/**
 * @file child_sa.c
 *
 * @brief Implementation of child_sa_t.
 *
 */

/*
 * Copyright (C) 2005-2007 Martin Willi
 * Copyright (C) 2006 Tobias Brunner, Daniel Roethlisberger
 * Copyright (C) 2005 Jan Hutter
 * Hochschule fuer Technik Rapperswil
 *
 * 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.
 */

#define _GNU_SOURCE
#include "child_sa.h"

#include <stdio.h>
#include <string.h>

#include <daemon.h>

ENUM(child_sa_state_names, CHILD_CREATED, CHILD_DELETING,
	"CREATED",
	"ROUTED",
	"INSTALLED",
	"REKEYING",
	"DELETING",
);

typedef struct sa_policy_t sa_policy_t;

/**
 * Struct used to store information for a policy. This
 * is needed since we must provide all this information
 * for deleting a policy...
 */
struct sa_policy_t {
	/**
	 * Traffic selector for us
	 */
	traffic_selector_t *my_ts;
	
	/**
	 * Traffic selector for other
	 */
	traffic_selector_t *other_ts;
};

typedef struct private_child_sa_t private_child_sa_t;

/**
 * Private data of a child_sa_t object.
 */
struct private_child_sa_t {
	/**
	 * Public interface of child_sa_t.
	 */
	child_sa_t public;
	
	struct {
		/** address of peer */
		host_t *addr;
		/** id of peer */
		identification_t *id;
		/** actual used SPI, 0 if unused */
		u_int32_t spi;
	} me, other;
	
	/**
	 * Allocated SPI for a ESP proposal candidates
	 */
	u_int32_t alloc_esp_spi;
	
	/**
	 * Allocated SPI for a AH proposal candidates
	 */
	u_int32_t alloc_ah_spi;
	
	/**
	 * Protocol used to protect this SA, ESP|AH
	 */
	protocol_id_t protocol;
	
	/**
	 * List containing sa_policy_t objects 
	 */
	linked_list_t *policies;
	
	/**
	 * Seperate list for local traffic selectors
	 */
	linked_list_t *my_ts;
	
	/**
	 * Seperate list for remote traffic selectors
	 */
	linked_list_t *other_ts;
	
	/**
	 * reqid used for this child_sa
	 */
	u_int32_t reqid;
	
	/**
	 * encryption algorithm used for this SA
	 */
	algorithm_t encryption;
	
	/**
	 * integrity protection algorithm used for this SA
	 */
	algorithm_t integrity;
	
	/**
	 * time, on which SA was installed
	 */
	time_t install_time;
	
	/**
	 * absolute time when rekeying is sceduled
	 */
	time_t rekey_time;
	
	/**
	 * state of the CHILD_SA
	 */
	child_sa_state_t state;

	/**
	 * Specifies if UDP encapsulation is enabled (NAT traversal)
	 */
	bool encap;
	
	/**
	 * mode this SA uses, tunnel/transport
	 */
	mode_t mode;
	
	/**
	 * virtual IP assinged to local host
	 */
	host_t *virtual_ip;
	
	/**
	 * config used to create this child
	 */
	child_cfg_t *config;
	
	/**
	 * cached interface name for iptables
	 */
	char *iface;
};

/**
 * Implementation of child_sa_t.get_name.
 */
static char *get_name(private_child_sa_t *this)
{
	return this->config->get_name(this->config);
}

/**
 * Implements child_sa_t.get_reqid
 */
static u_int32_t get_reqid(private_child_sa_t *this)
{
	return this->reqid;
}
	
/**
 * Implements child_sa_t.get_spi
 */
u_int32_t get_spi(private_child_sa_t *this, bool inbound)
{
	if (inbound)
	{
		return this->me.spi;
	}
	return this->other.spi;
}

/**
 * Implements child_sa_t.get_protocol
 */
protocol_id_t get_protocol(private_child_sa_t *this)
{
	return this->protocol;
}

/**
 * Implements child_sa_t.get_state
 */
static child_sa_state_t get_state(private_child_sa_t *this)
{
	return this->state;
}

/**
 * Implements child_sa_t.get_config
 */
static child_cfg_t* get_config(private_child_sa_t *this)
{
	return this->config;
}

/**
 * Implementation of child_sa_t.get_stats.
 */
static void get_stats(private_child_sa_t *this, mode_t *mode,
					  encryption_algorithm_t *encr_algo, size_t *encr_len,
					  integrity_algorithm_t *int_algo, size_t *int_len,
					  u_int32_t *rekey, u_int32_t *use_in, u_int32_t *use_out,
					  u_int32_t *use_fwd)
{
	sa_policy_t *policy;
	iterator_t *iterator;
	u_int32_t in = 0, out = 0, fwd = 0, time;
	
	iterator = this->policies->create_iterator(this->policies, TRUE);
	while (iterator->iterate(iterator, (void**)&policy))
	{

		if (charon->kernel_interface->query_policy(charon->kernel_interface,
				policy->other_ts, policy->my_ts, POLICY_IN, &time) == SUCCESS)
		{
			in = max(in, time);
		}
		if (charon->kernel_interface->query_policy(charon->kernel_interface,
				policy->my_ts, policy->other_ts, POLICY_OUT, &time) == SUCCESS)
		{
			out = max(out, time);
		}
		if (charon->kernel_interface->query_policy(charon->kernel_interface,
				policy->other_ts, policy->my_ts, POLICY_FWD, &time) == SUCCESS)
		{
			fwd = max(fwd, time);
		}
	}
	iterator->destroy(iterator);

	*mode = this->mode;
	*encr_algo = this->encryption.algorithm;
	*encr_len = this->encryption.key_size;
	*int_algo = this->integrity.algorithm;
	*int_len = this->integrity.key_size;
	*rekey = this->rekey_time;
	*use_in = in;
	*use_out = out;
	*use_fwd = fwd;
}

/**
 * Run the up/down script
 */
static void updown(private_child_sa_t *this, bool up)
{
	sa_policy_t *policy;
	iterator_t *iterator;
	char *script;
	
	script = this->config->get_updown(this->config);
	
	if (script == NULL)
	{
		return;
	}
	
	iterator = this->policies->create_iterator(this->policies, TRUE);
	while (iterator->iterate(iterator, (void**)&policy))
	{
		char command[1024];
		char *my_client, *other_client, *my_client_mask, *other_client_mask;
		char *pos, *virtual_ip;
		FILE *shell;

		/* get subnet/bits from string */
		asprintf(&my_client, "%R", policy->my_ts);
		pos = strchr(my_client, '/');
		*pos = '\0';
		my_client_mask = pos + 1;
		pos = strchr(my_client_mask, '[');
		if (pos)
		{
			*pos = '\0';
		}
		asprintf(&other_client, "%R", policy->other_ts);
		pos = strchr(other_client, '/');
		*pos = '\0';
		other_client_mask = pos + 1;
		pos = strchr(other_client_mask, '[');
		if (pos)
		{
			*pos = '\0';
		}

		if (this->virtual_ip)
		{
			asprintf(&virtual_ip, "PLUTO_MY_SOURCEIP='%H' ",
		        		 this->virtual_ip);
		}
		else
		{
			asprintf(&virtual_ip, "");
		}

		/* we cache the iface name, as it may not be available when
		 * the SA gets deleted */
		if (up)
		{
			free(this->iface); 
			this->iface = charon->kernel_interface->get_interface(
								charon->kernel_interface, this->me.addr);
		}
		
