4 * - TCP connection management
5 * - user-visible check/wait and event-loop-related functions
9 * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
11 * It is part of adns, which is
12 * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
13 * Copyright (C) 1999 Tony Finch <dot@dotat.at>
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2, or (at your option)
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software Foundation,
27 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
34 #include <sys/types.h>
37 #include <sys/socket.h>
38 #include <netinet/in.h>
39 #include <arpa/inet.h>
43 /* TCP connection management. */
45 void adns__tcp_closenext(adns_state ads
) {
49 close(ads
->tcpsocket
);
51 ads
->tcpstate
= server_disconnected
;
52 ads
->tcprecv
.used
= ads
->tcprecv_skip
= ads
->tcpsend
.used
= 0;
53 ads
->tcpserver
= (serv
+1)%ads
->nservers
;
56 void adns__tcp_broken(adns_state ads
, const char *what
, const char *why
) {
60 assert(ads
->tcpstate
== server_connecting
|| ads
->tcpstate
== server_ok
);
62 adns__warn(ads
,serv
,0,"TCP connection lost: %s: %s",what
,why
);
63 adns__tcp_closenext(ads
);
65 for (qu
= ads
->timew
.head
; qu
; qu
= nqu
) {
67 if (qu
->state
== query_tosend
) continue;
68 assert(qu
->state
== query_tcpwait
|| qu
->state
== query_tcpsent
);
69 qu
->state
= query_tcpwait
;
70 qu
->tcpfailed
|= (1<<serv
);
71 if (qu
->tcpfailed
== (1<<ads
->nservers
)-1) {
72 LIST_UNLINK(ads
->timew
,qu
);
73 adns__query_fail(qu
,adns_s_allservfail
);
78 static void tcp_connected(adns_state ads
, struct timeval now
) {
81 adns__debug(ads
,ads
->tcpserver
,0,"TCP connected");
82 ads
->tcpstate
= server_ok
;
83 for (qu
= ads
->timew
.head
; qu
; qu
= nqu
) {
85 if (qu
->state
== query_tosend
) continue;
86 assert (qu
->state
== query_tcpwait
);
87 adns__query_tcp(qu
,now
);
91 void adns__tcp_tryconnect(adns_state ads
, struct timeval now
) {
93 struct sockaddr_in addr
;
94 struct protoent
*proto
;
96 for (tries
=0; tries
<ads
->nservers
; tries
++) {
97 if (ads
->tcpstate
== server_connecting
|| ads
->tcpstate
== server_ok
) return;
98 assert(ads
->tcpstate
== server_disconnected
);
99 assert(!ads
->tcpsend
.used
);
100 assert(!ads
->tcprecv
.used
);
101 assert(!ads
->tcprecv_skip
);
103 proto
= getprotobyname("tcp");
104 if (!proto
) { adns__diag(ads
,-1,0,"unable to find protocol no. for TCP !"); return; }
105 fd
= socket(AF_INET
,SOCK_STREAM
,proto
->p_proto
);
107 adns__diag(ads
,-1,0,"cannot create TCP socket: %s",strerror(errno
));
110 r
= adns__setnonblock(ads
,fd
);
112 adns__diag(ads
,-1,0,"cannot make TCP socket nonblocking: %s",strerror(r
));
116 memset(&addr
,0,sizeof(addr
));
117 addr
.sin_family
= AF_INET
;
118 addr
.sin_port
= htons(DNS_PORT
);
119 addr
.sin_addr
= ads
->servers
[ads
->tcpserver
].addr
;
120 r
= connect(fd
,(const struct sockaddr
*)&addr
,sizeof(addr
));
122 ads
->tcpstate
= server_connecting
;
123 if (r
==0) { tcp_connected(ads
,now
); continue; }
124 if (errno
== EWOULDBLOCK
|| errno
== EINPROGRESS
) return;
125 adns__tcp_broken(ads
,"connect",strerror(errno
));
129 /* Timeout handling functions. */
131 void adns__must_gettimeofday(adns_state ads
, const struct timeval
