// SPDX-License-Identifier: GPL-2.0-or-later /* * linux/drivers/net/netconsole.c * * Copyright (C) 2001 Ingo Molnar * * This file contains the implementation of an IRQ-safe, crash-safe * kernel console implementation that outputs kernel messages to the * network. * * Modification history: * * 2001-09-17 started by Ingo Molnar. * 2003-08-11 2.6 port by Matt Mackall * simplified options * generic card hooks * works non-modular * 2003-09-07 rewritten with netpoll api */ /**************************************************************** * ****************************************************************/ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include MODULE_AUTHOR("Maintainer: Matt Mackall "); MODULE_DESCRIPTION("Console driver for network interfaces"); MODULE_LICENSE("GPL"); #define MAX_PARAM_LENGTH 256 #define MAX_PRINT_CHUNK 1000 static char config[MAX_PARAM_LENGTH]; module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0); MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@/[tgt-macaddr]"); static bool oops_only = false; module_param(oops_only, bool, 0600); MODULE_PARM_DESC(oops_only, "Only log oops messages"); #ifndef MODULE static int __init option_setup(char *opt) { strlcpy(config, opt, MAX_PARAM_LENGTH); return 1; } __setup("netconsole=", option_setup); #endif /* MODULE */ /* Linked list of all configured targets */ static LIST_HEAD(target_list); /* This needs to be a spinlock because write_msg() cannot sleep */ static DEFINE_SPINLOCK(target_list_lock); /* * Console driver for extended netconsoles. Registered on the first use to * avoid unnecessarily enabling ext message formatting. */ static struct console netconsole_ext; /** * struct netconsole_target - Represents a configured netconsole target. * @list: Links this target into the target_list. * @item: Links us into the configfs subsystem hierarchy. * @enabled: On / off knob to enable / disable target. * Visible from userspace (read-write). * We maintain a strict 1:1 correspondence between this and * whether the corresponding netpoll is active or inactive. * Also, other parameters of a target may be modified at * runtime only when it is disabled (enabled == 0). * @extended: Denotes whether console is extended or not. * @np: The netpoll structure for this target. * Contains the other userspace visible parameters: * dev_name (read-write) * local_port (read-write) * remote_port (read-write) * local_ip (read-write) * remote_ip (read-write) * local_mac (read-only) * remote_mac (read-write) */ struct netconsole_target { struct list_head list; #ifdef CONFIG_NETCONSOLE_DYNAMIC struct config_item item; #endif bool enabled; bool extended; struct netpoll np; }; #ifdef CONFIG_NETCONSOLE_DYNAMIC static struct configfs_subsystem netconsole_subsys; static DEFINE_MUTEX(dynamic_netconsole_mutex); static int __init dynamic_netconsole_init(void) { config_group_init(&netconsole_subsys.su_group); mutex_init(&netconsole_subsys.su_mutex); return configfs_register_subsystem(&netconsole_subsys); } static void __exit dynamic_netconsole_exit(void) { configfs_unregister_subsystem(&netconsole_subsys); } /* * Targets that were created by parsing the boot/module option string * do not exist in the configfs hierarchy (and have NULL names) and will * never go away, so make these a no-op for them. */ static void netconsole_target_get(struct netconsole_target *nt) { if (config_item_name(&nt->item)) config_item_get(&nt->item); } static void netconsole_target_put(struct netconsole_target *nt) { if (config_item_name(&nt->item)) config_item_put(&nt->item); } #else /* !CONFIG_NETCONSOLE_DYNAMIC */ static int __init dynamic_netconsole_init(void) { return 0; } static void __exit dynamic_netconsole_exit(void) { } /* * No danger of targets going away from under us when dynamic * reconfigurability is off. */ static void netconsole_target_get(struct netconsole_target *nt) { } static void netconsole_target_put(struct netconsole_target *nt) { } #endif /* CONFIG_NETCONSOLE_DYNAMIC */ /* Allocate new target (from boot/module param) and setup netpoll for it */ static struct netconsole_target *alloc_param_target(char *target_config) { int err = -ENOMEM; struct netconsole_target *nt; /* * Allocate and initialize with defaults. * Note that these targets get their config_item fields zeroed-out. */ nt = kzalloc(sizeof(*nt), GFP_KERNEL); if (!nt) goto fail; nt->np.name = "netconsole"; strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ); nt->np.local_port = 6665; nt->np.remote_port = 6666; eth_broadcast_addr(nt->np.remote_mac); if (*target_config == '+') { nt->extended = true; target_config++; } /* Parse parameters and setup netpoll */ err = netpoll_parse_options(&nt->np, target_config); if (err) goto fail; err = netpoll_setup(&nt->np); if (err) goto fail; nt->enabled = true; return nt; fail: kfree(nt); return ERR_PTR(err); } /* Cleanup netpoll for given target (from boot/module param) and free it */ static void free_param_target(struct netconsole_target *nt) { netpoll_cleanup(&nt->np); kfree(nt); } #ifdef CONFIG_NETCONSOLE_DYNAMIC /* * Our subsystem hierarchy is: * * /sys/kernel/config/netconsole/ * | * / * | enabled * | dev_name * | local_port * | remote_port * | local_ip * | remote_ip * | local_mac * | remote_mac * | * /... */ static struct netconsole_target *to_target(struct config_item *item) { return item ? container_of(item, struct netconsole_target, item) : NULL; } /* * Attribute operations for netconsole_target. */ static ssize_t enabled_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->enabled); } static ssize_t extended_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->extended); } static ssize_t dev_name_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%s\n", to_target(item)->np.dev_name); } static ssize_t local_port_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.local_port); } static ssize_t remote_port_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->np.remote_port); } static ssize_t local_ip_show(struct config_item *item, char *buf) { struct netconsole_target *nt = to_target(item); if (nt->np.ipv6) return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6); else return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip); } static ssize_t remote_ip_show(struct config_item *item, char *buf) { struct netconsole_target *nt = to_target(item); if (nt->np.ipv6) return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6); else return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip); } static ssize_t local_mac_show(struct config_item *item, char *buf) { struct net_device *dev = to_target(item)->np.dev; static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast); } static ssize_t remote_mac_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%pM\n", to_target(item)->np.remote_mac); } /* * This one is special -- targets created through the configfs interface * are not enabled (and the corresponding netpoll activated) by default. * The user is expected to set the desired parameters first (which * would enable him to dynamically add new netpoll targets for new * network interfaces as and when they come up). */ static ssize_t enabled_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); unsigned long flags; int enabled; int err; mutex_lock(&dynamic_netconsole_mutex); err = kstrtoint(buf, 10, &enabled); if (err < 0) goto out_unlock; err = -EINVAL; if (enabled < 0 || enabled > 1) goto out_unlock; if ((bool)enabled == nt->enabled) { pr_info("network logging has already %s\n", nt->enabled ? "started" : "stopped"); goto out_unlock; } if (enabled) { /* true */ if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) { netconsole_ext.flags |= CON_ENABLED; register_console(&netconsole_ext); } /* * Skip netpoll_parse_options() -- all the attributes are * already configured via configfs. Just print them out. */ netpoll_print_options(&nt->np); err = netpoll_setup(&nt->np); if (err) goto out_unlock; pr_info("network logging started\n"); } else { /* false */ /* We need to disable the netconsole before cleaning it up * otherwise we might end up in write_msg() with * nt->np.dev == NULL and nt->enabled == true */ spin_lock_irqsave(&target_list_lock, flags); nt->enabled = false; spin_unlock_irqrestore(&target_list_lock, flags); netpoll_cleanup(&nt->np); } nt->enabled = enabled; mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return