		/* build the command with all env variables.
		 * TODO: PLUTO_PEER_CA and PLUTO_NEXT_HOP are currently missing
		 */
		snprintf(command, sizeof(command),
				 "2>&1 "
				"PLUTO_VERSION='1.1' "
				"PLUTO_VERB='%s%s%s' "
				"PLUTO_CONNECTION='%s' "
				"PLUTO_INTERFACE='%s' "
				"PLUTO_REQID='%u' "
				"PLUTO_ME='%H' "
				"PLUTO_MY_ID='%D' "
				"PLUTO_MY_CLIENT='%s/%s' "
				"PLUTO_MY_CLIENT_NET='%s' "
				"PLUTO_MY_CLIENT_MASK='%s' "
				"PLUTO_MY_PORT='%u' "
				"PLUTO_MY_PROTOCOL='%u' "
				"PLUTO_PEER='%H' "
				"PLUTO_PEER_ID='%D' "
				"PLUTO_PEER_CLIENT='%s/%s' "
				"PLUTO_PEER_CLIENT_NET='%s' "
				"PLUTO_PEER_CLIENT_MASK='%s' "
				"PLUTO_PEER_PORT='%u' "
				"PLUTO_PEER_PROTOCOL='%u' "
				"%s"
				"%s"
				"%s",
				 up ? "up" : "down",
				 policy->my_ts->is_host(policy->my_ts,
							this->me.addr) ? "-host" : "-client",
				 this->me.addr->get_family(this->me.addr) == AF_INET ? "" : "-ipv6",
				 this->config->get_name(this->config),
				 this->iface ? this->iface : "unknown",
				 this->reqid,
				 this->me.addr,
				 this->me.id,
				 my_client, my_client_mask,
				 my_client, my_client_mask,
				 policy->my_ts->get_from_port(policy->my_ts),
				 policy->my_ts->get_protocol(policy->my_ts),
				 this->other.addr,
				 this->other.id,
				 other_client, other_client_mask,
				 other_client, other_client_mask,
				 policy->other_ts->get_from_port(policy->other_ts),
				 policy->other_ts->get_protocol(policy->other_ts),
				 virtual_ip,
				 this->config->get_hostaccess(this->config) ?
				 	"PLUTO_HOST_ACCESS='1' " : "",
				 script);
		free(my_client);
		free(other_client);
		free(virtual_ip);
		
		DBG3(DBG_CHD, "running updown script: %s", command);
		shell = popen(command, "r");

		if (shell == NULL)
		{
			DBG1(DBG_CHD, "could not execute updown script '%s'", script);
			return;
		}
		
		while (TRUE)
		{
			char resp[128];
			
			if (fgets(resp, sizeof(resp), shell) == NULL)
			{
				if (ferror(shell))
				{
					DBG1(DBG_CHD, "error reading output from updown script");
					return;
				}
				else
				{
					break;
				}
			}
			else
			{
				char *e = resp + strlen(resp);
				if (e > resp && e[-1] == '\n')
				{	/* trim trailing '\n' */
					e[-1] = '\0';
				}
				DBG1(DBG_CHD, "updown: %s", resp);
			}
		}
		pclose(shell);
	}
	iterator->destroy(iterator);
}

/**
 * Implements child_sa_t.set_state
 */
static void set_state(private_child_sa_t *this, child_sa_state_t state)
{
	this->state = state;
	if (state == CHILD_INSTALLED)
	{
		updown(this, TRUE);
	}
}

/**
 * Allocate SPI for a single proposal
 */
static status_t alloc_proposal(private_child_sa_t *this, proposal_t *proposal)
{
	protocol_id_t protocol = proposal->get_protocol(proposal);
		
	if (protocol == PROTO_AH)
	{
		/* get a new spi for AH, if not already done */
		if (this->alloc_ah_spi == 0)
		{
			if (charon->kernel_interface->get_spi(
						 charon->kernel_interface, 
						 this->other.addr, this->me.addr,
						 PROTO_AH, this->reqid,
						 &this->alloc_ah_spi) != SUCCESS)
			{
				return FAILED;
			}
		}
		proposal->set_spi(proposal, this->alloc_ah_spi);
	}
	if (protocol == PROTO_ESP)
	{
		/* get a new spi for ESP, if not already done */
		if (this->alloc_esp_spi == 0)
		{
			if (charon->kernel_interface->get_spi(
						 charon->kernel_interface,
						 this->other.addr, this->me.addr,
						 PROTO_ESP, this->reqid,
						 &this->alloc_esp_spi) != SUCCESS)
			{
				return FAILED;
			}
		}
		proposal->set_spi(proposal, this->alloc_esp_spi);
	}
	return SUCCESS;
}


