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author | Tao Liu <thomas.liu@ucloud.cn> | 2022-02-18 17:35:24 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-02 13:42:49 +0300 |
commit | dac2490d9ee0b89dffc72f1172b8bbeb60eaec39 (patch) | |
tree | d4f58c2d98cdbd4acca61039abebf2bff0bdfd6d /net/ipv6 | |
parent | b692d5dc6f541961379e123e31c4bea8ba0725f1 (diff) | |
download | linux-dac2490d9ee0b89dffc72f1172b8bbeb60eaec39.tar.xz |
gso: do not skip outer ip header in case of ipip and net_failover
commit cc20cced0598d9a5ff91ae4ab147b3b5e99ee819 upstream.
We encounter a tcp drop issue in our cloud environment. Packet GROed in
host forwards to a VM virtio_net nic with net_failover enabled. VM acts
as a IPVS LB with ipip encapsulation. The full path like:
host gro -> vm virtio_net rx -> net_failover rx -> ipvs fullnat
-> ipip encap -> net_failover tx -> virtio_net tx
When net_failover transmits a ipip pkt (gso_type = 0x0103, which means
SKB_GSO_TCPV4, SKB_GSO_DODGY and SKB_GSO_IPXIP4), there is no gso
did because it supports TSO and GSO_IPXIP4. But network_header points to
inner ip header.
Call Trace:
tcp4_gso_segment ------> return NULL
inet_gso_segment ------> inner iph, network_header points to
ipip_gso_segment
inet_gso_segment ------> outer iph
skb_mac_gso_segment
Afterwards virtio_net transmits the pkt, only inner ip header is modified.
And the outer one just keeps unchanged. The pkt will be dropped in remote
host.
Call Trace:
inet_gso_segment ------> inner iph, outer iph is skipped
skb_mac_gso_segment
__skb_gso_segment
validate_xmit_skb
validate_xmit_skb_list
sch_direct_xmit
__qdisc_run
__dev_queue_xmit ------> virtio_net
dev_hard_start_xmit
__dev_queue_xmit ------> net_failover
ip_finish_output2
ip_output
iptunnel_xmit
ip_tunnel_xmit
ipip_tunnel_xmit ------> ipip
dev_hard_start_xmit
__dev_queue_xmit
ip_finish_output2
ip_output
ip_forward
ip_rcv
__netif_receive_skb_one_core
netif_receive_skb_internal
napi_gro_receive
receive_buf
virtnet_poll
net_rx_action
The root cause of this issue is specific with the rare combination of
SKB_GSO_DODGY and a tunnel device that adds an SKB_GSO_ tunnel option.
SKB_GSO_DODGY is set from external virtio_net. We need to reset network
header when callbacks.gso_segment() returns NULL.
This patch also includes ipv6_gso_segment(), considering SIT, etc.
Fixes: cb32f511a70b ("ipip: add GSO/TSO support")
Signed-off-by: Tao Liu <thomas.liu@ucloud.cn>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r-- | net/ipv6/ip6_offload.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index a80f90bf3ae7..15c8eef1ef44 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -113,6 +113,8 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, if (likely(ops && ops->callbacks.gso_segment)) { skb_reset_transport_header(skb); segs = ops->callbacks.gso_segment(skb, features); + if (!segs) + skb->network_header = skb_mac_header(skb) + nhoff - skb->head; } if (IS_ERR_OR_NULL(segs)) |