patch-2.4.21 linux-2.4.21/drivers/isdn/hisax/rawhdlc.c
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- Lines: 544
- Date:
1969-12-31 16:00:00.000000000 -0800
- Orig file:
linux-2.4.20/drivers/isdn/hisax/rawhdlc.c
- Orig date:
2001-12-21 09:41:54.000000000 -0800
diff -urN linux-2.4.20/drivers/isdn/hisax/rawhdlc.c linux-2.4.21/drivers/isdn/hisax/rawhdlc.c
@@ -1,543 +0,0 @@
-/* $Id: rawhdlc.c,v 1.1.4.1 2001/11/20 14:19:36 kai Exp $
- *
- * support routines for cards that don't support HDLC
- *
- * Author Brent Baccala
- * Copyright by Karsten Keil <keil@isdn4linux.de>
- * by Brent Baccala <baccala@FreeSoft.org>
- *
- * This software may be used and distributed according to the terms
- * of the GNU General Public License, incorporated herein by reference.
- *
- *
- * Some passive ISDN cards, such as the Traverse NETJet and the AMD 7930,
- * don't perform HDLC encapsulation over the B channel. Drivers for
- * such cards use support routines in this file to perform B channel HDLC.
- *
- * Bit-synchronous HDLC encapsulation is a means of encapsulating packets
- * over a continuously transmitting serial communications link.
- * It looks like this:
- *
- * 11111111101111110...........0111111011111111111
- * iiiiiiiiiffffffffdddddddddddffffffffiiiiiiiiiii
- *
- * i = idle f = flag d = data
- *
- * When idle, the channel sends a continuous string of ones (mark
- * idle; illustrated), or a continuous string of flag characters (flag
- * idle). The beginning of a data frame is marked by a flag character
- * (01111110), then comes the actual data, followed by another flag
- * character, after which another frame may be sent immediately (a
- * single flag may serve as both the end of one frame and the start of
- * the next), or the link may return to idle. Obviously, the flag
- * character can not appear anywhere in the data (or a false
- * end-of-frame would occur), so the transmitter performs
- * "bit-stuffing" - inserting a zero bit after every five one bits,
- * irregardless of the original bit after the five ones. Byte
- * ordering is irrelevent at this point - the data is treated as a
- * string of bits, not bytes. Since no more than 5 ones may now occur
- * in a row, the flag sequence, with its 6 ones, is unique.
- *
- * Upon reception, a zero bit that occur after 5 one bits is simply
- * discarded. A series of 6 one bits is end-of-frame, and a series of
- * 7 one bits is an abort. Once bit-stuffing has been corrected for,
- * an integer number of bytes should now be present. The last two
- * of these bytes form the Frame Check Sequence, a CRC that is verified
- * and then discarded. Note that bit-stuffing is performed on the FCS
- * just as if it were regular data.
- *
- *
- *
- * int make_raw_hdlc_data(u_char *src, u_int slen,
- * u_char *dst, u_int dsize)
- *
- * Used for transmission. Copies slen bytes from src to dst, performing
- * HDLC encapsulation (flag bytes, bit-stuffing, CRC) in the process.
- * dsize is size of destination buffer, and should be at least
- * ((6*slen)/5)+5 bytes to ensure adequate space will be available.
- * Function returns length (in bytes) of valid destination buffer, or
- * 0 upon destination overflow.
- *
- * void init_hdlc_state(struct hdlc_state *stateptr, int mode)
- *
- * Initializes hdlc_state structure before first call to read_raw_hdlc_data
- *
- * mode = 0: Sane mode
- * mode = 1/2:
- * Insane mode; NETJet use a shared unsigned int memory block (
- * with busmaster DMA), the bit pattern of every word is
- * <8 B1> <8 B2> <8 Mon> <2 D> <4 C/I> <MX> <MR>
- * according to Siemens IOM-2 interface, so we have to handle
- * the src buffer as unsigned int and have to shift/mask the
- * B-channel bytes.
- * mode 1 -> B1 mode 2 -> B2 data is used
- *
- * int read_raw_hdlc_data(struct hdlc_state *saved_state,
- * u_char *src, u_int slen,
- * u_char *dst, u_int dsize)
- *
- * Used for reception. Scans source buffer bit-by-bit looking for
- * valid HDLC frames, which are copied to destination buffer. HDLC
- * state information is stored in a structure, which allows this
- * function to process frames spread across several blocks of raw
- * HDLC data. Part of the state information is bit offsets into
- * the source and destination buffers.
- *
- * A return value >0 indicates the length of a valid frame, now
- * stored in the destination buffer. In this case, the source
- * buffer might not be completely processed, so this function should
- * be called again with the same source buffer, possibly with a
- * different destination buffer.
