1/*
2 * linux/drivers/net/netconsole.c
3 *
4 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
5 *
6 * This file contains the implementation of an IRQ-safe, crash-safe
7 * kernel console implementation that outputs kernel messages to the
8 * network.
9 *
10 * Modification history:
11 *
12 * 2001-09-17 started by Ingo Molnar.
13 * 2003-08-11 2.6 port by Matt Mackall
14 * simplified options
15 * generic card hooks
16 * works non-modular
17 * 2003-09-07 rewritten with netpoll api
18 */
19
20/****************************************************************
21 * This program is free software; you can redistribute it and/or modify
22 * it under the terms of the GNU General Public License as published by
23 * the Free Software Foundation; either version 2, or (at your option)
24 * any later version.
25 *
26 * This program is distributed in the hope that it will be useful,
27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
29 * GNU General Public License for more details.
30 *
31 * You should have received a copy of the GNU General Public License
32 * along with this program; if not, write to the Free Software
33 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
34 *
35 ****************************************************************/
36
37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39#include <linux/mm.h>
40#include <linux/init.h>
41#include <linux/module.h>
42#include <linux/slab.h>
43#include <linux/console.h>
44#include <linux/moduleparam.h>
45#include <linux/kernel.h>
46#include <linux/string.h>
47#include <linux/netpoll.h>
48#include <linux/inet.h>
49#include <linux/configfs.h>
50#include <linux/etherdevice.h>
51
52MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
53MODULE_DESCRIPTION("Console driver for network interfaces");
54MODULE_LICENSE("GPL");
55
56#define MAX_PARAM_LENGTH 256
57#define MAX_PRINT_CHUNK 1000
58
59static char config[MAX_PARAM_LENGTH];
60module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
61MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
62
63static bool oops_only = false;
64module_param(oops_only, bool, 0600);
65MODULE_PARM_DESC(oops_only, "Only log oops messages");
66
67#ifndef MODULE
68static int __init option_setup(char *opt)
69{
70 strlcpy(config, opt, MAX_PARAM_LENGTH);
71 return 1;
72}
73__setup("netconsole=", option_setup);
74#endif /* MODULE */
75
76/* Linked list of all configured targets */
77static LIST_HEAD(target_list);
78
79/* This needs to be a spinlock because write_msg() cannot sleep */
80static DEFINE_SPINLOCK(target_list_lock);
81
82/*
83 * Console driver for extended netconsoles. Registered on the first use to
84 * avoid unnecessarily enabling ext message formatting.
85 */
86static struct console netconsole_ext;
87
88/**
89 * struct netconsole_target - Represents a configured netconsole target.
90 * @list: Links this target into the target_list.
91 * @item: Links us into the configfs subsystem hierarchy.
92 * @enabled: On / off knob to enable / disable target.
93 * Visible from userspace (read-write).
94 * We maintain a strict 1:1 correspondence between this and
95 * whether the corresponding netpoll is active or inactive.
96 * Also, other parameters of a target may be modified at
97 * runtime only when it is disabled (enabled == 0).
98 * @np: The netpoll structure for this target.
99 * Contains the other userspace visible parameters:
100 * dev_name (read-write)
101 * local_port (read-write)
102 * remote_port (read-write)
103 * local_ip (read-write)
104 * remote_ip (read-write)
105 * local_mac (read-only)
106 * remote_mac (read-write)
107 */
108struct netconsole_target {
109 struct list_head list;
110#ifdef CONFIG_NETCONSOLE_DYNAMIC
111 struct config_item item;
112#endif
113 bool enabled;
114 bool extended;
115 struct netpoll np;
116};
117
118#ifdef CONFIG_NETCONSOLE_DYNAMIC
119
120static struct configfs_subsystem netconsole_subsys;
121static DEFINE_MUTEX(dynamic_netconsole_mutex);
122
123static int __init dynamic_netconsole_init(void)
124{
125 config_group_init(&netconsole_subsys.su_group);
126 mutex_init(&netconsole_subsys.su_mutex);
127 return configfs_register_subsystem(&netconsole_subsys);
128}
129
130static void __exit dynamic_netconsole_exit(void)
131{
132 configfs_unregister_subsystem(&netconsole_subsys);
133}
134
135/*
136 * Targets that were created by parsing the boot/module option string
137 * do not exist in the configfs hierarchy (and have NULL names) and will
138 * never go away, so make these a no-op for them.
