net/ipv4/netfilter/ipt_LOG.c - linux/kernel/git/bpf/bpf-next - Git at Google

 /*
  * This is a module which is used for logging packets.
  */

 /* (C) 1999-2001 Paul `Rusty' Russell
  * (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/spinlock.h>
 #include <linux/skbuff.h>
 #include <linux/ip.h>
 #include <net/icmp.h>
 #include <net/udp.h>
 #include <net/tcp.h>
 #include <net/route.h>

 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv4/ipt_LOG.h>

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 MODULE_DESCRIPTION("iptables syslog logging module");

 #if 0
 #define DEBUGP printk
 #else
 #define DEBUGP(format, args...)
 #endif

 /* 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 iphoff)
 {
 	struct iphdr _iph, *ih;
 	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, iphoff, sizeof(_iph), &_iph);
 	if (ih == NULL) {
 		printk("TRUNCATED");
 		return;
 	}

 	/* Important fields:
 	 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
 	/* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
 	printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
 	       NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));

 	/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
 	printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
 	       ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
 	       ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));

 	/* Max length: 6 "CE DF MF " */
 	if (ntohs(ih->frag_off) & IP_CE)
 		printk("CE ");
 	if (ntohs(ih->frag_off) & IP_DF)
 		printk("DF ");
 	if (ntohs(ih->frag_off) & IP_MF)
 		printk("MF ");

 	/* Max length: 11 "FRAG:65535 " */
 	if (ntohs(ih->frag_off) & IP_OFFSET)
 		printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);

 	if ((logflags & IPT_LOG_IPOPT)
 	    && ih->ihl * 4 > sizeof(struct iphdr)) {
 		unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
 		unsigned int i, optsize;

 		optsize = ih->ihl * 4 - sizeof(struct iphdr);
 		op = skb_header_pointer(skb, iphoff+sizeof(_iph),
 					optsize, _opt);
 		if (op == NULL) {
 			printk("TRUNCATED");
 			return;
 		}

 		/* Max length: 127 "OPT (" 15*4*2chars ") " */
 		printk("OPT (");
 		for (i = 0; i < optsize; i++)
 			printk("%02X", op[i]);
 		printk(") ");
 	}

 	switch (ih->protocol) {
 	case IPPROTO_TCP: {
 		struct tcphdr _tcph, *th;

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

 		if (ntohs(ih->frag_off) & IP_OFFSET)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 					sizeof(_tcph), &_tcph);
 		if (th == NULL) {
 			printk("INCOMPLETE [%u bytes] ",
 			       skb->len - iphoff - ih->ihl*4);
 			break;
 		}

 		/* 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 & IPT_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=0x3F " */
 		printk("RES=0x%02x ", (u8)(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 & IPT_LOG_TCPOPT)
 		    && th->doff * 4 > sizeof(struct tcphdr)) {
 			unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
 			unsigned char *op;
 			unsigned int i, optsize;

 			optsize = th->doff * 4 - sizeof(struct tcphdr);
 			op = skb_header_pointer(skb,
 						iphoff+ih->ihl*4+sizeof(_tcph),
 						optsize, _opt);
 			if (op == NULL) {
 				printk("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: {
 		struct udphdr _udph, *uh;

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

 		if (ntohs(ih->frag_off) & IP_OFFSET)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
 					sizeof(_udph), &_udph);
 		if (uh == NULL) {
 			printk("INCOMPLETE [%u bytes] ",
 			       skb->len - iphoff - ih->ihl*4);
 			break;
 		}

