drivers/net/netconsole.c

   1 /*
   2  *  linux/drivers/net/netconsole.c
   3  *
   4  *  Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   5  *
   6  *  This file contains the implementation of an IRQ-safe, crash-safe
   7  *  kernel console implementation that outputs kernel messages to the
   8  *  network.
   9  *
  10  * Modification history:
  11  *
  12  * 2001-09-17    started by Ingo Molnar.
  13  * 2003-08-11    2.6 port by Matt Mackall
  14  *               simplified options
  15  *               generic card hooks
  16  *               works non-modular
  17  * 2003-09-07    rewritten with netpoll api
  18  */
  19
  20 /****************************************************************
  21  *      This program is free software; you can redistribute it and/or modify
  22  *      it under the terms of the GNU General Public License as published by
  23  *      the Free Software Foundation; either version 2, or (at your option)
  24  *      any later version.
  25  *
  26  *      This program is distributed in the hope that it will be useful,
  27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  *      GNU General Public License for more details.
  30  *
  31  *      You should have received a copy of the GNU General Public License
  32  *      along with this program; if not, write to the Free Software
  33  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  34  *
  35  ****************************************************************/
  36
  37 #include <linux/mm.h>
  38 #include <linux/init.h>
  39 #include <linux/module.h>
  40 #include <linux/slab.h>
  41 #include <linux/console.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/string.h>
  44 #include <linux/netpoll.h>
  45 #include <linux/inet.h>
  46 #include <linux/configfs.h>
  47
  48 MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
  49 MODULE_DESCRIPTION("Console driver for network interfaces");
  50 MODULE_LICENSE("GPL");
  51
  52 #define MAX_PARAM_LENGTH        256
  53 #define MAX_PRINT_CHUNK         1000
  54
  55 static char config[MAX_PARAM_LENGTH];
  56 module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
  57 MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
  58
  59 #ifndef MODULE
  60 static int __init option_setup(char *opt)
  61 {
  62         strlcpy(config, opt, MAX_PARAM_LENGTH);
  63         return 1;
  64 }
  65 __setup("netconsole=", option_setup);
  66 #endif  /* MODULE */
  67
  68 /* Linked list of all configured targets */
  69 static LIST_HEAD(target_list);
  70
  71 /* This needs to be a spinlock because write_msg() cannot sleep */
  72 static DEFINE_SPINLOCK(target_list_lock);
  73
  74 /**
  75  * struct netconsole_target - Represents a configured netconsole target.
  76  * @list:       Links this target into the target_list.
  77  * @item:       Links us into the configfs subsystem hierarchy.
  78  * @enabled:    On / off knob to enable / disable target.
  79  *              Visible from userspace (read-write).
  80  *              We maintain a strict 1:1 correspondence between this and
  81  *              whether the corresponding netpoll is active or inactive.
  82  *              Also, other parameters of a target may be modified at
  83  *              runtime only when it is disabled (enabled == 0).
  84  * @np:         The netpoll structure for this target.
  85  *              Contains the other userspace visible parameters:
  86  *              dev_name        (read-write)
  87  *              local_port      (read-write)
  88  *              remote_port     (read-write)
  89  *              local_ip        (read-write)
  90  *              remote_ip       (read-write)
  91  *              local_mac       (read-only)
  92  *              remote_mac      (read-write)
  93  */
  94 struct netconsole_target {
  95         struct list_head        list;
  96 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
  97         struct config_item      item;
  98 #endif
  99         int                     enabled;
 100         struct netpoll          np;
 101 };
 102
 103 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 104
 105 static struct configfs_subsystem netconsole_subsys;
 106
 107 static int __init dynamic_netconsole_init(void)
 108 {
 109         config_group_init(&netconsole_subsys.su_group);
 110         mutex_init(&netconsole_subsys.su_mutex);
 111         return configfs_register_subsystem(&netconsole_subsys);
 112 }
 113
 114 static void __exit dynamic_netconsole_exit(void)
 115 {
 116         configfs_unregister_subsystem(&netconsole_subsys);
 117 }
 118
 119 /*
 120  * Targets that were created by parsing the boot/module option string
 121  * do not exist in the configfs hierarchy (and have NULL names) and will
 122  * never go away, so make these a no-op for them.
