ipv6 raw fixes

- RFC2292 bis compliance: enable checksumming of ICMPv6 raw
sockets by default, reject odd offsets
- calculate checksum correctly when user forgets to
uninitialize checksum word

* net/ipv6/raw_ipv6.c (rawv6_frag_cksum): Fix offset check. Compensate for any
user-provided checksum.
(rawv6_setsockopt): Reject odd checkum offsets with EINVAL.
(rawv6_init_sk): Enable kernel-computed checksum by default for
IPPROTO_ICMPV6 sockets.

1 files changed, 21 insertions, 2 deletions

diff --git a/pfinet/linux-src/net/ipv6/raw_ipv6.c b/pfinet/linux-src/net/ipv6/raw_ipv6.c
index 9980b3ad..6b93e0f2 100644
--- a/pfinet/linux-src/net/ipv6/raw_ipv6.c
+++ b/pfinet/linux-src/net/ipv6/raw_ipv6.c
@@ -9,6 +9,9 @@
  *
  *	$Id: raw_ipv6.c,v 1.2 2007/10/13 01:43:00 stesie Exp $
  *
+ *	Fixes:
+ *	YOSHIFUJI,H.@USAGI	:	raw checksum (RFC2292(bis) compliance)
+ *
  *	This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
@@ -334,11 +337,18 @@ static int rawv6_frag_cksum(const void *data, struct in6_addr *addr,
 		hdr->cksum = csum_ipv6_magic(addr, daddr, hdr->len,
 					     hdr->proto, hdr->cksum);
 		
-		if (opt->offset < len) {
+		if (opt->offset + 1 < len) {
 			__u16 *csum;
 
 			csum = (__u16 *) (buff + opt->offset);
-			*csum = hdr->cksum;
+			if (*csum) {
+				/* in case cksum was not initialized */
+				__u32 sum = hdr->cksum;
+				sum += *csum;
+				*csum = hdr->cksum = (sum + (sum>>16));
+			} else {
+				*csum = hdr->cksum;
+			}
 		} else {
 			if (net_ratelimit())
 				printk(KERN_DEBUG "icmp: cksum offset too big\n");
@@ -563,6 +573,10 @@ static int rawv6_setsockopt(struct sock *sk, int level, int optname,
 
 	switch (optname) {
 		case IPV6_CHECKSUM:
+			/* You may get strange result with a positive odd offset;
+			   RFC2292bis agrees with me. */
+			if (val > 0 && (val&1))
+				return(-EINVAL);
 			if (val < 0) {
 				opt->checksum = 0;
 			} else {
@@ -638,6 +652,11 @@ static void rawv6_close(struct sock *sk, long timeout)
 
 static int rawv6_init_sk(struct sock *sk)
 {
+	if (sk->num == IPPROTO_ICMPV6){
+		struct raw6_opt *opt = raw6_sk(sk);
+		opt->checksum = 1;
+		opt->offset = 2;
+	}
 	return(0);
 }