ViewVC Help
View File | Revision Log | Show Annotations | View Changeset | Root Listing
root/svn/ircd-hybrid/trunk/src/parse.c
Revision: 9415
Committed: Thu Jun 11 10:36:04 2020 UTC (5 years, 2 months ago) by michael
Content type: text/x-csrc
File size: 19091 byte(s)
Log Message:
- parse.c:parse(): move comment to where it really belongs to

File Contents

# Content
1 /*
2 * ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3 *
4 * Copyright (c) 1997-2020 ircd-hybrid development team
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19 * USA
20 */
21
22 /*! \file parse.c
23 * \brief The message parser.
24 * \version $Id$
25 */
26
27 #include "stdinc.h"
28 #include "client.h"
29 #include "parse.h"
30 #include "channel.h"
31 #include "hash.h"
32 #include "id.h"
33 #include "irc_string.h"
34 #include "ircd.h"
35 #include "numeric.h"
36 #include "log.h"
37 #include "send.h"
38 #include "conf.h"
39 #include "memory.h"
40 #include "user.h"
41 #include "server.h"
42 #include "packet.h"
43
44
45 /*
46 * (based on orabidoo's parser code)
47 *
48 * This has always just been a trie. Look at volume III of Knuth ACP
49 *
50 *
51 * ok, you start out with an array of pointers, each one corresponds
52 * to a letter at the current position in the command being examined.
53 *
54 * so roughly you have this for matching 'trie' or 'tie'
55 *
56 * 't' points -> [MessageTree *] 'r' -> [MessageTree *] -> 'i'
57 * -> [MessageTree *] -> [MessageTree *] -> 'e' and matches
58 *
59 * 'i' -> [MessageTree *] -> 'e' and matches
60 *
61 * BUGS (Limitations!)
62 *
63 * I designed this trie to parse ircd commands. Hence it currently
64 * casefolds. This is trivial to fix by increasing MAXPTRLEN.
65 * This trie also "folds" '{' etc. down. This means, the input to this
66 * trie must be alpha tokens only. This again, is a limitation that
67 * can be overcome by increasing MAXPTRLEN to include upper/lower case
68 * at the expense of more memory. At the extreme end, you could make
69 * MAXPTRLEN 128.
70 *
71 * This is also not a patricia trie. On short ircd tokens, this is
72 * not likely going to matter.
73 *
74 * Diane Bruce (Dianora), June 6 2003
75 */
76
77 /*
78 * Must be a power of 2, and larger than 26 [a-z]|[A-Z]. It's used to allocate
79 * the set of pointers at each node of the tree.
80 * There are MAXPTRLEN pointers at each node. Obviously, there have to be more
81 * pointers than ASCII letters. 32 is a nice number since there is then no need
82 * to shift 'A'/'a' to base 0 index, at the expense of a few never used
83 * pointers.
84 * For a small parser like this, this is a good compromise and does
85 * make it somewhat faster. - Dianora
86 */
87 enum { MAXPTRLEN = 32 };
88
89
90 static struct MessageTree
91 {
92 int links; /* Count of all pointers (including msg) at this node
93 * used as reference count for deletion of _this_ node.
94 */
95 struct Message *msg;
96 struct MessageTree *pointers[MAXPTRLEN];
97 } msg_tree;
98
99
100 /* remove_unknown()
101 *
102 * inputs -
103 * output -
104 * side effects -
105 */
106 static void
107 parse_remove_unknown(struct Client *client, const char *lsender, char *lbuffer)
108 {
109 /*
110 * Do kill if it came from a server because it means there is a ghost
111 * user on the other server which needs to be removed. -avalon
112 * Tell opers about this. -Taner
113 */
114 /*
115 * '[0-9]something' is an ID (KILL/SQUIT depending on its length)
116 * 'nodots' is a nickname (KILL)
117 * 'no.dot.at.start' is a server (SQUIT)
118 */
119 if ((IsDigit(*lsender) && strlen(lsender) <= IRC_MAXSID) || strchr(lsender, '.'))