 		/* 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_ICMP: {
 		struct icmphdr _icmph, *ich;
 		static const size_t required_len[NR_ICMP_TYPES+1]
 			= { [ICMP_ECHOREPLY] = 4,
 			    [ICMP_DEST_UNREACH]
 			    = 8 + sizeof(struct iphdr),
 			    [ICMP_SOURCE_QUENCH]
 			    = 8 + sizeof(struct iphdr),
 			    [ICMP_REDIRECT]
 			    = 8 + sizeof(struct iphdr),
 			    [ICMP_ECHO] = 4,
 			    [ICMP_TIME_EXCEEDED]
 			    = 8 + sizeof(struct iphdr),
 			    [ICMP_PARAMETERPROB]
 			    = 8 + sizeof(struct iphdr),
 			    [ICMP_TIMESTAMP] = 20,
 			    [ICMP_TIMESTAMPREPLY] = 20,
 			    [ICMP_ADDRESS] = 12,
 			    [ICMP_ADDRESSREPLY] = 12 };

 		/* Max length: 11 "PROTO=ICMP " */
 		printk("PROTO=ICMP ");

 		if (ntohs(ih->frag_off) & IP_OFFSET)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 					 sizeof(_icmph), &_icmph);
 		if (ich == NULL) {
 			printk("INCOMPLETE [%u bytes] ",
 			       skb->len - iphoff - ih->ihl*4);
 			break;
 		}

 		/* Max length: 18 "TYPE=255 CODE=255 " */
 		printk("TYPE=%u CODE=%u ", ich->type, ich->code);

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		if (ich->type <= NR_ICMP_TYPES
 		    && required_len[ich->type]
 		    && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
 			printk("INCOMPLETE [%u bytes] ",
 			       skb->len - iphoff - ih->ihl*4);
 			break;
 		}

 		switch (ich->type) {
 		case ICMP_ECHOREPLY:
 		case ICMP_ECHO:
 			/* Max length: 19 "ID=65535 SEQ=65535 " */
 			printk("ID=%u SEQ=%u ",
 			       ntohs(ich->un.echo.id),
 			       ntohs(ich->un.echo.sequence));
 			break;

 		case ICMP_PARAMETERPROB:
 			/* Max length: 14 "PARAMETER=255 " */
 			printk("PARAMETER=%u ",
 			       ntohl(ich->un.gateway) >> 24);
 			break;
 		case ICMP_REDIRECT:
 			/* Max length: 24 "GATEWAY=255.255.255.255 " */
 			printk("GATEWAY=%u.%u.%u.%u ",
 			       NIPQUAD(ich->un.gateway));
 			/* Fall through */
 		case ICMP_DEST_UNREACH:
 		case ICMP_SOURCE_QUENCH:
 		case ICMP_TIME_EXCEEDED:
 			/* Max length: 3+maxlen */
 			if (!iphoff) { /* Only recurse once. */
 				printk("[");
 				dump_packet(info, skb,
 					    iphoff + ih->ihl*4+sizeof(_icmph));
 				printk("] ");
 			}

 			/* Max length: 10 "MTU=65535 " */
 			if (ich->type == ICMP_DEST_UNREACH
 			    && ich->code == ICMP_FRAG_NEEDED)
 				printk("MTU=%u ", ntohs(ich->un.frag.mtu));
 		}
 		break;
 	}
 	/* Max Length */
 	case IPPROTO_AH: {
 		struct ip_auth_hdr _ahdr, *ah;

 		if (ntohs(ih->frag_off) & IP_OFFSET)
 			break;

 		/* Max length: 9 "PROTO=AH " */
 		printk("PROTO=AH ");

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
 					sizeof(_ahdr), &_ahdr);
 		if (ah == NULL) {
 			printk("INCOMPLETE [%u bytes] ",
 			       skb->len - iphoff - ih->ihl*4);
 			break;
 		}

 		/* Length: 15 "SPI=0xF1234567 " */
 		printk("SPI=0x%x ", ntohl(ah->spi));
 		break;
 	}
 	case IPPROTO_ESP: {
 		struct ip_esp_hdr _esph, *eh;

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

 		if (ntohs(ih->frag_off) & IP_OFFSET)
 			break;

 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
 		eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
 					sizeof(_esph), &_esph);
 		if (eh == NULL) {
 			printk("INCOMPLETE [%u bytes] ",
 			       skb->len - iphoff - ih->ihl*4);
 			break;
 		}

