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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#include <linux/utsname.h>
40#include <linux/rtnetlink.h>
41
42MODULE_AUTHOR("Matt Mackall <mpm@selenic.com>");
43MODULE_DESCRIPTION("Console driver for network interfaces");
44MODULE_LICENSE("GPL");
45
46#define MAX_PARAM_LENGTH 256
47#define MAX_USERDATA_ENTRY_LENGTH 256
48#define MAX_USERDATA_VALUE_LENGTH 200
49/* The number 3 comes from userdata entry format characters (' ', '=', '\n') */
50#define MAX_USERDATA_NAME_LENGTH (MAX_USERDATA_ENTRY_LENGTH - \
51 MAX_USERDATA_VALUE_LENGTH - 3)
52#define MAX_USERDATA_ITEMS 16
53#define MAX_PRINT_CHUNK 1000
54
55static char config[MAX_PARAM_LENGTH];
56module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
57MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
58
59static bool oops_only;
60module_param(oops_only, bool, 0600);
61MODULE_PARM_DESC(oops_only, "Only log oops messages");
62
63#define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline"
64
65#ifndef MODULE
66static int __init option_setup(char *opt)
67{
68 strscpy(config, opt, MAX_PARAM_LENGTH);
69 return 1;
70}
71__setup("netconsole=", option_setup);
72#endif /* MODULE */
73
74/* Linked list of all configured targets */
75static LIST_HEAD(target_list);
76/* target_cleanup_list is used to track targets that need to be cleaned outside
77 * of target_list_lock. It should be cleaned in the same function it is
78 * populated.
79 */
80static LIST_HEAD(target_cleanup_list);
81
82/* This needs to be a spinlock because write_msg() cannot sleep */
83static DEFINE_SPINLOCK(target_list_lock);
84/* This needs to be a mutex because netpoll_cleanup might sleep */
85static DEFINE_MUTEX(target_cleanup_list_lock);
86
87/*
88 * Console driver for extended netconsoles. Registered on the first use to
89 * avoid unnecessarily enabling ext message formatting.
90 */
91static struct console netconsole_ext;
92
93/**
94 * struct netconsole_target - Represents a configured netconsole target.
95 * @list: Links this target into the target_list.
96 * @group: Links us into the configfs subsystem hierarchy.
97 * @userdata_group: Links to the userdata configfs hierarchy
98 * @userdata_complete: Cached, formatted string of append
99 * @userdata_length: String length of userdata_complete
100 * @enabled: On / off knob to enable / disable target.
101 * Visible from userspace (read-write).
102 * We maintain a strict 1:1 correspondence between this and
103 * whether the corresponding netpoll is active or inactive.
104 * Also, other parameters of a target may be modified at
105 * runtime only when it is disabled (enabled == 0).
106 * @extended: Denotes whether console is extended or not.
107 * @release: Denotes whether kernel release version should be prepended
108 * to the message. Depends on extended console.
109 * @np: The netpoll structure for this target.
110 * Contains the other userspace visible parameters:
111 * dev_name (read-write)
112 * local_port (read-write)
113 * remote_port (read-write)
114 * local_ip (read-write)
115 * remote_ip (read-write)
116 * local_mac (read-only)
117 * remote_mac (read-write)
118 */
119struct netconsole_target {
120 struct list_head list;
121#ifdef CONFIG_NETCONSOLE_DYNAMIC
122 struct config_group group;
123 struct config_group userdata_group;
124 char userdata_complete[MAX_USERDATA_ENTRY_LENGTH * MAX_USERDATA_ITEMS];
125 size_t userdata_length;
126#endif
127 bool enabled;
128 bool extended;
129 bool release;
130 struct netpoll np;
131};
132
133#ifdef CONFIG_NETCONSOLE_DYNAMIC
134
135static struct configfs_subsystem netconsole_subsys;
136static DEFINE_MUTEX(dynamic_netconsole_mutex);
137
138static int __init dynamic_netconsole_init(void)
139{
140 config_group_init(&netconsole_subsys.su_group);
141 mutex_init(&netconsole_subsys.su_mutex);
142 return configfs_register_subsystem(&netconsole_subsys);
143}
144
145static void __exit dynamic_netconsole_exit(void)
146{
147 configfs_unregister_subsystem(&netconsole_subsys);
148}
149
150/*
151 * Targets that were created by parsing the boot/module option string
152 * do not exist in the configfs hierarchy (and have NULL names) and will
153 * never go away, so make these a no-op for them.
154 */
155static void netconsole_target_get(struct netconsole_target *nt)
156{
157 if (config_item_name(&nt->group.cg_item))
158 config_group_get(&nt->group);
159}
160
161static void netconsole_target_put(struct netconsole_target *nt)
162{
163 if (config_item_name(&nt->group.cg_item))
164 config_group_put(&nt->group);
165}
166
167#else /* !CONFIG_NETCONSOLE_DYNAMIC */
168
169static int __init dynamic_netconsole_init(void)
170{
171 return 0;
172}
173
174static void __exit dynamic_netconsole_exit(void)
175{
176}
177
178/*
179 * No danger of targets going away from under us when dynamic
180 * reconfigurability is off.
181 */
182static void netconsole_target_get(struct netconsole_target *nt)
183{
184}
185
186static void netconsole_target_put(struct netconsole_target *nt)
187{
188}
189
190static void populate_configfs_item(struct netconsole_target *nt,
191 int cmdline_count)
192{
193}
194#endif /* CONFIG_NETCONSOLE_DYNAMIC */
195
196/* Allocate and initialize with defaults.
197 * Note that these targets get their config_item fields zeroed-out.
