// 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 #include #include MODULE_AUTHOR("Matt Mackall "); MODULE_DESCRIPTION("Console driver for network interfaces"); MODULE_LICENSE("GPL"); #define MAX_PARAM_LENGTH 256 #define MAX_USERDATA_ENTRY_LENGTH 256 #define MAX_USERDATA_VALUE_LENGTH 200 /* The number 3 comes from userdata entry format characters (' ', '=', '\n') */ #define MAX_USERDATA_NAME_LENGTH (MAX_USERDATA_ENTRY_LENGTH - \ MAX_USERDATA_VALUE_LENGTH - 3) #define MAX_USERDATA_ITEMS 16 #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; module_param(oops_only, bool, 0600); MODULE_PARM_DESC(oops_only, "Only log oops messages"); #define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline" #ifndef MODULE static int __init option_setup(char *opt) { strscpy(config, opt, MAX_PARAM_LENGTH); return 1; } __setup("netconsole=", option_setup); #endif /* MODULE */ /* Linked list of all configured targets */ static LIST_HEAD(target_list); /* target_cleanup_list is used to track targets that need to be cleaned outside * of target_list_lock. It should be cleaned in the same function it is * populated. */ static LIST_HEAD(target_cleanup_list); /* This needs to be a spinlock because write_msg() cannot sleep */ static DEFINE_SPINLOCK(target_list_lock); /* This needs to be a mutex because netpoll_cleanup might sleep */ static DEFINE_MUTEX(target_cleanup_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. * @group: Links us into the configfs subsystem hierarchy. * @userdata_group: Links to the userdata configfs hierarchy * @userdata_complete: Cached, formatted string of append * @userdata_length: String length of userdata_complete * @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. * @release: Denotes whether kernel release version should be prepended * to the message. Depends on extended console. * @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_group group; struct config_group userdata_group; char userdata_complete[MAX_USERDATA_ENTRY_LENGTH * MAX_USERDATA_ITEMS]; size_t userdata_length; #endif bool enabled; bool extended; bool release; 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->group.cg_item)) config_group_get(&nt->group); } static void netconsole_target_put(struct netconsole_target *nt) { if (config_item_name(&nt->group.cg_item)) config_group_put(&nt->group); } #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) { } static void populate_configfs_item(struct netconsole_target *nt, int cmdline_count) { } #endif /* CONFIG_NETCONSOLE_DYNAMIC */ /* Allocate and initialize with defaults. * Note that these targets get their config_item fields zeroed-out. */ static struct netconsole_target *alloc_and_init(void) { struct netconsole_target *nt; nt = kzalloc(sizeof(*nt), GFP_KERNEL); if (!nt) return nt; if (IS_ENABLED(CONFIG_NETCONSOLE_EXTENDED_LOG)) nt->extended = true; if (IS_ENABLED(CONFIG_NETCONSOLE_PREPEND_RELEASE)) nt->release = true; nt->np.name = "netconsole"; strscpy(nt->np.dev_name, "eth0", IFNAMSIZ); nt->np.local_port = 6665; nt->np.remote_port = 6666; eth_broadcast_addr(nt->np.remote_mac); return nt; } /* Clean up every target in the cleanup_list and move the clean targets back to * the main target_list. */ static void netconsole_process_cleanups_core(void) { struct netconsole_target *nt, *tmp; unsigned long flags; /* The cleanup needs RTNL locked */ ASSERT_RTNL(); mutex_lock(&target_cleanup_list_lock); list_for_each_entry_safe(nt, tmp, &target_cleanup_list, list) { /* all entries in the cleanup_list needs to be disabled */ WARN_ON_ONCE(nt->enabled); do_netpoll_cleanup(&nt->np); /* moved the cleaned target to target_list. Need to hold both * locks */ spin_lock_irqsave(&target_list_lock, flags); list_move(&nt->list, &target_list); spin_unlock_irqrestore(&target_list_lock, flags); } WARN_ON_ONCE(!list_empty(&target_cleanup_list)); mutex_unlock(&target_cleanup_list_lock); } #ifdef CONFIG_NETCONSOLE_DYNAMIC /* * Our subsystem hierarchy is: * * /sys/kernel/config/netconsole/ * | * / * | enabled * | release * | dev_name * | local_port * | remote_port * | local_ip * | remote_ip * | local_mac * | remote_mac * | userdata/ * | / * | value * | ... * | * /... */ static struct netconsole_target *to_target(struct config_item *item) { struct config_group *cfg_group; cfg_group = to_config_group(item); if (!cfg_group) return NULL; return container_of(to_config_group(item), struct netconsole_target, group); } /* Do the list cleanup with the rtnl lock hold. rtnl lock is necessary because * netdev might be cleaned-up by calling __netpoll_cleanup(), */ static void netconsole_process_cleanups(void) { /* rtnl lock is called here, because it has precedence over * target_cleanup_list_lock mutex and