120 {
121 sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
122 "Unknown prefix (%s) from %s, Squitting %s",
123 lbuffer, client_get_name(client, SHOW_IP), lsender);
124 sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
125 "Unknown prefix (%s) from %s, Squitting %s",
126 lbuffer, client_get_name(client, MASK_IP), lsender);
127 sendto_one(client, ":%s SQUIT %s :(Unknown prefix (%s) from %s)",
128 me.id, lsender, lbuffer, client->name);
129 }
130 else
131 sendto_one(client, ":%s KILL %s :%s (Unknown Client)",
132 me.id, lsender, me.name);
133 }
134
135 /*
136 *
137 * parc number of arguments ('sender' counted as one!)
138 * parv[0] pointer to 'sender' (may point to empty string) (not used)
139 * parv[1]..parv[parc-1]
140 * pointers to additional parameters, this is a NULL
141 * terminated list (parv[parc] == NULL).
142 *
143 * *WARNING*
144 * Numerics are mostly error reports. If there is something
145 * wrong with the message, just *DROP* it! Don't even think of
146 * sending back a neat error message -- big danger of creating
147 * a ping pong error message...
148 *
149 * Rewritten by Nemesi, Jan 1999, to support numeric nicks in parv[1]
150 *
151 * Called when we get a numeric message from a remote _server_ and we are
152 * supposed to forward it somewhere. Note that we always ignore numerics sent
153 * to 'me' and simply drop the message if we can't handle with this properly:
154 * the savvy approach is NEVER generate an error in response to an... error :)
155 */
156 static void
157 parse_handle_numeric(unsigned int numeric, struct Client *source, int parc, char *parv[])
158 {
159 /*
160 * Avoid trash, we need it to come from a server and have a target
161 */
162 if (parc < 2 || !IsServer(source))
163 return;
164
165 /*
166 * Remap low number numerics, not that I understand WHY.. --Nemesi
167 */
168 /*
169 * Numerics below 100 talk about the current 'connection', you're not
170 * connected to a remote server so it doesn't make sense to send them
171 * remotely - but the information they contain may be useful, so we
172 * remap them up. Weird, but true. -- Isomer
173 */
174 if (numeric < 100)
175 numeric += 100;
176
177 /*
178 * Who should receive this message ? Will we do something with it ?
179 * Note that we use findUser functions, so the target can't be neither
180 * a server, nor a channel (?) nor a list of targets (?) .. u2.10
181 * should never generate numeric replies to non-users anyway
182 * Ahem... it can be a channel actually, csc bots use it :\ --Nem
183 */
184 if (IsChanPrefix(*parv[1]))
185 {
186 struct Channel *channel = hash_find_channel(parv[1]);
187 if (channel == NULL)
188 return;
189
190 sendto_channel_butone(source, source, channel, 0, "%u %s %s",
191 numeric, channel->name, parv[2]);
192 }
193 else
194 {
195 struct Client *target = find_person(source, parv[1]);
196 if (target == NULL || target->from == source->from)
197 return;
198
199 /* Fake it for server hiding, if it's our client */
200 if ((ConfigServerHide.hide_servers || IsHidden(source)) && MyConnect(target) &&
201 !HasUMode(target, UMODE_OPER))
202 sendto_one_numeric(target, &me, numeric | SND_EXPLICIT, "%s", parv[2]);
203 else
204 sendto_one_numeric(target, source, numeric | SND_EXPLICIT, "%s", parv[2]);
205 }
206 }
207
208 /* handle_command()
209 *
210 * inputs - pointer to message block
211 * - pointer to client
212 * - pointer to client message is from
213 * - count of number of args
214 * - pointer to argv[] array
215 * output - -1 if error from server
216 * side effects -
217 */
218 static void
219 parse_handle_command(struct Message *message, struct Client *source,
220 unsigned int i, char *para[])
221 {
222 const struct MessageHandler *const handler = &message->handlers[source->from->handler];
223
224 if (IsServer(source->from))
225 ++message->rcount;
226 ++message->count;
227
228 if (handler->end_grace_period == true && MyClient(source))
229 flood_endgrace(source);
230
231 /* Check right amount of parameters is passed... --is */
232 if (handler->args_min &&
233 ((i < handler->args_min) ||
234 (handler->empty_last_arg != true && EmptyString(para[handler->args_min - 1]))))
235 sendto_one_numeric(source, &me, ERR_NEEDMOREPARAMS, message->cmd);
236 else
237 handler->handler(source, i, para);
238 }
239
240 /*
241 * parse a buffer.
