netfilter: audit target to record accepted/dropped packets

This patch adds a new netfilter target which creates audit records
for packets traversing a certain chain.

It can be used to record packets which are rejected administraively
as follows:

  -N AUDIT_DROP
  -A AUDIT_DROP -j AUDIT --type DROP
  -A AUDIT_DROP -j DROP

a rule which would typically drop or reject a packet would then
invoke the new chain to record packets before dropping them.

  -j AUDIT_DROP

The module is protocol independant and works for iptables, ip6tables
and ebtables.

The following information is logged:
 - netfilter hook
 - packet length
 - incomming/outgoing interface
 - MAC src/dst/proto for ethernet packets
 - src/dst/protocol address for IPv4/IPv6
 - src/dst port for TCP/UDP/UDPLITE
 - icmp type/code

Cc: Patrick McHardy <kaber@trash.net>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Thomas Graf <tgraf@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 1b79353a5d29..93918f022555 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -326,6 +326,16 @@ config NETFILTER_XT_CONNMARK
 
 comment "Xtables targets"
 
+config NETFILTER_XT_TARGET_AUDIT
+	tristate "AUDIT target support"
+	depends on AUDIT
+	depends on NETFILTER_ADVANCED
+	---help---
+	  This option adds a 'AUDIT' target, which can be used to create
+	  audit records for packets dropped/accepted.
+
+	  To compileit as a module, choose M here. If unsure, say N.
+
 config NETFILTER_XT_TARGET_CHECKSUM
 	tristate "CHECKSUM target support"
 	depends on IP_NF_MANGLE || IP6_NF_MANGLE