[NETFILTER]: nf_nat: add SNMP NAT helper port

Add nf_conntrack port of the SNMP NAT helper.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter/Kconfig

@@ -477,6 +477,21 @@ config IP_NF_NAT_SNMP_BASIC
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config NF_NAT_SNMP_BASIC
+	tristate "Basic SNMP-ALG support (EXPERIMENTAL)"
+	depends on EXPERIMENTAL && NF_NAT
+	---help---
+
+	  This module implements an Application Layer Gateway (ALG) for
+	  SNMP payloads.  In conjunction with NAT, it allows a network
+	  management system to access multiple private networks with
+	  conflicting addresses.  It works by modifying IP addresses
+	  inside SNMP payloads to match IP-layer NAT mapping.
+
+	  This is the "basic" form of SNMP-ALG, as described in RFC 2962
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 # If they want FTP, set to $CONFIG_IP_NF_NAT (m or y),
 # or $CONFIG_IP_NF_FTP (m or y), whichever is weaker.
 # From kconfig-language.txt:

net/ipv4/netfilter/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
 obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
 obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
 obj-$(CONFIG_NF_NAT_SIP) += nf_nat_sip.o
+obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
 obj-$(CONFIG_NF_NAT_TFTP) += nf_nat_tftp.o
 
 # NAT protocols (nf_nat)