1 /* 2 * This program is free software; you can distribute it and/or modify it 3 * under the terms of the GNU General Public License (Version 2) as 4 * published by the Free Software Foundation. 5 * 6 * This program is distributed in the hope it will be useful, but WITHOUT 7 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 8 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 9 * for more details. 10 * 11 * You should have received a copy of the GNU General Public License along 12 * with this program; if not, write to the Free Software Foundation, Inc., 13 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. 14 * 15 * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl> 16 * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org> 17 * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de> 18 */ 19 #include <linux/module.h> 20 #include <asm/system.h> 21 #include <linux/bitops.h> 22 #include <asm/uaccess.h> 23 #include <linux/crc16.h> 24 #include <linux/string.h> 25 #include <linux/mm.h> 26 #include <linux/interrupt.h> 27 #include <linux/in.h> 28 #include <linux/inet.h> 29 #include <linux/tty.h> 30 #include <linux/errno.h> 31 #include <linux/netdevice.h> 32 #include <linux/major.h> 33 #include <linux/init.h> 34 #include <linux/rtnetlink.h> 35 #include <linux/etherdevice.h> 36 #include <linux/skbuff.h> 37 #include <linux/if_arp.h> 38 #include <linux/jiffies.h> 39 40 #include <net/ax25.h> 41 42 #define AX_MTU 236 43 44 /* SLIP/KISS protocol characters. */ 45 #define END 0300 /* indicates end of frame */ 46 #define ESC 0333 /* indicates byte stuffing */ 47 #define ESC_END 0334 /* ESC ESC_END means END 'data' */ 48 #define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */ 49 50 struct mkiss { 51 struct tty_struct *tty; /* ptr to TTY structure */ 52 struct net_device *dev; /* easy for intr handling */ 53 54 /* These are pointers to the malloc()ed frame buffers. */ 55 spinlock_t buflock;/* lock for rbuf and xbuf */ 56 unsigned char *rbuff; /* receiver buffer */ 57 int rcount; /* received chars counter */ 58 unsigned char *xbuff; /* transmitter buffer */ 59 unsigned char *xhead; /* pointer to next byte to XMIT */ 60 int xleft; /* bytes left in XMIT queue */ 61 62 struct net_device_stats stats; 63 64 /* Detailed SLIP statistics. */ 65 int mtu; /* Our mtu (to spot changes!) */ 66 int buffsize; /* Max buffers sizes */ 67 68 unsigned long flags; /* Flag values/ mode etc */ 69 /* long req'd: used by set_bit --RR */ 70 #define AXF_INUSE 0 /* Channel in use */ 71 #define AXF_ESCAPE 1 /* ESC received */ 72 #define AXF_ERROR 2 /* Parity, etc. error */ 73 #define AXF_KEEPTEST 3 /* Keepalive test flag */ 74 #define AXF_OUTWAIT 4 /* is outpacket was flag */ 75 76 int mode; 77 int crcmode; /* MW: for FlexNet, SMACK etc. */ 78 int crcauto; /* CRC auto mode */ 79 80 #define CRC_MODE_NONE 0 81 #define CRC_MODE_FLEX 1 82 #define CRC_MODE_SMACK 2 83 #define CRC_MODE_FLEX_TEST 3 84 #define CRC_MODE_SMACK_TEST 4 85 86 atomic_t refcnt; 87 struct semaphore dead_sem; 88 }; 89 90 /*---------------------------------------------------------------------------*/ 91 92 static const unsigned short crc_flex_table[] = { 93 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38, 94 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770, 95 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9, 96 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1, 97 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a, 98 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672, 99 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb, 100 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3, 101 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c, 102 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574, 103 