/*****************************************************************************
* server_v2.c	X25 API: SVC Server Application
*
* Author(s):	Nenad Corbic <ncorbic@sangoma.com>
*
* Copyright:	(c) 1995-2000 Sangoma Technologies Inc.
*
*		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.
* ============================================================================
*
* Description:
*
* 	The server.c utility will accept, user defined number, of 
* 	outgoing calls and tx/rx, user defined number, of packets on each
* 	active svc.  
*
* 	This utility should be used as an architectual model.  It is up to
* 	the user to handle all conditions of x25.  Please refer to the
* 	X25API programming manual for futher details.
*/


#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <signal.h>
#include <time.h>
#include <netinet/in.h>
#include <linux/if_wanpipe.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <wait.h>
#include <linux/wanpipe.h>
#include <linux/sdla_x25.h>
#include <linux/if_ether.h>

#define FALSE	0
#define TRUE	1


#define TX_PACKET_LEN	128	
#define NO_FRMS_TO_TX   100	
#define MAX_RX_PKT_LEN  4096

#define MAX_X25_ADDR_SIZE	16
#define MAX_X25_DATA_SIZE 	129
#define MAX_X25_FACL_SIZE	110

#define MAX_SOCK_NUM 255

#define TIMEOUT 10

#define NOWAIT_ON_CONNECT 1

#define CLEAR_NO_WAIT 0x00
#define CLEAR_WAIT_FOR_DATA 0x80

#define LISTEN 0


/* A single packet will be used to simulate tx data */
unsigned char Tx_data[TX_PACKET_LEN + sizeof(x25api_hdr_t)];

/* A singel Rx buffer will be used to accept incoming
 * data.  The buffer will be overwritten with each new
 * packet. */
unsigned char Rx_data[MAX_RX_PKT_LEN];


/* For each socket created, we will keep the
 * socket file descriptor and tx/rx pkt counts */
typedef struct sock_api {
	int sock;
	int tx;
	int rx;
}sock_api_t;

sock_api_t sock_fd[MAX_SOCK_NUM];

int max_sock_fd=0;



/*============================================================
 * Function Prototypes 
 *===========================================================*/
int MakeConnection( char * );
void socket_event_handler( void);
void setup_signal_handlers (void);
void quit (int);
void handle_oob_event(x25api_t* api_hdr, int sk_index);
int issue_clear_call(int i, int opt);
int CreateListenSock( char * );
int accept_incoming_call(int sock);




/* Defined global so it would only get allocated once.  
 * If it was defined in MakeConnection() function it 
 * would be allocated and dealocated every time we 
 * run that function.
 */  
x25api_t api_cmd;
int con_max=MAX_SOCK_NUM;
int tx_pkt=NO_FRMS_TO_TX;

#define APP_NAME "[server]"

void sig_chld (int sigio)
{
	pid_t pid;
	int stat;

	while ((pid=waitpid(-1,&stat,WNOHANG)) > 0){
		printf("Child %d terminated\n",pid);
	}

	return;
}

/*=============================================================
 * Main:
 *
 *    o Make a socket connection to the driver.
 *    o Call send_socket() to transmit data
 *
 *============================================================*/   

int main(int argc, char* argv[])
{
	pid_t pid;
	int stat;
	int i;
	
	if (argc != 2){
		printf("Usage: ./wait_client <card name> \n");
		exit(0);
	}

	signal(SIGCHLD,&sig_chld);

	memset(sock_fd,0,sizeof(sock_fd));

	sock_fd[LISTEN].sock = CreateListenSock(argv[argc-1]);
	
	if (sock_fd[LISTEN].sock <= 0)
		return -EINVAL;
	
	max_sock_fd = sock_fd[LISTEN].sock;

	socket_event_handler();	

	//Clean up
	for (i=0;i<MAX_SOCK_NUM;i++){
		if (sock_fd[i].sock){
			close(sock_fd[i].sock);
		}
		memset(&sock_fd[i],0,sizeof(sock_api_t));
	}	


	/* Wait for the clear call children */
	while ((pid=waitpid(-1,&stat,WUNTRACED)) > 0){
		printf("Child %d terminated\n",pid);
	}

	return 0;
};