139 */
140static void netconsole_target_get(struct netconsole_target *nt)
141{
142 if (config_item_name(&nt->item))
143 config_item_get(&nt->item);
144}
145
146static void netconsole_target_put(struct netconsole_target *nt)
147{
148 if (config_item_name(&nt->item))
149 config_item_put(&nt->item);
150}
151
152#else /* !CONFIG_NETCONSOLE_DYNAMIC */
153
154static int __init dynamic_netconsole_init(void)
155{
156 return 0;
157}
158
159static void __exit dynamic_netconsole_exit(void)
160{
161}
162
163/*
164 * No danger of targets going away from under us when dynamic
165 * reconfigurability is off.
166 */
167static void netconsole_target_get(struct netconsole_target *nt)
168{
169}
170
171static void netconsole_target_put(struct netconsole_target *nt)
172{
173}
174
175#endif /* CONFIG_NETCONSOLE_DYNAMIC */
176
177/* Allocate new target (from boot/module param) and setup netpoll for it */
178static struct netconsole_target *alloc_param_target(char *target_config)
179{
180 int err = -ENOMEM;
181 struct netconsole_target *nt;
182
183 /*
184 * Allocate and initialize with defaults.
185 * Note that these targets get their config_item fields zeroed-out.
186 */
187 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
188 if (!nt)
189 goto fail;
190
191 nt->np.name = "netconsole";
192 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
193 nt->np.local_port = 6665;
194 nt->np.remote_port = 6666;
195 eth_broadcast_addr(nt->np.remote_mac);
196
197 if (*target_config == '+') {
198 nt->extended = true;
199 target_config++;
200 }
201
202 /* Parse parameters and setup netpoll */
203 err = netpoll_parse_options(&nt->np, target_config);
204 if (err)
205 goto fail;
206
207 err = netpoll_setup(&nt->np);
208 if (err)
209 goto fail;
210
211 nt->enabled = true;
212
213 return nt;
214
215fail:
216 kfree(nt);
217 return ERR_PTR(err);
218}
219
220/* Cleanup netpoll for given target (from boot/module param) and free it */
221static void free_param_target(struct netconsole_target *nt)
222{
223 netpoll_cleanup(&nt->np);
224 kfree(nt);
225}
226
227#ifdef CONFIG_NETCONSOLE_DYNAMIC
228
229/*
230 * Our subsystem hierarchy is:
231 *
232 * /sys/kernel/config/netconsole/
233 * |
234 * <target>/
235 * | enabled
236 * | dev_name
237 * | local_port
238 * | remote_port
239 * | local_ip
240 * | remote_ip
241 * | local_mac
242 * | remote_mac
243 * |
244 * <target>/...
245 */
246
247static struct netconsole_target *to_target(struct config_item *item)
248{
249 return item ?
250 container_of(item, struct netconsole_target, item) :
251 NULL;
252}
253
254/*
255 * Attribute operations for netconsole_target.
256 */
257
258static ssize_t enabled_show(struct config_item *item, char *buf)
259{
260 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->enabled);
261}
262
263static ssize_t extended_show(struct config_item *item, char *buf)
264{
265 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->extended);
266}
267
268static ssize_t dev_name_show(struct config_item *item, char *buf)
269{
270 return snprintf(buf, PAGE_SIZE, "%s\n", to_target(item)->np.dev_name);
271}
272
273static ssize_t local_port_show(struct config_item *item, char *buf)
274{
275 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.local_port);
276}
277
278static ssize_t remote_port_show(struct config_item *item, char *buf)
279{
280 return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.remote_port);
281}
282
283static ssize_t local_ip_show(struct config_item *item, char *buf)
284{
285 struct netconsole_target *nt = to_target(item);
286
287 if (nt->np.ipv6)
288 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
289 else
290 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
291}
292
293static ssize_t remote_ip_show(struct config_item *item, char *buf)
294{
295 struct netconsole_target *nt = to_target(item);
296
297 if (nt->np.ipv6)
298 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
299 else
300 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
301}
302
303static ssize_t local_mac_show(struct config_item *item, char *buf)
304{
305 struct net_device *dev = to_target(item)->np.dev;
306 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
307
308 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
309}
310
311static ssize_t remote_mac_show(struct config_item *item, char *buf)
312{
313 return snprintf(buf, PAGE_SIZE, "%pM\n", to_target(item)->np.remote_mac);
314}
315
316/*
317 * This one is special -- targets created through the configfs interface
318 * are not enabled (and the corresponding netpoll activated) by default.
319 * The user is expected to set the desired parameters first (which
320 * would enable him to dynamically add new netpoll targets for new
321 * network interfaces as and when they come up).
322 */
323static ssize_t enabled_store(struct config_item *item,
324 const char *buf, size_t count)
325{
326 struct netconsole_target *nt = to_target(item);
327 unsigned long flags;
328 int enabled;
329 int err;
330
331 mutex_lock(&dynamic_netconsole_mutex);
332 err = kstrtoint(buf, 10, &enabled);
333 if (err < 0)
334 goto out_unlock;
335
336 err = -EINVAL;
337 if (enabled < 0 || enabled > 1)
338 goto out_unlock;
339 if ((bool)enabled == nt->enabled) {
340 pr_info("network logging has already %s\n",
341 nt->enabled ? "started" : "stopped");
342 goto out_unlock;
343 }
344
345 if (enabled) { /* true */
346 if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
347 netconsole_ext.flags |= CON_ENABLED;
348 register_console(&netconsole_ext);
349 }
350
351 /*
352 * Skip netpoll_parse_options() -- all the attributes are
353 * already configured via configfs. Just print them out.
354 */
355 netpoll_print_options(&nt->np);
356
357 err = netpoll_setup(&nt->np);
358 if (err)
359 goto out_unlock;
360
361 pr_info("network logging started\n");
362 } else { /* false */
363 /* We need to disable the netconsole before cleaning it up
364 * otherwise we might end up in write_msg() with
365 * nt->np.dev == NULL and nt->enabled == true
366 */
367 spin_lock_irqsave(&target_list_lock, flags);
368 nt->enabled = false;
369 spin_unlock_irqrestore(&target_list_lock, flags);
370 netpoll_cleanup(&nt->np);
371 }
372
373 nt->enabled = enabled;
374
375 mutex_unlock(&dynamic_netconsole_mutex);
376 return strnlen(buf, count);
377out_unlock:
378 mutex_unlock(&dynamic_netconsole_mutex);
379 return err;
380}
381
382static ssize_t extended_store(struct config_item *item, const char *buf,
383 size_t count)
384{
385 struct netconsole_target *nt = to_target(item);
386 int extended;
387 int err;
388
389 mutex_lock(&dynamic_netconsole_mutex);
390 if (nt->enabled) {
391 pr_err("target (%s) is enabled, disable to update parameters\n",
392 config_item_name(&nt->item));
393 err = -EINVAL;
394 goto out_unlock;
395 }
396
397 err = kstrtoint(buf, 10, &extended);
398 if (err < 0)
399 goto out_unlock;
400 if (extended < 0 || extended > 1) {
401 err = -EINVAL;
402 goto out_unlock;
403 }
404
405 nt->extended = extended;
406
407 mutex_unlock(&dynamic_netconsole_mutex);
408 return strnlen(buf, count);
409out_unlock:
410 mutex_unlock(&dynamic_netconsole_mutex);
411 return err;
412}
413
414static ssize_t dev_name_store(struct config_item *item, const char *buf,
415 size_t count)
416{
417 struct netconsole_target *nt = to_target(item);
418 size_t len;
419
420 mutex_lock(&dynamic_netconsole_mutex);
421 if (nt->enabled) {
422 pr_err("target (%s) is enabled, disable to update parameters\n",
423 config_item_name(&nt->item));
424 mutex_unlock(&dynamic_netconsole_mutex);
425 return -EINVAL;
426 }
427
428 strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
429
430 /* Get rid of possible trailing newline from echo(1) */
431 len = strnlen(nt->np.dev_name, IFNAMSIZ);
432 if (nt->np.dev_name[len - 1] == '\n')
433 nt->np.dev_name[len - 1] = '\0';
434
435 mutex_unlock(&dynamic_netconsole_mutex);
436 return strnlen(buf, count);
437}
438
439static ssize_t local_port_store(struct config_item *item, const char *buf,
440 size_t count)
441{
442 struct netconsole_target *nt = to_target(item);
443 int rv = -EINVAL;
444
445 mutex_lock(&dynamic_netconsole_mutex);
446 if (nt->enabled) {
447 pr_err("target (%s) is enabled, disable to update parameters\n",
448 config_item_name(&nt->item));
449 goto out_unlock;
450 }
451
452 rv = kstrtou16(buf, 10, &nt->np.local_port);
453 if (rv < 0)
454 goto out_unlock;
455 mutex_unlock(&dynamic_netconsole_mutex);
456 return strnlen(buf, count);
457out_unlock:
458 mutex_unlock(&dynamic_netconsole_mutex);
459 return rv;
460}
461
462static ssize_t remote_port_store(struct config_item *item,
463 const char *buf, size_t count)
464{
465 struct netconsole_target *nt = to_target(item);
466 int rv = -EINVAL;
467
468 mutex_lock(&dynamic_netconsole_mutex);
469 if (nt->enabled) {
470 pr_err("target (%s) is enabled, disable to update parameters\n",
471 config_item_name(&nt->item));
472 goto out_unlock;
473 }
474
475 rv = kstrtou16(buf, 10, &nt->np.remote_port);
476 if (rv < 0)
477 goto out_unlock;
478 mutex_unlock(&dynamic_netconsole_mutex);
479 return strnlen(buf, count);
480out_unlock:
481 mutex_unlock(&dynamic_netconsole_mutex);
482 return rv;
483}
484
485static ssize_t local_ip_store(struct config_item *item, const char *buf,
486 size_t count)
487{
488 struct netconsole_target *nt = to_target(item);
489
490 mutex_lock(&dynamic_netconsole_mutex);
491 if (nt->enabled) {
492 pr_err("target (%s) is enabled, disable to update parameters\n",
493 config_item_name(&nt->item));
494 goto out_unlock;
495 }
496
497 if (strnchr(buf, count, ':')) {
498 const char *end;
499 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
500 if (*end && *end != '\n') {
501 pr_err("invalid IPv6 address at: <%c>\n", *end);
502 goto out_unlock;
503 }
504 nt->np.ipv6 = true;
505 } else
506 goto out_unlock;
507 } else {
508 if (!nt->np.ipv6) {
509 nt->np.local_ip.ip = in_aton(buf);
510 } else
511 goto out_unlock;
512 }
513
514 mutex_unlock(&dynamic_netconsole_mutex);
515 return strnlen(buf, count);
516out_unlock:
517 mutex_unlock(&dynamic_netconsole_mutex);
518 return -EINVAL;
519}
520
521static ssize_t remote_ip_store(struct config_item *item, const char *buf,
522 size_t count)
523{
524 struct netconsole_target *nt = to_target(item);
525
526 mutex_lock(&dynamic_netconsole_mutex);
527 if (nt->enabled) {
528 pr_err("target (%s) is enabled, disable to update parameters\n",
529 config_item_name(&nt->item));
530 goto out_unlock;
531 }
532
533 if (strnchr(buf, count, ':')) {
534 const char *end;
535 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
536 if (*end && *end != '\n') {
537 pr_err("invalid IPv6 address at: <%c>\n", *end);
538 goto out_unlock;
539 }
540 nt->np.ipv6 = true;
541 } else
542 goto out_unlock;
543 } else {
544 if (!nt->np.ipv6) {
545 nt->np.remote_ip.ip = in_aton(buf);
546 } else
547 goto out_unlock;
548 }
549
550 mutex_unlock(&dynamic_netconsole_mutex);
551 return strnlen(buf, count);
552out_unlock:
553 mutex_unlock(&dynamic_netconsole_mutex);
554 return -EINVAL;
555}
556
557static ssize_t remote_mac_store(struct config_item *item, const char *buf,
558 size_t count)
559{
560 struct netconsole_target *nt = to_target(item);
561 u8 remote_mac[ETH_ALEN];
562
563 mutex_lock(&dynamic_netconsole_mutex);
564 if (nt->enabled) {
565 pr_err("target (%s) is enabled, disable to update parameters\n",
566 config_item_name(&nt->item));
567 goto out_unlock;
568 }
569
570 if (!mac_pton(buf, remote_mac))
571 goto out_unlock;
572 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
573 goto out_unlock;
574 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
575
576 mutex_unlock(&dynamic_netconsole_mutex);
577 return strnlen(buf, count);
578out_unlock:
579 mutex_unlock(&dynamic_netconsole_mutex);
580 return -EINVAL;
581}
582
583CONFIGFS_ATTR(, enabled);
584CONFIGFS_ATTR(, extended);
585CONFIGFS_ATTR(, dev_name);
586CONFIGFS_ATTR(, local_port);
587CONFIGFS_ATTR(, remote_port);
588CONFIGFS_ATTR(, local_ip);
589CONFIGFS_ATTR(, remote_ip);
590CONFIGFS_ATTR_RO(, local_mac);
591CONFIGFS_ATTR(, remote_mac);
592
593static struct configfs_attribute *netconsole_target_attrs[] = {
594 &attr_enabled,
595 &attr_extended,
596 &attr_dev_name,
597 &attr_local_port,
598 &attr_remote_port,
599 &attr_local_ip,
600 &attr_remote_ip,
601 &attr_local_mac,
602 &attr_remote_mac,
603 NULL,
604};
605
606/*
607 * Item operations and type for netconsole_target.
608 */
609
610static void netconsole_target_release(struct config_item *item)
611{
612 kfree(to_target(item));
613}
614
615static struct configfs_item_operations netconsole_target_item_ops = {
616 .release = netconsole_target_release,
617};
618
619static const struct config_item_type netconsole_target_type = {
620 .ct_attrs = netconsole_target_attrs,
621 .ct_item_ops = &netconsole_target_item_ops,
622 .ct_owner = THIS_MODULE,
623};
624
625/*
626 * Group operations and type for netconsole_subsys.
627 */
628
629static struct config_item *make_netconsole_target(struct config_group *group,
630 const char *name)
631{
632 unsigned long flags;
633 struct netconsole_target *nt;
634
635 /*
636 * Allocate and initialize with defaults.
637 * Target is disabled at creation (!enabled).
638 */
639 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
640 if (!nt)
641 return ERR_PTR(-ENOMEM);
642
643 nt->np.name = "netconsole";
644 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
645 nt->np.local_port = 6665;
646 nt->np.remote_port = 6666;
647 eth_broadcast_addr(nt->np.remote_mac);
648
649 /* Initialize the config_item member */
650 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
651
652 /* Adding, but it is disabled */
653 spin_lock_irqsave(&target_list_lock, flags);
654 list_add(&nt->list, &target_list);
655 spin_unlock_irqrestore(&target_list_lock, flags);
656
657 return &nt->item;
658}
659
660static void drop_netconsole_target(struct config_group *group,
661 struct config_item *item)
662{
663 unsigned long flags;
664 struct netconsole_target *nt = to_target(item);
665
666 spin_lock_irqsave(&target_list_lock, flags);
667 list_del(&nt->list);
668 spin_unlock_irqrestore(&target_list_lock, flags);
669
670 /*
671 * The target may have never been enabled, or was manually disabled
672 * before being removed so netpoll may have already been cleaned up.
