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	strlcpy(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	strlcpy(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 && !(netconsole_ext.flags & CON_ENABLED)) {
336			netconsole_ext.flags |= CON_ENABLED;
337			register_console(&netconsole_ext);
338		}
339
 
 
 
340		/*
341		 * Skip netpoll_parse_options() -- all the attributes are
342		 * already configured via configfs. Just print them out.
343		 */
344		netpoll_print_options(&nt->np);
345
346		err = netpoll_setup(&nt->np);
347		if (err)
348			goto out_unlock;
349
350		pr_info("network logging started\n");
351	} else {	/* false */
352		/* We need to disable the netconsole before cleaning it up
353		 * otherwise we might end up in write_msg() with
354		 * nt->np.dev == NULL and nt->enabled == true
355		 */
356		spin_lock_irqsave(&target_list_lock, flags);
357		nt->enabled = false;
358		spin_unlock_irqrestore(&target_list_lock, flags);
359		netpoll_cleanup(&nt->np);
360	}
361
362	nt->enabled = enabled;
363
364	mutex_unlock(&dynamic_netconsole_mutex);
365	return strnlen(buf, count);
366out_unlock:
367	mutex_unlock(&dynamic_netconsole_mutex);
368	return err;
369}
370
371static ssize_t extended_store(struct config_item *item, const char *buf,
372		size_t count)
373{
374	struct netconsole_target *nt = to_target(item);
375	int extended;
376	int err;
377
378	mutex_lock(&dynamic_netconsole_mutex);
379	if (nt->enabled) {
380		pr_err("target (%s) is enabled, disable to update parameters\n",
381		       config_item_name(&nt->item));
382		err = -EINVAL;
383		goto out_unlock;
384	}
385
386	err = kstrtoint(buf, 10, &extended);
387	if (err < 0)
388		goto out_unlock;
389	if (extended < 0 || extended > 1) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
390		err = -EINVAL;
391		goto out_unlock;
392	}
393
 
 
 
 
394	nt->extended = extended;
395
396	mutex_unlock(&dynamic_netconsole_mutex);
397	return strnlen(buf, count);
398out_unlock:
399	mutex_unlock(&dynamic_netconsole_mutex);
400	return err;
401}
402
403static ssize_t dev_name_store(struct config_item *item, const char *buf,
404		size_t count)
405{
406	struct netconsole_target *nt = to_target(item);
407	size_t len;
408
409	mutex_lock(&dynamic_netconsole_mutex);
410	if (nt->enabled) {
411		pr_err("target (%s) is enabled, disable to update parameters\n",
412		       config_item_name(&nt->item));
413		mutex_unlock(&dynamic_netconsole_mutex);
414		return -EINVAL;
415	}
416
417	strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
418
419	/* Get rid of possible trailing newline from echo(1) */
420	len = strnlen(nt->np.dev_name, IFNAMSIZ);
421	if (nt->np.dev_name[len - 1] == '\n')
422		nt->np.dev_name[len - 1] = '\0';
423
424	mutex_unlock(&dynamic_netconsole_mutex);
425	return strnlen(buf, count);
426}
427
428static ssize_t local_port_store(struct config_item *item, const char *buf,
429		size_t count)
430{
431	struct netconsole_target *nt = to_target(item);
432	int rv = -EINVAL;
433
434	mutex_lock(&dynamic_netconsole_mutex);
435	if (nt->enabled) {
436		pr_err("target (%s) is enabled, disable to update parameters\n",
437		       config_item_name(&nt->item));
438		goto out_unlock;
439	}
440
441	rv = kstrtou16(buf, 10, &nt->np.local_port);
442	if (rv < 0)
443		goto out_unlock;
444	mutex_unlock(&dynamic_netconsole_mutex);
445	return strnlen(buf, count);
446out_unlock:
447	mutex_unlock(&dynamic_netconsole_mutex);
448	return rv;
449}
450
451static ssize_t remote_port_store(struct config_item *item,
452		const char *buf, size_t count)
453{
454	struct netconsole_target *nt = to_target(item);
455	int rv = -EINVAL;
456
457	mutex_lock(&dynamic_netconsole_mutex);
458	if (nt->enabled) {
459		pr_err("target (%s) is enabled, disable to update parameters\n",
460		       config_item_name(&nt->item));
461		goto out_unlock;
462	}
463
464	rv = kstrtou16(buf, 10, &nt->np.remote_port);
465	if (rv < 0)
466		goto out_unlock;
467	mutex_unlock(&dynamic_netconsole_mutex);
468	return strnlen(buf, count);
469out_unlock:
470	mutex_unlock(&dynamic_netconsole_mutex);
471	return rv;
472}
473
474static ssize_t local_ip_store(struct config_item *item, const char *buf,
475		size_t count)
476{
477	struct netconsole_target *nt = to_target(item);
478
479	mutex_lock(&dynamic_netconsole_mutex);
480	if (nt->enabled) {
481		pr_err("target (%s) is enabled, disable to update parameters\n",
482		       config_item_name(&nt->item));
483		goto out_unlock;
484	}
485
486	if (strnchr(buf, count, ':')) {
487		const char *end;
 
488		if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
489			if (*end && *end != '\n') {
490				pr_err("invalid IPv6 address at: <%c>\n", *end);
491				goto out_unlock;
492			}
493			nt->np.ipv6 = true;
494		} else
495			goto out_unlock;
496	} else {
497		if (!nt->np.ipv6) {
498			nt->np.local_ip.ip = in_aton(buf);
499		} else
500			goto out_unlock;
501	}
502
503	mutex_unlock(&dynamic_netconsole_mutex);
504	return strnlen(buf, count);
505out_unlock:
506	mutex_unlock(&dynamic_netconsole_mutex);
507	return -EINVAL;
508}
509
510static ssize_t remote_ip_store(struct config_item *item, const char *buf,
511	       size_t count)
512{
513	struct netconsole_target *nt = to_target(item);
514
515	mutex_lock(&dynamic_netconsole_mutex);
516	if (nt->enabled) {
517		pr_err("target (%s) is enabled, disable to update parameters\n",
518		       config_item_name(&nt->item));
519		goto out_unlock;
520	}
521
522	if (strnchr(buf, count, ':')) {
523		const char *end;
 
524		if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
525			if (*end && *end != '\n') {
526				pr_err("invalid IPv6 address at: <%c>\n", *end);
527				goto out_unlock;
528			}
529			nt->np.ipv6 = true;
530		} else
531			goto out_unlock;
532	} else {
533		if (!nt->np.ipv6) {
534			nt->np.remote_ip.ip = in_aton(buf);
535		} else
536			goto out_unlock;
537	}
538
539	mutex_unlock(&dynamic_netconsole_mutex);
540	return strnlen(buf, count);
541out_unlock:
542	mutex_unlock(&dynamic_netconsole_mutex);
543	return -EINVAL;
544}
545
546static ssize_t remote_mac_store(struct config_item *item, const char *buf,
547		size_t count)
548{
549	struct netconsole_target *nt = to_target(item);
550	u8 remote_mac[ETH_ALEN];
551
552	mutex_lock(&dynamic_netconsole_mutex);
553	if (nt->enabled) {
554		pr_err("target (%s) is enabled, disable to update parameters\n",
555		       config_item_name(&nt->item));
556		goto out_unlock;
557	}
558
559	if (!mac_pton(buf, remote_mac))
560		goto out_unlock;
561	if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
562		goto out_unlock;
563	memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
564
565	mutex_unlock(&dynamic_netconsole_mutex);
566	return strnlen(buf, count);
567out_unlock:
568	mutex_unlock(&dynamic_netconsole_mutex);
569	return -EINVAL;
570}
571
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
572CONFIGFS_ATTR(, enabled);
573CONFIGFS_ATTR(, extended);
574CONFIGFS_ATTR(, dev_name);
575CONFIGFS_ATTR(, local_port);
576CONFIGFS_ATTR(, remote_port);
577CONFIGFS_ATTR(, local_ip);
578CONFIGFS_ATTR(, remote_ip);
579CONFIGFS_ATTR_RO(, local_mac);
580CONFIGFS_ATTR(, remote_mac);
 
581
582static struct configfs_attribute *netconsole_target_attrs[] = {
583	&attr_enabled,
584	&attr_extended,
 
585	&attr_dev_name,
586	&attr_local_port,
587	&attr_remote_port,
588	&attr_local_ip,
589	&attr_remote_ip,
590	&attr_local_mac,
591	&attr_remote_mac,
592	NULL,
593};
594
595/*
596 * Item operations and type for netconsole_target.
597 */
598
599static void netconsole_target_release(struct config_item *item)
600{
601	kfree(to_target(item));
602}
603
604static struct configfs_item_operations netconsole_target_item_ops = {
605	.release		= netconsole_target_release,
606};
607
608static const struct config_item_type netconsole_target_type = {
609	.ct_attrs		= netconsole_target_attrs,
610	.ct_item_ops		= &netconsole_target_item_ops,
611	.ct_owner		= THIS_MODULE,
612};
613
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
614/*
615 * Group operations and type for netconsole_subsys.
616 */
617
618static struct config_item *make_netconsole_target(struct config_group *group,
619						  const char *name)
620{
621	unsigned long flags;
622	struct netconsole_target *nt;
 
623
624	/*
625	 * Allocate and initialize with defaults.
626	 * Target is disabled at creation (!enabled).
627	 */
628	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 
 
 
 
 
 
 
 
 
629	if (!nt)
630		return ERR_PTR(-ENOMEM);
631
632	nt->np.name = "netconsole";
633	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
634	nt->np.local_port = 6665;
635	nt->np.remote_port = 6666;
636	eth_broadcast_addr(nt->np.remote_mac);
637
638	/* Initialize the config_item member */
639	config_item_init_type_name(&nt->item, name, &netconsole_target_type);
640
641	/* Adding, but it is disabled */
642	spin_lock_irqsave(&target_list_lock, flags);
643	list_add(&nt->list, &target_list);
644	spin_unlock_irqrestore(&target_list_lock, flags);
645
646	return &nt->item;
647}
648
649static void drop_netconsole_target(struct config_group *group,
650				   struct config_item *item)
651{
652	unsigned long flags;
653	struct netconsole_target *nt = to_target(item);
654
655	spin_lock_irqsave(&target_list_lock, flags);
656	list_del(&nt->list);
657	spin_unlock_irqrestore(&target_list_lock, flags);
658
659	/*
660	 * The target may have never been enabled, or was manually disabled
661	 * before being removed so netpoll may have already been cleaned up.
662	 */
663	if (nt->enabled)
664		netpoll_cleanup(&nt->np);
665
666	config_item_put(&nt->item);
667}
668
669static struct configfs_group_operations netconsole_subsys_group_ops = {
670	.make_item	= make_netconsole_target,
671	.drop_item	= drop_netconsole_target,
672};
673
674static const struct config_item_type netconsole_subsys_type = {
675	.ct_group_ops	= &netconsole_subsys_group_ops,
676	.ct_owner	= THIS_MODULE,
677};
678
679/* The netconsole configfs subsystem */
680static struct configfs_subsystem netconsole_subsys = {
681	.su_group	= {
682		.cg_item	= {
683			.ci_namebuf	= "netconsole",
684			.ci_type	= &netconsole_subsys_type,
685		},
686	},
687};
688
 
 
 
 
 
 
 
 
 
 
689#endif	/* CONFIG_NETCONSOLE_DYNAMIC */
690
691/* Handle network interface device notifications */
692static int netconsole_netdev_event(struct notifier_block *this,
693				   unsigned long event, void *ptr)
694{
695	unsigned long flags;
696	struct netconsole_target *nt;
697	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
698	bool stopped = false;
699
700	if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
701	      event == NETDEV_RELEASE || event == NETDEV_JOIN))
702		goto done;
703
704	spin_lock_irqsave(&target_list_lock, flags);
705restart:
706	list_for_each_entry(nt, &target_list, list) {
707		netconsole_target_get(nt);
708		if (nt->np.dev == dev) {
709			switch (event) {
710			case NETDEV_CHANGENAME:
711				strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
712				break;
713			case NETDEV_RELEASE:
714			case NETDEV_JOIN:
715			case NETDEV_UNREGISTER:
716				/* rtnl_lock already held
717				 * we might sleep in __netpoll_cleanup()
718				 */
719				spin_unlock_irqrestore(&target_list_lock, flags);
720
721				__netpoll_cleanup(&nt->np);
722
723				spin_lock_irqsave(&target_list_lock, flags);
724				dev_put(nt->np.dev);
725				nt->np.dev = NULL;
726				nt->enabled = false;
727				stopped = true;
728				netconsole_target_put(nt);
729				goto restart;
730			}
731		}
732		netconsole_target_put(nt);
733	}
734	spin_unlock_irqrestore(&target_list_lock, flags);
735	if (stopped) {
736		const char *msg = "had an event";
 
737		switch (event) {
738		case NETDEV_UNREGISTER:
739			msg = "unregistered";
740			break;
741		case NETDEV_RELEASE:
742			msg = "released slaves";
743			break;
744		case NETDEV_JOIN:
745			msg = "is joining a master device";
746			break;
747		}
748		pr_info("network logging stopped on interface %s as it %s\n",
749			dev->name, msg);
750	}
751
752done:
753	return NOTIFY_DONE;
754}
755
756static struct notifier_block netconsole_netdev_notifier = {
757	.notifier_call  = netconsole_netdev_event,
758};
759
760/**
761 * send_ext_msg_udp - send extended log message to target
762 * @nt: target to send message to
763 * @msg: extended log message to send
764 * @msg_len: length of message
765 *
766 * Transfer extended log @msg to @nt.  If @msg is longer than
767 * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
768 * ncfrag header field added to identify them.
769 */
770static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
771			     int msg_len)
772{
773	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
774	const char *header, *body;
775	int offset = 0;
776	int header_len, body_len;
 
 
 
 
 
 
 
 
 
