12 /* TCP connection management */
14 void adns__tcp_broken(adns_state ads, const char *what, const char *why) {
18 assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok);
20 adns__warn(ads,serv,0,"TCP connection lost: %s: %s",what,why);
21 close(ads->tcpsocket);
22 ads->tcpstate= server_disconnected;
24 for (qu= ads->timew.head; qu; qu= nqu) {
26 if (qu->state == query_udp) continue;
27 assert(qu->state == query_tcpwait || qu->state == query_tcpsent);
28 qu->state= query_tcpwait;
29 qu->tcpfailed |= (1<<serv);
30 if (qu->tcpfailed == (1<<ads->nservers)-1) {
31 LIST_UNLINK(ads->timew,qu);
32 adns__query_fail(ads,qu,adns_s_allservfail);
36 ads->tcprecv.used= ads->tcpsend.used= 0;
37 ads->tcpserver= (serv+1)%ads->nservers;
40 static void tcp_connected(adns_state ads, struct timeval now) {
43 adns__debug(ads,ads->tcpserver,0,"TCP connected");
44 ads->tcpstate= server_ok;
45 for (qu= ads->timew.head; qu; qu= nqu) {
47 if (qu->state == query_udp) continue;
48 assert (qu->state == query_tcpwait);
49 adns__query_tcp(ads,qu,now);
53 void adns__tcp_tryconnect(adns_state ads, struct timeval now) {
55 struct sockaddr_in addr;
56 struct protoent *proto;
57 /* fixme: single TCP timeout, not once per server */
59 for (tries=0; tries<ads->nservers; tries++) {
60 if (ads->tcpstate == server_connecting || ads->tcpstate == server_ok) return;
61 assert(ads->tcpstate == server_disconnected);
62 assert(!ads->tcpsend.used);
63 assert(!ads->tcprecv.used);
65 proto= getprotobyname("tcp");
66 if (!proto) { adns__diag(ads,-1,0,"unable to find protocol no. for TCP !"); return; }
67 fd= socket(AF_INET,SOCK_STREAM,proto->p_proto);
69 adns__diag(ads,-1,0,"cannot create TCP socket: %s",strerror(errno));
72 r= adns__setnonblock(ads,fd);
74 adns__diag(ads,-1,0,"cannot make TCP socket nonblocking: %s",strerror(r));
78 memset(&addr,0,sizeof(addr));
79 addr.sin_family= AF_INET;
80 addr.sin_port= htons(DNS_PORT);
81 addr.sin_addr= ads->servers[ads->tcpserver].addr;
82 r= connect(fd,&addr,sizeof(addr));
84 ads->tcpstate= server_connecting;
85 if (r==0) { tcp_connected(ads,now); continue; }
86 if (errno == EWOULDBLOCK || errno == EINPROGRESS) return;
87 adns__tcp_broken(ads,"connect",strerror(errno));
91 /* `Interest' functions - find out which fd's we might be interested in,
92 * and when we want to be called back for a timeout.
95 static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
96 struct timeval maxto) {
102 *tvbuf= maxto; *tv_io= tvbuf;
104 if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
106 fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n",
107 maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec);
110 static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
111 struct timeval now, struct timeval maxtime) {
114 fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n",
115 now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec);
117 maxtime.tv_sec -= (now.tv_sec+2);
118 maxtime.tv_usec -= (now.tv_usec-2000000);
119 dr= ldiv(maxtime.tv_usec,1000000);
120 maxtime.tv_sec += dr.quot;
121 maxtime.tv_usec -= dr.quot*1000000;
122 if (maxtime.tv_sec<0) timerclear(&maxtime);
123 inter_maxto(tv_io,tvbuf,maxtime);
126 static void inter_addfd(int *maxfd, fd_set *fds, int fd) {
127 if (!maxfd || !fds) return;
128 if (fd>=*maxfd) *maxfd= fd+1;
132 static void checktimeouts(adns_state ads, struct timeval now,
133 struct timeval **tv_io, struct timeval *tvbuf) {
136 for (qu= ads->timew.head; qu; qu= nqu) {
138 if (timercmp(&now,&qu->timeout,>)) {
139 LIST_UNLINK(ads->timew,qu);
140 if (qu->state != query_udp) {
141 adns__query_fail(ads,qu,adns_s_timeout);
143 adns__query_udp(ads,qu,now);
146 inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
151 void adns_interest(adns_state ads, int *maxfd,
152 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
153 struct timeval **tv_io, struct timeval *tvbuf) {
155 struct timeval tvto_lr;
158 fprintf(stderr,"adns_interest\n");
160 r= gettimeofday(&now,0);
162 adns__warn(ads,-1,0,"gettimeofday failed - will sleep for a bit: %s",
164 timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
165 inter_maxto(tv_io, tvbuf, tvto_lr);
167 checktimeouts(ads,now,tv_io,tvbuf);
170 inter_addfd(maxfd,readfds,ads->udpsocket);
172 switch (ads->tcpstate) {
173 case server_disconnected:
175 case server_connecting:
176 inter_addfd(maxfd,writefds,ads->tcpsocket);
179 inter_addfd(maxfd,readfds,ads->tcpsocket);
180 inter_addfd(maxfd,exceptfds,ads->tcpsocket);
181 if (ads->tcpsend.used) inter_addfd(maxfd,writefds,ads->tcpsocket);
187 /* Callback procedures - these do the real work of reception and timeout, etc. */
189 static int callb_checkfd(int maxfd, const fd_set *fds, int fd) {
190 return maxfd<0 || !fds ? 1 :
191 fd<maxfd && FD_ISSET(fd,fds);
194 static int internal_callback(adns_state ads, int maxfd,
195 const fd_set *readfds, const fd_set *writefds,
