2 * A rewrite of Darren Reeds original res.c As there is nothing
3 * left of Darrens original code, this is now licensed by the hybrid group.
4 * (Well, some of the function names are the same, and bits of the structs..)
5 * You can use it where it is useful, free even. Buy us a beer and stuff.
7 * The authors takes no responsibility for any damage or loss
8 * of property which results from the use of this software.
10 * July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
11 * added callbacks and reference counting of returned hostents.
12 * --Bleep (Thomas Helvey <tomh@inxpress.net>)
14 * This was all needlessly complicated for irc. Simplified. No more hostent
15 * All we really care about is the IP -> hostname mappings. Thats all.
17 * Apr 28, 2003 --cryogen and Dianora
19 * DNS server flooding lessened, AAAA-or-A lookup removed, ip6.int support
20 * removed, various robustness fixes
22 * 2006 --jilles and nenolod
24 * Resend queries to other servers if the DNS server replies with an error or
25 * an invalid response. Also, avoid servers that return errors or invalid
28 * October 2012 --mr_flea
30 * ircd-ratbox changes for random IDs merged back in.
32 * January 2016 --kaniini
41 #error this code needs to be able to address individual octets
44 static PF res_readreply
;
46 #define MAXPACKET 1024 /* rfc sez 512 but we expand names so ... */
47 #define RES_MAXALIASES 35 /* maximum aliases allowed */
48 #define RES_MAXADDRS 35 /* maximum addresses allowed */
49 #define AR_TTL 600 /* TTL in seconds for dns cache entries */
51 /* RFC 1104/1105 wasn't very helpful about what these fields
52 * should be named, so for now, we'll just name them this way.
53 * we probably should look at what named calls them or something.
55 #define TYPE_SIZE (size_t)2
56 #define CLASS_SIZE (size_t)2
57 #define TTL_SIZE (size_t)4
58 #define RDLENGTH_SIZE (size_t)2
59 #define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)
62 struct in6_addr ipv6_addr
;
64 struct in_addr ipv4_addr
;
72 char queryname
[IRCD_RES_HOSTLEN
+ 1]; /* name currently being queried */
73 char retries
; /* retry counter */
74 char sends
; /* number of sends (>1 means resent) */
77 int lastns
; /* index of last server sent to */
78 struct rb_sockaddr_storage addr
;
80 struct DNSQuery
*query
; /* query callback for this request */
83 static rb_fde_t
*res_fd
;
84 static rb_dlink_list request_list
= { NULL
, NULL
, 0 };
85 static int ns_failure_count
[IRCD_MAXNS
]; /* timeouts and invalid/failed replies */
87 static void rem_request(struct reslist
*request
);
88 static struct reslist
*make_request(struct DNSQuery
*query
);
89 static void gethost_byname_type_fqdn(const char *name
, struct DNSQuery
*query
,
91 static void do_query_name(struct DNSQuery
*query
, const char *name
, struct reslist
*request
, int);
92 static void do_query_number(struct DNSQuery
*query
, const struct rb_sockaddr_storage
*,
93 struct reslist
*request
);
94 static void query_name(struct reslist
*request
);
95 static int send_res_msg(const char *buf
, int len
, int count
);
96 static void resend_query(struct reslist
*request
);
97 static int check_question(struct reslist
*request
, HEADER
* header
, char *buf
, char *eob
);
98 static int proc_answer(struct reslist
*request
, HEADER
* header
, char *, char *);
99 static struct reslist
*find_id(int id
);
100 static struct DNSReply
*make_dnsreply(struct reslist
*request
);
101 static int generate_random_port(void);
102 static uint16_t generate_random_id(void);
108 #define RES_MIN(a, b) ((a) < (b) ? (a) : (b))
111 random_socket(int family
)
117 struct rb_sockaddr_storage sockaddr
;
118 F
= rb_socket(family
, SOCK_DGRAM
, 0, "UDP resolver socket");
122 memset(&sockaddr
, 0, sizeof(sockaddr
));
124 SET_SS_FAMILY(&sockaddr
, family
);
127 if(family
== AF_INET6
)
129 struct sockaddr_in6
*in6
= (struct sockaddr_in6
*)&sockaddr
;
130 memcpy(&in6
->sin6_addr
, &ipv6_addr
, sizeof(struct in6_addr
