/* $OpenBSD: connection.c,v 1.29 2004/06/14 09:55:41 ho Exp $	 */
/* $EOM: connection.c,v 1.28 2000/11/23 12:21:18 niklas Exp $	 */

/*
 * Copyright (c) 1999, 2000, 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 1999 Hakan Olsson.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <sys/queue.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <string.h>

#include "sysdep.h"

#include "conf.h"
#include "connection.h"
#include "doi.h"
#include "ipsec.h"

/* XXX isakmp.h only required for compare_ids().  */
#include "isakmp.h"

#include "log.h"
#include "timer.h"
#include "util.h"

/* How often should we check that connections we require to be up, are up?  */
#define CHECK_INTERVAL 60

static void     connection_passive_teardown(char *);

struct connection {
	TAILQ_ENTRY(connection) link;
	char           *name;
	struct event   *ev;
};

struct connection_passive {
	TAILQ_ENTRY(connection_passive) link;
	char           *name;
	u_int8_t       *local_id, *remote_id;
	size_t          local_sz, remote_sz;

#if 0
	/* XXX Potential additions to 'connection_passive'.  */
	char           *isakmp_peer;
	struct sa      *sa;	/* XXX "Soft" ref to active sa?  */
	struct timeval  sa_expiration;	/* XXX *sa may expire.  */
#endif
};

TAILQ_HEAD(connection_head, connection) connections;
TAILQ_HEAD(passive_head, connection_passive) connections_passive;

/*
 * This is where we setup all the connections we want there right from the
 * start.
 */
void
connection_init(void)
{
	struct conf_list *conns, *attrs;
	struct conf_list_node *conn, *attr = NULL;

	/*
	 * Passive connections normally include: all "active" connections that
	 * are not flagged "Active-Only", plus all connections listed in
	 * the 'Passive-Connections' list.
         */
	TAILQ_INIT(&connections);
	TAILQ_INIT(&connections_passive);

	conns = conf_get_list("Phase 2", "Connections");
	if (conns) {
		for (conn = TAILQ_FIRST(&conns->fields); conn;
		    conn = TAILQ_NEXT(conn, link)) {
			if (connection_setup(conn->field))
				log_print("connection_init: could not setup "
				    "\"%s\"", conn->field);

			/* XXX Break/abort here if connection_setup failed?  */

			/*
			 * XXX This code (i.e. the attribute lookup) seems
			 * like a likely candidate for factoring out into a
			 * function of its own.
		         */
			attrs = conf_get_list(conn->field, "Flags");
			if (attrs)
				for (attr = TAILQ_FIRST(&attrs->fields); attr;
				    attr = TAILQ_NEXT(attr, link))
					if (strcasecmp("active-only",
					    attr->field) == 0)
						break;
			if (!attrs || (attrs && !attr))
				if (connection_record_passive(conn->field))
					log_print("connection_init: could not "
					    "record connection \"%s\"",
					    conn->field);
			if (attrs)
				conf_free_list(attrs);

		}
		conf_free_list(conns);
	}
	conns = conf_get_list("Phase 2", "Passive-Connections");
	if (conns) {
		for (conn = TAILQ_FIRST(&conns->fields); conn;
		    conn = TAILQ_NEXT(conn, link))
			if (connection_record_passive(conn->field))
				log_print("connection_init: could not record "
				    "passive connection \"%s\"", conn->field);
		conf_free_list(conns);
	}
}

/* Check the connection in VCONN and schedule another check later.  */
static void
connection_checker(void *vconn)
{
	struct timeval  now;
	struct connection *conn = vconn;

	gettimeofday(&now, 0);
	now.tv_sec += conf_get_num("General", "check-interval",
	    CHECK_INTERVAL);
	conn->ev = timer_add_event("connection_checker",
	    connection_checker, conn, &now);
	if (!conn->ev)
		log_print("connection_checker: could not add timer event");
	sysdep_connection_check(conn->name);
}

/* Find the connection named NAME.  */
static struct connection *
connection_lookup(char *name)
{
	struct connection *conn;

	for (conn = TAILQ_FIRST(&connections); conn;
	    conn = TAILQ_NEXT(conn, link))
		if (strcasecmp(conn->name, name) == 0)
			return conn;
	return 0;
}

