diff --git a/include/linux/netfilter/xt_qtaguid.h b/include/linux/netfilter/xt_qtaguid.h
new file mode 100644
index 0000000..ca60fbd
--- /dev/null
+++ b/include/linux/netfilter/xt_qtaguid.h
@@ -0,0 +1,13 @@
+#ifndef _XT_QTAGUID_MATCH_H
+#define _XT_QTAGUID_MATCH_H
+
+/* For now we just replace the xt_owner.
+ * FIXME: make iptables aware of qtaguid. */
+#include <linux/netfilter/xt_owner.h>
+
+#define XT_QTAGUID_UID    XT_OWNER_UID
+#define XT_QTAGUID_GID    XT_OWNER_GID
+#define XT_QTAGUID_SOCKET XT_OWNER_SOCKET
+#define xt_qtaguid_match_info xt_owner_match_info
+
+#endif /* _XT_QTAGUID_MATCH_H */
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index c19b214..7f26f01 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -1003,6 +1003,8 @@ config NETFILTER_XT_MATCH_OWNER
 	based on who created the socket: the user or group. It is also
 	possible to check whether a socket actually exists.
 
+	Conflicts with '"quota, tag, uid" match'
+
 config NETFILTER_XT_MATCH_POLICY
 	tristate 'IPsec "policy" match support'
 	depends on XFRM
@@ -1036,6 +1038,22 @@ config NETFILTER_XT_MATCH_PKTTYPE
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_QTAGUID
+	bool '"quota, tag, owner" match and stats support'
+        depends on NETFILTER_XT_MATCH_SOCKET
+	depends on NETFILTER_XT_MATCH_OWNER=n
+	help
+	  This option replaces the `owner' match. In addition to matching
+	  on uid, it keeps stats based on a tag assigned to a socket.
+	  The full tag is comprised of a UID and an accounting tag.
+	  The tags are assignable to sockets from user space (e.g. a download
+	  manager can assign the socket to another UID for accounting).
+	  Stats and control are done via /proc/net/xt_qtaguid/.
+	  It replaces owner as it takes the same arguments, but should
+	  really be recognized by the iptables tool.
+
+	  If unsure, say `N'.
+
 config NETFILTER_XT_MATCH_QUOTA
 	tristate '"quota" match support'
 	depends on NETFILTER_ADVANCED
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 1c5160f..1d15e36 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -105,6 +105,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_OWNER) += xt_owner.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PKTTYPE) += xt_pkttype.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_POLICY) += xt_policy.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_QTAGUID) += xt_qtaguid_print.o xt_qtaguid.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_QUOTA) += xt_quota.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_RATEEST) += xt_rateest.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_REALM) += xt_realm.o
diff --git a/net/netfilter/xt_qtaguid.c b/net/netfilter/xt_qtaguid.c
new file mode 100644
index 0000000..7c4ac46
--- /dev/null
+++ b/net/netfilter/xt_qtaguid.c
@@ -0,0 +1,2775 @@
+/*
+ * Kernel iptables module to track stats for packets based on user tags.
+ *
+ * (C) 2011 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * There are run-time debug flags enabled via the debug_mask module param, or
+ * via the DEFAULT_DEBUG_MASK. See xt_qtaguid_internal.h.
+ */
+#define DEBUG
+
+#include <linux/file.h>
+#include <linux/inetdevice.h>
+#include <linux/module.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_qtaguid.h>
+#include <linux/skbuff.h>
+#include <linux/workqueue.h>
+#include <net/addrconf.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+
+#include <linux/netfilter/xt_socket.h>
+#include "xt_qtaguid_internal.h"
+#include "xt_qtaguid_print.h"
+
+/*
+ * We only use the xt_socket funcs within a similar context to avoid unexpected
+ * return values.
+ */
+#define XT_SOCKET_SUPPORTED_HOOKS \
+	((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN))
+
+
+static const char *module_procdirname = "xt_qtaguid";
+static struct proc_dir_entry *xt_qtaguid_procdir;
+
+static unsigned int proc_iface_perms = S_IRUGO;
+module_param_named(iface_perms, proc_iface_perms, uint, S_IRUGO | S_IWUSR);
+
+static struct proc_dir_entry *xt_qtaguid_stats_file;
+static unsigned int proc_stats_perms = S_IRUGO;
+module_param_named(stats_perms, proc_stats_perms, uint, S_IRUGO | S_IWUSR);
+
+static struct proc_dir_entry *xt_qtaguid_ctrl_file;
+static unsigned int proc_ctrl_perms = S_IRUGO | S_IWUSR;
+module_param_named(ctrl_perms, proc_ctrl_perms, uint, S_IRUGO | S_IWUSR);
+
+/* 0 means, don't limit anybody */
+static gid_t proc_stats_readall_gid;
+static gid_t proc_ctrl_write_gid;
+module_param_named(stats_readall_gid, proc_stats_readall_gid, uint,
+		   S_IRUGO | S_IWUSR);
+module_param_named(ctrl_write_gid, proc_ctrl_write_gid, uint,
+		   S_IRUGO | S_IWUSR);
+
+/*
+ * Limit the number of active tags (via socket tags) for a given UID.
+ * Multiple processes could share the UID.
+ */
+static int max_sock_tags = DEFAULT_MAX_SOCK_TAGS;
+module_param(max_sock_tags, int, S_IRUGO | S_IWUSR);
+
+/*
+ * After the kernel has initiallized this module, it is still possible
+ * to make it passive.
+ * Setting passive to Y:
+ *  - the iface stats handling will not act on notifications.
+ *  - iptables matches will never match.
+ *  - ctrl commands silently succeed.
+ *  - stats are always empty.
+ * This is mostly usefull when a bug is suspected.
+ */
+static bool module_passive;
+module_param_named(passive, module_passive, bool, S_IRUGO | S_IWUSR);
+
+/*
+ * Control how qtaguid data is tracked per proc/uid.
+ * Setting tag_tracking_passive to Y:
+ *  - don't create proc specific structs to track tags
+ *  - don't check that active tag stats exceed some limits.
+ *  - don't clean up socket tags on process exits.
+ * This is mostly usefull when a bug is suspected.
+ */
+static bool qtu_proc_handling_passive;
+module_param_named(tag_tracking_passive, qtu_proc_handling_passive, bool,
+		   S_IRUGO | S_IWUSR);
+
+#define QTU_DEV_NAME "xt_qtaguid"
+
+uint qtaguid_debug_mask = DEFAULT_DEBUG_MASK;
+module_param_named(debug_mask, qtaguid_debug_mask, uint, S_IRUGO | S_IWUSR);
+
+/*---------------------------------------------------------------------------*/
+static const char *iface_stat_procdirname = "iface_stat";
+static struct proc_dir_entry *iface_stat_procdir;
+static const char *iface_stat_all_procfilename = "iface_stat_all";
+static struct proc_dir_entry *iface_stat_all_procfile;
+
+/*
+ * Ordering of locks:
+ *  outer locks:
+ *    iface_stat_list_lock
+ *    sock_tag_list_lock
+ *  inner locks:
+ *    uid_tag_data_tree_lock
+ *    tag_counter_set_list_lock
+ * Notice how sock_tag_list_lock is held sometimes when uid_tag_data_tree_lock
+ * is acquired.
+ *
+ * Call tree with all lock holders as of 2011-09-25:
+ *
+ * iface_stat_all_proc_read()
+ *   iface_stat_list_lock
+ *     (struct iface_stat)
+ *
+ * qtaguid_ctrl_proc_read()
+ *   sock_tag_list_lock
+ *     (sock_tag_tree)
+ *     (struct proc_qtu_data->sock_tag_list)
+ *   prdebug_full_state()
+ *     sock_tag_list_lock
+ *       (sock_tag_tree)
+ *     uid_tag_data_tree_lock
+ *       (uid_tag_data_tree)
+ *       (proc_qtu_data_tree)
+ *     iface_stat_list_lock
+ *
+ * qtaguid_stats_proc_read()
+ *   iface_stat_list_lock
+ *     struct iface_stat->tag_stat_list_lock
+ *
+ * qtudev_open()
+ *   uid_tag_data_tree_lock
+ *
+ * qtudev_release()
+ *   sock_tag_data_list_lock
+ *     uid_tag_data_tree_lock
+ *   prdebug_full_state()
+ *     sock_tag_list_lock
+ *     uid_tag_data_tree_lock
+ *     iface_stat_list_lock
+ *
+ * iface_netdev_event_handler()
+ *   iface_stat_create()
+ *     iface_stat_list_lock
+ *   iface_stat_update()
+ *     iface_stat_list_lock
+ *
+ * iface_inetaddr_event_handler()
+ *   iface_stat_create()
+ *     iface_stat_list_lock
+ *   iface_stat_update()
+ *     iface_stat_list_lock
+ *
+ * iface_inet6addr_event_handler()
+ *   iface_stat_create_ipv6()
+ *     iface_stat_list_lock
+ *   iface_stat_update()
+ *     iface_stat_list_lock
+ *
+ * qtaguid_mt()
+ *   account_for_uid()
+ *     if_tag_stat_update()
+ *       get_sock_stat()
+ *         sock_tag_list_lock
+ *       struct iface_stat->tag_stat_list_lock
+ *         tag_stat_update()
+ *           get_active_counter_set()
+ *             tag_counter_set_list_lock
+ *         tag_stat_update()
+ *           get_active_counter_set()
+ *             tag_counter_set_list_lock
+ *
+ *
+ * qtaguid_ctrl_parse()
+ *   ctrl_cmd_delete()
+ *     sock_tag_list_lock
+ *     tag_counter_set_list_lock
+ *     iface_stat_list_lock
+ *       struct iface_stat->tag_stat_list_lock
+ *     uid_tag_data_tree_lock
+ *   ctrl_cmd_counter_set()
+ *     tag_counter_set_list_lock
+ *   ctrl_cmd_tag()
+ *     sock_tag_list_lock
+ *       (sock_tag_tree)
+ *       get_tag_ref()
+ *         uid_tag_data_tree_lock
+ *           (uid_tag_data_tree)
+ *       uid_tag_data_tree_lock
+ *         (proc_qtu_data_tree)
+ *   ctrl_cmd_untag()
+ *     sock_tag_list_lock
+ *     uid_tag_data_tree_lock
+ *
+ */
+static LIST_HEAD(iface_stat_list);
+static DEFINE_SPINLOCK(iface_stat_list_lock);
+
+static struct rb_root sock_tag_tree = RB_ROOT;
+static DEFINE_SPINLOCK(sock_tag_list_lock);
+
+static struct rb_root tag_counter_set_tree = RB_ROOT;
+static DEFINE_SPINLOCK(tag_counter_set_list_lock);
+
+static struct rb_root uid_tag_data_tree = RB_ROOT;
+static DEFINE_SPINLOCK(uid_tag_data_tree_lock);
+
+static struct rb_root proc_qtu_data_tree = RB_ROOT;
+/* No proc_qtu_data_tree_lock; use uid_tag_data_tree_lock */
+
+static struct qtaguid_event_counts qtu_events;
+/*----------------------------------------------*/
+static bool can_manipulate_uids(void)
+{
+	/* root pwnd */
+	return unlikely(!current_fsuid()) || unlikely(!proc_ctrl_write_gid)
+		|| in_egroup_p(proc_ctrl_write_gid);
+}
+
+static bool can_impersonate_uid(uid_t uid)
+{
+	return uid == current_fsuid() || can_manipulate_uids();
+}
+
+static bool can_read_other_uid_stats(uid_t uid)
+{
+	/* root pwnd */
+	return unlikely(!current_fsuid()) || uid == current_fsuid()
+		|| unlikely(!proc_stats_readall_gid)
+		|| in_egroup_p(proc_stats_readall_gid);
+}
+
+static inline void dc_add_byte_packets(struct data_counters *counters, int set,
+				  enum ifs_tx_rx direction,
+				  enum ifs_proto ifs_proto,
+				  int bytes,
+				  int packets)
+{
+	counters->bpc[set][direction][ifs_proto].bytes += bytes;
+	counters->bpc[set][direction][ifs_proto].packets += packets;
+}
+
+static inline uint64_t dc_sum_bytes(struct data_counters *counters,
+				    int set,
+				    enum ifs_tx_rx direction)
+{
+	return counters->bpc[set][direction][IFS_TCP].bytes
+		+ counters->bpc[set][direction][IFS_UDP].bytes
+		+ counters->bpc[set][direction][IFS_PROTO_OTHER].bytes;
+}
+
+static inline uint64_t dc_sum_packets(struct data_counters *counters,
