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Commit e2a093ff authored by Ana Rey's avatar Ana Rey Committed by Pablo Neira Ayuso
Browse files

netfilter: nft_meta: add pkttype support 



Add pkttype support for ip, ipv6 and inet families of tables.

This allows you to fetch the meta packet type based on the link layer
information. The loopback traffic is a special case, the packet type
is guessed from the network layer header.

No special handling for bridge and arp since we're not going to see
such traffic in the loopback interface.

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

Signed-off-by: default avatarAlvaro Neira Ayuso <alvaroneay@gmail.com>
Signed-off-by: default avatarAna Rey <anarey@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent e91ded8d

include/uapi/linux/netfilter/nf_tables.h

+2 −0
Original line number Diff line number Diff line
@@ -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 (skb->pkt_type), special handling for loopback

 */

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,

};



/**

net/netfilter/nft_meta.c

+28 −0
Original line number Diff line number Diff line
@@ -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 +127,30 @@ 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_BROADCAST;

			break;

		case NFPROTO_IPV6:

			if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)

				dest->data[0] = PACKET_MULTICAST;

			else

				dest->data[0] = PACKET_BROADCAST;

			break;

		default:

			WARN_ON(1);

			goto err;

		}

		break;

	default:

		WARN_ON(1);

		goto err;
@@ -195,6 +222,7 @@ 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;