/*
 * $Id$
 *
 * Copyright (C) 2012 Smile Communications, jason.penton@smilecoms.com
 * Copyright (C) 2012 Smile Communications, richard.good@smilecoms.com
 * 
 * The initial version of this code was written by Dragos Vingarzan
 * (dragos(dot)vingarzan(at)fokus(dot)fraunhofer(dot)de and the
 * Fruanhofer Institute. It was and still is maintained in a separate
 * branch of the original SER. We are therefore migrating it to
 * Kamailio/SR and look forward to maintaining it from here on out.
 * 2011/2012 Smile Communications, Pty. Ltd.
 * ported/maintained/improved by 
 * Jason Penton (jason(dot)penton(at)smilecoms.com and
 * Richard Good (richard(dot)good(at)smilecoms.com) as part of an 
 * effort to add full IMS support to Kamailio/SR using a new and
 * improved architecture
 * 
 * NB: Alot of this code was originally part of OpenIMSCore,
 * FhG Fokus. 
 * Copyright (C) 2004-2006 FhG Fokus
 * Thanks for great work! This is an effort to 
 * break apart the various CSCF functions into logically separate
 * components. We hope this will drive wider use. We also feel
 * that in this way the architecture is more complete and thereby easier
 * to manage in the Kamailio/SR environment
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 */

#include "diameter.h"
#include "diameter_api.h"


#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>

#include "utils.h"
#include "globals.h"

#include "config.h"
#include "peermanager.h"
#include "diameter_epc_code_cmd.h"

extern dp_config *config;	/**< Configuration for this diameter peer */


/**
 * This function encodes a AAAMessage to its network representation (encoder).
 *  From a AAAMessage structure, a buffer to be send is built.
 * @param msg - the message to encode
 * @returns 1 on success, -1 on error
 * \note This function is taken from DISC http://developer.berlios.de/projects/disc/
 */
AAAReturnCode AAABuildMsgBuffer( AAAMessage *msg )
{
	unsigned char *p;
	AAA_AVP       *avp;

	/* first let's comput the length of the buffer */
	msg->buf.len = AAA_MSG_HDR_SIZE; /* AAA message header size */
	/* count and add the avps */
	for(avp=msg->avpList.head;avp;avp=avp->next) {
		msg->buf.len += AVP_HDR_SIZE(avp->flags)+ to_32x_len( avp->data.len );
	}

	LM_DBG("AAABuildMsgBuffer(): len=%d\n",msg->buf.len);
	/* allocate some memory */
	msg->buf.s = (char*)shm_malloc( msg->buf.len );
	if (!msg->buf.s) {
		LM_ERR("AAABuildMsgBuffer: no more free memory!\n");
		goto error;
	}
	memset(msg->buf.s, 0, msg->buf.len);

	/* fill in the buffer */
	p = (unsigned char*)msg->buf.s;
	/* DIAMETER HEADER */
	/* message length */
	((unsigned int*)p)[0] =htonl(msg->buf.len);
	/* Diameter Version */
	*p = 1;
	p += VER_SIZE + MESSAGE_LENGTH_SIZE;
	/* command code */
	((unsigned int*)p)[0] = htonl(msg->commandCode);
	/* flags */
	*p = (unsigned char)msg->flags;
	p += FLAGS_SIZE + COMMAND_CODE_SIZE;
	/* application-ID */
	((unsigned int*)p)[0] = htonl(msg->applicationId);
	p += APPLICATION_ID_SIZE;
	/* hop by hop id */
	((unsigned int*)p)[0] = htonl(msg->hopbyhopId);
	p += HOP_BY_HOP_IDENTIFIER_SIZE;
	/* end to end id */
	((unsigned int*)p)[0] = htonl(msg->endtoendId);
	p += END_TO_END_IDENTIFIER_SIZE;

