strongswan/src/libcharon/encoding/payloads/sa_payload.c

/*
 * Copyright (C) 2005-2010 Martin Willi
 * 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.
 */

#include <stddef.h>

#include "sa_payload.h"

#include <encoding/payloads/encodings.h>
#include <utils/linked_list.h>
#include <daemon.h>


typedef struct private_sa_payload_t private_sa_payload_t;

/**
 * Private data of an sa_payload_t object.
 */
struct private_sa_payload_t {

	/**
	 * Public sa_payload_t interface.
	 */
	sa_payload_t public;

	/**
	 * Next payload type.
	 */
	u_int8_t  next_payload;

	/**
	 * Critical flag.
	 */
	bool critical;

	/**
	 * Length of this payload.
	 */
	u_int16_t payload_length;

	/**
	 * Proposals in this payload are stored in a linked_list_t.
	 */
	linked_list_t * proposals;
};

/**
 * Encoding rules to parse or generate a IKEv2-SA Payload
 *
 * The defined offsets are the positions in a object of type
 * private_sa_payload_t.
 */
encoding_rule_t sa_payload_encodings[] = {
	/* 1 Byte next payload type, stored in the field next_payload */
	{ U_INT_8,			offsetof(private_sa_payload_t, next_payload)		},
	/* the critical bit */
	{ FLAG,				offsetof(private_sa_payload_t, critical)			},
	/* 7 Bit reserved bits, nowhere stored */
	{ RESERVED_BIT,		0													},
	{ RESERVED_BIT,		0													},
	{ RESERVED_BIT,		0													},
	{ RESERVED_BIT,		0													},
	{ RESERVED_BIT,		0													},
	{ RESERVED_BIT,		0													},
	{ RESERVED_BIT,		0													},
	/* Length of the whole SA payload*/
	{ PAYLOAD_LENGTH,	offsetof(private_sa_payload_t, payload_length)		},
	/* Proposals are stored in a proposal substructure,
	   offset points to a linked_list_t pointer */
	{ PROPOSALS,		offsetof(private_sa_payload_t, proposals)			},
};

/*
                           1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ! Next Payload  !C!  RESERVED   !         Payload Length        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                                                               !
      ~                          <Proposals>                          ~
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/

METHOD(payload_t, verify, status_t,
	private_sa_payload_t *this)
{
	int expected_number = 1, current_number;
	status_t status = SUCCESS;
	enumerator_t *enumerator;
	proposal_substructure_t *substruct;
	bool first = TRUE;

	/* check proposal numbering */
	enumerator = this->proposals->create_enumerator(this->proposals);
	while (enumerator->enumerate(enumerator, (void**)&substruct))
	{
		current_number = substruct->get_proposal_number(substruct);
		if (current_number < expected_number)
		{
			if (current_number != expected_number + 1)
			{
				DBG1(DBG_ENC, "proposal number is %d, expected %d or %d",
					 current_number, expected_number, expected_number + 1);
				status = FAILED;
				break;
			}
		}
		else if (current_number < expected_number)
		{
			DBG1(DBG_ENC, "proposal number smaller than previous");
			status = FAILED;
			break;
		}

		status = substruct->payload_interface.verify(&substruct->payload_interface);
		if (status != SUCCESS)
		{
			DBG1(DBG_ENC, "PROPOSAL_SUBSTRUCTURE verification failed");
			break;
		}
		first = FALSE;
		expected_number = current_number;
	}
	enumerator->destroy(enumerator);
	return status;
}

METHOD(payload_t, get_encoding_rules, void,
	private_sa_payload_t *this, encoding_rule_t **rules, size_t *rule_count)
{
	*rules = sa_payload_encodings;
	*rule_count = countof(sa_payload_encodings);
}

METHOD(payload_t, get_type, payload_type_t,
	private_sa_payload_t *this)
{
	return SECURITY_ASSOCIATION;
}

METHOD(payload_t, get_next_type, payload_type_t,
	private_sa_payload_t *this)
{
	return this->next_payload;
}

METHOD(payload_t, set_next_type, void,
	private_sa_payload_t *this,payload_type_t type)
{
	this->next_payload = type;
}