 
777
778	if (msg_len <= MAX_PRINT_CHUNK) {
779		netpoll_send_udp(&nt->np, msg, msg_len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
780		return;
781	}
782
783	/* need to insert extra header fields, detect header and body */
784	header = msg;
785	body = memchr(msg, ';', msg_len);
786	if (WARN_ON_ONCE(!body))
787		return;
788
789	header_len = body - header;
790	body_len = msg_len - header_len - 1;
791	body++;
792
793	/*
794	 * Transfer multiple chunks with the following extra header.
795	 * "ncfrag=<byte-offset>/<total-bytes>"
796	 */
797	memcpy(buf, header, header_len);
 
 
 
798
799	while (offset < body_len) {
800		int this_header = header_len;
801		int this_chunk;
 
802
803		this_header += scnprintf(buf + this_header,
804					 sizeof(buf) - this_header,
805					 ",ncfrag=%d/%d;", offset, body_len);
806
807		this_chunk = min(body_len - offset,
808				 MAX_PRINT_CHUNK - this_header);
809		if (WARN_ON_ONCE(this_chunk <= 0))
810			return;
811
812		memcpy(buf + this_header, body + offset, this_chunk);
813
814		netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
815
816		offset += this_chunk;
 
817	}
818}
819
820static void write_ext_msg(struct console *con, const char *msg,
821			  unsigned int len)
822{
823	struct netconsole_target *nt;
824	unsigned long flags;
825
826	if ((oops_only && !oops_in_progress) || list_empty(&target_list))
827		return;
828
829	spin_lock_irqsave(&target_list_lock, flags);
830	list_for_each_entry(nt, &target_list, list)
831		if (nt->extended && nt->enabled && netif_running(nt->np.dev))
832			send_ext_msg_udp(nt, msg, len);
833	spin_unlock_irqrestore(&target_list_lock, flags);
834}
835
836static void write_msg(struct console *con, const char *msg, unsigned int len)
837{
838	int frag, left;
839	unsigned long flags;
840	struct netconsole_target *nt;
841	const char *tmp;
842
843	if (oops_only && !oops_in_progress)
844		return;
845	/* Avoid taking lock and disabling interrupts unnecessarily */
846	if (list_empty(&target_list))
847		return;
848
849	spin_lock_irqsave(&target_list_lock, flags);
850	list_for_each_entry(nt, &target_list, list) {
851		if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
852			/*
853			 * We nest this inside the for-each-target loop above
854			 * so that we're able to get as much logging out to
855			 * at least one target if we die inside here, instead
856			 * of unnecessarily keeping all targets in lock-step.
857			 */
858			tmp = msg;
859			for (left = len; left;) {
860				frag = min(left, MAX_PRINT_CHUNK);
861				netpoll_send_udp(&nt->np, tmp, frag);
862				tmp += frag;
863				left -= frag;
864			}
865		}
866	}
867	spin_unlock_irqrestore(&target_list_lock, flags);
868}
869
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
870static struct console netconsole_ext = {
871	.name	= "netcon_ext",
872	.flags	= CON_EXTENDED,	/* starts disabled, registered on first use */
873	.write	= write_ext_msg,
874};
875
876static struct console netconsole = {
877	.name	= "netcon",
878	.flags	= CON_ENABLED,
879	.write	= write_msg,
880};
881
882static int __init init_netconsole(void)
883{
884	int err;
885	struct netconsole_target *nt, *tmp;
 
 
886	unsigned long flags;
887	char *target_config;
888	char *input = config;
889
890	if (strnlen(input, MAX_PARAM_LENGTH)) {
891		while ((target_config = strsep(&input, ";"))) {
892			nt = alloc_param_target(target_config);
893			if (IS_ERR(nt)) {
894				err = PTR_ERR(nt);
895				goto fail;
896			}
897			/* Dump existing printks when we register */
898			if (nt->extended)
899				netconsole_ext.flags |= CON_PRINTBUFFER |
900							CON_ENABLED;
901			else
902				netconsole.flags |= CON_PRINTBUFFER;
 
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 (netconsole_ext.flags & CON_ENABLED)
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	unregister_console(&netconsole_ext);
 
949	unregister_console(&netconsole);
950	dynamic_netconsole_exit();
951	unregister_netdevice_notifier(&netconsole_netdev_notifier);
952
953	/*
954	 * Targets created via configfs pin references on our module
955	 * and would first be rmdir(2)'ed from userspace. We reach
956	 * here only when they are already destroyed, and only those
957	 * created from the boot/module option are left, so remove and
958	 * destroy them. Skipping the list lock is safe here, and
959	 * netpoll_cleanup() will sleep.
960	 */
961	list_for_each_entry_safe(nt, tmp, &target_list, list) {
962		list_del(&nt->list);
963		free_param_target(nt);
964	}
965}
966
967/*
968 * Use late_initcall to ensure netconsole is
969 * initialized after network device driver if built-in.
970 *
971 * late_initcall() and module_init() are identical if built as module.
972 */
973late_initcall(init_netconsole);
974module_exit(cleanup_netconsole);