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>

Author: ummakynes

include/net/netfilter/nf_log.h

@@ -78,4 +78,32 @@ struct nf_log_buf *nf_log_buf_open(void);
 __printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...);
 void nf_log_buf_close(struct nf_log_buf *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);
+
+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);
+
+/* common logging functions */
+int nf_log_dump_udp_header(struct nf_log_buf *m, const struct sk_buff *skb,
+			   u8 proto, int fragment, unsigned int offset);
+int nf_log_dump_tcp_header(struct nf_log_buf *m, const struct sk_buff *skb,
+			   u8 proto, int fragment, unsigned int offset,
+			   unsigned int logflags);
+void nf_log_dump_sk_uid_gid(struct nf_log_buf *m, struct sock *sk);
+void nf_log_dump_packet_common(struct nf_log_buf *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);
+
 #endif /* _NF_LOG_H */

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"

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