From 676cf8a61ed240d0a86d471ef419f45ba35dba80 Mon Sep 17 00:00:00 2001

From: Denis Ovsienko <infrastation@yandex.ru>

Date: Thu, 5 Dec 2013 14:54:14 +0400

Subject: [PATCH] NFLOG: don't crash trying to filter at link layer

Before:

@ tcpdump -i nflog icmp

tcpdump: WARNING: SIOCGIFADDR: nflog: No such device

Aborted (core dumped)

After:

@ tcpdump -i nflog icmp

tcpdump: WARNING: SIOCGIFADDR: nflog: No such device

tcpdump: NFLOG link-layer type filtering not implemented

---

 gencode.c | 7 +++++++

 1 file changed, 7 insertions(+)

diff --git a/gencode.c b/gencode.c

index 7bb07fb..d58ea30 100644

--- a/gencode.c

+++ b/gencode.c

@@ -3410,6 +3410,13 @@ gen_linktype(proto)

 	case DLT_AX25_KISS:

 		bpf_error("AX.25 link-layer type filtering not implemented");

+

+	case DLT_NFLOG:

+		/* Using the fixed-size NFLOG header it is possible to tell only

+		 * the address family of the packet, other meaningful data is

+		 * either missing or behind TLVs.

+		 */

+		bpf_error("NFLOG link-layer type filtering not implemented");

 	}

 	/*

-- 

1.8.4.2