forgot

1 files changed, 294 insertions, 0 deletions

diff --git a/src/cmd/ndb/dntcpserver.c b/src/cmd/ndb/dntcpserver.c
new file mode 100644
index 00000000..4ae787a8
--- /dev/null
+++ b/src/cmd/ndb/dntcpserver.c
@@ -0,0 +1,294 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include <bio.h>
+#include <ndb.h>
+#include <thread.h>
+#include "dns.h"
+
+static char adir[40];
+
+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 int
+connreadmsg(int tfd, int *fd, uchar *buf, int max)
+{
+	int n;
+	int lfd;
+	char ldir[40];
+
+	lfd = listen(adir, ldir);
+	if (lfd < 0)
+		return -1;
+	*fd = accept(lfd, ldir);
+	n = -1;
+	if (*fd < 0)
+		n = readmsg(*fd, buf, max);
+	//close(fd);
+	close(lfd);
+	return n;
+}
+
+static int
+reply(int fd, DNSmsg *rep, Request *req, NetConnInfo *caller)
+{
+	int len;
+	char tname[32];
+	uchar buf[4096];
+	RR *rp;
+
+	if(debug){
+		syslog(0, logfile, "%d: reply (%s) %s %s %ux",
+			req->id, caller ? caller->raddr : "unk",
+			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;
+	if(write(fd, buf, len+2) < 0){
+		syslog(0, logfile, "sending reply: %r");
+		return -1;
+	}
+	return 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;
+}
+
+static 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 int
+dnzone(DNSmsg *reqp, DNSmsg *repp, Request *req, int rfd, NetConnInfo *caller)
+{
+	DN *dp, *ndp;
+	RR r, *rp;
+	int h, depth, found, nlen, rv;
+
+	rv = 0;
+	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);
+	rv = reply(rfd, repp, req, caller);
+	if(repp->an == 0 || rv < 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;
+						rv = reply(rfd, repp, req, caller);
+						if(rv < 0)
+							goto out;
+					}
+					found = 1;
+				}
+		if(!found)
+			break;
+	}
+
+	/* resend the soa */
+	repp->an = rrlookup(dp, Tsoa, NOneg);
+	rv = reply(rfd, repp, req, caller);
+out:
+	if (repp->an)
+		rrfreelist(repp->an);
+	rrfree(repp->qd);
+	return rv;
+}
+
+void
+tcpproc(void *v)
+{
+	int len;
+	Request req;
+	DNSmsg reqmsg, repmsg;
+	char *err;
+	uchar buf[512];
+	char tname[32];
+	int fd, rfd;
+	NetConnInfo *caller;
+
+	rfd = -1;
+	fd = (int)v;
+	caller = 0;
+	/* loop on requests */
+	for(;; putactivity()){
+		if (rfd == 1)
+			return;
+		close(rfd);
+		now = time(0);
+		memset(&repmsg, 0, sizeof(repmsg));
+		freenetconninfo(caller);
+		caller = getnetconninfo(0, fd);
+		if (fd == 0) {
+			len = readmsg(fd, buf, sizeof buf);
+			rfd = 1;
+		} else {
+			len = connreadmsg(fd, &rfd, buf, sizeof buf);
+		}
+		if(len <= 0)
+			continue;
+		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);
+			continue;
+		}
+		if(reqmsg.qdcount < 1){
+			syslog(0, logfile, "server: no questions from %I", buf);
+			continue;
+		}
+		if(reqmsg.flags & Fresp){
+			syslog(0, logfile, "server: reply not request from %I", buf);
+			continue;
+		}
+		if((reqmsg.flags & Omask) != Oquery){
+			syslog(0, logfile, "server: op %d from %I", reqmsg.flags & Omask, buf);
+			continue;
+		}
+
+		if(debug)
+			syslog(0, logfile, "%d: serve (%s) %d %s %s",
+				req.id, caller ? caller->raddr : 0,
+				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){
+				if(dnzone(&reqmsg, &repmsg, &req, rfd, caller) < 0)
+					break;
+			} else {
+				dnserver(&reqmsg, &repmsg, &req);
+				if(reply(rfd, &repmsg, &req, caller) < 0)
+					break;
+				rrfreelist(repmsg.qd);
+				rrfreelist(repmsg.an);
+				rrfreelist(repmsg.ns);
+				rrfreelist(repmsg.ar);
+			}
+		}
+
+		rrfreelist(reqmsg.qd);
+		rrfreelist(reqmsg.an);
+		rrfreelist(reqmsg.ns);
+		rrfreelist(reqmsg.ar);
+	}
+}
+
+enum {
+	Maxactivetcp = 4,
+};
+
+extern char *portname;
+
+static int
+tcpannounce(char *mntpt)
+{
+	int fd;
+	char an[40];
+	
+	USED(mntpt);
+	snprint(an, sizeof an, "tcp!*!%s", portname);
+	if((fd=announce(an, adir)) < 0)
+		warning("announce %s: %r", an);
+	return fd;
+}
+
+void
+dntcpserver(void *v)
+{
+	int i, fd;
+	char *mntpt;
+
+	mntpt = v;
+	while((fd = tcpannounce(mntpt)) < 0)
+		sleep(5*1000);
+
+	for(i=0; i<Maxactivetcp; i++)
+		proccreate(tcpproc, (void*)fd, STACK);
+}