net: handle ARPHRD_PPP in dev_is_mac_header_xmit()

commit a4f39c9f14a634e4cd35fcd338c239d11fcc73fc upstream.

The goal is to support a bpf_redirect() from an ethernet device (ingress)
to a ppp device (egress).
The l2 header is added automatically by the ppp driver, thus the ethernet
header should be removed.

CC: stable@vger.kernel.org
Fixes: 27b29f63058d ("bpf: add bpf_redirect() helper")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Siwar Zitouni <siwar.zitouni@6wind.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/if_arp.h b/include/linux/if_arp.h
index a9b09c7c2ce02e6387089ac00eb501a5f3db1ea7..c5a2e04465703dbb5bdcf151b6598adc1ebbac15 100644 (file)
--- a/include/linux/if_arp.h
+++ b/include/linux/if_arp.h
@@ -56,6 +56,10 @@ static inline bool dev_is_mac_header_xmit(const struct net_device *dev)
        case ARPHRD_NONE:
        case ARPHRD_RAWIP:
        case ARPHRD_PIMREG:
+       /* PPP adds its l2 header automatically in ppp_start_xmit().
+        * This makes it look like an l3 device to __bpf_redirect() and tcf_mirred_init().
+        */
+       case ARPHRD_PPP:
                return false;
        default:
                return true;