ip_tunnel: fix ipv4 pmtu check to honor inner ip header df (fc24f2b2) · Commits · 戴 / test

Frag needed should be sent only if the inner header asked to not fragment. Currently fragmentation is broken if the tunnel has df set, but df was not asked in the original packet. The tunnel's df needs to be still checked to update internally the pmtu cache. Commit broke it, and this commit fixes the ipv4 df check back to the way it was. Fixes: ("ip_tunnels: Use skb-len to PMTU check.") Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by:

Timo Teräs <timo.teras@iki.fi> Acked-by:

Pravin B Shelar <pshelar@nicira.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv4/ip_tunnel.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -586,7 +586,8 @@ int ip_tunnel_encap(struct sk_buff skb, struct ip_tunnel t,
		EXPORT_SYMBOL(ip_tunnel_encap);

		static int tnl_update_pmtu(struct net_device dev, struct sk_buff skb,
		struct rtable *rt, __be16 df)
		struct rtable *rt, __be16 df,
		const struct iphdr *inner_iph)
		{
		struct ip_tunnel *tunnel = netdev_priv(dev);
		int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len;
		@@ -603,7 +604,8 @@ static int tnl_update_pmtu(struct net_device dev, struct sk_buff skb,

		if (skb->protocol == htons(ETH_P_IP)) {
		if (!skb_is_gso(skb) &&
		(df & htons(IP_DF)) && mtu < pkt_size) {
		(inner_iph->frag_off & htons(IP_DF)) &&
		mtu < pkt_size) {
		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
		return -E2BIG;
		@@ -737,7 +739,7 @@ void ip_tunnel_xmit(struct sk_buff skb, struct net_device dev,
		goto tx_error;
		}

		if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off)) {
		if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off, inner_iph)) {
		ip_rt_put(rt);
		goto tx_error;
		}

Admin message