netfilter: merge ipt_LOG and ip6_LOG into xt_LOG

ipt_LOG and ip6_LOG have a lot of common code, merge them
to reduce duplicate code.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

include/linux/netfilter/Kbuild

@@ -22,6 +22,7 @@ header-y += xt_CT.h
 header-y += xt_DSCP.h
 header-y += xt_IDLETIMER.h
 header-y += xt_LED.h
+header-y += xt_LOG.h
 header-y += xt_MARK.h
 header-y += xt_nfacct.h
 header-y += xt_NFLOG.h

include/linux/netfilter/xt_LOG.h

+#ifndef _XT_LOG_H
+#define _XT_LOG_H
+
+/* make sure not to change this without changing nf_log.h:NF_LOG_* (!) */
+#define XT_LOG_TCPSEQ		0x01	/* Log TCP sequence numbers */
+#define XT_LOG_TCPOPT		0x02	/* Log TCP options */
+#define XT_LOG_IPOPT		0x04	/* Log IP options */
+#define XT_LOG_UID		0x08	/* Log UID owning local socket */
+#define XT_LOG_NFLOG		0x10	/* Unsupported, don't reuse */
+#define XT_LOG_MACDECODE	0x20	/* Decode MAC header */
+#define XT_LOG_MASK		0x2f
+
+struct xt_log_info {
+	unsigned char level;
+	unsigned char logflags;
+	char prefix[30];
+};
+
+#endif /* _XT_LOG_H */

include/linux/netfilter_ipv4/ipt_LOG.h

 #ifndef _IPT_LOG_H
 #define _IPT_LOG_H
 
+#warning "Please update iptables, this file will be removed soon!"
+
 /* make sure not to change this without changing netfilter.h:NF_LOG_* (!) */
 #define IPT_LOG_TCPSEQ		0x01	/* Log TCP sequence numbers */
 #define IPT_LOG_TCPOPT		0x02	/* Log TCP options */

include/linux/netfilter_ipv6/ip6t_LOG.h

 #ifndef _IP6T_LOG_H
 #define _IP6T_LOG_H
 
+#warning "Please update iptables, this file will be removed soon!"
+
 /* make sure not to change this without changing netfilter.h:NF_LOG_* (!) */
 #define IP6T_LOG_TCPSEQ		0x01	/* Log TCP sequence numbers */
 #define IP6T_LOG_TCPOPT		0x02	/* Log TCP options */

net/ipv4/netfilter/Kconfig

@@ -123,15 +123,6 @@ config IP_NF_TARGET_REJECT
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
-config IP_NF_TARGET_LOG
-	tristate "LOG target support"
-	default m if NETFILTER_ADVANCED=n
-	help
-	  This option adds a `LOG' target, which allows you to create rules in
-	  any iptables table which records the packet header to the syslog.
-
-	  To compile it as a module, choose M here.  If unsure, say N.
-
 config IP_NF_TARGET_ULOG
 	tristate "ULOG target support"
 	default m if NETFILTER_ADVANCED=n

net/ipv4/netfilter/Makefile

@@ -54,7 +54,6 @@ obj-$(CONFIG_IP_NF_MATCH_RPFILTER) += ipt_rpfilter.o
 # targets
 obj-$(CONFIG_IP_NF_TARGET_CLUSTERIP) += ipt_CLUSTERIP.o
 obj-$(CONFIG_IP_NF_TARGET_ECN) += ipt_ECN.o
-obj-$(CONFIG_IP_NF_TARGET_LOG) += ipt_LOG.o
 obj-$(CONFIG_IP_NF_TARGET_MASQUERADE) += ipt_MASQUERADE.o
 obj-$(CONFIG_IP_NF_TARGET_NETMAP) += ipt_NETMAP.o
 obj-$(CONFIG_IP_NF_TARGET_REDIRECT) += ipt_REDIRECT.o

net/ipv6/netfilter/Kconfig

@@ -154,15 +154,6 @@ config IP6_NF_TARGET_HL
 	(e.g. when running oldconfig). It selects
 	CONFIG_NETFILTER_XT_TARGET_HL.
 
