[PATCH v3] netfilter: nf_tables: add pkttype support to meta expression

[Ana Rey <anarey@gmail.com>]

From: Álvaro Neira Ayuso <alvaroneay@gmail.com>

Add pkttype support for all families of tables.

Joint work with Álvaro Neira Ayuso <alvaroneay@gmail.com>

Signed-off-by: Alvaro Neira Ayuso <alvaroneay@gmail.com>
Signed-off-by: Ana Rey <anarey@gmail.com>
---

[Changes in v3:]
* Add support for NFPROTO_INET when handing the loopback case.
(NFPROTO_BRIDGE and NFPROTO_ARP families do not make sense when
handing the loopback case)

* Delete the broadcast case when handing the lookback case. This does not make
sense.

* Fix the description of NFT_META_PKTTYPE key.

[Changes in v2]
Put "case NFT_META_PKTTYPE:" outside of the #ifdef CONFIG_NETWORK_SECMARK.
It was a mistake.
Thanks to Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com> for
reporting this mistake.




 include/uapi/linux/netfilter/nf_tables.h |    2 ++
 net/netfilter/nft_meta.c                 |   34 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 801bdd1..72ad208 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -571,6 +571,7 @@ enum nft_exthdr_attributes {
  * @NFT_META_L4PROTO: layer 4 protocol number
  * @NFT_META_BRI_IIFNAME: packet input bridge interface name
  * @NFT_META_BRI_OIFNAME: packet output bridge interface name
+ * @NFT_META_PKTTYPE: Packet type
  */
 enum nft_meta_keys {
 	NFT_META_LEN,
@@ -592,6 +593,7 @@ enum nft_meta_keys {
 	NFT_META_L4PROTO,
 	NFT_META_BRI_IIFNAME,
 	NFT_META_BRI_OIFNAME,
+	NFT_META_PKTTYPE,
 };
 
 /**
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 852b178..c46d9ac 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -14,6 +14,9 @@
 #include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
 #include <net/dst.h>
 #include <net/sock.h>
 #include <net/tcp_states.h> /* for TCP_TIME_WAIT */
@@ -124,6 +127,36 @@ void nft_meta_get_eval(const struct nft_expr *expr,
 		dest->data[0] = skb->secmark;
 		break;
 #endif
+	case NFT_META_PKTTYPE:
+		if (skb->pkt_type != PACKET_LOOPBACK) {
+			dest->data[0] = skb->pkt_type;
+			break;
+		}
+
+		switch (pkt->ops->pf) {
+		case NFPROTO_IPV4:
+			if (ipv4_is_multicast(ip_hdr(skb)->daddr))
+				dest->data[0] = PACKET_MULTICAST;
+			else
+				dest->data[0] = PACKET_HOST;
+			break;
+		case NFPROTO_IPV6:
+			if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
+				dest->data[0] = PACKET_MULTICAST;
+			else
+				dest->data[0] = PACKET_HOST;
+			break;
+		case NFPROTO_INET:
+			if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF ||
+			    ipv4_is_multicast(ip_hdr(skb)->daddr))
+				dest->data[0] = PACKET_MULTICAST;
+			else
+				dest->data[0] = PACKET_HOST;
+			break;
+		default:
+			goto err;
+		}
+		break;
 	default:
 		WARN_ON(1);
 		goto err;
@@ -195,6 +228,7 @@ int nft_meta_get_init(const struct nft_ctx *ctx,
 #ifdef CONFIG_NETWORK_SECMARK
 	case NFT_META_SECMARK:
 #endif
+	case NFT_META_PKTTYPE:
 		break;
 	default:
 		return -EOPNOTSUPP;
-- 
1.7.10.4

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