isdn_v110.c
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上传日期:2013-02-24
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- /* $Id: isdn_v110.c,v 1.1.4.1 2001/11/20 14:19:34 kai Exp $
- *
- * Linux ISDN subsystem, V.110 related functions (linklevel).
- *
- * Copyright by Thomas Pfeiffer (pfeiffer@pds.de)
- *
- * This software may be used and distributed according to the terms
- * of the GNU General Public License, incorporated herein by reference.
- *
- */
- #include <linux/string.h>
- #include <linux/kernel.h>
- #include <linux/slab.h>
- #include <linux/mm.h>
- #include <linux/isdn.h>
- #include "isdn_v110.h"
- #undef ISDN_V110_DEBUG
- char *isdn_v110_revision = "$Revision: 1.1.4.1 $";
- #define V110_38400 255
- #define V110_19200 15
- #define V110_9600 3
- /*
- * The following data are precoded matrices, online and offline matrix
- * for 9600, 19200 und 38400, respectively
- */
- static unsigned char V110_OnMatrix_9600[] =
- {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
- 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd,
- 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
- 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd};
- static unsigned char V110_OffMatrix_9600[] =
- {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
- static unsigned char V110_OnMatrix_19200[] =
- {0xf0, 0xf0, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7,
- 0xfd, 0xff, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7};
- static unsigned char V110_OffMatrix_19200[] =
- {0xf0, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
- static unsigned char V110_OnMatrix_38400[] =
- {0x00, 0x7f, 0x7f, 0x7f, 0x7f, 0xfd, 0x7f, 0x7f, 0x7f, 0x7f};
- static unsigned char V110_OffMatrix_38400[] =
- {0x00, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff};
- /*
- * FlipBits reorders sequences of keylen bits in one byte.
- * E.g. source order 7654321 will be converted to 45670123 when keylen = 4,
- * and to 67452301 when keylen = 2. This is necessary because ordering on
- * the isdn line is the other way.
- */
- static __inline unsigned char
- FlipBits(unsigned char c, int keylen)
- {
- unsigned char b = c;
- unsigned char bit = 128;
- int i;
- int j;
- int hunks = (8 / keylen);
- c = 0;
- for (i = 0; i < hunks; i++) {
- for (j = 0; j < keylen; j++) {
- if (b & (bit >> j))
- c |= bit >> (keylen - j - 1);
- }
- bit >>= keylen;
- }
- return c;
- }
- /* isdn_v110_open allocates and initializes private V.110 data
- * structures and returns a pointer to these.
- */
- static isdn_v110_stream *
- isdn_v110_open(unsigned char key, int hdrlen, int maxsize)
- {
- int i;
- isdn_v110_stream *v;
- if ((v = kmalloc(sizeof(isdn_v110_stream), GFP_ATOMIC)) == NULL)
- return NULL;
- memset(v, 0, sizeof(isdn_v110_stream));
- v->key = key;
- v->nbits = 0;
- for (i = 0; key & (1 << i); i++)
- v->nbits++;
- v->nbytes = 8 / v->nbits;
- v->decodelen = 0;
- switch (key) {
- case V110_38400:
- v->OnlineFrame = V110_OnMatrix_38400;
- v->OfflineFrame = V110_OffMatrix_38400;
- break;
- case V110_19200:
- v->OnlineFrame = V110_OnMatrix_19200;
- v->OfflineFrame = V110_OffMatrix_19200;
- break;
- default:
- v->OnlineFrame = V110_OnMatrix_9600;
- v->OfflineFrame = V110_OffMatrix_9600;
- break;
- }
- v->framelen = v->nbytes * 10;
- v->SyncInit = 5;
- v->introducer = 0;
- v->dbit = 1;
- v->b = 0;
- v->skbres = hdrlen;
- v->maxsize = maxsize - hdrlen;
- if ((v->encodebuf = kmalloc(maxsize, GFP_ATOMIC)) == NULL) {
- kfree(v);
- return NULL;
- }
- return v;
- }
- /* isdn_v110_close frees private V.110 data structures */
- void
- isdn_v110_close(isdn_v110_stream * v)
- {
- if (v == NULL)
- return;
- #ifdef ISDN_V110_DEBUG
- printk(KERN_DEBUG "v110 closen");
- #endif
- kfree(v->encodebuf);
- kfree(v);
- }
- /*
- * ValidHeaderBytes return the number of valid bytes in v->decodebuf
- */
- static int
- ValidHeaderBytes(isdn_v110_stream * v)
- {
- int i;
- for (i = 0; (i < v->decodelen) && (i < v->nbytes); i++)
- if ((v->decodebuf[i] & v->key) != 0)
- break;
- return i;
- }
- /*
- * SyncHeader moves the decodebuf ptr to the next valid header
- */
- static void
- SyncHeader(isdn_v110_stream * v)
- {
- unsigned char *rbuf = v->decodebuf;
- int len = v->decodelen;
- if (len == 0)
- return;
- for (rbuf++, len--; len > 0; len--, rbuf++) /* such den SyncHeader in buf ! */
- if ((*rbuf & v->key) == 0) /* erstes byte gefunden ? */
- break; /* jupp! */
- if (len)
- memcpy(v->decodebuf, rbuf, len);
- v->decodelen = len;
- #ifdef ISDN_V110_DEBUG
- printk(KERN_DEBUG "isdn_v110: Header resyncn");
- #endif
- }
- /* DecodeMatrix takes n (n>=1) matrices (v110 frames, 10 bytes) where
- len is the number of matrix-lines. len must be a multiple of 10, i.e.
