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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
52MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
53MODULE_DESCRIPTION("Console driver for network interfaces");
54MODULE_LICENSE("GPL");
55
56#define MAX_PARAM_LENGTH 256
57#define MAX_PRINT_CHUNK 1000
58
59static char config[MAX_PARAM_LENGTH];
60module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
61MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
62
63static bool oops_only = false;
64module_param(oops_only, bool, 0600);
65MODULE_PARM_DESC(oops_only, "Only log oops messages");
66
67#ifndef MODULE
68static 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 */
77static LIST_HEAD(target_list);
78
79/* This needs to be a spinlock because write_msg() cannot sleep */
80static DEFINE_SPINLOCK(target_list_lock);
81
82/*
83 * Console driver for extended netconsoles. Registered on the first use to
84 * avoid unnecessarily enabling ext message formatting.
85 */
86static struct console netconsole_ext;
87
88/**
89 * struct netconsole_target - Represents a configured netconsole target.
90 * @list: Links this target into the target_list.
91 * @item: Links us into the configfs subsystem hierarchy.
92 * @enabled: On / off knob to enable / disable target.
93 * Visible from userspace (read-write).
94 * We maintain a strict 1:1 correspondence between this and
95 * whether the corresponding netpoll is active or inactive.
96 * Also, other parameters of a target may be modified at
97 * runtime only when it is disabled (enabled == 0).
98 * @np: The netpoll structure for this target.
99 * Contains the other userspace visible parameters:
100 * dev_name (read-write)
101 * local_port (read-write)
102 * remote_port (read-write)
103 * local_ip (read-write)
104 * remote_ip (read-write)
105 * local_mac (read-only)
106 * remote_mac (read-write)
107 */
108struct netconsole_target {
109 struct list_head list;
110#ifdef CONFIG_NETCONSOLE_DYNAMIC
111 struct config_item item;
112#endif
113 bool enabled;
114 bool extended;
115 struct netpoll np;
116};
117
118#ifdef CONFIG_NETCONSOLE_DYNAMIC
119
120static struct configfs_subsystem netconsole_subsys;
121static DEFINE_MUTEX(dynamic_netconsole_mutex);
122
123static int __init dynamic_netconsole_init(void)
124{
125 config_group_init(&netconsole_subsys.su_group);
126 mutex_init(&netconsole_subsys.su_mutex);
127 return configfs_register_subsystem(&netconsole_subsys);
128}
129
130static void __exit dynamic_netconsole_exit(void)
131{
132 configfs_unregister_subsystem(&netconsole_subsys);
133}
134
135/*
136 * Targets that were created by parsing the boot/module option string
137 * do not exist in the configfs hierarchy (and have NULL names) and will
138 * never go away, so make these a no-op for them.
139 */
140static void netconsole_target_get(struct netconsole_target *nt)
141{
142 if (config_item_name(&nt->item))
143 config_item_get(&nt->item);
144}
145
146static void netconsole_target_put(struct netconsole_target *nt)
147{
148 if (config_item_name(&nt->item))
149 config_item_put(&nt->item);
150}
151
152#else /* !CONFIG_NETCONSOLE_DYNAMIC */
153
154static int __init dynamic_netconsole_init(void)
155{
156 return 0;
157}
158
159static void __exit dynamic_netconsole_exit(void)
160{
161}
162
163/*
164 * No danger of targets going away from under us when dynamic
165 * reconfigurability is off.
166 */
167static void netconsole_target_get(struct netconsole_target *nt)
168{
169}
170
171static void netconsole_target_put(struct netconsole_target *nt)
172{
173}
174
175#endif /* CONFIG_NETCONSOLE_DYNAMIC */
176
177/* Allocate new target (from boot/module param) and setup netpoll for it */
178static struct netconsole_target *alloc_param_target(char *target_config)
179{
180 int err = -ENOMEM;
181 struct netconsole_target *nt;
182
183 /*
184 * Allocate and initialize with defaults.
185 * Note that these targets get their config_item fields zeroed-out.
186 */
187 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
188 if (!nt)
189 goto fail;
190
191 nt->np.name = "netconsole";
192 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
193 nt->np.local_port = 6665;
194 nt->np.remote_port = 6666;
195 eth_broadcast_addr(nt->np.remote_mac);
196
197 if (*target_config == '+') {
198 nt->extended = true;
199 target_config++;
200 }
201
202 /* Parse parameters and setup netpoll */
203 err = netpoll_parse_options(&nt->np, target_config);
204 if (err)
205 goto fail;
206
207 err = netpoll_setup(&nt->np);
208 if (err)
209 goto fail;
210
211 nt->enabled = true;
212
213 return nt;
214
215fail:
216 kfree(nt);
217 return ERR_PTR(err);
218}
219
220/* Cleanup netpoll for given target (from boot/module param) and free it */
221static void free_param_target(struct netconsole_target *nt)
222{
223 netpoll_cleanup(&nt->np);
224 kfree(nt);
225}
226
227#ifdef CONFIG_NETCONSOLE_DYNAMIC
228
229/*
230 * Our subsystem hierarchy is:
231 *
232 * /sys/kernel/config/netconsole/
233 * |
234 * <target>/
235 * | enabled
236 * | dev_name
237 * | local_port
238 * | remote_port
239 * | local_ip
240 * | remote_ip
241 * | local_mac
242 * | remote_mac
243 * |
244 * <target>/...
245 */
246
247static struct netconsole_target *to_target(struct config_item *item)
248{
249 return item ?
250 container_of(item, struct netconsole_target, item) :
251 NULL;
252}
253
254/*
255 * Attribute operations for netconsole_target.
256 */
257
258static ssize_t enabled_show(struct config_item *item, char *buf)
259{
260 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->enabled);
261}
262
263static ssize_t extended_show(struct config_item *item, char *buf)
264{
265 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->extended);
266}
267
268static ssize_t dev_name_show(struct config_item *item, char *buf)
269{
270 return snprintf(buf, PAGE_SIZE, "%s\n", to_target(item)->np.dev_name);
271}
272
273static ssize_t local_port_show(struct config_item *item, char *buf)
274{
275 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.local_port);
276}
277
278static ssize_t remote_port_show(struct config_item *item, char *buf)
279{
280 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.remote_port);
281}
282
283static ssize_t local_ip_show(struct config_item *item, char *buf)
284{
285 struct netconsole_target *nt = to_target(item);
286
287 if (nt->np.ipv6)
288 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
289 else
290 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
291}
292
293static ssize_t remote_ip_show(struct config_item *item, char *buf)
294{
295 struct netconsole_target *nt = to_target(item);
296
297 if (nt->np.ipv6)
298 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
299 else
300 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
301}
302
303static ssize_t local_mac_show(struct config_item *item, char *buf)
304{
305 struct net_device *dev = to_target(item)->np.dev;
306 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
307
308 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
309}
310
311static ssize_t remote_mac_show(struct config_item *item, char *buf)
312{
313 return snprintf(buf, PAGE_SIZE, "%pM\n", to_target(item)->np.remote_mac);
314}
315
316/*
317 * This one is special -- targets created through the configfs interface
318 * are not enabled (and the corresponding netpoll activated) by default.
