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 | /* |
8 | * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson |
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> |
30 | #include <arpa/inet.h> |
31 | |
32 | #include "internal.h" |
37e28fde |
33 | |
ddfda861 |
34 | /* TCP connection management */ |
656b2da9 |
35 | |
8402e34c |
36 | void adns__tcp_broken(adns_state ads, const char *what, const char *why) { |
37 | int serv; |
4353a5c4 |
38 | adns_query qu, nqu; |
8402e34c |
39 | |
40 | assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok); |
ddfda861 |
41 | serv= ads->tcpserver; |
68442019 |
42 | adns__warn(ads,serv,0,"TCP connection lost: %s: %s",what,why); |
37e28fde |
43 | close(ads->tcpsocket); |
44 | ads->tcpstate= server_disconnected; |
45 | |
4353a5c4 |
46 | for (qu= ads->timew.head; qu; qu= nqu) { |
8402e34c |
47 | nqu= qu->next; |
ddfda861 |
48 | if (qu->state == query_udp) continue; |
49 | assert(qu->state == query_tcpwait || qu->state == query_tcpsent); |
50 | qu->state= query_tcpwait; |
51 | qu->tcpfailed |= (1<<serv); |
52 | if (qu->tcpfailed == (1<<ads->nservers)-1) { |
4353a5c4 |
53 | LIST_UNLINK(ads->timew,qu); |
3955725c |
54 | adns__query_fail(qu,adns_s_allservfail); |
ddfda861 |
55 | } |
8402e34c |
56 | } |
57 | |
4353a5c4 |
58 | ads->tcprecv.used= ads->tcpsend.used= 0; |
8402e34c |
59 | ads->tcpserver= (serv+1)%ads->nservers; |
60 | } |
61 | |
ddfda861 |
62 | static void tcp_connected(adns_state ads, struct timeval now) { |
4353a5c4 |
63 | adns_query qu, nqu; |
64 | |
68442019 |
65 | adns__debug(ads,ads->tcpserver,0,"TCP connected"); |
4353a5c4 |
66 | ads->tcpstate= server_ok; |
ddfda861 |
67 | for (qu= ads->timew.head; qu; qu= nqu) { |
68 | nqu= qu->next; |
69 | if (qu->state == query_udp) continue; |
70 | assert (qu->state == query_tcpwait); |
3955725c |
71 | adns__query_tcp(qu,now); |
ddfda861 |
72 | } |
73 | } |
74 | |
75 | void adns__tcp_tryconnect(adns_state ads, struct timeval now) { |
8402e34c |
76 | int r, fd, tries; |
4353a5c4 |
77 | struct sockaddr_in addr; |
78 | struct protoent *proto; |
ddfda861 |
79 | /* fixme: single TCP timeout, not once per server */ |
8402e34c |
80 | |
81 | for (tries=0; tries<ads->nservers; tries++) { |
82 | if (ads->tcpstate == server_connecting || ads->tcpstate == server_ok) return; |
83 | assert(ads->tcpstate == server_disconnected); |
4353a5c4 |
84 | assert(!ads->tcpsend.used); |
85 | assert(!ads->tcprecv.used); |
8402e34c |
86 | |
87 | proto= getprotobyname("tcp"); |
68442019 |
88 | if (!proto) { adns__diag(ads,-1,0,"unable to find protocol no. for TCP !"); return; } |
8402e34c |
89 | fd= socket(AF_INET,SOCK_STREAM,proto->p_proto); |
4353a5c4 |
90 | if (fd<0) { |
68442019 |
91 | adns__diag(ads,-1,0,"cannot create TCP socket: %s",strerror(errno)); |
4353a5c4 |
92 | return; |
93 | } |
94 | r= adns__setnonblock(ads,fd); |
95 | if (r) { |
68442019 |
96 | adns__diag(ads,-1,0,"cannot make TCP socket nonblocking: %s",strerror(r)); |
4353a5c4 |
97 | close(fd); |
98 | return; |
99 | } |
8402e34c |
100 | memset(&addr,0,sizeof(addr)); |
101 | addr.sin_family= AF_INET; |
98a3f706 |
102 | addr.sin_port= htons(DNS_PORT); |
8402e34c |
103 | addr.sin_addr= ads->servers[ads->tcpserver].addr; |
104 | r= connect(fd,&addr,sizeof(addr)); |
105 | ads->tcpsocket= fd; |
106 | ads->tcpstate= server_connecting; |
4353a5c4 |
107 | if (r==0) { tcp_connected(ads,now); continue; } |
8402e34c |
108 | if (errno == EWOULDBLOCK || errno == EINPROGRESS) return; |
ddfda861 |
109 | adns__tcp_broken(ads,"connect",strerror(errno)); |
8402e34c |
110 | } |
111 | } |
112 | |
4353a5c4 |
113 | /* `Interest' functions - find out which fd's we might be interested in, |