/**
 * Implements child_sa_t.alloc
 */
static status_t alloc(private_child_sa_t *this, linked_list_t *proposals)
{
	iterator_t *iterator;
	proposal_t *proposal;
	
	/* iterator through proposals to update spis */
	iterator = proposals->create_iterator(proposals, TRUE);
	while(iterator->iterate(iterator, (void**)&proposal))
	{
		if (alloc_proposal(this, proposal) != SUCCESS)
		{
			iterator->destroy(iterator);
			return FAILED;
		}
	}
	iterator->destroy(iterator);
	return SUCCESS;
}

static status_t install(private_child_sa_t *this, proposal_t *proposal,
						mode_t mode, prf_plus_t *prf_plus, bool mine)
{
	u_int32_t spi, soft, hard;;
	algorithm_t *enc_algo, *int_algo;
	algorithm_t enc_algo_none = {ENCR_UNDEFINED, 0};
	algorithm_t int_algo_none = {AUTH_UNDEFINED, 0};
	host_t *src;
	host_t *dst;
	status_t status;
	
	this->protocol = proposal->get_protocol(proposal);
	
	/* now we have to decide which spi to use. Use self allocated, if "mine",
	 * or the one in the proposal, if not "mine" (others). Additionally,
	 * source and dest host switch depending on the role */
	if (mine)
	{
		/* if we have allocated SPIs for AH and ESP, we must delete the unused
		 * one. */
		if (this->protocol == PROTO_ESP)
		{
			this->me.spi = this->alloc_esp_spi;
			if (this->alloc_ah_spi)
			{
				charon->kernel_interface->del_sa(charon->kernel_interface, this->me.addr, 
						this->alloc_ah_spi, PROTO_AH);
			}
		}
		else
		{
			this->me.spi = this->alloc_ah_spi;
			if (this->alloc_esp_spi)
			{
				charon->kernel_interface->del_sa(charon->kernel_interface, this->me.addr, 
						this->alloc_esp_spi, PROTO_ESP);
			}
		}
		spi = this->me.spi;
		dst = this->me.addr;
		src = this->other.addr;
	}
	else
	{
		this->other.spi = proposal->get_spi(proposal);
		spi = this->other.spi;
		src = this->me.addr;
		dst = this->other.addr;
	}
	
	DBG2(DBG_CHD, "adding %s %N SA", mine ? "inbound" : "outbound",
		 protocol_id_names, this->protocol);
	
	/* select encryption algo */
	if (proposal->get_algorithm(proposal, ENCRYPTION_ALGORITHM, &enc_algo))
	{
		DBG2(DBG_CHD, "  using %N for encryption",
			 encryption_algorithm_names, enc_algo->algorithm);
	}
	else
	{
		enc_algo = &enc_algo_none;
	}
	
	/* select integrity algo */
	if (proposal->get_algorithm(proposal, INTEGRITY_ALGORITHM, &int_algo))
	{
		DBG2(DBG_CHD, "  using %N for integrity",
			 integrity_algorithm_names, int_algo->algorithm);
	}
	else
	{
		int_algo = &int_algo_none;
	}
	
	soft = this->config->get_lifetime(this->config, TRUE);
	hard = this->config->get_lifetime(this->config, FALSE);
	
	/* send SA down to the kernel */
	DBG2(DBG_CHD, "  SPI 0x%.8x, src %H dst %H", ntohl(spi), src, dst);
	status = charon->kernel_interface->add_sa(charon->kernel_interface,
											  src, dst, spi, this->protocol,
											  this->reqid, mine ? soft : 0,
											  hard, enc_algo, int_algo,
											  prf_plus, mode, this->encap, mine);
	
	this->encryption = *enc_algo;
	this->integrity = *int_algo;
	this->install_time = time(NULL);
	this->rekey_time = this->install_time + soft;
	
	return status;
}

static status_t add(private_child_sa_t *this, proposal_t *proposal, 
					mode_t mode, prf_plus_t *prf_plus)
{
	u_int32_t outbound_spi, inbound_spi;
	
