kernel.h

This a good VPN source

/* declarations of routines that interface with the kernel's IPsec mechanism
 * Copyright (C) 1998-2001  D. Hugh Redelmeier.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * RCSID $Id: kernel.h,v 1.42 2004/06/01 14:43:20 ken Exp $
 */

extern bool no_klips;	/* don't actually use KLIPS */
extern bool can_do_IPcomp;  /* can system actually perform IPCOMP? */

#ifdef KLIPS
/* Declare eroute things early enough for uses.
 *
 * Flags are encoded above the low-order byte of verbs.
 * "real" eroutes are only outbound.  Inbound eroutes don't exist,
 * but an addflow with an INBOUND flag allows IPIP tunnels to be
 * limited to appropriate source and destination addresses.
 */

#define ERO_MASK	0xFF
#define ERO_FLAG_SHIFT	8

#define ERO_DELETE	SADB_X_DELFLOW
#define ERO_ADD	SADB_X_ADDFLOW
#define ERO_REPLACE	(SADB_X_ADDFLOW | (SADB_X_SAFLAGS_REPLACEFLOW << ERO_FLAG_SHIFT))
#define ERO_ADD_INBOUND	(SADB_X_ADDFLOW | (SADB_X_SAFLAGS_INFLOW << ERO_FLAG_SHIFT))
#define ERO_DEL_INBOUND	(SADB_X_DELFLOW | (SADB_X_SAFLAGS_INFLOW << ERO_FLAG_SHIFT))

struct pfkey_proto_info {
	int proto;
	int encapsulation;
	unsigned reqid;
};
struct sadb_msg;

struct kernel_sa {
	const ip_address *src;
	const ip_address *dst;

	const ip_subnet *src_client;
	const ip_subnet *dst_client;

	ipsec_spi_t spi;
	unsigned proto;
	unsigned satype;
	unsigned replay_window;
	unsigned reqid;

	unsigned authalg;
	unsigned authkeylen;
	char *authkey;

	unsigned encalg;
	unsigned enckeylen;
	char *enckey;

	int encapsulation;
#ifdef NAT_TRAVERSAL
	u_int16_t natt_sport, natt_dport;
	u_int8_t transid, natt_type;
	ip_address *natt_oa;
#endif
	const char *text_said;
};

struct kernel_ops {
	enum {
	        KERNEL_TYPE_NONE,
		KERNEL_TYPE_KLIPS,
		KERNEL_TYPE_LINUX,
	} type;
	bool inbound_eroute;
	bool policy_lifetime;
	int *async_fdp;

	void (*init)(void);
	void (*pfkey_register)(void);
	void (*pfkey_register_response)(const struct sadb_msg *msg);
	void (*process_queue)(void);
	void (*process_msg)(void);
	bool (*raw_eroute)(const ip_address *this_host,
			   const ip_subnet *this_client,
			   const ip_address *that_host,
			   const ip_subnet *that_client,
			   ipsec_spi_t spi,
			   unsigned int proto,
			   unsigned int transport_proto,
			   unsigned int satype,
			   const struct pfkey_proto_info *proto_info,
			   time_t use_lifetime,
			   unsigned int op,
			   const char *text_said);
	bool (*add_sa)(const struct kernel_sa *sa, bool replace);
	bool (*grp_sa)(const struct kernel_sa *sa_outer,
		       const struct kernel_sa *sa_inner);
	bool (*del_sa)(const struct kernel_sa *sa);
	ipsec_spi_t (*get_spi)(const ip_address *src,
			       const ip_address *dst,
			       int proto,
			       bool tunnel_mode,
			       unsigned reqid,
			       ipsec_spi_t min,
			       ipsec_spi_t max,
			       const char *text_said);
};


extern const struct kernel_ops *kernel_ops;

/* information from /proc/net/ipsec_eroute */

struct eroute_info {
    unsigned long count;
    ip_subnet ours;
    ip_subnet his;
    ip_address dst;
    ip_said	said;
    int         transport_proto;
    struct eroute_info *next;
};

extern struct eroute_info *orphaned_holds;

extern void show_shunt_status(void);
#endif

/* A netlink header defines EM_MAXRELSPIS, the max number of SAs in a group.
 * Is there a PF_KEY equivalent?
 */
#ifndef EM_MAXRELSPIS
# define EM_MAXRELSPIS 4	/* AH ESP IPCOMP IPIP */
#endif

extern void record_and_initiate_opportunistic(const ip_subnet *
					      , const ip_subnet *
					      , int transport_proto
					      , const char *why);

extern void init_kernel(void);

extern void scan_proc_shunts(void);

struct connection;	/* forward declaration of tag */
extern bool trap_connection(struct connection *c);
extern void unroute_connection(struct connection *c);

extern bool has_bare_hold(const ip_address *src, const ip_address *dst
    , int transport_proto);

extern bool replace_bare_shunt(const ip_address *src, const ip_address *dst
			       , policy_prio_t policy_prio
			       , ipsec_spi_t shunt_spi	/* in host order! */
			       , bool repl
			       , int transport_proto
			       , const char *why);

extern bool assign_hold(struct connection *c
			, struct spd_route *sr
 			, int transport_proto
			, const ip_address *src, const ip_address *dst);

extern ipsec_spi_t shunt_policy_spi(struct connection *c, bool prospective);


struct state;	/* forward declaration of tag */
extern ipsec_spi_t get_ipsec_spi(ipsec_spi_t avoid
				 , int proto
				 , struct spd_route *sr
				 , bool tunnel_mode);
extern ipsec_spi_t get_my_cpi(struct spd_route *sr, bool tunnel_mode);

extern bool install_inbound_ipsec_sa(struct state *st);
extern bool install_ipsec_sa(struct state *st, bool inbound_also);
extern void delete_ipsec_sa(struct state *st, bool inbound_only);
extern bool route_and_eroute(struct connection *c
			     , struct spd_route *sr
			     , struct state *st);

extern bool was_eroute_idle(struct state *st, time_t idle_max);

#ifdef NAT_TRAVERSAL
extern bool update_ipsec_sa(struct state *st);
#endif