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