+				      int set,
+				      enum ifs_tx_rx direction)
+{
+	return counters->bpc[set][direction][IFS_TCP].packets
+		+ counters->bpc[set][direction][IFS_UDP].packets
+		+ counters->bpc[set][direction][IFS_PROTO_OTHER].packets;
+}
+
+static struct tag_node *tag_node_tree_search(struct rb_root *root, tag_t tag)
+{
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		struct tag_node *data = rb_entry(node, struct tag_node, node);
+		int result;
+		RB_DEBUG("qtaguid: tag_node_tree_search(0x%llx): "
+			 " node=%p data=%p\n", tag, node, data);
+		result = tag_compare(tag, data->tag);
+		RB_DEBUG("qtaguid: tag_node_tree_search(0x%llx): "
+			 " data.tag=0x%llx (uid=%u) res=%d\n",
+			 tag, data->tag, get_uid_from_tag(data->tag), result);
+		if (result < 0)
+			node = node->rb_left;
+		else if (result > 0)
+			node = node->rb_right;
+		else
+			return data;
+	}
+	return NULL;
+}
+
+static void tag_node_tree_insert(struct tag_node *data, struct rb_root *root)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+
+	/* Figure out where to put new node */
+	while (*new) {
+		struct tag_node *this = rb_entry(*new, struct tag_node,
+						 node);
+		int result = tag_compare(data->tag, this->tag);
+		RB_DEBUG("qtaguid: %s(): tag=0x%llx"
+			 " (uid=%u)\n", __func__,
+			 this->tag,
+			 get_uid_from_tag(this->tag));
+		parent = *new;
+		if (result < 0)
+			new = &((*new)->rb_left);
+		else if (result > 0)
+			new = &((*new)->rb_right);
+		else
+			BUG();
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&data->node, parent, new);
+	rb_insert_color(&data->node, root);
+}
+
+static void tag_stat_tree_insert(struct tag_stat *data, struct rb_root *root)
+{
+	tag_node_tree_insert(&data->tn, root);
+}
+
+static struct tag_stat *tag_stat_tree_search(struct rb_root *root, tag_t tag)
+{
+	struct tag_node *node = tag_node_tree_search(root, tag);
+	if (!node)
+		return NULL;
+	return rb_entry(&node->node, struct tag_stat, tn.node);
+}
+
+static void tag_counter_set_tree_insert(struct tag_counter_set *data,
+					struct rb_root *root)
+{
+	tag_node_tree_insert(&data->tn, root);
+}
+
+static struct tag_counter_set *tag_counter_set_tree_search(struct rb_root *root,
+							   tag_t tag)
+{
+	struct tag_node *node = tag_node_tree_search(root, tag);
+	if (!node)
+		return NULL;
+	return rb_entry(&node->node, struct tag_counter_set, tn.node);
+
+}
+
+static void tag_ref_tree_insert(struct tag_ref *data, struct rb_root *root)
+{
+	tag_node_tree_insert(&data->tn, root);
+}
+
+static struct tag_ref *tag_ref_tree_search(struct rb_root *root, tag_t tag)
+{
+	struct tag_node *node = tag_node_tree_search(root, tag);
+	if (!node)
+		return NULL;
+	return rb_entry(&node->node, struct tag_ref, tn.node);
+}
+
+static struct sock_tag *sock_tag_tree_search(struct rb_root *root,
+					     const struct sock *sk)
+{
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		struct sock_tag *data = rb_entry(node, struct sock_tag,
+						 sock_node);
+		if (sk < data->sk)
+			node = node->rb_left;
+		else if (sk > data->sk)
+			node = node->rb_right;
+		else
+			return data;
+	}
+	return NULL;
+}
+
+static void sock_tag_tree_insert(struct sock_tag *data, struct rb_root *root)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+
+	/* Figure out where to put new node */
+	while (*new) {
+		struct sock_tag *this = rb_entry(*new, struct sock_tag,
+						 sock_node);
+		parent = *new;
+		if (data->sk < this->sk)
+			new = &((*new)->rb_left);
+		else if (data->sk > this->sk)
+			new = &((*new)->rb_right);
+		else
+			BUG();
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&data->sock_node, parent, new);
+	rb_insert_color(&data->sock_node, root);
+}
+
+static void sock_tag_tree_erase(struct rb_root *st_to_free_tree)
+{
+	struct rb_node *node;
+	struct sock_tag *st_entry;
+
+	node = rb_first(st_to_free_tree);
+	while (node) {
+		st_entry = rb_entry(node, struct sock_tag, sock_node);
+		node = rb_next(node);
+		CT_DEBUG("qtaguid: %s(): "
+			 "erase st: sk=%p tag=0x%llx (uid=%u)\n", __func__,
+			 st_entry->sk,
+			 st_entry->tag,
+			 get_uid_from_tag(st_entry->tag));
+		rb_erase(&st_entry->sock_node, st_to_free_tree);
+		sockfd_put(st_entry->socket);
+		kfree(st_entry);
+	}
+}
+
+static struct proc_qtu_data *proc_qtu_data_tree_search(struct rb_root *root,
+						       const pid_t pid)
+{
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		struct proc_qtu_data *data = rb_entry(node,
+						      struct proc_qtu_data,
+						      node);
+		if (pid < data->pid)
+			node = node->rb_left;
+		else if (pid > data->pid)
+			node = node->rb_right;
+		else
+			return data;
+	}
+	return NULL;
+}
+
+static void proc_qtu_data_tree_insert(struct proc_qtu_data *data,
+				      struct rb_root *root)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+
+	/* Figure out where to put new node */
+	while (*new) {
+		struct proc_qtu_data *this = rb_entry(*new,
+						      struct proc_qtu_data,
+						      node);
+		parent = *new;
+		if (data->pid < this->pid)
+			new = &((*new)->rb_left);
+		else if (data->pid > this->pid)
+			new = &((*new)->rb_right);
+		else
+			BUG();
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&data->node, parent, new);
+	rb_insert_color(&data->node, root);
+}
+
+static void uid_tag_data_tree_insert(struct uid_tag_data *data,
+				     struct rb_root *root)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+
+	/* Figure out where to put new node */
+	while (*new) {
+		struct uid_tag_data *this = rb_entry(*new,
+						     struct uid_tag_data,
+						     node);
+		parent = *new;
+		if (data->uid < this->uid)
+			new = &((*new)->rb_left);
+		else if (data->uid > this->uid)
+			new = &((*new)->rb_right);
+		else
+			BUG();
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&data->node, parent, new);
+	rb_insert_color(&data->node, root);
+}
+
+static struct uid_tag_data *uid_tag_data_tree_search(struct rb_root *root,
+						     uid_t uid)
+{
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		struct uid_tag_data *data = rb_entry(node,
+						     struct uid_tag_data,
+						     node);
+		if (uid < data->uid)
+			node = node->rb_left;
+		else if (uid > data->uid)
+			node = node->rb_right;
+		else
+			return data;
+	}
+	return NULL;
+}
+
+/*
+ * Allocates a new uid_tag_data struct if needed.
+ * Returns a pointer to the found or allocated uid_tag_data.
+ * Returns a PTR_ERR on failures, and lock is not held.
+ * If found is not NULL:
+ *   sets *found to true if not allocated.
+ *   sets *found to false if allocated.
+ */
+struct uid_tag_data *get_uid_data(uid_t uid, bool *found_res)
+{
+	struct uid_tag_data *utd_entry;
+
+	/* Look for top level uid_tag_data for the UID */
+	utd_entry = uid_tag_data_tree_search(&uid_tag_data_tree, uid);
+	DR_DEBUG("qtaguid: get_uid_data(%u) utd=%p\n", uid, utd_entry);
+
+	if (found_res)
+		*found_res = utd_entry;
+	if (utd_entry)
+		return utd_entry;
+
+	utd_entry = kzalloc(sizeof(*utd_entry), GFP_ATOMIC);
+	if (!utd_entry) {
+		pr_err("qtaguid: get_uid_data(%u): "
+		       "tag data alloc failed\n", uid);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	utd_entry->uid = uid;
+	utd_entry->tag_ref_tree = RB_ROOT;
+	uid_tag_data_tree_insert(utd_entry, &uid_tag_data_tree);
+	DR_DEBUG("qtaguid: get_uid_data(%u) new utd=%p\n", uid, utd_entry);
+	return utd_entry;
+}
+
+/* Never returns NULL. Either PTR_ERR or a valid ptr. */
+static struct tag_ref *new_tag_ref(tag_t new_tag,
+				   struct uid_tag_data *utd_entry)
+{
+	struct tag_ref *tr_entry;
+	int res;
+
+	if (utd_entry->num_active_tags + 1 > max_sock_tags) {
+		pr_info("qtaguid: new_tag_ref(0x%llx): "
+			"tag ref alloc quota exceeded. max=%d\n",
+			new_tag, max_sock_tags);
+		res = -EMFILE;
+		goto err_res;
+
+	}
+
+	tr_entry = kzalloc(sizeof(*tr_entry), GFP_ATOMIC);
+	if (!tr_entry) {
+		pr_err("qtaguid: new_tag_ref(0x%llx): "
+		       "tag ref alloc failed\n",
+		       new_tag);
+		res = -ENOMEM;
+		goto err_res;
+	}
+	tr_entry->tn.tag = new_tag;
+	/* tr_entry->num_sock_tags  handled by caller */
+	utd_entry->num_active_tags++;
+	tag_ref_tree_insert(tr_entry, &utd_entry->tag_ref_tree);
+	DR_DEBUG("qtaguid: new_tag_ref(0x%llx): "
+		 " inserted new tag ref %p\n",
+		 new_tag, tr_entry);
+	return tr_entry;
+
+err_res:
+	return ERR_PTR(res);
+}
+
+static struct tag_ref *lookup_tag_ref(tag_t full_tag,
+				      struct uid_tag_data **utd_res)
+{
+	struct uid_tag_data *utd_entry;
+	struct tag_ref *tr_entry;
+	bool found_utd;
+	uid_t uid = get_uid_from_tag(full_tag);
+
+	DR_DEBUG("qtaguid: lookup_tag_ref(tag=0x%llx (uid=%u))\n",
+		 full_tag, uid);
+
+	utd_entry = get_uid_data(uid, &found_utd);
+	if (IS_ERR_OR_NULL(utd_entry)) {
+		if (utd_res)
+			*utd_res = utd_entry;
+		return NULL;
+	}
+
+	tr_entry = tag_ref_tree_search(&utd_entry->tag_ref_tree, full_tag);
+	if (utd_res)
+		*utd_res = utd_entry;
+	DR_DEBUG("qtaguid: lookup_tag_ref(0x%llx) utd_entry=%p tr_entry=%p\n",
+		 full_tag, utd_entry, tr_entry);
+	return tr_entry;
+}
+
+/* Never returns NULL. Either PTR_ERR or a valid ptr. */
+static struct tag_ref *get_tag_ref(tag_t full_tag,
+				   struct uid_tag_data **utd_res)
+{
+	struct uid_tag_data *utd_entry;
+	struct tag_ref *tr_entry;
+
+	DR_DEBUG("qtaguid: get_tag_ref(0x%llx)\n",
+		 full_tag);
+	spin_lock_bh(&uid_tag_data_tree_lock);
+	tr_entry = lookup_tag_ref(full_tag, &utd_entry);
+	BUG_ON(IS_ERR_OR_NULL(utd_entry));
+	if (!tr_entry)
+		tr_entry = new_tag_ref(full_tag, utd_entry);
+
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+	if (utd_res)
+		*utd_res = utd_entry;
+	DR_DEBUG("qtaguid: get_tag_ref(0x%llx) utd=%p tr=%p\n",
+		 full_tag, utd_entry, tr_entry);
+	return tr_entry;
+}
+
+/* Checks and maybe frees the UID Tag Data entry */
+static void put_utd_entry(struct uid_tag_data *utd_entry)
+{
+	/* Are we done with the UID tag data entry? */
+	if (RB_EMPTY_ROOT(&utd_entry->tag_ref_tree) &&
+		!utd_entry->num_pqd) {
+		DR_DEBUG("qtaguid: %s(): "
+			 "erase utd_entry=%p uid=%u "
+			 "by pid=%u tgid=%u uid=%u\n", __func__,
+			 utd_entry, utd_entry->uid,
+			 current->pid, current->tgid, current_fsuid());
+		BUG_ON(utd_entry->num_active_tags);
+		rb_erase(&utd_entry->node, &uid_tag_data_tree);
+		kfree(utd_entry);
+	} else {
+		DR_DEBUG("qtaguid: %s(): "
+			 "utd_entry=%p still has %d tags %d proc_qtu_data\n",
+			 __func__, utd_entry, utd_entry->num_active_tags,
+			 utd_entry->num_pqd);
+		BUG_ON(!(utd_entry->num_active_tags ||
+			 utd_entry->num_pqd));
+	}
+}
+
+/*
+ * If no sock_tags are using this tag_ref,
+ * decrements refcount of utd_entry, removes tr_entry
+ * from utd_entry->tag_ref_tree and frees.