- *
- * A return value of zero indicates that the source buffer was
- * completely processed without finding a valid end-of-packet;
- * however, we might be in the middle of packet reception, so
- * the function should be called again with the next block of
- * raw HDLC data and the same destination buffer. It is NOT
- * permitted to change the destination buffer in this case,
- * since data may already have begun to be stored there.
- *
- * A return value of -1 indicates some kind of error - destination
- * buffer overflow, CRC check failed, frame not a multiple of 8
- * bits. Destination buffer probably contains invalid data, which
- * should be discarded. Call function again with same source buffer
- * and a new (or same) destination buffer.
- *
- * Suggested calling sequence:
- *
- * init_hdlc_state(...);
- * for (EACH_RAW_DATA_BLOCK) {
- * while (len = read_raw_hdlc_data(...)) {
- * if (len == -1) DISCARD_FRAME;
- * else PROCESS_FRAME;
- * }
- * }
- *
- *
- * Test the code in this file as follows:
- * gcc -DDEBUGME -o rawhdlctest rawhdlc.c
- * ./rawhdlctest < rawdata
- *
- * The file "rawdata" can be easily generated from a HISAX B-channel
- * hex dump (CF CF CF 02 ...) using the following perl script:
- *
- * while(<>) {
- * @hexlist = split ' ';
- * while ($hexstr = shift(@hexlist)) {
- * printf "%c", hex($hexstr);
- * }
- * }
- *
- */
-
-#ifdef DEBUGME
-#include <stdio.h>
-#endif
-
-#include <linux/types.h>
-#include <linux/ppp_defs.h>
-#include "rawhdlc.h"
-
-/* There's actually an identical copy of this table in the PPP code
- * (ppp_crc16_table), but I don't want this code dependent on PPP
- */
-
-// static
-__u16 fcstab[256] =
-{
- 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
- 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
- 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
- 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
- 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
- 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
- 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
- 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
- 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
- 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
- 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
- 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
- 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
- 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
- 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
- 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
- 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
- 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
- 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
- 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
- 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
- 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
- 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
- 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
- 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
- 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
- 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
- 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
- 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
- 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
- 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
- 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
-};
-
-#define HDLC_ZERO_SEARCH 0
-#define HDLC_FLAG_SEARCH 1
-#define HDLC_FLAG_FOUND 2
-#define HDLC_FRAME_FOUND 3
-#define HDLC_NULL 4
-#define HDLC_PART 5
-#define HDLC_FULL 6
-
-#define HDLC_FLAG_VALUE 0x7e
-
-
-#define MAKE_RAW_BYTE for (j=0; j<8; j++) { \
- bitcnt++;\
- out_val >>= 1;\
- if (val & 1) {\
- s_one++;\
- out_val |= 0x80;\
- } else {\
- s_one = 0;\
- out_val &= 0x7f;\
- }\
- if (bitcnt==8) {\
- if (d_cnt == dsize) return 0;\
- dst[d_cnt++] = out_val;\
- bitcnt = 0;\
- }\
- if (s_one == 5) {\
- out_val >>= 1;\
- out_val &= 0x7f;\
- bitcnt++;\
- s_one = 0;\
- }\
- if (bitcnt==8) {\
- if (d_cnt == dsize) return 0;\
- dst[d_cnt++] = out_val;\
- bitcnt = 0;\
- }\
- val >>= 1;\
- }
-
-/* Optimization suggestion: If needed, this function could be
- * dramatically sped up using a state machine. Each state would
- * correspond to having seen N one bits, and being offset M bits into
- * the current output byte. N ranges from 0 to 4, M from 0 to 7, so
- * we need 5*8 = 35 states. Each state would have a table with 256
- * entries, one for each input character. Each entry would contain
- * three output characters, an output state, an a byte increment
- * that's either 1 or 2. All this could fit in four bytes; so we need
- * 4 bytes * 256 characters = 1 KB for each state (35 KB total). Zero
- * the output buffer before you start. For each character in your
- * input, you look it up in the current state's table and get three
- * bytes to be or'ed into the output at the current byte offset, and
- * an byte increment to move your pointer forward. A simple Perl
- * script could generate the tables. Given HDLC semantics, probably
- * would be better to set output to all 1s, then use ands instead of ors.
- * A smaller state machine could operate on nibbles instead of bytes.
- * A state machine for 32-bit architectures could use word offsets
- * instead of byte offsets, requiring 5*32 = 160 states; probably
- * best to work on nibbles in such a case.
