3 #include "adns-internal.h"
5 static void autosys(adns_state ads, struct timeval now) {
6 if (ads->iflags & adns_if_noautosys) return;
7 adns_callback(ads,-1,0,0,0);
10 static int callb_checkfd(int maxfd, const fd_set *fds, int fd) {
11 return maxfd<0 || !fds ? 1 :
12 fd<maxfd && FD_ISSET(fd,fds);
15 static void tcpserver_broken(adns_state ads, const char *what, const char *why) {
16 assert(ads->tcpstate == server_connecting || ads->tcpstate == server_connected);
17 warn("nameserver %s TCP connection lost: %s: %s",
18 inet_ntoa(ads->servers[tcpserver].addr,what,why));
19 close(ads->tcpsocket);
20 ads->tcpstate= server_disconnected;
23 int adns_callback(adns_state ads, int maxfd,
24 const fd_set *readfds, const fd_set *writefds,
25 const fd_set *exceptfds) {
26 int skip, dgramlen, count, udpaddrlen;
27 enum adns__tcpstate oldtcpstate;
28 unsigned char udpbuf[UDPMAXDGRAM];
29 struct sockaddr_in udpaddr;
32 oldtcpstate= ads->tcpstate;
34 if (ads->tcpstate == server_connecting) {
35 if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
37 assert(ads->tcprecv.used==0);
38 vbuf_ensure(&ads->tcprecv,1);
39 if (ads->tcprecv.buf) {
40 r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
41 if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
42 debug("nameserver %s TCP connected",
43 inet_ntoa(ads->servers[ads->tcpserver].addr));
44 ads->tcpstate= server_connected;
46 tcpserver_broken(ads,"connect/read","sent data before first request");
47 } else if (errno!=EINTR) {
48 tcpserver_broken(ads,"connect",strerror(errno));
53 if (ads->tcpstate == server_connected) {
54 if (oldtcpstate == server_connected)
55 count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
56 callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
57 (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
58 if (oldtcpstate != server_connected || callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
61 if (ads->tcprecv.used<skip+2) {
64 dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1];
65 if (ads->tcprecv.used<skip+2+dgramlen) {
68 procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver);
69 skip+= 2+dgramlen; continue;
72 ads->tcprecv.used -= skip;
73 memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
74 vbuf_ensure(&ads->tcprecv,want);
75 if (ads->tcprecv.used >= ads->tcprecv.avail) break;
76 r= read(ads->tcpsocket,
77 ads->tcprecv.buf+ads->tcprecv.used,
78 ads->tcprecv.avail-ads->tcprecv.used);
80 ads->tcprecv.used+= r;
83 if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break;
84 if (errno==EINTR) continue;
86 tcpserver_broken(ads->tcpserver,"read",r?strerror(errno):"closed");
90 } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) {
91 tcpserver_broken(ads->tcpserver,"select","exceptional condition detected");
92 } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
93 r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
95 if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) {
96 tcpserver_broken(ads->tcpserver,"write",strerror(errno));
99 ads->tcpsend.used -= r;
100 memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
105 if (callb_checkfd(maxfd,readfds,ads->udpsocket)) {
108 udpaddrlen= sizeof(udpaddr);
109 r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,&udpaddr,&udpaddrlen);
111 if (!(errno == EAGAIN || errno == EWOULDBLOCK ||
112 errno == EINTR || errno == ENOMEM || errno == ENOBUFS))
113 warn("datagram receive error: %s",strerror(errno));
116 if (udpaddrlen != sizeof(udpaddr)) {
117 diag("datagram received with wrong address length %d (expected %d)",
118 udpaddrlen,sizeof(udpaddr));
121 if (udpaddr.sin_family != AF_INET) {
122 diag("datagram received with wrong protocol family %u (expected %u)",
123 udpaddr.sin_family,AF_INET);
126 if (ntohs(udpaddr.sin_port) != NSPORT) {
127 diag("datagram received from wrong port %u (expected %u)",
128 ntohs(udpaddr.sin_port),NSPORT);
132 serv < ads->nservers &&
133 ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr;
135 if (serv >= ads->nservers) {
136 warn("datagram received from unknown nameserver %s",inet_ntoa(udpaddr.sin_addr));
139 procdgram(ads,udpbuf,r,serv);
144 static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
145 struct timeval maxto) {
149 if (!rbuf) { *tvbuf= maxto; *tv_io= tvbuf; return; }
150 if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
153 static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
154 struct timeval now, struct timeval maxtime) {
157 maxtime.tv_sec -= (now.tv_sec-1);
158 maxtime.tv_usec += (1000-now.tv_usec);
159 dr= ldiv(maxtime.tv_usec,1000);
160 maxtime.tv_sec += dr.quot;
161 maxtime.tv_usec -= dr.rem;
162 inter_maxto(tv_io,tvbuf,maxtime);
165 static void localresourcerr(struct timeval **tv_io, struct timeval *tvbuf,
166 const char *syscall) {
167 struct timeval tvto_lr;
169 warn(ads,"local system resources scarce (during %s): %s",syscall,strerror(errno));
170 timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
171 inter_maxto(tv_io, tvbuf, tvto_lr);
175 static void inter_addfd(int *maxfd, fd_set *fds, int fd) {
176 if (fd>=*maxfd) *maxfd= fd+1;
180 void adns_interest(adns_state ads, int *maxfd,
181 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
182 struct timeval **tv_io, struct timeval *tvbuf) {
187 r= gettimeofday(&now,0);
188 if (r) { localresourcerr(tv_io,tvbuf,"gettimeofday"); return; }
190 for (qu= ads->timew; qu; qu= nqu) {
192 if (timercmp(&now,qu->timeout,>)) {
193 DLIST_UNLINK(ads->timew,qu);
194 if (qu->nextudpserver == -1) {
195 query_fail(ads,qu,adns_s_notresponding);
197 DLIST_LINKTAIL(ads->tosend,qu);
200 inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
204 for (qu= ads->tosend; qu; qu= nqu) {
206 quproc_tosend(ads,qu,now);
209 inter_addfd(maxfd,readfds,ads->udpsocket);
211 switch (ads->tcpstate) {
214 case server_connecting:
215 inter_addfd(maxfd,writefds,ads->tcpsocket);
217 case server_connected:
218 inter_addfd(maxfd,readfds,ads->tcpsocket);
219 inter_addfd(maxfd,exceptfds,ads->tcpsocket);
220 if (ads->opbufused) inter_addfd(maxfd,writefds,ads->tcpsocket);
226 static int internal_check(adns_state ads,
227 adns_query *query_io,
228 adns_answer **answer,
234 if (!ads->output.head) return EWOULDBLOCK;
235 qu= ads->output.head;
237 if (qu->id>=0) return EWOULDBLOCK;
239 LIST_UNLINK(ads->output,qu);
241 if (context_r) *context_r= qu->context;
246 int adns_wait(adns_state ads,
247 adns_query *query_io,
248 adns_answer **answer_r,
250 int r, maxfd, rsel, rcb;
251 fd_set readfds, writefds, exceptfds;
252 struct timeval tvbuf, *tvp;
255 r= internal_check(ads,query_io,answer_r,context_r);
256 if (r && r != EWOULDBLOCK) return r;
258 FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
259 adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
260 rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
261 if (rsel==-1) return r;
262 rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
267 int adns_check(adns_state ads,
268 adns_query *query_io,
269 adns_answer **answer_r,
272 return internal_check(ads,query_io,answer_r,context_r);