void
main(int argc, char *argv[])
{
int kid, pid;
char servefile[Maxpath], ext[Maxpath];
Dir *dir;
setnetmtpt(mntpt, sizeof mntpt, nil);
ext[0] = 0;
ARGBEGIN{
case 'a':
maxage = atol(EARGF(usage()));
if (maxage <= 0)
maxage = Defmaxage;
break;
case 'd':
debug = 1;
traceactivity = 1;
break;
case 'f':
dbfile = EARGF(usage());
break;
case 'F':
cfg.justforw = cfg.resolver = 1;
break;
case 'n':
sendnotifies = 1;
break;
case 'N':
target = atol(EARGF(usage()));
if (target < 1000)
target = 1000;
break;
case 'o':
cfg.straddle = 1; /* straddle inside & outside networks */
break;
case 'r':
cfg.resolver = 1;
break;
case 'R':
norecursion = 1;
break;
case 's':
cfg.serve = 1; /* serve network */
cfg.cachedb = 1;
break;
case 't':
testing = 1;
break;
case 'T':
addforwtarg(EARGF(usage()));
break;
case 'x':
setnetmtpt(mntpt, sizeof mntpt, EARGF(usage()));
setext(ext, sizeof ext, mntpt);
break;
case 'z':
zonerefreshprogram = EARGF(usage());
break;
default:
usage();
break;
}ARGEND
if(argc != 0)
usage();
if(testing)
mainmem->flags |= POOL_NOREUSE | POOL_ANTAGONISM;
mainmem->flags |= POOL_ANTAGONISM;
rfork(RFREND|RFNOTEG);
cfg.inside = (*mntpt == '\0' || strcmp(mntpt, "/net") == 0);
/* start syslog before we fork */
fmtinstall('F', fcallfmt);
dninit();
/* this really shouldn't be fatal */
if(myipaddr(ipaddr, mntpt) < 0)
sysfatal("can't read my ip address");
dnslog("starting %s%sdns %s%s%son %I's %s",
(cfg.straddle? "straddling ": ""),
(cfg.cachedb? "caching ": ""),
(cfg.serve? "udp server ": ""),
(cfg.justforw? "forwarding-only ": ""),
(cfg.resolver? "resolver ": ""), ipaddr, mntpt);
opendatabase();
now = time(nil); /* open time files before we fork */
nowns = nsec();
snprint(servefile, sizeof servefile, "#s/dns%s", ext);
dir = dirstat(servefile);
if (dir)
sysfatal("%s exists; another dns instance is running",
servefile);
free(dir);
/* don't unmount here; could deadlock */
// while (unmount(servefile, mntpt) >= 0)
// ;
mountinit(servefile, mntpt); /* forks, parent exits */
srand(now*getpid());
db2cache(1);
// dnageallnever();
if (cfg.straddle && !seerootns())
dnslog("straddle server misconfigured; can't resolve root name servers");
/*
* fork without sharing heap.
* parent waits around for child to die, then forks & restarts.
* child may spawn udp server, notify procs, etc.; when it gets too
* big or too old, it kills itself and any children.
*
* /srv/dns remains open and valid, but /net/dns was only mounted in
* a child's separate namespace from 9p service, to avoid a deadlock
* from serving our own namespace, so we must remount it upon restart,
* in a separate process and namespace.
