add wireless measurement probe infrastructure, developed at Fraunhofer FOKUS

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@15050 3c298f89-4303-0410-b956-a3cf2f4a3e73

4 files changed, 1068 insertions, 0 deletions

diff --git a/package/wprobe/src/kernel/Makefile b/package/wprobe/src/kernel/Makefile
new file mode 100644
index 0000000000..2a9875311e
--- /dev/null
+++ b/package/wprobe/src/kernel/Makefile
@@ -0,0 +1,5 @@
+EXTRA_CFLAGS += -I.
+
+obj-m := wprobe.o wprobe-dummy.o
+
+wprobe-objs := wprobe-core.o
diff --git a/package/wprobe/src/kernel/linux/wprobe.h b/package/wprobe/src/kernel/linux/wprobe.h
new file mode 100644
index 0000000000..f145195cd4
--- /dev/null
+++ b/package/wprobe/src/kernel/linux/wprobe.h
@@ -0,0 +1,298 @@
+/*
+ * wprobe.h: API for the wireless probe interface
+ * Copyright (C) 2008-2009 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __WPROBE_H
+#define __WPROBE_H
+
+#ifdef __KERNEL__
+#include <linux/types.h>
+#include <linux/if_ether.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <net/genetlink.h>
+#endif
+
+/** 
+ * enum wprobe_attr: netlink attribute list
+ *
+ * @WPROBE_ATTR_UNSPEC: unused
+ *
+ * @WPROBE_ATTR_INTERFACE: interface name to process query on (NLA_STRING)
+ * @WPROBE_ATTR_MAC: mac address (used for wireless links) (NLA_STRING)
+ * @WPROBE_ATTR_FLAGS: interface/link/attribute flags (see enum wprobe_flags) (NLA_U32)
+ * @WPROBE_ATTR_DURATION: sampling duration (in milliseconds) (NLA_MSECS)
+ *
+ * @WPROBE_ATTR_ID: attribute id (NLA_U32)
+ * @WPROBE_ATTR_NAME: attribute name (NLA_STRING)
+ * @WPROBE_ATTR_TYPE: attribute type (NLA_U8)
+ * @WPROBE_ATTR_SCALE: attribute scale factor (NLA_U32)
+ *
+ * attribute values:
+ *
+ * @WPROBE_VAL_STRING: string value (NLA_STRING)
+ * @WPROBE_VAL_S8: signed 8-bit integer (NLA_U8)
+ * @WPROBE_VAL_S16: signed 16-bit integer (NLA_U16)
+ * @WPROBE_VAL_S32: signed 32-bit integer (NLA_U32)
+ * @WPROBE_VAL_S64: signed 64-bit integer (NLA_U64)
+ * @WPROBE_VAL_U8: unsigned 8-bit integer (NLA_U8)
+ * @WPROBE_VAL_U16: unsigned 16-bit integer (NLA_U16)
+ * @WPROBE_VAL_U32: unsigned 32-bit integer (NLA_U32)
+ * @WPROBE_VAL_U64: unsigned 64-bit integer (NLA_U64)
+ *
+ * statistics:
+ * @WPROBE_VAL_SUM: sum of all samples
+ * @WPROBE_VAL_SUM_SQ: sum of all samples^2
+ * @WPROBE_VAL_SAMPLES: number of samples
+ *
+ * @WPROBE_ATTR_LAST: unused
+ */
+enum wprobe_attr {
+	WPROBE_ATTR_UNSPEC,
+	WPROBE_ATTR_INTERFACE,
+	WPROBE_ATTR_MAC,
+	WPROBE_ATTR_FLAGS,
+	WPROBE_ATTR_DURATION,
+	WPROBE_ATTR_SCALE,
+	/* end of query attributes */
+
+	/* response data */
+	WPROBE_ATTR_ID,
+	WPROBE_ATTR_NAME,
+	WPROBE_ATTR_TYPE,
+
+	/* value type attributes */
+	WPROBE_VAL_STRING,
+	WPROBE_VAL_S8,
+	WPROBE_VAL_S16,
+	WPROBE_VAL_S32,
+	WPROBE_VAL_S64,
+	WPROBE_VAL_U8,
+	WPROBE_VAL_U16,
+	WPROBE_VAL_U32,
+	WPROBE_VAL_U64,
+
+	/* aggregates for statistics */
+	WPROBE_VAL_SUM,
+	WPROBE_VAL_SUM_SQ,
+	WPROBE_VAL_SAMPLES,
+
+	WPROBE_ATTR_LAST
+};
+
+
+/**
+ * enum wprobe_cmd: netlink commands for interacting with wprobe
+ *
+ * @WPROBE_CMD_UNSPEC: unused
+ *
+ * @WPROBE_CMD_GET_LIST: get global/link property list
+ * @WPROBE_CMD_GET_INFO: get global/link properties
+ * @WPROBE_CMD_SET_FLAGS: set global/link flags
+ * @WPROBE_CMD_MEASURE: take a snapshot of the current data
