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1 | /************************************************************************ | |
2 | * IRC - Internet Relay Chat, src/listener.c | |
3 | * Copyright (C) 1999 Thomas Helvey <tomh@inxpress.net> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 1, or (at your option) | |
8 | * any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
18 | */ | |
19 | /** @file | |
20 | * @brief Implementation for handling listening sockets. | |
21 | * @version $Id: listener.c,v 1.28.2.1 2006/03/14 03:45:52 entrope Exp $ | |
22 | */ | |
23 | #include "config.h" | |
24 | ||
25 | #include "listener.h" | |
26 | #include "client.h" | |
27 | #include "ircd.h" | |
28 | #include "ircd_alloc.h" | |
29 | #include "ircd_events.h" | |
30 | #include "ircd_features.h" | |
31 | #include "ircd_log.h" | |
32 | #include "ircd_osdep.h" | |
33 | #include "ircd_reply.h" | |
34 | #include "ircd_snprintf.h" | |
35 | #include "ircd_string.h" | |
36 | #include "match.h" | |
37 | #include "numeric.h" | |
38 | #include "s_bsd.h" | |
39 | #include "s_conf.h" | |
40 | #include "s_misc.h" | |
41 | #include "s_stats.h" | |
42 | #include "send.h" | |
43 | #include "sys.h" /* MAXCLIENTS */ | |
44 | ||
45 | /* #include <assert.h> -- Now using assert in ircd_log.h */ | |
46 | #include <stdio.h> | |
47 | #include <string.h> | |
48 | #include <errno.h> | |
49 | #include <stdlib.h> | |
50 | #include <unistd.h> | |
51 | #include <netdb.h> | |
52 | #include <sys/socket.h> | |
53 | ||
54 | /** List of listening sockets. */ | |
55 | struct Listener* ListenerPollList = 0; | |
56 | ||
57 | static void accept_connection(struct Event* ev); | |
58 | ||
59 | /** Allocate and initialize a new Listener structure for a particular | |
60 | * socket address. | |
61 | * @param[in] port Port number to listen on. | |
62 | * @param[in] addr Local address to listen on. | |
63 | * @return Newly allocated and initialized Listener. | |
64 | */ | |
65 | static struct Listener* make_listener(int port, const struct irc_in_addr *addr) | |
66 | { | |
67 | struct Listener* listener = | |
68 | (struct Listener*) MyMalloc(sizeof(struct Listener)); | |
69 | assert(0 != listener); | |
70 | ||
71 | memset(listener, 0, sizeof(struct Listener)); | |
72 | ||
73 | listener->fd = -1; | |
74 | listener->addr.port = port; | |
75 | memcpy(&listener->addr.addr, addr, sizeof(listener->addr.addr)); | |
76 | ||
77 | #ifdef NULL_POINTER_NOT_ZERO | |
78 | listener->next = NULL; | |
79 | listener->conf = NULL; | |
80 | #endif | |
81 | return listener; | |
82 | } | |
83 | ||
84 | /** Deallocate a Listener structure. | |
85 | * @param[in] listener Listener to be freed. | |
86 | */ | |
87 | static void free_listener(struct Listener* listener) | |
88 | { | |
89 | assert(0 != listener); | |
90 | MyFree(listener); | |
91 | } | |
92 | ||
93 | /** Maximum length for a port number. */ | |
94 | #define PORTNAMELEN 10 /* ":31337" */ | |
95 | ||
96 | /** Return displayable listener name and port. | |
97 | * @param[in] listener %Listener to format as a text string. | |
98 | * @return Pointer to a static buffer that contains "server.name:6667". | |
99 | */ | |
100 | const char* get_listener_name(const struct Listener* listener) | |
101 | { | |
102 | static char buf[HOSTLEN + PORTNAMELEN + 4]; | |
103 | assert(0 != listener); | |
104 | ircd_snprintf(0, buf, sizeof(buf), "%s:%u", cli_name(&me), listener->addr.port); | |
105 | return buf; | |
106 | } | |
107 | ||
108 | /** Count allocated listeners and the memory they use. | |
109 | * @param[out] count_out Receives number of allocated listeners. | |
110 | * @param[out] size_out Receives bytes used by listeners. | |
111 | */ | |
112 | void count_listener_memory(int* count_out, size_t* size_out) | |
113 | { | |
114 | struct Listener* l; | |
115 | int count = 0; | |
116 | assert(0 != count_out); | |
117 | assert(0 != size_out); | |
118 | for (l = ListenerPollList; l; l = l->next) | |
119 | ++count; | |
120 | *count_out = count; | |
121 | *size_out = count * sizeof(struct Listener); | |
