined(TP_STATUS_VLAN_VALID)
- (h.h2->tp_vlan_tci || (h.h2->tp_status & TP_STATUS_VLAN_VALID)),
- #else
- h.h2->tp_vlan_tci != 0,
- #endif
- h.h2->tp_vlan_tci,
- VLAN_TPID(h.h2, h.h2));
- if (ret == 1) {
- pkts++;
- handlep->packets_read++;
- } else if (ret < 0) {
- return ret;
- }
- /*
- * Hand this block back to the kernel, and, if we're
- * counting blocks that need to be filtered in userland
- * after having been filtered by the kernel, count
- * the one we've just processed.
- */
- h.h2->tp_status = TP_STATUS_KERNEL;
- if (handlep->blocks_to_filter_in_userland > 0) {
- handlep->blocks_to_filter_in_userland--;
- if (handlep->blocks_to_filter_in_userland == 0) {
- /*
- * No more blocks need to be filtered
- * in userland.
- */
- handlep->filter_in_userland = 0;
- }
- }
- /* next block */
- if (++handle->offset >= handle->cc)
- handle->offset = 0;
- /* check for break loop condition*/
- if (handle->break_loop) {
- handle->break_loop = 0;
- return PCAP_ERROR_BREAK;
- }
- }
- return pkts;
- }
- #endif /* HAVE_TPACKET2 */
- #ifdef HAVE_TPACKET3
- static int
- pcap_read_linux_mmap_v3(pcap_t *handle, int max_packets, pcap_handler callback,
- u_char *user)
- {
- struct pcap_linux *handlep = handle->priv;
- union thdr h;
- int pkts = 0;
- int ret;
- again:
- if (handlep->current_packet == NULL) {
- /* wait for frames availability.*/
- ret = pcap_wait_for_frames_mmap(handle);
- if (ret) {
- return ret;
- }
- }
- h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
- if (!h.raw) {
- if (pkts == 0 && handlep->timeout == 0) {
- /* Block until we see a packet. */
- goto again;
- }
- return pkts;
- }
- /* non-positive values of max_packets are used to require all
- * packets currently available in the ring */
- while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
- if (handlep->current_packet == NULL) {
- h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
- if (!h.raw)
- break;
- handlep->current_packet = h.raw + h.h3->hdr.bh1.offset_to_first_pkt;
- handlep->packets_left = h.h3->hdr.bh1.num_pkts;
- }
- int packets_to_read = handlep->packets_left;
- if (!PACKET_COUNT_IS_UNLIMITED(max_packets) && packets_to_read > max_packets) {
- packets_to_read = max_packets;
- }
- while(packets_to_read--) {
- struct tpacket3_hdr* tp3_hdr = (struct tpacket3_hdr*) handlep->current_packet;
- ret = pcap_handle_packet_mmap(
- handle,
- callback,
- user,
- handlep->current_packet,
- tp3_hdr->tp_len,
- tp3_hdr->tp_mac,
- tp3_hdr->tp_snaplen,
- tp3_hdr->tp_sec,
- handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? tp3_hdr->tp_nsec : tp3_hdr->tp_nsec / 1000,
- #if defined(TP_STATUS_VLAN_VALID)
- (tp3_hdr->hv1.tp_vlan_tci || (tp3_hdr->tp_status & TP_STATUS_VLAN_VALID)),
- #else
- tp3_hdr->hv1.tp_vlan_tci != 0,
- #endif
- tp3_hdr->hv1.tp_vlan_tci,
- VLAN_TPID(tp3_hdr, &tp3_hdr->hv1));
- if (ret == 1) {
- pkts++;
- handlep->packets_read++;
- } else if (ret < 0) {
- handlep->current_packet = NULL;
- return ret;
- }
- handlep->current_packet += tp3_hdr->tp_next_offset;
- handlep->packets_left--;
- }
- if (handlep->packets_left <= 0) {
- /*
- * Hand this block back to the kernel, and, if
- * we're counting blocks that need to be
- * filtered in userland after having been
- * filtered by the kernel, count the one we've
- * just processed.
- */
- h.h3->hdr.bh1.block_status = TP_STATUS_KERNEL;
- if (handlep->blocks_to_filter_in_userland > 0) {
- handlep->blocks_to_filter_in_userland--;
- if (handlep->blocks_to_filter_in_userland == 0) {
- /*
- * No more blocks need to be filtered
- * in userland.
- */
- handlep->filter_in_userland = 0;
- }
- }
- /* next block */
- if (++handle->offset >= handle->cc)
- handle->offset = 0;
- handlep->current_packet = NULL;
- }
- /* check for break loop condition*/
- if (handle->break_loop) {
- handle->break_loop = 0;
- return PCAP_ERROR_BREAK;
- }
- }
- if (pkts == 0 && handlep->timeout == 0) {
- /* Block until we see a packet. */
- goto again;
- }
- return pkts;
- }
- #endif /* HAVE_TPACKET3 */
- static int
- pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter)
- {
- struct pcap_linux *handlep = handle->priv;
- int n, offset;
- int ret;
- /*
- * Don't rewrite "ret" instructions; we don't need to, as
- * we're not reading packets with recvmsg(), and we don't
- * want to, as, by not rewriting them, the kernel can avoid
- * copying extra data.
- */
- ret = pcap_setfilter_linux_common(handle, filter, 1);
- if (ret < 0)
- return ret;
- /*
- * If we're filtering in userland, there's nothing to do;
- * the new filter will be used for the next packet.
- */
- if (handlep->filter_in_userland)
- return ret;
- /*
- * We're filtering in the kernel; the packets present in
- * all blocks currently in the ring were already filtered
- * by the old filter, and so will need to be filtered in
- * userland by the new filter.
- *
- * Get an upper bound for the number of such blocks; first,
- * walk the ring backward and count the free blocks.
