/*
- event.c -- event queue
- Copyright (C) 2002-2003 Guus Sliepen <guus@sliepen.eu.org>,
- 2002-2003 Ivo Timmermans <ivo@o2w.nl>
+ event.c -- I/O, timeout and signal event handling
+ Copyright (C) 2012-2018 Guus Sliepen <guus@tinc-vpn.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
- $Id: event.c,v 1.1.4.9 2003/07/17 15:06:26 guus Exp $
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "system.h"
-#include "avl_tree.h"
+#include "dropin.h"
#include "event.h"
+#include "net.h"
#include "utils.h"
#include "xalloc.h"
-avl_tree_t *event_tree;
-extern time_t now;
+struct timeval now;
+
+#ifndef HAVE_MINGW
+static fd_set readfds;
+static fd_set writefds;
+#else
+static const long READ_EVENTS = FD_READ | FD_ACCEPT | FD_CLOSE;
+static const long WRITE_EVENTS = FD_WRITE | FD_CONNECT;
+static DWORD event_count = 0;
+#endif
+static bool running;
+
+static int io_compare(const io_t *a, const io_t *b) {
+#ifndef HAVE_MINGW
+ return a->fd - b->fd;
+#else
+
+ if(a->event < b->event) {
+ return -1;
+ }
+
+ if(a->event > b->event) {
+ return 1;
+ }
+
+ return 0;
+#endif
+}
+
+static int timeout_compare(const timeout_t *a, const timeout_t *b) {
+ struct timeval diff;
+ timersub(&a->tv, &b->tv, &diff);
+
+ if(diff.tv_sec < 0) {
+ return -1;
+ }
+
+ if(diff.tv_sec > 0) {
+ return 1;
+ }
-int id;
+ if(diff.tv_usec < 0) {
+ return -1;
+ }
-static int event_compare(event_t *a, event_t *b)
-{
- if(a->time > b->time)
+ if(diff.tv_usec > 0) {
return 1;
+ }
- if(a->time < b->time)
+ if(a < b) {
return -1;
+ }
+
+ if(a > b) {
+ return 1;
+ }
+
+ return 0;
+}
+
+static splay_tree_t io_tree = {.compare = (splay_compare_t)io_compare};
+static splay_tree_t timeout_tree = {.compare = (splay_compare_t)timeout_compare};
+
+void io_add(io_t *io, io_cb_t cb, void *data, int fd, int flags) {
+ if(io->cb) {
+ return;
+ }
+
+ io->fd = fd;
+#ifdef HAVE_MINGW
+
+ if(io->fd != -1) {
+ io->event = WSACreateEvent();
+
+ if(io->event == WSA_INVALID_EVENT) {
+ abort();
+ }
+ }
+
+ event_count++;
+#endif
+ io->cb = cb;
+ io->data = data;
+ io->node.data = io;
- return a->id - b->id;
+ io_set(io, flags);
+
+ if(!splay_insert_node(&io_tree, &io->node)) {
+ abort();
+ }
}
-void init_events(void)
-{
- cp();
+#ifdef HAVE_MINGW
+void io_add_event(io_t *io, io_cb_t cb, void *data, WSAEVENT event) {
+ io->event = event;
+ io_add(io, cb, data, -1, 0);
+}
+#endif
+
+void io_set(io_t *io, int flags) {
+ if(flags == io->flags) {
+ return;
+ }
+
+ io->flags = flags;
+
+ if(io->fd == -1) {
+ return;
+ }
+
+#ifndef HAVE_MINGW
+
+ if(flags & IO_READ) {
+ FD_SET(io->fd, &readfds);
+ } else {
+ FD_CLR(io->fd, &readfds);
+ }
+
+ if(flags & IO_WRITE) {
+ FD_SET(io->fd, &writefds);
+ } else {
+ FD_CLR(io->fd, &writefds);
+ }
+
+#else
+ long events = 0;
+
+ if(flags & IO_WRITE) {
+ events |= WRITE_EVENTS;
+ }
+
+ if(flags & IO_READ) {
+ events |= READ_EVENTS;
+ }
+
+ if(WSAEventSelect(io->fd, io->event, events) != 0) {
+ abort();
+ }
- event_tree = avl_alloc_tree((avl_compare_t) event_compare, NULL);
+#endif
}
-void exit_events(void)
-{
- cp();
+void io_del(io_t *io) {
+ if(!io->cb) {
+ return;
+ }
- avl_delete_tree(event_tree);
+ io_set(io, 0);
+#ifdef HAVE_MINGW
+
+ if(io->fd != -1 && WSACloseEvent(io->event) == FALSE) {
+ abort();
+ }
+
+ event_count--;
+#endif
+
+ splay_unlink_node(&io_tree, &io->node);
+ io->cb = NULL;
}
-event_t *new_event(void)
-{
- cp();
+void timeout_add(timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
+ timeout->cb = cb;
+ timeout->data = data;
+ timeout->node.data = timeout;
- return (event_t *) xmalloc_and_zero(sizeof(event_t));
+ timeout_set(timeout, tv);
}
-void free_event(event_t *event)
-{
- cp();
+void timeout_set(timeout_t *timeout, struct timeval *tv) {
