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: Richard Weinberger <richard@nod.at>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 921 insertions, 0 deletions

diff --git a/net/netfilter/xt_LOG.c b/net/netfilter/xt_LOG.c
new file mode 100644
index 000000000000..1595608a892d
--- /dev/null
+++ b/net/netfilter/xt_LOG.c
@@ -0,0 +1,921 @@
+/*
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/ip.h>
+#include <net/ipv6.h>
+#include <net/icmp.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+#include <net/route.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_LOG.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <net/netfilter/nf_log.h>
+#include <net/netfilter/xt_log.h>
+
+static struct nf_loginfo default_loginfo = {
+	.type	= NF_LOG_TYPE_LOG,
+	.u = {
+		.log = {
+			.level    = 5,
+			.logflags = NF_LOG_MASK,
+		},
+	},
+};
+
+static int dump_udp_header(struct sbuff *m, const struct sk_buff *skb,
+			   u8 proto, int fragment, unsigned int offset)
+{
+	struct udphdr _udph;
+	const struct udphdr *uh;
+
+	if (proto == 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)
+		goto out;
+
+	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
+	uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
+	if (uh == NULL) {
+		sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
+
+		return 1;
+	}
+
+	/* 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));
+
+out:
+	return 0;
+}
+
+static int dump_tcp_header(struct sbuff *m, const struct sk_buff *skb,
+			   u8 proto, int fragment, unsigned int offset,
+			   unsigned int logflags)
+{
+	struct tcphdr _tcph;
+	const struct tcphdr *th;
+
+	/* Max length: 10 "PROTO=TCP " */
+	sb_add(m, "PROTO=TCP ");
+
+	if (fragment)
+		return 0;
+
+	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
+	th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
+	if (th == NULL) {
+		sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
+		return 1;
+	}
+
+	/* 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 & XT_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 & XT_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, offset + sizeof(struct tcphdr),
+					optsize, _opt);
+		if (op == NULL) {
+			sb_add(m, "OPT (TRUNCATED)");
+			return 1;
+		}
+
+		/* 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, ") ");
+	}
+
+	return 0;
+}
+
+/* One level of recursion won't kill us */
+static void dump_ipv4_packet(struct sbuff *m,
+			const struct nf_loginfo *info,
+			const struct sk_buff *skb,
+			unsigned int iphoff)
+{
+	struct iphdr _iph;
+	const struct iphdr *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) {
+		sb_add(m, "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 " */
+	sb_add(m, "SRC=%pI4 DST=%pI4 ",
+	       &ih->saddr, &ih->daddr);
+
+	/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
+	sb_add(m, "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)
+		sb_add(m, "CE ");
+	if (ntohs(ih->frag_off) & IP_DF)
+		sb_add(m, "DF ");
+	if (ntohs(ih->frag_off) & IP_MF)
+		sb_add(m, "MF ");
+
+	/* Max length: 11 "FRAG:65535 " */
+	if (ntohs(ih->frag_off) & IP_OFFSET)
+		sb_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
+
+	if ((logflags & XT_LOG_IPOPT) &&
+	    ih->ihl * 4 > sizeof(struct iphdr)) {
+		const unsigned char *op;
+		unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
+		unsigned int i, optsize;
+
+		optsize = ih->ihl * 4 - sizeof(struct iphdr);
+		op = skb_header_pointer(skb, iphoff+sizeof(_iph),
+					optsize, _opt);
+		if (op == NULL) {
+			sb_add(m, "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, ") ");
+	}
+
+	switch (ih->protocol) {
+	case IPPROTO_TCP:
+		if (dump_tcp_header(m, skb, ih->protocol,
+				    ntohs(ih->frag_off) & IP_OFFSET,
+				    iphoff+ih->ihl*4, logflags))
+			return;
+	case IPPROTO_UDP:
+	case IPPROTO_UDPLITE:
+		if (dump_udp_header(m, skb, ih->protocol,
+				    ntohs(ih->frag_off) & IP_OFFSET,
