[mirror_ubuntu-zesty-kernel.git] / arch / um / drivers / slip_common.h

#ifndef __UM_SLIP_COMMON_H
#define __UM_SLIP_COMMON_H

#define BUF_SIZE 1500
 /* two bytes each for a (pathological) max packet of escaped chars +  *
  * terminating END char + initial END char                            */
#define ENC_BUF_SIZE (2 * BUF_SIZE + 2)

/* 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, unsigned 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);
}

struct slip_proto {
	unsigned char ibuf[ENC_BUF_SIZE];
	unsigned char obuf[ENC_BUF_SIZE];
	int more; /* more data: do not read fd until ibuf has been drained */
	int pos;
	int esc;
};

static inline void slip_proto_init(struct slip_proto * slip)
{
	memset(slip->ibuf, 0, sizeof(slip->ibuf));
	memset(slip->obuf, 0, sizeof(slip->obuf));
	slip->more = 0;
	slip->pos = 0;
	slip->esc = 0;
}

extern int slip_proto_read(int fd, void *buf, int len,
			   struct slip_proto *slip);
extern int slip_proto_write(int fd, void *buf, int len,
			    struct slip_proto *slip);

#endif
Commit	Line	Data
a3c77c67 JD	1	#ifndef __UM_SLIP_COMMON_H
a3c77c67 JD	2	#define __UM_SLIP_COMMON_H
1da177e4	3
a3c77c67 JD	4	#define BUF_SIZE 1500
	5	/* two bytes each for a (pathological) max packet of escaped chars + *
	6	* terminating END char + initial END char */
	7	#define ENC_BUF_SIZE (2 * BUF_SIZE + 2)
1da177e4 LT	8
	9	/* SLIP protocol characters. */
	10	#define SLIP_END 0300 /* indicates end of frame */
	11	#define SLIP_ESC 0333 /* indicates byte stuffing */
	12	#define SLIP_ESC_END 0334 /* ESC ESC_END means END 'data' */
	13	#define SLIP_ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
	14
da00d9a5 JD	15	static inline int slip_unesc(unsigned char c, unsigned char buf, int pos,
da00d9a5 JD	16	int *esc)
1da177e4 LT	17	{
	18	int ret;
	19
	20	switch(c){
	21	case SLIP_END:
	22	*esc = 0;
	23	ret=*pos;
	24	*pos=0;
	25	return(ret);
	26	case SLIP_ESC:
	27	*esc = 1;
	28	return(0);
	29	case SLIP_ESC_ESC:
	30	if(*esc){
	31	*esc = 0;
	32	c = SLIP_ESC;
	33	}
	34	break;
	35	case SLIP_ESC_END:
	36	if(*esc){
	37	*esc = 0;
	38	c = SLIP_END;
	39	}
	40	break;
	41	}
	42	buf[(*pos)++] = c;
	43	return(0);
	44	}
	45
	46	static inline int slip_esc(unsigned char s, unsigned char d, int len)
	47	{
	48	unsigned char *ptr = d;
	49	unsigned char c;
	50
	51	/*
	52	* Send an initial END character to flush out any
	53	* data that may have accumulated in the receiver
	54	* due to line noise.
	55	*/
	56
	57	*ptr++ = SLIP_END;
	58
	59	/*
	60	* For each byte in the packet, send the appropriate
	61	* character sequence, according to the SLIP protocol.
	62	*/
	63
	64	while (len-- > 0) {
	65	switch(c = *s++) {
	66	case SLIP_END:
	67	*ptr++ = SLIP_ESC;
	68	*ptr++ = SLIP_ESC_END;
	69	break;
	70	case SLIP_ESC:
	71	*ptr++ = SLIP_ESC;
	72	*ptr++ = SLIP_ESC_ESC;
	73	break;
	74	default:
	75	*ptr++ = c;
	76	break;
	77	}
	78	}
	79	*ptr++ = SLIP_END;
	80	return (ptr - d);
81	}
82
a3c77c67 JD	83	struct slip_proto {
	84	unsigned char ibuf[ENC_BUF_SIZE];
	85	unsigned char obuf[ENC_BUF_SIZE];
	86	int more; /* more data: do not read fd until ibuf has been drained */
	87	int pos;
	88	int esc;
	89	};
	90
854e981c PBG	91	static inline void slip_proto_init(struct slip_proto * slip)
	92	{
	93	memset(slip->ibuf, 0, sizeof(slip->ibuf));
	94	memset(slip->obuf, 0, sizeof(slip->obuf));
	95	slip->more = 0;
	96	slip->pos = 0;
	97	slip->esc = 0;
a3c77c67	98	}
1da177e4	99
a3c77c67 JD	100	extern int slip_proto_read(int fd, void *buf, int len,
	101	struct slip_proto *slip);
	102	extern int slip_proto_write(int fd, void *buf, int len,
	103	struct slip_proto *slip);
	104
	105	#endif