netfilter: nat: merge ipv4/ipv6 masquerade code into main nat module

Instead of using extra modules for these, turn the config options into
an implicit dependency that adds masq feature to the protocol specific nf_nat module.

before:
   text    data     bss     dec     hex filename
   2001     860       4    2865     b31 net/ipv4/netfilter/nf_nat_masquerade_ipv4.ko
   5579     780       2    6361    18d9 net/ipv4/netfilter/nf_nat_ipv4.ko
   2860     836       8    3704     e78 net/ipv6/netfilter/nf_nat_masquerade_ipv6.ko
   6648     780       2    7430    1d06 net/ipv6/netfilter/nf_nat_ipv6.ko

after:
   text    data     bss     dec     hex filename
   7245     872       8    8125    1fbd net/ipv4/netfilter/nf_nat_ipv4.ko
   9165     848      12   10025    2729 net/ipv6/netfilter/nf_nat_ipv6.ko

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/Kconfig

@@ -129,10 +129,7 @@ config NFT_CHAIN_NAT_IPV4
 	  source and destination ports.
 
 config NF_NAT_MASQUERADE_IPV4
-	tristate "IPv4 masquerade support"
-	help
-	  This is the kernel functionality to provide NAT in the masquerade
-	  flavour (automatic source address selection).
+	bool
 
 config NFT_MASQ_IPV4
 	tristate "IPv4 masquerading support for nf_tables"

net/ipv4/netfilter/Makefile

@@ -10,6 +10,7 @@ nf_conntrack_ipv4-y	:=  nf_conntrack_l3proto_ipv4.o nf_conntrack_proto_icmp.o
 obj-$(CONFIG_NF_CONNTRACK_IPV4) += nf_conntrack_ipv4.o
 
 nf_nat_ipv4-y		:= nf_nat_l3proto_ipv4.o nf_nat_proto_icmp.o
+nf_nat_ipv4-$(CONFIG_NF_NAT_MASQUERADE_IPV4) += nf_nat_masquerade_ipv4.o
 obj-$(CONFIG_NF_NAT_IPV4) += nf_nat_ipv4.o
 
 # defrag
@@ -32,9 +33,6 @@ nf_nat_snmp_basic-y := nf_nat_snmp_basic.asn1.o nf_nat_snmp_basic_main.o
 $(obj)/nf_nat_snmp_basic_main.o: $(obj)/nf_nat_snmp_basic.asn1.h
 obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
 
-obj-$(CONFIG_NF_NAT_MASQUERADE_IPV4) += nf_nat_masquerade_ipv4.o
-
-
 # NAT protocols (nf_nat)
 obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
 

net/ipv4/netfilter/nf_nat_masquerade_ipv4.c

@@ -7,7 +7,6 @@
  */
 
 #include <linux/types.h>
-#include <linux/module.h>
 #include <linux/atomic.h>
 #include <linux/inetdevice.h>
 #include <linux/ip.h>
@@ -157,6 +156,3 @@ void nf_nat_masquerade_ipv4_unregister_notifier(void)
 	unregister_inetaddr_notifier(&masq_inet_notifier);
 }
 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");

net/ipv6/netfilter/Kconfig

@@ -136,10 +136,7 @@ config NF_NAT_IPV6
 if NF_NAT_IPV6
 
 config NF_NAT_MASQUERADE_IPV6
-	tristate "IPv6 masquerade support"
-	help
-	  This is the kernel functionality to provide NAT in the masquerade
-	  flavour (automatic source address selection) for IPv6.
+	bool
 
 endif # NF_NAT_IPV6
 

net/ipv6/netfilter/Makefile

@@ -18,8 +18,8 @@ nf_conntrack_ipv6-y  :=  nf_conntrack_l3proto_ipv6.o nf_conntrack_proto_icmpv6.o
 obj-$(CONFIG_NF_CONNTRACK_IPV6) += nf_conntrack_ipv6.o
 
 nf_nat_ipv6-y		:= nf_nat_l3proto_ipv6.o nf_nat_proto_icmpv6.o
+nf_nat_ipv6-$(CONFIG_NF_NAT_MASQUERADE_IPV6) += nf_nat_masquerade_ipv6.o
 obj-$(CONFIG_NF_NAT_IPV6) += nf_nat_ipv6.o
-obj-$(CONFIG_NF_NAT_MASQUERADE_IPV6) += nf_nat_masquerade_ipv6.o
 
 # defrag
 nf_defrag_ipv6-y := nf_defrag_ipv6_hooks.o nf_conntrack_reasm.o

net/ipv6/netfilter/nf_nat_masquerade_ipv6.c

@@ -10,7 +10,6 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/module.h>
 #include <linux/atomic.h>
 #include <linux/netdevice.h>
 #include <linux/ipv6.h>
@@ -186,6 +185,3 @@ void nf_nat_masquerade_ipv6_unregister_notifier(void)
 	unregister_netdevice_notifier(&masq_dev_notifier);
 }
 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");