));
131 len
= (rb_socklen_t
) sizeof(struct sockaddr_in6
);
136 struct sockaddr_in
*in
= (struct sockaddr_in
*)&sockaddr
;
137 in
->sin_addr
.s_addr
= ipv4_addr
.s_addr
;
138 len
= (rb_socklen_t
) sizeof(struct sockaddr_in
);
141 for(i
= 0; i
< 10; i
++)
143 nport
= htons(generate_random_port());
145 if(family
== AF_INET
)
146 ((struct sockaddr_in
*)&sockaddr
)->sin_port
= nport
;
149 ((struct sockaddr_in6
*)&sockaddr
)->sin6_port
= nport
;
152 if(bind(rb_get_fd(F
), (struct sockaddr
*)&sockaddr
, len
) == 0)
162 * looks up "inp" in irc_nsaddr_list[]
164 * server ID or -1 for not found
166 * paul vixie, 29may94
167 * revised for ircd, cryogen(stu) may03
168 * slightly modified for charybdis, mr_flea oct12
171 res_ourserver(const struct rb_sockaddr_storage
*inp
)
174 const struct sockaddr_in6
*v6
;
175 const struct sockaddr_in6
*v6in
= (const struct sockaddr_in6
*)inp
;
177 const struct sockaddr_in
*v4
;
178 const struct sockaddr_in
*v4in
= (const struct sockaddr_in
*)inp
;
181 for(ns
= 0; ns
< irc_nscount
; ns
++)
183 const struct rb_sockaddr_storage
*srv
= &irc_nsaddr_list
[ns
];
185 v6
= (const struct sockaddr_in6
*)srv
;
187 v4
= (const struct sockaddr_in
*)srv
;
189 /* could probably just memcmp(srv, inp, srv.ss_len) here
190 * but we'll air on the side of caution - stu
192 switch (GET_SS_FAMILY(srv
))
196 if(GET_SS_FAMILY(srv
) == GET_SS_FAMILY(inp
))
197 if(v6
->sin6_port
== v6in
->sin6_port
)
198 if((memcmp(&v6
->sin6_addr
.s6_addr
, &v6in
->sin6_addr
.s6_addr
,
199 sizeof(struct in6_addr
)) == 0) ||
200 (memcmp(&v6
->sin6_addr
.s6_addr
, &in6addr_any
,
201 sizeof(struct in6_addr
)) == 0))
206 if(GET_SS_FAMILY(srv
) == GET_SS_FAMILY(inp
))
207 if(v4
->sin_port
== v4in
->sin_port
)
208 if((v4
->sin_addr
.s_addr
== INADDR_ANY
)
209 || (v4
->sin_addr
.s_addr
== v4in
->sin_addr
.s_addr
))
221 * timeout_query_list - Remove queries from the list which have been
222 * there too long without being resolved.
224 static time_t timeout_query_list(time_t now
)
227 rb_dlink_node
*next_ptr
;
228 struct reslist
*request
;
229 time_t next_time
= 0;
232 RB_DLINK_FOREACH_SAFE(ptr
, next_ptr
, request_list
.head
)
235 timeout
= request
->sentat
+ request
->timeout
;
239 ns_failure_count
[request
->lastns
]++;
240 request
->sentat
= now
;
241 request
->timeout
+= request
->timeout
;
242 resend_query(request
);
245 if ((next_time
== 0) || timeout
< next_time
)
251 return (next_time
> now
) ? next_time
: (now
+ AR_TTL
);
255 * timeout_resolver - check request list
257 static void timeout_resolver(void *notused
)
259 timeout_query_list(rb_current_time());
262 static struct ev_entry
*timeout_resolver_ev
= NULL
;
265 * start_resolver - do everything we need to read the resolv.conf file
266 * and initialize the resolver file descriptor if needed
268 static void start_resolver(void)
273 for (i
= 0; i
< irc_nscount
; i
++)
274 ns_failure_count
[i
] = 0;
278 if ((res_fd
= rb_socket(GET_SS_FAMILY(&irc_nsaddr_list
[0]), SOCK_DGRAM
, 0,
279 "UDP resolver socket")) == NULL
)
282 /* At the moment, the resolver FD data is global .. */
283 rb_setselect(res_fd
, RB_SELECT_READ
, res_readreply
, NULL
);
284 timeout_resolver_ev
= rb_event_add("timeout_resolver", timeout_resolver
, NULL
, 1);
289 * init_resolver - initialize resolver and resolver library
291 void init_resolver(void)
294 srand48(rb_current_time());
300 * restart_resolver - reread resolv.conf, reopen socket
302 void restart_resolver(void)
306 rb_event_delete(timeout_resolver_ev
); /* -ddosen */
311 * add_local_domain - Add the domain to hostname, if it is missing
312 * (as suggested by eps@TOASTER.SFSU.EDU)
314 void add_local_domain(char *hname
, size_t size
)
316 /* try to fix up unqualified names */
317 if (strchr(hname
, '.') == NULL
)
321 size_t len
= strlen(hname
);
323 if ((strlen(irc_domain
) + len
+ 2) < size
)
326 strcpy(hname
+ len
, irc_domain
);
333 * rem_request - remove a request from the list.
