From: Guillaume Nault Date: Fri, 25 Jun 2021 13:33:04 +0000 (+0200) Subject: ipip: allow redirecting ipip and mplsip packets to eth devices X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7ad136fd288c0e0177eb29e04ec289e1b873b270;p=linux.git ipip: allow redirecting ipip and mplsip packets to eth devices Even though ipip transports IPv4 or MPLS packets, it needs to reset the mac_header pointer, so that other parts of the stack don't mistakenly access the outer header after the packet has been decapsulated. This allows to push an Ethernet header to ipip or mplsip packets and redirect them to an Ethernet device: $ tc filter add dev ipip0 ingress matchall \ action vlan push_eth dst_mac 00:00:5e:00:53:01 \ src_mac 00:00:5e:00:53:00 \ action mirred egress redirect dev eth0 Without this patch, push_eth refuses to add an ethernet header because the skb appears to already have a MAC header. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller --- diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c index d5bfa087c23ad..266c65577ba68 100644 --- a/net/ipv4/ipip.c +++ b/net/ipv4/ipip.c @@ -242,6 +242,8 @@ static int ipip_tunnel_rcv(struct sk_buff *skb, u8 ipproto) if (!tun_dst) return 0; } + skb_reset_mac_header(skb); + return ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error); }