/***************************************************
*  socket_event_handler
*
*   o Send and Receive data via socket 
*   o Create a tx packet using x25api_t data type. 
*   o Both the tx and rx packets contains 16 bytes headers
*     in front of the real data.  It is the responsibility
*     of the applicatino to insert this 16 bytes on tx, and
*     remove the 16 bytes on rx.
*
*	------------------------------------------
*      |  16 bytes      |        X bytes        ...
*	------------------------------------------
* 	   Header              Data
*
*   o 16 byte Header: data structure:
*
*     	typedef struct {
*		unsigned char  qdm	PACKED;	Q/D/M bits 
*		unsigned char  cause	PACKED;	cause field 
*		unsigned char  diagn	PACKED; diagnostics 
*		unsigned char  pktType  PACKED; 
*		unsigned short length   PACKED;
*		unsigned char  result	PACKED;
*		unsigned short lcn	PACKED;
*		char reserved[7]	PACKED;
*	}x25api_hdr_t;
*
*	typedef struct {
*		x25api_hdr_t hdr	PACKED;
*		char data[X25_MAX_DATA]	PACKED;
*	}x25api_t;
*
* TX DATA:
* --------
* 	Each tx data packet must contain the above 16 byte header!
* 	
* 	Only relevant byte in the 16 byte tx header, is the
* 	QDM byte.  The driver will look at this byte to determine
* 	if the Mbit (more data bit) should be set.
* 		
*       QDM: byte is a bit map of three bits:
*
* 	Q bit: Bit 2 : Qualifier bit, special kind of packet.
*                      Can be used as control packet.  
*       D bit: Bit 1 : Data acknolwedge bit. The remote will
*                      acknowledge every packet sent.
*       M bit: Bit 0 : If your packet is greater than x25 MTU,
*                      i.e 1024 bytes, than cut the packet to MTU size
*                          and set the M bit to indicate more data.                
*
* RX DATA:
* --------
* 	Each rx data will contain the above 16 byte header!
*
* 	Relevant bytes in the 16 byte rx header, are the
* 	LCN and QDM bytes.
*
*	QDM: byte is a bit map of three bits:
*
* 	Q bit: Bit 2 : Qualifier bit, special kind of packet.
*                      Can be used as control packet.  
*       D bit: Bit 1 : Data acknolwedge bit. The remote will
*                      acknowledge every packet sent.
*       M bit: Bit 0 : If your packet is greater than x25 MTU,
*                      i.e 1024 bytes, than cut the packet to MTU size
*                          and set the M bit to indicate more data.  
*                          
* 	LCN = contains the lcn number for the rx frame.
* 	
* OOB DATA:
* ---------
* 	The OOB (out of band) data is used by the driver to 
* 	indicate x25 events for the active channel: 
* 	clear call, or restarts.
*
* 	Each OOB packet contains the above 16 byte header!
*
*	Relevant bytes in the 16 byte oob header, are the
*	pktType, cause and diagn bytes.
*
*	pktType = event type (ex Clear Call, Restart ...)
*	cause   = x25 cause of the event
*	diagn   = x25 diagnostic information used to determine
*	          the cause of the event.
*
*	Upon receiving an event, the sock should be considered 
*	DEAD!!!  Meaning it must be closed using the close()
*	function.
*/

void socket_event_handler(void)
{
	unsigned short Tx_lgth,timeout=0;
	int err=0, i; 
	struct timeval tv;
	x25api_t* api_tx_el;
	fd_set	writeset,readset,oobset;

	/* Setup a timeout value for the select statement, which is
	 * going to block until the socket(s) are/is ready to tx/rx
	 * or oob.  In this case we will timeout afte 10 seconds of
	 * inactivity */
	tv.tv_usec = 0; 
	tv.tv_sec = 10;

	/* Initialize the tx packet length */
	Tx_lgth = TX_PACKET_LEN;


	/* Cast the x25 16 byte header to the begining
	 * of the tx packet.  Using the pointer fill 
	 * in appropriate header information such as
	 * QDM bits */
	api_tx_el = (x25api_t *)Tx_data;

	/* Initialize the 16 byte header */
	memset(api_tx_el, 0, sizeof(x25api_hdr_t));

	/* Set the Mbit (more bit) 
	 * currently this option is disabled */
#ifdef _MORE_BIT_SET_
	api_tx_el->hdr.qdm = 0x01
#endif	
		
	/* Fill in the tx packet data with arbitrary
	 * information */ 
	for (i=0; i<Tx_lgth ; i++){
               	api_tx_el->data[i] = (unsigned char) i;
	}


	/* Start an infinite loop which will tx/rx data 
	 * over connected x25 svc's */

	for(;;) {

		/* Initialize select() flags */
		FD_ZERO(&readset);
		FD_ZERO(&oobset);
		FD_ZERO(&writeset);
		
		/* For all connected sockets, tell the select
		 * what to wait for.  Tx, Rx and OOB */
		for (i=0;i<con_max;i++){
			if (!sock_fd[i].sock)
				continue;
			
