/* 
 * $Id: auth_mod.c,v 1.7 2006/05/07 20:48:51 miconda Exp $ 
 *
 * Digest Authentication Module
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of openser, a free SIP server.
 *
 * openser 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
 *
 * openser 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.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History:
 * --------
 * 2003-02-26 checks and group moved to separate modules (janakj)
 * 2003-03-10 New module interface (janakj)
 * 2003-03-16 flags export parameter added (janakj)
 * 2003-03-19 all mallocs/frees replaced w/ pkg_malloc/pkg_free (andrei)
 * 2003-04-28 rpid contributed by Juha Heinanen added (janakj) 
 * 2005-05-31 general avp specification added for rpid (bogdan)
 * 2006-03-01 pseudo variables support for domain name (bogdan)
 */


#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "../../sr_module.h"
#include "../../dprint.h"
#include "../../mem/mem.h"
#include "../../error.h"
#include "../../items.h"
#include "../../ut.h"
#include "auth_mod.h"
#include "challenge.h"
#include "rpid.h"
#include "api.h"

MODULE_VERSION

#define RAND_SECRET_LEN 32

#define DEF_RPID_PREFIX ""
#define DEF_RPID_SUFFIX ";party=calling;id-type=subscriber;screen=yes"
#define DEF_STRIP_REALM ""
#define DEF_RPID_AVP "s:rpid"


/*
 * Module destroy function prototype
 */
static void destroy(void);

/*
 * Module initialization function prototype
 */
static int mod_init(void);


static int challenge_fixup(void** param, int param_no);

/*  
 * Convert char* parameter to str* parameter   
 */
static int str_fixup(void** param, int param_no);


/*
 * Convert both parameters to str* representation
 */
static int rpid_fixup(void** param, int param_no);


/*
 * Pointer to reply function in stateless module
 */
int (*sl_reply)(struct sip_msg* _msg, char* _str1, char* _str2);


/*
 * Module parameter variables
 */
char* sec_param    = 0;   /* If the parameter was not used, the secret phrase will be auto-generated */
int   nonce_expire = 300; /* Nonce lifetime */

str secret;
char* sec_rand = 0;


/* Default Remote-Party-ID prefix */
str rpid_prefix = {DEF_RPID_PREFIX, sizeof(DEF_RPID_PREFIX) - 1};
/* Default Remote-Party-IDD suffix */
str rpid_suffix = {DEF_RPID_SUFFIX, sizeof(DEF_RPID_SUFFIX) - 1};
/* Prefix to strip from realm */
str realm_prefix = {DEF_STRIP_REALM, sizeof(DEF_STRIP_REALM) - 1};
/* definition of AVP containing rpid value */
char* rpid_avp_param = DEF_RPID_AVP;


/*
 * Exported functions 
 */
static cmd_export_t cmds[] = {
	{"www_challenge",       www_challenge,           2, challenge_fixup,
			REQUEST_ROUTE},
	{"proxy_challenge",     proxy_challenge,         2, challenge_fixup,
			REQUEST_ROUTE},
	{"consume_credentials", consume_credentials,     0, 0,
			REQUEST_ROUTE},
	{"is_rpid_user_e164",   is_rpid_user_e164,       0, 0,
			REQUEST_ROUTE},
	{"append_rpid_hf",      append_rpid_hf,          0, 0,
			REQUEST_ROUTE|BRANCH_ROUTE|FAILURE_ROUTE},
	{"append_rpid_hf",      append_rpid_hf_p,        2, rpid_fixup,
			REQUEST_ROUTE|BRANCH_ROUTE|FAILURE_ROUTE},
	{"bind_auth",           (cmd_function)bind_auth, 0, 0,
			0},
	{0, 0, 0, 0, 0}
};


/*
 * Exported parameters
 */
static param_export_t params[] = {
	{"secret",          STR_PARAM, &sec_param      },
	{"nonce_expire",    INT_PARAM, &nonce_expire   },
	{"rpid_prefix",     STR_PARAM, &rpid_prefix.s  },
	{"rpid_suffix",     STR_PARAM, &rpid_suffix.s  },
	{"realm_prefix",    STR_PARAM, &realm_prefix.s },
	{"rpid_avp",        STR_PARAM, &rpid_avp_param },
	{0, 0, 0}
};