	/* backup outbound spi, as alloc overwrites it */
	outbound_spi = proposal->get_spi(proposal);
	
	/* get SPIs inbound SAs */
	if (alloc_proposal(this, proposal) != SUCCESS)
	{
		return FAILED;
	}
	inbound_spi = proposal->get_spi(proposal);
	
	/* install inbound SAs */
	if (install(this, proposal, mode, prf_plus, TRUE) != SUCCESS)
	{
		return FAILED;
	}
	
	/* install outbound SAs, restore spi*/
	proposal->set_spi(proposal, outbound_spi);
	if (install(this, proposal, mode, prf_plus, FALSE) != SUCCESS)
	{
		return FAILED;
	}
	proposal->set_spi(proposal, inbound_spi);
	
	return SUCCESS;
}

static status_t update(private_child_sa_t *this, proposal_t *proposal,
					   mode_t mode, prf_plus_t *prf_plus)
{
	u_int32_t inbound_spi;
	
	/* backup received spi, as install() overwrites it */
	inbound_spi = proposal->get_spi(proposal);
	
	/* install outbound SAs */
	if (install(this, proposal, mode, prf_plus, FALSE) != SUCCESS)
	{
		return FAILED;
	}
	
	/* restore spi */
	proposal->set_spi(proposal, inbound_spi);
	/* install inbound SAs */
	if (install(this, proposal, mode, prf_plus, TRUE) != SUCCESS)
	{
		return FAILED;
	}
	
	return SUCCESS;
}

static status_t add_policies(private_child_sa_t *this,
							 linked_list_t *my_ts_list,
							 linked_list_t *other_ts_list, mode_t mode)
{
	iterator_t *my_iter, *other_iter;
	traffic_selector_t *my_ts, *other_ts;
	/* use low prio for ROUTED policies */
	bool high_prio = (this->state != CHILD_CREATED);
	
	/* iterate over both lists */
	my_iter = my_ts_list->create_iterator(my_ts_list, TRUE);
	other_iter = other_ts_list->create_iterator(other_ts_list, TRUE);
	while (my_iter->iterate(my_iter, (void**)&my_ts))
	{
		other_iter->reset(other_iter);
		while (other_iter->iterate(other_iter, (void**)&other_ts))
		{
			/* set up policies for every entry in my_ts_list to every entry in other_ts_list */
			status_t status;
			sa_policy_t *policy;
			
			if (my_ts->get_type(my_ts) != other_ts->get_type(other_ts))
			{
				DBG2(DBG_CHD,
					 "CHILD_SA policy uses two different IP families - ignored");
				continue;
			}
			
			/* only set up policies if protocol matches, or if one is zero (any) */
			if (my_ts->get_protocol(my_ts) != other_ts->get_protocol(other_ts) &&
				my_ts->get_protocol(my_ts) && other_ts->get_protocol(other_ts))
			{
				DBG2(DBG_CHD,
					 "CHILD_SA policy uses two different protocols - ignored");
				continue;
			}
			
			/* install 3 policies: out, in and forward */
			status = charon->kernel_interface->add_policy(charon->kernel_interface,
					this->me.addr, this->other.addr, my_ts, other_ts, POLICY_OUT,
					this->protocol, this->reqid, high_prio, mode);
			
			status |= charon->kernel_interface->add_policy(charon->kernel_interface,
					this->other.addr, this->me.addr, other_ts, my_ts, POLICY_IN,
					this->protocol, this->reqid, high_prio, mode);
			
			status |= charon->kernel_interface->add_policy(charon->kernel_interface,
					this->other.addr, this->me.addr, other_ts, my_ts, POLICY_FWD,
					this->protocol, this->reqid, high_prio, mode);
			
			if (status != SUCCESS)
			{
				my_iter->destroy(my_iter);
				other_iter->destroy(other_iter);
				return status;
			}
			
