/nsock/src/engine_select.c
C | 393 lines | 222 code | 81 blank | 90 comment | 58 complexity | 1e24cde125ef3a606b7f16d7d97d8386 MD5 | raw file
Possible License(s): BSD-3-Clause, GPL-2.0, Apache-2.0, LGPL-2.0, LGPL-2.1, MIT
- /***************************************************************************
- * engine_select.c -- select(2) based IO engine. *
- * *
- ***********************IMPORTANT NSOCK LICENSE TERMS***********************
- * *
- * The nsock parallel socket event library is (C) 1999-2015 Insecure.Com *
- * LLC This library is free software; you may redistribute and/or *
- * modify it under the terms of the GNU General Public License as *
- * published by the Free Software Foundation; Version 2. This guarantees *
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- * may be willing to sell alternative licenses (contact *
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- * *
- * As a special exception to the GPL terms, Insecure.Com LLC grants *
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- * OpenSSL library which is distributed under a license identical to that *
- * listed in the included docs/licenses/OpenSSL.txt file, and distribute *
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- * right to know exactly what a program is going to do before they run it. *
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- * Source code also allows you to port Nmap to new platforms, fix bugs, *
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- * code. Nmap will always be available Open Source, but this is important *
- * because the inability to relicense code has caused devastating problems *
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- * This program is distributed in the hope that it will be useful, but *
- * WITHOUT ANY WARRANTY; without even the implied warranty of *
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- * General Public License v2.0 for more details *
- * (http://www.gnu.org/licenses/gpl-2.0.html). *
- * *
- ***************************************************************************/
- /* $Id$ */
- #ifndef WIN32
- #include <sys/select.h>
- #endif
- #include <errno.h>
- #include "nsock_internal.h"
- #include "nsock_log.h"
- #if HAVE_PCAP
- #include "nsock_pcap.h"
- #endif
- /* --- ENGINE INTERFACE PROTOTYPES --- */
- static int select_init(struct npool *nsp);
- static void select_destroy(struct npool *nsp);
- static int select_iod_register(struct npool *nsp, struct niod *iod, int ev);
- static int select_iod_unregister(struct npool *nsp, struct niod *iod);
- static int select_iod_modify(struct npool *nsp, struct niod *iod, int ev_set, int ev_clr);
- static int select_loop(struct npool *nsp, int msec_timeout);
- /* ---- ENGINE DEFINITION ---- */
- struct io_engine engine_select = {
- "select",
- select_init,
- select_destroy,
- select_iod_register,
- select_iod_unregister,
- select_iod_modify,
- select_loop
- };
- /* --- INTERNAL PROTOTYPES --- */
- static void iterate_through_event_lists(struct npool *nsp);
- /* defined in nsock_core.c */
- void process_event(struct npool *nsp, gh_list_t *evlist, struct nevent *nse, int ev);
- void process_iod_events(struct npool *nsp, struct niod *nsi, int ev);
- void process_expired_events(struct npool *nsp);
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- int pcap_read_on_nonselect(struct npool *nsp);
- #endif
- #endif
- /* defined in nsock_event.c */
- void update_first_events(struct nevent *nse);
- extern struct timeval nsock_tod;
- /*
- * Engine specific data structure
- */
- struct select_engine_info {
- /* Descriptors which have pending READ events */
- fd_set fds_master_r;
- /* Descriptors we are trying to WRITE to */
