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path: root/drivers/isdn/i4l/isdnhdlc.c
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Diffstat (limited to 'drivers/isdn/i4l/isdnhdlc.c')
-rw-r--r--drivers/isdn/i4l/isdnhdlc.c617
1 files changed, 0 insertions, 617 deletions
diff --git a/drivers/isdn/i4l/isdnhdlc.c b/drivers/isdn/i4l/isdnhdlc.c
deleted file mode 100644
index 382a6b24e6a3..000000000000
--- a/drivers/isdn/i4l/isdnhdlc.c
+++ /dev/null
@@ -1,617 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * isdnhdlc.c -- General purpose ISDN HDLC decoder.
- *
- * Copyright (C)
- * 2009 Karsten Keil <keil@b1-systems.de>
- * 2002 Wolfgang Mües <wolfgang@iksw-muees.de>
- * 2001 Frode Isaksen <fisaksen@bewan.com>
- * 2001 Kai Germaschewski <kai.germaschewski@gmx.de>
- */
-
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/crc-ccitt.h>
-#include <linux/isdn/hdlc.h>
-#include <linux/bitrev.h>
-
-/*-------------------------------------------------------------------*/
-
-MODULE_AUTHOR("Wolfgang Mües <wolfgang@iksw-muees.de>, "
- "Frode Isaksen <fisaksen@bewan.com>, "
- "Kai Germaschewski <kai.germaschewski@gmx.de>");
-MODULE_DESCRIPTION("General purpose ISDN HDLC decoder");
-MODULE_LICENSE("GPL");
-
-/*-------------------------------------------------------------------*/
-
-enum {
- HDLC_FAST_IDLE, HDLC_GET_FLAG_B0, HDLC_GETFLAG_B1A6, HDLC_GETFLAG_B7,
- HDLC_GET_DATA, HDLC_FAST_FLAG
-};
-
-enum {
- HDLC_SEND_DATA, HDLC_SEND_CRC1, HDLC_SEND_FAST_FLAG,
- HDLC_SEND_FIRST_FLAG, HDLC_SEND_CRC2, HDLC_SEND_CLOSING_FLAG,
- HDLC_SEND_IDLE1, HDLC_SEND_FAST_IDLE, HDLC_SENDFLAG_B0,
- HDLC_SENDFLAG_B1A6, HDLC_SENDFLAG_B7, STOPPED, HDLC_SENDFLAG_ONE
-};
-
-void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features)
-{
- memset(hdlc, 0, sizeof(struct isdnhdlc_vars));
- hdlc->state = HDLC_GET_DATA;
- if (features & HDLC_56KBIT)
- hdlc->do_adapt56 = 1;
- if (features & HDLC_BITREVERSE)
- hdlc->do_bitreverse = 1;
-}
-EXPORT_SYMBOL(isdnhdlc_out_init);
-
-void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features)
-{
- memset(hdlc, 0, sizeof(struct isdnhdlc_vars));
- if (features & HDLC_DCHANNEL) {
- hdlc->dchannel = 1;
- hdlc->state = HDLC_SEND_FIRST_FLAG;
- } else {
- hdlc->dchannel = 0;
- hdlc->state = HDLC_SEND_FAST_FLAG;
- hdlc->ffvalue = 0x7e;
- }
- hdlc->cbin = 0x7e;
- if (features & HDLC_56KBIT) {
- hdlc->do_adapt56 = 1;
- hdlc->state = HDLC_SENDFLAG_B0;
- } else
- hdlc->data_bits = 8;
- if (features & HDLC_BITREVERSE)
- hdlc->do_bitreverse = 1;
-}
-EXPORT_SYMBOL(isdnhdlc_rcv_init);
-
-static int
-check_frame(struct isdnhdlc_vars *hdlc)
-{
- int status;
-
- if (hdlc->dstpos < 2) /* too small - framing error */
- status = -HDLC_FRAMING_ERROR;
- else if (hdlc->crc != 0xf0b8) /* crc error */
- status = -HDLC_CRC_ERROR;
- else {
- /* remove CRC */
- hdlc->dstpos -= 2;
- /* good frame */
- status = hdlc->dstpos;
- }
- return status;
-}
-
-/*
- isdnhdlc_decode - decodes HDLC frames from a transparent bit stream.