/* Does the connection named NAME exist?  */
int
connection_exist(char *name)
{
	return (connection_lookup(name) != 0);
}

/* Find the passive connection named NAME.  */
static struct connection_passive *
connection_passive_lookup_by_name(char *name)
{
	struct connection_passive *conn;

	for (conn = TAILQ_FIRST(&connections_passive); conn;
	    conn = TAILQ_NEXT(conn, link))
		if (strcasecmp(conn->name, name) == 0)
			return conn;
	return 0;
}

/*
 * IDs of different types cannot be the same.
 * XXX Rename to ipsec_compare_id, and move to ipsec.c ?
 */
static int
compare_ids(u_int8_t *id1, u_int8_t *id2, size_t idlen)
{
	int	id1_type, id2_type;

	id1_type = GET_ISAKMP_ID_TYPE(id1);
	id2_type = GET_ISAKMP_ID_TYPE(id2);

	return id1_type == id2_type ? memcmp(id1 + ISAKMP_ID_DATA_OFF,
	    id2 + ISAKMP_ID_DATA_OFF, idlen - ISAKMP_ID_DATA_OFF) : -1;
}

/* Find the connection named with matching IDs.  */
char *
connection_passive_lookup_by_ids(u_int8_t *id1, u_int8_t *id2)
{
	struct connection_passive *conn;

	for (conn = TAILQ_FIRST(&connections_passive); conn;
	    conn = TAILQ_NEXT(conn, link)) {
		if (!conn->remote_id)
			continue;

		/*
		 * If both IDs match what we have saved, return the name.
		 * Don't bother in which order they are.
	         */
		if ((compare_ids(id1, conn->local_id, conn->local_sz) == 0 &&
		    compare_ids(id2, conn->remote_id, conn->remote_sz) == 0) ||
		    (compare_ids(id1, conn->remote_id, conn->remote_sz) == 0 &&
		    compare_ids(id2, conn->local_id, conn->local_sz) == 0)) {
			LOG_DBG((LOG_MISC, 60,
			    "connection_passive_lookup_by_ids: "
			    "returned \"%s\"", conn->name));
			return conn->name;
		}
	}

	/*
	 * In the road warrior case, we do not know the remote ID. In that
	 * case we will just match against the local ID.
	 */
	for (conn = TAILQ_FIRST(&connections_passive); conn;
	    conn = TAILQ_NEXT(conn, link)) {
		if (!conn->remote_id)
			continue;

		if (compare_ids(id1, conn->local_id, conn->local_sz) == 0 ||
		    compare_ids(id2, conn->local_id, conn->local_sz) == 0) {
			LOG_DBG((LOG_MISC, 60,
			    "connection passive_lookup_by_ids: returned \"%s\""
			    " only matched local id", conn->name));
			return conn->name;
		}
	}
	LOG_DBG((LOG_MISC, 60,
	    "connection_passive_lookup_by_ids: no match"));
	return 0;
}

/*
 * Setup NAME to be a connection that should be up "always", i.e. if it dies,
 * for whatever reason, it should be tried to be brought up, over and over
 * again.
 */
int
connection_setup(char *name)
{
	struct connection *conn = 0;
	struct timeval  now;

	/* Check for trials to add duplicate connections.  */
	if (connection_lookup(name)) {
		LOG_DBG((LOG_MISC, 10,
		    "connection_setup: cannot add \"%s\" twice", name));
		return 0;
	}
	conn = calloc(1, sizeof *conn);
	if (!conn) {
		log_error("connection_setup: calloc (1, %lu) failed",
		    (unsigned long)sizeof *conn);
		goto fail;
	}
	conn->name = strdup(name);
	if (!conn->name) {
		log_error("connection_setup: strdup (\"%s\") failed", name);
		goto fail;
	}
	gettimeofday(&now, 0);
	conn->ev = timer_add_event("connection_checker", connection_checker,
	    conn, &now);
	if (!conn->ev) {
		log_print("connection_setup: could not add timer event");
		goto fail;
	}
	TAILQ_INSERT_TAIL(&connections, conn, link);
	return 0;

fail:
	if (conn) {
		if (conn->name)
			free(conn->name);
		free(conn);
	}
	return -1;
}

int
connection_record_passive(char *name)
{
	struct connection_passive *conn;
	char           *local_id, *remote_id;