+ */
+static void free_tag_ref_from_utd_entry(struct tag_ref *tr_entry,
+					struct uid_tag_data *utd_entry)
+{
+	DR_DEBUG("qtaguid: %s(): %p tag=0x%llx (uid=%u)\n", __func__,
+		 tr_entry, tr_entry->tn.tag,
+		 get_uid_from_tag(tr_entry->tn.tag));
+	if (!tr_entry->num_sock_tags) {
+		BUG_ON(!utd_entry->num_active_tags);
+		utd_entry->num_active_tags--;
+		rb_erase(&tr_entry->tn.node, &utd_entry->tag_ref_tree);
+		DR_DEBUG("qtaguid: %s(): erased %p\n", __func__, tr_entry);
+		kfree(tr_entry);
+	}
+}
+
+static void put_tag_ref_tree(tag_t full_tag, struct uid_tag_data *utd_entry)
+{
+	struct rb_node *node;
+	struct tag_ref *tr_entry;
+	tag_t acct_tag;
+
+	DR_DEBUG("qtaguid: %s(tag=0x%llx (uid=%u))\n", __func__,
+		 full_tag, get_uid_from_tag(full_tag));
+	acct_tag = get_atag_from_tag(full_tag);
+	node = rb_first(&utd_entry->tag_ref_tree);
+	while (node) {
+		tr_entry = rb_entry(node, struct tag_ref, tn.node);
+		node = rb_next(node);
+		if (!acct_tag || tr_entry->tn.tag == full_tag)
+			free_tag_ref_from_utd_entry(tr_entry, utd_entry);
+	}
+}
+
+static int read_proc_u64(char *page, char **start, off_t off,
+			int count, int *eof, void *data)
+{
+	int len;
+	uint64_t value;
+	char *p = page;
+	uint64_t *iface_entry = data;
+
+	if (!data)
+		return 0;
+
+	value = *iface_entry;
+	p += sprintf(p, "%llu\n", value);
+	len = (p - page) - off;
+	*eof = (len <= count) ? 1 : 0;
+	*start = page + off;
+	return len;
+}
+
+static int read_proc_bool(char *page, char **start, off_t off,
+			int count, int *eof, void *data)
+{
+	int len;
+	bool value;
+	char *p = page;
+	bool *bool_entry = data;
+
+	if (!data)
+		return 0;
+
+	value = *bool_entry;
+	p += sprintf(p, "%u\n", value);
+	len = (p - page) - off;
+	*eof = (len <= count) ? 1 : 0;
+	*start = page + off;
+	return len;
+}
+
+static int get_active_counter_set(tag_t tag)
+{
+	int active_set = 0;
+	struct tag_counter_set *tcs;
+
+	MT_DEBUG("qtaguid: get_active_counter_set(tag=0x%llx)"
+		 " (uid=%u)\n",
+		 tag, get_uid_from_tag(tag));
+	/* For now we only handle UID tags for active sets */
+	tag = get_utag_from_tag(tag);
+	spin_lock_bh(&tag_counter_set_list_lock);
+	tcs = tag_counter_set_tree_search(&tag_counter_set_tree, tag);
+	if (tcs)
+		active_set = tcs->active_set;
+	spin_unlock_bh(&tag_counter_set_list_lock);
+	return active_set;
+}
+
+/*
+ * Find the entry for tracking the specified interface.
+ * Caller must hold iface_stat_list_lock
+ */
+static struct iface_stat *get_iface_entry(const char *ifname)
+{
+	struct iface_stat *iface_entry;
+
+	/* Find the entry for tracking the specified tag within the interface */
+	if (ifname == NULL) {
+		pr_info("qtaguid: iface_stat: get() NULL device name\n");
+		return NULL;
+	}
+
+	/* Iterate over interfaces */
+	list_for_each_entry(iface_entry, &iface_stat_list, list) {
+		if (!strcmp(ifname, iface_entry->ifname))
+			goto done;
+	}
+	iface_entry = NULL;
+done:
+	return iface_entry;
+}
+
+static int iface_stat_all_proc_read(char *page, char **num_items_returned,
+				    off_t items_to_skip, int char_count,
+				    int *eof, void *data)
+{
+	char *outp = page;
+	int item_index = 0;
+	int len;
+	struct iface_stat *iface_entry;
+	struct rtnl_link_stats64 dev_stats, *stats;
+	struct rtnl_link_stats64 no_dev_stats = {0};
+
+	if (unlikely(module_passive)) {
+		*eof = 1;
+		return 0;
+	}
+
+	CT_DEBUG("qtaguid:proc iface_stat_all "
+		 "page=%p *num_items_returned=%p off=%ld "
+		 "char_count=%d *eof=%d\n", page, *num_items_returned,
+		 items_to_skip, char_count, *eof);
+
+	if (*eof)
+		return 0;
+
+	/*
+	 * This lock will prevent iface_stat_update() from changing active,
+	 * and in turn prevent an interface from unregistering itself.
+	 */
+	spin_lock_bh(&iface_stat_list_lock);
+	list_for_each_entry(iface_entry, &iface_stat_list, list) {
+		if (item_index++ < items_to_skip)
+			continue;
+
+		if (iface_entry->active) {
+			stats = dev_get_stats(iface_entry->net_dev,
+					      &dev_stats);
+		} else {
+			stats = &no_dev_stats;
+		}
+		len = snprintf(outp, char_count,
+			       "%s %d "
+			       "%llu %llu %llu %llu "
+			       "%llu %llu %llu %llu\n",
+			       iface_entry->ifname,
+			       iface_entry->active,
+			       iface_entry->totals[IFS_RX].bytes,
+			       iface_entry->totals[IFS_RX].packets,
+			       iface_entry->totals[IFS_TX].bytes,
+			       iface_entry->totals[IFS_TX].packets,
+			       stats->rx_bytes, stats->rx_packets,
+			       stats->tx_bytes, stats->tx_packets);
+		if (len >= char_count) {
+			spin_unlock_bh(&iface_stat_list_lock);
+			*outp = '\0';
+			return outp - page;
+		}
+		outp += len;
+		char_count -= len;
+		(*num_items_returned)++;
+	}
+	spin_unlock_bh(&iface_stat_list_lock);
+
+	*eof = 1;
+	return outp - page;
+}
+
+static void iface_create_proc_worker(struct work_struct *work)
+{
+	struct proc_dir_entry *proc_entry;
+	struct iface_stat_work *isw = container_of(work, struct iface_stat_work,
+						   iface_work);
+	struct iface_stat *new_iface  = isw->iface_entry;
+
+	/* iface_entries are not deleted, so safe to manipulate. */
+	proc_entry = proc_mkdir(new_iface->ifname, iface_stat_procdir);
+	if (IS_ERR_OR_NULL(proc_entry)) {
+		pr_err("qtaguid: iface_stat: create_proc(): alloc failed.\n");
+		kfree(isw);
+		return;
+	}
+
+	new_iface->proc_ptr = proc_entry;
+
+	create_proc_read_entry("tx_bytes", proc_iface_perms, proc_entry,
+			read_proc_u64, &new_iface->totals[IFS_TX].bytes);
+	create_proc_read_entry("rx_bytes", proc_iface_perms, proc_entry,
+			read_proc_u64, &new_iface->totals[IFS_RX].bytes);
+	create_proc_read_entry("tx_packets", proc_iface_perms, proc_entry,
+			read_proc_u64, &new_iface->totals[IFS_TX].packets);
+	create_proc_read_entry("rx_packets", proc_iface_perms, proc_entry,
+			read_proc_u64, &new_iface->totals[IFS_RX].packets);
+	create_proc_read_entry("active", proc_iface_perms, proc_entry,
+			read_proc_bool, &new_iface->active);
+
+	IF_DEBUG("qtaguid: iface_stat: create_proc(): done "
+		 "entry=%p dev=%s\n", new_iface, new_iface->ifname);
+	kfree(isw);
+}
+
+/*
+ * Will set the entry's active state, and
+ * update the net_dev accordingly also.
+ */
+static void _iface_stat_set_active(struct iface_stat *entry,
+				   struct net_device *net_dev,
+				   bool activate)
+{
+	if (activate) {
+		entry->net_dev = net_dev;
+		entry->active = true;
+		IF_DEBUG("qtaguid: %s(%s): "
+			 "enable tracking. rfcnt=%d\n", __func__,
+			 entry->ifname,
+			 this_cpu_read(*net_dev->pcpu_refcnt));
+	} else {
+		entry->active = false;
+		entry->net_dev = NULL;
+		IF_DEBUG("qtaguid: %s(%s): "
+			 "disable tracking. rfcnt=%d\n", __func__,
+			 entry->ifname,
+			 this_cpu_read(*net_dev->pcpu_refcnt));
+
+	}
+}
+
+/* Caller must hold iface_stat_list_lock */
+static struct iface_stat *iface_alloc(struct net_device *net_dev)
+{
+	struct iface_stat *new_iface;
+	struct iface_stat_work *isw;
+
+	new_iface = kzalloc(sizeof(*new_iface), GFP_ATOMIC);
+	if (new_iface == NULL) {
+		pr_err("qtaguid: iface_stat: create(%s): "
+		       "iface_stat alloc failed\n", net_dev->name);
+		return NULL;
+	}
+	new_iface->ifname = kstrdup(net_dev->name, GFP_ATOMIC);
+	if (new_iface->ifname == NULL) {
+		pr_err("qtaguid: iface_stat: create(%s): "
+		       "ifname alloc failed\n", net_dev->name);
+		kfree(new_iface);
+		return NULL;
+	}
+	spin_lock_init(&new_iface->tag_stat_list_lock);
+	new_iface->tag_stat_tree = RB_ROOT;
+	_iface_stat_set_active(new_iface, net_dev, true);
+
+	/*
+	 * ipv6 notifier chains are atomic :(
+	 * No create_proc_read_entry() for you!
+	 */
+	isw = kmalloc(sizeof(*isw), GFP_ATOMIC);
+	if (!isw) {
+		pr_err("qtaguid: iface_stat: create(%s): "
+		       "work alloc failed\n", new_iface->ifname);
+		_iface_stat_set_active(new_iface, net_dev, false);
+		kfree(new_iface->ifname);
+		kfree(new_iface);
+		return NULL;
+	}
+	isw->iface_entry = new_iface;
+	INIT_WORK(&isw->iface_work, iface_create_proc_worker);
+	schedule_work(&isw->iface_work);
+	list_add(&new_iface->list, &iface_stat_list);
+	return new_iface;
+}
+
+static void iface_check_stats_reset_and_adjust(struct net_device *net_dev,
+					       struct iface_stat *iface)
+{
+	struct rtnl_link_stats64 dev_stats, *stats;
+	bool stats_rewound;
+
+	stats = dev_get_stats(net_dev, &dev_stats);
+	/* No empty packets */
+	stats_rewound =
+		(stats->rx_bytes < iface->last_known[IFS_RX].bytes)
+		|| (stats->tx_bytes < iface->last_known[IFS_TX].bytes);
+
+	IF_DEBUG("qtaguid: %s(%s): iface=%p netdev=%p "
+		 "bytes rx/tx=%llu/%llu "
+		 "active=%d last_known=%d "
+		 "stats_rewound=%d\n", __func__,
+		 net_dev ? net_dev->name : "?",
+		 iface, net_dev,
+		 stats->rx_bytes, stats->tx_bytes,
+		 iface->active, iface->last_known_valid, stats_rewound);
+
+	if (iface->active && iface->last_known_valid && stats_rewound) {
+		pr_warn_once("qtaguid: iface_stat: %s(%s): "
+			     "iface reset its stats unexpectedly\n", __func__,
+			     net_dev->name);
+
+		iface->totals[IFS_TX].bytes += iface->last_known[IFS_TX].bytes;
+		iface->totals[IFS_TX].packets +=
+			iface->last_known[IFS_TX].packets;
+		iface->totals[IFS_RX].bytes += iface->last_known[IFS_RX].bytes;
+		iface->totals[IFS_RX].packets +=
+			iface->last_known[IFS_RX].packets;
+		iface->last_known_valid = false;
+		IF_DEBUG("qtaguid: %s(%s): iface=%p "
+			 "used last known bytes rx/tx=%llu/%llu\n", __func__,
+			 iface->ifname, iface, iface->last_known[IFS_RX].bytes,
+			 iface->last_known[IFS_TX].bytes);
+	}
+}
+
+/*
+ * Create a new entry for tracking the specified interface.
+ * Do nothing if the entry already exists.