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd, 104 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5, 105 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e, 106 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476, 107 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf, 108 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7, 109 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30, 110 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378, 111 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1, 112 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9, 113 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32, 114 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a, 115 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3, 116 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb, 117 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34, 118 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c, 119 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5, 120 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd, 121 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36, 122 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e, 123 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7, 124 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff 125 }; 126 127 static unsigned short calc_crc_flex(unsigned char *cp, int size) 128 { 129 unsigned short crc = 0xffff; 130 131 while (size--) 132 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; 133 134 return crc; 135 } 136 137 static int check_crc_flex(unsigned char *cp, int size) 138 { 139 unsigned short crc = 0xffff; 140 141 if (size < 3) 142 return -1; 143 144 while (size--) 145 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; 146 147 if ((crc & 0xffff) != 0x7070) 148 return -1; 149 150 return 0; 151 } 152 153 static int check_crc_16(unsigned char *cp, int size) 154 { 155 unsigned short crc = 0x0000; 156 157 if (size < 3) 158 return -1; 159 160 crc = crc16(0, cp, size); 161 162 if (crc != 0x0000) 163 return -1; 164 165 return 0; 166 } 167 168 /* 169 * Standard encapsulation 170 */ 171 172 static int kiss_esc(unsigned char *s, unsigned char *d, int len) 173 { 174 unsigned char *ptr = d; 175 unsigned char c; 176 177 /* 178 * Send an initial END character to flush out any data that may have 179 * accumulated in the receiver due to line noise. 180 */ 181 182 *ptr++ = END; 183 184 while (len-- > 0) { 185 switch (c = *s++) { 186 case END: 187 *ptr++ = ESC; 188 *ptr++ = ESC_END; 189 break; 190 case ESC: 191 *ptr++ = ESC; 192 *ptr++ = ESC_ESC; 193 break; 194 default: 195 *ptr++ = c; 196 break; 197 } 198 } 199 200 *ptr++ = END; 201 202 return ptr - d; 203 } 204 205 /* 206 * MW: 207 * OK its ugly, but tell me a better solution without copying the 208 * packet to a temporary buffer :-) 209 */ 210 static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc, 211 int len) 212 { 213 unsigned char *ptr = d; 214 unsigned char c=0; 215 216 *ptr++ = END; 217 while (len > 0) { 218 if (len > 2) 219 c = *s++; 220 else if (len > 1) 221 c = crc >> 8; 222 else if (len > 0) 223 c = crc & 0xff; 224 225 len--; 226 227 switch (c) { 228 case END: 229 *ptr++ = ESC; 230 *ptr++ = ESC_END; 231 break; 232 case ESC: 233 *ptr++ = ESC; 234 *ptr++ = ESC_ESC; 235 break; 236 default: 237 *ptr++ = c; 238 break; 239 } 240 } 241 *ptr++ = END; 242 243 return ptr - d; 244 } 245 246 /* Send one completely decapsulated AX.25 packet to the AX.25 layer. */ 247 static void ax_bump(struct mkiss *ax) 248 { 249 struct sk_buff *skb; 250 int count; 251 252 spin_lock_bh(&ax->buflock); 253 if (ax->rbuff[0] > 0x0f) { 254 if (ax->rbuff[0] & 0x80) { 255 if (check_crc_16(ax->rbuff, ax->rcount) < 0) { 256 ax->stats.rx_errors++; 257 