**now_io
,
132 struct timeval
*tv_buf
) {
133 const struct timeval
*now
;
138 r
= gettimeofday(tv_buf
,0); if (!r
) { *now_io
= tv_buf
; return; }
139 adns__diag(ads
,-1,0,"gettimeofday failed: %s",strerror(errno
));
140 adns_globalsystemfailure(ads
);
144 static void inter_maxto(struct timeval
**tv_io
, struct timeval
*tvbuf
,
145 struct timeval maxto
) {
146 struct timeval
*rbuf
;
151 *tvbuf
= maxto
; *tv_io
= tvbuf
;
153 if (timercmp(rbuf
,&maxto
,>)) *rbuf
= maxto
;
155 /*fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n",
156 maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec);*/
159 static void inter_maxtoabs(struct timeval
**tv_io
, struct timeval
*tvbuf
,
160 struct timeval now
, struct timeval maxtime
) {
163 /*fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n",
164 now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec);*/
166 maxtime
.tv_sec
-= (now
.tv_sec
+2);
167 maxtime
.tv_usec
-= (now
.tv_usec
-2000000);
168 dr
= ldiv(maxtime
.tv_usec
,1000000);
169 maxtime
.tv_sec
+= dr
.quot
;
170 maxtime
.tv_usec
-= dr
.quot
*1000000;
171 if (maxtime
.tv_sec
<0) timerclear(&maxtime
);
172 inter_maxto(tv_io
,tvbuf
,maxtime
);
175 void adns__timeouts(adns_state ads
, int act
,
176 struct timeval
**tv_io
, struct timeval
*tvbuf
,
177 struct timeval now
) {
180 for (qu
= ads
->timew
.head
; qu
; qu
= nqu
) {
182 if (!timercmp(&now
,&qu
->timeout
,>)) {
183 if (!tv_io
) continue;
184 inter_maxtoabs(tv_io
,tvbuf
,now
,qu
->timeout
);
187 LIST_UNLINK(ads
->timew
,qu
);
188 if (qu
->state
!= query_tosend
) {
189 adns__query_fail(qu
,adns_s_timeout
);
191 adns__query_send(qu
,now
);
193 nqu
= ads
->timew
.head
;
198 void adns_firsttimeout(adns_state ads
,
199 struct timeval
**tv_io
, struct timeval
*tvbuf
,
200 struct timeval now
) {
201 adns__consistency(ads
,0,cc_entex
);
202 adns__timeouts(ads
, 0, tv_io
,tvbuf
, now
);
203 adns__consistency(ads
,0,cc_entex
);
206 void adns_processtimeouts(adns_state ads
, const struct timeval
*now
) {
207 struct timeval tv_buf
;
209 adns__consistency(ads
,0,cc_entex
);
210 adns__must_gettimeofday(ads
,&now
,&tv_buf
);
211 if (now
) adns__timeouts(ads
, 1, 0,0, *now
);
212 adns__consistency(ads
,0,cc_entex
);
215 /* fd handling functions. These are the top-level of the real work of
216 * reception and often transmission.
219 int adns__pollfds(adns_state ads
, struct pollfd pollfds_buf
[MAX_POLLFDS
]) {
220 /* Returns the number of entries filled in. Always zeroes revents. */
222 assert(MAX_POLLFDS
==2);
224 pollfds_buf
[0].fd
= ads
->udpsocket
;
225 pollfds_buf
[0].events
= POLLIN
;
226 pollfds_buf
[0].revents
= 0;
228 switch (ads
->tcpstate
) {
229 case server_disconnected
:
231 case server_connecting
:
232 pollfds_buf
[1].events
= POLLOUT
;
235 pollfds_buf
[1].events
= ads
->tcpsend
.used ? POLLIN
|POLLOUT
|POLLPRI
: POLLIN
|POLLPRI
;
240 pollfds_buf
[1].fd
= ads
->tcpsocket
;
244 int adns_processreadable(adns_state ads
, int fd
, const struct timeval
*now
) {
245 int want
, dgramlen
, r
, udpaddrlen
, serv
, old_skip
;
246 byte udpbuf
[DNS_MAXUDP
];
247 struct sockaddr_in udpaddr
;
249 adns__consistency(ads
,0,cc_entex
);
251 switch (ads
->tcpstate
) {
252 case server_disconnected
