netfilter: log: split family specific code to nf_log_{ip,ip6,common}.c files

The plain text logging is currently embedded into the xt_LOG target.
In order to be able to use the plain text logging from nft_log, as a
first step, this patch moves the family specific code to the following
files and Kconfig symbols:

1) net/ipv4/netfilter/nf_log_ip.c: CONFIG_NF_LOG_IPV4
2) net/ipv6/netfilter/nf_log_ip6.c: CONFIG_NF_LOG_IPV6
3) net/netfilter/nf_log_common.c: CONFIG_NF_LOG_COMMON

These new modules will be required by xt_LOG and nft_log. This patch
is based on original patch from Arturo Borrero Gonzalez.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 393 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 730faacbc5f8..0c980293d225 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -159,6 +159,11 @@ config IP_NF_TARGET_SYNPROXY
 
 	  To compile it as a module, choose M here. If unsure, say N.
 
+config NF_LOG_IPV4
+	tristate "IPv4 packet logging"
+	default m if NETFILTER_ADVANCED=n
+	select NF_LOG_COMMON
+
 # NAT + specific targets: nf_conntrack
 config NF_NAT_IPV4
 	tristate "IPv4 NAT"
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 90b82405331e..730e0c1ead90 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -19,6 +19,9 @@ obj-$(CONFIG_NF_NAT_IPV4) += nf_nat_ipv4.o
 # defrag
 obj-$(CONFIG_NF_DEFRAG_IPV4) += nf_defrag_ipv4.o
 
