From dd767856a36e00b631d65ebc4bb81b19915532d6 Mon Sep 17 00:00:00 2001
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Tue, 11 Oct 2011 01:44:30 +0000
Subject: [PATCH] xfrm6: Don't call icmpv6_send on local error
Calling icmpv6_send() on a local message size error leads to
an incorrect update of the path mtu. So use xfrm6_local_rxpmtu()
to notify about the pmtu if the IPV6_DONTFRAG socket option is
set on an udp or raw socket, according RFC 3542 and use
ipv6_local_error() otherwise.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/xfrm6_output.c | 56 +++++++++++++++++++++++++++++++++++++++--
1 file changed, 54 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 49a91c5f5623..faae41737fca 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -28,6 +28,43 @@ int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
EXPORT_SYMBOL(xfrm6_find_1stfragopt);
+static int xfrm6_local_dontfrag(struct sk_buff *skb)
+{
+ int proto;
+ struct sock *sk = skb->sk;
+
+ if (sk) {
+ proto = sk->sk_protocol;
+
+ if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
+ return inet6_sk(sk)->dontfrag;
+ }
+
+ return 0;
+}
+
+static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
+{
+ struct flowi6 fl6;
+ struct sock *sk = skb->sk;
+
+ fl6.flowi6_oif = sk->sk_bound_dev_if;
+ ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->daddr);
+
+ ipv6_local_rxpmtu(sk, &fl6, mtu);
+}
+
+static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
+{
+ struct flowi6 fl6;
+ struct sock *sk = skb->sk;
+
+ fl6.fl6_dport = inet_sk(sk)->inet_dport;
+ ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->daddr);
+
+ ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
+}
+
static int xfrm6_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
@@ -39,7 +76,13 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb)
if (!skb->local_df && skb->len > mtu) {
skb->dev = dst->dev;
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+
+ if (xfrm6_local_dontfrag(skb))
+ xfrm6_local_rxpmtu(skb, mtu);
+ else if (skb->sk)
+ xfrm6_local_error(skb, mtu);
+ else
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
ret = -EMSGSIZE;
}
@@ -93,9 +136,18 @@ static int __xfrm6_output(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
+ int mtu = ip6_skb_dst_mtu(skb);
+
+ if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
+ xfrm6_local_rxpmtu(skb, mtu);
+ return -EMSGSIZE;
+ } else if (!skb->local_df && skb->len > mtu && skb->sk) {
+ xfrm6_local_error(skb, mtu);
+ return -EMSGSIZE;
+ }
if ((x && x->props.mode == XFRM_MODE_TUNNEL) &&
- ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
+ ((skb->len > mtu && !skb_is_gso(skb)) ||
dst_allfrag(skb_dst(skb)))) {
return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);
}
--
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