err; } static ssize_t extended_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); int extended; int err; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); err = -EINVAL; goto out_unlock; } err = kstrtoint(buf, 10, &extended); if (err < 0) goto out_unlock; if (extended < 0 || extended > 1) { err = -EINVAL; goto out_unlock; } nt->extended = extended; mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return err; } static ssize_t dev_name_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); size_t len; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); mutex_unlock(&dynamic_netconsole_mutex); return -EINVAL; } strlcpy(nt->np.dev_name, buf, IFNAMSIZ); /* Get rid of possible trailing newline from echo(1) */ len = strnlen(nt->np.dev_name, IFNAMSIZ); if (nt->np.dev_name[len - 1] == '\n') nt->np.dev_name[len - 1] = '\0'; mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); } static ssize_t local_port_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); int rv = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); goto out_unlock; } rv = kstrtou16(buf, 10, &nt->np.local_port); if (rv < 0) goto out_unlock; mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return rv; } static ssize_t remote_port_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); int rv = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); goto out_unlock; } rv = kstrtou16(buf, 10, &nt->np.remote_port); if (rv < 0) goto out_unlock; mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return rv; } static ssize_t local_ip_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); goto out_unlock; } if (strnchr(buf, count, ':')) { const char *end; if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) { if (*end && *end != '\n') { pr_err("invalid IPv6 address at: <%c>\n", *end); goto out_unlock; } nt->np.ipv6 = true; } else goto out_unlock; } else { if (!nt->np.ipv6) { nt->np.local_ip.ip = in_aton(buf); } else goto out_unlock; } mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return -EINVAL; } static ssize_t remote_ip_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); goto out_unlock; } if (strnchr(buf, count, ':')) { const char *end; if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) { if (*end && *end != '\n') { pr_err("invalid IPv6 address at: <%c>\n", *end); goto out_unlock; } nt->np.ipv6 = true; } else goto out_unlock; } else { if (!nt->np.ipv6) { nt->np.remote_ip.ip = in_aton(buf); } else goto out_unlock; } mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return -EINVAL; } static ssize_t remote_mac_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); u8 remote_mac[ETH_ALEN]; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->item)); goto out_unlock; } if (!mac_pton(buf, remote_mac)) goto out_unlock; if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n') goto out_unlock; memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN); mutex_unlock(&dynamic_netconsole_mutex); return strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return -EINVAL; } CONFIGFS_ATTR(, enabled); CONFIGFS_ATTR(, extended); CONFIGFS_ATTR(, dev_name); CONFIGFS_ATTR(, local_port); CONFIGFS_ATTR(, remote_port); CONFIGFS_ATTR(, local_ip); CONFIGFS_ATTR(, remote_ip); CONFIGFS_ATTR_RO(, local_mac); CONFIGFS_ATTR(, remote_mac); static struct configfs_attribute *netconsole_target_attrs[] = { &attr_enabled, &attr_extended, &attr_dev_name, &attr_local_port, &attr_remote_port, &attr_local_ip, &attr_remote_ip, &attr_local_mac, &attr_remote_mac, NULL, }; /* * Item operations and type for netconsole_target. */ static void netconsole_target_release(struct config_item *item) { kfree(to_target(item)); } static struct configfs_item_operations netconsole_target_item_ops = { .release = netconsole_target_release, }; static const struct config_item_type netconsole_target_type = { .ct_attrs = netconsole_target_attrs, .ct_item_ops = &netconsole_target_item_ops, .ct_owner = THIS_MODULE, }; /* * Group operations and type for netconsole_subsys. */ static struct config_item *make_netconsole_target(struct config_group *group, const char *name) { unsigned long flags; struct netconsole_target *nt; /* * Allocate and initialize with