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