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Comparing ircd-hybrid/branches/8.2.x/src/res.c (file contents):
Revision 4235 by michael, Tue Jul 15 17:32:14 2014 UTC vs.
Revision 4312 by michael, Thu Jul 31 17:02:26 2014 UTC

#	Line 25 | Line 25
25		*/
26
27		/*
28	<	* A rewrite of Darren Reeds original res.c As there is nothing
29	<	* left of Darrens original code, this is now licensed by the hybrid group.
28	>	* A rewrite of Darren Reed's original res.c As there is nothing
29	>	* left of Darren's original code, this is now licensed by the hybrid group.
30		* (Well, some of the function names are the same, and bits of the structs..)
31		* You can use it where it is useful, free even. Buy us a beer and stuff.
32		*
33		* The authors takes no responsibility for any damage or loss
34		* of property which results from the use of this software.
35		*
36	–	* $Id$
37	–	*
36		* July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
37		*     added callbacks and reference counting of returned hostents.
38		*     --Bleep (Thomas Helvey <tomh@inxpress.net>)
39		*
40		* This was all needlessly complicated for irc. Simplified. No more hostent
41	<	* All we really care about is the IP -> hostname mappings. Thats all.
41	>	* All we really care about is the IP -> hostname mappings. That's all.
42		*
43		* Apr 28, 2003 --cryogen and Dianora
44		*/
#	Line 69 | Line 67
67
68		static PF res_readreply;
69
70	<	#define MAXPACKET      1024  /* rfc sez 512 but we expand names so ... */
71	<	#define AR_TTL         600   /* TTL in seconds for dns cache entries */
70	>	#define MAXPACKET      1024  /**< rfc says 512 but we expand names so ... */
71	>	#define AR_TTL         600   /**< TTL in seconds for dns cache entries */
72
73	<	/* RFC 1104/1105 wasn't very helpful about what these fields
73	>	/*
74	>	* RFC 1104/1105 wasn't very helpful about what these fields
75		* should be named, so for now, we'll just name them this way.
76	<	* we probably should look at what named calls them or something.
76	>	* We probably should look at what named calls them or something.
77		*/
78		#define TYPE_SIZE         (size_t)2
79		#define CLASS_SIZE        (size_t)2
#	Line 84 | Line 83 | static PF res_readreply;
83
84		typedef enum
85		{
86	<	REQ_IDLE,  /* We're doing not much at all */
87	<	REQ_PTR,   /* Looking up a PTR */
88	<	REQ_A,     /* Looking up an A, possibly because AAAA failed */
86	>	REQ_IDLE,  /**< We're doing not much at all */
87	>	REQ_PTR,   /**< Looking up a PTR */
88	>	REQ_A,     /**< Looking up an A, possibly because AAAA failed */
89		#ifdef IPV6
90	<	REQ_AAAA,  /* Looking up an AAAA */
90	>	REQ_AAAA,  /**< Looking up an AAAA */
91		#endif
92	<	REQ_CNAME  /* We got a CNAME in response, we better get a real answer next */
92	>	REQ_CNAME  /**< We got a CNAME in response, we better get a real answer next */
93		} request_state;
94
95		struct reslist
96		{
97	<	dlink_node node;
98	<	int id;
99	<	int sent;                /* number of requests sent */
100	<	request_state state;     /* State the resolver machine is in */
101	<	time_t ttl;
102	<	char type;
103	<	char retries;            /* retry counter */
104	<	unsigned int sends;      /* number of sends (>1 means resent) */
105	<	char resend;             /* send flag. 0 == dont resend */
106	<	time_t sentat;
107	<	time_t timeout;
108	<	struct irc_ssaddr addr;
109	<	char *name;
110	<	dns_callback_fnc callback;
112	<	void *callback_ctx;
97	>	dlink_node node;            /**< Doubly linked list node. */
98	>	int id;                     /**< Request ID (from request header). */
99	>	int sent;                   /**< Number of requests sent */
100	>	request_state state;        /**< State the resolver machine is in */
101	>	char type;                  /**< Current request type. */
102	>	char retries;               /**< Retry counter */
103	>	unsigned int sends;         /**< Number of sends (>1 means resent). */
104	>	char resend;                /**< Send flag; 0 == don't resend. */
105	>	time_t sentat;              /**< Timestamp we last sent this request. */
106	>	time_t timeout;             /**< When this request times out. */
107	>	struct irc_ssaddr addr;     /**< Address for this request. */
108	>	char *name;                 /**< Hostname for this request. */
109	>	dns_callback_fnc callback;  /**< Callback function on completion. */
110	>	void *callback_ctx;         /**< Context pointer for callback. */
111		};
112
113		static fde_t ResolverFileDescriptor;
114		static dlink_list request_list;
115		static mp_pool_t *dns_pool;
116
119	–	static void rem_request(struct reslist *);
120	–	static struct reslist *make_request(dns_callback_fnc, void *);
121	–	static void do_query_name(dns_callback_fnc, void *,
122	–	const char *, struct reslist *, int);
123	–	static void do_query_number(dns_callback_fnc, void *,
124	–	const struct irc_ssaddr *,
125	–	struct reslist *);
126	–	static void query_name(const char *, int, int, struct reslist *);
127	–	static int send_res_msg(const char *, int, unsigned int);
128	–	static void resend_query(struct reslist *);
129	–	static int proc_answer(struct reslist *, HEADER *, char *, char *);
130	–	static struct reslist *find_id(int);
117
118	+	/*
119	+	* rem_request - remove a request from the list.