-
- The source buffer is scanned for valid HDLC frames looking for
- flags (01111110) to indicate the start of a frame. If the start of
- the frame is found, the bit stuffing is removed (0 after 5 1's).
- When a new flag is found, the complete frame has been received
- and the CRC is checked.
- If a valid frame is found, the function returns the frame length
- excluding the CRC with the bit HDLC_END_OF_FRAME set.
- If the beginning of a valid frame is found, the function returns
- the length.
- If a framing error is found (too many 1s and not a flag) the function
- returns the length with the bit HDLC_FRAMING_ERROR set.
- If a CRC error is found the function returns the length with the
- bit HDLC_CRC_ERROR set.
- If the frame length exceeds the destination buffer size, the function
- returns the length with the bit HDLC_LENGTH_ERROR set.
-
- src - source buffer
- slen - source buffer length
- count - number of bytes removed (decoded) from the source buffer
- dst _ destination buffer
- dsize - destination buffer size
- returns - number of decoded bytes in the destination buffer and status
- flag.
-*/
-int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, int slen,
- int *count, u8 *dst, int dsize)
-{
- int status = 0;
-
- static const unsigned char fast_flag[] = {
- 0x00, 0x00, 0x00, 0x20, 0x30, 0x38, 0x3c, 0x3e, 0x3f
- };
-
- static const unsigned char fast_flag_value[] = {
- 0x00, 0x7e, 0xfc, 0xf9, 0xf3, 0xe7, 0xcf, 0x9f, 0x3f
- };
-
- static const unsigned char fast_abort[] = {
- 0x00, 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
- };
-
-#define handle_fast_flag(h) \
- do { \
- if (h->cbin == fast_flag[h->bit_shift]) { \
- h->ffvalue = fast_flag_value[h->bit_shift]; \
- h->state = HDLC_FAST_FLAG; \
- h->ffbit_shift = h->bit_shift; \
- h->bit_shift = 1; \
- } else { \
- h->state = HDLC_GET_DATA; \
- h->data_received = 0; \
- } \
- } while (0)
-
-#define handle_abort(h) \
- do { \
- h->shift_reg = fast_abort[h->ffbit_shift - 1]; \
- h->hdlc_bits1 = h->ffbit_shift - 2; \
- if (h->hdlc_bits1 < 0) \
- h->hdlc_bits1 = 0; \
- h->data_bits = h->ffbit_shift - 1; \
- h->state = HDLC_GET_DATA; \
- h->data_received = 0; \
- } while (0)
-
- *count = slen;
-
- while (slen > 0) {
- if (hdlc->bit_shift == 0) {
- /* the code is for bitreverse streams */
- if (hdlc->do_bitreverse == 0)
- hdlc->cbin = bitrev8(*src++);
- else
- hdlc->cbin = *src++;
- slen--;
- hdlc->bit_shift = 8;
- if (hdlc->do_adapt56)
- hdlc->bit_shift--;
- }
-
- switch (hdlc->state) {
- case STOPPED:
- return 0;
- case HDLC_FAST_IDLE:
- if (hdlc->cbin == 0xff) {
- hdlc->bit_shift = 0;
- break;
- }
- hdlc->state = HDLC_GET_FLAG_B0;
- hdlc->hdlc_bits1 = 0;
- hdlc->bit_shift = 8;
- break;
- case HDLC_GET_FLAG_B0:
- if (!(hdlc->cbin & 0x80)) {
- hdlc->state = HDLC_GETFLAG_B1A6;
- hdlc->hdlc_bits1 = 0;
- } else {
- if ((!hdlc->do_adapt56) &&
- (++hdlc->hdlc_bits1 >= 8) &&
- (hdlc->bit_shift == 1))
- hdlc->state = HDLC_FAST_IDLE;
- }
