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/*
* Copyright (C) 2008 Martin Willi
* 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.
*
* $Id$
*/
#include "cert_cache.h"
#include <daemon.h>
#include <utils/linked_list.h>
#define CACHE_LIMIT 30
typedef struct private_cert_cache_t private_cert_cache_t;
typedef struct relation_t relation_t;
/**
* private data of cert_cache
*/
struct private_cert_cache_t {
/**
* public functions
*/
cert_cache_t public;
/**
* list of trusted subject-issuer relations, as relation_t
*/
linked_list_t *relations;
};
/**
* A trusted relation between subject and issuer
*/
struct relation_t {
/** subject of this relation */
certificate_t *subject;
/** issuer of this relation */
certificate_t *issuer;
/** time of last use */
time_t last_use;
};
/**
* destroy a relation_t structure
*/
static void relation_destroy(relation_t *this)
{
this->subject->destroy(this->subject);
this->issuer->destroy(this->issuer);
free(this);
}
/**
* Implementation of cert_cache_t.issued_by.
*/
static bool issued_by(private_cert_cache_t *this,
certificate_t *subject, certificate_t *issuer)
{
relation_t *found = NULL, *current, *oldest = NULL;
enumerator_t *enumerator;
/* lookup cache */
enumerator = this->relations->create_enumerator(this->relations);
while (enumerator->enumerate(enumerator, ¤t))
{
if (current->subject == subject && current->issuer == issuer)
{
current->last_use = time(NULL);
found = current;
break;
}
if (oldest == NULL || oldest->last_use <= current->last_use)
{
oldest = current;
}
}
enumerator->destroy(enumerator);
if (found)
{
return TRUE;
}
/* no cache hit, check signature */
if (!subject->issued_by(subject, issuer))
{
return FALSE;
}
/* cache if good, respect cache limit */
found = malloc_thing(relation_t);
found->subject = subject->get_ref(subject);
found->issuer = issuer->get_ref(issuer);
found->last_use = time(NULL);
if (this->relations->get_count(this->relations) > CACHE_LIMIT && oldest)
{
this->relations->remove(this->relations, oldest, NULL);
relation_destroy(oldest);
}
this->relations->insert_last(this->relations, found);
return TRUE;
}
/**
* data associated to a cert enumeration
*/
typedef struct {
/** type of requested certificate */
certificate_type_t cert;
/** type of requested key */
key_type_t key;
/** ID to get a cert from */
identification_t *id;
} cert_data_t;
/**
* filter function for certs enumerator
*/
static bool certs_filter(cert_data_t *data, relation_t **in, certificate_t **out)
{
public_key_t *public;
certificate_t *cert;
cert = (*in)->subject;
if (data->key == KEY_ANY && data->id &&
(data->cert == CERT_ANY || data->cert == CERT_X509_CRL) &&
cert->get_type(cert) == CERT_X509_CRL)
{ /* CRL lookup is done using issuer/authkeyidentifier */
if (cert->has_issuer(cert, data->id))
{
*out = cert;
return TRUE;
}
}
if ((data->cert == CERT_ANY || cert->get_type(cert) == data->cert) &&
(!data->id || cert->has_subject(cert, data->id)))
{
if (data->key == KEY_ANY)
{
*out = cert;
return TRUE;
}
public = cert->get_public_key(cert);
if (public)
{
if (public->get_type(public) == data->key)
{
public->destroy(public);
*out = cert;
return TRUE;
}
public->destroy(public);
}
}
return FALSE;
}
/**
* implementation of credential_set_t.create_cert_enumerator
*/
static enumerator_t *create_enumerator(private_cert_cache_t *this,
certificate_type_t cert, key_type_t key,
identification_t *id, bool trusted)
{
cert_data_t *data;
if (trusted)
{
return NULL;
}
data = malloc_thing(cert_data_t);
data->cert = cert;
data->key = key;
data->id = id;
return enumerator_create_filter(
this->relations->create_enumerator(this->relations),
(void*)certs_filter, data, (void*)free);
}
/**
* Implementation of cert_cache_t.flush.
*/
static void flush(private_cert_cache_t *this, certificate_type_t type)
{
enumerator_t *enumerator;
relation_t *relation;
enumerator = this->relations->create_enumerator(this->relations);
while (enumerator->enumerate(enumerator, &relation))
{
if (type == CERT_ANY ||
type == relation->subject->get_type(relation->subject))
{
this->relations->remove_at(this->relations, enumerator);
relation_destroy(relation);
}
}
enumerator->destroy(enumerator);
}
/**
* Implementation of cert_cache_t.destroy
*/
static void destroy(private_cert_cache_t *this)
{
this->relations->destroy_function(this->relations, (void*)relation_destroy);
free(this);
}
/*
* see header file
*/
cert_cache_t *cert_cache_create()
{
private_cert_cache_t *this = malloc_thing(private_cert_cache_t);
this->public.set.create_private_enumerator = (void*)return_null;
this->public.set.create_cert_enumerator = (void*)create_enumerator;
this->public.set.create_shared_enumerator = (void*)return_null;
this->public.set.create_cdp_enumerator = (void*)return_null;
this->public.issued_by = (bool(*)(cert_cache_t*, certificate_t *subject, certificate_t *issuer))issued_by;
this->public.flush = (void(*)(cert_cache_t*, certificate_type_t type))flush;
this->public.destroy = (void(*)(cert_cache_t*))destroy;
this->relations = linked_list_create();
return &this->public;
}
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