Re: [PATCH] net: ip_finish_output_gso: If skb_gso_network_seglen exceeds MTU, do segmentation even for non IPSKB_FORWARDED skbs

[Florian Westphal]

Shmulik Ladkani <shmulik.ladk...@ravellosystems.com> wrote:
> I'd appreciate any suggestion how to determine traffic is local OTHER
> THAN testing IPSKB_FORWARDED; If we have such a way, there wouldn't be an
> impact on local traffic.
> 
> > What about setting IPCB FORWARD flag in iptunnel_xmit if
> > skb->skb_iif != 0... instead?
> 
> Can you please elaborate?

[ not even compile tested ]

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -65,6 +65,7 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct 
sk_buff *skb,
        struct net_device *dev = skb->dev;
        struct iphdr *iph;
        int err;
+       bool fwd = skb->skb_iif > 0;
 
        skb_scrub_packet(skb, xnet);
 
@@ -72,6 +73,9 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct 
sk_buff *skb,
        skb_dst_set(skb, &rt->dst);
        memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 
+       if (fwd)
+               IPCB(skb)->flags = IPSKB_FORWARDED;
+
        /* Push down and install the IP header. */
        skb_push(skb, sizeof(struct iphdr));
        skb_reset_network_header(skb);