120	+	* This must also free any memory that has been allocated for
121	+	* temporary storage of DNS results.
122	+	*/
123	+	static void
124	+	rem_request(struct reslist *request)
125	+	{
126	+	dlinkDelete(&request->node, &request_list);
127	+
128	+	MyFree(request->name);
129	+	mp_pool_release(request);
130	+	}
131	+
132	+	/*
133	+	* make_request - Create a DNS request record for the server.
134	+	*/
135	+	static struct reslist *
136	+	make_request(dns_callback_fnc callback, void *ctx)
137	+	{
138	+	struct reslist *request = mp_pool_get(dns_pool);
139	+
140	+	request->sentat       = CurrentTime;
141	+	request->retries      = 2;
142	+	request->resend       = 1;
143	+	request->timeout      = 4;  /* Start at 4 and exponential inc. */
144	+	request->state        = REQ_IDLE;
145	+	request->callback     = callback;
146	+	request->callback_ctx = ctx;
147	+
148	+	dlinkAdd(request, &request->node, &request_list);
149	+	return request;
150	+	}
151
152		/*
153		* int
#	Line 159 | Line 178 | res_ourserver(const struct irc_ssaddr *i
178		#endif
179		v4 = (const struct sockaddr_in *)srv;
180
181	<	/* could probably just memcmp(srv, inp, srv.ss_len) here
181	>	/*
182	>	* Could probably just memcmp(srv, inp, srv.ss_len) here
183		* but we'll air on the side of caution - stu
164	–	*
184		*/
185		switch (srv->ss.ss_family)
186		{
#	Line 189 | Line 208 | res_ourserver(const struct irc_ssaddr *i
208		}
209
210		/*
192	–	* timeout_query_list - Remove queries from the list which have been
193	–	* there too long without being resolved.
194	–	*/
195	–	static time_t
196	–	timeout_query_list(void)
197	–	{
198	–	dlink_node *ptr = NULL, *ptr_next = NULL;
199	–	struct reslist *request = NULL;
200	–	time_t next_time = 0;
201	–	time_t timeout   = 0;
202	–
203	–	DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
204	–	{
205	–	request = ptr->data;
206	–	timeout = request->sentat + request->timeout;
207	–
208	–	if (CurrentTime >= timeout)
209	–	{
210	–	if (--request->retries <= 0)
211	–	{
212	–	(*request->callback)(request->callback_ctx, NULL, NULL);
213	–	rem_request(request);
214	–	continue;
215	–	}
216	–	else
217	–	{
218	–	request->sentat = CurrentTime;
219	–	request->timeout += request->timeout;
220	–	resend_query(request);
221	–	}
222	–	}
223	–
224	–	if ((next_time == 0) || timeout < next_time)
225	–	next_time = timeout;
226	–	}
227	–
228	–	return (next_time > CurrentTime) ? next_time : (CurrentTime + AR_TTL);
229	–	}
230	–
231	–	/*
232	–	* timeout_resolver - check request list
233	–	*/
234	–	static void
235	–	timeout_resolver(void *notused)
236	–	{
237	–	timeout_query_list();
238	–	}
239	–
240	–	/*
211		* start_resolver - do everything we need to read the resolv.conf file
212		* and initialize the resolver file descriptor if needed
213		*/
#	Line 258 | Line 228 | start_resolver(void)
228		}
229
230		/*
261	–	* init_resolver - initialize resolver and resolver library
262	–	*/
263	–	void
264	–	init_resolver(void)
265	–	{
266	–	static struct event event_timeout_resolver =
267	–	{
268	–	.name = "timeout_resolver",
269	–	.handler = timeout_resolver,
270	–	.when = 1
271	–	};
272	–
273	–	dns_pool = mp_pool_new(sizeof(struct reslist), MP_CHUNK_SIZE_DNS);
274	–	memset(&ResolverFileDescriptor, 0, sizeof(fde_t));
275	–	start_resolver();
276	–
277	–	event_add(&event_timeout_resolver, NULL);
278	–	}
279	–
280	–	/*
231		* restart_resolver - reread resolv.conf, reopen socket
232		*/
233		void
#	Line 288 | Line 238 | restart_resolver(void)
238		}
239
240		/*
291	–	* rem_request - remove a request from the list.
