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