+				    iphoff+ih->ihl*4))
+			return;
+	case IPPROTO_ICMP: {
+		struct icmphdr _icmph;
+		const struct icmphdr *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 " */
+		sb_add(m, "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) {
+			sb_add(m, "INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - ih->ihl*4);
+			break;
+		}
+
+		/* Max length: 18 "TYPE=255 CODE=255 " */
+		sb_add(m, "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]) {
+			sb_add(m, "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 " */
+			sb_add(m, "ID=%u SEQ=%u ",
+			       ntohs(ich->un.echo.id),
+			       ntohs(ich->un.echo.sequence));
+			break;
+
+		case ICMP_PARAMETERPROB:
+			/* Max length: 14 "PARAMETER=255 " */
+			sb_add(m, "PARAMETER=%u ",
+			       ntohl(ich->un.gateway) >> 24);
+			break;
+		case ICMP_REDIRECT:
+			/* Max length: 24 "GATEWAY=255.255.255.255 " */
+			sb_add(m, "GATEWAY=%pI4 ", &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. */
+				sb_add(m, "[");
+				dump_ipv4_packet(m, info, skb,
+					    iphoff + ih->ihl*4+sizeof(_icmph));
+				sb_add(m, "] ");
+			}
+
+			/* Max length: 10 "MTU=65535 " */
+			if (ich->type == ICMP_DEST_UNREACH &&
+			    ich->code == ICMP_FRAG_NEEDED)
+				sb_add(m, "MTU=%u ", ntohs(ich->un.frag.mtu));
+		}
+		break;
+	}
+	/* Max Length */
+	case IPPROTO_AH: {
+		struct ip_auth_hdr _ahdr;
+		const struct ip_auth_hdr *ah;
+
+		if (ntohs(ih->frag_off) & IP_OFFSET)
+			break;
+
+		/* Max length: 9 "PROTO=AH " */
+		sb_add(m, "PROTO=AH ");
+
+		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
+		ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
+					sizeof(_ahdr), &_ahdr);
+		if (ah == NULL) {
+			sb_add(m, "INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - ih->ihl*4);
+			break;
+		}
+
+		/* Length: 15 "SPI=0xF1234567 " */
+		sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
+		break;
+	}
+	case IPPROTO_ESP: {
+		struct ip_esp_hdr _esph;
+		const struct ip_esp_hdr *eh;
+
+		/* Max length: 10 "PROTO=ESP " */
+		sb_add(m, "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) {
+			sb_add(m, "INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - ih->ihl*4);
+			break;
+		}
+
+		/* Length: 15 "SPI=0xF1234567 " */
+		sb_add(m, "SPI=0x%x ", ntohl(eh->spi));
+		break;
+	}
+	/* Max length: 10 "PROTO 255 " */
+	default:
+		sb_add(m, "PROTO=%u ", ih->protocol);
+	}
+
+	/* Max length: 15 "UID=4294967295 " */
+	if ((logflags & XT_LOG_UID) && !iphoff && 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 (!iphoff && skb->mark)
+		sb_add(m, "MARK=0x%x ", skb->mark);
+
+	/* 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 */
+	/* UDPLITE: 14+max(25,20) = 39 */
+	/* 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 void dump_ipv4_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 & XT_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 i;
+
+		sb_add(m, "%02x", *p++);
+		for (i = 1; i < dev->hard_header_len; i++, p++)
+			sb_add(m, ":%02x", *p);
+	}
+	sb_add(m, " ");
+}
+
+static void
+log_packet_common(struct sbuff *m,
+		  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)
+{
+	sb_add(m, "<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
+	       prefix,
+	       in ? in->name : "",
+	       out ? out->name : "");
+#ifdef CONFIG_BRIDGE_NETFILTER
+	if (skb->nf_bridge) {
+		const struct net_device *physindev;
+		const struct net_device *physoutdev;
+
+		physindev = skb->nf_bridge->physindev;
+		if (physindev && in != physindev)
+			sb_add(m, "PHYSIN=%s ", physindev->name);
+		physoutdev = skb->nf_bridge->physoutdev;
+		if (physoutdev && out != physoutdev)
+			sb_add(m, "PHYSOUT=%s ", physoutdev->name);
+	}
+#endif
+}
+
+
+static void
+ipt_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;
+
+	log_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix);
+
+	if (in != NULL)
+		dump_ipv4_mac_header(m, loginfo, skb);
+
+	dump_ipv4_packet(m, loginfo, skb, 0);
