From ccd740cbc6e01b2a08baa341867063ed2887f4b9 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Fri, 29 May 2015 11:28:26 -0700 Subject: [PATCH] vti6: Add pmtu handling to vti6_xmit. We currently rely on the PMTU discovery of xfrm. However if a packet is localy sent, the PMTU mechanism of xfrm tries to to local socket notification what might not work for applications like ping that don't check for this. So add pmtu handling to vti6_xmit to report MTU changes immediately. Signed-off-by: Steffen Klassert Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv6/ip6_vti.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index ff3bd863fa03..0224c032dca5 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -435,6 +435,7 @@ vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl) struct net_device *tdev; struct xfrm_state *x; int err = -1; + int mtu; if (!dst) goto tx_err_link_failure; @@ -468,6 +469,19 @@ vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl) skb_dst_set(skb, dst); skb->dev = skb_dst(skb)->dev; + mtu = dst_mtu(dst); + if (!skb->ignore_df && skb->len > mtu) { + skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu); + + if (skb->protocol == htons(ETH_P_IPV6)) + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); + else + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, + htonl(mtu)); + + return -EMSGSIZE; + } + err = dst_output(skb); if (net_xmit_eval(err) == 0) { struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats); -- 2.20.1