/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #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 */voiddnnotify(DNSmsg *reqp, DNSmsg *repp, Request *){	RR *tp;	Area *a; 	/* 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; 	dnslog("notification for %s", repp->qd->owner->name); 	/* is it something we care about? */	a = inmyarea(repp->qd->owner->name);	if(a == nil)		return; 	dnslog("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)		a->needrefresh = 1;} /* notify a slave that an area has changed. */static voidsend_notify(char *slave, RR *soa, Request *req){	int i, len, n, reqno, status, fd;	char *err;	uchar ibuf[Maxudp+Udphdrsize], obuf[Maxudp+Udphdrsize];	RR *rp;	Udphdr *up = (Udphdr*)obuf;	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) {		if (parseip(up->raddr, slave) == -1)			dnslog("bad address %s to notify", slave);	} else {		rp = dnresolve(slave, Cin, Ta, req, nil, 0, 1, 1, &status);		if(rp == nil)			rp = dnresolve(slave, Cin, Taaaa, req, nil, 0, 1, 1, &status);		if(rp == nil)			return;		parseip(up->raddr, rp->ip->name);		rrfreelist(rp);		/* was rrfree */	} 	fd = udpport(nil);	if(fd < 0)		return; 	/* send 3 times or until we get anything back */	n += Udphdrsize;	for(i = 0; i < 3; i++, freeanswers(&repmsg)){		dnslog("sending %d byte notify to %s/%I.%d about %s", n, slave,			up->raddr, nhgets(up->rport), soa->owner->name);		memset(&repmsg, 0, sizeof repmsg);		if(write(fd, obuf, n) != n)			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)			break;	}	if (i < 3)		freeanswers(&repmsg);	close(fd);} /* send notifies for any updated areas */static voidnotify_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) */voidnotifyproc(void){	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 */ 	for(;;){		getactivity(&req, 0);		notify_areas(owned, &req);		putactivity(0);		sleep(60*1000);	}}