+ * Called when an interface is configured with a valid IP address.
+ */
+static void iface_stat_create(struct net_device *net_dev,
+			      struct in_ifaddr *ifa)
+{
+	struct in_device *in_dev = NULL;
+	const char *ifname;
+	struct iface_stat *entry;
+	__be32 ipaddr = 0;
+	struct iface_stat *new_iface;
+
+	IF_DEBUG("qtaguid: iface_stat: create(%s): ifa=%p netdev=%p\n",
+		 net_dev ? net_dev->name : "?",
+		 ifa, net_dev);
+	if (!net_dev) {
+		pr_err("qtaguid: iface_stat: create(): no net dev\n");
+		return;
+	}
+
+	ifname = net_dev->name;
+	if (!ifa) {
+		in_dev = in_dev_get(net_dev);
+		if (!in_dev) {
+			pr_err("qtaguid: iface_stat: create(%s): no inet dev\n",
+			       ifname);
+			return;
+		}
+		IF_DEBUG("qtaguid: iface_stat: create(%s): in_dev=%p\n",
+			 ifname, in_dev);
+		for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
+			IF_DEBUG("qtaguid: iface_stat: create(%s): "
+				 "ifa=%p ifa_label=%s\n",
+				 ifname, ifa,
+				 ifa->ifa_label ? ifa->ifa_label : "(null)");
+			if (ifa->ifa_label && !strcmp(ifname, ifa->ifa_label))
+				break;
+		}
+	}
+
+	if (!ifa) {
+		IF_DEBUG("qtaguid: iface_stat: create(%s): no matching IP\n",
+			 ifname);
+		goto done_put;
+	}
+	ipaddr = ifa->ifa_local;
+
+	spin_lock_bh(&iface_stat_list_lock);
+	entry = get_iface_entry(ifname);
+	if (entry != NULL) {
+		bool activate = !ipv4_is_loopback(ipaddr);
+		IF_DEBUG("qtaguid: iface_stat: create(%s): entry=%p\n",
+			 ifname, entry);
+		iface_check_stats_reset_and_adjust(net_dev, entry);
+		_iface_stat_set_active(entry, net_dev, activate);
+		IF_DEBUG("qtaguid: %s(%s): "
+			 "tracking now %d on ip=%pI4\n", __func__,
+			 entry->ifname, activate, &ipaddr);
+		goto done_unlock_put;
+	} else if (ipv4_is_loopback(ipaddr)) {
+		IF_DEBUG("qtaguid: iface_stat: create(%s): "
+			 "ignore loopback dev. ip=%pI4\n", ifname, &ipaddr);
+		goto done_unlock_put;
+	}
+
+	new_iface = iface_alloc(net_dev);
+	IF_DEBUG("qtaguid: iface_stat: create(%s): done "
+		 "entry=%p ip=%pI4\n", ifname, new_iface, &ipaddr);
+done_unlock_put:
+	spin_unlock_bh(&iface_stat_list_lock);
+done_put:
+	if (in_dev)
+		in_dev_put(in_dev);
+}
+
+static void iface_stat_create_ipv6(struct net_device *net_dev,
+				   struct inet6_ifaddr *ifa)
+{
+	struct in_device *in_dev;
+	const char *ifname;
+	struct iface_stat *entry;
+	struct iface_stat *new_iface;
+	int addr_type;
+
+	IF_DEBUG("qtaguid: iface_stat: create6(): ifa=%p netdev=%p->name=%s\n",
+		 ifa, net_dev, net_dev ? net_dev->name : "");
+	if (!net_dev) {
+		pr_err("qtaguid: iface_stat: create6(): no net dev!\n");
+		return;
+	}
+	ifname = net_dev->name;
+
+	in_dev = in_dev_get(net_dev);
+	if (!in_dev) {
+		pr_err("qtaguid: iface_stat: create6(%s): no inet dev\n",
+		       ifname);
+		return;
+	}
+
+	IF_DEBUG("qtaguid: iface_stat: create6(%s): in_dev=%p\n",
+		 ifname, in_dev);
+
+	if (!ifa) {
+		IF_DEBUG("qtaguid: iface_stat: create6(%s): no matching IP\n",
+			 ifname);
+		goto done_put;
+	}
+	addr_type = ipv6_addr_type(&ifa->addr);
+
+	spin_lock_bh(&iface_stat_list_lock);
+	entry = get_iface_entry(ifname);
+	if (entry != NULL) {
+		bool activate = !(addr_type & IPV6_ADDR_LOOPBACK);
+		IF_DEBUG("qtaguid: %s(%s): entry=%p\n", __func__,
+			 ifname, entry);
+		iface_check_stats_reset_and_adjust(net_dev, entry);
+		_iface_stat_set_active(entry, net_dev, activate);
+		IF_DEBUG("qtaguid: %s(%s): "
+			 "tracking now %d on ip=%pI6c\n", __func__,
+			 entry->ifname, activate, &ifa->addr);
+		goto done_unlock_put;
+	} else if (addr_type & IPV6_ADDR_LOOPBACK) {
+		IF_DEBUG("qtaguid: %s(%s): "
+			 "ignore loopback dev. ip=%pI6c\n", __func__,
+			 ifname, &ifa->addr);
+		goto done_unlock_put;
+	}
+
+	new_iface = iface_alloc(net_dev);
+	IF_DEBUG("qtaguid: iface_stat: create6(%s): done "
+		 "entry=%p ip=%pI6c\n", ifname, new_iface, &ifa->addr);
+
+done_unlock_put:
+	spin_unlock_bh(&iface_stat_list_lock);
+done_put:
+	in_dev_put(in_dev);
+}
+
+static struct sock_tag *get_sock_stat_nl(const struct sock *sk)
+{
+	MT_DEBUG("qtaguid: get_sock_stat_nl(sk=%p)\n", sk);
+	return sock_tag_tree_search(&sock_tag_tree, sk);
+}
+
+static struct sock_tag *get_sock_stat(const struct sock *sk)
+{
+	struct sock_tag *sock_tag_entry;
+	MT_DEBUG("qtaguid: get_sock_stat(sk=%p)\n", sk);
+	if (!sk)
+		return NULL;
+	spin_lock_bh(&sock_tag_list_lock);
+	sock_tag_entry = get_sock_stat_nl(sk);
+	spin_unlock_bh(&sock_tag_list_lock);
+	return sock_tag_entry;
+}
+
+static void
+data_counters_update(struct data_counters *dc, int set,
+		     enum ifs_tx_rx direction, int proto, int bytes)
+{
+	switch (proto) {
+	case IPPROTO_TCP:
+		dc_add_byte_packets(dc, set, direction, IFS_TCP, bytes, 1);
+		break;
+	case IPPROTO_UDP:
+		dc_add_byte_packets(dc, set, direction, IFS_UDP, bytes, 1);
+		break;
+	case IPPROTO_IP:
+	default:
+		dc_add_byte_packets(dc, set, direction, IFS_PROTO_OTHER, bytes,
+				    1);
+		break;
+	}
+}
+
+/*
+ * Update stats for the specified interface. Do nothing if the entry
+ * does not exist (when a device was never configured with an IP address).
+ * Called when an device is being unregistered.
+ */
+static void iface_stat_update(struct net_device *net_dev, bool stash_only)
+{
+	struct rtnl_link_stats64 dev_stats, *stats;
+	struct iface_stat *entry;
+
+	stats = dev_get_stats(net_dev, &dev_stats);
+	spin_lock_bh(&iface_stat_list_lock);
+	entry = get_iface_entry(net_dev->name);
+	if (entry == NULL) {
+		IF_DEBUG("qtaguid: iface_stat: update(%s): not tracked\n",
+			 net_dev->name);
+		spin_unlock_bh(&iface_stat_list_lock);
+		return;
+	}
+
+	IF_DEBUG("qtaguid: %s(%s): entry=%p\n", __func__,
+		 net_dev->name, entry);
+	if (!entry->active) {
+		IF_DEBUG("qtaguid: %s(%s): already disabled\n", __func__,
+			 net_dev->name);
+		spin_unlock_bh(&iface_stat_list_lock);
+		return;
+	}
+
+	if (stash_only) {
+		entry->last_known[IFS_TX].bytes = stats->tx_bytes;
+		entry->last_known[IFS_TX].packets = stats->tx_packets;
+		entry->last_known[IFS_RX].bytes = stats->rx_bytes;
+		entry->last_known[IFS_RX].packets = stats->rx_packets;
+		entry->last_known_valid = true;
+		IF_DEBUG("qtaguid: %s(%s): "
+			 "dev stats stashed rx/tx=%llu/%llu\n", __func__,
+			 net_dev->name, stats->rx_bytes, stats->tx_bytes);
+		spin_unlock_bh(&iface_stat_list_lock);
+		return;
+	}
+	entry->totals[IFS_TX].bytes += stats->tx_bytes;
+	entry->totals[IFS_TX].packets += stats->tx_packets;
+	entry->totals[IFS_RX].bytes += stats->rx_bytes;
+	entry->totals[IFS_RX].packets += stats->rx_packets;
+	/* We don't need the last_known[] anymore */
+	entry->last_known_valid = false;
+	_iface_stat_set_active(entry, net_dev, false);
+	IF_DEBUG("qtaguid: %s(%s): "
+		 "disable tracking. rx/tx=%llu/%llu\n", __func__,
+		 net_dev->name, stats->rx_bytes, stats->tx_bytes);
+	spin_unlock_bh(&iface_stat_list_lock);
+}
+
+static void tag_stat_update(struct tag_stat *tag_entry,
+			enum ifs_tx_rx direction, int proto, int bytes)
+{
+	int active_set;
+	active_set = get_active_counter_set(tag_entry->tn.tag);
+	MT_DEBUG("qtaguid: tag_stat_update(tag=0x%llx (uid=%u) set=%d "
+		 "dir=%d proto=%d bytes=%d)\n",
+		 tag_entry->tn.tag, get_uid_from_tag(tag_entry->tn.tag),
+		 active_set, direction, proto, bytes);
+	data_counters_update(&tag_entry->counters, active_set, direction,
+			     proto, bytes);
+	if (tag_entry->parent_counters)
+		data_counters_update(tag_entry->parent_counters, active_set,
+				     direction, proto, bytes);
+}
+
+/*
+ * Create a new entry for tracking the specified {acct_tag,uid_tag} within
+ * the interface.
+ * iface_entry->tag_stat_list_lock should be held.
+ */
+static struct tag_stat *create_if_tag_stat(struct iface_stat *iface_entry,
+					   tag_t tag)
+{
+	struct tag_stat *new_tag_stat_entry = NULL;
+	IF_DEBUG("qtaguid: iface_stat: %s(): ife=%p tag=0x%llx"
+		 " (uid=%u)\n", __func__,
+		 iface_entry, tag, get_uid_from_tag(tag));
+	new_tag_stat_entry = kzalloc(sizeof(*new_tag_stat_entry), GFP_ATOMIC);
+	if (!new_tag_stat_entry) {
+		pr_err("qtaguid: iface_stat: tag stat alloc failed\n");
+		goto done;
+	}
+	new_tag_stat_entry->tn.tag = tag;
+	tag_stat_tree_insert(new_tag_stat_entry, &iface_entry->tag_stat_tree);
+done:
+	return new_tag_stat_entry;
+}
+
+static void if_tag_stat_update(const char *ifname, uid_t uid,
+			       const struct sock *sk, enum ifs_tx_rx direction,
+			       int proto, int bytes)
+{
+	struct tag_stat *tag_stat_entry;
+	tag_t tag, acct_tag;
+	tag_t uid_tag;
+	struct data_counters *uid_tag_counters;
+	struct sock_tag *sock_tag_entry;
+	struct iface_stat *iface_entry;
+	struct tag_stat *new_tag_stat;
+	MT_DEBUG("qtaguid: if_tag_stat_update(ifname=%s "
+		"uid=%u sk=%p dir=%d proto=%d bytes=%d)\n",
+		 ifname, uid, sk, direction, proto, bytes);
+
+
+	iface_entry = get_iface_entry(ifname);
+	if (!iface_entry) {
+		pr_err("qtaguid: iface_stat: stat_update() %s not found\n",
+		       ifname);
+		return;
+	}
+	/* It is ok to process data when an iface_entry is inactive */
+
+	MT_DEBUG("qtaguid: iface_stat: stat_update() dev=%s entry=%p\n",
+		 ifname, iface_entry);
+
+	/*
+	 * Look for a tagged sock.
+	 * It will have an acct_uid.
