14 Maxreply= 8192, /* was 512 */
15 Maxrrr= 32, /* was 16 */
18 Defmaxage= 60*60, /* default domain name max. age */
24 typedef struct Mfile Mfile;
25 typedef struct Job Job;
26 typedef struct Network Network;
28 int vers; /* incremented each clone/attach */
30 static volatile int stop;
32 /* holds data to be returned via read of /net/dns, perhaps multiple reads */
35 Mfile *next; /* next free mfile */
41 int type; /* reply type */
43 ushort rr[Maxrrr]; /* offset of rr's */
44 ushort nrr; /* number of rr's */
48 * active local requests
62 Mfile *inuse; /* active mfile's */
67 int maxage = Defmaxage;
76 char *zonerefreshprogram;
78 char *logfile = "dns"; /* or "dns.test" */
82 int addforwtarg(char *);
83 int fillreply(Mfile*, int);
86 void mountinit(char*, char*);
88 void rattach(Job*, Mfile*);
90 void rclunk(Job*, Mfile*);
91 void rcreate(Job*, Mfile*);
93 void ropen(Job*, Mfile*);
94 void rread(Job*, Mfile*);
95 void rremove(Job*, Mfile*);
96 void rstat(Job*, Mfile*);
98 char* rwalk(Job*, Mfile*);
99 void rwrite(Job*, Mfile*, Request*);
100 void rwstat(Job*, Mfile*);
101 void sendmsg(Job*, char*);
102 void setext(char*, int, char*);
104 static char *lookupqueryold(Job*, Mfile*, Request*, char*, char*, int, int);
105 static char *lookupquerynew(Job*, Mfile*, Request*, char*, char*, int, int);
106 static char *respond(Job*, Mfile*, RR*, char*, int, int);
111 fprint(2, "usage: %s [-FnorRst] [-a maxage] [-f ndb-file] [-N target] "
112 "[-T forwip] [-x netmtpt] [-z refreshprog]\n", argv0);
117 main(int argc, char *argv[])
120 char servefile[Maxpath], ext[Maxpath];
123 setnetmtpt(mntpt, sizeof mntpt, nil);
127 maxage = atol(EARGF(usage()));
136 dbfile = EARGF(usage());
139 cfg.justforw = cfg.resolver = 1;
145 target = atol(EARGF(usage()));
150 cfg.straddle = 1; /* straddle inside & outside networks */
159 cfg.serve = 1; /* serve network */
166 addforwtarg(EARGF(usage()));
169 setnetmtpt(mntpt, sizeof mntpt, EARGF(usage()));
170 setext(ext, sizeof ext, mntpt);
173 zonerefreshprogram = EARGF(usage());
183 mainmem->flags |= POOL_NOREUSE | POOL_ANTAGONISM;
184 mainmem->flags |= POOL_ANTAGONISM;
185 rfork(RFREND|RFNOTEG);
187 cfg.inside = (*mntpt == '\0' || strcmp(mntpt, "/net") == 0);
189 /* start syslog before we fork */
190 fmtinstall('F', fcallfmt);
192 dnslog("starting %s%sdns %s%s%son %s",
193 (cfg.straddle? "straddling ": ""),
194 (cfg.cachedb? "caching ": ""),
195 (cfg.serve? "udp server ": ""),
196 (cfg.justforw? "forwarding-only ": ""),
197 (cfg.resolver? "resolver ": ""), mntpt);
200 now = time(nil); /* open time files before we fork */
203 snprint(servefile, sizeof servefile, "#s/dns%s", ext);
204 dir = dirstat(servefile);
206 sysfatal("%s exists; another dns instance is running",
209 // unmount(servefile, mntpt);
210 // remove(servefile);
212 mountinit(servefile, mntpt); /* forks, parent exits */
218 if (cfg.straddle && !seerootns())
219 dnslog("straddle server misconfigured; can't see root name servers");
221 * fork without sharing heap.
222 * parent waits around for child to die, then forks & restarts.
223 * child may spawn udp server, notify procs, etc.; when it gets too
224 * big, it kills itself and any children.
225 * /srv/dns and /net/dns remain open and valid.