334 * This must also free any memory that has been allocated for
335 * temporary storage of DNS results.
337 static void rem_request(struct reslist
*request
)
339 rb_dlinkDelete(&request
->node
, &request_list
);
340 rb_free(request
->name
);
345 * make_request - Create a DNS request record for the server.
347 static struct reslist
*make_request(struct DNSQuery
*query
)
349 struct reslist
*request
= rb_malloc(sizeof(struct reslist
));
351 request
->sentat
= rb_current_time();
352 request
->retries
= 3;
353 request
->timeout
= 4; /* start at 4 and exponential inc. */
354 request
->query
= query
;
357 * generate a unique id
358 * NOTE: we don't have to worry about converting this to and from
359 * network byte order, the nameserver does not interpret this value
360 * and returns it unchanged
362 * we generate an id per request now (instead of per send) to allow
363 * late replies to be used.
365 request
->id
= generate_random_id();
367 rb_dlinkAdd(request
, &request
->node
, &request_list
);
373 * retryfreq - determine how many queries to wait before resending
374 * if there have been that many consecutive timeouts
376 static int retryfreq(int timeouts
)
394 * send_res_msg - sends msg to a nameserver.
395 * This should reflect /etc/resolv.conf.
396 * Returns number of nameserver successfully sent to
397 * or -1 if no successful sends.
399 static int send_res_msg(const char *msg
, int len
, int rcount
)
406 /* First try a nameserver that seems to work.
407 * Every once in a while, try a possibly broken one to check
408 * if it is working again.
410 for (i
= 0; i
< irc_nscount
; i
++)
412 ns
= (i
+ rcount
- 1) % irc_nscount
;
413 if (ns_failure_count
[ns
] && retrycnt
% retryfreq(ns_failure_count
[ns
]))
415 if (sendto(rb_get_fd(res_fd
), msg
, len
, 0,
416 (struct sockaddr
*)&(irc_nsaddr_list
[ns
]),
417 GET_SS_LEN(&irc_nsaddr_list
[ns
])) == len
)
421 /* No known working nameservers, try some broken one. */
422 for (i
= 0; i
< irc_nscount
; i
++)
424 ns
= (i
+ rcount
- 1) % irc_nscount
;
425 if (!ns_failure_count
[ns
])
427 if (sendto(rb_get_fd(res_fd
), msg
, len
, 0,
428 (struct sockaddr
*)&(irc_nsaddr_list
[ns
]),
429 GET_SS_LEN(&irc_nsaddr_list
[ns
])) == len
)
437 * find_id - find a dns request id (id is determined by dn_mkquery)
439 static struct reslist
*find_id(int id
)
442 struct reslist
*request
;
444 RB_DLINK_FOREACH(ptr
, request_list
.head
)
448 if (request
->id
== id
)
456 generate_random_id(void)
462 rb_get_random(&id
, sizeof(id
));
471 generate_random_port(void)
477 rb_get_random(&port
, sizeof(port
));
485 * gethost_byname_type - get host address from name, adding domain if needed
487 void gethost_byname_type(const char *name
, struct DNSQuery
*query
, int type
)
489 char fqdn
[IRCD_RES_HOSTLEN
+ 1];
492 rb_strlcpy(fqdn
, name
, sizeof fqdn
);
493 add_local_domain(fqdn
, IRCD_RES_HOSTLEN
);
494 gethost_byname_type_fqdn(fqdn
, query
, type
);
498 * gethost_byname_type_fqdn - get host address from fqdn
500 static void gethost_byname_type_fqdn(const char *name
, struct DNSQuery
*query
,
504 do_query_name(query
, name
, NULL
, type
);
508 * gethost_byaddr - get host name from address
510 void gethost_byaddr(const struct rb_sockaddr_storage
*addr
, struct DNSQuery
*query
)
512 do_query_number(query
, addr
, NULL
);
516 * do_query_name - nameserver lookup name
518 static void do_query_name(struct DNSQuery
*query
, const char *name
, struct reslist
*request
,
523 request
= make_request(query
);
524 request
->name
= rb_strdup(name
);
527 rb_strlcpy(request
->queryname
, name
, sizeof(request
->queryname
));
528 request
->type
= type
;
533 * do_query_number - Use this to do reverse IP# lookups.