198 */
199static struct netconsole_target *alloc_and_init(void)
200{
201 struct netconsole_target *nt;
202
203 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
204 if (!nt)
205 return nt;
206
207 if (IS_ENABLED(CONFIG_NETCONSOLE_EXTENDED_LOG))
208 nt->extended = true;
209 if (IS_ENABLED(CONFIG_NETCONSOLE_PREPEND_RELEASE))
210 nt->release = true;
211
212 nt->np.name = "netconsole";
213 strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
214 nt->np.local_port = 6665;
215 nt->np.remote_port = 6666;
216 eth_broadcast_addr(nt->np.remote_mac);
217
218 return nt;
219}
220
221/* Clean up every target in the cleanup_list and move the clean targets back to
222 * the main target_list.
223 */
224static void netconsole_process_cleanups_core(void)
225{
226 struct netconsole_target *nt, *tmp;
227 unsigned long flags;
228
229 /* The cleanup needs RTNL locked */
230 ASSERT_RTNL();
231
232 mutex_lock(&target_cleanup_list_lock);
233 list_for_each_entry_safe(nt, tmp, &target_cleanup_list, list) {
234 /* all entries in the cleanup_list needs to be disabled */
235 WARN_ON_ONCE(nt->enabled);
236 do_netpoll_cleanup(&nt->np);
237 /* moved the cleaned target to target_list. Need to hold both
238 * locks
239 */
240 spin_lock_irqsave(&target_list_lock, flags);
241 list_move(&nt->list, &target_list);
242 spin_unlock_irqrestore(&target_list_lock, flags);
243 }
244 WARN_ON_ONCE(!list_empty(&target_cleanup_list));
245 mutex_unlock(&target_cleanup_list_lock);
246}
247
248#ifdef CONFIG_NETCONSOLE_DYNAMIC
249
250/*
251 * Our subsystem hierarchy is:
252 *
253 * /sys/kernel/config/netconsole/
254 * |
255 * <target>/
256 * | enabled
257 * | release
258 * | dev_name
259 * | local_port
260 * | remote_port
261 * | local_ip
262 * | remote_ip
263 * | local_mac
264 * | remote_mac
265 * | userdata/
266 * | <key>/
267 * | value
268 * | ...
269 * |
270 * <target>/...
271 */
272
273static struct netconsole_target *to_target(struct config_item *item)
274{
275 struct config_group *cfg_group;
276
277 cfg_group = to_config_group(item);
278 if (!cfg_group)
279 return NULL;
280 return container_of(to_config_group(item),
281 struct netconsole_target, group);
282}
283
284/* Do the list cleanup with the rtnl lock hold. rtnl lock is necessary because
285 * netdev might be cleaned-up by calling __netpoll_cleanup(),
286 */
287static void netconsole_process_cleanups(void)
288{
289 /* rtnl lock is called here, because it has precedence over
290 * target_cleanup_list_lock mutex and target_cleanup_list
291 */
292 rtnl_lock();
293 netconsole_process_cleanups_core();
294 rtnl_unlock();
295}
296
297/* Get rid of possible trailing newline, returning the new length */
298static void trim_newline(char *s, size_t maxlen)
299{
300 size_t len;
301
302 len = strnlen(s, maxlen);
303 if (s[len - 1] == '\n')
304 s[len - 1] = '\0';
305}
306
307/*
308 * Attribute operations for netconsole_target.
309 */
310
311static ssize_t enabled_show(struct config_item *item, char *buf)
312{
313 return sysfs_emit(buf, "%d\n", to_target(item)->enabled);
314}
315
316static ssize_t extended_show(struct config_item *item, char *buf)
317{
318 return sysfs_emit(buf, "%d\n", to_target(item)->extended);
319}
320
321static ssize_t release_show(struct config_item *item, char *buf)
322{
323 return sysfs_emit(buf, "%d\n", to_target(item)->release);
324}
325
326static ssize_t dev_name_show(struct config_item *item, char *buf)
327{
328 return sysfs_emit(buf, "%s\n", to_target(item)->np.dev_name);
329}
330
331static ssize_t local_port_show(struct config_item *item, char *buf)
332{
333 return sysfs_emit(buf, "%d\n", to_target(item)->np.local_port);
334}
335
336static ssize_t remote_port_show(struct config_item *item, char *buf)
337{
338 return sysfs_emit(buf, "%d\n", to_target(item)->np.remote_port);
339}
340
341static ssize_t local_ip_show(struct config_item *item, char *buf)
342{
343 struct netconsole_target *nt = to_target(item);
344
345 if (nt->np.ipv6)
346 return sysfs_emit(buf, "%pI6c\n", &nt->np.local_ip.in6);
347 else
348 return sysfs_emit(buf, "%pI4\n", &nt->np.local_ip);
349}
350
351static ssize_t remote_ip_show(struct config_item *item, char *buf)
352{
353 struct netconsole_target *nt = to_target(item);
354
355 if (nt->np.ipv6)
356 return sysfs_emit(buf, "%pI6c\n", &nt->np.remote_ip.in6);
357 else
358 return sysfs_emit(buf, "%pI4\n", &nt->np.remote_ip);
359}
360
361static ssize_t local_mac_show(struct config_item *item, char *buf)
362{
363 struct net_device *dev = to_target(item)->np.dev;
364 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
365
366 return sysfs_emit(buf, "%pM\n", dev ? dev->dev_addr : bcast);
367}
368
369static ssize_t remote_mac_show(struct config_item *item, char *buf)
370{
371 return sysfs_emit(buf, "%pM\n", to_target(item)->np.remote_mac);
372}
373
374/*
375 * This one is special -- targets created through the configfs interface
376 * are not enabled (and the corresponding netpoll activated) by default.
377 * The user is expected to set the desired parameters first (which
378 * would enable him to dynamically add new netpoll targets for new
379 * network interfaces as and when they come up).
