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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
51MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
52MODULE_DESCRIPTION("Console driver for network interfaces");
53MODULE_LICENSE("GPL");
54
55#define MAX_PARAM_LENGTH 256
56#define MAX_PRINT_CHUNK 1000
57
58static char config[MAX_PARAM_LENGTH];
59module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
60MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
61
62static bool oops_only = false;
63module_param(oops_only, bool, 0600);
64MODULE_PARM_DESC(oops_only, "Only log oops messages");
65
66#ifndef MODULE
67static int __init option_setup(char *opt)
68{
69 strlcpy(config, opt, MAX_PARAM_LENGTH);
70 return 1;
71}
72__setup("netconsole=", option_setup);
73#endif /* MODULE */
74
75/* Linked list of all configured targets */
76static LIST_HEAD(target_list);
77
78/* This needs to be a spinlock because write_msg() cannot sleep */
79static DEFINE_SPINLOCK(target_list_lock);
80
81/**
82 * struct netconsole_target - Represents a configured netconsole target.
83 * @list: Links this target into the target_list.
84 * @item: Links us into the configfs subsystem hierarchy.
85 * @enabled: On / off knob to enable / disable target.
86 * Visible from userspace (read-write).
87 * We maintain a strict 1:1 correspondence between this and
88 * whether the corresponding netpoll is active or inactive.
89 * Also, other parameters of a target may be modified at
90 * runtime only when it is disabled (enabled == 0).
91 * @np: The netpoll structure for this target.
92 * Contains the other userspace visible parameters:
93 * dev_name (read-write)
94 * local_port (read-write)
95 * remote_port (read-write)
96 * local_ip (read-write)
97 * remote_ip (read-write)
98 * local_mac (read-only)
99 * remote_mac (read-write)
100 */
101struct netconsole_target {
102 struct list_head list;
103#ifdef CONFIG_NETCONSOLE_DYNAMIC
104 struct config_item item;
105#endif
106 int enabled;
107 struct mutex mutex;
108 struct netpoll np;
109};
110
111#ifdef CONFIG_NETCONSOLE_DYNAMIC
112
113static struct configfs_subsystem netconsole_subsys;
114
115static int __init dynamic_netconsole_init(void)
116{
117 config_group_init(&netconsole_subsys.su_group);
118 mutex_init(&netconsole_subsys.su_mutex);
119 return configfs_register_subsystem(&netconsole_subsys);
120}
121
122static void __exit dynamic_netconsole_exit(void)
123{
124 configfs_unregister_subsystem(&netconsole_subsys);
125}
126
127/*
128 * Targets that were created by parsing the boot/module option string
129 * do not exist in the configfs hierarchy (and have NULL names) and will
130 * never go away, so make these a no-op for them.
131 */
132static void netconsole_target_get(struct netconsole_target *nt)
133{
134 if (config_item_name(&nt->item))
135 config_item_get(&nt->item);
136}
137
138static void netconsole_target_put(struct netconsole_target *nt)
139{
140 if (config_item_name(&nt->item))
141 config_item_put(&nt->item);
142}
143
144#else /* !CONFIG_NETCONSOLE_DYNAMIC */
145
146static int __init dynamic_netconsole_init(void)
147{
148 return 0;
149}
150
151static void __exit dynamic_netconsole_exit(void)
152{
153}
154
155/*
156 * No danger of targets going away from under us when dynamic
157 * reconfigurability is off.
158 */
159static void netconsole_target_get(struct netconsole_target *nt)
160{
161}
162
163static void netconsole_target_put(struct netconsole_target *nt)
164{
165}
166
167#endif /* CONFIG_NETCONSOLE_DYNAMIC */
168
169/* Allocate new target (from boot/module param) and setup netpoll for it */
170static struct netconsole_target *alloc_param_target(char *target_config)
171{
172 int err = -ENOMEM;
173 struct netconsole_target *nt;
174
175 /*
176 * Allocate and initialize with defaults.
177 * Note that these targets get their config_item fields zeroed-out.
178 */
179 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
180 if (!nt)
181 goto fail;
182
183 nt->np.name = "netconsole";
184 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
185 nt->np.local_port = 6665;
186 nt->np.remote_port = 6666;
187 mutex_init(&nt->mutex);
188 memset(nt->np.remote_mac, 0xff, ETH_ALEN);
189
190 /* Parse parameters and setup netpoll */
191 err = netpoll_parse_options(&nt->np, target_config);
192 if (err)
193 goto fail;
194
195 err = netpoll_setup(&nt->np);
196 if (err)
197 goto fail;
198
199 nt->enabled = 1;
200
201 return nt;
202
203fail:
204 kfree(nt);
205 return ERR_PTR(err);
206}
207
208/* Cleanup netpoll for given target (from boot/module param) and free it */
209static void free_param_target(struct netconsole_target *nt)
210{
211 netpoll_cleanup(&nt->np);
212 kfree(nt);
213}
214
215#ifdef CONFIG_NETCONSOLE_DYNAMIC
216
217/*
218 * Our subsystem hierarchy is:
219 *
220 * /sys/kernel/config/netconsole/
221 * |
222 * <target>/
223 * | enabled
224 * | dev_name
225 * | local_port
226 * | remote_port
227 * | local_ip
228 * | remote_ip
229 * | local_mac
230 * | remote_mac
231 * |
232 * <target>/...
233 */
234
235struct netconsole_target_attr {
236 struct configfs_attribute attr;
237 ssize_t (*show)(struct netconsole_target *nt,
238 char *buf);
239 ssize_t (*store)(struct netconsole_target *nt,
240 const char *buf,
241 size_t count);
242};
243
244static struct netconsole_target *to_target(struct config_item *item)
245{
246 return item ?
247 container_of(item, struct netconsole_target, item) :
248 NULL;
249}
250
251/*
252 * Attribute operations for netconsole_target.
253 */
254
255static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
256{
257 return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
258}
259
260static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
261{
262 return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
263}
264
265static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
266{
267 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
268}
269
270static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
271{
272 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
273}
274
275static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
276{
277 if (nt->np.ipv6)
278 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
279 else
280 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
281}
282
283static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
284{
285 if (nt->np.ipv6)
286 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
287 else
288 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
289}
290
291static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
292{
293 struct net_device *dev = nt->np.dev;
294 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
295
296 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
297}
298
299static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
300{
301 return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
302}
303
304/*
305 * This one is special -- targets created through the configfs interface
306 * are not enabled (and the corresponding netpoll activated) by default.
307 * The user is expected to set the desired parameters first (which
308 * would enable him to dynamically add new netpoll targets for new
309 * network interfaces as and when they come up).