+ * @WPROBE_CMD_GET_LINKS: get a list of links
+ *
+ * @WPROBE_CMD_LAST: unused
+ * 
+ * options for GET_INFO and SET_FLAGS:
+ *   - mac address set: per-link
+ *   - mac address unset: globalsa
+ */
+enum wprobe_cmd {
+	WPROBE_CMD_UNSPEC,
+	WPROBE_CMD_GET_LIST,
+	WPROBE_CMD_GET_INFO,
+	WPROBE_CMD_SET_FLAGS,
+	WPROBE_CMD_MEASURE,
+	WPROBE_CMD_GET_LINKS,
+	WPROBE_CMD_LAST
+};
+
+/**
+ * enum wprobe_flags: flags for wprobe links and items
+ * @WPROBE_F_KEEPSTAT: keep statistics for this link/device
+ * @WPROBE_F_RESET: reset statistics now (used only in WPROBE_CMD_SET_LINK)
+ * @WPROBE_F_NEWDATA: used to indicate that a value has been updated
+ */
+enum wprobe_flags {
+	WPROBE_F_KEEPSTAT = (1 << 0),
+	WPROBE_F_RESET = (1 << 1),
+	WPROBE_F_NEWDATA = (1 << 2),
+};
+
+#ifdef __KERNEL__
+
+struct wprobe_link;
+struct wprobe_item;
+struct wprobe_source;
+
+/**
+ * struct wprobe_link - data structure describing a wireless link
+ * @iface: pointer to the wprobe_iface that this link belongs to
+ * @addr: BSSID of the remote link partner
+ * @flags: link flags (see wprobe_flags)
+ * @priv: user pointer
+ *
+ * @list: for internal use
+ * @val: for internal use
+ */
+struct wprobe_link {
+	struct list_head list;
+	struct wprobe_iface *iface;
+	char addr[ETH_ALEN];
+	u32 flags;
+	void *priv;
+	void *val;
+};
+
+/** 
+ * struct wprobe_item - data structure describing the format of wprobe_link::data or wprobe_iface::data
+ * @name: name of the field
+ * @type: data type of this field
+ * @flags: measurement item flags (see wprobe_flags)
+ */
+struct wprobe_item {
+	const char *name;
+	enum wprobe_attr type;
+	u32 flags;
+};
+
+struct wprobe_value {
+	bool pending;
+	union {
+		/*
+		 * the following are kept uppercase to allow
+		 * for automated checking against WPROBE_VAL_*
+		 * via BUG_ON()
+		 */
+		const char *STRING;
+		u8 U8;
+		u16 U16;
+		u32 U32;
+		u64 U64;
+		s8 S8;
+		s16 S16;
+		s32 S32;
+		s64 S64;
+	};
+	s64 s, ss;
+	unsigned int n;
+
+	/* timestamps */
+	u64 first, last;
+};
+
+/**
+ * struct wprobe_source - data structure describing a wireless interface
+ *
+ * @name: name of the interface
+ * @addr: local mac address of the interface
+ * @links: list of wireless links to poll
+ * @link_items: description of the per-link data structure
+ * @n_link_items: number of link description items
+ * @global_items: description of the per-interface data structure
+ * @n_global_items: number of per-interface description items
+ * @sync_data: callback allowing the driver to prepare data for the wprobe poll
+ *
+ * @list: head for the list of interfaces
+ * @priv: user pointer
+ * @lock: spinlock protecting value data access
+ * @val: internal use
+ * @query_val: internal use
+ *
+ * if sync_data is NULL, wprobe assumes that it can access the data structure
+ * at any time (in atomic context). if sync_data returns a negative error code,
+ * the poll request will not be handled for the given link
+ */
+struct wprobe_iface {
+	/* to be filled in by wprobe source drivers */
+	const char *name;
+	const char *addr;
+	const struct wprobe_item *link_items;
+	int n_link_items;
+	const struct wprobe_item *global_items;
+	int n_global_items;
+
+	int (*sync_data)(struct wprobe_iface *dev, struct wprobe_link *l, struct wprobe_value *val, bool measure);
+	void *priv;
+
