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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#include <linux/mm.h>
38#include <linux/init.h>
39#include <linux/module.h>
40#include <linux/slab.h>
41#include <linux/console.h>
42#include <linux/moduleparam.h>
43#include <linux/string.h>
44#include <linux/netpoll.h>
45#include <linux/inet.h>
46#include <linux/configfs.h>
47
48MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
49MODULE_DESCRIPTION("Console driver for network interfaces");
50MODULE_LICENSE("GPL");
51
52#define MAX_PARAM_LENGTH 256
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
59#ifndef MODULE
60static int __init option_setup(char *opt)
61{
62 strlcpy(config, opt, MAX_PARAM_LENGTH);
63 return 1;
64}
65__setup("netconsole=", option_setup);
66#endif /* MODULE */
67
68/* Linked list of all configured targets */
69static LIST_HEAD(target_list);
70
71/* This needs to be a spinlock because write_msg() cannot sleep */
72static DEFINE_SPINLOCK(target_list_lock);
73
74/**
75 * struct netconsole_target - Represents a configured netconsole target.
76 * @list: Links this target into the target_list.
77 * @item: Links us into the configfs subsystem hierarchy.
78 * @enabled: On / off knob to enable / disable target.
79 * Visible from userspace (read-write).
80 * We maintain a strict 1:1 correspondence between this and
81 * whether the corresponding netpoll is active or inactive.
82 * Also, other parameters of a target may be modified at
83 * runtime only when it is disabled (enabled == 0).
84 * @np: The netpoll structure for this target.
85 * Contains the other userspace visible parameters:
86 * dev_name (read-write)
87 * local_port (read-write)
88 * remote_port (read-write)
89 * local_ip (read-write)
90 * remote_ip (read-write)
91 * local_mac (read-only)
92 * remote_mac (read-write)
93 */
94struct netconsole_target {
95 struct list_head list;
96#ifdef CONFIG_NETCONSOLE_DYNAMIC
97 struct config_item item;
98#endif
99 int enabled;
100 struct netpoll np;
101};
102
103#ifdef CONFIG_NETCONSOLE_DYNAMIC
104
105static struct configfs_subsystem netconsole_subsys;
106
107static int __init dynamic_netconsole_init(void)
108{
109 config_group_init(&netconsole_subsys.su_group);
110 mutex_init(&netconsole_subsys.su_mutex);
111 return configfs_register_subsystem(&netconsole_subsys);
112}
113
114static void __exit dynamic_netconsole_exit(void)
115{
116 configfs_unregister_subsystem(&netconsole_subsys);
117}
118
119/*
120 * Targets that were created by parsing the boot/module option string
121 * do not exist in the configfs hierarchy (and have NULL names) and will
122 * never go away, so make these a no-op for them.
123 */
124static void netconsole_target_get(struct netconsole_target *nt)
125{
126 if (config_item_name(&nt->item))
127 config_item_get(&nt->item);
128}
129
130static void netconsole_target_put(struct netconsole_target *nt)
131{
132 if (config_item_name(&nt->item))
133 config_item_put(&nt->item);
134}
135
136#else /* !CONFIG_NETCONSOLE_DYNAMIC */
137
138static int __init dynamic_netconsole_init(void)
139{
140 return 0;
141}
142
143static void __exit dynamic_netconsole_exit(void)
144{
145}
146
147/*
148 * No danger of targets going away from under us when dynamic
149 * reconfigurability is off.
150 */
151static void netconsole_target_get(struct netconsole_target *nt)
152{
153}
154
155static void netconsole_target_put(struct netconsole_target *nt)
156{
157}
158
159#endif /* CONFIG_NETCONSOLE_DYNAMIC */
160
161/* Allocate new target (from boot/module param) and setup netpoll for it */
162static struct netconsole_target *alloc_param_target(char *target_config)
163{
164 int err = -ENOMEM;
165 struct netconsole_target *nt;
166
167 /*
168 * Allocate and initialize with defaults.
169 * Note that these targets get their config_item fields zeroed-out.