- */
- offset = handle->offset;
- if (--handle->offset < 0)
- handle->offset = handle->cc - 1;
- for (n=0; n < handle->cc; ++n) {
- if (--handle->offset < 0)
- handle->offset = handle->cc - 1;
- if (!pcap_get_ring_frame(handle, TP_STATUS_KERNEL))
- break;
- }
- /*
- * If we found free blocks, decrement the count of free
- * blocks by 1, just in case we lost a race with another
- * thread of control that was adding a packet while
- * we were counting and that had run the filter before
- * we changed it.
- *
- * XXX - could there be more than one block added in
- * this fashion?
- *
- * XXX - is there a way to avoid that race, e.g. somehow
- * wait for all packets that passed the old filter to
- * be added to the ring?
- */
- if (n != 0)
- n--;
- /* be careful to not change current ring position */
- handle->offset = offset;
- /*
- * Set the count of blocks worth of packets to filter
- * in userland to the total number of blocks in the
- * ring minus the number of free blocks we found, and
- * turn on userland filtering. (The count of blocks
- * worth of packets to filter in userland is guaranteed
- * not to be zero - n, above, couldn't be set to a
- * value > handle->cc, and if it were equal to
- * handle->cc, it wouldn't be zero, and thus would
- * be decremented to handle->cc - 1.)
- */
- handlep->blocks_to_filter_in_userland = handle->cc - n;
- handlep->filter_in_userland = 1;
- return ret;
- }
- #endif /* HAVE_PACKET_RING */
- #ifdef HAVE_PF_PACKET_SOCKETS
- /*
- * Return the index of the given device name. Fill ebuf and return
- * -1 on failure.
- */
- static int
- iface_get_id(int fd, const char *device, char *ebuf)
- {
- struct ifreq ifr;
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "SIOCGIFINDEX: %s", pcap_strerror(errno));
- return -1;
- }
- return ifr.ifr_ifindex;
- }
- /*
- * Bind the socket associated with FD to the given device.
- * Return 1 on success, 0 if we should try a SOCK_PACKET socket,
- * or a PCAP_ERROR_ value on a hard error.
- */
- static int
- iface_bind(int fd, int ifindex, char *ebuf)
- {
- struct sockaddr_ll sll;
- int err;
- socklen_t errlen = sizeof(err);
- memset(&sll, 0, sizeof(sll));
- sll.sll_family = AF_PACKET;
- sll.sll_ifindex = ifindex;
- sll.sll_protocol = htons(ETH_P_ALL);
- if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
- if (errno == ENETDOWN) {
- /*
- * Return a "network down" indication, so that
- * the application can report that rather than
- * saying we had a mysterious failure and
- * suggest that they report a problem to the
- * libpcap developers.
- */
- return PCAP_ERROR_IFACE_NOT_UP;
- } else {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- }
- /* Any pending errors, e.g., network is down? */
- if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "getsockopt: %s", pcap_strerror(errno));
- return 0;
- }
- if (err == ENETDOWN) {
- /*
- * Return a "network down" indication, so that
- * the application can report that rather than
- * saying we had a mysterious failure and
- * suggest that they report a problem to the
- * libpcap developers.
- */
- return PCAP_ERROR_IFACE_NOT_UP;
- } else if (err > 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(err));
- return 0;
- }
- return 1;
- }
- #ifdef IW_MODE_MONITOR
- /*
- * Check whether the device supports the Wireless Extensions.
- * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE
- * if the device doesn't even exist.
- */
- static int
- has_wext(int sock_fd, const char *device, char *ebuf)
- {
- struct iwreq ireq;
- if (is_bonding_device(sock_fd, device))
- return 0; /* bonding device, so don't even try */
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0)
- return 1; /* yes */
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCGIWNAME: %s", device, pcap_strerror(errno));
- if (errno == ENODEV)
- return PCAP_ERROR_NO_SUCH_DEVICE;
- return 0;
- }
- /*
- * Per me si va ne la citta dolente,
- * Per me si va ne l'etterno dolore,
- * ...
- * Lasciate ogne speranza, voi ch'intrate.
- *
- * XXX - airmon-ng does special stuff with the Orinoco driver and the
- * wlan-ng driver.
- */
- typedef enum {
- MONITOR_WEXT,
- MONITOR_HOSTAP,
- MONITOR_PRISM,
- MONITOR_PRISM54,
- MONITOR_ACX100,
- MONITOR_RT2500,
- MONITOR_RT2570,
- MONITOR_RT73,
- MONITOR_RTL8XXX
- } monitor_type;
- /*
- * Use the Wireless Extensions, if we have them, to try to turn monitor mode
- * on if it's not already on.
- *
- * Returns 1 on success, 0 if we don't support the Wireless Extensions
- * on this device, or a PCAP_ERROR_ value if we do support them but
- * we weren't able to turn monitor mode on.
- */
- static int
- enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device)
- {
- /*
- * XXX - at least some adapters require non-Wireless Extensions
- * mechanisms to turn monitor mode on.
- *
- * Atheros cards might require that a separate "monitor virtual access
- * point" be created, with later versions of the madwifi driver.
- * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode
- * monitor -bssid", which apparently spits out a line "athN"
- * where "athN" is the monitor mode device. To leave monitor
- * mode, it destroys the monitor mode device.
- *
- * Some Intel Centrino adapters might require private ioctls to get
- * radio headers; the ipw2200 and ipw3945 drivers allow you to
- * configure a separate "rtapN" interface to capture in monitor
- * mode without preventing the adapter from operating normally.
- * (airmon-ng doesn't appear to use that, though.)
- *
- * It would be Truly Wonderful if mac80211 and nl80211 cleaned this
- * up, and if all drivers were converted to mac80211 drivers.
- *
- * If interface {if} is a mac80211 driver, the file
- * /sys/class/net/{if}/phy80211 is a symlink to
- * /sys/class/ieee80211/{phydev}, for some {phydev}.
- *
- * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
- * least, has a "wmaster0" device and a "wlan0" device; the
- * latter is the one with the IP address. Both show up in
- * "tcpdump -D" output. Capturing on the wmaster0 device
- * captures with 802.11 headers.