 		/* Length: 15 "SPI=0xF1234567 " */
 		printk("SPI=0x%x ", ntohl(eh->spi));
 		break;
 	}
 	/* Max length: 10 "PROTO 255 " */
 	default:
 		printk("PROTO=%u ", ih->protocol);
 	}

 	/* Max length: 15 "UID=4294967295 " */
  	if ((logflags & IPT_LOG_UID) && !iphoff && 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);
 	}

 	/* Proto    Max log string length */
 	/* IP:      40+46+6+11+127 = 230 */
 	/* TCP:     10+max(25,20+30+13+9+32+11+127) = 252 */
 	/* UDP:     10+max(25,20) = 35 */
 	/* ICMP:    11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
 	/* ESP:     10+max(25)+15 = 50 */
 	/* AH:      9+max(25)+15 = 49 */
 	/* unknown: 10 */

 	/* (ICMP allows recursion one level deep) */
 	/* maxlen =  IP + ICMP +  IP + max(TCP,UDP,ICMP,unknown) */
 	/* maxlen = 230+   91  + 230 + 252 = 803 */
 }

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

 static void
 ipt_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 : "");
 #ifdef CONFIG_BRIDGE_NETFILTER
 	if (skb->nf_bridge) {
 		struct net_device *physindev = skb->nf_bridge->physindev;
 		struct net_device *physoutdev = skb->nf_bridge->physoutdev;

 		if (physindev && in != physindev)
 			printk("PHYSIN=%s ", physindev->name);
 		if (physoutdev && out != physoutdev)
 			printk("PHYSOUT=%s ", physoutdev->name);
 	}
 #endif

 	if (in && !out) {
 		/* MAC logging for input chain only. */
 		printk("MAC=");
 		if (skb->dev && skb->dev->hard_header_len
 		    && skb->mac.raw != (void*)skb->nh.iph) {
 			int i;
 			unsigned char *p = skb->mac.raw;
 			for (i = 0; i < skb->dev->hard_header_len; i++,p++)
 				printk("%02x%c", *p,
 				       i==skb->dev->hard_header_len - 1
 				       ? ' ':':');
 		} else
 			printk(" ");
 	}

 	dump_packet(loginfo, skb, 0);
 	printk("\n");
 	spin_unlock_bh(&log_lock);
 }

 static unsigned int
 ipt_log_target(struct sk_buff **pskb,
 	       const struct net_device *in,
 	       const struct net_device *out,
 	       unsigned int hooknum,
 	       const void *targinfo,
 	       void *userinfo)
 {
 	const struct ipt_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;

 	nf_log_packet(PF_INET, hooknum, *pskb, in, out, &li, loginfo->prefix);

 	return IPT_CONTINUE;
 }

 static int ipt_log_checkentry(const char *tablename,
 			      const void *e,
 			      void *targinfo,
 			      unsigned int targinfosize,
 			      unsigned int hook_mask)
 {
 	const struct ipt_log_info *loginfo = targinfo;

 	if (targinfosize != IPT_ALIGN(sizeof(struct ipt_log_info))) {
 		DEBUGP("LOG: targinfosize %u != %u\n",
 		       targinfosize, IPT_ALIGN(sizeof(struct ipt_log_info)));
 		return 0;
 	}

 	if (loginfo->level >= 8) {
 		DEBUGP("LOG: level %u >= 8\n", loginfo->level);
 		return 0;
 	}

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

 	return 1;
 }

 static struct ipt_target ipt_log_reg = {
 	.name		= "LOG",
 	.target		= ipt_log_target,
 	.checkentry	= ipt_log_checkentry,
 	.me		= THIS_MODULE,
 };

 static struct nf_logger ipt_log_logger ={
 	.name		= "ipt_LOG",
 	.logfn		= &ipt_log_packet,
 	.me		= THIS_MODULE,
 };

 static int __init init(void)
 {
 	if (ipt_register_target(&ipt_log_reg))
 		return -EINVAL;
 	if (nf_log_register(PF_INET, &ipt_log_logger) < 0) {
 		printk(KERN_WARNING "ipt_LOG: not logging via system console "
 		       "since somebody else already registered for PF_INET\n");
 		/* we cannot make module load fail here, since otherwise
 		 * iptables userspace would abort */
 	}

 	return 0;
 }

 static void __exit fini(void)
 {
 	nf_log_unregister_logger(&ipt_log_logger);
 	ipt_unregister_target(&ipt_log_reg);
 }

 module_init(init);
 module_exit(fini);
	/*
	* This is a module which is used for logging packets.
	*/