-config IP6_NF_TARGET_LOG
-	tristate "LOG target support"
-	default m if NETFILTER_ADVANCED=n
-	help
-	  This option adds a `LOG' target, which allows you to create rules in
-	  any iptables table which records the packet header to the syslog.
-
-	  To compile it as a module, choose M here.  If unsure, say N.
-
 config IP6_NF_FILTER
 	tristate "Packet filtering"
 	default m if NETFILTER_ADVANCED=n

net/ipv6/netfilter/Makefile

@@ -31,5 +31,4 @@ obj-$(CONFIG_IP6_NF_MATCH_RPFILTER) += ip6t_rpfilter.o
 obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o
 
 # targets
-obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o
 obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o

net/ipv6/netfilter/ip6t_LOG.c

-/*
- * This is a module which is used for logging packets.
- */
-
-/* (C) 2001 Jan Rekorajski <baggins@pld.org.pl>
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * 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.
- */
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-#include <linux/module.h>
-#include <linux/skbuff.h>
-#include <linux/if_arp.h>
-#include <linux/ip.h>
-#include <linux/spinlock.h>
-#include <linux/icmpv6.h>
-#include <net/udp.h>
-#include <net/tcp.h>
-#include <net/ipv6.h>
-#include <linux/netfilter.h>
-#include <linux/netfilter/x_tables.h>
-#include <linux/netfilter_ipv6/ip6_tables.h>
-#include <net/netfilter/nf_log.h>
-#include <net/netfilter/xt_log.h>
-
-MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
-MODULE_DESCRIPTION("Xtables: IPv6 packet logging to syslog");
-MODULE_LICENSE("GPL");
-
-struct in_device;
-#include <net/route.h>
-#include <linux/netfilter_ipv6/ip6t_LOG.h>
-
-/* One level of recursion won't kill us */
-static void dump_packet(struct sbuff *m,
-			const struct nf_loginfo *info,
-			const struct sk_buff *skb, unsigned int ip6hoff,
-			int recurse)
-{
-	u_int8_t currenthdr;
-	int fragment;
-	struct ipv6hdr _ip6h;
-	const struct ipv6hdr *ih;
-	unsigned int ptr;
-	unsigned int hdrlen = 0;
-	unsigned int logflags;
-
-	if (info->type == NF_LOG_TYPE_LOG)
-		logflags = info->u.log.logflags;
-	else
-		logflags = NF_LOG_MASK;
-
-	ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
-	if (ih == NULL) {
-		sb_add(m, "TRUNCATED");
-		return;
-	}
-
-	/* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
-	sb_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
-
-	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
-	sb_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
-	       ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
-	       (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
-	       ih->hop_limit,
-	       (ntohl(*(__be32 *)ih) & 0x000fffff));
-
-	fragment = 0;
-	ptr = ip6hoff + sizeof(struct ipv6hdr);
-	currenthdr = ih->nexthdr;
-	while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
-		struct ipv6_opt_hdr _hdr;
-		const struct ipv6_opt_hdr *hp;
-
-		hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
-		if (hp == NULL) {
-			sb_add(m, "TRUNCATED");
-			return;
-		}
-
-		/* Max length: 48 "OPT (...) " */
-		if (logflags & IP6T_LOG_IPOPT)
-			sb_add(m, "OPT ( ");
-
-		switch (currenthdr) {
-		case IPPROTO_FRAGMENT: {
-			struct frag_hdr _fhdr;
-			const struct frag_hdr *fh;
-
-			sb_add(m, "FRAG:");
-			fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
-						&_fhdr);
-			if (fh == NULL) {
-				sb_add(m, "TRUNCATED ");
-				return;
-			}
-
-			/* Max length: 6 "65535 " */
-			sb_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
-
-			/* Max length: 11 "INCOMPLETE " */
-			if (fh->frag_off & htons(0x0001))