+	/* handled by the wprobe core */
+	struct list_head list;
+	struct list_head links;
+	spinlock_t lock;
+	void *val;
+	void *query_val;
+};
+
+#define WPROBE_FILL_BEGIN(_ptr, _list) do {			\
+	struct wprobe_value *__val = (_ptr);			\
+	const struct wprobe_item *__item = _list;		\
+	u64 __msecs = jiffies_to_msecs(jiffies)
+
+#define WPROBE_SET(_idx, _type, _value)				\
+	if (__item[_idx].type != WPROBE_VAL_##_type) {		\
+		printk("ERROR: invalid data type at %s:%d\n", __FILE__, __LINE__); \
+		break;						\
+	}							\
+	__val[_idx].pending = true;				\
+	__val[_idx]._type = _value;				\
+	if (!__val[_idx].first)					\
+		__val[_idx].first = __msecs;			\
+	__val[_idx].first = __msecs
+
+#define WPROBE_FILL_END()					\
+} while(0)
+
+/**
+ * wprobe_add_iface: register an interface with the wireless probe subsystem
+ * @dev: wprobe_iface structure describing the interface
+ */
+extern int __weak wprobe_add_iface(struct wprobe_iface *dev);
+
+/**
+ * wprobe_remove_iface: deregister an interface from the wireless probe subsystem
+ * @dev: wprobe_iface structure describing the interface
+ */
+extern void __weak wprobe_remove_iface(struct wprobe_iface *dev);
+
+/**
+ * wprobe_add_link: register a new wireless link
+ * @dev: wprobe_iface structure describing the interface
+ * @l: storage space for the wprobe_link structure
+ * @addr: mac address of the new link
+ *
+ * the entire wprobe_link structure is overwritten by this function call
+ */
+extern int __weak wprobe_add_link(struct wprobe_iface *dev, struct wprobe_link *l, const char *addr);
+
+/**
+ * wprobe_remove_link: deregister a previously registered wireless link
+ * @dev: wprobe_iface structure describing the interface
+ * @l: wprobe_link data structure
+ */
+extern void __weak wprobe_remove_link(struct wprobe_iface *dev, struct wprobe_link *l);
+
+/**
+ * wprobe_update_stats: update statistics after sampling values
+ * @dev: wprobe_iface structure describing the interface
+ * @l: wprobe_link data structure
+ *
+ * if l == NULL, then the stats for globals are updated
+ */
+extern void __weak wprobe_update_stats(struct wprobe_iface *dev, struct wprobe_link *l);
+
+#endif /* __KERNEL__ */
+
+#endif
diff --git a/package/wprobe/src/kernel/wprobe-core.c b/package/wprobe/src/kernel/wprobe-core.c
new file mode 100644
index 0000000000..03e9049464
--- /dev/null
+++ b/package/wprobe/src/kernel/wprobe-core.c
@@ -0,0 +1,669 @@
+/*
+ * wprobe-core.c: Wireless probe interface core
+ * Copyright (C) 2008-2009 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
+#include <linux/rculist.h>
+#else
+#include <linux/list.h>
+#endif
+#include <linux/skbuff.h>
+#include <linux/wprobe.h>
+#include <linux/math64.h>
+
+#define static
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
+#define list_for_each_rcu __list_for_each_rcu
+#endif
+
+static struct list_head wprobe_if;
+static spinlock_t wprobe_lock;
+
+static struct genl_family wprobe_fam = {
+	.id = GENL_ID_GENERATE,
+	.name = "wprobe",
+	.hdrsize = 0,
+	.version = 1,
+	/* only the first set of attributes is used for queries */
+	.maxattr = WPROBE_ATTR_ID,
+};
+
+static void wprobe_update_stats(struct wprobe_iface *dev, struct wprobe_link *l);
+
+int
+wprobe_add_link(struct wprobe_iface *s, struct wprobe_link *l, const char *addr)
+{
+	unsigned long flags;