- only complete matices must be given.
- From these, netto data is extracted and returned in buf. The return-value
- is the bytecount of the decoded data.
- */
- static int
- DecodeMatrix(isdn_v110_stream * v, unsigned char *m, int len, unsigned char *buf)
- {
- int line = 0;
- int buflen = 0;
- int mbit = 64;
- int introducer = v->introducer;
- int dbit = v->dbit;
- unsigned char b = v->b;
- while (line < len) { /* Are we done with all lines of the matrix? */
- if ((line % 10) == 0) { /* the 0. line of the matrix is always 0 ! */
- if (m[line] != 0x00) { /* not 0 ? -> error! */
- #ifdef ISDN_V110_DEBUG
- printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad Headern");
- /* returning now is not the right thing, though :-( */
- #endif
- }
- line++; /* next line of matrix */
- continue;
- } else if ((line % 10) == 5) { /* in line 5 there's only e-bits ! */
- if ((m[line] & 0x70) != 0x30) { /* 011 has to be at the beginning! */
- #ifdef ISDN_V110_DEBUG
- printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad 5th linen");
- /* returning now is not the right thing, though :-( */
- #endif
- }
- line++; /* next line */
- continue;
- } else if (!introducer) { /* every byte starts with 10 (stopbit, startbit) */
- introducer = (m[line] & mbit) ? 0 : 1; /* current bit of the matrix */
- next_byte:
- if (mbit > 2) { /* was it the last bit in this line ? */
- mbit >>= 1; /* no -> take next */
- continue;
- } /* otherwise start with leftmost bit in the next line */
- mbit = 64;
- line++;
- continue;
- } else { /* otherwise we need to set a data bit */
- if (m[line] & mbit) /* was that bit set in the matrix ? */
- b |= dbit; /* yes -> set it in the data byte */
- else
- b &= dbit - 1; /* no -> clear it in the data byte */
- if (dbit < 128) /* is that data byte done ? */
- dbit <<= 1; /* no, got the next bit */
- else { /* data byte is done */
- buf[buflen++] = b; /* copy byte into the output buffer */
- introducer = b = 0; /* init of the intro sequence and of the data byte */
- dbit = 1; /* next we look for the 0th bit */
- }
- goto next_byte; /* look for next bit in the matrix */
- }
- }
- v->introducer = introducer;
- v->dbit = dbit;
- v->b = b;
- return buflen; /* return number of bytes in the output buffer */
- }
- /*
- * DecodeStream receives V.110 coded data from the input stream. It recovers the
- * original frames.
- * The input stream doesn't need to be framed
- */
- struct sk_buff *
- isdn_v110_decode(isdn_v110_stream * v, struct sk_buff *skb)
- {
- int i;
- int j;
- int len;
- unsigned char *v110_buf;
- unsigned char *rbuf;
- if (!skb) {
- printk(KERN_WARNING "isdn_v110_decode called with NULL skb!n");
- return NULL;
- }
- rbuf = skb->data;
- len = skb->len;
- if (v == NULL) {
- /* invalid handle, no chance to proceed */
- printk(KERN_WARNING "isdn_v110_decode called with NULL stream!n");
- dev_kfree_skb(skb);
- return NULL;
- }
- if (v->decodelen == 0) /* cache empty? */
- for (; len > 0; len--, rbuf++) /* scan for SyncHeader in buf */
- if ((*rbuf & v->key) == 0)
- break; /* found first byte */
- if (len == 0) {
- dev_kfree_skb(skb);
- return NULL;
- }
- /* copy new data to decode-buffer */
- memcpy(&(v->decodebuf[v->decodelen]), rbuf, len);
- v->decodelen += len;
- ReSync:
- if (v->decodelen < v->nbytes) { /* got a new header ? */
- dev_kfree_skb(skb);
- return NULL; /* no, try later */
- }
- if (ValidHeaderBytes(v) != v->nbytes) { /* is that a valid header? */
- SyncHeader(v); /* no -> look for header */
- goto ReSync;
- }
- len = (v->decodelen - (v->decodelen % (10 * v->nbytes))) / v->nbytes;
- if ((v110_buf = kmalloc(len, GFP_ATOMIC)) == NULL) {
- printk(KERN_WARNING "isdn_v110_decode: Couldn't allocate v110_bufn");
- dev_kfree_skb(skb);
- return NULL;
- }
- for (i = 0; i < len; i++) {
- v110_buf[i] = 0;
- for (j = 0; j < v->nbytes; j++)
- v110_buf[i] |= (v->decodebuf[(i * v->nbytes) + j] & v->key) << (8 - ((j + 1) * v->nbits));
- v110_buf[i] = FlipBits(v110_buf[i], v->nbits);
- }
- v->decodelen = (v->decodelen % (10 * v->nbytes));
- memcpy(v->decodebuf, &(v->decodebuf[len * v->nbytes]), v->decodelen);
- skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
- kfree(v110_buf);
- if (skb->len)
- return skb;
- else {
- kfree_skb(skb);
- return NULL;
- }
- }
- /* EncodeMatrix takes input data in buf, len is the bytecount.
