e576be50 |
1 | /* |
2 | * event.c |
3 | * - event loop core |
4 | * - TCP connection management |
5 | * - user-visible check/wait and event-loop-related functions |
6 | */ |
7 | /* |
a719a4be |
8 | * This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson |
e576be50 |
9 | * |
10 | * This program is free software; you can redistribute it and/or modify |
11 | * it under the terms of the GNU General Public License as published by |
12 | * the Free Software Foundation; either version 2, or (at your option) |
13 | * any later version. |
14 | * |
15 | * This program is distributed in the hope that it will be useful, |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
18 | * GNU General Public License for more details. |
19 | * |
20 | * You should have received a copy of the GNU General Public License |
21 | * along with this program; if not, write to the Free Software Foundation, |
22 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
23 | */ |
656b2da9 |
24 | |
4353a5c4 |
25 | #include <string.h> |
26 | #include <errno.h> |
27 | #include <stdlib.h> |
28 | |
29 | #include <netdb.h> |
eec1d9c8 |
30 | #include <sys/socket.h> |
31 | #include <netinet/in.h> |
4353a5c4 |
32 | #include <arpa/inet.h> |
33 | |
34 | #include "internal.h" |
37e28fde |
35 | |
ddfda861 |
36 | /* TCP connection management */ |
656b2da9 |
37 | |
8402e34c |
38 | void adns__tcp_broken(adns_state ads, const char *what, const char *why) { |
39 | int serv; |
4353a5c4 |
40 | adns_query qu, nqu; |
8402e34c |
41 | |
42 | assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok); |
ddfda861 |
43 | serv= ads->tcpserver; |
68442019 |
44 | adns__warn(ads,serv,0,"TCP connection lost: %s: %s",what,why); |
37e28fde |
45 | close(ads->tcpsocket); |
46 | ads->tcpstate= server_disconnected; |
47 | |
4353a5c4 |
48 | for (qu= ads->timew.head; qu; qu= nqu) { |
8402e34c |
49 | nqu= qu->next; |
ddfda861 |
50 | if (qu->state == query_udp) continue; |
51 | assert(qu->state == query_tcpwait || qu->state == query_tcpsent); |
52 | qu->state= query_tcpwait; |
53 | qu->tcpfailed |= (1<<serv); |
54 | if (qu->tcpfailed == (1<<ads->nservers)-1) { |
4353a5c4 |
55 | LIST_UNLINK(ads->timew,qu); |
3955725c |
56 | adns__query_fail(qu,adns_s_allservfail); |
ddfda861 |
57 | } |
8402e34c |
58 | } |
59 | |
4353a5c4 |
60 | ads->tcprecv.used= ads->tcpsend.used= 0; |
8402e34c |
61 | ads->tcpserver= (serv+1)%ads->nservers; |
62 | } |
63 | |
ddfda861 |
64 | static void tcp_connected(adns_state ads, struct timeval now) { |
4353a5c4 |
65 | adns_query qu, nqu; |
66 | |
68442019 |
67 | adns__debug(ads,ads->tcpserver,0,"TCP connected"); |
4353a5c4 |
68 | ads->tcpstate= server_ok; |
ddfda861 |
69 | for (qu= ads->timew.head; qu; qu= nqu) { |
70 | nqu= qu->next; |
71 | if (qu->state == query_udp) continue; |
72 | assert (qu->state == query_tcpwait); |
3955725c |
73 | adns__query_tcp(qu,now); |
ddfda861 |
74 | } |
75 | } |
76 | |
77 | void adns__tcp_tryconnect(adns_state ads, struct timeval now) { |
8402e34c |
78 | int r, fd, tries; |
4353a5c4 |
79 | struct sockaddr_in addr; |
80 | struct protoent *proto; |
8402e34c |
81 | |
82 | for (tries=0; tries<ads->nservers; tries++) { |
83 | if (ads->tcpstate == server_connecting || ads->tcpstate == server_ok) return; |