122 | } | |
123 | ||
124 | /** Report listening ports to a client. | |
125 | * @param[in] sptr Client requesting statistics. | |
126 | * @param[in] sd Stats descriptor for request (ignored). | |
127 | * @param[in] param Extra parameter from user (port number to search for). | |
128 | */ | |
129 | void show_ports(struct Client* sptr, const struct StatDesc* sd, | |
130 | char* param) | |
131 | { | |
132 | struct Listener *listener = 0; | |
133 | char flags[8]; | |
134 | int show_hidden = IsOper(sptr); | |
135 | int count = (IsOper(sptr) || MyUser(sptr)) ? 100 : 8; | |
136 | int port = 0; | |
137 | ||
138 | assert(0 != sptr); | |
139 | ||
140 | if (param) | |
141 | port = atoi(param); | |
142 | ||
143 | for (listener = ListenerPollList; listener; listener = listener->next) { | |
144 | if (port && port != listener->addr.port) | |
145 | continue; | |
146 | flags[0] = (listener->server) ? 'S' : 'C'; | |
147 | if (listener->hidden) { | |
148 | if (!show_hidden) | |
149 | continue; | |
150 | flags[1] = 'H'; | |
151 | flags[2] = '\0'; | |
152 | } | |
153 | else | |
154 | flags[1] = '\0'; | |
155 | ||
156 | send_reply(sptr, RPL_STATSPLINE, listener->addr.port, listener->ref_count, | |
157 | flags, (listener->active) ? "active" : "disabled"); | |
158 | if (--count == 0) | |
159 | break; | |
160 | } | |
161 | } | |
162 | ||
163 | /* | |
164 | * inetport - create a listener socket in the AF_INET domain, | |
165 | * bind it to the port given in 'port' and listen to it | |
166 | * returns true (1) if successful false (0) on error. | |
167 | * | |
168 | * If the operating system has a define for SOMAXCONN, use it, otherwise | |
169 | * use HYBRID_SOMAXCONN -Dianora | |
170 | * NOTE: Do this in os_xxxx.c files | |
171 | */ | |
172 | #ifdef SOMAXCONN | |
173 | #define HYBRID_SOMAXCONN SOMAXCONN | |
174 | #else | |
175 | /** Maximum length of socket connection backlog. */ | |
176 | #define HYBRID_SOMAXCONN 64 | |
177 | #endif | |
178 | ||
179 | /** Open listening socket for \a listener. | |
180 | * @param[in,out] listener Listener to make a socket for. | |
181 | * @return Non-zero on success, zero on failure. | |
182 | */ | |
183 | static int inetport(struct Listener* listener) | |
184 | { | |
185 | int fd; | |
186 | ||
187 | /* | |
188 | * At first, open a new socket | |
189 | */ | |
190 | fd = os_socket(&listener->addr, SOCK_STREAM, get_listener_name(listener), 0); | |
191 | if (fd < 0) | |
192 | return 0; | |
193 | /* | |
194 | * Set the buffer sizes for the listener. Accepted connections | |
195 | * inherit the accepting sockets settings for SO_RCVBUF S_SNDBUF | |
196 | * The window size is set during the SYN ACK so setting it anywhere | |
197 | * else has no effect whatsoever on the connection. | |
198 | * NOTE: this must be set before listen is called | |
199 | */ | |
200 | if (!os_set_sockbufs(fd, | |
201 | (listener->server) ? feature_int(FEAT_SOCKSENDBUF) : CLIENT_TCP_WINDOW, | |
202 | (listener->server) ? feature_int(FEAT_SOCKRECVBUF) : CLIENT_TCP_WINDOW)) { | |
203 | report_error(SETBUFS_ERROR_MSG, get_listener_name(listener), errno); | |
204 | close(fd); | |
205 | return 0; | |
206 | } | |
207 | if (!os_set_listen(fd, HYBRID_SOMAXCONN)) { | |
208 | report_error(LISTEN_ERROR_MSG, get_listener_name(listener), errno); | |
209 | close(fd); | |
210 | return 0; | |
211 | } | |
212 | /* | |
213 | * Set the TOS bits - this is nonfatal if it doesn't stick. | |
214 | */ | |
215 | if (!os_set_tos(fd,feature_int((listener->server)?FEAT_TOS_SERVER : FEAT_TOS_CLIENT))) { | |
216 | report_error(TOS_ERROR_MSG, get_listener_name(listener), errno); | |
217 | } | |
218 | ||
219 | if (!socket_add(&listener->socket, accept_connection, (void*) listener, | |
220 | SS_LISTENING, 0, fd)) { | |
221 | /* Error should already have been reported to the logs */ | |
222 | close(fd); | |
223 | return 0; | |
224 | } | |
225 | ||
226 | listener->fd = fd; | |
227 | ||
228 | return 1; | |
229 | } | |
230 | ||
231 | /** Find the listener (if any) for a particular port and address. | |