target_cleanup_list */ rtnl_lock(); netconsole_process_cleanups_core(); rtnl_unlock(); } /* Get rid of possible trailing newline, returning the new length */ static void trim_newline(char *s, size_t maxlen) { size_t len; len = strnlen(s, maxlen); if (s[len - 1] == '\n') s[len - 1] = '\0'; } /* * Attribute operations for netconsole_target. */ static ssize_t enabled_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%d\n", to_target(item)->enabled); } static ssize_t extended_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%d\n", to_target(item)->extended); } static ssize_t release_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%d\n", to_target(item)->release); } static ssize_t dev_name_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%s\n", to_target(item)->np.dev_name); } static ssize_t local_port_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%d\n", to_target(item)->np.local_port); } static ssize_t remote_port_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%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 sysfs_emit(buf, "%pI6c\n", &nt->np.local_ip.in6); else return sysfs_emit(buf, "%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 sysfs_emit(buf, "%pI6c\n", &nt->np.remote_ip.in6); else return sysfs_emit(buf, "%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 sysfs_emit(buf, "%pM\n", dev ? dev->dev_addr : bcast); } static ssize_t remote_mac_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%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; bool enabled; ssize_t ret; mutex_lock(&dynamic_netconsole_mutex); ret = kstrtobool(buf, &enabled); if (ret) goto out_unlock; ret = -EINVAL; if (enabled == nt->enabled) { pr_info("network logging has already %s\n", nt->enabled ? "started" : "stopped"); goto out_unlock; } if (enabled) { /* true */ if (nt->release && !nt->extended) { pr_err("Not enabling netconsole. Release feature requires extended log message"); goto out_unlock; } if (nt->extended && !console_is_registered(&netconsole_ext)) 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); ret = netpoll_setup(&nt->np); if (ret) goto out_unlock; nt->enabled = true; 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 */ mutex_lock(&target_cleanup_list_lock); spin_lock_irqsave(&target_list_lock, flags); nt->enabled = false; /* Remove the target from the list, while holding * target_list_lock */ list_move(&nt->list, &target_cleanup_list); spin_unlock_irqrestore(&target_list_lock, flags); mutex_unlock(&target_cleanup_list_lock); } ret = strnlen(buf, count); /* Deferred cleanup */ netconsole_process_cleanups(); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } static ssize_t release_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); bool release; ssize_t ret; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_item)); ret = -EINVAL; goto out_unlock; } ret = kstrtobool(buf, &release); if (ret) goto out_unlock; nt->release = release; ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } static ssize_t extended_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); bool extended; ssize_t ret; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_item)); ret = -EINVAL; goto out_unlock; } ret = kstrtobool(buf, &extended); if (ret) goto out_unlock; nt->extended = extended; ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } static ssize_t dev_name_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->group.cg_item)); mutex_unlock(&dynamic_netconsole_mutex); return -EINVAL; } strscpy(nt->np.dev_name, buf, IFNAMSIZ); trim_newline(nt->np.dev_name, IFNAMSIZ); 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); ssize_t ret = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_item)); goto out_unlock; } ret = kstrtou16(buf, 10, &nt->np.local_port); if (ret < 0) goto out_unlock; ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } static ssize_t remote_port_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); ssize_t ret = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_item)); goto out_unlock; } ret = kstrtou16(buf, 10, &nt->np.remote_port); if (ret < 0) goto out_unlock; ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } static ssize_t local_ip_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); ssize_t ret = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_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; } ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } static ssize_t remote_ip_store(struct config_item *item, const char *buf, size_t count) { struct netconsole_target *nt = to_target(item); ssize_t ret = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_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; } ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } 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]; ssize_t ret = -EINVAL; mutex_lock(&dynamic_netconsole_mutex); if (nt->enabled) { pr_err("target (%s) is enabled, disable to update parameters\n", config_item_name(&nt->group.cg_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); ret = strnlen(buf, count); out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } struct userdatum { struct config_item item; char value[MAX_USERDATA_VALUE_LENGTH]; }; static struct userdatum *to_userdatum(struct config_item *item) { return container_of(item, struct userdatum, item); } struct userdata { struct config_group group; }; static struct userdata *to_userdata(struct config_item *item) { return container_of(to_config_group(item), struct userdata, group); } static struct netconsole_target *userdata_to_target(struct userdata *ud) { struct config_group *netconsole_group; netconsole_group = to_config_group(ud->group.cg_item.ci_parent); return to_target(&netconsole_group->cg_item); } static ssize_t userdatum_value_show(struct config_item *item, char *buf) { return sysfs_emit(buf, "%s\n", &(to_userdatum(item)->value[0])); } static void update_userdata(struct netconsole_target *nt) { int complete_idx = 0, child_count = 0; struct list_head *entry; /* Clear the current string in case the last userdatum was deleted */ nt->userdata_length = 0; nt->userdata_complete[0] = 0; list_for_each(entry, &nt->userdata_group.cg_children) { struct userdatum *udm_item; struct config_item *item; if (child_count >= MAX_USERDATA_ITEMS) break; child_count++; item = container_of(entry, struct config_item, ci_entry); udm_item = to_userdatum(item); /* Skip userdata with no value set */ if (strnlen(udm_item->value, MAX_USERDATA_VALUE_LENGTH) == 0) continue; /* This doesn't overflow userdata_complete since it will write * one entry length (1/MAX_USERDATA_ITEMS long), entry count is * checked to not exceed MAX items with child_count above */ complete_idx += scnprintf(&nt->userdata_complete[complete_idx], MAX_USERDATA_ENTRY_LENGTH, " %s=%s\n", item->ci_name, udm_item->value); } nt->userdata_length = strnlen(nt->userdata_complete, sizeof(nt->userdata_complete)); } static ssize_t userdatum_value_store(struct config_item *item, const char *buf, size_t count) { struct userdatum *udm = to_userdatum(item); struct netconsole_target *nt; struct userdata *ud; ssize_t ret; if (count > MAX_USERDATA_VALUE_LENGTH) return -EMSGSIZE; mutex_lock(&dynamic_netconsole_mutex); ret = strscpy(udm->value, buf, sizeof(udm->value)); if (ret < 0) goto out_unlock; trim_newline(udm->value, sizeof(udm->value)); ud = to_userdata(item->ci_parent); nt = userdata_to_target(ud); update_userdata(nt); ret = count; out_unlock: mutex_unlock(&dynamic_netconsole_mutex); return ret; } CONFIGFS_ATTR(userdatum_, value); static struct configfs_attribute *userdatum_attrs[] = { &userdatum_attr_value, NULL, }; static void userdatum_release(struct config_item *item) { kfree(to_userdatum(item)); } static struct configfs_item_operations userdatum_ops = { .release = userdatum_release, }; static const struct config_item_type userdatum_type = { .ct_item_ops = &userdatum_ops, .ct_attrs = userdatum_attrs, .ct_owner = THIS_MODULE, }; static struct config_item *userdatum_make_item(struct config_group *group, const char *name) { struct netconsole_target *nt; struct userdatum *udm; struct userdata *ud; size_t child_count; if (strlen(name) > MAX_USERDATA_NAME_LENGTH) return ERR_PTR(-ENAMETOOLONG); ud = to_userdata(&group->cg_item); nt = userdata_to_target(ud); child_count = list_count_nodes(&nt->userdata_group.cg_children); if (child_count >= MAX_USERDATA_ITEMS) return ERR_PTR(-ENOSPC); udm = kzalloc(sizeof(*udm), GFP_KERNEL); if (!udm) return ERR_PTR(-ENOMEM); config_item_init_type_name(&udm->item, name, &userdatum_type); return &udm->item; } static void userdatum_drop(struct config_group *group, struct config_item *item) { struct netconsole_target *nt; struct userdata *ud; ud = to_userdata(&group->cg_item); nt = userdata_to_target(ud); mutex_lock(&dynamic_netconsole_mutex); update_userdata(nt); config_item_put(item); mutex_unlock(&dynamic_netconsole_mutex); } static struct configfs_attribute *userdata_attrs[] = { NULL, }; static struct configfs_group_operations userdata_ops = { .make_item = userdatum_make_item, .drop_item = userdatum_drop, }; static const struct config_item_type userdata_type = { .ct_item_ops = &userdatum_ops, .ct_group_ops = &userdata_ops, .ct_attrs = userdata_attrs, .ct_owner = THIS_MODULE, }; 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); CONFIGFS_ATTR(, release); static struct configfs_attribute *netconsole_target_attrs[] = { &attr_enabled, &attr_extended, &attr_release, &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, }; static void init_target_config_group(struct netconsole_target *nt, const char *name) { config_group_init_type_name(&nt->group, name, &netconsole_target_type); config_group_init_type_name(&nt->userdata_group, "userdata", &userdata_type); configfs_add_default_group(&nt->userdata_group, &nt->group); } static struct netconsole_target *find_cmdline_target(const char *name) { struct netconsole_target *nt, *ret = NULL; unsigned long flags; spin_lock_irqsave(&target_list_lock, flags); list_for_each_entry(nt, &target_list, list) { if (!strcmp(nt->group.cg_item.ci_name, name)) { ret = nt; break; } } spin_unlock_irqrestore(&target_list_lock, flags); return ret; } /* * Group operations and type for netconsole_subsys. */ static struct config_group *make_netconsole_target(struct config_group *group, const char *name) { struct netconsole_target *nt; unsigned long flags; /* Checking if a target by this name was created at boot time. If so, * attach a configfs entry to that target. This enables dynamic * control. */ if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX, strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) { nt = find_cmdline_target(name); if (nt) { init_target_config_group(nt, name); return &nt->group; } } nt = alloc_and_init(); if (!nt) return ERR_PTR(-ENOMEM); /* Initialize the config_group member */ init_target_config_group(nt, name); /* 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->group; } 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->group.cg_item); } static struct configfs_group_operations netconsole_subsys_group_ops = { .make_group = 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, }, }, }; static void populate_configfs_item(struct netconsole_target *nt, int cmdline_count) { char target_name[16]; snprintf(target_name, sizeof(target_name), "%s%d", NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count); init_target_config_group(nt, target_name); } #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, *tmp; 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; mutex_lock(&target_cleanup_list_lock); spin_lock_irqsave(&target_list_lock, flags); list_for_each_entry_safe(nt, tmp, &target_list, list) { netconsole_target_get(nt); if (nt->np.dev == dev) { switch (event) { case NETDEV_CHANGENAME: strscpy(nt->np.dev_name, dev->name, IFNAMSIZ); break; case NETDEV_RELEASE: case NETDEV_JOIN: case NETDEV_UNREGISTER: nt->enabled = false; list_move(&nt->list, &target_cleanup_list); stopped = true; } } netconsole_target_put(nt); } spin_unlock_irqrestore(&target_list_lock, flags); mutex_unlock(&target_cleanup_list_lock); 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); } /* Process target_cleanup_list entries. By the end, target_cleanup_list * should be empty */ netconsole_process_cleanups_core(); done: return NOTIFY_DONE; } static struct notifier_block netconsole_netdev_notifier = { .notifier_call = netconsole_netdev_event, }; static void send_msg_no_fragmentation(struct netconsole_target *nt, const char *msg, int msg_len, int release_len) { static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ const char *userdata = NULL; const char *release; #ifdef CONFIG_NETCONSOLE_DYNAMIC userdata = nt->userdata_complete; #endif if (release_len) { release = init_utsname()->release; scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg); msg_len += release_len; } else { memcpy(buf, msg, msg_len); } if (userdata) msg_len += scnprintf(&buf[msg_len], MAX_PRINT_CHUNK - msg_len, "%s", userdata); netpoll_send_udp(&nt->np, buf, msg_len); } static void append_release(char *buf) { const char *release; release = init_utsname()->release; scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); } static void send_fragmented_body(struct netconsole_target *nt, char *buf, const char *msgbody, int header_len, int msgbody_len) { const char *userdata = NULL; int body_len, offset = 0; int userdata_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC userdata = nt->userdata_complete; userdata_len = nt->userdata_length; #endif /* body_len represents the number of bytes that will be sent. This is * bigger than MAX_PRINT_CHUNK, thus, it will be split in multiple * packets */ body_len = msgbody_len + userdata_len; /* In each iteration of the while loop below, we send a packet * containing the header and a portion of the body. The body is * composed of two parts: msgbody and userdata. We keep track of how * many bytes have been sent so far using the offset variable, which * ranges from 0 to the total length of the body. */ while (offset < body_len) { int this_header = header_len; bool msgbody_written = false; int this_offset = 0; int this_chunk = 0; this_header += scnprintf(buf + this_header, MAX_PRINT_CHUNK - this_header, ",ncfrag=%d/%d;", offset, body_len); /* Not all msgbody data has been written yet */ if (offset < msgbody_len) { this_chunk = min(msgbody_len - offset, MAX_PRINT_CHUNK - this_header); if (WARN_ON_ONCE(this_chunk <= 0)) return; memcpy(buf + this_header, msgbody + offset, this_chunk); this_offset += this_chunk; } /* msgbody was finally written, either in the previous * messages and/or in the current buf. Time to write * the userdata. */ msgbody_written |= offset + this_offset >= msgbody_len; /* Msg body is fully written and there is pending userdata to * write, append userdata in this chunk */ if (msgbody_written && offset + this_offset < body_len) { /* Track how much user data was already sent. First * time here, sent_userdata is zero */ int sent_userdata = (offset + this_offset) - msgbody_len; /* offset of bytes used in current buf */ int preceding_bytes = this_chunk + this_header; if (WARN_ON_ONCE(sent_userdata < 0)) return; this_chunk = min(userdata_len - sent_userdata, MAX_PRINT_CHUNK - preceding_bytes); if (WARN_ON_ONCE(this_chunk < 0)) /* this_chunk could be zero if all the previous * message used all the buffer. This is not a * problem, userdata will be sent in the next * iteration */ return; memcpy(buf + this_header + this_offset, userdata + sent_userdata, this_chunk); this_offset += this_chunk; } netpoll_send_udp(&nt->np, buf, this_header + this_offset); offset += this_offset; } } static void send_msg_fragmented(struct netconsole_target *nt, const char *msg, int msg_len, int release_len) { static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ int header_len, msgbody_len; const char *msgbody; /* need to insert extra header fields, detect header and msgbody */ msgbody = memchr(msg, ';', msg_len); if (WARN_ON_ONCE(!msgbody)) return; header_len = msgbody - msg; msgbody_len = msg_len - header_len - 1; msgbody++; /* * Transfer multiple chunks with the following extra header. * "ncfrag=/" */ if (release_len) append_release(buf); /* Copy the header into the buffer */ memcpy(buf + release_len, msg, header_len); header_len += release_len; /* for now on, the header will be persisted, and the msgbody * will be replaced */ send_fragmented_body(nt, buf, msgbody, header_len, msgbody_len); } /** * 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) { int userdata_len = 0; int release_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC userdata_len = nt->userdata_length; #endif if (nt->release) release_len = strlen(init_utsname()->release) + 1; if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) return send_msg_no_fragmentation(nt, msg, msg_len, release_len); return send_msg_fragmented(nt, msg, msg_len, release_len); } 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); } /* Allocate new target (from boot/module param) and setup netpoll for it */ static struct netconsole_target *alloc_param_target(char *target_config, int cmdline_count) { struct netconsole_target *nt; int err; nt = alloc_and_init(); if (!nt) { err = -ENOMEM; goto fail; } if (*target_config == '+') { nt->extended = true; target_config++; } if (*target_config == 'r') { if (!nt->extended) { pr_err("Netconsole configuration error. Release feature requires extended log message"); err = -EINVAL; goto fail; } nt->release = 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) { pr_err("Not enabling netconsole for %s%d. Netpoll setup failed\n", NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count); if (!IS_ENABLED(CONFIG_NETCONSOLE_DYNAMIC)) /* only fail if dynamic reconfiguration is set, * otherwise, keep the target in the list, but disabled. */ goto fail; } else { nt->enabled = true; } populate_configfs_item(nt, cmdline_count); 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); } static struct console netconsole_ext = { .name = "netcon_ext", .flags = CON_ENABLED | CON_EXTENDED, .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 int count = 0; bool extended = false; 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, count); if (IS_ERR(nt)) { if (IS_ENABLED(CONFIG_NETCONSOLE_DYNAMIC)) continue; err = PTR_ERR(nt); goto fail; } /* Dump existing printks when we register */ if (nt->extended) { extended = true; netconsole_ext.flags |= CON_PRINTBUFFER; } 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); count++; } } err = register_netdevice_notifier(&netconsole_netdev_notifier); if (err) goto fail; err = dynamic_netconsole_init(); if (err) goto undonotifier; if (extended) 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; if (console_is_registered(&netconsole_ext)) 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);