*/
for (;;) {
start = time(nil);
/* don't unmount here; could deadlock */
// unmount(servefile, mntpt);
kid = rfork(RFPROC|RFFDG|RFNOTEG|RFNAMEG);
switch (kid) {
case -1:
sysfatal("fork failed: %r");
case 0:
if(cfg.serve)
dnudpserver(mntpt);
if(sendnotifies)
notifyproc();
io(); /* serve 9p; return implies restart */
_exits("restart");
}
sleep(1000); /* wait for 9p service to start */
justremount(servefile, mntpt);
while ((pid = waitpid()) != kid && pid != -1)
continue;
dnslog("restarting");
}
}
void
main(int argc, char *argv[])
{
int len, rcode;
char tname[32];
char *err, *ext = "";
unsigned char buf[64*1024], callip[IPaddrlen];
DNSmsg reqmsg, repmsg;
Request req;
alarm(2*60*1000);
cfg.cachedb = 1;
ARGBEGIN{
case 'd':
debug++;
break;
case 'f':
dbfile = EARGF(usage());
break;
case 'r':
cfg.resolver = 1;
break;
case 'R':
norecursion = 1;
break;
case 'x':
ext = EARGF(usage());
break;
default:
usage();
break;
}ARGEND
if(debug < 2)
debug = 0;
if(argc > 0)
getcaller(argv[0]);
cfg.inside = 1;
dninit();
snprint(mntpt, sizeof mntpt, "/net%s", ext);
if(myipaddr(ipaddr, mntpt) < 0)
sysfatal("can't read my ip address");
dnslog("dnstcp call from %s to %I", caller, ipaddr);
memset(callip, 0, sizeof callip);
parseip(callip, caller);
db2cache(1);
memset(&req, 0, sizeof req);
setjmp(req.mret);
req.isslave = 0;
procsetname("main loop");
/* loop on requests */
for(;; putactivity(0)){
now = time(nil);
memset(&repmsg, 0, sizeof repmsg);
len = readmsg(0, buf, sizeof buf);
if(len <= 0)
break;
getactivity(&req, 0);
req.aborttime = timems() + S2MS(15*Min);
rcode = 0;
memset(&reqmsg, 0, sizeof reqmsg);
err = convM2DNS(buf, len, &reqmsg, &rcode);
if(err){
dnslog("server: input error: %s from %s", err, caller);
free(err);
break;
}
if (rcode == 0) {
if(reqmsg.qdcount < 1){
dnslog("server: no questions from %s", caller);
break;
} else if(reqmsg.flags & Fresp){
dnslog("server: reply not request from %s",
caller);
break;
} else if((reqmsg.flags & Omask) != Oquery){
dnslog("server: op %d from %s",
reqmsg.flags & Omask, caller);
break;
}
}
if(debug)
dnslog("[%d] %d: serve (%s) %d %s %s",
getpid(), req.id, caller,
reqmsg.id, reqmsg.qd->owner->name,
rrname(reqmsg.qd->type, tname, sizeof tname));
/* loop through each question */
while(reqmsg.qd)
if(reqmsg.qd->type == Taxfr)
dnzone(&reqmsg, &repmsg, &req);
else {
dnserver(&reqmsg, &repmsg, &req, callip, rcode);
reply(1, &repmsg, &req);
rrfreelist(repmsg.qd);
rrfreelist(repmsg.an);
rrfreelist(repmsg.ns);
rrfreelist(repmsg.ar);
}
rrfreelist(reqmsg.qd); /* qd will be nil */
rrfreelist(reqmsg.an);
rrfreelist(reqmsg.ns);
rrfreelist(reqmsg.ar);
if(req.isslave){
putactivity(0);
_exits(0);
}
}
refreshmain(mntpt);
}
void
threadmain(int argc, char *argv[])
{
int serveudp, servetcp;
char *service;
serveudp = 0;
servetcp = 0;
service = "dns";
ARGBEGIN{
case 'd':
debug = 1;
traceactivity = 1;
break;
case 'f':
dbfile = EARGF(usage());
break;
case 'x':
service = EARGF(usage());
break;
case 'r':
resolver = 1;
break;
case 's':
serveudp = 1;
cachedb = 1;
break;
case 't':
servetcp = 1;
cachedb = 1;
break;
case 'a':
maxage = atoi(EARGF(usage()));
break;
case 'z':
zonerefreshprogram = EARGF(usage());
break;
case 'n':
sendnotifies = 1;
break;
case 'U':
udpaddr = estrdup(netmkaddr(EARGF(usage()), "udp", "domain"));
break;
case 'T':
tcpaddr = estrdup(netmkaddr(EARGF(usage()), "tcp", "domain"));
break;
default:
usage();
}ARGEND
if(argc)
usage();
if(serveudp && servetcp)
checkaddress();
rfork(RFNOTEG);
/* start syslog before we fork */
fmtinstall('F', fcallfmt);
dninit();
if(myipaddr(ipaddr, mntpt) < 0)
sysfatal("can't read my ip address");
syslog(0, logfile, "starting dns on %I", ipaddr);
opendatabase();
mountinit(service);
now = time(0);
srand(now*getpid());
db2cache(1);
if(serveudp)
proccreate(dnudpserver, nil, STACK);
if(servetcp)
proccreate(dntcpserver, nil, STACK);
if(sendnotifies)
proccreate(notifyproc, nil, STACK);
io();
}