netfilter: xtables: merge xt_MARK into xt_mark

Two arguments for combining the two:
- xt_mark is pretty useless without xt_MARK
- the actual code is so small anyway that the kmod metadata and the module
  in its loaded state totally outweighs the combined actual code size.

i586-before:
-rw-r--r-- 1 jengelh users 3821 Feb 10 01:01 xt_MARK.ko
-rw-r--r-- 1 jengelh users 2592 Feb 10 00:04 xt_MARK.o
-rw-r--r-- 1 jengelh users 3274 Feb 10 01:01 xt_mark.ko
-rw-r--r-- 1 jengelh users 2108 Feb 10 00:05 xt_mark.o
   text    data     bss     dec     hex filename
    354     264       0     618     26a xt_MARK.o
    223     176       0     399     18f xt_mark.o
And the runtime size is like 14 KB.

i586-after:
-rw-r--r-- 1 jengelh users 3264 Feb 18 17:28 xt_mark.o

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

include/linux/netfilter/xt_MARK.h

@@ -1,10 +1,6 @@
 #ifndef _XT_MARK_H_target
 #define _XT_MARK_H_target
 
-#include <linux/types.h>
-
-struct xt_mark_tginfo2 {
-	__u32 mark, mask;
-};
+#include <linux/netfilter/xt_mark.h>
 
 #endif /*_XT_MARK_H_target */

include/linux/netfilter/xt_mark.h

@@ -3,6 +3,10 @@
 
 #include <linux/types.h>
 
+struct xt_mark_tginfo2 {
+	__u32 mark, mask;
+};
+
 struct xt_mark_mtinfo1 {
 	__u32 mark, mask;
 	__u8 invert;

net/netfilter/Kconfig

@@ -314,6 +314,23 @@ config NETFILTER_XTABLES
 
 if NETFILTER_XTABLES
 
+comment "Xtables combined modules"
+
+config NETFILTER_XT_MARK
+	tristate 'nfmark target and match support'
+	default m if NETFILTER_ADVANCED=n
+	---help---
+	This option adds the "MARK" target and "mark" match.
+
+	Netfilter mark matching allows you to match packets based on the
+	"nfmark" value in the packet.
+	The target allows you to create rules in the "mangle" table which alter
+	the netfilter mark (nfmark) field associated with the packet.
+
+	Prior to routing, the nfmark can influence the routing method (see
+	"Use netfilter MARK value as routing key") and can also be used by
+	other subsystems to change their behavior.
+
 # alphabetically ordered list of targets
 
 comment "Xtables targets"
@@ -425,16 +442,12 @@ config NETFILTER_XT_TARGET_LED
 
 config NETFILTER_XT_TARGET_MARK
 	tristate '"MARK" target support'
-	default m if NETFILTER_ADVANCED=n
-	help
-	  This option adds a `MARK' target, which allows you to create rules
-	  in the `mangle' table which alter the netfilter mark (nfmark) field
-	  associated with the packet prior to routing. This can change
-	  the routing method (see `Use netfilter MARK value as routing
-	  key') and can also be used by other subsystems to change their
-	  behavior.
-
-	  To compile it as a module, choose M here.  If unsure, say N.
+	depends on NETFILTER_ADVANCED
+	select NETFILTER_XT_MARK
+	---help---
+	This is a backwards-compat option for the user's convenience
+	(e.g. when running oldconfig). It selects
+	CONFIG_NETFILTER_XT_MARK (combined mark/MARK module).
 
 config NETFILTER_XT_TARGET_NFLOG
 	tristate '"NFLOG" target support'
@@ -739,13 +752,12 @@ config NETFILTER_XT_MATCH_MAC
 
 config NETFILTER_XT_MATCH_MARK
 	tristate '"mark" match support'
-	default m if NETFILTER_ADVANCED=n
-	help
-	  Netfilter mark matching allows you to match packets based on the
-	  `nfmark' value in the packet.  This can be set by the MARK target
-	  (see below).
-
-	  To compile it as a module, choose M here.  If unsure, say N.
+	depends on NETFILTER_ADVANCED
+	select NETFILTER_XT_MARK
+	---help---
+	This is a backwards-compat option for the user's convenience
+	(e.g. when running oldconfig). It selects
+	CONFIG_NETFILTER_XT_MARK (combined mark/MARK module).
 