+
+	sb_close(m);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+/* One level of recursion won't kill us */
+static void dump_ipv6_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 & XT_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 & XT_LOG_IPOPT)
+					sb_add(m, ")");
+				return;
+			}
+			hdrlen = ipv6_optlen(hp);
+			break;
+		/* Max Length */
+		case IPPROTO_AH:
+			if (logflags & XT_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 & XT_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 & XT_LOG_IPOPT)
+			sb_add(m, ") ");
+
+		currenthdr = hp->nexthdr;
+		ptr += hdrlen;
+	}
+
+	switch (currenthdr) {
+	case IPPROTO_TCP:
+		if (dump_tcp_header(m, skb, currenthdr, fragment, ptr,
+		    logflags))
+			return;
+	case IPPROTO_UDP:
+	case IPPROTO_UDPLITE:
+		if (dump_udp_header(m, skb, currenthdr, fragment, ptr))
+			return;
+	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_ipv6_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 & XT_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_ipv6_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 & XT_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;
+
+			if (p < 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 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;
+
+	log_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix);
+
+	if (in != NULL)
+		dump_ipv6_mac_header(m, loginfo, skb);
+
+	dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
+
+	sb_close(m);
+}
+#endif
+
+static unsigned int
+log_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct xt_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;
+
+	if (par->family == NFPROTO_IPV4)
+		ipt_log_packet(NFPROTO_IPV4, par->hooknum, skb, par->in,
+			       par->out, &li, loginfo->prefix);
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (par->family == NFPROTO_IPV6)
+		ip6t_log_packet(NFPROTO_IPV6, par->hooknum, skb, par->in,
+				par->out, &li, loginfo->prefix);
+#endif
+	else
+		WARN_ON_ONCE(1);
+
+	return XT_CONTINUE;
+}
+
+static int log_tg_check(const struct xt_tgchk_param *par)
+{
+	const struct xt_log_info *loginfo = par->targinfo;
+
+	if (par->family != NFPROTO_IPV4 && par->family != NFPROTO_IPV6)
+		return -EINVAL;
+
+	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 is not null-terminated\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct xt_target log_tg_regs[] __read_mostly = {
+	{
+		.name		= "LOG",
+		.family		= NFPROTO_IPV4,
+		.target		= log_tg,
+		.targetsize	= sizeof(struct xt_log_info),
+		.checkentry	= log_tg_check,
+		.me		= THIS_MODULE,
+	},
+#if IS_ENABLED(CONFIG_IPV6)
+	{
+		.name		= "LOG",
+		.family		= NFPROTO_IPV6,
+		.target		= log_tg,
+		.targetsize	= sizeof(struct xt_log_info),
+		.checkentry	= log_tg_check,
+		.me		= THIS_MODULE,
+	},
+#endif
+};
+
+static struct nf_logger ipt_log_logger __read_mostly = {
+	.name		= "ipt_LOG",
+	.logfn		= &ipt_log_packet,
+	.me		= THIS_MODULE,
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+static struct nf_logger ip6t_log_logger __read_mostly = {
+	.name		= "ip6t_LOG",
+	.logfn		= &ip6t_log_packet,
+	.me		= THIS_MODULE,
+};
+#endif
+
+static int __init log_tg_init(void)
+{
+	int ret;
+
+	ret = xt_register_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
+	if (ret < 0)
+		return ret;
+
+	nf_log_register(NFPROTO_IPV4, &ipt_log_logger);
+#if IS_ENABLED(CONFIG_IPV6)
+	nf_log_register(NFPROTO_IPV6, &ip6t_log_logger);
+#endif
+	return 0;
+}
+
+static void __exit log_tg_exit(void)
+{
+	nf_log_unregister(&ipt_log_logger);
+#if IS_ENABLED(CONFIG_IPV6)
+	nf_log_unregister(&ip6t_log_logger);
+#endif
+	xt_unregister_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
+}
+
+module_init(log_tg_init);
+module_exit(log_tg_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
+MODULE_DESCRIPTION("Xtables: IPv4/IPv6 packet logging");
+MODULE_ALIAS("ipt_LOG");
+MODULE_ALIAS("ip6t_LOG");