- */
-
-
-int make_raw_hdlc_data(u_char *src, u_int slen, u_char *dst, u_int dsize)
-{
- register u_int i,d_cnt=0;
- register u_char j;
- register u_char val;
- register u_char s_one = 0;
- register u_char out_val = 0;
- register u_char bitcnt = 0;
- u_int fcs;
-
-
- dst[d_cnt++] = HDLC_FLAG_VALUE;
- fcs = PPP_INITFCS;
- for (i=0; i<slen; i++) {
- val = src[i];
- fcs = PPP_FCS (fcs, val);
- MAKE_RAW_BYTE;
- }
- fcs ^= 0xffff;
- val = fcs & 0xff;
- MAKE_RAW_BYTE;
- val = (fcs>>8) & 0xff;
- MAKE_RAW_BYTE;
- val = HDLC_FLAG_VALUE;
- for (j=0; j<8; j++) {
- bitcnt++;
- out_val >>= 1;
- if (val & 1)
- out_val |= 0x80;
- else
- out_val &= 0x7f;
- if (bitcnt==8) {
- if (d_cnt == dsize) return 0;
- dst[d_cnt++] = out_val;
- bitcnt = 0;
- }
- val >>= 1;
- }
- if (bitcnt) {
- while (8>bitcnt++) {
- out_val >>= 1;
- out_val |= 0x80;
- }
- if (d_cnt == dsize) return 0;
- dst[d_cnt++] = out_val;
- }
-
- return d_cnt;
-}
-
-void init_hdlc_state(struct hdlc_state *stateptr, int mode)
-{
- stateptr->state = HDLC_ZERO_SEARCH;
- stateptr->r_one = 0;
- stateptr->r_val = 0;
- stateptr->o_bitcnt = 0;
- stateptr->i_bitcnt = 0;
- stateptr->insane_mode = mode;
-}
-
-/* Optimization suggestion: A similar state machine could surely
- * be developed for this function as well.
- */
-
-int read_raw_hdlc_data(struct hdlc_state *saved_state,
- u_char *src, u_int slen, u_char *dst, u_int dsize)
-{
- int retval=0;
- register u_char val;
- register u_char state = saved_state->state;
- register u_char r_one = saved_state->r_one;
- register u_char r_val = saved_state->r_val;
- register u_int o_bitcnt = saved_state->o_bitcnt;
- register u_int i_bitcnt = saved_state->i_bitcnt;
- register u_int fcs = saved_state->fcs;
- register u_int *isrc = (u_int *) src;
-
- /* Use i_bitcnt (bit offset into source buffer) to reload "val"
- * in case we're starting up again partway through a source buffer
- */
-
- if ((i_bitcnt >> 3) < slen) {
- if (saved_state->insane_mode==1) {
- val = isrc[(i_bitcnt >> 3)] & 0xff;
- } else if (saved_state->insane_mode==2) {
- val = (isrc[i_bitcnt >> 3] >>8) & 0xff;
- } else {
- val = src[i_bitcnt >> 3];
- }
- val >>= i_bitcnt & 7;
- }
-
- /* One bit per loop. Keep going until we've got something to
- * report (retval != 0), or we exhaust the source buffer
- */
-
- while ((retval == 0) && ((i_bitcnt >> 3) < slen)) {
- if ((i_bitcnt & 7) == 0) {
- if (saved_state->insane_mode==1) {
- val = isrc[(i_bitcnt >> 3)] & 0xff;
- } else if (saved_state->insane_mode==2) {
- val = (isrc[i_bitcnt >> 3] >>8) & 0xff;
- } else {
- val = src[i_bitcnt >> 3];
- }
-#ifdef DEBUGME
- printf("Input byte %d: 0x%2x\n", i_bitcnt>>3, val);
-#endif
- if (val == 0xff) {
- state = HDLC_ZERO_SEARCH;
- o_bitcnt = 0;
- r_one = 0;
- i_bitcnt += 8;
- continue;
- }
- }
-
-#ifdef DEBUGME
- /* printf("Data bit=%d (%d/%d)\n", val&1, i_bitcnt>>3, i_bitcnt&7);*/
-#endif
-
- if (state == HDLC_ZERO_SEARCH) {
- if (val & 1) {
- r_one++;
- } else {
- r_one=0;
- state= HDLC_FLAG_SEARCH;
- }
- } else if (state == HDLC_FLAG_SEARCH) {
- if (val & 1) {
- r_one++;
- if (r_one>6) {
- state=HDLC_ZERO_SEARCH;
- }
- } else {
- if (r_one==6) {
