[PATCH nf-next v2 1/2] netfilter: nft_meta: add NFT_META_BRI_PVID support

[wenxu@ucloud.cn]

From: wenxu <wenxu@ucloud.cn>

nft add table bridge firewall
nft add chain bridge firewall zones { type filter hook prerouting priority - 300 \; }
nft add rule bridge firewall zones counter ct zone set vlan id map { 100 : 1, 200 : 2 }

As above set the bridge port with pvid, the received packet don't contain
the vlan tag which means the packet should belong to vlan 200 through pvid.
With this pacth user can get the pvid of bridge ports.

So add the following rule for as the first rule in the chain of zones.

nft add rule bridge firewall zones counter meta brvlan set meta brpvid

Signed-off-by: wenxu <wenxu@ucloud.cn>
---
 include/uapi/linux/netfilter/nf_tables.h |  2 ++
 net/netfilter/nft_meta.c                 | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 31a6b8f..4a16124 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -793,6 +793,7 @@ enum nft_exthdr_attributes {
  * @NFT_META_SECPATH: boolean, secpath_exists (!!skb->sp)
  * @NFT_META_IIFKIND: packet input interface kind name (dev->rtnl_link_ops->kind)
  * @NFT_META_OIFKIND: packet output interface kind name (dev->rtnl_link_ops->kind)
+ * @NFT_META_BRI_PVID: packet input bridge port pvid
  */
 enum nft_meta_keys {
 	NFT_META_LEN,
@@ -823,6 +824,7 @@ enum nft_meta_keys {
 	NFT_META_SECPATH,
 	NFT_META_IIFKIND,
 	NFT_META_OIFKIND,
+	NFT_META_BRI_PVID,
 };
 
 /**
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 987d2d6..cb877e01 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -243,6 +243,14 @@ void nft_meta_get_eval(const struct nft_expr *expr,
 			goto err;
 		strncpy((char *)dest, p->br->dev->name, IFNAMSIZ);
 		return;
+	case NFT_META_BRI_PVID:
+		if (in == NULL || (p = br_port_get_rtnl_rcu(in)) == NULL)
+			goto err;
+		if (br_opt_get(p->br, BROPT_VLAN_ENABLED)) {
+			nft_reg_store16(dest, br_get_pvid(nbp_vlan_group_rcu(p)));
+			return;
+		}
+		goto err;
 #endif
 	case NFT_META_IIFKIND:
 		if (in == NULL || in->rtnl_link_ops == NULL)
@@ -370,6 +378,11 @@ static int nft_meta_get_init(const struct nft_ctx *ctx,
 			return -EOPNOTSUPP;
 		len = IFNAMSIZ;
 		break;
+	case NFT_META_BRI_PVID:
+		if (ctx->family != NFPROTO_BRIDGE)
+			return -EOPNOTSUPP;
+		len = sizeof(u16);
+		break;
 #endif
 	default:
 		return -EOPNOTSUPP;
-- 
1.8.3.1