	/* (C) 1999-2001 Paul `Rusty' Russell
	* (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/spinlock.h>
	#include <linux/skbuff.h>
	#include <linux/ip.h>
	#include <net/icmp.h>
	#include <net/udp.h>
	#include <net/tcp.h>
	#include <net/route.h>

	#include <linux/netfilter.h>
	#include <linux/netfilter_ipv4/ip_tables.h>
	#include <linux/netfilter_ipv4/ipt_LOG.h>

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	MODULE_DESCRIPTION("iptables syslog logging module");

	#if 0
	#define DEBUGP printk
	#else
	#define DEBUGP(format, args...)
	#endif

	/* 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 iphoff)
	{
	struct iphdr _iph, *ih;
	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, iphoff, sizeof(_iph), &_iph);
	if (ih == NULL) {
	printk("TRUNCATED");
	return;
	}

	/* Important fields:
	* TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
	/* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
	printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
	NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));

	/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
	printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
	ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
	ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));

	/* Max length: 6 "CE DF MF " */
	if (ntohs(ih->frag_off) & IP_CE)
	printk("CE ");
	if (ntohs(ih->frag_off) & IP_DF)
	printk("DF ");
	if (ntohs(ih->frag_off) & IP_MF)
	printk("MF ");

	/* Max length: 11 "FRAG:65535 " */
	if (ntohs(ih->frag_off) & IP_OFFSET)
	printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);

	if ((logflags & IPT_LOG_IPOPT)
	&& ih->ihl * 4 > sizeof(struct iphdr)) {
	unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
	unsigned int i, optsize;

	optsize = ih->ihl * 4 - sizeof(struct iphdr);
	op = skb_header_pointer(skb, iphoff+sizeof(_iph),
	optsize, _opt);
	if (op == NULL) {
	printk("TRUNCATED");
	return;
	}

	/* Max length: 127 "OPT (" 1542chars ") " */
	printk("OPT (");
	for (i = 0; i < optsize; i++)
	printk("%02X", op[i]);
	printk(") ");
	}

	switch (ih->protocol) {
	case IPPROTO_TCP: {
	struct tcphdr _tcph, *th;

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

	if (ntohs(ih->frag_off) & IP_OFFSET)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
	sizeof(_tcph), &_tcph);
	if (th == NULL) {
	printk("INCOMPLETE [%u bytes] ",
	skb->len - iphoff - ih->ihl*4);
	break;
	}

	/* 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 & IPT_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=0x3F " */
	printk("RES=0x%02x ", (u8)(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 & IPT_LOG_TCPOPT)
	&& th->doff * 4 > sizeof(struct tcphdr)) {
	unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
	unsigned char *op;
	unsigned int i, optsize;

	optsize = th->doff * 4 - sizeof(struct tcphdr);
	op = skb_header_pointer(skb,
	iphoff+ih->ihl*4+sizeof(_tcph),
	optsize, _opt);
	if (op == NULL) {
	printk("TRUNCATED");
	return;
	}

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

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

	if (ntohs(ih->frag_off) & IP_OFFSET)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
	sizeof(_udph), &_udph);
	if (uh == NULL) {
	printk("INCOMPLETE [%u bytes] ",
	skb->len - iphoff - ih->ihl*4);
	break;
	}