319 * The user is expected to set the desired parameters first (which
320 * would enable him to dynamically add new netpoll targets for new
321 * network interfaces as and when they come up).
322 */
323static ssize_t enabled_store(struct config_item *item,
324 const char *buf, size_t count)
325{
326 struct netconsole_target *nt = to_target(item);
327 unsigned long flags;
328 int enabled;
329 int err;
330
331 mutex_lock(&dynamic_netconsole_mutex);
332 err = kstrtoint(buf, 10, &enabled);
333 if (err < 0)
334 goto out_unlock;
335
336 err = -EINVAL;
337 if (enabled < 0 || enabled > 1)
338 goto out_unlock;
339 if ((bool)enabled == nt->enabled) {
340 pr_info("network logging has already %s\n",
341 nt->enabled ? "started" : "stopped");
342 goto out_unlock;
343 }
344
345 if (enabled) { /* true */
346 if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
347 netconsole_ext.flags |= CON_ENABLED;
348 register_console(&netconsole_ext);
349 }
350
351 /*
352 * Skip netpoll_parse_options() -- all the attributes are
353 * already configured via configfs. Just print them out.
354 */
355 netpoll_print_options(&nt->np);
356
357 err = netpoll_setup(&nt->np);
358 if (err)
359 goto out_unlock;
360
361 pr_info("network logging started\n");
362 } else { /* false */
363 /* We need to disable the netconsole before cleaning it up
364 * otherwise we might end up in write_msg() with
365 * nt->np.dev == NULL and nt->enabled == true
366 */
367 spin_lock_irqsave(&target_list_lock, flags);
368 nt->enabled = false;
369 spin_unlock_irqrestore(&target_list_lock, flags);
370 netpoll_cleanup(&nt->np);
371 }
372
373 nt->enabled = enabled;
374
375 mutex_unlock(&dynamic_netconsole_mutex);
376 return strnlen(buf, count);
377out_unlock:
378 mutex_unlock(&dynamic_netconsole_mutex);
379 return err;
380}
381
382static ssize_t extended_store(struct config_item *item, const char *buf,
383 size_t count)
384{
385 struct netconsole_target *nt = to_target(item);
386 int extended;
387 int err;
388
389 mutex_lock(&dynamic_netconsole_mutex);
390 if (nt->enabled) {
391 pr_err("target (%s) is enabled, disable to update parameters\n",
392 config_item_name(&nt->item));
393 err = -EINVAL;
394 goto out_unlock;
395 }
396
397 err = kstrtoint(buf, 10, &extended);
398 if (err < 0)
399 goto out_unlock;
400 if (extended < 0 || extended > 1) {
401 err = -EINVAL;
402 goto out_unlock;
403 }
404
405 nt->extended = extended;
406
407 mutex_unlock(&dynamic_netconsole_mutex);
408 return strnlen(buf, count);
409out_unlock:
410 mutex_unlock(&dynamic_netconsole_mutex);
411 return err;
412}
413
414static ssize_t dev_name_store(struct config_item *item, const char *buf,
415 size_t count)
416{
417 struct netconsole_target *nt = to_target(item);
418 size_t len;
419
420 mutex_lock(&dynamic_netconsole_mutex);
421 if (nt->enabled) {
422 pr_err("target (%s) is enabled, disable to update parameters\n",
423 config_item_name(&nt->item));
424 mutex_unlock(&dynamic_netconsole_mutex);
425 return -EINVAL;
426 }
427
428 strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
429
430 /* Get rid of possible trailing newline from echo(1) */
431 len = strnlen(nt->np.dev_name, IFNAMSIZ);
432 if (nt->np.dev_name[len - 1] == '\n')
433 nt->np.dev_name[len - 1] = '\0';
434
435 mutex_unlock(&dynamic_netconsole_mutex);
436 return strnlen(buf, count);
437}
438
439static ssize_t local_port_store(struct config_item *item, const char *buf,
440 size_t count)
441{
442 struct netconsole_target *nt = to_target(item);
443 int rv = -EINVAL;
444
445 mutex_lock(&dynamic_netconsole_mutex);
446 if (nt->enabled) {
447 pr_err("target (%s) is enabled, disable to update parameters\n",
448 config_item_name(&nt->item));
449 goto out_unlock;
450 }
451
452 rv = kstrtou16(buf, 10, &nt->np.local_port);
453 if (rv < 0)
454 goto out_unlock;
455 mutex_unlock(&dynamic_netconsole_mutex);
456 return strnlen(buf, count);
457out_unlock:
458 mutex_unlock(&dynamic_netconsole_mutex);
459 return rv;
460}
461
462static ssize_t remote_port_store(struct config_item *item,
463 const char *buf, size_t count)
464{
465 struct netconsole_target *nt = to_target(item);
466 int rv = -EINVAL;
467
468 mutex_lock(&dynamic_netconsole_mutex);
469 if (nt->enabled) {
470 pr_err("target (%s) is enabled, disable to update parameters\n",
471 config_item_name(&nt->item));
472 goto out_unlock;
473 }
474
475 rv = kstrtou16(buf, 10, &nt->np.remote_port);
476 if (rv < 0)
477 goto out_unlock;
478 mutex_unlock(&dynamic_netconsole_mutex);
479 return strnlen(buf, count);
480out_unlock:
481 mutex_unlock(&dynamic_netconsole_mutex);
482 return rv;
483}
484
485static ssize_t local_ip_store(struct config_item *item, const char *buf,
486 size_t count)
487{
488 struct netconsole_target *nt = to_target(item);
489
490 mutex_lock(&dynamic_netconsole_mutex);
491 if (nt->enabled) {
492 pr_err("target (%s) is enabled, disable to update parameters\n",
493 config_item_name(&nt->item));
494 goto out_unlock;
495 }
496
497 if (strnchr(buf, count, ':')) {
498 const char *end;
499 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
500 if (*end && *end != '\n') {
501 pr_err("invalid IPv6 address at: <%c>\n", *end);
502 goto out_unlock;
503 }
504 nt->np.ipv6 = true;
505 } else
506 goto out_unlock;
507 } else {
508 if (!nt->np.ipv6) {
509 nt->np.local_ip.ip = in_aton(buf);
510 } else
511 goto out_unlock;
512 }
513
514 mutex_unlock(&dynamic_netconsole_mutex);
515 return strnlen(buf, count);
516out_unlock:
517 mutex_unlock(&dynamic_netconsole_mutex);
518 return -EINVAL;
519}
520
521static ssize_t remote_ip_store(struct config_item *item, const char *buf,
522 size_t count)
523{
524 struct netconsole_target *nt = to_target(item);
525
526 mutex_lock(&dynamic_netconsole_mutex);
527 if (nt->enabled) {
528 pr_err("target (%s) is enabled, disable to update parameters\n",
529 config_item_name(&nt->item));
530 goto out_unlock;
531 }
532
533 if (strnchr(buf, count, ':')) {
534 const char *end;
535 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
536 if (*end && *end != '\n') {
537 pr_err("invalid IPv6 address at: <%c>\n", *end);
538 goto out_unlock;
539 }
540 nt->np.ipv6 = true;
541 } else
542 goto out_unlock;
543 } else {
544 if (!nt->np.ipv6) {
545 nt->np.remote_ip.ip = in_aton(buf);
546 } else
547 goto out_unlock;
548 }
549
550 mutex_unlock(&dynamic_netconsole_mutex);
551 return strnlen(buf, count);
552out_unlock:
553 mutex_unlock(&dynamic_netconsole_mutex);
554 return -EINVAL;
555}
556
557static ssize_t remote_mac_store(struct config_item *item, const char *buf,
558 size_t count)
559{
560 struct netconsole_target *nt = to_target(item);
561 u8 remote_mac[ETH_ALEN];
562
563 mutex_lock(&dynamic_netconsole_mutex);
564 if (nt->enabled) {
565 pr_err("target (%s) is enabled, disable to update parameters\n",
566 config_item_name(&nt->item));
567 goto out_unlock;
568 }
569
570 if (!mac_pton(buf, remote_mac))
571 goto out_unlock;
572 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
573 goto out_unlock;
574 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
575
576 mutex_unlock(&dynamic_netconsole_mutex);
577 return strnlen(buf, count);
578out_unlock:
579 mutex_unlock(&dynamic_netconsole_mutex);
580 return -EINVAL;
581}
582
583CONFIGFS_ATTR(, enabled);
584CONFIGFS_ATTR(, extended);
585CONFIGFS_ATTR(, dev_name);
586CONFIGFS_ATTR(, local_port);
587CONFIGFS_ATTR(, remote_port);
588CONFIGFS_ATTR(, local_ip);
589CONFIGFS_ATTR(, remote_ip);
590CONFIGFS_ATTR_RO(, local_mac);
591CONFIGFS_ATTR(, remote_mac);
592
593static struct configfs_attribute *netconsole_target_attrs[] = {
594 &attr_enabled,
595 &attr_extended,
596 &attr_dev_name,
597 &attr_local_port,
598 &attr_remote_port,
599 &attr_local_ip,
600 &attr_remote_ip,
601 &attr_local_mac,
602 &attr_remote_mac,
603 NULL,
604};
605
606/*
607 * Item operations and type for netconsole_target.
608 */
609
610static void netconsole_target_release(struct config_item *item)
611{
612 kfree(to_target(item));
613}
614
615static struct configfs_item_operations netconsole_target_item_ops = {
616 .release = netconsole_target_release,
617};
618
619static const struct config_item_type netconsole_target_type = {
620 .ct_attrs = netconsole_target_attrs,
621 .ct_item_ops = &netconsole_target_item_ops,
622 .ct_owner = THIS_MODULE,
623};
624
625/*
626 * Group operations and type for netconsole_subsys.
627 */
628
629static struct config_item *make_netconsole_target(struct config_group *group,
630 const char *name)
631{
632 unsigned long flags;
633 struct netconsole_target *nt;
634
635 /*
636 * Allocate and initialize with defaults.
637 * Target is disabled at creation (!enabled).
638 */
639 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
640 if (!nt)
641 return ERR_PTR(-ENOMEM);
642
643 nt->np.name = "netconsole";
644 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
645 nt->np.local_port = 6665;
646 nt->np.remote_port = 6666;
647 eth_broadcast_addr(nt->np.remote_mac);
648
649 /* Initialize the config_item member */
650 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
651
652 /* Adding, but it is disabled */
653 spin_lock_irqsave(&target_list_lock, flags);
654 list_add(&nt->list, &target_list);
655 spin_unlock_irqrestore(&target_list_lock, flags);
656
657 return &nt->item;
658}
659
660static void drop_netconsole_target(struct config_group *group,
661 struct config_item *item)
662{
663 unsigned long flags;
664 struct netconsole_target *nt = to_target(item);
665
666 spin_lock_irqsave(&target_list_lock, flags);
667 list_del(&nt->list);
668 spin_unlock_irqrestore(&target_list_lock, flags);
669
670 /*
671 * The target may have never been enabled, or was manually disabled
672 * before being removed so netpoll may have already been cleaned up.
673 */
674 if (nt->enabled)
675 netpoll_cleanup(&nt->np);
676
677 config_item_put(&nt->item);
678}
679
680static struct configfs_group_operations netconsole_subsys_group_ops = {
681 .make_item = make_netconsole_target,
682 .drop_item = drop_netconsole_target,
683};
684
685static const struct config_item_type netconsole_subsys_type = {
686 .ct_group_ops = &netconsole_subsys_group_ops,
687 .ct_owner = THIS_MODULE,
688};
689
690/* The netconsole configfs subsystem */
691static struct configfs_subsystem netconsole_subsys = {
692 .su_group = {
693 .cg_item = {
694 .ci_namebuf = "netconsole",
695 .ci_type = &netconsole_subsys_type,
696 },
697 },
698};
699
700#endif /* CONFIG_NETCONSOLE_DYNAMIC */
701
702/* Handle network interface device notifications */
703static int netconsole_netdev_event(struct notifier_block *this,
704 unsigned long event, void *ptr)
705{
706 unsigned long flags;
707 struct netconsole_target *nt;
708 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
709 bool stopped = false;
710
711 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
712 event == NETDEV_RELEASE || event == NETDEV_JOIN))
713 goto done;
714
715 spin_lock_irqsave(&target_list_lock, flags);
716restart:
717 list_for_each_entry(nt, &target_list, list) {
718 netconsole_target_get(nt);
719 if (nt->np.dev == dev) {
720 switch (event) {
721 case NETDEV_CHANGENAME:
722 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
723 break;
724 case NETDEV_RELEASE:
725 case NETDEV_JOIN:
726 case NETDEV_UNREGISTER:
727 /* rtnl_lock already held
728 * we might sleep in __netpoll_cleanup()
729 */
730 spin_unlock_irqrestore(&target_list_lock, flags);
731
732 __netpoll_cleanup(&nt->np);
733
734 spin_lock_irqsave(&target_list_lock, flags);
735 dev_put(nt->np.dev);
736 nt->np.dev = NULL;
737 nt->enabled = false;
738 stopped = true;
739 netconsole_target_put(nt);
740 goto restart;
741 }
742 }
743 netconsole_target_put(nt);
744 }
745 spin_unlock_irqrestore(&target_list_lock, flags);
746 if (stopped) {
747 const char *msg = "had an event";
748 switch (event) {
749 case NETDEV_UNREGISTER:
750 msg = "unregistered";
751 break;
752 case NETDEV_RELEASE:
753 msg = "released slaves";
754 break;
755 case NETDEV_JOIN:
756 msg = "is joining a master device";
757 break;
758 }
759 pr_info("network logging stopped on interface %s as it %s\n",
760 dev->name, msg);
761 }
762
763done:
764 return NOTIFY_DONE;
765}
766
767static struct notifier_block netconsole_netdev_notifier = {
768 .notifier_call = netconsole_netdev_event,
769};
770
771/**
772 * send_ext_msg_udp - send extended log message to target
773 * @nt: target to send message to
774 * @msg: extended log message to send
775 * @msg_len: length of message
776 *
777 * Transfer extended log @msg to @nt. If @msg is longer than
778 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
779 * ncfrag header field added to identify them.
780 */
781static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
782 int msg_len)
783{
784 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
785 const char *header, *body;
786 int offset = 0;
787 int header_len, body_len;
788
789 if (msg_len <= MAX_PRINT_CHUNK) {
790 netpoll_send_udp(&nt->np, msg, msg_len);
791 return;
792 }
793
794 /* need to insert extra header fields, detect header and body */
795 header = msg;
796 body = memchr(msg, ';', msg_len);
797 if (WARN_ON_ONCE(!body))
798 return;
799
800 header_len = body - header;
801 body_len = msg_len - header_len - 1;
802 body++;
803
804 /*
805 * Transfer multiple chunks with the following extra header.
806 * "ncfrag=<byte-offset>/<total-bytes>"
807 */
808 memcpy(buf, header, header_len);
809
810 while (offset < body_len) {
811 int this_header = header_len;
812 int this_chunk;
813
814 this_header += scnprintf(buf + this_header,
815 sizeof(buf) - this_header,
816 ",ncfrag=%d/%d;", offset, body_len);
817
818 this_chunk = min(body_len - offset,
819 MAX_PRINT_CHUNK - this_header);
820 if (WARN_ON_ONCE(this_chunk <= 0))
821 return;
822
823 memcpy(buf + this_header, body + offset, this_chunk);
824
825 netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
826
827 offset += this_chunk;
828 }
829}
830
831static void write_ext_msg(struct console *con, const char *msg,
832 unsigned int len)
833{
834 struct netconsole_target *nt;
835 unsigned long flags;
836
837 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
838 return;
839
840 spin_lock_irqsave(&target_list_lock, flags);
841 list_for_each_entry(nt, &target_list, list)
842 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
843 send_ext_msg_udp(nt, msg, len);
844 spin_unlock_irqrestore(&target_list_lock, flags);
845}
846
847static void write_msg(struct console *con, const char *msg, unsigned int len)
848{
849 int frag, left;
850 unsigned long flags;
851 struct netconsole_target *nt;
852 const char *tmp;
853
854 if (oops_only && !oops_in_progress)
855 return;
856 /* Avoid taking lock and disabling interrupts unnecessarily */
857 if (list_empty(&target_list))
858 return;
859
860 spin_lock_irqsave(&target_list_lock, flags);
861 list_for_each_entry(nt, &target_list, list) {
862 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
863 /*
864 * We nest this inside the for-each-target loop above
865 * so that we're able to get as much logging out to
866 * at least one target if we die inside here, instead
867 * of unnecessarily keeping all targets in lock-step.
868 */
869 tmp = msg;
870 for (left = len; left;) {
871 frag = min(left, MAX_PRINT_CHUNK);
872 netpoll_send_udp(&nt->np, tmp, frag);
873 tmp += frag;
874 left -= frag;
875 }
876 }
877 }
878 spin_unlock_irqrestore(&target_list_lock, flags);
879}
880
881static struct console netconsole_ext = {
882 .name = "netcon_ext",
883 .flags = CON_EXTENDED, /* starts disabled, registered on first use */
884 .write = write_ext_msg,
885};
886
887static struct console netconsole = {
888 .name = "netcon",
889 .flags = CON_ENABLED,
890 .write = write_msg,
891};
892
893static int __init init_netconsole(void)
894{
895 int err;
896 struct netconsole_target *nt, *tmp;
897 unsigned long flags;
898 char *target_config;
899 char *input = config;
900
901 if (strnlen(input, MAX_PARAM_LENGTH)) {
902 while ((target_config = strsep(&input, ";"))) {
903 nt = alloc_param_target(target_config);
904 if (IS_ERR(nt)) {
905 err = PTR_ERR(nt);
906 goto fail;
907 }
908 /* Dump existing printks when we register */
909 if (nt->extended)
910 netconsole_ext.flags |= CON_PRINTBUFFER |
911 CON_ENABLED;
912 else
913 netconsole.flags |= CON_PRINTBUFFER;
914
915 spin_lock_irqsave(&target_list_lock, flags);
916 list_add(&nt->list, &target_list);
917 spin_unlock_irqrestore(&target_list_lock, flags);
918 }
919 }
920
921 err = register_netdevice_notifier(&netconsole_netdev_notifier);
922 if (err)
923 goto fail;
924
925 err = dynamic_netconsole_init();
926 if (err)
927 goto undonotifier;
928
929 if (netconsole_ext.flags & CON_ENABLED)
930 register_console(&netconsole_ext);
931 register_console(&netconsole);
932 pr_info("network logging started\n");
933
934 return err;
935
936undonotifier:
937 unregister_netdevice_notifier(&netconsole_netdev_notifier);
938
939fail:
940 pr_err("cleaning up\n");
941
942 /*
943 * Remove all targets and destroy them (only targets created
944 * from the boot/module option exist here). Skipping the list
945 * lock is safe here, and netpoll_cleanup() will sleep.
946 */
947 list_for_each_entry_safe(nt, tmp, &target_list, list) {
948 list_del(&nt->list);
949 free_param_target(nt);
950 }
951
952 return err;
953}
954
955static void __exit cleanup_netconsole(void)
956{
957 struct netconsole_target *nt, *tmp;
958
959 unregister_console(&netconsole_ext);
960 unregister_console(&netconsole);
961 dynamic_netconsole_exit();
962 unregister_netdevice_notifier(&netconsole_netdev_notifier);
963
964 /*
965 * Targets created via configfs pin references on our module
966 * and would first be rmdir(2)'ed from userspace. We reach
967 * here only when they are already destroyed, and only those
968 * created from the boot/module option are left, so remove and
969 * destroy them. Skipping the list lock is safe here, and
970 * netpoll_cleanup() will sleep.
971 */
972 list_for_each_entry_safe(nt, tmp, &target_list, list) {
973 list_del(&nt->list);
974 free_param_target(nt);
975 }
976}
977
978/*
979 * Use late_initcall to ensure netconsole is
980 * initialized after network device driver if built-in.
981 *
982 * late_initcall() and module_init() are identical if built as module.
983 */
984late_initcall(init_netconsole);
985module_exit(cleanup_netconsole);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * linux/drivers/net/netconsole.c
4 *
5 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
6 *
7 * This file contains the implementation of an IRQ-safe, crash-safe
8 * kernel console implementation that outputs kernel messages to the
9 * network.
10 *
11 * Modification history:
12 *
13 * 2001-09-17 started by Ingo Molnar.
14 * 2003-08-11 2.6 port by Matt Mackall
15 * simplified options
16 * generic card hooks
17 * works non-modular
18 * 2003-09-07 rewritten with netpoll api
19 */
20
21/****************************************************************
22 *
23 ****************************************************************/
24
25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/mm.h>
28#include <linux/init.h>
29#include <linux/module.h>
30#include <linux/slab.h>
31#include <linux/console.h>
32#include <linux/moduleparam.h>
33#include <linux/kernel.h>
34#include <linux/string.h>
35#include <linux/netpoll.h>
36#include <linux/inet.h>
37#include <linux/configfs.h>
38#include <linux/etherdevice.h>
39
40MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
41MODULE_DESCRIPTION("Console driver for network interfaces");
42MODULE_LICENSE("GPL");
43
44#define MAX_PARAM_LENGTH 256
45#define MAX_PRINT_CHUNK 1000
46
47static char config[MAX_PARAM_LENGTH];
48module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
49MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
50
51static bool oops_only = false;
52module_param(oops_only, bool, 0600);
53MODULE_PARM_DESC(oops_only, "Only log oops messages");
54
55#ifndef MODULE
56static int __init option_setup(char *opt)
57{
58 strlcpy(config, opt, MAX_PARAM_LENGTH);
59 return 1;
60}
61__setup("netconsole=", option_setup);
62#endif /* MODULE */
63
64/* Linked list of all configured targets */
65static LIST_HEAD(target_list);
66
67/* This needs to be a spinlock because write_msg() cannot sleep */
68static DEFINE_SPINLOCK(target_list_lock);
69
70/*
71 * Console driver for extended netconsoles. Registered on the first use to
72 * avoid unnecessarily enabling ext message formatting.
73 */
74static struct console netconsole_ext;
75
76/**
77 * struct netconsole_target - Represents a configured netconsole target.
78 * @list: Links this target into the target_list.
79 * @item: Links us into the configfs subsystem hierarchy.
80 * @enabled: On / off knob to enable / disable target.
81 * Visible from userspace (read-write).
82 * We maintain a strict 1:1 correspondence between this and
83 * whether the corresponding netpoll is active or inactive.
84 * Also, other parameters of a target may be modified at
85 * runtime only when it is disabled (enabled == 0).
86 * @extended: Denotes whether console is extended or not.
87 * @np: The netpoll structure for this target.
88 * Contains the other userspace visible parameters:
89 * dev_name (read-write)
90 * local_port (read-write)
91 * remote_port (read-write)
92 * local_ip (read-write)
93 * remote_ip (read-write)
94 * local_mac (read-only)
95 * remote_mac (read-write)
96 */
97struct netconsole_target {
98 struct list_head list;
99#ifdef CONFIG_NETCONSOLE_DYNAMIC
100 struct config_item item;
101#endif
102 bool enabled;
103 bool extended;
104 struct netpoll np;
105};
106
107#ifdef CONFIG_NETCONSOLE_DYNAMIC
108
109static struct configfs_subsystem netconsole_subsys;
110static DEFINE_MUTEX(dynamic_netconsole_mutex);
111
112static int __init dynamic_netconsole_init(void)
113{
114 config_group_init(&netconsole_subsys.su_group);
115 mutex_init(&netconsole_subsys.su_mutex);
116 return configfs_register_subsystem(&netconsole_subsys);
117}
118
119static void __exit dynamic_netconsole_exit(void)
120{
121 configfs_unregister_subsystem(&netconsole_subsys);
122}
123
124/*
125 * Targets that were created by parsing the boot/module option string
126 * do not exist in the configfs hierarchy (and have NULL names) and will
127 * never go away, so make these a no-op for them.
128 */
129static void netconsole_target_get(struct netconsole_target *nt)
130{
131 if (config_item_name(&nt->item))
132 config_item_get(&nt->item);
133}
134
135static void netconsole_target_put(struct netconsole_target *nt)
136{
137 if (config_item_name(&nt->item))
138 config_item_put(&nt->item);
139}
140
141#else /* !CONFIG_NETCONSOLE_DYNAMIC */
142
143static int __init dynamic_netconsole_init(void)
144{
145 return 0;
146}
147
148static void __exit dynamic_netconsole_exit(void)
149{
150}
151
152/*
153 * No danger of targets going away from under us when dynamic
154 * reconfigurability is off.
155 */
156static void netconsole_target_get(struct netconsole_target *nt)
157{
158}
159
160static void netconsole_target_put(struct netconsole_target *nt)
161{
162}
163
164#endif /* CONFIG_NETCONSOLE_DYNAMIC */
165
166/* Allocate new target (from boot/module param) and setup netpoll for it */
167static struct netconsole_target *alloc_param_target(char *target_config)
168{
169 int err = -ENOMEM;
170 struct netconsole_target *nt;
171
172 /*
173 * Allocate and initialize with defaults.
174 * Note that these targets get their config_item fields zeroed-out.
175 */
176 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
177 if (!nt)
178 goto fail;
179
180 nt->np.name = "netconsole";
181 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
182 nt->np.local_port = 6665;
183 nt->np.remote_port = 6666;
184 eth_broadcast_addr(nt->np.remote_mac);
185
186 if (*target_config == '+') {
187 nt->extended = true;
188 target_config++;
189 }
190
191 /* Parse parameters and setup netpoll */
192 err = netpoll_parse_options(&nt->np, target_config);
193 if (err)
194 goto fail;
195
196 err = netpoll_setup(&nt->np);
197 if (err)
198 goto fail;
199
200 nt->enabled = true;
201
202 return nt;
203
204fail:
205 kfree(nt);
206 return ERR_PTR(err);
207}
208
209/* Cleanup netpoll for given target (from boot/module param) and free it */
210static void free_param_target(struct netconsole_target *nt)
211{
212 netpoll_cleanup(&nt->np);
213 kfree(nt);
214}
215
216#ifdef CONFIG_NETCONSOLE_DYNAMIC
217
218/*
219 * Our subsystem hierarchy is:
220 *
221 * /sys/kernel/config/netconsole/
222 * |
223 * <target>/
224 * | enabled
225 * | dev_name
226 * | local_port
227 * | remote_port
228 * | local_ip
229 * | remote_ip
230 * | local_mac
231 * | remote_mac
232 * |
233 * <target>/...
234 */
235
236static struct netconsole_target *to_target(struct config_item *item)
237{
238 return item ?
239 container_of(item, struct netconsole_target, item) :
240 NULL;
241}
242
243/*
244 * Attribute operations for netconsole_target.
245 */
246
247static ssize_t enabled_show(struct config_item *item, char *buf)
248{
249 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->enabled);
250}
251
252static ssize_t extended_show(struct config_item *item, char *buf)
253{
254 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->extended);
255}
256
257static ssize_t dev_name_show(struct config_item *item, char *buf)
258{
259 return snprintf(buf, PAGE_SIZE, "%s\n", to_target(item)->np.dev_name);
260}
261
262static ssize_t local_port_show(struct config_item *item, char *buf)
263{
264 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.local_port);
265}
266
267static ssize_t remote_port_show(struct config_item *item, char *buf)
268{
269 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.remote_port);
270}
271
272static ssize_t local_ip_show(struct config_item *item, char *buf)
273{
274 struct netconsole_target *nt = to_target(item);
275
276 if (nt->np.ipv6)
277 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
278 else
279 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
280}
281
282static ssize_t remote_ip_show(struct config_item *item, char *buf)
283{
284 struct netconsole_target *nt = to_target(item);
285
286 if (nt->np.ipv6)
287 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
288 else
289 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
290}
291
292static ssize_t local_mac_show(struct config_item *item, char *buf)
293{
294 struct net_device *dev = to_target(item)->np.dev;
295 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
296
297 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
298}
299
300static ssize_t remote_mac_show(struct config_item *item, char *buf)
301{
302 return snprintf(buf, PAGE_SIZE, "%pM\n", to_target(item)->np.remote_mac);
303}
304
305/*
306 * This one is special -- targets created through the configfs interface
307 * are not enabled (and the corresponding netpoll activated) by default.
308 * The user is expected to set the desired parameters first (which
309 * would enable him to dynamically add new netpoll targets for new
310 * network interfaces as and when they come up).
311 */
312static ssize_t enabled_store(struct config_item *item,
313 const char *buf, size_t count)
314{
315 struct netconsole_target *nt = to_target(item);
316 unsigned long flags;
317 int enabled;
318 int err;
319
320 mutex_lock(&dynamic_netconsole_mutex);
321 err = kstrtoint(buf, 10, &enabled);
322 if (err < 0)
323 goto out_unlock;
324
325 err = -EINVAL;
326 if (enabled < 0 || enabled > 1)
327 goto out_unlock;
328 if ((bool)enabled == nt->enabled) {
329 pr_info("network logging has already %s\n",
330 nt->enabled ? "started" : "stopped");
331 goto out_unlock;
332 }
333
334 if (enabled) { /* true */
335 if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
336 netconsole_ext.flags |= CON_ENABLED;
337 register_console(&netconsole_ext);
338 }
339
340 /*
341 * Skip netpoll_parse_options() -- all the attributes are
342 * already configured via configfs. Just print them out.
343 */
344 netpoll_print_options(&nt->np);
345
346 err = netpoll_setup(&nt->np);
347 if (err)
348 goto out_unlock;
349
350 pr_info("network logging started\n");
351 } else { /* false */
352 /* We need to disable the netconsole before cleaning it up
353 * otherwise we might end up in write_msg() with
354 * nt->np.dev == NULL and nt->enabled == true
355 */
356 spin_lock_irqsave(&target_list_lock, flags);
357 nt->enabled = false;
358 spin_unlock_irqrestore(&target_list_lock, flags);
359 netpoll_cleanup(&nt->np);
360 }
361
362 nt->enabled = enabled;
363
364 mutex_unlock(&dynamic_netconsole_mutex);
365 return strnlen(buf, count);
366out_unlock:
367 mutex_unlock(&dynamic_netconsole_mutex);
368 return err;
369}
370
371static ssize_t extended_store(struct config_item *item, const char *buf,
372 size_t count)
373{
374 struct netconsole_target *nt = to_target(item);
375 int extended;
376 int err;
377
378 mutex_lock(&dynamic_netconsole_mutex);
379 if (nt->enabled) {
380 pr_err("target (%s) is enabled, disable to update parameters\n",
381 config_item_name(&nt->item));
382 err = -EINVAL;
383 goto out_unlock;
384 }
385
386 err = kstrtoint(buf, 10, &extended);
387 if (err < 0)
388 goto out_unlock;
389 if (extended < 0 || extended > 1) {
390 err = -EINVAL;
391 goto out_unlock;
392 }
393
394 nt->extended = extended;
395
396 mutex_unlock(&dynamic_netconsole_mutex);
397 return strnlen(buf, count);
398out_unlock:
399 mutex_unlock(&dynamic_netconsole_mutex);
400 return err;
401}
402
403static ssize_t dev_name_store(struct config_item *item, const char *buf,
404 size_t count)
405{
406 struct netconsole_target *nt = to_target(item);
407 size_t len;
408
409 mutex_lock(&dynamic_netconsole_mutex);
410 if (nt->enabled) {
411 pr_err("target (%s) is enabled, disable to update parameters\n",
412 config_item_name(&nt->item));
413 mutex_unlock(&dynamic_netconsole_mutex);
414 return -EINVAL;
415 }
416
417 strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
418
419 /* Get rid of possible trailing newline from echo(1) */
420 len = strnlen(nt->np.dev_name, IFNAMSIZ);
421 if (nt->np.dev_name[len - 1] == '\n')
422 nt->np.dev_name[len - 1] = '\0';
423
424 mutex_unlock(&dynamic_netconsole_mutex);
425 return strnlen(buf, count);
426}
427
428static ssize_t local_port_store(struct config_item *item, const char *buf,
429 size_t count)
430{
431 struct netconsole_target *nt = to_target(item);
432 int rv = -EINVAL;
433
434 mutex_lock(&dynamic_netconsole_mutex);
435 if (nt->enabled) {
436 pr_err("target (%s) is enabled, disable to update parameters\n",
437 config_item_name(&nt->item));
438 goto out_unlock;
439 }
440
441 rv = kstrtou16(buf, 10, &nt->np.local_port);
442 if (rv < 0)
443 goto out_unlock;
444 mutex_unlock(&dynamic_netconsole_mutex);
445 return strnlen(buf, count);
446out_unlock:
447 mutex_unlock(&dynamic_netconsole_mutex);
448 return rv;
449}
450
451static ssize_t remote_port_store(struct config_item *item,
452 const char *buf, size_t count)
453{
454 struct netconsole_target *nt = to_target(item);
455 int rv = -EINVAL;
456
457 mutex_lock(&dynamic_netconsole_mutex);
458 if (nt->enabled) {
459 pr_err("target (%s) is enabled, disable to update parameters\n",
460 config_item_name(&nt->item));
461 goto out_unlock;
462 }
463
464 rv = kstrtou16(buf, 10, &nt->np.remote_port);
465 if (rv < 0)
466 goto out_unlock;
467 mutex_unlock(&dynamic_netconsole_mutex);
468 return strnlen(buf, count);
469out_unlock:
470 mutex_unlock(&dynamic_netconsole_mutex);
471 return rv;
472}
473
474static ssize_t local_ip_store(struct config_item *item, const char *buf,
475 size_t count)
476{
477 struct netconsole_target *nt = to_target(item);
478
479 mutex_lock(&dynamic_netconsole_mutex);
480 if (nt->enabled) {
481 pr_err("target (%s) is enabled, disable to update parameters\n",
482 config_item_name(&nt->item));
483 goto out_unlock;
484 }
485
486 if (strnchr(buf, count, ':')) {
487 const char *end;
488 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
489 if (*end && *end != '\n') {
490 pr_err("invalid IPv6 address at: <%c>\n", *end);
491 goto out_unlock;
492 }
493 nt->np.ipv6 = true;
494 } else
495 goto out_unlock;
496 } else {
497 if (!nt->np.ipv6) {
498 nt->np.local_ip.ip = in_aton(buf);
499 } else
500 goto out_unlock;
501 }
502
503 mutex_unlock(&dynamic_netconsole_mutex);
504 return strnlen(buf, count);
505out_unlock:
506 mutex_unlock(&dynamic_netconsole_mutex);
507 return -EINVAL;
508}
509
510static ssize_t remote_ip_store(struct config_item *item, const char *buf,
511 size_t count)
512{
513 struct netconsole_target *nt = to_target(item);
514
515 mutex_lock(&dynamic_netconsole_mutex);
516 if (nt->enabled) {
517 pr_err("target (%s) is enabled, disable to update parameters\n",
518 config_item_name(&nt->item));
519 goto out_unlock;
520 }
521
522 if (strnchr(buf, count, ':')) {
523 const char *end;
524 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
525 if (*end && *end != '\n') {
526 pr_err("invalid IPv6 address at: <%c>\n", *end);
527 goto out_unlock;
528 }
529 nt->np.ipv6 = true;
530 } else
531 goto out_unlock;
532 } else {
533 if (!nt->np.ipv6) {
534 nt->np.remote_ip.ip = in_aton(buf);
535 } else
536 goto out_unlock;
537 }
538
539 mutex_unlock(&dynamic_netconsole_mutex);
540 return strnlen(buf, count);
541out_unlock:
542 mutex_unlock(&dynamic_netconsole_mutex);
543 return -EINVAL;
544}
545
546static ssize_t remote_mac_store(struct config_item *item, const char *buf,
547 size_t count)
548{
549 struct netconsole_target *nt = to_target(item);
550 u8 remote_mac[ETH_ALEN];
551
552 mutex_lock(&dynamic_netconsole_mutex);
553 if (nt->enabled) {
554 pr_err("target (%s) is enabled, disable to update parameters\n",
555 config_item_name(&nt->item));
556 goto out_unlock;
557 }
558
559 if (!mac_pton(buf, remote_mac))
560 goto out_unlock;
561 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
562 goto out_unlock;
563 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
564
565 mutex_unlock(&dynamic_netconsole_mutex);
566 return strnlen(buf, count);
567out_unlock:
568 mutex_unlock(&dynamic_netconsole_mutex);
569 return -EINVAL;
570}
571
572CONFIGFS_ATTR(, enabled);
573CONFIGFS_ATTR(, extended);
574CONFIGFS_ATTR(, dev_name);
575CONFIGFS_ATTR(, local_port);
576CONFIGFS_ATTR(, remote_port);
577CONFIGFS_ATTR(, local_ip);
578CONFIGFS_ATTR(, remote_ip);
579CONFIGFS_ATTR_RO(, local_mac);
580CONFIGFS_ATTR(, remote_mac);
581
582static struct configfs_attribute *netconsole_target_attrs[] = {
583 &attr_enabled,
584 &attr_extended,
585 &attr_dev_name,
586 &attr_local_port,
587 &attr_remote_port,
588 &attr_local_ip,
589 &attr_remote_ip,
590 &attr_local_mac,
591 &attr_remote_mac,
592 NULL,
593};
594
595/*
596 * Item operations and type for netconsole_target.
597 */
598
599static void netconsole_target_release(struct config_item *item)
600{
601 kfree(to_target(item));
602}
603
604static struct configfs_item_operations netconsole_target_item_ops = {
605 .release = netconsole_target_release,
606};
607
608static const struct config_item_type netconsole_target_type = {
609 .ct_attrs = netconsole_target_attrs,
610 .ct_item_ops = &netconsole_target_item_ops,
611 .ct_owner = THIS_MODULE,
612};
613
614/*
615 * Group operations and type for netconsole_subsys.
616 */
617
618static struct config_item *make_netconsole_target(struct config_group *group,
619 const char *name)
620{
621 unsigned long flags;
622 struct netconsole_target *nt;
623
624 /*
625 * Allocate and initialize with defaults.
626 * Target is disabled at creation (!enabled).
627 */
628 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
629 if (!nt)
630 return ERR_PTR(-ENOMEM);
631
632 nt->np.name = "netconsole";
633 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
634 nt->np.local_port = 6665;
635 nt->np.remote_port = 6666;
636 eth_broadcast_addr(nt->np.remote_mac);
637
638 /* Initialize the config_item member */
639 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
640
641 /* Adding, but it is disabled */
642 spin_lock_irqsave(&target_list_lock, flags);
643 list_add(&nt->list, &target_list);
644 spin_unlock_irqrestore(&target_list_lock, flags);
645
646 return &nt->item;
647}
648
649static void drop_netconsole_target(struct config_group *group,
650 struct config_item *item)
651{
652 unsigned long flags;
653 struct netconsole_target *nt = to_target(item);
654
655 spin_lock_irqsave(&target_list_lock, flags);
656 list_del(&nt->list);
657 spin_unlock_irqrestore(&target_list_lock, flags);
658
659 /*
660 * The target may have never been enabled, or was manually disabled
661 * before being removed so netpoll may have already been cleaned up.
662 */
663 if (nt->enabled)
664 netpoll_cleanup(&nt->np);
665
666 config_item_put(&nt->item);
667}
668
669static struct configfs_group_operations netconsole_subsys_group_ops = {
670 .make_item = make_netconsole_target,
671 .drop_item = drop_netconsole_target,
672};
673
674static const struct config_item_type netconsole_subsys_type = {
675 .ct_group_ops = &netconsole_subsys_group_ops,
676 .ct_owner = THIS_MODULE,
677};
678
679/* The netconsole configfs subsystem */
680static struct configfs_subsystem netconsole_subsys = {
681 .su_group = {
682 .cg_item = {
683 .ci_namebuf = "netconsole",
684 .ci_type = &netconsole_subsys_type,
685 },
686 },
687};
688
689#endif /* CONFIG_NETCONSOLE_DYNAMIC */
690
691/* Handle network interface device notifications */
692static int netconsole_netdev_event(struct notifier_block *this,
693 unsigned long event, void *ptr)
694{
695 unsigned long flags;
696 struct netconsole_target *nt;
697 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
698 bool stopped = false;
699
700 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
701 event == NETDEV_RELEASE || event == NETDEV_JOIN))
702 goto done;
703
704 spin_lock_irqsave(&target_list_lock, flags);
705restart:
706 list_for_each_entry(nt, &target_list, list) {
707 netconsole_target_get(nt);
708 if (nt->np.dev == dev) {
709 switch (event) {
710 case NETDEV_CHANGENAME:
711 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
712 break;
713 case NETDEV_RELEASE:
714 case NETDEV_JOIN:
715 case NETDEV_UNREGISTER:
716 /* rtnl_lock already held
717 * we might sleep in __netpoll_cleanup()
718 */
719 spin_unlock_irqrestore(&target_list_lock, flags);
720
721 __netpoll_cleanup(&nt->np);
722
723 spin_lock_irqsave(&target_list_lock, flags);
724 dev_put(nt->np.dev);
725 nt->np.dev = NULL;
726 nt->enabled = false;
727 stopped = true;
728 netconsole_target_put(nt);
729 goto restart;
730 }
731 }
732 netconsole_target_put(nt);
733 }
734 spin_unlock_irqrestore(&target_list_lock, flags);
735 if (stopped) {
736 const char *msg = "had an event";
737 switch (event) {
738 case NETDEV_UNREGISTER:
739 msg = "unregistered";
740 break;
741 case NETDEV_RELEASE:
742 msg = "released slaves";
743 break;
744 case NETDEV_JOIN:
745 msg = "is joining a master device";
746 break;
747 }
748 pr_info("network logging stopped on interface %s as it %s\n",
749 dev->name, msg);
750 }
751
752done:
753 return NOTIFY_DONE;
754}
755
756static struct notifier_block netconsole_netdev_notifier = {
757 .notifier_call = netconsole_netdev_event,
758};
759
760/**
761 * send_ext_msg_udp - send extended log message to target
762 * @nt: target to send message to
763 * @msg: extended log message to send
764 * @msg_len: length of message
765 *
766 * Transfer extended log @msg to @nt. If @msg is longer than
767 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
768 * ncfrag header field added to identify them.
