656b2da9 |
1 | /**/ |
2 | |
37e28fde |
3 | #include "adns-internal.h" |
4 | |
656b2da9 |
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); |
8 | } |
9 | |
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); |
13 | } |
14 | |
37e28fde |
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; |
21 | |
22 | |
656b2da9 |
23 | int adns_callback(adns_state ads, int maxfd, |
24 | const fd_set *readfds, const fd_set *writefds, |
25 | const fd_set *exceptfds) { |
37e28fde |
26 | int skip, dgramlen, count, udpaddrlen; |
656b2da9 |
27 | enum adns__tcpstate oldtcpstate; |
37e28fde |
28 | unsigned char udpbuf[UDPMAXDGRAM]; |
29 | struct sockaddr_in udpaddr; |
656b2da9 |
30 | |
31 | count= 0; |
32 | oldtcpstate= ads->tcpstate; |
33 | |
34 | if (ads->tcpstate == server_connecting) { |
35 | if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) { |
36 | count++; |
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))) { |
37e28fde |
42 | debug("nameserver %s TCP connected", |
43 | inet_ntoa(ads->servers[ads->tcpserver].addr)); |
656b2da9 |
44 | ads->tcpstate= server_connected; |
45 | } else if (r>0) { |
46 | tcpserver_broken(ads,"connect/read","sent data before first request"); |
47 | } else if (errno!=EINTR) { |
48 | tcpserver_broken(ads,"connect",strerror(errno)); |
49 | } |
50 | } |
51 | } |
52 | } |
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)) { |
59 | skip= 0; |
60 | for (;;) { |
61 | if (ads->tcprecv.used<skip+2) { |
62 | want= 2; |
63 | } else { |
64 | dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1]; |
65 | if (ads->tcprecv.used<skip+2+dgramlen) { |
66 | want= 2+dgramlen; |
67 | } else { |
37e28fde |
68 | procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver); |
656b2da9 |
69 | skip+= 2+dgramlen; continue; |
70 | } |
71 | } |
37e28fde |
72 | ads->tcprecv.used -= skip; |
656b2da9 |
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); |
79 | if (r>0) { |
80 | ads->tcprecv.used+= r; |
81 | } else { |
82 | if (r<0) { |
83 | if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break; |
84 | if (errno==EINTR) continue; |
85 | } |
86 | tcpserver_broken(ads->tcpserver,"read",r?strerror(errno):"closed"); |
87 | break; |
88 | } |
89 | } |
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); |
94 | if (r<0) { |
95 | if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) { |
96 | tcpserver_broken(ads->tcpserver,"write",strerror(errno)); |
97 | } |
98 | } else if (r>0) { |
99 | ads->tcpsend.used -= r; |
100 | memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used); |
101 | } |
102 | } |
103 | } |
104 | |
37e28fde |
105 | if (callb_checkfd(maxfd,readfds,ads->udpsocket)) { |
106 | count++; |
107 | for (;;) { |
108 | udpaddrlen= sizeof(udpaddr); |
109 | r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,&udpaddr,&udpaddrlen); |
110 | if (r<0) { |
111 | if (!(errno == EAGAIN || errno == EWOULDBLOCK || |
112 | errno == EINTR || errno == ENOMEM || errno == ENOBUFS)) |
113 | warn("datagram receive error: %s",strerror(errno)); |
114 | break; |
115 | } |
116 | if (udpaddrlen != sizeof(udpaddr)) { |
117 | diag("datagram received with wrong address length %d (expected %d)", |
118 | udpaddrlen,sizeof(udpaddr)); |
119 | continue; |
120 | } |
121 | if (udpaddr.sin_family != AF_INET) { |
122 | diag("datagram received with wrong protocol family %u (expected %u)", |
123 | udpaddr.sin_family,AF_INET); |
124 | continue; |
125 | } |
126 | if (ntohs(udpaddr.sin_port) != NSPORT) { |
127 | diag("datagram received from wrong port %u (expected %u)", |
128 | ntohs(udpaddr.sin_port),NSPORT); |
129 | continue; |
130 | } |
131 | for (serv= 0; |
132 | serv < ads->nservers && |
133 | ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr; |
134 | serv++); |
