1/* 2 * slcan.c - serial line CAN interface driver (using tty line discipline) 3 * 4 * This file is derived from linux/drivers/net/slip/slip.c 5 * 6 * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk> 7 * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org> 8 * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net> 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License as published by the 12 * Free Software Foundation; either version 2 of the License, or (at your 13 * option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License along 21 * with this program; if not, see http://www.gnu.org/licenses/gpl.html 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 33 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 34 * DAMAGE. 35 * 36 */ 37 38#include <linux/module.h> 39#include <linux/moduleparam.h> 40 41#include <linux/uaccess.h> 42#include <linux/bitops.h> 43#include <linux/string.h> 44#include <linux/tty.h> 45#include <linux/errno.h> 46#include <linux/netdevice.h> 47#include <linux/skbuff.h> 48#include <linux/rtnetlink.h> 49#include <linux/if_arp.h> 50#include <linux/if_ether.h> 51#include <linux/sched.h> 52#include <linux/delay.h> 53#include <linux/init.h> 54#include <linux/kernel.h> 55#include <linux/workqueue.h> 56#include <linux/can.h> 57#include <linux/can/skb.h> 58#include <linux/can/can-ml.h> 59 60MODULE_ALIAS_LDISC(N_SLCAN); 61MODULE_DESCRIPTION("serial line CAN interface"); 62MODULE_LICENSE("GPL"); 63MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>"); 64 65#define SLCAN_MAGIC 0x53CA 66 67static int maxdev = 10; /* MAX number of SLCAN channels; 68 This can be overridden with 69 insmod slcan.ko maxdev=nnn */ 70module_param(maxdev, int, 0); 71MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces"); 72 73/* maximum rx buffer len: extended CAN frame with timestamp */ 74#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1) 75 76#define SLC_CMD_LEN 1 77#define SLC_SFF_ID_LEN 3 78#define SLC_EFF_ID_LEN 8 79 80struct slcan { 81 int magic; 82 83 /* Various fields. */ 84 struct tty_struct *tty; /* ptr to TTY structure */ 85 struct net_device *dev; /* easy for intr handling */ 86 spinlock_t lock; 87 struct work_struct tx_work; /* Flushes transmit buffer */ 88 89 /* These are pointers to the malloc()ed frame buffers. */ 90 unsigned char rbuff[SLC_MTU]; /* receiver buffer */ 91 int rcount; /* received chars counter */ 92 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */ 93 unsigned char *xhead; /* pointer to next XMIT byte */ 94 int xleft; /* bytes left in XMIT queue */ 95 96 unsigned long flags; /* Flag values/ mode etc */ 97#define SLF_INUSE 0 /* Channel in use */ 98#define SLF_ERROR 1 /* Parity, etc. error */ 99}; 100 101static struct net_device **slcan_devs; 102 103 /************************************************************************ 104 * SLCAN ENCAPSULATION FORMAT * 105 ************************************************************************/ 106 107/* 108 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended 109 * frame format) a data length code (can_dlc) which can be from 0 to 8 110 * and up to <can_dlc> data bytes as payload. 111 * Additionally a CAN frame may become a remote transmission frame if the 112 * RTR-bit is set. This causes another ECU to send a CAN frame with the 113 * given can_id. 114 * 115 * The SLCAN ASCII representation of these different frame types is: 116 * <type> <id> <dlc> <data>* 117 * 118 * Extended frames (29 bit) are defined by capital characters in the type. 119 * RTR frames are defined as 'r' types - normal frames have 't' type: 120 * t => 11 bit data frame 121 * r => 11 bit RTR frame 122 * T => 29 bit data frame 123 * R => 29 bit RTR frame 124 * 125 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64). 126 * The <dlc> is a one byte ASCII number ('0' - '8') 127 * The <data> section has at much ASCII Hex bytes as defined by the <dlc> 128 * 129 * Examples: 130 * 131 * t1230 : can_id 0x123, can_dlc 0, no data 132 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33 133 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55 134 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request 135 * 136 */ 137 138 /************************************************************************ 139 * STANDARD SLCAN DECAPSULATION * 140 ************************************************************************/ 141 142/* Send one completely decapsulated can_frame to the network layer */ 143static void slc_bump(struct slcan *sl) 144{ 145 struct sk_buff *skb; 146 struct can_frame cf; 147 int i, tmp; 148 u32 tmpid; 149 char *cmd = sl->rbuff; 150 151 memset(&cf, 0, sizeof(cf)); 152 153 switch (*cmd) { 154 case 'r': 155 cf.can_id = CAN_RTR_FLAG; 156 fallthrough; 157 case 't': 158 /* store dlc ASCII value and terminate SFF CAN ID string */ 159 cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN]; 160 sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0; 161 /* point to payload data behind the dlc */ 162 cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1; 163 break; 164 case 'R': 165 cf.can_id = CAN_RTR_FLAG; 166 fallthrough; 167 case 'T': 168 cf.can_id |= CAN_EFF_FLAG; 169 /* store dlc ASCII value and terminate EFF CAN ID string */ 170 cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN]; 171 sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0; 172 /* point to payload data behind the dlc */ 173 cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1; 174 break; 175 default: 176 return; 177 } 178 179 if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid)) 180 return; 181 182 cf.can_id |= tmpid; 183 184 /* get can_dlc from sanitized ASCII value */ 185 if (cf.can_dlc >= '0' && cf.can_dlc < '9') 186 cf.can_dlc -= '0'; 187 else 188 return; 189 190 /* RTR frames may have a dlc > 0 but they never have any data bytes */ 191 if (!(cf.can_id & CAN_RTR_FLAG)) { 192 for (i = 0; i < cf.can_dlc; i++) { 193 tmp = hex_to_bin(*cmd++); 194 if (tmp < 0) 195 return; 196 cf.data[i] = (tmp << 4); 197 tmp = hex_to_bin(*cmd++); 198 if (tmp < 0) 199 return; 200 cf.data[i] |= tmp; 201 } 202 } 203 204 skb = dev_alloc_skb(sizeof(struct can_frame) + 205 sizeof(struct can_skb_priv)); 206 if (!skb) 207 return; 208 209 skb->dev = sl->dev; 210 skb->protocol = htons(ETH_P_CAN); 211 skb->pkt_type = PACKET_BROADCAST; 212 skb->ip_summed = CHECKSUM_UNNECESSARY; 213 214 can_skb_reserve(skb); 215 can_skb_prv(skb)->ifindex = sl->dev->ifindex; 216 can_skb_prv(skb)->skbcnt = 0; 217 218 skb_put_data(skb, &cf, sizeof(struct can_frame)); 219 220 sl->dev->stats.rx_packets++; 221 sl->dev->stats.rx_bytes += cf.can_dlc; 222 netif_rx_ni(skb); 223} 224 225/* parse tty input stream */ 226static void slcan_unesc(struct slcan *sl, unsigned char s) 227{ 228 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */ 229 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 230 (sl->rcount > 4)) { 231 slc_bump(sl); 232 } 233 sl->rcount = 0; 234 } else { 235 if (!test_bit(SLF_ERROR, &sl->flags)) { 236 if (sl->rcount < SLC_MTU) { 237 sl->rbuff[sl->rcount++] = s; 238 return; 239 } else { 240 sl->dev->stats.rx_over_errors++; 241 set_bit(SLF_ERROR, &sl->flags); 242 } 243 } 244 } 245} 246 247 /************************************************************************ 248 * STANDARD SLCAN ENCAPSULATION * 249 ************************************************************************/ 250 251/* Encapsulate one can_frame and stuff into a TTY queue. */ 252static void slc_encaps(struct slcan *sl, struct can_frame *cf) 253{ 254 int actual, i; 255 unsigned char *pos; 256 unsigned char *endpos; 257 canid_t id = cf->can_id; 258 259 pos = sl->xbuff; 260 261 if (cf->can_id & CAN_RTR_FLAG) 262 *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */ 263 else 264 *pos = 'T'; /* becomes 't' in standard frame format (SSF) */ 265 266 /* determine number of chars for the CAN-identifier */ 267 if (cf->can_id & CAN_EFF_FLAG) { 268 id &= CAN_EFF_MASK; 269 endpos = pos + SLC_EFF_ID_LEN; 270 } else { 271 *pos |= 0x20; /* convert R/T to lower case for SFF */ 272 id &= CAN_SFF_MASK; 273 endpos = pos + SLC_SFF_ID_LEN; 274 } 275 276 /* build 3 (SFF) or 8 (EFF) digit CAN identifier */ 277 pos++; 278 while (endpos >= pos) { 279 *endpos-- = hex_asc_upper[id & 0xf]; 280 id >>= 4; 281 } 282 283 pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN; 284 285 *pos++ = cf->can_dlc + '0'; 286 287 /* RTR frames may have a dlc > 0 but they never have any data bytes */ 288 if (!(cf->can_id & CAN_RTR_FLAG)) { 289 for (i = 0; i < cf->can_dlc; i++) 290 pos = hex_byte_pack_upper(pos, cf->data[i]); 291 } 292 293 *pos++ = '\r'; 294 295 /* Order of next two lines is *very* important. 296 * When we are sending a little amount of data, 297 * the transfer may be completed inside the ops->write() 298 * routine, because it's running with interrupts enabled. 299 * In this case we *never* got WRITE_WAKEUP event, 300 * if we did not request it before write operation. 301 * 14 Oct 1994 Dmitry Gorodchanin. 302 */ 303 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 304 actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff); 305 sl->xleft = (pos - sl->xbuff) - actual; 306 sl->xhead = sl->xbuff + actual; 307 sl->dev->stats.tx_bytes += cf->can_dlc; 308} 309 310/* Write out any remaining transmit buffer. Scheduled when tty is writable */ 311static void slcan_transmit(struct work_struct *work) 312{ 313 struct slcan *sl = container_of(work, struct slcan, tx_work); 314 int actual; 315 316 spin_lock_bh(&sl->lock); 317 /* First make sure we're connected. */ 318 if (!sl->tty || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) { 319 spin_unlock_bh(&sl->lock); 320 return; 321 } 322 323 if (sl->xleft <= 0) { 324 /* Now serial buffer is almost free & we can start 325 * transmission of another packet */ 326 sl->dev->stats.tx_packets++; 327 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 328 spin_unlock_bh(&sl->lock); 329 netif_wake_queue(sl->dev); 330 return; 331 } 332 333 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft); 334 sl->xleft -= actual; 335 sl->xhead += actual; 336 spin_unlock_bh(&sl->lock); 337} 338 339/* 340 * Called by the driver when there's room for more data. 341 * Schedule the transmit. 