[ 3.8.y.z extended stable ] Patch "ipv6: Store Router Alert option in IP6CB directly." has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ipv6: Store Router Alert option in IP6CB directly.

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From b214e6b6c817bfd299578aaffc6395de7447404b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?YOSHIFUJI=20Hideaki=20/=20=E5=90=89=E8=97=A4=E8=8B=B1=E6?=
 =?UTF-8?q?=98=8E?= <yoshfuji at linux-ipv6.org>
Date: Sun, 13 Jan 2013 05:02:45 +0000
Subject: ipv6: Store Router Alert option in IP6CB directly.

commit dd3332bfcb2223458f553f341d3388cb84040e6a upstream.

Router Alert option is very small and we can store the value
itself in the skb.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji at linux-ipv6.org>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ kamal: 3.8.y-stable prereq for f46078cfcd77fa5165bf849f5e568a7ac5fa569c
  "ipv6: drop packets with multiple fragmentation headers" ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 include/linux/ipv6.h      | 3 ++-
 include/uapi/linux/ipv6.h | 2 ++
 net/ipv6/exthdrs.c        | 3 ++-
 net/ipv6/ip6_input.c      | 5 ++---
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index faed1e3..8d766c2 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -89,7 +89,7 @@ static inline __u8 ipv6_tclass(const struct ipv6hdr *iph)

 struct inet6_skb_parm {
 	int			iif;
-	__u16			ra;
+	__be16			ra;
 	__u16			hop;
 	__u16			dst0;
 	__u16			srcrt;
@@ -105,6 +105,7 @@ struct inet6_skb_parm {
 #define IP6SKB_XFRM_TRANSFORMED	1
 #define IP6SKB_FORWARDED	2
 #define IP6SKB_REROUTED		4
+#define IP6SKB_ROUTERALERT	8
 };

 #define IP6CB(skb)	((struct inet6_skb_parm*)((skb)->cb))
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 5a2991c..4bda4cf 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -63,6 +63,8 @@ struct ipv6_opt_hdr {
 #define ipv6_destopt_hdr ipv6_opt_hdr
 #define ipv6_hopopt_hdr  ipv6_opt_hdr

+/* Router Alert option values (RFC2711) */
+#define IPV6_OPT_ROUTERALERT_MLD	0x0000	/* MLD(RFC2710) */

 /*
  *	routing header type 0 (used in cmsghdr struct)
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 473f628..07a7d65 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -553,7 +553,8 @@ static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 	const unsigned char *nh = skb_network_header(skb);

 	if (nh[optoff + 1] == 2) {
-		IP6CB(skb)->ra = optoff;
+		IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
+		memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 		return true;
 	}
 	LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index dee9964..5345300 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -302,9 +302,8 @@ int ip6_mc_input(struct sk_buff *skb)
 		struct inet6_skb_parm *opt = IP6CB(skb);

 		/* Check for MLD */
-		if (unlikely(opt->ra)) {
+		if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
 			/* Check if this is a mld message */
-			u8 *ptr = skb_network_header(skb) + opt->ra;
 			struct icmp6hdr *icmp6;
 			u8 nexthdr = hdr->nexthdr;
 			__be16 frag_off;
@@ -313,7 +312,7 @@ int ip6_mc_input(struct sk_buff *skb)
 			/* Check if the value of Router Alert
 			 * is for MLD (0x0000).
 			 */
-			if ((ptr[2] | ptr[3]) == 0) {
+			if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
 				deliver = false;

 				if (!ipv6_ext_hdr(nexthdr)) {
--
1.8.1.2