114 | * and when we want to be called back for a timeout. |
115 | */ |
116 | |
117 | static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf, |
118 | struct timeval maxto) { |
119 | struct timeval *rbuf; |
120 | |
121 | if (!tv_io) return; |
122 | rbuf= *tv_io; |
94436798 |
123 | if (!rbuf) { |
124 | *tvbuf= maxto; *tv_io= tvbuf; |
125 | } else { |
126 | if (timercmp(rbuf,&maxto,>)) *rbuf= maxto; |
127 | } |
ffbda80c |
128 | /*fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n", |
129 | maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec);*/ |
4353a5c4 |
130 | } |
131 | |
132 | static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf, |
133 | struct timeval now, struct timeval maxtime) { |
134 | ldiv_t dr; |
135 | |
ffbda80c |
136 | /*fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n", |
137 | now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec);*/ |
4353a5c4 |
138 | if (!tv_io) return; |
94436798 |
139 | maxtime.tv_sec -= (now.tv_sec+2); |
140 | maxtime.tv_usec -= (now.tv_usec-2000000); |
141 | dr= ldiv(maxtime.tv_usec,1000000); |
4353a5c4 |
142 | maxtime.tv_sec += dr.quot; |
94436798 |
143 | maxtime.tv_usec -= dr.quot*1000000; |
144 | if (maxtime.tv_sec<0) timerclear(&maxtime); |
4353a5c4 |
145 | inter_maxto(tv_io,tvbuf,maxtime); |
146 | } |
147 | |
148 | static void inter_addfd(int *maxfd, fd_set *fds, int fd) { |
149 | if (!maxfd || !fds) return; |
150 | if (fd>=*maxfd) *maxfd= fd+1; |
151 | FD_SET(fd,fds); |
152 | } |
153 | |
154 | static void checktimeouts(adns_state ads, struct timeval now, |
155 | struct timeval **tv_io, struct timeval *tvbuf) { |
156 | adns_query qu, nqu; |
157 | |
158 | for (qu= ads->timew.head; qu; qu= nqu) { |
159 | nqu= qu->next; |
160 | if (timercmp(&now,&qu->timeout,>)) { |
161 | LIST_UNLINK(ads->timew,qu); |
162 | if (qu->state != query_udp) { |
3955725c |
163 | adns__query_fail(qu,adns_s_timeout); |
4353a5c4 |
164 | } else { |
3955725c |
165 | adns__query_udp(qu,now); |
4353a5c4 |
166 | } |
167 | } else { |
168 | inter_maxtoabs(tv_io,tvbuf,now,qu->timeout); |
169 | } |
170 | } |
171 | } |
172 | |
173 | void adns_interest(adns_state ads, int *maxfd, |
174 | fd_set *readfds, fd_set *writefds, fd_set *exceptfds, |
175 | struct timeval **tv_io, struct timeval *tvbuf) { |
176 | struct timeval now; |
177 | struct timeval tvto_lr; |
178 | int r; |
179 | |
ffbda80c |
180 | /*fprintf(stderr,"adns_interest\n");*/ |
94436798 |
181 | |
ffbda80c |
182 | r= gettimeofday(&now,0); |
4353a5c4 |
183 | if (r) { |
68442019 |
184 | adns__warn(ads,-1,0,"gettimeofday failed - will sleep for a bit: %s", |
185 | strerror(errno)); |
4353a5c4 |
186 | timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS); |
187 | inter_maxto(tv_io, tvbuf, tvto_lr); |
188 | } else { |
189 | checktimeouts(ads,now,tv_io,tvbuf); |
190 | } |
191 | |
192 | inter_addfd(maxfd,readfds,ads->udpsocket); |
193 | |
194 | switch (ads->tcpstate) { |
195 | case server_disconnected: |
196 | break; |
197 | case server_connecting: |
198 | inter_addfd(maxfd,writefds,ads->tcpsocket); |
199 | break; |
200 | case server_ok: |
201 | inter_addfd(maxfd,readfds,ads->tcpsocket); |
202 | inter_addfd(maxfd,exceptfds,ads->tcpsocket); |
203 | if (ads->tcpsend.used) inter_addfd(maxfd,writefds,ads->tcpsocket); |
204 | default: |
205 | abort(); |
206 | } |
207 | } |
208 | |
ddfda861 |
209 | /* Callback procedures - these do the real work of reception and timeout, etc. */ |
210 | |
211 | static int callb_checkfd(int maxfd, const fd_set *fds, int fd) { |
212 | return maxfd<0 || !fds ? 1 : |
213 | fd<maxfd && FD_ISSET(fd,fds); |
214 | } |
215 | |
216 | static int internal_callback(adns_state ads, int maxfd, |
217 | const fd_set *readfds, const fd_set *writefds, |
