add dns

src/cmd/ndb/dnnotify.c

@@ -0,0 +1,160 @@
+#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 *r)
+{
+	RR *tp;
+	Area *a;
+
+	USED(r);
+	/* move one question from reqp to repp */
+	memset(repp, 0, sizeof(*repp));
+	tp = reqp->qd;
+	reqp->qd = tp->next;
+	tp->next = 0;
+	repp->qd = tp;
+	repp->id = reqp->id;
+	repp->flags = Fresp  | Onotify | Fauth;
+
+	/* anything to do? */
+	if(zonerefreshprogram == nil)
+		return;
+
+	/* make sure its the right type */
+	if(repp->qd->type != Tsoa)
+		return;
+
+syslog(0, logfile, "notification for %s", repp->qd->owner->name);
+
+	/* is it something we care about? */
+	a = inmyarea(repp->qd->owner->name);
+	if(a == nil)
+		return;
+
+syslog(0, logfile, "serial old %lud new %lud", a->soarr->soa->serial, repp->qd->soa->serial);
+
+	/* do nothing if it didn't change */
+	if(a->soarr->soa->serial== repp->qd->soa->serial)
+		return;
+
+	a->needrefresh = 1;
+}
+
+static void
+ding(void *u, char *msg)
+{
+	USED(u);
+
+	if(strstr(msg, "alarm"))
+		noted(NCONT);
+	else
+		noted(NDFLT);
+}
+
+/* notify a slave that an area has changed. */
+static void
+send_notify(char *slave, RR *soa, Request *req)
+{
+	int i, len, n, reqno, status, fd;
+	uchar obuf[Maxudp+OUdphdrsize];
+	uchar ibuf[Maxudp+OUdphdrsize];
+	RR *rp;
+	OUdphdr *up = (OUdphdr*)obuf;
+	char *err;
+	DNSmsg repmsg;
+
+	/* create the request */
+	reqno = rand();
+	n = mkreq(soa->owner, Cin, obuf, Fauth | Onotify, reqno);
+
+	/* get an address */
+	if(strcmp(ipattr(slave), "ip") == 0) {
+		parseip(up->raddr, slave);
+	} else {
+		rp = dnresolve(slave, Cin, Ta, req, nil, 0, 1, 1, &status);
+		if(rp == nil)
+			return;
+		parseip(up->raddr, rp->ip->name);
+		rrfree(rp);
+	}
+
+	fd = udpport();
+	if(fd < 0)
+		return;
+
+	notify(ding);
+
+	/* send 3 times or until we get anything back */
+	for(i = 0; i < 3; i++){
+syslog(0, logfile, "sending %d byte notify to %s/%I.%d about %s", n, slave, up->raddr, nhgets(up->rport), soa->owner->name);
+		if(udpwrite(fd, (OUdphdr*)obuf, obuf+OUdphdrsize, n) != n)
+			break;
+		alarm(2*1000);
+		len = udpread(fd, (Udphdr*)ibuf, ibuf+OUdphdrsize, Maxudp);
+		alarm(0);
+		if(len <= OUdphdrsize)
+			continue;
+		err = convM2DNS(&ibuf[OUdphdrsize], len, &repmsg);
+		if(err != nil)
+			continue;
+		if(repmsg.id == reqno && (repmsg.flags & Omask) == Onotify)
+			break;
+	}
+
+	close(fd);
+}
+
+/* send notifies for any updated areas */
+static void
+notify_areas(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(s->name, a->soarr, req);
+		a->neednotify = 0;
+	}
+}
+
+/*
+ *  process to notify other servers of changes
+ *  (also reads in new databases)
+ */
+void
+notifyproc(void)
+{
+	Request req;
+	static int already;
+
+	if(already)
+		return;
+
+	switch(rfork(RFPROC|RFNOTEG|RFMEM|RFNOWAIT)){
+	case -1:
+		return;
+	case 0:
+		break;
+	default:
+		return;
+	}
+
+	req.isslave = 1;	/* son't fork off subprocesses */
+
+	for(;;){
+		getactivity(&req);
+		notify_areas(owned, &req);
+		putactivity();
+		sleep(60*1000);
+	}
+}