/*
 * 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
 * Fraunhofer FOKUS 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: A lot 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.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * 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 <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>

#include "peerstatemachine.h"
#include "diameter_api.h"
#include "diameter_ims.h"

#include "utils.h"
#include "receiver.h"
#include "peermanager.h"
#include "config.h"
#include "worker.h"
#include "authstatemachine.h"
#include "acctstatemachine.h"

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

/** Strings for the peer states */
char *dp_states[] = {"Closed", "Wait_Conn_Ack", "Wait_I_CEA",
		"Wait_Conn_Ack_Elect", "Wait_Returns", "R_Open", "I_Open", "Closing"};
/** Strings for the peer events */
char *dp_events[] = {"Start", "Stop", "Timeout", "Win_Election", "R_Conn_CER",
		"I_Rcv_Conn_Ack", "I_Rcv_Conn_NAck", "I_Rcv_CER", "I_Rcv_CEA",
		"R_Rcv_CER", "R_Rcv_CEA", "I_Rcv_Non_CEA", "I_Rcv_DPR", "I_Rcv_DPA",
		"R_Rcv_DPR", "R_Rcv_DPA", "I_Rcv_DWR", "I_Rcv_DWA", "R_Rcv_DWR",
		"R_Rcv_DWA", "Send_Message", "I_Rcv_Message", "R_Rcv_Message",
		"I_Peer_Disc", "R_Peer_Disc"};

/**
 * Diameter base protocol state-machine processing.
 * This function get's called for every event. It updates the states and can trigger
 * other events.
 * @param p - the peer for which the event happened
 * @param event - the event that happened
 * @param msg - if a Diameter message was received this is it, or NULL if not
 * @param peer_locked - if the peer lock is already aquired
 * @param sock - socket that this event happened on, or NULL if unrelated
 * @returns 1 on success, 0 on error. Also the peer states are updated
 */
int sm_process(
		peer *p, peer_event_t event, AAAMessage *msg, int peer_locked, int sock)
{
	int result_code;
	peer_event_t next_event;
	int msg_received = 0;

	if(!peer_locked)
		lock_get(p->lock);
	LM_DBG("Peer %.*s State %s Event %s\n", p->fqdn.len, p->fqdn.s,
			dp_states[p->state], dp_events[event - 101]);

	switch(p->state) {
		case Closed:
			switch(event) {
				case Start:
					p->state = Wait_Conn_Ack;
					next_event = I_Snd_Conn_Req(p);
					if(next_event == I_Rcv_Conn_NAck)
						sm_process(p, next_event, 0, 1, p->I_sock);
					else {
						/* wait for fd to be transmitted to the respective receiver,
						 * in order to get a send pipe opened */
					}
					break;
				case R_Conn_CER:
					R_Accept(p, sock);
					result_code = Process_CER(p, msg);
					Snd_CEA(p, msg, result_code, p->R_sock);
					msg = 0;
					if(result_code >= 2000 && result_code < 3000)
						p->state = R_Open;
					else {
						R_Disc(p);
						p->state = Closed;
					}
					log_peer_list();
					break;
				case Stop:
					/* just ignore this state */
					p->state = Closed;
					break;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;
		case Wait_Conn_Ack:
			switch(event) {
				case I_Rcv_Conn_Ack:
					p->state = Wait_I_CEA;
					I_Snd_CER(p);
					if(p->state == Closed)
						sm_process(p, Start, 0, 1, 0);
					break;
				case I_Rcv_Conn_NAck:
					Cleanup(p, p->I_sock);
					p->state = Closed;
					break;
				case R_Conn_CER:
					if(p->r_cer)
						AAAFreeMessage(&(p->r_cer));
					R_Accept(p, sock);
					result_code = Process_CER(p, msg);
					if(result_code >= 2000 && result_code < 3000) {
						p->state = Wait_Conn_Ack_Elect;
						p->r_cer = msg;
					} else {
						p->state = Closed;
						AAAFreeMessage(&msg);
						R_Disc(p);
						I_Disc(p);
					}
					break;
				case Timeout:
					Error(p, p->I_sock);
					p->state = Closed;
					LM_ERR("in state %s timeout event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;

		case Wait_I_CEA:
			switch(event) {
				case I_Rcv_CEA:
					result_code = Process_CEA(p, msg);
					if(result_code >= 2000 && result_code < 3000)
						p->state = I_Open;
					else {
						Cleanup(p, p->I_sock);
						p->state = Closed;
					}
					log_peer_list();
					break;
				case R_Conn_CER:
					if(p->r_cer)
						AAAFreeMessage(&(p->r_cer));
					R_Accept(p, sock);
					result_code = Process_CER(p, msg);
					if(result_code >= 2000 && result_code < 3000) {
						p->state = Wait_Returns;
						if(Elect(p, msg)) {
							// won the election = > I_Disc(), R_Send_CEA()
							LM_INFO("Wait_I_CEA Win Elect \n");
							sm_process(p, Win_Election, msg, 1, sock);
						} else {
							// lost the election => wait for I_Recv_CEA, then R_Disc()
							LM_INFO("Wait_I_CEA Lose Elect \n");
							p->r_cer = msg;
							sm_process(p, I_Peer_Disc, 0, 1, p->I_sock);
						}
					} else {
						Snd_CEA(p, msg, result_code, p->R_sock);
						R_Disc(p);
						I_Disc(p);
						p->state = Closed;
						break;
					}
					break;
				case I_Peer_Disc:
					I_Disc(p);
					p->state = Closed;
					break;
				case I_Rcv_Non_CEA:
					Error(p, p->I_sock);
					p->state = Closed;
					break;
				case Timeout:
					Error(p, p->I_sock);
					p->state = Closed;
					break;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;