228 kid = rfork(RFPROC|RFFDG|RFNOTEG);
231 sysfatal("fork failed: %r");
240 while ((pid = waitpid()) != kid && pid != -1)
244 dnslog("dns restarting");
249 * if a mount point is specified, set the cs extension to be the mount point
250 * with '_'s replacing '/'s
253 setext(char *ext, int n, char *p)
258 for(i = 0; i < n; i++){
270 mountinit(char *service, char *mntpt)
277 abort(); /* "pipe failed" */;
278 /* copy namespace to avoid a deadlock */
279 switch(rfork(RFFDG|RFPROC|RFNAMEG)){
280 case 0: /* child: hang around and (re)start main proc */
282 procsetname("%s restarter", mntpt);
285 abort(); /* "fork failed\n" */;
286 default: /* parent: make /srv/dns, mount it, exit */
292 f = create(service, 1, 0666);
294 abort(); /* service */;
295 snprint(buf, sizeof buf, "%d", p[1]);
296 if(write(f, buf, strlen(buf)) != strlen(buf))
297 abort(); /* "write %s", service */;
301 * put ourselves into the file system
303 if(mount(p[1], -1, mntpt, MAFTER, "") < 0)
304 fprint(2, "dns mount failed: %r\n");
307 mfd[0] = mfd[1] = p[0];
311 newfid(int fid, int needunused)
316 for(mf = mfalloc.inuse; mf != nil; mf = mf->next)
323 mf = emalloc(sizeof(*mf));
325 mf->user = estrdup("dummy");
326 mf->next = mfalloc.inuse;
338 for(l = &mfalloc.inuse; *l != nil; l = &(*l)->next)
342 memset(mf, 0, sizeof *mf); /* cause trouble */
348 sysfatal("freeing unused fid");
352 copyfid(Mfile *mf, int fid)
356 nmf = newfid(fid, 1);
360 free(nmf->user); /* estrdup("dummy") */
361 nmf->user = estrdup(mf->user);
362 nmf->qid.type = mf->qid.type;
363 nmf->qid.path = mf->qid.path;
364 nmf->qid.vers = vers++;
373 job = emalloc(sizeof *job);
377 job->request.tag = -1;
388 for(l = &joblist; *l; l = &(*l)->next)
391 memset(job, 0, sizeof *job); /* cause trouble */
404 for(job = joblist; job; job = job->next)
405 if(job->request.tag == tag && job->request.type != Tflush){
416 volatile uchar mdata[IOHDRSZ + Maxfdata];
419 volatile Request req;
421 memset(&req, 0, sizeof req);
423 * a slave process is sometimes forked to wait for replies from other
424 * servers. The master process returns immediately via a longjmp
432 procsetname("%d %s/dns Twrites of %d 9p rpcs read; %d alarms",
433 stats.qrecvd9p, mntpt, stats.qrecvd9prpc, stats.alarms);
434 n = read9pmsg(mfd[0], mdata, sizeof mdata);
436 dnslog("error reading 9P from %s: %r", mntpt);
437 sleep(2000); /* don't thrash after read error */
443 if(convM2S(mdata, n, &job->request) != n){
447 mf = newfid(job->request.fid, 0);
449 dnslog("%F", &job->request);
451 getactivity(&req, 0);
452 req.aborttime = timems() + Maxreqtm;
455 switch(job->request.type){
457 warning("unknown request type %d", job->request.type);
484 /* &req is handed to dnresolve() */
485 rwrite(job, mf, &req);
504 * slave processes die after replying
513 /* kill any udp server, notifier, etc. processes */
514 postnote(PNGROUP, getpid(), "die");
521 if(job->request.msize > IOHDRSZ + Maxfdata)
522 job->reply.msize = IOHDRSZ + Maxfdata;
524 job->reply.msize = job->request.msize;
525 if(strncmp(job->request.version, "9P2000", 6) != 0)
526 sendmsg(job, "unknown 9P version");
528 job->reply.version = "9P2000";
536 sendmsg(job, "dns: authentication not required");
540 * don't flush till all the slaves are done
545 flushjob(job->request.oldtag);
550 rattach(Job *job, Mfile *mf)
554 mf->user = estrdup(job->request.uname);
555 mf->qid.vers = vers++;
556 mf->qid.type = QTDIR;
558 job->reply.qid = mf->qid;
563 rwalk(Job *job, Mfile *mf)