84 | assert(ads->tcpstate == server_disconnected); |
4353a5c4 |
85 | assert(!ads->tcpsend.used); |
86 | assert(!ads->tcprecv.used); |
8402e34c |
87 | |
88 | proto= getprotobyname("tcp"); |
68442019 |
89 | if (!proto) { adns__diag(ads,-1,0,"unable to find protocol no. for TCP !"); return; } |
8402e34c |
90 | fd= socket(AF_INET,SOCK_STREAM,proto->p_proto); |
4353a5c4 |
91 | if (fd<0) { |
68442019 |
92 | adns__diag(ads,-1,0,"cannot create TCP socket: %s",strerror(errno)); |
4353a5c4 |
93 | return; |
94 | } |
95 | r= adns__setnonblock(ads,fd); |
96 | if (r) { |
68442019 |
97 | adns__diag(ads,-1,0,"cannot make TCP socket nonblocking: %s",strerror(r)); |
4353a5c4 |
98 | close(fd); |
99 | return; |
100 | } |
8402e34c |
101 | memset(&addr,0,sizeof(addr)); |
102 | addr.sin_family= AF_INET; |
98a3f706 |
103 | addr.sin_port= htons(DNS_PORT); |
8402e34c |
104 | addr.sin_addr= ads->servers[ads->tcpserver].addr; |
eec1d9c8 |
105 | r= connect(fd,(const struct sockaddr*)&addr,sizeof(addr)); |
8402e34c |
106 | ads->tcpsocket= fd; |
107 | ads->tcpstate= server_connecting; |
4353a5c4 |
108 | if (r==0) { tcp_connected(ads,now); continue; } |
8402e34c |
109 | if (errno == EWOULDBLOCK || errno == EINPROGRESS) return; |
ddfda861 |
110 | adns__tcp_broken(ads,"connect",strerror(errno)); |
8402e34c |
111 | } |
112 | } |
113 | |
4353a5c4 |
114 | /* `Interest' functions - find out which fd's we might be interested in, |
115 | * and when we want to be called back for a timeout. |
116 | */ |
117 | |
118 | static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf, |
119 | struct timeval maxto) { |
120 | struct timeval *rbuf; |
121 | |
122 | if (!tv_io) return; |
123 | rbuf= *tv_io; |
94436798 |
124 | if (!rbuf) { |
125 | *tvbuf= maxto; *tv_io= tvbuf; |
126 | } else { |
127 | if (timercmp(rbuf,&maxto,>)) *rbuf= maxto; |
128 | } |
ffbda80c |
129 | /*fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n", |
130 | maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec);*/ |
4353a5c4 |
131 | } |
132 | |
133 | static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf, |
134 | struct timeval now, struct timeval maxtime) { |
135 | ldiv_t dr; |
136 | |
ffbda80c |
137 | /*fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n", |
138 | now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec);*/ |
4353a5c4 |
139 | if (!tv_io) return; |
94436798 |
140 | maxtime.tv_sec -= (now.tv_sec+2); |
141 | maxtime.tv_usec -= (now.tv_usec-2000000); |
142 | dr= ldiv(maxtime.tv_usec,1000000); |
4353a5c4 |
143 | maxtime.tv_sec += dr.quot; |
94436798 |
144 | maxtime.tv_usec -= dr.quot*1000000; |
145 | if (maxtime.tv_sec<0) timerclear(&maxtime); |
4353a5c4 |
146 | inter_maxto(tv_io,tvbuf,maxtime); |
147 | } |
148 | |
149 | static void inter_addfd(int *maxfd, fd_set *fds, int fd) { |
150 | if (!maxfd || !fds) return; |
151 | if (fd>=*maxfd) *maxfd= fd+1; |
152 | FD_SET(fd,fds); |
153 | } |
154 | |
155 | static void checktimeouts(adns_state ads, struct timeval now, |
156 | struct timeval **tv_io, struct timeval *tvbuf) { |
157 | adns_query qu, nqu; |
158 | |
159 | for (qu= ads->timew.head; qu; qu= nqu) { |
160 | nqu= qu->next; |
161 | if (timercmp(&now,&qu->timeout,>)) { |
162 | LIST_UNLINK(ads->timew,qu); |
163 | if (qu->state != query_udp) { |