- hdlc->cbin <<= 1;
- hdlc->bit_shift--;
- break;
- case HDLC_GETFLAG_B1A6:
- if (hdlc->cbin & 0x80) {
- hdlc->hdlc_bits1++;
- if (hdlc->hdlc_bits1 == 6)
- hdlc->state = HDLC_GETFLAG_B7;
- } else
- hdlc->hdlc_bits1 = 0;
- hdlc->cbin <<= 1;
- hdlc->bit_shift--;
- break;
- case HDLC_GETFLAG_B7:
- if (hdlc->cbin & 0x80) {
- hdlc->state = HDLC_GET_FLAG_B0;
- } else {
- hdlc->state = HDLC_GET_DATA;
- hdlc->crc = 0xffff;
- hdlc->shift_reg = 0;
- hdlc->hdlc_bits1 = 0;
- hdlc->data_bits = 0;
- hdlc->data_received = 0;
- }
- hdlc->cbin <<= 1;
- hdlc->bit_shift--;
- break;
- case HDLC_GET_DATA:
- if (hdlc->cbin & 0x80) {
- hdlc->hdlc_bits1++;
- switch (hdlc->hdlc_bits1) {
- case 6:
- break;
- case 7:
- if (hdlc->data_received)
- /* bad frame */
- status = -HDLC_FRAMING_ERROR;
- if (!hdlc->do_adapt56) {
- if (hdlc->cbin == fast_abort
- [hdlc->bit_shift + 1]) {
- hdlc->state =
- HDLC_FAST_IDLE;
- hdlc->bit_shift = 1;
- break;
- }
- } else
- hdlc->state = HDLC_GET_FLAG_B0;
- break;
- default:
- hdlc->shift_reg >>= 1;
- hdlc->shift_reg |= 0x80;
- hdlc->data_bits++;
- break;
- }
- } else {
- switch (hdlc->hdlc_bits1) {
- case 5:
- break;
- case 6:
- if (hdlc->data_received)
- status = check_frame(hdlc);
- hdlc->crc = 0xffff;
- hdlc->shift_reg = 0;
- hdlc->data_bits = 0;
- if (!hdlc->do_adapt56)
- handle_fast_flag(hdlc);
- else {
- hdlc->state = HDLC_GET_DATA;
- hdlc->data_received = 0;
- }
- break;
- default:
- hdlc->shift_reg >>= 1;
- hdlc->data_bits++;
- break;
- }
- hdlc->hdlc_bits1 = 0;
- }
- if (status) {
- hdlc->dstpos = 0;
- *count -= slen;
- hdlc->cbin <<= 1;
- hdlc->bit_shift--;
- return status;
- }
- if (hdlc->data_bits == 8) {
- hdlc->data_bits = 0;
- hdlc->data_received = 1;
- hdlc->crc = crc_ccitt_byte(hdlc->crc,
- hdlc->shift_reg);
-
- /* good byte received */
- if (hdlc->dstpos < dsize)
- dst[hdlc->dstpos++] = hdlc->shift_reg;
- else {
- /* frame too long */
- status = -HDLC_LENGTH_ERROR;
- hdlc->dstpos = 0;
- }
- }
- hdlc->cbin <<= 1;
- hdlc->bit_shift--;
- break;
- case HDLC_FAST_FLAG:
- if (hdlc->cbin == hdlc->ffvalue) {
- hdlc->bit_shift = 0;
- break;
- } else {
- if (hdlc->cbin == 0xff) {
- hdlc->state = HDLC_FAST_IDLE;
- hdlc->bit_shift = 0;
- } else if (hdlc->ffbit_shift == 8) {
- hdlc->state = HDLC_GETFLAG_B7;
- break;
- } else
- handle_abort(hdlc);
- }
- break;
- default:
- break;
- }
- }
- *count -= slen;
- return 0;
-}
-EXPORT_SYMBOL(isdnhdlc_decode);
-/*
- isdnhdlc_encode - encodes HDLC frames to a transparent bit stream.
-
- The bit stream starts with a beginning flag (01111110). After
- that each byte is added to the bit stream with bit stuffing added
- (0 after 5 1's).
- When the last byte has been removed from the source buffer, the
- CRC (2 bytes is added) and the frame terminates with the ending flag.
- For the dchannel, the idle character (all 1's) is also added at the end.
- If this function is called with empty source buffer (slen=0), flags or
- idle character will be generated.