- *
- * airmon-ng searches through /sys/class/net for devices named
- * monN, starting with mon0; as soon as one *doesn't* exist,
- * it chooses that as the monitor device name. If the "iw"
- * command exists, it does "iw dev {if} interface add {monif}
- * type monitor", where {monif} is the monitor device. It
- * then (sigh) sleeps .1 second, and then configures the
- * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
- * is a file, it writes {mondev}, without a newline, to that file,
- * and again (sigh) sleeps .1 second, and then iwconfig's that
- * device into monitor mode and configures it up. Otherwise,
- * you can't do monitor mode.
- *
- * All these devices are "glued" together by having the
- * /sys/class/net/{device}/phy80211 links pointing to the same
- * place, so, given a wmaster, wlan, or mon device, you can
- * find the other devices by looking for devices with
- * the same phy80211 link.
- *
- * To turn monitor mode off, delete the monitor interface,
- * either with "iw dev {monif} interface del" or by sending
- * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
- *
- * Note: if you try to create a monitor device named "monN", and
- * there's already a "monN" device, it fails, as least with
- * the netlink interface (which is what iw uses), with a return
- * value of -ENFILE. (Return values are negative errnos.) We
- * could probably use that to find an unused device.
- */
- struct pcap_linux *handlep = handle->priv;
- int err;
- struct iwreq ireq;
- struct iw_priv_args *priv;
- monitor_type montype;
- int i;
- __u32 cmd;
- struct ifreq ifr;
- int oldflags;
- int args[2];
- int channel;
- /*
- * Does this device *support* the Wireless Extensions?
- */
- err = has_wext(sock_fd, device, handle->errbuf);
- if (err <= 0)
- return err; /* either it doesn't or the device doesn't even exist */
- /*
- * Start out assuming we have no private extensions to control
- * radio metadata.
- */
- montype = MONITOR_WEXT;
- cmd = 0;
- /*
- * Try to get all the Wireless Extensions private ioctls
- * supported by this device.
- *
- * First, get the size of the buffer we need, by supplying no
- * buffer and a length of 0. If the device supports private
- * ioctls, it should return E2BIG, with ireq.u.data.length set
- * to the length we need. If it doesn't support them, it should
- * return EOPNOTSUPP.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- ireq.u.data.pointer = (void *)args;
- ireq.u.data.length = 0;
- ireq.u.data.flags = 0;
- if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCGIWPRIV with a zero-length buffer didn't fail!",
- device);
- return PCAP_ERROR;
- }
- if (errno != EOPNOTSUPP) {
- /*
- * OK, it's not as if there are no private ioctls.
- */
- if (errno != E2BIG) {
- /*
- * Failed.
- */
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCGIWPRIV: %s", device,
- pcap_strerror(errno));
- return PCAP_ERROR;
- }
- /*
- * OK, try to get the list of private ioctls.
- */
- priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args));
- if (priv == NULL) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "malloc: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- ireq.u.data.pointer = (void *)priv;
- if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCGIWPRIV: %s", device,
- pcap_strerror(errno));
- free(priv);
- return PCAP_ERROR;
- }
- /*
- * Look for private ioctls to turn monitor mode on or, if
- * monitor mode is on, to set the header type.
- */
- for (i = 0; i < ireq.u.data.length; i++) {
- if (strcmp(priv[i].name, "monitor_type") == 0) {
- /*
- * Hostap driver, use this one.
- * Set monitor mode first.
- * You can set it to 0 to get DLT_IEEE80211,
- * 1 to get DLT_PRISM, 2 to get
- * DLT_IEEE80211_RADIO_AVS, and, with more
- * recent versions of the driver, 3 to get
- * DLT_IEEE80211_RADIO.
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
- break;
- if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
- break;
- if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
- break;
- montype = MONITOR_HOSTAP;
- cmd = priv[i].cmd;
- break;
- }
- if (strcmp(priv[i].name, "set_prismhdr") == 0) {
- /*
- * Prism54 driver, use this one.
- * Set monitor mode first.
- * You can set it to 2 to get DLT_IEEE80211
- * or 3 or get DLT_PRISM.
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
- break;
- if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
- break;
- if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
- break;
- montype = MONITOR_PRISM54;
- cmd = priv[i].cmd;
- break;
- }
- if (strcmp(priv[i].name, "forceprismheader") == 0) {
- /*
- * RT2570 driver, use this one.
- * Do this after turning monitor mode on.
- * You can set it to 1 to get DLT_PRISM or 2
- * to get DLT_IEEE80211.
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
- break;
- if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
- break;
- if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
- break;
- montype = MONITOR_RT2570;
- cmd = priv[i].cmd;
- break;
- }
- if (strcmp(priv[i].name, "forceprism") == 0) {
- /*
- * RT73 driver, use this one.
- * Do this after turning monitor mode on.
- * Its argument is a *string*; you can
- * set it to "1" to get DLT_PRISM or "2"
- * to get DLT_IEEE80211.
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR)
- break;
- if (priv[i].set_args & IW_PRIV_SIZE_FIXED)
- break;
- montype = MONITOR_RT73;
- cmd = priv[i].cmd;
- break;
- }
- if (strcmp(priv[i].name, "prismhdr") == 0) {
- /*
- * One of the RTL8xxx drivers, use this one.
- * It can only be done after monitor mode
- * has been turned on. You can set it to 1
- * to get DLT_PRISM or 0 to get DLT_IEEE80211.
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
- break;
- if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
- break;
- if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
- break;
- montype = MONITOR_RTL8XXX;
- cmd = priv[i].cmd;
- break;
- }
- if (strcmp(priv[i].name, "rfmontx") == 0) {
- /*
- * RT2500 or RT61 driver, use this one.
- * It has one one-byte parameter; set
- * u.data.length to 1 and u.data.pointer to
- * point to the parameter.
- * It doesn't itself turn monitor mode on.
- * You can set it to 1 to allow transmitting
- * in monitor mode(?) and get DLT_IEEE80211,
- * or set it to 0 to disallow transmitting in
- * monitor mode(?) and get DLT_PRISM.