	/* 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_ICMP: {
	struct icmphdr _icmph, *ich;
	static const size_t required_len[NR_ICMP_TYPES+1]
	= { [ICMP_ECHOREPLY] = 4,
	[ICMP_DEST_UNREACH]
	= 8 + sizeof(struct iphdr),
	[ICMP_SOURCE_QUENCH]
	= 8 + sizeof(struct iphdr),
	[ICMP_REDIRECT]
	= 8 + sizeof(struct iphdr),
	[ICMP_ECHO] = 4,
	[ICMP_TIME_EXCEEDED]
	= 8 + sizeof(struct iphdr),
	[ICMP_PARAMETERPROB]
	= 8 + sizeof(struct iphdr),
	[ICMP_TIMESTAMP] = 20,
	[ICMP_TIMESTAMPREPLY] = 20,
	[ICMP_ADDRESS] = 12,
	[ICMP_ADDRESSREPLY] = 12 };

	/* Max length: 11 "PROTO=ICMP " */
	printk("PROTO=ICMP ");

	if (ntohs(ih->frag_off) & IP_OFFSET)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
	sizeof(_icmph), &_icmph);
	if (ich == NULL) {
	printk("INCOMPLETE [%u bytes] ",
	skb->len - iphoff - ih->ihl*4);
	break;
	}

	/* Max length: 18 "TYPE=255 CODE=255 " */
	printk("TYPE=%u CODE=%u ", ich->type, ich->code);

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	if (ich->type <= NR_ICMP_TYPES
	&& required_len[ich->type]
	&& skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
	printk("INCOMPLETE [%u bytes] ",
	skb->len - iphoff - ih->ihl*4);
	break;
	}

	switch (ich->type) {
	case ICMP_ECHOREPLY:
	case ICMP_ECHO:
	/* Max length: 19 "ID=65535 SEQ=65535 " */
	printk("ID=%u SEQ=%u ",
	ntohs(ich->un.echo.id),
	ntohs(ich->un.echo.sequence));
	break;

	case ICMP_PARAMETERPROB:
	/* Max length: 14 "PARAMETER=255 " */
	printk("PARAMETER=%u ",
	ntohl(ich->un.gateway) >> 24);
	break;
	case ICMP_REDIRECT:
	/* Max length: 24 "GATEWAY=255.255.255.255 " */
	printk("GATEWAY=%u.%u.%u.%u ",
	NIPQUAD(ich->un.gateway));
	/* Fall through */
	case ICMP_DEST_UNREACH:
	case ICMP_SOURCE_QUENCH:
	case ICMP_TIME_EXCEEDED:
	/* Max length: 3+maxlen */
	if (!iphoff) { /* Only recurse once. */
	printk("[");
	dump_packet(info, skb,
	iphoff + ih->ihl*4+sizeof(_icmph));
	printk("] ");
	}

	/* Max length: 10 "MTU=65535 " */
	if (ich->type == ICMP_DEST_UNREACH
	&& ich->code == ICMP_FRAG_NEEDED)
	printk("MTU=%u ", ntohs(ich->un.frag.mtu));
	}
	break;
	}
	/* Max Length */
	case IPPROTO_AH: {
	struct ip_auth_hdr _ahdr, *ah;

	if (ntohs(ih->frag_off) & IP_OFFSET)
	break;

	/* Max length: 9 "PROTO=AH " */
	printk("PROTO=AH ");

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
	sizeof(_ahdr), &_ahdr);
	if (ah == NULL) {
	printk("INCOMPLETE [%u bytes] ",
	skb->len - iphoff - ih->ihl*4);
	break;
	}

	/* Length: 15 "SPI=0xF1234567 " */
	printk("SPI=0x%x ", ntohl(ah->spi));
	break;
	}
	case IPPROTO_ESP: {
	struct ip_esp_hdr _esph, *eh;

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

	if (ntohs(ih->frag_off) & IP_OFFSET)
	break;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
	sizeof(_esph), &_esph);
	if (eh == NULL) {
	printk("INCOMPLETE [%u bytes] ",
	skb->len - iphoff - ih->ihl*4);
	break;
	}

