[PATCH 2/2] ipvs: Extend MTU check to account for IPv6 NAT defrag changes

Jesper Dangaard Brouer
2012-08-27T14:42:27Z

This patch is necessary, to make IPVS work, after Patrick McHardys
IPv6 NAT defragmentation changes.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---

I would appriciate, if someone (e.g. Julian) double check the tunnel mode code.
--Jesper

net/netfilter/ipvs/ip_vs_xmit.c | 16 +++++++++++++---
1 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index e56f0df..20763de 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -88,7 +88,14 @@ __ip_vs_dst_check(struct ip_vs_dest *dest, u32 rtos)
static inline bool
__mtu_check_toobig_v6(const struct sk_buff *skb, u32 mtu)
{
- if (skb->len > mtu && !skb_is_gso(skb)) {
+ if (IP6CB(skb)->frag_max_size) {
+ /* frag_max_size tell us that, this packet have been
+ * defragmented by netfilter IPv6 conntrack module.
+ */
+ if (IP6CB(skb)->frag_max_size > mtu)
+ return true; /* largest fragment violate MTU */
+ }
+ else if (skb->len > mtu && !skb_is_gso(skb)) {
return true; /* Packet size violate MTU size */
}
return false;
@@ -956,8 +963,11 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);

/* MTU checking: Special for tunnel mode */
- if (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr) &&
- !skb_is_gso(skb)) {
+ if ((!IP6CB(skb)->frag_max_size &&
+ (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr) &&
+ !skb_is_gso(skb)))
+ || IP6CB(skb)->frag_max_size + sizeof(struct ipv6hdr) > mtu) {
+
if (!skb->dev) {
struct net *net = dev_net(skb_dst(skb)->dev);