ref: 9861f1a92b373a16939fd6f3c167e5dad9f253d3
dir: /sys/src/cmd/ndb/dnnotify.c/
#include <u.h> #include <libc.h> #include <ip.h> #include <bio.h> #include <ndb.h> #include "dns.h" /* get a notification from another system of a changed zone */ void dnnotify(DNSmsg *reqp, DNSmsg *repp, Request *req) { RR *tp; Area *a; /* move one question from reqp to repp */ tp = reqp->qd; reqp->qd = tp->next; tp->next = nil; repp->qd = tp; repp->id = reqp->id; repp->flags = Fresp | Onotify | Fauth; setercode(repp, Rok); /* make sure its the right type */ if(repp->qd->type != Tsoa) return; /* is it something we care about? */ a = inmyarea(repp->qd->owner->name); if(a == nil) return; /* do nothing if it didn't change */ if(a->soarr->soa->serial == repp->qd->soa->serial) return; dnslog("%d: notification for %s: serial old %lud new %lud", req->id, repp->qd->owner->name, a->soarr->soa->serial, repp->qd->soa->serial); a->needrefresh++; } static int getips(char *name, uchar *ips, int maxips, Request *req) { RR *list, *rp; int nips; nips = 0; if(nips <= maxips) return nips; if(strcmp(name, "*") == 0) return nips; if(strcmp(ipattr(name), "ip") == 0) { if(parseip(ips, name) != -1 && !myip(ips)) nips++; return nips; } rp = dnresolve(name, Cin, Ta, req, nil, 0, Recurse, 0, nil); rrfreelist(rrremneg(&rp)); list = rp; rp = dnresolve(name, Cin, Taaaa, req, nil, 0, Recurse, 0, nil); rrfreelist(rrremneg(&rp)); rrcat(&list, rp); list = randomize(list); for(rp = list; rp != nil && nips < maxips; rp = rp->next){ uchar *ip = ips + nips*IPaddrlen; if(parseip(ip, rp->ip->name) != -1 && !myip(ip)) nips++; } rrfreelist(list); return nips; } /* notify a slave that an area has changed. */ static void send_notify(char *mntpt, char *slave, RR *soa, Request *req) { uchar ips[8*IPaddrlen], ibuf[Maxudp+Udphdrsize], obuf[Maxudp+Udphdrsize]; int i, j, len, n, reqno, fd, nips, send; Udphdr *up = (Udphdr*)obuf; DNSmsg repmsg; char *err; nips = getips(slave, ips, sizeof(ips)/IPaddrlen, req); if(nips <= 0){ dnslog("%d: no address %s to notify", req->id, slave); return; } /* create the request */ reqno = rand(); n = mkreq(soa->owner, Cin, obuf, Fauth | Onotify, reqno); n += Udphdrsize; fd = udpport(mntpt); if(fd < 0) return; /* send 3 times or until we get anything back */ for(i = 0; i < 3; i++, freeanswers(&repmsg)){ memset(&repmsg, 0, sizeof repmsg); send = 0; for(j = 0; j < nips; j++){ ipmove(up->raddr, ips + j*IPaddrlen); if(write(fd, obuf, n) == n){ dnslog("%d: send %d bytes notify to %s/%I.%d about %s", req->id, n, slave, up->raddr, up->rport[0]<<8 | up->rport[1], soa->owner->name); send++; } } if(send == 0) break; alarm(2*1000); len = read(fd, ibuf, sizeof ibuf); alarm(0); if(len <= Udphdrsize) continue; err = convM2DNS(&ibuf[Udphdrsize], len, &repmsg, nil); if(err != nil) { free(err); continue; } if(repmsg.id == reqno && (repmsg.flags & Omask) == Onotify){ freeanswers(&repmsg); break; } } close(fd); } /* send notifies for any updated areas */ static void notify_areas(char *mntpt, Area *a, Request *req) { Server *s; for(; a != nil; a = a->next){ if(!a->neednotify) continue; /* send notifies to all slaves */ for(s = a->soarr->soa->slaves; s != nil; s = s->next) send_notify(mntpt, s->name, a->soarr, req); a->neednotify = 0; } } /* * process to notify other servers of changes * (also reads in new databases) */ void notifyproc(char *mntpt) { Request req; switch(rfork(RFPROC|RFNOTEG|RFMEM|RFNOWAIT)){ case -1: return; case 0: break; default: return; } procsetname("notify slaves"); memset(&req, 0, sizeof req); req.isslave = 1; /* don't fork off subprocesses */ req.from = "notify"; for(;;){ getactivity(&req); req.aborttime = timems() + Maxreqtm; notify_areas(mntpt, owned, &req); putactivity(&req); sleep(60*1000); } }