380 */
381static ssize_t enabled_store(struct config_item *item,
382 const char *buf, size_t count)
383{
384 struct netconsole_target *nt = to_target(item);
385 unsigned long flags;
386 bool enabled;
387 ssize_t ret;
388
389 mutex_lock(&dynamic_netconsole_mutex);
390 ret = kstrtobool(buf, &enabled);
391 if (ret)
392 goto out_unlock;
393
394 ret = -EINVAL;
395 if (enabled == nt->enabled) {
396 pr_info("network logging has already %s\n",
397 nt->enabled ? "started" : "stopped");
398 goto out_unlock;
399 }
400
401 if (enabled) { /* true */
402 if (nt->release && !nt->extended) {
403 pr_err("Not enabling netconsole. Release feature requires extended log message");
404 goto out_unlock;
405 }
406
407 if (nt->extended && !console_is_registered(&netconsole_ext))
408 register_console(&netconsole_ext);
409
410 /*
411 * Skip netpoll_parse_options() -- all the attributes are
412 * already configured via configfs. Just print them out.
413 */
414 netpoll_print_options(&nt->np);
415
416 ret = netpoll_setup(&nt->np);
417 if (ret)
418 goto out_unlock;
419
420 nt->enabled = true;
421 pr_info("network logging started\n");
422 } else { /* false */
423 /* We need to disable the netconsole before cleaning it up
424 * otherwise we might end up in write_msg() with
425 * nt->np.dev == NULL and nt->enabled == true
426 */
427 mutex_lock(&target_cleanup_list_lock);
428 spin_lock_irqsave(&target_list_lock, flags);
429 nt->enabled = false;
430 /* Remove the target from the list, while holding
431 * target_list_lock
432 */
433 list_move(&nt->list, &target_cleanup_list);
434 spin_unlock_irqrestore(&target_list_lock, flags);
435 mutex_unlock(&target_cleanup_list_lock);
436 }
437
438 ret = strnlen(buf, count);
439 /* Deferred cleanup */
440 netconsole_process_cleanups();
441out_unlock:
442 mutex_unlock(&dynamic_netconsole_mutex);
443 return ret;
444}
445
446static ssize_t release_store(struct config_item *item, const char *buf,
447 size_t count)
448{
449 struct netconsole_target *nt = to_target(item);
450 bool release;
451 ssize_t ret;
452
453 mutex_lock(&dynamic_netconsole_mutex);
454 if (nt->enabled) {
455 pr_err("target (%s) is enabled, disable to update parameters\n",
456 config_item_name(&nt->group.cg_item));
457 ret = -EINVAL;
458 goto out_unlock;
459 }
460
461 ret = kstrtobool(buf, &release);
462 if (ret)
463 goto out_unlock;
464
465 nt->release = release;
466
467 ret = strnlen(buf, count);
468out_unlock:
469 mutex_unlock(&dynamic_netconsole_mutex);
470 return ret;
471}
472
473static ssize_t extended_store(struct config_item *item, const char *buf,
474 size_t count)
475{
476 struct netconsole_target *nt = to_target(item);
477 bool extended;
478 ssize_t ret;
479
480 mutex_lock(&dynamic_netconsole_mutex);
481 if (nt->enabled) {
482 pr_err("target (%s) is enabled, disable to update parameters\n",
483 config_item_name(&nt->group.cg_item));
484 ret = -EINVAL;
485 goto out_unlock;
486 }
487
488 ret = kstrtobool(buf, &extended);
489 if (ret)
490 goto out_unlock;
491
492 nt->extended = extended;
493 ret = strnlen(buf, count);
494out_unlock:
495 mutex_unlock(&dynamic_netconsole_mutex);
496 return ret;
497}
498
499static ssize_t dev_name_store(struct config_item *item, const char *buf,
500 size_t count)
501{
502 struct netconsole_target *nt = to_target(item);
503
504 mutex_lock(&dynamic_netconsole_mutex);
505 if (nt->enabled) {
506 pr_err("target (%s) is enabled, disable to update parameters\n",
507 config_item_name(&nt->group.cg_item));
508 mutex_unlock(&dynamic_netconsole_mutex);
509 return -EINVAL;
510 }
511
512 strscpy(nt->np.dev_name, buf, IFNAMSIZ);
513 trim_newline(nt->np.dev_name, IFNAMSIZ);
514
515 mutex_unlock(&dynamic_netconsole_mutex);
516 return strnlen(buf, count);
517}
518
519static ssize_t local_port_store(struct config_item *item, const char *buf,
520 size_t count)
521{
522 struct netconsole_target *nt = to_target(item);
523 ssize_t ret = -EINVAL;
524
525 mutex_lock(&dynamic_netconsole_mutex);
526 if (nt->enabled) {
527 pr_err("target (%s) is enabled, disable to update parameters\n",
528 config_item_name(&nt->group.cg_item));
529 goto out_unlock;
530 }
531
532 ret = kstrtou16(buf, 10, &nt->np.local_port);
533 if (ret < 0)
534 goto out_unlock;
535 ret = strnlen(buf, count);
536out_unlock:
537 mutex_unlock(&dynamic_netconsole_mutex);
538 return ret;
539}
540
541static ssize_t remote_port_store(struct config_item *item,
542 const char *buf, size_t count)
543{
544 struct netconsole_target *nt = to_target(item);
545 ssize_t ret = -EINVAL;
546
547 mutex_lock(&dynamic_netconsole_mutex);
548 if (nt->enabled) {
549 pr_err("target (%s) is enabled, disable to update parameters\n",
550 config_item_name(&nt->group.cg_item));
551 goto out_unlock;
552 }
553
554 ret = kstrtou16(buf, 10, &nt->np.remote_port);
555 if (ret < 0)
556 goto out_unlock;
557 ret = strnlen(buf, count);
