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authorXin Long <lucien.xin@gmail.com>2017-10-01 22:00:55 +0800
committerDavid S. Miller <davem@davemloft.net>2017-10-01 22:30:32 -0700
commitc122fda271717f4fc618e0a31e833941fd5f1efd (patch)
tree3cb94ac33a0d66a34ddeaf8ba7aba32a43788518 /net/ipv4/ip_gre.c
parent5513d08d29511c263c00933c00dd7a82fffda3c9 (diff)
downloadlinux-c122fda271717f4fc618e0a31e833941fd5f1efd.tar.gz
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 <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_gre.c')
-rw-r--r--net/ipv4/ip_gre.c4
1 files changed, 3 insertions, 1 deletions
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;