- o_bitcnt=0;
- r_val=0;
- state=HDLC_FLAG_FOUND;
- }
- r_one=0;
- }
- } else if (state == HDLC_FLAG_FOUND) {
- if (val & 1) {
- r_one++;
- if (r_one>6) {
- state=HDLC_ZERO_SEARCH;
- } else {
- r_val >>= 1;
- r_val |= 0x80;
- o_bitcnt++;
- }
- } else {
- if (r_one==6) {
- o_bitcnt=0;
- r_val=0;
- r_one=0;
- i_bitcnt++;
- val >>= 1;
- continue;
- } else if (r_one!=5) {
- r_val >>= 1;
- r_val &= 0x7f;
- o_bitcnt++;
- }
- r_one=0;
- }
- if ((state != HDLC_ZERO_SEARCH) &&
- !(o_bitcnt & 7)) {
-#ifdef DEBUGME
- printf("HDLC_FRAME_FOUND at i_bitcnt:%d\n",i_bitcnt);
-#endif
- state=HDLC_FRAME_FOUND;
- fcs = PPP_INITFCS;
- dst[0] = r_val;
- fcs = PPP_FCS (fcs, r_val);
- }
- } else if (state == HDLC_FRAME_FOUND) {
- if (val & 1) {
- r_one++;
- if (r_one>6) {
- state=HDLC_ZERO_SEARCH;
- o_bitcnt=0;
- } else {
- r_val >>= 1;
- r_val |= 0x80;
- o_bitcnt++;
- }
- } else {
- if (r_one==6) {
- r_val=0;
- r_one=0;
- o_bitcnt++;
- if (o_bitcnt & 7) {
- /* Alignment error */
-#ifdef DEBUGME
- printf("Alignment error\n");
-#endif
- state=HDLC_FLAG_SEARCH;
- retval = -1;
- } else if (fcs==PPP_GOODFCS) {
- /* Valid frame */
- state=HDLC_FLAG_FOUND;
- retval = (o_bitcnt>>3)-3;
- } else {
- /* CRC error */
-#ifdef DEBUGME
- printf("CRC error; fcs was 0x%x, should have been 0x%x\n", fcs, PPP_GOODFCS);
-#endif
- state=HDLC_FLAG_FOUND;
- retval = -1;
- }
- } else if (r_one==5) {
- r_one=0;
- i_bitcnt++;
- val >>= 1;
- continue;
- } else {
- r_val >>= 1;
- r_val &= 0x7f;
- o_bitcnt++;
- }
- r_one=0;
- }
- if ((state == HDLC_FRAME_FOUND) &&
- !(o_bitcnt & 7)) {
- if ((o_bitcnt>>3)>=dsize) {
- /* Buffer overflow error */
-#ifdef DEBUGME
- printf("Buffer overflow error\n");
-#endif
- r_val=0;
- state=HDLC_FLAG_SEARCH;
- retval = -1;
- } else {
- dst[(o_bitcnt>>3)-1] = r_val;
- fcs = PPP_FCS (fcs, r_val);
-#ifdef DEBUGME
- printf("Output byte %d: 0x%02x; FCS 0x%04x\n", (o_bitcnt>>3)-1, r_val, fcs);
-#endif
- }
- }
- }
- i_bitcnt ++;
- val >>= 1;
- }
-
- /* We exhausted the source buffer before anything else happened
- * (retval==0). Reset i_bitcnt in expectation of a new source
- * buffer. Other, we either had an error or a valid frame, so
- * reset o_bitcnt in expectation of a new destination buffer.
- */
-
- if (retval == 0) {
- i_bitcnt = 0;
- } else {
- o_bitcnt = 0;
- }
-
- saved_state->state = state;
- saved_state->r_one = r_one;
- saved_state->r_val = r_val;
- saved_state->fcs = fcs;
- saved_state->o_bitcnt = o_bitcnt;
- saved_state->i_bitcnt = i_bitcnt;
-
- return (retval);
-}
-
-
-
-#ifdef DEBUGME
-
-char buffer[1024];
-char obuffer[1024];
-
-main()
-{
- int buflen=0;
- int len;
- struct hdlc_state hdlc_state;
-
- while((buffer[buflen] = getc(stdin)) != EOF && buflen<1024) buflen++;
-
- printf("buflen = %d\n", buflen);
-
- init_hdlc_state(&hdlc_state, 0);
-
- while (len = read_raw_hdlc_data(&hdlc_state,buffer,buflen,obuffer,1024)) {
- if (len == -1) printf("Error @ byte %d/bit %d\n",
- hdlc_state.i_bitcnt>>3, hdlc_state.i_bitcnt & 7);
- else {
- printf("Frame received: len %d\n", len);
- }
- }
-
- printf("Done\n");
-}
-
-#endif
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