	/* AVPS */
	for(avp=msg->avpList.head;avp;avp=avp->next) {
		/* AVP HEADER */
		/* avp code */
		set_4bytes(p,avp->code);
		p +=4;
		/* flags */
		(*p++) = (unsigned char)avp->flags;
		/* avp length */
		set_3bytes(p, (AVP_HDR_SIZE(avp->flags)+avp->data.len) );
		p += 3;
		/* vendor id */
		if ((avp->flags&0x80)!=0) {
			set_4bytes(p,avp->vendorId);
			p +=4;
		}
		/* data */
		memcpy( p, avp->data.s, avp->data.len);
		p += to_32x_len( avp->data.len );
	}

	if ((char*)p-msg->buf.s!=msg->buf.len) {
		LM_ERR("BUG: build_buf_from_msg: mismatch between len and buf!\n");
		shm_free( msg->buf.s );
		msg->buf.s = 0;
		msg->buf.len = 0;
		goto error;
	}

	return 1;
error:
	return -1;
}




/**
 *  Allocates a new AAAMessage.
 * @param commandCode - the command code for this message
 * @param applicationId - application id to be set
 * @param sessionId - session id to be set
 * @param request - if you want to create a response, put the request here. If you want a 
 * request, call with NULL
 * @returns the AAAMessage* or NULL on error
 * \note This function is taken from DISC http://developer.berlios.de/projects/disc/ 
 */
AAAMessage *AAANewMessage(
	AAACommandCode commandCode,
	AAAApplicationId applicationId,
	AAASession *session,
	AAAMessage *request)
{
	AAAMessage   *msg;
	AAA_AVP      *avp;
	AAA_AVP      *avp_t;
	str *sessionId=0;
#if 0
	unsigned int code;
#endif
	// str dest_host={"?",1};
	str dest_realm={"?",1};

	msg = 0;
	if (!session||!session->id.s) {
		if (request){
			/* copy old session id from AVP */
			if (request->sessionId) 
				sessionId = &(request->sessionId->data);
		}else{
			if (commandCode!=Code_DW)
				LM_DBG("AAANewMessage: param session received null and it's a request!!\n");
		}
	}else{
		sessionId = &(session->id);
	}

	/* allocated a new AAAMessage structure and set it to 0 */
	msg = (AAAMessage*)shm_malloc(sizeof(AAAMessage));
	if (!msg) {
		LM_ERR("AAANewMessage: no more free memory!!\n");
		goto error;
	}
	memset(msg,0,sizeof(AAAMessage));

	/* command code */
	msg->commandCode = commandCode;
	/* application ID */
	msg->applicationId = applicationId;

	/*add session ID */
	if (sessionId){
		avp = AAACreateAVP( 263, 0, 0, sessionId->s, sessionId->len,
			AVP_DUPLICATE_DATA);
		if ( !avp || AAAAddAVPToMessage(msg,avp,0)!=AAA_ERR_SUCCESS) {
			LM_ERR("AAANewMessage: cannot create/add Session-Id avp\n");
			if (avp) AAAFreeAVP( &avp );
			goto error;
		}
		msg->sessionId = avp;
	}

	/* add origin host AVP */
	/* changed by cristian to comply with rfc3588: 
	 * 6.3.  Origin-Host AVP
	 *
	 *    The Origin-Host AVP (AVP Code 264) is of type
	 *    DiameterIdentity... */
	avp = AAACreateAVP( 264, 0, 0, config->fqdn.s, config->fqdn.len,
		AVP_DUPLICATE_DATA);
	if (!avp||AAAAddAVPToMessage(msg,avp,msg->avpList.tail)!=AAA_ERR_SUCCESS) {
		LM_ERR("AAANewMessage: cannot create/add Origin-Host avp\n");
		if (avp) AAAFreeAVP( &avp );
		goto error;
	}
	msg->orig_host = avp;
	/* add origin realm AVP */
	avp = AAACreateAVP( 296, 0, 0, config->realm.s, config->realm.len,
		AVP_DUPLICATE_DATA);
	if (!avp||AAAAddAVPToMessage(msg,avp,msg->avpList.tail)!=AAA_ERR_SUCCESS) {
		LM_ERR("AAANewMessage: cannot create/add Origin-Realm avp\n");
		if (avp) AAAFreeAVP( &avp );
		goto error;
	}
	msg->orig_realm = avp;

	if (!request) {
		/* it's a new request -> set the flag */
		msg->flags = 0x80;
	} else {
		/* link the incoming peer to the answer */
		msg->in_peer = request->in_peer;
		/* set the P flag as in request */
		msg->flags |= request->flags&0x40;
		/**/
		msg->endtoendId = request->endtoendId;
		msg->hopbyhopId = request->hopbyhopId;