- Data is encoded into v110 frames in m. Return value is the number of
- matrix-lines generated.
- */
- static int
- EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
- {
- int line = 0;
- int i = 0;
- int mbit = 128;
- int dbit = 1;
- int introducer = 3;
- int ibit[] = {0, 1, 1};
- while ((i < len) && (line < mlen)) { /* while we still have input data */
- switch (line % 10) { /* in which line of the matrix are we? */
- case 0:
- m[line++] = 0x00; /* line 0 is always 0 */
- mbit = 128; /* go on with the 7th bit */
- break;
- case 5:
- m[line++] = 0xbf; /* line 5 is always 10111111 */
- mbit = 128; /* go on with the 7th bit */
- break;
- }
- if (line >= mlen) {
- printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!n");
- return line;
- }
- next_bit:
- switch (mbit) { /* leftmost or rightmost bit ? */
- case 1:
- line++; /* rightmost -> go to next line */
- if (line >= mlen) {
- printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!n");
- return line;
- }
- case 128:
- m[line] = 128; /* leftmost -> set byte to 1000000 */
- mbit = 64; /* current bit in the matrix line */
- continue;
- }
- if (introducer) { /* set 110 sequence ? */
- introducer--; /* set on digit less */
- m[line] |= ibit[introducer] ? mbit : 0; /* set corresponding bit */
- mbit >>= 1; /* bit of matrix line >> 1 */
- goto next_bit; /* and go on there */
- } /* else push data bits into the matrix! */
- m[line] |= (buf[i] & dbit) ? mbit : 0; /* set data bit in matrix */
- if (dbit == 128) { /* was it the last one? */
- dbit = 1; /* then go on with first bit of */
- i++; /* next byte in input buffer */
- if (i < len) /* input buffer done ? */
- introducer = 3; /* no, write introducer 110 */
- else { /* input buffer done ! */
- m[line] |= (mbit - 1) & 0xfe; /* set remaining bits in line to 1 */
- break;
- }
- } else /* not the last data bit */
- dbit <<= 1; /* then go to next data bit */
- mbit >>= 1; /* go to next bit of matrix */
- goto next_bit;
- }
- /* if necessary, generate remaining lines of the matrix... */
- if ((line) && ((line + 10) < mlen))
- switch (++line % 10) {
- case 1:
- m[line++] = 0xfe;
- case 2:
- m[line++] = 0xfe;
- case 3:
- m[line++] = 0xfe;
- case 4:
- m[line++] = 0xfe;
- case 5:
- m[line++] = 0xbf;
- case 6:
- m[line++] = 0xfe;
- case 7:
- m[line++] = 0xfe;
- case 8:
- m[line++] = 0xfe;
- case 9:
- m[line++] = 0xfe;
- }
- return line; /* that's how many lines we have */
- }
- /*
- * Build a sync frame.
- */
- static struct sk_buff *
- isdn_v110_sync(isdn_v110_stream *v)
- {
- struct sk_buff *skb;
- if (v == NULL) {
- /* invalid handle, no chance to proceed */
- printk(KERN_WARNING "isdn_v110_sync called with NULL stream!n");
- return NULL;
- }
- if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
- skb_reserve(skb, v->skbres);
- memcpy(skb_put(skb, v->framelen), v->OfflineFrame, v->framelen);
- }
- return skb;
- }
- /*
- * Build an idle frame.
