From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Sriram Krishnan <srirakr2@cisco.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
xe-linux-external@cisco.com,
"David S. Miller" <davem@davemloft.net>,
Network Development <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] AF_PACKET doesnt strip VLAN information
Date: Mon, 30 Sep 2019 11:16:14 -0400 [thread overview]
Message-ID: <CA+FuTSfN5=xkYUKiafM3uKF37kV6mg0Cn5WGv2QF887Pyw5A5g@mail.gmail.com> (raw)
In-Reply-To: <1569646705-10585-1-git-send-email-srirakr2@cisco.com>
On Mon, Sep 30, 2019 at 1:24 AM Sriram Krishnan <srirakr2@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-external@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.
next prev parent reply other threads:[~2019-09-30 15:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-28 4:58 [PATCH] AF_PACKET doesnt strip VLAN information Sriram Krishnan
2019-09-30 15:16 ` Willem de Bruijn [this message]
2019-10-01 15:44 ` Stephen Hemminger
2019-10-01 15:52 ` Willem de Bruijn
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