310 */
311static ssize_t store_enabled(struct netconsole_target *nt,
312 const char *buf,
313 size_t count)
314{
315 unsigned long flags;
316 int enabled;
317 int err;
318
319 err = kstrtoint(buf, 10, &enabled);
320 if (err < 0)
321 return err;
322 if (enabled < 0 || enabled > 1)
323 return -EINVAL;
324 if (enabled == nt->enabled) {
325 pr_info("network logging has already %s\n",
326 nt->enabled ? "started" : "stopped");
327 return -EINVAL;
328 }
329
330 if (enabled) { /* 1 */
331 /*
332 * Skip netpoll_parse_options() -- all the attributes are
333 * already configured via configfs. Just print them out.
334 */
335 netpoll_print_options(&nt->np);
336
337 err = netpoll_setup(&nt->np);
338 if (err)
339 return err;
340
341 pr_info("netconsole: network logging started\n");
342 } else { /* 0 */
343 /* We need to disable the netconsole before cleaning it up
344 * otherwise we might end up in write_msg() with
345 * nt->np.dev == NULL and nt->enabled == 1
346 */
347 spin_lock_irqsave(&target_list_lock, flags);
348 nt->enabled = 0;
349 spin_unlock_irqrestore(&target_list_lock, flags);
350 netpoll_cleanup(&nt->np);
351 }
352
353 nt->enabled = enabled;
354
355 return strnlen(buf, count);
356}
357
358static ssize_t store_dev_name(struct netconsole_target *nt,
359 const char *buf,
360 size_t count)
361{
362 size_t len;
363
364 if (nt->enabled) {
365 pr_err("target (%s) is enabled, disable to update parameters\n",
366 config_item_name(&nt->item));
367 return -EINVAL;
368 }
369
370 strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
371
372 /* Get rid of possible trailing newline from echo(1) */
373 len = strnlen(nt->np.dev_name, IFNAMSIZ);
374 if (nt->np.dev_name[len - 1] == '\n')
375 nt->np.dev_name[len - 1] = '\0';
376
377 return strnlen(buf, count);
378}
379
380static ssize_t store_local_port(struct netconsole_target *nt,
381 const char *buf,
382 size_t count)
383{
384 int rv;
385
386 if (nt->enabled) {
387 pr_err("target (%s) is enabled, disable to update parameters\n",
388 config_item_name(&nt->item));
389 return -EINVAL;
390 }
391
392 rv = kstrtou16(buf, 10, &nt->np.local_port);
393 if (rv < 0)
394 return rv;
395 return strnlen(buf, count);
396}
397
398static ssize_t store_remote_port(struct netconsole_target *nt,
399 const char *buf,
400 size_t count)
401{
402 int rv;
403
404 if (nt->enabled) {
405 pr_err("target (%s) is enabled, disable to update parameters\n",
406 config_item_name(&nt->item));
407 return -EINVAL;
408 }
409
410 rv = kstrtou16(buf, 10, &nt->np.remote_port);
411 if (rv < 0)
412 return rv;
413 return strnlen(buf, count);
414}
415
416static ssize_t store_local_ip(struct netconsole_target *nt,
417 const char *buf,
418 size_t count)
419{
420 if (nt->enabled) {
421 pr_err("target (%s) is enabled, disable to update parameters\n",
422 config_item_name(&nt->item));
423 return -EINVAL;
424 }
425
426 if (strnchr(buf, count, ':')) {
427 const char *end;
428 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
429 if (*end && *end != '\n') {
430 pr_err("invalid IPv6 address at: <%c>\n", *end);
431 return -EINVAL;
432 }
433 nt->np.ipv6 = true;
434 } else
435 return -EINVAL;
436 } else {
437 if (!nt->np.ipv6) {
438 nt->np.local_ip.ip = in_aton(buf);
439 } else
440 return -EINVAL;
441 }
442
443 return strnlen(buf, count);
444}
445
446static ssize_t store_remote_ip(struct netconsole_target *nt,
447 const char *buf,
448 size_t count)
449{
450 if (nt->enabled) {
451 pr_err("target (%s) is enabled, disable to update parameters\n",
452 config_item_name(&nt->item));
453 return -EINVAL;
454 }
455
456 if (strnchr(buf, count, ':')) {
457 const char *end;
458 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
459 if (*end && *end != '\n') {
460 pr_err("invalid IPv6 address at: <%c>\n", *end);
461 return -EINVAL;
462 }
463 nt->np.ipv6 = true;
464 } else
465 return -EINVAL;
466 } else {
467 if (!nt->np.ipv6) {
468 nt->np.remote_ip.ip = in_aton(buf);
469 } else
470 return -EINVAL;
471 }
472
473 return strnlen(buf, count);
474}
475
476static ssize_t store_remote_mac(struct netconsole_target *nt,
477 const char *buf,
478 size_t count)
479{
480 u8 remote_mac[ETH_ALEN];
481
482 if (nt->enabled) {
483 pr_err("target (%s) is enabled, disable to update parameters\n",
484 config_item_name(&nt->item));
485 return -EINVAL;
486 }
487
488 if (!mac_pton(buf, remote_mac))
489 return -EINVAL;
490 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
491 return -EINVAL;
492 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
493
494 return strnlen(buf, count);
495}
496
497/*
498 * Attribute definitions for netconsole_target.
499 */
500
501#define NETCONSOLE_TARGET_ATTR_RO(_name) \
502static struct netconsole_target_attr netconsole_target_##_name = \
503 __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
504
505#define NETCONSOLE_TARGET_ATTR_RW(_name) \
506static struct netconsole_target_attr netconsole_target_##_name = \
507 __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
508
509NETCONSOLE_TARGET_ATTR_RW(enabled);
510NETCONSOLE_TARGET_ATTR_RW(dev_name);
511NETCONSOLE_TARGET_ATTR_RW(local_port);
512NETCONSOLE_TARGET_ATTR_RW(remote_port);
513NETCONSOLE_TARGET_ATTR_RW(local_ip);
514NETCONSOLE_TARGET_ATTR_RW(remote_ip);
515NETCONSOLE_TARGET_ATTR_RO(local_mac);
516NETCONSOLE_TARGET_ATTR_RW(remote_mac);
517
518static struct configfs_attribute *netconsole_target_attrs[] = {
519 &netconsole_target_enabled.attr,
520 &netconsole_target_dev_name.attr,
521 &netconsole_target_local_port.attr,
522 &netconsole_target_remote_port.attr,
523 &netconsole_target_local_ip.attr,
524 &netconsole_target_remote_ip.attr,
525 &netconsole_target_local_mac.attr,
526 &netconsole_target_remote_mac.attr,
527 NULL,
528};
529
530/*
531 * Item operations and type for netconsole_target.