292	–	* This must also free any memory that has been allocated for
293	–	* temporary storage of DNS results.
294	–	*/
295	–	static void
296	–	rem_request(struct reslist *request)
297	–	{
298	–	dlinkDelete(&request->node, &request_list);
299	–
300	–	MyFree(request->name);
301	–	mp_pool_release(request);
302	–	}
303	–
304	–	/*
305	–	* make_request - Create a DNS request record for the server.
306	–	*/
307	–	static struct reslist *
308	–	make_request(dns_callback_fnc callback, void *ctx)
309	–	{
310	–	struct reslist *request = mp_pool_get(dns_pool);
311	–
312	–	request->sentat       = CurrentTime;
313	–	request->retries      = 2;
314	–	request->resend       = 1;
315	–	request->timeout      = 4;  /* Start at 4 and exponential inc. */
316	–	request->state        = REQ_IDLE;
317	–	request->callback     = callback;
318	–	request->callback_ctx = ctx;
319	–
320	–	dlinkAdd(request, &request->node, &request_list);
321	–	return request;
322	–	}
323	–
324	–	/*
241		* delete_resolver_queries - cleanup outstanding queries
242		* for which there no longer exist clients or conf lines.
243		*/
#	Line 343 | Line 259 | delete_resolver_queries(const void *vptr
259		* send_res_msg - sends msg to all nameservers found in the "_res" structure.
260		* This should reflect /etc/resolv.conf. We will get responses
261		* which arent needed but is easier than checking to see if nameserver
262	<	* isnt present. Returns number of messages successfully sent to
262	>	* isn't present. Returns number of messages successfully sent to
263		* nameservers or -1 if no successful sends.
264		*/
265		static int
#	Line 389 | Line 305 | find_id(int id)
305		}
306
307		/*
308	<	* gethost_byname_type - get host address from name
393	<	*
308	>	* query_name - generate a query based on class, type and name.
309		*/
310	<	void
311	<	gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type)
310	>	static void
311	>	query_name(const char *name, int query_class, int type,
312	>	struct reslist *request)
313		{
314	<	assert(name);
315	<	do_query_name(callback, ctx, name, NULL, type);
400	<	}
314	>	char buf[MAXPACKET];
315	>	int request_len = 0;
316
317	<	/*
403	<	* gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
404	<	*/
405	<	void
406	<	gethost_byname(dns_callback_fnc callback, void *ctx, const char *name)
407	<	{
408	<	#ifdef IPV6
409	<	gethost_byname_type(callback, ctx, name, T_AAAA);
410	<	#else
411	<	gethost_byname_type(callback, ctx, name, T_A);
412	<	#endif
413	<	}
317	>	memset(buf, 0, sizeof(buf));
318
319	<	/*
320	<	* gethost_byaddr - get host name from address
321	<	*/
322	<	void
323	<	gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr)
324	<	{
325	<	do_query_number(callback, ctx, addr, NULL);
319	>	if ((request_len = irc_res_mkquery(name, query_class, type,
320	>	(unsigned char *)buf, sizeof(buf))) > 0)
321	>	{
322	>	HEADER *header = (HEADER *)buf;
323	>
324	>	/*
325	>	* Generate an unique id.
326	>	* NOTE: we don't have to worry about converting this to and from
327	>	* network byte order, the nameserver does not interpret this value
328	>	* and returns it unchanged.
329	>	*/
330	>	do
331	>	header->id = (header->id + genrand_int32()) & 0xFFFF;
332	>	while (find_id(header->id));
333	>
334	>	request->id = header->id;
335	>	++request->sends;
336	>
337	>	request->sent += send_res_msg(buf, request_len, request->sends);
338	>	}
339		}
340
341		/*
#	Line 508 | Line 425 | do_query_number(dns_callback_fnc callbac
425		}
426
427		/*
428	<	* query_name - generate a query based on class, type and name.