		case Wait_Conn_Ack_Elect:
			switch(event) {
				case I_Rcv_Conn_Ack:
					I_Snd_CER(p);
					if(p->r_cer) {
						p->state = Wait_Returns;
						if(Elect(p, p->r_cer)) {
							// won the election = > I_Disc(), R_Send_CEA()
							LM_INFO("Wait_Conn_Ack_Elect Win "
									"Elect \n");
							sm_process(p, Win_Election, p->r_cer, 1, sock);
							p->r_cer = 0;
						} else {
							// lost the election => wait for I_Recv_CEA, then R_Disc()
							LM_INFO("Wait_Conn_Ack_Elect Lose "
									"Elect \n");
							AAAFreeMessage(&p->r_cer);
						}
					} else {
						LM_ERR("Wait_Conn_Ack_Elect, "
							   "I_Rcv_Conn_Ack, No R-CER ! \n");
						p->state = Wait_I_CEA;
					}
					break;
				case I_Rcv_Conn_NAck:
					Cleanup(p, p->I_sock);
					if(p->r_cer) {
						result_code = Process_CER(p, p->r_cer);
						Snd_CEA(p, p->r_cer, result_code, p->R_sock);
						p->r_cer = 0;
						if(result_code >= 2000 && result_code < 3000)
							p->state = R_Open;
						else {
							R_Disc(p);
							p->state = Closed;
							//	p->state = R_Open; /* Or maybe I should disconnect it?*/
						}
					} else {
						LM_ERR("Wait_Conn_Ack_Elect, "
							   "I_Rcv_Conn_NAck No R-CER ! \n");
					}
					break;
				case R_Peer_Disc:
					R_Disc(p);
					p->state = Wait_Conn_Ack;
					break;
				case R_Conn_CER:
					R_Reject(p, sock);
					AAAFreeMessage(&msg);
					p->state = Wait_Conn_Ack_Elect;
					break;
				case Timeout:
					if(p->I_sock >= 0)
						Error(p, p->I_sock);
					if(p->R_sock >= 0)
						Error(p, p->R_sock);
					p->state = Closed;
					break;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;

		case Wait_Returns:
			switch(event) {
				case Win_Election:
					/* this is the Win Election -> I is dropped, R is kept */
					LM_INFO("Wait_Returns Win Elect \n");
					I_Disc(p);
					result_code = Process_CER(p, msg);
					Snd_CEA(p, msg, result_code, p->R_sock);
					if(result_code >= 2000 && result_code < 3000) {
						p->state = R_Open;
					} else {
						R_Disc(p);
						p->state = Closed;
					}
					break;
				case I_Peer_Disc:
					I_Disc(p);
					if(p->r_cer) {
						result_code = Process_CER(p, p->r_cer);
						Snd_CEA(p, p->r_cer, result_code, p->R_sock);
						p->r_cer = 0;
						if(result_code >= 2000 && result_code < 3000) {
							p->state = R_Open;
						} else {
							R_Disc(p);
							p->state = Closed;
						}
					} else {
						LM_ERR("Wait_Returns, I_Peer_Disc No "
							   "R-CER ! \n");
					}
					break;
				case I_Rcv_CEA:
					/* this is the Lost Election -> I is kept, R dropped */
					LM_INFO("Wait_Returns Lost Elect \n");
					R_Disc(p);
					result_code = Process_CEA(p, msg);
					if(result_code >= 2000 && result_code < 3000)
						p->state = I_Open;
					else {
						Cleanup(p, p->I_sock);
						p->state = Closed;
					}
					break;
				case R_Peer_Disc:
					R_Disc(p);
					p->state = Wait_I_CEA;
					break;
				case R_Conn_CER:
					R_Reject(p, p->R_sock);
					AAAFreeMessage(&msg);
					p->state = Wait_Returns;
					break;
				case Timeout:
					if(p->I_sock >= 0)
						Error(p, p->I_sock);
					if(p->R_sock >= 0)
						Error(p, p->R_sock);
					p->state = Closed;
					LM_ERR("in state %s timeout event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;
		case R_Open:
			switch(event) {
				case Send_Message:
					Snd_Message(p, msg);
					p->state = R_Open;
					break;
				case R_Rcv_Message:
					// delayed processing until out of the critical zone
					//Rcv_Process(p,msg);
					msg_received = 1;
					p->state = R_Open;
					break;
				case R_Rcv_DWR:
					result_code = Process_DWR(p, msg);
					Snd_DWA(p, msg, result_code, p->R_sock);
					p->state = R_Open;
					break;
				case R_Rcv_DWA:
					Process_DWA(p, msg);
					p->state = R_Open;
					break;
				case R_Conn_CER:
					R_Reject(p, sock);
					AAAFreeMessage(&msg);
					p->state = R_Open;
					break;
				case Stop:
					Snd_DPR(p);
					p->state = Closing;
					break;
				case R_Rcv_DPR:
					Snd_DPA(p, msg, AAA_SUCCESS, p->R_sock);
					R_Disc(p);
					p->state = Closed;
					log_peer_list();
					break;
				case R_Peer_Disc:
					R_Disc(p);
					p->state = Closed;
					log_peer_list();
					break;
				case R_Rcv_CER:
					result_code = Process_CER(p, msg);
					Snd_CEA(p, msg, result_code, p->R_sock);
					if(result_code >= 2000 && result_code < 3000)
						p->state = R_Open;
					else {
						/*R_Disc(p);p.state = Closed;*/
						p->state = R_Open; /* Or maybe I should disconnect it?*/
					}
					break;
				case R_Rcv_CEA:
					result_code = Process_CEA(p, msg);
					if(result_code >= 2000 && result_code < 3000)
						p->state = R_Open;
					else {
						/*R_Disc(p);p.state = Closed;*/
						p->state = R_Open; /* Or maybe I should disconnect it?*/
					}
					log_peer_list();
					break;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;
		case I_Open:
			switch(event) {
				case Send_Message:
					Snd_Message(p, msg);
					p->state = I_Open;
					break;
				case I_Rcv_Message:
					// delayed processing until out of the critical zone
					//Rcv_Process(p,msg);
					msg_received = 1;
					p->state = I_Open;
					break;
				case I_Rcv_DWR:
					result_code = Process_DWR(p, msg);
					Snd_DWA(p, msg, result_code, p->I_sock);
					p->state = I_Open;
					break;
				case I_Rcv_DWA:
					Process_DWA(p, msg);
					p->state = I_Open;
					break;
				case R_Conn_CER:
					R_Reject(p, sock);
					AAAFreeMessage(&msg);
					p->state = I_Open;
					break;
				case Stop:
					Snd_DPR(p);
					p->state = Closing;
					break;
				case I_Rcv_DPR:
					Snd_DPA(p, msg, 2001, p->I_sock);
					I_Disc(p);
					p->state = Closed;
					log_peer_list();
					break;
				case I_Peer_Disc:
					I_Disc(p);
					p->state = Closed;
					log_peer_list();
					break;
				case I_Rcv_CER:
					result_code = Process_CER(p, msg);
					Snd_CEA(p, msg, result_code, p->I_sock);
					if(result_code >= 2000 && result_code < 3000)
						p->state = I_Open;
					else {
						/*I_Disc(p);p.state = Closed;*/
						p->state = I_Open; /* Or maybe I should disconnect it?*/
					}
					break;
				case I_Rcv_CEA:
					result_code = Process_CEA(p, msg);
					if(result_code >= 2000 && result_code < 3000)
						p->state = I_Open;
					else {
						/*I_Disc(p);p.state = Closed;*/
						p->state = I_Open; /* Or maybe I should disconnect it?*/
					}
					break;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;
		case Closing:
			switch(event) {
				case I_Rcv_DPA:
					I_Disc(p);
					p->state = Closed;
					break;
				case R_Rcv_DPA:
					R_Disc(p);
					p->state = Closed;
					break;
				case Timeout:
					if(p->I_sock >= 0)
						Error(p, p->I_sock);
					if(p->R_sock >= 0)
						Error(p, p->R_sock);
					p->state = Closed;
					break;
				case I_Peer_Disc:
					I_Disc(p);
					p->state = Closed;
					break;
				case R_Peer_Disc:
					R_Disc(p);
					p->state = Closed;
					break;
				default:
					LM_ERR("In state %s invalid event %s\n",
							dp_states[p->state], dp_events[event - 101]);
					goto error;
			}
			break;
	}
	if(!peer_locked)
		lock_release(p->lock);

