From 9b4fb9384042f3c1f48f9ad59c6759f19467eb14 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sat, 27 Jun 1998 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1998-06-27

---
 ip/ipmux.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ip/ipmux.c b/ip/ipmux.c
index e6192415f99dc8d5c21716dfd4f02ef4df93aada..88aee37369a7072a72559fc0628e0b1bfa4f2bff 100644
--- a/ip/ipmux.c
+++ b/ip/ipmux.c
@@ -727,7 +727,9 @@ yes:
 		/* tack on interface address */
 		bp = padblock(bp, IPaddrlen);
 		ipmove(bp->rp, ia);
-		qpass(c->rq, bp);
+		bp = concatblock(bp);
+		if(bp != nil)
+			qpass(c->rq, bp);
 		return;
 	}