X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fwindows%2Fevent.c;fp=src%2Fwindows%2Fevent.c;h=a4688d0e573915a6ac19250d134f4a03de585366;hb=021293e0d03de8d29b22104a8f9bef625b135640;hp=0000000000000000000000000000000000000000;hpb=d3849fcb278d1df005c507f7e18a8397574f7f47;p=tinc diff --git a/src/windows/event.c b/src/windows/event.c new file mode 100644 index 00000000..a4688d0e --- /dev/null +++ b/src/windows/event.c @@ -0,0 +1,223 @@ +/* + event.c -- event support for Windows + Copyright (C) 2012-2022 Guus Sliepen + + 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 + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + 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 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., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#include "../system.h" + +#include + +#include "../event.h" +#include "../utils.h" +#include "../net.h" + +static bool running = false; +static DWORD event_count = 0; + +static const long READ_EVENTS = FD_READ | FD_ACCEPT | FD_CLOSE; +static const long WRITE_EVENTS = FD_WRITE | FD_CONNECT; + +void io_add(io_t *io, io_cb_t cb, void *data, int fd, int flags) { + if(io->cb) { + return; + } + + io->fd = fd; + + if(io->fd != -1) { + io->event = WSACreateEvent(); + + if(io->event == WSA_INVALID_EVENT) { + abort(); + } + } + + event_count++; + + io->cb = cb; + io->data = data; + io->node.data = io; + + io_set(io, flags); + + if(!splay_insert_node(&io_tree, &io->node)) { + abort(); + } +} + +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); +} + +void io_set(io_t *io, int flags) { + if(flags == io->flags) { + return; + } + + io->flags = flags; + + if(io->fd == -1) { + return; + } + + 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(); + } +} + +void io_del(io_t *io) { + if(!io->cb) { + return; + } + + io_set(io, 0); + + if(io->fd != -1 && WSACloseEvent(io->event) == FALSE) { + abort(); + } + + event_count--; + splay_unlink_node(&io_tree, &io->node); + io->cb = NULL; +} + +bool event_loop(void) { + running = true; + + assert(WSA_WAIT_EVENT_0 == 0); + + while(running) { + struct timeval diff; + struct timeval *tv = timeout_execute(&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; + } + } + + return true; +} + +void event_exit(void) { + running = false; +}