1 /* 2 * util/winsock_event.h - unbound event handling for winsock on windows 3 * 4 * Copyright (c) 2008, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains interface functions with the WinSock2 API on Windows. 40 * It uses the winsock WSAWaitForMultipleEvents interface on a number of 41 * sockets. 42 * 43 * Note that windows can only wait for max 64 events at one time. 44 * 45 * Also, file descriptors cannot be waited for. 46 * 47 * Named pipes are not easily available (and are not usable in select() ). 48 * For interprocess communication, it is possible to wait for a hEvent to 49 * be signaled by another thread. 50 * 51 * When a socket becomes readable, then it will not be flagged as 52 * readable again until you have gotten WOULDBLOCK from a recv routine. 53 * That means the event handler must store the readability (edge notify) 54 * and process the incoming data until it blocks. 55 * The function performing recv then has to inform the event handler that 56 * the socket has blocked, and the event handler can mark it as such. 57 * Thus, this file transforms the edge notify from windows to a level notify 58 * that is compatible with UNIX. 59 * The WSAEventSelect page says that it does do level notify, as long 60 * as you call a recv/write/accept at least once when it is signalled. 61 * This last bit is not true, even though documented in server2008 api docs 62 * from microsoft, it does not happen at all. Instead you have to test for 63 * WSAEWOULDBLOCK on a tcp stream, and only then retest the socket. 64 * And before that remember the previous result as still valid. 65 * 66 * To stay 'fair', instead of emptying a socket completely, the event handler 67 * can test the other (marked as blocking) sockets for new events. 68 * 69 * Additionally, TCP accept sockets get special event support. 70 * 71 * Socket numbers are not starting small, they can be any number (say 33060). 72 * Therefore, bitmaps are not used, but arrays. 73 * 74 * on winsock, you must use recv() and send() for TCP reads and writes, 75 * not read() and write(), those work only on files. 76 * 77 * Also fseek and fseeko do not work if a FILE is not fopen-ed in binary mode. 78 * 79 * When under a high load windows gives out lots of errors, from recvfrom 80 * on udp sockets for example (WSAECONNRESET). Even though the udp socket 81 * has no connection per se. 82 */ 83 84 #ifndef UTIL_WINSOCK_EVENT_H 85 #define UTIL_WINSOCK_EVENT_H 86 87 #ifdef USE_WINSOCK 88 89 #ifndef HAVE_EVENT_BASE_FREE 90 #define HAVE_EVENT_BASE_FREE 91 #endif 92 93 /** event timeout */ 94 #define EV_TIMEOUT 0x01 95 /** event fd readable */ 96 #define EV_READ 0x02 97 /** event fd writable */ 98 #define EV_WRITE 0x04 99 /** event signal */ 100 #define EV_SIGNAL 0x08 101 /** event must persist */ 102 #define EV_PERSIST 0x10 103 104 /* needs our redblack tree */ 105 #include "rbtree.h" 106 107 /** max number of signals to support */ 108 #define MAX_SIG 32 109 110 /** The number of items that the winsock event handler can service. 111 * Windows cannot handle more anyway */ 112 #define WSK_MAX_ITEMS 64 113 114 /** 115 * event base for winsock event handler 116 */ 117 struct event_base 118 { 119 /** sorted by timeout (absolute), ptr */ 120 rbtree_t* times; 121 /** array (first part in use) of handles to work on */ 122 struct event** items; 123 /** number of items in use in array */ 124 int max; 125 /** capacity of array, size of array in items */ 126 int cap; 127 /** array of 0 - maxsig of ptr to event for it */ 128 struct event** signals; 129 /** if we need to exit */ 130 int need_to_exit; 131 /** where to store time in seconds */ 132 uint32_t* time_secs; 133 /** where to store time in microseconds */ 134 struct timeval* time_tv; 135 /** 136 * TCP streams have sticky events to them, these are not 137 * reported by the windows event system anymore, we have to 138 * keep reporting those events as present until wouldblock() is 139 * signalled by the handler back to use. 140 */ 141 int tcp_stickies; 142 /** 143 * should next cycle process reinvigorated stickies, 144 * these are stickies that have been stored, but due to a new 145 * event_add a sudden interest in the event has incepted. 146 */ 147 int tcp_reinvigorated; 148 /** The list of events that is currently being processed. */ 149 WSAEVENT waitfor[WSK_MAX_ITEMS]; 150 }; 151 152 /** 153 * Event structure. Has some of the event elements. 