- fd_set fds_master_w;
- /* Looking for exceptional events -- used with connect */
- fd_set fds_master_x;
- /* For keeping track of the select results */
- fd_set fds_results_r, fds_results_w, fds_results_x;
- /* The highest sd we have set in any of our fd_set's (max_sd + 1 is used in
- * select() calls). Note that it can be -1, when there are no valid sockets */
- int max_sd;
- };
- int select_init(struct npool *nsp) {
- struct select_engine_info *sinfo;
- sinfo = (struct select_engine_info *)safe_malloc(sizeof(struct select_engine_info));
- FD_ZERO(&sinfo->fds_master_r);
- FD_ZERO(&sinfo->fds_master_w);
- FD_ZERO(&sinfo->fds_master_x);
- sinfo->max_sd = -1;
- nsp->engine_data = (void *)sinfo;
- return 1;
- }
- void select_destroy(struct npool *nsp) {
- assert(nsp->engine_data != NULL);
- free(nsp->engine_data);
- }
- int select_iod_register(struct npool *nsp, struct niod *iod, int ev) {
- assert(!IOD_PROPGET(iod, IOD_REGISTERED));
- iod->watched_events = ev;
- select_iod_modify(nsp, iod, ev, EV_NONE);
- IOD_PROPSET(iod, IOD_REGISTERED);
- return 1;
- }
- int select_iod_unregister(struct npool *nsp, struct niod *iod) {
- struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
- iod->watched_events = EV_NONE;
- /* some IODs can be unregistered here if they're associated to an event that was
- * immediately completed */
- if (IOD_PROPGET(iod, IOD_REGISTERED)) {
- #if HAVE_PCAP
- if (iod->pcap) {
- int sd = ((mspcap *)iod->pcap)->pcap_desc;
- if (sd >= 0) {
- checked_fd_clr(sd, &sinfo->fds_master_r);
- checked_fd_clr(sd, &sinfo->fds_results_r);
- }
- } else
- #endif
- {
- checked_fd_clr(iod->sd, &sinfo->fds_master_r);
- checked_fd_clr(iod->sd, &sinfo->fds_master_w);
- checked_fd_clr(iod->sd, &sinfo->fds_master_x);
- checked_fd_clr(iod->sd, &sinfo->fds_results_r);
- checked_fd_clr(iod->sd, &sinfo->fds_results_w);
- checked_fd_clr(iod->sd, &sinfo->fds_results_x);
- }
- if (sinfo->max_sd == iod->sd)
- sinfo->max_sd--;
- IOD_PROPCLR(iod, IOD_REGISTERED);
- }
- return 1;
- }
- int select_iod_modify(struct npool *nsp, struct niod *iod, int ev_set, int ev_clr) {
- int sd;
- struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
- assert((ev_set & ev_clr) == 0);
- iod->watched_events |= ev_set;
- iod->watched_events &= ~ev_clr;
- sd = nsock_iod_get_sd(iod);
- /* -- set events -- */
- if (ev_set & EV_READ)
- checked_fd_set(sd, &sinfo->fds_master_r);
- if (ev_set & EV_WRITE)
- checked_fd_set(sd, &sinfo->fds_master_w);
- if (ev_set & EV_EXCEPT)
- checked_fd_set(sd, &sinfo->fds_master_x);
- /* -- clear events -- */
- if (ev_clr & EV_READ)
- checked_fd_clr(sd, &sinfo->fds_master_r);
- if (ev_clr & EV_WRITE)
- checked_fd_clr(sd, &sinfo->fds_master_w);
- if (ev_clr & EV_EXCEPT)
- checked_fd_clr(sd, &sinfo->fds_master_x);
- /* -- update max_sd -- */
- if (ev_set != EV_NONE)
- sinfo->max_sd = MAX(sinfo->max_sd,sd);
- else if (ev_clr != EV_NONE && iod->events_pending == 1 && (sinfo->max_sd == sd))
- sinfo->max_sd--;
- return 1;
- }
- int select_loop(struct npool *nsp, int msec_timeout) {
- int results_left = 0;
- int event_msecs; /* msecs before an event goes off */
- int combined_msecs;
- int sock_err = 0;
- struct timeval select_tv;
- struct timeval *select_tv_p;
- struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
- assert(msec_timeout >= -1);
- if (nsp->events_pending == 0)
- return 0; /* No need to wait on 0 events ... */
- do {
- struct nevent *nse;
- nsock_log_debug_all("wait for events");
- nse = next_expirable_event(nsp);
- if (!nse)
- event_msecs = -1; /* None of the events specified a timeout */
- else
- event_msecs = MAX(0, TIMEVAL_MSEC_SUBTRACT(nse->timeout, nsock_tod));
