add dns

1 files changed, 362 insertions, 0 deletions

diff --git a/src/cmd/ndb/dnstcp.c b/src/cmd/ndb/dnstcp.c
new file mode 100755
index 00000000..19a7540d
--- /dev/null
+++ b/src/cmd/ndb/dnstcp.c
@@ -0,0 +1,362 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include "dns.h"
+
+enum
+{
+	Maxpath=		128,
+};
+
+char	*logfile = "dns";
+char	*dbfile;
+int	debug;
+int	cachedb = 1;
+int	testing;
+int traceactivity;
+int	needrefresh;
+int 	resolver;
+char	mntpt[Maxpath];
+char	*caller = "";
+ulong	now;
+int	maxage;
+uchar	ipaddr[IPaddrlen];	/* my ip address */
+char	*LOG;
+char	*zonerefreshprogram;
+
+static int	readmsg(int, uchar*, int);
+static void	reply(int, DNSmsg*, Request*);
+static void	dnzone(DNSmsg*, DNSmsg*, Request*);
+static void	getcaller(char*);
+static void	refreshmain(char*);
+
+void
+main(int argc, char *argv[])
+{
+	int len;
+	Request req;
+	DNSmsg reqmsg, repmsg;
+	uchar buf[512];
+	char tname[32];
+	char *err;
+	char *ext = "";
+
+	ARGBEGIN{
+	case 'd':
+		debug++;
+		break;
+	case 'f':
+		dbfile = ARGF();
+		break;
+	case 'r':
+		resolver = 1;
+		break;
+	case 'x':
+		ext = ARGF();
+		break;
+	}ARGEND
+
+	if(debug < 2)
+		debug = 0;
+
+	if(argc > 0)
+		getcaller(argv[0]);
+
+	dninit();
+
+	snprint(mntpt, sizeof(mntpt), "/net%s", ext);
+	if(myipaddr(ipaddr, mntpt) < 0)
+		sysfatal("can't read my ip address");
+	syslog(0, logfile, "dnstcp call from %s to %I", caller, ipaddr);
+
+	db2cache(1);
+
+	setjmp(req.mret);
+	req.isslave = 0;
+
+	/* loop on requests */
+	for(;; putactivity()){
+		now = time(0);
+		memset(&repmsg, 0, sizeof(repmsg));
+		alarm(10*60*1000);
+		len = readmsg(0, buf, sizeof(buf));
+		alarm(0);
+		if(len <= 0)
+			break;
+		getactivity(&req);
+		req.aborttime = now + 15*Min;
+		err = convM2DNS(buf, len, &reqmsg);
+		if(err){
+			syslog(0, logfile, "server: input error: %s from %I", err, buf);
+			break;
+		}
+		if(reqmsg.qdcount < 1){
+			syslog(0, logfile, "server: no questions from %I", buf);
+			break;
+		}
+		if(reqmsg.flags & Fresp){
+			syslog(0, logfile, "server: reply not request from %I", buf);
+			break;
+		}
+		if((reqmsg.flags & Omask) != Oquery){
+			syslog(0, logfile, "server: op %d from %I", reqmsg.flags & Omask, buf);
+			break;
+		}
+
+		if(debug)
+			syslog(0, logfile, "%d: serve (%s) %d %s %s",
+				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);
+				reply(1, &repmsg, &req);
+				rrfreelist(repmsg.qd);
+				rrfreelist(repmsg.an);
+				rrfreelist(repmsg.ns);
+				rrfreelist(repmsg.ar);
+			}
+		}
+
+		rrfreelist(reqmsg.qd);
+		rrfreelist(reqmsg.an);
+		rrfreelist(reqmsg.ns);
+		rrfreelist(reqmsg.ar);
+
+		if(req.isslave){
+			putactivity();
+			_exits(0);
+		}
+	}
+	refreshmain(mntpt);
+}
+
+static int
+readmsg(int fd, uchar *buf, int max)
+{
+	int n;
+	uchar x[2];
+
+	if(readn(fd, x, 2) != 2)
+		return -1;
+	n = (x[0]<<8) | x[1];
+	if(n > max)
+		return -1;
+	if(readn(fd, buf, n) != n)
+		return -1;
+	return n;
+}
+
+static void
+reply(int fd, DNSmsg *rep, Request *req)
+{
+	int len, rv;
+	char tname[32];
+	uchar buf[4096];
+	RR *rp;
+
+	if(debug){
+		syslog(0, logfile, "%d: reply (%s) %s %s %ux",
+			req->id, caller,
+			rep->qd->owner->name,
+			rrname(rep->qd->type, tname, sizeof tname),
+			rep->flags);
+		for(rp = rep->an; rp; rp = rp->next)
+			syslog(0, logfile, "an %R", rp);
+		for(rp = rep->ns; rp; rp = rp->next)
+			syslog(0, logfile, "ns %R", rp);
+		for(rp = rep->ar; rp; rp = rp->next)
+			syslog(0, logfile, "ar %R", rp);
+	}
+
+
+	len = convDNS2M(rep, buf+2, sizeof(buf) - 2);
+	if(len <= 0)
+		abort(); /* "dnserver: converting reply" */;
+	buf[0] = len>>8;
+	buf[1] = len;
+	rv = write(fd, buf, len+2);
+	if(rv != len+2){
+		syslog(0, logfile, "sending reply: %d instead of %d", rv, len+2);
+		exits(0);
+	}
+}
+
+/*
+ *  Hash table for domain names.  The hash is based only on the
+ *  first element of the domain name.
+ */
+extern DN	*ht[HTLEN];
+
+static int
+numelem(char *name)
+{
+	int i;
+
+	i = 1;
+	for(; *name; name++)
+		if(*name == '.')
+			i++;
+	return i;
+}
+
+int
+inzone(DN *dp, char *name, int namelen, int depth)
+{
+	int n;
+
+	if(dp->name == 0)
+		return 0;
+	if(numelem(dp->name) != depth)
+		return 0;
+	n = strlen(dp->name);
+	if(n < namelen)
+		return 0;
+	if(strcmp(name, dp->name + n - namelen) != 0)
+		return 0;
+	if(n > namelen && dp->name[n - namelen - 1] != '.')
+		return 0;
+	return 1;
+}
+
+static void
+dnzone(DNSmsg *reqp, DNSmsg *repp, Request *req)
+{
+	DN *dp, *ndp;
+	RR r, *rp;
+	int h, depth, found, nlen;
+
+	memset(repp, 0, sizeof(*repp));
+	repp->id = reqp->id;
+	repp->flags = Fauth | Fresp | Fcanrec | Oquery;
+	repp->qd = reqp->qd;
+	reqp->qd = reqp->qd->next;
+	repp->qd->next = 0;
+	dp = repp->qd->owner;
+
+	/* send the soa */
+	repp->an = rrlookup(dp, Tsoa, NOneg);
+	reply(1, repp, req);
+	if(repp->an == 0)
+		goto out;
+	rrfreelist(repp->an);
+
+	nlen = strlen(dp->name);
+
+	/* construct a breadth first search of the name space (hard with a hash) */
+	repp->an = &r;
+	for(depth = numelem(dp->name); ; depth++){
+		found = 0;
+		for(h = 0; h < HTLEN; h++)
+			for(ndp = ht[h]; ndp; ndp = ndp->next)
+				if(inzone(ndp, dp->name, nlen, depth)){
+					for(rp = ndp->rr; rp; rp = rp->next){
+						/* there shouldn't be negatives, but just in case */
+						if(rp->negative)
+							continue;
+
+						/* don't send an soa's, ns's are enough */
+						if(rp->type == Tsoa)
+							continue;
+
+						r = *rp;
+						r.next = 0;
+						reply(1, repp, req);
+					}
+					found = 1;
+				}
+		if(!found)
+			break;
+	}
+
+	/* resend the soa */
+	repp->an = rrlookup(dp, Tsoa, NOneg);
+	reply(1, repp, req);
+	rrfreelist(repp->an);
+out:
+	rrfree(repp->qd);
+}
+
+static void
+getcaller(char *dir)
+{
+	int fd, n;
+	static char remote[128];
+
+	snprint(remote, sizeof(remote), "%s/remote", dir);
+	fd = open(remote, OREAD);
+	if(fd < 0)
+		return;
+	n = read(fd, remote, sizeof(remote)-1);
+	close(fd);
+	if(n <= 0)
+		return;
+	if(remote[n-1] == '\n')
+		n--;
+	remote[n] = 0;
+	caller = remote;
+}
+
+static void
+refreshmain(char *net)
+{
+	int fd;
+	char file[128];
+
+	snprint(file, sizeof(file), "%s/dns", net);
+	if(debug)
+		syslog(0, logfile, "refreshing %s", file);
+	fd = open(file, ORDWR);
+	if(fd < 0){
+		syslog(0, logfile, "can't refresh %s", file);
+		return;
+	}
+	fprint(fd, "refresh");
+	close(fd);
+}
+
+/*
+ *  the following varies between dnsdebug and dns
+ */
+void
+logreply(int id, uchar *addr, DNSmsg *mp)
+{
+	RR *rp;
+
+	syslog(0, LOG, "%d: rcvd %I flags:%s%s%s%s%s", id, addr,
+		mp->flags & Fauth ? " auth" : "",
+		mp->flags & Ftrunc ? " trunc" : "",
+		mp->flags & Frecurse ? " rd" : "",
+		mp->flags & Fcanrec ? " ra" : "",
+		mp->flags & (Fauth|Rname) == (Fauth|Rname) ?
+		" nx" : "");
+	for(rp = mp->qd; rp != nil; rp = rp->next)
+		syslog(0, LOG, "%d: rcvd %I qd %s", id, addr, rp->owner->name);
+	for(rp = mp->an; rp != nil; rp = rp->next)
+		syslog(0, LOG, "%d: rcvd %I an %R", id, addr, rp);
+	for(rp = mp->ns; rp != nil; rp = rp->next)
+		syslog(0, LOG, "%d: rcvd %I ns %R", id, addr, rp);
+	for(rp = mp->ar; rp != nil; rp = rp->next)
+		syslog(0, LOG, "%d: rcvd %I ar %R", id, addr, rp);
+}
+
+void
+logsend(int id, int subid, uchar *addr, char *sname, char *rname, int type)
+{
+	char buf[12];
+
+	syslog(0, LOG, "%d.%d: sending to %I/%s %s %s",
+		id, subid, addr, sname, rname, rrname(type, buf, sizeof buf));
+}
+
+RR*
+getdnsservers(int class)
+{
+	return dnsservers(class);
+}