			/* store policy to delete/update them later */
			policy = malloc_thing(sa_policy_t);
			policy->my_ts = my_ts->clone(my_ts);
			policy->other_ts = other_ts->clone(other_ts);
			this->policies->insert_last(this->policies, policy);
			/* add to separate list to query them via get_*_traffic_selectors() */
			this->my_ts->insert_last(this->my_ts, policy->my_ts);
			this->other_ts->insert_last(this->other_ts, policy->other_ts);
		}
	}
	my_iter->destroy(my_iter);
	other_iter->destroy(other_iter);
	
	/* switch to routed state if no SAD entry set up */
	if (this->state == CHILD_CREATED)
	{
		this->state = CHILD_ROUTED;
	}
	/* needed to update hosts */
	this->mode = mode;
	return SUCCESS;
}

/**
 * Implementation of child_sa_t.get_traffic_selectors.
 */
static linked_list_t *get_traffic_selectors(private_child_sa_t *this, bool local)
{
	if (local)
	{
		return this->my_ts;
	}
	return this->other_ts;
}

/**
 * Implementation of child_sa_t.get_use_time
 */
static status_t get_use_time(private_child_sa_t *this, bool inbound, time_t *use_time)
{
	iterator_t *iterator;
	sa_policy_t *policy;
	status_t status = FAILED;
	
	*use_time = UNDEFINED_TIME;

	iterator = this->policies->create_iterator(this->policies, TRUE);
	while (iterator->iterate(iterator, (void**)&policy))
	{
		if (inbound) 
		{
			time_t in = UNDEFINED_TIME, fwd = UNDEFINED_TIME;
			
			status = charon->kernel_interface->query_policy(
									charon->kernel_interface,
									policy->other_ts, policy->my_ts,
									POLICY_IN, (u_int32_t*)&in);
			status |= charon->kernel_interface->query_policy(
									charon->kernel_interface,
									policy->other_ts, policy->my_ts,
									POLICY_FWD, (u_int32_t*)&fwd);
			*use_time = max(in, fwd);
		}
		else
		{
			status = charon->kernel_interface->query_policy(
									charon->kernel_interface,
									policy->my_ts, policy->other_ts, 
									POLICY_OUT, (u_int32_t*)use_time);
		}
	}
	iterator->destroy(iterator);
	return status;
}

/**
 * Implementation of child_sa_t.update_hosts.
 */
static status_t update_hosts(private_child_sa_t *this, 
							 host_t *me, host_t *other, bool encap) 
{
	/* anything changed at all? */
	if (me->equals(me, this->me.addr) && 
		other->equals(other, this->other.addr) && this->encap == encap)
	{
		return SUCCESS;
	}
	/* run updown script to remove iptables rules */
	updown(this, FALSE);
	
	this->encap = encap;
	
	/* update our (initator) SAs */
	charon->kernel_interface->update_sa(charon->kernel_interface, this->me.spi,
			this->protocol, this->other.addr, this->me.addr, other, me, encap);
	/* update his (responder) SAs */
	charon->kernel_interface->update_sa(charon->kernel_interface, this->other.spi, 
			this->protocol, this->me.addr, this->other.addr, me, other, encap);
	
	/* update policies */
	if (!me->ip_equals(me, this->me.addr) ||
		!other->ip_equals(other, this->other.addr))
	{
		iterator_t *iterator;
		sa_policy_t *policy;
		
		/* always use high priorities, as hosts getting updated are INSTALLED */
		iterator = this->policies->create_iterator(this->policies, TRUE);
		while (iterator->iterate(iterator, (void**)&policy))
		{
			/* remove old policies first */
			charon->kernel_interface->del_policy(charon->kernel_interface,
								policy->my_ts, policy->other_ts, POLICY_OUT);
			charon->kernel_interface->del_policy(charon->kernel_interface,
								policy->other_ts, policy->my_ts,  POLICY_IN);
			charon->kernel_interface->del_policy(charon->kernel_interface,
								policy->other_ts, policy->my_ts, POLICY_FWD);
		