spin_unlock_bh(&ax->buflock); 258 259 return; 260 } 261 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) { 262 printk(KERN_INFO 263 "mkiss: %s: Switchting to crc-smack\n", 264 ax->dev->name); 265 ax->crcmode = CRC_MODE_SMACK; 266 } 267 ax->rcount -= 2; 268 *ax->rbuff &= ~0x80; 269 } else if (ax->rbuff[0] & 0x20) { 270 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) { 271 ax->stats.rx_errors++; 272 spin_unlock_bh(&ax->buflock); 273 return; 274 } 275 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) { 276 printk(KERN_INFO 277 "mkiss: %s: Switchting to crc-flexnet\n", 278 ax->dev->name); 279 ax->crcmode = CRC_MODE_FLEX; 280 } 281 ax->rcount -= 2; 282 283 /* 284 * dl9sau bugfix: the trailling two bytes flexnet crc 285 * will not be passed to the kernel. thus we have to 286 * correct the kissparm signature, because it indicates 287 * a crc but there's none 288 */ 289 *ax->rbuff &= ~0x20; 290 } 291 } 292 spin_unlock_bh(&ax->buflock); 293 294 count = ax->rcount; 295 296 if ((skb = dev_alloc_skb(count)) == NULL) { 297 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n", 298 ax->dev->name); 299 ax->stats.rx_dropped++; 300 return; 301 } 302 303 spin_lock_bh(&ax->buflock); 304 memcpy(skb_put(skb,count), ax->rbuff, count); 305 spin_unlock_bh(&ax->buflock); 306 skb->protocol = ax25_type_trans(skb, ax->dev); 307 netif_rx(skb); 308 ax->dev->last_rx = jiffies; 309 ax->stats.rx_packets++; 310 ax->stats.rx_bytes += count; 311 } 312 313 static void kiss_unesc(struct mkiss *ax, unsigned char s) 314 { 315 switch (s) { 316 case END: 317 /* drop keeptest bit = VSV */ 318 if (test_bit(AXF_KEEPTEST, &ax->flags)) 319 clear_bit(AXF_KEEPTEST, &ax->flags); 320 321 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2)) 322 ax_bump(ax); 323 324 clear_bit(AXF_ESCAPE, &ax->flags); 325 ax->rcount = 0; 326 return; 327 328 case ESC: 329 set_bit(AXF_ESCAPE, &ax->flags); 330 return; 331 case ESC_ESC: 332 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) 333 s = ESC; 334 break; 335 case ESC_END: 336 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) 337 s = END; 338 break; 339 } 340 341 spin_lock_bh(&ax->buflock); 342 if (!test_bit(AXF_ERROR, &ax->flags)) { 343 if (ax->rcount < ax->buffsize) { 344 ax->rbuff[ax->rcount++] = s; 345 spin_unlock_bh(&ax->buflock); 346 return; 347 } 348 349 ax->stats.rx_over_errors++; 350 set_bit(AXF_ERROR, &ax->flags); 351 } 352 spin_unlock_bh(&ax->buflock); 353 } 354 355 static int ax_set_mac_address(struct net_device *dev, void *addr) 356 { 357 struct sockaddr_ax25 *sa = addr; 358 359 netif_tx_lock_bh(dev); 360 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); 361 netif_tx_unlock_bh(dev); 362 363 return 0; 364 } 365 366 /*---------------------------------------------------------------------------*/ 367 368 static void ax_changedmtu(struct mkiss *ax) 369 { 370 struct net_device *dev = ax->dev; 371 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff; 372 int len; 373 374 len = dev->mtu * 2; 375 376 /* 377 * allow for arrival of larger UDP packets, even if we say not to 378 * also fixes a bug in which SunOS sends 512-byte packets even with 379 * an MSS of 128 380 */ 381 if (len < 576 * 2) 382 len = 576 * 2; 383 384 xbuff = kmalloc(len + 4, GFP_ATOMIC); 385 rbuff = kmalloc(len + 4, GFP_ATOMIC); 386 387 if (xbuff == NULL || rbuff == NULL) { 388 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, " 389 "MTU change cancelled.