ip_tunnel: fix over-mtu packet send fail without TUNNEL_DONT_FRAGMENT flags

The tunnel device such as vxlan, bareudp and geneve in the lwt mode set
the outer df only based TUNNEL_DONT_FRAGMENT.
And this was also the behavior for gre device before switching to use
ip_md_tunnel_xmit in commit 962924fa2b7a ("ip_gre: Refactor collect
metatdata mode tunnel xmit to ip_md_tunnel_xmit")

When the ip_gre in lwt mode xmit with ip_md_tunnel_xmi changed the rule and
make the discrepancy between handling of DF by different tunnels. So in the
ip_md_tunnel_xmit should follow the same rule like other tunnels.

Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Link: https://lore.kernel.org/r/1604028728-31100-1-git-send-email-wenxu@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 8b04d1dcfec4eb5d0fb697497e0e5599ce8704f1..ee65c9225178d66948a7b70b3d243499eadbc168 100644 (file)
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -608,9 +608,6 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                        ttl = ip4_dst_hoplimit(&rt->dst);
        }
 
-       if (!df && skb->protocol == htons(ETH_P_IP))
-               df = inner_iph->frag_off & htons(IP_DF);
-
        headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
        if (headroom > dev->needed_headroom)
                dev->needed_headroom = headroom;