4353a5c4 |
218 | const fd_set *exceptfds, |
219 | struct timeval now) { |
220 | int skip, want, dgramlen, count, udpaddrlen, r, serv; |
98a3f706 |
221 | byte udpbuf[DNS_MAXUDP]; |
37e28fde |
222 | struct sockaddr_in udpaddr; |
656b2da9 |
223 | |
224 | count= 0; |
ddfda861 |
225 | |
226 | switch (ads->tcpstate) { |
227 | case server_disconnected: |
228 | break; |
229 | case server_connecting: |
656b2da9 |
230 | if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) { |
231 | count++; |
232 | assert(ads->tcprecv.used==0); |
4353a5c4 |
233 | adns__vbuf_ensure(&ads->tcprecv,1); |
656b2da9 |
234 | if (ads->tcprecv.buf) { |
235 | r= read(ads->tcpsocket,&ads->tcprecv.buf,1); |
236 | if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) { |
4353a5c4 |
237 | tcp_connected(ads,now); |
656b2da9 |
238 | } else if (r>0) { |
4353a5c4 |
239 | adns__tcp_broken(ads,"connect/read","sent data before first request"); |
656b2da9 |
240 | } else if (errno!=EINTR) { |
4353a5c4 |
241 | adns__tcp_broken(ads,"connect/read",strerror(errno)); |
656b2da9 |
242 | } |
243 | } |
244 | } |
ddfda861 |
245 | break; |
246 | case server_ok: |
247 | count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) + |
248 | callb_checkfd(maxfd,exceptfds,ads->tcpsocket) + |
249 | (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)); |
250 | if (callb_checkfd(maxfd,readfds,ads->tcpsocket)) { |
656b2da9 |
251 | skip= 0; |
252 | for (;;) { |
253 | if (ads->tcprecv.used<skip+2) { |
254 | want= 2; |
255 | } else { |
256 | dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1]; |
257 | if (ads->tcprecv.used<skip+2+dgramlen) { |
258 | want= 2+dgramlen; |
259 | } else { |
98a3f706 |
260 | adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,now); |
656b2da9 |
261 | skip+= 2+dgramlen; continue; |
262 | } |
263 | } |
37e28fde |
264 | ads->tcprecv.used -= skip; |
656b2da9 |
265 | memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used); |
4353a5c4 |
266 | adns__vbuf_ensure(&ads->tcprecv,want); |
656b2da9 |
267 | if (ads->tcprecv.used >= ads->tcprecv.avail) break; |
268 | r= read(ads->tcpsocket, |
269 | ads->tcprecv.buf+ads->tcprecv.used, |
270 | ads->tcprecv.avail-ads->tcprecv.used); |
271 | if (r>0) { |
272 | ads->tcprecv.used+= r; |
273 | } else { |
274 | if (r<0) { |
275 | if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break; |
276 | if (errno==EINTR) continue; |
277 | } |
4353a5c4 |
278 | adns__tcp_broken(ads,"read",r?strerror(errno):"closed"); |
656b2da9 |
279 | break; |
280 | } |
281 | } |
282 | } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) { |
4353a5c4 |
283 | adns__tcp_broken(ads,"select","exceptional condition detected"); |
656b2da9 |
284 | } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) { |
285 | r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used); |
286 | if (r<0) { |
287 | if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) { |
4353a5c4 |
288 | adns__tcp_broken(ads,"write",strerror(errno)); |
656b2da9 |
289 | } |
290 | } else if (r>0) { |
291 | ads->tcpsend.used -= r; |
292 | memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used); |
293 | } |
294 | } |
ddfda861 |
295 | default: |
296 | abort(); |
656b2da9 |
297 | } |
298 | |
37e28fde |
299 | if (callb_checkfd(maxfd,readfds,ads->udpsocket)) { |
300 | count++; |
301 | for (;;) { |
302 | udpaddrlen= sizeof(udpaddr); |
303 | r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,&udpaddr,&udpaddrlen); |
304 | if (r<0) { |
305 | if (!(errno == EAGAIN || errno == EWOULDBLOCK || |
306 | errno == EINTR || errno == ENOMEM || errno == ENOBUFS)) |
68442019 |
307 | adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno)); |
37e28fde |
308 | break; |
309 | } |