	if(msg_received)
		Rcv_Process(p, msg);

	return 1;
error:
	if(!peer_locked)
		lock_release(p->lock);
	return 0;
}

/**
 * Initiator - Send Connection Request.
 * Tries to connect to the remote peer's socket. If the connection is refused, the new
 * state is I_Rcv_Conn_NAck, else I_Rcv_Conn_Ack.
 * \note Must be called with a lock on the peer.
 * @param p - peer to send to
 * @returns the new state for the peer
 */
peer_event_t I_Snd_Conn_Req(peer *p)
{
	LM_INFO("Peer %.*s \n", p->fqdn.len, p->fqdn.s);

	if(p->I_sock > 0)
		close(p->I_sock);
	p->I_sock = -1;
	p->I_sock = peer_connect(p);
	if(p->I_sock < 0) {
		return I_Rcv_Conn_NAck;
	}

	return I_Rcv_Conn_Ack;
}

/**
 * Cleans a socket by closing it and removing the reference
 * \note Must be called with a lock on the peer.
 * @param p - the peer
 * @param sock - socket to close
 */
void Cleanup(peer *p, int sock)
{
	if(sock < 0)
		return;
	close(sock);
	if(p->I_sock == sock)
		p->I_sock = -1;
	if(p->R_sock == sock)
		p->R_sock = -1;
}

/**
 * Error action for a peer, triggers a Cleanup action.
 * \note Must be called with a lock on the peer.
 * @param p - the peer
 * @param sock - socket to close
 */
void Error(peer *p, int sock)
{
	Cleanup(p, sock);
}

/**
 * Adds the Applications to a Capability Exchange message.
 * \note Must be called with a lock on the peer.
 * @param msg - the message to add to (request/answer)
 * @param p - the peer to add applications from
 */
static inline void Snd_CE_add_applications(AAAMessage *msg, peer *p)
{
	int i;
	app_config *app;
	char x[4];
	AAA_AVP *avp1, *avp2;
	AAA_AVP_LIST list;
	str group;
	list.head = 0;
	list.tail = 0;

	for(i = 0; i < config->applications_cnt; i++) {
		app = config->applications + i;
		if(app->vendor == 0) {
			set_4bytes(x, app->id);
			AAACreateAndAddAVPToMessage(msg,
					(app->type == DP_AUTHORIZATION ? AVP_Auth_Application_Id
												   : AVP_Acct_Application_Id),
					AAA_AVP_FLAG_MANDATORY, 0, x, 4);
		} else {
			set_4bytes(x, app->vendor);
			avp1 = AAACreateAVP(AVP_Vendor_Id, AAA_AVP_FLAG_MANDATORY, 0, x, 4,
					AVP_DUPLICATE_DATA);
			AAAAddAVPToList(&list, avp1);

			set_4bytes(x, app->id);
			avp2 = AAACreateAVP(
					(app->type == DP_AUTHORIZATION ? AVP_Auth_Application_Id
												   : AVP_Acct_Application_Id),
					AAA_AVP_FLAG_MANDATORY, 0, x, 4, AVP_DUPLICATE_DATA);
			AAAAddAVPToList(&list, avp2);

			group = AAAGroupAVPS(list);
			AAAFreeAVPList(&list);