232 | * @param[in] port Port number to search for. | |
233 | * @param[in] addr Local address to search for. | |
234 | * @return Listener that matches (or NULL if none match). | |
235 | */ | |
236 | static struct Listener* find_listener(int port, const struct irc_in_addr *addr) | |
237 | { | |
238 | struct Listener* listener; | |
239 | for (listener = ListenerPollList; listener; listener = listener->next) { | |
240 | if (port == listener->addr.port && !memcmp(addr, &listener->addr.addr, sizeof(*addr))) | |
241 | return listener; | |
242 | } | |
243 | return 0; | |
244 | } | |
245 | ||
246 | /** Make sure we have a listener for \a port on \a vhost_ip. | |
247 | * If one does not exist, create it. Then mark it as active and set | |
248 | * the peer mask, server, and hidden flags according to the other | |
249 | * arguments. | |
250 | * @param[in] port Port number to listen on. | |
251 | * @param[in] vhost_ip Local address to listen on. | |
252 | * @param[in] mask Address mask to accept connections from. | |
253 | * @param[in] is_server Non-zero if the port should only accept server connections. | |
254 | * @param[in] is_hidden Non-zero if the port should be hidden from /STATS P output. | |
255 | */ | |
256 | void add_listener(int port, const char* vhost_ip, const char* mask, | |
257 | int is_server, int is_hidden) | |
258 | { | |
259 | struct Listener* listener; | |
260 | struct irc_in_addr vaddr; | |
261 | ||
262 | /* | |
263 | * if no port in conf line, don't bother | |
264 | */ | |
265 | if (0 == port) | |
266 | return; | |
267 | ||
268 | memset(&vaddr, 0, sizeof(vaddr)); | |
269 | ||
270 | if (!EmptyString(vhost_ip) | |
271 | && strcmp(vhost_ip, "*") | |
272 | && !ircd_aton(&vaddr, vhost_ip)) | |
273 | return; | |
274 | ||
275 | listener = find_listener(port, &vaddr); | |
276 | if (!listener) | |
277 | listener = make_listener(port, &vaddr); | |
278 | listener->active = 1; | |
279 | listener->hidden = is_hidden; | |
280 | listener->server = is_server; | |
281 | if (mask) | |
282 | ipmask_parse(mask, &listener->mask, &listener->mask_bits); | |
283 | else | |
284 | listener->mask_bits = 0; | |
285 | ||
286 | if (listener->fd >= 0) { | |
287 | /* If the listener is already open, do not try to re-open. */ | |
288 | } | |
289 | else if (inetport(listener)) { | |
290 | listener->next = ListenerPollList; | |
291 | ListenerPollList = listener; | |
292 | } | |
293 | else | |
294 | free_listener(listener); | |
295 | } | |
296 | ||
297 | /** Mark all listeners as closing (inactive). | |
298 | * This is done so unused listeners are closed after a rehash. | |
299 | */ | |
300 | void mark_listeners_closing(void) | |
301 | { | |
302 | struct Listener* listener; | |
303 | for (listener = ListenerPollList; listener; listener = listener->next) | |
304 | listener->active = 0; | |
305 | } | |
306 | ||
307 | /** Close a single listener. | |
308 | * @param[in] listener Listener to close. | |
309 | */ | |
310 | void close_listener(struct Listener* listener) | |
311 | { | |
312 | assert(0 != listener); | |
313 | /* | |
314 | * remove from listener list | |
315 | */ | |
316 | if (listener == ListenerPollList) | |
317 | ListenerPollList = listener->next; | |
318 | else { | |
319 | struct Listener* prev = ListenerPollList; | |
320 | for ( ; prev; prev = prev->next) { | |
321 | if (listener == prev->next) { | |
322 | prev->next = listener->next; | |
323 | break; | |
324 | } | |
325 | } | |
326 | } | |
327 | if (-1 < listener->fd) | |
328 | close(listener->fd); | |
329 | socket_del(&listener->socket); | |
330 | } | |
331 | ||
332 | /** Close all inactive listeners. */ | |
333 | void close_listeners(void) | |
334 | { | |
335 | struct Listener* listener; | |
336 | struct Listener* listener_next = 0; | |
337 | /* | |
338 | * close all 'extra' listening ports we have | |
339 | */ | |
340 | for (listener = ListenerPollList; listener; listener = listener_next) { | |
341 | listener_next = listener->next; | |
342 | if (0 == listener->active && 0 == listener->ref_count) | |
343 | close_listener(listener); | |