	if (connection_passive_lookup_by_name(name)) {
		LOG_DBG((LOG_MISC, 10,
		    "connection_record_passive: cannot add \"%s\" twice",
		    name));
		return 0;
	}
	local_id = conf_get_str(name, "Local-ID");
	if (!local_id) {
		log_print("connection_record_passive: "
		    "\"Local-ID\" is missing from section [%s]", name);
		return -1;
	}
	/* If the remote id lookup fails we defer it to later */
	remote_id = conf_get_str(name, "Remote-ID");

	conn = calloc(1, sizeof *conn);
	if (!conn) {
		log_error("connection_record_passive: calloc (1, %lu) failed",
		    (unsigned long)sizeof *conn);
		return -1;
	}
	conn->name = strdup(name);
	if (!conn->name) {
		log_error("connection_record_passive: strdup (\"%s\") failed",
		    name);
		goto fail;
	}
	/* XXX IPsec DOI-specific.  */
	conn->local_id = ipsec_build_id(local_id, &conn->local_sz);
	if (!conn->local_id)
		goto fail;

	if (remote_id) {
		conn->remote_id = ipsec_build_id(remote_id, &conn->remote_sz);
		if (!conn->remote_id)
			goto fail;
	} else
		conn->remote_id = 0;

	TAILQ_INSERT_TAIL(&connections_passive, conn, link);

	LOG_DBG((LOG_MISC, 60,
	    "connection_record_passive: passive connection \"%s\" added",
	    conn->name));
	return 0;

fail:
	if (conn->local_id)
		free(conn->local_id);
	if (conn->name)
		free(conn->name);
	free(conn);
	return -1;
}

/* Remove the connection named NAME.  */
void
connection_teardown(char *name)
{
	struct connection *conn;

	conn = connection_lookup(name);
	if (!conn)
		return;

	TAILQ_REMOVE(&connections, conn, link);
	timer_remove_event(conn->ev);
	free(conn->name);
	free(conn);
}

/* Remove the passive connection named NAME.  */
static void
connection_passive_teardown(char *name)
{
	struct connection_passive *conn;

	conn = connection_passive_lookup_by_name(name);
	if (!conn)
		return;

	TAILQ_REMOVE(&connections_passive, conn, link);
	free(conn->name);
	free(conn->local_id);
	free(conn->remote_id);
	free(conn);
}

void
connection_report(void)
{
	struct connection *conn;
	struct timeval  now;
#ifdef USE_DEBUG
	struct connection_passive *pconn;
	struct doi     *doi = doi_lookup(ISAKMP_DOI_ISAKMP);
#endif

	gettimeofday(&now, 0);
	for (conn = TAILQ_FIRST(&connections); conn;
	    conn = TAILQ_NEXT(conn, link))
		LOG_DBG((LOG_REPORT, 0,
		    "connection_report: connection %s next check %ld seconds",
		    (conn->name ? conn->name : "<unnamed>"),
		    conn->ev->expiration.tv_sec - now.tv_sec));
#ifdef USE_DEBUG
	for (pconn = TAILQ_FIRST(&connections_passive); pconn;
	    pconn = TAILQ_NEXT(pconn, link))
		LOG_DBG((LOG_REPORT, 0,
		    "connection_report: passive connection %s %s", pconn->name,
		    doi->decode_ids("local_id: %s, remote_id: %s",
		    pconn->local_id, pconn->local_sz,
		    pconn->remote_id, pconn->remote_sz, 1)));
#endif
}

/* Reinitialize all connections (SIGHUP handling).  */
void
connection_reinit(void)
{
	struct connection *conn, *next;
	struct connection_passive *pconn, *pnext;

	LOG_DBG((LOG_MISC, 30,
	    "connection_reinit: reinitializing connection list"));

	/* Remove all present connections.  */
	for (conn = TAILQ_FIRST(&connections); conn; conn = next) {
		next = TAILQ_NEXT(conn, link);
		connection_teardown(conn->name);
	}

	for (pconn = TAILQ_FIRST(&connections_passive); pconn; pconn = pnext) {
		pnext = TAILQ_NEXT(pconn, link);
		connection_passive_teardown(pconn->name);
	}

	/* Setup new connections, as the (new) config directs.  */
	connection_init();
}