From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Wed, 23 Aug 2023 13:41:02 +0000 (+0200)
Subject: net: handle ARPHRD_PPP in dev_is_mac_header_xmit()
X-Git-Tag: v6.6.17~4098^2^2~14
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a4f39c9f14a634e4cd35fcd338c239d11fcc73fc;p=platform%2Fkernel%2Flinux-rpi.git

net: handle ARPHRD_PPP in dev_is_mac_header_xmit()

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>
---

diff --git a/include/linux/if_arp.h b/include/linux/if_arp.h
index 1ed5244..10a1e81 100644
--- a/include/linux/if_arp.h
+++ b/include/linux/if_arp.h
@@ -53,6 +53,10 @@ 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;