310 | if (udpaddrlen != sizeof(udpaddr)) { |
68442019 |
311 | adns__diag(ads,-1,0,"datagram received with wrong address length %d" |
312 | " (expected %d)", udpaddrlen,sizeof(udpaddr)); |
37e28fde |
313 | continue; |
314 | } |
315 | if (udpaddr.sin_family != AF_INET) { |
68442019 |
316 | adns__diag(ads,-1,0,"datagram received with wrong protocol family" |
4353a5c4 |
317 | " %u (expected %u)",udpaddr.sin_family,AF_INET); |
37e28fde |
318 | continue; |
319 | } |
98a3f706 |
320 | if (ntohs(udpaddr.sin_port) != DNS_PORT) { |
68442019 |
321 | adns__diag(ads,-1,0,"datagram received from wrong port %u (expected %u)", |
98a3f706 |
322 | ntohs(udpaddr.sin_port),DNS_PORT); |
37e28fde |
323 | continue; |
324 | } |
325 | for (serv= 0; |
326 | serv < ads->nservers && |
327 | ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr; |
328 | serv++); |
329 | if (serv >= ads->nservers) { |
68442019 |
330 | adns__warn(ads,-1,0,"datagram received from unknown nameserver %s", |
4353a5c4 |
331 | inet_ntoa(udpaddr.sin_addr)); |
37e28fde |
332 | continue; |
333 | } |
98a3f706 |
334 | adns__procdgram(ads,udpbuf,r,serv,now); |
656b2da9 |
335 | } |
37e28fde |
336 | } |
4353a5c4 |
337 | return count; |
656b2da9 |
338 | } |
656b2da9 |
339 | |
ddfda861 |
340 | int adns_callback(adns_state ads, int maxfd, |
341 | const fd_set *readfds, const fd_set *writefds, |
342 | const fd_set *exceptfds) { |
343 | struct timeval now; |
656b2da9 |
344 | int r; |
37e28fde |
345 | |
4353a5c4 |
346 | r= gettimeofday(&now,0); if (r) return -1; |
347 | checktimeouts(ads,now,0,0); |
348 | return internal_callback(ads,maxfd,readfds,writefds,exceptfds,now); |
656b2da9 |
349 | } |
350 | |
ddfda861 |
351 | /* User-visible functions and their implementation. */ |
352 | |
4353a5c4 |
353 | void adns__autosys(adns_state ads, struct timeval now) { |
ddfda861 |
354 | if (ads->iflags & adns_if_noautosys) return; |
355 | adns_callback(ads,-1,0,0,0); |
356 | } |
357 | |
656b2da9 |
358 | static int internal_check(adns_state ads, |
359 | adns_query *query_io, |
360 | adns_answer **answer, |
361 | void **context_r) { |
362 | adns_query qu; |
363 | |
364 | qu= *query_io; |
365 | if (!qu) { |
366 | if (!ads->output.head) return EWOULDBLOCK; |
367 | qu= ads->output.head; |
368 | } else { |
369 | if (qu->id>=0) return EWOULDBLOCK; |
370 | } |
371 | LIST_UNLINK(ads->output,qu); |
8e5b0abb |
372 | *answer= qu->answer; |
4353a5c4 |
373 | if (context_r) *context_r= qu->context.ext; |
656b2da9 |
374 | free(qu); |
375 | return 0; |
376 | } |
377 | |
378 | int adns_wait(adns_state ads, |
379 | adns_query *query_io, |
380 | adns_answer **answer_r, |
381 | void **context_r) { |
382 | int r, maxfd, rsel, rcb; |
383 | fd_set readfds, writefds, exceptfds; |
384 | struct timeval tvbuf, *tvp; |
385 | |
386 | for (;;) { |
387 | r= internal_check(ads,query_io,answer_r,context_r); |
94436798 |
388 | if (r != EWOULDBLOCK) return r; |
656b2da9 |
389 | maxfd= 0; tvp= 0; |
37e28fde |
390 | FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds); |
656b2da9 |
391 | adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf); |
392 | rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp); |
393 | if (rsel==-1) return r; |
4353a5c4 |
394 | rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds); |
656b2da9 |
395 | assert(rcb==rsel); |
396 | } |
397 | } |
398 | |
399 | int adns_check(adns_state ads, |
400 | adns_query *query_io, |
401 | adns_answer **answer_r, |
402 | void **context_r) { |
4353a5c4 |
403 | struct timeval now; |
404 | int r; |
405 | |
406 | r= gettimeofday(&now,0); if (r) return errno; |
407 | adns__autosys(ads,now); |
656b2da9 |
408 | return internal_check(ads,query_io,answer_r,context_r); |
409 | } |