[NETFILTER]: x_tables: unify IPv4/IPv6 esp match

This unifies ipt_esp and ip6t_esp to xt_esp. Please note that now
a user program needs to specify IPPROTO_ESP as protocol to use esp match
with IPv6. This means that ip6tables requires '-p esp' like iptables.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/xt_esp.h

@@ -0,0 +1,14 @@
+#ifndef _XT_ESP_H
+#define _XT_ESP_H
+
+struct xt_esp
+{
+	u_int32_t spis[2];	/* Security Parameter Index */
+	u_int8_t  invflags;	/* Inverse flags */
+};
+
+/* Values for "invflags" field in struct xt_esp. */
+#define XT_ESP_INV_SPI	0x01	/* Invert the sense of spi. */
+#define XT_ESP_INV_MASK	0x01	/* All possible flags. */
+
+#endif /*_XT_ESP_H*/

include/linux/netfilter_ipv4/ipt_esp.h

@@ -1,16 +1,10 @@
 #ifndef _IPT_ESP_H
 #define _IPT_ESP_H
 
-struct ipt_esp
+#include <linux/netfilter/xt_esp.h>
-{
-	u_int32_t spis[2];			/* Security Parameter Index */
-	u_int8_t  invflags;			/* Inverse flags */
-};
 
-
+#define ipt_esp xt_esp
-
+#define IPT_ESP_INV_SPI		XT_ESP_INV_SPI
-/* Values for "invflags" field in struct ipt_esp. */
+#define IPT_ESP_INV_MASK	XT_ESP_INV_MASK
-#define IPT_ESP_INV_SPI		0x01	/* Invert the sense of spi. */
-#define IPT_ESP_INV_MASK	0x01	/* All possible flags. */
 
 #endif /*_IPT_ESP_H*/

include/linux/netfilter_ipv6/ip6t_esp.h

@@ -1,14 +1,10 @@
 #ifndef _IP6T_ESP_H
 #define _IP6T_ESP_H
 
-struct ip6t_esp
+#include <linux/netfilter/xt_esp.h>
-{
-	u_int32_t spis[2];			/* Security Parameter Index */
-	u_int8_t  invflags;			/* Inverse flags */
-};
 
-/* Values for "invflags" field in struct ip6t_esp. */
+#define ip6t_esp xt_esp
-#define IP6T_ESP_INV_SPI		0x01	/* Invert the sense of spi. */
+#define IP6T_ESP_INV_SPI	XT_ESP_INV_SPI
-#define IP6T_ESP_INV_MASK	0x01	/* All possible flags. */
+#define IP6T_ESP_INV_MASK	XT_ESP_INV_MASK
 
 #endif /*_IP6T_ESP_H*/

net/ipv4/netfilter/Kconfig

@@ -272,12 +272,12 @@ config IP_NF_MATCH_DSCP
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
-config IP_NF_MATCH_AH_ESP
+config IP_NF_MATCH_AH
-	tristate "AH/ESP match support"
+	tristate "AH match support"
 	depends on IP_NF_IPTABLES
 	help
-	  These two match extensions (`ah' and `esp') allow you to match a
+	  This match extension allows you to match a range of SPIs
-	  range of SPIs inside AH or ESP headers of IPSec packets.
+	  inside AH header of IPSec packets.
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 

net/ipv4/netfilter/Makefile

@@ -59,7 +59,7 @@ obj-$(CONFIG_IP_NF_MATCH_TOS) += ipt_tos.o
 obj-$(CONFIG_IP_NF_MATCH_RECENT) += ipt_recent.o
 obj-$(CONFIG_IP_NF_MATCH_ECN) += ipt_ecn.o
 obj-$(CONFIG_IP_NF_MATCH_DSCP) += ipt_dscp.o
-obj-$(CONFIG_IP_NF_MATCH_AH_ESP) += ipt_ah.o ipt_esp.o
+obj-$(CONFIG_IP_NF_MATCH_AH) += ipt_ah.o
 obj-$(CONFIG_IP_NF_MATCH_TTL) += ipt_ttl.o
 obj-$(CONFIG_IP_NF_MATCH_ADDRTYPE) += ipt_addrtype.o
 

net/ipv6/netfilter/Kconfig

@@ -115,11 +115,11 @@ config IP6_NF_MATCH_IPV6HEADER
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
-config IP6_NF_MATCH_AHESP
+config IP6_NF_MATCH_AH
-	tristate "AH/ESP match support"
+	tristate "AH match support"
 	depends on IP6_NF_IPTABLES
 	help
-	  This module allows one to match AH and ESP packets.
+	  This module allows one to match AH packets.
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 

