From c88f8d5cd95fd039cff95d682b8e71100c001df0 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Wed, 26 Apr 2023 23:00:06 -0700 Subject: sit: update dev->needed_headroom in ipip6_tunnel_bind_dev() 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 Link: https://lore.kernel.org/netdev/CAGyP=7fDcSPKu6nttbGwt7RXzE3uyYxLjCSE97J64pRxJP8jPA@mail.gmail.com/ Cc: Kuniyuki Iwashima Cc: Eric Dumazet Signed-off-by: Cong Wang Reviewed-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Signed-off-by: David S. Miller --- 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 063560e2cb1a..cc24cefdb85c 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -1095,12 +1095,13 @@ tx_err: 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) { @@ -1123,14 +1124,15 @@ 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, -- cgit