+
+	INIT_LIST_HEAD(&l->list);
+	l->val = kzalloc(sizeof(struct wprobe_value) * s->n_link_items, GFP_ATOMIC);
+	if (!l->val)
+		return -ENOMEM;
+
+	l->iface = s;
+	memcpy(&l->addr, addr, ETH_ALEN);
+	spin_lock_irqsave(&wprobe_lock, flags);
+	list_add_tail_rcu(&l->list, &s->links);
+	spin_unlock_irqrestore(&wprobe_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(wprobe_add_link);
+
+void
+wprobe_remove_link(struct wprobe_iface *s, struct wprobe_link *l)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wprobe_lock, flags);
+	list_del_rcu(&l->list);
+	spin_unlock_irqrestore(&wprobe_lock, flags);
+	synchronize_rcu();
+	kfree(l->val);
+}
+EXPORT_SYMBOL(wprobe_remove_link);
+
+int
+wprobe_add_iface(struct wprobe_iface *s)
+{
+	unsigned long flags;
+	int vsize;
+
+	/* reset only wprobe private area */
+	memset(&s->list, 0, sizeof(struct wprobe_iface) - offsetof(struct wprobe_iface, list));
+
+	BUG_ON(!s->name);
+	INIT_LIST_HEAD(&s->list);
+	INIT_LIST_HEAD(&s->links);
+
+	vsize = max(s->n_link_items, s->n_global_items);
+	s->val = kzalloc(sizeof(struct wprobe_value) * vsize, GFP_ATOMIC);
+	if (!s->val)
+		goto error;
+
+	s->query_val = kzalloc(sizeof(struct wprobe_value) * vsize, GFP_ATOMIC);
+	if (!s->query_val)
+		goto error;
+
+	spin_lock_irqsave(&wprobe_lock, flags);
+	list_add_rcu(&s->list, &wprobe_if);
+	spin_unlock_irqrestore(&wprobe_lock, flags);
+
+	return 0;
+
+error:
+	if (s->val)
+		kfree(s->val);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(wprobe_add_iface);
+
+void
+wprobe_remove_iface(struct wprobe_iface *s)
+{
+	unsigned long flags;
+
+	BUG_ON(!list_empty(&s->links));
+
+	spin_lock_irqsave(&wprobe_lock, flags);
+	list_del_rcu(&s->list);
+	spin_unlock_irqrestore(&wprobe_lock, flags);
+
+	/* wait for all queries to finish before freeing the
+	 * temporary value storage buffer */
+	synchronize_rcu();
+
+	kfree(s->val);
+	kfree(s->query_val);
+}
+EXPORT_SYMBOL(wprobe_remove_iface);
+
+static struct wprobe_iface *
+wprobe_get_dev(struct nlattr *attr)
+{
+	struct wprobe_iface *dev = NULL;
+	struct wprobe_iface *p;
+	const char *name;
+	int i = 0;
+
+	if (!attr)
+		return NULL;
+
+	name = nla_data(attr);
+	list_for_each_entry_rcu(p, &wprobe_if, list) {
+		i++;
+		if (strcmp(name, p->name) != 0)
+			continue;
+
+		dev = p;
+		break;
+	}
+
+	return dev;
+}
+
+int
+wprobe_sync_data(struct wprobe_iface *dev, struct wprobe_link *l, bool query)
+{
+	struct wprobe_value *val;
+	unsigned long flags;
+	int n, err;
+
+	if (l) {
+		n = dev->n_link_items;
+		val = l->val;
+	} else {
+		n = dev->n_global_items;
+		val = dev->val;
+	}
+
+	spin_lock_irqsave(&dev->lock, flags);
+	err = dev->sync_data(dev, l, val, !query);
+	if (err)
+		goto done;
+
+	if (query)
+		memcpy(dev->query_val, val, sizeof(struct wprobe_value) * n);
+
+	wprobe_update_stats(dev, l);
+done:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL(wprobe_sync_data);
+
+void
+wprobe_update_stats(struct wprobe_iface *dev, struct wprobe_link *l)
+{
+	const struct wprobe_item *item;
+	struct wprobe_value *val;
+	int i, n;
+
+	if (l) {
+		n = dev->n_link_items;
+		item = dev->link_items;
+		val = l->val;
+	} else {
+		n = dev->n_global_items;
+		item = dev->global_items;
+		val = dev->val;
+	}
+
+	/* process statistics */
+	for (i = 0; i < n; i++) {
+		s64 v;
+