342 */ 343static void slcan_write_wakeup(struct tty_struct *tty) 344{ 345 struct slcan *sl; 346 347 rcu_read_lock(); 348 sl = rcu_dereference(tty->disc_data); 349 if (sl) 350 schedule_work(&sl->tx_work); 351 rcu_read_unlock(); 352} 353 354/* Send a can_frame to a TTY queue. */ 355static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev) 356{ 357 struct slcan *sl = netdev_priv(dev); 358 359 if (skb->len != CAN_MTU) 360 goto out; 361 362 spin_lock(&sl->lock); 363 if (!netif_running(dev)) { 364 spin_unlock(&sl->lock); 365 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name); 366 goto out; 367 } 368 if (sl->tty == NULL) { 369 spin_unlock(&sl->lock); 370 goto out; 371 } 372 373 netif_stop_queue(sl->dev); 374 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */ 375 spin_unlock(&sl->lock); 376 377out: 378 kfree_skb(skb); 379 return NETDEV_TX_OK; 380} 381 382 383/****************************************** 384 * Routines looking at netdevice side. 385 ******************************************/ 386 387/* Netdevice UP -> DOWN routine */ 388static int slc_close(struct net_device *dev) 389{ 390 struct slcan *sl = netdev_priv(dev); 391 392 spin_lock_bh(&sl->lock); 393 if (sl->tty) { 394 /* TTY discipline is running. */ 395 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 396 } 397 netif_stop_queue(dev); 398 sl->rcount = 0; 399 sl->xleft = 0; 400 spin_unlock_bh(&sl->lock); 401 402 return 0; 403} 404 405/* Netdevice DOWN -> UP routine */ 406static int slc_open(struct net_device *dev) 407{ 408 struct slcan *sl = netdev_priv(dev); 409 410 if (sl->tty == NULL) 411 return -ENODEV; 412 413 sl->flags &= (1 << SLF_INUSE); 414 netif_start_queue(dev); 415 return 0; 416} 417 418/* Hook the destructor so we can free slcan devs at the right point in time */ 419static void slc_free_netdev(struct net_device *dev) 420{ 421 int i = dev->base_addr; 422 423 slcan_devs[i] = NULL; 424} 425 426static int slcan_change_mtu(struct net_device *dev, int new_mtu) 427{ 428 return -EINVAL; 429} 430 431static const struct net_device_ops slc_netdev_ops = { 432 .ndo_open = slc_open, 433 .ndo_stop = slc_close, 434 .ndo_start_xmit = slc_xmit, 435 .ndo_change_mtu = slcan_change_mtu, 436}; 437 438static void slc_setup(struct net_device *dev) 439{ 440 dev->netdev_ops = &slc_netdev_ops; 441 dev->needs_free_netdev = true; 442 dev->priv_destructor = slc_free_netdev; 443 444 dev->hard_header_len = 0; 445 dev->addr_len = 0; 446 dev->tx_queue_len = 10; 447 448 dev->mtu = CAN_MTU; 449 dev->type = ARPHRD_CAN; 450 451 /* New-style flags. */ 452 dev->flags = IFF_NOARP; 453 dev->features = NETIF_F_HW_CSUM; 454} 455 456/****************************************** 457 Routines looking at TTY side. 458 ******************************************/ 459 460/* 461 * Handle the 'receiver data ready' interrupt. 462 * This function is called by the 'tty_io' module in the kernel when 463 * a block of SLCAN data has been received, which can now be decapsulated 464 * and sent on to some IP layer for further processing. This will not 465 * be re-entered while running but other ldisc functions may be called 466 * in parallel 467 */ 468 469static void slcan_receive_buf(struct tty_struct *tty, 470 const unsigned char *cp, char *fp, int count) 471{ 472 struct slcan *sl = (struct slcan *) tty->disc_data; 473 474 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) 475 return; 476 477 /* Read the characters out of the buffer */ 478 while (count--) { 479 if (fp && *fp++) { 480 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 481 sl->dev->stats.rx_errors++; 482 cp++; 483 continue; 484 } 485 slcan_unesc(sl, *cp++); 486 } 487} 488 489/************************************ 490 * slcan_open helper routines. 