+ if(timerisset(&timeout->tv)) {
+ splay_unlink_node(&timeout_tree, &timeout->node);
+ }
+
+ if(!now.tv_sec) {
+ gettimeofday(&now, NULL);
+ }
+
+ timeradd(&now, tv, &timeout->tv);
- free(event);
+ if(!splay_insert_node(&timeout_tree, &timeout->node)) {
+ abort();
+ }
}
-void event_add(event_t *event)
-{
- cp();
+void timeout_del(timeout_t *timeout) {
+ if(!timeout->cb) {
+ return;
+ }
- event->id = ++id;
- avl_insert(event_tree, event);
+ splay_unlink_node(&timeout_tree, &timeout->node);
+ timeout->cb = 0;
+ timeout->tv = (struct timeval) {
+ 0, 0
+ };
}
-void event_del(event_t *event)
-{
- cp();
+#ifndef HAVE_MINGW
+static int signal_compare(const signal_t *a, const signal_t *b) {
+ return a->signum - b->signum;
+}
- avl_delete(event_tree, event);
+static io_t signalio;
+static int pipefd[2] = {-1, -1};
+static splay_tree_t signal_tree = {.compare = (splay_compare_t)signal_compare};
+
+static void signal_handler(int signum) {
+ unsigned char num = signum;
+ write(pipefd[1], &num, 1);
}
-event_t *get_expired_event(void)
-{
- event_t *event;
+static void signalio_handler(void *data, int flags) {
+ (void)data;
+ (void)flags;
+ unsigned char signum;
- cp();
+ if(read(pipefd[0], &signum, 1) != 1) {
+ return;
+ }
- if(event_tree->head) {
- event = (event_t *) event_tree->head->data;
+ signal_t *sig = splay_search(&signal_tree, &((signal_t) {
+ .signum = signum
+ }));
- if(event->time < now) {
- avl_delete(event_tree, event);
- return event;
+ if(sig) {
+ sig->cb(sig->data);
+ }
+}
+
+static void pipe_init(void) {
+ if(!pipe(pipefd)) {
+ io_add(&signalio, signalio_handler, NULL, pipefd[0], IO_READ);
+ }
+}
+
+void signal_add(signal_t *sig, signal_cb_t cb, void *data, int signum) {
+ if(sig->cb) {
+ return;
+ }
+
+ sig->cb = cb;
+ sig->data = data;
+ sig->signum = signum;
+ sig->node.data = sig;
+
+ if(pipefd[0] == -1) {
+ pipe_init();
+ }
+
+ signal(sig->signum, signal_handler);
+
+ if(!splay_insert_node(&signal_tree, &sig->node)) {
+ abort();
+ }
+}
+
+void signal_del(signal_t *sig) {
+ if(!sig->cb) {
+ return;
+ }
+
+ signal(sig->signum, SIG_DFL);
+
+ splay_unlink_node(&signal_tree, &sig->node);
+ sig->cb = NULL;
+}
+#endif
+
+static struct timeval *get_time_remaining(struct timeval *diff) {
+ gettimeofday(&now, NULL);
+ struct timeval *tv = NULL;
+
+ while(timeout_tree.head) {
+ timeout_t *timeout = timeout_tree.head->data;
+ timersub(&timeout->tv, &now, diff);
+
+ if(diff->tv_sec < 0) {
+ timeout->cb(timeout->data);
+
+ if(timercmp(&timeout->tv, &now, <)) {
+ timeout_del(timeout);
+ }
+ } else {
+ tv = diff;
+ break;
}
}
- return NULL;
+ return tv;
+}
+
+bool event_loop(void) {
+ running = true;
+
+#ifndef HAVE_MINGW
+ fd_set readable;
+ fd_set writable;
+
+ while(running) {
+ struct timeval diff;
+ struct timeval *tv = get_time_remaining(&diff);
+ memcpy(&readable, &readfds, sizeof(readable));
+ memcpy(&writable, &writefds, sizeof(writable));
+
+ int fds = 0;
+
+ if(io_tree.tail) {
+ io_t *last = io_tree.tail->data;
+ fds = last->fd + 1;
+ }
+
+ int n = select(fds, &readable, &writable, NULL, tv);
+
+ if(n < 0) {
+ if(sockwouldblock(sockerrno)) {
+ continue;
+ } else {
+ return false;
+ }
+ }
+
+ if(!n) {
+ continue;
+ }
+
+ unsigned int curgen = io_tree.generation;
+
+ for splay_each(io_t, io, &io_tree) {
+ if(FD_ISSET(io->fd, &writable)) {
+ io->cb(io->data, IO_WRITE);
+ } else if(FD_ISSET(io->fd, &readable)) {
+ io->cb(io->data, IO_READ);
+ } else {
+ continue;
+ }
+
+ /*
+ There are scenarios in which the callback will remove another io_t from the tree
+ (e.g. closing a double connection). Since splay_each does not support that, we
+ need to exit the loop if that happens. That's okay, since any remaining events will
+ get picked up by the next select() call.