+		if (!val[i].pending)
+			continue;
+
+		val[i].n++;
+
+		switch(item[i].type) {
+		case WPROBE_VAL_S8:
+			v = val[i].S8;
+			break;
+		case WPROBE_VAL_S16:
+			v = val[i].S16;
+			break;
+		case WPROBE_VAL_S32:
+			v = val[i].S32;
+			break;
+		case WPROBE_VAL_S64:
+			v = val[i].S64;
+			break;
+		case WPROBE_VAL_U8:
+			v = val[i].U8;
+			break;
+		case WPROBE_VAL_U16:
+			v = val[i].U16;
+			break;
+		case WPROBE_VAL_U32:
+			v = val[i].U32;
+			break;
+		case WPROBE_VAL_U64:
+			v = val[i].U64;
+			break;
+		default:
+			continue;
+		}
+
+		val[i].s += v;
+		val[i].ss += v * v;
+		val[i].pending = false;
+	}
+}
+EXPORT_SYMBOL(wprobe_update_stats);
+
+static const struct nla_policy wprobe_policy[WPROBE_ATTR_ID+1] = {
+	[WPROBE_ATTR_INTERFACE] = { .type = NLA_NUL_STRING },
+	[WPROBE_ATTR_MAC] = { .type = NLA_STRING },
+	[WPROBE_ATTR_DURATION] = { .type = NLA_MSECS },
+	[WPROBE_ATTR_FLAGS] = { .type = NLA_U32 },
+	[WPROBE_ATTR_SCALE] = { .type = NLA_U32 },
+};
+
+static bool
+wprobe_check_ptr(struct list_head *list, struct list_head *ptr)
+{
+	struct list_head *p;
+
+	list_for_each_rcu(p, list) {
+		if (ptr == p)
+			return true;
+	}
+	return false;
+}
+
+static bool
+wprobe_send_item_value(struct sk_buff *msg, struct netlink_callback *cb,
+                       struct wprobe_iface *dev, struct wprobe_link *l,
+                       const struct wprobe_item *item,
+                       int i, u32 flags)
+{
+	struct genlmsghdr *hdr;
+	struct wprobe_value *val = dev->query_val;
+	u64 time = val[i].last - val[i].first;
+
+	hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+			&wprobe_fam, NLM_F_MULTI, WPROBE_CMD_GET_INFO);
+
+	NLA_PUT_U32(msg, WPROBE_ATTR_ID, i);
+	NLA_PUT_U32(msg, WPROBE_ATTR_FLAGS, flags);
+	NLA_PUT_U8(msg, WPROBE_ATTR_TYPE, item[i].type);
+	NLA_PUT_U64(msg, WPROBE_ATTR_DURATION, time);
+
+	switch(item[i].type) {
+	case WPROBE_VAL_S8:
+	case WPROBE_VAL_U8:
+		NLA_PUT_U8(msg, item[i].type, val[i].U8);
+		break;
+	case WPROBE_VAL_S16:
+	case WPROBE_VAL_U16:
+		NLA_PUT_U16(msg, item[i].type, val[i].U16);
+		break;
+	case WPROBE_VAL_S32:
+	case WPROBE_VAL_U32:
+		NLA_PUT_U32(msg, item[i].type, val[i].U32);
+		break;
+	case WPROBE_VAL_S64:
+	case WPROBE_VAL_U64:
+		NLA_PUT_U64(msg, item[i].type, val[i].U64);
+		break;
+	case WPROBE_VAL_STRING:
+		if (val[i].STRING)
+			NLA_PUT_STRING(msg, item[i].type, val[i].STRING);
+		else
+			NLA_PUT_STRING(msg, item[i].type, "");
+		/* bypass avg/stdev */
+		goto done;
+	default:
+		/* skip unknown values */
+		goto done;
+	}
+	if (item[i].flags & WPROBE_F_KEEPSTAT) {
+		NLA_PUT_U64(msg, WPROBE_VAL_SUM, val[i].s);
+		NLA_PUT_U64(msg, WPROBE_VAL_SUM_SQ, val[i].ss);
+		NLA_PUT_U32(msg, WPROBE_VAL_SAMPLES, (u32) val[i].n);
+	}
+done:
+	genlmsg_end(msg, hdr);
+	return true;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return false;
+}
+
+static bool
+wprobe_send_item_info(struct sk_buff *msg, struct netlink_callback *cb,
+                       struct wprobe_iface *dev,
+                       const struct wprobe_item *item, int i)
+{
+	struct genlmsghdr *hdr;
+
+	hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+			&wprobe_fam, NLM_F_MULTI, WPROBE_CMD_GET_LIST);
+
+	if ((i == 0) && (dev->addr != NULL))
+		NLA_PUT(msg, WPROBE_ATTR_MAC, 6, dev->addr);