 123  */
 124 static void netconsole_target_get(struct netconsole_target *nt)
 125 {
 126         if (config_item_name(&nt->item))
 127                 config_item_get(&nt->item);
 128 }
 129
 130 static void netconsole_target_put(struct netconsole_target *nt)
 131 {
 132         if (config_item_name(&nt->item))
 133                 config_item_put(&nt->item);
 134 }
 135
 136 #else   /* !CONFIG_NETCONSOLE_DYNAMIC */
 137
 138 static int __init dynamic_netconsole_init(void)
 139 {
 140         return 0;
 141 }
 142
 143 static void __exit dynamic_netconsole_exit(void)
 144 {
 145 }
 146
 147 /*
 148  * No danger of targets going away from under us when dynamic
 149  * reconfigurability is off.
 150  */
 151 static void netconsole_target_get(struct netconsole_target *nt)
 152 {
 153 }
 154
 155 static void netconsole_target_put(struct netconsole_target *nt)
 156 {
 157 }
 158
 159 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 160
 161 /* Allocate new target (from boot/module param) and setup netpoll for it */
 162 static struct netconsole_target *alloc_param_target(char *target_config)
 163 {
 164         int err = -ENOMEM;
 165         struct netconsole_target *nt;
 166
 167         /*
 168          * Allocate and initialize with defaults.
 169          * Note that these targets get their config_item fields zeroed-out.
 170          */
 171         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 172         if (!nt) {
 173                 printk(KERN_ERR "netconsole: failed to allocate memory\n");
 174                 goto fail;
 175         }
 176
 177         nt->np.name = "netconsole";
 178         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 179         nt->np.local_port = 6665;
 180         nt->np.remote_port = 6666;
 181         memset(nt->np.remote_mac, 0xff, ETH_ALEN);
 182
 183         /* Parse parameters and setup netpoll */
 184         err = netpoll_parse_options(&nt->np, target_config);
 185         if (err)
 186                 goto fail;
 187
 188         err = netpoll_setup(&nt->np);
 189         if (err)
 190                 goto fail;
 191
 192         nt->enabled = 1;
 193
 194         return nt;
 195
 196 fail:
 197         kfree(nt);
 198         return ERR_PTR(err);
 199 }
 200
 201 /* Cleanup netpoll for given target (from boot/module param) and free it */
 202 static void free_param_target(struct netconsole_target *nt)
 203 {
 204         netpoll_cleanup(&nt->np);
 205         kfree(nt);
 206 }
 207
 208 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 209
 210 /*
 211  * Our subsystem hierarchy is:
 212  *
 213  * /sys/kernel/config/netconsole/
 214  *                              |
 215  *                              <target>/
 216  *                              |       enabled
 217  *                              |       dev_name
 218  *                              |       local_port
 219  *                              |       remote_port
 220  *                              |       local_ip
 221  *                              |       remote_ip
 222  *                              |       local_mac
 223  *                              |       remote_mac
 224  *                              |
 225  *                              <target>/...
 226  */
 227
 228 struct netconsole_target_attr {
 229         struct configfs_attribute       attr;
 230         ssize_t                         (*show)(struct netconsole_target *nt,
 231                                                 char *buf);
 232         ssize_t                         (*store)(struct netconsole_target *nt,
 233                                                  const char *buf,
 234                                                  size_t count);
 235 };
 236
 237 static struct netconsole_target *to_target(struct config_item *item)
 238 {
 239         return item ?
 240                 container_of(item, struct netconsole_target, item) :
 241                 NULL;
 242 }
 243
 244 /*
 245  * Attribute operations for netconsole_target.
 246  */
 247
 248 static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
 249 {
 250         return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
 251 }
 252
 253 static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
 254 {
 255         return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
 256 }
 257
 258 static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
 259 {
 260         return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
 261 }
 262
 263 static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
 264 {
 265         return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
 266 }
 267
 268 static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
 269 {
 270         return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
 271 }
 272
 273 static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
 274 {
 275         return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
 276 }
 277
 278 static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
 279 {
 280         struct net_device *dev = nt->np.dev;
 281         static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 282
 283         return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
 284 }
 285
 286 static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
 287 {
 288         return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
 289 }
 290
 291 /*
 292  * This one is special -- targets created through the configfs interface
 293  * are not enabled (and the corresponding netpoll activated) by default.