491 ************************************/ 492 493/* Collect hanged up channels */ 494static void slc_sync(void) 495{ 496 int i; 497 struct net_device *dev; 498 struct slcan *sl; 499 500 for (i = 0; i < maxdev; i++) { 501 dev = slcan_devs[i]; 502 if (dev == NULL) 503 break; 504 505 sl = netdev_priv(dev); 506 if (sl->tty) 507 continue; 508 if (dev->flags & IFF_UP) 509 dev_close(dev); 510 } 511} 512 513/* Find a free SLCAN channel, and link in this `tty' line. */ 514static struct slcan *slc_alloc(void) 515{ 516 int i; 517 char name[IFNAMSIZ]; 518 struct net_device *dev = NULL; 519 struct can_ml_priv *can_ml; 520 struct slcan *sl; 521 int size; 522 523 for (i = 0; i < maxdev; i++) { 524 dev = slcan_devs[i]; 525 if (dev == NULL) 526 break; 527 528 } 529 530 /* Sorry, too many, all slots in use */ 531 if (i >= maxdev) 532 return NULL; 533 534 sprintf(name, "slcan%d", i); 535 size = ALIGN(sizeof(*sl), NETDEV_ALIGN) + sizeof(struct can_ml_priv); 536 dev = alloc_netdev(size, name, NET_NAME_UNKNOWN, slc_setup); 537 if (!dev) 538 return NULL; 539 540 dev->base_addr = i; 541 sl = netdev_priv(dev); 542 can_ml = (void *)sl + ALIGN(sizeof(*sl), NETDEV_ALIGN); 543 can_set_ml_priv(dev, can_ml); 544 545 /* Initialize channel control data */ 546 sl->magic = SLCAN_MAGIC; 547 sl->dev = dev; 548 spin_lock_init(&sl->lock); 549 INIT_WORK(&sl->tx_work, slcan_transmit); 550 slcan_devs[i] = dev; 551 552 return sl; 553} 554 555/* 556 * Open the high-level part of the SLCAN channel. 557 * This function is called by the TTY module when the 558 * SLCAN line discipline is called for. Because we are 559 * sure the tty line exists, we only have to link it to 560 * a free SLCAN channel... 561 * 562 * Called in process context serialized from other ldisc calls. 563 */ 564 565static int slcan_open(struct tty_struct *tty) 566{ 567 struct slcan *sl; 568 int err; 569 570 if (!capable(CAP_NET_ADMIN)) 571 return -EPERM; 572 573 if (tty->ops->write == NULL) 574 return -EOPNOTSUPP; 575 576 /* RTnetlink lock is misused here to serialize concurrent 577 opens of slcan channels. There are better ways, but it is 578 the simplest one. 579 */ 580 rtnl_lock(); 581 582 /* Collect hanged up channels. */ 583 slc_sync(); 584 585 sl = tty->disc_data; 586 587 err = -EEXIST; 588 /* First make sure we're not already connected. */ 589 if (sl && sl->magic == SLCAN_MAGIC) 590 goto err_exit; 591 592 /* OK. Find a free SLCAN channel to use. */ 593 err = -ENFILE; 594 sl = slc_alloc(); 595 if (sl == NULL) 596 goto err_exit; 597 598 sl->tty = tty; 599 tty->disc_data = sl; 600 601 if (!test_bit(SLF_INUSE, &sl->flags)) { 602 /* Perform the low-level SLCAN initialization. */ 603 sl->rcount = 0; 604 sl->xleft = 0; 605 606 set_bit(SLF_INUSE, &sl->flags); 607 608 err = register_netdevice(sl->dev); 609 if (err) 610 goto err_free_chan; 611 } 612 613 /* Done. We have linked the TTY line to a channel. */ 614 rtnl_unlock(); 615 tty->receive_room = 65536; /* We don't flow control */ 616 617 /* TTY layer expects 0 on success */ 618 return 0; 619 620err_free_chan: 621 sl->tty = NULL; 622 tty->disc_data = NULL; 623 clear_bit(SLF_INUSE, &sl->flags); 624 slc_free_netdev(sl->dev); 625 /* do not call free_netdev before rtnl_unlock */ 626 rtnl_unlock(); 627 free_netdev(sl->dev); 628 return err; 629 630err_exit: 631 rtnl_unlock(); 632 633 /* Count references from TTY module */ 634 return err; 635} 636 637/* 638 * Close down a SLCAN channel. 639 * This means flushing out any pending queues, and then returning. This 640 * call is serialized against other ldisc functions. 641 * 642 * We also use this method for a hangup event. 