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nmap/nsock/src/engine_epoll.c

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/***************************************************************************
* engine_epoll.c -- epoll(7) based IO engine. *
* *
***********************IMPORTANT NSOCK LICENSE TERMS***********************
* *
* The nsock parallel socket event library is (C) 1999-2012 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 (none *
* have been found so far). *
* *
* 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 <sys/epoll.h>
#include <errno.h>
#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(mspool *nsp);
static void epoll_destroy(mspool *nsp);
static int epoll_iod_register(mspool *nsp, msiod *iod, int ev);
static int epoll_iod_unregister(mspool *nsp, msiod *iod);
static int epoll_iod_modify(mspool *nsp, msiod *iod, int ev_set, int ev_clr);
static int epoll_loop(mspool *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(mspool *nsp, int evcount);
/* defined in nsock_core.c */
void process_iod_events(mspool *nsp, msiod *nsi, int ev);
void process_event(mspool *nsp, gh_list *evlist, msevent *nse, int ev);
#if HAVE_PCAP
#ifndef PCAP_CAN_DO_SELECT
int pcap_read_on_nonselect(mspool *nsp);
#endif
#endif
/* defined in nsock_event.c */
void update_first_events(msevent *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(mspool *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(mspool *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(mspool *nsp, msiod *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(mspool *nsp, msiod *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(mspool *nsp, msiod *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(mspool *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 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 ... */
if (GH_LIST_COUNT(&nsp->active_iods) > einfo->evlen) {
einfo->evlen = GH_LIST_COUNT(&nsp->active_iods) * 2;
einfo->events = (struct epoll_event *)safe_realloc(einfo->events, einfo->evlen * sizeof(struct epoll_event));
}
do {
nsock_log_debug_all(nsp, "wait for events");
if (nsp->next_ev.tv_sec == 0)
event_msecs = -1; /* None of the events specified a timeout */
else
event_msecs = MAX(0, TIMEVAL_MSEC_SUBTRACT(nsp->next_ev, 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
{
if (einfo->evlen)
results_left = epoll_wait(einfo->epfd, einfo->events, einfo->evlen, combined_msecs);
else
results_left = 0;
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(mspool *nsp, int evcount) {
int n, initial_iod_count;
struct epoll_engine_info *einfo = (struct epoll_engine_info *)nsp->engine_data;
gh_list_elem *current, *next, *last, *timer_last, *last_active = NULL;
msevent *nse;
msiod *nsi;
/* Clear it -- We will find the next event as we go through the list */
nsp->next_ev.tv_sec = 0;
last = GH_LIST_LAST_ELEM(&nsp->active_iods);
timer_last = GH_LIST_LAST_ELEM(&nsp->timer_events);
initial_iod_count = GH_LIST_COUNT(&nsp->active_iods);
for (n = 0; n < evcount; n++) {
nsi = (msiod *)einfo->events[n].data.ptr;
assert(nsi);
if (nsi->entry_in_nsp_active_iods == last)
last = GH_LIST_ELEM_PREV(nsi->entry_in_nsp_active_iods);
/* 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_move_front(&nsp->active_iods, nsi->entry_in_nsp_active_iods);
if (last_active == NULL)
last_active = nsi->entry_in_nsp_active_iods;
} else {
gh_list_remove_elem(&nsp->active_iods, nsi->entry_in_nsp_active_iods);
gh_list_prepend(&nsp->free_iods, nsi);
}
}
if (evcount < initial_iod_count) {
/* some IODs had no active events and need to be processed */
if (!last_active)
/* either no IOD had events or all IODs were deleted after event processing */
current = GH_LIST_FIRST_ELEM(&nsp->active_iods);
else
/* IODs that had active events were pushed to the beginning of the list, start after them */
current = GH_LIST_ELEM_NEXT(last_active);
} else {
/* all the IODs had events and were therefore processed */
current = NULL;
}
/* cull timeouts amongst the non active IODs */
while (current != NULL && GH_LIST_ELEM_PREV(current) != last) {
nsi = (msiod *)GH_LIST_ELEM_DATA(current);
if (nsi->state != NSIOD_STATE_DELETED && nsi->events_pending)
process_iod_events(nsp, nsi, EV_NONE);
next = GH_LIST_ELEM_NEXT(current);
if (nsi->state == NSIOD_STATE_DELETED) {
gh_list_remove_elem(&nsp->active_iods, current);
gh_list_prepend(&nsp->free_iods, nsi);
}
current = next;
}
/* iterate through timers */
for (current = GH_LIST_FIRST_ELEM(&nsp->timer_events);
current != NULL && GH_LIST_ELEM_PREV(current) != timer_last; current = next) {
nse = (msevent *)GH_LIST_ELEM_DATA(current);
process_event(nsp, &nsp->timer_events, nse, EV_NONE);
next = GH_LIST_ELEM_NEXT(current);
if (nse->event_done)
gh_list_remove_elem(&nsp->timer_events, current);
}
}
#endif /* HAVE_EPOLL */
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