+	NLA_PUT_U32(msg, WPROBE_ATTR_ID, (u32) i);
+	NLA_PUT_STRING(msg, WPROBE_ATTR_NAME, item[i].name);
+	NLA_PUT_U8(msg, WPROBE_ATTR_TYPE, item[i].type);
+	NLA_PUT_U32(msg, WPROBE_ATTR_FLAGS, item[i].flags);
+	genlmsg_end(msg, hdr);
+	return true;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return false;
+}
+
+
+static struct wprobe_link *
+wprobe_find_link(struct wprobe_iface *dev, const char *mac)
+{
+	struct wprobe_link *l;
+
+	list_for_each_entry_rcu(l, &dev->links, list) {
+		if (!memcmp(l->addr, mac, 6))
+			return l;
+	}
+	return NULL;
+}
+
+static bool
+wprobe_dump_link(struct sk_buff *msg, struct wprobe_link *l, struct netlink_callback *cb)
+{
+	struct genlmsghdr *hdr;
+
+	hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+			&wprobe_fam, NLM_F_MULTI, WPROBE_CMD_GET_LINKS);
+	if (!hdr)
+		return false;
+
+	NLA_PUT(msg, WPROBE_ATTR_MAC, 6, l->addr);
+	genlmsg_end(msg, hdr);
+	return true;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return false;
+}
+
+static int
+wprobe_dump_links(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct wprobe_iface *dev = (struct wprobe_iface *)cb->args[0];
+	struct wprobe_link *l;
+	int err = 0;
+	int i = 0;
+
+	if (!dev) {
+		err = nlmsg_parse(cb->nlh, GENL_HDRLEN + wprobe_fam.hdrsize,
+				wprobe_fam.attrbuf, wprobe_fam.maxattr, wprobe_policy);
+		if (err)
+			goto done;
+
+		dev = wprobe_get_dev(wprobe_fam.attrbuf[WPROBE_ATTR_INTERFACE]);
+		if (!dev) {
+			err = -ENODEV;
+			goto done;
+		}
+
+		cb->args[0] = (long) dev;
+	} else {
+		if (!wprobe_check_ptr(&wprobe_if, &dev->list)) {
+			err = -ENODEV;
+			goto done;
+		}
+	}
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(l, &dev->links, list) {
+		if (i < cb->args[1])
+			continue;
+
+		if (unlikely(!wprobe_dump_link(skb, l, cb)))
+			break;
+
+		i++;
+	}
+	cb->args[1] = i;
+	rcu_read_unlock();
+	err = skb->len;
+done:
+	return err;
+}
+static void
+wprobe_scale_stats(const struct wprobe_item *item, struct wprobe_value *val, int n, u32 flags)
+{
+	u32 scale = 0;
+	int i;
+
+	for (i = 0; i < n; i++) {
+		if (!(item[i].flags & WPROBE_F_KEEPSTAT))
+			continue;
+
+		/* reset statistics, if requested */
+		if (flags & WPROBE_F_RESET)
+			scale = val[i].n;
+		else if (wprobe_fam.attrbuf[WPROBE_ATTR_SCALE])
+			scale = nla_get_u32(wprobe_fam.attrbuf[WPROBE_ATTR_SCALE]);
+
+		if ((scale > 0) && (val[i].n >= scale)) {
+			val[i].s = div_s64(val[i].s, scale);
+			val[i].ss = div_s64(val[i].ss, scale);
+			val[i].n /= scale;
+		}
+	}
+}
+
+#define WPROBE_F_LINK (1 << 31) /* for internal use */
+static int
+wprobe_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct wprobe_iface *dev = (struct wprobe_iface *)cb->args[0];
+	struct wprobe_link *l = (struct wprobe_link *)cb->args[1];
+	struct wprobe_value *val;
+	const struct wprobe_item *item;
+	struct genlmsghdr *hdr;
+	unsigned long flags;
+	int cmd, n, i = cb->args[3];
+	u32	vflags = cb->args[2];
+	int err = 0;
+
+	hdr = (struct genlmsghdr *)nlmsg_data(cb->nlh);
+	cmd = hdr->cmd;
+
+	/* since the attribute value list might be too big for a single netlink
+	 * message, the device, link and offset get stored in the netlink callback.
+	 * if this is the first request, we need to do the full lookup for the device.
+	 *
+	 * access to the device and link structure is synchronized through rcu.