673 */
674 if (nt->enabled)
675 netpoll_cleanup(&nt->np);
676
677 config_item_put(&nt->item);
678}
679
680static struct configfs_group_operations netconsole_subsys_group_ops = {
681 .make_item = make_netconsole_target,
682 .drop_item = drop_netconsole_target,
683};
684
685static const struct config_item_type netconsole_subsys_type = {
686 .ct_group_ops = &netconsole_subsys_group_ops,
687 .ct_owner = THIS_MODULE,
688};
689
690/* The netconsole configfs subsystem */
691static struct configfs_subsystem netconsole_subsys = {
692 .su_group = {
693 .cg_item = {
694 .ci_namebuf = "netconsole",
695 .ci_type = &netconsole_subsys_type,
696 },
697 },
698};
699
700#endif /* CONFIG_NETCONSOLE_DYNAMIC */
701
702/* Handle network interface device notifications */
703static int netconsole_netdev_event(struct notifier_block *this,
704 unsigned long event, void *ptr)
705{
706 unsigned long flags;
707 struct netconsole_target *nt;
708 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
709 bool stopped = false;
710
711 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
712 event == NETDEV_RELEASE || event == NETDEV_JOIN))
713 goto done;
714
715 spin_lock_irqsave(&target_list_lock, flags);
716restart:
717 list_for_each_entry(nt, &target_list, list) {
718 netconsole_target_get(nt);
719 if (nt->np.dev == dev) {
720 switch (event) {
721 case NETDEV_CHANGENAME:
722 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
723 break;
724 case NETDEV_RELEASE:
725 case NETDEV_JOIN:
726 case NETDEV_UNREGISTER:
727 /* rtnl_lock already held
728 * we might sleep in __netpoll_cleanup()
729 */
730 spin_unlock_irqrestore(&target_list_lock, flags);
731
732 __netpoll_cleanup(&nt->np);
733
734 spin_lock_irqsave(&target_list_lock, flags);
735 dev_put(nt->np.dev);
736 nt->np.dev = NULL;
737 nt->enabled = false;
738 stopped = true;
739 netconsole_target_put(nt);
740 goto restart;
741 }
742 }
743 netconsole_target_put(nt);
744 }
745 spin_unlock_irqrestore(&target_list_lock, flags);
746 if (stopped) {
747 const char *msg = "had an event";
748 switch (event) {
749 case NETDEV_UNREGISTER:
750 msg = "unregistered";
751 break;
752 case NETDEV_RELEASE:
753 msg = "released slaves";
754 break;
755 case NETDEV_JOIN:
756 msg = "is joining a master device";
757 break;
758 }
759 pr_info("network logging stopped on interface %s as it %s\n",
760 dev->name, msg);
761 }
762
763done:
764 return NOTIFY_DONE;
765}
766
767static struct notifier_block netconsole_netdev_notifier = {
768 .notifier_call = netconsole_netdev_event,
769};
770
771/**
772 * send_ext_msg_udp - send extended log message to target
773 * @nt: target to send message to
774 * @msg: extended log message to send
775 * @msg_len: length of message
776 *
777 * Transfer extended log @msg to @nt. If @msg is longer than
778 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
779 * ncfrag header field added to identify them.
780 */
781static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
782 int msg_len)
783{
784 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
785 const char *header, *body;
786 int offset = 0;
787 int header_len, body_len;
788
789 if (msg_len <= MAX_PRINT_CHUNK) {
790 netpoll_send_udp(&nt->np, msg, msg_len);
791 return;
792 }
793
794 /* need to insert extra header fields, detect header and body */
795 header = msg;
796 body = memchr(msg, ';', msg_len);
797 if (WARN_ON_ONCE(!body))
798 return;
799
800 header_len = body - header;
801 body_len = msg_len - header_len - 1;
802 body++;
803
804 /*
805 * Transfer multiple chunks with the following extra header.
806 * "ncfrag=<byte-offset>/<total-bytes>"
807 */
808 memcpy(buf, header, header_len);
809
810 while (offset < body_len) {
811 int this_header = header_len;
812 int this_chunk;
813
814 this_header += scnprintf(buf + this_header,
815 sizeof(buf) - this_header,
816 ",ncfrag=%d/%d;", offset, body_len);
817
818 this_chunk = min(body_len - offset,
819 MAX_PRINT_CHUNK - this_header);
820 if (WARN_ON_ONCE(this_chunk <= 0))
821 return;
822
823 memcpy(buf + this_header, body + offset, this_chunk);
824
825 netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
826
827 offset += this_chunk;
828 }
829}
830
831static void write_ext_msg(struct console *con, const char *msg,
832 unsigned int len)
833{
834 struct netconsole_target *nt;
835 unsigned long flags;
836
837 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
838 return;
839
840 spin_lock_irqsave(&target_list_lock, flags);
841 list_for_each_entry(nt, &target_list, list)
842 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
843 send_ext_msg_udp(nt, msg, len);
844 spin_unlock_irqrestore(&target_list_lock, flags);
845}
846
847static void write_msg(struct console *con, const char *msg, unsigned int len)
848{
849 int frag, left;
850 unsigned long flags;
851 struct netconsole_target *nt;
852 const char *tmp;
853
854 if (oops_only && !oops_in_progress)
855 return;
856 /* Avoid taking lock and disabling interrupts unnecessarily */
857 if (list_empty(&target_list))
858 return;
859
860 spin_lock_irqsave(&target_list_lock, flags);
861 list_for_each_entry(nt, &target_list, list) {
862 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
863 /*
864 * We nest this inside the for-each-target loop above
865 * so that we're able to get as much logging out to
866 * at least one target if we die inside here, instead
867 * of unnecessarily keeping all targets in lock-step.