defaults. * Target is disabled at creation (!enabled). */ nt = kzalloc(sizeof(*nt), GFP_KERNEL); if (!nt) return ERR_PTR(-ENOMEM); nt->np.name = "netconsole"; strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ); nt->np.local_port = 6665; nt->np.remote_port = 6666; eth_broadcast_addr(nt->np.remote_mac); /* Initialize the config_item member */ config_item_init_type_name(&nt->item, name, &netconsole_target_type); /* Adding, but it is disabled */ spin_lock_irqsave(&target_list_lock, flags); list_add(&nt->list, &target_list); spin_unlock_irqrestore(&target_list_lock, flags); return &nt->item; } static void drop_netconsole_target(struct config_group *group, struct config_item *item) { unsigned long flags; struct netconsole_target *nt = to_target(item); spin_lock_irqsave(&target_list_lock, flags); list_del(&nt->list); spin_unlock_irqrestore(&target_list_lock, flags); /* * The target may have never been enabled, or was manually disabled * before being removed so netpoll may have already been cleaned up. */ if (nt->enabled) netpoll_cleanup(&nt->np); config_item_put(&nt->item); } static struct configfs_group_operations netconsole_subsys_group_ops = { .make_item = make_netconsole_target, .drop_item = drop_netconsole_target, }; static const struct config_item_type netconsole_subsys_type = { .ct_group_ops = &netconsole_subsys_group_ops, .ct_owner = THIS_MODULE, }; /* The netconsole configfs subsystem */ static struct configfs_subsystem netconsole_subsys = { .su_group = { .cg_item = { .ci_namebuf = "netconsole", .ci_type = &netconsole_subsys_type, }, }, }; #endif /* CONFIG_NETCONSOLE_DYNAMIC */ /* Handle network interface device notifications */ static int netconsole_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) { unsigned long flags; struct netconsole_target *nt; struct net_device *dev = netdev_notifier_info_to_dev(ptr); bool stopped = false; if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER || event == NETDEV_RELEASE || event == NETDEV_JOIN)) goto done; spin_lock_irqsave(&target_list_lock, flags); restart: list_for_each_entry(nt, &target_list, list) { netconsole_target_get(nt); if (nt->np.dev == dev) { switch (event) { case NETDEV_CHANGENAME: strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ); break; case NETDEV_RELEASE: case NETDEV_JOIN: case NETDEV_UNREGISTER: /* rtnl_lock already held * we might sleep in __netpoll_cleanup() */ spin_unlock_irqrestore(&target_list_lock, flags); __netpoll_cleanup(&nt->np); spin_lock_irqsave(&target_list_lock, flags); dev_put(nt->np.dev); nt->np.dev = NULL; nt->enabled = false; stopped = true; netconsole_target_put(nt); goto restart; } } netconsole_target_put(nt); } spin_unlock_irqrestore(&target_list_lock, flags); if (stopped) { const char *msg = "had an event"; switch (event) { case NETDEV_UNREGISTER: msg = "unregistered"; break; case NETDEV_RELEASE: msg = "released slaves"; break; case NETDEV_JOIN: msg = "is joining a master device"; break; } pr_info("network logging stopped on interface %s as it %s\n", dev->name, msg); } done: return NOTIFY_DONE; } static struct notifier_block netconsole_netdev_notifier = { .notifier_call = netconsole_netdev_event, }; /** * send_ext_msg_udp - send extended log message to target * @nt: target to send message to * @msg: extended log message to send * @msg_len: length of message * * Transfer extended log @msg to @nt. If @msg is longer than * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with * ncfrag header field added to identify them. */ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, int msg_len) { static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ const char *header, *body; int offset = 0; int header_len, body_len; if (msg_len <= MAX_PRINT_CHUNK) { netpoll_send_udp(&nt->np, msg, msg_len); return; } /* need to insert extra header fields, detect header and body */ header = msg; body = memchr(msg, ';', msg_len); if (WARN_ON_ONCE(!body)) return; header_len = body - header; body_len = msg_len - header_len - 1; body++; /* * Transfer multiple chunks with the following extra header. * "ncfrag=/" */ memcpy(buf, header, header_len); while (offset < body_len) { int this_header = header_len; int