root/include/net/netfilter/nf_log.h

#ifndef _NF_LOG_H
#define _NF_LOG_H

#include <linux/netfilter.h>

/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
 * disappear once iptables is replaced with pkttables.  Please DO NOT use them
 * for any new code! */
#define NF_LOG_TCPSEQ           0x01    /* Log TCP sequence numbers */
#define NF_LOG_TCPOPT           0x02    /* Log TCP options */
#define NF_LOG_IPOPT            0x04    /* Log IP options */
#define NF_LOG_UID              0x08    /* Log UID owning local socket */
#define NF_LOG_MASK             0x0f

enum nf_log_type {
        NF_LOG_TYPE_LOG         = 0,
        NF_LOG_TYPE_ULOG,
        NF_LOG_TYPE_MAX
};

struct nf_loginfo {
        u_int8_t type;
        union {
                struct {
                        u_int32_t copy_len;
                        u_int16_t group;
                        u_int16_t qthreshold;
                } ulog;
                struct {
                        u_int8_t level;
                        u_int8_t logflags;
                } log;
        } u;
};

typedef void nf_logfn(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 *li,
                      const char *prefix);

struct nf_logger {
        char                    *name;
        enum nf_log_type        type;
        nf_logfn                *logfn;
        struct module           *me;
};

/* Function to register/unregister log function. */
int nf_log_register(u_int8_t pf, struct nf_logger *logger);
void nf_log_unregister(struct nf_logger *logger);

void nf_log_set(struct net *net, u_int8_t pf,
                const struct nf_logger *logger);
void nf_log_unset(struct net *net, const struct nf_logger *logger);

int nf_log_bind_pf(struct net *net, u_int8_t pf,
                   const struct nf_logger *logger);
void nf_log_unbind_pf(struct net *net, u_int8_t pf);

int nf_logger_find_get(int pf, enum nf_log_type type);
void nf_logger_put(int pf, enum nf_log_type type);
void nf_logger_request_module(int pf, enum nf_log_type type);

#define MODULE_ALIAS_NF_LOGGER(family, type) \
        MODULE_ALIAS("nf-logger-" __stringify(family) "-" __stringify(type))

/* Calls the registered backend logging function */
__printf(8, 9)
void nf_log_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 *li,
                   const char *fmt, ...);

struct nf_log_buf;

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);

/* 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 */