+# logging
+obj-$(CONFIG_NF_LOG_IPV4) += nf_log_ipv4.o
+
 # NAT helpers (nf_conntrack)
 obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
 obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
diff --git a/net/ipv4/netfilter/nf_log_ipv4.c b/net/ipv4/netfilter/nf_log_ipv4.c
new file mode 100644
index 000000000000..7e69a401a29e
--- /dev/null
+++ b/net/ipv4/netfilter/nf_log_ipv4.c
@@ -0,0 +1,385 @@
+/* (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/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/xt_LOG.h>
+#include <net/netfilter/nf_log.h>
+
+static struct nf_loginfo default_loginfo = {
+	.type	= NF_LOG_TYPE_LOG,
+	.u = {
+		.log = {
+			.level	  = 5,
+			.logflags = NF_LOG_MASK,
+		},
+	},
+};
+
+/* One level of recursion won't kill us */
+static void dump_ipv4_packet(struct nf_log_buf *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) {
+		nf_log_buf_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 " */
+	nf_log_buf_add(m, "SRC=%pI4 DST=%pI4 ", &ih->saddr, &ih->daddr);
+
+	/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
+	nf_log_buf_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)
+		nf_log_buf_add(m, "CE ");
+	if (ntohs(ih->frag_off) & IP_DF)
+		nf_log_buf_add(m, "DF ");
+	if (ntohs(ih->frag_off) & IP_MF)
+		nf_log_buf_add(m, "MF ");
+
+	/* Max length: 11 "FRAG:65535 " */
+	if (ntohs(ih->frag_off) & IP_OFFSET)
+		nf_log_buf_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) {
+			nf_log_buf_add(m, "TRUNCATED");
+			return;
+		}
+
+		/* Max length: 127 "OPT (" 15*4*2chars ") " */
+		nf_log_buf_add(m, "OPT (");
+		for (i = 0; i < optsize; i++)
+			nf_log_buf_add(m, "%02X", op[i]);
+		nf_log_buf_add(m, ") ");
+	}
+
+	switch (ih->protocol) {
+	case IPPROTO_TCP:
+		if (nf_log_dump_tcp_header(m, skb, ih->protocol,
+					   ntohs(ih->frag_off) & IP_OFFSET,
+					   iphoff+ih->ihl*4, logflags))
+			return;
+		break;
+	case IPPROTO_UDP:
+	case IPPROTO_UDPLITE:
+		if (nf_log_dump_udp_header(m, skb, ih->protocol,
+					   ntohs(ih->frag_off) & IP_OFFSET,
+					   iphoff+ih->ihl*4))
+			return;
+		break;
+	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 " */
+		nf_log_buf_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) {
+			nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
+				       skb->len - iphoff - ih->ihl*4);
+			break;
+		}
+
+		/* Max length: 18 "TYPE=255 CODE=255 " */
+		nf_log_buf_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]) {
+			nf_log_buf_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 " */
+			nf_log_buf_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 " */
+			nf_log_buf_add(m, "PARAMETER=%u ",
+				       ntohl(ich->un.gateway) >> 24);
+			break;
+		case ICMP_REDIRECT:
+			/* Max length: 24 "GATEWAY=255.255.255.255 " */
+			nf_log_buf_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. */
+				nf_log_buf_add(m, "[");
+				dump_ipv4_packet(m, info, skb,
+					    iphoff + ih->ihl*4+sizeof(_icmph));
+				nf_log_buf_add(m, "] ");
+			}
+
+			/* Max length: 10 "MTU=65535 " */
+			if (ich->type == ICMP_DEST_UNREACH &&
+			    ich->code == ICMP_FRAG_NEEDED) {
+				nf_log_buf_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 " */
+		nf_log_buf_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) {
+			nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
+				       skb->len - iphoff - ih->ihl*4);
+			break;
+		}
+
+		/* Length: 15 "SPI=0xF1234567 " */
+		nf_log_buf_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 " */
+		nf_log_buf_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) {
+			nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
+				       skb->len - iphoff - ih->ihl*4);
+			break;
+		}
+
+		/* Length: 15 "SPI=0xF1234567 " */
+		nf_log_buf_add(m, "SPI=0x%x ", ntohl(eh->spi));
+		break;
+	}
+	/* Max length: 10 "PROTO 255 " */
+	default:
+		nf_log_buf_add(m, "PROTO=%u ", ih->protocol);
+	}
+
+	/* Max length: 15 "UID=4294967295 " */
+	if ((logflags & XT_LOG_UID) && !iphoff)
+		nf_log_dump_sk_uid_gid(m, skb->sk);
+
+	/* Max length: 16 "MARK=0xFFFFFFFF " */
+	if (!iphoff && skb->mark)
+		nf_log_buf_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 nf_log_buf *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:
+		nf_log_buf_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:
+	nf_log_buf_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;
+
+		nf_log_buf_add(m, "%02x", *p++);
+		for (i = 1; i < dev->hard_header_len; i++, p++)
+			nf_log_buf_add(m, ":%02x", *p);
+	}
+	nf_log_buf_add(m, " ");
+}
+
+void nf_log_ip_packet(struct net *net, 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 nf_log_buf *m;
+
+	/* FIXME: Disabled from containers until syslog ns is supported */
+	if (!net_eq(net, &init_net))
+		return;
+
+	m = nf_log_buf_open();
+
+	if (!loginfo)
+		loginfo = &default_loginfo;
+
+	nf_log_dump_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);
+
+	nf_log_buf_close(m);
+}
+EXPORT_SYMBOL_GPL(nf_log_ip_packet);
+
+static struct nf_logger nf_ip_logger __read_mostly = {
+	.name		= "nf_log_ipv4",
+	.type		= NF_LOG_TYPE_LOG,
+	.logfn		= nf_log_ip_packet,
+	.me		= THIS_MODULE,
+};
+
+static int __net_init nf_log_ipv4_net_init(struct net *net)
+{
+	nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger);
+	return 0;
+}
+
+static void __net_exit nf_log_ipv4_net_exit(struct net *net)
+{
+	nf_log_unset(net, &nf_ip_logger);
+}
+
+static struct pernet_operations nf_log_ipv4_net_ops = {
+	.init = nf_log_ipv4_net_init,
+	.exit = nf_log_ipv4_net_exit,
+};
+
+static int __init nf_log_ipv4_init(void)
+{
+	int ret;
+
+	ret = register_pernet_subsys(&nf_log_ipv4_net_ops);
+	if (ret < 0)
+		return ret;
+
+	nf_log_register(NFPROTO_IPV4, &nf_ip_logger);
+	return 0;
+}
+
+static void __exit nf_log_ipv4_exit(void)
+{
+	unregister_pernet_subsys(&nf_log_ipv4_net_ops);
+	nf_log_unregister(&nf_ip_logger);
+}
+
+module_init(nf_log_ipv4_init);
+module_exit(nf_log_ipv4_exit);
+
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("Netfilter IPv4 packet logging");
+MODULE_LICENSE("GPL");