 config NETFILTER_XT_MATCH_MULTIPORT
 	tristate '"multiport" Multiple port match support'

net/netfilter/Makefile

@@ -40,6 +40,9 @@ obj-$(CONFIG_NETFILTER_TPROXY) += nf_tproxy_core.o
 # generic X tables 
 obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
 
+# combos
+obj-$(CONFIG_NETFILTER_XT_MARK) += xt_mark.o
+
 # targets
 obj-$(CONFIG_NETFILTER_XT_TARGET_CLASSIFY) += xt_CLASSIFY.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_CONNMARK) += xt_CONNMARK.o
@@ -48,7 +51,6 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_CT) += xt_CT.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_DSCP) += xt_DSCP.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_HL) += xt_HL.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_LED) += xt_LED.o
-obj-$(CONFIG_NETFILTER_XT_TARGET_MARK) += xt_MARK.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_NFLOG) += xt_NFLOG.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_NFQUEUE) += xt_NFQUEUE.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_NOTRACK) += xt_NOTRACK.o
@@ -76,7 +78,6 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_IPRANGE) += xt_iprange.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LENGTH) += xt_length.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LIMIT) += xt_limit.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_MAC) += xt_mac.o
-obj-$(CONFIG_NETFILTER_XT_MATCH_MARK) += xt_mark.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_MULTIPORT) += xt_multiport.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_OSF) += xt_osf.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_OWNER) += xt_owner.o

net/netfilter/xt_mark.c

@@ -18,9 +18,20 @@
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
-MODULE_DESCRIPTION("Xtables: packet mark match");
+MODULE_DESCRIPTION("Xtables: packet mark operations");
 MODULE_ALIAS("ipt_mark");
 MODULE_ALIAS("ip6t_mark");
+MODULE_ALIAS("ipt_MARK");
+MODULE_ALIAS("ip6t_MARK");
+
+static unsigned int
+mark_tg(struct sk_buff *skb, const struct xt_target_param *par)
+{
+	const struct xt_mark_tginfo2 *info = par->targinfo;
+
+	skb->mark = (skb->mark & ~info->mask) ^ info->mark;
+	return XT_CONTINUE;
+}
 
 static bool
 mark_mt(const struct sk_buff *skb, const struct xt_match_param *par)
@@ -30,6 +41,15 @@ mark_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	return ((skb->mark & info->mask) == info->mark) ^ info->invert;
 }
 
+static struct xt_target mark_tg_reg __read_mostly = {
+	.name           = "MARK",
+	.revision       = 2,
+	.family         = NFPROTO_UNSPEC,
+	.target         = mark_tg,
+	.targetsize     = sizeof(struct xt_mark_tginfo2),
+	.me             = THIS_MODULE,
+};
+
 static struct xt_match mark_mt_reg __read_mostly = {
 	.name           = "mark",
 	.revision       = 1,
@@ -41,12 +61,23 @@ static struct xt_match mark_mt_reg __read_mostly = {
 
 static int __init mark_mt_init(void)
 {
-	return xt_register_match(&mark_mt_reg);
+	int ret;
+
+	ret = xt_register_target(&mark_tg_reg);
+	if (ret < 0)
+		return ret;
+	ret = xt_register_match(&mark_mt_reg);
+	if (ret < 0) {
+		xt_unregister_target(&mark_tg_reg);
+		return ret;
+	}
+	return 0;
 }
 
 static void __exit mark_mt_exit(void)
 {
 	xt_unregister_match(&mark_mt_reg);
+	xt_unregister_target(&mark_tg_reg);
 }
 
 module_init(mark_mt_init);