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, 425 insertions, 0 deletions

diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index 4bff1f2..1537130 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -227,6 +227,11 @@ config IP6_NF_SECURITY
 
          If unsure, say N.
 
+config NF_LOG_IPV6
+	tristate "IPv6 packet logging"
+	depends on NETFILTER_ADVANCED
+	select NF_LOG_COMMON
+
 config NF_NAT_IPV6
 	tristate "IPv6 NAT"
 	depends on NF_CONNTRACK_IPV6
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index 70d3dd6..c0b2631 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -23,6 +23,9 @@ obj-$(CONFIG_NF_NAT_IPV6) += nf_nat_ipv6.o
 nf_defrag_ipv6-y := nf_defrag_ipv6_hooks.o nf_conntrack_reasm.o
 obj-$(CONFIG_NF_DEFRAG_IPV6) += nf_defrag_ipv6.o
 
+# logging
+obj-$(CONFIG_NF_LOG_IPV6) += nf_log_ipv6.o
+
 # nf_tables
 obj-$(CONFIG_NF_TABLES_IPV6) += nf_tables_ipv6.o
 obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
diff --git a/net/ipv6/netfilter/nf_log_ipv6.c b/net/ipv6/netfilter/nf_log_ipv6.c
new file mode 100644
index 0000000..8040609
--- /dev/null
+++ b/net/ipv6/netfilter/nf_log_ipv6.c
@@ -0,0 +1,417 @@
+/* (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_ipv6/ip6_tables.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_ipv6_packet(struct nf_log_buf *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) {
+		nf_log_buf_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 " */
+	nf_log_buf_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
+
+	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
+	nf_log_buf_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) {
+			nf_log_buf_add(m, "TRUNCATED");
+			return;
+		}
+
+		/* Max length: 48 "OPT (...) " */
+		if (logflags & XT_LOG_IPOPT)
+			nf_log_buf_add(m, "OPT ( ");
+
+		switch (currenthdr) {
+		case IPPROTO_FRAGMENT: {
+			struct frag_hdr _fhdr;
+			const struct frag_hdr *fh;
+
+			nf_log_buf_add(m, "FRAG:");
+			fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
+						&_fhdr);
+			if (fh == NULL) {
+				nf_log_buf_add(m, "TRUNCATED ");
+				return;
+			}
+
+			/* Max length: 6 "65535 " */
+			nf_log_buf_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
+
+			/* Max length: 11 "INCOMPLETE " */
+			if (fh->frag_off & htons(0x0001))
+				nf_log_buf_add(m, "INCOMPLETE ");
+
+			nf_log_buf_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)
+					nf_log_buf_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 " */
+				nf_log_buf_add(m, "AH ");
+
+				if (fragment) {
+					nf_log_buf_add(m, ")");
+					return;
+				}
+
+				ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
+							&_ahdr);
+				if (ah == NULL) {
+					/*
+					 * Max length: 26 "INCOMPLETE [65535
+					 *  bytes] )"
+					 */
+					nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
+						       skb->len - ptr);
+					return;
+				}
+
+				/* Length: 15 "SPI=0xF1234567 */
+				nf_log_buf_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 " */
+				nf_log_buf_add(m, "ESP ");
+
+				if (fragment) {
+					nf_log_buf_add(m, ")");
+					return;
+				}
+
+				/*
+				 * Max length: 26 "INCOMPLETE [65535 bytes] )"
+				 */
+				eh = skb_header_pointer(skb, ptr, sizeof(_esph),
+							&_esph);
+				if (eh == NULL) {
+					nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
+						       skb->len - ptr);
+					return;
+				}
+
+				/* Length: 16 "SPI=0xF1234567 )" */
+				nf_log_buf_add(m, "SPI=0x%x )",
+					       ntohl(eh->spi));
+			}
+			return;
+		default:
+			/* Max length: 20 "Unknown Ext Hdr 255" */
