368 lines
9.2 KiB
C
368 lines
9.2 KiB
C
/*****************************************************************************
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* chdlc_api.c CHDLC API: Receive Module
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*
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* Author(s): Gideon Hack & Nenad Corbic <ncorbic@sangoma.com>
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*
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* Copyright: (c) 1995-2001 Sangoma Technologies Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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* ============================================================================
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* Description:
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*
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* The chdlc_api.c utility will bind to a socket to a chdlc network
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* interface, and continously tx and rx packets to an from the sockets.
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*
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* This example has been written for a single interface in mind,
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* where the same process handles tx and rx data.
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*
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* A real world example, should use different processes to handle
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* tx and rx spearately.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <linux/if_wanpipe.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <linux/wanpipe.h>
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#include <linux/sdla_chdlc.h>
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#define FALSE 0
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#define TRUE 1
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#define LGTH_CRC_BYTES 2
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#define MAX_TX_DATA 100 /* Size of tx data */
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#define MAX_FRAMES 1 /* Number of frames to transmit */
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#define TIMEOUT 1
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#define WRITE 1
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/*===================================================
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* Golobal data
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*==================================================*/
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unsigned short no_CRC_bytes_Rx;
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unsigned char HDLC_streaming = FALSE;
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unsigned short Rx_lgth;
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unsigned char Rx_data[16000];
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unsigned char Tx_data[MAX_TX_DATA + sizeof(api_tx_hdr_t)];
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int sock;
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/*===================================================
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* Function Prototypes
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*==================================================*/
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int MakeConnection(char *, char *);
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void process_con( void);
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/*===================================================
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* MakeConnection
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*
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* o Create a Socket
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* o Bind a socket to a wanpipe network interface
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* (Interface name is supplied by the user)
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*==================================================*/
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int MakeConnection(char *r_name, char *i_name )
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{
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struct wan_sockaddr_ll sa;
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memset(&sa,0,sizeof(struct wan_sockaddr_ll));
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errno = 0;
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sock = socket(AF_WANPIPE, SOCK_RAW, 0);
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if( sock < 0 ) {
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perror("Socket");
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return( FALSE );
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} /* if */
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printf("\nConnecting to router %s, interface %s\n", r_name, i_name);
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strcpy( sa.sll_device, i_name);
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strcpy( sa.sll_card, r_name);
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sa.sll_protocol = htons(PVC_PROT);
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sa.sll_family=AF_WANPIPE;
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if(bind(sock, (struct sockaddr *)&sa, sizeof(struct wan_sockaddr_ll)) < 0){
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perror("bind");
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printf("Failed to bind a socket to %s interface\n",i_name);
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exit(0);
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}
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printf("Socket bound to %s\n\n",i_name);
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return( TRUE );
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}
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/*===========================================================
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* process_con
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*
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* o Tx/Rx data to and from the socket
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* o Cast received data to an api_rx_element_t data type
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* o The received packet contains 16 bytes header
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*
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* ------------------------------------------
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* | 16 bytes | X bytes ...
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* ------------------------------------------
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* Header Data
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*
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* RX DATA:
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* --------
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* Each rx data packet contains the 16 byte header!
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*
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* o Rx 16 byte data structure:
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*
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* typedef struct {
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* unsigned char error_flag PACKED;
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* unsigned short time_stamp PACKED;
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* unsigned char reserved[13] PACKED;
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* } api_rx_hdr_t;
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*
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* typedef struct {
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* api_rx_hdr_t api_rx_hdr PACKED;
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* void * data PACKED;
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* } api_rx_element_t;
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*
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* error_flag:
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* bit 0: incoming frame was aborted
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* bit 1: incoming frame has a CRC error
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* bit 2: incoming frame has an overrun eror
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*
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* time_stamp:
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* absolute time value in ms.
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*
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* TX_DATA:
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* --------
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* Each tx data packet MUST contain a 16 byte header!
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*
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* o Tx 16 byte data structure
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*
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* typedef struct {
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* unsigned char attr PACKED;
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* unsigned char misc_Tx_bits PACKED;
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* unsigned char reserved[14] PACKED;
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* } api_tx_hdr_t;
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*
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* typedef struct {
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* api_tx_hdr_t api_tx_hdr PACKED;
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* void * data PACKED;
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* } api_tx_element_t;
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*
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* When device driver is configured for Switched CTS/RTS
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* or Idle Mark, the misc_Tx_bits must be used to control
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* the state of the line after the transmisstion of data is
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* complete:
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*
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* misc_Tx_bits:
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* ------------
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* 0 : No change
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*
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* DROP_RTS_AFTER_TX : Drop RTS after transmission of THIS
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* frame.
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*
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* IDLE_FLAGS_AFTER_TX : Idle flags after transmission of
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* THIS frame.