 294  * The user is expected to set the desired parameters first (which
 295  * would enable him to dynamically add new netpoll targets for new
 296  * network interfaces as and when they come up).
 297  */
 298 static ssize_t store_enabled(struct netconsole_target *nt,
 299                              const char *buf,
 300                              size_t count)
 301 {
 302         int enabled;
 303         int err;
 304
 305         err = kstrtoint(buf, 10, &enabled);
 306         if (err < 0)
 307                 return err;
 308         if (enabled < 0 || enabled > 1)
 309                 return -EINVAL;
 310
 311         if (enabled) {  /* 1 */
 312
 313                 /*
 314                  * Skip netpoll_parse_options() -- all the attributes are
 315                  * already configured via configfs. Just print them out.
 316                  */
 317                 netpoll_print_options(&nt->np);
 318
 319                 err = netpoll_setup(&nt->np);
 320                 if (err)
 321                         return err;
 322
 323                 printk(KERN_INFO "netconsole: network logging started\n");
 324
 325         } else {        /* 0 */
 326                 netpoll_cleanup(&nt->np);
 327         }
 328
 329         nt->enabled = enabled;
 330
 331         return strnlen(buf, count);
 332 }
 333
 334 static ssize_t store_dev_name(struct netconsole_target *nt,
 335                               const char *buf,
 336                               size_t count)
 337 {
 338         size_t len;
 339
 340         if (nt->enabled) {
 341                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 342                                 "disable to update parameters\n",
 343                                 config_item_name(&nt->item));
 344                 return -EINVAL;
 345         }
 346
 347         strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
 348
 349         /* Get rid of possible trailing newline from echo(1) */
 350         len = strnlen(nt->np.dev_name, IFNAMSIZ);
 351         if (nt->np.dev_name[len - 1] == '\n')
 352                 nt->np.dev_name[len - 1] = '\0';
 353
 354         return strnlen(buf, count);
 355 }
 356
 357 static ssize_t store_local_port(struct netconsole_target *nt,
 358                                 const char *buf,
 359                                 size_t count)
 360 {
 361         int rv;
 362
 363         if (nt->enabled) {
 364                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 365                                 "disable to update parameters\n",
 366                                 config_item_name(&nt->item));
 367                 return -EINVAL;
 368         }
 369
 370         rv = kstrtou16(buf, 10, &nt->np.local_port);
 371         if (rv < 0)
 372                 return rv;
 373         return strnlen(buf, count);
 374 }
 375
 376 static ssize_t store_remote_port(struct netconsole_target *nt,
 377                                  const char *buf,
 378                                  size_t count)
 379 {
 380         int rv;
 381
 382         if (nt->enabled) {
 383                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 384                                 "disable to update parameters\n",
 385                                 config_item_name(&nt->item));
 386                 return -EINVAL;
 387         }
 388
 389         rv = kstrtou16(buf, 10, &nt->np.remote_port);
 390         if (rv < 0)
 391                 return rv;
 392         return strnlen(buf, count);
 393 }
 394
 395 static ssize_t store_local_ip(struct netconsole_target *nt,
 396                               const char *buf,
 397                               size_t count)
 398 {
 399         if (nt->enabled) {
 400                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 401                                 "disable to update parameters\n",
 402                                 config_item_name(&nt->item));
 403                 return -EINVAL;
 404         }
 405
 406         nt->np.local_ip = in_aton(buf);
 407
 408         return strnlen(buf, count);
 409 }
 410
 411 static ssize_t store_remote_ip(struct netconsole_target *nt,
 412                                const char *buf,
 413                                size_t count)
 414 {
 415         if (nt->enabled) {
 416                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 417                                 "disable to update parameters\n",
 418                                 config_item_name(&nt->item));
 419                 return -EINVAL;
 420         }
 421
 422         nt->np.remote_ip = in_aton(buf);
 423
 424         return strnlen(buf, count);
 425 }
 426
 427 static ssize_t store_remote_mac(struct netconsole_target *nt,
 428                                 const char *buf,
 429                                 size_t count)
 430 {
 431         u8 remote_mac[ETH_ALEN];
 432         char *p = (char *) buf;
 433         int i;
 434
 435         if (nt->enabled) {
 436                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 437                                 "disable to update parameters\n",
 438                                 config_item_name(&nt->item));
 439                 return -EINVAL;
 440         }
 441
 442         for (i = 0; i < ETH_ALEN - 1; i++) {
 443                 remote_mac[i] = simple_strtoul(p, &p, 16);
 444                 if (*p != ':')
 445                         goto invalid;
 446                 p++;
 447         }
 448         remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
 449         if (*p && (*p != '\n'))
 450                 goto invalid;
 451
 452         memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
 453
 454         return strnlen(buf, count);
 455
 456 invalid:
 457         printk(KERN_ERR "netconsole: invalid input\n");
 458         return -EINVAL;
 459 }
 460
 461 /*
 462  * Attribute definitions for netconsole_target.