			/* check wether we have to update a "dynamic" traffic selector */
			if (!me->ip_equals(me, this->me.addr) &&
				policy->my_ts->is_host(policy->my_ts, this->me.addr))
			{
				policy->my_ts->set_address(policy->my_ts, me);
			}
			if (!other->ip_equals(other, this->other.addr) &&
				policy->other_ts->is_host(policy->other_ts, this->other.addr))
			{
				policy->other_ts->set_address(policy->other_ts, other);
			}
			
			/* we reinstall the virtual IP to handle interface romaing
			 * correctly */
			if (this->virtual_ip)
			{
				charon->kernel_interface->del_ip(charon->kernel_interface,
												 this->virtual_ip);
				charon->kernel_interface->add_ip(charon->kernel_interface,
												 this->virtual_ip, me);
			}
		
			/* reinstall updated policies */
			charon->kernel_interface->add_policy(charon->kernel_interface,
					me, other, policy->my_ts, policy->other_ts, POLICY_OUT,
					this->protocol,	this->reqid, TRUE, this->mode);
			charon->kernel_interface->add_policy(charon->kernel_interface, 
					other, me, policy->other_ts, policy->my_ts, POLICY_IN,
					this->protocol, this->reqid, TRUE, this->mode);
			charon->kernel_interface->add_policy(charon->kernel_interface,
					other, me, policy->other_ts, policy->my_ts, POLICY_FWD,
					this->protocol, this->reqid, TRUE, this->mode);
		}
		iterator->destroy(iterator);
	}

	/* apply hosts */
	if (!me->equals(me, this->me.addr))
	{
		this->me.addr->destroy(this->me.addr);
		this->me.addr = me->clone(me);
	}
	if (!other->equals(other, this->other.addr))
	{
		this->other.addr->destroy(this->other.addr);
		this->other.addr = other->clone(other);
	}
	
	/* install new iptables rules */
	updown(this, TRUE);
	
	return SUCCESS;
}

/**
 * Implementation of child_sa_t.set_virtual_ip.
 */
static void set_virtual_ip(private_child_sa_t *this, host_t *ip)
{
	this->virtual_ip = ip->clone(ip);
}

/**
 * Implementation of child_sa_t.destroy.
 */
static void destroy(private_child_sa_t *this)
{
	sa_policy_t *policy;
	
	if (this->state == CHILD_DELETING || this->state == CHILD_INSTALLED)
	{
		updown(this, FALSE);
	}
	
	/* delete SAs in the kernel, if they are set up */
	if (this->me.spi)
	{
		charon->kernel_interface->del_sa(charon->kernel_interface,
										 this->me.addr, this->me.spi, this->protocol);
	}
	if (this->alloc_esp_spi && this->alloc_esp_spi != this->me.spi)
	{
		charon->kernel_interface->del_sa(charon->kernel_interface,
										 this->me.addr, this->alloc_esp_spi, PROTO_ESP);
	}
	if (this->alloc_ah_spi && this->alloc_ah_spi != this->me.spi)
	{
		charon->kernel_interface->del_sa(charon->kernel_interface,
										 this->me.addr, this->alloc_ah_spi, PROTO_AH);
	}
	if (this->other.spi)
	{
		charon->kernel_interface->del_sa(charon->kernel_interface,
										 this->other.addr, this->other.spi, this->protocol);
	}
	
