From c122fda271717f4fc618e0a31e833941fd5f1efd Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sun, 1 Oct 2017 22:00:55 +0800 Subject: [PATCH] ip_gre: set tunnel hlen properly in erspan_tunnel_init According to __gre_tunnel_init, tunnel->hlen should be set as the headers' length between inner packet and outer iphdr. It would be used especially to calculate a proper mtu when updating mtu in tnl_update_pmtu. Now without setting it, a bigger mtu value than expected would be updated, which hurts performance a lot. This patch is to fix it by setting tunnel->hlen with: tunnel->tun_hlen + tunnel->encap_hlen + sizeof(struct erspanhdr) Fixes: 84e54fe0a5ea ("gre: introduce native tunnel support for ERSPAN") Signed-off-by: Xin Long Signed-off-by: David S. Miller --- net/ipv4/ip_gre.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 2a4ef9dc48ff..fad0bb1e3e9a 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -1245,7 +1245,9 @@ static int erspan_tunnel_init(struct net_device *dev) tunnel->tun_hlen = 8; tunnel->parms.iph.protocol = IPPROTO_GRE; - t_hlen = tunnel->hlen + sizeof(struct iphdr) + sizeof(struct erspanhdr); + tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen + + sizeof(struct erspanhdr); + t_hlen = tunnel->hlen + sizeof(struct iphdr); dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4; dev->mtu = ETH_DATA_LEN - t_hlen - 4;