The ip_gre_calc_hlen() already counts gre's base header len (4-byte)
plus optional header's len, so tunnel->hlen has the entire gre
headeri + options len. Thus, remove the -4 and +4 when calculating
the needed_headroom and mtu.
Fixes: 4565e9919cda ("gre: Setup and TX path for gre/UDP foo-over-udp
encapsulation")
Signed-off-by: William Tu <u9012...@gmail.com>
Cc: Tom Herbert <t...@quantonium.net>
---
net/ipv4/ip_gre.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index c105a315b1a3..286065c35959 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -947,8 +947,8 @@ static void __gre_tunnel_init(struct net_device *dev)
t_hlen = tunnel->hlen + sizeof(struct iphdr);
- dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4;
- dev->mtu = ETH_DATA_LEN - t_hlen - 4;
+ dev->needed_headroom = LL_MAX_HEADER + t_hlen;
+ dev->mtu = ETH_DATA_LEN - t_hlen;
dev->features |= GRE_FEATURES;
dev->hw_features |= GRE_FEATURES;
--
2.7.4
