/arch/um/os-Linux/drivers/tuntap_user.c

  1/* 
  2 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include <stdio.h>
  7#include <unistd.h>
  8#include <errno.h>
  9#include <string.h>
 10#include <linux/if_tun.h>
 11#include <net/if.h>
 12#include <sys/ioctl.h>
 13#include <sys/socket.h>
 14#include <sys/wait.h>
 15#include <sys/uio.h>
 16#include "kern_constants.h"
 17#include "kern_util.h"
 18#include "os.h"
 19#include "tuntap.h"
 20#include "user.h"
 21
 22static int tuntap_user_init(void *data, void *dev)
 23{
 24	struct tuntap_data *pri = data;
 25
 26	pri->dev = dev;
 27	return 0;
 28}
 29
 30static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,
 31			    void *data)
 32{
 33	struct tuntap_data *pri = data;
 34
 35	tap_check_ips(pri->gate_addr, addr);
 36	if ((pri->fd == -1) || pri->fixed_config)
 37		return;
 38	open_addr(addr, netmask, pri->dev_name);
 39}
 40
 41static void tuntap_del_addr(unsigned char *addr, unsigned char *netmask,
 42			    void *data)
 43{
 44	struct tuntap_data *pri = data;
 45
 46	if ((pri->fd == -1) || pri->fixed_config)
 47		return;
 48	close_addr(addr, netmask, pri->dev_name);
 49}
 50
 51struct tuntap_pre_exec_data {
 52	int stdout;
 53	int close_me;
 54};
 55
 56static void tuntap_pre_exec(void *arg)
 57{
 58	struct tuntap_pre_exec_data *data = arg;
 59
 60	dup2(data->stdout, 1);
 61	close(data->close_me);
 62}
 63
 64static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
 65			     char *buffer, int buffer_len, int *used_out)
 66{
 67	struct tuntap_pre_exec_data data;
 68	char version_buf[sizeof("nnnnn\0")];
 69	char *argv[] = { "uml_net", version_buf, "tuntap", "up", gate,
 70			 NULL };
 71	char buf[CMSG_SPACE(sizeof(*fd_out))];
 72	struct msghdr msg;
 73	struct cmsghdr *cmsg;
 74	struct iovec iov;
 75	int pid, n, err;
 76
 77	sprintf(version_buf, "%d", UML_NET_VERSION);
 78
 79	data.stdout = remote;
 80	data.close_me = me;
 81
 82	pid = run_helper(tuntap_pre_exec, &data, argv);
 83
 84	if (pid < 0)
 85		return -pid;
 86
 87	close(remote);
 88
 89	msg.msg_name = NULL;
 90	msg.msg_namelen = 0;
 91	if (buffer != NULL) {
 92		iov = ((struct iovec) { buffer, buffer_len });
 93		msg.msg_iov = &iov;
 94		msg.msg_iovlen = 1;
 95	}
 96	else {
 97		msg.msg_iov = NULL;
 98		msg.msg_iovlen = 0;
 99	}
100	msg.msg_control = buf;
101	msg.msg_controllen = sizeof(buf);
102	msg.msg_flags = 0;
103	n = recvmsg(me, &msg, 0);
104	*used_out = n;
105	if (n < 0) {
106		err = -errno;
107		printk(UM_KERN_ERR "tuntap_open_tramp : recvmsg failed - "
108		       "errno = %d\n", errno);
109		return err;
110	}
111	helper_wait(pid);
112
113	cmsg = CMSG_FIRSTHDR(&msg);
114	if (cmsg == NULL) {
115		printk(UM_KERN_ERR "tuntap_open_tramp : didn't receive a "
116		       "message\n");
117		return -EINVAL;
118	}
119	if ((cmsg->cmsg_level != SOL_SOCKET) ||
120	   (cmsg->cmsg_type != SCM_RIGHTS)) {
121		printk(UM_KERN_ERR "tuntap_open_tramp : didn't receive a "
122		       "descriptor\n");
123		return -EINVAL;
124	}
125	*fd_out = ((int *) CMSG_DATA(cmsg))[0];
126	os_set_exec_close(*fd_out);
127	return 0;
128}
129
130static int tuntap_open(void *data)
131{
132	struct ifreq ifr;
133	struct tuntap_data *pri = data;
134	char *output, *buffer;
135	int err, fds[2], len, used;
136
137	err = tap_open_common(pri->dev, pri->gate_addr);
138	if (err < 0)
139		return err;
140
141	if (pri->fixed_config) {
142		pri->fd = os_open_file("/dev/net/tun",
143				       of_cloexec(of_rdwr(OPENFLAGS())), 0);
144		if (pri->fd < 0) {
145			printk(UM_KERN_ERR "Failed to open /dev/net/tun, "
146			       "err = %d\n", -pri->fd);
147			return pri->fd;
148		}
149		memset(&ifr, 0, sizeof(ifr));
150		ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
151		strlcpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name));
152		if (ioctl(pri->fd, TUNSETIFF, &ifr) < 0) {
153			err = -errno;
154			printk(UM_KERN_ERR "TUNSETIFF failed, errno = %d\n",
155			       errno);
156			close(pri->fd);
157			return err;
158		}
159	}
160	else {
161		err = socketpair(AF_UNIX, SOCK_DGRAM, 0, fds);
162		if (err) {
163			err = -errno;
164			printk(UM_KERN_ERR "tuntap_open : socketpair failed - "
165			       "errno = %d\n", errno);
166			return err;
167		}
168
169		buffer = get_output_buffer(&len);
170		if (buffer != NULL)
171			len--;
172		used = 0;
173
174		err = tuntap_open_tramp(pri->gate_addr, &pri->fd, fds[0],
175					fds[1], buffer, len, &used);
176
177		output = buffer;
178		if (err < 0) {
179			printk("%s", output);
180			free_output_buffer(buffer);
181			printk(UM_KERN_ERR "tuntap_open_tramp failed - "
182			       "err = %d\n", -err);
183			return err;
184		}
185
186		pri->dev_name = uml_strdup(buffer);
187		output += IFNAMSIZ;
188		printk("%s", output);
189		free_output_buffer(buffer);
190
191		close(fds[0]);
192		iter_addresses(pri->dev, open_addr, pri->dev_name);
193	}
194
195	return pri->fd;
196}
197
198static void tuntap_close(int fd, void *data)
199{
200	struct tuntap_data *pri = data;
201
202	if (!pri->fixed_config)
203		iter_addresses(pri->dev, close_addr, pri->dev_name);
204	close(fd);
205	pri->fd = -1;
206}
207
208const struct net_user_info tuntap_user_info = {
209	.init		= tuntap_user_init,
210	.open		= tuntap_open,
211	.close	 	= tuntap_close,
212	.remove	 	= NULL,
213	.add_address	= tuntap_add_addr,
214	.delete_address = tuntap_del_addr,
215	.mtu		= ETH_MAX_PACKET,
216	.max_packet	= ETH_MAX_PACKET + ETH_HEADER_OTHER,
217};