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QUICKB.C
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1988-09-24
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25KB
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/*
** QUICKB.C - Quick B Protocol Support routines
**
** converted to C by Paul M. Resch
** adapted to LiteComm(tm) ToolBox by Information Technology, Ltd.
*/
/*
** This module implements the B-Protocol Functions.
**
** bp_DLE should be invoked whenever a <DLE> is received.
** bp_ENQ should be called whenever an <ENQ> is received.
** bp_ESC_I should be called when the sequence <ESC><I> is received.
**
** This source was originally derived from QUICKB.INC, written by
** Russ Ranshaw, CompuServe Incorporated.
**
*/
#include "litecomm.h"
#include "litexm.h"
#include <vcstdio.h>
#include <dos.h>
#ifdef M_I86
#include <stdlib.h>
#include <fcntl.h>
#include <io.h>
#include <sys\types.h>
#include <sys\stat.h>
#endif
#ifdef __TURBOC__
#include <conio.h>
#include <fcntl.h>
#include <io.h>
#include <stat.h>
#endif
extern unsigned int port; /* defined in TTL main */
#define TRUE 1
#define FALSE 0
#undef DLE
#undef NAK
#define DLE 16
#define ETX 03
#define NAK 21
#define ENQ 05
#define CR 0x0D
#define LF 0x0A
#define MAX_BUF_SIZE 1032 /* Largest data block we can handle */
#define MAX_SA 2 /* Maximum number of waiting packets */
#define DEF_BUF_SIZE 511 /* Default data block */
#define DEF_WS 1 /* I can send 2 packets ahead */
#define DEF_WR 1 /* I can receive single send-ahead */
#define DEF_BS 8 /* I can handle 1024 bytes */
#define DEF_CM 1 /* I can handle CRC */
#define DEF_DQ 1 /* I can handle non-quoted NUL */
#define MAX_ERRORS 10
#define incr_seq(v) (v == 9 ? 0 : v+1) /* macro to incr seq number */
#define incr_SA(v) (v == MAX_SA ? 0 : v + 1 )
#define send_enq() (lc_put(port, ENQ))
/*
** Receive States
*/
#define R_GET_DLE 0
#define R_GET_B 1
#define R_GET_SEQ 2
#define R_GET_DATA 3
#define R_GET_CHECKSUM 4
#define R_SEND_ACK 5
#define R_TIMED_OUT 6
#define R_SUCCESS 7
/*
** Send States
*/
#define S_GET_DLE 1
#define S_GET_NUM 2
#define S_HAVE_ACK 3
#define S_GET_PACKET 4
#define S_TIMED_OUT 5
#define S_SEND_NAK 6
#define S_SEND_ENQ 7
#define S_SEND_DATA 8
typedef struct PACKETB
{
int seq; /* Packet's sequence number */
int num; /* Number of bytes in packet */
unsigned char buf[MAX_BUF_SIZE]; /* Actual packet data */
} PACKET;
static PACKET SA_Buf[MAX_SA+1]; /* Send-ahead buffers */
/*
** Table of control characters that need to be masked
*/
static char mask_table[] =
{
0, 0, 0, 1, 0, 1, 0, 0, /* NUL SOH SOB ETX EOT ENQ SYN BEL */
0, 0, 0, 0, 0, 0, 0, 0, /* BS HT LF VT FF CR SO SI */
1, 1, 0, 1, 0, 1, 0, 0, /* DLE DC1 DC2 DC3 DC4 NAK ^V ^W */
0, 0, 0, 0, 0, 0, 0, 0 /* CAN ^Y ^Z ESC ? ? ? ? */
};
static char hex_digit[] = "0123456789ABCDEF";
static int seq_num; /* Current Sequence Number */
static int lchecksm; /* May hold CRC */
static int r_size; /* size of receiver buffer */
static unsigned int s_counter,
r_counter;
static int timed_out; /* we timed out before receiving */
static int cchar; /* current character */
static int masked; /* TRUE if ctrl character 'masked' */
static int packet_received; /* True if a packet was received */
static unsigned char r_buffer[MAX_BUF_SIZE];
/*
** Other End's Parameters
*/
static char His_WS; /* Sender's Window Send */
static char His_WR; /* Sender's Window Receive */
static char His_BS; /* Sender's Block Size */
static char His_CM; /* Sender's Check Method */
/*
** Negotiated Parameters
*/
static char Our_WS; /* Negotiated Window Send */
static char Our_WR; /* Negotiated Window Receive */
static char Our_BS; /* Negotiated Block Size */
static char Our_CM; /* Negotiated Check Method */
static int Quick_B; /* True if Quick B in effect */
static int Use_CRC; /* True if CRC in effect */
static int buffer_size; /* Our_BS * 4 */
static int SA_Max; /* 1 if SA not enabled, else MAX_SA */
static int SA_Enabled; /* True if Send-Ahead is permitted */
static int ack_SA; /* Which SA_Buf is waiting for ACK */
static int fill_SA; /* Which SA_Buf is ready, new data */
static int SA_Waiting; /* Num of SA_Buf's waiting for ACK */
static int blkct; /* block counter for display */
extern char strbuf[]; /* defined in qbttl */
static void do_transport_parameters(void);
static int send_packet();
static int SA_Flush();
/*
** crc
**
** Calculates XMODEM-style CRC (uses the CCITT V.41 polynomial but
** completely backwards from the normal bit ordering).
*/
static unsigned crc_table[] =
{
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};
static unsigned int crc_16;
/*
** Upd_CRC updates crc_16 and returns the updated value.
*/
static unsigned int upd_CRC (value)
unsigned int value;
{
crc_16 = crc_table [((crc_16 >> 8) ^ (value)) & 0xff] ^ (crc_16 << 8);
return( crc_16 );
}
/*
** Update the checksum/CRC
*/
static void do_checksum(c)
int c;
{
if (Quick_B && Use_CRC)
lchecksm = upd_CRC (c);
else
{
lchecksm = lchecksm << 1;
if (lchecksm > 255)
lchecksm = (lchecksm & 0xFF) + 1;
lchecksm = lchecksm + c;
if (lchecksm > 255)
lchecksm = (lchecksm & 0xFF) + 1;
}
}
static void send_failure( code )
int code;
{
register PACKET *p;
ack_SA = 0;
fill_SA = 0;
SA_Waiting = 0;
p = &SA_Buf [0];
p->buf[0] = 'F';
p->buf[1] = code;
if ( send_packet (1))
SA_Flush(); /* Gotta wait for the host to ACK it */
}
/*
** bp_ENQ is called when the terminal emulator receives the character <ENQ>
** from the host. Its purpose is to initialize for B Protocol and tell the
** host that we support Quick B.
*/
void bp_ENQ()
{
seq_num = 0;
buffer_size = 511; /* Set up defaults */
Quick_B = FALSE; /* Not Quick B Protocol */
Use_CRC = FALSE; /* Not CRC_16 */
SA_Enabled = FALSE; /* No Send-Ahead by us */
SA_Max