			AAACreateAndAddAVPToMessage(msg, AVP_Vendor_Specific_Application_Id,
					AAA_AVP_FLAG_MANDATORY, 0, group.s, group.len);
			shm_free(group.s);
		}
	}
	for(i = 0; i < config->supported_vendors_cnt; i++) {
		set_4bytes(x, config->supported_vendors[i]);
		AAACreateAndAddAVPToMessage(
				msg, AVP_Supported_Vendor_Id, AAA_AVP_FLAG_MANDATORY, 0, x, 4);
	}
}

/**
 * Send a Capability Exchange Request.
 * \note Must be called with a lock on the peer.
 * @param p - the peer to send to
 */
void I_Snd_CER(peer *p)
{
	AAAMessage *cer = 0;
	//	AAA_AVP *avp;
	unsigned long ip;
	union
	{
		struct sockaddr addr;
		struct sockaddr_in in;
		struct sockaddr_in6 in6;
	} addr_u;
	socklen_t addrlen;
	char x[18];
	int ret = 0;

	cer = AAANewMessage(Code_CE, 0, 0, 0);
	if(!cer)
		return;
	cer->hopbyhopId = next_hopbyhop();
	cer->endtoendId = next_endtoend();
	addrlen = sizeof(addr_u);
	if((ret = getsockname(p->I_sock, &(addr_u.addr), &addrlen)) == -1) {
		LM_ERR("Error on finding local host address > %s\n", strerror(errno));
		Cleanup(p, p->I_sock);
		p->state = Closed;
		AAAFreeMessage(&cer);
		return;
	}

	if(ret != -1) {
		switch(addr_u.addr.sa_family) {
			case AF_INET:
				set_2bytes(x, 1);
				ip = htonl(addr_u.in.sin_addr.s_addr);
				set_4bytes(x + 2, ip);
				AAACreateAndAddAVPToMessage(cer, AVP_Host_IP_Address,
						AAA_AVP_FLAG_MANDATORY, 0, x, 6);
				break;
			case AF_INET6:
				set_2bytes(x, 2);
				memcpy(x + 2, addr_u.in6.sin6_addr.s6_addr, 16);
				AAACreateAndAddAVPToMessage(cer, AVP_Host_IP_Address,
						AAA_AVP_FLAG_MANDATORY, 0, x, 18);
				break;
			default:
				LM_ERR("unknown address type with family %d\n",
						addr_u.addr.sa_family);
		}
	}

	set_4bytes(x, config->vendor_id);
	AAACreateAndAddAVPToMessage(
			cer, AVP_Vendor_Id, AAA_AVP_FLAG_MANDATORY, 0, x, 4);

	AAACreateAndAddAVPToMessage(cer, AVP_Product_Name, AAA_AVP_FLAG_MANDATORY,
			0, config->product_name.s, config->product_name.len);

	Snd_CE_add_applications(cer, p);
	//	peer_send(p,p->I_sock,cer,1);
	peer_send_msg(p, cer);
}


void add_peer_application(peer *p, int id, int vendor, app_type type)
{
	int i;
	if(!p->applications)
		return;
	for(i = 0; i < p->applications_cnt; i++)
		if(p->applications[i].id == id && p->applications[i].vendor == vendor
				&& p->applications[i].type == type)
			return;

	if(p->applications_cnt >= p->applications_max) {
		LM_ERR("Too many applications for this peer (max %i), not adding "
			   "Application %i:%i.\n",
				p->applications_max, id, vendor);
		return;
	}

	p->applications[p->applications_cnt].id = id;
	p->applications[p->applications_cnt].vendor = vendor;
	p->applications[p->applications_cnt].type = type;
	LM_DBG("Application number %i with id %d and vendor %d added, maximum %i\n",
			p->applications_cnt, id, vendor, p->applications_max);
	p->applications_cnt++;
}

int count_Supported_Vendor_Id_AVPS(AAAMessage *msg)
{
	AAA_AVP *avp_vendor;
	int avp_vendor_cnt;

	avp_vendor = AAAFindMatchingAVP(msg, 0, AVP_Supported_Vendor_Id, 0, 0);
	avp_vendor_cnt = 0;
	while(avp_vendor) {
		avp_vendor_cnt++;
		if(!avp_vendor->next)
			break;
		avp_vendor = AAAFindMatchingAVP(
				msg, avp_vendor->next, AVP_Supported_Vendor_Id, 0, 0);
	}
	LM_DBG("Found %i Supported_Vendor AVPS\n", avp_vendor_cnt);
	return avp_vendor_cnt;
}

void save_peer_applications(peer *p, AAAMessage *msg)
{
	int total_cnt = 0;
	int supported_vendor_id_avp_cnt = 0;
	AAA_AVP *avp, *avp_vendor, *avp2;
	AAA_AVP_LIST group;
	int id, vendor;

	if(p->applications) {
		shm_free(p->applications);
		p->applications = 0;
		p->applications_cnt = 0;
	}