135 | if (serv >= ads->nservers) { |
136 | warn("datagram received from unknown nameserver %s",inet_ntoa(udpaddr.sin_addr)); |
137 | continue; |
138 | } |
139 | procdgram(ads,udpbuf,r,serv); |
656b2da9 |
140 | } |
37e28fde |
141 | } |
656b2da9 |
142 | } |
656b2da9 |
143 | |
144 | static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf, |
145 | struct timeval maxto) { |
146 | struct timeval rbuf; |
147 | |
148 | rbuf= *tv_io; |
149 | if (!rbuf) { *tvbuf= maxto; *tv_io= tvbuf; return; } |
150 | if (timercmp(rbuf,&maxto,>)) *rbuf= maxto; |
151 | } |
152 | |
153 | static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf, |
154 | struct timeval now, struct timeval maxtime) { |
155 | ldiv_t dr; |
156 | |
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); |
163 | } |
164 | |
165 | static void localresourcerr(struct timeval **tv_io, struct timeval *tvbuf, |
166 | const char *syscall) { |
167 | struct timeval tvto_lr; |
168 | |
37e28fde |
169 | warn(ads,"local system resources scarce (during %s): %s",syscall,strerror(errno)); |
656b2da9 |
170 | timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS); |
171 | inter_maxto(tv_io, tvbuf, tvto_lr); |
172 | return; |
173 | } |
174 | |
175 | static void inter_addfd(int *maxfd, fd_set *fds, int fd) { |
176 | if (fd>=*maxfd) *maxfd= fd+1; |
177 | FD_SET(fd,fds); |
178 | } |
179 | |
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) { |
183 | struct timeval now; |
184 | adns_query qu; |
185 | int r; |
186 | |
187 | r= gettimeofday(&now,0); |
188 | if (r) { localresourcerr(tv_io,tvbuf,"gettimeofday"); return; } |
189 | |
190 | for (qu= ads->timew; qu; qu= nqu) { |
191 | nqu= qu->next; |
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); |
196 | } else { |
197 | DLIST_LINKTAIL(ads->tosend,qu); |
198 | } |
199 | } else { |
200 | inter_maxtoabs(tv_io,tvbuf,now,qu->timeout); |
201 | } |
202 | } |
203 | |
204 | for (qu= ads->tosend; qu; qu= nqu) { |
205 | nqu= qu->next; |
206 | quproc_tosend(ads,qu,now); |
207 | } |
208 | |
209 | inter_addfd(maxfd,readfds,ads->udpsocket); |
37e28fde |
210 | |
656b2da9 |
211 | switch (ads->tcpstate) { |
212 | case server_disc: |
213 | break; |
214 | case server_connecting: |
215 | inter_addfd(maxfd,writefds,ads->tcpsocket); |
216 | break; |
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); |
221 | default: |
222 | abort(); |
223 | } |
656b2da9 |
224 | } |
225 | |
226 | static int internal_check(adns_state ads, |
227 | adns_query *query_io, |
228 | adns_answer **answer, |
229 | void **context_r) { |
230 | adns_query qu; |
231 | |
232 | qu= *query_io; |
233 | if (!qu) { |
234 | if (!ads->output.head) return EWOULDBLOCK; |
235 | qu= ads->output.head; |
236 | } else { |
237 | if (qu->id>=0) return EWOULDBLOCK; |
238 | } |
239 | LIST_UNLINK(ads->output,qu); |
240 | *answer= qu->answer; |
241 | if (context_r) *context_r= qu->context; |
242 | free(qu); |
243 | return 0; |
244 | } |
245 | |
246 | int adns_wait(adns_state ads, |
247 | adns_query *query_io, |
248 | adns_answer **answer_r, |
249 | void **context_r) { |
250 | int r, maxfd, rsel, rcb; |
251 | fd_set readfds, writefds, exceptfds; |
252 | struct timeval tvbuf, *tvp; |
253 | |
254 | for (;;) { |
255 | r= internal_check(ads,query_io,answer_r,context_r); |
256 | if (r && r != EWOULDBLOCK) return r; |
656b2da9 |
257 | maxfd= 0; tvp= 0; |
37e28fde |
258 | FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds); |
656b2da9 |
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); |
263 | assert(rcb==rsel); |
264 | } |
265 | } |
266 | |
267 | int adns_check(adns_state ads, |
268 | adns_query *query_io, |
269 | adns_answer **answer_r, |
270 | void **context_r) { |
271 | autosys(ads); |
272 | return internal_check(ads,query_io,answer_r,context_r); |
273 | } |