532 */
533
534static void netconsole_target_release(struct config_item *item)
535{
536 kfree(to_target(item));
537}
538
539static ssize_t netconsole_target_attr_show(struct config_item *item,
540 struct configfs_attribute *attr,
541 char *buf)
542{
543 ssize_t ret = -EINVAL;
544 struct netconsole_target *nt = to_target(item);
545 struct netconsole_target_attr *na =
546 container_of(attr, struct netconsole_target_attr, attr);
547
548 if (na->show)
549 ret = na->show(nt, buf);
550
551 return ret;
552}
553
554static ssize_t netconsole_target_attr_store(struct config_item *item,
555 struct configfs_attribute *attr,
556 const char *buf,
557 size_t count)
558{
559 ssize_t ret = -EINVAL;
560 struct netconsole_target *nt = to_target(item);
561 struct netconsole_target_attr *na =
562 container_of(attr, struct netconsole_target_attr, attr);
563
564 mutex_lock(&nt->mutex);
565 if (na->store)
566 ret = na->store(nt, buf, count);
567 mutex_unlock(&nt->mutex);
568
569 return ret;
570}
571
572static struct configfs_item_operations netconsole_target_item_ops = {
573 .release = netconsole_target_release,
574 .show_attribute = netconsole_target_attr_show,
575 .store_attribute = netconsole_target_attr_store,
576};
577
578static struct config_item_type netconsole_target_type = {
579 .ct_attrs = netconsole_target_attrs,
580 .ct_item_ops = &netconsole_target_item_ops,
581 .ct_owner = THIS_MODULE,
582};
583
584/*
585 * Group operations and type for netconsole_subsys.
586 */
587
588static struct config_item *make_netconsole_target(struct config_group *group,
589 const char *name)
590{
591 unsigned long flags;
592 struct netconsole_target *nt;
593
594 /*
595 * Allocate and initialize with defaults.
596 * Target is disabled at creation (enabled == 0).
597 */
598 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
599 if (!nt)
600 return ERR_PTR(-ENOMEM);
601
602 nt->np.name = "netconsole";
603 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
604 nt->np.local_port = 6665;
605 nt->np.remote_port = 6666;
606 mutex_init(&nt->mutex);
607 memset(nt->np.remote_mac, 0xff, ETH_ALEN);
608
609 /* Initialize the config_item member */
610 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
611
612 /* Adding, but it is disabled */
613 spin_lock_irqsave(&target_list_lock, flags);
614 list_add(&nt->list, &target_list);
615 spin_unlock_irqrestore(&target_list_lock, flags);
616
617 return &nt->item;
618}
619
620static void drop_netconsole_target(struct config_group *group,
621 struct config_item *item)
622{
623 unsigned long flags;
624 struct netconsole_target *nt = to_target(item);
625
626 spin_lock_irqsave(&target_list_lock, flags);
627 list_del(&nt->list);
628 spin_unlock_irqrestore(&target_list_lock, flags);
629
630 /*
631 * The target may have never been enabled, or was manually disabled
632 * before being removed so netpoll may have already been cleaned up.
633 */
634 if (nt->enabled)
635 netpoll_cleanup(&nt->np);
636
637 config_item_put(&nt->item);
638}
639
640static struct configfs_group_operations netconsole_subsys_group_ops = {
641 .make_item = make_netconsole_target,
642 .drop_item = drop_netconsole_target,
643};
644
645static struct config_item_type netconsole_subsys_type = {
646 .ct_group_ops = &netconsole_subsys_group_ops,
647 .ct_owner = THIS_MODULE,
648};
649
650/* The netconsole configfs subsystem */
651static struct configfs_subsystem netconsole_subsys = {
652 .su_group = {
653 .cg_item = {
654 .ci_namebuf = "netconsole",
655 .ci_type = &netconsole_subsys_type,
656 },
657 },
658};
659
660#endif /* CONFIG_NETCONSOLE_DYNAMIC */
661
662/* Handle network interface device notifications */
663static int netconsole_netdev_event(struct notifier_block *this,
664 unsigned long event, void *ptr)
665{
666 unsigned long flags;
667 struct netconsole_target *nt;
668 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
669 bool stopped = false;
670
671 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
672 event == NETDEV_RELEASE || event == NETDEV_JOIN))
673 goto done;
674
675 spin_lock_irqsave(&target_list_lock, flags);
676restart:
677 list_for_each_entry(nt, &target_list, list) {
678 netconsole_target_get(nt);
679 if (nt->np.dev == dev) {
680 switch (event) {
681 case NETDEV_CHANGENAME:
682 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
683 break;
684 case NETDEV_RELEASE:
685 case NETDEV_JOIN:
686 case NETDEV_UNREGISTER:
687 /* rtnl_lock already held
688 * we might sleep in __netpoll_cleanup()
689 */
690 spin_unlock_irqrestore(&target_list_lock, flags);
691
692 __netpoll_cleanup(&nt->np);
693
694 spin_lock_irqsave(&target_list_lock, flags);
695 dev_put(nt->np.dev);
696 nt->np.dev = NULL;
697 nt->enabled = 0;
698 stopped = true;
699 netconsole_target_put(nt);
700 goto restart;
701 }
702 }
703 netconsole_target_put(nt);
704 }
705 spin_unlock_irqrestore(&target_list_lock, flags);
706 if (stopped) {
707 const char *msg = "had an event";
708 switch (event) {
709 case NETDEV_UNREGISTER:
710 msg = "unregistered";
711 break;
712 case NETDEV_RELEASE:
713 msg = "released slaves";
714 break;
715 case NETDEV_JOIN:
716 msg = "is joining a master device";
717 break;
718 }
719 pr_info("network logging stopped on interface %s as it %s\n",
720 dev->name, msg);
721 }
722
723done:
724 return NOTIFY_DONE;
725}
726
727static struct notifier_block netconsole_netdev_notifier = {
728 .notifier_call = netconsole_netdev_event,
729};
730
731static void write_msg(struct console *con, const char *msg, unsigned int len)
732{
733 int frag, left;
734 unsigned long flags;
735 struct netconsole_target *nt;
736 const char *tmp;
737
738 if (oops_only && !oops_in_progress)
739 return;
740 /* Avoid taking lock and disabling interrupts unnecessarily */
741 if (list_empty(&target_list))
742 return;
743
744 spin_lock_irqsave(&target_list_lock, flags);
745 list_for_each_entry(nt, &target_list, list) {
746 netconsole_target_get(nt);
747 if (nt->enabled && netif_running(nt->np.dev)) {
748 /*
749 * We nest this inside the for-each-target loop above
750 * so that we're able to get as much logging out to
751 * at least one target if we die inside here, instead
752 * of unnecessarily keeping all targets in lock-step.
753 */
754 tmp = msg;
755 for (left = len; left;) {
756 frag = min(left, MAX_PRINT_CHUNK);
757 netpoll_send_udp(&nt->np, tmp, frag);
758 tmp += frag;
759 left -= frag;
760 }
761 }
762 netconsole_target_put(nt);
763 }
764 spin_unlock_irqrestore(&target_list_lock, flags);
765}
766
767static struct console netconsole = {
768 .name = "netcon",
769 .flags = CON_ENABLED,
770 .write = write_msg,
771};
772
773static int __init init_netconsole(void)
774{
775 int err;
776 struct netconsole_target *nt, *tmp;
777 unsigned long flags;
778 char *target_config;
779 char *input = config;
780
781 if (strnlen(input, MAX_PARAM_LENGTH)) {
782 while ((target_config = strsep(&input, ";"))) {
783 nt = alloc_param_target(target_config);
784 if (IS_ERR(nt)) {
785 err = PTR_ERR(nt);
786 goto fail;
787 }
788 /* Dump existing printks when we register */
789 netconsole.flags |= CON_PRINTBUFFER;
790
791 spin_lock_irqsave(&target_list_lock, flags);
792 list_add(&nt->list, &target_list);
793 spin_unlock_irqrestore(&target_list_lock, flags);
794 }
795 }
796
797 err = register_netdevice_notifier(&netconsole_netdev_notifier);
798 if (err)
799 goto fail;
800
801 err = dynamic_netconsole_init();
802 if (err)
803 goto undonotifier;
804
805 register_console(&netconsole);
806 pr_info("network logging started\n");
807
808 return err;
809
810undonotifier:
811 unregister_netdevice_notifier(&netconsole_netdev_notifier);
812
813fail:
814 pr_err("cleaning up\n");
815
816 /*
817 * Remove all targets and destroy them (only targets created
818 * from the boot/module option exist here). Skipping the list
819 * lock is safe here, and netpoll_cleanup() will sleep.
820 */
821 list_for_each_entry_safe(nt, tmp, &target_list, list) {
822 list_del(&nt->list);
823 free_param_target(nt);
824 }
825
826 return err;
827}
828
829static void __exit cleanup_netconsole(void)
830{
831 struct netconsole_target *nt, *tmp;
832
833 unregister_console(&netconsole);
834 dynamic_netconsole_exit();
835 unregister_netdevice_notifier(&netconsole_netdev_notifier);
836
837 /*
838 * Targets created via configfs pin references on our module
839 * and would first be rmdir(2)'ed from userspace. We reach
840 * here only when they are already destroyed, and only those
841 * created from the boot/module option are left, so remove and
842 * destroy them. Skipping the list lock is safe here, and
843 * netpoll_cleanup() will sleep.
844 */
845 list_for_each_entry_safe(nt, tmp, &target_list, list) {
846 list_del(&nt->list);
847 free_param_target(nt);
848 }
849}
850
851/*
852 * Use late_initcall to ensure netconsole is
853 * initialized after network device driver if built-in.
854 *
855 * late_initcall() and module_init() are identical if built as module.
856 */
857late_initcall(init_netconsole);
858module_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#include <linux/utsname.h>
40
41MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
42MODULE_DESCRIPTION("Console driver for network interfaces");
43MODULE_LICENSE("GPL");
44
45#define MAX_PARAM_LENGTH 256
46#define MAX_PRINT_CHUNK 1000
47
48static char config[MAX_PARAM_LENGTH];
49module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
50MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
51
52static bool oops_only = false;
53module_param(oops_only, bool, 0600);
54MODULE_PARM_DESC(oops_only, "Only log oops messages");
55
56#define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline"
57
58#ifndef MODULE
59static int __init option_setup(char *opt)
60{
61 strscpy(config, opt, MAX_PARAM_LENGTH);
62 return 1;
63}
64__setup("netconsole=", option_setup);
65#endif /* MODULE */
66
67/* Linked list of all configured targets */
68static LIST_HEAD(target_list);
69
70/* This needs to be a spinlock because write_msg() cannot sleep */
71static DEFINE_SPINLOCK(target_list_lock);
72
73/*
74 * Console driver for extended netconsoles. Registered on the first use to
75 * avoid unnecessarily enabling ext message formatting.
76 */
77static struct console netconsole_ext;
78
79/**
80 * struct netconsole_target - Represents a configured netconsole target.
81 * @list: Links this target into the target_list.
82 * @item: Links us into the configfs subsystem hierarchy.
83 * @enabled: On / off knob to enable / disable target.
84 * Visible from userspace (read-write).
85 * We maintain a strict 1:1 correspondence between this and
86 * whether the corresponding netpoll is active or inactive.
87 * Also, other parameters of a target may be modified at
88 * runtime only when it is disabled (enabled == 0).
89 * @extended: Denotes whether console is extended or not.
90 * @release: Denotes whether kernel release version should be prepended
91 * to the message. Depends on extended console.
92 * @np: The netpoll structure for this target.
93 * Contains the other userspace visible parameters:
94 * dev_name (read-write)
95 * local_port (read-write)
96 * remote_port (read-write)
97 * local_ip (read-write)
98 * remote_ip (read-write)
99 * local_mac (read-only)
100 * remote_mac (read-write)
101 */
102struct netconsole_target {
103 struct list_head list;
104#ifdef CONFIG_NETCONSOLE_DYNAMIC
105 struct config_item item;
106#endif
107 bool enabled;
108 bool extended;
109 bool release;
110 struct netpoll np;
111};
112
113#ifdef CONFIG_NETCONSOLE_DYNAMIC
114
115static struct configfs_subsystem netconsole_subsys;
116static DEFINE_MUTEX(dynamic_netconsole_mutex);
117
118static int __init dynamic_netconsole_init(void)
119{
120 config_group_init(&netconsole_subsys.su_group);
121 mutex_init(&netconsole_subsys.su_mutex);
122 return configfs_register_subsystem(&netconsole_subsys);
123}
124
125static void __exit dynamic_netconsole_exit(void)
126{
127 configfs_unregister_subsystem(&netconsole_subsys);
128}
129
130/*
131 * Targets that were created by parsing the boot/module option string
132 * do not exist in the configfs hierarchy (and have NULL names) and will
133 * never go away, so make these a no-op for them.
134 */
135static void netconsole_target_get(struct netconsole_target *nt)
136{
137 if (config_item_name(&nt->item))
138 config_item_get(&nt->item);
139}
140
141static void netconsole_target_put(struct netconsole_target *nt)
142{
143 if (config_item_name(&nt->item))
144 config_item_put(&nt->item);
145}
146
147#else /* !CONFIG_NETCONSOLE_DYNAMIC */
148
149static int __init dynamic_netconsole_init(void)
150{
151 return 0;
152}
153
154static void __exit dynamic_netconsole_exit(void)
155{
156}
157
158/*
159 * No danger of targets going away from under us when dynamic
160 * reconfigurability is off.
161 */
162static void netconsole_target_get(struct netconsole_target *nt)
163{
164}
165
166static void netconsole_target_put(struct netconsole_target *nt)
167{
168}
169
170static void populate_configfs_item(struct netconsole_target *nt,
171 int cmdline_count)
172{
173}
174#endif /* CONFIG_NETCONSOLE_DYNAMIC */
175
176/* Allocate and initialize with defaults.
177 * Note that these targets get their config_item fields zeroed-out.
