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author | Jeff Garzik <jgarzik@pretzel.yyz.us> | 2005-06-26 17:11:03 -0400 |
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committer | Jeff Garzik <jgarzik@pobox.com> | 2005-06-26 17:11:03 -0400 |
commit | 8b0ee07e108b2eefdab5bb73f33223f18926c3b2 (patch) | |
tree | f68ca04180c5488301a40ec212ef2eb2467cf56c /arch/um/drivers/slip_common.h | |
parent | 4638aef40ba9ebb9734caeed1f373c24015259fd (diff) | |
parent | 8678887e7fb43cd6c9be6c9807b05e77848e0920 (diff) | |
download | linux-next-8b0ee07e108b2eefdab5bb73f33223f18926c3b2.tar.gz |
Merge upstream (approx. 2.6.12-git8) into 'janitor' branch of netdev-2.6.
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 000000000000..2ae76d8f1be1 --- /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 |