Loading...
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#include <linux/utsname.h>
40
41MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
42MODULE_DESCRIPTION("Console driver for network interfaces");
43MODULE_LICENSE("GPL");
44
45#define MAX_PARAM_LENGTH 256
46#define MAX_PRINT_CHUNK 1000
47
48static char config[MAX_PARAM_LENGTH];
49module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
50MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
51
52static bool oops_only = false;
53module_param(oops_only, bool, 0600);
54MODULE_PARM_DESC(oops_only, "Only log oops messages");
55
56#define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline"
57
58#ifndef MODULE
59static int __init option_setup(char *opt)
60{
61 strscpy(config, opt, MAX_PARAM_LENGTH);
62 return 1;
63}
64__setup("netconsole=", option_setup);
65#endif /* MODULE */
66
67/* Linked list of all configured targets */
68static LIST_HEAD(target_list);
69
70/* This needs to be a spinlock because write_msg() cannot sleep */
71static DEFINE_SPINLOCK(target_list_lock);
72
73/*
74 * Console driver for extended netconsoles. Registered on the first use to
75 * avoid unnecessarily enabling ext message formatting.
76 */
77static struct console netconsole_ext;
78
79/**
80 * struct netconsole_target - Represents a configured netconsole target.
81 * @list: Links this target into the target_list.
82 * @item: Links us into the configfs subsystem hierarchy.
83 * @enabled: On / off knob to enable / disable target.
84 * Visible from userspace (read-write).
85 * We maintain a strict 1:1 correspondence between this and
86 * whether the corresponding netpoll is active or inactive.
87 * Also, other parameters of a target may be modified at
88 * runtime only when it is disabled (enabled == 0).
89 * @extended: Denotes whether console is extended or not.
90 * @release: Denotes whether kernel release version should be prepended
91 * to the message. Depends on extended console.
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 */
102struct netconsole_target {
103 struct list_head list;
104#ifdef CONFIG_NETCONSOLE_DYNAMIC
105 struct config_item item;
106#endif
107 bool enabled;
108 bool extended;
109 bool release;
110 struct netpoll np;
111};
112
113#ifdef CONFIG_NETCONSOLE_DYNAMIC
114
115static struct configfs_subsystem netconsole_subsys;
116static DEFINE_MUTEX(dynamic_netconsole_mutex);
117
118static int __init dynamic_netconsole_init(void)
119{
120 config_group_init(&netconsole_subsys.su_group);
121 mutex_init(&netconsole_subsys.su_mutex);
122 return configfs_register_subsystem(&netconsole_subsys);
123}
124
125static void __exit dynamic_netconsole_exit(void)
126{
127 configfs_unregister_subsystem(&netconsole_subsys);
128}
129
130/*
131 * Targets that were created by parsing the boot/module option string
132 * do not exist in the configfs hierarchy (and have NULL names) and will
133 * never go away, so make these a no-op for them.
134 */
135static void netconsole_target_get(struct netconsole_target *nt)
136{
137 if (config_item_name(&nt->item))
138 config_item_get(&nt->item);
139}
140
141static void netconsole_target_put(struct netconsole_target *nt)
142{
143 if (config_item_name(&nt->item))
144 config_item_put(&nt->item);
145}
146
147#else /* !CONFIG_NETCONSOLE_DYNAMIC */
148
149static int __init dynamic_netconsole_init(void)
150{
151 return 0;
152}
153
154static void __exit dynamic_netconsole_exit(void)
155{
156}
157
158/*
159 * No danger of targets going away from under us when dynamic
160 * reconfigurability is off.
161 */
162static void netconsole_target_get(struct netconsole_target *nt)
163{
164}
165
166static void netconsole_target_put(struct netconsole_target *nt)
167{
168}
169
170static void populate_configfs_item(struct netconsole_target *nt,
171 int cmdline_count)
172{
173}
174#endif /* CONFIG_NETCONSOLE_DYNAMIC */
175
176/* Allocate and initialize with defaults.
177 * Note that these targets get their config_item fields zeroed-out.
178 */
179static struct netconsole_target *alloc_and_init(void)
180{
181 struct netconsole_target *nt;
182
183 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
184 if (!nt)
185 return nt;
186
187 if (IS_ENABLED(CONFIG_NETCONSOLE_EXTENDED_LOG))
188 nt->extended = true;
189 if (IS_ENABLED(CONFIG_NETCONSOLE_PREPEND_RELEASE))
190 nt->release = true;
191
192 nt->np.name = "netconsole";
193 strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
194 nt->np.local_port = 6665;
195 nt->np.remote_port = 6666;
196 eth_broadcast_addr(nt->np.remote_mac);
197
198 return nt;
199}
200
201#ifdef CONFIG_NETCONSOLE_DYNAMIC
202
203/*
204 * Our subsystem hierarchy is:
205 *
206 * /sys/kernel/config/netconsole/
207 * |
208 * <target>/
209 * | enabled
210 * | release
211 * | dev_name
212 * | local_port
213 * | remote_port
214 * | local_ip
215 * | remote_ip
216 * | local_mac
217 * | remote_mac
218 * |
219 * <target>/...
220 */
221
222static struct netconsole_target *to_target(struct config_item *item)
223{
224 return item ?
225 container_of(item, struct netconsole_target, item) :
226 NULL;
227}
228
229/*
230 * Attribute operations for netconsole_target.
231 */
232
233static ssize_t enabled_show(struct config_item *item, char *buf)
234{
235 return sysfs_emit(buf, "%d\n", to_target(item)->enabled);
236}
237
238static ssize_t extended_show(struct config_item *item, char *buf)
239{
240 return sysfs_emit(buf, "%d\n", to_target(item)->extended);
241}
242
243static ssize_t release_show(struct config_item *item, char *buf)
244{
245 return sysfs_emit(buf, "%d\n", to_target(item)->release);
246}
247
248static ssize_t dev_name_show(struct config_item *item, char *buf)
249{
250 return sysfs_emit(buf, "%s\n", to_target(item)->np.dev_name);
251}
252
253static ssize_t local_port_show(struct config_item *item, char *buf)
254{
255 return sysfs_emit(buf, "%d\n", to_target(item)->np.local_port);
256}
257
258static ssize_t remote_port_show(struct config_item *item, char *buf)
259{
260 return sysfs_emit(buf, "%d\n", to_target(item)->np.remote_port);
261}
262
263static ssize_t local_ip_show(struct config_item *item, char *buf)
264{
265 struct netconsole_target *nt = to_target(item);
266
267 if (nt->np.ipv6)
268 return sysfs_emit(buf, "%pI6c\n", &nt->np.local_ip.in6);
269 else
270 return sysfs_emit(buf, "%pI4\n", &nt->np.local_ip);
271}
272
273static ssize_t remote_ip_show(struct config_item *item, char *buf)
274{
275 struct netconsole_target *nt = to_target(item);
276
277 if (nt->np.ipv6)
278 return sysfs_emit(buf, "%pI6c\n", &nt->np.remote_ip.in6);
279 else
280 return sysfs_emit(buf, "%pI4\n", &nt->np.remote_ip);
281}
282
283static ssize_t local_mac_show(struct config_item *item, char *buf)
284{
285 struct net_device *dev = to_target(item)->np.dev;
286 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
287
288 return sysfs_emit(buf, "%pM\n", dev ? dev->dev_addr : bcast);
289}
290
291static ssize_t remote_mac_show(struct config_item *item, char *buf)
292{
293 return sysfs_emit(buf, "%pM\n", to_target(item)->np.remote_mac);
294}
295
296/*
297 * This one is special -- targets created through the configfs interface
298 * are not enabled (and the corresponding netpoll activated) by default.
299 * The user is expected to set the desired parameters first (which
300 * would enable him to dynamically add new netpoll targets for new
301 * network interfaces as and when they come up).
302 */
303static ssize_t enabled_store(struct config_item *item,
304 const char *buf, size_t count)
305{
306 struct netconsole_target *nt = to_target(item);
307 unsigned long flags;
308 bool enabled;
309 int err;
310
311 mutex_lock(&dynamic_netconsole_mutex);
312 err = kstrtobool(buf, &enabled);
313 if (err)
314 goto out_unlock;
315
316 err = -EINVAL;
317 if ((bool)enabled == nt->enabled) {
318 pr_info("network logging has already %s\n",
319 nt->enabled ? "started" : "stopped");
320 goto out_unlock;
321 }
322
323 if (enabled) { /* true */
324 if (nt->release && !nt->extended) {
325 pr_err("Not enabling netconsole. Release feature requires extended log message");
326 goto out_unlock;
327 }
328
329 if (nt->extended && !console_is_registered(&netconsole_ext))
330 register_console(&netconsole_ext);
331
332 /*
333 * Skip netpoll_parse_options() -- all the attributes are
334 * already configured via configfs. Just print them out.
335 */
336 netpoll_print_options(&nt->np);
337
338 err = netpoll_setup(&nt->np);
339 if (err)
340 goto out_unlock;
341
342 pr_info("network logging started\n");
343 } else { /* false */
344 /* We need to disable the netconsole before cleaning it up
345 * otherwise we might end up in write_msg() with
346 * nt->np.dev == NULL and nt->enabled == true
347 */
348 spin_lock_irqsave(&target_list_lock, flags);
349 nt->enabled = false;
350 spin_unlock_irqrestore(&target_list_lock, flags);
351 netpoll_cleanup(&nt->np);
352 }
353
354 nt->enabled = enabled;
355
356 mutex_unlock(&dynamic_netconsole_mutex);
357 return strnlen(buf, count);
358out_unlock:
359 mutex_unlock(&dynamic_netconsole_mutex);
360 return err;
361}
362
363static ssize_t release_store(struct config_item *item, const char *buf,
364 size_t count)
365{
366 struct netconsole_target *nt = to_target(item);
367 bool release;
368 int err;
369
370 mutex_lock(&dynamic_netconsole_mutex);
371 if (nt->enabled) {
372 pr_err("target (%s) is enabled, disable to update parameters\n",
373 config_item_name(&nt->item));
374 err = -EINVAL;
375 goto out_unlock;
376 }
377
378 err = kstrtobool(buf, &release);
379 if (err)
380 goto out_unlock;
381
382 nt->release = release;
383
384 mutex_unlock(&dynamic_netconsole_mutex);
385 return strnlen(buf, count);
386out_unlock:
387 mutex_unlock(&dynamic_netconsole_mutex);
388 return err;
389}
390
391static ssize_t extended_store(struct config_item *item, const char *buf,
392 size_t count)
393{
394 struct netconsole_target *nt = to_target(item);
395 bool extended;
396 int err;
397
398 mutex_lock(&dynamic_netconsole_mutex);
399 if (nt->enabled) {
400 pr_err("target (%s) is enabled, disable to update parameters\n",
401 config_item_name(&nt->item));
402 err = -EINVAL;
403 goto out_unlock;
404 }
405
406 err = kstrtobool(buf, &extended);
407 if (err)
408 goto out_unlock;
409
410 nt->extended = extended;
411
412 mutex_unlock(&dynamic_netconsole_mutex);
413 return strnlen(buf, count);
414out_unlock:
415 mutex_unlock(&dynamic_netconsole_mutex);
416 return err;
417}
418
419static ssize_t dev_name_store(struct config_item *item, const char *buf,
420 size_t count)
421{
422 struct netconsole_target *nt = to_target(item);
423 size_t len;
424
425 mutex_lock(&dynamic_netconsole_mutex);
426 if (nt->enabled) {
427 pr_err("target (%s) is enabled, disable to update parameters\n",
428 config_item_name(&nt->item));
429 mutex_unlock(&dynamic_netconsole_mutex);
430 return -EINVAL;
431 }
432
433 strscpy(nt->np.dev_name, buf, IFNAMSIZ);
434
435 /* Get rid of possible trailing newline from echo(1) */
436 len = strnlen(nt->np.dev_name, IFNAMSIZ);
437 if (nt->np.dev_name[len - 1] == '\n')
438 nt->np.dev_name[len - 1] = '\0';
439
440 mutex_unlock(&dynamic_netconsole_mutex);
441 return strnlen(buf, count);
442}
443
444static ssize_t local_port_store(struct config_item *item, const char *buf,
445 size_t count)
446{
447 struct netconsole_target *nt = to_target(item);
448 int rv = -EINVAL;
449
450 mutex_lock(&dynamic_netconsole_mutex);
451 if (nt->enabled) {
452 pr_err("target (%s) is enabled, disable to update parameters\n",
453 config_item_name(&nt->item));
454 goto out_unlock;
455 }
456
457 rv = kstrtou16(buf, 10, &nt->np.local_port);
458 if (rv < 0)
459 goto out_unlock;
460 mutex_unlock(&dynamic_netconsole_mutex);
461 return strnlen(buf, count);
462out_unlock:
463 mutex_unlock(&dynamic_netconsole_mutex);
464 return rv;
465}
466
467static ssize_t remote_port_store(struct config_item *item,
468 const char *buf, size_t count)
469{
470 struct netconsole_target *nt = to_target(item);
471 int rv = -EINVAL;
472
473 mutex_lock(&dynamic_netconsole_mutex);
474 if (nt->enabled) {
475 pr_err("target (%s) is enabled, disable to update parameters\n",
476 config_item_name(&nt->item));
477 goto out_unlock;
478 }
479
480 rv = kstrtou16(buf, 10, &nt->np.remote_port);
481 if (rv < 0)
482 goto out_unlock;
483 mutex_unlock(&dynamic_netconsole_mutex);
484 return strnlen(buf, count);
485out_unlock:
486 mutex_unlock(&dynamic_netconsole_mutex);
487 return rv;
488}
489
490static ssize_t local_ip_store(struct config_item *item, const char *buf,
491 size_t count)
492{
493 struct netconsole_target *nt = to_target(item);
494
495 mutex_lock(&dynamic_netconsole_mutex);
496 if (nt->enabled) {
497 pr_err("target (%s) is enabled, disable to update parameters\n",
498 config_item_name(&nt->item));
499 goto out_unlock;
500 }
501
502 if (strnchr(buf, count, ':')) {
503 const char *end;
504 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
505 if (*end && *end != '\n') {
506 pr_err("invalid IPv6 address at: <%c>\n", *end);
507 goto out_unlock;
508 }
509 nt->np.ipv6 = true;
510 } else
511 goto out_unlock;
512 } else {
513 if (!nt->np.ipv6) {
514 nt->np.local_ip.ip = in_aton(buf);
515 } else
516 goto out_unlock;
517 }
518
519 mutex_unlock(&dynamic_netconsole_mutex);
520 return strnlen(buf, count);
521out_unlock:
522 mutex_unlock(&dynamic_netconsole_mutex);
523 return -EINVAL;
524}
525
526static ssize_t remote_ip_store(struct config_item *item, const char *buf,
527 size_t count)
528{
529 struct netconsole_target *nt = to_target(item);
530
531 mutex_lock(&dynamic_netconsole_mutex);
532 if (nt->enabled) {
533 pr_err("target (%s) is enabled, disable to update parameters\n",
534 config_item_name(&nt->item));
535 goto out_unlock;
536 }
537
538 if (strnchr(buf, count, ':')) {
539 const char *end;
540 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
541 if (*end && *end != '\n') {
542 pr_err("invalid IPv6 address at: <%c>\n", *end);
543 goto out_unlock;
544 }
545 nt->np.ipv6 = true;
546 } else
547 goto out_unlock;
548 } else {
549 if (!nt->np.ipv6) {
550 nt->np.remote_ip.ip = in_aton(buf);
551 } else
552 goto out_unlock;
553 }
554
555 mutex_unlock(&dynamic_netconsole_mutex);
556 return strnlen(buf, count);
557out_unlock:
558 mutex_unlock(&dynamic_netconsole_mutex);
559 return -EINVAL;
560}
561
562static ssize_t remote_mac_store(struct config_item *item, const char *buf,
563 size_t count)
564{
565 struct netconsole_target *nt = to_target(item);
566 u8 remote_mac[ETH_ALEN];
567
568 mutex_lock(&dynamic_netconsole_mutex);
569 if (nt->enabled) {
570 pr_err("target (%s) is enabled, disable to update parameters\n",
571 config_item_name(&nt->item));
572 goto out_unlock;
573 }
574
575 if (!mac_pton(buf, remote_mac))
576 goto out_unlock;
577 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
578 goto out_unlock;
579 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
580
581 mutex_unlock(&dynamic_netconsole_mutex);
582 return strnlen(buf, count);
583out_unlock:
584 mutex_unlock(&dynamic_netconsole_mutex);
585 return -EINVAL;
586}
587
588CONFIGFS_ATTR(, enabled);
589CONFIGFS_ATTR(, extended);
590CONFIGFS_ATTR(, dev_name);
591CONFIGFS_ATTR(, local_port);
592CONFIGFS_ATTR(, remote_port);
593CONFIGFS_ATTR(, local_ip);
594CONFIGFS_ATTR(, remote_ip);
595CONFIGFS_ATTR_RO(, local_mac);
596CONFIGFS_ATTR(, remote_mac);
597CONFIGFS_ATTR(, release);
598
599static struct configfs_attribute *netconsole_target_attrs[] = {
600 &attr_enabled,
601 &attr_extended,
602 &attr_release,
603 &attr_dev_name,
604 &attr_local_port,
605 &attr_remote_port,
606 &attr_local_ip,
607 &attr_remote_ip,
608 &attr_local_mac,
609 &attr_remote_mac,
610 NULL,
611};
612
613/*
614 * Item operations and type for netconsole_target.
615 */
616
617static void netconsole_target_release(struct config_item *item)
618{
619 kfree(to_target(item));
620}
621
622static struct configfs_item_operations netconsole_target_item_ops = {
623 .release = netconsole_target_release,
624};
625
626static const struct config_item_type netconsole_target_type = {
627 .ct_attrs = netconsole_target_attrs,
628 .ct_item_ops = &netconsole_target_item_ops,
629 .ct_owner = THIS_MODULE,
630};
631
632static struct netconsole_target *find_cmdline_target(const char *name)
633{
634 struct netconsole_target *nt, *ret = NULL;
635 unsigned long flags;
636
637 spin_lock_irqsave(&target_list_lock, flags);
638 list_for_each_entry(nt, &target_list, list) {
639 if (!strcmp(nt->item.ci_name, name)) {
640 ret = nt;
641 break;
642 }
643 }
644 spin_unlock_irqrestore(&target_list_lock, flags);
645
646 return ret;
647}
648
649/*
650 * Group operations and type for netconsole_subsys.
651 */
652
653static struct config_item *make_netconsole_target(struct config_group *group,
654 const char *name)
655{
656 struct netconsole_target *nt;
657 unsigned long flags;
658
659 /* Checking if a target by this name was created at boot time. If so,
660 * attach a configfs entry to that target. This enables dynamic
661 * control.
662 */
663 if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX,
664 strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
665 nt = find_cmdline_target(name);
666 if (nt)
667 return &nt->item;
668 }
669
670 nt = alloc_and_init();
671 if (!nt)
672 return ERR_PTR(-ENOMEM);
673
674 /* Initialize the config_item member */
675 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
676
677 /* Adding, but it is disabled */
678 spin_lock_irqsave(&target_list_lock, flags);
679 list_add(&nt->list, &target_list);
680 spin_unlock_irqrestore(&target_list_lock, flags);
681
682 return &nt->item;
683}
684
685static void drop_netconsole_target(struct config_group *group,
686 struct config_item *item)
687{
688 unsigned long flags;
689 struct netconsole_target *nt = to_target(item);
690
691 spin_lock_irqsave(&target_list_lock, flags);
692 list_del(&nt->list);
693 spin_unlock_irqrestore(&target_list_lock, flags);
694
695 /*
696 * The target may have never been enabled, or was manually disabled
697 * before being removed so netpoll may have already been cleaned up.
698 */
699 if (nt->enabled)
700 netpoll_cleanup(&nt->np);
701
702 config_item_put(&nt->item);
703}
704
705static struct configfs_group_operations netconsole_subsys_group_ops = {
706 .make_item = make_netconsole_target,
707 .drop_item = drop_netconsole_target,
708};
709
710static const struct config_item_type netconsole_subsys_type = {
711 .ct_group_ops = &netconsole_subsys_group_ops,
712 .ct_owner = THIS_MODULE,
713};
714
715/* The netconsole configfs subsystem */
716static struct configfs_subsystem netconsole_subsys = {
717 .su_group = {
718 .cg_item = {
719 .ci_namebuf = "netconsole",
720 .ci_type = &netconsole_subsys_type,
721 },
722 },
723};
724
725static void populate_configfs_item(struct netconsole_target *nt,
726 int cmdline_count)
727{
728 char target_name[16];
729
730 snprintf(target_name, sizeof(target_name), "%s%d",
731 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
732 config_item_init_type_name(&nt->item, target_name,
733 &netconsole_target_type);
734}
735
736#endif /* CONFIG_NETCONSOLE_DYNAMIC */
737
738/* Handle network interface device notifications */
739static int netconsole_netdev_event(struct notifier_block *this,
740 unsigned long event, void *ptr)
741{
742 unsigned long flags;
743 struct netconsole_target *nt;
744 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
745 bool stopped = false;
746
747 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
748 event == NETDEV_RELEASE || event == NETDEV_JOIN))
749 goto done;
750
751 spin_lock_irqsave(&target_list_lock, flags);
752restart:
753 list_for_each_entry(nt, &target_list, list) {
754 netconsole_target_get(nt);
755 if (nt->np.dev == dev) {
756 switch (event) {
757 case NETDEV_CHANGENAME:
758 strscpy(nt->np.dev_name, dev->name, IFNAMSIZ);
759 break;
760 case NETDEV_RELEASE:
761 case NETDEV_JOIN:
762 case NETDEV_UNREGISTER:
763 /* rtnl_lock already held
764 * we might sleep in __netpoll_cleanup()
765 */
766 spin_unlock_irqrestore(&target_list_lock, flags);
767
768 __netpoll_cleanup(&nt->np);
769
770 spin_lock_irqsave(&target_list_lock, flags);
771 netdev_put(nt->np.dev, &nt->np.dev_tracker);
772 nt->np.dev = NULL;
773 nt->enabled = false;
774 stopped = true;
775 netconsole_target_put(nt);
776 goto restart;
777 }
778 }
779 netconsole_target_put(nt);
780 }
781 spin_unlock_irqrestore(&target_list_lock, flags);
782 if (stopped) {
783 const char *msg = "had an event";
784 switch (event) {
785 case NETDEV_UNREGISTER:
786 msg = "unregistered";
787 break;
788 case NETDEV_RELEASE:
789 msg = "released slaves";
790 break;
791 case NETDEV_JOIN:
792 msg = "is joining a master device";
793 break;
794 }
795 pr_info("network logging stopped on interface %s as it %s\n",
796 dev->name, msg);
797 }
798
799done:
800 return NOTIFY_DONE;
801}
802
803static struct notifier_block netconsole_netdev_notifier = {
804 .notifier_call = netconsole_netdev_event,
805};
806
807/**
808 * send_ext_msg_udp - send extended log message to target
809 * @nt: target to send message to
810 * @msg: extended log message to send
811 * @msg_len: length of message
812 *
813 * Transfer extended log @msg to @nt. If @msg is longer than
814 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
815 * ncfrag header field added to identify them.
816 */
817static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
818 int msg_len)
819{
820 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
821 const char *header, *body;
822 int offset = 0;
823 int header_len, body_len;
824 const char *msg_ready = msg;
825 const char *release;
826 int release_len = 0;
827
828 if (nt->release) {
829 release = init_utsname()->release;
830 release_len = strlen(release) + 1;
831 }
832
833 if (msg_len + release_len <= MAX_PRINT_CHUNK) {
834 /* No fragmentation needed */
835 if (nt->release) {
836 scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg);
837 msg_len += release_len;
838 msg_ready = buf;
839 }
840 netpoll_send_udp(&nt->np, msg_ready, msg_len);
841 return;
842 }
843
844 /* need to insert extra header fields, detect header and body */
845 header = msg;
846 body = memchr(msg, ';', msg_len);
847 if (WARN_ON_ONCE(!body))
848 return;
849
850 header_len = body - header;
851 body_len = msg_len - header_len - 1;
852 body++;
853
854 /*
855 * Transfer multiple chunks with the following extra header.
856 * "ncfrag=<byte-offset>/<total-bytes>"
857 */
858 if (nt->release)
859 scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
860 memcpy(buf + release_len, header, header_len);
861 header_len += release_len;
862
863 while (offset < body_len) {
864 int this_header = header_len;
865 int this_chunk;
866
867 this_header += scnprintf(buf + this_header,
868 sizeof(buf) - this_header,
869 ",ncfrag=%d/%d;", offset, body_len);
870
871 this_chunk = min(body_len - offset,
872 MAX_PRINT_CHUNK - this_header);
873 if (WARN_ON_ONCE(this_chunk <= 0))
874 return;
875
876 memcpy(buf + this_header, body + offset, this_chunk);
877
878 netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
879
880 offset += this_chunk;
881 }
882}
883
884static void write_ext_msg(struct console *con, const char *msg,
885 unsigned int len)
886{
887 struct netconsole_target *nt;
888 unsigned long flags;
889
890 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
891 return;
892
893 spin_lock_irqsave(&target_list_lock, flags);
894 list_for_each_entry(nt, &target_list, list)
895 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
896 send_ext_msg_udp(nt, msg, len);
897 spin_unlock_irqrestore(&target_list_lock, flags);
898}
899
900static void write_msg(struct console *con, const char *msg, unsigned int len)
901{
902 int frag, left;
903 unsigned long flags;
904 struct netconsole_target *nt;
905 const char *tmp;
906
907 if (oops_only && !oops_in_progress)
908 return;
909 /* Avoid taking lock and disabling interrupts unnecessarily */
910 if (list_empty(&target_list))
911 return;
912
913 spin_lock_irqsave(&target_list_lock, flags);
914 list_for_each_entry(nt, &target_list, list) {
915 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
916 /*
917 * We nest this inside the for-each-target loop above
918 * so that we're able to get as much logging out to
919 * at least one target if we die inside here, instead
920 * of unnecessarily keeping all targets in lock-step.
921 */
922 tmp = msg;
923 for (left = len; left;) {
924 frag = min(left, MAX_PRINT_CHUNK);
925 netpoll_send_udp(&nt->np, tmp, frag);
926 tmp += frag;
927 left -= frag;
928 }
929 }
930 }
931 spin_unlock_irqrestore(&target_list_lock, flags);
932}
933
934/* Allocate new target (from boot/module param) and setup netpoll for it */
935static struct netconsole_target *alloc_param_target(char *target_config,
936 int cmdline_count)
937{
938 struct netconsole_target *nt;
939 int err;
940
941 nt = alloc_and_init();
942 if (!nt) {
943 err = -ENOMEM;
944 goto fail;
945 }
946
947 if (*target_config == '+') {
948 nt->extended = true;
949 target_config++;
950 }
951
952 if (*target_config == 'r') {
953 if (!nt->extended) {
954 pr_err("Netconsole configuration error. Release feature requires extended log message");
955 err = -EINVAL;
956 goto fail;
957 }
958 nt->release = true;
959 target_config++;
960 }
961
962 /* Parse parameters and setup netpoll */
963 err = netpoll_parse_options(&nt->np, target_config);
964 if (err)
965 goto fail;
966
967 err = netpoll_setup(&nt->np);
968 if (err)
969 goto fail;
970
971 populate_configfs_item(nt, cmdline_count);
972 nt->enabled = true;
973
974 return nt;
975
976fail:
977 kfree(nt);
978 return ERR_PTR(err);
979}
980
981/* Cleanup netpoll for given target (from boot/module param) and free it */
982static void free_param_target(struct netconsole_target *nt)
983{
984 netpoll_cleanup(&nt->np);
985 kfree(nt);
986}
987
988static struct console netconsole_ext = {
989 .name = "netcon_ext",
990 .flags = CON_ENABLED | CON_EXTENDED,
991 .write = write_ext_msg,
992};
993
994static struct console netconsole = {
995 .name = "netcon",
996 .flags = CON_ENABLED,
997 .write = write_msg,
998};
999
1000static int __init init_netconsole(void)
1001{
1002 int err;
1003 struct netconsole_target *nt, *tmp;
1004 unsigned int count = 0;
1005 bool extended = false;
1006 unsigned long flags;
1007 char *target_config;
1008 char *input = config;
1009
1010 if (strnlen(input, MAX_PARAM_LENGTH)) {
1011 while ((target_config = strsep(&input, ";"))) {
1012 nt = alloc_param_target(target_config, count);
1013 if (IS_ERR(nt)) {
1014 err = PTR_ERR(nt);
1015 goto fail;
1016 }
1017 /* Dump existing printks when we register */
1018 if (nt->extended) {
1019 extended = true;
1020 netconsole_ext.flags |= CON_PRINTBUFFER;
1021 } else {
1022 netconsole.flags |= CON_PRINTBUFFER;
1023 }
1024
1025 spin_lock_irqsave(&target_list_lock, flags);
1026 list_add(&nt->list, &target_list);
1027 spin_unlock_irqrestore(&target_list_lock, flags);
1028 count++;
1029 }
1030 }
1031
1032 err = register_netdevice_notifier(&netconsole_netdev_notifier);
1033 if (err)
1034 goto fail;
1035
1036 err = dynamic_netconsole_init();
1037 if (err)
1038 goto undonotifier;
1039
1040 if (extended)
1041 register_console(&netconsole_ext);
1042 register_console(&netconsole);
1043 pr_info("network logging started\n");
1044
1045 return err;
1046
1047undonotifier:
1048 unregister_netdevice_notifier(&netconsole_netdev_notifier);
1049
1050fail:
1051 pr_err("cleaning up\n");
1052
1053 /*
1054 * Remove all targets and destroy them (only targets created
1055 * from the boot/module option exist here). Skipping the list
1056 * lock is safe here, and netpoll_cleanup() will sleep.
1057 */
1058 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1059 list_del(&nt->list);
1060 free_param_target(nt);
1061 }
1062
1063 return err;
1064}
1065
1066static void __exit cleanup_netconsole(void)
1067{
1068 struct netconsole_target *nt, *tmp;
1069
1070 if (console_is_registered(&netconsole_ext))
1071 unregister_console(&netconsole_ext);
1072 unregister_console(&netconsole);
1073 dynamic_netconsole_exit();
1074 unregister_netdevice_notifier(&netconsole_netdev_notifier);
1075
1076 /*
1077 * Targets created via configfs pin references on our module
1078 * and would first be rmdir(2)'ed from userspace. We reach
1079 * here only when they are already destroyed, and only those
1080 * created from the boot/module option are left, so remove and
1081 * destroy them. Skipping the list lock is safe here, and
1082 * netpoll_cleanup() will sleep.
1083 */
1084 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1085 list_del(&nt->list);
1086 free_param_target(nt);
1087 }
1088}
1089
1090/*
1091 * Use late_initcall to ensure netconsole is
1092 * initialized after network device driver if built-in.
1093 *
1094 * late_initcall() and module_init() are identical if built as module.
1095 */
1096late_initcall(init_netconsole);
1097module_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 strscpy(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 strscpy(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 && !console_is_registered(&netconsole_ext))
336 register_console(&netconsole_ext);
337
338 /*
339 * Skip netpoll_parse_options() -- all the attributes are
340 * already configured via configfs. Just print them out.
341 */
342 netpoll_print_options(&nt->np);
343
344 err = netpoll_setup(&nt->np);
345 if (err)
346 goto out_unlock;
347
348 pr_info("network logging started\n");
349 } else { /* false */
350 /* We need to disable the netconsole before cleaning it up
351 * otherwise we might end up in write_msg() with
352 * nt->np.dev == NULL and nt->enabled == true
353 */
354 spin_lock_irqsave(&target_list_lock, flags);
355 nt->enabled = false;
356 spin_unlock_irqrestore(&target_list_lock, flags);
357 netpoll_cleanup(&nt->np);
358 }
359
360 nt->enabled = enabled;
361
362 mutex_unlock(&dynamic_netconsole_mutex);
363 return strnlen(buf, count);
364out_unlock:
365 mutex_unlock(&dynamic_netconsole_mutex);
366 return err;
367}
368
369static ssize_t extended_store(struct config_item *item, const char *buf,
370 size_t count)
371{
372 struct netconsole_target *nt = to_target(item);
373 int extended;
374 int err;
375
376 mutex_lock(&dynamic_netconsole_mutex);
377 if (nt->enabled) {
378 pr_err("target (%s) is enabled, disable to update parameters\n",
379 config_item_name(&nt->item));
380 err = -EINVAL;
381 goto out_unlock;
382 }
383
384 err = kstrtoint(buf, 10, &extended);
385 if (err < 0)
386 goto out_unlock;
387 if (extended < 0 || extended > 1) {
388 err = -EINVAL;
389 goto out_unlock;
390 }
391
392 nt->extended = extended;
393
394 mutex_unlock(&dynamic_netconsole_mutex);
395 return strnlen(buf, count);
396out_unlock:
397 mutex_unlock(&dynamic_netconsole_mutex);
398 return err;
399}
400
401static ssize_t dev_name_store(struct config_item *item, const char *buf,
402 size_t count)
403{
404 struct netconsole_target *nt = to_target(item);
405 size_t len;
406
407 mutex_lock(&dynamic_netconsole_mutex);
408 if (nt->enabled) {
409 pr_err("target (%s) is enabled, disable to update parameters\n",
410 config_item_name(&nt->item));
411 mutex_unlock(&dynamic_netconsole_mutex);
412 return -EINVAL;
413 }
414
415 strscpy(nt->np.dev_name, buf, IFNAMSIZ);
416
417 /* Get rid of possible trailing newline from echo(1) */
418 len = strnlen(nt->np.dev_name, IFNAMSIZ);
419 if (nt->np.dev_name[len - 1] == '\n')
420 nt->np.dev_name[len - 1] = '\0';
421
422 mutex_unlock(&dynamic_netconsole_mutex);
423 return strnlen(buf, count);
424}
425
426static ssize_t local_port_store(struct config_item *item, const char *buf,
427 size_t count)
428{
429 struct netconsole_target *nt = to_target(item);
430 int rv = -EINVAL;
431
432 mutex_lock(&dynamic_netconsole_mutex);
433 if (nt->enabled) {
434 pr_err("target (%s) is enabled, disable to update parameters\n",
435 config_item_name(&nt->item));
436 goto out_unlock;
437 }
438
439 rv = kstrtou16(buf, 10, &nt->np.local_port);
440 if (rv < 0)
441 goto out_unlock;
442 mutex_unlock(&dynamic_netconsole_mutex);
443 return strnlen(buf, count);
444out_unlock:
445 mutex_unlock(&dynamic_netconsole_mutex);
446 return rv;
447}
448
449static ssize_t remote_port_store(struct config_item *item,
450 const char *buf, size_t count)
451{
452 struct netconsole_target *nt = to_target(item);
453 int rv = -EINVAL;
454
455 mutex_lock(&dynamic_netconsole_mutex);
456 if (nt->enabled) {
457 pr_err("target (%s) is enabled, disable to update parameters\n",
458 config_item_name(&nt->item));
459 goto out_unlock;
460 }
461
462 rv = kstrtou16(buf, 10, &nt->np.remote_port);
463 if (rv < 0)
464 goto out_unlock;
465 mutex_unlock(&dynamic_netconsole_mutex);
466 return strnlen(buf, count);
467out_unlock:
468 mutex_unlock(&dynamic_netconsole_mutex);
469 return rv;
470}
471
472static ssize_t local_ip_store(struct config_item *item, const char *buf,
473 size_t count)
474{
475 struct netconsole_target *nt = to_target(item);
476
477 mutex_lock(&dynamic_netconsole_mutex);
478 if (nt->enabled) {
479 pr_err("target (%s) is enabled, disable to update parameters\n",
480 config_item_name(&nt->item));
481 goto out_unlock;
482 }
483
484 if (strnchr(buf, count, ':')) {
485 const char *end;
486 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
487 if (*end && *end != '\n') {
488 pr_err("invalid IPv6 address at: <%c>\n", *end);
489 goto out_unlock;
490 }
491 nt->np.ipv6 = true;
492 } else
493 goto out_unlock;
494 } else {
495 if (!nt->np.ipv6) {
496 nt->np.local_ip.ip = in_aton(buf);
497 } else
498 goto out_unlock;
499 }
500
501 mutex_unlock(&dynamic_netconsole_mutex);
502 return strnlen(buf, count);
503out_unlock:
504 mutex_unlock(&dynamic_netconsole_mutex);
505 return -EINVAL;
506}
507
508static ssize_t remote_ip_store(struct config_item *item, const char *buf,
509 size_t count)
510{
511 struct netconsole_target *nt = to_target(item);
512
513 mutex_lock(&dynamic_netconsole_mutex);
514 if (nt->enabled) {
515 pr_err("target (%s) is enabled, disable to update parameters\n",
516 config_item_name(&nt->item));
517 goto out_unlock;
518 }
519
520 if (strnchr(buf, count, ':')) {
521 const char *end;
522 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
523 if (*end && *end != '\n') {
524 pr_err("invalid IPv6 address at: <%c>\n", *end);
525 goto out_unlock;
526 }
527 nt->np.ipv6 = true;
528 } else
529 goto out_unlock;
530 } else {
531 if (!nt->np.ipv6) {
532 nt->np.remote_ip.ip = in_aton(buf);
533 } else
534 goto out_unlock;
535 }
536
537 mutex_unlock(&dynamic_netconsole_mutex);
538 return strnlen(buf, count);
539out_unlock:
540 mutex_unlock(&dynamic_netconsole_mutex);
541 return -EINVAL;
542}
543