178 */
179static struct netconsole_target *alloc_and_init(void)
180{
181 struct netconsole_target *nt;
182
183 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
184 if (!nt)
185 return nt;
186
187 if (IS_ENABLED(CONFIG_NETCONSOLE_EXTENDED_LOG))
188 nt->extended = true;
189 if (IS_ENABLED(CONFIG_NETCONSOLE_PREPEND_RELEASE))
190 nt->release = true;
191
192 nt->np.name = "netconsole";
193 strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
194 nt->np.local_port = 6665;
195 nt->np.remote_port = 6666;
196 eth_broadcast_addr(nt->np.remote_mac);
197
198 return nt;
199}
200
201#ifdef CONFIG_NETCONSOLE_DYNAMIC
202
203/*
204 * Our subsystem hierarchy is:
205 *
206 * /sys/kernel/config/netconsole/
207 * |
208 * <target>/
209 * | enabled
210 * | release
211 * | dev_name
212 * | local_port
213 * | remote_port
214 * | local_ip
215 * | remote_ip
216 * | local_mac
217 * | remote_mac
218 * |
219 * <target>/...
220 */
221
222static struct netconsole_target *to_target(struct config_item *item)
223{
224 return item ?
225 container_of(item, struct netconsole_target, item) :
226 NULL;
227}
228
229/*
230 * Attribute operations for netconsole_target.
231 */
232
233static ssize_t enabled_show(struct config_item *item, char *buf)
234{
235 return sysfs_emit(buf, "%d\n", to_target(item)->enabled);
236}
237
238static ssize_t extended_show(struct config_item *item, char *buf)
239{
240 return sysfs_emit(buf, "%d\n", to_target(item)->extended);
241}
242
243static ssize_t release_show(struct config_item *item, char *buf)
244{
245 return sysfs_emit(buf, "%d\n", to_target(item)->release);
246}
247
248static ssize_t dev_name_show(struct config_item *item, char *buf)
249{
250 return sysfs_emit(buf, "%s\n", to_target(item)->np.dev_name);
251}
252
253static ssize_t local_port_show(struct config_item *item, char *buf)
254{
255 return sysfs_emit(buf, "%d\n", to_target(item)->np.local_port);
256}
257
258static ssize_t remote_port_show(struct config_item *item, char *buf)
259{
260 return sysfs_emit(buf, "%d\n", to_target(item)->np.remote_port);
261}
262
263static ssize_t local_ip_show(struct config_item *item, char *buf)
264{
265 struct netconsole_target *nt = to_target(item);
266
267 if (nt->np.ipv6)
268 return sysfs_emit(buf, "%pI6c\n", &nt->np.local_ip.in6);
269 else
270 return sysfs_emit(buf, "%pI4\n", &nt->np.local_ip);
271}
272
273static ssize_t remote_ip_show(struct config_item *item, char *buf)
274{
275 struct netconsole_target *nt = to_target(item);
276
277 if (nt->np.ipv6)
278 return sysfs_emit(buf, "%pI6c\n", &nt->np.remote_ip.in6);
279 else
280 return sysfs_emit(buf, "%pI4\n", &nt->np.remote_ip);
281}
282
283static ssize_t local_mac_show(struct config_item *item, char *buf)
284{
285 struct net_device *dev = to_target(item)->np.dev;
286 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
287
288 return sysfs_emit(buf, "%pM\n", dev ? dev->dev_addr : bcast);
289}
290
291static ssize_t remote_mac_show(struct config_item *item, char *buf)
292{
293 return sysfs_emit(buf, "%pM\n", to_target(item)->np.remote_mac);
294}
295
296/*
297 * This one is special -- targets created through the configfs interface
298 * are not enabled (and the corresponding netpoll activated) by default.
299 * The user is expected to set the desired parameters first (which
300 * would enable him to dynamically add new netpoll targets for new
301 * network interfaces as and when they come up).
302 */
303static ssize_t enabled_store(struct config_item *item,
304 const char *buf, size_t count)
305{
306 struct netconsole_target *nt = to_target(item);
307 unsigned long flags;
308 bool enabled;
309 int err;
310
311 mutex_lock(&dynamic_netconsole_mutex);
312 err = kstrtobool(buf, &enabled);
313 if (err)
314 goto out_unlock;
315
316 err = -EINVAL;
317 if ((bool)enabled == nt->enabled) {
318 pr_info("network logging has already %s\n",
319 nt->enabled ? "started" : "stopped");
320 goto out_unlock;
321 }
322
323 if (enabled) { /* true */
324 if (nt->release && !nt->extended) {
325 pr_err("Not enabling netconsole. Release feature requires extended log message");
326 goto out_unlock;
327 }
328
329 if (nt->extended && !console_is_registered(&netconsole_ext))
330 register_console(&netconsole_ext);
331
332 /*
333 * Skip netpoll_parse_options() -- all the attributes are
334 * already configured via configfs. Just print them out.
335 */
336 netpoll_print_options(&nt->np);
337
338 err = netpoll_setup(&nt->np);
339 if (err)
340 goto out_unlock;
341
342 pr_info("network logging started\n");
343 } else { /* false */
344 /* We need to disable the netconsole before cleaning it up
345 * otherwise we might end up in write_msg() with
346 * nt->np.dev == NULL and nt->enabled == true
347 */
348 spin_lock_irqsave(&target_list_lock, flags);
349 nt->enabled = false;
350 spin_unlock_irqrestore(&target_list_lock, flags);
351 netpoll_cleanup(&nt->np);
352 }
353
354 nt->enabled = enabled;
355
356 mutex_unlock(&dynamic_netconsole_mutex);
357 return strnlen(buf, count);
358out_unlock:
359 mutex_unlock(&dynamic_netconsole_mutex);
360 return err;
361}
362
363static ssize_t release_store(struct config_item *item, const char *buf,
364 size_t count)
365{
366 struct netconsole_target *nt = to_target(item);
367 bool release;
368 int err;
369
370 mutex_lock(&dynamic_netconsole_mutex);
371 if (nt->enabled) {
372 pr_err("target (%s) is enabled, disable to update parameters\n",
373 config_item_name(&nt->item));
374 err = -EINVAL;
375 goto out_unlock;
376 }
377
378 err = kstrtobool(buf, &release);
379 if (err)
380 goto out_unlock;
381
382 nt->release = release;
383
384 mutex_unlock(&dynamic_netconsole_mutex);
385 return strnlen(buf, count);
386out_unlock:
387 mutex_unlock(&dynamic_netconsole_mutex);
388 return err;
389}
390
391static ssize_t extended_store(struct config_item *item, const char *buf,
392 size_t count)
393{