-				sb_add(m, "INCOMPLETE ");
-
-			sb_add(m, "ID:%08x ", ntohl(fh->identification));
-
-			if (ntohs(fh->frag_off) & 0xFFF8)
-				fragment = 1;
-
-			hdrlen = 8;
-
-			break;
-		}
-		case IPPROTO_DSTOPTS:
-		case IPPROTO_ROUTING:
-		case IPPROTO_HOPOPTS:
-			if (fragment) {
-				if (logflags & IP6T_LOG_IPOPT)
-					sb_add(m, ")");
-				return;
-			}
-			hdrlen = ipv6_optlen(hp);
-			break;
-		/* Max Length */
-		case IPPROTO_AH:
-			if (logflags & IP6T_LOG_IPOPT) {
-				struct ip_auth_hdr _ahdr;
-				const struct ip_auth_hdr *ah;
-
-				/* Max length: 3 "AH " */
-				sb_add(m, "AH ");
-
-				if (fragment) {
-					sb_add(m, ")");
-					return;
-				}
-
-				ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
-							&_ahdr);
-				if (ah == NULL) {
-					/*
-					 * Max length: 26 "INCOMPLETE [65535
-					 *  bytes] )"
-					 */
-					sb_add(m, "INCOMPLETE [%u bytes] )",
-					       skb->len - ptr);
-					return;
-				}
-
-				/* Length: 15 "SPI=0xF1234567 */
-				sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
-
-			}
-
-			hdrlen = (hp->hdrlen+2)<<2;
-			break;
-		case IPPROTO_ESP:
-			if (logflags & IP6T_LOG_IPOPT) {
-				struct ip_esp_hdr _esph;
-				const struct ip_esp_hdr *eh;
-
-				/* Max length: 4 "ESP " */
-				sb_add(m, "ESP ");
-
-				if (fragment) {
-					sb_add(m, ")");
-					return;
-				}
-
-				/*
-				 * Max length: 26 "INCOMPLETE [65535 bytes] )"
-				 */
-				eh = skb_header_pointer(skb, ptr, sizeof(_esph),
-							&_esph);
-				if (eh == NULL) {
-					sb_add(m, "INCOMPLETE [%u bytes] )",
-					       skb->len - ptr);
-					return;
-				}
-
-				/* Length: 16 "SPI=0xF1234567 )" */
-				sb_add(m, "SPI=0x%x )", ntohl(eh->spi) );
-
-			}
-			return;
-		default:
-			/* Max length: 20 "Unknown Ext Hdr 255" */
-			sb_add(m, "Unknown Ext Hdr %u", currenthdr);
-			return;
-		}
-		if (logflags & IP6T_LOG_IPOPT)
-			sb_add(m, ") ");
-
-		currenthdr = hp->nexthdr;
-		ptr += hdrlen;
-	}
-
-	switch (currenthdr) {
-	case IPPROTO_TCP: {
-		struct tcphdr _tcph;
-		const struct tcphdr *th;
-
-		/* Max length: 10 "PROTO=TCP " */
-		sb_add(m, "PROTO=TCP ");
-
-		if (fragment)
-			break;
-
-		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
-		if (th == NULL) {
-			sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
-			return;
-		}
-
-		/* Max length: 20 "SPT=65535 DPT=65535 " */
-		sb_add(m, "SPT=%u DPT=%u ",
-		       ntohs(th->source), ntohs(th->dest));
-		/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
-		if (logflags & IP6T_LOG_TCPSEQ)
-			sb_add(m, "SEQ=%u ACK=%u ",
-			       ntohl(th->seq), ntohl(th->ack_seq));
-		/* Max length: 13 "WINDOW=65535 " */
-		sb_add(m, "WINDOW=%u ", ntohs(th->window));
-		/* Max length: 9 "RES=0x3C " */
-		sb_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
-		/* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
-		if (th->cwr)
-			sb_add(m, "CWR ");
-		if (th->ece)
-			sb_add(m, "ECE ");
-		if (th->urg)
-			sb_add(m, "URG ");
-		if (th->ack)
-			sb_add(m, "ACK ");
-		if (th->psh)
-			sb_add(m, "PSH ");
-		if (th->rst)
-			sb_add(m, "RST ");
-		if (th->syn)
-			sb_add(m, "SYN ");
-		if (th->fin)
-			sb_add(m, "FIN ");
-		/* Max length: 11 "URGP=65535 " */
-		sb_add(m, "URGP=%u ", ntohs(th->urg_ptr));
-
-		if ((logflags & IP6T_LOG_TCPOPT) &&
-		    th->doff * 4 > sizeof(struct tcphdr)) {
-			u_int8_t _opt[60 - sizeof(struct tcphdr)];
-			const u_int8_t *op;
-			unsigned int i;
-			unsigned int optsize = th->doff * 4
-					       - sizeof(struct tcphdr);
-
-			op = skb_header_pointer(skb,
-						ptr + sizeof(struct tcphdr),
