12 #include <arpa/nameser.h>
13 #include <sys/socket.h>
14 #include <netinet/in.h>
15 #include <arpa/inet.h>
17 #include "adns-internal.h"
19 #define LIST_UNLINK_PART(list,node,part) \
21 if ((node)->back) (node)->back->part next= (node)->part next; \
22 else (list).head= (node)->part next; \
23 if ((node)->next) (node)->next->part back= (node)->part back; \
24 else (list).tail= (node)->part back; \
27 #define LIST_LINK_TAIL_PART(list,node,part) \
29 (node)->part back= 0; \
30 (node)->part next= (list).tail; \
31 if ((list).tail) (list).tail->part back= (node); else (list).part head= (node); \
32 (list).tail= (node); \
35 #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
36 #define LIST_LINK_TAIL_PART(list,node) LIST_LINK_TAIL(list,node,)
38 static void vdebug(adns_state ads, const char *fmt, va_list al) {
39 if (!(ads->iflags & adns_if_debug)) return;
40 fputs("adns debug: ",stderr);
41 vfprintf(stderr,fmt,al);
45 static void debug(adns_state ads, const char *fmt, ...) {
53 static void vdiag(adns_state ads, const char *fmt, va_list al) {
54 if (ads->iflags & adns_if_noerrprint) return;
55 fputs("adns: ",stderr);
56 vfprintf(stderr,fmt,al);
60 static void diag(adns_state ads, const char *fmt, ...) {
68 static void addserver(adns_state ads, struct in_addr addr) {
72 for (i=0; i<ads->nservers; i++) {
73 if (ads->servers[i].addr.s_addr == addr.s_addr) {
74 debug(ads,"duplicate nameserver %s ignored",inet_ntoa(addr));
79 if (ads->nservers>=MAXSERVERS) {
80 diag(ads,"too many nameservers, ignoring %s",inet_ntoa(addr));
84 ss= ads->servers+ads->nservers;
86 ss->state= server_disc;
87 ss->connw.head= ss->connw.tail= 0;
91 static void configparseerr(adns_state ads, const char *fn, int lno,
92 const char *fmt, ...) {
95 if (ads->iflags & adns_if_noerrprint) return;
96 if (lno==-1) fprintf(stderr,"adns: %s: ",fn);
97 else fprintf(stderr,"adns: %s:%d: ",fn,lno);
99 vfprintf(stderr,fmt,al);
104 static void ccf_nameserver(adns_state ads, const char *fn, int lno, const char *buf) {
107 if (!inet_aton(buf,&ia)) {
108 configparseerr(ads,fn,lno,"invalid nameserver address `%s'",buf);
111 debug(ads,"using nameserver %s",inet_ntoa(ia));
115 static void ccf_search(adns_state ads, const char *fn, int lno, const char *buf) {
117 diag(ads,"warning - `search' ignored FIXME");
120 static void ccf_sortlist(adns_state ads, const char *fn, int lno, const char *buf) {
121 diag(ads,"warning - `sortlist' ignored FIXME");
124 static void ccf_options(adns_state ads, const char *fn, int lno, const char *buf) {
126 diag(ads,"warning - `options' ignored FIXME");
129 static void ccf_clearnss(adns_state ads, const char *fn, int lno, const char *buf) {
133 static const struct configcommandinfo {
135 void (*fn)(adns_state ads, const char *fn, int lno, const char *buf);
136 } configcommandinfos[]= {
137 { "nameserver", ccf_nameserver },
138 { "domain", ccf_search },
139 { "search", ccf_search },
140 { "sortlist", ccf_sortlist },
141 { "options", ccf_options },
142 { "clearnameservers", ccf_clearnss },
146 static int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
147 static int ctype_digit(int c) { return c>='0' && c<='9'; }
149 static void readconfig(adns_state ads, const char *filename) {
150 char linebuf[2000], *p, *q;
153 const struct configcommandinfo *ccip;
155 file= fopen(filename,"r");
157 if (errno == ENOENT) {
158 debug(ads,"configuration file `%s' does not exist",filename);
161 diag(ads,"cannot open configuration file `%s': %s",filename,strerror(errno));
165 for (lno=1; fgets(linebuf,sizeof(linebuf),file); lno++) {