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
- break;
- if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2)
- break;
- montype = MONITOR_RT2500;
- cmd = priv[i].cmd;
- break;
- }
- if (strcmp(priv[i].name, "monitor") == 0) {
- /*
- * Either ACX100 or hostap, use this one.
- * It turns monitor mode on.
- * If it takes two arguments, it's ACX100;
- * the first argument is 1 for DLT_PRISM
- * or 2 for DLT_IEEE80211, and the second
- * argument is the channel on which to
- * run. If it takes one argument, it's
- * HostAP, and the argument is 2 for
- * DLT_IEEE80211 and 3 for DLT_PRISM.
- *
- * If we see this, we don't quit, as this
- * might be a version of the hostap driver
- * that also supports "monitor_type".
- */
- if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
- break;
- if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
- break;
- switch (priv[i].set_args & IW_PRIV_SIZE_MASK) {
- case 1:
- montype = MONITOR_PRISM;
- cmd = priv[i].cmd;
- break;
- case 2:
- montype = MONITOR_ACX100;
- cmd = priv[i].cmd;
- break;
- default:
- break;
- }
- }
- }
- free(priv);
- }
- /*
- * XXX - ipw3945? islism?
- */
- /*
- * Get the old mode.
- */
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) {
- /*
- * We probably won't be able to set the mode, either.
- */
- return PCAP_ERROR_RFMON_NOTSUP;
- }
- /*
- * Is it currently in monitor mode?
- */
- if (ireq.u.mode == IW_MODE_MONITOR) {
- /*
- * Yes. Just leave things as they are.
- * We don't offer multiple link-layer types, as
- * changing the link-layer type out from under
- * somebody else capturing in monitor mode would
- * be considered rude.
- */
- return 1;
- }
- /*
- * No. We have to put the adapter into rfmon mode.
- */
- /*
- * If we haven't already done so, arrange to have
- * "pcap_close_all()" called when we exit.
- */
- if (!pcap_do_addexit(handle)) {
- /*
- * "atexit()" failed; don't put the interface
- * in rfmon mode, just give up.
- */
- return PCAP_ERROR_RFMON_NOTSUP;
- }
- /*
- * Save the old mode.
- */
- handlep->oldmode = ireq.u.mode;
- /*
- * Put the adapter in rfmon mode. How we do this depends
- * on whether we have a special private ioctl or not.
- */
- if (montype == MONITOR_PRISM) {
- /*
- * We have the "monitor" private ioctl, but none of
- * the other private ioctls. Use this, and select
- * the Prism header.
- *
- * If it fails, just fall back on SIOCSIWMODE.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- ireq.u.data.length = 1; /* 1 argument */
- args[0] = 3; /* request Prism header */
- memcpy(ireq.u.name, args, sizeof (int));
- if (ioctl(sock_fd, cmd, &ireq) != -1) {
- /*
- * Success.
- * Note that we have to put the old mode back
- * when we close the device.
- */
- handlep->must_do_on_close |= MUST_CLEAR_RFMON;
- /*
- * Add this to the list of pcaps to close
- * when we exit.
- */
- pcap_add_to_pcaps_to_close(handle);
- return 1;
- }
- /*
- * Failure. Fall back on SIOCSIWMODE.
- */
- }
- /*
- * First, take the interface down if it's up; otherwise, we
- * might get EBUSY.
- */
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't get flags: %s", device, strerror(errno));
- return PCAP_ERROR;
- }
- oldflags = 0;
- if (ifr.ifr_flags & IFF_UP) {
- oldflags = ifr.ifr_flags;
- ifr.ifr_flags &= ~IFF_UP;
- if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't set flags: %s", device, strerror(errno));
- return PCAP_ERROR;
- }
- }
- /*
- * Then turn monitor mode on.
- */
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- ireq.u.mode = IW_MODE_MONITOR;
- if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) {
- /*
- * Scientist, you've failed.
- * Bring the interface back up if we shut it down.
- */
- ifr.ifr_flags = oldflags;
- if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't set flags: %s", device, strerror(errno));
- return PCAP_ERROR;
- }
- return PCAP_ERROR_RFMON_NOTSUP;
- }
- /*
- * XXX - airmon-ng does "iwconfig {if} key off" after setting
- * monitor mode and setting the channel, and then does
- * "iwconfig up".
- */
- /*
- * Now select the appropriate radio header.
- */
- switch (montype) {
- case MONITOR_WEXT:
- /*
- * We don't have any private ioctl to set the header.
- */
- break;
- case MONITOR_HOSTAP:
- /*
- * Try to select the radiotap header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 3; /* request radiotap header */
- memcpy(ireq.u.name, args, sizeof (int));
- if (ioctl(sock_fd, cmd, &ireq) != -1)
- break; /* success */
- /*
- * That failed. Try to select the AVS header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 2; /* request AVS header */
- memcpy(ireq.u.name, args, sizeof (int));
- if (ioctl(sock_fd, cmd, &ireq) != -1)
- break; /* success */
- /*
- * That failed. Try to select the Prism header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 1; /* request Prism header */
- memcpy(ireq.u.name, args, sizeof (int));
- ioctl(sock_fd, cmd, &ireq);
- break;
- case MONITOR_PRISM:
- /*
- * The private ioctl failed.
- */
- break;
- case MONITOR_PRISM54:
- /*
- * Select the Prism header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 3; /* request Prism header */
- memcpy(ireq.u.name, args, sizeof (int));
- ioctl(sock_fd, cmd, &ireq);
- break;
- case MONITOR_ACX100:
- /*
- * Get the current channel.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCGIWFREQ: %s", device,
- pcap_strerror(errno));
- return PCAP_ERROR;
- }
- channel = ireq.u.freq.m;
- /*
- * Select the Prism header, and set the channel to the
- * current value.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 1; /* request Prism header */
- args[1] = channel; /* set channel */
- memcpy(ireq.u.name, args, 2*sizeof (int));
- ioctl(sock_fd, cmd, &ireq);
- break;
- case MONITOR_RT2500:
- /*
- * Disallow transmission - that turns on the
- * Prism header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 0; /* disallow transmitting */
- memcpy(ireq.u.name, args, sizeof (int));
- ioctl(sock_fd, cmd, &ireq);
- break;
- case MONITOR_RT2570:
- /*
- * Force the Prism header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 1; /* request Prism header */
- memcpy(ireq.u.name, args, sizeof (int));
- ioctl(sock_fd, cmd, &ireq);
- break;
- case MONITOR_RT73:
- /*
- * Force the Prism header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- ireq.u.data.length = 1; /* 1 argument */
- ireq.u.data.pointer = "1";
- ireq.u.data.flags = 0;
- ioctl(sock_fd, cmd, &ireq);
- break;
- case MONITOR_RTL8XXX:
- /*
- * Force the Prism header.
