Fix bug in rarpd:

     Explanation of the bug: when processing its first request, rarpd
     opens a routing socket to send requests to the arp table. It keeps
     that socket open afterwards, while waiting for new RARP requests.

     Meanwhile, the data received on the routing socket fill up until
     they are about 8Kbytes in size. Any additional data is lost.

     When rarpd receives its next RARP request, it tries to access the
     ARP table via a routing socket call, then waits for the answer to
     its own request. This answer is lost because the received data is
     already filled: when looking for the reply, rarpd receives only
     8kbytes worth of data, then loops waiting forever.

     Someone please test it on -STABLE and commit it. We can close the PR
     when testing on STABLE is done.

PR:		bin/5669
Submitted by:	Pierre Beyssac <pb@fasterix.freenix.org>

1 files changed, 13 insertions, 11 deletions

diff --git a/usr.sbin/rarpd/rarpd.c b/usr.sbin/rarpd/rarpd.c
index 619e307..f09c1d6 100644
--- a/usr.sbin/rarpd/rarpd.c
+++ b/usr.sbin/rarpd/rarpd.c
@@ -27,7 +27,7 @@ The Regents of the University of California.  All rights reserved.\n";
 
 #ifndef lint
 static const char rcsid[] =
-	"$Id: rarpd.c,v 1.17 1997/10/13 11:03:36 charnier Exp $";
+	"$Id: rarpd.c,v 1.18 1998/01/16 17:38:54 bde Exp $";
 #endif /* not lint */
 
 /*
@@ -766,18 +766,15 @@ update_arptab(ep, ipaddr)
 	register struct rt_msghdr *rt;
 	register int xtype, xindex;
 	static pid_t pid;
-	static int r, seq;
-	static init = 0;
+	int r;
+	static seq;
 
-	if (!init) {
-		r = socket(PF_ROUTE, SOCK_RAW, 0);
-		if (r < 0) {
-			syslog(LOG_ERR, "raw route socket: %m");
-			exit(1);
-		}
-		pid = getpid();
-		++init;
+	r = socket(PF_ROUTE, SOCK_RAW, 0);
+	if (r < 0) {
+		syslog(LOG_ERR, "raw route socket: %m");
+		exit(1);
 	}
+	pid = getpid();
 
 	ar = &sin_inarp;
 	ar->sin_addr.s_addr = ipaddr;
@@ -797,6 +794,7 @@ update_arptab(ep, ipaddr)
 	errno = 0;
 	if (write(r, rt, rt->rtm_msglen) < 0 && errno != ESRCH) {
 		syslog(LOG_ERR, "rtmsg get write: %m");
+		close(r);
 		return;
 	}
 	do {
@@ -804,6 +802,7 @@ update_arptab(ep, ipaddr)
 	} while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid));
 	if (cc < 0) {
 		syslog(LOG_ERR, "rtmsg get read: %m");
+		close(r);
 		return;
 	}
 	ll2 = (struct sockaddr_dl *)((u_char *)ar2 + ar2->sin_len);
@@ -815,6 +814,7 @@ update_arptab(ep, ipaddr)
 		 */
 		syslog(LOG_ERR, "bogus link family (%d) wrong net for %08X?\n",
 		    ll2->sdl_family, ipaddr);
+		close(r);
 		return;
 	}
 	xtype = ll2->sdl_type;
@@ -841,11 +841,13 @@ update_arptab(ep, ipaddr)
 	errno = 0;
 	if (write(r, rt, rt->rtm_msglen) < 0 && errno != EEXIST) {
 		syslog(LOG_ERR, "rtmsg add write: %m");
+		close(r);
 		return;
 	}
 	do {
 		cc = read(r, rt, sizeof(rtmsg));
 	} while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid));
+	close(r);
 	if (cc < 0) {
 		syslog(LOG_ERR, "rtmsg add read: %m");
 		return;