/*
 * Module interface
 */
struct module_exports exports = {
	"auth", 
	cmds,
	params,
	0,          /* exported statistics */
	mod_init,   /* module initialization function */
	0,          /* response function */
	destroy,    /* destroy function */
	0           /* child initialization function */
};


/*
 * Secret parameter was not used so we generate
 * a random value here
 */
static inline int generate_random_secret(void)
{
	int i;

	sec_rand = (char*)pkg_malloc(RAND_SECRET_LEN);
	if (!sec_rand) {
		LOG(L_ERR, "ERROR:auth:generate_random_secret(): No pkg memory left\n");
		return -1;
	}

	srandom(time(0));

	for(i = 0; i < RAND_SECRET_LEN; i++) {
		sec_rand[i] = 32 + (int)(95.0 * rand() / (RAND_MAX + 1.0));
	}

	secret.s = sec_rand;
	secret.len = RAND_SECRET_LEN;

	/*DBG("Generated secret: '%.*s'\n", secret.len, secret.s); */

	return 0;
}


static int mod_init(void)
{
	LOG(L_INFO,"AUTH module - initializing\n");
	
	sl_reply = find_export("sl_send_reply", 2, 0);

	if (!sl_reply) {
		LOG(L_ERR, "ERROR:auth:mod_init: This module requires sl module\n");
		return -2;
	}

	/* If the parameter was not used */
	if (sec_param == 0) {
		/* Generate secret using random generator */
		if (generate_random_secret() < 0) {
			LOG(L_ERR,"ERROR:auth:mod_init: Error while generating "
				"random secret\n");
			return -3;
		}
	} else {
		/* Otherwise use the parameter's value */
		secret.s = sec_param;
		secret.len = strlen(secret.s);
	}

	if ( init_rpid_avp( rpid_avp_param)<0 ) {
		LOG(L_ERR,"ERROR:auth:mod_init: failed to process rpid AVPs\n");
		return -4;
	}

	rpid_prefix.len = strlen(rpid_prefix.s);
	rpid_suffix.len = strlen(rpid_suffix.s);
	realm_prefix.len = strlen(realm_prefix.s);

	return 0;
}



static void destroy(void)
{
	if (sec_rand) pkg_free(sec_rand);
}


static int challenge_fixup(void** param, int param_no)
{
	xl_elem_t *model;
	unsigned long qop;
	int err;
	char *s;
	
	if (param_no == 1) {
		s = (char*)*param;
		if (s==0 || s[0]==0) {
			model = 0;
		} else {
			if (xl_parse_format(s,&model,XL_DISABLE_COLORS)<0) {
				LOG(L_ERR, "ERROR:auth:challenge_fixup: xl_parse_format "
					"failed\n");
				return E_OUT_OF_MEM;
			}
		}
		*param = (void*)model;
	} else if (param_no == 2) {
		qop = str2s(*param, strlen(*param), &err);
		
		if (err == 0) {
			pkg_free(*param);
			*param=(void*)qop;
		} else {
			LOG(L_ERR, "challenge_fixup(): Bad number <%s>\n",
			    (char*)(*param));
			return E_UNSPEC;
		}
	}

	return 0;
}


/*
 * Convert char* parameter to str* parameter
 */
static int str_fixup(void** param, int param_no)
{
	str* s;
	
	if (param_no == 1) {
		s = (str*)pkg_malloc(sizeof(str));
		if (!s) {
			LOG(L_ERR, "str_fixup(): No memory left\n");
			return E_UNSPEC;
		}
		
		s->s = (char*)*param;
		s->len = strlen(s->s);
		*param = (void*)s;
	}
	
	return 0;
}


/*
 * Convert both parameters to str* representation
 */
static int rpid_fixup(void** param, int param_no)
{
	if (param_no == 1) {
		return str_fixup(param, 1);
	} else if (param_no == 2) {
		return str_fixup(param, 1);
	}
	return 0;
}