From: claudio <claudio@openbsd.org>
Date: Tue, 20 Jul 2010 05:26:06 +0000 (+0000)
Subject: Another hand rolled offsetof(), replace with mask2prefixlen from kroute.c
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=1c6cf06e2905abe3bb1d5c7942f9138bcc358e6f;p=openbsd

Another hand rolled offsetof(), replace with mask2prefixlen from kroute.c
which was copied from bgpd. Found by deraadt@
---

diff --git a/usr.sbin/ospf6ctl/parser.c b/usr.sbin/ospf6ctl/parser.c
index ef1d0e3cc6f..7d076ea7c2e 100644
--- a/usr.sbin/ospf6ctl/parser.c
+++ b/usr.sbin/ospf6ctl/parser.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parser.c,v 1.8 2010/01/13 11:33:12 jsg Exp $ */
+/*	$OpenBSD: parser.c,v 1.9 2010/07/20 05:26:06 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
@@ -343,17 +343,17 @@ parse_prefix(const char *word, struct in6_addr *addr, u_int8_t *prefixlen)
 u_int8_t
 mask2prefixlen(struct sockaddr_in6 *sa_in6)
 {
-	u_int8_t	l = 0, i, len;
+	u_int8_t	l = 0, *ap, *ep;
 
 	/*
 	 * sin6_len is the size of the sockaddr so substract the offset of
 	 * the possibly truncated sin6_addr struct.
 	 */
-	len = sa_in6->sin6_len -
-	    (u_int8_t)(&((struct sockaddr_in6 *)NULL)->sin6_addr);
-	for (i = 0; i < len; i++) {
+	ap = (u_int8_t *)&sa_in6->sin6_addr;
+	ep = (u_int8_t *)sa_in6 + sa_in6->sin6_len;
+	for (; ap < ep; ap++) {
 		/* this "beauty" is adopted from sbin/route/show.c ... */
-		switch (sa_in6->sin6_addr.s6_addr[i]) {
+		switch (*ap) {
 		case 0xff:
 			l += 8;
 			break;