168 if (linebuf[l-1] != '\n' && !feof(file)) {
169 diag(ads,"%s:%d: line too long",filename,lno);
170 while ((c= getc(file)) != EOF && c != '\n') { }
174 while (l>0 && ctype_whitespace(linebuf[l-1])) l--;
177 while (ctype_whitespace(*p)) p++;
178 if (*p == '#' || *p == '\n') continue;
180 while (*q && !ctype_whitespace(*q)) q++;
181 for (ccip=configcommandinfos;
182 ccip->name && strncmp(ccip->name,p,q-p);
185 diag(ads,"%s:%d: unknown configuration directive `%.*s'",filename,lno,q-p,p);
188 while (ctype_whitespace(*q)) q++;
189 ccip->fn(ads,filename,lno,q);
192 diag(ads,"%s:%d: read error: %s",filename,lno,strerror(errno));
197 static const char *instrum_getenv(adns_state ads, const char *envvar) {
200 value= getenv(envvar);
201 if (!value) debug(ads,"environment variable %s not set",envvar);
202 else debug(ads,"environment variable %s set to `%s'",envvar,value);
206 static void readconfigenv(adns_state ads, const char *envvar) {
207 const char *filename;
209 if (ads->iflags & adns_if_noenv) {
210 debug(ads,"not checking environment variable `%s'",envvar);
213 filename= instrum_getenv(ads,envvar);
214 if (filename) readconfig(ads,filename);
217 int adns_init(adns_state *ads_r, adns_initflags flags) {
219 const char *res_options, *adns_res_options;
220 struct protoent *proto;
223 ads= malloc(sizeof(*ads)); if (!ads) return errno;
224 ads->tosend.head= ads->tosend.tail= 0;
225 ads->timew.head= ads->timew.tail= 0;
226 ads->childw.head= ads->childw.tail= 0;
227 ads->output.head= ads->output.tail= 0;
232 ads->tcpbufavail= ads->tcpbufused= ads->tcpbufdone= 0;
238 res_options= instrum_getenv(ads,"RES_OPTIONS");
239 adns_res_options= instrum_getenv(ads,"ADNS_RES_OPTIONS");
240 ccf_options(ads,"RES_OPTIONS",-1,res_options);
241 ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
243 readconfig(ads,"/etc/resolv.conf");
244 readconfigenv(ads,"RES_CONF");
245 readconfigenv(ads,"ADNS_RES_CONF");
247 ccf_options(ads,"RES_OPTIONS",-1,res_options);
248 ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
250 ccf_search(ads,"LOCALDOMAIN",-1,instrum_getenv(ads,"LOCALDOMAIN"));
251 ccf_search(ads,"ADNS_LOCALDOMAIN",-1,instrum_getenv(ads,"ADNS_LOCALDOMAIN"));
253 if (!ads->nservers) {
255 if (ads->iflags & adns_if_debug)
256 fprintf(stderr,"adns: no nameservers, using localhost\n");
257 ia.s_addr= INADDR_LOOPBACK;
261 proto= getprotobyname("udp"); if (!proto) { r= ENOPROTOOPT; goto x_free; }
262 ads->udpsocket= socket(AF_INET,SOCK_DGRAM,proto->p_proto);
263 if (!ads->udpsocket) { r= errno; goto x_closeudp; }
269 close(ads->udpsocket);
275 static void query_fail(adns_state ads, adns_query qu, adns_status stat) {
279 if (!ans) ans= malloc(sizeof(*qu->answer));
288 LIST_LINK_TAIL(ads->output,qu);
291 int adns_finish(adns_state ads) {
295 static void autosys(adns_state ads, struct timeval now) {
296 if (ads->iflags & adns_if_noautosys) return;
297 adns_callback(ads,-1,0,0,0);
300 void adns_cancel(adns_state ads, adns_query query) {
304 static int callb_checkfd(int maxfd, const fd_set *fds, int fd) {
305 return maxfd<0 || !fds ? 1 :
306 fd<maxfd && FD_ISSET(fd,fds);
309 int adns_callback(adns_state ads, int maxfd,
310 const fd_set *readfds, const fd_set *writefds,
311 const fd_set *exceptfds) {
312 int skip, dgramlen, count;
313 enum adns__tcpstate oldtcpstate;
316 oldtcpstate= ads->tcpstate;
318 if (ads->tcpstate == server_connecting) {
319 if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
321 assert(ads->tcprecv.used==0);
322 vbuf_ensure(&ads->tcprecv,1);
323 if (ads->tcprecv.buf) {
324 r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