544static ssize_t remote_mac_store(struct config_item *item, const char *buf,
545 size_t count)
546{
547 struct netconsole_target *nt = to_target(item);
548 u8 remote_mac[ETH_ALEN];
549
550 mutex_lock(&dynamic_netconsole_mutex);
551 if (nt->enabled) {
552 pr_err("target (%s) is enabled, disable to update parameters\n",
553 config_item_name(&nt->item));
554 goto out_unlock;
555 }
556
557 if (!mac_pton(buf, remote_mac))
558 goto out_unlock;
559 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
560 goto out_unlock;
561 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
562
563 mutex_unlock(&dynamic_netconsole_mutex);
564 return strnlen(buf, count);
565out_unlock:
566 mutex_unlock(&dynamic_netconsole_mutex);
567 return -EINVAL;
568}
569
570CONFIGFS_ATTR(, enabled);
571CONFIGFS_ATTR(, extended);
572CONFIGFS_ATTR(, dev_name);
573CONFIGFS_ATTR(, local_port);
574CONFIGFS_ATTR(, remote_port);
575CONFIGFS_ATTR(, local_ip);
576CONFIGFS_ATTR(, remote_ip);
577CONFIGFS_ATTR_RO(, local_mac);
578CONFIGFS_ATTR(, remote_mac);
579
580static struct configfs_attribute *netconsole_target_attrs[] = {
581 &attr_enabled,
582 &attr_extended,
583 &attr_dev_name,
584 &attr_local_port,
585 &attr_remote_port,
586 &attr_local_ip,
587 &attr_remote_ip,
588 &attr_local_mac,
589 &attr_remote_mac,
590 NULL,
591};
592
593/*
594 * Item operations and type for netconsole_target.
595 */
596
597static void netconsole_target_release(struct config_item *item)
598{
599 kfree(to_target(item));
600}
601
602static struct configfs_item_operations netconsole_target_item_ops = {
603 .release = netconsole_target_release,
604};
605
606static const struct config_item_type netconsole_target_type = {
607 .ct_attrs = netconsole_target_attrs,
608 .ct_item_ops = &netconsole_target_item_ops,
609 .ct_owner = THIS_MODULE,
610};
611
612/*
613 * Group operations and type for netconsole_subsys.
614 */
615
616static struct config_item *make_netconsole_target(struct config_group *group,
617 const char *name)
618{
619 unsigned long flags;
620 struct netconsole_target *nt;
621
622 /*
623 * Allocate and initialize with defaults.
624 * Target is disabled at creation (!enabled).
625 */
626 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
627 if (!nt)
628 return ERR_PTR(-ENOMEM);
629
630 nt->np.name = "netconsole";
631 strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
632 nt->np.local_port = 6665;
633 nt->np.remote_port = 6666;
634 eth_broadcast_addr(nt->np.remote_mac);
635
636 /* Initialize the config_item member */
637 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
638
639 /* Adding, but it is disabled */
640 spin_lock_irqsave(&target_list_lock, flags);
641 list_add(&nt->list, &target_list);
642 spin_unlock_irqrestore(&target_list_lock, flags);
643
644 return &nt->item;
645}
646
647static void drop_netconsole_target(struct config_group *group,
648 struct config_item *item)
649{
650 unsigned long flags;
651 struct netconsole_target *nt = to_target(item);
652
653 spin_lock_irqsave(&target_list_lock, flags);
654 list_del(&nt->list);
655 spin_unlock_irqrestore(&target_list_lock, flags);
656
657 /*
658 * The target may have never been enabled, or was manually disabled
659 * before being removed so netpoll may have already been cleaned up.
660 */
661 if (nt->enabled)
662 netpoll_cleanup(&nt->np);
663
664 config_item_put(&nt->item);
665}
666
667static struct configfs_group_operations netconsole_subsys_group_ops = {
668 .make_item = make_netconsole_target,
669 .drop_item = drop_netconsole_target,
670};
671
672static const struct config_item_type netconsole_subsys_type = {
673 .ct_group_ops = &netconsole_subsys_group_ops,
674 .ct_owner = THIS_MODULE,
675};
676
677/* The netconsole configfs subsystem */
678static struct configfs_subsystem netconsole_subsys = {
679 .su_group = {
680 .cg_item = {
681 .ci_namebuf = "netconsole",
682 .ci_type = &netconsole_subsys_type,
683 },
684 },
685};
686
687#endif /* CONFIG_NETCONSOLE_DYNAMIC */
688
689/* Handle network interface device notifications */
690static int netconsole_netdev_event(struct notifier_block *this,
691 unsigned long event, void *ptr)
692{
693 unsigned long flags;
694 struct netconsole_target *nt;
695 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
696 bool stopped = false;
697
698 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
699 event == NETDEV_RELEASE || event == NETDEV_JOIN))
700 goto done;
701
702 spin_lock_irqsave(&target_list_lock, flags);
703restart:
704 list_for_each_entry(nt, &target_list, list) {
705 netconsole_target_get(nt);
706 if (nt->np.dev == dev) {
707 switch (event) {
708 case NETDEV_CHANGENAME:
709 strscpy(nt->np.dev_name, dev->name, IFNAMSIZ);
710 break;
711 case NETDEV_RELEASE:
712 case NETDEV_JOIN:
713 case NETDEV_UNREGISTER:
714 /* rtnl_lock already held
715 * we might sleep in __netpoll_cleanup()
716 */
717 spin_unlock_irqrestore(&target_list_lock, flags);
718
719 __netpoll_cleanup(&nt->np);
720
721 spin_lock_irqsave(&target_list_lock, flags);
722 netdev_put(nt->np.dev, &nt->np.dev_tracker);
723 nt->np.dev = NULL;
724 nt->enabled = false;
725 stopped = true;
726 netconsole_target_put(nt);
727 goto restart;
728 }
729 }
730 netconsole_target_put(nt);
731 }
732 spin_unlock_irqrestore(&target_list_lock, flags);
733 if (stopped) {
734 const char *msg = "had an event";
735 switch (event) {
736 case NETDEV_UNREGISTER:
737 msg = "unregistered";
738 break;
739 case NETDEV_RELEASE:
740 msg = "released slaves";
741 break;
742 case NETDEV_JOIN:
743 msg = "is joining a master device";
744 break;
745 }
746 pr_info("network logging stopped on interface %s as it %s\n",
747 dev->name, msg);
748 }
749
750done:
751 return NOTIFY_DONE;
752}
753
754static struct notifier_block netconsole_netdev_notifier = {
755 .notifier_call = netconsole_netdev_event,
756};
757
758/**
759 * send_ext_msg_udp - send extended log message to target
760 * @nt: target to send message to
761 * @msg: extended log message to send
762 * @msg_len: length of message
763 *
764 * Transfer extended log @msg to @nt. If @msg is longer than
765 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
766 * ncfrag header field added to identify them.