-						optsize, _opt);
-			if (op == NULL) {
-				sb_add(m, "OPT (TRUNCATED)");
-				return;
-			}
-
-			/* Max length: 127 "OPT (" 15*4*2chars ") " */
-			sb_add(m, "OPT (");
-			for (i =0; i < optsize; i++)
-				sb_add(m, "%02X", op[i]);
-			sb_add(m, ") ");
-		}
-		break;
-	}
-	case IPPROTO_UDP:
-	case IPPROTO_UDPLITE: {
-		struct udphdr _udph;
-		const struct udphdr *uh;
-
-		if (currenthdr == IPPROTO_UDP)
-			/* Max length: 10 "PROTO=UDP "     */
-			sb_add(m, "PROTO=UDP " );
-		else	/* Max length: 14 "PROTO=UDPLITE " */
-			sb_add(m, "PROTO=UDPLITE ");
-
-		if (fragment)
-			break;
-
-		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
-		if (uh == NULL) {
-			sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
-			return;
-		}
-
-		/* Max length: 20 "SPT=65535 DPT=65535 " */
-		sb_add(m, "SPT=%u DPT=%u LEN=%u ",
-		       ntohs(uh->source), ntohs(uh->dest),
-		       ntohs(uh->len));
-		break;
-	}
-	case IPPROTO_ICMPV6: {
-		struct icmp6hdr _icmp6h;
-		const struct icmp6hdr *ic;
-
-		/* Max length: 13 "PROTO=ICMPv6 " */
-		sb_add(m, "PROTO=ICMPv6 ");
-
-		if (fragment)
-			break;
-
-		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
-		if (ic == NULL) {
-			sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
-			return;
-		}
-
-		/* Max length: 18 "TYPE=255 CODE=255 " */
-		sb_add(m, "TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
-
-		switch (ic->icmp6_type) {
-		case ICMPV6_ECHO_REQUEST:
-		case ICMPV6_ECHO_REPLY:
-			/* Max length: 19 "ID=65535 SEQ=65535 " */
-			sb_add(m, "ID=%u SEQ=%u ",
-				ntohs(ic->icmp6_identifier),
-				ntohs(ic->icmp6_sequence));
-			break;
-		case ICMPV6_MGM_QUERY:
-		case ICMPV6_MGM_REPORT:
-		case ICMPV6_MGM_REDUCTION:
-			break;
-
-		case ICMPV6_PARAMPROB:
-			/* Max length: 17 "POINTER=ffffffff " */
-			sb_add(m, "POINTER=%08x ", ntohl(ic->icmp6_pointer));
-			/* Fall through */
-		case ICMPV6_DEST_UNREACH:
-		case ICMPV6_PKT_TOOBIG:
-		case ICMPV6_TIME_EXCEED:
-			/* Max length: 3+maxlen */
-			if (recurse) {
-				sb_add(m, "[");
-				dump_packet(m, info, skb,
-					    ptr + sizeof(_icmp6h), 0);
-				sb_add(m, "] ");
-			}
-
-			/* Max length: 10 "MTU=65535 " */
-			if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
-				sb_add(m, "MTU=%u ", ntohl(ic->icmp6_mtu));
-		}
-		break;
-	}
-	/* Max length: 10 "PROTO=255 " */
-	default:
-		sb_add(m, "PROTO=%u ", currenthdr);
-	}
-
-	/* Max length: 15 "UID=4294967295 " */
-	if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
-		read_lock_bh(&skb->sk->sk_callback_lock);
-		if (skb->sk->sk_socket && skb->sk->sk_socket->file)
-			sb_add(m, "UID=%u GID=%u ",
-				skb->sk->sk_socket->file->f_cred->fsuid,
-				skb->sk->sk_socket->file->f_cred->fsgid);
-		read_unlock_bh(&skb->sk->sk_callback_lock);
-	}
-
-	/* Max length: 16 "MARK=0xFFFFFFFF " */
-	if (!recurse && skb->mark)
-		sb_add(m, "MARK=0x%x ", skb->mark);
-}
-
-static void dump_mac_header(struct sbuff *m,
-			    const struct nf_loginfo *info,
-			    const struct sk_buff *skb)
-{
-	struct net_device *dev = skb->dev;
-	unsigned int logflags = 0;
-
-	if (info->type == NF_LOG_TYPE_LOG)
-		logflags = info->u.log.logflags;
-
-	if (!(logflags & IP6T_LOG_MACDECODE))
-		goto fallback;
-
-	switch (dev->type) {
-	case ARPHRD_ETHER:
-		sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
-		       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
-		       ntohs(eth_hdr(skb)->h_proto));
-		return;
-	default:
-		break;
-	}
-
-fallback:
-	sb_add(m, "MAC=");
-	if (dev->hard_header_len &&
-	    skb->mac_header != skb->network_header) {