769 */
770static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
771 int msg_len)
772{
773 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
774 const char *header, *body;
775 int offset = 0;
776 int header_len, body_len;
777
778 if (msg_len <= MAX_PRINT_CHUNK) {
779 netpoll_send_udp(&nt->np, msg, msg_len);
780 return;
781 }
782
783 /* need to insert extra header fields, detect header and body */
784 header = msg;
785 body = memchr(msg, ';', msg_len);
786 if (WARN_ON_ONCE(!body))
787 return;
788
789 header_len = body - header;
790 body_len = msg_len - header_len - 1;
791 body++;
792
793 /*
794 * Transfer multiple chunks with the following extra header.
795 * "ncfrag=<byte-offset>/<total-bytes>"
796 */
797 memcpy(buf, header, header_len);
798
799 while (offset < body_len) {
800 int this_header = header_len;
801 int this_chunk;
802
803 this_header += scnprintf(buf + this_header,
804 sizeof(buf) - this_header,
805 ",ncfrag=%d/%d;", offset, body_len);
806
807 this_chunk = min(body_len - offset,
808 MAX_PRINT_CHUNK - this_header);
809 if (WARN_ON_ONCE(this_chunk <= 0))
810 return;
811
812 memcpy(buf + this_header, body + offset, this_chunk);
813
814 netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
815
816 offset += this_chunk;
817 }
818}
819
820static void write_ext_msg(struct console *con, const char *msg,
821 unsigned int len)
822{
823 struct netconsole_target *nt;
824 unsigned long flags;
825
826 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
827 return;
828
829 spin_lock_irqsave(&target_list_lock, flags);
830 list_for_each_entry(nt, &target_list, list)
831 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
832 send_ext_msg_udp(nt, msg, len);
833 spin_unlock_irqrestore(&target_list_lock, flags);
834}
835
836static void write_msg(struct console *con, const char *msg, unsigned int len)
837{
838 int frag, left;
839 unsigned long flags;
840 struct netconsole_target *nt;
841 const char *tmp;
842
843 if (oops_only && !oops_in_progress)
844 return;
845 /* Avoid taking lock and disabling interrupts unnecessarily */
846 if (list_empty(&target_list))
847 return;
848
849 spin_lock_irqsave(&target_list_lock, flags);
850 list_for_each_entry(nt, &target_list, list) {
851 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
852 /*
853 * We nest this inside the for-each-target loop above
854 * so that we're able to get as much logging out to
855 * at least one target if we die inside here, instead
856 * of unnecessarily keeping all targets in lock-step.
857 */
858 tmp = msg;
859 for (left = len; left;) {
860 frag = min(left, MAX_PRINT_CHUNK);
861 netpoll_send_udp(&nt->np, tmp, frag);
862 tmp += frag;
863 left -= frag;
864 }
865 }
866 }
867 spin_unlock_irqrestore(&target_list_lock, flags);
868}
869
870static struct console netconsole_ext = {
871 .name = "netcon_ext",
872 .flags = CON_EXTENDED, /* starts disabled, registered on first use */
873 .write = write_ext_msg,
874};
875
876static struct console netconsole = {
877 .name = "netcon",
878 .flags = CON_ENABLED,
879 .write = write_msg,
880};
881
882static int __init init_netconsole(void)
883{
884 int err;
885 struct netconsole_target *nt, *tmp;
886 unsigned long flags;
887 char *target_config;
888 char *input = config;
889
890 if (strnlen(input, MAX_PARAM_LENGTH)) {
891 while ((target_config = strsep(&input, ";"))) {
892 nt = alloc_param_target(target_config);
893 if (IS_ERR(nt)) {
894 err = PTR_ERR(nt);
895 goto fail;
896 }
897 /* Dump existing printks when we register */
898 if (nt->extended)
899 netconsole_ext.flags |= CON_PRINTBUFFER |
900 CON_ENABLED;
901 else
902 netconsole.flags |= CON_PRINTBUFFER;
903
904 spin_lock_irqsave(&target_list_lock, flags);
905 list_add(&nt->list, &target_list);
906 spin_unlock_irqrestore(&target_list_lock, flags);
907 }
908 }
909
910 err = register_netdevice_notifier(&netconsole_netdev_notifier);
911 if (err)
912 goto fail;
913
914 err = dynamic_netconsole_init();
915 if (err)
916 goto undonotifier;
917
918 if (netconsole_ext.flags & CON_ENABLED)
919 register_console(&netconsole_ext);
920 register_console(&netconsole);
921 pr_info("network logging started\n");
922
923 return err;
924
925undonotifier:
926 unregister_netdevice_notifier(&netconsole_netdev_notifier);
927
928fail:
929 pr_err("cleaning up\n");
930
931 /*
932 * Remove all targets and destroy them (only targets created
933 * from the boot/module option exist here). Skipping the list
934 * lock is safe here, and netpoll_cleanup() will sleep.
935 */
936 list_for_each_entry_safe(nt, tmp, &target_list, list) {
937 list_del(&nt->list);
938 free_param_target(nt);
939 }
940
941 return err;
942}
943
944static void __exit cleanup_netconsole(void)
945{
946 struct netconsole_target *nt, *tmp;
947
948 unregister_console(&netconsole_ext);
949 unregister_console(&netconsole);
950 dynamic_netconsole_exit();
951 unregister_netdevice_notifier(&netconsole_netdev_notifier);
952
953 /*
954 * Targets created via configfs pin references on our module
955 * and would first be rmdir(2)'ed from userspace. We reach
956 * here only when they are already destroyed, and only those
957 * created from the boot/module option are left, so remove and
958 * destroy them. Skipping the list lock is safe here, and
959 * netpoll_cleanup() will sleep.
960 */
961 list_for_each_entry_safe(nt, tmp, &target_list, list) {
962 list_del(&nt->list);
963 free_param_target(nt);
964 }
965}
966
967/*
968 * Use late_initcall to ensure netconsole is
969 * initialized after network device driver if built-in.
970 *
971 * late_initcall() and module_init() are identical if built as module.
972 */
973late_initcall(init_netconsole);
974module_exit(cleanup_netconsole);