1 files changed, 579 insertions, 26 deletions

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 458c4d674a9..69ef1eb03be 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -41,6 +41,8 @@
 #include <linux/moduleparam.h>
 #include <linux/string.h>
 #include <linux/netpoll.h>
+#include <linux/inet.h>
+#include <linux/configfs.h>
 
 MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
 MODULE_DESCRIPTION("Console driver for network interfaces");
@@ -71,20 +73,100 @@ static DEFINE_SPINLOCK(target_list_lock);
 /**
  * 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).
  * @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
+	int			enabled;
 	struct netpoll		np;
 };
 
-/* Allocate new target and setup netpoll for it */
-static struct netconsole_target *alloc_target(char *target_config)
+#ifdef	CONFIG_NETCONSOLE_DYNAMIC
+
+static struct configfs_subsystem netconsole_subsys;
+
+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 */
+	/*
+	 * Allocate and initialize with defaults.
+	 * Note that these targets get their config_item fields zeroed-out.
+	 */
 	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 	if (!nt) {
 		printk(KERN_ERR "netconsole: failed to allocate memory\n");
@@ -106,6 +188,8 @@ static struct netconsole_target *alloc_target(char *target_config)
 	if (err)
 		goto fail;
 
+	nt->enabled = 1;
+
 	return nt;
 