	/* delete all policies in the kernel */
	while (this->policies->remove_last(this->policies, (void**)&policy) == SUCCESS)
	{
		/* let rekeyed policies, as they are used by another child_sa */
		charon->kernel_interface->del_policy(charon->kernel_interface,
											 policy->my_ts, policy->other_ts,
											 POLICY_OUT);
		
		charon->kernel_interface->del_policy(charon->kernel_interface,
											 policy->other_ts, policy->my_ts,
											 POLICY_IN);
		
		charon->kernel_interface->del_policy(charon->kernel_interface,
											 policy->other_ts, policy->my_ts,
											 POLICY_FWD);
		policy->my_ts->destroy(policy->my_ts);
		policy->other_ts->destroy(policy->other_ts);
		free(policy);
	}
	this->policies->destroy(this->policies);
	
	this->my_ts->destroy(this->my_ts);
	this->other_ts->destroy(this->other_ts);
	this->me.addr->destroy(this->me.addr);
	this->other.addr->destroy(this->other.addr);
	this->me.id->destroy(this->me.id);
	this->other.id->destroy(this->other.id);
	this->config->destroy(this->config);
	free(this->iface);
	DESTROY_IF(this->virtual_ip);
	free(this);
}

/*
 * Described in header.
 */
child_sa_t * child_sa_create(host_t *me, host_t* other,
							 identification_t *my_id, identification_t *other_id,
							 child_cfg_t *config, u_int32_t rekey, bool encap)
{
	static u_int32_t reqid = 0;
	private_child_sa_t *this = malloc_thing(private_child_sa_t);

	/* public functions */
	this->public.get_name = (char*(*)(child_sa_t*))get_name;
	this->public.get_reqid = (u_int32_t(*)(child_sa_t*))get_reqid;
	this->public.get_spi = (u_int32_t(*)(child_sa_t*, bool))get_spi;
	this->public.get_protocol = (protocol_id_t(*)(child_sa_t*))get_protocol;
	this->public.get_stats = (void(*)(child_sa_t*, mode_t*,encryption_algorithm_t*,size_t*,integrity_algorithm_t*,size_t*,u_int32_t*,u_int32_t*,u_int32_t*,u_int32_t*))get_stats;
	this->public.alloc = (status_t(*)(child_sa_t*,linked_list_t*))alloc;
	this->public.add = (status_t(*)(child_sa_t*,proposal_t*,mode_t,prf_plus_t*))add;
	this->public.update = (status_t(*)(child_sa_t*,proposal_t*,mode_t,prf_plus_t*))update;
	this->public.update_hosts = (status_t (*)(child_sa_t*,host_t*,host_t*,bool))update_hosts;
	this->public.add_policies = (status_t (*)(child_sa_t*, linked_list_t*,linked_list_t*,mode_t))add_policies;
	this->public.get_traffic_selectors = (linked_list_t*(*)(child_sa_t*,bool))get_traffic_selectors;
	this->public.get_use_time = (status_t (*)(child_sa_t*,bool,time_t*))get_use_time;
	this->public.set_state = (void(*)(child_sa_t*,child_sa_state_t))set_state;
	this->public.get_state = (child_sa_state_t(*)(child_sa_t*))get_state;
	this->public.get_config = (child_cfg_t*(*)(child_sa_t*))get_config;
	this->public.set_virtual_ip = (void(*)(child_sa_t*,host_t*))set_virtual_ip;
	this->public.destroy = (void(*)(child_sa_t*))destroy;

	/* private data */
	this->me.addr = me->clone(me);
	this->other.addr = other->clone(other);
	this->me.id = my_id->clone(my_id);
	this->other.id = other_id->clone(other_id);
	this->me.spi = 0;
	this->other.spi = 0;
	this->alloc_ah_spi = 0;
	this->alloc_esp_spi = 0;
	this->encap = encap;
	this->state = CHILD_CREATED;
	/* reuse old reqid if we are rekeying an existing CHILD_SA */
	this->reqid = rekey ? rekey : ++reqid;
	this->encryption.algorithm = ENCR_UNDEFINED;
	this->encryption.key_size = 0;
	this->integrity.algorithm = AUTH_UNDEFINED;
	this->encryption.key_size = 0;
	this->policies = linked_list_create();
	this->my_ts = linked_list_create();
	this->other_ts = linked_list_create();
	this->protocol = PROTO_NONE;
	this->mode = MODE_TUNNEL;
	this->virtual_ip = NULL;
	this->iface = NULL;
	this->config = config;
	config->get_ref(config);
	
	return &this->public;
}