573 elems = job->request.wname;
574 nelems = job->request.nwname;
575 job->reply.nwqid = 0;
577 if(job->request.newfid != job->request.fid){
579 nmf = copyfid(mf, job->request.newfid);
581 err = "clone bad newfid";
586 /* else nmf will be nil */
591 for(i=0; i<nelems && i<MAXWELEM; i++){
592 if((qid.type & QTDIR) == 0){
593 err = "not a directory";
596 if (strcmp(elems[i], "..") == 0 ||
597 strcmp(elems[i], ".") == 0){
601 job->reply.wqid[i] = qid;
605 if(strcmp(elems[i], "dns") == 0){
610 err = "file does not exist";
615 if(nmf != nil && (err!=nil || job->reply.nwqid<nelems))
624 ropen(Job *job, Mfile *mf)
630 mode = job->request.mode;
631 if(mf->qid.type & QTDIR)
633 err = "permission denied";
634 job->reply.qid = mf->qid;
635 job->reply.iounit = 0;
640 rcreate(Job *job, Mfile *mf)
643 sendmsg(job, "creation permission denied");
647 rread(Job *job, Mfile *mf)
659 off = job->request.offset;
660 cnt = job->request.count;
662 job->reply.data = (char*)buf;
663 if(mf->qid.type & QTDIR){
666 memset(&dir, 0, sizeof dir);
668 dir.qid.type = QTFILE;
673 dir.uid = dir.gid = dir.muid = mf->user;
674 dir.atime = dir.mtime = clock; /* wrong */
675 n = convD2M(&dir, buf, sizeof buf);
678 err = "negative read offset";
680 /* first offset will always be zero */
681 for(i = 1; i <= mf->nrr; i++)
685 if(off + cnt > mf->rr[i])
690 job->reply.data = mf->reply + off;
693 job->reply.count = n;
698 rwrite(Job *job, Mfile *mf, Request *req)
700 int rooted, wantsav, send;
702 char *err, *p, *atype;
706 cnt = job->request.count;
708 if(mf->qid.type & QTDIR)
709 err = "can't write directory";
710 else if (job->request.offset != 0)
711 err = "writing at non-zero offset";
712 else if(cnt >= Maxrequest)
713 err = "request too long";
719 job->request.data[cnt] = 0;
720 if(cnt > 0 && job->request.data[cnt-1] == '\n')
721 job->request.data[cnt-1] = 0;
726 // dnslog("rwrite got: %s", job->request.data);
728 if(strcmp(job->request.data, "age")==0){
729 dnslog("dump, age & dump forced");
730 dndump("/lib/ndb/dnsdump1");
732 dndump("/lib/ndb/dnsdump2");
733 } else if(strcmp(job->request.data, "debug")==0)
735 else if(strcmp(job->request.data, "dump")==0)
736 dndump("/lib/ndb/dnsdump");
737 else if(strcmp(job->request.data, "poolcheck")==0)
739 else if(strcmp(job->request.data, "refresh")==0)
741 else if(strcmp(job->request.data, "restart")==0)
743 else if(strcmp(job->request.data, "stats")==0)
744 dnstats("/lib/ndb/dnsstats");
745 else if(strncmp(job->request.data, "target ", 7)==0){
746 target = atol(job->request.data + 7);
747 dnslog("target set to %ld", target);
754 * kill previous reply
760 * break up request (into a name and a type)
762 atype = strchr(job->request.data, ' ');
764 snprint(errbuf, sizeof errbuf, "illegal request %s",
774 if(strcmp(atype, "trace") == 0){
777 if(*job->request.data)
778 trace = estrdup(job->request.data);
784 /* normal request: domain [type] */
786 mf->type = rrtype(atype);
788 snprint(errbuf, sizeof errbuf, "unknown type %s", atype);
794 if(p >= job->request.data && *p == '.'){
800 p = job->request.data;
807 err = lookupqueryold(job, mf, req, errbuf, p, wantsav, rooted);
810 job->reply.count = cnt;
816 * rr = dnresolve(buf, Cin, type, &req, 0, 0, Recurse, rooted, 0);
817 * which generates a UDP query, which eventually calls
818 * dnserver(&reqmsg, &repmsg, &req, buf, rcode);
820 * rp = dnresolve(name, Cin, type, req, &mp->an, 0, recurse, 1, 0);
822 * but here we just call dnresolve directly.
