10 static int udpannounce(char*);
11 static void reply(int, uchar*, DNSmsg*, Request*);
13 typedef struct Inprogress Inprogress;
22 Inprogress inprog[Maxactive+2];
24 typedef struct Forwtarg Forwtarg;
27 uchar addr[IPaddrlen];
31 Forwtarg forwtarg[10];
34 static char *hmsg = "headers";
37 * record client id and ignore retransmissions.
38 * we're still single thread at this point.
41 clientrxmit(DNSmsg *req, uchar *buf)
43 Inprogress *p, *empty;
48 for(p = inprog; p < &inprog[Maxactive]; p++){
55 if(req->qd->owner == p->owner)
56 if(req->qd->type == p->type)
57 if(memcmp(uh, &p->uh, Udphdrsize) == 0)
61 return nil; /* shouldn't happen: see slave() & Maxactive def'n */
64 empty->owner = req->qd->owner;
65 empty->type = req->qd->type;
66 if (empty->type != req->qd->type)
67 dnslog("clientrxmit: bogus req->qd->type %d", req->qd->type);
68 memmove(&empty->uh, uh, Udphdrsize);
74 addforwtarg(char *host)
78 if (forwtcount >= nelem(forwtarg)) {
79 dnslog("too many forwarding targets");
82 tp = forwtarg + forwtcount;
83 if (parseip(tp->addr, host) < 0) {
84 dnslog("can't parse ip %s", host);
87 tp->lastdial = time(nil);
88 tp->fd = udpport(mntpt);
93 tp->host = estrdup(host);
99 * fast forwarding of incoming queries to other dns servers.
100 * intended primarily for debugging.
103 redistrib(uchar *buf, int len)
105 uchar save[Udphdrsize];
109 memmove(save, buf, Udphdrsize);
112 for (tp = forwtarg; tp < forwtarg + forwtcount; tp++)
114 memmove(uh->raddr, tp->addr, sizeof tp->addr);
115 hnputs(uh->rport, 53); /* dns port */
116 if (write(tp->fd, buf, len) != len) {
120 } else if (tp->host && time(nil) - tp->lastdial > 60) {
121 tp->lastdial = time(nil);
122 tp->fd = udpport(mntpt);
125 memmove(buf, save, Udphdrsize);
129 * a process to act as a dns server for outside reqeusts
132 dnudpserver(char *mntpt)
134 volatile int fd, len, op, rcode;
136 volatile char tname[32];
137 volatile uchar buf[Udphdrsize + Maxudp + 1024];
138 volatile DNSmsg reqmsg, repmsg;
139 Inprogress *volatile p;
140 volatile Request req;
144 * fork sharing text, data, and bss with parent.
145 * stay in the same note group.
147 switch(rfork(RFPROC|RFMEM|RFNOWAIT)){
158 procsetname("udp server announcing");
161 while((fd = udpannounce(mntpt)) < 0)
164 // procsetname("udp server");
165 memset(&req, 0, sizeof req);
172 /* loop on requests */
173 for(;; putactivity(0)){
174 procsetname("served %d udp; %d alarms",
175 stats.qrecvdudp, stats.alarms);
176 memset(&repmsg, 0, sizeof repmsg);
177 memset(&reqmsg, 0, sizeof reqmsg);
180 len = read(fd, buf, sizeof buf);
182 if(len <= Udphdrsize)
191 // dnslog("read received UDP from %I to %I",
192 // ((Udphdr*)buf)->raddr, ((Udphdr*)buf)->laddr);
193 getactivity(&req, 0);
194 req.aborttime = timems() + Maxreqtm;
195 req.from = smprint("%I", buf);
199 err = convM2DNS(&buf[Udphdrsize], len, &reqmsg, &rcode);
201 /* first bytes in buf are source IP addr */
202 dnslog("server: input error: %s from %I", err, buf);
207 if(reqmsg.qdcount < 1){
208 dnslog("server: no questions from %I", buf);
210 } else if(reqmsg.flags & Fresp){
211 dnslog("server: reply not request from %I", buf);
214 op = reqmsg.flags & Omask;
215 if(op != Oquery && op != Onotify){
216 dnslog("server: op %d from %I", reqmsg.flags & Omask,
221 if(reqmsg.qd == nil){
222 dnslog("server: no question RR from %I", buf);
226 if(debug || (trace && subsume(trace, reqmsg.qd->owner->name)))
227 dnslog("%d: serve (%I/%d) %d %s %s",
228 req.id, buf, uh->rport[0]<<8 | uh->rport[1],
229 reqmsg.id, reqmsg.qd->owner->name,
230 rrname(reqmsg.qd->type, tname, sizeof tname));
232 p = clientrxmit(&reqmsg, buf);
235 dnslog("%d: duplicate", req.id);
242 for (rr = reqmsg.qd; rr; rr = rr->next)
243 syslog(0, "dnsq", "id %d: (%I/%d) %d %s %s",
244 req.id, buf, uh->rport[0]<<8 |
245 uh->rport[1], reqmsg.id,
246 reqmsg.qd->owner->name,
247 rrname(reqmsg.qd->type, tname,
250 /* loop through each question */
252 memset(&repmsg, 0, sizeof repmsg);
255 dnserver(&reqmsg, &repmsg, &req, buf, rcode);
258 dnnotify(&reqmsg, &repmsg, &req);
261 /* send reply on fd to address in buf's udp hdr */
262 reply(fd, buf, &repmsg, &req);
263 freeanswers(&repmsg);
270 freeanswers(&reqmsg);
279 * announce on well-known dns udp port and set message style interface
282 udpannounce(char *mntpt)
285 char dir[64], datafile[64+6];
289 sprint(datafile, "%s/udp!*!dns", mntpt);
290 ctl = announce(datafile, dir);
293 warning("can't announce on %s", datafile);
297 /* turn on header style interface */
298 if(write(ctl, hmsg, strlen(hmsg)) != strlen(hmsg)){
301 warning("can't enable headers on %s", datafile);
305 snprint(datafile, sizeof(datafile), "%s/data", dir);
306 data = open(datafile, ORDWR);
310 warning("can't open %s to announce on dns udp port",
320 reply(int fd, uchar *buf, DNSmsg *rep, Request *reqp)
325 if(debug || (trace && subsume(trace, rep->qd->owner->name)))
326 dnslog("%d: reply (%I/%d) %d %s %s qd %R an %R ns %R ar %R",
327 reqp->id, buf, buf[4]<<8 | buf[5],
328 rep->id, rep->qd->owner->name,
329 rrname(rep->qd->type, tname, sizeof tname),
330 rep->qd, rep->an, rep->ns, rep->ar);
332 len = convDNS2M(rep, &buf[Udphdrsize], Maxudp);
334 if(write(fd, buf, len) != len)
335 dnslog("error sending reply: %r");