:
253 case server_connecting
:
256 if (fd
!= ads
->tcpsocket
) break;
257 assert(!ads
->tcprecv_skip
);
259 if (ads
->tcprecv
.used
>= ads
->tcprecv_skip
+2) {
260 dgramlen
= ((ads
->tcprecv
.buf
[ads
->tcprecv_skip
]<<8) |
261 ads
->tcprecv
.buf
[ads
->tcprecv_skip
+1]);
262 if (ads
->tcprecv
.used
>= ads
->tcprecv_skip
+2+dgramlen
) {
263 old_skip
= ads
->tcprecv_skip
;
264 ads
->tcprecv_skip
+= 2+dgramlen
;
265 adns__procdgram(ads
, ads
->tcprecv
.buf
+old_skip
+2,
266 dgramlen
, ads
->tcpserver
, 1,*now
);
274 ads
->tcprecv
.used
-= ads
->tcprecv_skip
;
275 memmove(ads
->tcprecv
.buf
,ads
->tcprecv
.buf
+ads
->tcprecv_skip
,ads
->tcprecv
.used
);
276 ads
->tcprecv_skip
= 0;
277 if (!adns__vbuf_ensure(&ads
->tcprecv
,want
)) { r
= ENOMEM
; goto xit
; }
278 assert(ads
->tcprecv
.used
<= ads
->tcprecv
.avail
);
279 if (ads
->tcprecv
.used
== ads
->tcprecv
.avail
) continue;
280 r
= read(ads
->tcpsocket
,
281 ads
->tcprecv
.buf
+ads
->tcprecv
.used
,
282 ads
->tcprecv
.avail
-ads
->tcprecv
.used
);
284 ads
->tcprecv
.used
+= r
;
287 if (errno
==EAGAIN
|| errno
==EWOULDBLOCK
) { r
= 0; goto xit
; }
288 if (errno
==EINTR
) continue;
289 if (errno_resources(errno
)) { r
= errno
; goto xit
; }
291 adns__tcp_broken(ads
,"read",r?
strerror(errno
):"closed");
294 } /* never reached */
298 if (fd
== ads
->udpsocket
) {
300 udpaddrlen
= sizeof(udpaddr
);
301 r
= recvfrom(ads
->udpsocket
,udpbuf
,sizeof(udpbuf
),0,
302 (struct sockaddr
*)&udpaddr
,&udpaddrlen
);
304 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
) { r
= 0; goto xit
; }
305 if (errno
== EINTR
) continue;
306 if (errno_resources(errno
)) { r
= errno
; goto xit
; }
307 adns__warn(ads
,-1,0,"datagram receive error: %s",strerror(errno
));
310 if (udpaddrlen
!= sizeof(udpaddr
)) {
311 adns__diag(ads
,-1,0,"datagram received with wrong address length %d"
312 " (expected %d)", udpaddrlen
,sizeof(udpaddr
));
315 if (udpaddr
.sin_family
!= AF_INET
) {
316 adns__diag(ads
,-1,0,"datagram received with wrong protocol family"
317 " %u (expected %u)",udpaddr
.sin_family
,AF_INET
);
320 if (ntohs(udpaddr
.sin_port
) != DNS_PORT
) {
321 adns__diag(ads
,-1,0,"datagram received from wrong port %u (expected %u)",
322 ntohs(udpaddr
.sin_port
),DNS_PORT
);
326 serv
< ads
->nservers
&&
327 ads
->servers
[serv
].addr
.s_addr
!= udpaddr
.sin_addr
.s_addr
;
329 if (serv
>= ads
->nservers
) {
330 adns__warn(ads
,-1,0,"datagram received from unknown nameserver %s",
331 inet_ntoa(udpaddr
.sin_addr
));
334 adns__procdgram(ads
,udpbuf
,r
,serv
,0,*now
);
339 adns__consistency(ads
,0,cc_entex
);
343 int adns_processwriteable(adns_state ads
, int fd
, const struct timeval
*now
) {
346 adns__consistency(ads
,0,cc_entex
);
348 switch (ads
->tcpstate
) {
349 case server_disconnected
:
351 case server_connecting
:
352 if (fd
!= ads
->tcpsocket
) break;
353 assert(ads
->tcprecv
.used
==0);
354 assert(ads
->tcprecv_skip
==0);
356 if (!adns__vbuf_ensure(&ads
->tcprecv
,1)) { r
= ENOMEM
; goto xit
; }
357 r
= read(ads
->tcpsocket
,&ads
->tcprecv
.buf
,1);
358 if (r
==0 || (r
<0 && (errno
==EAGAIN
|| errno
==EWOULDBLOCK
))) {
359 tcp_connected(ads
,*now
);
363 adns__tcp_broken(ads
