From: Cong Wang cong.wang@bytedance.com
[ Upstream commit c88f8d5cd95fd039cff95d682b8e71100c001df0 ]
When a tunnel device is bound with the underlying device, its dev->needed_headroom needs to be updated properly. IPv4 tunnels already do the same in ip_tunnel_bind_dev(). Otherwise we may not have enough header room for skb, especially after commit b17f709a2401 ("gue: TX support for using remote checksum offload option").
Fixes: 32b8a8e59c9c ("sit: add IPv4 over IPv4 support") Reported-by: Palash Oswal oswalpalash@gmail.com Link: https://lore.kernel.org/netdev/CAGyP=7fDcSPKu6nttbGwt7RXzE3uyYxLjCSE97J64pRx... Cc: Kuniyuki Iwashima kuniyu@amazon.com Cc: Eric Dumazet edumazet@google.com Signed-off-by: Cong Wang cong.wang@bytedance.com Reviewed-by: Eric Dumazet edumazet@google.com Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv6/sit.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index e5baf5e4782b0..f24a6cd0d15a3 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -1039,12 +1039,13 @@ static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
static void ipip6_tunnel_bind_dev(struct net_device *dev) { + struct ip_tunnel *tunnel = netdev_priv(dev); + int t_hlen = tunnel->hlen + sizeof(struct iphdr); struct net_device *tdev = NULL; - struct ip_tunnel *tunnel; + int hlen = LL_MAX_HEADER; const struct iphdr *iph; struct flowi4 fl4;
- tunnel = netdev_priv(dev); iph = &tunnel->parms.iph;
if (iph->daddr) { @@ -1067,14 +1068,15 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev) tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
if (tdev && !netif_is_l3_master(tdev)) { - int t_hlen = tunnel->hlen + sizeof(struct iphdr); int mtu;
mtu = tdev->mtu - t_hlen; if (mtu < IPV6_MIN_MTU) mtu = IPV6_MIN_MTU; WRITE_ONCE(dev->mtu, mtu); + hlen = tdev->hard_header_len + tdev->needed_headroom; } + dev->needed_headroom = t_hlen + hlen; }
static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,