	/* Length: 15 "SPI=0xF1234567 " */
	printk("SPI=0x%x ", ntohl(eh->spi));
	break;
	}
	/* Max length: 10 "PROTO 255 " */
	default:
	printk("PROTO=%u ", ih->protocol);
	}

	/* Max length: 15 "UID=4294967295 " */
	if ((logflags & IPT_LOG_UID) && !iphoff && 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);
	}

	/* Proto Max log string length */
	/* IP: 40+46+6+11+127 = 230 */
	/* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */
	/* UDP: 10+max(25,20) = 35 */
	/* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
	/* ESP: 10+max(25)+15 = 50 */
	/* AH: 9+max(25)+15 = 49 */
	/* unknown: 10 */

	/* (ICMP allows recursion one level deep) */
	/* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */
	/* maxlen = 230+ 91 + 230 + 252 = 803 */
	}

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

	static void
	ipt_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 : "");
	#ifdef CONFIG_BRIDGE_NETFILTER
	if (skb->nf_bridge) {
	struct net_device *physindev = skb->nf_bridge->physindev;
	struct net_device *physoutdev = skb->nf_bridge->physoutdev;

	if (physindev && in != physindev)
	printk("PHYSIN=%s ", physindev->name);
	if (physoutdev && out != physoutdev)
	printk("PHYSOUT=%s ", physoutdev->name);
	}
	#endif

	if (in && !out) {
	/* MAC logging for input chain only. */
	printk("MAC=");
	if (skb->dev && skb->dev->hard_header_len
	&& skb->mac.raw != (void*)skb->nh.iph) {
	int i;
	unsigned char *p = skb->mac.raw;
	for (i = 0; i < skb->dev->hard_header_len; i++,p++)
	printk("%02x%c", *p,
	i==skb->dev->hard_header_len - 1
	? ' ':':');
	} else
	printk(" ");
	}

	dump_packet(loginfo, skb, 0);
	printk("\n");
	spin_unlock_bh(&log_lock);
	}

	static unsigned int
	ipt_log_target(struct sk_buff **pskb,
	const struct net_device *in,
	const struct net_device *out,
	unsigned int hooknum,
	const void *targinfo,
	void *userinfo)
	{
	const struct ipt_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;

	nf_log_packet(PF_INET, hooknum, *pskb, in, out, &li, loginfo->prefix);

	return IPT_CONTINUE;
	}

	static int ipt_log_checkentry(const char *tablename,
	const void *e,
	void *targinfo,
	unsigned int targinfosize,
	unsigned int hook_mask)
	{
	const struct ipt_log_info *loginfo = targinfo;

	if (targinfosize != IPT_ALIGN(sizeof(struct ipt_log_info))) {
	DEBUGP("LOG: targinfosize %u != %u\n",
	targinfosize, IPT_ALIGN(sizeof(struct ipt_log_info)));
	return 0;
	}

	if (loginfo->level >= 8) {
	DEBUGP("LOG: level %u >= 8\n", loginfo->level);
	return 0;
	}

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

	return 1;
	}

	static struct ipt_target ipt_log_reg = {
	.name = "LOG",
	.target = ipt_log_target,
	.checkentry = ipt_log_checkentry,
	.me = THIS_MODULE,
	};

	static struct nf_logger ipt_log_logger ={
	.name = "ipt_LOG",
	.logfn = &ipt_log_packet,
	.me = THIS_MODULE,
	};

	static int __init init(void)
	{
	if (ipt_register_target(&ipt_log_reg))
	return -EINVAL;
	if (nf_log_register(PF_INET, &ipt_log_logger) < 0) {
	printk(KERN_WARNING "ipt_LOG: not logging via system console "
	"since somebody else already registered for PF_INET\n");
	/* we cannot make module load fail here, since otherwise
	* iptables userspace would abort */
	}

	return 0;
	}

	static void __exit fini(void)
	{
	nf_log_unregister_logger(&ipt_log_logger);
	ipt_unregister_target(&ipt_log_reg);
	}

	module_init(init);
	module_exit(fini);