3955725c |
164 | adns__query_fail(qu,adns_s_timeout); |
4353a5c4 |
165 | } else { |
3955725c |
166 | adns__query_udp(qu,now); |
4353a5c4 |
167 | } |
168 | } else { |
169 | inter_maxtoabs(tv_io,tvbuf,now,qu->timeout); |
170 | } |
171 | } |
172 | } |
173 | |
174 | void adns_interest(adns_state ads, int *maxfd, |
175 | fd_set *readfds, fd_set *writefds, fd_set *exceptfds, |
176 | struct timeval **tv_io, struct timeval *tvbuf) { |
177 | struct timeval now; |
178 | struct timeval tvto_lr; |
179 | int r; |
180 | |
ffbda80c |
181 | /*fprintf(stderr,"adns_interest\n");*/ |
94436798 |
182 | |
ffbda80c |
183 | r= gettimeofday(&now,0); |
4353a5c4 |
184 | if (r) { |
68442019 |
185 | adns__warn(ads,-1,0,"gettimeofday failed - will sleep for a bit: %s", |
186 | strerror(errno)); |
4353a5c4 |
187 | timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS); |
188 | inter_maxto(tv_io, tvbuf, tvto_lr); |
189 | } else { |
190 | checktimeouts(ads,now,tv_io,tvbuf); |
191 | } |
192 | |
193 | inter_addfd(maxfd,readfds,ads->udpsocket); |
194 | |
195 | switch (ads->tcpstate) { |
196 | case server_disconnected: |
197 | break; |
198 | case server_connecting: |
199 | inter_addfd(maxfd,writefds,ads->tcpsocket); |
200 | break; |
201 | case server_ok: |
202 | inter_addfd(maxfd,readfds,ads->tcpsocket); |
203 | inter_addfd(maxfd,exceptfds,ads->tcpsocket); |
204 | if (ads->tcpsend.used) inter_addfd(maxfd,writefds,ads->tcpsocket); |
e062dcae |
205 | break; |
4353a5c4 |
206 | default: |
207 | abort(); |
208 | } |
209 | } |
210 | |
ddfda861 |
211 | /* Callback procedures - these do the real work of reception and timeout, etc. */ |
212 | |
213 | static int callb_checkfd(int maxfd, const fd_set *fds, int fd) { |
214 | return maxfd<0 || !fds ? 1 : |
215 | fd<maxfd && FD_ISSET(fd,fds); |
216 | } |
217 | |
218 | static int internal_callback(adns_state ads, int maxfd, |
219 | const fd_set *readfds, const fd_set *writefds, |
4353a5c4 |
220 | const fd_set *exceptfds, |
221 | struct timeval now) { |
222 | int skip, want, dgramlen, count, udpaddrlen, r, serv; |
98a3f706 |
223 | byte udpbuf[DNS_MAXUDP]; |
37e28fde |
224 | struct sockaddr_in udpaddr; |
656b2da9 |
225 | |
226 | count= 0; |
ddfda861 |
227 | |
228 | switch (ads->tcpstate) { |
229 | case server_disconnected: |
230 | break; |
231 | case server_connecting: |
656b2da9 |
232 | if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) { |
233 | count++; |
234 | assert(ads->tcprecv.used==0); |
e062dcae |
235 | if (!adns__vbuf_ensure(&ads->tcprecv,1)) return -1; |
656b2da9 |
236 | if (ads->tcprecv.buf) { |
237 | r= read(ads->tcpsocket,&ads->tcprecv.buf,1); |
238 | if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) { |
4353a5c4 |
239 | tcp_connected(ads,now); |
656b2da9 |
240 | } else if (r>0) { |
4353a5c4 |
241 | adns__tcp_broken(ads,"connect/read","sent data before first request"); |
656b2da9 |
242 | } else if (errno!=EINTR) { |
4353a5c4 |
243 | adns__tcp_broken(ads,"connect/read",strerror(errno)); |
656b2da9 |
244 | } |
245 | } |
246 | } |
ddfda861 |
247 | break; |
248 | case server_ok: |
249 | count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) + |
250 | callb_checkfd(maxfd,exceptfds,ads->tcpsocket) + |
251 | (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)); |