154 */ 155 struct event { 156 /** node in timeout rbtree */ 157 rbnode_t node; 158 /** is event already added */ 159 int added; 160 161 /** event base it belongs to */ 162 struct event_base *ev_base; 163 /** fd to poll or -1 for timeouts. signal number for sigs. */ 164 int ev_fd; 165 /** what events this event is interested in, see EV_.. above. */ 166 short ev_events; 167 /** timeout value */ 168 struct timeval ev_timeout; 169 170 /** callback to call: fd, eventbits, userarg */ 171 void (*ev_callback)(int, short, void *); 172 /** callback user arg */ 173 void *ev_arg; 174 175 /* ----- nonpublic part, for winsock_event only ----- */ 176 /** index of this event in the items array (if added) */ 177 int idx; 178 /** the event handle to wait for new events to become ready */ 179 WSAEVENT hEvent; 180 /** true if this filedes is a TCP socket and needs special attention */ 181 int is_tcp; 182 /** remembered EV_ values */ 183 short old_events; 184 /** should remembered EV_ values be used for TCP streams. 185 * Reset after WOULDBLOCK is signaled using the function. */ 186 int stick_events; 187 188 /** true if this event is a signaling WSAEvent by the user. 189 * User created and user closed WSAEvent. Only signaled/unsigneled, 190 * no read/write/distinctions needed. */ 191 int is_signal; 192 /** used during callbacks to see which events were just checked */ 193 int just_checked; 194 }; 195 196 /** create event base */ 197 void *event_init(uint32_t* time_secs, struct timeval* time_tv); 198 /** get version */ 199 const char *event_get_version(void); 200 /** get polling method (select,epoll) */ 201 const char *event_get_method(void); 202 /** run select in a loop */ 203 int event_base_dispatch(struct event_base *); 204 /** exit that loop */ 205 int event_base_loopexit(struct event_base *, struct timeval *); 206 /** free event base. Free events yourself */ 207 void event_base_free(struct event_base *); 208 /** set content of event */ 209 void event_set(struct event *, int, short, void (*)(int, short, void *), void *); 210 211 /** add event to a base. You *must* call this for every event. */ 212 int event_base_set(struct event_base *, struct event *); 213 /** add event to make it active. You may not change it with event_set anymore */ 214 int event_add(struct event *, struct timeval *); 215 /** remove event. You may change it again */ 216 int event_del(struct event *); 217 218 #define evtimer_add(ev, tv) event_add(ev, tv) 219 #define evtimer_del(ev) event_del(ev) 220 221 /* uses different implementation. Cannot mix fd/timeouts and signals inside 222 * the same struct event. create several event structs for that. */ 223 /** install signal handler */ 224 int signal_add(struct event *, struct timeval *); 225 /** set signal event contents */ 226 #define signal_set(ev, x, cb, arg) \ 227 event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg) 228 /** remove signal handler */ 229 int signal_del(struct event *); 230 231 /** compare events in tree, based on timevalue, ptr for uniqueness */ 232 int mini_ev_cmp(const void* a, const void* b); 233 234 /** 235 * Routine for windows only, where the handling layer can signal that 236 * a TCP stream encountered WSAEWOULDBLOCK for a stream and thus needs 237 * retesting the event. 238 * Pass if EV_READ or EV_WRITE gave wouldblock. 239 */ 240 void winsock_tcp_wouldblock(struct event* ev, int eventbit); 241 242 /** 243 * Routine for windows only. where you pass a signal WSAEvent that 244 * you wait for. When the event is signaled, the callback gets called. 245 * The callback has to WSAResetEvent to disable the signal. 246 * @param base: the event base. 247 * @param ev: the event structure for data storage 248 * can be passed uninitialised. 249 * @param wsaevent: the WSAEvent that gets signaled. 250 * @param cb: callback routine. 251 * @param arg: user argument to callback routine. 252 * @return false on error. 253 */ 254 int winsock_register_wsaevent(struct event_base* base, struct event* ev, 255 WSAEVENT wsaevent, void (*cb)(int, short, void*), void* arg); 256 257 /** 258 * Unregister a wsaevent. User has to close the WSAEVENT itself. 259 * @param ev: event data storage. 260 */ 261 void winsock_unregister_wsaevent(struct event* ev); 262 263 #endif /* USE_WINSOCK */ 264 #endif /* UTIL_WINSOCK_EVENT_H */ 265