- */
- memset(&ireq, 0, sizeof ireq);
- strlcpy(ireq.ifr_ifrn.ifrn_name, device,
- sizeof ireq.ifr_ifrn.ifrn_name);
- args[0] = 1; /* request Prism header */
- memcpy(ireq.u.name, args, sizeof (int));
- ioctl(sock_fd, cmd, &ireq);
- break;
- }
- /*
- * Now bring the interface back up if we brought it down.
- */
- if (oldflags != 0) {
- ifr.ifr_flags = oldflags;
- if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: Can't set flags: %s", device, strerror(errno));
- /*
- * At least try to restore the old mode on the
- * interface.
- */
- if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
- /*
- * Scientist, you've failed.
- */
- fprintf(stderr,
- "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n"
- "Please adjust manually.\n",
- strerror(errno));
- }
- return PCAP_ERROR;
- }
- }
- /*
- * Note that we have to put the old mode back when we
- * close the device.
- */
- handlep->must_do_on_close |= MUST_CLEAR_RFMON;
- /*
- * Add this to the list of pcaps to close when we exit.
- */
- pcap_add_to_pcaps_to_close(handle);
- return 1;
- }
- #endif /* IW_MODE_MONITOR */
- /*
- * Try various mechanisms to enter monitor mode.
- */
- static int
- enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device)
- {
- #if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR)
- int ret;
- #endif
- #ifdef HAVE_LIBNL
- ret = enter_rfmon_mode_mac80211(handle, sock_fd, device);
- if (ret < 0)
- return ret; /* error attempting to do so */
- if (ret == 1)
- return 1; /* success */
- #endif /* HAVE_LIBNL */
- #ifdef IW_MODE_MONITOR
- ret = enter_rfmon_mode_wext(handle, sock_fd, device);
- if (ret < 0)
- return ret; /* error attempting to do so */
- if (ret == 1)
- return 1; /* success */
- #endif /* IW_MODE_MONITOR */
- /*
- * Either none of the mechanisms we know about work or none
- * of those mechanisms are available, so we can't do monitor
- * mode.
- */
- return 0;
- }
- #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
- /*
- * Map SOF_TIMESTAMPING_ values to PCAP_TSTAMP_ values.
- */
- static const struct {
- int soft_timestamping_val;
- int pcap_tstamp_val;
- } sof_ts_type_map[3] = {
- { SOF_TIMESTAMPING_SOFTWARE, PCAP_TSTAMP_HOST },
- { SOF_TIMESTAMPING_SYS_HARDWARE, PCAP_TSTAMP_ADAPTER },
- { SOF_TIMESTAMPING_RAW_HARDWARE, PCAP_TSTAMP_ADAPTER_UNSYNCED }
- };
- #define NUM_SOF_TIMESTAMPING_TYPES (sizeof sof_ts_type_map / sizeof sof_ts_type_map[0])
- static void
- iface_set_default_ts_types(pcap_t *handle)
- {
- int i;
- handle->tstamp_type_count = NUM_SOF_TIMESTAMPING_TYPES;
- handle->tstamp_type_list = malloc(NUM_SOF_TIMESTAMPING_TYPES * sizeof(u_int));
- for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++)
- handle->tstamp_type_list[i] = sof_ts_type_map[i].pcap_tstamp_val;
- }
- #ifdef ETHTOOL_GET_TS_INFO
- /*
- * Get a list of time stamping capabilities.
- */
- static int
- iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf)
- {
- int fd;
- struct ifreq ifr;
- struct ethtool_ts_info info;
- int num_ts_types;
- int i, j;
- /*
- * This doesn't apply to the "any" device; you have to ask
- * specific devices for their capabilities, so just default
- * to saying we support all of them.
- */
- if (strcmp(handle->opt.source, "any") == 0) {
- iface_set_default_ts_types(handle);
- return 0;
- }
- /*
- * Create a socket from which to fetch time stamping capabilities.
- */
- fd = socket(AF_INET, SOCK_DGRAM, 0);
- if (fd < 0) {
- (void)snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "socket for SIOCETHTOOL(ETHTOOL_GET_TS_INFO): %s", pcap_strerror(errno));
- return -1;
- }
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
- memset(&info, 0, sizeof(info));
- info.cmd = ETHTOOL_GET_TS_INFO;
- ifr.ifr_data = (caddr_t)&info;
- if (ioctl(fd, SIOCETHTOOL, &ifr) == -1) {
- close(fd);
- if (errno == EOPNOTSUPP || errno == EINVAL) {
- /*
- * OK, let's just return all the possible time
- * stamping types.
- */
- iface_set_default_ts_types(handle);
- return 0;
- }
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCETHTOOL(ETHTOOL_GET_TS_INFO) ioctl failed: %s", handle->opt.source,
- strerror(errno));
- return -1;
- }
- close(fd);
- num_ts_types = 0;
- for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
- if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val)
- num_ts_types++;
- }
- handle->tstamp_type_count = num_ts_types;
- if (num_ts_types != 0) {
- handle->tstamp_type_list = malloc(num_ts_types * sizeof(u_int));
- for (i = 0, j = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
- if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val) {
- handle->tstamp_type_list[j] = sof_ts_type_map[i].pcap_tstamp_val;
- j++;
- }
- }
- } else
- handle->tstamp_type_list = NULL;
- return 0;
- }
- #else /* ETHTOOL_GET_TS_INFO */
- static int
- iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf _U_)
- {
- /*
- * We don't have an ioctl to use to ask what's supported,
- * so say we support everything.
