/*************************************************************************** * engine_epoll.c -- epoll(7) 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 * * your right to use, modify, and redistribute this software under certain * * conditions. If this license is unacceptable to you, Insecure.Com LLC * * may be willing to sell alternative licenses (contact * * sales@insecure.com ). * * * * As a special exception to the GPL terms, Insecure.Com LLC grants * * permission to link the code of this program with any version of the * * OpenSSL library which is distributed under a license identical to that * * listed in the included docs/licenses/OpenSSL.txt file, and distribute * * linked combinations including the two. You must obey the GNU GPL in all * * respects for all of the code used other than OpenSSL. If you modify * * this file, you may extend this exception to your version of the file, * * but you are not obligated to do so. * * * * If you received these files with a written license agreement stating * * terms other than the (GPL) terms above, then that alternative license * * agreement takes precedence over this comment. * * * * Source is provided to this software because we believe users have a * * right to know exactly what a program is going to do before they run it. * * This also allows you to audit the software for security holes. * * * * Source code also allows you to port Nmap to new platforms, fix bugs, * * and add new features. You are highly encouraged to send your changes * * to the dev@nmap.org mailing list for possible incorporation into the * * main distribution. By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, or checking them into the Nmap * * source code repository, it is understood (unless you specify otherwise) * * that you are offering the Nmap Project (Insecure.Com LLC) the * * unlimited, non-exclusive right to reuse, modify, and relicense the * * code. Nmap will always be available Open Source, but this is important * * because the inability to relicense code has caused devastating problems * * for other Free Software projects (such as KDE and NASM). We also * * occasionally relicense the code to third parties as discussed above. * * If you wish to specify special license conditions of your * * contributions, just say so when you send them. * * * * This program is distributed in the hope that it will be useful, but * * WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * * General Public License v2.0 for more details * * (http://www.gnu.org/licenses/gpl-2.0.html). * * * ***************************************************************************/ /* $Id$ */ #ifdef HAVE_CONFIG_H #include "nsock_config.h" #endif #if HAVE_EPOLL #include #include #include "nsock_internal.h" #include "nsock_log.h" #if HAVE_PCAP #include "nsock_pcap.h" #endif #define INITIAL_EV_COUNT 128 #define EPOLL_R_FLAGS (EPOLLIN | EPOLLPRI) #define EPOLL_W_FLAGS EPOLLOUT #ifdef EPOLLRDHUP #define EPOLL_X_FLAGS (EPOLLERR | EPOLLRDHUP| EPOLLHUP) #else /* EPOLLRDHUP was introduced later and might be unavailable on older systems. */ #define EPOLL_X_FLAGS (EPOLLERR | EPOLLHUP) #endif /* EPOLLRDHUP */ /* --- ENGINE INTERFACE PROTOTYPES --- */ static int epoll_init(struct npool *nsp); static void epoll_destroy(struct npool *nsp); static int epoll_iod_register(struct npool *nsp, struct niod *iod, int ev); static int epoll_iod_unregister(struct npool *nsp, struct niod *iod); static int epoll_iod_modify(struct npool *nsp, struct niod *iod, int ev_set, int ev_clr); static int epoll_loop(struct npool *nsp, int msec_timeout); /* ---- ENGINE DEFINITION ---- */ struct io_engine engine_epoll = { "epoll", epoll_init, epoll_destroy, epoll_iod_register, epoll_iod_unregister, epoll_iod_modify, epoll_loop }; /* --- INTERNAL PROTOTYPES --- */ static void iterate_through_event_lists(struct npool *nsp, int evcount); /* defined in nsock_core.c */ void process_iod_events(struct npool *nsp, struct niod *nsi, int ev); void process_event(struct npool *nsp, gh_list_t *evlist, struct nevent *nse, 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 epoll_engine_info { /* file descriptor corresponding to our epoll instance */ int epfd; /* number of epoll_events we can deal with */ int evlen; /* list of epoll events, resized if necessary (when polling over large numbers of IODs) */ struct epoll_event *events; }; int epoll_init(struct npool *nsp) { struct epoll_engine_info *einfo; einfo = (struct epoll_engine_info *)safe_malloc(sizeof(struct epoll_engine_info)); einfo->epfd = epoll_create(10); /* argument is ignored */ einfo->evlen = INITIAL_EV_COUNT; einfo->events = (struct epoll_event *)safe_malloc(einfo->evlen * sizeof(struct epoll_event)); nsp->engine_data = (void *)einfo; return 1; } void epoll_destroy(struct npool *nsp) { struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data; assert(einfo != NULL); close(einfo->epfd); free(einfo->events); free(einfo); } int epoll_iod_register(struct npool *nsp, struct niod *iod, int ev) { int sd; struct epoll_event epev; struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data; assert(!IOD_PROPGET(iod, IOD_REGISTERED)); iod->watched_events = ev; memset(&epev, 0x00, sizeof(struct epoll_event)); epev.events = EPOLLET; epev.data.ptr = (void *)iod; if (ev & EV_READ) epev.events |= EPOLL_R_FLAGS; if (ev & EV_WRITE) epev.events |= EPOLL_W_FLAGS; if (ev & EV_EXCEPT) epev.events |= EPOLL_X_FLAGS; sd = nsi_getsd(iod); if (epoll_ctl(einfo->epfd, EPOLL_CTL_ADD, sd, &epev) < 0) fatal("Unable to register IOD #%lu: %s", iod->id, strerror(errno)); IOD_PROPSET(iod, IOD_REGISTERED); return 1; } int epoll_iod_unregister(struct npool *nsp, struct niod *iod) { 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)) { struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data; int sd; sd = nsi_getsd(iod); epoll_ctl(einfo->epfd, EPOLL_CTL_DEL, sd, NULL); IOD_PROPCLR(iod, IOD_REGISTERED); } return 1; } int epoll_iod_modify(struct npool *nsp, struct niod *iod, int ev_set, int ev_clr) { int sd; struct epoll_event epev; int new_events; struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data; assert((ev_set & ev_clr) == 0); assert(IOD_PROPGET(iod, IOD_REGISTERED)); memset(&epev, 0x00, sizeof(struct epoll_event)); epev.events = EPOLLET; epev.data.ptr = (void *)iod; new_events = iod->watched_events; new_events |= ev_set; new_events &= ~ev_clr; if (new_events == iod->watched_events) return 1; /* nothing to do */ iod->watched_events = new_events; /* regenerate the current set of events for this IOD */ if (iod->watched_events & EV_READ) epev.events |= EPOLL_R_FLAGS; if (iod->watched_events & EV_WRITE) epev.events |= EPOLL_W_FLAGS; if (iod->watched_events & EV_EXCEPT) epev.events |= EPOLL_X_FLAGS; sd = nsi_getsd(iod); if (epoll_ctl(einfo->epfd, EPOLL_CTL_MOD, sd, &epev) < 0) fatal("Unable to update events for IOD #%lu: %s", iod->id, strerror(errno)); return 1; } int epoll_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; unsigned int iod_count; struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data; assert(msec_timeout >= -1); if (nsp->events_pending == 0) return 0; /* No need to wait on 0 events ... */ iod_count = gh_list_count(&nsp->active_iods); if (iod_count > einfo->evlen) { einfo->evlen = iod_count * 2; einfo->events = (struct epoll_event *)safe_realloc(einfo->events, einfo->evlen * sizeof(struct epoll_event)); } do { struct nevent *nse; nsock_log_debug_all(nsp, "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) > 0) 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); #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 { results_left = epoll_wait(einfo->epfd, einfo->events, einfo->evlen, combined_msecs); if (results_left == -1) sock_err = socket_errno(); } gettimeofday(&nsock_tod, NULL); /* Due to epoll delay */ } while (results_left == -1 && sock_err == EINTR); /* repeat only if signal occurred */ if (results_left == -1 && sock_err != EINTR) { nsock_log_error(nsp, "nsock_loop error %d: %s", sock_err, socket_strerror(sock_err)); nsp->errnum = sock_err; return -1; } iterate_through_event_lists(nsp, results_left); return 1; } /* ---- INTERNAL FUNCTIONS ---- */ static inline int get_evmask(struct epoll_engine_info *einfo, int n) { int evmask = EV_NONE; if (einfo->events[n].events & EPOLL_R_FLAGS) evmask |= EV_READ; if (einfo->events[n].events & EPOLL_W_FLAGS) evmask |= EV_WRITE; if (einfo->events[n].events & EPOLL_X_FLAGS) evmask |= (EV_READ | EV_WRITE | 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, int evcount) { struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data; int n; for (n = 0; n < evcount; n++) { struct niod *nsi = (struct niod *)einfo->events[n].data.ptr; assert(nsi); /* process all the pending events for this IOD */ process_iod_events(nsp, nsi, get_evmask(einfo, n)); if (nsi->state == NSIOD_STATE_DELETED) { gh_list_remove(&nsp->active_iods, &nsi->nodeq); gh_list_prepend(&nsp->free_iods, &nsi->nodeq); } } /* iterate through timers and expired events */ process_expired_events(nsp); } #endif /* HAVE_EPOLL */