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/*
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#ifndef __UM_SLIP_PROTO_H__
#define __UM_SLIP_PROTO_H__
/* SLIP protocol characters. */
#define SLIP_END 0300 /* indicates end of frame */
#define SLIP_ESC 0333 /* indicates byte stuffing */
#define SLIP_ESC_END 0334 /* ESC ESC_END means END 'data' */
#define SLIP_ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
static inline int slip_unesc(unsigned char c,char *buf,int *pos, int *esc)
{
int ret;
switch(c){
case SLIP_END:
*esc = 0;
ret=*pos;
*pos=0;
return(ret);
case SLIP_ESC:
*esc = 1;
return(0);
case SLIP_ESC_ESC:
if(*esc){
*esc = 0;
c = SLIP_ESC;
}
break;
case SLIP_ESC_END:
if(*esc){
*esc = 0;
c = SLIP_END;
}
break;
}
buf[(*pos)++] = c;
return(0);
}
static inline int slip_esc(unsigned char *s, unsigned char *d, int len)
{
unsigned char *ptr = d;
unsigned char c;
/*
* Send an initial END character to flush out any
* data that may have accumulated in the receiver
* due to line noise.
*/
*ptr++ = SLIP_END;
/*
* For each byte in the packet, send the appropriate
* character sequence, according to the SLIP protocol.
*/
while (len-- > 0) {
switch(c = *s++) {
case SLIP_END:
*ptr++ = SLIP_ESC;
*ptr++ = SLIP_ESC_END;
break;
case SLIP_ESC:
*ptr++ = SLIP_ESC;
*ptr++ = SLIP_ESC_ESC;
break;
default:
*ptr++ = c;
break;
}
}
*ptr++ = SLIP_END;
return (ptr - d);
}
#endif
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
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