 463  */
 464
 465 #define NETCONSOLE_TARGET_ATTR_RO(_name)                                \
 466 static struct netconsole_target_attr netconsole_target_##_name =        \
 467         __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
 468
 469 #define NETCONSOLE_TARGET_ATTR_RW(_name)                                \
 470 static struct netconsole_target_attr netconsole_target_##_name =        \
 471         __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
 472
 473 NETCONSOLE_TARGET_ATTR_RW(enabled);
 474 NETCONSOLE_TARGET_ATTR_RW(dev_name);
 475 NETCONSOLE_TARGET_ATTR_RW(local_port);
 476 NETCONSOLE_TARGET_ATTR_RW(remote_port);
 477 NETCONSOLE_TARGET_ATTR_RW(local_ip);
 478 NETCONSOLE_TARGET_ATTR_RW(remote_ip);
 479 NETCONSOLE_TARGET_ATTR_RO(local_mac);
 480 NETCONSOLE_TARGET_ATTR_RW(remote_mac);
 481
 482 static struct configfs_attribute *netconsole_target_attrs[] = {
 483         &netconsole_target_enabled.attr,
 484         &netconsole_target_dev_name.attr,
 485         &netconsole_target_local_port.attr,
 486         &netconsole_target_remote_port.attr,
 487         &netconsole_target_local_ip.attr,
 488         &netconsole_target_remote_ip.attr,
 489         &netconsole_target_local_mac.attr,
 490         &netconsole_target_remote_mac.attr,
 491         NULL,
 492 };
 493
 494 /*
 495  * Item operations and type for netconsole_target.
 496  */
 497
 498 static void netconsole_target_release(struct config_item *item)
 499 {
 500         kfree(to_target(item));
 501 }
 502
 503 static ssize_t netconsole_target_attr_show(struct config_item *item,
 504                                            struct configfs_attribute *attr,
 505                                            char *buf)
 506 {
 507         ssize_t ret = -EINVAL;
 508         struct netconsole_target *nt = to_target(item);
 509         struct netconsole_target_attr *na =
 510                 container_of(attr, struct netconsole_target_attr, attr);
 511
 512         if (na->show)
 513                 ret = na->show(nt, buf);
 514
 515         return ret;
 516 }
 517
 518 static ssize_t netconsole_target_attr_store(struct config_item *item,
 519                                             struct configfs_attribute *attr,
 520                                             const char *buf,
 521                                             size_t count)
 522 {
 523         ssize_t ret = -EINVAL;
 524         struct netconsole_target *nt = to_target(item);
 525         struct netconsole_target_attr *na =
 526                 container_of(attr, struct netconsole_target_attr, attr);
 527
 528         if (na->store)
 529                 ret = na->store(nt, buf, count);
 530
 531         return ret;
 532 }
 533
 534 static struct configfs_item_operations netconsole_target_item_ops = {
 535         .release                = netconsole_target_release,
 536         .show_attribute         = netconsole_target_attr_show,
 537         .store_attribute        = netconsole_target_attr_store,
 538 };
 539
 540 static struct config_item_type netconsole_target_type = {
 541         .ct_attrs               = netconsole_target_attrs,
 542         .ct_item_ops            = &netconsole_target_item_ops,
 543         .ct_owner               = THIS_MODULE,
 544 };
 545
 546 /*
 547  * Group operations and type for netconsole_subsys.
 548  */
 549
 550 static struct config_item *make_netconsole_target(struct config_group *group,
 551                                                   const char *name)
 552 {
 553         unsigned long flags;
 554         struct netconsole_target *nt;
 555
 556         /*
 557          * Allocate and initialize with defaults.
 558          * Target is disabled at creation (enabled == 0).