535 static void do_query_number(struct DNSQuery
*query
, const struct rb_sockaddr_storage
*addr
,
536 struct reslist
*request
)
538 const unsigned char *cp
;
542 request
= make_request(query
);
543 memcpy(&request
->addr
, addr
, sizeof(struct rb_sockaddr_storage
));
544 request
->name
= (char *)rb_malloc(IRCD_RES_HOSTLEN
+ 1);
547 if (GET_SS_FAMILY(addr
) == AF_INET
)
549 const struct sockaddr_in
*v4
= (const struct sockaddr_in
*)addr
;
550 cp
= (const unsigned char *)&v4
->sin_addr
.s_addr
;
552 sprintf(request
->queryname
, "%u.%u.%u.%u.in-addr.arpa", (unsigned int)(cp
[3]),
553 (unsigned int)(cp
[2]), (unsigned int)(cp
[1]), (unsigned int)(cp
[0]));
556 else if (GET_SS_FAMILY(addr
) == AF_INET6
)
558 const struct sockaddr_in6
*v6
= (const struct sockaddr_in6
*)addr
;
559 cp
= (const unsigned char *)&v6
->sin6_addr
.s6_addr
;
561 (void)sprintf(request
->queryname
, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
562 "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa",
563 (unsigned int)(cp
[15] & 0xf), (unsigned int)(cp
[15] >> 4),
564 (unsigned int)(cp
[14] & 0xf), (unsigned int)(cp
[14] >> 4),
565 (unsigned int)(cp
[13] & 0xf), (unsigned int)(cp
[13] >> 4),
566 (unsigned int)(cp
[12] & 0xf), (unsigned int)(cp
[12] >> 4),
567 (unsigned int)(cp
[11] & 0xf), (unsigned int)(cp
[11] >> 4),
568 (unsigned int)(cp
[10] & 0xf), (unsigned int)(cp
[10] >> 4),
569 (unsigned int)(cp
[9] & 0xf), (unsigned int)(cp
[9] >> 4),
570 (unsigned int)(cp
[8] & 0xf), (unsigned int)(cp
[8] >> 4),
571 (unsigned int)(cp
[7] & 0xf), (unsigned int)(cp
[7] >> 4),
572 (unsigned int)(cp
[6] & 0xf), (unsigned int)(cp
[6] >> 4),
573 (unsigned int)(cp
[5] & 0xf), (unsigned int)(cp
[5] >> 4),
574 (unsigned int)(cp
[4] & 0xf), (unsigned int)(cp
[4] >> 4),
575 (unsigned int)(cp
[3] & 0xf), (unsigned int)(cp
[3] >> 4),
576 (unsigned int)(cp
[2] & 0xf), (unsigned int)(cp
[2] >> 4),
577 (unsigned int)(cp
[1] & 0xf), (unsigned int)(cp
[1] >> 4),
578 (unsigned int)(cp
[0] & 0xf), (unsigned int)(cp
[0] >> 4));
582 request
->type
= T_PTR
;
587 * query_name - generate a query based on class, type and name.
589 static void query_name(struct reslist
*request
)
595 memset(buf
, 0, sizeof(buf
));
598 irc_res_mkquery(request
->queryname
, C_IN
, request
->type
, (unsigned char *)buf
, sizeof(buf
))) > 0)
600 HEADER
*header
= (HEADER
*)(void *)buf
;
601 header
->id
= request
->id
;
604 ns
= send_res_msg(buf
, request_len
, request
->sends
);
606 request
->lastns
= ns
;
610 static void resend_query(struct reslist
*request
)
612 if (--request
->retries
<= 0)
614 (*request
->query
->callback
) (request
->query
->ptr
, NULL
);
615 rem_request(request
);
619 switch (request
->type
)
622 do_query_number(NULL
, &request
->addr
, request
);
628 do_query_name(NULL
, request
->name
, request
, request
->type
);
636 * check_question - check if the reply really belongs to the
637 * name we queried (to guard against late replies from previous
638 * queries with the same id).
