net/ipv6/netfilter/ip6t_LOG.c - linux/kernel/git/mellanox/linux - Git at Google

 /*
  * 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.
  */

 #include <linux/module.h>
 #include <linux/moduleparam.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>

 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
 MODULE_DESCRIPTION("IP6 tables LOG target module");
 MODULE_LICENSE("GPL");

 struct in_device;
 #include <net/route.h>
 #include <linux/netfilter_ipv6/ip6t_LOG.h>

 /* Use lock to serialize, so printks don't overlap */
 static DEFINE_SPINLOCK(log_lock);

 /* One level of recursion won't kill us */
 static void dump_packet(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) {
 		printk("TRUNCATED");
 		return;
 	}

 	/* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
 	printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));

 	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
 	printk("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) {
 			printk("TRUNCATED");
 			return;
 		}

 		/* Max length: 48 "OPT (...) " */
 		if (logflags & IP6T_LOG_IPOPT)
 			printk("OPT ( ");

 		switch (currenthdr) {
 		case IPPROTO_FRAGMENT: {
 			struct frag_hdr _fhdr;
 			const struct frag_hdr *fh;

 			printk("FRAG:");
 			fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
 						&_fhdr);
 			if (fh == NULL) {
 				printk("TRUNCATED ");
 				return;
 			}

 			/* Max length: 6 "65535 " */
 			printk("%u ", ntohs(fh->frag_off) & 0xFFF8);

 			/* Max length: 11 "INCOMPLETE " */
 			if (fh->frag_off & htons(0x0001))
 				printk("INCOMPLETE ");

 			printk("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)
 					printk(")");
 				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 " */
 				printk("AH ");

 				if (fragment) {
 					printk(")");
 					return;
 				}

 				ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 							&_ahdr);
 				if (ah == NULL) {
 					/*
 					 * Max length: 26 "INCOMPLETE [65535
 					 *  bytes] )"
 					 */
 					printk("INCOMPLETE [%u bytes] )",
 					       skb->len - ptr);
 					return;
 				}

 				/* Length: 15 "SPI=0xF1234567 */
 				printk("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 " */
 				printk("ESP ");

 				if (fragment) {
 					printk(")");
 					return;
 				}

 				/*
 				 * Max length: 26 "INCOMPLETE [65535 bytes] )"
 				 */
 				eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 							&_esph);
 				if (eh == NULL) {
 					printk("INCOMPLETE [%u bytes] )",
 					       skb->len - ptr);
 					return;
 				}

 				/* Length: 16 "SPI=0xF1234567 )" */
 				printk("SPI=0x%x )", ntohl(eh->spi) );

 			}
 			return;
 		default:
 			/* Max length: 20 "Unknown Ext Hdr 255" */
 			printk("Unknown Ext Hdr %u", currenthdr);
 			return;
 		}
 		if (logflags & IP6T_LOG_IPOPT)
 			printk(") ");

 		currenthdr = hp->nexthdr;
 		ptr += hdrlen;
 	}

 	switch (currenthdr) {
 	case IPPROTO_TCP: {
 		struct tcphdr _tcph;
 		const struct tcphdr *th;

 		/* Max length: 10 "PROTO=TCP " */
 		printk("PROTO=TCP ");

 		if (fragment)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
 		if (th == NULL) {
 			printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 			return;
 		}

 		/* Max length: 20 "SPT=65535 DPT=65535 " */
 		printk("SPT=%u DPT=%u ",
 		       ntohs(th->source), ntohs(th->dest));
 		/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 		if (logflags & IP6T_LOG_TCPSEQ)
 			printk("SEQ=%u ACK=%u ",
 			       ntohl(th->seq), ntohl(th->ack_seq));
 		/* Max length: 13 "WINDOW=65535 " */
 		printk("WINDOW=%u ", ntohs(th->window));
 		/* Max length: 9 "RES=0x3C " */
 		printk("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)
 			printk("CWR ");
 		if (th->ece)
 			printk("ECE ");
 		if (th->urg)
 			printk("URG ");
 		if (th->ack)
 			printk("ACK ");
 		if (th->psh)
 			printk("PSH ");
 		if (th->rst)
 			printk("RST ");
 		if (th->syn)
 			printk("SYN ");
 		if (th->fin)
 			printk("FIN ");
 		/* Max length: 11 "URGP=65535 " */
 		printk("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) {
 				printk("OPT (TRUNCATED)");
 				return;
 			}