			FD_SET(sock_fd[i].sock,&readset);
			FD_SET(sock_fd[i].sock,&oobset);
			FD_SET(sock_fd[i].sock,&writeset);
		}
		
		/* The select function must be used to implement flow control.
	         * WANPIPE socket will block the user if the socket cannot send
		 * or there is nothing to receive.
		 *
		 * By using the last socket file descriptor +1 select will wait
		 * for all active x25 sockets.
		 *
		 * If the NONBLOCKING option has been used during connect()
		 * the select will wait untill the channel is connected 
		 * (i.e. accept has been received).  Once the channel is connected
		 * the tx and rx will start.  However, if the call is cleared for
		 * any reason, the OOB message will indicate that event.
		 */ 
		
	        if((err=select(max_sock_fd + 1,&readset, &writeset, &oobset, NULL /*&tv*/))){

			/* One of the sockets returned OK for tx rx or oob 
			 * Thus, for all waiting connections, check each flag */
			
			for (i=0;i<con_max;i++){
		
				if (!sock_fd[i].sock)
					continue;
			

				/* First check for OOB messages */
				
				if (FD_ISSET(sock_fd[i].sock,&oobset)){

					/* The OOB Message will indicate that an 
					 * asynchronous event occured.  The applicaton 
					 * must stop everything and check the state of 
					 * the link.  Since link might  
					 * have gone down */

					/* In this example I just exit. A real 
					 * application would check the state of the 
					 * sock first by reading the header information. 
					 */

					/* IMPORTANT:
					 * If we fail to read the OOB message, we can 
					 * assume that the link is down.  Thus, close 
					 * the socket and continue !!! */

					err = recv(sock_fd[i].sock, Rx_data, sizeof(Rx_data), MSG_OOB);
			
					/* err contains number of bytes transmited */		
					if(err < 0 ) {

						/* The state of the socket is disconnected.
						 * We must close the socket and continue with
						 * operation */
						printf("%s: SockId=%i : OOB Event : Disconnected\n",
								APP_NAME,sock_fd[i].sock);

						if (i == LISTEN){
							/* If we received an OOB message
							 * on listen socket, the x25 link
							 * has gone down, due to lapb,
							 * or physical layer.
							 *
							 * We can run liste() call to re-bind
							 * to socket to the driver and wait
							 * in select() for the x25 link to come
							 * up.
							 * 
							 * If listen() fails, the driver is being
							 * shutdown and we must exit. */

							if (listen(sock_fd[i].sock,0) == 0){
								/* Listen re-binded ok, thus
								 * skip the section below */
								continue;
							}
						}
						

						memset(&api_cmd,0,sizeof(api_cmd));
						if ((err=ioctl(sock_fd[i].sock,SIOC_WANPIPE_GET_CALL_DATA,&api_cmd)) == 0){
							handle_oob_event(&api_cmd, i);
						}else{
							close(sock_fd[i].sock);
							sock_fd[i].sock=0;
						}
						
						/* Do what ever you have to do to handle
						 * this condiditon */
					}else{

						/* OOB packet received OK ! */
						
						api_tx_el = (x25api_t *)Rx_data;
						handle_oob_event(api_tx_el, i);
					}
					goto tx_rx_end;
				}

				
				if (FD_ISSET(sock_fd[i].sock,&readset)){

					
					/* If there are pending rx packets
					 * for a LISTEN socket, it means that
					 * calls are pending.  Thus, accept 
					 * a pending call */
					if (i==LISTEN){
						accept_incoming_call(sock_fd[LISTEN].sock);

						/* We should break, so we go back to select 
						 * thus, if there is another call to be accepted
						 * it will have priority */
						break;
					}

					
					/* This socket has received a packet. */
					
					err = recv(sock_fd[i].sock, Rx_data, sizeof(Rx_data), 0);
					
					/* err contains number of bytes transmited */		
					if(err < 0 ) {
						
						/* This should never happen. Assume the channel
						 * has been cleared.  */
						printf("%s: Sockid=%i : Failed to rcv packet %i\n",
								APP_NAME,
								sock_fd[i].sock,
								err);
						close(sock_fd[i].sock);
						sock_fd[i].sock=0;
						