394 struct netconsole_target *nt = to_target(item);
395 bool extended;
396 int err;
397
398 mutex_lock(&dynamic_netconsole_mutex);
399 if (nt->enabled) {
400 pr_err("target (%s) is enabled, disable to update parameters\n",
401 config_item_name(&nt->item));
402 err = -EINVAL;
403 goto out_unlock;
404 }
405
406 err = kstrtobool(buf, &extended);
407 if (err)
408 goto out_unlock;
409
410 nt->extended = extended;
411
412 mutex_unlock(&dynamic_netconsole_mutex);
413 return strnlen(buf, count);
414out_unlock:
415 mutex_unlock(&dynamic_netconsole_mutex);
416 return err;
417}
418
419static ssize_t dev_name_store(struct config_item *item, const char *buf,
420 size_t count)
421{
422 struct netconsole_target *nt = to_target(item);
423 size_t len;
424
425 mutex_lock(&dynamic_netconsole_mutex);
426 if (nt->enabled) {
427 pr_err("target (%s) is enabled, disable to update parameters\n",
428 config_item_name(&nt->item));
429 mutex_unlock(&dynamic_netconsole_mutex);
430 return -EINVAL;
431 }
432
433 strscpy(nt->np.dev_name, buf, IFNAMSIZ);
434
435 /* Get rid of possible trailing newline from echo(1) */
436 len = strnlen(nt->np.dev_name, IFNAMSIZ);
437 if (nt->np.dev_name[len - 1] == '\n')
438 nt->np.dev_name[len - 1] = '\0';
439
440 mutex_unlock(&dynamic_netconsole_mutex);
441 return strnlen(buf, count);
442}
443
444static ssize_t local_port_store(struct config_item *item, const char *buf,
445 size_t count)
446{
447 struct netconsole_target *nt = to_target(item);
448 int rv = -EINVAL;
449
450 mutex_lock(&dynamic_netconsole_mutex);
451 if (nt->enabled) {
452 pr_err("target (%s) is enabled, disable to update parameters\n",
453 config_item_name(&nt->item));
454 goto out_unlock;
455 }
456
457 rv = kstrtou16(buf, 10, &nt->np.local_port);
458 if (rv < 0)
459 goto out_unlock;
460 mutex_unlock(&dynamic_netconsole_mutex);
461 return strnlen(buf, count);
462out_unlock:
463 mutex_unlock(&dynamic_netconsole_mutex);
464 return rv;
465}
466
467static ssize_t remote_port_store(struct config_item *item,
468 const char *buf, size_t count)
469{
470 struct netconsole_target *nt = to_target(item);
471 int rv = -EINVAL;
472
473 mutex_lock(&dynamic_netconsole_mutex);
474 if (nt->enabled) {
475 pr_err("target (%s) is enabled, disable to update parameters\n",
476 config_item_name(&nt->item));
477 goto out_unlock;
478 }
479
480 rv = kstrtou16(buf, 10, &nt->np.remote_port);
481 if (rv < 0)
482 goto out_unlock;
483 mutex_unlock(&dynamic_netconsole_mutex);
484 return strnlen(buf, count);
485out_unlock:
486 mutex_unlock(&dynamic_netconsole_mutex);
487 return rv;
488}
489
490static ssize_t local_ip_store(struct config_item *item, const char *buf,
491 size_t count)
492{
493 struct netconsole_target *nt = to_target(item);
494
495 mutex_lock(&dynamic_netconsole_mutex);
496 if (nt->enabled) {
497 pr_err("target (%s) is enabled, disable to update parameters\n",
498 config_item_name(&nt->item));
499 goto out_unlock;
500 }
501
502 if (strnchr(buf, count, ':')) {
503 const char *end;
504 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
505 if (*end && *end != '\n') {
506 pr_err("invalid IPv6 address at: <%c>\n", *end);
507 goto out_unlock;
508 }
509 nt->np.ipv6 = true;
510 } else
511 goto out_unlock;
512 } else {
513 if (!nt->np.ipv6) {
514 nt->np.local_ip.ip = in_aton(buf);
515 } else
516 goto out_unlock;
517 }
518
519 mutex_unlock(&dynamic_netconsole_mutex);
520 return strnlen(buf, count);
521out_unlock:
522 mutex_unlock(&dynamic_netconsole_mutex);
523 return -EINVAL;
524}
525
526static ssize_t remote_ip_store(struct config_item *item, const char *buf,
527 size_t count)
528{
529 struct netconsole_target *nt = to_target(item);
530
531 mutex_lock(&dynamic_netconsole_mutex);
532 if (nt->enabled) {
533 pr_err("target (%s) is enabled, disable to update parameters\n",
534 config_item_name(&nt->item));
535 goto out_unlock;
536 }
537
538 if (strnchr(buf, count, ':')) {
539 const char *end;
540 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
541 if (*end && *end != '\n') {
542 pr_err("invalid IPv6 address at: <%c>\n", *end);
543 goto out_unlock;
544 }
545 nt->np.ipv6 = true;
546 } else
547 goto out_unlock;
548 } else {
549 if (!nt->np.ipv6) {
550 nt->np.remote_ip.ip = in_aton(buf);
551 } else
552 goto out_unlock;
553 }
554
555 mutex_unlock(&dynamic_netconsole_mutex);
556 return strnlen(buf, count);
557out_unlock:
558 mutex_unlock(&dynamic_netconsole_mutex);
559 return -EINVAL;
560}
561
562static ssize_t remote_mac_store(struct config_item *item, const char *buf,
563 size_t count)
564{
565 struct netconsole_target *nt = to_target(item);
566 u8 remote_mac[ETH_ALEN];
567
568 mutex_lock(&dynamic_netconsole_mutex);
569 if (nt->enabled) {
570 pr_err("target (%s) is enabled, disable to update parameters\n",
571 config_item_name(&nt->item));
572 goto out_unlock;
573 }
574
575 if (!mac_pton(buf, remote_mac))
576 goto out_unlock;
577 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
578 goto out_unlock;
579 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
580
581 mutex_unlock(&dynamic_netconsole_mutex);
582 return strnlen(buf, count);
583out_unlock:
584 mutex_unlock(&dynamic_netconsole_mutex);
585 return -EINVAL;
586}
587
588CONFIGFS_ATTR(, enabled);
589CONFIGFS_ATTR(, extended);
590CONFIGFS_ATTR(, dev_name);
591CONFIGFS_ATTR(, local_port);
592CONFIGFS_ATTR(, remote_port);
593CONFIGFS_ATTR(, local_ip);
594CONFIGFS_ATTR(, remote_ip);
595CONFIGFS_ATTR_RO(, local_mac);
596CONFIGFS_ATTR(, remote_mac);
597CONFIGFS_ATTR(, release);
598
599static struct configfs_attribute *netconsole_target_attrs[] = {
600 &attr_enabled,
601 &attr_extended,
602 &attr_release,
603 &attr_dev_name,
604 &attr_local_port,
605 &attr_remote_port,
606 &attr_local_ip,
607 &attr_remote_ip,
608 &attr_local_mac,
609 &attr_remote_mac,
610 NULL,
611};
612
613/*
614 * Item operations and type for netconsole_target.
