2 * linux/drivers/net/netconsole.c
4 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
6 * This file contains the implementation of an IRQ-safe, crash-safe
7 * kernel console implementation that outputs kernel messages to the
10 * Modification history:
12 * 2001-09-17 started by Ingo Molnar.
13 * 2003-08-11 2.6 port by Matt Mackall
17 * 2003-09-07 rewritten with netpoll api
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)
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.
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.
35 ****************************************************************/
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
40 #include <linux/init.h>
41 #include <linux/module.h>
42 #include <linux/slab.h>
43 #include <linux/console.h>
44 #include <linux/moduleparam.h>
45 #include <linux/kernel.h>
46 #include <linux/string.h>
47 #include <linux/netpoll.h>
48 #include <linux/inet.h>
49 #include <linux/configfs.h>
50 #include <linux/etherdevice.h>
52 MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
53 MODULE_DESCRIPTION("Console driver for network interfaces");
54 MODULE_LICENSE("GPL");
56 #define MAX_PARAM_LENGTH 256
57 #define MAX_PRINT_CHUNK 1000
59 static char config[MAX_PARAM_LENGTH];
60 module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
61 MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
63 static bool oops_only = false;
64 module_param(oops_only, bool, 0600);
65 MODULE_PARM_DESC(oops_only, "Only log oops messages");
68 static int __init option_setup(char *opt)
70 strlcpy(config, opt, MAX_PARAM_LENGTH);
73 __setup("netconsole=", option_setup);
76 /* Linked list of all configured targets */
77 static LIST_HEAD(target_list);
79 /* This needs to be a spinlock because write_msg() cannot sleep */
80 static DEFINE_SPINLOCK(target_list_lock);
83 * struct netconsole_target - Represents a configured netconsole target.
84 * @list: Links this target into the target_list.
85 * @item: Links us into the configfs subsystem hierarchy.
86 * @enabled: On / off knob to enable / disable target.
87 * Visible from userspace (read-write).
88 * We maintain a strict 1:1 correspondence between this and
89 * whether the corresponding netpoll is active or inactive.
90 * Also, other parameters of a target may be modified at
91 * runtime only when it is disabled (enabled == 0).
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)
102 struct netconsole_target {
103 struct list_head list;
104 #ifdef CONFIG_NETCONSOLE_DYNAMIC
105 struct config_item item;
111 #ifdef CONFIG_NETCONSOLE_DYNAMIC
113 static struct configfs_subsystem netconsole_subsys;
114 static DEFINE_MUTEX(dynamic_netconsole_mutex);
116 static int __init dynamic_netconsole_init(void)
118 config_group_init(&netconsole_subsys.su_group);
119 mutex_init(&netconsole_subsys.su_mutex);
120 return configfs_register_subsystem(&netconsole_subsys);
123 static void __exit dynamic_netconsole_exit(void)
125 configfs_unregister_subsystem(&netconsole_subsys);
129 * Targets that were created by parsing the boot/module option string
130 * do not exist in the configfs hierarchy (and have NULL names) and will
131 * never go away, so make these a no-op for them.
133 static void netconsole_target_get(struct netconsole_target *nt)
135 if (config_item_name(&nt->item))
136 config_item_get(&nt->item);
139 static void netconsole_target_put(struct netconsole_target *nt)
141 if (config_item_name(&nt->item))
142 config_item_put(&nt->item);
145 #else /* !CONFIG_NETCONSOLE_DYNAMIC */
147 static int __init dynamic_netconsole_init(void)
152 static void __exit dynamic_netconsole_exit(void)
157 * No danger of targets going away from under us when dynamic
158 * reconfigurability is off.
160 static void netconsole_target_get(struct netconsole_target *nt)
164 static void netconsole_target_put(struct netconsole_target *nt)
168 #endif /* CONFIG_NETCONSOLE_DYNAMIC */
170 /* Allocate new target (from boot/module param) and setup netpoll for it */
171 static struct netconsole_target *alloc_param_target(char *target_config)
174 struct netconsole_target *nt;
177 * Allocate and initialize with defaults.
