On Mon, Sep 30, 2019 at 1:24 AM Sriram Krishnan <srira...@cisco.com> wrote:
>
> When an application sends with AF_PACKET and places a vlan header on
> the raw packet; then the AF_PACKET needs to move the tag into the skb
> so that it gets processed normally through the rest of the transmit
> path.
>
> This is particularly a problem on Hyper-V where the host only allows
> vlan in the offload info.
This sounds like behavior that needs to be addressed in the driver, instead?
> Cc: xe-linux-exter...@cisco.com
> ---
> net/packet/af_packet.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index e2742b0..cfe0904 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1849,15 +1849,35 @@ static int packet_rcv_spkt(struct sk_buff *skb,
> struct net_device *dev,
> return 0;
> }
>
> -static void packet_parse_headers(struct sk_buff *skb, struct socket *sock)
> +static int packet_parse_headers(struct sk_buff *skb, struct socket *sock)
> {
> if ((!skb->protocol || skb->protocol == htons(ETH_P_ALL)) &&
> sock->type == SOCK_RAW) {
If inside this branch, may miss packets with skb->protocol set to one
of the VLAN Ethertypes.
> + __be16 ethertype;
> +
> skb_reset_mac_header(skb);
> +
> + ethertype = eth_hdr(skb)->h_proto;
> + /*
> + * If Vlan tag is present in the packet
> + * move it to skb
> + */
> + if (eth_type_vlan(ethertype)) {
> + int err;
> + __be16 vlan_tci;
> +
> + err = __skb_vlan_pop(skb, &vlan_tci);
> + if (unlikely(err))
> + return err;
> +
> + __vlan_hwaccel_put_tag(skb, ethertype, vlan_tci);
What happens with multiple tags (QinQ)?
> + }
> +
> skb->protocol = dev_parse_header_protocol(skb);
> }
>
> skb_probe_transport_header(skb);
> + return 0;
> }
>
> /*
> @@ -1979,7 +1999,9 @@ static int packet_sendmsg_spkt(struct socket *sock,
> struct msghdr *msg,
> if (unlikely(extra_len == 4))
> skb->no_fcs = 1;
>
> - packet_parse_headers(skb, sock);
> + err = packet_parse_headers(skb, sock);
> + if (err)
> + goto out_unlock;
This only tests the new return value in one of three callers of
packet_sendmsg_spkt.