615 */
616
617static void netconsole_target_release(struct config_item *item)
618{
619 kfree(to_target(item));
620}
621
622static struct configfs_item_operations netconsole_target_item_ops = {
623 .release = netconsole_target_release,
624};
625
626static const struct config_item_type netconsole_target_type = {
627 .ct_attrs = netconsole_target_attrs,
628 .ct_item_ops = &netconsole_target_item_ops,
629 .ct_owner = THIS_MODULE,
630};
631
632static struct netconsole_target *find_cmdline_target(const char *name)
633{
634 struct netconsole_target *nt, *ret = NULL;
635 unsigned long flags;
636
637 spin_lock_irqsave(&target_list_lock, flags);
638 list_for_each_entry(nt, &target_list, list) {
639 if (!strcmp(nt->item.ci_name, name)) {
640 ret = nt;
641 break;
642 }
643 }
644 spin_unlock_irqrestore(&target_list_lock, flags);
645
646 return ret;
647}
648
649/*
650 * Group operations and type for netconsole_subsys.
651 */
652
653static struct config_item *make_netconsole_target(struct config_group *group,
654 const char *name)
655{
656 struct netconsole_target *nt;
657 unsigned long flags;
658
659 /* Checking if a target by this name was created at boot time. If so,
660 * attach a configfs entry to that target. This enables dynamic
661 * control.
662 */
663 if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX,
664 strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
665 nt = find_cmdline_target(name);
666 if (nt)
667 return &nt->item;
668 }
669
670 nt = alloc_and_init();
671 if (!nt)
672 return ERR_PTR(-ENOMEM);
673
674 /* Initialize the config_item member */
675 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
676
677 /* Adding, but it is disabled */
678 spin_lock_irqsave(&target_list_lock, flags);
679 list_add(&nt->list, &target_list);
680 spin_unlock_irqrestore(&target_list_lock, flags);
681
682 return &nt->item;
683}
684
685static void drop_netconsole_target(struct config_group *group,
686 struct config_item *item)
687{
688 unsigned long flags;
689 struct netconsole_target *nt = to_target(item);
690
691 spin_lock_irqsave(&target_list_lock, flags);
692 list_del(&nt->list);
693 spin_unlock_irqrestore(&target_list_lock, flags);
694
695 /*
696 * The target may have never been enabled, or was manually disabled
697 * before being removed so netpoll may have already been cleaned up.
698 */
699 if (nt->enabled)
700 netpoll_cleanup(&nt->np);
701
702 config_item_put(&nt->item);
703}
704
705static struct configfs_group_operations netconsole_subsys_group_ops = {
706 .make_item = make_netconsole_target,
707 .drop_item = drop_netconsole_target,
708};
709
710static const struct config_item_type netconsole_subsys_type = {
711 .ct_group_ops = &netconsole_subsys_group_ops,
712 .ct_owner = THIS_MODULE,
713};
714
715/* The netconsole configfs subsystem */
716static struct configfs_subsystem netconsole_subsys = {
717 .su_group = {
718 .cg_item = {
719 .ci_namebuf = "netconsole",
720 .ci_type = &netconsole_subsys_type,
721 },
722 },
723};
724
725static void populate_configfs_item(struct netconsole_target *nt,
726 int cmdline_count)
727{
728 char target_name[16];
729
730 snprintf(target_name, sizeof(target_name), "%s%d",
731 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
732 config_item_init_type_name(&nt->item, target_name,
733 &netconsole_target_type);
734}
735
736#endif /* CONFIG_NETCONSOLE_DYNAMIC */
737
738/* Handle network interface device notifications */
739static int netconsole_netdev_event(struct notifier_block *this,
740 unsigned long event, void *ptr)
741{
742 unsigned long flags;
743 struct netconsole_target *nt;
744 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
745 bool stopped = false;
746
747 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
748 event == NETDEV_RELEASE || event == NETDEV_JOIN))
749 goto done;
750
751 spin_lock_irqsave(&target_list_lock, flags);
752restart:
753 list_for_each_entry(nt, &target_list, list) {
754 netconsole_target_get(nt);
755 if (nt->np.dev == dev) {
756 switch (event) {
757 case NETDEV_CHANGENAME:
758 strscpy(nt->np.dev_name, dev->name, IFNAMSIZ);
759 break;
760 case NETDEV_RELEASE:
761 case NETDEV_JOIN:
762 case NETDEV_UNREGISTER:
763 /* rtnl_lock already held
764 * we might sleep in __netpoll_cleanup()
765 */
766 spin_unlock_irqrestore(&target_list_lock, flags);
767
768 __netpoll_cleanup(&nt->np);
769
770 spin_lock_irqsave(&target_list_lock, flags);
771 netdev_put(nt->np.dev, &nt->np.dev_tracker);
772 nt->np.dev = NULL;
773 nt->enabled = false;
774 stopped = true;
775 netconsole_target_put(nt);
776 goto restart;
777 }
778 }
779 netconsole_target_put(nt);
780 }
781 spin_unlock_irqrestore(&target_list_lock, flags);
782 if (stopped) {
783 const char *msg = "had an event";
784 switch (event) {
785 case NETDEV_UNREGISTER:
786 msg = "unregistered";
787 break;
788 case NETDEV_RELEASE:
789 msg = "released slaves";
790 break;
791 case NETDEV_JOIN:
792 msg = "is joining a master device";
793 break;
794 }
795 pr_info("network logging stopped on interface %s as it %s\n",
796 dev->name, msg);
797 }
798
799done:
800 return NOTIFY_DONE;
801}
802
803static struct notifier_block netconsole_netdev_notifier = {
804 .notifier_call = netconsole_netdev_event,
805};
806
807/**
808 * send_ext_msg_udp - send extended log message to target
809 * @nt: target to send message to
810 * @msg: extended log message to send
811 * @msg_len: length of message
812 *
813 * Transfer extended log @msg to @nt. If @msg is longer than
814 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
815 * ncfrag header field added to identify them.
816 */
817static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
818 int msg_len)
819{
820 static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
821 const char *header, *body;
822 int offset = 0;
823 int header_len, body_len;
824 const char *msg_ready = msg;
825 const char *release;
826 int release_len = 0;
827
828 if (nt->release) {
829 release = init_utsname()->release;
830 release_len = strlen(release) + 1;
831 }
832
833 if (msg_len + release_len <= MAX_PRINT_CHUNK) {
834 /* No fragmentation needed */
835 if (nt->release) {
836 scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg);
837 msg_len += release_len;
838 msg_ready = buf;
839 }
840 netpoll_send_udp(&nt->np, msg_ready, msg_len);
841 return;
842 }
843
844 /* need to insert extra header fields, detect header and body */
845 header = msg;
846 body = memchr(msg, ';', msg_len);
847 if (WARN_ON_ONCE(!body))
848 return;
849
850 header_len = body - header;
851 body_len = msg_len - header_len - 1;
852 body++;
853
854 /*
855 * Transfer multiple chunks with the following extra header.