 fail:
@@ -113,13 +197,469 @@ fail:
 	return ERR_PTR(err);
 }
 
-/* Cleanup netpoll for given target and free it */
-static void free_target(struct netconsole_target *nt)
+/* 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/
+ *				|
+ *				<target>/
+ *				|	enabled
+ *				|	dev_name
+ *				|	local_port
+ *				|	remote_port
+ *				|	local_ip
+ *				|	remote_ip
+ *				|	local_mac
+ *				|	remote_mac
+ *				|
+ *				<target>/...
+ */
+
+struct netconsole_target_attr {
+	struct configfs_attribute	attr;
+	ssize_t				(*show)(struct netconsole_target *nt,
+						char *buf);
+	ssize_t				(*store)(struct netconsole_target *nt,
+						 const char *buf,
+						 size_t count);
+};
+
+static struct netconsole_target *to_target(struct config_item *item)
+{
+	return item ?
+		container_of(item, struct netconsole_target, item) :
+		NULL;
+}
+
+/*
+ * Wrapper over simple_strtol (base 10) with sanity and range checking.
+ * We return (signed) long only because we may want to return errors.
+ * Do not use this to convert numbers that are allowed to be negative.
+ */
+static long strtol10_check_range(const char *cp, long min, long max)
+{
+	long ret;
+	char *p = (char *) cp;
+
+	WARN_ON(min < 0);
+	WARN_ON(max < min);
+
+	ret = simple_strtol(p, &p, 10);
+
+	if (*p && (*p != '\n')) {
+		printk(KERN_ERR "netconsole: invalid input\n");
+		return -EINVAL;
+	}
+	if ((ret < min) || (ret > max)) {
+		printk(KERN_ERR "netconsole: input %ld must be between "
+				"%ld and %ld\n", ret, min, max);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+/*
+ * Attribute operations for netconsole_target.
+ */
+
+static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
+}
+
+static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
+}
+
+static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
+}
+
+static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
+}
+
+static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d.%d.%d.%d\n",
+			HIPQUAD(nt->np.local_ip));
+}
+
+static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d.%d.%d.%d\n",
+			HIPQUAD(nt->np.remote_ip));
+}
+
+static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%02x:%02x:%02x:%02x:%02x:%02x\n",
+			nt->np.local_mac[0], nt->np.local_mac[1],
+			nt->np.local_mac[2], nt->np.local_mac[3],
+			nt->np.local_mac[4], nt->np.local_mac[5]);
+}
+
+static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%02x:%02x:%02x:%02x:%02x:%02x\n",
+			nt->np.remote_mac[0], nt->np.remote_mac[1],
+			nt->np.remote_mac[2], nt->np.remote_mac[3],
+			nt->np.remote_mac[4], nt->np.remote_mac[5]);
+}
+
+/*
+ * 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 store_enabled(struct netconsole_target *nt,
+			     const char *buf,
+			     size_t count)
+{
+	int err;
+	long enabled;
+
+	enabled = strtol10_check_range(buf, 0, 1);
+	if (enabled < 0)
+		return enabled;
+
+	if (enabled) {	/* 1 */
+
+		/*
+		 * 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)
+			return err;
+
+		printk(KERN_INFO "netconsole: network logging started\n");
+
+	} else {	/* 0 */
+		netpoll_cleanup(&nt->np);
+	}
+
+	nt->enabled = enabled;
+
+	return strnlen(buf, count);
+}
+
+static ssize_t store_dev_name(struct netconsole_target *nt,
+			      const char *buf,
+			      size_t count)
+{
+	size_t len;
+
+	if (nt->enabled) {
+		printk(KERN_ERR "netconsole: target (%s) is enabled, "
+				"disable to update parameters\n",
+				config_item_name(&nt->item));
+		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';
+
+	return strnlen(buf, count);
+}
+
+static ssize_t store_local_port(struct netconsole_target *nt,
+				const char *buf,
+				size_t count)
+{
+	long local_port;
+#define __U16_MAX	((__u16) ~0U)
+
+	if (nt->enabled) {
+		printk(KERN_ERR "netconsole: target (%s) is enabled, "
+				"disable to update parameters\n",
+				config_item_name(&nt->item));
+		return -EINVAL;
+	}
+
+	local_port = strtol10_check_range(buf, 0, __U16_MAX);
+	if (local_port < 0)
+		return local_port;
+
+	nt->np.local_port = local_port;
+
+	return strnlen(buf, count);
+}
+
+static ssize_t store_remote_port(struct netconsole_target *nt,
+				 const char *buf,
+				 size_t count)
+{
+	long remote_port;
+#define __U16_MAX	((__u16) ~0U)
+
+	if (nt->enabled) {
+		printk(KERN_ERR "netconsole: target (%s) is enabled, "
+				"disable to update parameters\n",
+				config_item_name(&nt->item));
+		return -EINVAL;
+	}
+
+	remote_port = strtol10_check_range(buf, 0, __U16_MAX);
+	if (remote_port < 0)
+		return remote_port;
+
+	nt->np.remote_port = remote_port;
+
+	return strnlen(buf, count);
+}
+
+static ssize_t store_local_ip(struct netconsole_target *nt,
+			      const char *buf,
+			      size_t count)
+{
+	if (nt->enabled) {
+		printk(KERN_ERR "netconsole: target (%s) is enabled, "
+				"disable to update parameters\n",
+				config_item_name(&nt->item));
+		return -EINVAL;
+	}
+
+	nt->np.local_ip = ntohl(in_aton(buf));
+
+	return strnlen(buf, count);
+}
+
+static ssize_t store_remote_ip(struct netconsole_target *nt,
+			       const char *buf,
+			       size_t count)
+{
+	if (nt->enabled) {
+		printk(KERN_ERR "netconsole: target (%s) is enabled, "
+				"disable to update parameters\n",
+				config_item_name(&nt->item));
+		return -EINVAL;
+	}
+
+	nt->np.remote_ip = ntohl(in_aton(buf));
+
+	return strnlen(buf, count);
+}
+
+static ssize_t store_remote_mac(struct netconsole_target *nt,
+				const char *buf,
+				size_t count)
+{
+	u8 remote_mac[ETH_ALEN];
+	char *p = (char *) buf;
+	int i;
+
+	if (nt->enabled) {
+		printk(KERN_ERR "netconsole: target (%s) is enabled, "
+				"disable to update parameters\n",
+				config_item_name(&nt->item));
+		return -EINVAL;
+	}
+
+	for (i = 0; i < ETH_ALEN - 1; i++) {
+		remote_mac[i] = simple_strtoul(p, &p, 16);
+		if (*p != ':')
+			goto invalid;
+		p++;
+	}
+	remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
+	if (*p && (*p != '\n'))
+		goto invalid;
+
+	memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
+
+	return strnlen(buf, count);
+
+invalid:
+	printk(KERN_ERR "netconsole: invalid input\n");
+	return -EINVAL;
+}
+
+/*
+ * Attribute definitions for netconsole_target.
+ */
+
+#define NETCONSOLE_TARGET_ATTR_RO(_name)				\
+static struct netconsole_target_attr netconsole_target_##_name =	\
+	__CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
+
+#define NETCONSOLE_TARGET_ATTR_RW(_name)				\
+static struct netconsole_target_attr netconsole_target_##_name =	\
+	__CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
+
+NETCONSOLE_TARGET_ATTR_RW(enabled);
+NETCONSOLE_TARGET_ATTR_RW(dev_name);
+NETCONSOLE_TARGET_ATTR_RW(local_port);
+NETCONSOLE_TARGET_ATTR_RW(remote_port);
+NETCONSOLE_TARGET_ATTR_RW(local_ip);
+NETCONSOLE_TARGET_ATTR_RW(remote_ip);
+NETCONSOLE_TARGET_ATTR_RO(local_mac);
+NETCONSOLE_TARGET_ATTR_RW(remote_mac);
+
+static struct configfs_attribute *netconsole_target_attrs[] = {
+	&netconsole_target_enabled.attr,
+	&netconsole_target_dev_name.attr,
+	&netconsole_target_local_port.attr,
+	&netconsole_target_remote_port.attr,
+	&netconsole_target_local_ip.attr,
+	&netconsole_target_remote_ip.attr,
+	&netconsole_target_local_mac.attr,
+	&netconsole_target_remote_mac.attr,
+	NULL,
+};
+
+/*
+ * Item operations and type for netconsole_target.
+ */
+
+static void netconsole_target_release(struct config_item *item)
+{
+	kfree(to_target(item));
+}
+
+static ssize_t netconsole_target_attr_show(struct config_item *item,
+					   struct configfs_attribute *attr,
+					   char *buf)
+{
+	ssize_t ret = -EINVAL;
+	struct netconsole_target *nt = to_target(item);
+	struct netconsole_target_attr *na =
+		container_of(attr, struct netconsole_target_attr, attr);
+
+	if (na->show)
+		ret = na->show(nt, buf);
+
+	return ret;
+}
+
+static ssize_t netconsole_target_attr_store(struct config_item *item,
+					    struct configfs_attribute *attr,
+					    const char *buf,
+					    size_t count)
+{
+	ssize_t ret = -EINVAL;
+	struct netconsole_target *nt = to_target(item);
+	struct netconsole_target_attr *na =
+		container_of(attr, struct netconsole_target_attr, attr);
+
+	if (na->store)
+		ret = na->store(nt, buf, count);
+
+	return ret;
+}
+
+static struct configfs_item_operations netconsole_target_item_ops = {
+	.release		= netconsole_target_release,
+	.show_attribute		= netconsole_target_attr_show,
+	.store_attribute	= netconsole_target_attr_store,
+};
+
+static 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 == 0).
+	 */
+	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
+	if (!nt) {
+		printk(KERN_ERR "netconsole: failed to allocate memory\n");
+		return NULL;
+	}
+
+	nt->np.name = "netconsole";
+	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
+	nt->np.local_port = 6665;
+	nt->np.remote_port = 6666;
+	memset(nt->np.remote_mac, 0xff, ETH_ALEN);
+
+	/* 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 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,
@@ -134,6 +674,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
 
