fix alignment constraint in IPv6 routing header manipulation (ancillary data).

documented in RFC2292.
from: shin@kame.net

1 files changed, 19 insertions, 7 deletions

diff --git a/src/lib/libc/net/rthdr.c b/src/lib/libc/net/rthdr.c
index 2dff59668e..5cd485889b 100644
--- a/src/lib/libc/net/rthdr.c
+++ b/src/lib/libc/net/rthdr.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: rthdr.c,v 1.1 1999/12/11 08:09:11 itojun Exp $        */
+/*      $OpenBSD: rthdr.c,v 1.2 2000/02/29 18:25:52 itojun Exp $        */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -63,7 +63,9 @@ inet6_rthdr_init(bp, type)
     int type;
 {
     register struct cmsghdr *ch = (struct cmsghdr *)bp;
-    register struct ip6_rthdr *rthdr = (struct ip6_rthdr *)(ch + 1);
+    register struct ip6_rthdr *rthdr;
+
+    rthdr = (struct ip6_rthdr *)CMSG_DATA(ch);
 
     ch->cmsg_level = IPPROTO_IPV6;
     ch->cmsg_type = IPV6_RTHDR;
@@ -88,7 +90,9 @@ inet6_rthdr_add(cmsg, addr, flags)
     const struct in6_addr *addr;
     u_int flags;
 {
-    register struct ip6_rthdr *rthdr = (struct ip6_rthdr *)(cmsg + 1);
+    register struct ip6_rthdr *rthdr;
+
+    rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
 
     switch(rthdr->ip6r_type) {
      case IPV6_RTHDR_TYPE_0:
@@ -135,7 +139,9 @@ inet6_rthdr_lasthop(cmsg, flags)
     struct cmsghdr *cmsg;
     unsigned int flags;
 {
-    register struct ip6_rthdr *rthdr = (struct ip6_rthdr *)(cmsg + 1);
+    register struct ip6_rthdr *rthdr;
+
+    rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
 
     switch(rthdr->ip6r_type) {
      case IPV6_RTHDR_TYPE_0:
@@ -189,7 +195,9 @@ int
 inet6_rthdr_segments(cmsg)
     const struct cmsghdr *cmsg;
 {
-    register struct ip6_rthdr *rthdr = (struct ip6_rthdr *)(cmsg + 1);
+    register struct ip6_rthdr *rthdr;
+
+    rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
 
     switch(rthdr->ip6r_type) {
     case IPV6_RTHDR_TYPE_0:
@@ -221,7 +229,9 @@ inet6_rthdr_getaddr(cmsg, index)
     struct cmsghdr *cmsg;
     int index;
 {
-    register struct ip6_rthdr *rthdr = (struct ip6_rthdr *)(cmsg + 1);
+    register struct ip6_rthdr *rthdr;
+
+    rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
 
     switch(rthdr->ip6r_type) {
     case IPV6_RTHDR_TYPE_0:
@@ -260,7 +270,9 @@ inet6_rthdr_getflags(cmsg, index)
     const struct cmsghdr *cmsg;
     int index;
 {
-    register struct ip6_rthdr *rthdr = (struct ip6_rthdr *)(cmsg + 1);
+    register struct ip6_rthdr *rthdr;
+
+    rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
 
     switch(rthdr->ip6r_type) {
     case IPV6_RTHDR_TYPE_0: