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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  38
  39 #include <linux/mm.h>
  40 #include <linux/init.h>
  41 #include <linux/module.h>
  42 #include <linux/slab.h>
  43 #include <linux/console.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/kernel.h>
  46 #include <linux/string.h>
  47 #include <linux/netpoll.h>
  48 #include <linux/inet.h>
  49 #include <linux/configfs.h>
  50 #include <linux/etherdevice.h>
  51
  52 MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
  53 MODULE_DESCRIPTION("Console driver for network interfaces");
  54 MODULE_LICENSE("GPL");
  55
  56 #define MAX_PARAM_LENGTH        256
  57 #define MAX_PRINT_CHUNK         1000
  58
  59 static char config[MAX_PARAM_LENGTH];
  60 module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
  61 MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
  62
  63 static bool oops_only = false;
  64 module_param(oops_only, bool, 0600);
  65 MODULE_PARM_DESC(oops_only, "Only log oops messages");
  66
  67 #ifndef MODULE
  68 static int __init option_setup(char *opt)
  69 {
  70         strlcpy(config, opt, MAX_PARAM_LENGTH);
  71         return 1;
  72 }
  73 __setup("netconsole=", option_setup);
  74 #endif  /* MODULE */
  75
  76 /* Linked list of all configured targets */
  77 static LIST_HEAD(target_list);
  78
  79 /* This needs to be a spinlock because write_msg() cannot sleep */
  80 static DEFINE_SPINLOCK(target_list_lock);
  81
  82 /**
  83  * struct netconsole_target - Represents a configured netconsole target.
  84  * @list:       Links this target into the target_list.
  85  * @item:       Links us into the configfs subsystem hierarchy.
  86  * @enabled:    On / off knob to enable / disable target.
  87  *              Visible from userspace (read-write).
  88  *              We maintain a strict 1:1 correspondence between this and
  89  *              whether the corresponding netpoll is active or inactive.
  90  *              Also, other parameters of a target may be modified at
  91  *              runtime only when it is disabled (enabled == 0).
  92  * @np:         The netpoll structure for this target.
  93  *              Contains the other userspace visible parameters:
  94  *              dev_name        (read-write)
  95  *              local_port      (read-write)
  96  *              remote_port     (read-write)
  97  *              local_ip        (read-write)
  98  *              remote_ip       (read-write)
  99  *              local_mac       (read-only)
 100  *              remote_mac      (read-write)
 101  */
 102 struct netconsole_target {
 103         struct list_head        list;
 104 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 105         struct config_item      item;
 106 #endif
 107         bool                    enabled;
 108         struct netpoll          np;
 109 };
 110
 111 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 112
 113 static struct configfs_subsystem netconsole_subsys;
 114 static DEFINE_MUTEX(dynamic_netconsole_mutex);
 115
 116 static int __init dynamic_netconsole_init(void)
 117 {
 118         config_group_init(&netconsole_subsys.su_group);
 119         mutex_init(&netconsole_subsys.su_mutex);
 120         return configfs_register_subsystem(&netconsole_subsys);
 121 }
 122
 123 static void __exit dynamic_netconsole_exit(void)
 124 {
 125         configfs_unregister_subsystem(&netconsole_subsys);
 126 }
 127
 128 /*
 129  * Targets that were created by parsing the boot/module option string
 130  * do not exist in the configfs hierarchy (and have NULL names) and will
 131  * never go away, so make these a no-op for them.
 132  */
 133 static void netconsole_target_get(struct netconsole_target *nt)
 134 {
 135         if (config_item_name(&nt->item))
 136                 config_item_get(&nt->item);
 137 }
 138
 139 static void netconsole_target_put(struct netconsole_target *nt)
 140 {
 141         if (config_item_name(&nt->item))
 142                 config_item_put(&nt->item);
 143 }
 144
 145 #else   /* !CONFIG_NETCONSOLE_DYNAMIC */
 146
 147 static int __init dynamic_netconsole_init(void)
 148 {
 149         return 0;
 150 }
 151
 152 static void __exit dynamic_netconsole_exit(void)
 153 {
 154 }
 155
 156 /*
 157  * No danger of targets going away from under us when dynamic
 158  * reconfigurability is off.
 159  */
 160 static void netconsole_target_get(struct netconsole_target *nt)
 161 {
 162 }
 163
 164 static void netconsole_target_put(struct netconsole_target *nt)
 165 {
 166 }
 167
 168 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 169
 170 /* Allocate new target (from boot/module param) and setup netpoll for it */
 171 static struct netconsole_target *alloc_param_target(char *target_config)
 172 {
 173         int err = -ENOMEM;
 174         struct netconsole_target *nt;
 175
 176         /*
 177          * Allocate and initialize with defaults.
 178          * Note that these targets get their config_item fields zeroed-out.
 179          */
 180         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 181         if (!nt)
 182                 goto fail;
 183
 184         nt->np.name = "netconsole";
 185         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 186         nt->np.local_port = 6665;
 187         nt->np.remote_port = 6666;
 188         eth_broadcast_addr(nt->np.remote_mac);
 189
 190         /* Parse parameters and setup netpoll */
 191         err = netpoll_parse_options(&nt->np, target_config);
 192         if (err)
 193                 goto fail;
 194
 195         err = netpoll_setup(&nt->np);
 196         if (err)
 197                 goto fail;
 198
 199         nt->enabled = true;
 200
 201         return nt;
 202
 203 fail:
 204         kfree(nt);
 205         return ERR_PTR(err);
 206 }
 207
 208 /* Cleanup netpoll for given target (from boot/module param) and free it */
 209 static void free_param_target(struct netconsole_target *nt)
 210 {
 211         netpoll_cleanup(&nt->np);
 212         kfree(nt);
 213 }
 214
 215 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 216
 217 /*
 218  * Our subsystem hierarchy is:
 219  *
 220  * /sys/kernel/config/netconsole/
 221  *                              |
 222  *                              <target>/
 223  *                              |       enabled
 224  *                              |       dev_name
 225  *                              |       local_port
 226  *                              |       remote_port
 227  *                              |       local_ip
 228  *                              |       remote_ip
 229  *                              |       local_mac
 230  *                              |       remote_mac
 231  *                              |
 232  *                              <target>/...
 233  */
 234
 235 struct netconsole_target_attr {
 236         struct configfs_attribute       attr;
 237         ssize_t                         (*show)(struct netconsole_target *nt,
 238                                                 char *buf);
 239         ssize_t                         (*store)(struct netconsole_target *nt,
 240                                                  const char *buf,
 241                                                  size_t count);
 242 };
 243
 244 static struct netconsole_target *to_target(struct config_item *item)
 245 {
 246         return item ?
 247                 container_of(item, struct netconsole_target, item) :
 248                 NULL;
 249 }
 250
 251 /*
 252  * Attribute operations for netconsole_target.
 253  */
 254
 255 static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
 256 {
 257         return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
 258 }
 259
 260 static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
 261 {
 262         return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
 263 }
 264
 265 static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
 266 {
 267         return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
 268 }
 269
 270 static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
 271 {
 272         return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
 273 }
 274
 275 static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
 276 {
 277         if (nt->np.ipv6)
 278                 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
 279         else
 280                 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
 281 }
 282
 283 static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
 284 {
 285         if (nt->np.ipv6)
 286                 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
 287         else
 288                 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
 289 }
 290
 291 static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
 292 {
 293         struct net_device *dev = nt->np.dev;
 294         static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 295
 296         return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
 297 }
 298
 299 static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
 300 {
 301         return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
 302 }
 303
 304 /*
 305  * This one is special -- targets created through the configfs interface
 306  * are not enabled (and the corresponding netpoll activated) by default.
 307  * The user is expected to set the desired parameters first (which
 308  * would enable him to dynamically add new netpoll targets for new
 309  * network interfaces as and when they come up).
 310  */
 311 static ssize_t store_enabled(struct netconsole_target *nt,
 312                              const char *buf,
 313                              size_t count)
 314 {
 315         unsigned long flags;
 316         int enabled;
 317         int err;
 318
 319         err = kstrtoint(buf, 10, &enabled);
 320         if (err < 0)
 321                 return err;
 322         if (enabled < 0 || enabled > 1)
 323                 return -EINVAL;
 324         if ((bool)enabled == nt->enabled) {
 325                 pr_info("network logging has already %s\n",
 326                         nt->enabled ? "started" : "stopped");
 327                 return -EINVAL;
 328         }
 329
 330         if (enabled) {  /* true */
 331                 /*
 332                  * Skip netpoll_parse_options() -- all the attributes are
 333                  * already configured via configfs. Just print them out.
 334                  */
 335                 netpoll_print_options(&nt->np);
 336
 337                 err = netpoll_setup(&nt->np);
 338                 if (err)
 339                         return err;
 340
 341                 pr_info("netconsole: network logging started\n");
 342         } else {        /* false */
 343                 /* We need to disable the netconsole before cleaning it up
 344                  * otherwise we might end up in write_msg() with
 345                  * nt->np.dev == NULL and nt->enabled == true
 346                  */
 347                 spin_lock_irqsave(&target_list_lock, flags);
 348                 nt->enabled = false;
 349                 spin_unlock_irqrestore(&target_list_lock, flags);
 350                 netpoll_cleanup(&nt->np);
 351         }
 352
 353         nt->enabled = enabled;
 354
 355         return strnlen(buf, count);
 356 }
 357
 358 static ssize_t store_dev_name(struct netconsole_target *nt,
 359                               const char *buf,
 360                               size_t count)
 361 {
 362         size_t len;
 363
 364         if (nt->enabled) {
 365                 pr_err("target (%s) is enabled, disable to update parameters\n",
 366                        config_item_name(&nt->item));
 367                 return -EINVAL;
 368         }
 369
 370         strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
 371
 372         /* Get rid of possible trailing newline from echo(1) */
 373         len = strnlen(nt->np.dev_name, IFNAMSIZ);
 374         if (nt->np.dev_name[len - 1] == '\n')
 375                 nt->np.dev_name[len - 1] = '\0';
 376
 377         return strnlen(buf, count);
 378 }
 379
 380 static ssize_t store_local_port(struct netconsole_target *nt,
 381                                 const char *buf,
 382                                 size_t count)
 383 {
 384         int rv;
 385
 386         if (nt->enabled) {
 387                 pr_err("target (%s) is enabled, disable to update parameters\n",
 388                        config_item_name(&nt->item));
 389                 return -EINVAL;
 390         }
 391
 392         rv = kstrtou16(buf, 10, &nt->np.local_port);
 393         if (rv < 0)
 394                 return rv;
 395         return strnlen(buf, count);
 396 }
 397
 398 static ssize_t store_remote_port(struct netconsole_target *nt,
 399                                  const char *buf,
 400                                  size_t count)
 401 {
 402         int rv;
 403
 404         if (nt->enabled) {
 405                 pr_err("target (%s) is enabled, disable to update parameters\n",
 406                        config_item_name(&nt->item));
 407                 return -EINVAL;
 408         }
 409
 410         rv = kstrtou16(buf, 10, &nt->np.remote_port);
 411         if (rv < 0)
 412                 return rv;
 413         return strnlen(buf, count);
 414 }
 415
 416 static ssize_t store_local_ip(struct netconsole_target *nt,
 417                               const char *buf,
 418                               size_t count)
 419 {
 420         if (nt->enabled) {
 421                 pr_err("target (%s) is enabled, disable to update parameters\n",
 422                        config_item_name(&nt->item));
 423                 return -EINVAL;
 424         }
 425
 426         if (strnchr(buf, count, ':')) {
 427                 const char *end;
 428                 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
 429                         if (*end && *end != '\n') {
 430                                 pr_err("invalid IPv6 address at: <%c>\n", *end);
 431                                 return -EINVAL;
 432                         }
 433                         nt->np.ipv6 = true;
 434                 } else
 435                         return -EINVAL;
 436         } else {
 437                 if (!nt->np.ipv6) {
 438                         nt->np.local_ip.ip = in_aton(buf);
 439                 } else
 440                         return -EINVAL;
 441         }
 442
 443         return strnlen(buf, count);
 444 }
 445
 446 static ssize_t store_remote_ip(struct netconsole_target *nt,
 447                                const char *buf,
 448                                size_t count)
 449 {
 450         if (nt->enabled) {
 451                 pr_err("target (%s) is enabled, disable to update parameters\n",
 452                        config_item_name(&nt->item));
 453                 return -EINVAL;
 454         }
 455
 456         if (strnchr(buf, count, ':')) {
 457                 const char *end;
 458                 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
 459                         if (*end && *end != '\n') {
 460                                 pr_err("invalid IPv6 address at: <%c>\n", *end);
 461                                 return -EINVAL;
 462                         }
 463                         nt->np.ipv6 = true;
 464                 } else
 465                         return -EINVAL;
 466         } else {
 467                 if (!nt->np.ipv6) {
 468                         nt->np.remote_ip.ip = in_aton(buf);
 469                 } else
 470                         return -EINVAL;
 471         }
 472
 473         return strnlen(buf, count);
 474 }
 475
 476 static ssize_t store_remote_mac(struct netconsole_target *nt,
 477                                 const char *buf,
 478                                 size_t count)
 479 {
 480         u8 remote_mac[ETH_ALEN];
 481
 482         if (nt->enabled) {
 483                 pr_err("target (%s) is enabled, disable to update parameters\n",
 484                        config_item_name(&nt->item));
 485                 return -EINVAL;
 486         }
 487
 488         if (!mac_pton(buf, remote_mac))
 489                 return -EINVAL;
 490         if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
 491                 return -EINVAL;
 492         memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
 493
 494         return strnlen(buf, count);
 495 }
 496
 497 /*
 498  * Attribute definitions for netconsole_target.
 499  */
 500
 501 #define NETCONSOLE_TARGET_ATTR_RO(_name)                                \
 502 static struct netconsole_target_attr netconsole_target_##_name =        \
 503         __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
 504
 505 #define NETCONSOLE_TARGET_ATTR_RW(_name)                                \
 506 static struct netconsole_target_attr netconsole_target_##_name =        \
 507         __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
 508
 509 NETCONSOLE_TARGET_ATTR_RW(enabled);
 510 NETCONSOLE_TARGET_ATTR_RW(dev_name);
 511 NETCONSOLE_TARGET_ATTR_RW(local_port);
 512 NETCONSOLE_TARGET_ATTR_RW(remote_port);
 513 NETCONSOLE_TARGET_ATTR_RW(local_ip);
 514 NETCONSOLE_TARGET_ATTR_RW(remote_ip);
 515 NETCONSOLE_TARGET_ATTR_RO(local_mac);
 516 NETCONSOLE_TARGET_ATTR_RW(remote_mac);
 517
 518 static struct configfs_attribute *netconsole_target_attrs[] = {
 519         &netconsole_target_enabled.attr,
 520         &netconsole_target_dev_name.attr,
 521         &netconsole_target_local_port.attr,
 522         &netconsole_target_remote_port.attr,
 523         &netconsole_target_local_ip.attr,
 524         &netconsole_target_remote_ip.attr,
 525         &netconsole_target_local_mac.attr,
 526         &netconsole_target_remote_mac.attr,
 527         NULL,
 528 };
 529
 530 /*
 531  * Item operations and type for netconsole_target.
 532  */
 533
 534 static void netconsole_target_release(struct config_item *item)
 535 {
 536         kfree(to_target(item));
 537 }
 538
 539 static ssize_t netconsole_target_attr_show(struct config_item *item,
 540                                            struct configfs_attribute *attr,
 541                                            char *buf)
 542 {
 543         ssize_t ret = -EINVAL;
 544         struct netconsole_target *nt = to_target(item);
 545         struct netconsole_target_attr *na =
 546                 container_of(attr, struct netconsole_target_attr, attr);
 547
 548         if (na->show)
 549                 ret = na->show(nt, buf);
 550
 551         return ret;
 552 }
 553
 554 static ssize_t netconsole_target_attr_store(struct config_item *item,
 555                                             struct configfs_attribute *attr,
 556                                             const char *buf,
 557                                             size_t count)
 558 {
 559         ssize_t ret = -EINVAL;
 560         struct netconsole_target *nt = to_target(item);
 561         struct netconsole_target_attr *na =
 562                 container_of(attr, struct netconsole_target_attr, attr);
 563
 564         mutex_lock(&dynamic_netconsole_mutex);
 565         if (na->store)
 566                 ret = na->store(nt, buf, count);
 567         mutex_unlock(&dynamic_netconsole_mutex);
 568
 569         return ret;
 570 }
 571
 572 static struct configfs_item_operations netconsole_target_item_ops = {
 573         .release                = netconsole_target_release,
 574         .show_attribute         = netconsole_target_attr_show,
 575         .store_attribute        = netconsole_target_attr_store,
 576 };
 577
 578 static struct config_item_type netconsole_target_type = {
 579         .ct_attrs               = netconsole_target_attrs,
 580         .ct_item_ops            = &netconsole_target_item_ops,
 581         .ct_owner               = THIS_MODULE,
 582 };
 583
 584 /*
 585  * Group operations and type for netconsole_subsys.
 586  */
 587
 588 static struct config_item *make_netconsole_target(struct config_group *group,
 589                                                   const char *name)
 590 {
 591         unsigned long flags;
 592         struct netconsole_target *nt;
 593
 594         /*
 595          * Allocate and initialize with defaults.
 596          * Target is disabled at creation (!enabled).
 597          */
 598         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 599         if (!nt)
 600                 return ERR_PTR(-ENOMEM);
 601
 602         nt->np.name = "netconsole";
 603         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 604         nt->np.local_port = 6665;
 605         nt->np.remote_port = 6666;
 606         eth_broadcast_addr(nt->np.remote_mac);
 607
 608         /* Initialize the config_item member */
 609         config_item_init_type_name(&nt->item, name, &netconsole_target_type);
 610
 611         /* Adding, but it is disabled */
 612         spin_lock_irqsave(&target_list_lock, flags);
 613         list_add(&nt->list, &target_list);
 614         spin_unlock_irqrestore(&target_list_lock, flags);
 615
 616         return &nt->item;
 617 }
 618
 619 static void drop_netconsole_target(struct config_group *group,
 620                                    struct config_item *item)
 621 {
 622         unsigned long flags;
 623         struct netconsole_target *nt = to_target(item);
 624
 625         spin_lock_irqsave(&target_list_lock, flags);
 626         list_del(&nt->list);
 627         spin_unlock_irqrestore(&target_list_lock, flags);
 628
 629         /*
 630          * The target may have never been enabled, or was manually disabled
 631          * before being removed so netpoll may have already been cleaned up.
 632          */
 633         if (nt->enabled)
 634                 netpoll_cleanup(&nt->np);
 635
 636         config_item_put(&nt->item);
 637 }
 638
 639 static struct configfs_group_operations netconsole_subsys_group_ops = {
 640         .make_item      = make_netconsole_target,
 641         .drop_item      = drop_netconsole_target,
 642 };
 643
 644 static struct config_item_type netconsole_subsys_type = {
 645         .ct_group_ops   = &netconsole_subsys_group_ops,
 646         .ct_owner       = THIS_MODULE,
 647 };
 648
 649 /* The netconsole configfs subsystem */
 650 static struct configfs_subsystem netconsole_subsys = {
 651         .su_group       = {
 652                 .cg_item        = {
 653                         .ci_namebuf     = "netconsole",
 654                         .ci_type        = &netconsole_subsys_type,
 655                 },
 656         },
 657 };
 658
 659 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 660
 661 /* Handle network interface device notifications */
 662 static int netconsole_netdev_event(struct notifier_block *this,
 663                                    unsigned long event, void *ptr)
 664 {
 665         unsigned long flags;
 666         struct netconsole_target *nt;
 667         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 668         bool stopped = false;
 669
 670         if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
 671               event == NETDEV_RELEASE || event == NETDEV_JOIN))
 672                 goto done;
 673
 674         spin_lock_irqsave(&target_list_lock, flags);
 675 restart:
 676         list_for_each_entry(nt, &target_list, list) {
 677                 netconsole_target_get(nt);
 678                 if (nt->np.dev == dev) {
 679                         switch (event) {
 680                         case NETDEV_CHANGENAME:
 681                                 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
 682                                 break;
 683                         case NETDEV_RELEASE:
 684                         case NETDEV_JOIN:
 685                         case NETDEV_UNREGISTER:
 686                                 /* rtnl_lock already held
 687                                  * we might sleep in __netpoll_cleanup()
 688                                  */
 689                                 spin_unlock_irqrestore(&target_list_lock, flags);
 690
 691                                 __netpoll_cleanup(&nt->np);
 692
 693                                 spin_lock_irqsave(&target_list_lock, flags);
 694                                 dev_put(nt->np.dev);
 695                                 nt->np.dev = NULL;
 696                                 nt->enabled = false;
 697                                 stopped = true;
 698                                 netconsole_target_put(nt);
 699                                 goto restart;
 700                         }
 701                 }
 702                 netconsole_target_put(nt);
 703         }
 704         spin_unlock_irqrestore(&target_list_lock, flags);
 705         if (stopped) {
 706                 const char *msg = "had an event";
 707                 switch (event) {
 708                 case NETDEV_UNREGISTER:
 709                         msg = "unregistered";
 710                         break;
 711                 case NETDEV_RELEASE:
 712                         msg = "released slaves";
 713                         break;
 714                 case NETDEV_JOIN:
 715                         msg = "is joining a master device";
 716                         break;
 717                 }
 718                 pr_info("network logging stopped on interface %s as it %s\n",
 719                         dev->name, msg);
 720         }
 721
 722 done:
 723         return NOTIFY_DONE;
 724 }
 725
 726 static struct notifier_block netconsole_netdev_notifier = {
 727         .notifier_call  = netconsole_netdev_event,
 728 };
 729
 730 static void write_msg(struct console *con, const char *msg, unsigned int len)
 731 {
 732         int frag, left;
 733         unsigned long flags;
 734         struct netconsole_target *nt;
 735         const char *tmp;
 736
 737         if (oops_only && !oops_in_progress)
 738                 return;
 739         /* Avoid taking lock and disabling interrupts unnecessarily */
 740         if (list_empty(&target_list))
 741                 return;
 742
 743         spin_lock_irqsave(&target_list_lock, flags);
 744         list_for_each_entry(nt, &target_list, list) {
 745                 if (nt->enabled && netif_running(nt->np.dev)) {
 746                         /*
 747                          * We nest this inside the for-each-target loop above
 748                          * so that we're able to get as much logging out to
 749                          * at least one target if we die inside here, instead
 750                          * of unnecessarily keeping all targets in lock-step.