+	 */
+	sock_tag_entry = get_sock_stat(sk);
+	if (sock_tag_entry) {
+		tag = sock_tag_entry->tag;
+		acct_tag = get_atag_from_tag(tag);
+		uid_tag = get_utag_from_tag(tag);
+	} else {
+		acct_tag = make_atag_from_value(0);
+		tag = combine_atag_with_uid(acct_tag, uid);
+		uid_tag = make_tag_from_uid(uid);
+	}
+	MT_DEBUG("qtaguid: iface_stat: stat_update(): "
+		 " looking for tag=0x%llx (uid=%u) in ife=%p\n",
+		 tag, get_uid_from_tag(tag), iface_entry);
+	/* Loop over tag list under this interface for {acct_tag,uid_tag} */
+	spin_lock_bh(&iface_entry->tag_stat_list_lock);
+
+	tag_stat_entry = tag_stat_tree_search(&iface_entry->tag_stat_tree,
+					      tag);
+	if (tag_stat_entry) {
+		/*
+		 * Updating the {acct_tag, uid_tag} entry handles both stats:
+		 * {0, uid_tag} will also get updated.
+		 */
+		tag_stat_update(tag_stat_entry, direction, proto, bytes);
+		spin_unlock_bh(&iface_entry->tag_stat_list_lock);
+		return;
+	}
+
+	/* Loop over tag list under this interface for {0,uid_tag} */
+	tag_stat_entry = tag_stat_tree_search(&iface_entry->tag_stat_tree,
+					      uid_tag);
+	if (!tag_stat_entry) {
+		/* Here: the base uid_tag did not exist */
+		/*
+		 * No parent counters. So
+		 *  - No {0, uid_tag} stats and no {acc_tag, uid_tag} stats.
+		 */
+		new_tag_stat = create_if_tag_stat(iface_entry, uid_tag);
+		uid_tag_counters = &new_tag_stat->counters;
+	} else {
+		uid_tag_counters = &tag_stat_entry->counters;
+	}
+
+	if (acct_tag) {
+		new_tag_stat = create_if_tag_stat(iface_entry, tag);
+		new_tag_stat->parent_counters = uid_tag_counters;
+	}
+	tag_stat_update(new_tag_stat, direction, proto, bytes);
+	spin_unlock_bh(&iface_entry->tag_stat_list_lock);
+}
+
+static int iface_netdev_event_handler(struct notifier_block *nb,
+				      unsigned long event, void *ptr) {
+	struct net_device *dev = ptr;
+
+	if (unlikely(module_passive))
+		return NOTIFY_DONE;
+
+	IF_DEBUG("qtaguid: iface_stat: netdev_event(): "
+		 "ev=0x%lx/%s netdev=%p->name=%s\n",
+		 event, netdev_evt_str(event), dev, dev ? dev->name : "");
+
+	switch (event) {
+	case NETDEV_UP:
+		iface_stat_create(dev, NULL);
+		atomic64_inc(&qtu_events.iface_events);
+		break;
+	case NETDEV_DOWN:
+	case NETDEV_UNREGISTER:
+		iface_stat_update(dev, event == NETDEV_DOWN);
+		atomic64_inc(&qtu_events.iface_events);
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static int iface_inet6addr_event_handler(struct notifier_block *nb,
+					 unsigned long event, void *ptr)
+{
+	struct inet6_ifaddr *ifa = ptr;
+	struct net_device *dev;
+
+	if (unlikely(module_passive))
+		return NOTIFY_DONE;
+
+	IF_DEBUG("qtaguid: iface_stat: inet6addr_event(): "
+		 "ev=0x%lx/%s ifa=%p\n",
+		 event, netdev_evt_str(event), ifa);
+
+	switch (event) {
+	case NETDEV_UP:
+		BUG_ON(!ifa || !ifa->idev);
+		dev = (struct net_device *)ifa->idev->dev;
+		iface_stat_create_ipv6(dev, ifa);
+		atomic64_inc(&qtu_events.iface_events);
+		break;
+	case NETDEV_DOWN:
+	case NETDEV_UNREGISTER:
+		BUG_ON(!ifa || !ifa->idev);
+		dev = (struct net_device *)ifa->idev->dev;
+		iface_stat_update(dev, event == NETDEV_DOWN);
+		atomic64_inc(&qtu_events.iface_events);
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static int iface_inetaddr_event_handler(struct notifier_block *nb,
+					unsigned long event, void *ptr)
+{
+	struct in_ifaddr *ifa = ptr;
+	struct net_device *dev;
+
+	if (unlikely(module_passive))
+		return NOTIFY_DONE;
+
+	IF_DEBUG("qtaguid: iface_stat: inetaddr_event(): "
+		 "ev=0x%lx/%s ifa=%p\n",
+		 event, netdev_evt_str(event), ifa);
+
+	switch (event) {
+	case NETDEV_UP:
+		BUG_ON(!ifa || !ifa->ifa_dev);
+		dev = ifa->ifa_dev->dev;
+		iface_stat_create(dev, ifa);
+		atomic64_inc(&qtu_events.iface_events);
+		break;
+	case NETDEV_DOWN:
+	case NETDEV_UNREGISTER:
+		BUG_ON(!ifa || !ifa->ifa_dev);
+		dev = ifa->ifa_dev->dev;
+		iface_stat_update(dev, event == NETDEV_DOWN);
+		atomic64_inc(&qtu_events.iface_events);
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block iface_netdev_notifier_blk = {
+	.notifier_call = iface_netdev_event_handler,
+};
+
+static struct notifier_block iface_inetaddr_notifier_blk = {
+	.notifier_call = iface_inetaddr_event_handler,
+};
+
+static struct notifier_block iface_inet6addr_notifier_blk = {
+	.notifier_call = iface_inet6addr_event_handler,
+};
+
+static int __init iface_stat_init(struct proc_dir_entry *parent_procdir)
+{
+	int err;
+
+	iface_stat_procdir = proc_mkdir(iface_stat_procdirname, parent_procdir);
+	if (!iface_stat_procdir) {
+		pr_err("qtaguid: iface_stat: init failed to create proc entry\n");
+		err = -1;
+		goto err;
+	}
+
+	iface_stat_all_procfile = create_proc_entry(iface_stat_all_procfilename,
+						    proc_iface_perms,
+						    parent_procdir);
+	if (!iface_stat_all_procfile) {
+		pr_err("qtaguid: iface_stat: init "
+		       " failed to create stat_all proc entry\n");
+		err = -1;
+		goto err_zap_entry;
+	}
+	iface_stat_all_procfile->read_proc = iface_stat_all_proc_read;
+
+
+	err = register_netdevice_notifier(&iface_netdev_notifier_blk);
+	if (err) {
+		pr_err("qtaguid: iface_stat: init "
+		       "failed to register dev event handler\n");
+		goto err_zap_all_stats_entry;
+	}
+	err = register_inetaddr_notifier(&iface_inetaddr_notifier_blk);
+	if (err) {
+		pr_err("qtaguid: iface_stat: init "
+		       "failed to register ipv4 dev event handler\n");
+		goto err_unreg_nd;
+	}
+
+	err = register_inet6addr_notifier(&iface_inet6addr_notifier_blk);
+	if (err) {
+		pr_err("qtaguid: iface_stat: init "
+		       "failed to register ipv6 dev event handler\n");
+		goto err_unreg_ip4_addr;
+	}
+	return 0;
+
+err_unreg_ip4_addr:
+	unregister_inetaddr_notifier(&iface_inetaddr_notifier_blk);
+err_unreg_nd:
+	unregister_netdevice_notifier(&iface_netdev_notifier_blk);
+err_zap_all_stats_entry:
+	remove_proc_entry(iface_stat_all_procfilename, parent_procdir);
+err_zap_entry:
+	remove_proc_entry(iface_stat_procdirname, parent_procdir);
+err:
+	return err;
+}
+
+static struct sock *qtaguid_find_sk(const struct sk_buff *skb,
+				    struct xt_action_param *par)
+{
+	struct sock *sk;
+	unsigned int hook_mask = (1 << par->hooknum);
+
+	MT_DEBUG("qtaguid: find_sk(skb=%p) hooknum=%d family=%d\n", skb,
+		 par->hooknum, par->family);
+
+	/*
+	 * Let's not abuse the the xt_socket_get*_sk(), or else it will
+	 * return garbage SKs.
+	 */
+	if (!(hook_mask & XT_SOCKET_SUPPORTED_HOOKS))
+		return NULL;
+
+	switch (par->family) {
+	case NFPROTO_IPV6:
+		sk = xt_socket_get6_sk(skb, par);
+		break;
+	case NFPROTO_IPV4:
+		sk = xt_socket_get4_sk(skb, par);
+		break;
+	default:
+		return NULL;
+	}
+
+	/*
+	 * Seems to be issues on the file ptr for TCP_TIME_WAIT SKs.
+	 * http://kerneltrap.org/mailarchive/linux-netdev/2010/10/21/6287959
+	 * Not fixed in 3.0-r3 :(
+	 */
+	if (sk) {
+		MT_DEBUG("qtaguid: %p->sk_proto=%u "
+			 "->sk_state=%d\n", sk, sk->sk_protocol, sk->sk_state);
+		if (sk->sk_state  == TCP_TIME_WAIT) {
+			xt_socket_put_sk(sk);
+			sk = NULL;
+		}
+	}
+	return sk;
+}
+
+static void account_for_uid(const struct sk_buff *skb,
+			    const struct sock *alternate_sk, uid_t uid,
+			    struct xt_action_param *par)
+{
+	const struct net_device *el_dev;
+
+	if (!skb->dev) {
+		MT_DEBUG("qtaguid[%d]: no skb->dev\n", par->hooknum);
+		el_dev = par->in ? : par->out;
+	} else {
+		const struct net_device *other_dev;
+		el_dev = skb->dev;
+		other_dev = par->in ? : par->out;
+		if (el_dev != other_dev) {
+			MT_DEBUG("qtaguid[%d]: skb->dev=%p %s vs "
+				"par->(in/out)=%p %s\n",
+				par->hooknum, el_dev, el_dev->name, other_dev,
+				other_dev->name);
+		}
+	}
+
+	if (unlikely(!el_dev)) {
+		pr_info("qtaguid[%d]: no par->in/out?!!\n", par->hooknum);
+	} else if (unlikely(!el_dev->name)) {
+		pr_info("qtaguid[%d]: no dev->name?!!\n", par->hooknum);
+	} else {
+		MT_DEBUG("qtaguid[%d]: dev name=%s type=%d\n",
+			 par->hooknum,
+			 el_dev->name,
+			 el_dev->type);
+
+		if_tag_stat_update(el_dev->name, uid,
+				skb->sk ? skb->sk : alternate_sk,
+				par->in ? IFS_RX : IFS_TX,
+				ip_hdr(skb)->protocol, skb->len);
+	}
+}
+
+static bool qtaguid_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+	const struct xt_qtaguid_match_info *info = par->matchinfo;
+	const struct file *filp;
+	bool got_sock = false;
+	struct sock *sk;
+	uid_t sock_uid;
+	bool res;
+
+	if (unlikely(module_passive))
+		return (info->match ^ info->invert) == 0;
+
+	MT_DEBUG("qtaguid[%d]: entered skb=%p par->in=%p/out=%p fam=%d\n",
+		 par->hooknum, skb, par->in, par->out, par->family);
+
+	atomic64_inc(&qtu_events.match_calls);
+	if (skb == NULL) {
+		res = (info->match ^ info->invert) == 0;
+		goto ret_res;
+	}
+
+	sk = skb->sk;
+
+	if (sk == NULL) {
+		/*
+		 * A missing sk->sk_socket happens when packets are in-flight
+		 * and the matching socket is already closed and gone.
+		 */
+		sk = qtaguid_find_sk(skb, par);
+		/*
+		 * If we got the socket from the find_sk(), we will need to put
+		 * it back, as nf_tproxy_get_sock_v4() got it.
+		 */
+		got_sock = sk;
+		if (sk)
+			atomic64_inc(&qtu_events.match_found_sk_in_ct);
+		else
+			atomic64_inc(&qtu_events.match_found_no_sk_in_ct);
+	} else {
+		atomic64_inc(&qtu_events.match_found_sk);
+	}
+	MT_DEBUG("qtaguid[%d]: sk=%p got_sock=%d proto=%d\n",
+		par->hooknum, sk, got_sock, ip_hdr(skb)->protocol);
+	if (sk != NULL) {
+		MT_DEBUG("qtaguid[%d]: sk=%p->sk_socket=%p->file=%p\n",
+			par->hooknum, sk, sk->sk_socket,
+			sk->sk_socket ? sk->sk_socket->file : (void *)-1LL);
+		filp = sk->sk_socket ? sk->sk_socket->file : NULL;
+		MT_DEBUG("qtaguid[%d]: filp...uid=%u\n",
+			par->hooknum, filp ? filp->f_cred->fsuid : -1);
+	}
+
+	if (sk == NULL || sk->sk_socket == NULL) {
+		/*
+		 * Here, the qtaguid_find_sk() using connection tracking
+		 * couldn't find the owner, so for now we just count them
+		 * against the system.
