1 #include <u.h>
2 #include <libc.h>
3 #include <ip.h>
4 #include <bio.h>
5 #include <ndb.h>
6 #include "dns.h"
7 
8 /* get a notification from another system of a changed zone */
9 void
10 dnnotify(DNSmsg *reqp, DNSmsg *repp, Request *r)
11 {
12 	RR *tp;
13 	Area *a;
14 
15 	USED(r);
16 	/* move one question from reqp to repp */
17 	memset(repp, 0, sizeof(*repp));
18 	tp = reqp->qd;
19 	reqp->qd = tp->next;
20 	tp->next = 0;
21 	repp->qd = tp;
22 	repp->id = reqp->id;
23 	repp->flags = Fresp  | Onotify | Fauth;
24 
25 	/* anything to do? */
26 	if(zonerefreshprogram == nil)
27 		return;
28 
29 	/* make sure its the right type */
30 	if(repp->qd->type != Tsoa)
31 		return;
32 
33 syslog(0, logfile, "notification for %s", repp->qd->owner->name);
34 
35 	/* is it something we care about? */
36 	a = inmyarea(repp->qd->owner->name);
37 	if(a == nil)
38 		return;
39 
40 syslog(0, logfile, "serial old %lud new %lud", a->soarr->soa->serial, repp->qd->soa->serial);
41 
42 	/* do nothing if it didn't change */
43 	if(a->soarr->soa->serial== repp->qd->soa->serial)
44 		return;
45 
46 	a->needrefresh = 1;
47 }
48 
49 static void
50 ding(void *u, char *msg)
51 {
52 	USED(u);
53 
54 	if(strstr(msg, "alarm"))
55 		noted(NCONT);
56 	else
57 		noted(NDFLT);
58 }
59 
60 /* notify a slave that an area has changed. */
61 static void
62 send_notify(char *slave, RR *soa, Request *req)
63 {
64 	int i, len, n, reqno, status, fd;
65 	uchar obuf[Maxudp+OUdphdrsize];
66 	uchar ibuf[Maxudp+OUdphdrsize];
67 	RR *rp;
68 	OUdphdr *up = (OUdphdr*)obuf;
69 	char *err;
70 	DNSmsg repmsg;
71 
72 	/* create the request */
73 	reqno = rand();
74 	n = mkreq(soa->owner, Cin, obuf, Fauth | Onotify, reqno);
75 
76 	/* get an address */
77 	if(strcmp(ipattr(slave), "ip") == 0) {
78 		parseip(up->raddr, slave);
79 	} else {
80 		rp = dnresolve(slave, Cin, Ta, req, nil, 0, 1, 1, &status);
81 		if(rp == nil)
82 			return;
83 		parseip(up->raddr, rp->ip->name);
84 		rrfree(rp);
85 	}
86 
87 	fd = udpport();
88 	if(fd < 0)
89 		return;
90 
91 	notify(ding);
92 
93 	/* send 3 times or until we get anything back */
94 	for(i = 0; i < 3; i++){
95 syslog(0, logfile, "sending %d byte notify to %s/%I.%d about %s", n, slave, up->raddr, nhgets(up->rport), soa->owner->name);
96 		if(udpwrite(fd, (OUdphdr*)obuf, obuf+OUdphdrsize, n) != n)
97 			break;
98 		alarm(2*1000);
99 		len = udpread(fd, (Udphdr*)ibuf, ibuf+OUdphdrsize, Maxudp);
100 		alarm(0);
101 		if(len <= OUdphdrsize)
102 			continue;
103 		err = convM2DNS(&ibuf[OUdphdrsize], len, &repmsg);
104 		if(err != nil)
105 			continue;
106 		if(repmsg.id == reqno && (repmsg.flags & Omask) == Onotify)
107 			break;
108 	}
109 
110 	close(fd);
111 }
112 
113 /* send notifies for any updated areas */
114 static void
115 notify_areas(Area *a, Request *req)
116 {
117 	Server *s;
118 
119 	for(; a != nil; a = a->next){
120 		if(!a->neednotify)
121 			continue;
122 
123 		/* send notifies to all slaves */
124 		for(s = a->soarr->soa->slaves; s != nil; s = s->next)
125 			send_notify(s->name, a->soarr, req);
126 		a->neednotify = 0;
127 	}
128 }
129 
130 /*
131  *  process to notify other servers of changes
132  *  (also reads in new databases)
133  */
134 void
135 notifyproc(void)
136 {
137 	Request req;
138 	static int already;
139 
140 	if(already)
141 		return;
142 
143 	switch(rfork(RFPROC|RFNOTEG|RFMEM|RFNOWAIT)){
144 	case -1:
145 		return;
146 	case 0:
147 		break;
148 	default:
149 		return;
150 	}
151 
152 	req.isslave = 1;	/* son't fork off subprocesses */
153 
154 	for(;;){
155 		getactivity(&req);
156 		notify_areas(owned, &req);
157 		putactivity();
158 		sleep(60*1000);
159 	}
160 }