,"connect/read","sent data before first request");
366 if (errno
==EINTR
) continue;
367 if (errno_resources(errno
)) { r
= errno
; goto xit
; }
368 adns__tcp_broken(ads
,"connect/read",strerror(errno
));
372 if (!(ads
->tcpsend
.used
&& fd
== ads
->tcpsocket
)) break;
374 adns__sigpipe_protect(ads
);
375 r
= write(ads
->tcpsocket
,ads
->tcpsend
.buf
,ads
->tcpsend
.used
);
376 adns__sigpipe_unprotect(ads
);
378 if (errno
==EINTR
) continue;
379 if (errno
==EAGAIN
|| errno
==EWOULDBLOCK
) { r
= 0; goto xit
; }
380 if (errno_resources(errno
)) { r
= errno
; goto xit
; }
381 adns__tcp_broken(ads
,"write",strerror(errno
));
384 ads
->tcpsend
.used
-= r
;
385 memmove(ads
->tcpsend
.buf
,ads
->tcpsend
.buf
+r
,ads
->tcpsend
.used
);
393 adns__consistency(ads
,0,cc_entex
);
397 int adns_processexceptional(adns_state ads
, int fd
, const struct timeval
*now
) {
398 adns__consistency(ads
,0,cc_entex
);
399 switch (ads
->tcpstate
) {
400 case server_disconnected
:
402 case server_connecting
:
404 if (fd
!= ads
->tcpsocket
) break;
405 adns__tcp_broken(ads
,"poll/select","exceptional condition detected");
410 adns__consistency(ads
,0,cc_entex
);
414 static void fd_event(adns_state ads
, int fd
,
415 int revent
, int pollflag
,
416 int maxfd
, const fd_set
*fds
,
417 int (*func
)(adns_state
, int fd
, const struct timeval
*now
),
418 struct timeval now
, int *r_r
) {
421 if (!(revent
& pollflag
)) return;
422 if (fds
&& !(fd
<maxfd
&& FD_ISSET(fd
,fds
))) return;
423 r
= func(ads
,fd
,&now
);
428 adns__diag(ads
,-1,0,"process fd failed after select: %s",strerror(errno
));
429 adns_globalsystemfailure(ads
);
434 void adns__fdevents(adns_state ads
,
435 const struct pollfd
*pollfds
, int npollfds
,
436 int maxfd
, const fd_set
*readfds
,
437 const fd_set
*writefds
, const fd_set
*exceptfds
,
438 struct timeval now
, int *r_r
) {
441 for (i
=0; i
<npollfds
; i
++) {
443 if (fd
>= maxfd
) maxfd
= fd
+1;
444 revents
= pollfds
[i
].revents
;
445 fd_event(ads
,fd
, revents
,POLLIN
, maxfd
,readfds
, adns_processreadable
,now
,r_r
);
446 fd_event(ads
,fd
, revents
,POLLOUT
, maxfd
,writefds
, adns_processwriteable
,now
,r_r
);
447 fd_event(ads
,fd
, revents
,POLLPRI
, maxfd
,exceptfds
, adns_processexceptional
,now
,r_r
);
451 /* Wrappers for select(2). */
453 void adns_beforeselect(adns_state ads
, int *maxfd_io
, fd_set
*readfds_io
,
454 fd_set
*writefds_io
, fd_set
*exceptfds_io
,
455 struct timeval
**tv_mod
, struct timeval
*tv_tobuf
,
456 const struct timeval
*now
) {
457 struct timeval tv_nowbuf
;
458 struct pollfd pollfds
[MAX_POLLFDS
];
459 int i
, fd
, maxfd
, npollfds
;
461 adns__consistency(ads
,0,cc_entex
);
463 if (tv_mod
&& (!*tv_mod
|| (*tv_mod
)->tv_sec
|| (*tv_mod
)->tv_usec
)) {
464 /* The caller is planning to sleep. */
465 adns__must_gettimeofday(ads
,&now
,&tv_nowbuf
);
467 adns__timeouts(ads
, 1, tv_mod
,tv_tobuf
, *now
);
470 npollfds
= adns__pollfds(ads
,pollfds
);
472 for (i
=0; i
<npollfds
; i
++) {
474 if (fd
>= maxfd
) maxfd
= fd
+1;
475 if (pollfds
[i
].events
& POLLIN
) FD_SET(fd
,readfds_io
);
476 if (pollfds
[i
].events
& POLLOUT
) FD_SET(fd
,writefds_io
);
477 if (pollfds
[i
].events
& POLLPRI
) FD_SET(fd
,exceptfds_io
);
482 adns__consistency(ads