- */
- iface_set_default_ts_types(handle);
- return 0;
- }
- #endif /* ETHTOOL_GET_TS_INFO */
- #endif /* defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) */
- #ifdef HAVE_PACKET_RING
- /*
- * Find out if we have any form of fragmentation/reassembly offloading.
- *
- * We do so using SIOCETHTOOL checking for various types of offloading;
- * if SIOCETHTOOL isn't defined, or we don't have any #defines for any
- * of the types of offloading, there's nothing we can do to check, so
- * we just say "no, we don't".
- */
- #if defined(SIOCETHTOOL) && (defined(ETHTOOL_GTSO) || defined(ETHTOOL_GUFO) || defined(ETHTOOL_GGSO) || defined(ETHTOOL_GFLAGS) || defined(ETHTOOL_GGRO))
- static int
- iface_ethtool_flag_ioctl(pcap_t *handle, int cmd, const char *cmdname)
- {
- struct ifreq ifr;
- struct ethtool_value eval;
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
- eval.cmd = cmd;
- eval.data = 0;
- ifr.ifr_data = (caddr_t)&eval;
- if (ioctl(handle->fd, SIOCETHTOOL, &ifr) == -1) {
- if (errno == EOPNOTSUPP || errno == EINVAL) {
- /*
- * OK, let's just return 0, which, in our
- * case, either means "no, what we're asking
- * about is not enabled" or "all the flags
- * are clear (i.e., nothing is enabled)".
- */
- return 0;
- }
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "%s: SIOCETHTOOL(%s) ioctl failed: %s", handle->opt.source,
- cmdname, strerror(errno));
- return -1;
- }
- return eval.data;
- }
- static int
- iface_get_offload(pcap_t *handle)
- {
- int ret;
- #ifdef ETHTOOL_GTSO
- ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GTSO, "ETHTOOL_GTSO");
- if (ret == -1)
- return -1;
- if (ret)
- return 1; /* TCP segmentation offloading on */
- #endif
- #ifdef ETHTOOL_GUFO
- ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GUFO, "ETHTOOL_GUFO");
- if (ret == -1)
- return -1;
- if (ret)
- return 1; /* UDP fragmentation offloading on */
- #endif
- #ifdef ETHTOOL_GGSO
- /*
- * XXX - will this cause large unsegmented packets to be
- * handed to PF_PACKET sockets on transmission? If not,
- * this need not be checked.
- */
- ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGSO, "ETHTOOL_GGSO");
- if (ret == -1)
- return -1;
- if (ret)
- return 1; /* generic segmentation offloading on */
- #endif
- #ifdef ETHTOOL_GFLAGS
- ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GFLAGS, "ETHTOOL_GFLAGS");
- if (ret == -1)
- return -1;
- if (ret & ETH_FLAG_LRO)
- return 1; /* large receive offloading on */
- #endif
- #ifdef ETHTOOL_GGRO
- /*
- * XXX - will this cause large reassembled packets to be
- * handed to PF_PACKET sockets on receipt? If not,
- * this need not be checked.
- */
- ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGRO, "ETHTOOL_GGRO");
- if (ret == -1)
- return -1;
- if (ret)
- return 1; /* generic (large) receive offloading on */
- #endif
- return 0;
- }
- #else /* SIOCETHTOOL */
- static int
- iface_get_offload(pcap_t *handle _U_)
- {
- /*
- * XXX - do we need to get this information if we don't
- * have the ethtool ioctls? If so, how do we do that?
- */
- return 0;
- }
- #endif /* SIOCETHTOOL */
- #endif /* HAVE_PACKET_RING */
- #endif /* HAVE_PF_PACKET_SOCKETS */
- /* ===== Functions to interface to the older kernels ================== */
- /*
- * Try to open a packet socket using the old kernel interface.
- * Returns 1 on success and a PCAP_ERROR_ value on an error.
- */
- static int
- activate_old(pcap_t *handle)
- {
- struct pcap_linux *handlep = handle->priv;
- int arptype;
- struct ifreq ifr;
- const char *device = handle->opt.source;
- struct utsname utsname;
- int mtu;
- /* Open the socket */
- handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
- if (handle->fd == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- if (errno == EPERM || errno == EACCES) {
- /*
- * You don't have permission to open the
- * socket.
- */
- return PCAP_ERROR_PERM_DENIED;
- } else {
- /*
- * Other error.
- */
- return PCAP_ERROR;
- }
- }
- /* It worked - we are using the old interface */
- handlep->sock_packet = 1;
- /* ...which means we get the link-layer header. */
- handlep->cooked = 0;
- /* Bind to the given device */
- if (strcmp(device, "any") == 0) {
- strlcpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
- PCAP_ERRBUF_SIZE);
- return PCAP_ERROR;
- }
- if (iface_bind_old(handle->fd, device, handle->errbuf) == -1)
- return PCAP_ERROR;
- /*
- * Try to get the link-layer type.
- */
- arptype = iface_get_arptype(handle->fd, device, handle->errbuf);
- if (arptype < 0)
- return PCAP_ERROR;
- /*
- * Try to find the DLT_ type corresponding to that
- * link-layer type.
- */
- map_arphrd_to_dlt(handle, handle->fd, arptype, device, 0);
- if (handle->linktype == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "unknown arptype %d", arptype);
- return PCAP_ERROR;
- }
- /* Go to promisc mode if requested */
- if (handle->opt.promisc) {
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SIOCGIFFLAGS: %s", pcap_strerror(errno));
- return PCAP_ERROR;
- }
- if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
- /*
- * Promiscuous mode isn't currently on,
- * so turn it on, and remember that
- * we should turn it off when the
- * pcap_t is closed.
- */
- /*
- * If we haven't already done so, arrange
- * to have "pcap_close_all()" called when
- * we exit.
- */
- if (!pcap_do_addexit(handle)) {
- /*
- * "atexit()" failed; don't put
- * the interface in promiscuous
- * mode, just give up.