428	>	* gethost_byname_type - get host address from name
429	>	*
430		*/
431	<	static void
432	<	query_name(const char *name, int query_class, int type,
515	<	struct reslist *request)
431	>	void
432	>	gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type)
433		{
434	<	char buf[MAXPACKET];
435	<	int request_len = 0;
436	<
520	<	memset(buf, 0, sizeof(buf));
521	<
522	<	if ((request_len = irc_res_mkquery(name, query_class, type,
523	<	(unsigned char *)buf, sizeof(buf))) > 0)
524	<	{
525	<	HEADER *header = (HEADER *)buf;
526	<
527	<	/*
528	<	* generate an unique id
529	<	* NOTE: we don't have to worry about converting this to and from
530	<	* network byte order, the nameserver does not interpret this value
531	<	* and returns it unchanged
532	<	*/
533	<	do
534	<	header->id = (header->id + genrand_int32()) & 0xffff;
535	<	while (find_id(header->id));
434	>	assert(name);
435	>	do_query_name(callback, ctx, name, NULL, type);
436	>	}
437
438	<	request->id = header->id;
439	<	++request->sends;
438	>	/*
439	>	* gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
440	>	*/
441	>	void
442	>	gethost_byname(dns_callback_fnc callback, void *ctx, const char *name)
443	>	{
444	>	#ifdef IPV6
445	>	gethost_byname_type(callback, ctx, name, T_AAAA);
446	>	#else
447	>	gethost_byname_type(callback, ctx, name, T_A);
448	>	#endif
449	>	}
450
451	<	request->sent += send_res_msg(buf, request_len, request->sends);
452	<	}
451	>	/*
452	>	* gethost_byaddr - get host name from address
453	>	*/
454	>	void
455	>	gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr)
456	>	{
457	>	do_query_number(callback, ctx, addr, NULL);
458		}
459
460		static void
#	Line 556 | Line 472 | resend_query(struct reslist *request)
472		do_query_name(NULL, NULL, request->name, request, request->type);
473		break;
474		#ifdef IPV6
475	<	case T_AAAA:
560	<	/* didnt work, try A */
475	>	case T_AAAA:  /* Didn't work, try A */
476		if (request->state == REQ_AAAA)
477		do_query_name(NULL, NULL, request->name, request, T_A);
478		#endif
#	Line 574 | Line 489 | proc_answer(struct reslist *request, HEA
489		{
490		char hostbuf[HOSTLEN + 100]; /* working buffer */
491		unsigned char *current;      /* current position in buf */
577	–	int query_class;             /* answer class */
492		int type;                    /* answer type */
493		int n;                       /* temp count */
494		int rd_length;
#	Line 593 | Line 507 | proc_answer(struct reslist *request, HEA
507		}
508
509		/*
510	<	* process each answer sent to us blech.
510	>	* Process each answer sent to us blech.
511		*/
512		while (header->ancount > 0 && (char *)current < eob)
513		{
#	Line 602 | Line 516 | proc_answer(struct reslist *request, HEA
516		n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
517		hostbuf, sizeof(hostbuf));
518
519	<	if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
519	>	if (n < 0  /* Broken message */ || n == 0  /* No more answers left */)
520		return 0;
521
522		hostbuf[HOSTLEN] = '\0';
523
524	<	/* With Address arithmetic you have to be very anal
524	>	/*
525	>	* With Address arithmetic you have to be very anal
526		* this code was not working on alpha due to that
527		* (spotted by rodder/jailbird/dianora)
528		*/
#	Line 618 | Line 533 | proc_answer(struct reslist *request, HEA
533
534		type = irc_ns_get16(current);
535		current += TYPE_SIZE;
621	–
622	–	query_class = irc_ns_get16(current);
536		current += CLASS_SIZE;
624	–
625	–	request->ttl = irc_ns_get32(current);
537		current += TTL_SIZE;
627	–
538		rd_length = irc_ns_get16(current);
539		current += RDLENGTH_SIZE;
540
#	Line 670 | Line 580 | proc_answer(struct reslist *request, HEA
580
581		n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
582		current, hostbuf, sizeof(hostbuf));
583	<	if (n < 0 /* Broken message */ || n == 0 /* No more answers left */)
583	>	if (n < 0  /* Broken message */ || n == 0  /* No more answers left */)
584		return 0;
585
586		strlcpy(request->name, hostbuf, HOSTLEN + 1);
587		return 1;
588		break;
589	<	case T_CNAME: /* first check we already havent started looking
680	<	into a cname */
589	>	case T_CNAME:  /* First check we already haven't started looking into a cname */