558out_unlock:
559 mutex_unlock(&dynamic_netconsole_mutex);
560 return ret;
561}
562
563static ssize_t local_ip_store(struct config_item *item, const char *buf,
564 size_t count)
565{
566 struct netconsole_target *nt = to_target(item);
567 ssize_t ret = -EINVAL;
568
569 mutex_lock(&dynamic_netconsole_mutex);
570 if (nt->enabled) {
571 pr_err("target (%s) is enabled, disable to update parameters\n",
572 config_item_name(&nt->group.cg_item));
573 goto out_unlock;
574 }
575
576 if (strnchr(buf, count, ':')) {
577 const char *end;
578
579 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
580 if (*end && *end != '\n') {
581 pr_err("invalid IPv6 address at: <%c>\n", *end);
582 goto out_unlock;
583 }
584 nt->np.ipv6 = true;
585 } else
586 goto out_unlock;
587 } else {
588 if (!nt->np.ipv6)
589 nt->np.local_ip.ip = in_aton(buf);
590 else
591 goto out_unlock;
592 }
593
594 ret = strnlen(buf, count);
595out_unlock:
596 mutex_unlock(&dynamic_netconsole_mutex);
597 return ret;
598}
599
600static ssize_t remote_ip_store(struct config_item *item, const char *buf,
601 size_t count)
602{
603 struct netconsole_target *nt = to_target(item);
604 ssize_t ret = -EINVAL;
605
606 mutex_lock(&dynamic_netconsole_mutex);
607 if (nt->enabled) {
608 pr_err("target (%s) is enabled, disable to update parameters\n",
609 config_item_name(&nt->group.cg_item));
610 goto out_unlock;
611 }
612
613 if (strnchr(buf, count, ':')) {
614 const char *end;
615
616 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
617 if (*end && *end != '\n') {
618 pr_err("invalid IPv6 address at: <%c>\n", *end);
619 goto out_unlock;
620 }
621 nt->np.ipv6 = true;
622 } else
623 goto out_unlock;
624 } else {
625 if (!nt->np.ipv6)
626 nt->np.remote_ip.ip = in_aton(buf);
627 else
628 goto out_unlock;
629 }
630
631 ret = strnlen(buf, count);
632out_unlock:
633 mutex_unlock(&dynamic_netconsole_mutex);
634 return ret;
635}
636
637static ssize_t remote_mac_store(struct config_item *item, const char *buf,
638 size_t count)
639{
640 struct netconsole_target *nt = to_target(item);
641 u8 remote_mac[ETH_ALEN];
642 ssize_t ret = -EINVAL;
643
644 mutex_lock(&dynamic_netconsole_mutex);
645 if (nt->enabled) {
646 pr_err("target (%s) is enabled, disable to update parameters\n",
647 config_item_name(&nt->group.cg_item));
648 goto out_unlock;
649 }
650
651 if (!mac_pton(buf, remote_mac))
652 goto out_unlock;
653 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
654 goto out_unlock;
655 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
656
657 ret = strnlen(buf, count);
658out_unlock:
659 mutex_unlock(&dynamic_netconsole_mutex);
660 return ret;
661}
662
663struct userdatum {
664 struct config_item item;
665 char value[MAX_USERDATA_VALUE_LENGTH];
666};
667
668static struct userdatum *to_userdatum(struct config_item *item)
669{
670 return container_of(item, struct userdatum, item);
671}
672
673struct userdata {
674 struct config_group group;
675};
676
677static struct userdata *to_userdata(struct config_item *item)
678{
679 return container_of(to_config_group(item), struct userdata, group);
680}
681
682static struct netconsole_target *userdata_to_target(struct userdata *ud)
683{
684 struct config_group *netconsole_group;
685
686 netconsole_group = to_config_group(ud->group.cg_item.ci_parent);
687 return to_target(&netconsole_group->cg_item);
688}
689
690static ssize_t userdatum_value_show(struct config_item *item, char *buf)
691{
692 return sysfs_emit(buf, "%s\n", &(to_userdatum(item)->value[0]));
693}
694
695static void update_userdata(struct netconsole_target *nt)
696{
697 int complete_idx = 0, child_count = 0;
698 struct list_head *entry;
699
700 /* Clear the current string in case the last userdatum was deleted */
701 nt->userdata_length = 0;
702 nt->userdata_complete[0] = 0;
703
704 list_for_each(entry, &nt->userdata_group.cg_children) {
705 struct userdatum *udm_item;
706 struct config_item *item;
707
708 if (child_count >= MAX_USERDATA_ITEMS)
709 break;
710 child_count++;
711
712 item = container_of(entry, struct config_item, ci_entry);
713 udm_item = to_userdatum(item);
714
715 /* Skip userdata with no value set */
716 if (strnlen(udm_item->value, MAX_USERDATA_VALUE_LENGTH) == 0)
717 continue;
718
719 /* This doesn't overflow userdata_complete since it will write
720 * one entry length (1/MAX_USERDATA_ITEMS long), entry count is
721 * checked to not exceed MAX items with child_count above
722 */
723 complete_idx += scnprintf(&nt->userdata_complete[complete_idx],
724 MAX_USERDATA_ENTRY_LENGTH, " %s=%s\n",
725 item->ci_name, udm_item->value);
726 }
727 nt->userdata_length = strnlen(nt->userdata_complete,
728 sizeof(nt->userdata_complete));
729}
730
731static ssize_t userdatum_value_store(struct config_item *item, const char *buf,
732 size_t count)
733{
734 struct userdatum *udm = to_userdatum(item);
