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