+		 */
+		/*
+		 * TODO: unhack how to force just accounting.
+		 * For now we only do iface stats when the uid-owner is not
+		 * requested.
+		 */
+		if (!(info->match & XT_QTAGUID_UID))
+			account_for_uid(skb, sk, 0, par);
+		MT_DEBUG("qtaguid[%d]: leaving (sk?sk->sk_socket)=%p\n",
+			par->hooknum,
+			sk ? sk->sk_socket : NULL);
+		res = (info->match ^ info->invert) == 0;
+		atomic64_inc(&qtu_events.match_no_sk);
+		goto put_sock_ret_res;
+	} else if (info->match & info->invert & XT_QTAGUID_SOCKET) {
+		res = false;
+		goto put_sock_ret_res;
+	}
+	filp = sk->sk_socket->file;
+	if (filp == NULL) {
+		MT_DEBUG("qtaguid[%d]: leaving filp=NULL\n", par->hooknum);
+		account_for_uid(skb, sk, 0, par);
+		res = ((info->match ^ info->invert) &
+			(XT_QTAGUID_UID | XT_QTAGUID_GID)) == 0;
+		atomic64_inc(&qtu_events.match_no_sk_file);
+		goto put_sock_ret_res;
+	}
+	sock_uid = filp->f_cred->fsuid;
+	/*
+	 * TODO: unhack how to force just accounting.
+	 * For now we only do iface stats when the uid-owner is not requested
+	 */
+	if (!(info->match & XT_QTAGUID_UID))
+		account_for_uid(skb, sk, sock_uid, par);
+
+	/*
+	 * The following two tests fail the match when:
+	 *    id not in range AND no inverted condition requested
+	 * or id     in range AND    inverted condition requested
+	 * Thus (!a && b) || (a && !b) == a ^ b
+	 */
+	if (info->match & XT_QTAGUID_UID)
+		if ((filp->f_cred->fsuid >= info->uid_min &&
+		     filp->f_cred->fsuid <= info->uid_max) ^
+		    !(info->invert & XT_QTAGUID_UID)) {
+			MT_DEBUG("qtaguid[%d]: leaving uid not matching\n",
+				 par->hooknum);
+			res = false;
+			goto put_sock_ret_res;
+		}
+	if (info->match & XT_QTAGUID_GID)
+		if ((filp->f_cred->fsgid >= info->gid_min &&
+				filp->f_cred->fsgid <= info->gid_max) ^
+			!(info->invert & XT_QTAGUID_GID)) {
+			MT_DEBUG("qtaguid[%d]: leaving gid not matching\n",
+				par->hooknum);
+			res = false;
+			goto put_sock_ret_res;
+		}
+
+	MT_DEBUG("qtaguid[%d]: leaving matched\n", par->hooknum);
+	res = true;
+
+put_sock_ret_res:
+	if (got_sock)
+		xt_socket_put_sk(sk);
+ret_res:
+	MT_DEBUG("qtaguid[%d]: left %d\n", par->hooknum, res);
+	return res;
+}
+
+#ifdef DDEBUG
+/* This function is not in xt_qtaguid_print.c because of locks visibility */
+static void prdebug_full_state(int indent_level, const char *fmt, ...)
+{
+	va_list args;
+	char *fmt_buff;
+	char *buff;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	fmt_buff = kasprintf(GFP_ATOMIC,
+			     "qtaguid: %s(): %s {\n", __func__, fmt);
+	BUG_ON(!fmt_buff);
+	va_start(args, fmt);
+	buff = kvasprintf(GFP_ATOMIC,
+			  fmt_buff, args);
+	BUG_ON(!buff);
+	pr_debug("%s", buff);
+	kfree(fmt_buff);
+	kfree(buff);
+	va_end(args);
+
+	spin_lock_bh(&sock_tag_list_lock);
+	prdebug_sock_tag_tree(indent_level, &sock_tag_tree);
+	spin_unlock_bh(&sock_tag_list_lock);
+
+	spin_lock_bh(&sock_tag_list_lock);
+	spin_lock_bh(&uid_tag_data_tree_lock);
+	prdebug_uid_tag_data_tree(indent_level, &uid_tag_data_tree);
+	prdebug_proc_qtu_data_tree(indent_level, &proc_qtu_data_tree);
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+	spin_unlock_bh(&sock_tag_list_lock);
+
+	spin_lock_bh(&iface_stat_list_lock);
+	prdebug_iface_stat_list(indent_level, &iface_stat_list);
+	spin_unlock_bh(&iface_stat_list_lock);
+
+	pr_debug("qtaguid: %s(): }\n", __func__);
+}
+#else
+static void prdebug_full_state(int indent_level, const char *fmt, ...) {}
+#endif
+
+/*
+ * Procfs reader to get all active socket tags using style "1)" as described in
+ * fs/proc/generic.c
+ */
+static int qtaguid_ctrl_proc_read(char *page, char **num_items_returned,
+				  off_t items_to_skip, int char_count, int *eof,
+				  void *data)
+{
+	char *outp = page;
+	int len;
+	uid_t uid;
+	struct rb_node *node;
+	struct sock_tag *sock_tag_entry;
+	int item_index = 0;
+	int indent_level = 0;
+	long f_count;
+
+	if (unlikely(module_passive)) {
+		*eof = 1;
+		return 0;
+	}
+
+	if (*eof)
+		return 0;
+
+	CT_DEBUG("qtaguid: proc ctrl page=%p off=%ld char_count=%d *eof=%d\n",
+		page, items_to_skip, char_count, *eof);
+
+	spin_lock_bh(&sock_tag_list_lock);
+	for (node = rb_first(&sock_tag_tree);
+	     node;
+	     node = rb_next(node)) {
+		if (item_index++ < items_to_skip)
+			continue;
+		sock_tag_entry = rb_entry(node, struct sock_tag, sock_node);
+		uid = get_uid_from_tag(sock_tag_entry->tag);
+		CT_DEBUG("qtaguid: proc_read(): sk=%p tag=0x%llx (uid=%u) "
+			 "pid=%u\n",
+			 sock_tag_entry->sk,
+			 sock_tag_entry->tag,
+			 uid,
+			 sock_tag_entry->pid
+			);
+		f_count = atomic_long_read(
+			&sock_tag_entry->socket->file->f_count);
+		len = snprintf(outp, char_count,
+			       "sock=%p tag=0x%llx (uid=%u) pid=%u "
+			       "f_count=%lu\n",
+			       sock_tag_entry->sk,
+			       sock_tag_entry->tag, uid,
+			       sock_tag_entry->pid, f_count);
+		if (len >= char_count) {
+			spin_unlock_bh(&sock_tag_list_lock);
+			*outp = '\0';
+			return outp - page;
+		}
+		outp += len;
+		char_count -= len;
+		(*num_items_returned)++;
+	}
+	spin_unlock_bh(&sock_tag_list_lock);
+
+	if (item_index++ >= items_to_skip) {
+		len = snprintf(outp, char_count,
+			       "events: sockets_tagged=%llu "
+			       "sockets_untagged=%llu "
+			       "counter_set_changes=%llu "
+			       "delete_cmds=%llu "
+			       "iface_events=%llu "
+			       "match_calls=%llu "
+			       "match_found_sk=%llu "
+			       "match_found_sk_in_ct=%llu "
+			       "match_found_no_sk_in_ct=%llu "
+			       "match_no_sk=%llu "
+			       "match_no_sk_file=%llu\n",
+			       atomic64_read(&qtu_events.sockets_tagged),
+			       atomic64_read(&qtu_events.sockets_untagged),
+			       atomic64_read(&qtu_events.counter_set_changes),
+			       atomic64_read(&qtu_events.delete_cmds),
+			       atomic64_read(&qtu_events.iface_events),
+			       atomic64_read(&qtu_events.match_calls),
+			       atomic64_read(&qtu_events.match_found_sk),
+			       atomic64_read(&qtu_events.match_found_sk_in_ct),
+			       atomic64_read(
+				       &qtu_events.match_found_no_sk_in_ct),
+			       atomic64_read(&qtu_events.match_no_sk),
+			       atomic64_read(&qtu_events.match_no_sk_file));
+		if (len >= char_count) {
+			*outp = '\0';
+			return outp - page;
+		}
+		outp += len;
+		char_count -= len;
+		(*num_items_returned)++;
+	}
+
+	/* Count the following as part of the last item_index */
+	if (item_index > items_to_skip) {
+		prdebug_full_state(indent_level, "proc ctrl");
+	}
+
+	*eof = 1;
+	return outp - page;
+}
+
+/*
+ * Delete socket tags, and stat tags associated with a given
+ * accouting tag and uid.
+ */
+static int ctrl_cmd_delete(const char *input)
+{
+	char cmd;
+	uid_t uid;
+	uid_t entry_uid;
+	tag_t acct_tag;
+	tag_t tag;
+	int res, argc;
+	struct iface_stat *iface_entry;
+	struct rb_node *node;
+	struct sock_tag *st_entry;
+	struct rb_root st_to_free_tree = RB_ROOT;
+	struct tag_stat *ts_entry;
+	struct tag_counter_set *tcs_entry;
+	struct tag_ref *tr_entry;
+	struct uid_tag_data *utd_entry;
+
+	argc = sscanf(input, "%c %llu %u", &cmd, &acct_tag, &uid);
+	CT_DEBUG("qtaguid: ctrl_delete(%s): argc=%d cmd=%c "
+		 "user_tag=0x%llx uid=%u\n", input, argc, cmd,
+		 acct_tag, uid);
+	if (argc < 2) {
+		res = -EINVAL;
+		goto err;
+	}
+	if (!valid_atag(acct_tag)) {
+		pr_info("qtaguid: ctrl_delete(%s): invalid tag\n", input);
+		res = -EINVAL;
+		goto err;
+	}
+	if (argc < 3) {
+		uid = current_fsuid();
+	} else if (!can_impersonate_uid(uid)) {
+		pr_info("qtaguid: ctrl_delete(%s): "
+			"insufficient priv from pid=%u tgid=%u uid=%u\n",
+			input, current->pid, current->tgid, current_fsuid());
+		res = -EPERM;
+		goto err;
+	}
+
+	tag = combine_atag_with_uid(acct_tag, uid);
+	CT_DEBUG("qtaguid: ctrl_delete(%s): "
+		 "looking for tag=0x%llx (uid=%u)\n",
+		 input, tag, uid);
+
+	/* Delete socket tags */
+	spin_lock_bh(&sock_tag_list_lock);
+	node = rb_first(&sock_tag_tree);
+	while (node) {
+		st_entry = rb_entry(node, struct sock_tag, sock_node);
+		entry_uid = get_uid_from_tag(st_entry->tag);
+		node = rb_next(node);
+		if (entry_uid != uid)
+			continue;
+
+		CT_DEBUG("qtaguid: ctrl_delete(%s): st tag=0x%llx (uid=%u)\n",
+			 input, st_entry->tag, entry_uid);
+
+		if (!acct_tag || st_entry->tag == tag) {
+			rb_erase(&st_entry->sock_node, &sock_tag_tree);
+			/* Can't sockfd_put() within spinlock, do it later. */
+			sock_tag_tree_insert(st_entry, &st_to_free_tree);
+			tr_entry = lookup_tag_ref(st_entry->tag, NULL);
+			BUG_ON(tr_entry->num_sock_tags <= 0);
+			tr_entry->num_sock_tags--;
+			/*
+			 * TODO: remove if, and start failing.
+			 * This is a hack to work around the fact that in some
+			 * places we have "if (IS_ERR_OR_NULL(pqd_entry))"
+			 * and are trying to work around apps
+			 * that didn't open the /dev/xt_qtaguid.
+			 */
+			if (st_entry->list.next && st_entry->list.prev)
+				list_del(&st_entry->list);
+		}
+	}
+	spin_unlock_bh(&sock_tag_list_lock);
+
+	sock_tag_tree_erase(&st_to_free_tree);
+
+	/* Delete tag counter-sets */
+	spin_lock_bh(&tag_counter_set_list_lock);
+	/* Counter sets are only on the uid tag, not full tag */
+	tcs_entry = tag_counter_set_tree_search(&tag_counter_set_tree, tag);
+	if (tcs_entry) {
+		CT_DEBUG("qtaguid: ctrl_delete(%s): "
+			 "erase tcs: tag=0x%llx (uid=%u) set=%d\n",
+			 input,
+			 tcs_entry->tn.tag,
+			 get_uid_from_tag(tcs_entry->tn.tag),
+			 tcs_entry->active_set);
+		rb_erase(&tcs_entry->tn.node, &tag_counter_set_tree);
+		kfree(tcs_entry);
+	}
+	spin_unlock_bh(&tag_counter_set_list_lock);
+
+	/*
+	 * If acct_tag is 0, then all entries belonging to uid are
+	 * erased.
