netdev - [PATCH v12 nf-next 2/2] netfilter: nft_chain_filter: Add bridge double vlan and pppoe

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Message-ID: <20250617065835.23428-3-ericwouds@gmail.com>
Date: Tue, 17 Jun 2025 08:58:35 +0200
From: Eric Woudstra <ericwouds@...il.com>
To: Pablo Neira Ayuso <pablo@...filter.org>,
	Jozsef Kadlecsik <kadlec@...filter.org>,
	Nikolay Aleksandrov <razor@...ckwall.org>,
	Ido Schimmel <idosch@...dia.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>
Cc: netfilter-devel@...r.kernel.org,
	bridge@...ts.linux.dev,
	netdev@...r.kernel.org,
	Eric Woudstra <ericwouds@...il.com>
Subject: [PATCH v12 nf-next 2/2] netfilter: nft_chain_filter: Add bridge double vlan and pppoe

This adds the capability to evaluate 802.1ad, QinQ, PPPoE and PPPoE-in-Q
packets in the bridge filter chain.

Signed-off-by: Eric Woudstra <ericwouds@...il.com>
---
 net/netfilter/nft_chain_filter.c | 55 +++++++++++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_chain_filter.c b/net/netfilter/nft_chain_filter.c
index 19a553550c76..b9ab1916be94 100644
--- a/net/netfilter/nft_chain_filter.c
+++ b/net/netfilter/nft_chain_filter.c
@@ -232,11 +232,57 @@ nft_do_chain_bridge(void *priv,
 		    struct sk_buff *skb,
 		    const struct nf_hook_state *state)
 {
+	__be16 outer_proto, proto = 0;
 	struct nft_pktinfo pkt;
+	int ret, offset = 0;
 
 	nft_set_pktinfo(&pkt, skb, state);
 
 	switch (eth_hdr(skb)->h_proto) {
+	case htons(ETH_P_PPP_SES): {
+		struct ppp_hdr {
+			struct pppoe_hdr hdr;
+			__be16 proto;
+		} *ph;
+
+		if (!pskb_may_pull(skb, PPPOE_SES_HLEN))
+			break;
+		offset = PPPOE_SES_HLEN;
+		outer_proto = skb->protocol;
+		ph = (struct ppp_hdr *)(skb->data);
+		__skb_pull(skb, offset);
+		skb_reset_network_header(skb);
+		switch (ph->proto) {
+		case htons(PPP_IP):
+			proto = htons(ETH_P_IP);
+			break;
+		case htons(PPP_IPV6):
+			proto = htons(ETH_P_IPV6);
+			break;
+		}
+		skb->protocol = proto;
+		break;
+	}
+	case htons(ETH_P_8021Q): {
+		struct vlan_hdr *vhdr;
+
+		if (!pskb_may_pull(skb, VLAN_HLEN))
+			break;
+		offset = VLAN_HLEN;
+		outer_proto = skb->protocol;
+		vhdr = (struct vlan_hdr *)(skb->data);
+		__skb_pull(skb, offset);
+		skb_reset_network_header(skb);
+		proto = vhdr->h_vlan_encapsulated_proto;
+		skb->protocol = proto;
+		break;
+	}
+	default:
+		proto = eth_hdr(skb)->h_proto;
+		break;
+	}
+
+	switch (proto) {
 	case htons(ETH_P_IP):
 		nft_set_pktinfo_ipv4_validate(&pkt);
 		break;
@@ -248,7 +294,14 @@ nft_do_chain_bridge(void *priv,
 		break;
 	}
 
-	return nft_do_chain(&pkt, priv);
+	ret = nft_do_chain(&pkt, priv);
+
+	if (offset) {
+		__skb_push(skb, offset);
+		skb_reset_network_header(skb);
+		skb->protocol = outer_proto;
+	}
+	return ret;
 }
 
 static const struct nft_chain_type nft_chain_filter_bridge = {
-- 
2.47.1