-
- src - source buffer
- slen - source buffer length
- count - number of bytes removed (encoded) from source buffer
- dst _ destination buffer
- dsize - destination buffer size
- returns - number of encoded bytes in the destination buffer
-*/
-int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
- int *count, u8 *dst, int dsize)
-{
- static const unsigned char xfast_flag_value[] = {
- 0x7e, 0x3f, 0x9f, 0xcf, 0xe7, 0xf3, 0xf9, 0xfc, 0x7e
- };
-
- int len = 0;
-
- *count = slen;
-
- /* special handling for one byte frames */
- if ((slen == 1) && (hdlc->state == HDLC_SEND_FAST_FLAG))
- hdlc->state = HDLC_SENDFLAG_ONE;
- while (dsize > 0) {
- if (hdlc->bit_shift == 0) {
- if (slen && !hdlc->do_closing) {
- hdlc->shift_reg = *src++;
- slen--;
- if (slen == 0)
- /* closing sequence, CRC + flag(s) */
- hdlc->do_closing = 1;
- hdlc->bit_shift = 8;
- } else {
- if (hdlc->state == HDLC_SEND_DATA) {
- if (hdlc->data_received) {
- hdlc->state = HDLC_SEND_CRC1;
- hdlc->crc ^= 0xffff;
- hdlc->bit_shift = 8;
- hdlc->shift_reg =
- hdlc->crc & 0xff;
- } else if (!hdlc->do_adapt56)
- hdlc->state =
- HDLC_SEND_FAST_FLAG;
- else
- hdlc->state =
- HDLC_SENDFLAG_B0;
- }
-
- }
- }
-
- switch (hdlc->state) {
- case STOPPED:
- while (dsize--)
- *dst++ = 0xff;
- return dsize;
- case HDLC_SEND_FAST_FLAG:
- hdlc->do_closing = 0;
- if (slen == 0) {
- /* the code is for bitreverse streams */
- if (hdlc->do_bitreverse == 0)
- *dst++ = bitrev8(hdlc->ffvalue);
- else
- *dst++ = hdlc->ffvalue;
- len++;
- dsize--;
- break;
- }
- /* fall through */
- case HDLC_SENDFLAG_ONE:
- if (hdlc->bit_shift == 8) {
- hdlc->cbin = hdlc->ffvalue >>
- (8 - hdlc->data_bits);
- hdlc->state = HDLC_SEND_DATA;
- hdlc->crc = 0xffff;
- hdlc->hdlc_bits1 = 0;
- hdlc->data_received = 1;
- }
- break;
- case HDLC_SENDFLAG_B0:
- hdlc->do_closing = 0;
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- hdlc->hdlc_bits1 = 0;
- hdlc->state = HDLC_SENDFLAG_B1A6;
- break;
- case HDLC_SENDFLAG_B1A6:
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- hdlc->cbin++;
- if (++hdlc->hdlc_bits1 == 6)
- hdlc->state = HDLC_SENDFLAG_B7;
- break;
- case HDLC_SENDFLAG_B7:
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- if (slen == 0) {
- hdlc->state = HDLC_SENDFLAG_B0;
- break;
- }
- if (hdlc->bit_shift == 8) {
- hdlc->state = HDLC_SEND_DATA;
- hdlc->crc = 0xffff;
- hdlc->hdlc_bits1 = 0;
- hdlc->data_received = 1;
- }
- break;
- case HDLC_SEND_FIRST_FLAG:
- hdlc->data_received = 1;
- if (hdlc->data_bits == 8) {
- hdlc->state = HDLC_SEND_DATA;
- hdlc->crc = 0xffff;
- hdlc->hdlc_bits1 = 0;
- break;
- }
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- if (hdlc->shift_reg & 0x01)
- hdlc->cbin++;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- if (hdlc->bit_shift == 0) {
- hdlc->state = HDLC_SEND_DATA;
- hdlc->crc = 0xffff;
- hdlc->hdlc_bits1 = 0;
- }
- break;
- case HDLC_SEND_DATA:
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- if (hdlc->hdlc_bits1 == 5) {
- hdlc->hdlc_bits1 = 0;
- break;
- }
- if (hdlc->bit_shift == 8)
- hdlc->crc = crc_ccitt_byte(hdlc->crc,
- hdlc->shift_reg);
- if (hdlc->shift_reg & 0x01) {