735 struct netconsole_target *nt;
736 struct userdata *ud;
737 ssize_t ret;
738
739 if (count > MAX_USERDATA_VALUE_LENGTH)
740 return -EMSGSIZE;
741
742 mutex_lock(&dynamic_netconsole_mutex);
743
744 ret = strscpy(udm->value, buf, sizeof(udm->value));
745 if (ret < 0)
746 goto out_unlock;
747 trim_newline(udm->value, sizeof(udm->value));
748
749 ud = to_userdata(item->ci_parent);
750 nt = userdata_to_target(ud);
751 update_userdata(nt);
752 ret = count;
753out_unlock:
754 mutex_unlock(&dynamic_netconsole_mutex);
755 return ret;
756}
757
758CONFIGFS_ATTR(userdatum_, value);
759
760static struct configfs_attribute *userdatum_attrs[] = {
761 &userdatum_attr_value,
762 NULL,
763};
764
765static void userdatum_release(struct config_item *item)
766{
767 kfree(to_userdatum(item));
768}
769
770static struct configfs_item_operations userdatum_ops = {
771 .release = userdatum_release,
772};
773
774static const struct config_item_type userdatum_type = {
775 .ct_item_ops = &userdatum_ops,
776 .ct_attrs = userdatum_attrs,
777 .ct_owner = THIS_MODULE,
778};
779
780static struct config_item *userdatum_make_item(struct config_group *group,
781 const char *name)
782{
783 struct netconsole_target *nt;
784 struct userdatum *udm;
785 struct userdata *ud;
786 size_t child_count;
787
788 if (strlen(name) > MAX_USERDATA_NAME_LENGTH)
789 return ERR_PTR(-ENAMETOOLONG);
790
791 ud = to_userdata(&group->cg_item);
792 nt = userdata_to_target(ud);
793 child_count = list_count_nodes(&nt->userdata_group.cg_children);
794 if (child_count >= MAX_USERDATA_ITEMS)
795 return ERR_PTR(-ENOSPC);
796
797 udm = kzalloc(sizeof(*udm), GFP_KERNEL);
798 if (!udm)
799 return ERR_PTR(-ENOMEM);
800
801 config_item_init_type_name(&udm->item, name, &userdatum_type);
802 return &udm->item;
803}
804
805static void userdatum_drop(struct config_group *group, struct config_item *item)
806{
807 struct netconsole_target *nt;
808 struct userdata *ud;
809
810 ud = to_userdata(&group->cg_item);
811 nt = userdata_to_target(ud);
812
813 mutex_lock(&dynamic_netconsole_mutex);
814 update_userdata(nt);
815 config_item_put(item);
816 mutex_unlock(&dynamic_netconsole_mutex);
817}
818
819static struct configfs_attribute *userdata_attrs[] = {
820 NULL,
821};
822
823static struct configfs_group_operations userdata_ops = {
824 .make_item = userdatum_make_item,
825 .drop_item = userdatum_drop,
826};
827
828static const struct config_item_type userdata_type = {
829 .ct_item_ops = &userdatum_ops,
830 .ct_group_ops = &userdata_ops,
831 .ct_attrs = userdata_attrs,
832 .ct_owner = THIS_MODULE,
833};
834
835CONFIGFS_ATTR(, enabled);
836CONFIGFS_ATTR(, extended);
837CONFIGFS_ATTR(, dev_name);
838CONFIGFS_ATTR(, local_port);
839CONFIGFS_ATTR(, remote_port);
840CONFIGFS_ATTR(, local_ip);
841CONFIGFS_ATTR(, remote_ip);
842CONFIGFS_ATTR_RO(, local_mac);
843CONFIGFS_ATTR(, remote_mac);
844CONFIGFS_ATTR(, release);
845
846static struct configfs_attribute *netconsole_target_attrs[] = {
847 &attr_enabled,
848 &attr_extended,
849 &attr_release,
850 &attr_dev_name,
851 &attr_local_port,
852 &attr_remote_port,
853 &attr_local_ip,
854 &attr_remote_ip,
855 &attr_local_mac,
856 &attr_remote_mac,
857 NULL,
858};
859
860/*
861 * Item operations and type for netconsole_target.
862 */
863
864static void netconsole_target_release(struct config_item *item)
865{
866 kfree(to_target(item));
867}
868
869static struct configfs_item_operations netconsole_target_item_ops = {
870 .release = netconsole_target_release,
871};
872
873static const struct config_item_type netconsole_target_type = {
874 .ct_attrs = netconsole_target_attrs,
875 .ct_item_ops = &netconsole_target_item_ops,
876 .ct_owner = THIS_MODULE,
877};
878
879static void init_target_config_group(struct netconsole_target *nt,
880 const char *name)
881{
882 config_group_init_type_name(&nt->group, name, &netconsole_target_type);
883 config_group_init_type_name(&nt->userdata_group, "userdata",
884 &userdata_type);
885 configfs_add_default_group(&nt->userdata_group, &nt->group);
886}
887
888static struct netconsole_target *find_cmdline_target(const char *name)
889{
890 struct netconsole_target *nt, *ret = NULL;
891 unsigned long flags;
892
893 spin_lock_irqsave(&target_list_lock, flags);
894 list_for_each_entry(nt, &target_list, list) {
895 if (!strcmp(nt->group.cg_item.ci_name, name)) {
896 ret = nt;
897 break;
898 }
899 }
900 spin_unlock_irqrestore(&target_list_lock, flags);
901
902 return ret;
903}
904
905/*
906 * Group operations and type for netconsole_subsys.
907 */
908
909static struct config_group *make_netconsole_target(struct config_group *group,
910 const char *name)
911{
912 struct netconsole_target *nt;
913 unsigned long flags;
914
915 /* Checking if a target by this name was created at boot time. If so,
916 * attach a configfs entry to that target. This enables dynamic
917 * control.
