ip_gre: clear feature flags when incompatible o_flags are set

[ Upstream commit 1cc5954f44150bb70cac07c3cc5df7cf0dfb61ec ]

Commit dd9d598c6657 ("ip_gre: add the support for i/o_flags update via
netlink") added the ability to change o_flags, but missed that the
GSO/LLTX features are disabled by default, and only enabled some gre
features are unused. Thus we also need to disable the GSO/LLTX features
on the device when the TUNNEL_SEQ or TUNNEL_CSUM flags are set.

These two examples should result in the same features being set:

    ip link add gre_none type gre local 192.168.0.10 remote 192.168.0.20 ttl 255 key 0

    ip link set gre_none type gre seq
    ip link add gre_seq type gre local 192.168.0.10 remote 192.168.0.20 ttl 255 key 1 seq

Fixes: dd9d598c6657 ("ip_gre: add the support for i/o_flags update via netlink")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 01bbbfe2c2a7a1500e0ebbc41de5e3dc2fbcc140..3686434d134bb9a31a16bc65ddc93f7afbcb584e 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -796,8 +796,14 @@ static void ipgre_link_update(struct net_device *dev, bool set_mtu)
                    tunnel->encap.type == TUNNEL_ENCAP_NONE) {
                        dev->features |= NETIF_F_GSO_SOFTWARE;
                        dev->hw_features |= NETIF_F_GSO_SOFTWARE;
+               } else {
+                       dev->features &= ~NETIF_F_GSO_SOFTWARE;
+                       dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
                }
                dev->features |= NETIF_F_LLTX;
+       } else {
+               dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
+               dev->features &= ~(NETIF_F_LLTX | NETIF_F_GSO_SOFTWARE);
        }
 }