325 if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
326 diag("nameserver %s TCP connection made",
327 inet_ntoa(ads->servers[ads->tcpserver].addr));
328 ads->tcpstate= server_connected;
330 tcpserver_broken(ads,"connect/read","sent data before first request");
331 } else if (errno!=EINTR) {
332 tcpserver_broken(ads,"connect",strerror(errno));
337 if (ads->tcpstate == server_connected) {
338 if (oldtcpstate == server_connected)
339 count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
340 callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
341 (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
342 if (oldtcpstate != server_connected || callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
345 if (ads->tcprecv.used<skip+2) {
348 dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1];
349 if (ads->tcprecv.used<skip+2+dgramlen) {
352 procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,-1);
353 skip+= 2+dgramlen; continue;
356 Ads->tcprecv.used -= skip;
357 memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
358 vbuf_ensure(&ads->tcprecv,want);
359 if (ads->tcprecv.used >= ads->tcprecv.avail) break;
360 r= read(ads->tcpsocket,
361 ads->tcprecv.buf+ads->tcprecv.used,
362 ads->tcprecv.avail-ads->tcprecv.used);
364 ads->tcprecv.used+= r;
367 if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break;
368 if (errno==EINTR) continue;
370 tcpserver_broken(ads->tcpserver,"read",r?strerror(errno):"closed");
374 } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) {
375 tcpserver_broken(ads->tcpserver,"select","exceptional condition detected");
376 } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
377 r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
379 if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) {
380 tcpserver_broken(ads->tcpserver,"write",strerror(errno));
383 ads->tcpsend.used -= r;
384 memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
400 vbuf_ensure(&ads->tcprecv,2);
401 vbuf_ensure(&ads->tcprecv,
402 if (ads->tcprecv.avail<2) break;
403 if (ads->tcprecv.used
405 if (ads->tcprecv.used<2 && ads->tcprecv.avail
406 if (ads->tcprecv.used<2 && ads->tcprecv.avail
407 r= read(ads->tcpsocket,
408 if (adns->tcprecv.used<2) {
411 if (ads->tcpstate != server_disc) {
415 if (maxfd<0 || !readfds || (FD_ISSET
420 diag("nameserver #%d (%s) TCP connection died: %s",
421 inet_ntoa(ads->servers[tcpserver].addr),
423 static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
424 struct timeval maxto) {
428 if (!rbuf) { *tvbuf= maxto; *tv_io= tvbuf; return; }
429 if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
432 static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
433 struct timeval now, struct timeval maxtime) {
436 maxtime.tv_sec -= (now.tv_sec-1);
437 maxtime.tv_usec += (1000-now.tv_usec);
438 dr= ldiv(maxtime.tv_usec,1000);
439 maxtime.tv_sec += dr.quot;
440 maxtime.tv_usec -= dr.rem;
441 inter_maxto(tv_io,tvbuf,maxtime);
444 static void localresourcerr(struct timeval **tv_io, struct timeval *tvbuf,
445 const char *syscall) {
446 struct timeval tvto_lr;
448 diag(ads,"local system resources scarce (during %s): %s",syscall,strerror(errno));
449 timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
450 inter_maxto(tv_io, tvbuf, tvto_lr);
454 static inline void timevaladd(struct timeval *tv_io, long ms) {
458 tmp.tv_usec += (ms%1000)*1000;
459 tmp.tv_sec += ms/1000;
460 if (tmp.tv_usec >= 1000) { tmp.tv_sec++; tmp.tv_usec -= 1000; }
464 static void inter_addfd(int *maxfd, fd_set *fds, int fd) {
465 if (fd>=*maxfd) *maxfd= fd+1;