+			nf_log_buf_add(m, "Unknown Ext Hdr %u", currenthdr);
+			return;
+		}
+		if (logflags & XT_LOG_IPOPT)
+			nf_log_buf_add(m, ") ");
+
+		currenthdr = hp->nexthdr;
+		ptr += hdrlen;
+	}
+
+	switch (currenthdr) {
+	case IPPROTO_TCP:
+		if (nf_log_dump_tcp_header(m, skb, currenthdr, fragment,
+					   ptr, logflags))
+			return;
+		break;
+	case IPPROTO_UDP:
+	case IPPROTO_UDPLITE:
+		if (nf_log_dump_udp_header(m, skb, currenthdr, fragment, ptr))
+			return;
+		break;
+	case IPPROTO_ICMPV6: {
+		struct icmp6hdr _icmp6h;
+		const struct icmp6hdr *ic;
+
+		/* Max length: 13 "PROTO=ICMPv6 " */
+		nf_log_buf_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) {
+			nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
+				       skb->len - ptr);
+			return;
+		}
+
+		/* Max length: 18 "TYPE=255 CODE=255 " */
+		nf_log_buf_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 " */
+			nf_log_buf_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 " */
+			nf_log_buf_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) {
+				nf_log_buf_add(m, "[");
+				dump_ipv6_packet(m, info, skb,
+						 ptr + sizeof(_icmp6h), 0);
+				nf_log_buf_add(m, "] ");
+			}
+
+			/* Max length: 10 "MTU=65535 " */
+			if (ic->icmp6_type == ICMPV6_PKT_TOOBIG) {
+				nf_log_buf_add(m, "MTU=%u ",
+					       ntohl(ic->icmp6_mtu));
+			}
+		}
+		break;
+	}
+	/* Max length: 10 "PROTO=255 " */
+	default:
+		nf_log_buf_add(m, "PROTO=%u ", currenthdr);
+	}
+
+	/* Max length: 15 "UID=4294967295 " */
+	if ((logflags & XT_LOG_UID) && recurse)
+		nf_log_dump_sk_uid_gid(m, skb->sk);
+
+	/* Max length: 16 "MARK=0xFFFFFFFF " */
+	if (recurse && skb->mark)
+		nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
+}
+
+static void dump_ipv6_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 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) {
+			nf_log_buf_add(m, "%02x", *p++);
+			for (i = 1; i < len; i++)
+				nf_log_buf_add(m, ":%02x", *p++);
+		}
+		nf_log_buf_add(m, " ");
+
+		if (dev->type == ARPHRD_SIT) {
+			const struct iphdr *iph =
+				(struct iphdr *)skb_mac_header(skb);
+			nf_log_buf_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr,
+				       &iph->daddr);
+		}
+	} else {
+		nf_log_buf_add(m, " ");
+	}
+}
+
+void nf_log_ip6_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_ipv6_mac_header(m, loginfo, skb);
+
+	dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
+
+	nf_log_buf_close(m);
+}
+EXPORT_SYMBOL_GPL(nf_log_ip6_packet);
+
+static struct nf_logger nf_ip6_logger __read_mostly = {
+	.name		= "nf_log_ipv6",
+	.type		= NF_LOG_TYPE_LOG,
+	.logfn		= nf_log_ip6_packet,
+	.me		= THIS_MODULE,
+};
+
+static int __net_init nf_log_ipv6_net_init(struct net *net)
+{
+	nf_log_set(net, NFPROTO_IPV6, &nf_ip6_logger);
+	return 0;
+}
+
+static void __net_exit nf_log_ipv6_net_exit(struct net *net)
+{
+	nf_log_unset(net, &nf_ip6_logger);
+}
+
+static struct pernet_operations nf_log_ipv6_net_ops = {
+	.init = nf_log_ipv6_net_init,
+	.exit = nf_log_ipv6_net_exit,
+};
+
+static int __init nf_log_ipv6_init(void)
+{
+	int ret;
+
+	ret = register_pernet_subsys(&nf_log_ipv6_net_ops);
+	if (ret < 0)
+		return ret;
+
+	nf_log_register(NFPROTO_IPV6, &nf_ip6_logger);
+	return 0;
+}
+
+static void __exit nf_log_ipv6_exit(void)
+{
+	unregister_pernet_subsys(&nf_log_ipv6_net_ops);
+	nf_log_unregister(&nf_ip6_logger);
+}
+
+module_init(nf_log_ipv6_init);
+module_exit(nf_log_ipv6_exit);
+
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("Netfilter IPv4 packet logging");
+MODULE_LICENSE("GPL");