From 289d89d80f8229347fc52a6d0c390e9816e13971 Mon Sep 17 00:00:00 2001
From: Brooks Davis <brooks@FreeBSD.org>
Date: Thu, 28 Jul 2005 15:30:19 +0000
Subject: [PATCH] Further fix receive_packet() by using BPF_WORDALIGN to insure
 the offset is properly aligned when we move to the next packet.

Obtained from:	ISC dhclient via krw at OpenBSD
---
 sbin/dhclient/bpf.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/sbin/dhclient/bpf.c b/sbin/dhclient/bpf.c
index abda36e61e64..911acb49407f 100644
--- a/sbin/dhclient/bpf.c
+++ b/sbin/dhclient/bpf.c
@@ -325,7 +325,9 @@ receive_packet(struct interface_info *interface, unsigned char *buf,
 		 * do is drop it.
 		 */
 		if (hdr.bh_caplen != hdr.bh_datalen) {
-			interface->rbuf_offset += hdr.bh_caplen;
+			interface->rbuf_offset =
+			    BPF_WORDALIGN(interface->rbuf_offset +
+			    hdr.bh_caplen);
 			continue;
 		}
 
@@ -339,7 +341,9 @@ receive_packet(struct interface_info *interface, unsigned char *buf,
 		 * this packet.
 		 */
 		if (offset < 0) {
-			interface->rbuf_offset += hdr.bh_caplen;
+			interface->rbuf_offset =
+			    BPF_WORDALIGN(interface->rbuf_offset +
+			    hdr.bh_caplen);
 			continue;
 		}
 		interface->rbuf_offset += offset;
@@ -351,7 +355,9 @@ receive_packet(struct interface_info *interface, unsigned char *buf,
 
 		/* If the IP or UDP checksum was bad, skip the packet... */
 		if (offset < 0) {
-			interface->rbuf_offset += hdr.bh_caplen;
+			interface->rbuf_offset =
+			    BPF_WORDALIGN(interface->rbuf_offset +
+			    hdr.bh_caplen);
 			continue;
 		}
 		interface->rbuf_offset += offset;
@@ -363,14 +369,18 @@ receive_packet(struct interface_info *interface, unsigned char *buf,
 		 * life, though).
 		 */
 		if (hdr.bh_caplen > len) {
-			interface->rbuf_offset += hdr.bh_caplen;
+			interface->rbuf_offset =
+			    BPF_WORDALIGN(interface->rbuf_offset +
+			    hdr.bh_caplen);
 			continue;
 		}
 
 		/* Copy out the data in the packet... */
 		memcpy(buf, interface->rbuf + interface->rbuf_offset,
 		    hdr.bh_caplen);
-		interface->rbuf_offset += hdr.bh_caplen;
+		interface->rbuf_offset =
+		    BPF_WORDALIGN(interface->rbuf_offset +
+		    hdr.bh_caplen);
 		return (hdr.bh_caplen);
 	} while (!length);
 	return (0);