469 void adns_interest(adns_state ads, int *maxfd,
470 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
471 struct timeval **tv_io, struct timeval *tvbuf) {
476 r= gettimeofday(&now,0);
477 if (r) { localresourcerr(tv_io,tvbuf,"gettimeofday"); return; }
479 for (qu= ads->timew; qu; qu= nqu) {
481 if (timercmp(&now,qu->timeout,>)) {
482 DLIST_UNLINK(ads->timew,qu);
483 if (qu->nextudpserver == -1) {
484 query_fail(ads,qu,adns_s_notresponding);
486 DLIST_LINKTAIL(ads->tosend,qu);
489 inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
493 for (qu= ads->tosend; qu; qu= nqu) {
495 quproc_tosend(ads,qu,now);
498 inter_addfd(maxfd,readfds,ads->udpsocket);
499 switch (ads->tcpstate) {
502 case server_connecting:
503 inter_addfd(maxfd,writefds,ads->tcpsocket);
505 case server_connected:
506 inter_addfd(maxfd,readfds,ads->tcpsocket);
507 inter_addfd(maxfd,exceptfds,ads->tcpsocket);
508 if (ads->opbufused) inter_addfd(maxfd,writefds,ads->tcpsocket);
515 static int internal_check(adns_state ads,
516 adns_query *query_io,
517 adns_answer **answer,
523 if (!ads->output.head) return EWOULDBLOCK;
524 qu= ads->output.head;
526 if (qu->id>=0) return EWOULDBLOCK;
528 LIST_UNLINK(ads->output,qu);
530 if (context_r) *context_r= qu->context;
535 int adns_wait(adns_state ads,
536 adns_query *query_io,
537 adns_answer **answer_r,
539 int r, maxfd, rsel, rcb;
540 fd_set readfds, writefds, exceptfds;
541 struct timeval tvbuf, *tvp;
544 r= internal_check(ads,query_io,answer_r,context_r);
545 if (r && r != EWOULDBLOCK) return r;
546 FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
548 adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
549 rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
550 if (rsel==-1) return r;
551 rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
556 int adns_check(adns_state ads,
557 adns_query *query_io,
558 adns_answer **answer_r,
561 return internal_check(ads,query_io,answer_r,context_r);
564 int adns_synchronous(adns_state ads,
567 adns_queryflags flags,
568 adns_answer **answer_r) {
572 r= adns_submit(ads,owner,type,flags,0,&qu);
576 r= adns_wait(ads,&qu,answer_r,0);
578 if (r) adns_cancel(ads,qu);
582 static adns_status mkquery(adns_state ads, const char *owner, int ol, int id,
583 adns_rrtype type, adns_queryflags flags, int *qml_r) {
584 int ll, c, nlabs, qbufreq;
585 unsigned char label[255], *nqbuf;
588 #define MKQUERY_ADDB(b) *nqbuf++= (b)
589 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
591 qbufreq= 12+strlen(owner)+3;
592 if (ads->qbufavail < qbufreq) {
593 nqbuf= realloc(ads->qbuf,qbufreq);
594 if (!nqbuf) return adns_s_nolocalmem;
595 ads->qbuf= nqbuf; ads->qbufavail= qbufreq;
600 MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
601 MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
602 MKQUERY_ADDW(1); /* QDCOUNT=1 */
603 MKQUERY_ADDW(0); /* ANCOUNT=0 */
604 MKQUERY_ADDW(0); /* NSCOUNT=0 */
605 MKQUERY_ADDW(0); /* ARCOUNT=0 */
606 p= owner; pe= owner+ol;
608 if (!*p) return adns_s_invaliddomain;
611 while (p!=pe && (c= *p++)!='.') {
613 if (!(flags & adns_f_anyquote)) return adns_s_invaliddomain;
614 if (ctype_digit(p[0])) {
615 if (ctype_digit(p[1]) && ctype_digit(p[2])) {
616 c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
617 if (c >= 256) return adns_s_invaliddomain;
619 return adns_s_invaliddomain;
621 } else if (!(c= *p++)) {
622 return adns_s_invaliddomain;
625 if (!(flags & adns_f_anyquote)) {
626 if ((c >= '0' && c <= '9') || c == '-') {
627 if (!ll) return adns_s_invaliddomain;
628 } else if ((c < 'a' || c > 'z') && (c < 'A' && c > 'Z')) {