\n", 390 ax->dev->name); 391 dev->mtu = ax->mtu; 392 kfree(xbuff); 393 kfree(rbuff); 394 return; 395 } 396 397 spin_lock_bh(&ax->buflock); 398 399 oxbuff = ax->xbuff; 400 ax->xbuff = xbuff; 401 orbuff = ax->rbuff; 402 ax->rbuff = rbuff; 403 404 if (ax->xleft) { 405 if (ax->xleft <= len) { 406 memcpy(ax->xbuff, ax->xhead, ax->xleft); 407 } else { 408 ax->xleft = 0; 409 ax->stats.tx_dropped++; 410 } 411 } 412 413 ax->xhead = ax->xbuff; 414 415 if (ax->rcount) { 416 if (ax->rcount <= len) { 417 memcpy(ax->rbuff, orbuff, ax->rcount); 418 } else { 419 ax->rcount = 0; 420 ax->stats.rx_over_errors++; 421 set_bit(AXF_ERROR, &ax->flags); 422 } 423 } 424 425 ax->mtu = dev->mtu + 73; 426 ax->buffsize = len; 427 428 spin_unlock_bh(&ax->buflock); 429 430 kfree(oxbuff); 431 kfree(orbuff); 432 } 433 434 /* Encapsulate one AX.25 packet and stuff into a TTY queue. */ 435 static void ax_encaps(struct net_device *dev, unsigned char *icp, int len) 436 { 437 struct mkiss *ax = netdev_priv(dev); 438 unsigned char *p; 439 int actual, count; 440 441 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */ 442 ax_changedmtu(ax); 443 444 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */ 445 len = ax->mtu; 446 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name); 447 ax->stats.tx_dropped++; 448 netif_start_queue(dev); 449 return; 450 } 451 452 p = icp; 453 454 spin_lock_bh(&ax->buflock); 455 if ((*p & 0x0f) != 0) { 456 /* Configuration Command (kissparms(1). 457 * Protocol spec says: never append CRC. 458 * This fixes a very old bug in the linux 459 * kiss driver. -- dl9sau */ 460 switch (*p & 0xff) { 461 case 0x85: 462 /* command from userspace especially for us, 463 * not for delivery to the tnc */ 464 if (len > 1) { 465 int cmd = (p[1] & 0xff); 466 switch(cmd) { 467 case 3: 468 ax->crcmode = CRC_MODE_SMACK; 469 break; 470 case 2: 471 ax->crcmode = CRC_MODE_FLEX; 472 break; 473 case 1: 474 ax->crcmode = CRC_MODE_NONE; 475 break; 476 case 0: 477 default: 478 ax->crcmode = CRC_MODE_SMACK_TEST; 479 cmd = 0; 480 } 481 ax->crcauto = (cmd ? 0 : 1); 482 printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd); 483 } 484 spin_unlock_bh(&ax->buflock); 485 netif_start_queue(dev); 486 487 return; 488 default: 489 count = kiss_esc(p, (unsigned char *)ax->xbuff, len); 490 } 491 } else { 492 unsigned short crc; 493 switch (ax->crcmode) { 494 case CRC_MODE_SMACK_TEST: 495 ax->crcmode = CRC_MODE_FLEX_TEST; 496 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name); 497 // fall through 498 case CRC_MODE_SMACK: 499 *p |= 0x80; 500 crc = swab16(crc16(0, p, len)); 501 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2); 502 break; 503 case CRC_MODE_FLEX_TEST: 504 ax->crcmode = CRC_MODE_NONE; 505 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name); 506 // fall through 507 case CRC_MODE_FLEX: 508 *p |= 0x20; 509 crc = calc_crc_flex(p, len); 510 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2); 511 break; 512 513 default: 514 count = kiss_esc(p, (unsigned char *)ax->xbuff, len); 515 } 516 } 517 spin_unlock_bh(&ax->buflock); 518 519 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); 520 actual = ax->tty->driver->write(ax->tty, ax->xbuff, count); 521 ax->stats.tx_packets++; 522 ax->stats.tx_bytes += actual; 523 524 ax->dev->trans_start = jiffies; 525 ax->xleft = count - actual; 526 ax->xhead = ax->xbuff + actual; 527 } 528 529 /* Encapsulate an AX.25 packet and kick it into a TTY queue. */ 530 static int ax_xmit(struct sk_buff *skb, struct net_device *dev) 531 { 532 struct mkiss *ax = netdev_priv(dev); 533 534 if (!netif_running(dev)) { 535 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name); 536 return 1; 537 } 538 539 if (netif_queue_stopped(dev)) { 540 /* 541 * May be we must check transmitter timeout here ? 542 * 14 Oct 1994 Dmitry Gorodchanin. 543 */ 544 if (time_before(jiffies, dev->trans_start + 20 * HZ)) { 545 /* 20 sec timeout not reached */ 546 return 1; 547 } 548 549 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name, 550 (ax->tty->driver->chars_in_buffer(ax->tty) || ax->xleft) ? 