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*/
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void process_con(void)
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{
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unsigned int Rx_count,Tx_count,Tx_length;
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api_rx_element_t* api_rx_el;
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api_tx_element_t * api_tx_el;
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fd_set ready,write;
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int err,i;
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unsigned char *data;
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Rx_count = 0;
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Tx_count = 0;
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Tx_length = MAX_TX_DATA;
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/* If running HDLC_STREAMING then the received CRC bytes
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* will be passed to the application as part of the
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* received data. The CRC bytes will be appended as the
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* last two bytes in the rx packet.
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*/
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memset(&Tx_data[0],0,MAX_TX_DATA + sizeof(api_tx_hdr_t));
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/* Initialize the tx packet. The 16 byte header must
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* be inserted before tx data.
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*/
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api_tx_el = (api_tx_element_t*)&Tx_data[0];
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/* In general misc_Tx_bits are set to zero.
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* However, if device driver is configured for
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* Switched CTS/RTS or Idle Mark, the misc_Tx_bits
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* must be used as described above */
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api_tx_el->wan_api_tx_hdr.wp_api_tx_hdr_chdlc_misc_tx_bits = 0;
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/* Fill in the packet data */
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data = (unsigned char *)&api_tx_el->data;
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for (i=0;i<Tx_length;i++){
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data[i] = (unsigned char)i;
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}
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/* If drivers has been configured in HDLC_STREAMING
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* mode, the CRC bytes will be included into the
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* rx packet. Thus, the application should remove
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* the last two bytes of the frame.
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*
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* The no_CRC_bytes_Rx will indicate to the application
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* how many bytes to cut from the end of the rx frame.
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*
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*/
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no_CRC_bytes_Rx = 0; //LGTH_CRC_BYTES;
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for(;;) {
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FD_ZERO(&ready);
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FD_ZERO(&write);
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FD_SET(sock,&ready);
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#ifdef WRITE
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FD_SET(sock,&write);
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#endif
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/* The select function must be used to implement flow control.
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* WANPIPE socket will block the user if the socket cannot send
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* or there is nothing to receive.
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*
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* By using the last socket file descriptor +1 select will wait
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* for all active sockets.
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*/
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if(select(sock + 1,&ready, &write, NULL, NULL)){
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/* Check for rx packets */
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if (FD_ISSET(sock,&ready)){
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err = recv(sock, Rx_data, sizeof(Rx_data), 0);
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/* err indicates bytes received */
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if(err > 0) {
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/* Rx packet recevied OK
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* Each rx packet will contain 16 bytes of
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* rx header, that must be removed. The
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* first byte of the 16 byte header will
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* indicate an error condition.
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*/
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api_rx_el = (api_rx_element_t*)Rx_data;
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switch (api_rx_el->api_rx_hdr.wan_hdr_hdlc_error_flag){
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case 0:
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/* Rx packet is good */
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break;
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case RX_FRM_ABORT:
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/* Frame was aborted */
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case RX_FRM_CRC_ERROR:
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/* Frame has crc error */
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case RX_FRM_OVERRUN_ERROR:
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/* Frame has an overrun error */
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default:
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/* Error with the rx packet
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* handle it ... */
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break;
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}
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/* Check the packet length, after we remove
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* the 16 bytes rx header */
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Rx_lgth = err - sizeof(api_rx_hdr_t);
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if(Rx_lgth <= no_CRC_bytes_Rx) {
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printf("\nShort frame received (%d)\n",
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Rx_lgth);
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return;
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}
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/* Remove any CRC bytes from the rx packet
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* by adjusting the rx packet length */
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Rx_lgth -= no_CRC_bytes_Rx;
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printf("Received packet %i, length = %i\n",
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++Rx_count, Rx_lgth);
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} else {
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printf("\nError receiving data\n");
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break;
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}
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}
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/* Check if the socket is ready to tx data */
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if (FD_ISSET(sock,&write)){
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err = send(sock,Tx_data, Tx_length + sizeof(api_tx_hdr_t), 0);
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if (err > 0){
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/* Packet sent ok */
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printf("Packet sent: Sent %i : %i\n",
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err,++Tx_count);
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}else{
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/* The driver is busy, we must requeue this
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* tx packet, and try resending it again
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* later. */
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}
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}
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/* Stop the program afer transmitting MAX_FRAMES */
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if (Tx_count == MAX_FRAMES)
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break;
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} else {
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printf("\nError selecting socket\n");
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break;
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}
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}
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close (sock);
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}
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/***************************************************************
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* Main:
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*
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* o Make a socket connection to the driver.
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* o Call process_con() to read/write the socket
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*
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**************************************************************/
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int main(int argc, char* argv[])
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{
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int proceed;
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if (argc != 3){
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printf("Usage: rec_wan_sock <router name> <interface name>\n");
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exit(0);
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}
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proceed = MakeConnection(argv[argc - 2], argv[argc - 1]);
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if( proceed == TRUE ){
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process_con( );
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return 0;
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}
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return 1;
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};
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