- */
- static struct sk_buff *
- isdn_v110_idle(isdn_v110_stream *v)
- {
- struct sk_buff *skb;
- if (v == NULL) {
- /* invalid handle, no chance to proceed */
- printk(KERN_WARNING "isdn_v110_sync called with NULL stream!n");
- return NULL;
- }
- if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
- skb_reserve(skb, v->skbres);
- memcpy(skb_put(skb, v->framelen), v->OnlineFrame, v->framelen);
- }
- return skb;
- }
- struct sk_buff *
- isdn_v110_encode(isdn_v110_stream * v, struct sk_buff *skb)
- {
- int i;
- int j;
- int rlen;
- int mlen;
- int olen;
- int size;
- int sval1;
- int sval2;
- int nframes;
- unsigned char *v110buf;
- unsigned char *rbuf;
- struct sk_buff *nskb;
- if (v == NULL) {
- /* invalid handle, no chance to proceed */
- printk(KERN_WARNING "isdn_v110_encode called with NULL stream!n");
- return NULL;
- }
- if (!skb) {
- /* invalid skb, no chance to proceed */
- printk(KERN_WARNING "isdn_v110_encode called with NULL skb!n");
- return NULL;
- }
- rlen = skb->len;
- nframes = (rlen + 3) / 4;
- v110buf = v->encodebuf;
- if ((nframes * 40) > v->maxsize) {
- size = v->maxsize;
- rlen = v->maxsize / 40;
- } else
- size = nframes * 40;
- if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
- printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skbn");
- return NULL;
- }
- skb_reserve(nskb, v->skbres + sizeof(int));
- if (skb->len == 0) {
- memcpy(skb_put(nskb, v->framelen), v->OnlineFrame, v->framelen);
- *((int *)skb_push(nskb, sizeof(int))) = 0;
- return nskb;
- }
- mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
- /* now distribute 2 or 4 bits each to the output stream! */
- rbuf = skb_put(nskb, size);
- olen = 0;
- sval1 = 8 - v->nbits;
- sval2 = v->key << sval1;
- for (i = 0; i < mlen; i++) {
- v110buf[i] = FlipBits(v110buf[i], v->nbits);
- for (j = 0; j < v->nbytes; j++) {
- if (size--)
- *rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
- else {
- printk(KERN_WARNING "isdn_v110_encode: buffers full!n");
- goto buffer_full;
- }
- olen++;
- }
- }
- buffer_full:
- skb_trim(nskb, olen);
- *((int *)skb_push(nskb, sizeof(int))) = rlen;
- return nskb;
- }
- int
- isdn_v110_stat_callback(int idx, isdn_ctrl * c)
- {
- isdn_v110_stream *v = NULL;
- int i;
- int ret;
- if (idx < 0)
- return 0;
- switch (c->command) {
- case ISDN_STAT_BSENT:
- /* Keep the send-queue of the driver filled
- * with frames:
- * If number of outstanding frames < 3,
- * send down an Idle-Frame (or an Sync-Frame, if
- * v->SyncInit != 0).
- */
- if (!(v = dev->v110[idx]))
- return 0;
- atomic_inc(&dev->v110use[idx]);
- if (v->skbidle > 0) {
- v->skbidle--;
- ret = 1;
- } else {
- if (v->skbuser > 0)
- v->skbuser--;
- ret = 0;
- }
- for (i = v->skbuser + v->skbidle; i < 2; i++) {
- struct sk_buff *skb;
- if (v->SyncInit > 0)
- skb = isdn_v110_sync(v);
- else
- skb = isdn_v110_idle(v);
- if (skb) {
- if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
- dev_kfree_skb(skb);
- break;
- } else {
- if (v->SyncInit)
- v->SyncInit--;
- v->skbidle++;
- }
- } else
- break;
- }
- atomic_dec(&dev->v110use[idx]);
- return ret;
- case ISDN_STAT_DHUP:
- case ISDN_STAT_BHUP:
- while (1) {
- atomic_inc(&dev->v110use[idx]);
- if (atomic_dec_and_test(&dev->v110use[idx])) {
- isdn_v110_close(dev->v110[idx]);
- dev->v110[idx] = NULL;
- break;
- }
- sti();
- }
- break;
- case ISDN_STAT_BCONN:
- if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
- int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
- int maxsize = dev->drv[c->driver]->interface->maxbufsize;
- atomic_inc(&dev->v110use[idx]);
- switch (dev->v110emu[idx]) {
- case ISDN_PROTO_L2_V11096:
- dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
- break;
- case ISDN_PROTO_L2_V11019:
- dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
- break;
- case ISDN_PROTO_L2_V11038:
- dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
- break;
- default:;
- }
- if ((v = dev->v110[idx])) {
- while (v->SyncInit) {
- struct sk_buff *skb = isdn_v110_sync(v);
- if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
- dev_kfree_skb(skb);
- /* Unable to send, try later */
- break;
- }
- v->SyncInit--;
- v->skbidle++;
- }
- } else
- printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %dn", idx);
- atomic_dec(&dev->v110use[idx]);
- }
- break;
- default:
- return 0;
- }
- return 0;
- }