242 *
243 * NOTE: parse() should not be called recusively by any other functions!
244 */
245 void
246 parse(struct Client *client, char *pbuffer, char *bufend)
247 {
248 struct Client *from = client;
249 struct Message *message = NULL;
250 char *para[MAXPARA + 2]; /* <command> + <parameters> + NULL */
251 char *ch = NULL;
252 char *s = NULL;
253 unsigned int numeric = 0;
254 unsigned int parc = 0;
255 unsigned int paramcount;
256
257 assert(!IsDead(client));
258 assert(client->connection);
259 assert(client->connection->fd);
260 assert(client->connection->fd->flags.open);
261 assert((bufend - pbuffer) < IRCD_BUFSIZE);
262
263 for (ch = pbuffer; *ch == ' '; ++ch) /* Skip spaces */
264 ;
265
266 if (*ch == ':')
267 {
268 /*
269 * Copy the prefix to 'sender' assuming it terminates
270 * with SPACE (or NULL, which is an error, though).
271 */
272 const char *const sender = ++ch;
273
274 if ((s = strchr(ch, ' ')))
275 {
276 *s = '\0';
277 ch = ++s;
278 }
279
280 if (*sender && IsServer(client))
281 {
282 if ((from = hash_find_id(sender)) == NULL)
283 from = hash_find_client(sender);
284
285 /*
286 * Hmm! If the client corresponding to the prefix is not found--what is
287 * the correct action??? Now, I will ignore the message (old IRC just
288 * let it through as if the prefix just wasn't there...) --msa
289 */
290 if (from == NULL)
291 {
292 ++ServerStats.is_unpf;
293 parse_remove_unknown(client, sender, pbuffer);
294 return;
295 }
296
297 if (from->from != client)
298 {
299 ++ServerStats.is_wrdi;
300 sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
301 "Fake direction: dropped message from %s[%s] via %s",
302 from->name, from->from->name,
303 client_get_name(client, SHOW_IP));
304 sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
305 "Fake direction: dropped message from %s[%s] via %s",
306 from->name, from->from->name,
307 client_get_name(client, MASK_IP));
308 return;
309 }
310 }
311
312 while (*ch == ' ')
313 ++ch;
314 }
315
316 if (*ch == '\0')
317 {
318 ++ServerStats.is_empt;
319 return;
320 }
321
322 /*
323 * Extract the command code from the packet. Point s to the end
324 * of the command code and calculate the length using pointer
325 * arithmetic. Note: only need length for numerics and *all*
326 * numerics must have parameters and thus a space after the command
327 * code. -avalon
328 */
329
330 /* EOB is 3 characters long but is not a numeric */
331 if (*(ch + 3) == ' ' && /* Ok, let's see if it's a possible numeric */
332 IsDigit(*ch) && IsDigit(*(ch + 1)) && IsDigit(*(ch + 2)))
333 {
334 numeric = (*ch - '0') * 100 + (*(ch + 1) - '0') * 10 + (*(ch + 2) - '0');
335 paramcount = 2; /* Destination, and the rest of it */
336 ++ServerStats.is_num;
337 s = ch + 3; /* I know this is ' ' from above if */
338 *s++ = '\0'; /* Blow away the ' ', and point s to next part */
339 }
340 else
341 {
342 if ((s = strchr(ch, ' ')))
343 *s++ = '\0';
344
345 if ((message = find_command(ch)) == NULL)
346 {
347 /*
348 * Note: Give error message *only* to recognized
349 * persons. It's a nightmare situation to have
350 * two programs sending "Unknown command"'s or
351 * equivalent to each other at full blast....
