> On 26/09/2020 03:56 Jakub Kicinski <k...@kernel.org> wrote:
>
>
> This reverts commit 546c044c9651e81a16833806feff6b369bb5de33.
>
> Nothing prevents user from sending frames to "external" VxLAN devices.
> In fact kernel itself may generate icmp chatter.
>
> This is fine, such frames should be dropped.
>
> The point of the "missing encapsulation" warning was that
> frames with missing encap should not make it into vxlan_xmit_one().
> And vxlan_xmit() drops them cleanly, so let it just do that.
>
> Without this revert the warning is triggered by the udp_tunnel_nic.sh
> test, but the minimal repro is:
>
> $ ip link add vxlan0 type vxlan \
> group 239.1.1.1 \
> dev lo \
> dstport 1234 \
> external
> $ ip li set dev vxlan0 up
>
> [ 419.165981] vxlan0: Missing encapsulation instructions
> [ 419.166551] WARNING: CPU: 0 PID: 1041 at drivers/net/vxlan.c:2889
> vxlan_xmit+0x15c0/0x1fc0 [vxlan]
>
> Signed-off-by: Jakub Kicinski <k...@kernel.org>
> ---
> drivers/net/vxlan.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
> index fa21d62aa79c..be3bf233a809 100644
> --- a/drivers/net/vxlan.c
> +++ b/drivers/net/vxlan.c
> @@ -2651,6 +2651,11 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct
> net_device *dev,
> udp_sum = !(flags & VXLAN_F_UDP_ZERO_CSUM6_TX);
> label = vxlan->cfg.label;
> } else {
> + if (!info) {
> + WARN_ONCE(1, "%s: Missing encapsulation instructions\n",
> + dev->name);
> + goto drop;
> + }
> remote_ip.sa.sa_family = ip_tunnel_info_af(info);
> if (remote_ip.sa.sa_family == AF_INET) {
> remote_ip.sin.sin_addr.s_addr = info->key.u.ipv4.dst;
> @@ -2885,10 +2890,6 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb,
> struct net_device *dev)
> info->mode & IP_TUNNEL_INFO_TX) {
> vni = tunnel_id_to_key32(info->key.tun_id);
> } else {
> - if (!info)
> - WARN_ONCE(1, "%s: Missing encapsulation
> instructions\n",
> - dev->name);
> -
> if (info && info->mode & IP_TUNNEL_INFO_TX)
> vxlan_xmit_one(skb, dev, vni, NULL, false);
> else
> --
> 2.26.2
Thanks a lot for explanations Jakub. udp_tunnel_nic.sh is a nice tool. Maybe it
could also be used for remcsum testing ? I'd like to check net-next commit
2ae2904b5bac "vxlan: don't collect metadata if remote checksum is wrong" to
make sure it has no impact as I had no ACK. Problem is ip encap-remcsum
requires 'remote' specification not compatible with 'group' and only featuring
in 'new_geneve' function in your script.
If both vxlan_parse_gbp_hdr() and vxlan_remcsum() require metadata recovery, I
can reverse that patch and add some comment in vxlan_rcv()
Best regards,
Fabian