178 * Note that these targets get their config_item fields zeroed-out.
180 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
184 nt->np.name = "netconsole";
185 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
186 nt->np.local_port = 6665;
187 nt->np.remote_port = 6666;
188 eth_broadcast_addr(nt->np.remote_mac);
190 /* Parse parameters and setup netpoll */
191 err = netpoll_parse_options(&nt->np, target_config);
195 err = netpoll_setup(&nt->np);
208 /* Cleanup netpoll for given target (from boot/module param) and free it */
209 static void free_param_target(struct netconsole_target *nt)
211 netpoll_cleanup(&nt->np);
215 #ifdef CONFIG_NETCONSOLE_DYNAMIC
218 * Our subsystem hierarchy is:
220 * /sys/kernel/config/netconsole/
235 struct netconsole_target_attr {
236 struct configfs_attribute attr;
237 ssize_t (*show)(struct netconsole_target *nt,
239 ssize_t (*store)(struct netconsole_target *nt,
244 static struct netconsole_target *to_target(struct config_item *item)
247 container_of(item, struct netconsole_target, item) :
252 * Attribute operations for netconsole_target.
255 static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
257 return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
260 static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
262 return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
265 static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
267 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
270 static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
272 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
275 static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
278 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
280 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
283 static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
286 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
288 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
291 static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
293 struct net_device *dev = nt->np.dev;
294 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
296 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
299 static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
301 return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
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).
311 static ssize_t store_enabled(struct netconsole_target *nt,
319 err = kstrtoint(buf, 10, &enabled);
322 if (enabled < 0 || enabled > 1)
324 if ((bool)enabled == nt->enabled) {
325 pr_info("network logging has already %s\n",
326 nt->enabled ? "started" : "stopped");
330 if (enabled) { /* true */
332 * Skip netpoll_parse_options() -- all the attributes are
333 * already configured via configfs. Just print them out.
335 netpoll_print_options(&nt->np);
337 err = netpoll_setup(&nt->np);
341 pr_info("netconsole: network logging started\n");
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 == true
347 spin_lock_irqsave(&target_list_lock, flags);
349 spin_unlock_irqrestore(&target_list_lock, flags);
350 netpoll_cleanup(&nt->np);
353 nt->enabled = enabled;
355 return strnlen(buf, count);
358 static ssize_t store_dev_name(struct netconsole_target *nt,
365 pr_err("target (%s) is enabled, disable to update parameters\n",
366 config_item_name(&nt->item));
370 strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
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';
377 return strnlen(buf, count);
380 static ssize_t store_local_port(struct netconsole_target *nt,
387 pr_err("target (%s) is enabled, disable to update parameters\n",
388 config_item_name(&nt->item));
392 rv = kstrtou16(buf, 10, &nt->np.local_port);
395 return strnlen(buf, count);
398 static ssize_t store_remote_port(struct netconsole_target *nt,
405 pr_err("target (%s) is enabled, disable to update parameters\n",
406 config_item_name(&nt->item));
410 rv = kstrtou16(buf, 10, &nt->np.remote_port);
413 return strnlen(buf, count);
416 static ssize_t store_local_ip(struct netconsole_target *nt,
421 pr_err("target (%s) is enabled, disable to update parameters\n",
422 config_item_name(&nt->item));
426 if (strnchr(buf, count, ':')) {
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);
438 nt->np.local_ip.ip = in_aton(buf);
443 return strnlen(buf, count);
446 static ssize_t store_remote_ip(struct netconsole_target *nt,
451 pr_err("target (%s) is enabled, disable to update parameters\n",
452 config_item_name(&nt->item));
456 if (strnchr(buf, count, ':')) {
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);
468 nt->np.remote_ip.ip = in_aton(buf);
473 return strnlen(buf, count);
476 static ssize_t store_remote_mac(struct netconsole_target *nt,
480 u8 remote_mac[ETH_ALEN];
483 pr_err("target (%s) is enabled, disable to update parameters\n",
484 config_item_name(&nt->item));
488 if (!mac_pton(buf, remote_mac))
490 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
492 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
494 return strnlen(buf, count);
498 * Attribute definitions for netconsole_target.