352 * If it has got to person state, it at least
353 * seems to be well behaving. Perhaps this message
354 * should never be generated, though... --msa
355 * Hm, when is the buffer empty -- if a command
356 * code has been found ?? -Armin
357 */
358 if (*pbuffer)
359 if (IsClient(from))
360 sendto_one_numeric(from, &me, ERR_UNKNOWNCOMMAND, ch);
361
362 ++ServerStats.is_unco;
363 return;
364 }
365
366 assert(message->cmd);
367
368 paramcount = message->handlers[from->from->handler].args_max;
369
370 size_t length = bufend - ((s) ? s : ch);
371 message->bytes += length;
372 }
373
374 memset(para, 0, sizeof(para));
375 para[parc] = ch;
376
377 if (message && message->extra)
378 {
379 /*
380 * XXX: This will have to go away after the command handler rewrite
381 */
382 para[++parc] = message->extra;
383 }
384
385 /*
386 * Must the following loop really be so devious? On surface it
387 * splits the message to parameters from blank spaces. But, if
388 * paramcount has been reached, the rest of the message goes into
389 * this last parameter (about same effect as ":" has...) --msa
390 */
391
392 /* Note initially true: s == NULL || *(s - 1) == '\0' !! */
393 if (s)
394 {
395 if (paramcount == 0 || paramcount > MAXPARA)
396 paramcount = MAXPARA;
397
398 while (true)
399 {
400 while (*s == ' ')
401 *s++ = '\0';
402
403 if (*s == '\0')
404 break;
405
406 if (*s == ':')
407 {
408 /* The rest is single parameter--can include blanks also. */
409 para[++parc] = s + (numeric == 0); /* Keep the colon if it's a numeric */
410 break;
411 }
412
413 para[++parc] = s;
414
415 if (parc >= paramcount)
416 break;
417
418 while (*s && *s != ' ')
419 ++s;
420 }
421 }
422
423 para[++parc] = NULL;
424
425 if (message)
426 parse_handle_command(message, from, parc, para);
427 else
428 parse_handle_numeric(numeric, from, parc, para);
429 }
430
431 /* add_msg_element()
432 *
433 * inputs - pointer to MessageTree
434 * - pointer to Message to add for given command
435 * - pointer to current portion of command being added
436 * output - NONE
437 * side effects - recursively build the Message Tree ;-)
438 */
439 /*
440 * How this works.
441 *
442 * The code first checks to see if its reached the end of the command
443 * If so, that struct MessageTree has a msg pointer updated and the links
444 * count incremented, since a msg pointer is a reference.
445 * Then the code descends recursively, building the trie.
446 * If a pointer index inside the struct MessageTree is NULL a new
447 * child struct MessageTree has to be allocated.
448 * The links (reference count) is incremented as they are created
449 * in the parent.
450 */
451 static void
452 add_msg_element(struct MessageTree *mtree_p, struct Message *msg_p,
453 const char *cmd)
454 {
455 if (*cmd == '\0')
456 {
457 mtree_p->msg = msg_p;
458 mtree_p->links++; /* Have msg pointer, so up ref count */
459 }
460 else
461 {
462 /*
463 * *cmd & (MAXPTRLEN-1)
464 * convert the char pointed to at *cmd from ASCII to an integer
465 * between 0 and MAXPTRLEN.
466 * Thus 'A' -> 0x1 'B' -> 0x2 'c' -> 0x3 etc.
467 */
468 struct MessageTree *ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)];
469 if (ntree_p == NULL)
470 {
471 ntree_p = xcalloc(sizeof(*ntree_p));
472 mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = ntree_p;
473
474 mtree_p->links++; /* Have new pointer, so up ref count */
475 }
476
477 add_msg_element(ntree_p, msg_p, cmd + 1);
478 }
479 }
480
481 /* del_msg_element()
482 *
483 * inputs - Pointer to MessageTree to delete from
484 * - pointer to command name to delete
485 * output - NONE
486 * side effects - recursively deletes a token from the Message Tree ;-)
487 */
488 /*
489 * How this works.
490 *
491 * Well, first off, the code recursively descends into the trie
492 * until it finds the terminating letter of the command being removed.
493 * Once it has done that, it marks the msg pointer as NULL then
494 * reduces the reference count on that allocated struct MessageTree
495 * since a command counts as a reference.
496 *
497 * Then it pops up the recurse stack. As it comes back up the recurse
498 * The code checks to see if the child now has no pointers or msg
499 * i.e. the links count has gone to zero. If it's no longer used, the
500 * child struct MessageTree can be deleted. The parent reference
501 * to this child is then removed and the parents link count goes down.