551 "bad line quality" : "driver error"); 552 553 ax->xleft = 0; 554 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); 555 netif_start_queue(dev); 556 } 557 558 /* We were not busy, so we are now... :-) */ 559 if (skb != NULL) { 560 netif_stop_queue(dev); 561 ax_encaps(dev, skb->data, skb->len); 562 kfree_skb(skb); 563 } 564 565 return 0; 566 } 567 568 static int ax_open_dev(struct net_device *dev) 569 { 570 struct mkiss *ax = netdev_priv(dev); 571 572 if (ax->tty == NULL) 573 return -ENODEV; 574 575 return 0; 576 } 577 578 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 579 580 /* Return the frame type ID */ 581 static int ax_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, 582 void *daddr, void *saddr, unsigned len) 583 { 584 #ifdef CONFIG_INET 585 if (type != htons(ETH_P_AX25)) 586 return ax25_hard_header(skb, dev, type, daddr, saddr, len); 587 #endif 588 return 0; 589 } 590 591 592 static int ax_rebuild_header(struct sk_buff *skb) 593 { 594 #ifdef CONFIG_INET 595 return ax25_rebuild_header(skb); 596 #else 597 return 0; 598 #endif 599 } 600 601 #endif /* CONFIG_{AX25,AX25_MODULE} */ 602 603 /* Open the low-level part of the AX25 channel. Easy! */ 604 static int ax_open(struct net_device *dev) 605 { 606 struct mkiss *ax = netdev_priv(dev); 607 unsigned long len; 608 609 if (ax->tty == NULL) 610 return -ENODEV; 611 612 /* 613 * Allocate the frame buffers: 614 * 615 * rbuff Receive buffer. 616 * xbuff Transmit buffer. 617 */ 618 len = dev->mtu * 2; 619 620 /* 621 * allow for arrival of larger UDP packets, even if we say not to 622 * also fixes a bug in which SunOS sends 512-byte packets even with 623 * an MSS of 128 624 */ 625 if (len < 576 * 2) 626 len = 576 * 2; 627 628 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) 629 goto norbuff; 630 631 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) 632 goto noxbuff; 633 634 ax->mtu = dev->mtu + 73; 635 ax->buffsize = len; 636 ax->rcount = 0; 637 ax->xleft = 0; 638 639 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */ 640 641 spin_lock_init(&ax->buflock); 642 643 return 0; 644 645 noxbuff: 646 kfree(ax->rbuff); 647 648 norbuff: 649 return -ENOMEM; 650 } 651 652 653 /* Close the low-level part of the AX25 channel. Easy! */ 654 static int ax_close(struct net_device *dev) 655 { 656 struct mkiss *ax = netdev_priv(dev); 657 658 if (ax->tty) 659 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); 660 661 netif_stop_queue(dev); 662 663 return 0; 664 } 665 666 static struct net_device_stats *ax_get_stats(struct net_device *dev) 667 { 668 struct mkiss *ax = netdev_priv(dev); 669 670 return &ax->stats; 671 } 672 673 static void ax_setup(struct net_device *dev) 674 { 675 static char ax25_bcast[AX25_ADDR_LEN] = 676 {'Q'<<1,'S'<<1,'T'<<1,' '<<1,' '<<1,' '<<1,'0'<<1}; 677 static char ax25_test[AX25_ADDR_LEN] = 678 {'L'<<1,'I'<<1,'N'<<1,'U'<<1,'X'<<1,' '<<1,'1'<<1}; 679 680 /* Finish setting up the DEVICE info. */ 681 dev->mtu = AX_MTU; 682 dev->hard_start_xmit = ax_xmit; 683 dev->open = ax_open_dev; 684 dev->stop = ax_close; 685 dev->get_stats = ax_get_stats; 686 dev->set_mac_address = ax_set_mac_address; 687 dev->hard_header_len = 0; 688 dev->addr_len = 0; 689 dev->type = ARPHRD_AX25; 690 dev->tx_queue_len = 10; 691 dev->hard_header = ax_header; 692 dev->rebuild_header = ax_rebuild_header; 693 694 memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN); 695 memcpy(dev->dev_addr, ax25_test, AX25_ADDR_LEN); 696 697 dev->flags = IFF_BROADCAST | IFF_MULTICAST; 698 } 699 700 /* 701 * We have a potential race on dereferencing tty->disc_data, because the tty 702 * layer provides no locking at all - thus one cpu could be running 703 * sixpack_receive_buf while another calls sixpack_close, which zeroes 704 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The 705 * best way to fix this is to use a rwlock in the tty struct, but for now we 706 * use a single global rwlock for all ttys in ppp line discipline. 