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, see <http://www.gnu.org/licenses/>. 13 * 14 * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl> 15 * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org> 16 * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de> 17 */ 18 #include <linux/module.h> 19 #include <linux/bitops.h> 20 #include <asm/uaccess.h> 21 #include <linux/crc16.h> 22 #include <linux/string.h> 23 #include <linux/mm.h> 24 #include <linux/interrupt.h> 25 #include <linux/in.h> 26 #include <linux/inet.h> 27 #include <linux/slab.h> 28 #include <linux/tty.h> 29 #include <linux/errno.h> 30 #include <linux/netdevice.h> 31 #include <linux/major.h> 32 #include <linux/init.h> 33 #include <linux/rtnetlink.h> 34 #include <linux/etherdevice.h> 35 #include <linux/skbuff.h> 36 #include <linux/if_arp.h> 37 #include <linux/jiffies.h> 38 #include <linux/compat.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 /* Detailed SLIP statistics. */ 63 int mtu; /* Our mtu (to spot changes!) */ 64 int buffsize; /* Max buffers sizes */ 65 66 unsigned long flags; /* Flag values/ mode etc */ 67 /* long req'd: used by set_bit --RR */ 68 #define AXF_INUSE 0 /* Channel in use */ 69 #define AXF_ESCAPE 1 /* ESC received */ 70 #define AXF_ERROR 2 /* Parity, etc. error */ 71 #define AXF_KEEPTEST 3 /* Keepalive test flag */ 72 #define AXF_OUTWAIT 4 /* is outpacket was flag */ 73 74 int mode; 75 int crcmode; /* MW: for FlexNet, SMACK etc. */ 76 int crcauto; /* CRC auto mode */ 77 78 #define CRC_MODE_NONE 0 79 #define CRC_MODE_FLEX 1 80 #define CRC_MODE_SMACK 2 81 #define CRC_MODE_FLEX_TEST 3 82 #define CRC_MODE_SMACK_TEST 4 83 84 atomic_t refcnt; 85 struct semaphore dead_sem; 86 }; 87 88 /*---------------------------------------------------------------------------*/ 89 90 static const unsigned short crc_flex_table[] = { 91 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38, 92 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770, 93 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9, 94 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1, 95 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a, 96 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672, 97 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb, 98 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3, 99 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c, 100 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574, 101 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd, 102 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5, 103 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e, 104 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476, 105 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf, 106 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7, 107 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30, 108 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378, 109 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1, 110 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9, 111 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32, 112 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a, 113 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3, 114 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb, 115 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34, 116 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c, 117 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5, 118 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd, 119 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36, 120 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e, 121 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7, 122 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff 123 }; 124 125 static unsigned short calc_crc_flex(unsigned char *cp, int size) 126 { 127 unsigned short crc = 0xffff; 128 129 while (size--) 130 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; 131 132 return crc; 133 } 134 135 static int check_crc_flex(unsigned char *cp, int size) 136 { 137 unsigned short crc = 0xffff; 138 139 if (size < 3) 140 return -1; 141 142 while (size--) 143 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; 144 145 if ((crc & 0xffff) != 0x7070) 146 return -1; 147 148 return 0; 149 } 150 151 static int check_crc_16(unsigned char *cp, int size) 152 { 153 unsigned short crc = 0x0000; 154 155 if (size < 3) 156 return -1; 157 158 crc = crc16(0, cp, size); 159 160 if (crc != 0x0000) 161 return -1; 162 163 return 0; 164 } 165 166 /* 167 * Standard encapsulation 168 */ 169 170 static int kiss_esc(unsigned char *s, unsigned char *d, int len) 171 { 172 unsigned char *ptr = d; 173 unsigned char c; 174 175 /* 176 * Send an initial END character to flush out any data that may have 177 * accumulated in the receiver due to line noise. 178 */ 179 180 *ptr++ = END; 181 182 while (len-- > 0) { 183 switch (c = *s++) { 184 case END: 185 *ptr++ = ESC; 186 *ptr++ = ESC_END; 187 break; 188 case ESC: 189 *ptr++ = ESC; 190 *ptr++ = ESC_ESC; 191 break; 192 default: 193 *ptr++ = c; 194 break; 195 } 196 } 197 198 *ptr++ = END; 199 200 return ptr - d; 201 } 202 203 /* 204 * MW: 205 * OK its ugly, but tell me a better solution without copying the 206 * packet to a temporary buffer :-) 207 */ 208 static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc, 209 int len) 210 { 211 unsigned char *ptr = d; 212 unsigned char c=0; 213 214 *ptr++ = END; 215 while (len > 0) { 216 if (len > 2) 217 c = *s++; 218 else if (len > 1) 219 c = crc >> 8; 220 else if (len > 0) 221 c = crc & 0xff; 222 223 len--; 224 225 switch (c) { 226 case END: 227 *ptr++ = ESC; 228 *ptr++ = ESC_END; 229 break; 230 case ESC: 231 *ptr++ = ESC; 232 *ptr++ = ESC_ESC; 233 break; 234 default: 235 *ptr++ = c; 236 break; 237 } 238 } 239 *ptr++ = END; 240 241 return ptr - d; 242 } 243 244 /* Send one completely decapsulated AX.25 packet to the AX.25 layer. */ 245 static void ax_bump(struct mkiss *ax) 246 { 247 struct sk_buff *skb; 248 int count; 249 250 spin_lock_bh(&ax->buflock); 251 if (ax->rbuff[0] > 0x0f) { 252 if (ax->rbuff[0] & 0x80) { 253 if (check_crc_16(ax->rbuff, ax->rcount) < 0) { 254 ax->dev->stats.rx_errors++; 255 spin_unlock_bh(&ax->buflock); 256 257 return; 258 } 259 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) { 260 printk(KERN_INFO 261 "mkiss: %s: Switching to crc-smack\n", 262 ax->dev->name); 263 ax->crcmode = CRC_MODE_SMACK; 264 } 265 ax->rcount -= 2; 266 *ax->rbuff &= ~0x80; 267 } else if (ax->rbuff[0] & 0x20) { 268 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) { 269 ax->dev->stats.rx_errors++; 270 spin_unlock_bh(&ax->buflock); 271 return; 272 } 273 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) { 274 printk(KERN_INFO 275 "mkiss: %s: Switching to crc-flexnet\n", 276 ax->dev->name); 277 ax->crcmode = CRC_MODE_FLEX; 278 } 279 ax->rcount -= 2; 280 281 /* 282 * dl9sau bugfix: the trailling two bytes flexnet crc 283 * will not be passed to the kernel. thus we have to 284 * correct the kissparm signature, because it indicates 285 * a crc but there's none 286 */ 287 *ax->rbuff &= ~0x20; 288 } 289 } 290 291 count = ax->rcount; 292 293 if ((skb = dev_alloc_skb(count)) == NULL) { 294 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n", 295 ax->dev->name); 296 ax->dev->stats.rx_dropped++; 297 spin_unlock_bh(&ax->buflock); 298 return; 299 } 300 301 memcpy(skb_put(skb,count), ax->rbuff, count); 302 skb->protocol = ax25_type_trans(skb, ax->dev); 303 netif_rx(skb); 304 ax->dev->stats.rx_packets++; 305 ax->dev->stats.rx_bytes += count; 306 spin_unlock_bh(&ax->buflock); 307 } 308 309 static void kiss_unesc(struct mkiss *ax, unsigned char s) 310 { 311 switch (s) { 312 case END: 313 /* drop keeptest bit = VSV */ 314 if (test_bit(AXF_KEEPTEST, &ax->flags)) 315 clear_bit(AXF_KEEPTEST, &ax->flags); 316 317 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2)) 318 ax_bump(ax); 319 320 clear_bit(AXF_ESCAPE, &ax->flags); 321 ax->rcount = 0; 322 return; 323 324 case ESC: 325 set_bit(AXF_ESCAPE, &ax->flags); 326 return; 327 case ESC_ESC: 328 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) 329 s = ESC; 330 break; 331 case ESC_END: 332 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) 333 s = END; 334 break; 335 } 336 337 spin_lock_bh(&ax->buflock); 338 if (!test_bit(AXF_ERROR, &ax->flags)) { 339 if (ax->rcount < ax->buffsize) { 340 ax->rbuff[ax->rcount++] = s; 341 spin_unlock_bh(&ax->buflock); 342 return; 343 } 344 345 ax->dev->stats.rx_over_errors++; 346 set_bit(AXF_ERROR, &ax->flags); 347 } 348 spin_unlock_bh(&ax->buflock); 349 } 350 351 static int ax_set_mac_address(struct net_device *dev, void *addr) 352 { 353 struct sockaddr_ax25 *sa = addr; 354 355 netif_tx_lock_bh(dev); 356 netif_addr_lock(dev); 357 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); 358 netif_addr_unlock(dev); 359 netif_tx_unlock_bh(dev); 360 361 return 0; 362 } 363 364 /*---------------------------------------------------------------------------*/ 365 366 static void ax_changedmtu(struct mkiss *ax) 367 { 368 struct net_device *dev = ax->dev; 369 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff; 370 int len; 371 372 len = dev->mtu * 2; 373 374 /* 375 * allow for arrival of larger UDP packets, even if we say not to 376 * also fixes a bug in which SunOS sends 512-byte packets even with 377 * an MSS of 128 378 */ 379 if (len < 576 * 2) 380 len = 576 * 2; 381 382 xbuff = kmalloc(len + 4, GFP_ATOMIC); 383 rbuff = kmalloc(len + 4, GFP_ATOMIC); 384 385 if (xbuff == NULL || rbuff == NULL) { 386 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, " 387 "MTU change cancelled.\n", 388 ax->dev->name); 389 dev->mtu = ax->mtu; 390 kfree(xbuff); 391 kfree(rbuff); 392 return; 393 } 394 395 spin_lock_bh(&ax->buflock); 396 397 oxbuff = ax->xbuff; 398 ax->xbuff = xbuff; 399 orbuff = ax->rbuff; 400 ax->rbuff = rbuff; 401 402 if (ax->xleft) { 403 if (ax->xleft <= len) { 404 memcpy(ax->xbuff, ax->xhead, ax->xleft); 405 } else { 406 ax->xleft = 0; 407 dev->stats.tx_dropped++; 408 } 409 } 410 411 ax->xhead = ax->xbuff; 412 413 if (ax->rcount) { 414 if (ax->rcount <= len) { 415 memcpy(ax->rbuff, orbuff, ax->rcount); 416 } else { 417 ax->rcount = 0; 418 dev->stats.rx_over_errors++; 419 set_bit(AXF_ERROR, &ax->flags); 420 } 421 } 422 423 ax->mtu = dev->mtu + 73; 424 ax->buffsize = len; 425 426 spin_unlock_bh(&ax->buflock); 427 428 kfree(oxbuff); 429 kfree(orbuff); 430 } 431 432 /* Encapsulate one AX.25 packet and stuff into a TTY queue. */ 433 static void ax_encaps(struct net_device *dev, unsigned char *icp, int len) 434 { 435 struct mkiss *ax = netdev_priv(dev); 436 unsigned char *p; 437 int actual, count; 438 439 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */ 440 ax_changedmtu(ax); 441 442 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */ 443 len = ax->mtu; 444 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name); 445 dev->stats.tx_dropped++; 446 netif_start_queue(dev); 447 return; 448 } 449 450 p = icp; 451 452 spin_lock_bh(&ax->buflock); 453 if ((*p & 0x0f) != 0) { 454 /* Configuration Command (kissparms(1). 455 * Protocol spec says: never append CRC. 456 * This fixes a very old bug in the linux 457 * kiss driver. -- dl9sau */ 458 switch (*p & 0xff) { 459 case 0x85: 460 /* command from userspace especially for us, 461 * not for delivery to the tnc */ 462 if (len > 1) { 463 int cmd = (p[1] & 0xff); 464 switch(cmd) { 465 case 3: 466 ax->crcmode = CRC_MODE_SMACK; 467 break; 468 case 2: 469 ax->crcmode = CRC_MODE_FLEX; 470 break; 471 case 1: 472 ax->crcmode = CRC_MODE_NONE; 473 break; 474 case 0: 475 default: 476 ax->crcmode = CRC_MODE_SMACK_TEST; 477 cmd = 0; 478 } 479 ax->crcauto = (cmd ? 0 : 1); 480 printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd); 481 } 482 spin_unlock_bh(&ax->buflock); 483 netif_start_queue(dev); 484 485 return; 486 default: 487 count = kiss_esc(p, ax->xbuff, len); 488 } 489 } else { 490 unsigned short crc; 491 switch (ax->crcmode) { 492 case CRC_MODE_SMACK_TEST: 493 ax->crcmode = CRC_MODE_FLEX_TEST; 494 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name); 495 // fall through 496 case CRC_MODE_SMACK: 497 *p |= 0x80; 498 crc = swab16(crc16(0, p, len)); 499 count = kiss_esc_crc(p, ax->xbuff, crc, len+2); 500 break; 501 case CRC_MODE_FLEX_TEST: 502 ax->crcmode = CRC_MODE_NONE; 503 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name); 504 // fall through 505 case CRC_MODE_FLEX: 506 *p |= 0x20; 507 crc = calc_crc_flex(p, len); 508 count = kiss_esc_crc(p, ax->xbuff, crc, len+2); 509 break; 510 511 default: 512 count = kiss_esc(p, ax->xbuff, len); 513 } 514 } 515 spin_unlock_bh(&ax->buflock); 516 517 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); 518 actual = ax->tty->ops->write(ax->tty, ax->xbuff, count); 519 dev->stats.tx_packets++; 520 dev->stats.tx_bytes += actual; 521 522 ax->dev->trans_start = jiffies; 523 ax->xleft = count - actual; 524 ax->xhead = ax->xbuff + actual; 525 } 526 527 /* Encapsulate an AX.25 packet and kick it into a TTY queue. */ 528 static netdev_tx_t ax_xmit(struct sk_buff *skb, struct net_device *dev) 529 { 530 struct mkiss *ax = netdev_priv(dev); 531 532 if (!netif_running(dev)) { 533 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name); 534 return NETDEV_TX_BUSY; 535 } 536 537 if (netif_queue_stopped(dev)) { 538 /* 539 * May be we must check transmitter timeout here ? 540 * 14 Oct 1994 Dmitry Gorodchanin. 541 */ 542 if (time_before(jiffies, dev->trans_start + 20 * HZ)) { 543 /* 20 sec timeout not reached */ 544 return NETDEV_TX_BUSY; 545 } 546 547 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name, 548 (tty_chars_in_buffer(ax->tty) || ax->xleft) ? 549 "bad line quality" : "driver error"); 550 551 ax->xleft = 0; 552 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); 553 netif_start_queue(dev); 554 } 555 556 /* We were not busy, so we are now... :-) */ 557 if (skb != NULL) { 558 netif_stop_queue(dev); 559 ax_encaps(dev, skb->data, skb->len); 560 kfree_skb(skb); 561 } 562 563 return NETDEV_TX_OK; 564 } 565 566 static int ax_open_dev(struct net_device *dev) 567 { 568 struct mkiss *ax = netdev_priv(dev); 569 570 if (ax->tty == NULL) 571 return -ENODEV; 572 573 return 0; 574 } 575 576 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 577 578 /* Return the frame type ID */ 579 static int ax_header(struct sk_buff *skb, struct net_device *dev, 580 unsigned short type, const void *daddr, 581 const void *saddr, unsigned len) 582 { 583 #ifdef CONFIG_INET 584 if (type != ETH_P_AX25) 585 return ax25_hard_header(skb, dev, type, daddr, saddr, len); 586 #endif 587 return 0; 588 } 589 590 591 static int ax_rebuild_header(struct sk_buff *skb) 592 { 593 #ifdef CONFIG_INET 594 return ax25_rebuild_header(skb); 595 #else 596 return 0; 597 #endif 598 } 599 600 #endif /* CONFIG_{AX25,AX25_MODULE} */ 601 602 /* Open the low-level part of the AX25 channel. Easy! */ 603 static int ax_open(struct net_device *dev) 604 { 605 struct mkiss *ax = netdev_priv(dev); 606 unsigned long len; 607 608 if (ax->tty == NULL) 609 return -ENODEV; 610 611 /* 612 * Allocate the frame buffers: 613 * 614 * rbuff Receive buffer. 615 * xbuff Transmit buffer. 616 */ 617 len = dev->mtu * 2; 618 619 /* 620 * allow for arrival of larger UDP packets, even if we say not to 621 * also fixes a bug in which SunOS sends 512-byte packets even with 622 * an MSS of 128 623 */ 624 if (len < 576 * 2) 625 len = 576 * 2; 626 627 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) 628 goto norbuff; 629 630 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) 631 goto noxbuff; 632 633 ax->mtu = dev->mtu + 73; 634 ax->buffsize = len; 635 ax->rcount = 0; 636 ax->xleft = 0; 637 638 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */ 639 640 spin_lock_init(&ax->buflock); 641 642 return 0; 643 644 noxbuff: 645 kfree(ax->rbuff); 646 647 norbuff: 648 return -ENOMEM; 649 } 650 651 652 /* Close the low-level part of the AX25 channel. Easy! */ 653 static int ax_close(struct net_device *dev) 654 { 655 struct mkiss *ax = netdev_priv(dev); 656 657 if (ax->tty) 658 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); 659 660 netif_stop_queue(dev); 661 662 return 0; 663 } 664 665 static const struct header_ops ax_header_ops = { 666 .create = ax_header, 667 .rebuild = ax_rebuild_header, 668 }; 669 670 static const struct net_device_ops ax_netdev_ops = { 671 .ndo_open = ax_open_dev, 672 .ndo_stop = ax_close, 673 .ndo_start_xmit = ax_xmit, 674 .ndo_set_mac_address = ax_set_mac_address, 675 }; 676 677 static void ax_setup(struct net_device *dev) 678 { 679 /* Finish setting up the DEVICE info. */ 680 dev->mtu = AX_MTU; 681 dev->hard_header_len = 0; 682 dev->addr_len = 0; 683 dev->type = ARPHRD_AX25; 684 dev->tx_queue_len = 10; 685 dev->header_ops = &ax_header_ops; 686 dev->netdev_ops = &ax_netdev_ops; 687 688 689 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); 690 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); 691 692 dev->flags = IFF_BROADCAST | IFF_MULTICAST; 693 } 694 695 /* 696 * We have a potential race on dereferencing tty->disc_data, because the tty 697 * layer provides no locking at all - thus one cpu could be running 698 * sixpack_receive_buf while another calls sixpack_close, which zeroes 699 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The 700 * best way to fix this is to use a rwlock in the tty struct, but for now we 701 * use a single global rwlock for all ttys in ppp line discipline. 702 */ 703 static DEFINE_RWLOCK(disc_data_lock); 704 705 static struct mkiss *mkiss_get(struct tty_struct *tty) 706 { 707 struct mkiss *ax; 708 709 read_lock(&disc_data_lock); 710 ax = tty->disc_data; 711 if (ax) 712 atomic_inc(&ax->refcnt); 713 read_unlock(&disc_data_lock); 714 715 return ax; 716 } 717 718 static void mkiss_put(struct mkiss *ax) 719 { 720 if (atomic_dec_and_test(&ax->refcnt)) 721 up(&ax->dead_sem); 722 } 723 724 static int crc_force = 0; /* Can be overridden with insmod */ 725 726 static int mkiss_open(struct tty_struct *tty) 727 { 728 struct net_device *dev; 729 struct mkiss *ax; 