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....@gmail.com>
---
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 2a4ef9d..fad0bb1 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;
--
2.1.0