640 static int check_question(struct reslist
*request
, HEADER
* header
, char *buf
, char *eob
)
642 char hostbuf
[IRCD_RES_HOSTLEN
+ 1]; /* working buffer */
643 unsigned char *current
; /* current position in buf */
644 int n
; /* temp count */
646 current
= (unsigned char *)buf
+ sizeof(HEADER
);
647 if (header
->qdcount
!= 1)
649 n
= irc_dn_expand((unsigned char *)buf
, (unsigned char *)eob
, current
, hostbuf
,
653 if (strcasecmp(hostbuf
, request
->queryname
))
659 * proc_answer - process name server reply
661 static int proc_answer(struct reslist
*request
, HEADER
* header
, char *buf
, char *eob
)
663 char hostbuf
[IRCD_RES_HOSTLEN
+ 100]; /* working buffer */
664 unsigned char *current
; /* current position in buf */
665 int type
; /* answer type */
666 int n
; /* temp count */
668 struct sockaddr_in
*v4
; /* conversion */
670 struct sockaddr_in6
*v6
;
672 current
= (unsigned char *)buf
+ sizeof(HEADER
);
674 for (; header
->qdcount
> 0; --header
->qdcount
)
676 if ((n
= irc_dn_skipname(current
, (unsigned char *)eob
)) < 0)
679 current
+= (size_t) n
+ QFIXEDSZ
;
683 * process each answer sent to us blech.
685 while (header
->ancount
> 0 && (char *)current
< eob
)
689 n
= irc_dn_expand((unsigned char *)buf
, (unsigned char *)eob
, current
, hostbuf
,
702 * no more answers left
707 hostbuf
[IRCD_RES_HOSTLEN
] = '\0';
709 /* With Address arithmetic you have to be very anal
710 * this code was not working on alpha due to that
711 * (spotted by rodder/jailbird/dianora)
713 current
+= (size_t) n
;
715 if (!(((char *)current
+ ANSWER_FIXED_SIZE
) < eob
))
718 type
= irc_ns_get16(current
);
719 current
+= TYPE_SIZE
;
721 (void) irc_ns_get16(current
);
722 current
+= CLASS_SIZE
;
724 request
->ttl
= irc_ns_get32(current
);
727 rd_length
= irc_ns_get16(current
);
728 current
+= RDLENGTH_SIZE
;
731 * Wait to set request->type until we verify this structure
736 if (request
->type
!= T_A
)
740 * check for invalid rd_length or too many addresses
742 if (rd_length
!= sizeof(struct in_addr
))
744 v4
= (struct sockaddr_in
*)&request
->addr
;
745 SET_SS_LEN(&request
->addr
, sizeof(struct sockaddr_in
));
746 v4
->sin_family
= AF_INET
;
747 memcpy(&v4
->sin_addr
, current
, sizeof(struct in_addr
));
752 if (request
->type
!= T_AAAA
)
754 if (rd_length
!= sizeof(struct in6_addr
))
756 SET_SS_LEN(&request
->addr
, sizeof(struct sockaddr_in6
));
757 v6
= (struct sockaddr_in6
*)&request
->addr
;
758 v6
->sin6_family
= AF_INET6
;
759 memcpy(&v6
->sin6_addr
, current
, sizeof(struct in6_addr
));
764 if (request
->type
!= T_PTR
)
766 n
= irc_dn_expand((unsigned char *)buf
, (unsigned char *)eob
, current
,
767 hostbuf
, sizeof(hostbuf
));
769 return (0); /* broken message */
771 return (0); /* no more answers left */
773 rb_strlcpy(request
->name
, hostbuf
, IRCD_RES_HOSTLEN
+ 1);
778 /* real answer will follow */
779 current
+= rd_length
;
791 * res_read_single_reply - read a dns reply from the nameserver and process it.