-		const unsigned char *p = skb_mac_header(skb);
-		unsigned int len = dev->hard_header_len;
-		unsigned int i;
-
-		if (dev->type == ARPHRD_SIT &&
-		    (p -= ETH_HLEN) < skb->head)
-			p = NULL;
-
-		if (p != NULL) {
-			sb_add(m, "%02x", *p++);
-			for (i = 1; i < len; i++)
-				sb_add(m, ":%02x", *p++);
-		}
-		sb_add(m, " ");
-
-		if (dev->type == ARPHRD_SIT) {
-			const struct iphdr *iph =
-				(struct iphdr *)skb_mac_header(skb);
-			sb_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr, &iph->daddr);
-		}
-	} else
-		sb_add(m, " ");
-}
-
-static struct nf_loginfo default_loginfo = {
-	.type	= NF_LOG_TYPE_LOG,
-	.u = {
-		.log = {
-			.level	  = 5,
-			.logflags = NF_LOG_MASK,
-		},
-	},
-};
-
-static void
-ip6t_log_packet(u_int8_t pf,
-		unsigned int hooknum,
-		const struct sk_buff *skb,
-		const struct net_device *in,
-		const struct net_device *out,
-		const struct nf_loginfo *loginfo,
-		const char *prefix)
-{
-	struct sbuff *m = sb_open();
-
-	if (!loginfo)
-		loginfo = &default_loginfo;
-
-	sb_add(m, "<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
-	       prefix,
-	       in ? in->name : "",
-	       out ? out->name : "");
-
-	if (in != NULL)
-		dump_mac_header(m, loginfo, skb);
-
-	dump_packet(m, loginfo, skb, skb_network_offset(skb), 1);
-
-	sb_close(m);
-}
-
-static unsigned int
-log_tg6(struct sk_buff *skb, const struct xt_action_param *par)
-{
-	const struct ip6t_log_info *loginfo = par->targinfo;
-	struct nf_loginfo li;
-
-	li.type = NF_LOG_TYPE_LOG;
-	li.u.log.level = loginfo->level;
-	li.u.log.logflags = loginfo->logflags;
-
-	ip6t_log_packet(NFPROTO_IPV6, par->hooknum, skb, par->in, par->out,
-			&li, loginfo->prefix);
-	return XT_CONTINUE;
-}
-
-
-static int log_tg6_check(const struct xt_tgchk_param *par)
-{
-	const struct ip6t_log_info *loginfo = par->targinfo;
-
-	if (loginfo->level >= 8) {
-		pr_debug("level %u >= 8\n", loginfo->level);
-		return -EINVAL;
-	}
-	if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
-		pr_debug("prefix not null-terminated\n");
-		return -EINVAL;
-	}
-	return 0;
-}
-
-static struct xt_target log_tg6_reg __read_mostly = {
-	.name 		= "LOG",
-	.family		= NFPROTO_IPV6,
-	.target 	= log_tg6,
-	.targetsize	= sizeof(struct ip6t_log_info),
-	.checkentry	= log_tg6_check,
-	.me 		= THIS_MODULE,
-};
-
-static struct nf_logger ip6t_logger __read_mostly = {
-	.name		= "ip6t_LOG",
-	.logfn		= &ip6t_log_packet,
-	.me		= THIS_MODULE,
-};
-
-static int __init log_tg6_init(void)
-{
-	int ret;
-
-	ret = xt_register_target(&log_tg6_reg);
-	if (ret < 0)
-		return ret;
-	nf_log_register(NFPROTO_IPV6, &ip6t_logger);
-	return 0;
-}
-
-static void __exit log_tg6_exit(void)
-{
-	nf_log_unregister(&ip6t_logger);
-	xt_unregister_target(&log_tg6_reg);
-}
-
-module_init(log_tg6_init);
-module_exit(log_tg6_exit);

net/netfilter/Kconfig

@@ -524,6 +524,15 @@ config NETFILTER_XT_TARGET_LED
 	  For more information on the LEDs available on your system, see
 	  Documentation/leds/leds-class.txt
 
+config NETFILTER_XT_TARGET_LOG
+	tristate "LOG target support"
+	default m if NETFILTER_ADVANCED=n
+	help
+	  This option adds a `LOG' target, which allows you to create rules in
+	  any iptables table which records the packet header to the syslog.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_TARGET_MARK
 	tristate '"MARK" target support'
 	depends on NETFILTER_ADVANCED

net/netfilter/Makefile

@@ -58,6 +58,7 @@ 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-$(CONFIG_NETFILTER_XT_TARGET_LOG) += xt_LOG.o
 obj-$(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