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1#ifndef __UM_SLIP_COMMON_H
2#define __UM_SLIP_COMMON_H
3
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)
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
15static inline int slip_unesc(unsigned char c, unsigned char *buf, int *pos,
16 int *esc)
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
46static 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
83struct 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
91static 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;
98}
99
100extern int slip_proto_read(int fd, void *buf, int len,
101 struct slip_proto *slip);
102extern int slip_proto_write(int fd, void *buf, int len,
103 struct slip_proto *slip);
104
105#endif
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __UM_SLIP_COMMON_H
3#define __UM_SLIP_COMMON_H
4
5#define BUF_SIZE 1500
6 /* two bytes each for a (pathological) max packet of escaped chars + *
7 * terminating END char + initial END char */
8#define ENC_BUF_SIZE (2 * BUF_SIZE + 2)
9
10/* SLIP protocol characters. */
11#define SLIP_END 0300 /* indicates end of frame */
12#define SLIP_ESC 0333 /* indicates byte stuffing */
13#define SLIP_ESC_END 0334 /* ESC ESC_END means END 'data' */
14#define SLIP_ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
15
16static inline int slip_unesc(unsigned char c, unsigned char *buf, int *pos,
17 int *esc)
18{
19 int ret;
20
21 switch(c){
22 case SLIP_END:
23 *esc = 0;
24 ret=*pos;
25 *pos=0;
26 return(ret);
27 case SLIP_ESC:
28 *esc = 1;
29 return(0);
30 case SLIP_ESC_ESC:
31 if(*esc){
32 *esc = 0;
33 c = SLIP_ESC;
34 }
35 break;
36 case SLIP_ESC_END:
37 if(*esc){
38 *esc = 0;
39 c = SLIP_END;
40 }
41 break;
42 }
43 buf[(*pos)++] = c;
44 return(0);
45}
46
47static inline int slip_esc(unsigned char *s, unsigned char *d, int len)
48{
49 unsigned char *ptr = d;
50 unsigned char c;
51
52 /*
53 * Send an initial END character to flush out any
54 * data that may have accumulated in the receiver
55 * due to line noise.
56 */
57
58 *ptr++ = SLIP_END;
59
60 /*
61 * For each byte in the packet, send the appropriate
62 * character sequence, according to the SLIP protocol.
63 */
64
65 while (len-- > 0) {
66 switch(c = *s++) {
67 case SLIP_END:
68 *ptr++ = SLIP_ESC;
69 *ptr++ = SLIP_ESC_END;
70 break;
71 case SLIP_ESC:
72 *ptr++ = SLIP_ESC;
73 *ptr++ = SLIP_ESC_ESC;
74 break;
75 default:
76 *ptr++ = c;
77 break;
78 }
79 }
80 *ptr++ = SLIP_END;
81 return (ptr - d);
82}
83
84struct slip_proto {
85 unsigned char ibuf[ENC_BUF_SIZE];
86 unsigned char obuf[ENC_BUF_SIZE];
87 int more; /* more data: do not read fd until ibuf has been drained */
88 int pos;
89 int esc;
90};
91
92static inline void slip_proto_init(struct slip_proto * slip)
93{
94 memset(slip->ibuf, 0, sizeof(slip->ibuf));
95 memset(slip->obuf, 0, sizeof(slip->obuf));
96 slip->more = 0;
97 slip->pos = 0;
98 slip->esc = 0;
99}
100
101extern int slip_proto_read(int fd, void *buf, int len,
102 struct slip_proto *slip);
103extern int slip_proto_write(int fd, void *buf, int len,
104 struct slip_proto *slip);
105
106#endif