- */
- return PCAP_ERROR;
- }
- ifr.ifr_flags |= IFF_PROMISC;
- if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "SIOCSIFFLAGS: %s",
- pcap_strerror(errno));
- return PCAP_ERROR;
- }
- handlep->must_do_on_close |= MUST_CLEAR_PROMISC;
- /*
- * Add this to the list of pcaps
- * to close when we exit.
- */
- pcap_add_to_pcaps_to_close(handle);
- }
- }
- /*
- * Compute the buffer size.
- *
- * We're using SOCK_PACKET, so this might be a 2.0[.x]
- * kernel, and might require special handling - check.
- */
- if (uname(&utsname) < 0 ||
- strncmp(utsname.release, "2.0", 3) == 0) {
- /*
- * Either we couldn't find out what kernel release
- * this is, or it's a 2.0[.x] kernel.
- *
- * In the 2.0[.x] kernel, a "recvfrom()" on
- * a SOCK_PACKET socket, with MSG_TRUNC set, will
- * return the number of bytes read, so if we pass
- * a length based on the snapshot length, it'll
- * return the number of bytes from the packet
- * copied to userland, not the actual length
- * of the packet.
- *
- * This means that, for example, the IP dissector
- * in tcpdump will get handed a packet length less
- * than the length in the IP header, and will
- * complain about "truncated-ip".
- *
- * So we don't bother trying to copy from the
- * kernel only the bytes in which we're interested,
- * but instead copy them all, just as the older
- * versions of libpcap for Linux did.
- *
- * The buffer therefore needs to be big enough to
- * hold the largest packet we can get from this
- * device. Unfortunately, we can't get the MRU
- * of the network; we can only get the MTU. The
- * MTU may be too small, in which case a packet larger
- * than the buffer size will be truncated *and* we
- * won't get the actual packet size.
- *
- * However, if the snapshot length is larger than
- * the buffer size based on the MTU, we use the
- * snapshot length as the buffer size, instead;
- * this means that with a sufficiently large snapshot
- * length we won't artificially truncate packets
- * to the MTU-based size.
- *
- * This mess just one of many problems with packet
- * capture on 2.0[.x] kernels; you really want a
- * 2.2[.x] or later kernel if you want packet capture
- * to work well.
- */
- mtu = iface_get_mtu(handle->fd, device, handle->errbuf);
- if (mtu == -1)
- return PCAP_ERROR;
- handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
- if (handle->bufsize < handle->snapshot)
- handle->bufsize = handle->snapshot;
- } else {
- /*
- * This is a 2.2[.x] or later kernel.
- *
- * We can safely pass "recvfrom()" a byte count
- * based on the snapshot length.
- */
- handle->bufsize = handle->snapshot;
- }
- /*
- * Default value for offset to align link-layer payload
- * on a 4-byte boundary.
- */
- handle->offset = 0;
- /*
- * SOCK_PACKET sockets don't supply information from
- * stripped VLAN tags.
- */
- handlep->vlan_offset = -1; /* unknown */
- return 1;
- }
- /*
- * Bind the socket associated with FD to the given device using the
- * interface of the old kernels.
- */
- static int
- iface_bind_old(int fd, const char *device, char *ebuf)
- {
- struct sockaddr saddr;
- int err;
- socklen_t errlen = sizeof(err);
- memset(&saddr, 0, sizeof(saddr));
- strlcpy(saddr.sa_data, device, sizeof(saddr.sa_data));
- if (bind(fd, &saddr, sizeof(saddr)) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(errno));
- return -1;
- }
- /* Any pending errors, e.g., network is down? */
- if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "getsockopt: %s", pcap_strerror(errno));
- return -1;
- }
- if (err > 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(err));
- return -1;
- }
- return 0;
- }
- /* ===== System calls available on all supported kernels ============== */
- /*
- * Query the kernel for the MTU of the given interface.
- */
- static int
- iface_get_mtu(int fd, const char *device, char *ebuf)
- {
- struct ifreq ifr;
- if (!device)
- return BIGGER_THAN_ALL_MTUS;
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "SIOCGIFMTU: %s", pcap_strerror(errno));
- return -1;
- }
- return ifr.ifr_mtu;
- }
- /*
- * Get the hardware type of the given interface as ARPHRD_xxx constant.
- */
- static int
- iface_get_arptype(int fd, const char *device, char *ebuf)
- {
- struct ifreq ifr;
- memset(&ifr, 0, sizeof(ifr));
- strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "SIOCGIFHWADDR: %s", pcap_strerror(errno));
- if (errno == ENODEV) {
- /*
- * No such device.
- */
- return PCAP_ERROR_NO_SUCH_DEVICE;
- }
- return PCAP_ERROR;
- }
- return ifr.ifr_hwaddr.sa_family;
- }
- #ifdef SO_ATTACH_FILTER
- static int
- fix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped)
- {
- struct pcap_linux *handlep = handle->priv;
- size_t prog_size;
- register int i;
- register struct bpf_insn *p;
- struct bpf_insn *f;
- int len;
- /*
- * Make a copy of the filter, and modify that copy if
- * necessary.
- */
- prog_size = sizeof(*handle->fcode.bf_insns) * handle->fcode.bf_len;
- len = handle->fcode.bf_len;
- f = (struct bpf_insn *)malloc(prog_size);
- if (f == NULL) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "malloc: %s", pcap_strerror(errno));
- return -1;
- }
- memcpy(f, handle->fcode.bf_insns, prog_size);
- fcode->len = len;
- fcode->filter = (struct sock_filter *) f;
- for (i = 0; i < len; ++i) {
- p = &f[i];
- /*
- * What type of instruction is this?
- */
- switch (BPF_CLASS(p->code)) {
- case BPF_RET:
- /*
- * It's a return instruction; are we capturing
- * in memory-mapped mode?
- */
- if (!is_mmapped) {
- /*
- * No; is the snapshot length a constant,
- * rather than the contents of the
- * accumulator?