					}else{

						/* Packet received OK !
						 *
						 * Every received packet comes with the 16
						 * bytes of header which driver adds on. 
						 * Header is structured as x25api_hdr_t. 
						 * (same as above)
						 */
						
						x25api_hdr_t *api_data = 
								(x25api_hdr_t *)Rx_data;
				
						printf("%s: SockId=%i : RX : size=%i, qdm=0x%02X, cnt=%i\n", 
							  APP_NAME,
							  sock_fd[i].sock, 
							  err,
							  api_data->qdm, 
							  ++sock_fd[i].rx);

						if (api_data->qdm & 0x01){
							/* More bit is set, thus
							 * handle it accordingly */
						}
					}
				}

				
				if (FD_ISSET(sock_fd[i].sock,&writeset)){
					
					/* This socket is ready to tx */
					
					/* The tx packet length contains the 16 byte
					 * header. The tx packet was created above. */
					err = send(sock_fd[i].sock, Tx_data, 
						   Tx_lgth + sizeof(x25api_hdr_t), 0);

					/* err contains number of bytes transmited */		
					if (err>0){
						printf("%s: SockId=%i : TX : Cnt=%i\n",
								APP_NAME,
								sock_fd[i].sock,
								++sock_fd[i].tx);
					}				
					
					/* If err<=0 it means that the send failed and that
					 * driver is busy.  Thus, the packet should be
					 * requeued for re-transmission on the next
					 * try !!!! 
					 */


					/* In this example I am clearing the connection
					 * after I sent user specified number of packets */
					//if (sock_fd[i].tx >= tx_pkt){
					//	issue_clear_call(i, CLEAR_WAIT_FOR_DATA);
					//}	
				}
				
			}
tx_rx_end:
			for (i=0;i<con_max;i++){
				if (sock_fd[i].sock)
					break;
			}

			/* All channels are down ! */
			if (i>=con_max)
				break;

		}else{

			/* select timeout occured.  The svc could be 
			 * waiting for the accept, or there is something wrong
			 * with the x25 configuration. 
			 *
			 * It is up to the user to handle this condition
			 * as they see fit */
			
			if (err == 0){
				if (++timeout == 5){
					printf("Select() timeout exceeded MAXIMUM\n");
					break;			
				}		
				printf("Select() timeout try again !!!\n");
			}else{
				printf("Error in Select() !!!\n");
				break;
			}
		}//if select
	}//for

	for (i=0;i<con_max;i++){
		if (!sock_fd[i].sock)
			continue;
		
		ioctl(sock_fd[i].sock,SIOC_WANPIPE_CLEAR_CALL,NULL);
		close(sock_fd[i].sock);
		sock_fd[i].sock=0;
	}
} 


void handle_oob_event(x25api_t* api_hdr, int sk_index)
{

	switch (api_hdr->hdr.pktType){

		case ASE_RESET_RQST:
			printf("%s: SockId=%i : OOB : Rx Reset Call : Lcn=%i : diag=0x%02X : cause=0x%02X\n",
					APP_NAME,
					sock_fd[sk_index].sock,
					api_hdr->hdr.lcn,
					api_hdr->hdr.diagn,
					api_hdr->hdr.cause);

			/* NOTE: we don't have to close the socket,
			 * since the reset doesn't clear the call
			 * however, it means that there is something really
			 * wrong and that data has been lost */
			return;
		
		
		case ASE_CLEAR_RQST:
			printf("%s: SockId=%i : OOB : Rx Clear Call : Lcn=%i : diag=0x%02X : cause=0x%02X\n",
					APP_NAME,
					sock_fd[sk_index].sock,
					api_hdr->hdr.lcn,
					api_hdr->hdr.diagn,
					api_hdr->hdr.cause);
			break;		
			
		case ASE_RESTART_RQST:
			printf("%s: SockId=%i : OOB : Rx Restart Req : Lcn=%i : diag=0x%02X : cause=0x%02X\n",
					APP_NAME,
					sock_fd[sk_index].sock,
					api_hdr->hdr.lcn,
					api_hdr->hdr.diagn,
					api_hdr->hdr.cause);
			
			break;
		case ASE_INTERRUPT:
			printf("%s: SockId=%i : OOB : Rx Interrupt Req : Lcn=%i : diag=0x%02X : cause=0x%02X\n",
					APP_NAME,
					sock_fd[sk_index].sock,
					api_hdr->hdr.lcn,
					api_hdr->hdr.diagn,
					api_hdr->hdr.cause);
			
			break;


		default:
			printf("%s: SockId=%i : OOB : Rx Type=0x%02X : Lcn=%i : diag=0x%02X : cause=0x%02X\n",
					APP_NAME,
					sock_fd[sk_index].sock,
					api_hdr->hdr.pktType,
					api_hdr->hdr.lcn,
					api_hdr->hdr.diagn,
					api_hdr->hdr.cause);
			break;
	}
	close(sock_fd[sk_index].sock);
	sock_fd[sk_index].sock=0;
}