,0,cc_entex
);
485 void adns_afterselect(adns_state ads
, int maxfd
, const fd_set
*readfds
,
486 const fd_set
*writefds
, const fd_set
*exceptfds
,
487 const struct timeval
*now
) {
488 struct timeval tv_buf
;
489 struct pollfd pollfds
[MAX_POLLFDS
];
492 adns__consistency(ads
,0,cc_entex
);
493 adns__must_gettimeofday(ads
,&now
,&tv_buf
);
495 adns_processtimeouts(ads
,now
);
497 npollfds
= adns__pollfds(ads
,pollfds
);
498 for (i
=0; i
<npollfds
; i
++) pollfds
[i
].revents
= POLLIN
|POLLOUT
|POLLPRI
;
501 maxfd
,readfds
,writefds
,exceptfds
,
504 adns__consistency(ads
,0,cc_entex
);
507 /* General helpful functions. */
509 void adns_globalsystemfailure(adns_state ads
) {
510 adns__consistency(ads
,0,cc_entex
);
512 while (ads
->timew
.head
) {
513 adns__query_fail(ads
->timew
.head
, adns_s_systemfail
);
516 switch (ads
->tcpstate
) {
517 case server_connecting
:
519 adns__tcp_closenext(ads
);
521 case server_disconnected
:
526 adns__consistency(ads
,0,cc_entex
);
529 int adns_processany(adns_state ads
) {
532 struct pollfd pollfds
[MAX_POLLFDS
];
535 adns__consistency(ads
,0,cc_entex
);
537 r
= gettimeofday(&now
,0);
538 if (!r
) adns_processtimeouts(ads
,&now
);
540 /* We just use adns__fdevents to loop over the fd's trying them.
541 * This seems more sensible than calling select, since we're most
542 * likely just to want to do a read on one or two fds anyway.
544 npollfds
= adns__pollfds(ads
,pollfds
);
545 for (i
=0; i
<npollfds
; i
++) pollfds
[i
].revents
= pollfds
[i
].events
;
551 adns__consistency(ads
,0,cc_entex
);
555 void adns__autosys(adns_state ads
, struct timeval now
) {
556 if (ads
->iflags
& adns_if_noautosys
) return;
557 adns_processany(ads
);
560 int adns__internal_check(adns_state ads
,
561 adns_query
*query_io
,
562 adns_answer
**answer
,
568 if (ads
->output
.head
) {
569 qu
= ads
->output
.head
;
570 } else if (ads
->timew
.head
) {
576 if (qu
->id
>=0) return EAGAIN
;
578 LIST_UNLINK(ads
->output
,qu
);
580 if (context_r
) *context_r
= qu
->ctx
.ext
;
586 int adns_wait(adns_state ads
,
587 adns_query
*query_io
,
588 adns_answer
**answer_r
,
591 fd_set readfds
, writefds
, exceptfds
;
592 struct timeval tvbuf
, *tvp
;
594 adns__consistency(ads
,*query_io
,cc_entex
);
596 r
= adns__internal_check(ads
,query_io
,answer_r
,context_r
);
597 if (r
!= EAGAIN
) break;
599 FD_ZERO(&readfds
); FD_ZERO(&writefds
); FD_ZERO(&exceptfds
);
600 adns_beforeselect(ads
,&maxfd
,&readfds
,&writefds
,&exceptfds
,&tvp
,&tvbuf
,0);
601 rsel
= select(maxfd
,&readfds
,&writefds
,&exceptfds
,tvp
);
603 if (errno
== EINTR
) {
604 if (ads
->iflags
& adns_if_eintr
) { r
= EINTR
; break; }
606 adns__diag(ads
,-1,0,"select failed in wait: %s",strerror(errno
));
607 adns_globalsystemfailure(ads
);
611 adns_afterselect(ads
,maxfd
,&readfds
,&writefds
,&exceptfds
,0);
614 adns__consistency(ads
,0,cc_entex
);
618 int adns_check(adns_state ads
,
619 adns_query
*query_io
,
620 adns_answer
**answer_r
,
625 adns__consistency(ads
,*query_io
,cc_entex
);
626 r
= gettimeofday(&now
,0);
627 if (!r
) adns__autosys(ads
,now
);
629 r
= adns__internal_check(ads
,query_io
,answer_r
,context_r
);
630 adns__consistency(ads
,0,cc_entex
);