+	 */
+	rcu_read_lock();
+	if (!dev) {
+		err = nlmsg_parse(cb->nlh, GENL_HDRLEN + wprobe_fam.hdrsize,
+				wprobe_fam.attrbuf, wprobe_fam.maxattr, wprobe_policy);
+		if (err)
+			goto done;
+
+		err = -ENOENT;
+		dev = wprobe_get_dev(wprobe_fam.attrbuf[WPROBE_ATTR_INTERFACE]);
+		if (!dev)
+			goto done;
+
+		if (cmd == WPROBE_CMD_GET_INFO) {
+			if (wprobe_fam.attrbuf[WPROBE_ATTR_MAC]) {
+				l = wprobe_find_link(dev, nla_data(wprobe_fam.attrbuf[WPROBE_ATTR_MAC]));
+				if (!l)
+					goto done;
+
+				vflags = l->flags;
+			}
+
+			if (l) {
+				item = dev->link_items;
+				n = dev->n_link_items;
+				val = l->val;
+			} else {
+				item = dev->global_items;
+				n = dev->n_global_items;
+				val = dev->val;
+			}
+
+			/* sync data and move to temp storage for the query */
+			spin_lock_irqsave(&dev->lock, flags);
+			err = wprobe_sync_data(dev, l, true);
+			if (!err)
+				memcpy(dev->query_val, val, n * sizeof(struct wprobe_value));
+			wprobe_scale_stats(item, val, n, flags);
+			spin_unlock_irqrestore(&dev->lock, flags);
+
+			if (err)
+				goto done;
+		}
+
+		if (wprobe_fam.attrbuf[WPROBE_ATTR_FLAGS])
+			vflags |= nla_get_u32(wprobe_fam.attrbuf[WPROBE_ATTR_FLAGS]);
+
+		if (wprobe_fam.attrbuf[WPROBE_ATTR_MAC])
+			vflags |= WPROBE_F_LINK;
+
+		cb->args[0] = (long) dev;
+		cb->args[1] = (long) l;
+		cb->args[2] = vflags;
+		cb->args[3] = 0;
+	} else {
+		/* when pulling pointers from the callback, validate them
+		 * against the list using rcu to make sure that we won't
+		 * dereference pointers to free'd memory after the last
+		 * grace period */
+		err = -ENOENT;
+		if (!wprobe_check_ptr(&wprobe_if, &dev->list))
+			goto done;
+
+		if (l && !wprobe_check_ptr(&dev->links, &l->list))
+			goto done;
+	}
+
+	if (vflags & WPROBE_F_LINK) {
+		item = dev->link_items;
+		n = dev->n_link_items;
+	} else {
+		item = dev->global_items;
+		n = dev->n_global_items;
+	}
+
+	err = 0;
+	switch(cmd) {
+	case WPROBE_CMD_GET_INFO:
+		while (i < n) {
+			if (!wprobe_send_item_value(skb, cb, dev, l, item, i, vflags))
+				break;
+			i++;
+		}
+		break;
+	case WPROBE_CMD_GET_LIST:
+		while (i < n) {
+			if (!wprobe_send_item_info(skb, cb, dev, item, i))
+				break;
+			i++;
+		}
+		break;
+	default:
+		err = -EINVAL;
+		goto done;
+	}
+	cb->args[3] = i;
+	err = skb->len;
+
+done:
+	rcu_read_unlock();
+	return err;
+}
+#undef WPROBE_F_LINK
+
+static int
+wprobe_measure(struct sk_buff *skb, struct genl_info *info)
+{
+	struct wprobe_iface *dev;
+	struct wprobe_link *l = NULL;
+	int err = -ENOENT;
+
+	rcu_read_lock();
+	dev = wprobe_get_dev(info->attrs[WPROBE_ATTR_INTERFACE]);
+	if (!dev)
+		goto done;
+
+	if (info->attrs[WPROBE_ATTR_MAC]) {
+		l = wprobe_find_link(dev, nla_data(wprobe_fam.attrbuf[WPROBE_ATTR_MAC]));
+		if (!l)
+			goto done;
+	}
+
+	err = wprobe_sync_data(dev, l, false);
+
+done:
+	rcu_read_unlock();
+	return err;
+}
+
+static struct genl_ops wprobe_ops[] = {
+	{
+		.cmd = WPROBE_CMD_GET_INFO,
+		.dumpit = wprobe_dump_info,
