]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) | |
3 | * Licensed under the GPL | |
4 | */ | |
5 | ||
6 | #ifndef __UM_SLIP_PROTO_H__ | |
7 | #define __UM_SLIP_PROTO_H__ | |
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 | ||
15 | static inline int slip_unesc(unsigned char c,char *buf,int *pos, int *esc) | |
16 | { | |
17 | int ret; | |
18 | ||
19 | switch(c){ | |
20 | case SLIP_END: | |
21 | *esc = 0; | |
22 | ret=*pos; | |
23 | *pos=0; | |
24 | return(ret); | |
25 | case SLIP_ESC: | |
26 | *esc = 1; | |
27 | return(0); | |
28 | case SLIP_ESC_ESC: | |
29 | if(*esc){ | |
30 | *esc = 0; | |
31 | c = SLIP_ESC; | |
32 | } | |
33 | break; | |
34 | case SLIP_ESC_END: | |
35 | if(*esc){ | |
36 | *esc = 0; | |
37 | c = SLIP_END; | |
38 | } | |
39 | break; | |
40 | } | |
41 | buf[(*pos)++] = c; | |
42 | return(0); | |
43 | } | |
44 | ||
45 | static inline int slip_esc(unsigned char *s, unsigned char *d, int len) | |
46 | { | |
47 | unsigned char *ptr = d; | |
48 | unsigned char c; | |
49 | ||
50 | /* | |
51 | * Send an initial END character to flush out any | |
52 | * data that may have accumulated in the receiver | |
53 | * due to line noise. | |
54 | */ | |
55 | ||
56 | *ptr++ = SLIP_END; | |
57 | ||
58 | /* | |
59 | * For each byte in the packet, send the appropriate | |
60 | * character sequence, according to the SLIP protocol. | |
61 | */ | |
62 | ||
63 | while (len-- > 0) { | |
64 | switch(c = *s++) { | |
65 | case SLIP_END: | |
66 | *ptr++ = SLIP_ESC; | |
67 | *ptr++ = SLIP_ESC_END; | |
68 | break; | |
69 | case SLIP_ESC: | |
70 | *ptr++ = SLIP_ESC; | |
71 | *ptr++ = SLIP_ESC_ESC; | |
72 | break; | |
73 | default: | |
74 | *ptr++ = c; | |
75 | break; | |
76 | } | |
77 | } | |
78 | *ptr++ = SLIP_END; | |
79 | return (ptr - d); | |
80 | } | |
81 | ||
82 | #endif | |
83 | ||
84 | /* | |
85 | * Overrides for Emacs so that we follow Linus's tabbing style. | |
86 | * Emacs will notice this stuff at the end of the file and automatically | |
87 | * adjust the settings for this buffer only. This must remain at the end | |
88 | * of the file. | |
89 | * --------------------------------------------------------------------------- | |
90 | * Local variables: | |
91 | * c-file-style: "linux" | |
92 | * End: | |
93 | */ |