Commit 18bed891 authored by Yoshiki Komachi's avatar Yoshiki Komachi Committed by David S. Miller

af_packet: fix the tx skb protocol in raw sockets with ETH_P_ALL

I am using "protocol ip" filters in TC to manipulate TC flower
classifiers, which are only available with "protocol ip". However,
I faced an issue that packets sent via raw sockets with ETH_P_ALL
did not match the ip filters even if they did satisfy the condition
(e.g., DHCP offer from dhcpd).

I have determined that the behavior was caused by an unexpected
value stored in skb->protocol, namely, ETH_P_ALL instead of ETH_P_IP,
when packets were sent via raw sockets with ETH_P_ALL set.

IMHO, storing ETH_P_ALL in skb->protocol is not appropriate for
packets sent via raw sockets because ETH_P_ALL is not a real ether
type used on wire, but a virtual one.

This patch fixes the tx protocol selection in cases of transmission
via raw sockets created with ETH_P_ALL so that it asks the driver to
extract protocol from the Ethernet header.

Fixes: 75c65772 ("net/packet: Ask driver for protocol if not provided by user")
Signed-off-by: default avatarYoshiki Komachi <komachi.yoshiki@lab.ntt.co.jp>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a4dc6a49
...@@ -1852,7 +1852,8 @@ static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev, ...@@ -1852,7 +1852,8 @@ static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,
static void packet_parse_headers(struct sk_buff *skb, struct socket *sock) static void packet_parse_headers(struct sk_buff *skb, struct socket *sock)
{ {
if (!skb->protocol && sock->type == SOCK_RAW) { if ((!skb->protocol || skb->protocol == htons(ETH_P_ALL)) &&
sock->type == SOCK_RAW) {
skb_reset_mac_header(skb); skb_reset_mac_header(skb);
skb->protocol = dev_parse_header_protocol(skb); skb->protocol = dev_parse_header_protocol(skb);
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment