Commit f169fd69 authored Jan 07, 2017 by Liping Zhang Committed by Pablo Neira Ayuso Jan 18, 2017

netfilter: nft_meta: deal with PACKET_LOOPBACK in netdev family



After adding the following nft rule, then ping 224.0.0.1:
  # nft add rule netdev t c pkttype host counter

The warning complain message will be printed out again and again:
  WARNING: CPU: 0 PID: 10182 at net/netfilter/nft_meta.c:163 \
           nft_meta_get_eval+0x3fe/0x460 [nft_meta]
  [...]
  Call Trace:
  <IRQ>
  dump_stack+0x85/0xc2
  __warn+0xcb/0xf0
  warn_slowpath_null+0x1d/0x20
  nft_meta_get_eval+0x3fe/0x460 [nft_meta]
  nft_do_chain+0xff/0x5e0 [nf_tables]

So we should deal with PACKET_LOOPBACK in netdev family too. For ipv4,
convert it to PACKET_BROADCAST/MULTICAST according to the destination
address's type; For ipv6, convert it to PACKET_MULTICAST directly.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

parent 9a6d8762

net/netfilter/nft_meta.c

+27 −1

Original line number	Diff line number	Diff line
		@@ -156,8 +156,34 @@ void nft_meta_get_eval(const struct nft_expr *expr,
		case NFPROTO_IPV6:
		*dest = PACKET_MULTICAST;
		break;
		case NFPROTO_NETDEV:
		switch (skb->protocol) {
		case htons(ETH_P_IP): {
		int noff = skb_network_offset(skb);
		struct iphdr *iph, _iph;

		iph = skb_header_pointer(skb, noff,
		sizeof(_iph), &_iph);
		if (!iph)
		goto err;

		if (ipv4_is_multicast(iph->daddr))
		*dest = PACKET_MULTICAST;
		else
		*dest = PACKET_BROADCAST;

		break;
		}
		case htons(ETH_P_IPV6):
		*dest = PACKET_MULTICAST;
		break;
		default:
		WARN_ON(1);
		WARN_ON_ONCE(1);
		goto err;
		}
		break;
		default:
		WARN_ON_ONCE(1);
		goto err;
		}
		break;

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