 			/* Max length: 127 "OPT (" 15*4*2chars ") " */
 			printk("OPT (");
 			for (i =0; i < optsize; i++)
 				printk("%02X", op[i]);
 			printk(") ");
 		}
 		break;
 	}
 	case IPPROTO_UDP:
 	case IPPROTO_UDPLITE: {
 		struct udphdr _udph;
 		const struct udphdr *uh;

 		if (currenthdr == IPPROTO_UDP)
 			/* Max length: 10 "PROTO=UDP "     */
 			printk("PROTO=UDP " );
 		else	/* Max length: 14 "PROTO=UDPLITE " */
 			printk("PROTO=UDPLITE ");

 		if (fragment)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
 		if (uh == NULL) {
 			printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 			return;
 		}

 		/* Max length: 20 "SPT=65535 DPT=65535 " */
 		printk("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 " */
 		printk("PROTO=ICMPv6 ");

 		if (fragment)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 		if (ic == NULL) {
 			printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 			return;
 		}

 		/* Max length: 18 "TYPE=255 CODE=255 " */
 		printk("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 " */
 			printk("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 " */
 			printk("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) {
 				printk("[");
 				dump_packet(info, skb, ptr + sizeof(_icmp6h),
 					    0);
 				printk("] ");
 			}

 			/* Max length: 10 "MTU=65535 " */
 			if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 				printk("MTU=%u ", ntohl(ic->icmp6_mtu));
 		}
 		break;
 	}
 	/* Max length: 10 "PROTO=255 " */
 	default:
 		printk("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)
 			printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
 		read_unlock_bh(&skb->sk->sk_callback_lock);
 	}
 }

 static struct nf_loginfo default_loginfo = {
 	.type	= NF_LOG_TYPE_LOG,
 	.u = {
 		.log = {
 			.level	  = 0,
 			.logflags = NF_LOG_MASK,
 		},
 	},
 };

 static void
 ip6t_log_packet(unsigned int 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)
 {
 	if (!loginfo)
 		loginfo = &default_loginfo;

 	spin_lock_bh(&log_lock);
 	printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
 		prefix,
 		in ? in->name : "",
 		out ? out->name : "");
 	if (in && !out) {
 		unsigned int len;
 		/* MAC logging for input chain only. */
 		printk("MAC=");
 		if (skb->dev && (len = skb->dev->hard_header_len) &&
 		    skb->mac_header != skb->network_header) {
 			const unsigned char *p = skb_mac_header(skb);
 			int i;

 			if (skb->dev->type == ARPHRD_SIT &&
 			    (p -= ETH_HLEN) < skb->head)
 				p = NULL;

 			if (p != NULL) {
 				for (i = 0; i < len; i++)
 					printk("%02x%s", p[i],
 					       i == len - 1 ? "" : ":");
 			}
 			printk(" ");

 			if (skb->dev->type == ARPHRD_SIT) {
 				const struct iphdr *iph =
 					(struct iphdr *)skb_mac_header(skb);
 				printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
 				       NIPQUAD(iph->saddr),
 				       NIPQUAD(iph->daddr));
 			}
 		} else
 			printk(" ");
 	}

 	dump_packet(loginfo, skb, skb_network_offset(skb), 1);
 	printk("\n");
 	spin_unlock_bh(&log_lock);
 }

 static unsigned int
 ip6t_log_target(struct sk_buff **pskb,
 		const struct net_device *in,
 		const struct net_device *out,
 		unsigned int hooknum,
 		const struct xt_target *target,
 		const void *targinfo)
 {
 	const struct ip6t_log_info *loginfo = 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(PF_INET6, hooknum, *pskb, in, out, &li,
 			loginfo->prefix);
 	return XT_CONTINUE;
 }


 static bool ip6t_log_checkentry(const char *tablename,
 				const void *entry,
 				const struct xt_target *target,
 				void *targinfo,
 				unsigned int hook_mask)
 {
 	const struct ip6t_log_info *loginfo = targinfo;

 	if (loginfo->level >= 8) {
 		pr_debug("LOG: level %u >= 8\n", loginfo->level);
 		return false;
 	}
 	if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 		pr_debug("LOG: prefix term %i\n",
 			 loginfo->prefix[sizeof(loginfo->prefix)-1]);
 		return false;
 	}
 	return true;
 }

 static struct xt_target ip6t_log_reg __read_mostly = {
 	.name 		= "LOG",
 	.family		= AF_INET6,
 	.target 	= ip6t_log_target,
 	.targetsize	= sizeof(struct ip6t_log_info),
 	.checkentry	= ip6t_log_checkentry,
 	.me 		= THIS_MODULE,
 };

 static struct nf_logger ip6t_logger = {
 	.name		= "ip6t_LOG",
 	.logfn		= &ip6t_log_packet,
 	.me		= THIS_MODULE,
 };

 static int __init ip6t_log_init(void)
 {
 	int ret;

 	ret = xt_register_target(&ip6t_log_reg);
 	if (ret < 0)
 		return ret;
 	nf_log_register(PF_INET6, &ip6t_logger);
 	return 0;
 }

 static void __exit ip6t_log_fini(void)
 {
 	nf_log_unregister(&ip6t_logger);
 	xt_unregister_target(&ip6t_log_reg);
 }

 module_init(ip6t_log_init);
 module_exit(ip6t_log_fini);
	/*
	* 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.
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.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>

	MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
	MODULE_DESCRIPTION("IP6 tables LOG target module");
	MODULE_LICENSE("GPL");

	struct in_device;
	#include <net/route.h>
	#include <linux/netfilter_ipv6/ip6t_LOG.h>

	/* Use lock to serialize, so printks don't overlap */
	static DEFINE_SPINLOCK(log_lock);

	/* One level of recursion won't kill us */
	static void dump_packet(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) {
	printk("TRUNCATED");
	return;
	}

	/* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
	printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));

	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
	printk("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) {
	printk("TRUNCATED");
	return;
	}

	/* Max length: 48 "OPT (...) " */
	if (logflags & IP6T_LOG_IPOPT)
	printk("OPT ( ");

	switch (currenthdr) {
	case IPPROTO_FRAGMENT: {
	struct frag_hdr _fhdr;
	const struct frag_hdr *fh;

	printk("FRAG:");
	fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
	&_fhdr);
	if (fh == NULL) {
	printk("TRUNCATED ");
	return;
	}

	/* Max length: 6 "65535 " */
	printk("%u ", ntohs(fh->frag_off) & 0xFFF8);

	/* Max length: 11 "INCOMPLETE " */
	if (fh->frag_off & htons(0x0001))
	printk("INCOMPLETE ");

	printk("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)
	printk(")");
	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 " */
	printk("AH ");

	if (fragment) {
	printk(")");
	return;
	}

	ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
	&_ahdr);
	if (ah == NULL) {
	/*
	* Max length: 26 "INCOMPLETE [65535
	* bytes] )"
	*/
	printk("INCOMPLETE [%u bytes] )",
	skb->len - ptr);
	return;
	}

	/* Length: 15 "SPI=0xF1234567 */
	printk("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 " */
	printk("ESP ");

	if (fragment) {
	printk(")");
	return;
	}

	/*
	* Max length: 26 "INCOMPLETE [65535 bytes] )"
	*/
	eh = skb_header_pointer(skb, ptr, sizeof(_esph),
	&_esph);
	if (eh == NULL) {
	printk("INCOMPLETE [%u bytes] )",
	skb->len - ptr);
	return;
	}

	/* Length: 16 "SPI=0xF1234567 )" */
	printk("SPI=0x%x )", ntohl(eh->spi) );

	}
	return;
	default:
	/* Max length: 20 "Unknown Ext Hdr 255" */
	printk("Unknown Ext Hdr %u", currenthdr);
	return;
	}
	if (logflags & IP6T_LOG_IPOPT)
	printk(") ");

	currenthdr = hp->nexthdr;
	ptr += hdrlen;
	}

	switch (currenthdr) {
	case IPPROTO_TCP: {
	struct tcphdr _tcph;
	const struct tcphdr *th;

	/* Max length: 10 "PROTO=TCP " */
	printk("PROTO=TCP ");

	if (fragment)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
	if (th == NULL) {
	printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
	return;
	}

	/* Max length: 20 "SPT=65535 DPT=65535 " */
	printk("SPT=%u DPT=%u ",
	ntohs(th->source), ntohs(th->dest));
	/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
	if (logflags & IP6T_LOG_TCPSEQ)
	printk("SEQ=%u ACK=%u ",
	ntohl(th->seq), ntohl(th->ack_seq));
	/* Max length: 13 "WINDOW=65535 " */
	printk("WINDOW=%u ", ntohs(th->window));
	/* Max length: 9 "RES=0x3C " */
	printk("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)
	printk("CWR ");
	if (th->ece)
	printk("ECE ");
	if (th->urg)
	printk("URG ");
	if (th->ack)
	printk("ACK ");
	if (th->psh)
	printk("PSH ");
	if (th->rst)
	printk("RST ");
	if (th->syn)
	printk("SYN ");
	if (th->fin)
	printk("FIN ");
	/* Max length: 11 "URGP=65535 " */
	printk("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) {
	printk("OPT (TRUNCATED)");
	return;
	}