918 */
919 if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX,
920 strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
921 nt = find_cmdline_target(name);
922 if (nt) {
923 init_target_config_group(nt, name);
924 return &nt->group;
925 }
926 }
927
928 nt = alloc_and_init();
929 if (!nt)
930 return ERR_PTR(-ENOMEM);
931
932 /* Initialize the config_group member */
933 init_target_config_group(nt, name);
934
935 /* Adding, but it is disabled */
936 spin_lock_irqsave(&target_list_lock, flags);
937 list_add(&nt->list, &target_list);
938 spin_unlock_irqrestore(&target_list_lock, flags);
939
940 return &nt->group;
941}
942
943static void drop_netconsole_target(struct config_group *group,
944 struct config_item *item)
945{
946 unsigned long flags;
947 struct netconsole_target *nt = to_target(item);
948
949 spin_lock_irqsave(&target_list_lock, flags);
950 list_del(&nt->list);
951 spin_unlock_irqrestore(&target_list_lock, flags);
952
953 /*
954 * The target may have never been enabled, or was manually disabled
955 * before being removed so netpoll may have already been cleaned up.
956 */
957 if (nt->enabled)
958 netpoll_cleanup(&nt->np);
959
960 config_item_put(&nt->group.cg_item);
961}
962
963static struct configfs_group_operations netconsole_subsys_group_ops = {
964 .make_group = make_netconsole_target,
965 .drop_item = drop_netconsole_target,
966};
967
968static const struct config_item_type netconsole_subsys_type = {
969 .ct_group_ops = &netconsole_subsys_group_ops,
970 .ct_owner = THIS_MODULE,
971};
972
973/* The netconsole configfs subsystem */
974static struct configfs_subsystem netconsole_subsys = {
975 .su_group = {
976 .cg_item = {
977 .ci_namebuf = "netconsole",
978 .ci_type = &netconsole_subsys_type,
979 },
980 },
981};
982
983static void populate_configfs_item(struct netconsole_target *nt,
984 int cmdline_count)
985{
986 char target_name[16];
987
988 snprintf(target_name, sizeof(target_name), "%s%d",
989 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
990 init_target_config_group(nt, target_name);
991}
992
993#endif /* CONFIG_NETCONSOLE_DYNAMIC */
994
995/* Handle network interface device notifications */
996static int netconsole_netdev_event(struct notifier_block *this,
997 unsigned long event, void *ptr)
998{
999 unsigned long flags;
1000 struct netconsole_target *nt, *tmp;
1001 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1002 bool stopped = false;
1003
1004 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
1005 event == NETDEV_RELEASE || event == NETDEV_JOIN))
1006 goto done;
1007
1008 mutex_lock(&target_cleanup_list_lock);
1009 spin_lock_irqsave(&target_list_lock, flags);
1010 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1011 netconsole_target_get(nt);
1012 if (nt->np.dev == dev) {
1013 switch (event) {
1014 case NETDEV_CHANGENAME:
1015 strscpy(nt->np.dev_name, dev->name, IFNAMSIZ);
1016 break;
1017 case NETDEV_RELEASE:
1018 case NETDEV_JOIN:
1019 case NETDEV_UNREGISTER:
1020 nt->enabled = false;
1021 list_move(&nt->list, &target_cleanup_list);
1022 stopped = true;
1023 }
1024 }
1025 netconsole_target_put(nt);
1026 }
1027 spin_unlock_irqrestore(&target_list_lock, flags);
1028 mutex_unlock(&target_cleanup_list_lock);
1029
1030 if (stopped) {
1031 const char *msg = "had an event";
1032
1033 switch (event) {
1034 case NETDEV_UNREGISTER:
1035 msg = "unregistered";
1036 break;
1037 case NETDEV_RELEASE:
1038 msg = "released slaves";
1039 break;
1040 case NETDEV_JOIN:
1041 msg = "is joining a master device";
1042 break;
1043 }
1044 pr_info("network logging stopped on interface %s as it %s\n",
1045 dev->name, msg);
1046 }
1047
1048 /* Process target_cleanup_list entries. By the end, target_cleanup_list
1049 * should be empty
1050 */
1051 netconsole_process_cleanups_core();
1052
1053done:
1054 return NOTIFY_DONE;
1055}
1056
1057static struct notifier_block netconsole_netdev_notifier = {
1058 .notifier_call = netconsole_netdev_event,
1059};
1060
1061static void send_msg_no_fragmentation(struct netconsole_target *nt,
1062 const char *msg,
1063 int msg_len,
1064 int release_len)
1065{
1066 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
1067 const char *userdata = NULL;
1068 const char *release;
1069
1070#ifdef CONFIG_NETCONSOLE_DYNAMIC
1071 userdata = nt->userdata_complete;
1072#endif
1073
1074 if (release_len) {
1075 release = init_utsname()->release;
1076
1077 scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg);
1078 msg_len += release_len;
1079 } else {
1080 memcpy(buf, msg, msg_len);
1081 }
1082
1083 if (userdata)
1084 msg_len += scnprintf(&buf[msg_len],
1085 MAX_PRINT_CHUNK - msg_len,
1086 "%s", userdata);
1087
1088 netpoll_send_udp(&nt->np, buf, msg_len);
1089}
1090
1091static void append_release(char *buf)
1092{
1093 const char *release;
1094
1095 release = init_utsname()->release;
1096 scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
1097}
1098
1099static void send_fragmented_body(struct netconsole_target *nt, char *buf,
1100 const char *msgbody, int header_len,
1101 int msgbody_len)
1102{
1103 const char *userdata = NULL;
1104 int body_len, offset = 0;
1105 int userdata_len = 0;
1106
1107#ifdef CONFIG_NETCONSOLE_DYNAMIC
1108 userdata = nt->userdata_complete;
1109 userdata_len = nt->userdata_length;
1110#endif
1111
1112 /* body_len represents the number of bytes that will be sent. This is
1113 * bigger than MAX_PRINT_CHUNK, thus, it will be split in multiple
1114 * packets
1115 */
1116 body_len = msgbody_len + userdata_len;
1117
1118 /* In each iteration of the while loop below, we send a packet
1119 * containing the header and a portion of the body. The body is
1120 * composed of two parts: msgbody and userdata. We keep track of how
1121 * many bytes have been sent so far using the offset variable, which
1122 * ranges from 0 to the total length of the body.
