diff options
author | Jaroslav Kysela <perex@hera.kernel.org> | 2005-06-21 07:39:41 -0700 |
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committer | Jaroslav Kysela <perex@hera.kernel.org> | 2005-06-21 07:39:41 -0700 |
commit | fae6ec69c84d71b1d5bda9ede1a262c1681684aa (patch) | |
tree | eb4aff9a5c2b7d04ce09a3717bb1dd4a79fe7595 /arch/um/drivers/slip_common.h | |
parent | bbc0274e9bb2e3f1d724d445a2bd32566b9b66f7 (diff) | |
parent | 1d345dac1f30af1cd9f3a1faa12f9f18f17f236e (diff) |
Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git
Diffstat (limited to 'arch/um/drivers/slip_common.h')
-rw-r--r-- | arch/um/drivers/slip_common.h | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/um/drivers/slip_common.h b/arch/um/drivers/slip_common.h new file mode 100644 index 00000000000..2ae76d8f1be --- /dev/null +++ b/arch/um/drivers/slip_common.h @@ -0,0 +1,104 @@ +#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; +}; + +#define SLIP_PROTO_INIT { \ + .ibuf = { '\0' }, \ + .obuf = { '\0' }, \ + .more = 0, \ + .pos = 0, \ + .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 |