+ */
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+ }
+
+#else
+
+ while(running) {
+ struct timeval diff;
+ struct timeval *tv = get_time_remaining(&diff);
+ DWORD timeout_ms = tv ? (DWORD)(tv->tv_sec * 1000 + tv->tv_usec / 1000 + 1) : WSA_INFINITE;
+
+ if(!event_count) {
+ Sleep(timeout_ms);
+ continue;
+ }
+
+ /*
+ For some reason, Microsoft decided to make the FD_WRITE event edge-triggered instead of level-triggered,
+ which is the opposite of what select() does. In practice, that means that if a FD_WRITE event triggers,
+ it will never trigger again until a send() returns EWOULDBLOCK. Since the semantics of this event loop
+ is that write events are level-triggered (i.e. they continue firing until the socket is full), we need
+ to emulate these semantics by making sure we fire each IO_WRITE that is still writeable.
+
+ Note that technically FD_CLOSE has the same problem, but it's okay because user code does not rely on
+ this event being fired again if ignored.
+ */
+ unsigned int curgen = io_tree.generation;
+
+ for splay_each(io_t, io, &io_tree) {
+ if(io->flags & IO_WRITE && send(io->fd, NULL, 0, 0) == 0) {
+ io->cb(io->data, IO_WRITE);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+ }
+
+ if(event_count > WSA_MAXIMUM_WAIT_EVENTS) {
+ WSASetLastError(WSA_INVALID_PARAMETER);
+ return(false);
+ }
+
+ WSAEVENT events[WSA_MAXIMUM_WAIT_EVENTS];
+ io_t *io_map[WSA_MAXIMUM_WAIT_EVENTS];
+ DWORD event_index = 0;
+
+ for splay_each(io_t, io, &io_tree) {
+ events[event_index] = io->event;
+ io_map[event_index] = io;
+ event_index++;
+ }
+
+ /*
+ * If the generation number changes due to event addition
+ * or removal by a callback we restart the loop.
+ */
+ curgen = io_tree.generation;
+
+ for(DWORD event_offset = 0; event_offset < event_count;) {
+ DWORD result = WSAWaitForMultipleEvents(event_count - event_offset, &events[event_offset], FALSE, timeout_ms, FALSE);
+
+ if(result == WSA_WAIT_TIMEOUT) {
+ break;
+ }
+
+ if(result >= event_count - event_offset) {
+ return(false);
+ }
+
+ /* Look up io in the map by index. */
+ event_index = result - event_offset;
+ io_t *io = io_map[event_index];
+
+ if(io->fd == -1) {
+ io->cb(io->data, 0);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ } else {
+ WSANETWORKEVENTS network_events;
+
+ if(WSAEnumNetworkEvents(io->fd, io->event, &network_events) != 0) {
+ return(false);
+ }
+
+ if(network_events.lNetworkEvents & READ_EVENTS) {
+ io->cb(io->data, IO_READ);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+
+ /*
+ The fd might be available for write too. However, if we already fired the read callback, that
+ callback might have deleted the io (e.g. through terminate_connection()), so we can't fire the
+ write callback here. Instead, we loop back and let the writable io loop above handle it.
+ */
+ }
+
+ /* Continue checking the rest of the events. */
+ event_offset = event_index + 1;
+
+ /* Just poll the next time through. */
+ timeout_ms = 0;
+ }
+ }
+
+#endif
+
+ return true;
+}
+
+void event_exit(void) {
+ running = false;
}
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