this_chunk; this_header += scnprintf(buf + this_header, sizeof(buf) - this_header, ",ncfrag=%d/%d;", offset, body_len); this_chunk = min(body_len - offset, MAX_PRINT_CHUNK - this_header); if (WARN_ON_ONCE(this_chunk <= 0)) return; memcpy(buf + this_header, body + offset, this_chunk); netpoll_send_udp(&nt->np, buf, this_header + this_chunk); offset += this_chunk; } } static void write_ext_msg(struct console *con, const char *msg, unsigned int len) { struct netconsole_target *nt; unsigned long flags; if ((oops_only && !oops_in_progress) || list_empty(&target_list)) return; spin_lock_irqsave(&target_list_lock, flags); list_for_each_entry(nt, &target_list, list) if (nt->extended && nt->enabled && netif_running(nt->np.dev)) send_ext_msg_udp(nt, msg, len); spin_unlock_irqrestore(&target_list_lock, flags); } static void write_msg(struct console *con, const char *msg, unsigned int len) { int frag, left; unsigned long flags; struct netconsole_target *nt; const char *tmp; if (oops_only && !oops_in_progress) return; /* Avoid taking lock and disabling interrupts unnecessarily */ if (list_empty(&target_list)) return; spin_lock_irqsave(&target_list_lock, flags); list_for_each_entry(nt, &target_list, list) { if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) { /* * We nest this inside the for-each-target loop above * so that we're able to get as much logging out to * at least one target if we die inside here, instead * of unnecessarily keeping all targets in lock-step. */ tmp = msg; for (left = len; left;) { frag = min(left, MAX_PRINT_CHUNK); netpoll_send_udp(&nt->np, tmp, frag); tmp += frag; left -= frag; } } } spin_unlock_irqrestore(&target_list_lock, flags); } static struct console netconsole_ext = { .name = "netcon_ext", .flags = CON_EXTENDED, /* starts disabled, registered on first use */ .write = write_ext_msg, }; static struct console netconsole = { .name = "netcon", .flags = CON_ENABLED, .write = write_msg, }; static int __init init_netconsole(void) { int err; struct netconsole_target *nt, *tmp; unsigned long flags; char *target_config; char *input = config; if (strnlen(input, MAX_PARAM_LENGTH)) { while ((target_config = strsep(&input, ";"))) { nt = alloc_param_target(target_config); if (IS_ERR(nt)) { err = PTR_ERR(nt); goto fail; } /* Dump existing printks when we register */ if (nt->extended) netconsole_ext.flags |= CON_PRINTBUFFER | CON_ENABLED; else netconsole.flags |= CON_PRINTBUFFER; spin_lock_irqsave(&target_list_lock, flags); list_add(&nt->list, &target_list); spin_unlock_irqrestore(&target_list_lock, flags); } } err = register_netdevice_notifier(&netconsole_netdev_notifier); if (err) goto fail; err = dynamic_netconsole_init(); if (err) goto undonotifier; if (netconsole_ext.flags & CON_ENABLED) register_console(&netconsole_ext); register_console(&netconsole); pr_info("network logging started\n"); return err; undonotifier: unregister_netdevice_notifier(&netconsole_netdev_notifier); fail: pr_err("cleaning up\n"); /* * Remove all targets and destroy them (only targets created * from the boot/module option exist here). Skipping the list * lock is safe here, and netpoll_cleanup() will sleep. */ list_for_each_entry_safe(nt, tmp, &target_list, list) { list_del(&nt->list); free_param_target(nt); } return err; } static void __exit cleanup_netconsole(void) { struct netconsole_target *nt, *tmp; unregister_console(&netconsole_ext); unregister_console(&netconsole); dynamic_netconsole_exit(); unregister_netdevice_notifier(&netconsole_netdev_notifier); /* * Targets created via configfs pin references on our module * and would first be rmdir(2)'ed from userspace. We reach * here only when they are already destroyed, and only those * created from the boot/module option are left, so remove and * destroy them. Skipping the list lock is safe here, and * netpoll_cleanup() will sleep. */ list_for_each_entry_safe(nt, tmp, &target_list, list) { list_del(&nt->list); free_param_target(nt); } } /* * Use late_initcall to ensure netconsole is * initialized after network device driver if built-in. * * late_initcall() and module_init() are identical if built as module. */ late_initcall(init_netconsole); module_exit(cleanup_netconsole);