730 int err; 731 732 if (!capable(CAP_NET_ADMIN)) 733 return -EPERM; 734 if (tty->ops->write == NULL) 735 return -EOPNOTSUPP; 736 737 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup); 738 if (!dev) { 739 err = -ENOMEM; 740 goto out; 741 } 742 743 ax = netdev_priv(dev); 744 ax->dev = dev; 745 746 spin_lock_init(&ax->buflock); 747 atomic_set(&ax->refcnt, 1); 748 sema_init(&ax->dead_sem, 0); 749 750 ax->tty = tty; 751 tty->disc_data = ax; 752 tty->receive_room = 65535; 753 754 tty_driver_flush_buffer(tty); 755 756 /* Restore default settings */ 757 dev->type = ARPHRD_AX25; 758 759 /* Perform the low-level AX25 initialization. */ 760 if ((err = ax_open(ax->dev))) { 761 goto out_free_netdev; 762 } 763 764 if (register_netdev(dev)) 765 goto out_free_buffers; 766 767 /* after register_netdev() - because else printk smashes the kernel */ 768 switch (crc_force) { 769 case 3: 770 ax->crcmode = CRC_MODE_SMACK; 771 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n", 772 ax->dev->name); 773 break; 774 case 2: 775 ax->crcmode = CRC_MODE_FLEX; 776 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n", 777 ax->dev->name); 778 break; 779 case 1: 780 ax->crcmode = CRC_MODE_NONE; 781 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n", 782 ax->dev->name); 783 break; 784 case 0: 785 /* fall through */ 786 default: 787 crc_force = 0; 788 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n", 789 ax->dev->name); 790 ax->crcmode = CRC_MODE_SMACK_TEST; 791 } 792 ax->crcauto = (crc_force ? 0 : 1); 793 794 netif_start_queue(dev); 795 796 /* Done. We have linked the TTY line to a channel. */ 797 return 0; 798 799 out_free_buffers: 800 kfree(ax->rbuff); 801 kfree(ax->xbuff); 802 803 out_free_netdev: 804 free_netdev(dev); 805 806 out: 807 return err; 808 } 809 810 static void mkiss_close(struct tty_struct *tty) 811 { 812 struct mkiss *ax; 813 814 write_lock_bh(&disc_data_lock); 815 ax = tty->disc_data; 816 tty->disc_data = NULL; 817 write_unlock_bh(&disc_data_lock); 818 819 if (!ax) 820 return; 821 822 /* 823 * We have now ensured that nobody can start using ap from now on, but 824 * we have to wait for all existing users to finish. 825 */ 826 if (!atomic_dec_and_test(&ax->refcnt)) 827 down(&ax->dead_sem); 828 829 unregister_netdev(ax->dev); 830 831 /* Free all AX25 frame buffers. */ 832 kfree(ax->rbuff); 833 kfree(ax->xbuff); 834 835 ax->tty = NULL; 836 } 837 838 /* Perform I/O control on an active ax25 channel. */ 839 static int mkiss_ioctl(struct tty_struct *tty, struct file *file, 840 unsigned int cmd, unsigned long arg) 841 { 842 struct mkiss *ax = mkiss_get(tty); 843 struct net_device *dev; 844 unsigned int tmp, err; 845 846 /* First make sure we're connected. */ 847 if (ax == NULL) 848 return -ENXIO; 849 dev = ax->dev; 850 851 switch (cmd) { 852 case SIOCGIFNAME: 853 err = copy_to_user((void __user *) arg, ax->dev->name, 854 strlen(ax->dev->name) + 1) ? -EFAULT : 0; 855 break; 856 857 case SIOCGIFENCAP: 858 err = put_user(4, (int __user *) arg); 859 break; 860 861 case SIOCSIFENCAP: 862 if (get_user(tmp, (int __user *) arg)) { 863 err = -EFAULT; 864 break; 865 } 866 867 ax->mode = tmp; 868 dev->addr_len = AX25_ADDR_LEN; 869 dev->hard_header_len = AX25_KISS_HEADER_LEN + 870 AX25_MAX_HEADER_LEN + 3; 871 dev->type = ARPHRD_AX25; 872 873 err = 0; 874 break; 875 876 case SIOCSIFHWADDR: { 877 char addr[AX25_ADDR_LEN]; 878 879 if (copy_from_user(&addr, 880 (void __user *) arg, AX25_ADDR_LEN)) { 881 err = -EFAULT; 882 break; 883 } 884 885 netif_tx_lock_bh(dev); 886 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN); 887 netif_tx_unlock_bh(dev); 888 