590		if (request->type != T_PTR)
591		return 0;
592
#	Line 714 | Line 623 | proc_answer(struct reslist *request, HEA
623		static void
624		res_readreply(fde_t *fd, void *data)
625		{
626	<	char buf[sizeof(HEADER) + MAXPACKET]
718	<	/* Sparc and alpha need 16bit-alignment for accessing header->id
719	<	* (which is uint16_t). Because of the header = (HEADER*) buf;
720	<	* lateron, this is neeeded. --FaUl
721	<	*/
722	<	#if defined(__sparc__) || defined(__alpha__)
723	<	__attribute__((aligned (16)))
724	<	#endif
725	<	;
626	>	char buf[sizeof(HEADER) + MAXPACKET];
627		HEADER *header;
628		struct reslist *request = NULL;
629	<	int rc;
629	>	ssize_t rc = 0;
630		socklen_t len = sizeof(struct irc_ssaddr);
631		struct irc_ssaddr lsin;
632
633		rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len);
634
635	<	/* Re-schedule a read *after* recvfrom, or we'll be registering
635	>	/*
636	>	* Re-schedule a read *after* recvfrom, or we'll be registering
637		* interest where it'll instantly be ready for read :-) -- adrian
638		*/
639		comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0);
640
641	<	/* Better to cast the sizeof instead of rc */
642	<	if (rc <= (int)(sizeof(HEADER)))
641	>	if (rc <= (ssize_t)sizeof(HEADER))
642	>	return;
643	>
644	>	/*
645	>	* Check against possibly fake replies
646	>	*/
647	>	if (!res_ourserver(&lsin))
648		return;
649
650		/*
#	Line 750 | Line 657 | res_readreply(fde_t *fd, void *data)
657		header->arcount = ntohs(header->arcount);
658
659		/*
753	–	* Check against possibly fake replies
754	–	*/
755	–	if (!res_ourserver(&lsin))
756	–	return;
757	–
758	–	/*
660		* Response for an id which we have already received an answer for
661		* just ignore this response.
662		*/
663	<	if (!(request = find_id(header->id)))
663	>	if ((request = find_id(header->id)) == NULL)
664		return;
665
666		if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
#	Line 777 | Line 678 | res_readreply(fde_t *fd, void *data)
678		else
679		{
680		/*
681	<	* If we havent already tried this, and we're looking up AAAA, try A
781	<	* now
681	>	* If we havent already tried this, and we're looking up AAAA, try A now.
682		*/
683		if (request->state == REQ_AAAA && request->type == T_AAAA)
684		{
#	Line 856 | Line 756 | report_dns_servers(struct Client *source
756		sendto_one_numeric(source_p, &me, RPL_STATSALINE, ipaddr);
757		}
758		}
759	+
760	+	/*
761	+	* timeout_query_list - Remove queries from the list which have been
762	+	* there too long without being resolved.
763	+	*/
764	+	static time_t
765	+	timeout_query_list(void)
766	+	{
767	+	dlink_node *ptr = NULL, *ptr_next = NULL;
768	+	struct reslist *request = NULL;
769	+	time_t next_time = 0;
770	+	time_t timeout   = 0;
771	+
772	+	DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head)
773	+	{
774	+	request = ptr->data;
775	+	timeout = request->sentat + request->timeout;
776	+
777	+	if (CurrentTime >= timeout)
778	+	{
779	+	if (--request->retries <= 0)
780	+	{
781	+	(*request->callback)(request->callback_ctx, NULL, NULL);
782	+	rem_request(request);
783	+	continue;
784	+	}
785	+	else
786	+	{
787	+	request->sentat = CurrentTime;
788	+	request->timeout += request->timeout;
789	+	resend_query(request);
790	+	}
791	+	}
792	+
793	+	if (next_time == 0 || timeout < next_time)
794	+	next_time = timeout;
795	+	}
796	+
797	+	return (next_time > CurrentTime) ? next_time : (CurrentTime + AR_TTL);
798	+	}
799	+
800	+	/*
801	+	* timeout_resolver - check request list
802	+	*/
803	+	static void
804	+	timeout_resolver(void *notused)
805	+	{
806	+	timeout_query_list();
807	+	}
808	+
809	+	/*
810	+	* init_resolver - initialize resolver and resolver library
811	+	*/
812	+	void
813	+	init_resolver(void)
814	+	{
815	+	static struct event event_timeout_resolver =
816	+	{
817	+	.name = "timeout_resolver",
818	+	.handler = timeout_resolver,
819	+	.when = 1
820	+	};
821	+
822	+	dns_pool = mp_pool_new(sizeof(struct reslist), MP_CHUNK_SIZE_DNS);
823	+	memset(&ResolverFileDescriptor, 0, sizeof(fde_t));
824	+	start_resolver();
825	+
826	+	event_add(&event_timeout_resolver, NULL);
827	+	}

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