This change makes it so that we use icmpv6_send to report PMTU issues back
into tunnels in the case that the resulting packet is larger than the MTU
of the outgoing interface. Previously xfrm_local_error was being used in
this case, however this was resulting in no changes, I suspect due to the
fact that the tunnel itself was being kept out of the loop.
This patch fixes PMTU problems seen on ip6_vti tunnels and is based on the
behavior seen if the socket was orphaned. Instead of requiring the socket
to be orphaned this patch simply defaults to using icmpv6_send in the case
that the frame came though a tunnel.
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxx>
---
net/ipv6/xfrm6_output.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 09c76a7b474d..6f9b514d0e38 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -72,6 +72,7 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
struct dst_entry *dst = skb_dst(skb);
+ struct xfrm_state *x = dst->xfrm;
mtu = dst_mtu(dst);
if (mtu < IPV6_MIN_MTU)
@@ -82,7 +83,7 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb)
if (xfrm6_local_dontfrag(skb))
xfrm6_local_rxpmtu(skb, mtu);
- else if (skb->sk)
+ else if (skb->sk && x->props.mode != XFRM_MODE_TUNNEL)
xfrm_local_error(skb, mtu);
else
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
@@ -149,11 +150,16 @@ static int __xfrm6_output(struct sock *sk, struct sk_buff *skb)
else
mtu = dst_mtu(skb_dst(skb));
- if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
- xfrm6_local_rxpmtu(skb, mtu);
- return -EMSGSIZE;
- } else if (!skb->ignore_df && skb->len > mtu && skb->sk) {
- xfrm_local_error(skb, mtu);
+ if (!skb->ignore_df && skb->len > mtu) {
+ skb->dev = dst->dev;
+
+ if (xfrm6_local_dontfrag(skb))
+ xfrm6_local_rxpmtu(skb, mtu);
+ else if (skb->sk && x->props.mode != XFRM_MODE_TUNNEL)
+ xfrm_local_error(skb, mtu);
+ else
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+
return -EMSGSIZE;
}
--
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