767 */
768static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
769 int msg_len)
770{
771 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
772 const char *header, *body;
773 int offset = 0;
774 int header_len, body_len;
775
776 if (msg_len <= MAX_PRINT_CHUNK) {
777 netpoll_send_udp(&nt->np, msg, msg_len);
778 return;
779 }
780
781 /* need to insert extra header fields, detect header and body */
782 header = msg;
783 body = memchr(msg, ';', msg_len);
784 if (WARN_ON_ONCE(!body))
785 return;
786
787 header_len = body - header;
788 body_len = msg_len - header_len - 1;
789 body++;
790
791 /*
792 * Transfer multiple chunks with the following extra header.
793 * "ncfrag=<byte-offset>/<total-bytes>"
794 */
795 memcpy(buf, header, header_len);
796
797 while (offset < body_len) {
798 int this_header = header_len;
799 int this_chunk;
800
801 this_header += scnprintf(buf + this_header,
802 sizeof(buf) - this_header,
803 ",ncfrag=%d/%d;", offset, body_len);
804
805 this_chunk = min(body_len - offset,
806 MAX_PRINT_CHUNK - this_header);
807 if (WARN_ON_ONCE(this_chunk <= 0))
808 return;
809
810 memcpy(buf + this_header, body + offset, this_chunk);
811
812 netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
813
814 offset += this_chunk;
815 }
816}
817
818static void write_ext_msg(struct console *con, const char *msg,
819 unsigned int len)
820{
821 struct netconsole_target *nt;
822 unsigned long flags;
823
824 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
825 return;
826
827 spin_lock_irqsave(&target_list_lock, flags);
828 list_for_each_entry(nt, &target_list, list)
829 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
830 send_ext_msg_udp(nt, msg, len);
831 spin_unlock_irqrestore(&target_list_lock, flags);
832}
833
834static void write_msg(struct console *con, const char *msg, unsigned int len)
835{
836 int frag, left;
837 unsigned long flags;
838 struct netconsole_target *nt;
839 const char *tmp;
840
841 if (oops_only && !oops_in_progress)
842 return;
843 /* Avoid taking lock and disabling interrupts unnecessarily */
844 if (list_empty(&target_list))
845 return;
846
847 spin_lock_irqsave(&target_list_lock, flags);
848 list_for_each_entry(nt, &target_list, list) {
849 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
850 /*
851 * We nest this inside the for-each-target loop above
852 * so that we're able to get as much logging out to
853 * at least one target if we die inside here, instead
854 * of unnecessarily keeping all targets in lock-step.
855 */
856 tmp = msg;
857 for (left = len; left;) {
858 frag = min(left, MAX_PRINT_CHUNK);
859 netpoll_send_udp(&nt->np, tmp, frag);
860 tmp += frag;
861 left -= frag;
862 }
863 }
864 }
865 spin_unlock_irqrestore(&target_list_lock, flags);
866}
867
868static struct console netconsole_ext = {
869 .name = "netcon_ext",
870 .flags = CON_ENABLED | CON_EXTENDED,
871 .write = write_ext_msg,
872};
873
874static struct console netconsole = {
875 .name = "netcon",
876 .flags = CON_ENABLED,
877 .write = write_msg,
878};
879
880static int __init init_netconsole(void)
881{
882 int err;
883 struct netconsole_target *nt, *tmp;
884 bool extended = false;
885 unsigned long flags;
886 char *target_config;
887 char *input = config;
888
889 if (strnlen(input, MAX_PARAM_LENGTH)) {
890 while ((target_config = strsep(&input, ";"))) {
891 nt = alloc_param_target(target_config);
892 if (IS_ERR(nt)) {
893 err = PTR_ERR(nt);
894 goto fail;
895 }
896 /* Dump existing printks when we register */
897 if (nt->extended) {
898 extended = true;
899 netconsole_ext.flags |= CON_PRINTBUFFER;
900 } else {
901 netconsole.flags |= CON_PRINTBUFFER;
902 }
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 (extended)
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 if (console_is_registered(&netconsole_ext))
949 unregister_console(&netconsole_ext);
950 unregister_console(&netconsole);
951 dynamic_netconsole_exit();
952 unregister_netdevice_notifier(&netconsole_netdev_notifier);
953
954 /*
955 * Targets created via configfs pin references on our module
956 * and would first be rmdir(2)'ed from userspace. We reach
957 * here only when they are already destroyed, and only those
958 * created from the boot/module option are left, so remove and
959 * destroy them. Skipping the list lock is safe here, and
960 * netpoll_cleanup() will sleep.
961 */
962 list_for_each_entry_safe(nt, tmp, &target_list, list) {
963 list_del(&nt->list);
964 free_param_target(nt);
965 }
966}
967
968/*
969 * Use late_initcall to ensure netconsole is
970 * initialized after network device driver if built-in.
971 *
972 * late_initcall() and module_init() are identical if built as module.
973 */
974late_initcall(init_netconsole);
975module_exit(cleanup_netconsole);