856 * "ncfrag=<byte-offset>/<total-bytes>"
857 */
858 if (nt->release)
859 scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
860 memcpy(buf + release_len, header, header_len);
861 header_len += release_len;
862
863 while (offset < body_len) {
864 int this_header = header_len;
865 int this_chunk;
866
867 this_header += scnprintf(buf + this_header,
868 sizeof(buf) - this_header,
869 ",ncfrag=%d/%d;", offset, body_len);
870
871 this_chunk = min(body_len - offset,
872 MAX_PRINT_CHUNK - this_header);
873 if (WARN_ON_ONCE(this_chunk <= 0))
874 return;
875
876 memcpy(buf + this_header, body + offset, this_chunk);
877
878 netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
879
880 offset += this_chunk;
881 }
882}
883
884static void write_ext_msg(struct console *con, const char *msg,
885 unsigned int len)
886{
887 struct netconsole_target *nt;
888 unsigned long flags;
889
890 if ((oops_only && !oops_in_progress) || list_empty(&target_list))
891 return;
892
893 spin_lock_irqsave(&target_list_lock, flags);
894 list_for_each_entry(nt, &target_list, list)
895 if (nt->extended && nt->enabled && netif_running(nt->np.dev))
896 send_ext_msg_udp(nt, msg, len);
897 spin_unlock_irqrestore(&target_list_lock, flags);
898}
899
900static void write_msg(struct console *con, const char *msg, unsigned int len)
901{
902 int frag, left;
903 unsigned long flags;
904 struct netconsole_target *nt;
905 const char *tmp;
906
907 if (oops_only && !oops_in_progress)
908 return;
909 /* Avoid taking lock and disabling interrupts unnecessarily */
910 if (list_empty(&target_list))
911 return;
912
913 spin_lock_irqsave(&target_list_lock, flags);
914 list_for_each_entry(nt, &target_list, list) {
915 if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
916 /*
917 * We nest this inside the for-each-target loop above
918 * so that we're able to get as much logging out to
919 * at least one target if we die inside here, instead
920 * of unnecessarily keeping all targets in lock-step.
921 */
922 tmp = msg;
923 for (left = len; left;) {
924 frag = min(left, MAX_PRINT_CHUNK);
925 netpoll_send_udp(&nt->np, tmp, frag);
926 tmp += frag;
927 left -= frag;
928 }
929 }
930 }
931 spin_unlock_irqrestore(&target_list_lock, flags);
932}
933
934/* Allocate new target (from boot/module param) and setup netpoll for it */
935static struct netconsole_target *alloc_param_target(char *target_config,
936 int cmdline_count)
937{
938 struct netconsole_target *nt;
939 int err;
940
941 nt = alloc_and_init();
942 if (!nt) {
943 err = -ENOMEM;
944 goto fail;
945 }
946
947 if (*target_config == '+') {
948 nt->extended = true;
949 target_config++;
950 }
951
952 if (*target_config == 'r') {
953 if (!nt->extended) {
954 pr_err("Netconsole configuration error. Release feature requires extended log message");
955 err = -EINVAL;
956 goto fail;
957 }
958 nt->release = true;
959 target_config++;
960 }
961
962 /* Parse parameters and setup netpoll */
963 err = netpoll_parse_options(&nt->np, target_config);
964 if (err)
965 goto fail;
966
967 err = netpoll_setup(&nt->np);
968 if (err)
969 goto fail;
970
971 populate_configfs_item(nt, cmdline_count);
972 nt->enabled = true;
973
974 return nt;
975
976fail:
977 kfree(nt);
978 return ERR_PTR(err);
979}
980
981/* Cleanup netpoll for given target (from boot/module param) and free it */
982static void free_param_target(struct netconsole_target *nt)
983{
984 netpoll_cleanup(&nt->np);
985 kfree(nt);
986}
987
988static struct console netconsole_ext = {
989 .name = "netcon_ext",
990 .flags = CON_ENABLED | CON_EXTENDED,
991 .write = write_ext_msg,
992};
993
994static struct console netconsole = {
995 .name = "netcon",
996 .flags = CON_ENABLED,
997 .write = write_msg,
998};
999
1000static int __init init_netconsole(void)
1001{
1002 int err;
1003 struct netconsole_target *nt, *tmp;
1004 unsigned int count = 0;
1005 bool extended = false;
1006 unsigned long flags;
1007 char *target_config;
1008 char *input = config;
1009
1010 if (strnlen(input, MAX_PARAM_LENGTH)) {
1011 while ((target_config = strsep(&input, ";"))) {
1012 nt = alloc_param_target(target_config, count);
1013 if (IS_ERR(nt)) {
1014 err = PTR_ERR(nt);
1015 goto fail;
1016 }
1017 /* Dump existing printks when we register */
1018 if (nt->extended) {
1019 extended = true;
1020 netconsole_ext.flags |= CON_PRINTBUFFER;
1021 } else {
1022 netconsole.flags |= CON_PRINTBUFFER;
1023 }
1024
1025 spin_lock_irqsave(&target_list_lock, flags);
1026 list_add(&nt->list, &target_list);
1027 spin_unlock_irqrestore(&target_list_lock, flags);
1028 count++;
1029 }
1030 }
1031
1032 err = register_netdevice_notifier(&netconsole_netdev_notifier);
1033 if (err)
1034 goto fail;
1035
1036 err = dynamic_netconsole_init();
1037 if (err)
1038 goto undonotifier;
1039
1040 if (extended)
1041 register_console(&netconsole_ext);
1042 register_console(&netconsole);
1043 pr_info("network logging started\n");
1044
1045 return err;
1046
1047undonotifier:
1048 unregister_netdevice_notifier(&netconsole_netdev_notifier);
1049
1050fail:
1051 pr_err("cleaning up\n");
1052
1053 /*
1054 * Remove all targets and destroy them (only targets created
1055 * from the boot/module option exist here). Skipping the list
1056 * lock is safe here, and netpoll_cleanup() will sleep.
1057 */
1058 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1059 list_del(&nt->list);
1060 free_param_target(nt);
1061 }
1062
1063 return err;
1064}
1065
1066static void __exit cleanup_netconsole(void)
1067{
1068 struct netconsole_target *nt, *tmp;
1069
1070 if (console_is_registered(&netconsole_ext))
1071 unregister_console(&netconsole_ext);
1072 unregister_console(&netconsole);
1073 dynamic_netconsole_exit();
1074 unregister_netdevice_notifier(&netconsole_netdev_notifier);
1075
1076 /*
1077 * Targets created via configfs pin references on our module
1078 * and would first be rmdir(2)'ed from userspace. We reach
1079 * here only when they are already destroyed, and only those
1080 * created from the boot/module option are left, so remove and
1081 * destroy them. Skipping the list lock is safe here, and
1082 * netpoll_cleanup() will sleep.
1083 */
1084 list_for_each_entry_safe(nt, tmp, &target_list, list) {
1085 list_del(&nt->list);
1086 free_param_target(nt);
1087 }
1088}
1089
1090/*
1091 * Use late_initcall to ensure netconsole is
1092 * initialized after network device driver if built-in.
1093 *
1094 * late_initcall() and module_init() are identical if built as module.
1095 */
1096late_initcall(init_netconsole);
1097module_exit(cleanup_netconsole);