+	 */
+	spin_lock_bh(&iface_stat_list_lock);
+	list_for_each_entry(iface_entry, &iface_stat_list, list) {
+		spin_lock_bh(&iface_entry->tag_stat_list_lock);
+		node = rb_first(&iface_entry->tag_stat_tree);
+		while (node) {
+			ts_entry = rb_entry(node, struct tag_stat, tn.node);
+			entry_uid = get_uid_from_tag(ts_entry->tn.tag);
+			node = rb_next(node);
+
+			CT_DEBUG("qtaguid: ctrl_delete(%s): "
+				 "ts tag=0x%llx (uid=%u)\n",
+				 input, ts_entry->tn.tag, entry_uid);
+
+			if (entry_uid != uid)
+				continue;
+			if (!acct_tag || ts_entry->tn.tag == tag) {
+				CT_DEBUG("qtaguid: ctrl_delete(%s): "
+					 "erase ts: %s 0x%llx %u\n",
+					 input, iface_entry->ifname,
+					 get_atag_from_tag(ts_entry->tn.tag),
+					 entry_uid);
+				rb_erase(&ts_entry->tn.node,
+					 &iface_entry->tag_stat_tree);
+				kfree(ts_entry);
+			}
+		}
+		spin_unlock_bh(&iface_entry->tag_stat_list_lock);
+	}
+	spin_unlock_bh(&iface_stat_list_lock);
+
+	/* Cleanup the uid_tag_data */
+	spin_lock_bh(&uid_tag_data_tree_lock);
+	node = rb_first(&uid_tag_data_tree);
+	while (node) {
+		utd_entry = rb_entry(node, struct uid_tag_data, node);
+		entry_uid = utd_entry->uid;
+		node = rb_next(node);
+
+		CT_DEBUG("qtaguid: ctrl_delete(%s): "
+			 "utd uid=%u\n",
+			 input, entry_uid);
+
+		if (entry_uid != uid)
+			continue;
+		/*
+		 * Go over the tag_refs, and those that don't have
+		 * sock_tags using them are freed.
+		 */
+		put_tag_ref_tree(tag, utd_entry);
+		put_utd_entry(utd_entry);
+	}
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+
+	atomic64_inc(&qtu_events.delete_cmds);
+	res = 0;
+
+err:
+	return res;
+}
+
+static int ctrl_cmd_counter_set(const char *input)
+{
+	char cmd;
+	uid_t uid = 0;
+	tag_t tag;
+	int res, argc;
+	struct tag_counter_set *tcs;
+	int counter_set;
+
+	argc = sscanf(input, "%c %d %u", &cmd, &counter_set, &uid);
+	CT_DEBUG("qtaguid: ctrl_counterset(%s): argc=%d cmd=%c "
+		 "set=%d uid=%u\n", input, argc, cmd,
+		 counter_set, uid);
+	if (argc != 3) {
+		res = -EINVAL;
+		goto err;
+	}
+	if (counter_set < 0 || counter_set >= IFS_MAX_COUNTER_SETS) {
+		pr_info("qtaguid: ctrl_counterset(%s): invalid counter_set range\n",
+			input);
+		res = -EINVAL;
+		goto err;
+	}
+	if (!can_manipulate_uids()) {
+		pr_info("qtaguid: ctrl_counterset(%s): "
+			"insufficient priv from pid=%u tgid=%u uid=%u\n",
+			input, current->pid, current->tgid, current_fsuid());
+		res = -EPERM;
+		goto err;
+	}
+
+	tag = make_tag_from_uid(uid);
+	spin_lock_bh(&tag_counter_set_list_lock);
+	tcs = tag_counter_set_tree_search(&tag_counter_set_tree, tag);
+	if (!tcs) {
+		tcs = kzalloc(sizeof(*tcs), GFP_ATOMIC);
+		if (!tcs) {
+			spin_unlock_bh(&tag_counter_set_list_lock);
+			pr_err("qtaguid: ctrl_counterset(%s): "
+			       "failed to alloc counter set\n",
+			       input);
+			res = -ENOMEM;
+			goto err;
+		}
+		tcs->tn.tag = tag;
+		tag_counter_set_tree_insert(tcs, &tag_counter_set_tree);
+		CT_DEBUG("qtaguid: ctrl_counterset(%s): added tcs tag=0x%llx "
+			 "(uid=%u) set=%d\n",
+			 input, tag, get_uid_from_tag(tag), counter_set);
+	}
+	tcs->active_set = counter_set;
+	spin_unlock_bh(&tag_counter_set_list_lock);
+	atomic64_inc(&qtu_events.counter_set_changes);
+	res = 0;
+
+err:
+	return res;
+}
+
+static int ctrl_cmd_tag(const char *input)
+{
+	char cmd;
+	int sock_fd = 0;
+	uid_t uid = 0;
+	tag_t acct_tag = make_atag_from_value(0);
+	tag_t full_tag;
+	struct socket *el_socket;
+	int res, argc;
+	struct sock_tag *sock_tag_entry;
+	struct tag_ref *tag_ref_entry;
+	struct uid_tag_data *uid_tag_data_entry;
+	struct proc_qtu_data *pqd_entry;
+
+	/* Unassigned args will get defaulted later. */
+	argc = sscanf(input, "%c %d %llu %u", &cmd, &sock_fd, &acct_tag, &uid);
+	CT_DEBUG("qtaguid: ctrl_tag(%s): argc=%d cmd=%c sock_fd=%d "
+		 "acct_tag=0x%llx uid=%u\n", input, argc, cmd, sock_fd,
+		 acct_tag, uid);
+	if (argc < 2) {
+		res = -EINVAL;
+		goto err;
+	}
+	el_socket = sockfd_lookup(sock_fd, &res);  /* This locks the file */
+	if (!el_socket) {
+		pr_info("qtaguid: ctrl_tag(%s): failed to lookup"
+			" sock_fd=%d err=%d\n", input, sock_fd, res);
+		goto err;
+	}
+	CT_DEBUG("qtaguid: ctrl_tag(%s): socket->...->f_count=%ld ->sk=%p\n",
+		 input, atomic_long_read(&el_socket->file->f_count),
+		 el_socket->sk);
+	if (argc < 3) {
+		acct_tag = make_atag_from_value(0);
+	} else if (!valid_atag(acct_tag)) {
+		pr_info("qtaguid: ctrl_tag(%s): invalid tag\n", input);
+		res = -EINVAL;
+		goto err_put;
+	}
+	CT_DEBUG("qtaguid: ctrl_tag(%s): "
+		 "pid=%u tgid=%u uid=%u euid=%u fsuid=%u "
+		 "in_group=%d in_egroup=%d\n",
+		 input, current->pid, current->tgid, current_uid(),
+		 current_euid(), current_fsuid(),
+		 in_group_p(proc_ctrl_write_gid),
+		 in_egroup_p(proc_ctrl_write_gid));
+	if (argc < 4) {
+		uid = current_fsuid();
+	} else if (!can_impersonate_uid(uid)) {
+		pr_info("qtaguid: ctrl_tag(%s): "
+			"insufficient priv from pid=%u tgid=%u uid=%u\n",
+			input, current->pid, current->tgid, current_fsuid());
+		res = -EPERM;
+		goto err_put;
+	}
+	full_tag = combine_atag_with_uid(acct_tag, uid);
+
+	spin_lock_bh(&sock_tag_list_lock);
+	sock_tag_entry = get_sock_stat_nl(el_socket->sk);
+	tag_ref_entry = get_tag_ref(full_tag, &uid_tag_data_entry);
+	if (IS_ERR(tag_ref_entry)) {
+		res = PTR_ERR(tag_ref_entry);
+		spin_unlock_bh(&sock_tag_list_lock);
+		goto err_put;
+	}
+	tag_ref_entry->num_sock_tags++;
+	if (sock_tag_entry) {
+		struct tag_ref *prev_tag_ref_entry;
+
+		CT_DEBUG("qtaguid: ctrl_tag(%s): retag for sk=%p "
+			 "st@%p ...->f_count=%ld\n",
+			 input, el_socket->sk, sock_tag_entry,
+			 atomic_long_read(&el_socket->file->f_count));
+		/*
+		 * This is a re-tagging, so release the sock_fd that was
+		 * locked at the time of the 1st tagging.
+		 * There is still the ref from this call's sockfd_lookup() so
+		 * it can be done within the spinlock.
+		 */
+		sockfd_put(sock_tag_entry->socket);
+		prev_tag_ref_entry = lookup_tag_ref(sock_tag_entry->tag,
+						    &uid_tag_data_entry);
+		BUG_ON(IS_ERR_OR_NULL(prev_tag_ref_entry));
+		BUG_ON(prev_tag_ref_entry->num_sock_tags <= 0);
+		prev_tag_ref_entry->num_sock_tags--;
+		sock_tag_entry->tag = full_tag;
+	} else {
+		CT_DEBUG("qtaguid: ctrl_tag(%s): newtag for sk=%p\n",
+			 input, el_socket->sk);
+		sock_tag_entry = kzalloc(sizeof(*sock_tag_entry),
+					 GFP_ATOMIC);
+		if (!sock_tag_entry) {
+			pr_err("qtaguid: ctrl_tag(%s): "
+			       "socket tag alloc failed\n",
+			       input);
+			spin_unlock_bh(&sock_tag_list_lock);
+			res = -ENOMEM;
+			goto err_tag_unref_put;
+		}
+		sock_tag_entry->sk = el_socket->sk;
+		sock_tag_entry->socket = el_socket;
+		sock_tag_entry->pid = current->tgid;
+		sock_tag_entry->tag = combine_atag_with_uid(acct_tag,
+							    uid);
+		spin_lock_bh(&uid_tag_data_tree_lock);
+		pqd_entry = proc_qtu_data_tree_search(
+			&proc_qtu_data_tree, current->tgid);
+		/*
+		 * TODO: remove if, and start failing.
+		 * At first, we want to catch user-space code that is not
+		 * opening the /dev/xt_qtaguid.
+		 */
+		if (IS_ERR_OR_NULL(pqd_entry))
+			pr_warn_once(
+				"qtaguid: %s(): "
+				"User space forgot to open /dev/xt_qtaguid? "
+				"pid=%u tgid=%u uid=%u\n", __func__,
+				current->pid, current->tgid,
+				current_fsuid());
+		else
+			list_add(&sock_tag_entry->list,
+				 &pqd_entry->sock_tag_list);
+		spin_unlock_bh(&uid_tag_data_tree_lock);
+
+		sock_tag_tree_insert(sock_tag_entry, &sock_tag_tree);
+		atomic64_inc(&qtu_events.sockets_tagged);
+	}
+	spin_unlock_bh(&sock_tag_list_lock);
+	/* We keep the ref to the socket (file) until it is untagged */
+	CT_DEBUG("qtaguid: ctrl_tag(%s): done st@%p ...->f_count=%ld\n",
+		 input, sock_tag_entry,
+		 atomic_long_read(&el_socket->file->f_count));
+	return 0;
+
+err_tag_unref_put:
+	BUG_ON(tag_ref_entry->num_sock_tags <= 0);
+	tag_ref_entry->num_sock_tags--;
+	free_tag_ref_from_utd_entry(tag_ref_entry, uid_tag_data_entry);
+err_put:
+	CT_DEBUG("qtaguid: ctrl_tag(%s): done. ...->f_count=%ld\n",
+		 input, atomic_long_read(&el_socket->file->f_count) - 1);
+	/* Release the sock_fd that was grabbed by sockfd_lookup(). */
+	sockfd_put(el_socket);
+	return res;
+
+err:
+	CT_DEBUG("qtaguid: ctrl_tag(%s): done.\n", input);
+	return res;
+}
+
+static int ctrl_cmd_untag(const char *input)
+{
+	char cmd;
+	int sock_fd = 0;
+	struct socket *el_socket;
+	int res, argc;
+	struct sock_tag *sock_tag_entry;
+	struct tag_ref *tag_ref_entry;
+	struct uid_tag_data *utd_entry;
+	struct proc_qtu_data *pqd_entry;
+
+	argc = sscanf(input, "%c %d", &cmd, &sock_fd);
+	CT_DEBUG("qtaguid: ctrl_untag(%s): argc=%d cmd=%c sock_fd=%d\n",
+		 input, argc, cmd, sock_fd);
+	if (argc < 2) {
+		res = -EINVAL;
+		goto err;
+	}
+	el_socket = sockfd_lookup(sock_fd, &res);  /* This locks the file */
+	if (!el_socket) {
+		pr_info("qtaguid: ctrl_untag(%s): failed to lookup"
+			" sock_fd=%d err=%d\n", input, sock_fd, res);
+		goto err;
+	}
+	CT_DEBUG("qtaguid: ctrl_untag(%s): socket->...->f_count=%ld ->sk=%p\n",
+		 input, atomic_long_read(&el_socket->file->f_count),
+		 el_socket->sk);
+	spin_lock_bh(&sock_tag_list_lock);
+	sock_tag_entry = get_sock_stat_nl(el_socket->sk);
+	if (!sock_tag_entry) {
+		spin_unlock_bh(&sock_tag_list_lock);
+		res = -EINVAL;
+		goto err_put;
+	}
+	/*
+	 * The socket already belongs to the current process
+	 * so it can do whatever it wants to it.