/**
 * recompute length of the payload.
 */
static void compute_length(private_sa_payload_t *this)
{
	enumerator_t *enumerator;
	payload_t *current;
	size_t length = SA_PAYLOAD_HEADER_LENGTH;

	enumerator = this->proposals->create_enumerator(this->proposals);
	while (enumerator->enumerate(enumerator, (void **)&current))
	{
		length += current->get_length(current);
	}
	enumerator->destroy(enumerator);

	this->payload_length = length;
}

METHOD(payload_t, get_length, size_t,
	private_sa_payload_t *this)
{
	compute_length(this);
	return this->payload_length;
}

METHOD(sa_payload_t, add_proposal, void,
	private_sa_payload_t *this, proposal_t *proposal)
{
	proposal_substructure_t *substruct, *last;
	u_int count;

	count = this->proposals->get_count(this->proposals);
	substruct = proposal_substructure_create_from_proposal(proposal);
	if (count > 0)
	{
		this->proposals->get_last(this->proposals, (void**)&last);
		/* last transform is now not anymore last one */
		last->set_is_last_proposal(last, FALSE);
	}
	substruct->set_is_last_proposal(substruct, TRUE);
	substruct->set_proposal_number(substruct, count + 1);
	this->proposals->insert_last(this->proposals, proposal);
	compute_length(this);
}

METHOD(sa_payload_t, get_proposals, linked_list_t*,
	private_sa_payload_t *this)
{
	int struct_number = 0;
	int ignore_struct_number = 0;
	enumerator_t *enumerator;
	proposal_substructure_t *substruct;
	linked_list_t *list;
	proposal_t *proposal;

	list = linked_list_create();
	/* we do not support proposals split up to two proposal substructures, as
	 * AH+ESP bundles are not supported in RFC4301 anymore.
	 * To handle such structures safely, we just skip proposals with multiple
	 * protocols.
	 */
	enumerator = this->proposals->create_enumerator(this->proposals);
	while (enumerator->enumerate(enumerator, &substruct))
	{
		/* check if a proposal has a single protocol */
		if (substruct->get_proposal_number(substruct) == struct_number)
		{
			if (ignore_struct_number < struct_number)
			{
				/* remove an already added, if first of series */
				list->remove_last(list, (void**)&proposal);
				proposal->destroy(proposal);
				ignore_struct_number = struct_number;
			}
			continue;
		}
		struct_number++;
		proposal = substruct->get_proposal(substruct);
		if (proposal)
		{
			list->insert_last(list, proposal);
		}
	}
	enumerator->destroy(enumerator);
	return list;
}

METHOD2(payload_t, sa_payload_t, destroy, void,
	private_sa_payload_t *this)
{
	this->proposals->destroy_offset(this->proposals,
									offsetof(proposal_substructure_t, destroy));
	free(this);
}

/*
 * Described in header.
 */
sa_payload_t *sa_payload_create()
{
	private_sa_payload_t *this;

	INIT(this,
		.public = {
			.payload_interface = {
				.verify = _verify,
				.get_encoding_rules = _get_encoding_rules,
				.get_length = _get_length,
				.get_next_type = _get_next_type,
				.set_next_type = _set_next_type,
				.get_type = _get_type,
				.destroy = _destroy,
			},
			.add_proposal = _add_proposal,
			.get_proposals = _get_proposals,
			.destroy = _destroy,
		},
		.next_payload = NO_PAYLOAD,
		.payload_length = SA_PAYLOAD_HEADER_LENGTH,
		.proposals = linked_list_create(),
	);
	return &this->public;
}

/*
 * Described in header.
 */
sa_payload_t *sa_payload_create_from_proposal_list(linked_list_t *proposals)
{
	private_sa_payload_t *this;
	enumerator_t *enumerator;
	proposal_t *proposal;

	this = (private_sa_payload_t*)sa_payload_create();
	enumerator = proposals->create_enumerator(proposals);
	while (enumerator->enumerate(enumerator, &proposal))
	{
		add_proposal(this, proposal);
	}
	enumerator->destroy(enumerator);

	return &this->public;
}

/*
 * Described in header.
 */
sa_payload_t *sa_payload_create_from_proposal(proposal_t *proposal)
{
	private_sa_payload_t *this;

	this = (private_sa_payload_t*)sa_payload_create();
	add_proposal(this, proposal);

	return &this->public;
}