501 #define NETCONSOLE_TARGET_ATTR_RO(_name) \
502 static struct netconsole_target_attr netconsole_target_##_name = \
503 __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
505 #define NETCONSOLE_TARGET_ATTR_RW(_name) \
506 static struct netconsole_target_attr netconsole_target_##_name = \
507 __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
509 NETCONSOLE_TARGET_ATTR_RW(enabled);
510 NETCONSOLE_TARGET_ATTR_RW(dev_name);
511 NETCONSOLE_TARGET_ATTR_RW(local_port);
512 NETCONSOLE_TARGET_ATTR_RW(remote_port);
513 NETCONSOLE_TARGET_ATTR_RW(local_ip);
514 NETCONSOLE_TARGET_ATTR_RW(remote_ip);
515 NETCONSOLE_TARGET_ATTR_RO(local_mac);
516 NETCONSOLE_TARGET_ATTR_RW(remote_mac);
518 static 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,
531 * Item operations and type for netconsole_target.
534 static void netconsole_target_release(struct config_item *item)
536 kfree(to_target(item));
539 static ssize_t netconsole_target_attr_show(struct config_item *item,
540 struct configfs_attribute *attr,
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);
549 ret = na->show(nt, buf);
554 static ssize_t netconsole_target_attr_store(struct config_item *item,
555 struct configfs_attribute *attr,
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);
564 mutex_lock(&dynamic_netconsole_mutex);
566 ret = na->store(nt, buf, count);
567 mutex_unlock(&dynamic_netconsole_mutex);
572 static 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,
578 static 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,
585 * Group operations and type for netconsole_subsys.
588 static struct config_item *make_netconsole_target(struct config_group *group,
592 struct netconsole_target *nt;
595 * Allocate and initialize with defaults.
596 * Target is disabled at creation (!enabled).
598 nt = kzalloc(sizeof(*nt), GFP_KERNEL);
600 return ERR_PTR(-ENOMEM);
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 eth_broadcast_addr(nt->np.remote_mac);
608 /* Initialize the config_item member */
609 config_item_init_type_name(&nt->item, name, &netconsole_target_type);
611 /* Adding, but it is disabled */
612 spin_lock_irqsave(&target_list_lock, flags);
613 list_add(&nt->list, &target_list);
614 spin_unlock_irqrestore(&target_list_lock, flags);
619 static void drop_netconsole_target(struct config_group *group,
620 struct config_item *item)
623 struct netconsole_target *nt = to_target(item);
625 spin_lock_irqsave(&target_list_lock, flags);
627 spin_unlock_irqrestore(&target_list_lock, flags);
630 * The target may have never been enabled, or was manually disabled
631 * before being removed so netpoll may have already been cleaned up.