252 | if (callb_checkfd(maxfd,readfds,ads->tcpsocket)) { |
656b2da9 |
253 | skip= 0; |
254 | for (;;) { |
255 | if (ads->tcprecv.used<skip+2) { |
256 | want= 2; |
257 | } else { |
258 | dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1]; |
259 | if (ads->tcprecv.used<skip+2+dgramlen) { |
260 | want= 2+dgramlen; |
261 | } else { |
98a3f706 |
262 | adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,now); |
656b2da9 |
263 | skip+= 2+dgramlen; continue; |
264 | } |
265 | } |
37e28fde |
266 | ads->tcprecv.used -= skip; |
656b2da9 |
267 | memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used); |
e062dcae |
268 | skip= 0; |
269 | if (!adns__vbuf_ensure(&ads->tcprecv,want)) return -1; |
270 | assert(ads->tcprecv.used <= ads->tcprecv.avail); |
271 | if (ads->tcprecv.used == ads->tcprecv.avail) continue; |
656b2da9 |
272 | r= read(ads->tcpsocket, |
273 | ads->tcprecv.buf+ads->tcprecv.used, |
274 | ads->tcprecv.avail-ads->tcprecv.used); |
275 | if (r>0) { |
276 | ads->tcprecv.used+= r; |
277 | } else { |
278 | if (r<0) { |
279 | if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break; |
280 | if (errno==EINTR) continue; |
281 | } |
4353a5c4 |
282 | adns__tcp_broken(ads,"read",r?strerror(errno):"closed"); |
656b2da9 |
283 | break; |
284 | } |
285 | } |
286 | } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) { |
4353a5c4 |
287 | adns__tcp_broken(ads,"select","exceptional condition detected"); |
656b2da9 |
288 | } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) { |
ac868fa8 |
289 | adns__sigpipe_protect(ads); |
656b2da9 |
290 | r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used); |
ac868fa8 |
291 | adns__sigpipe_unprotect(ads); |
656b2da9 |
292 | if (r<0) { |
293 | if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) { |
4353a5c4 |
294 | adns__tcp_broken(ads,"write",strerror(errno)); |
656b2da9 |
295 | } |
296 | } else if (r>0) { |
297 | ads->tcpsend.used -= r; |
298 | memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used); |
299 | } |
300 | } |
e062dcae |
301 | break; |
ddfda861 |
302 | default: |
303 | abort(); |
656b2da9 |
304 | } |
305 | |
37e28fde |
306 | if (callb_checkfd(maxfd,readfds,ads->udpsocket)) { |
307 | count++; |
308 | for (;;) { |
309 | udpaddrlen= sizeof(udpaddr); |
eec1d9c8 |
310 | r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0, |
311 | (struct sockaddr*)&udpaddr,&udpaddrlen); |
37e28fde |
312 | if (r<0) { |
313 | if (!(errno == EAGAIN || errno == EWOULDBLOCK || |
314 | errno == EINTR || errno == ENOMEM || errno == ENOBUFS)) |
68442019 |
315 | adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno)); |
37e28fde |
316 | break; |
317 | } |
318 | if (udpaddrlen != sizeof(udpaddr)) { |
68442019 |
319 | adns__diag(ads,-1,0,"datagram received with wrong address length %d" |
320 | " (expected %d)", udpaddrlen,sizeof(udpaddr)); |
37e28fde |
321 | continue; |
322 | } |
323 | if (udpaddr.sin_family != AF_INET) { |
68442019 |
324 | adns__diag(ads,-1,0,"datagram received with wrong protocol family" |
4353a5c4 |
325 | " %u (expected %u)",udpaddr.sin_family,AF_INET); |
37e28fde |
326 | continue; |
327 | } |
98a3f706 |
328 | if (ntohs(udpaddr.sin_port) != DNS_PORT) { |
68442019 |