196 const fd_set *exceptfds,
197 struct timeval now) {
198 int skip, want, dgramlen, count, udpaddrlen, r, serv;
199 byte udpbuf[DNS_MAXUDP];
200 struct sockaddr_in udpaddr;
204 switch (ads->tcpstate) {
205 case server_disconnected:
207 case server_connecting:
208 if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
210 assert(ads->tcprecv.used==0);
211 adns__vbuf_ensure(&ads->tcprecv,1);
212 if (ads->tcprecv.buf) {
213 r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
214 if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
215 tcp_connected(ads,now);
217 adns__tcp_broken(ads,"connect/read","sent data before first request");
218 } else if (errno!=EINTR) {
219 adns__tcp_broken(ads,"connect/read",strerror(errno));
225 count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
226 callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
227 (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
228 if (callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
231 if (ads->tcprecv.used<skip+2) {
234 dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1];
235 if (ads->tcprecv.used<skip+2+dgramlen) {
238 adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,now);
239 skip+= 2+dgramlen; continue;
242 ads->tcprecv.used -= skip;
243 memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
244 adns__vbuf_ensure(&ads->tcprecv,want);
245 if (ads->tcprecv.used >= ads->tcprecv.avail) break;
246 r= read(ads->tcpsocket,
247 ads->tcprecv.buf+ads->tcprecv.used,
248 ads->tcprecv.avail-ads->tcprecv.used);
250 ads->tcprecv.used+= r;
253 if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break;
254 if (errno==EINTR) continue;
256 adns__tcp_broken(ads,"read",r?strerror(errno):"closed");
260 } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) {
261 adns__tcp_broken(ads,"select","exceptional condition detected");
262 } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
263 r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
265 if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) {
266 adns__tcp_broken(ads,"write",strerror(errno));
269 ads->tcpsend.used -= r;
270 memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
277 if (callb_checkfd(maxfd,readfds,ads->udpsocket)) {
280 udpaddrlen= sizeof(udpaddr);
281 r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,&udpaddr,&udpaddrlen);
283 if (!(errno == EAGAIN || errno == EWOULDBLOCK ||
284 errno == EINTR || errno == ENOMEM || errno == ENOBUFS))
285 adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno));
288 if (udpaddrlen != sizeof(udpaddr)) {
289 adns__diag(ads,-1,0,"datagram received with wrong address length %d"
290 " (expected %d)", udpaddrlen,sizeof(udpaddr));
293 if (udpaddr.sin_family != AF_INET) {
294 adns__diag(ads,-1,0,"datagram received with wrong protocol family"
295 " %u (expected %u)",udpaddr.sin_family,AF_INET);
298 if (ntohs(udpaddr.sin_port) != DNS_PORT) {
299 adns__diag(ads,-1,0,"datagram received from wrong port %u (expected %u)",
300 ntohs(udpaddr.sin_port),DNS_PORT);
304 serv < ads->nservers &&
305 ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr;
307 if (serv >= ads->nservers) {
308 adns__warn(ads,-1,0,"datagram received from unknown nameserver %s",
309 inet_ntoa(udpaddr.sin_addr));
312 adns__procdgram(ads,udpbuf,r,serv,now);
318 int adns_callback(adns_state ads, int maxfd,
319 const fd_set *readfds, const fd_set *writefds,
320 const fd_set *exceptfds) {
324 r= gettimeofday(&now,0); if (r) return -1;
325 checktimeouts(ads,now,0,0);
326 return internal_callback(ads,maxfd,readfds,writefds,exceptfds,now);
329 /* User-visible functions and their implementation. */
331 void adns__autosys(adns_state ads, struct timeval now) {
332 if (ads->iflags & adns_if_noautosys) return;
333 adns_callback(ads,-1,0,0,0);
336 static int internal_check(adns_state ads,
337 adns_query *query_io,
338 adns_answer **answer,
344 if (!ads->output.head) return EWOULDBLOCK;
345 qu= ads->output.head;
347 if (qu->id>=0) return EWOULDBLOCK;
349 LIST_UNLINK(ads->output,qu);
351 if (context_r) *context_r= qu->context.ext;
356 int adns_wait(adns_state ads,
357 adns_query *query_io,
358 adns_answer **answer_r,
360 int r, maxfd, rsel, rcb;
361 fd_set readfds, writefds, exceptfds;
362 struct timeval tvbuf, *tvp;
365 r= internal_check(ads,query_io,answer_r,context_r);
366 if (r != EWOULDBLOCK) return r;
368 FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
369 adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
370 rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
371 if (rsel==-1) return r;
372 rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
377 int adns_check(adns_state ads,
378 adns_query *query_io,
379 adns_answer **answer_r,
384 r= gettimeofday(&now,0); if (r) return errno;
385 adns__autosys(ads,now);
386 return internal_check(ads,query_io,answer_r,context_r);