889 err = 0; 890 break; 891 } 892 default: 893 err = -ENOIOCTLCMD; 894 } 895 896 mkiss_put(ax); 897 898 return err; 899 } 900 901 #ifdef CONFIG_COMPAT 902 static long mkiss_compat_ioctl(struct tty_struct *tty, struct file *file, 903 unsigned int cmd, unsigned long arg) 904 { 905 switch (cmd) { 906 case SIOCGIFNAME: 907 case SIOCGIFENCAP: 908 case SIOCSIFENCAP: 909 case SIOCSIFHWADDR: 910 return mkiss_ioctl(tty, file, cmd, 911 (unsigned long)compat_ptr(arg)); 912 } 913 914 return -ENOIOCTLCMD; 915 } 916 #endif 917 918 /* 919 * Handle the 'receiver data ready' interrupt. 920 * This function is called by the 'tty_io' module in the kernel when 921 * a block of data has been received, which can now be decapsulated 922 * and sent on to the AX.25 layer for further processing. 923 */ 924 static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp, 925 char *fp, int count) 926 { 927 struct mkiss *ax = mkiss_get(tty); 928 929 if (!ax) 930 return; 931 932 /* 933 * Argh! mtu change time! - costs us the packet part received 934 * at the change 935 */ 936 if (ax->mtu != ax->dev->mtu + 73) 937 ax_changedmtu(ax); 938 939 /* Read the characters out of the buffer */ 940 while (count--) { 941 if (fp != NULL && *fp++) { 942 if (!test_and_set_bit(AXF_ERROR, &ax->flags)) 943 ax->dev->stats.rx_errors++; 944 cp++; 945 continue; 946 } 947 948 kiss_unesc(ax, *cp++); 949 } 950 951 mkiss_put(ax); 952 tty_unthrottle(tty); 953 } 954 955 /* 956 * Called by the driver when there's room for more data. If we have 957 * more packets to send, we send them here. 958 */ 959 static void mkiss_write_wakeup(struct tty_struct *tty) 960 { 961 struct mkiss *ax = mkiss_get(tty); 962 int actual; 963 964 if (!ax) 965 return; 966 967 if (ax->xleft <= 0) { 968 /* Now serial buffer is almost free & we can start 969 * transmission of another packet 970 */ 971 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 972 973 netif_wake_queue(ax->dev); 974 goto out; 975 } 976 977 actual = tty->ops->write(tty, ax->xhead, ax->xleft); 978 ax->xleft -= actual; 979 ax->xhead += actual; 980 981 out: 982 mkiss_put(ax); 983 } 984 985 static struct tty_ldisc_ops ax_ldisc = { 986 .owner = THIS_MODULE, 987 .magic = TTY_LDISC_MAGIC, 988 .name = "mkiss", 989 .open = mkiss_open, 990 .close = mkiss_close, 991 .ioctl = mkiss_ioctl, 992 #ifdef CONFIG_COMPAT 993 .compat_ioctl = mkiss_compat_ioctl, 994 #endif 995 .receive_buf = mkiss_receive_buf, 996 .write_wakeup = mkiss_write_wakeup 997 }; 998 999 static const char banner[] __initconst = KERN_INFO \ 1000 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n"; 1001 static const char msg_regfail[] __initconst = KERN_ERR \ 1002 "mkiss: can't register line discipline (err = %d)\n"; 1003 1004 static int __init mkiss_init_driver(void) 1005 { 1006 int status; 1007 1008 printk(banner); 1009 1010 status = tty_register_ldisc(N_AX25, &ax_ldisc); 1011 if (status != 0) 1012 printk(msg_regfail, status); 1013 1014 return status; 1015 } 1016 1017 static const char msg_unregfail[] = KERN_ERR \ 1018 "mkiss: can't unregister line discipline (err = %d)\n"; 1019 1020 static void __exit mkiss_exit_driver(void) 1021 { 1022 int ret; 1023 1024 if ((ret = tty_unregister_ldisc(N_AX25))) 1025 printk(msg_unregfail, ret); 1026 } 1027 1028 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>"); 1029 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs"); 1030 module_param(crc_force, int, 0); 1031 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]"); 1032 MODULE_LICENSE("GPL"); 1033 MODULE_ALIAS_LDISC(N_AX25); 1034 1035 module_init(mkiss_init_driver); 1036 module_exit(mkiss_exit_driver); 1037