170 */
171 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
172 if (!nt) {
173 printk(KERN_ERR "netconsole: failed to allocate memory\n");
174 goto fail;
175 }
176
177 nt->np.name = "netconsole";
178 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
179 nt->np.local_port = 6665;
180 nt->np.remote_port = 6666;
181 memset(nt->np.remote_mac, 0xff, ETH_ALEN);
182
183 /* Parse parameters and setup netpoll */
184 err = netpoll_parse_options(&nt->np, target_config);
185 if (err)
186 goto fail;
187
188 err = netpoll_setup(&nt->np);
189 if (err)
190 goto fail;
191
192 nt->enabled = 1;
193
194 return nt;
195
196fail:
197 kfree(nt);
198 return ERR_PTR(err);
199}
200
201/* Cleanup netpoll for given target (from boot/module param) and free it */
202static void free_param_target(struct netconsole_target *nt)
203{
204 netpoll_cleanup(&nt->np);
205 kfree(nt);
206}
207
208#ifdef CONFIG_NETCONSOLE_DYNAMIC
209
210/*
211 * Our subsystem hierarchy is:
212 *
213 * /sys/kernel/config/netconsole/
214 * |
215 * <target>/
216 * | enabled
217 * | dev_name
218 * | local_port
219 * | remote_port
220 * | local_ip
221 * | remote_ip
222 * | local_mac
223 * | remote_mac
224 * |
225 * <target>/...
226 */
227
228struct netconsole_target_attr {
229 struct configfs_attribute attr;
230 ssize_t (*show)(struct netconsole_target *nt,
231 char *buf);
232 ssize_t (*store)(struct netconsole_target *nt,
233 const char *buf,
234 size_t count);
235};
236
237static struct netconsole_target *to_target(struct config_item *item)
238{
239 return item ?
240 container_of(item, struct netconsole_target, item) :
241 NULL;
242}
243
244/*
245 * Attribute operations for netconsole_target.
246 */
247
248static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
249{
250 return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
251}
252
253static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
254{
255 return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
256}
257
258static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
259{
260 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
261}
262
263static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
264{
265 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
266}
267
268static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
269{
270 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
271}
272
273static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
274{
275 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
276}
277
278static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
279{
280 struct net_device *dev = nt->np.dev;
281 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
282
283 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
284}
285
286static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
287{
288 return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
289}
290
291/*
292 * This one is special -- targets created through the configfs interface
293 * are not enabled (and the corresponding netpoll activated) by default.
294 * The user is expected to set the desired parameters first (which
295 * would enable him to dynamically add new netpoll targets for new
296 * network interfaces as and when they come up).
297 */
298static ssize_t store_enabled(struct netconsole_target *nt,
299 const char *buf,
300 size_t count)
301{
302 int enabled;
303 int err;
304
305 err = kstrtoint(buf, 10, &enabled);
306 if (err < 0)
307 return err;
308 if (enabled < 0 || enabled > 1)
309 return -EINVAL;
310 if (enabled == nt->enabled) {
311 printk(KERN_INFO "netconsole: network logging has already %s\n",
312 nt->enabled ? "started" : "stopped");
313 return -EINVAL;
314 }
315
316 if (enabled) { /* 1 */
317
318 /*
319 * Skip netpoll_parse_options() -- all the attributes are
320 * already configured via configfs. Just print them out.
321 */
322 netpoll_print_options(&nt->np);
323
324 err = netpoll_setup(&nt->np);
325 if (err)
326 return err;
327
328 printk(KERN_INFO "netconsole: network logging started\n");
329
330 } else { /* 0 */
331 netpoll_cleanup(&nt->np);
332 }
333
334 nt->enabled = enabled;
335
336 return strnlen(buf, count);
337}
338
339static ssize_t store_dev_name(struct netconsole_target *nt,
340 const char *buf,
341 size_t count)
342{
343 size_t len;
344
345 if (nt->enabled) {
346 printk(KERN_ERR "netconsole: target (%s) is enabled, "
347 "disable to update parameters\n",
348 config_item_name(&nt->item));
349 return -EINVAL;
350 }
351
352 strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
353
354 /* Get rid of possible trailing newline from echo(1) */
355 len = strnlen(nt->np.dev_name, IFNAMSIZ);
356 if (nt->np.dev_name[len - 1] == '\n')
357 nt->np.dev_name[len - 1] = '\0';
358
359 return strnlen(buf, count);
360}
361