1123 */
1124 while (offset < body_len) {
1125 int this_header = header_len;
1126 bool msgbody_written = false;
1127 int this_offset = 0;
1128 int this_chunk = 0;
1129
1130 this_header += scnprintf(buf + this_header,
1131 MAX_PRINT_CHUNK - this_header,
1132 ",ncfrag=%d/%d;", offset,
1133 body_len);
1134
1135 /* Not all msgbody data has been written yet */
1136 if (offset < msgbody_len) {
1137 this_chunk = min(msgbody_len - offset,
1138 MAX_PRINT_CHUNK - this_header);
1139 if (WARN_ON_ONCE(this_chunk <= 0))
1140 return;
1141 memcpy(buf + this_header, msgbody + offset, this_chunk);
1142 this_offset += this_chunk;
1143 }
1144
1145 /* msgbody was finally written, either in the previous
1146 * messages and/or in the current buf. Time to write
1147 * the userdata.
1148 */
1149 msgbody_written |= offset + this_offset >= msgbody_len;
1150
1151 /* Msg body is fully written and there is pending userdata to
1152 * write, append userdata in this chunk
1153 */
1154 if (msgbody_written && offset + this_offset < body_len) {
1155 /* Track how much user data was already sent. First
1156 * time here, sent_userdata is zero
1157 */
1158 int sent_userdata = (offset + this_offset) - msgbody_len;
1159 /* offset of bytes used in current buf */
1160 int preceding_bytes = this_chunk + this_header;
1161
1162 if (WARN_ON_ONCE(sent_userdata < 0))
1163 return;
1164
1165 this_chunk = min(userdata_len - sent_userdata,
1166 MAX_PRINT_CHUNK - preceding_bytes);
1167 if (WARN_ON_ONCE(this_chunk < 0))
1168 /* this_chunk could be zero if all the previous
1169 * message used all the buffer. This is not a
1170 * problem, userdata will be sent in the next
1171 * iteration
1172 */
1173 return;
1174
1175 memcpy(buf + this_header + this_offset,
1176 userdata + sent_userdata,
1177 this_chunk);
1178 this_offset += this_chunk;
1179 }
1180
1181 netpoll_send_udp(&nt->np, buf, this_header + this_offset);
1182 offset += this_offset;
1183 }
1184}
1185
1186static void send_msg_fragmented(struct netconsole_target *nt,
1187 const char *msg,
1188 int msg_len,
1189 int release_len)
1190{
1191 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
1192 int header_len, msgbody_len;
1193 const char *msgbody;
1194
1195 /* need to insert extra header fields, detect header and msgbody */
1196 msgbody = memchr(msg, ';', msg_len);
1197 if (WARN_ON_ONCE(!msgbody))
1198 return;
1199
1200 header_len = msgbody - msg;
1201 msgbody_len = msg_len - header_len - 1;
1202 msgbody++;
1203
1204 /*
1205 * Transfer multiple chunks with the following extra header.
1206 * "ncfrag=<byte-offset>/<total-bytes>"
1207 */
1208 if (release_len)
1209 append_release(buf);
1210
1211 /* Copy the header into the buffer */
1212 memcpy(buf + release_len, msg, header_len);
1213 header_len += release_len;
1214
1215 /* for now on, the header will be persisted, and the msgbody
1216 * will be replaced
1217 */
1218 send_fragmented_body(nt, buf, msgbody, header_len, msgbody_len);
1219}
1220
1221/**
1222 * send_ext_msg_udp - send extended log message to target
1223 * @nt: target to send message to
1224 * @msg: extended log message to send
1225 * @msg_len: length of message
1226 *
1227 * Transfer extended log @msg to @nt. If @msg is longer than
1228 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
1229 * ncfrag header field added to identify them.
1230 */
1231static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
1232 int msg_len)
1233{
1234 int userdata_len = 0;
1235 int release_len = 0;
1236
1237#ifdef CONFIG_NETCONSOLE_DYNAMIC
1238 userdata_len = nt->userdata_length;
1239#endif
1240
1241 if (nt->release)
1242 release_len = strlen(init_utsname()->release) + 1;
1243
1244 if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK)
1245 return send_msg_no_fragmentation(nt, msg, msg_len, release_len);
1246
1247 return send_msg_fragmented(nt, msg, msg_len, release_len);
1248}
1249
1250static void write_ext_msg(struct console *con, const char *msg,
1251 unsigned int len)
1252{
1253 struct netconsole_target *nt;
1254 unsigned long flags;
1255
1256 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
1257 return;
1258
1259 spin_lock_irqsave(&target_list_lock, flags);
1260 list_for_each_entry(nt, &target_list, list)
1261 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
1262 send_ext_msg_udp(nt, msg, len);
1263 spin_unlock_irqrestore(&target_list_lock, flags);
1264}
1265
1266static void write_msg(struct console *con, const char *msg, unsigned int len)
1267{
1268 int frag, left;
1269 unsigned long flags;
1270 struct netconsole_target *nt;
1271 const char *tmp;
1272
1273 if (oops_only && !oops_in_progress)
1274 return;
1275 /* Avoid taking lock and disabling interrupts unnecessarily */
1276 if (list_empty(&target_list))
1277 return;
1278
1279 spin_lock_irqsave(&target_list_lock, flags);
1280 list_for_each_entry(nt, &target_list, list) {
1281 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
1282 /*
1283 * We nest this inside the for-each-target loop above
1284 * so that we're able to get as much logging out to
1285 * at least one target if we die inside here, instead
1286 * of unnecessarily keeping all targets in lock-step.