net/ipv6/netfilter/Makefile

@@ -8,7 +8,7 @@ obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o
 obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o ip6t_dst.o
 obj-$(CONFIG_IP6_NF_MATCH_IPV6HEADER) += ip6t_ipv6header.o
 obj-$(CONFIG_IP6_NF_MATCH_FRAG) += ip6t_frag.o
-obj-$(CONFIG_IP6_NF_MATCH_AHESP) += ip6t_esp.o ip6t_ah.o
+obj-$(CONFIG_IP6_NF_MATCH_AH) += ip6t_ah.o
 obj-$(CONFIG_IP6_NF_MATCH_EUI64) += ip6t_eui64.o
 obj-$(CONFIG_IP6_NF_MATCH_MULTIPORT) += ip6t_multiport.o
 obj-$(CONFIG_IP6_NF_MATCH_OWNER) += ip6t_owner.o

net/ipv6/netfilter/ip6t_esp.c

@@ -1,115 +0,0 @@
-/* Kernel module to match ESP parameters. */
-/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-
-#include <linux/module.h>
-#include <linux/skbuff.h>
-#include <linux/ip.h>
-#include <linux/ipv6.h>
-#include <linux/types.h>
-#include <net/checksum.h>
-#include <net/ipv6.h>
-
-#include <linux/netfilter_ipv6/ip6_tables.h>
-#include <linux/netfilter_ipv6/ip6t_esp.h>
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("IPv6 ESP match");
-MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
-
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(format, args...)
-#endif
-
-/* Returns 1 if the spi is matched by the range, 0 otherwise */
-static inline int
-spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
-{
-	int r=0;
-	DEBUGP("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
-	       min,spi,max);
-	r=(spi >= min && spi <= max) ^ invert;
-	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
-	return r;
-}
-
-static int
-match(const struct sk_buff *skb,
-      const struct net_device *in,
-      const struct net_device *out,
-      const struct xt_match *match,
-      const void *matchinfo,
-      int offset,
-      unsigned int protoff,
-      int *hotdrop)
-{
-	struct ip_esp_hdr _esp, *eh;
-	const struct ip6t_esp *espinfo = matchinfo;
-	unsigned int ptr;
-
-	/* Make sure this isn't an evil packet */
-	/*DEBUGP("ipv6_esp entered \n");*/
-
-	if (ipv6_find_hdr(skb, &ptr, NEXTHDR_ESP, NULL) < 0)
-		return 0;
-
-	eh = skb_header_pointer(skb, ptr, sizeof(_esp), &_esp);
-	if (eh == NULL) {
-		*hotdrop = 1;
-		return 0;
-	}
-
-	DEBUGP("IPv6 ESP SPI %u %08X\n", ntohl(eh->spi), ntohl(eh->spi));
-
-	return (eh != NULL)
-		&& spi_match(espinfo->spis[0], espinfo->spis[1],
-			      ntohl(eh->spi),
-			      !!(espinfo->invflags & IP6T_ESP_INV_SPI));
-}
-
-/* Called when user tries to insert an entry of this type. */
-static int
-checkentry(const char *tablename,
-	   const void *ip,
-	   const struct xt_match *match,
-	   void *matchinfo,
-	   unsigned int matchinfosize,
-	   unsigned int hook_mask)
-{
-	const struct ip6t_esp *espinfo = matchinfo;
-
-	if (espinfo->invflags & ~IP6T_ESP_INV_MASK) {
-		DEBUGP("ip6t_esp: unknown flags %X\n",
-			 espinfo->invflags);
-		return 0;
-	}
-	return 1;
-}
-
-static struct ip6t_match esp_match = {
-	.name		= "esp",
-	.match		= match,
-	.matchsize	= sizeof(struct ip6t_esp),
-	.checkentry	= checkentry,
-	.me		= THIS_MODULE,
-};
-
-static int __init ip6t_esp_init(void)
-{
-	return ip6t_register_match(&esp_match);
-}
-
-static void __exit ip6t_esp_fini(void)
-{
-	ip6t_unregister_match(&esp_match);
-}
-
-module_init(ip6t_esp_init);
-module_exit(ip6t_esp_fini);

net/netfilter/Kconfig

@@ -231,6 +231,15 @@ config NETFILTER_XT_MATCH_DCCP
 	  If you want to compile it as a module, say M here and read
 	  <file:Documentation/modules.txt>.  If unsure, say `N'.
 
