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/*-
* Copyright (c) 2006 M. Warner Losh. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This software is derived from software provide by Kwikbyte who specifically
* disclaimed copyright on the code. This version of xmodem has been nearly
* completely rewritten, but the CRC is from the original.
*
* $FreeBSD$
*/
#include "lib.h"
#define PACKET_SIZE 128
/* Line control codes */
#define SOH 0x01 /* start of header */
#define ACK 0x06 /* Acknowledge */
#define NAK 0x15 /* Negative acknowledge */
#define CAN 0x18 /* Cancel */
#define EOT 0x04 /* end of text */
#define TO 10
/*
* int GetRecord(char , char *)
* This private function receives a x-modem record to the pointer and
* returns non-zero on success.
*/
static int
GetRecord(char blocknum, char *dest)
{
int size;
int ch;
unsigned chk, j;
chk = 0;
if ((ch = getc(TO)) == -1)
goto err;
if (ch != blocknum)
goto err;
if ((ch = getc(TO)) == -1)
goto err;
if (ch != (~blocknum & 0xff))
goto err;
for (size = 0; size < PACKET_SIZE; ++size) {
if ((ch = getc(TO)) == -1)
goto err;
chk = chk ^ ch << 8;
for (j = 0; j < 8; ++j) {
if (chk & 0x8000)
chk = chk << 1 ^ 0x1021;
else
chk = chk << 1;
}
*dest++ = ch;
}
chk &= 0xFFFF;
if (((ch = getc(TO)) == -1) || ((ch & 0xff) != ((chk >> 8) & 0xFF)))
goto err;
if (((ch = getc(TO)) == -1) || ((ch & 0xff) != (chk & 0xFF)))
goto err;
putchar(ACK);
return (1);
err:;
putchar(CAN);
// We should allow for resend, but we don't.
return (0);
}
/*
* int xmodem_rx(char *)
* This global function receives a x-modem transmission consisting of
* (potentially) several blocks. Returns the number of bytes received or
* -1 on error.
*/
int
xmodem_rx(char *dest)
{
int starting, ch;
char packetNumber, *startAddress = dest;
packetNumber = 1;
starting = 1;
while (1) {
if (starting)
putchar('C');
if (((ch = getc(1)) == -1) || (ch != SOH && ch != EOT))
continue;
if (ch == EOT) {
putchar(ACK);
return (dest - startAddress);
}
starting = 0;
// Xmodem packets: SOH PKT# ~PKT# 128-bytes CRC16
if (!GetRecord(packetNumber, dest))
return (-1);
dest += PACKET_SIZE;
packetNumber++;
}
// the loop above should return in all cases
return (-1);
}
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