	supported_vendor_id_avp_cnt = count_Supported_Vendor_Id_AVPS(msg);

	if(supported_vendor_id_avp_cnt == 0) {
		LM_INFO("No Supported-Vendor-Id AVP found, assuming compability with "
				"%d vendor(s) from our CER msg\n",
				config->supported_vendors_cnt);
		supported_vendor_id_avp_cnt = 1;
	}

	for(avp = msg->avpList.head; avp; avp = avp->next)

		switch(avp->code) {
			case AVP_Auth_Application_Id:
				total_cnt += supported_vendor_id_avp_cnt;
				break;
			case AVP_Acct_Application_Id:
				total_cnt += supported_vendor_id_avp_cnt;
				break;
			case AVP_Vendor_Specific_Application_Id:
				total_cnt += 6; /* wasteful, but let's skip decoding */
				break;
		}
	LM_DBG("Total count of applications is %d\n", total_cnt);

	p->applications_cnt = 0;
	p->applications = shm_malloc(sizeof(app_config) * total_cnt);
	p->applications_max = total_cnt;
	if(!p->applications) {
		LM_ERR("Error allocating %ld bytes! No "
			   "applications saved...\n",
				(long int)(sizeof(app_config) * total_cnt));
		return;
	}
	for(avp = msg->avpList.head; avp; avp = avp->next) {

		switch(avp->code) {
			case AVP_Auth_Application_Id:
				id = get_4bytes(avp->data.s);
				add_peer_application(p, id, 0, DP_AUTHORIZATION);
				avp_vendor = AAAFindMatchingAVP(
						msg, 0, AVP_Supported_Vendor_Id, 0, 0);
				while(avp_vendor) {
					vendor = get_4bytes(avp_vendor->data.s);
					LM_DBG("Found Supported Vendor for Application %i: %i\n",
							DP_AUTHORIZATION, vendor);
					add_peer_application(p, id, vendor, DP_AUTHORIZATION);
					if(!avp_vendor->next)
						break;
					avp_vendor = AAAFindMatchingAVP(msg, avp_vendor->next,
							AVP_Supported_Vendor_Id, 0, AAA_FORWARD_SEARCH);
				}
				break;
			case AVP_Acct_Application_Id:
				id = get_4bytes(avp->data.s);
				add_peer_application(p, id, 0, DP_ACCOUNTING);
				avp_vendor = AAAFindMatchingAVP(
						msg, 0, AVP_Supported_Vendor_Id, 0, 0);
				while(avp_vendor) {
					vendor = get_4bytes(avp_vendor->data.s);
					LM_DBG("Found Supported Vendor for Application %i: %i\n",
							DP_ACCOUNTING, vendor);
					add_peer_application(p, id, vendor, DP_ACCOUNTING);
					if(!avp_vendor->next)
						break;
					avp_vendor = AAAFindMatchingAVP(msg, avp_vendor->next,
							AVP_Supported_Vendor_Id, 0, AAA_FORWARD_SEARCH);
				}
				break;
			case AVP_Vendor_Specific_Application_Id:
				group = AAAUngroupAVPS(avp->data);
				avp_vendor = AAAFindMatchingAVPList(
						group, group.head, AVP_Vendor_Id, 0, 0);
				avp2 = AAAFindMatchingAVPList(group, group.head,
						AVP_Auth_Application_Id, 0, AAA_FORWARD_SEARCH);
				if(avp_vendor && avp2) {
					vendor = get_4bytes(avp_vendor->data.s);
					id = get_4bytes(avp2->data.s);
					add_peer_application(p, id, vendor, DP_AUTHORIZATION);
				}
				avp2 = AAAFindMatchingAVPList(group, group.head,
						AVP_Acct_Application_Id, 0, AAA_FORWARD_SEARCH);
				if(avp_vendor && avp2) {
					vendor = get_4bytes(avp_vendor->data.s);
					id = get_4bytes(avp2->data.s);
					add_peer_application(p, id, vendor, DP_ACCOUNTING);
				}
				AAAFreeAVPList(&group);
				break;
		}
	}
}

/**
 * Process a Capability Exchange Answer.
 * \note Must be called with a lock on the peer.
 * @param p - the peer that the CEA was received from
 * @param cea - the CEA message
 * @returns the result-code from CEA or AAA_UNABLE_TO_COMPLY if no result-code found
 */
int Process_CEA(peer *p, AAAMessage *cea)
{
	AAA_AVP *avp;
	int result_code = AAA_UNABLE_TO_COMPLY;

	avp = AAAFindMatchingAVP(cea, cea->avpList.head, AVP_Result_Code, 0, 0);
	save_peer_applications(p, cea);
	if(avp && avp->data.len >= 4) {
		result_code = get_4bytes(avp->data.s);
	}
	AAAFreeMessage(&cea);

	return result_code;
}

/**
 * Initiator - disconnect peer.
 * \note Must be called with a lock on the peer.
 * @param p - the peer to disconnect
 */
void I_Disc(peer *p)
{
	if(p->I_sock >= 0) {
		close(p->I_sock);
		p->I_sock = -1;
	}
}

/**
 * Receiver - disconnect peer.
 * \note Must be called with a lock on the peer.
 * @param p - the peer to disconnect
 */
void R_Disc(peer *p)
{
	if(p->R_sock >= 0) {
		close(p->R_sock);
		p->R_sock = -1;
	}
}