+		.policy = wprobe_policy,
+	},
+	{
+		.cmd = WPROBE_CMD_GET_LIST,
+		.dumpit = wprobe_dump_info,
+		.policy = wprobe_policy,
+	},
+	{
+		.cmd = WPROBE_CMD_MEASURE,
+		.doit = wprobe_measure,
+		.policy = wprobe_policy,
+	},
+	{
+		.cmd = WPROBE_CMD_GET_LINKS,
+		.dumpit = wprobe_dump_links,
+		.policy = wprobe_policy,
+	}
+};
+
+static void __exit
+wprobe_exit(void)
+{
+	BUG_ON(!list_empty(&wprobe_if));
+	genl_unregister_family(&wprobe_fam);
+}
+
+
+static int __init
+wprobe_init(void)
+{
+	int i, err;
+
+	spin_lock_init(&wprobe_lock);
+	INIT_LIST_HEAD(&wprobe_if);
+
+	err = genl_register_family(&wprobe_fam);
+	if (err)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(wprobe_ops); i++) {
+		err = genl_register_ops(&wprobe_fam, &wprobe_ops[i]);
+		if (err)
+			goto error;
+	}
+
+	return 0;
+
+error:
+	genl_unregister_family(&wprobe_fam);
+	return err;
+}
+
+module_init(wprobe_init);
+module_exit(wprobe_exit);
+MODULE_LICENSE("GPL");
+
diff --git a/package/wprobe/src/kernel/wprobe-dummy.c b/package/wprobe/src/kernel/wprobe-dummy.c
new file mode 100644
index 0000000000..4231223e0e
--- /dev/null
+++ b/package/wprobe/src/kernel/wprobe-dummy.c
@@ -0,0 +1,96 @@
+/*
+ * wprobe-core.c: Wireless probe interface dummy driver
+ * Copyright (C) 2008-2009 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/random.h>
+#include <linux/wprobe.h>
+
+static const char local_addr[] = "\x00\x13\x37\xba\xbe\x00";
+
+enum dummy_global_values {
+	DUMMY_GLOBAL_MEDIUM_BUSY
+};
+enum dummy_link_values {
+	DUMMY_LINK_SNR
+};
+
+struct wprobe_item dummy_perlink[] = {
+	[DUMMY_LINK_SNR] = {
+		.name = "snr",
+		.type = WPROBE_VAL_U8,
+		.flags = WPROBE_F_KEEPSTAT,
+	},
+};
+
+struct wprobe_item dummy_globals[] = {
+	[DUMMY_GLOBAL_MEDIUM_BUSY] = {
+		.name = "medium_busy",
+		.type = WPROBE_VAL_U8,
+		.flags = WPROBE_F_KEEPSTAT,
+	}
+};
+
+int dummy_sync(struct wprobe_iface *dev, struct wprobe_link *l, struct wprobe_value *val, bool measure)
+{
+	u8 intval = 0;
+
+	get_random_bytes(&intval, 1);
+	if (l) {
+		WPROBE_FILL_BEGIN(val, dummy_perlink);
+		WPROBE_SET(DUMMY_LINK_SNR, U8, (intval % 40));
+		WPROBE_FILL_END();
+	} else {
+		WPROBE_FILL_BEGIN(val, dummy_globals);
+		WPROBE_SET(DUMMY_GLOBAL_MEDIUM_BUSY, U8, (intval % 100));
+		WPROBE_FILL_END();
+	}
+	return 0;
+}
+
+static struct wprobe_iface dummy_dev = {
+	.name = "dummy",
+	.addr = local_addr,
+	.link_items = dummy_perlink,
+	.n_link_items = ARRAY_SIZE(dummy_perlink),
+	.global_items = dummy_globals,
+	.n_global_items = ARRAY_SIZE(dummy_globals),
+	.sync_data = dummy_sync,
+};
+
+static struct wprobe_link dummy_link;
+
+static int __init
+wprobe_dummy_init(void)
+{
+	wprobe_add_iface(&dummy_dev);
+	wprobe_add_link(&dummy_dev, &dummy_link, "\x00\x13\x37\xda\xda\x00");
+	return 0;
+}
+
+static void __exit
+wprobe_dummy_exit(void)
+{
+	wprobe_remove_link(&dummy_dev, &dummy_link);
+	wprobe_remove_iface(&dummy_dev);
+}
+
+module_init(wprobe_dummy_init);
+module_exit(wprobe_dummy_exit);
+
+MODULE_LICENSE("GPL");