1287 */
1288 tmp = msg;
1289 for (left = len; left;) {
1290 frag = min(left, MAX_PRINT_CHUNK);
1291 netpoll_send_udp(&nt->np, tmp, frag);
1292 tmp += frag;
1293 left -= frag;
1294 }
1295 }
1296 }
1297 spin_unlock_irqrestore(&target_list_lock, flags);
1298}
1299
1300/* Allocate new target (from boot/module param) and setup netpoll for it */
1301static struct netconsole_target *alloc_param_target(char *target_config,
1302 int cmdline_count)
1303{
1304 struct netconsole_target *nt;
1305 int err;
1306
1307 nt = alloc_and_init();
1308 if (!nt) {
1309 err = -ENOMEM;
1310 goto fail;
1311 }
1312
1313 if (*target_config == '+') {
1314 nt->extended = true;
1315 target_config++;
1316 }
1317
1318 if (*target_config == 'r') {
1319 if (!nt->extended) {
1320 pr_err("Netconsole configuration error. Release feature requires extended log message");
1321 err = -EINVAL;
1322 goto fail;
1323 }
1324 nt->release = true;
1325 target_config++;
1326 }
1327
1328 /* Parse parameters and setup netpoll */
1329 err = netpoll_parse_options(&nt->np, target_config);
1330 if (err)
1331 goto fail;
1332
1333 err = netpoll_setup(&nt->np);
1334 if (err) {
1335 pr_err("Not enabling netconsole for %s%d. Netpoll setup failed\n",
1336 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
1337 if (!IS_ENABLED(CONFIG_NETCONSOLE_DYNAMIC))
1338 /* only fail if dynamic reconfiguration is set,
1339 * otherwise, keep the target in the list, but disabled.
1340 */
1341 goto fail;
1342 } else {
1343 nt->enabled = true;
1344 }
1345 populate_configfs_item(nt, cmdline_count);
1346
1347 return nt;
1348
1349fail:
1350 kfree(nt);
1351 return ERR_PTR(err);
1352}
1353
1354/* Cleanup netpoll for given target (from boot/module param) and free it */
1355static void free_param_target(struct netconsole_target *nt)
1356{
1357 netpoll_cleanup(&nt->np);
1358 kfree(nt);
1359}
1360
1361static struct console netconsole_ext = {
1362 .name = "netcon_ext",
1363 .flags = CON_ENABLED | CON_EXTENDED,
1364 .write = write_ext_msg,
1365};
1366
1367static struct console netconsole = {
1368 .name = "netcon",
1369 .flags = CON_ENABLED,
1370 .write = write_msg,
1371};
1372
1373static int __init init_netconsole(void)
1374{
1375 int err;
1376 struct netconsole_target *nt, *tmp;
1377 unsigned int count = 0;
1378 bool extended = false;
1379 unsigned long flags;
1380 char *target_config;
1381 char *input = config;
1382
1383 if (strnlen(input, MAX_PARAM_LENGTH)) {
1384 while ((target_config = strsep(&input, ";"))) {
1385 nt = alloc_param_target(target_config, count);
1386 if (IS_ERR(nt)) {
1387 if (IS_ENABLED(CONFIG_NETCONSOLE_DYNAMIC))
1388 continue;
1389 err = PTR_ERR(nt);
1390 goto fail;
1391 }
1392 /* Dump existing printks when we register */
1393 if (nt->extended) {
1394 extended = true;
1395 netconsole_ext.flags |= CON_PRINTBUFFER;
1396 } else {
1397 netconsole.flags |= CON_PRINTBUFFER;
1398 }
1399
1400 spin_lock_irqsave(&target_list_lock, flags);
1401 list_add(&nt->list, &target_list);
1402 spin_unlock_irqrestore(&target_list_lock, flags);
1403 count++;
1404 }
1405 }
1406
1407 err = register_netdevice_notifier(&netconsole_netdev_notifier);
1408 if (err)
1409 goto fail;
1410
1411 err = dynamic_netconsole_init();
1412 if (err)
1413 goto undonotifier;
1414
1415 if (extended)
1416 register_console(&netconsole_ext);
1417 register_console(&netconsole);
1418 pr_info("network logging started\n");
1419
1420 return err;
1421
1422undonotifier:
1423 unregister_netdevice_notifier(&netconsole_netdev_notifier);
1424
1425fail:
1426 pr_err("cleaning up\n");
1427
1428 /*
1429 * Remove all targets and destroy them (only targets created
1430 * from the boot/module option exist here). Skipping the list
1431 * lock is safe here, and netpoll_cleanup() will sleep.
1432 */
1433 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1434 list_del(&nt->list);
1435 free_param_target(nt);
1436 }
1437
1438 return err;
1439}
1440
1441static void __exit cleanup_netconsole(void)
1442{
1443 struct netconsole_target *nt, *tmp;
1444
1445 if (console_is_registered(&netconsole_ext))
1446 unregister_console(&netconsole_ext);
1447 unregister_console(&netconsole);
1448 dynamic_netconsole_exit();
1449 unregister_netdevice_notifier(&netconsole_netdev_notifier);
1450
1451 /*
1452 * Targets created via configfs pin references on our module
1453 * and would first be rmdir(2)'ed from userspace. We reach
1454 * here only when they are already destroyed, and only those
1455 * created from the boot/module option are left, so remove and
1456 * destroy them. Skipping the list lock is safe here, and
1457 * netpoll_cleanup() will sleep.
1458 */
1459 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1460 list_del(&nt->list);
1461 free_param_target(nt);
1462 }
1463}
1464
1465/*
1466 * Use late_initcall to ensure netconsole is
1467 * initialized after network device driver if built-in.
1468 *
1469 * late_initcall() and module_init() are identical if built as module.
1470 */
1471late_initcall(init_netconsole);
1472module_exit(cleanup_netconsole);
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("netconsole: 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 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 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);