502 * Thus, we continue to go back up removing all unused MessageTree(s)
503 */
504 static void
505 del_msg_element(struct MessageTree *mtree_p, const char *cmd)
506 {
507 /*
508 * In case this is called for a nonexistent command
509 * check that there is a msg pointer here, else links-- goes -ve
510 * -db
511 */
512 if (*cmd == '\0' && mtree_p->msg)
513 {
514 mtree_p->msg = NULL;
515 mtree_p->links--;
516 }
517 else
518 {
519 struct MessageTree *ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)];
520 if (ntree_p)
521 {
522 del_msg_element(ntree_p, cmd + 1);
523
524 if (ntree_p->links == 0)
525 {
526 mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = NULL;
527 mtree_p->links--;
528 xfree(ntree_p);
529 }
530 }
531 }
532 }
533
534 /* msg_tree_parse()
535 *
536 * inputs - Pointer to command to find
537 * - Pointer to MessageTree root
538 * output - Find given command returning Message * if found NULL if not
539 * side effects - none
540 */
541 static struct Message *
542 msg_tree_parse(const char *cmd)
543 {
544 struct MessageTree *mtree = &msg_tree;
545
546 assert(!EmptyString(cmd));
547
548 while (IsAlpha(*cmd) && (mtree = mtree->pointers[*cmd & (MAXPTRLEN - 1)]))
549 if (*++cmd == '\0')
550 return mtree->msg;
551
552 return NULL;
553 }
554
555 /* mod_add_cmd()
556 *
557 * inputs - pointer to struct Message
558 * output - none
559 * side effects - load this one command name
560 */
561 void
562 mod_add_cmd(struct Message *msg)
563 {
564 assert(msg);
565 assert(msg->cmd);
566
567 /* Command already added? */
568 if (msg_tree_parse(msg->cmd) == NULL)
569 add_msg_element(&msg_tree, msg, msg->cmd);
570 }
571
572 /* mod_del_cmd()
573 *
574 * inputs - pointer to struct Message
575 * output - none
576 * side effects - unload this one command name
577 */
578 void
579 mod_del_cmd(struct Message *msg)
580 {
581 assert(msg);
582 assert(msg->cmd);
583
584 if (msg_tree_parse(msg->cmd))
585 del_msg_element(&msg_tree, msg->cmd);
586 }
587
588 /* find_command()
589 *
590 * inputs - command name
591 * output - pointer to struct Message
592 * side effects - none
593 */
594 struct Message *
595 find_command(const char *cmd)
596 {
597 return msg_tree_parse(cmd);
598 }
599
600 static void
601 recurse_report_messages(struct Client *source, const struct MessageTree *mtree)
602 {
603 if (mtree->msg)
604 sendto_one_numeric(source, &me, RPL_STATSCOMMANDS,
605 mtree->msg->cmd,
606 mtree->msg->count,
607 mtree->msg->bytes,
608 mtree->msg->rcount,
609 mtree->msg->ecount);
610
611 for (unsigned int i = 0; i < MAXPTRLEN; ++i)
612 if (mtree->pointers[i])
613 recurse_report_messages(source, mtree->pointers[i]);
614 }
615
616 /* report_messages()
617 *
618 * inputs - pointer to client to report to
619 * output - NONE
620 * side effects - client is shown list of commands
621 */
622 void
623 report_messages(struct Client *source)
624 {
625 const struct MessageTree *const mtree = &msg_tree;
626
627 for (unsigned int i = 0; i < MAXPTRLEN; ++i)
628 if (mtree->pointers[i])
629 recurse_report_messages(source, mtree->pointers[i]);
630 }
631
632 /* m_not_oper()
633 * inputs -
634 * output -
635 * side effects - just returns a nastyogram to given user
636 */
637 void
638 m_not_oper(struct Client *source, int parc, char *parv[])
639 {
640 sendto_one_numeric(source, &me, ERR_NOPRIVILEGES);
641 }
642
643 void
644 m_unregistered(struct Client *source, int parc, char *parv[])
645 {
646 sendto_one_numeric(source, &me, ERR_NOTREGISTERED);
647 }
648
649 void
650 m_registered(struct Client *source, int parc, char *parv[])
651 {
652 sendto_one_numeric(source, &me, ERR_ALREADYREGISTRED);
653 }
654
655 void
656 m_ignore(struct Client *source, int parc, char *parv[])
657 {
658 return;
659 }

Properties

Name Value
svn:eol-style native
svn:keywords Id