362static ssize_t store_local_port(struct netconsole_target *nt,
363 const char *buf,
364 size_t count)
365{
366 int rv;
367
368 if (nt->enabled) {
369 printk(KERN_ERR "netconsole: target (%s) is enabled, "
370 "disable to update parameters\n",
371 config_item_name(&nt->item));
372 return -EINVAL;
373 }
374
375 rv = kstrtou16(buf, 10, &nt->np.local_port);
376 if (rv < 0)
377 return rv;
378 return strnlen(buf, count);
379}
380
381static ssize_t store_remote_port(struct netconsole_target *nt,
382 const char *buf,
383 size_t count)
384{
385 int rv;
386
387 if (nt->enabled) {
388 printk(KERN_ERR "netconsole: target (%s) is enabled, "
389 "disable to update parameters\n",
390 config_item_name(&nt->item));
391 return -EINVAL;
392 }
393
394 rv = kstrtou16(buf, 10, &nt->np.remote_port);
395 if (rv < 0)
396 return rv;
397 return strnlen(buf, count);
398}
399
400static ssize_t store_local_ip(struct netconsole_target *nt,
401 const char *buf,
402 size_t count)
403{
404 if (nt->enabled) {
405 printk(KERN_ERR "netconsole: target (%s) is enabled, "
406 "disable to update parameters\n",
407 config_item_name(&nt->item));
408 return -EINVAL;
409 }
410
411 nt->np.local_ip = in_aton(buf);
412
413 return strnlen(buf, count);
414}
415
416static ssize_t store_remote_ip(struct netconsole_target *nt,
417 const char *buf,
418 size_t count)
419{
420 if (nt->enabled) {
421 printk(KERN_ERR "netconsole: target (%s) is enabled, "
422 "disable to update parameters\n",
423 config_item_name(&nt->item));
424 return -EINVAL;
425 }
426
427 nt->np.remote_ip = in_aton(buf);
428
429 return strnlen(buf, count);
430}
431
432static ssize_t store_remote_mac(struct netconsole_target *nt,
433 const char *buf,
434 size_t count)
435{
436 u8 remote_mac[ETH_ALEN];
437
438 if (nt->enabled) {
439 printk(KERN_ERR "netconsole: target (%s) is enabled, "
440 "disable to update parameters\n",
441 config_item_name(&nt->item));
442 return -EINVAL;
443 }
444
445 if (!mac_pton(buf, remote_mac))
446 return -EINVAL;
447 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
448 return -EINVAL;
449 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
450
451 return strnlen(buf, count);
452}
453
454/*
455 * Attribute definitions for netconsole_target.
456 */
457
458#define NETCONSOLE_TARGET_ATTR_RO(_name) \
459static struct netconsole_target_attr netconsole_target_##_name = \
460 __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
461
462#define NETCONSOLE_TARGET_ATTR_RW(_name) \
463static struct netconsole_target_attr netconsole_target_##_name = \
464 __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
465
466NETCONSOLE_TARGET_ATTR_RW(enabled);
467NETCONSOLE_TARGET_ATTR_RW(dev_name);
468NETCONSOLE_TARGET_ATTR_RW(local_port);
469NETCONSOLE_TARGET_ATTR_RW(remote_port);
470NETCONSOLE_TARGET_ATTR_RW(local_ip);
471NETCONSOLE_TARGET_ATTR_RW(remote_ip);
472NETCONSOLE_TARGET_ATTR_RO(local_mac);
473NETCONSOLE_TARGET_ATTR_RW(remote_mac);
474
475static struct configfs_attribute *netconsole_target_attrs[] = {
476 &netconsole_target_enabled.attr,
477 &netconsole_target_dev_name.attr,
478 &netconsole_target_local_port.attr,
479 &netconsole_target_remote_port.attr,
480 &netconsole_target_local_ip.attr,
481 &netconsole_target_remote_ip.attr,
482 &netconsole_target_local_mac.attr,
483 &netconsole_target_remote_mac.attr,
484 NULL,
485};
486
487/*
488 * Item operations and type for netconsole_target.
489 */
490
491static void netconsole_target_release(struct config_item *item)
492{
493 kfree(to_target(item));
494}
495
496static ssize_t netconsole_target_attr_show(struct config_item *item,
497 struct configfs_attribute *attr,
498 char *buf)
499{
500 ssize_t ret = -EINVAL;
501 struct netconsole_target *nt = to_target(item);
502 struct netconsole_target_attr *na =
503 container_of(attr, struct netconsole_target_attr, attr);
504
505 if (na->show)
506 ret = na->show(nt, buf);
507
508 return ret;
509}
510
511static ssize_t netconsole_target_attr_store(struct config_item *item,
512 struct configfs_attribute *attr,
513 const char *buf,
514 size_t count)
515{
516 ssize_t ret = -EINVAL;
517 struct netconsole_target *nt = to_target(item);
518 struct netconsole_target_attr *na =
519 container_of(attr, struct netconsole_target_attr, attr);
520
521 if (na->store)
522 ret = na->store(nt, buf, count);
523
524 return ret;
525}
526
527static struct configfs_item_operations netconsole_target_item_ops = {
528 .release = netconsole_target_release,
529 .show_attribute = netconsole_target_attr_show,
530 .store_attribute = netconsole_target_attr_store,
531};
532
533static struct config_item_type netconsole_target_type = {
534 .ct_attrs = netconsole_target_attrs,
535 .ct_item_ops = &netconsole_target_item_ops,
536 .ct_owner = THIS_MODULE,
537};
538
539/*
540 * Group operations and type for netconsole_subsys.