- hdlc->hdlc_bits1++;
- hdlc->cbin++;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- } else {
- hdlc->hdlc_bits1 = 0;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- }
- break;
- case HDLC_SEND_CRC1:
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- if (hdlc->hdlc_bits1 == 5) {
- hdlc->hdlc_bits1 = 0;
- break;
- }
- if (hdlc->shift_reg & 0x01) {
- hdlc->hdlc_bits1++;
- hdlc->cbin++;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- } else {
- hdlc->hdlc_bits1 = 0;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- }
- if (hdlc->bit_shift == 0) {
- hdlc->shift_reg = (hdlc->crc >> 8);
- hdlc->state = HDLC_SEND_CRC2;
- hdlc->bit_shift = 8;
- }
- break;
- case HDLC_SEND_CRC2:
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- if (hdlc->hdlc_bits1 == 5) {
- hdlc->hdlc_bits1 = 0;
- break;
- }
- if (hdlc->shift_reg & 0x01) {
- hdlc->hdlc_bits1++;
- hdlc->cbin++;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- } else {
- hdlc->hdlc_bits1 = 0;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- }
- if (hdlc->bit_shift == 0) {
- hdlc->shift_reg = 0x7e;
- hdlc->state = HDLC_SEND_CLOSING_FLAG;
- hdlc->bit_shift = 8;
- }
- break;
- case HDLC_SEND_CLOSING_FLAG:
- hdlc->cbin <<= 1;
- hdlc->data_bits++;
- if (hdlc->hdlc_bits1 == 5) {
- hdlc->hdlc_bits1 = 0;
- break;
- }
- if (hdlc->shift_reg & 0x01)
- hdlc->cbin++;
- hdlc->shift_reg >>= 1;
- hdlc->bit_shift--;
- if (hdlc->bit_shift == 0) {
- hdlc->ffvalue =
- xfast_flag_value[hdlc->data_bits];
- if (hdlc->dchannel) {
- hdlc->ffvalue = 0x7e;
- hdlc->state = HDLC_SEND_IDLE1;
- hdlc->bit_shift = 8-hdlc->data_bits;
- if (hdlc->bit_shift == 0)
- hdlc->state =
- HDLC_SEND_FAST_IDLE;
- } else {
- if (!hdlc->do_adapt56) {
- hdlc->state =
- HDLC_SEND_FAST_FLAG;
- hdlc->data_received = 0;
- } else {
- hdlc->state = HDLC_SENDFLAG_B0;
- hdlc->data_received = 0;
- }
- /* Finished this frame, send flags */
- if (dsize > 1)
- dsize = 1;
- }
- }
- break;
- case HDLC_SEND_IDLE1:
- hdlc->do_closing = 0;
- hdlc->cbin <<= 1;
- hdlc->cbin++;
- hdlc->data_bits++;
- hdlc->bit_shift--;
- if (hdlc->bit_shift == 0) {
- hdlc->state = HDLC_SEND_FAST_IDLE;
- hdlc->bit_shift = 0;
- }
- break;
- case HDLC_SEND_FAST_IDLE:
- hdlc->do_closing = 0;
- hdlc->cbin = 0xff;
- hdlc->data_bits = 8;
- if (hdlc->bit_shift == 8) {
- hdlc->cbin = 0x7e;
- hdlc->state = HDLC_SEND_FIRST_FLAG;
- } else {
- /* the code is for bitreverse streams */
- if (hdlc->do_bitreverse == 0)
- *dst++ = bitrev8(hdlc->cbin);
- else
- *dst++ = hdlc->cbin;
- hdlc->bit_shift = 0;
- hdlc->data_bits = 0;
- len++;
- dsize = 0;
- }
- break;
- default:
- break;
- }
- if (hdlc->do_adapt56) {
- if (hdlc->data_bits == 7) {
- hdlc->cbin <<= 1;
- hdlc->cbin++;
- hdlc->data_bits++;
- }
- }
- if (hdlc->data_bits == 8) {
- /* the code is for bitreverse streams */
- if (hdlc->do_bitreverse == 0)
- *dst++ = bitrev8(hdlc->cbin);
- else
- *dst++ = hdlc->cbin;
- hdlc->data_bits = 0;
- len++;
- dsize--;
- }
- }
- *count -= slen;
-
- return len;
-}
-EXPORT_SYMBOL(isdnhdlc_encode);
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-29 11:17:36 +0000