- */
- if (BPF_MODE(p->code) == BPF_K) {
- /*
- * Yes - if the value to be returned,
- * i.e. the snapshot length, is
- * anything other than 0, make it
- * MAXIMUM_SNAPLEN, so that the packet
- * is truncated by "recvfrom()",
- * not by the filter.
- *
- * XXX - there's nothing we can
- * easily do if it's getting the
- * value from the accumulator; we'd
- * have to insert code to force
- * non-zero values to be
- * MAXIMUM_SNAPLEN.
- */
- if (p->k != 0)
- p->k = MAXIMUM_SNAPLEN;
- }
- }
- break;
- case BPF_LD:
- case BPF_LDX:
- /*
- * It's a load instruction; is it loading
- * from the packet?
- */
- switch (BPF_MODE(p->code)) {
- case BPF_ABS:
- case BPF_IND:
- case BPF_MSH:
- /*
- * Yes; are we in cooked mode?
- */
- if (handlep->cooked) {
- /*
- * Yes, so we need to fix this
- * instruction.
- */
- if (fix_offset(p) < 0) {
- /*
- * We failed to do so.
- * Return 0, so our caller
- * knows to punt to userland.
- */
- return 0;
- }
- }
- break;
- }
- break;
- }
- }
- return 1; /* we succeeded */
- }
- static int
- fix_offset(struct bpf_insn *p)
- {
- /*
- * What's the offset?
- */
- if (p->k >= SLL_HDR_LEN) {
- /*
- * It's within the link-layer payload; that starts at an
- * offset of 0, as far as the kernel packet filter is
- * concerned, so subtract the length of the link-layer
- * header.
- */
- p->k -= SLL_HDR_LEN;
- } else if (p->k == 0) {
- /*
- * It's the packet type field; map it to the special magic
- * kernel offset for that field.
- */
- p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
- } else if (p->k == 14) {
- /*
- * It's the protocol field; map it to the special magic
- * kernel offset for that field.
- */
- p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
- } else if ((bpf_int32)(p->k) > 0) {
- /*
- * It's within the header, but it's not one of those
- * fields; we can't do that in the kernel, so punt
- * to userland.
- */
- return -1;
- }
- return 0;
- }
- static int
- set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode)
- {
- int total_filter_on = 0;
- int save_mode;
- int ret;
- int save_errno;
- /*
- * The socket filter code doesn't discard all packets queued
- * up on the socket when the filter is changed; this means
- * that packets that don't match the new filter may show up
- * after the new filter is put onto the socket, if those
- * packets haven't yet been read.
- *
- * This means, for example, that if you do a tcpdump capture
- * with a filter, the first few packets in the capture might
- * be packets that wouldn't have passed the filter.
- *
- * We therefore discard all packets queued up on the socket
- * when setting a kernel filter. (This isn't an issue for
- * userland filters, as the userland filtering is done after
- * packets are queued up.)
- *
- * To flush those packets, we put the socket in read-only mode,
- * and read packets from the socket until there are no more to
- * read.
- *
- * In order to keep that from being an infinite loop - i.e.,
- * to keep more packets from arriving while we're draining
- * the queue - we put the "total filter", which is a filter
- * that rejects all packets, onto the socket before draining
- * the queue.
- *
- * This code deliberately ignores any errors, so that you may
- * get bogus packets if an error occurs, rather than having
- * the filtering done in userland even if it could have been
- * done in the kernel.
- */
- if (setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
- &total_fcode, sizeof(total_fcode)) == 0) {
- char drain[1];
- /*
- * Note that we've put the total filter onto the socket.
- */
- total_filter_on = 1;
- /*
- * Save the socket's current mode, and put it in
- * non-blocking mode; we drain it by reading packets
- * until we get an error (which is normally a
- * "nothing more to be read" error).
- */
- save_mode = fcntl(handle->fd, F_GETFL, 0);
- if (save_mode == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't get FD flags when changing filter: %s",
- pcap_strerror(errno));
- return -2;
- }
- if (fcntl(handle->fd, F_SETFL, save_mode | O_NONBLOCK) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't set nonblocking mode when changing filter: %s",
- pcap_strerror(errno));
- return -2;
- }
- while (recv(handle->fd, &drain, sizeof drain, MSG_TRUNC) >= 0)
- ;
- save_errno = errno;
- if (save_errno != EAGAIN) {
- /*
- * Fatal error.
- *
- * If we can't restore the mode or reset the
- * kernel filter, there's nothing we can do.
- */
- (void)fcntl(handle->fd, F_SETFL, save_mode);
- (void)reset_kernel_filter(handle);
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "recv failed when changing filter: %s",
- pcap_strerror(save_errno));
- return -2;
- }
- if (fcntl(handle->fd, F_SETFL, save_mode) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't restore FD flags when changing filter: %s",
- pcap_strerror(save_errno));
- return -2;
- }
- }
- /*
- * Now attach the new filter.
- */
- ret = setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
- fcode, sizeof(*fcode));
- if (ret == -1 && total_filter_on) {
- /*
- * Well, we couldn't set that filter on the socket,
- * but we could set the total filter on the socket.
- *
- * This could, for example, mean that the filter was
- * too big to put into the kernel, so we'll have to
- * filter in userland; in any case, we'll be doing
- * filtering in userland, so we need to remove the
- * total filter so we see packets.
- */
- save_errno = errno;
- /*
- * If this fails, we're really screwed; we have the
- * total filter on the socket, and it won't come off.
- * Report it as a fatal error.
- */
- if (reset_kernel_filter(handle) == -1) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "can't remove kernel total filter: %s",
- pcap_strerror(errno));
- return -2; /* fatal error */
- }
- errno = save_errno;
- }
- return ret;
- }
- static int
- reset_kernel_filter(pcap_t *handle)
- {
- /*
- * setsockopt() barfs unless it get a dummy parameter.
- * valgrind whines unless the value is initialized,
- * as it has no idea that setsockopt() ignores its
- * parameter.
- */
- int dummy = 0;
- return setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER,
- &dummy, sizeof(dummy));
- }
- #endif