+config NETFILTER_XT_MATCH_ESP
+	tristate '"ESP" match support'
+	depends on NETFILTER_XTABLES
+	help
+	  This match extension allows you to match a range of SPIs
+	  inside ESP header of IPSec packets.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_MATCH_HELPER
 	tristate '"helper" match support'
 	depends on NETFILTER_XTABLES

net/netfilter/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_CONNBYTES) += xt_connbytes.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_CONNMARK) += xt_connmark.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_CONNTRACK) += xt_conntrack.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_DCCP) += xt_dccp.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_ESP) += xt_esp.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_HELPER) += xt_helper.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LENGTH) += xt_length.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_LIMIT) += xt_limit.o

net/netfilter/xt_esp.c

@@ -9,16 +9,22 @@
 
 #include <linux/module.h>
 #include <linux/skbuff.h>
+#include <linux/in.h>
 #include <linux/ip.h>
 
-#include <linux/netfilter_ipv4/ipt_esp.h>
+#include <linux/netfilter/xt_esp.h>
+#include <linux/netfilter/x_tables.h>
+
 #include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
-MODULE_DESCRIPTION("iptables ESP SPI match module");
+MODULE_DESCRIPTION("x_tables ESP SPI match module");
+MODULE_ALIAS("ipt_esp");
+MODULE_ALIAS("ip6t_esp");
 
-#ifdef DEBUG_CONNTRACK
+#if 0
 #define duprintf(format, args...) printk(format , ## args)
 #else
 #define duprintf(format, args...)
@@ -28,11 +34,11 @@ MODULE_DESCRIPTION("iptables ESP SPI match module");
 static inline int
 spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
 {
-	int r=0;
+	int r = 0;
-        duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
+	duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x", invert ? '!' : ' ',
-        	min,spi,max);
+		 min, spi, max);
-	r=(spi >= min && spi <= max) ^ invert;
+	r = (spi >= min && spi <= max) ^ invert;
-	duprintf(" result %s\n",r? "PASS" : "FAILED");
+	duprintf(" result %s\n", r ? "PASS" : "FAILED");
 	return r;
 }
 
@@ -47,14 +53,13 @@ match(const struct sk_buff *skb,
       int *hotdrop)
 {
 	struct ip_esp_hdr _esp, *eh;
-	const struct ipt_esp *espinfo = matchinfo;
+	const struct xt_esp *espinfo = matchinfo;
 
 	/* Must not be a fragment. */
 	if (offset)
 		return 0;
 
-	eh = skb_header_pointer(skb, protoff,
+	eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp);
-				sizeof(_esp), &_esp);
 	if (eh == NULL) {
 		/* We've been asked to examine this packet, and we
 		 * can't.  Hence, no choice but to drop.
@@ -64,9 +69,8 @@ match(const struct sk_buff *skb,
 		return 0;
 	}
 
-	return spi_match(espinfo->spis[0], espinfo->spis[1],
+	return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi),
-			 ntohl(eh->spi),
+			 !!(espinfo->invflags & XT_ESP_INV_SPI));
-			 !!(espinfo->invflags & IPT_ESP_INV_SPI));
 }
 
 /* Called when user tries to insert an entry of this type. */
@@ -78,34 +82,55 @@ checkentry(const char *tablename,
 	   unsigned int matchinfosize,
 	   unsigned int hook_mask)
 {
-	const struct ipt_esp *espinfo = matchinfo;
+	const struct xt_esp *espinfo = matchinfo;
 
-	/* Must specify no unknown invflags */
+	if (espinfo->invflags & ~XT_ESP_INV_MASK) {
-	if (espinfo->invflags & ~IPT_ESP_INV_MASK) {
+		duprintf("xt_esp: unknown flags %X\n", espinfo->invflags);
-		duprintf("ipt_esp: unknown flags %X\n", espinfo->invflags);
 		return 0;
 	}
+
 	return 1;
 }
 
-static struct ipt_match esp_match = {
+static struct xt_match esp_match = {
 	.name		= "esp",
-	.match		= match,
+	.family		= AF_INET,
-	.matchsize	= sizeof(struct ipt_esp),
 	.proto		= IPPROTO_ESP,
-	.checkentry	= checkentry,
+	.match		= &match,
+	.matchsize	= sizeof(struct xt_esp),
+	.checkentry	= &checkentry,
 	.me		= THIS_MODULE,
 };
 
-static int __init ipt_esp_init(void)
+static struct xt_match esp6_match = {
+	.name		= "esp",
+	.family		= AF_INET6,
+	.proto		= IPPROTO_ESP,
+	.match		= &match,
+	.matchsize	= sizeof(struct xt_esp),
+	.checkentry	= &checkentry,
+	.me		= THIS_MODULE,
+};
+
+static int __init xt_esp_init(void)
 {
-	return ipt_register_match(&esp_match);
+	int ret;
+	ret = xt_register_match(&esp_match);
+	if (ret)
+		return ret;
+
+	ret = xt_register_match(&esp6_match);
+	if (ret)
+		xt_unregister_match(&esp_match);
+
+	return ret;
 }
 
-static void __exit ipt_esp_fini(void)
+static void __exit xt_esp_cleanup(void)
 {
-	ipt_unregister_match(&esp_match);
+	xt_unregister_match(&esp_match);
+	xt_unregister_match(&esp6_match);
 }
 
-module_init(ipt_esp_init);
+module_init(xt_esp_init);
-module_exit(ipt_esp_fini);
+module_exit(xt_esp_cleanup);