 751                          */
 752                         tmp = msg;
 753                         for (left = len; left;) {
 754                                 frag = min(left, MAX_PRINT_CHUNK);
 755                                 netpoll_send_udp(&nt->np, tmp, frag);
 756                                 tmp += frag;
 757                                 left -= frag;
 758                         }
 759                 }
 760         }
 761         spin_unlock_irqrestore(&target_list_lock, flags);
 762 }
 763
 764 static struct console netconsole = {
 765         .name   = "netcon",
 766         .flags  = CON_ENABLED,
 767         .write  = write_msg,
 768 };
 769
 770 static int __init init_netconsole(void)
 771 {
 772         int err;
 773         struct netconsole_target *nt, *tmp;
 774         unsigned long flags;
 775         char *target_config;
 776         char *input = config;
 777
 778         if (strnlen(input, MAX_PARAM_LENGTH)) {
 779                 while ((target_config = strsep(&input, ";"))) {
 780                         nt = alloc_param_target(target_config);
 781                         if (IS_ERR(nt)) {
 782                                 err = PTR_ERR(nt);
 783                                 goto fail;
 784                         }
 785                         /* Dump existing printks when we register */
 786                         netconsole.flags |= CON_PRINTBUFFER;
 787
 788                         spin_lock_irqsave(&target_list_lock, flags);
 789                         list_add(&nt->list, &target_list);
 790                         spin_unlock_irqrestore(&target_list_lock, flags);
 791                 }
 792         }
 793
 794         err = register_netdevice_notifier(&netconsole_netdev_notifier);
 795         if (err)
 796                 goto fail;
 797
 798         err = dynamic_netconsole_init();
 799         if (err)
 800                 goto undonotifier;
 801
 802         register_console(&netconsole);
 803         pr_info("network logging started\n");
 804
 805         return err;
 806
 807 undonotifier:
 808         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 809
 810 fail:
 811         pr_err("cleaning up\n");
 812
 813         /*
 814          * Remove all targets and destroy them (only targets created
 815          * from the boot/module option exist here). Skipping the list
 816          * lock is safe here, and netpoll_cleanup() will sleep.
 817          */
 818         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 819                 list_del(&nt->list);
 820                 free_param_target(nt);
 821         }
 822
 823         return err;
 824 }
 825
 826 static void __exit cleanup_netconsole(void)
 827 {
 828         struct netconsole_target *nt, *tmp;
 829
 830         unregister_console(&netconsole);
 831         dynamic_netconsole_exit();
 832         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 833
 834         /*
 835          * Targets created via configfs pin references on our module
 836          * and would first be rmdir(2)'ed from userspace. We reach
 837          * here only when they are already destroyed, and only those
 838          * created from the boot/module option are left, so remove and
 839          * destroy them. Skipping the list lock is safe here, and
 840          * netpoll_cleanup() will sleep.
 841          */
 842         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 843                 list_del(&nt->list);
 844                 free_param_target(nt);
 845         }
 846 }
 847
 848 /*
 849  * Use late_initcall to ensure netconsole is
 850  * initialized after network device driver if built-in.
 851  *
 852  * late_initcall() and module_init() are identical if built as module.
 853  */
 854 late_initcall(init_netconsole);
 855 module_exit(cleanup_netconsole);