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Diffstat (limited to 'external/unbound/util/winsock_event.h')
| -rw-r--r-- | external/unbound/util/winsock_event.h | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/external/unbound/util/winsock_event.h b/external/unbound/util/winsock_event.h new file mode 100644 index 000000000..40892c14b --- /dev/null +++ b/external/unbound/util/winsock_event.h @@ -0,0 +1,264 @@ +/* + * util/winsock_event.h - unbound event handling for winsock on windows + * + * Copyright (c) 2008, NLnet Labs. All rights reserved. + * + * This software is open source. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of the NLNET LABS nor the names of its contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** + * \file + * + * This file contains interface functions with the WinSock2 API on Windows. + * It uses the winsock WSAWaitForMultipleEvents interface on a number of + * sockets. + * + * Note that windows can only wait for max 64 events at one time. + * + * Also, file descriptors cannot be waited for. + * + * Named pipes are not easily available (and are not usable in select() ). + * For interprocess communication, it is possible to wait for a hEvent to + * be signaled by another thread. + * + * When a socket becomes readable, then it will not be flagged as + * readable again until you have gotten WOULDBLOCK from a recv routine. + * That means the event handler must store the readability (edge notify) + * and process the incoming data until it blocks. + * The function performing recv then has to inform the event handler that + * the socket has blocked, and the event handler can mark it as such. + * Thus, this file transforms the edge notify from windows to a level notify + * that is compatible with UNIX. + * The WSAEventSelect page says that it does do level notify, as long + * as you call a recv/write/accept at least once when it is signalled. + * This last bit is not true, even though documented in server2008 api docs + * from microsoft, it does not happen at all. Instead you have to test for + * WSAEWOULDBLOCK on a tcp stream, and only then retest the socket. + * And before that remember the previous result as still valid. + * + * To stay 'fair', instead of emptying a socket completely, the event handler + * can test the other (marked as blocking) sockets for new events. + * + * Additionally, TCP accept sockets get special event support. + * + * Socket numbers are not starting small, they can be any number (say 33060). + * Therefore, bitmaps are not used, but arrays. + * + * on winsock, you must use recv() and send() for TCP reads and writes, + * not read() and write(), those work only on files. + * + * Also fseek and fseeko do not work if a FILE is not fopen-ed in binary mode. + * + * When under a high load windows gives out lots of errors, from recvfrom + * on udp sockets for example (WSAECONNRESET). Even though the udp socket + * has no connection per se. + */ + +#ifndef UTIL_WINSOCK_EVENT_H +#define UTIL_WINSOCK_EVENT_H + +#ifdef USE_WINSOCK + +#ifndef HAVE_EVENT_BASE_FREE +#define HAVE_EVENT_BASE_FREE +#endif + +/** event timeout */ +#define EV_TIMEOUT 0x01 +/** event fd readable */ +#define EV_READ 0x02 +/** event fd writable */ +#define EV_WRITE 0x04 +/** event signal */ +#define EV_SIGNAL 0x08 +/** event must persist */ +#define EV_PERSIST 0x10 + +/* needs our redblack tree */ +#include "rbtree.h" + +/** max number of signals to support */ +#define MAX_SIG 32 + +/** The number of items that the winsock event handler can service. + * Windows cannot handle more anyway */ +#define WSK_MAX_ITEMS 64 + +/** + * event base for winsock event handler + */ +struct event_base +{ + /** sorted by timeout (absolute), ptr */ + rbtree_t* times; + /** array (first part in use) of handles to work on */ + struct event** items; + /** number of items in use in array */ + int max; + /** capacity of array, size of array in items */ + int cap; + /** array of 0 - maxsig of ptr to event for it */ + struct event** signals; + /** if we need to exit */ + int need_to_exit; + /** where to store time in seconds */ + time_t* time_secs; + /** where to store time in microseconds */ + struct timeval* time_tv; + /** + * TCP streams have sticky events to them, these are not + * reported by the windows event system anymore, we have to + * keep reporting those events as present until wouldblock() is + * signalled by the handler back to use. + */ + int tcp_stickies; + /** + * should next cycle process reinvigorated stickies, + * these are stickies that have been stored, but due to a new + * event_add a sudden interest in the event has incepted. + */ + int tcp_reinvigorated; + /** The list of events that is currently being processed. */ + WSAEVENT waitfor[WSK_MAX_ITEMS]; +}; + +/** + * Event structure. Has some of the event elements. + */ +struct event { + /** node in timeout rbtree */ + rbnode_t node; + /** is event already added */ + int added; + + /** event base it belongs to */ + struct event_base *ev_base; + /** fd to poll or -1 for timeouts. signal number for sigs. */ + int ev_fd; + /** what events this event is interested in, see EV_.. above. */ + short ev_events; + /** timeout value */ + struct timeval ev_timeout; + + /** callback to call: fd, eventbits, userarg */ + void (*ev_callback)(int, short, void *); + /** callback user arg */ + void *ev_arg; + + /* ----- nonpublic part, for winsock_event only ----- */ + /** index of this event in the items array (if added) */ + int idx; + /** the event handle to wait for new events to become ready */ + WSAEVENT hEvent; + /** true if this filedes is a TCP socket and needs special attention */ + int is_tcp; + /** remembered EV_ values */ + short old_events; + /** should remembered EV_ values be used for TCP streams. + * Reset after WOULDBLOCK is signaled using the function. */ + int stick_events; + + /** true if this event is a signaling WSAEvent by the user. + * User created and user closed WSAEvent. Only signaled/unsigneled, + * no read/write/distinctions needed. */ + int is_signal; + /** used during callbacks to see which events were just checked */ + int just_checked; +}; + +/** create event base */ +void *event_init(time_t* time_secs, struct timeval* time_tv); +/** get version */ +const char *event_get_version(void); +/** get polling method (select,epoll) */ +const char *event_get_method(void); +/** run select in a loop */ +int event_base_dispatch(struct event_base *); +/** exit that loop */ +int event_base_loopexit(struct event_base *, struct timeval *); +/** free event base. Free events yourself */ +void event_base_free(struct event_base *); +/** set content of event */ +void event_set(struct event *, int, short, void (*)(int, short, void *), void *); + +/** add event to a base. You *must* call this for every event. */ +int event_base_set(struct event_base *, struct event *); +/** add event to make it active. You may not change it with event_set anymore */ +int event_add(struct event *, struct timeval *); +/** remove event. You may change it again */ +int event_del(struct event *); + +#define evtimer_add(ev, tv) event_add(ev, tv) +#define evtimer_del(ev) event_del(ev) + +/* uses different implementation. Cannot mix fd/timeouts and signals inside + * the same struct event. create several event structs for that. */ +/** install signal handler */ +int signal_add(struct event *, struct timeval *); +/** set signal event contents */ +#define signal_set(ev, x, cb, arg) \ + event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg) +/** remove signal handler */ +int signal_del(struct event *); + +/** compare events in tree, based on timevalue, ptr for uniqueness */ +int mini_ev_cmp(const void* a, const void* b); + +/** + * Routine for windows only, where the handling layer can signal that + * a TCP stream encountered WSAEWOULDBLOCK for a stream and thus needs + * retesting the event. + * Pass if EV_READ or EV_WRITE gave wouldblock. + */ +void winsock_tcp_wouldblock(struct event* ev, int eventbit); + +/** + * Routine for windows only. where you pass a signal WSAEvent that + * you wait for. When the event is signaled, the callback gets called. + * The callback has to WSAResetEvent to disable the signal. + * @param base: the event base. + * @param ev: the event structure for data storage + * can be passed uninitialised. + * @param wsaevent: the WSAEvent that gets signaled. + * @param cb: callback routine. + * @param arg: user argument to callback routine. + * @return false on error. + */ +int winsock_register_wsaevent(struct event_base* base, struct event* ev, + WSAEVENT wsaevent, void (*cb)(int, short, void*), void* arg); + +/** + * Unregister a wsaevent. User has to close the WSAEVENT itself. + * @param ev: event data storage. + */ +void winsock_unregister_wsaevent(struct event* ev); + +#endif /* USE_WINSOCK */ +#endif /* UTIL_WINSOCK_EVENT_H */ |