792 * Return value: 1 if a packet was read, 0 otherwise
794 static int res_read_single_reply(rb_fde_t
*F
, void *data
)
796 char buf
[sizeof(HEADER
) + MAXPACKET
]
797 /* Sparc and alpha need 16bit-alignment for accessing header->id
798 * (which is uint16_t). Because of the header = (HEADER*) buf;
799 * lateron, this is neeeded. --FaUl
801 #if defined(__sparc__) || defined(__alpha__)
802 __attribute__ ((aligned(16)))
806 struct reslist
*request
= NULL
;
807 struct DNSReply
*reply
= NULL
;
810 socklen_t len
= sizeof(struct rb_sockaddr_storage
);
811 struct rb_sockaddr_storage lsin
;
814 rc
= recvfrom(rb_get_fd(F
), buf
, sizeof(buf
), 0, (struct sockaddr
*)&lsin
, &len
);
817 if (rc
== 0 || rc
== -1)
821 if (rc
<= (int)(sizeof(HEADER
)))
825 * convert DNS reply reader from Network byte order to CPU byte order.
827 header
= (HEADER
*)(void *)buf
;
828 header
->ancount
= ntohs(header
->ancount
);
829 header
->qdcount
= ntohs(header
->qdcount
);
830 header
->nscount
= ntohs(header
->nscount
);
831 header
->arcount
= ntohs(header
->arcount
);
834 * response for an id which we have already received an answer for
835 * just ignore this response.
837 if (0 == (request
= find_id(header
->id
)))
841 * check against possibly fake replies
843 ns
= res_ourserver(&lsin
);
847 if (ns
!= request
->lastns
)
850 * We'll accept the late reply, but penalize it a little more to make
851 * sure a laggy server doesn't end up favored.
853 ns_failure_count
[ns
] += 3;
857 if (!check_question(request
, header
, buf
, buf
+ rc
))
860 if ((header
->rcode
!= NO_ERRORS
) || (header
->ancount
== 0))
863 * RFC 2136 states that in the event of a server returning SERVFAIL
864 * or NOTIMP, the request should be resent to the next server.
865 * Additionally, if the server refuses our query, resend it as well.
868 if (SERVFAIL
== header
->rcode
|| NOTIMP
== header
->rcode
||
869 REFUSED
== header
->rcode
)
871 ns_failure_count
[ns
]++;
872 resend_query(request
);
877 * Either a fatal error was returned or no answer. Cancel the
880 if (NXDOMAIN
== header
->rcode
)
882 /* If the rcode is NXDOMAIN, treat it as a good response. */
883 ns_failure_count
[ns
] /= 4;
885 (*request
->query
->callback
) (request
->query
->ptr
, NULL
);
886 rem_request(request
);
891 * If this fails there was an error decoding the received packet.
894 answer_count
= proc_answer(request
, header
, buf
, buf
+ rc
);
898 if (request
->type
== T_PTR
)
900 if (request
->name
== NULL
)
903 * Got a PTR response with no name, something strange is
904 * happening. Try another DNS server.
906 ns_failure_count
[ns
]++;
907 resend_query(request
);
912 * Lookup the 'authoritative' name that we were given for the
916 if (GET_SS_FAMILY(&request
->addr
) == AF_INET6
)
917 gethost_byname_type_fqdn(request
->name
, request
->query
, T_AAAA
);
920 gethost_byname_type_fqdn(request
->name
, request
->query
, T_A
);
921 rem_request(request
);
926 * got a name and address response, client resolved
928 reply
= make_dnsreply(request
);
929 (*request
->query
->callback
) (request
->query
->ptr
, reply
);
931 rem_request(request
);
934 ns_failure_count
[ns
] /= 4;
938 /* Invalid or corrupt reply - try another resolver. */
939 ns_failure_count
[ns
]++;
940 resend_query(request
);
946 res_readreply(rb_fde_t
*F
, void *data
)
948 while (res_read_single_reply(F
, data
))
950 rb_setselect(F
, RB_SELECT_READ
, res_readreply
, NULL
);
953 static struct DNSReply
*
954 make_dnsreply(struct reslist
*request
)
957 lrb_assert(request
!= 0);
959 cp
= (struct DNSReply
*)rb_malloc(sizeof(struct DNSReply
));
961 cp
->h_name
= request
->name
;
962 memcpy(&cp
->addr
, &request
->addr
, sizeof(cp
->addr
));