/**
 * Process a Diameter Watch-dog Request.
 * The last activity timer is updated in the sm_process(), on any message received.
 * \note Must be called with a lock on the peer.
 * @param p - the peer that the DWR was received from
 * @param dwr - the DWR message
 * @returns AAA_SUCCESS
 */
int Process_DWR(peer *p, AAAMessage *dwr)
{
	return AAA_SUCCESS;
}

/**
 * Process a Diameter Watch-dog Answer.
 * The flag for waiting a DWA is reseted.
 * \note Must be called with a lock on the peer.
 * @param p - the peer that the DWR was received from
 * @param dwa - the DWA message
 */
void Process_DWA(peer *p, AAAMessage *dwa)
{
	p->waitingDWA = 0;
	AAAFreeMessage(&dwa);
}

/**
 * Sends a Diameter Watch-dog Request.
 * The flag for waiting a DWA is set.
 * \note Must be called with a lock on the peer.
 * @param p - the peer that the DWR was received from
 */
void Snd_DWR(peer *p)
{
	AAAMessage *dwr = 0;

	dwr = AAANewMessage(Code_DW, 0, 0, 0);
	if(!dwr)
		return;
	dwr->hopbyhopId = next_hopbyhop();
	dwr->endtoendId = next_endtoend();
	if(p->state == I_Open) {
		LM_DBG("sending in state I_Open\n");
	}
	peer_send_msg(p, dwr);
}

/**
 * Sends a Diameter Watch-dog Answer.
 * \note Must be called with a lock on the peer.
 * @param p - the peer that the DWR was received from
 * @param dwr - the DWR message
 * @param result_code - the Result-Code to attach to DWA
 * @param sock - socket to send on
 */
void Snd_DWA(peer *p, AAAMessage *dwr, int result_code, int sock)
{
	AAAMessage *dwa;
	char x[4];

	dwa = AAANewMessage(Code_DW, 0, 0, dwr);
	if(!dwa)
		goto done;

	set_4bytes(x, result_code);
	AAACreateAndAddAVPToMessage(
			dwa, AVP_Result_Code, AAA_AVP_FLAG_MANDATORY, 0, x, 4);

	peer_send_msg(p, dwa);
done:
	AAAFreeMessage(&dwr);
}

/**
 * Sends a Disconnect Peer Request.
 * \note Must be called with a lock on the peer.
 * @param p - the peer to send to
 */
void Snd_DPR(peer *p)
{
	AAAMessage *dpr = 0;
	char x[4];

	dpr = AAANewMessage(Code_DP, 0, 0, 0);
	if(!dpr)
		return;
	dpr->hopbyhopId = next_hopbyhop();
	dpr->endtoendId = next_endtoend();

	set_4bytes(x, 0 /*busy*/);
	AAACreateAndAddAVPToMessage(
			dpr, AVP_Disconnect_Cause, AAA_AVP_FLAG_MANDATORY, 0, x, 4);

	if(p->state == I_Open) {
		LM_DBG("sending in state I_Open\n");
	}
	peer_send_msg(p, dpr);
}

/**
 * Sends a Disconnect Peer Answer.
 * \note Must be called with a lock on the peer.
 * @param p - the peer to send to
 * @param dpr - the DPR message
 * @param result_code - the Result-Code to attach to DPA
 * @param sock - socket to send on
 */
void Snd_DPA(peer *p, AAAMessage *dpr, int result_code, int sock)
{
	AAAMessage *dpa;

	dpa = AAANewMessage(Code_DP, 0, 0, dpr);
	if(dpa)
		peer_send_msg(p, dpa);
	AAAFreeMessage(&dpr);
}

/**
 * Receiver - Accept a connection.
 * \note Must be called with a lock on the peer.
 * @param p - peer identification
 * @param sock - socket to communicate through
 */
void R_Accept(peer *p, int sock)
{
	p->R_sock = sock;
	touch_peer(p);
}

/**
 * Receiver - Reject a connection.
 * \note Must be called with a lock on the peer.
 * @param p - peer identification
 * @param sock - socket to communicate through
 */
void R_Reject(peer *p, int sock)
{
	close(sock);
}

/**
 * Process a Capabilities Exchange Request.
 * Checks whether there are common applications.
 * \note Must be called with a lock on the peer.
 * @param p - peer identification
 * @param cer - the CER message
 * @returns the Result-Code of the operation, AAA_SUCCESS or AAA_NO_COMMON_APPLICATION
 */
int Process_CER(peer *p, AAAMessage *cer)
{
	int common_app = 0;
	AAA_AVP *avp, *avp_vendor, *avp2;
	AAA_AVP_LIST group;
	int i, id, vendor;
	for(avp = cer->avpList.head; avp; avp = avp->next) {
		switch(avp->code) {
			case AVP_Auth_Application_Id:
				id = get_4bytes(avp->data.s);
				for(i = 0; i < config->applications_cnt; i++)
					if(id == config->applications[i].id
							&& config->applications[i].vendor == 0
							&& config->applications[i].type == DP_AUTHORIZATION)
						common_app++;
				break;
			case AVP_Acct_Application_Id:
				id = get_4bytes(avp->data.s);
				for(i = 0; i < config->applications_cnt; i++)
					if(id == config->applications[i].id
							&& config->applications[i].vendor == 0
							&& config->applications[i].type == DP_ACCOUNTING)
						common_app++;
				break;
			case AVP_Vendor_Specific_Application_Id:
				group = AAAUngroupAVPS(avp->data);
				avp_vendor = AAAFindMatchingAVPList(
						group, group.head, AVP_Vendor_Id, 0, 0);
				avp2 = AAAFindMatchingAVPList(
						group, group.head, AVP_Auth_Application_Id, 0, 0);
				if(avp_vendor && avp2) {
					vendor = get_4bytes(avp_vendor->data.s);
					id = get_4bytes(avp2->data.s);
					for(i = 0; i < config->applications_cnt; i++)
						if(id == config->applications[i].id
								&& config->applications[i].vendor == vendor
								&& config->applications[i].type
										   == DP_AUTHORIZATION)
							common_app++;
				}
				avp2 = AAAFindMatchingAVPList(
						group, group.head, AVP_Acct_Application_Id, 0, 0);
				if(avp_vendor && avp2) {
					vendor = get_4bytes(avp_vendor->data.s);
					id = get_4bytes(avp2->data.s);
					for(i = 0; i < config->applications_cnt; i++)
						if(id == config->applications[i].id
								&& config->applications[i].vendor == vendor
								&& config->applications[i].type
										   == DP_ACCOUNTING)
							common_app++;
				}
				AAAFreeAVPList(&group);
				break;
		}
	}