		
		//TODO: aon:move this information in the AAASession structure, do not add these fields for
		
	    if (msg->commandCode==Code_CE||msg->commandCode==Code_DP||msg->commandCode==Code_DW ||
			    msg->commandCode==Diameter_CCR || msg->commandCode==Diameter_RAR){
	    	// Don't add Destination Host/Realm because some stacks are way to picky and will just refuse it
	    }else{

			/* Mirror the old originhost/realm to destinationhost/realm*/
			//avp = AAAFindMatchingAVP(request,0,AVP_Origin_Host,0,0);
			//if (avp) dest_host = avp->data;
			/* add destination host and destination realm */
			//avp = AAACreateAVP(AVP_Destination_Host,AAA_AVP_FLAG_MANDATORY,0,
			//	dest_host.s,dest_host.len,AVP_DUPLICATE_DATA);
			//if (!avp) {
		//		LM_ERR("ERR:AAANewMessage: Failed creating Destination Host avp\n");
		//		goto error;
		//	}
		//	if (AAAAddAVPToMessage(msg,avp,msg->avpList.tail)!=AAA_ERR_SUCCESS) {
		//		LM_ERR("ERR:AAANewMessage: Failed adding Destination Host avp to message\n");
		//		AAAFreeAVP(&avp);
		//		goto error;
		//	}
	
			avp = AAAFindMatchingAVP(request,0,AVP_Origin_Realm,0,0);
			if (avp) dest_realm = avp->data;
			avp = AAACreateAVP(AVP_Destination_Realm,AAA_AVP_FLAG_MANDATORY,0,
				dest_realm.s,dest_realm.len,AVP_DUPLICATE_DATA);
			if (!avp) {
				LM_ERR("ERR:AAANewMessage: Failed creating Destination Realm avp\n");
				goto error;
			}
			if (AAAAddAVPToMessage(msg,avp,msg->avpList.tail)!=AAA_ERR_SUCCESS) {
				LM_ERR("ERR:AAANewMessage: Failed adding Destination Realm avp to message\n");
				AAAFreeAVP(&avp);
				goto error;
			}
	    }

		msg->res_code=0;
		/* mirror all the proxy-info avp in the same order */
		avp_t = request->avpList.head;
		while ( (avp_t=AAAFindMatchingAVP
		(request,avp_t,284,0,AAA_FORWARD_SEARCH))!=0 ) {
			if ( (avp=AAACloneAVP(avp_t,1))==0 || AAAAddAVPToMessage( msg, avp,
			msg->avpList.tail)!=AAA_ERR_SUCCESS )
				goto error;
		}
	}

	return msg;
error:
	LM_ERR("AAANewMessage: failed to create a new AAA message!\n");
	AAAFreeMessage(&msg);
	return 0;
}

/**
 * Create a Diameter Request.
 * @param app_id - application id to be set
 * @param command_code - the command code for this message
 * @param flags - flags to be set
 * @param sessId - session id to be set
 * @returns the AAAMessage* or NULL on error
 */
AAAMessage *AAACreateRequest(AAAApplicationId app_id,
							AAACommandCode command_code,
							AAAMsgFlag flags,
							AAASession *session)
{
	AAAMessage *msg;
	AAA_AVP      *avp;

	msg = AAANewMessage(command_code,app_id,session,0);
	if (!msg) return 0;
	msg->hopbyhopId = next_hopbyhop();
	msg->endtoendId = next_endtoend();
	msg->flags |= flags;	

	if(session){
		/* add destination host and destination realm */
		/*if(session->dest_host.s){//TODO: check spec about removing this across the board (jason)
			avp = AAACreateAVP(AVP_Destination_Host,AAA_AVP_FLAG_MANDATORY,0,
				session->dest_host.s,session->dest_host.len,AVP_DUPLICATE_DATA);
			if (!avp) {
				LM_ERR("ERR:AAACreateRequest: Failed creating Destination Host avp\n");
				goto error;
			}
			if (AAAAddAVPToMessage(msg,avp,msg->avpList.tail)!=AAA_ERR_SUCCESS) {
				LM_ERR("ERR:AAACreateRequest: Failed adding Destination Host avp to message\n");
				AAAFreeAVP(&avp);
				goto error;
			}
		}*/