 559          */
 560         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 561         if (!nt) {
 562                 printk(KERN_ERR "netconsole: failed to allocate memory\n");
 563                 return ERR_PTR(-ENOMEM);
 564         }
 565
 566         nt->np.name = "netconsole";
 567         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 568         nt->np.local_port = 6665;
 569         nt->np.remote_port = 6666;
 570         memset(nt->np.remote_mac, 0xff, ETH_ALEN);
 571
 572         /* Initialize the config_item member */
 573         config_item_init_type_name(&nt->item, name, &netconsole_target_type);
 574
 575         /* Adding, but it is disabled */
 576         spin_lock_irqsave(&target_list_lock, flags);
 577         list_add(&nt->list, &target_list);
 578         spin_unlock_irqrestore(&target_list_lock, flags);
 579
 580         return &nt->item;
 581 }
 582
 583 static void drop_netconsole_target(struct config_group *group,
 584                                    struct config_item *item)
 585 {
 586         unsigned long flags;
 587         struct netconsole_target *nt = to_target(item);
 588
 589         spin_lock_irqsave(&target_list_lock, flags);
 590         list_del(&nt->list);
 591         spin_unlock_irqrestore(&target_list_lock, flags);
 592
 593         /*
 594          * The target may have never been enabled, or was manually disabled
 595          * before being removed so netpoll may have already been cleaned up.
 596          */
 597         if (nt->enabled)
 598                 netpoll_cleanup(&nt->np);
 599
 600         config_item_put(&nt->item);
 601 }
 602
 603 static struct configfs_group_operations netconsole_subsys_group_ops = {
 604         .make_item      = make_netconsole_target,
 605         .drop_item      = drop_netconsole_target,
 606 };
 607
 608 static struct config_item_type netconsole_subsys_type = {
 609         .ct_group_ops   = &netconsole_subsys_group_ops,
 610         .ct_owner       = THIS_MODULE,
 611 };
 612
 613 /* The netconsole configfs subsystem */
 614 static struct configfs_subsystem netconsole_subsys = {
 615         .su_group       = {
 616                 .cg_item        = {
 617                         .ci_namebuf     = "netconsole",
 618                         .ci_type        = &netconsole_subsys_type,
 619                 },
 620         },
 621 };
 622
 623 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 624
 625 /* Handle network interface device notifications */
 626 static int netconsole_netdev_event(struct notifier_block *this,
 627                                    unsigned long event,
 628                                    void *ptr)
 629 {
 630         unsigned long flags;
 631         struct netconsole_target *nt;
 632         struct net_device *dev = ptr;
 633         bool stopped = false;
 634
 635         if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
 636               event == NETDEV_BONDING_DESLAVE || event == NETDEV_GOING_DOWN))
 637                 goto done;
 638
 639         spin_lock_irqsave(&target_list_lock, flags);
 640 restart:
 641         list_for_each_entry(nt, &target_list, list) {
 642                 netconsole_target_get(nt);
 643                 if (nt->np.dev == dev) {
 644                         switch (event) {
 645                         case NETDEV_CHANGENAME:
 646                                 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
 647                                 break;
 648                         case NETDEV_UNREGISTER:
 649                                 /*
 650                                  * rtnl_lock already held
 651                                  */
 652                                 if (nt->np.dev) {
 653                                         spin_unlock_irqrestore(
 654                                                               &target_list_lock,
 655                                                               flags);
 656                                         __netpoll_cleanup(&nt->np);
 657                                         spin_lock_irqsave(&target_list_lock,
 658                                                           flags);
 659                                         dev_put(nt->np.dev);
 660                                         nt->np.dev = NULL;
 661                                         netconsole_target_put(nt);
 662                                         goto restart;
 663                                 }
 664                                 /* Fall through */
 665                         case NETDEV_GOING_DOWN:
 666                         case NETDEV_BONDING_DESLAVE:
 667                                 nt->enabled = 0;
 668                                 stopped = true;
 669                                 break;
 670                         }
 671                 }
 672                 netconsole_target_put(nt);
 673         }
 674         spin_unlock_irqrestore(&target_list_lock, flags);
 675         if (stopped && (event == NETDEV_UNREGISTER || event == NETDEV_BONDING_DESLAVE))
 676                 printk(KERN_INFO "netconsole: network logging stopped on "
 677                         "interface %s as it %s\n",  dev->name,
 678                         event == NETDEV_UNREGISTER ? "unregistered" : "released slaves");
 679
 680 done:
 681         return NOTIFY_DONE;
 682 }
 683
 684 static struct notifier_block netconsole_netdev_notifier = {
 685         .notifier_call  = netconsole_netdev_event,
 686 };
 687
 688 static void write_msg(struct console *con, const char *msg, unsigned int len)
 689 {
 690         int frag, left;
 691         unsigned long flags;
 692         struct netconsole_target *nt;
 693         const char *tmp;
 694
 695         /* Avoid taking lock and disabling interrupts unnecessarily */
 696         if (list_empty(&target_list))
 697                 return;
 698
 699         spin_lock_irqsave(&target_list_lock, flags);
 700         list_for_each_entry(nt, &target_list, list) {
 701                 netconsole_target_get(nt);
 702                 if (nt->enabled && netif_running(nt->np.dev)) {
 703                         /*
 704                          * We nest this inside the for-each-target loop above
 705                          * so that we're able to get as much logging out to
 706                          * at least one target if we die inside here, instead
 707                          * of unnecessarily keeping all targets in lock-step.