634 netpoll_cleanup(&nt->np);
636 config_item_put(&nt->item);
639 static struct configfs_group_operations netconsole_subsys_group_ops = {
640 .make_item = make_netconsole_target,
641 .drop_item = drop_netconsole_target,
644 static struct config_item_type netconsole_subsys_type = {
645 .ct_group_ops = &netconsole_subsys_group_ops,
646 .ct_owner = THIS_MODULE,
649 /* The netconsole configfs subsystem */
650 static struct configfs_subsystem netconsole_subsys = {
653 .ci_namebuf = "netconsole",
654 .ci_type = &netconsole_subsys_type,
659 #endif /* CONFIG_NETCONSOLE_DYNAMIC */
661 /* Handle network interface device notifications */
662 static int netconsole_netdev_event(struct notifier_block *this,
663 unsigned long event, void *ptr)
666 struct netconsole_target *nt;
667 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
668 bool stopped = false;
670 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
671 event == NETDEV_RELEASE || event == NETDEV_JOIN))
674 spin_lock_irqsave(&target_list_lock, flags);
676 list_for_each_entry(nt, &target_list, list) {
677 netconsole_target_get(nt);
678 if (nt->np.dev == dev) {
680 case NETDEV_CHANGENAME:
681 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
685 case NETDEV_UNREGISTER:
686 /* rtnl_lock already held
687 * we might sleep in __netpoll_cleanup()
689 spin_unlock_irqrestore(&target_list_lock, flags);
691 __netpoll_cleanup(&nt->np);
693 spin_lock_irqsave(&target_list_lock, flags);
698 netconsole_target_put(nt);
702 netconsole_target_put(nt);
704 spin_unlock_irqrestore(&target_list_lock, flags);
706 const char *msg = "had an event";
708 case NETDEV_UNREGISTER:
709 msg = "unregistered";
712 msg = "released slaves";
715 msg = "is joining a master device";
718 pr_info("network logging stopped on interface %s as it %s\n",
726 static struct notifier_block netconsole_netdev_notifier = {
727 .notifier_call = netconsole_netdev_event,
730 static void write_msg(struct console *con, const char *msg, unsigned int len)
734 struct netconsole_target *nt;
737 if (oops_only && !oops_in_progress)
739 /* Avoid taking lock and disabling interrupts unnecessarily */
740 if (list_empty(&target_list))
743 spin_lock_irqsave(&target_list_lock, flags);
744 list_for_each_entry(nt, &target_list, list) {
745 if (nt->enabled && netif_running(nt->np.dev)) {
747 * We nest this inside the for-each-target loop above
748 * so that we're able to get as much logging out to
749 * at least one target if we die inside here, instead
750 * of unnecessarily keeping all targets in lock-step.
753 for (left = len; left;) {
754 frag = min(left, MAX_PRINT_CHUNK);
755 netpoll_send_udp(&nt->np, tmp, frag);
761 spin_unlock_irqrestore(&target_list_lock, flags);
764 static struct console netconsole = {
766 .flags = CON_ENABLED,
770 static int __init init_netconsole(void)
773 struct netconsole_target *nt, *tmp;
776 char *input = config;
778 if (strnlen(input, MAX_PARAM_LENGTH)) {
779 while ((target_config = strsep(&input, ";"))) {
780 nt = alloc_param_target(target_config);
785 /* Dump existing printks when we register */
786 netconsole.flags |= CON_PRINTBUFFER;
788 spin_lock_irqsave(&target_list_lock, flags);
789 list_add(&nt->list, &target_list);
790 spin_unlock_irqrestore(&target_list_lock, flags);
794 err = register_netdevice_notifier(&netconsole_netdev_notifier);
798 err = dynamic_netconsole_init();
802 register_console(&netconsole);
803 pr_info("network logging started\n");
808 unregister_netdevice_notifier(&netconsole_netdev_notifier);
811 pr_err("cleaning up\n");
814 * Remove all targets and destroy them (only targets created
815 * from the boot/module option exist here). Skipping the list
816 * lock is safe here, and netpoll_cleanup() will sleep.
818 list_for_each_entry_safe(nt, tmp, &target_list, list) {
820 free_param_target(nt);
826 static void __exit cleanup_netconsole(void)
828 struct netconsole_target *nt, *tmp;
830 unregister_console(&netconsole);
831 dynamic_netconsole_exit();
832 unregister_netdevice_notifier(&netconsole_netdev_notifier);
835 * Targets created via configfs pin references on our module
836 * and would first be rmdir(2)'ed from userspace. We reach
837 * here only when they are already destroyed, and only those
838 * created from the boot/module option are left, so remove and
839 * destroy them. Skipping the list lock is safe here, and
840 * netpoll_cleanup() will sleep.
842 list_for_each_entry_safe(nt, tmp, &target_list, list) {
844 free_param_target(nt);
849 * Use late_initcall to ensure netconsole is
850 * initialized after network device driver if built-in.
852 * late_initcall() and module_init() are identical if built as module.
854 late_initcall(init_netconsole);
855 module_exit(cleanup_netconsole);