643 */ 644 645static void slcan_close(struct tty_struct *tty) 646{ 647 struct slcan *sl = (struct slcan *) tty->disc_data; 648 649 /* First make sure we're connected. */ 650 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty) 651 return; 652 653 spin_lock_bh(&sl->lock); 654 rcu_assign_pointer(tty->disc_data, NULL); 655 sl->tty = NULL; 656 spin_unlock_bh(&sl->lock); 657 658 synchronize_rcu(); 659 flush_work(&sl->tx_work); 660 661 /* Flush network side */ 662 unregister_netdev(sl->dev); 663 /* This will complete via sl_free_netdev */ 664} 665 666static int slcan_hangup(struct tty_struct *tty) 667{ 668 slcan_close(tty); 669 return 0; 670} 671 672/* Perform I/O control on an active SLCAN channel. */ 673static int slcan_ioctl(struct tty_struct *tty, struct file *file, 674 unsigned int cmd, unsigned long arg) 675{ 676 struct slcan *sl = (struct slcan *) tty->disc_data; 677 unsigned int tmp; 678 679 /* First make sure we're connected. */ 680 if (!sl || sl->magic != SLCAN_MAGIC) 681 return -EINVAL; 682 683 switch (cmd) { 684 case SIOCGIFNAME: 685 tmp = strlen(sl->dev->name) + 1; 686 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 687 return -EFAULT; 688 return 0; 689 690 case SIOCSIFHWADDR: 691 return -EINVAL; 692 693 default: 694 return tty_mode_ioctl(tty, file, cmd, arg); 695 } 696} 697 698static struct tty_ldisc_ops slc_ldisc = { 699 .owner = THIS_MODULE, 700 .magic = TTY_LDISC_MAGIC, 701 .name = "slcan", 702 .open = slcan_open, 703 .close = slcan_close, 704 .hangup = slcan_hangup, 705 .ioctl = slcan_ioctl, 706 .receive_buf = slcan_receive_buf, 707 .write_wakeup = slcan_write_wakeup, 708}; 709 710static int __init slcan_init(void) 711{ 712 int status; 713 714 if (maxdev < 4) 715 maxdev = 4; /* Sanity */ 716 717 pr_info("slcan: serial line CAN interface driver\n"); 718 pr_info("slcan: %d dynamic interface channels.\n", maxdev); 719 720 slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL); 721 if (!slcan_devs) 722 return -ENOMEM; 723 724 /* Fill in our line protocol discipline, and register it */ 725 status = tty_register_ldisc(N_SLCAN, &slc_ldisc); 726 if (status) { 727 printk(KERN_ERR "slcan: can't register line discipline\n"); 728 kfree(slcan_devs); 729 } 730 return status; 731} 732 733static void __exit slcan_exit(void) 734{ 735 int i; 736 struct net_device *dev; 737 struct slcan *sl; 738 unsigned long timeout = jiffies + HZ; 739 int busy = 0; 740 741 if (slcan_devs == NULL) 742 return; 743 744 /* First of all: check for active disciplines and hangup them. 745 */ 746 do { 747 if (busy) 748 msleep_interruptible(100); 749 750 busy = 0; 751 for (i = 0; i < maxdev; i++) { 752 dev = slcan_devs[i]; 753 if (!dev) 754 continue; 755 sl = netdev_priv(dev); 756 spin_lock_bh(&sl->lock); 757 if (sl->tty) { 758 busy++; 759 tty_hangup(sl->tty); 760 } 761 spin_unlock_bh(&sl->lock); 762 } 763 } while (busy && time_before(jiffies, timeout)); 764 765 /* FIXME: hangup is async so we should wait when doing this second 766 phase */ 767 768 for (i = 0; i < maxdev; i++) { 769 dev = slcan_devs[i]; 770 if (!dev) 771 continue; 772 slcan_devs[i] = NULL; 773 774 sl = netdev_priv(dev); 775 if (sl->tty) { 776 printk(KERN_ERR "%s: tty discipline still running\n", 777 dev->name); 778 } 779 780 unregister_netdev(dev); 781 } 782 783 kfree(slcan_devs); 784 slcan_devs = NULL; 785 786 i = tty_unregister_ldisc(N_SLCAN); 787 if (i) 788 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i); 789} 790 791module_init(slcan_init); 792module_exit(slcan_exit); 793