541 */
542
543static struct config_item *make_netconsole_target(struct config_group *group,
544 const char *name)
545{
546 unsigned long flags;
547 struct netconsole_target *nt;
548
549 /*
550 * Allocate and initialize with defaults.
551 * Target is disabled at creation (enabled == 0).
552 */
553 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
554 if (!nt) {
555 printk(KERN_ERR "netconsole: failed to allocate memory\n");
556 return ERR_PTR(-ENOMEM);
557 }
558
559 nt->np.name = "netconsole";
560 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
561 nt->np.local_port = 6665;
562 nt->np.remote_port = 6666;
563 memset(nt->np.remote_mac, 0xff, ETH_ALEN);
564
565 /* Initialize the config_item member */
566 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
567
568 /* Adding, but it is disabled */
569 spin_lock_irqsave(&target_list_lock, flags);
570 list_add(&nt->list, &target_list);
571 spin_unlock_irqrestore(&target_list_lock, flags);
572
573 return &nt->item;
574}
575
576static void drop_netconsole_target(struct config_group *group,
577 struct config_item *item)
578{
579 unsigned long flags;
580 struct netconsole_target *nt = to_target(item);
581
582 spin_lock_irqsave(&target_list_lock, flags);
583 list_del(&nt->list);
584 spin_unlock_irqrestore(&target_list_lock, flags);
585
586 /*
587 * The target may have never been enabled, or was manually disabled
588 * before being removed so netpoll may have already been cleaned up.
589 */
590 if (nt->enabled)
591 netpoll_cleanup(&nt->np);
592
593 config_item_put(&nt->item);
594}
595
596static struct configfs_group_operations netconsole_subsys_group_ops = {
597 .make_item = make_netconsole_target,
598 .drop_item = drop_netconsole_target,
599};
600
601static struct config_item_type netconsole_subsys_type = {
602 .ct_group_ops = &netconsole_subsys_group_ops,
603 .ct_owner = THIS_MODULE,
604};
605
606/* The netconsole configfs subsystem */
607static struct configfs_subsystem netconsole_subsys = {
608 .su_group = {
609 .cg_item = {
610 .ci_namebuf = "netconsole",
611 .ci_type = &netconsole_subsys_type,
612 },
613 },
614};
615
616#endif /* CONFIG_NETCONSOLE_DYNAMIC */
617
618/* Handle network interface device notifications */
619static int netconsole_netdev_event(struct notifier_block *this,
620 unsigned long event,
621 void *ptr)
622{
623 unsigned long flags;
624 struct netconsole_target *nt;
625 struct net_device *dev = ptr;
626 bool stopped = false;
627
628 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
629 event == NETDEV_RELEASE || event == NETDEV_JOIN))
630 goto done;
631
632 spin_lock_irqsave(&target_list_lock, flags);
633 list_for_each_entry(nt, &target_list, list) {
634 netconsole_target_get(nt);
635 if (nt->np.dev == dev) {
636 switch (event) {
637 case NETDEV_CHANGENAME:
638 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
639 break;
640 case NETDEV_RELEASE:
641 case NETDEV_JOIN:
642 case NETDEV_UNREGISTER:
643 /*
644 * rtnl_lock already held
645 */
646 if (nt->np.dev) {
647 spin_unlock_irqrestore(
648 &target_list_lock,
649 flags);
650 __netpoll_cleanup(&nt->np);
651 spin_lock_irqsave(&target_list_lock,
652 flags);
653 dev_put(nt->np.dev);
654 nt->np.dev = NULL;
655 netconsole_target_put(nt);
656 }
657 nt->enabled = 0;
658 stopped = true;
659 break;
660 }
661 }
662 netconsole_target_put(nt);
663 }
664 spin_unlock_irqrestore(&target_list_lock, flags);
665 if (stopped) {
666 printk(KERN_INFO "netconsole: network logging stopped on "
667 "interface %s as it ", dev->name);
668 switch (event) {
669 case NETDEV_UNREGISTER:
670 printk(KERN_CONT "unregistered\n");
671 break;
672 case NETDEV_RELEASE:
673 printk(KERN_CONT "released slaves\n");
674 break;
675 case NETDEV_JOIN:
676 printk(KERN_CONT "is joining a master device\n");
677 break;
678 }
679 }
680
681done:
682 return NOTIFY_DONE;
683}
684
685static struct notifier_block netconsole_netdev_notifier = {
686 .notifier_call = netconsole_netdev_event,
687};
688
689static void write_msg(struct console *con, const char *msg, unsigned int len)
690{
691 int frag, left;
692 unsigned long flags;
693 struct netconsole_target *nt;
694 const char *tmp;
695
696 /* Avoid taking lock and disabling interrupts unnecessarily */
697 if (list_empty(&target_list))
698 return;
699
700 spin_lock_irqsave(&target_list_lock, flags);
701 list_for_each_entry(nt, &target_list, list) {
702 netconsole_target_get(nt);
703 if (nt->enabled && netif_running(nt->np.dev)) {
704 /*
705 * We nest this inside the for-each-target loop above
706 * so that we're able to get as much logging out to
707 * at least one target if we die inside here, instead
708 * of unnecessarily keeping all targets in lock-step.