/* ============================================================
 * issue_clear_call
 *
 * Input options (opt):
 * 	CLEAR_WAIT_FOR_DATA : Fail the clear call if data is
 * 	                      still pending the transmisstion.
 * 	                      This way tx data is not lost 
 * 	                      due to the clear call.
 * 	CLEAR_NO_WAIT: 	      Clear call regardless of current
 * 	                      pending data.
 *
 * NOTE: This function can block, which can cause buffer
 *       overrun on other lcn's.  Thus, it should be executed
 *       in a separate process.
 */ 

int issue_clear_call(int i, int opt)
{
	volatile int err=0;

	//FIXME: Fork is expensive use Pthread
	if (!fork()){
		memset(&api_cmd,0,sizeof(api_cmd));
		api_cmd.hdr.qdm=opt;
		for (;;){
			err=ioctl(sock_fd[i].sock,SIOC_WANPIPE_CLEAR_CALL,&api_cmd);
			if (!err)
				break;

			//printf("\t%s: SockId=%i: Clear Call Failed : Busy - Trying agin =%i!\n",
			//		APP_NAME, sock_fd[i].sock,err);

			/* If the state is disconnected, the call has been
			 * cleared, thus break out */
			if (ioctl(sock_fd[i].sock,SIOC_WANPIPE_SOCK_STATE,0) == 1){
				break;
			}
			usleep(100);
		}
		printf("%s: SockId=%i: Call Cleared !\n",
				APP_NAME,
				sock_fd[i].sock);

		close(sock_fd[i].sock);
		sock_fd[i].sock=0;
	}else{
		close(sock_fd[i].sock);
		sock_fd[i].sock=0;
	}
	return 0;
}

int accept_incoming_call(int sock)
{
	int sock1=0;
	int err;
	int index=-1;
	
	for (index=0; index < MAX_SOCK_NUM; index++){	
		if (!sock_fd[index].sock)
			break;
	}
		
	if (index >= MAX_SOCK_NUM){
		printf("%s: Maximum incoming SVCs reached!\n",APP_NAME);
		return -EINVAL;
	}
	
	sock1 = accept(sock,NULL,NULL);

	if (sock1 <= 0){
		printf ("%s: Sock Accept call failed ! new sock=%i\n",APP_NAME,sock1);
		return -EINVAL;
	}	

	if ((err=ioctl(sock1,SIOC_WANPIPE_GET_CALL_DATA,&api_cmd)) != 0){
		printf("%s: Failed to get accept call data %i\n",APP_NAME,err);
		close(sock1);
		return -EINVAL;
	}else{
		api_cmd.data[api_cmd.hdr.length]=0;
	}
	
	if ((err=ioctl(sock1,SIOC_WANPIPE_ACCEPT_CALL,0)) != 0){
		printf("%s: Accept call failed %i\n",APP_NAME,err);
		close(sock1);
		return -EINVAL;
	}else{
		printf("%s: Call Accept on LCN=%i\n",APP_NAME,api_cmd.hdr.lcn);
	}

	sock_fd[index].sock = sock1;
	if (sock1 > max_sock_fd){
		max_sock_fd=sock1;
	}
		
	return 0;
}


/***************************************************
* CreateListenSock
*
*   o Create a Socket
*   o Bind a socket to a wanpipe network interface
*/         

int CreateListenSock (char *i_name ) 
{
	int sock=0;
	struct wan_sockaddr_ll 	sa;

	memset(&sa,0,sizeof(struct wan_sockaddr_ll));

	/* Create a new socket */
   	sock = socket( AF_WANPIPE, SOCK_RAW, 0);
   	if( sock < 0 ) {
      		perror("Socket");
      		return -EINVAL;
   	} 

	/* Fill in binding information 
	 * before we use connect() system call
         * a socket must be binded into a virtual
         * network interface svc_connect.
         * 
         * Card name must be supplied as well. In 
         * this case the user supplies the name
         * eg: wanpipe1.
         */ 
	sa.sll_family = AF_WANPIPE;
	sa.sll_protocol = htons(X25_PROT);
	strcpy(sa.sll_device, "svc_listen");
	strcpy(sa.sll_card, i_name);
	

	/* Bind a sock using the above address structure */
        if(bind(sock, (struct sockaddr *)&sa, sizeof(struct wan_sockaddr_ll)) == -1){
                perror("bind");
		printf("Failed to bind socket to %s interface\n",i_name);
		close(sock);
               	return -EINVAL;
        }

	if (listen(sock,500) != 0){
		close(sock);
		return -EINVAL;
	}

	return sock;
}