868 */
869 tmp = msg;
870 for (left = len; left;) {
871 frag = min(left, MAX_PRINT_CHUNK);
872 netpoll_send_udp(&nt->np, tmp, frag);
873 tmp += frag;
874 left -= frag;
875 }
876 }
877 }
878 spin_unlock_irqrestore(&target_list_lock, flags);
879}
880
881static struct console netconsole_ext = {
882 .name = "netcon_ext",
883 .flags = CON_EXTENDED, /* starts disabled, registered on first use */
884 .write = write_ext_msg,
885};
886
887static struct console netconsole = {
888 .name = "netcon",
889 .flags = CON_ENABLED,
890 .write = write_msg,
891};
892
893static int __init init_netconsole(void)
894{
895 int err;
896 struct netconsole_target *nt, *tmp;
897 unsigned long flags;
898 char *target_config;
899 char *input = config;
900
901 if (strnlen(input, MAX_PARAM_LENGTH)) {
902 while ((target_config = strsep(&input, ";"))) {
903 nt = alloc_param_target(target_config);
904 if (IS_ERR(nt)) {
905 err = PTR_ERR(nt);
906 goto fail;
907 }
908 /* Dump existing printks when we register */
909 if (nt->extended)
910 netconsole_ext.flags |= CON_PRINTBUFFER |
911 CON_ENABLED;
912 else
913 netconsole.flags |= CON_PRINTBUFFER;
914
915 spin_lock_irqsave(&target_list_lock, flags);
916 list_add(&nt->list, &target_list);
917 spin_unlock_irqrestore(&target_list_lock, flags);
918 }
919 }
920
921 err = register_netdevice_notifier(&netconsole_netdev_notifier);
922 if (err)
923 goto fail;
924
925 err = dynamic_netconsole_init();
926 if (err)
927 goto undonotifier;
928
929 if (netconsole_ext.flags & CON_ENABLED)
930 register_console(&netconsole_ext);
931 register_console(&netconsole);
932 pr_info("network logging started\n");
933
934 return err;
935
936undonotifier:
937 unregister_netdevice_notifier(&netconsole_netdev_notifier);
938
939fail:
940 pr_err("cleaning up\n");
941
942 /*
943 * Remove all targets and destroy them (only targets created
944 * from the boot/module option exist here). Skipping the list
945 * lock is safe here, and netpoll_cleanup() will sleep.
946 */
947 list_for_each_entry_safe(nt, tmp, &target_list, list) {
948 list_del(&nt->list);
949 free_param_target(nt);
950 }
951
952 return err;
953}
954
955static void __exit cleanup_netconsole(void)
956{
957 struct netconsole_target *nt, *tmp;
958
959 unregister_console(&netconsole_ext);
960 unregister_console(&netconsole);
961 dynamic_netconsole_exit();
962 unregister_netdevice_notifier(&netconsole_netdev_notifier);
963
964 /*
965 * Targets created via configfs pin references on our module
966 * and would first be rmdir(2)'ed from userspace. We reach
967 * here only when they are already destroyed, and only those
968 * created from the boot/module option are left, so remove and
969 * destroy them. Skipping the list lock is safe here, and
970 * netpoll_cleanup() will sleep.
971 */
972 list_for_each_entry_safe(nt, tmp, &target_list, list) {
973 list_del(&nt->list);
974 free_param_target(nt);
975 }
976}
977
978/*
979 * Use late_initcall to ensure netconsole is
980 * initialized after network device driver if built-in.
981 *
982 * late_initcall() and module_init() are identical if built as module.
983 */
984late_initcall(init_netconsole);
985module_exit(cleanup_netconsole);
986