709 */
710 tmp = msg;
711 for (left = len; left;) {
712 frag = min(left, MAX_PRINT_CHUNK);
713 netpoll_send_udp(&nt->np, tmp, frag);
714 tmp += frag;
715 left -= frag;
716 }
717 }
718 netconsole_target_put(nt);
719 }
720 spin_unlock_irqrestore(&target_list_lock, flags);
721}
722
723static struct console netconsole = {
724 .name = "netcon",
725 .flags = CON_ENABLED,
726 .write = write_msg,
727};
728
729static int __init init_netconsole(void)
730{
731 int err;
732 struct netconsole_target *nt, *tmp;
733 unsigned long flags;
734 char *target_config;
735 char *input = config;
736
737 if (strnlen(input, MAX_PARAM_LENGTH)) {
738 while ((target_config = strsep(&input, ";"))) {
739 nt = alloc_param_target(target_config);
740 if (IS_ERR(nt)) {
741 err = PTR_ERR(nt);
742 goto fail;
743 }
744 /* Dump existing printks when we register */
745 netconsole.flags |= CON_PRINTBUFFER;
746
747 spin_lock_irqsave(&target_list_lock, flags);
748 list_add(&nt->list, &target_list);
749 spin_unlock_irqrestore(&target_list_lock, flags);
750 }
751 }
752
753 err = register_netdevice_notifier(&netconsole_netdev_notifier);
754 if (err)
755 goto fail;
756
757 err = dynamic_netconsole_init();
758 if (err)
759 goto undonotifier;
760
761 register_console(&netconsole);
762 printk(KERN_INFO "netconsole: network logging started\n");
763
764 return err;
765
766undonotifier:
767 unregister_netdevice_notifier(&netconsole_netdev_notifier);
768
769fail:
770 printk(KERN_ERR "netconsole: cleaning up\n");
771
772 /*
773 * Remove all targets and destroy them (only targets created
774 * from the boot/module option exist here). Skipping the list
775 * lock is safe here, and netpoll_cleanup() will sleep.
776 */
777 list_for_each_entry_safe(nt, tmp, &target_list, list) {
778 list_del(&nt->list);
779 free_param_target(nt);
780 }
781
782 return err;
783}
784
785static void __exit cleanup_netconsole(void)
786{
787 struct netconsole_target *nt, *tmp;
788
789 unregister_console(&netconsole);
790 dynamic_netconsole_exit();
791 unregister_netdevice_notifier(&netconsole_netdev_notifier);
792
793 /*
794 * Targets created via configfs pin references on our module
795 * and would first be rmdir(2)'ed from userspace. We reach
796 * here only when they are already destroyed, and only those
797 * created from the boot/module option are left, so remove and
798 * destroy them. Skipping the list lock is safe here, and
799 * netpoll_cleanup() will sleep.
800 */
801 list_for_each_entry_safe(nt, tmp, &target_list, list) {
802 list_del(&nt->list);
803 free_param_target(nt);
804 }
805}
806
807/*
808 * Use late_initcall to ensure netconsole is
809 * initialized after network device driver if built-in.
810 *
811 * late_initcall() and module_init() are identical if built as module.
812 */
813late_initcall(init_netconsole);
814module_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);