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- /* Force a low timeout when capturing packets on systems where
- * the pcap descriptor is not select()able. */
- if (gh_list_count(&nsp->pcap_read_events))
- if (event_msecs > PCAP_POLL_INTERVAL)
- event_msecs = PCAP_POLL_INTERVAL;
- #endif
- #endif
- /* We cast to unsigned because we want -1 to be very high (since it means no
- * timeout) */
- combined_msecs = MIN((unsigned)event_msecs, (unsigned)msec_timeout);
- /* Set up the timeval pointer we will give to select() */
- memset(&select_tv, 0, sizeof(select_tv));
- if (combined_msecs > 0) {
- select_tv.tv_sec = combined_msecs / 1000;
- select_tv.tv_usec = (combined_msecs % 1000) * 1000;
- select_tv_p = &select_tv;
- } else if (combined_msecs == 0) {
- /* we want the tv_sec and tv_usec to be zero but they already are from bzero */
- select_tv_p = &select_tv;
- } else {
- assert(combined_msecs == -1);
- select_tv_p = NULL;
- }
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- /* do non-blocking read on pcap devices that doesn't support select()
- * If there is anything read, just leave this loop. */
- if (pcap_read_on_nonselect(nsp)) {
- /* okay, something was read. */
- } else
- #endif
- #endif
- {
- /* Set up the descriptors for select */
- sinfo->fds_results_r = sinfo->fds_master_r;
- sinfo->fds_results_w = sinfo->fds_master_w;
- sinfo->fds_results_x = sinfo->fds_master_x;
- results_left = fselect(sinfo->max_sd + 1, &sinfo->fds_results_r,
- &sinfo->fds_results_w, &sinfo->fds_results_x, select_tv_p);
- if (results_left == -1)
- sock_err = socket_errno();
- }
- gettimeofday(&nsock_tod, NULL); /* Due to select delay */
- } while (results_left == -1 && sock_err == EINTR); /* repeat only if signal occurred */
- if (results_left == -1 && sock_err != EINTR) {
- nsock_log_error("nsock_loop error %d: %s", sock_err, socket_strerror(sock_err));
- nsp->errnum = sock_err;
- return -1;
- }
- iterate_through_event_lists(nsp);
- return 1;
- }
- /* ---- INTERNAL FUNCTIONS ---- */
- static inline int get_evmask(const struct npool *nsp, const struct niod *nsi) {
- struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
- int sd, evmask;
- evmask = EV_NONE;
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- if (nsi->pcap) {
- /* Always assume readable for a non-blocking read. We can't check checked_fd_isset
- because we don't have a pcap_desc. */
- evmask |= EV_READ;
- return evmask;
- }
- #endif
- #endif
- #if HAVE_PCAP
- if (nsi->pcap)
- sd = ((mspcap *)nsi->pcap)->pcap_desc;
- else
- #endif
- sd = nsi->sd;
- assert(sd >= 0);
- if (checked_fd_isset(sd, &sinfo->fds_results_r))
- evmask |= EV_READ;
- if (checked_fd_isset(sd, &sinfo->fds_results_w))
- evmask |= EV_WRITE;
- if (checked_fd_isset(sd, &sinfo->fds_results_x))
- evmask |= EV_EXCEPT;
- return evmask;
- }
- /* Iterate through all the event lists (such as connect_events, read_events,
- * timer_events, etc) and take action for those that have completed (due to
- * timeout, i/o, etc) */
- void iterate_through_event_lists(struct npool *nsp) {
- gh_lnode_t *current, *next, *last;
- last = gh_list_last_elem(&nsp->active_iods);
- for (current = gh_list_first_elem(&nsp->active_iods);
- current != NULL && gh_lnode_prev(current) != last;
- current = next) {
- struct niod *nsi = container_of(current, struct niod, nodeq);
- if (nsi->state != NSIOD_STATE_DELETED && nsi->events_pending)
- process_iod_events(nsp, nsi, get_evmask(nsp, nsi));
- next = gh_lnode_next(current);
- if (nsi->state == NSIOD_STATE_DELETED) {
- gh_list_remove(&nsp->active_iods, current);
- gh_list_prepend(&nsp->free_iods, current);
- }
- }
- /* iterate through timers and expired events */
- process_expired_events(nsp);
- }