	if(common_app != 0) {
		save_peer_applications(p, cer);
		return AAA_SUCCESS;
	} else
		return AAA_NO_COMMON_APPLICATION;
}

/**
 * Send a Capabilities Exchange Answer.
 * Checks whether there are common applications.
 * \note Must be called with a lock on the peer.
 * @param p - peer identification
 * @param cer - the CER message
 * @param result_code - the Result-Code to send
 * @param sock - socket to send through
 */
void Snd_CEA(peer *p, AAAMessage *cer, int result_code, int sock)
{
	AAAMessage *cea;
	unsigned int ip;
	union
	{
		struct sockaddr addr;
		struct sockaddr_in in;
		struct sockaddr_in6 in6;
	} addr_u;
	socklen_t addrlen;
	char x[18];

	cea = AAANewMessage(Code_CE, 0, 0, cer);
	if(!cea)
		goto done;

	addrlen = sizeof(addr_u);
	if(getsockname(sock, &(addr_u.addr), &addrlen) == -1) {
		LM_ERR("Error on finding local host address > %s\n", strerror(errno));
	} else {
		switch(addr_u.addr.sa_family) {
			case AF_INET:
				set_2bytes(x, 1);
				ip = htonl(addr_u.in.sin_addr.s_addr);
				set_4bytes(x + 2, ip);
				AAACreateAndAddAVPToMessage(cea, AVP_Host_IP_Address,
						AAA_AVP_FLAG_MANDATORY, 0, x, 6);
				break;
			case AF_INET6:
				set_2bytes(x, 2);
				memcpy(x + 2, addr_u.in6.sin6_addr.s6_addr, 16);
				AAACreateAndAddAVPToMessage(cea, AVP_Host_IP_Address,
						AAA_AVP_FLAG_MANDATORY, 0, x, 18);
				break;
			default:
				LM_ERR("unknown address type with family %d\n",
						addr_u.addr.sa_family);
		}
	}

	set_4bytes(x, config->vendor_id);
	AAACreateAndAddAVPToMessage(
			cea, AVP_Vendor_Id, AAA_AVP_FLAG_MANDATORY, 0, x, 4);

	AAACreateAndAddAVPToMessage(cea, AVP_Product_Name, AAA_AVP_FLAG_MANDATORY,
			0, config->product_name.s, config->product_name.len);

	set_4bytes(x, result_code);
	AAACreateAndAddAVPToMessage(
			cea, AVP_Result_Code, AAA_AVP_FLAG_MANDATORY, 0, x, 4);

	Snd_CE_add_applications(cea, p);

	peer_send(p, sock, cea, 1);
done:
	AAAFreeMessage(&cer);
}

/**
 * Perform the Election mechanism.
 * When 2 peers connect to each-other at the same moment, an election is triggered.
 * That means that based on the alphabetical relation between the FQDNs, one peer is
 * kept as winner on Initiator and that connection is kept, while the other keeps the same
 * connection as Receiver and drops its Initiator connection.
 * \note Must be called with a lock on the peer.
 * @param p - peer identification
 * @param cer - the CER message
 * @returns 1 if winning, 0 if loosing
 */
int Elect(peer *p, AAAMessage *cer)
{
	/* returns if we win the election */
	AAA_AVP *avp;
	str remote, local;
	int i, d;

	if(!cer) {
		LM_ERR("Elect cer is NULL \n");
		// return lose
		return 0;
	}

	local = config->fqdn;

	avp = AAAFindMatchingAVP(cer, cer->avpList.head, AVP_Origin_Host, 0, 0);
	if(!avp) {
		return 1;
	} else {
		remote = avp->data;
		for(i = 0; i < remote.len && i < local.len; i++) {
			d = ((unsigned char)local.s[i]) - ((unsigned char)remote.s[i]);
			if(d > 0)
				return 1;
			if(d < 0)
				return 0;
		}
		if(local.len > remote.len)
			return 1;
		return 0;
	}
}