344 | } | |
345 | } | |
346 | ||
347 | /** Dereference the listener previously associated with a client. | |
348 | * @param[in] listener Listener to dereference. | |
349 | */ | |
350 | void release_listener(struct Listener* listener) | |
351 | { | |
352 | assert(0 != listener); | |
353 | assert(0 < listener->ref_count); | |
354 | if (0 == --listener->ref_count && !listener->active) | |
355 | close_listener(listener); | |
356 | } | |
357 | ||
358 | /** Accept a connection on a listener. | |
359 | * @param[in] ev Socket callback structure. | |
360 | */ | |
361 | static void accept_connection(struct Event* ev) | |
362 | { | |
363 | struct Listener* listener; | |
364 | struct irc_sockaddr addr; | |
365 | int fd; | |
366 | ||
367 | assert(0 != ev_socket(ev)); | |
368 | assert(0 != s_data(ev_socket(ev))); | |
369 | ||
370 | listener = (struct Listener*) s_data(ev_socket(ev)); | |
371 | ||
372 | if (ev_type(ev) == ET_DESTROY) /* being destroyed */ | |
373 | free_listener(listener); | |
374 | else { | |
375 | assert(ev_type(ev) == ET_ACCEPT || ev_type(ev) == ET_ERROR); | |
376 | ||
377 | listener->last_accept = CurrentTime; | |
378 | /* | |
379 | * There may be many reasons for error return, but | |
380 | * in otherwise correctly working environment the | |
381 | * probable cause is running out of file descriptors | |
382 | * (EMFILE, ENFILE or others?). The man pages for | |
383 | * accept don't seem to list these as possible, | |
384 | * although it's obvious that it may happen here. | |
385 | * Thus no specific errors are tested at this | |
386 | * point, just assume that connections cannot | |
387 | * be accepted until some old is closed first. | |
388 | * | |
389 | * This piece of code implements multi-accept, based | |
390 | * on the idea that poll/select can only be efficient, | |
391 | * if we succeed in handling all available events, | |
392 | * i.e. accept all pending connections. | |
393 | * | |
394 | * http://www.hpl.hp.com/techreports/2000/HPL-2000-174.html | |
395 | */ | |
396 | while (1) | |
397 | { | |
398 | if ((fd = os_accept(listener->fd, &addr)) == -1) | |
399 | { | |
400 | if (errno == EAGAIN || | |
401 | #ifdef EWOULDBLOCK | |
402 | errno == EWOULDBLOCK) | |
403 | #endif | |
404 | return; | |
405 | /* Lotsa admins seem to have problems with not giving enough file | |
406 | * descriptors to their server so we'll add a generic warning mechanism | |
407 | * here. If it turns out too many messages are generated for | |
408 | * meaningless reasons we can filter them back. | |
409 | */ | |
410 | sendto_opmask_butone(0, SNO_TCPCOMMON, | |
411 | "Unable to accept connection: %m"); | |
412 | return; | |
413 | } | |
414 | /* | |
415 | * check for connection limit. If this fd exceeds the limit, | |
416 | * all further accept()ed connections will also exceed it. | |
417 | * Enable the server to clear out other connections before | |
418 | * continuing to accept() new connections. | |
419 | */ | |
420 | if (fd > MAXCLIENTS - 1) | |
421 | { | |
422 | ++ServerStats->is_ref; | |
423 | send(fd, "ERROR :All connections in use\r\n", 32, 0); | |
424 | close(fd); | |
425 | return; | |
426 | } | |
427 | /* | |
428 | * check to see if listener is shutting down. Continue | |
429 | * to accept(), because it makes sense to clear our the | |
430 | * socket's queue as fast as possible. | |
431 | */ | |
432 | if (!listener->active) | |
433 | { | |
434 | ++ServerStats->is_ref; | |
435 | send(fd, "ERROR :Use another port\r\n", 25, 0); | |
436 | close(fd); | |
437 | continue; | |
438 | } | |
439 | /* | |
440 | * check to see if connection is allowed for this address mask | |
441 | */ | |
442 | if (!ipmask_check(&addr.addr, &listener->mask, listener->mask_bits)) | |
443 | { | |
444 | ++ServerStats->is_ref; | |
445 | send(fd, "ERROR :Use another port\r\n", 25, 0); | |
446 | close(fd); | |
447 | continue; | |
448 | } | |
449 | ++ServerStats->is_ac; | |
450 | /* nextping = CurrentTime; */ | |
451 | add_connection(listener, fd); | |
452 | } | |
453 | } | |
454 | } |