707 */ 708 static DEFINE_RWLOCK(disc_data_lock); 709 710 static struct mkiss *mkiss_get(struct tty_struct *tty) 711 { 712 struct mkiss *ax; 713 714 read_lock(&disc_data_lock); 715 ax = tty->disc_data; 716 if (ax) 717 atomic_inc(&ax->refcnt); 718 read_unlock(&disc_data_lock); 719 720 return ax; 721 } 722 723 static void mkiss_put(struct mkiss *ax) 724 { 725 if (atomic_dec_and_test(&ax->refcnt)) 726 up(&ax->dead_sem); 727 } 728 729 static int crc_force = 0; /* Can be overridden with insmod */ 730 731 static int mkiss_open(struct tty_struct *tty) 732 { 733 struct net_device *dev; 734 struct mkiss *ax; 735 int err; 736 737 if (!capable(CAP_NET_ADMIN)) 738 return -EPERM; 739 740 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup); 741 if (!dev) { 742 err = -ENOMEM; 743 goto out; 744 } 745 746 ax = netdev_priv(dev); 747 ax->dev = dev; 748 749 spin_lock_init(&ax->buflock); 750 atomic_set(&ax->refcnt, 1); 751 init_MUTEX_LOCKED(&ax->dead_sem); 752 753 ax->tty = tty; 754 tty->disc_data = ax; 755 tty->receive_room = 65535; 756 757 if (tty->driver->flush_buffer) 758 tty->driver->flush_buffer(tty); 759 760 /* Restore default settings */ 761 dev->type = ARPHRD_AX25; 762 763 /* Perform the low-level AX25 initialization. */ 764 if ((err = ax_open(ax->dev))) { 765 goto out_free_netdev; 766 } 767 768 if (register_netdev(dev)) 769 goto out_free_buffers; 770 771 /* after register_netdev() - because else printk smashes the kernel */ 772 switch (crc_force) { 773 case 3: 774 ax->crcmode = CRC_MODE_SMACK; 775 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n", 776 ax->dev->name); 777 break; 778 case 2: 779 ax->crcmode = CRC_MODE_FLEX; 780 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n", 781 ax->dev->name); 782 break; 783 case 1: 784 ax->crcmode = CRC_MODE_NONE; 785 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n", 786 ax->dev->name); 787 break; 788 case 0: 789 /* fall through */ 790 default: 791 crc_force = 0; 792 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n", 793 ax->dev->name); 794 ax->crcmode = CRC_MODE_SMACK_TEST; 795 } 796 ax->crcauto = (crc_force ? 0 : 1); 797 798 netif_start_queue(dev); 799 800 /* Done. We have linked the TTY line to a channel. */ 801 return 0; 802 803 out_free_buffers: 804 kfree(ax->rbuff); 805 kfree(ax->xbuff); 806 807 out_free_netdev: 808 free_netdev(dev); 809 810 out: 811 return err; 812 } 813 814 static void mkiss_close(struct tty_struct *tty) 815 { 816 struct mkiss *ax; 817 818 write_lock(&disc_data_lock); 819 ax = tty->disc_data; 820 tty->disc_data = NULL; 821 write_unlock(&disc_data_lock); 822 823 if (ax == 0) 824 return; 825 826 /* 827 * We have now ensured that nobody can start using ap from now on, but 828 * we have to wait for all existing users to finish. 829 */ 830 if (!atomic_dec_and_test(&ax->refcnt)) 831 down(&ax->dead_sem); 832 833 unregister_netdev(ax->dev); 834 835 /* Free all AX25 frame buffers. */ 836 kfree(ax->rbuff); 837 kfree(ax->xbuff); 838 839 ax->tty = NULL; 840 } 841 842 /* Perform I/O control on an active ax25 channel. */ 843 static int mkiss_ioctl(struct tty_struct *tty, struct file *file, 844 unsigned int cmd, unsigned long arg) 845 { 846 struct mkiss *ax = mkiss_get(tty); 847 struct net_device *dev = ax->dev; 848 unsigned int tmp, err; 849 850 /* First make sure we're connected. */ 851 if (ax == NULL) 852 return -ENXIO; 853 854 switch (cmd) { 855 case SIOCGIFNAME: 856 err = copy_to_user((void __user *) arg, ax->dev->name, 857 strlen(ax->dev->name) + 1) ? -EFAULT : 0; 858 break; 859 860 case SIOCGIFENCAP: 861 err = put_user(4, (int __user *) arg); 862 break; 863 864 case SIOCSIFENCAP: 865 if (get_user(tmp, (int __user *) arg)) { 866 err = -EFAULT; 867 break; 868 } 869 870 ax->mode = tmp; 871 dev->addr_len = AX25_ADDR_LEN; 872 dev->hard_header_len = AX25_KISS_HEADER_LEN + 873 AX25_MAX_HEADER_LEN + 3; 874 dev->type = ARPHRD_AX25; 875 876 err = 0; 877 break; 878 879 case SIOCSIFHWADDR: { 880 char addr[AX25_ADDR_LEN]; 881 882 if (copy_from_user(&addr, 883 (void __user *) arg, AX25_ADDR_LEN)) { 884 err = -EFAULT; 885 break; 886 } 887 888 netif_tx_lock_bh(dev); 889 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN); 890 netif_tx_unlock_bh(dev); 891 892 err = 0; 893 break; 894 } 895 default: 896 err = -ENOIOCTLCMD; 897 } 898 899 mkiss_put(ax); 900 901 return err; 902 } 903 904 /* 905 * Handle the 'receiver data ready' interrupt. 906 * This function is called by the 'tty_io' module in the kernel when 907 * a block of data has been received, which can now be decapsulated 908 * and sent on to the AX.25 layer for further processing. 909 */ 910 static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp, 911 char *fp, int count) 912 { 913 struct mkiss *ax = mkiss_get(tty); 914 915 if (!ax) 916 return; 917 918 /* 919 * Argh! mtu change time! - costs us the packet part received 920 * at the change 921 */ 922 if (ax->mtu != ax->dev->mtu + 73) 923 ax_changedmtu(ax); 924 925 /* Read the characters out of the buffer */ 926 while (count--) { 927 if (fp != NULL && *fp++) { 928 if (!test_and_set_bit(AXF_ERROR, &ax->flags)) 929 ax->stats.rx_errors++; 930 cp++; 931 continue; 932 } 933 934 kiss_unesc(ax, *cp++); 935 } 936 937 mkiss_put(ax); 938 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) 939 && tty->driver->unthrottle) 940 tty->driver->unthrottle(tty); 941 } 942 943 /* 944 * Called by the driver when there's room for more data. If we have 945 * more packets to send, we send them here. 946 */ 947 static void mkiss_write_wakeup(struct tty_struct *tty) 948 { 949 struct mkiss *ax = mkiss_get(tty); 950 int actual; 951 952 if (!ax) 953 return; 954 955 if (ax->xleft <= 0) { 956 /* Now serial buffer is almost free & we can start 957 * transmission of another packet 958 */ 959 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 960 961 netif_wake_queue(ax->dev); 962 goto out; 963 } 964 965 actual = tty->driver->write(tty, ax->xhead, ax->xleft); 966 ax->xleft -= actual; 967 ax->xhead += actual; 968 969 out: 970 mkiss_put(ax); 971 } 972 973 static struct tty_ldisc ax_ldisc = { 974 .owner = THIS_MODULE, 975 .magic = TTY_LDISC_MAGIC, 976 .name = "mkiss", 977 .open = mkiss_open, 978 .close = mkiss_close, 979 .ioctl = mkiss_ioctl, 980 .receive_buf = mkiss_receive_buf, 981 .write_wakeup = mkiss_write_wakeup 982 }; 983 984 static char banner[] __initdata = KERN_INFO \ 985 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n"; 986 static char msg_regfail[] __initdata = KERN_ERR \ 987 "mkiss: can't register line discipline (err = %d)\n"; 988 989 static int __init mkiss_init_driver(void) 990 { 991 int status; 992 993 printk(banner); 994 995 if ((status = tty_register_ldisc(N_AX25, &ax_ldisc)) != 0) 996 printk(msg_regfail); 997 998 return status; 999 } 1000 1001 static const char msg_unregfail[] __exitdata = KERN_ERR \ 1002 "mkiss: can't unregister line discipline (err = %d)\n"; 1003 1004 static void __exit mkiss_exit_driver(void) 1005 { 1006 int ret; 1007 1008 if ((ret = tty_unregister_ldisc(N_AX25))) 1009 printk(msg_unregfail, ret); 1010 } 1011 1012 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>"); 1013 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs"); 1014 module_param(crc_force, int, 0); 1015 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]"); 1016 MODULE_LICENSE("GPL"); 1017 MODULE_ALIAS_LDISC(N_AX25); 1018 1019 module_init(mkiss_init_driver); 1020 module_exit(mkiss_exit_driver); 1021