629 return adns_s_invaliddomain;
632 if (ll == sizeof(label)) return adns_s_invaliddomain;
635 if (!ll) return adns_s_invaliddomain;
636 if (nlabs++ > 63) return adns_s_invaliddomain;
638 memcpy(nqbuf,label,ll); nqbuf+= ll;
642 MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
643 MKQUERY_ADDW(1); /* QCLASS=IN */
645 *qml_r= nqbuf - ads->qbuf;
650 static adns_query allocquery(adns_state ads, const char *owner, int ol,
651 int qml, int id, adns_rrtype type,
652 adns_queryflags flags, void *context) {
656 qu= malloc(sizeof(*qu)+ol+1+qml); if (!qu) return 0;
657 qu->next= qu->back= qu->parent= 0;
658 qu->children.head= qu->children.tail= 0;
659 qu->siblings.next= qu->siblings.back= 0;
664 qu->context= context;
666 qu->sentudp= qu->senttcp= 0;
668 memcpy(qu->owner,owner,ol); qu->owner[ol]= 0;
669 qu->querymsg= qm= qu->owner+ol+1;
670 memcpy(qm,ads->qbuf,qml);
675 static int failsubmit(adns_state ads, void *context, adns_query *query_r,
676 adns_rrtype type, adns_queryflags flags,
677 int id, adns_status stat) {
680 qu= allocquery(ads,0,0,0,id,type,flags,context); if (!qu) return errno;
681 query_fail(ads,qu,stat);
686 static void quproc_tosend(adns_state ads, adns_query qu, struct timeval now) {
687 /* Query must be on the `tosend' queue, and guarantees to remove it. */
688 struct sockaddr_in servaddr;
691 if (qu->nextudpserver != -1) {
692 if (qu->udpretries >= UDPMAXRETRIES) {
693 DLIST_UNLINK(ads->tosend,qu);
694 query_fail(ads,qu,adns_s_notresponding);
697 serv= qu->nextudpserver;
698 memset(&servaddr,0,sizeof(servaddr));
699 servaddr.sin_family= AF_INET;
700 servaddr.sin_addr= ads->servers[serv].addr;
701 servaddr.sin_port= htons(53);
702 r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr));
703 if (r<0 && errno == EMSGSIZE) {
704 qu->nextudpserver= -1;
707 diag("sendto %s failed: %s",inet_ntoa(servaddr.sin_addr),strerror(errno));
709 DLIST_UNLINK(ads->tosend,qu);
710 timevaladd(&now,UDPRETRYMS);
712 qu->sentudp |= (1<<serv);
713 qu->nextudpserver= (serv+1)%ads->nservers;
715 DLIST_LINKTAIL(ads->timew,qu);
721 serv= tcpserver_get(ads);
722 if (serv<0) { r=0; break; }
723 if (ads->opbufused) { r=0; break; }
724 r= write(ads->tcpsocket,qu->querymsg,qu->querylen);
726 if (errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
727 errno == ENOBUFS || errno == ENOMEM) {
730 tcpserver_broken(serv);
732 if (r < qu->querylen) {
733 newopbufused= qu->opbufused + (qu->querylen-r);
734 if (newopbufused > ads->opbufavail) {
735 newopbufavail= ads->newopbufused<<1;
736 newopbuf= realloc(newopbufavail);
738 DLIST_UNLINK(ads->tosend,qu);
739 query_fail(ads,qu,adns_s_nolocalmem);
742 ads->opbuf= newopbuf;
743 ads->opbufavail= newopbufavail;
745 memcpy(ads->opbuf+ads->opbufused,qu->querymsg+r,qu->querylen-r);
746 ads->opbufused= newopbufused;
748 DLIST_UNLINK(ads->tosend,qu);
749 timevaladd(&now,TCPMS);
751 qu->senttcp |= (1<<qu->nextserver);
752 DLIST_LINKTAIL(ads->timew,qu);
755 int adns_submit(adns_state ads,
758 adns_queryflags flags,
760 adns_query *query_r) {
768 if (ol<=1 || ol>MAXDNAME+1)
769 return failsubmit(ads,context,query_r,type,flags,id,adns_s_invaliddomain);
770 if (owner[ol-1]=='.' && owner[ol-2]!='\\') { flags &= ~adns_f_search; ol--; }
772 stat= mkquery(ads,owner,ol,id,type,flags,&qml);
773 if (stat) return failsubmit(ads,context,query_r,type,flags,id,stat);
775 qu= allocquery(ads,owner,ol,qml,id,type,flags,context); if (!qu) return errno;
776 if (qu->flags & adns_f_usevc) qu->udpretries= -1;
777 LIST_LINK_TAIL(ads->tosend,qu);
779 r= gettimeofday(&now,0); if (r) return;
780 quproc_tosend(ads,qu,now);