 	spin_lock_irqsave(&target_list_lock, flags);
 	list_for_each_entry(nt, &target_list, list) {
+		netconsole_target_get(nt);
 		if (nt->np.dev == dev) {
 			switch (event) {
 			case NETDEV_CHANGEADDR:
@@ -145,6 +686,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
 				break;
 			}
 		}
+		netconsole_target_put(nt);
 	}
 	spin_unlock_irqrestore(&target_list_lock, flags);
 
@@ -169,7 +711,8 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
 
 	spin_lock_irqsave(&target_list_lock, flags);
 	list_for_each_entry(nt, &target_list, list) {
-		if (netif_running(nt->np.dev)) {
+		netconsole_target_get(nt);
+		if (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
@@ -184,6 +727,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
 				left -= frag;
 			}
 		}
+		netconsole_target_put(nt);
 	}
 	spin_unlock_irqrestore(&target_list_lock, flags);
 }
@@ -196,48 +740,52 @@ static struct console netconsole = {
 
 static int __init init_netconsole(void)
 {
-	int err = 0;
+	int err;
 	struct netconsole_target *nt, *tmp;
 	unsigned long flags;
 	char *target_config;
 	char *input = config;
 
-	if (!strnlen(input, MAX_PARAM_LENGTH)) {
-		printk(KERN_INFO "netconsole: not configured, aborting\n");
-		goto out;
-	}
-
-	while ((target_config = strsep(&input, ";"))) {
-		nt = alloc_target(target_config);
-		if (IS_ERR(nt)) {
-			err = PTR_ERR(nt);
-			goto fail;
+	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;
+			}
+			spin_lock_irqsave(&target_list_lock, flags);
+			list_add(&nt->list, &target_list);
+			spin_unlock_irqrestore(&target_list_lock, flags);
 		}
-		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;
+
 	register_console(&netconsole);
 	printk(KERN_INFO "netconsole: network logging started\n");
 
-out:
 	return err;
 
+undonotifier:
+	unregister_netdevice_notifier(&netconsole_netdev_notifier);
+
 fail:
 	printk(KERN_ERR "netconsole: cleaning up\n");
 
 	/*
-	 * Remove all targets and destroy them. Skipping the list
+	 * 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_target(nt);
+		free_param_target(nt);
 	}
 
 	return err;
@@ -248,15 +796,20 @@ static void __exit cleanup_netconsole(void)
 	struct netconsole_target *nt, *tmp;
 
 	unregister_console(&netconsole);
+	dynamic_netconsole_exit();
 	unregister_netdevice_notifier(&netconsole_netdev_notifier);
 
 	/*
-	 * Remove all targets and destroy them. Skipping the list
-	 * lock is safe here, and netpoll_cleanup() will sleep.
+	 * 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_target(nt);
+		free_param_target(nt);
 	}
 }