825 lookupqueryold(Job *job, Mfile *mf, Request *req, char *errbuf, char *p,
826 int wantsav, int rooted)
833 rp = dnresolve(p, Cin, mf->type, req, 0, 0, Recurse, rooted, &status);
839 status = neg->negrcode;
844 return respond(job, mf, rp, errbuf, status, wantsav);
848 respond(Job *job, Mfile *mf, RR *rp, char *errbuf, int status, int wantsav)
856 return "name does not exist";
858 return "dns failure";
861 snprint(errbuf, ERRMAX,
862 "resource does not exist; negrcode %d", status);
868 /* format data to be read later */
871 for(tp = rp; mf->nrr < Maxrrr-1 && n < Maxreply && tp &&
872 tsame(mf->type, tp->type); tp = tp->next){
873 mf->rr[mf->nrr++] = n;
875 n += snprint(mf->reply+n, Maxreply-n, "%Q", tp);
877 n += snprint(mf->reply+n, Maxreply-n, "%R", tp);
886 /* simulate what dnsudpserver does */
888 lookupquerynew(Job *job, Mfile *mf, Request *req, char *errbuf, char *p,
892 uchar buf[Udphdrsize + Maxudp + 1024];
899 memset(&repmsg, 0, sizeof repmsg);
900 rp = rralloc(mf->type);
901 rp->owner = dnlookup(p, Cin, 1);
902 mp = newdnsmsg(rp, Frecurse|Oquery, (ushort)rand());
904 dnserver(mp, &repmsg, req, buf, Rok);
907 err = respond(job, mf, repmsg.an, errbuf, Rok, wantsav);
908 repmsg.an = nil; /* freed above */
909 freeanswers(&repmsg);
914 rclunk(Job *job, Mfile *mf)
921 rremove(Job *job, Mfile *mf)
924 sendmsg(job, "remove permission denied");
928 rstat(Job *job, Mfile *mf)
931 uchar buf[IOHDRSZ+Maxfdata];
933 memset(&dir, 0, sizeof dir);
934 if(mf->qid.type & QTDIR){
936 dir.mode = DMDIR|0555;
943 dir.uid = dir.gid = dir.muid = mf->user;
944 dir.atime = dir.mtime = time(nil);
945 job->reply.nstat = convD2M(&dir, buf, sizeof buf);
946 job->reply.stat = buf;
951 rwstat(Job *job, Mfile *mf)
954 sendmsg(job, "wstat permission denied");
958 sendmsg(Job *job, char *err)
961 uchar mdata[IOHDRSZ + Maxfdata];
965 job->reply.type = Rerror;
966 snprint(ename, sizeof ename, "dns: %s", err);
967 job->reply.ename = ename;
969 job->reply.type = job->request.type+1;
970 job->reply.tag = job->request.tag;
971 n = convS2M(&job->reply, mdata, sizeof mdata);
973 warning("sendmsg convS2M of %F returns 0", &job->reply);
977 if(job->flushed == 0)
978 if(write(mfd[1], mdata, n)!=n)
979 sysfatal("mount write");
982 dnslog("%F %d", &job->reply, n);
986 * the following varies between dnsdebug and dns
989 logreply(int id, uchar *addr, DNSmsg *mp)
993 dnslog("%d: rcvd %I flags:%s%s%s%s%s", id, addr,
994 mp->flags & Fauth? " auth": "",
995 mp->flags & Ftrunc? " trunc": "",
996 mp->flags & Frecurse? " rd": "",
997 mp->flags & Fcanrec? " ra": "",
998 (mp->flags & (Fauth|Rmask)) == (Fauth|Rname)? " nx": "");
999 for(rp = mp->qd; rp != nil; rp = rp->next)
1000 dnslog("%d: rcvd %I qd %s", id, addr, rp->owner->name);
1001 for(rp = mp->an; rp != nil; rp = rp->next)
1002 dnslog("%d: rcvd %I an %R", id, addr, rp);
1003 for(rp = mp->ns; rp != nil; rp = rp->next)
1004 dnslog("%d: rcvd %I ns %R", id, addr, rp);
1005 for(rp = mp->ar; rp != nil; rp = rp->next)
1006 dnslog("%d: rcvd %I ar %R", id, addr, rp);
1010 logsend(int id, int subid, uchar *addr, char *sname, char *rname, int type)
1014 dnslog("[%d] %d.%d: sending to %I/%s %s %s",
1015 getpid(), id, subid, addr, sname, rname,
1016 rrname(type, buf, sizeof buf));
1020 getdnsservers(int class)
1022 return dnsservers(class);