		if(session->dest_realm.s){
			avp = AAACreateAVP(AVP_Destination_Realm,AAA_AVP_FLAG_MANDATORY,0,
				session->dest_realm.s,session->dest_realm.len,AVP_DUPLICATE_DATA);
			if (!avp) {
				LM_ERR("ERR:AAACreateRequest: Failed creating Destination Realm avp\n");
				goto error;
			}
			if (AAAAddAVPToMessage(msg,avp,msg->avpList.tail)!=AAA_ERR_SUCCESS) {
				LM_ERR("ERR:AAACreateRequest: Failed adding Destination Realm avp to message\n");
				AAAFreeAVP(&avp);
				goto error;
			}		
		}
	}

	return msg;
error:
	AAAFreeMessage(&msg);
	return NULL;
}

/**
 * Create a Diameter Response to a given Request. 
 * @param request - the request that this response is for
 * @returns the AAAMessage* or NULL on error
 */
AAAMessage *AAACreateResponse(AAAMessage *request)
{
	AAAMessage *msg;
	msg = AAANewMessage(request->commandCode,request->applicationId,0,request);
		
	return msg;
}


/**
 *  Frees a AVP List and all the members
 * @param avpList - list to be freed
 * @returns AAA_ERR_SUCCESS 
 */
AAAReturnCode  AAAFreeAVPList(AAA_AVP_LIST *avpList)
{
	AAA_AVP *avp_t;
	AAA_AVP *avp;
	/* free the avp list */
	avp = avpList->head;
	while (avp) {
		avp_t = avp;
		avp = avp->next;
		/*free the avp*/
		AAAFreeAVP(&avp_t);
	}
	avpList->head = 0;
	avpList->tail = 0;
	return AAA_ERR_SUCCESS;
}

/**
 *  Frees completely a message allocated through AAANewMessage()
 * @param msg - pointer to the pointer containing the message.
 * @returns AAA_ERR_SUCCESS 
 */
AAAReturnCode  AAAFreeMessage(AAAMessage **msg)
{
	LM_DBG("AAAFreeMessage: Freeing message (%p) %d\n",*msg,(*msg)->commandCode);
	/* param check */
	if (!msg || !(*msg))
		goto done;

	/* free the avp list */
	AAAFreeAVPList(&((*msg)->avpList));

	/* free the buffer (if any) */
	if ( (*msg)->buf.s )
		shm_free( (*msg)->buf.s );

	/* free the AAA msg */
	shm_free(*msg);
	*msg = 0;

done:
	return AAA_ERR_SUCCESS;
}

/**
 *  Sets the proper result_code into the Result-Code AVP; ths avp must already
 * exists into the reply messge.
 * @param message - the message to set the Result-Code to
 * @param resultCode - code to set as result 
 * \note This function is taken from DISC http://developer.berlios.de/projects/disc/ 
 */
AAAResultCode  AAASetMessageResultCode(
	AAAMessage *message,
	AAAResultCode resultCode)
{
	if ( !is_req(message) && message->res_code) {
		*((unsigned int*)(message->res_code->data.s)) = htonl(resultCode);
		return AAA_ERR_SUCCESS;
	}
	return AAA_ERR_FAILURE;
}



/**
 *  This function convert message from the network format to the AAAMessage structure (decoder).
 * @param source - the source char buffer
 * @param sourceLen - the length of the input buffer
 * @param attach_buf - whether to attach the input buffer to the message
 * @returns the AAAMessage* or NULL on error
 * \note This function is taken from DISC http://developer.berlios.de/projects/disc/ 
 */
AAAMessage* AAATranslateMessage( unsigned char* source, unsigned int sourceLen,
															int attach_buf)
{
	unsigned char *ptr;
	AAAMessage    *msg;
	unsigned char version;
	unsigned int  msg_len;
	AAA_AVP       *avp;
	unsigned int  avp_code;
	unsigned char avp_flags;
	unsigned int  avp_len;
	unsigned int  avp_vendorID;
	unsigned int  avp_data_len;

	/* check the params */
	if( !source || !sourceLen || sourceLen<AAA_MSG_HDR_SIZE) {
		LM_ERR("AAATranslateMessage: invalid buffered received!\n");
		goto error;
	}

	/* inits */
	msg = 0;
	avp = 0;
	ptr = source;

	/* alloc a new message structure */
	msg = (AAAMessage*)shm_malloc(sizeof(AAAMessage));
	if (!msg) {
		LM_ERR("AAATranslateMessage: no more free memory!!\n");
		goto error;
	}
	memset(msg,0,sizeof(AAAMessage));