/**
 * Sends a message to the peer.
 * \note Must be called with a lock on the peer.
 * @param p - peer to send to
 * @param msg - message to send
 */
void Snd_Message(peer *p, AAAMessage *msg)
{
	AAASession *session = 0;
	int rcode;
	int send_message_before_session_sm = 0;
	LM_DBG("called to peer [%.*s] for %s with code %d \n", p->fqdn.len,
			p->fqdn.s, is_req(msg) ? "request" : "response", msg->commandCode);
	if(msg->sessionId)
		session = cdp_get_session(msg->sessionId->data);

	if(session) {
		LM_DBG("There is a session of type %d\n", session->type);
		switch(session->type) {
			case ACCT_CC_CLIENT:
				if(is_req(msg)) {
					LM_DBG("this is a request for CC app\n");
					cc_acc_client_stateful_sm_process(
							session, ACC_CC_EV_SEND_REQ, msg);
					session = 0;
				} else {
					LM_DBG("this is a response to CC app\n");
				}
				break;
			case AUTH_CLIENT_STATEFULL:
				if(is_req(msg)) {
					auth_client_statefull_sm_process(
							session, AUTH_EV_SEND_REQ, msg);
					session = 0;
				} else {
					if(msg->commandCode == IMS_ASA) {
						if(!msg->res_code) {
							msg->res_code = AAAFindMatchingAVP(
									msg, 0, AVP_Result_Code, 0, 0);
						}
						if(!msg->res_code) {
							auth_client_statefull_sm_process(
									session, AUTH_EV_SEND_ASA_UNSUCCESS, msg);
							session = 0;
						} else {
							rcode = get_4bytes(msg->res_code->data.s);
							if(rcode >= 2000 && rcode < 3000) {
								peer_send_msg(p, msg);
								send_message_before_session_sm = 1;
								auth_client_statefull_sm_process(
										session, AUTH_EV_SEND_ASA_SUCCESS, msg);
								session = 0;
							} else {
								auth_client_statefull_sm_process(session,
										AUTH_EV_SEND_ASA_UNSUCCESS, msg);
								session = 0;
							}
						}

					} else {
						auth_client_statefull_sm_process(
								session, AUTH_EV_SEND_ANS, msg);
						session = 0;
					}
				}
				break;
			case AUTH_SERVER_STATEFULL:
				LM_DBG("this message is matched here to see what request or "
					   "reply it is\n");
				if(is_req(msg)) {
					if(msg->commandCode == IMS_ASR) {
						LM_DBG("ASR\n");
						auth_server_statefull_sm_process(
								session, AUTH_EV_SEND_ASR, msg);
						session = 0;
					} else {
						//would be a RAR but ok!
						LM_DBG("other request\n");
						auth_server_statefull_sm_process(
								session, AUTH_EV_SEND_REQ, msg);
						session = 0;
					}
				} else {
					if(msg->commandCode == IMS_STR) {
						LM_DBG("STA\n");
						auth_server_statefull_sm_process(
								session, AUTH_EV_SEND_STA, msg);
						session = 0;
					} else {
						LM_DBG("other reply\n");
						auth_server_statefull_sm_process(
								session, AUTH_EV_SEND_ANS, msg);
						session = 0;
					}
				}
				break;
			default:
				break;
		}
		if(session)
			AAASessionsUnlock(session->hash);
	}
	if(!send_message_before_session_sm)
		peer_send_msg(p, msg);
}

/**
 * Processes an incoming message.
 * This actually just puts the message into a message queue. One worker will pick-it-up
 * and do the actual processing.
 * \note Must be called with a lock on the peer.
 * @param p - peer received from
 * @param msg - the message received
 */
void Rcv_Process(peer *p, AAAMessage *msg)
{
	AAASession *session = 0;
	int nput = 0;

	if(!msg) {
		return;
	}

	if(msg->sessionId)
		session = cdp_get_session(msg->sessionId->data);

	if(session) {
		switch(session->type) {
			case ACCT_CC_CLIENT:
				if(is_req(msg)) {
					cc_acc_client_stateful_sm_process(
							session, ACC_CC_EV_SESSION_MODIFIED, msg);
					session = 0;
				} else {
					cc_acc_client_stateful_sm_process(
							session, ACC_CC_EV_RECV_ANS, msg);
					session = 0;
				}
				break;
			case AUTH_CLIENT_STATEFULL:
				if(is_req(msg)) {
					if(msg->commandCode == IMS_ASR)
						auth_client_statefull_sm_process(
								session, AUTH_EV_RECV_ASR, msg);
					else
						auth_client_statefull_sm_process(
								session, AUTH_EV_RECV_REQ, msg);
					session = 0;
				} else {
					if(msg->commandCode == IMS_STA)
						nput = auth_client_statefull_sm_process(
								session, AUTH_EV_RECV_STA, msg);
					else
						auth_client_statefull_sm_process(
								session, AUTH_EV_RECV_ANS, msg);
					session = 0;
				}
				break;
			case AUTH_SERVER_STATEFULL:
				if(is_req(msg)) {
					if(msg->commandCode == IMS_STR) {
						auth_server_statefull_sm_process(
								session, AUTH_EV_RECV_STR, msg);
					} else {
						auth_server_statefull_sm_process(
								session, AUTH_EV_RECV_REQ, msg);
					}
					session = 0;
				} else {
					if(msg->commandCode == IMS_ASA)
						auth_server_statefull_sm_process(
								session, AUTH_EV_RECV_ASA, msg);
					else
						auth_server_statefull_sm_process(
								session, AUTH_EV_RECV_ANS, msg);
					session = 0;
				}
				break;
			default:
				AAASessionsUnlock(session->hash);
				session = 0;
				break;
		}
	} else {
		if(msg->sessionId) {
			if(msg->commandCode == IMS_ASR)
				auth_client_statefull_sm_process(0, AUTH_EV_RECV_ASR, msg);
		}
	}
	if(!nput && !put_task(p, msg)) {
		LM_ERR("Queue refused task\n");
		AAAFreeMessage(&msg);
	}
	//if (msg) LM_ERR("task added to queue command %d, flags %#1x endtoend %u hopbyhop %u\n",msg->commandCode,msg->flags,msg->endtoendId,msg->hopbyhopId);

	//	AAAPrintMessage(msg);
}