	/* Max length: 127 "OPT (" 1542chars ") " */
	printk("OPT (");
	for (i =0; i < optsize; i++)
	printk("%02X", op[i]);
	printk(") ");
	}
	break;
	}
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE: {
	struct udphdr _udph;
	const struct udphdr *uh;

	if (currenthdr == IPPROTO_UDP)
	/* Max length: 10 "PROTO=UDP " */
	printk("PROTO=UDP " );
	else /* Max length: 14 "PROTO=UDPLITE " */
	printk("PROTO=UDPLITE ");

	if (fragment)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
	if (uh == NULL) {
	printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
	return;
	}

	/* Max length: 20 "SPT=65535 DPT=65535 " */
	printk("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 " */
	printk("PROTO=ICMPv6 ");

	if (fragment)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
	if (ic == NULL) {
	printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
	return;
	}

	/* Max length: 18 "TYPE=255 CODE=255 " */
	printk("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 " */
	printk("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 " */
	printk("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) {
	printk("[");
	dump_packet(info, skb, ptr + sizeof(_icmp6h),
	0);
	printk("] ");
	}

	/* Max length: 10 "MTU=65535 " */
	if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
	printk("MTU=%u ", ntohl(ic->icmp6_mtu));
	}
	break;
	}
	/* Max length: 10 "PROTO=255 " */
	default:
	printk("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)
	printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
	read_unlock_bh(&skb->sk->sk_callback_lock);
	}
	}

	static struct nf_loginfo default_loginfo = {
	.type = NF_LOG_TYPE_LOG,
	.u = {
	.log = {
	.level = 0,
	.logflags = NF_LOG_MASK,
	},
	},
	};

	static void
	ip6t_log_packet(unsigned int 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)
	{
	if (!loginfo)
	loginfo = &default_loginfo;

	spin_lock_bh(&log_lock);
	printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
	prefix,
	in ? in->name : "",
	out ? out->name : "");
	if (in && !out) {
	unsigned int len;
	/* MAC logging for input chain only. */
	printk("MAC=");
	if (skb->dev && (len = skb->dev->hard_header_len) &&
	skb->mac_header != skb->network_header) {
	const unsigned char *p = skb_mac_header(skb);
	int i;

	if (skb->dev->type == ARPHRD_SIT &&
	(p -= ETH_HLEN) < skb->head)
	p = NULL;

	if (p != NULL) {
	for (i = 0; i < len; i++)
	printk("%02x%s", p[i],
	i == len - 1 ? "" : ":");
	}
	printk(" ");

	if (skb->dev->type == ARPHRD_SIT) {
	const struct iphdr *iph =
	(struct iphdr *)skb_mac_header(skb);
	printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
	NIPQUAD(iph->saddr),
	NIPQUAD(iph->daddr));
	}
	} else
	printk(" ");
	}

	dump_packet(loginfo, skb, skb_network_offset(skb), 1);
	printk("\n");
	spin_unlock_bh(&log_lock);
	}

	static unsigned int
	ip6t_log_target(struct sk_buff **pskb,
	const struct net_device *in,
	const struct net_device *out,
	unsigned int hooknum,
	const struct xt_target *target,
	const void *targinfo)
	{
	const struct ip6t_log_info *loginfo = 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(PF_INET6, hooknum, *pskb, in, out, &li,
	loginfo->prefix);
	return XT_CONTINUE;
	}


	static bool ip6t_log_checkentry(const char *tablename,
	const void *entry,
	const struct xt_target *target,
	void *targinfo,
	unsigned int hook_mask)
	{
	const struct ip6t_log_info *loginfo = targinfo;

	if (loginfo->level >= 8) {
	pr_debug("LOG: level %u >= 8\n", loginfo->level);
	return false;
	}
	if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
	pr_debug("LOG: prefix term %i\n",
	loginfo->prefix[sizeof(loginfo->prefix)-1]);
	return false;
	}
	return true;
	}

	static struct xt_target ip6t_log_reg __read_mostly = {
	.name = "LOG",
	.family = AF_INET6,
	.target = ip6t_log_target,
	.targetsize = sizeof(struct ip6t_log_info),
	.checkentry = ip6t_log_checkentry,
	.me = THIS_MODULE,
	};

	static struct nf_logger ip6t_logger = {
	.name = "ip6t_LOG",
	.logfn = &ip6t_log_packet,
	.me = THIS_MODULE,
	};

	static int __init ip6t_log_init(void)
	{
	int ret;

	ret = xt_register_target(&ip6t_log_reg);
	if (ret < 0)
	return ret;
	nf_log_register(PF_INET6, &ip6t_logger);
	return 0;
	}

	static void __exit ip6t_log_fini(void)
	{
	nf_log_unregister(&ip6t_logger);
	xt_unregister_target(&ip6t_log_reg);
	}

	module_init(ip6t_log_init);
	module_exit(ip6t_log_fini);