	/* get the version */
	version = (unsigned char)*ptr;
	ptr += VER_SIZE;
	if (version!=1) {
		LM_ERR("AAATranslateMessage: invalid version [%d]in "
			"AAA msg\n",version);
		goto error;
	}

	/* message length */
	msg_len = get_3bytes( ptr );
	ptr += MESSAGE_LENGTH_SIZE;
	if (msg_len>sourceLen) {
		LM_ERR("AAATranslateMessage: AAA message len [%d] bigger then"
			" buffer len [%d]\n",msg_len,sourceLen);
		goto error;
	}

	/* command flags */
	msg->flags = *ptr;
	ptr += FLAGS_SIZE;

	/* command code */
	msg->commandCode = get_3bytes( ptr );
	ptr += COMMAND_CODE_SIZE;

	/* application-Id */
	msg->applicationId = get_4bytes( ptr );
	ptr += APPLICATION_ID_SIZE;

	/* Hop-by-Hop-Id */
	msg->hopbyhopId = ntohl(*((unsigned int*)ptr));
	ptr += HOP_BY_HOP_IDENTIFIER_SIZE;

	/* End-to-End-Id */
	msg->endtoendId = ntohl(*((unsigned int*)ptr));
	ptr += END_TO_END_IDENTIFIER_SIZE;

	/* start decoding the AVPS */
	while (ptr < source+msg_len) {
		if (ptr+AVP_HDR_SIZE(0x80)>source+msg_len){
			LM_ERR("AAATranslateMessage: source buffer to short!! "
				"Cannot read the whole AVP header!\n");
			goto error;
		}
		/* avp code */
		avp_code = get_4bytes( ptr );
		ptr += AVP_CODE_SIZE;
		/* avp flags */
		avp_flags = (unsigned char)*ptr;
		ptr += AVP_FLAGS_SIZE;
		/* avp length */
		avp_len = get_3bytes( ptr );
		ptr += AVP_LENGTH_SIZE;
		if (avp_len<1) {
			LM_ERR("AAATranslateMessage: invalid AVP len [%d]\n",
				avp_len);
			goto error;
		}
		/* avp vendor-ID */
		avp_vendorID = 0;
		if (avp_flags&AAA_AVP_FLAG_VENDOR_SPECIFIC) {
			avp_vendorID = get_4bytes( ptr );
			ptr += AVP_VENDOR_ID_SIZE;
		}
		/* data length */
		avp_data_len = avp_len-AVP_HDR_SIZE(avp_flags);
		/*check the data length */
		if ( source+msg_len<ptr+avp_data_len) {
			LM_ERR("AAATranslateMessage: source buffer to short!! "
				"Cannot read a whole data for AVP!\n");
			goto error;
		}

		/* create the AVP */
		avp = AAACreateAVP( avp_code, avp_flags, avp_vendorID, (char*) ptr,
			avp_data_len, AVP_DONT_FREE_DATA);
		if (!avp)
			goto error;

		/* link the avp into aaa message to the end */
		AAAAddAVPToMessage( msg, avp, msg->avpList.tail);

		ptr += to_32x_len( avp_data_len );
	}

	/* link the buffer to the message */
	if (attach_buf) {
		msg->buf.s = (char*) source;
		msg->buf.len = msg_len;
	}

	msg->sessionId = AAAFindMatchingAVP(msg,0,AVP_Session_Id,0,0);

	//AAAPrintMessage( msg );
	return  msg;
error:
	LM_ERR("AAATranslateMessage: message conversion droped!!\n");
	AAAFreeMessage(&msg);
	return 0;
}



/**
 *  print as debug all info contained by an aaa message + AVPs
 * @param msg - the AAAMessage to print
 * \note This function is taken from DISC http://developer.berlios.de/projects/disc/ 
 */
void AAAPrintMessage( AAAMessage *msg)
{
	char    buf[1024];
	AAA_AVP *avp;

	/* print msg info */
	LM_DBG("AAA_MESSAGE - %p\n",msg);
	LM_DBG("\tCode = %u\n",msg->commandCode);
	LM_DBG("\tFlags = %x\n",msg->flags);

	/*print the AVPs */
	avp = msg->avpList.head;
	while (avp) {
		AAAConvertAVPToString(avp,buf,1024);
		LM_DBG("\n%s\n",buf);
		avp=avp->next;
	}
}