 708                          */
 709                         tmp = msg;
 710                         for (left = len; left;) {
 711                                 frag = min(left, MAX_PRINT_CHUNK);
 712                                 netpoll_send_udp(&nt->np, tmp, frag);
 713                                 tmp += frag;
 714                                 left -= frag;
 715                         }
 716                 }
 717                 netconsole_target_put(nt);
 718         }
 719         spin_unlock_irqrestore(&target_list_lock, flags);
 720 }
 721
 722 static struct console netconsole = {
 723         .name   = "netcon",
 724         .flags  = CON_ENABLED,
 725         .write  = write_msg,
 726 };
 727
 728 static int __init init_netconsole(void)
 729 {
 730         int err;
 731         struct netconsole_target *nt, *tmp;
 732         unsigned long flags;
 733         char *target_config;
 734         char *input = config;
 735
 736         if (strnlen(input, MAX_PARAM_LENGTH)) {
 737                 while ((target_config = strsep(&input, ";"))) {
 738                         nt = alloc_param_target(target_config);
 739                         if (IS_ERR(nt)) {
 740                                 err = PTR_ERR(nt);
 741                                 goto fail;
 742                         }
 743                         /* Dump existing printks when we register */
 744                         netconsole.flags |= CON_PRINTBUFFER;
 745
 746                         spin_lock_irqsave(&target_list_lock, flags);
 747                         list_add(&nt->list, &target_list);
 748                         spin_unlock_irqrestore(&target_list_lock, flags);
 749                 }
 750         }
 751
 752         err = register_netdevice_notifier(&netconsole_netdev_notifier);
 753         if (err)
 754                 goto fail;
 755
 756         err = dynamic_netconsole_init();
 757         if (err)
 758                 goto undonotifier;
 759
 760         register_console(&netconsole);
 761         printk(KERN_INFO "netconsole: network logging started\n");
 762
 763         return err;
 764
 765 undonotifier:
 766         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 767
 768 fail:
 769         printk(KERN_ERR "netconsole: cleaning up\n");
 770
 771         /*
 772          * Remove all targets and destroy them (only targets created
 773          * from the boot/module option exist here). Skipping the list
 774          * lock is safe here, and netpoll_cleanup() will sleep.
 775          */
 776         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 777                 list_del(&nt->list);
 778                 free_param_target(nt);
 779         }
 780
 781         return err;
 782 }
 783
 784 static void __exit cleanup_netconsole(void)
 785 {
 786         struct netconsole_target *nt, *tmp;
 787
 788         unregister_console(&netconsole);
 789         dynamic_netconsole_exit();
 790         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 791
 792         /*
 793          * Targets created via configfs pin references on our module
 794          * and would first be rmdir(2)'ed from userspace. We reach
 795          * here only when they are already destroyed, and only those
 796          * created from the boot/module option are left, so remove and
 797          * destroy them. Skipping the list lock is safe here, and
 798          * netpoll_cleanup() will sleep.
 799          */
 800         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 801                 list_del(&nt->list);
 802                 free_param_target(nt);
 803         }
 804 }
 805
 806 module_init(init_netconsole);
 807 module_exit(cleanup_netconsole);