329 | adns__diag(ads,-1,0,"datagram received from wrong port %u (expected %u)", |
98a3f706 |
330 | ntohs(udpaddr.sin_port),DNS_PORT); |
37e28fde |
331 | continue; |
332 | } |
333 | for (serv= 0; |
334 | serv < ads->nservers && |
335 | ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr; |
336 | serv++); |
337 | if (serv >= ads->nservers) { |
68442019 |
338 | adns__warn(ads,-1,0,"datagram received from unknown nameserver %s", |
4353a5c4 |
339 | inet_ntoa(udpaddr.sin_addr)); |
37e28fde |
340 | continue; |
341 | } |
98a3f706 |
342 | adns__procdgram(ads,udpbuf,r,serv,now); |
656b2da9 |
343 | } |
37e28fde |
344 | } |
4353a5c4 |
345 | return count; |
656b2da9 |
346 | } |
656b2da9 |
347 | |
ddfda861 |
348 | int adns_callback(adns_state ads, int maxfd, |
349 | const fd_set *readfds, const fd_set *writefds, |
350 | const fd_set *exceptfds) { |
351 | struct timeval now; |
656b2da9 |
352 | int r; |
37e28fde |
353 | |
4353a5c4 |
354 | r= gettimeofday(&now,0); if (r) return -1; |
355 | checktimeouts(ads,now,0,0); |
356 | return internal_callback(ads,maxfd,readfds,writefds,exceptfds,now); |
656b2da9 |
357 | } |
358 | |
ddfda861 |
359 | /* User-visible functions and their implementation. */ |
360 | |
4353a5c4 |
361 | void adns__autosys(adns_state ads, struct timeval now) { |
ddfda861 |
362 | if (ads->iflags & adns_if_noautosys) return; |
363 | adns_callback(ads,-1,0,0,0); |
364 | } |
365 | |
656b2da9 |
366 | static int internal_check(adns_state ads, |
367 | adns_query *query_io, |
368 | adns_answer **answer, |
369 | void **context_r) { |
370 | adns_query qu; |
371 | |
372 | qu= *query_io; |
373 | if (!qu) { |
374 | if (!ads->output.head) return EWOULDBLOCK; |
375 | qu= ads->output.head; |
376 | } else { |
377 | if (qu->id>=0) return EWOULDBLOCK; |
378 | } |
379 | LIST_UNLINK(ads->output,qu); |
8e5b0abb |
380 | *answer= qu->answer; |
a6536d8b |
381 | if (context_r) *context_r= qu->ctx.ext; |
656b2da9 |
382 | free(qu); |
383 | return 0; |
384 | } |
385 | |
386 | int adns_wait(adns_state ads, |
387 | adns_query *query_io, |
388 | adns_answer **answer_r, |
389 | void **context_r) { |
390 | int r, maxfd, rsel, rcb; |
391 | fd_set readfds, writefds, exceptfds; |
392 | struct timeval tvbuf, *tvp; |
393 | |
394 | for (;;) { |
395 | r= internal_check(ads,query_io,answer_r,context_r); |
94436798 |
396 | if (r != EWOULDBLOCK) return r; |
656b2da9 |
397 | maxfd= 0; tvp= 0; |
37e28fde |
398 | FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds); |
656b2da9 |
399 | adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf); |
400 | rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp); |
88372443 |
401 | if (rsel==-1) { |
402 | if (errno == EINTR && !(ads->iflags & adns_if_eintr)) continue; |
403 | return errno; |
404 | } |
4353a5c4 |
405 | rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds); |
656b2da9 |
406 | assert(rcb==rsel); |
407 | } |
408 | } |
409 | |
410 | int adns_check(adns_state ads, |
411 | adns_query *query_io, |
412 | adns_answer **answer_r, |
413 | void **context_r) { |
4353a5c4 |
414 | struct timeval now; |
415 | int r; |
416 | |
417 | r= gettimeofday(&now,0); if (r) return errno; |
418 | adns__autosys(ads,now); |
656b2da9 |
419 | return internal_check(ads,query_io,answer_r,context_r); |
420 | } |