+	 */
+	rb_erase(&sock_tag_entry->sock_node, &sock_tag_tree);
+
+	tag_ref_entry = lookup_tag_ref(sock_tag_entry->tag, &utd_entry);
+	BUG_ON(!tag_ref_entry);
+	BUG_ON(tag_ref_entry->num_sock_tags <= 0);
+	spin_lock_bh(&uid_tag_data_tree_lock);
+	pqd_entry = proc_qtu_data_tree_search(
+		&proc_qtu_data_tree, current->tgid);
+	/*
+	 * TODO: remove if, and start failing.
+	 * At first, we want to catch user-space code that is not
+	 * opening the /dev/xt_qtaguid.
+	 */
+	if (IS_ERR_OR_NULL(pqd_entry))
+		pr_warn_once("qtaguid: %s(): "
+			     "User space forgot to open /dev/xt_qtaguid? "
+			     "pid=%u tgid=%u uid=%u\n", __func__,
+			     current->pid, current->tgid, current_fsuid());
+	else
+		list_del(&sock_tag_entry->list);
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+	/*
+	 * We don't free tag_ref from the utd_entry here,
+	 * only during a cmd_delete().
+	 */
+	tag_ref_entry->num_sock_tags--;
+	spin_unlock_bh(&sock_tag_list_lock);
+	/*
+	 * Release the sock_fd that was grabbed at tag time,
+	 * and once more for the sockfd_lookup() here.
+	 */
+	sockfd_put(sock_tag_entry->socket);
+	CT_DEBUG("qtaguid: ctrl_untag(%s): done. st@%p ...->f_count=%ld\n",
+		 input, sock_tag_entry,
+		 atomic_long_read(&el_socket->file->f_count) - 1);
+	sockfd_put(el_socket);
+
+	kfree(sock_tag_entry);
+	atomic64_inc(&qtu_events.sockets_untagged);
+
+	return 0;
+
+err_put:
+	CT_DEBUG("qtaguid: ctrl_untag(%s): done. socket->...->f_count=%ld\n",
+		 input, atomic_long_read(&el_socket->file->f_count) - 1);
+	/* Release the sock_fd that was grabbed by sockfd_lookup(). */
+	sockfd_put(el_socket);
+	return res;
+
+err:
+	CT_DEBUG("qtaguid: ctrl_untag(%s): done.\n", input);
+	return res;
+}
+
+static int qtaguid_ctrl_parse(const char *input, int count)
+{
+	char cmd;
+	int res;
+
+	cmd = input[0];
+	/* Collect params for commands */
+	switch (cmd) {
+	case 'd':
+		res = ctrl_cmd_delete(input);
+		break;
+
+	case 's':
+		res = ctrl_cmd_counter_set(input);
+		break;
+
+	case 't':
+		res = ctrl_cmd_tag(input);
+		break;
+
+	case 'u':
+		res = ctrl_cmd_untag(input);
+		break;
+
+	default:
+		res = -EINVAL;
+		goto err;
+	}
+	if (!res)
+		res = count;
+err:
+	CT_DEBUG("qtaguid: ctrl(%s): res=%d\n", input, res);
+	return res;
+}
+
+#define MAX_QTAGUID_CTRL_INPUT_LEN 255
+static int qtaguid_ctrl_proc_write(struct file *file, const char __user *buffer,
+			unsigned long count, void *data)
+{
+	char input_buf[MAX_QTAGUID_CTRL_INPUT_LEN];
+
+	if (unlikely(module_passive))
+		return count;
+
+	if (count >= MAX_QTAGUID_CTRL_INPUT_LEN)
+		return -EINVAL;
+
+	if (copy_from_user(input_buf, buffer, count))
+		return -EFAULT;
+
+	input_buf[count] = '\0';
+	return qtaguid_ctrl_parse(input_buf, count);
+}
+
+struct proc_print_info {
+	char *outp;
+	char **num_items_returned;
+	struct iface_stat *iface_entry;
+	struct tag_stat *ts_entry;
+	int item_index;
+	int items_to_skip;
+	int char_count;
+};
+
+static int pp_stats_line(struct proc_print_info *ppi, int cnt_set)
+{
+	int len;
+	struct data_counters *cnts;
+
+	if (!ppi->item_index) {
+		if (ppi->item_index++ < ppi->items_to_skip)
+			return 0;
+		len = snprintf(ppi->outp, ppi->char_count,
+			       "idx iface acct_tag_hex uid_tag_int cnt_set "
+			       "rx_bytes rx_packets "
+			       "tx_bytes tx_packets "
+			       "rx_tcp_bytes rx_tcp_packets "
+			       "rx_udp_bytes rx_udp_packets "
+			       "rx_other_bytes rx_other_packets "
+			       "tx_tcp_bytes tx_tcp_packets "
+			       "tx_udp_bytes tx_udp_packets "
+			       "tx_other_bytes tx_other_packets\n");
+	} else {
+		tag_t tag = ppi->ts_entry->tn.tag;
+		uid_t stat_uid = get_uid_from_tag(tag);
+
+		if (!can_read_other_uid_stats(stat_uid)) {
+			CT_DEBUG("qtaguid: stats line: "
+				 "%s 0x%llx %u: insufficient priv "
+				 "from pid=%u tgid=%u uid=%u\n",
+				 ppi->iface_entry->ifname,
+				 get_atag_from_tag(tag), stat_uid,
+				 current->pid, current->tgid, current_fsuid());
+			return 0;
+		}
+		if (ppi->item_index++ < ppi->items_to_skip)
+			return 0;
+		cnts = &ppi->ts_entry->counters;
+		len = snprintf(
+			ppi->outp, ppi->char_count,
+			"%d %s 0x%llx %u %u "
+			"%llu %llu "
+			"%llu %llu "
+			"%llu %llu "
+			"%llu %llu "
+			"%llu %llu "
+			"%llu %llu "
+			"%llu %llu "
+			"%llu %llu\n",
+			ppi->item_index,
+			ppi->iface_entry->ifname,
+			get_atag_from_tag(tag),
+			stat_uid,
+			cnt_set,
+			dc_sum_bytes(cnts, cnt_set, IFS_RX),
+			dc_sum_packets(cnts, cnt_set, IFS_RX),
+			dc_sum_bytes(cnts, cnt_set, IFS_TX),
+			dc_sum_packets(cnts, cnt_set, IFS_TX),
+			cnts->bpc[cnt_set][IFS_RX][IFS_TCP].bytes,
+			cnts->bpc[cnt_set][IFS_RX][IFS_TCP].packets,
+			cnts->bpc[cnt_set][IFS_RX][IFS_UDP].bytes,
+			cnts->bpc[cnt_set][IFS_RX][IFS_UDP].packets,
+			cnts->bpc[cnt_set][IFS_RX][IFS_PROTO_OTHER].bytes,
+			cnts->bpc[cnt_set][IFS_RX][IFS_PROTO_OTHER].packets,
+			cnts->bpc[cnt_set][IFS_TX][IFS_TCP].bytes,
+			cnts->bpc[cnt_set][IFS_TX][IFS_TCP].packets,
+			cnts->bpc[cnt_set][IFS_TX][IFS_UDP].bytes,
+			cnts->bpc[cnt_set][IFS_TX][IFS_UDP].packets,
+			cnts->bpc[cnt_set][IFS_TX][IFS_PROTO_OTHER].bytes,
+			cnts->bpc[cnt_set][IFS_TX][IFS_PROTO_OTHER].packets);
+	}
+	return len;
+}
+
+static bool pp_sets(struct proc_print_info *ppi)
+{
+	int len;
+	int counter_set;
+	for (counter_set = 0; counter_set < IFS_MAX_COUNTER_SETS;
+	     counter_set++) {
+		len = pp_stats_line(ppi, counter_set);
+		if (len >= ppi->char_count) {
+			*ppi->outp = '\0';
+			return false;
+		}
+		if (len) {
+			ppi->outp += len;
+			ppi->char_count -= len;
+			(*ppi->num_items_returned)++;
+		}
+	}
+	return true;
+}
+
+/*
+ * Procfs reader to get all tag stats using style "1)" as described in
+ * fs/proc/generic.c
+ * Groups all protocols tx/rx bytes.
+ */
+static int qtaguid_stats_proc_read(char *page, char **num_items_returned,
+				off_t items_to_skip, int char_count, int *eof,
+				void *data)
+{
+	struct proc_print_info ppi;
+	int len;
+
+	ppi.outp = page;
+	ppi.item_index = 0;
+	ppi.char_count = char_count;
+	ppi.num_items_returned = num_items_returned;
+	ppi.items_to_skip = items_to_skip;
+
+	if (unlikely(module_passive)) {
+		len = pp_stats_line(&ppi, 0);
+		/* The header should always be shorter than the buffer. */
+		BUG_ON(len >= ppi.char_count);
+		(*num_items_returned)++;
+		*eof = 1;
+		return len;
+	}
+
+	CT_DEBUG("qtaguid:proc stats page=%p *num_items_returned=%p off=%ld "
+		"char_count=%d *eof=%d\n", page, *num_items_returned,
+		items_to_skip, char_count, *eof);
+
+	if (*eof)
+		return 0;
+
+	/* The idx is there to help debug when things go belly up. */
+	len = pp_stats_line(&ppi, 0);
+	/* Don't advance the outp unless the whole line was printed */
+	if (len >= ppi.char_count) {
+		*ppi.outp = '\0';
+		return ppi.outp - page;
+	}
+	if (len) {
+		ppi.outp += len;
+		ppi.char_count -= len;
+		(*num_items_returned)++;
+	}
+
+	spin_lock_bh(&iface_stat_list_lock);
+	list_for_each_entry(ppi.iface_entry, &iface_stat_list, list) {
+		struct rb_node *node;
+		spin_lock_bh(&ppi.iface_entry->tag_stat_list_lock);
+		for (node = rb_first(&ppi.iface_entry->tag_stat_tree);
+		     node;
+		     node = rb_next(node)) {
+			ppi.ts_entry = rb_entry(node, struct tag_stat, tn.node);
+			if (!pp_sets(&ppi)) {
+				spin_unlock_bh(
+					&ppi.iface_entry->tag_stat_list_lock);
+				spin_unlock_bh(&iface_stat_list_lock);
+				return ppi.outp - page;
+			}
+		}
+		spin_unlock_bh(&ppi.iface_entry->tag_stat_list_lock);
+	}
+	spin_unlock_bh(&iface_stat_list_lock);
+
+	*eof = 1;
+	return ppi.outp - page;
+}
+
+/*------------------------------------------*/
+static int qtudev_open(struct inode *inode, struct file *file)
+{
+	struct uid_tag_data *utd_entry;
+	struct proc_qtu_data  *pqd_entry;
+	struct proc_qtu_data  *new_pqd_entry;
+	int res;
+	bool utd_entry_found;
+
+	if (unlikely(qtu_proc_handling_passive))
+		return 0;
+
+	DR_DEBUG("qtaguid: qtudev_open(): pid=%u tgid=%u uid=%u\n",
+		 current->pid, current->tgid, current_fsuid());
+
+	spin_lock_bh(&uid_tag_data_tree_lock);
+
+	/* Look for existing uid data, or alloc one. */
+	utd_entry = get_uid_data(current_fsuid(), &utd_entry_found);
+	if (IS_ERR_OR_NULL(utd_entry)) {
+		res = PTR_ERR(utd_entry);
+		goto err;
+	}
+
+	/* Look for existing PID based proc_data */
+	pqd_entry = proc_qtu_data_tree_search(&proc_qtu_data_tree,
+					      current->tgid);
+	if (pqd_entry) {
+		pr_err("qtaguid: qtudev_open(): %u/%u %u "
+		       "%s already opened\n",
+		       current->pid, current->tgid, current_fsuid(),
+		       QTU_DEV_NAME);
+		res = -EBUSY;
+		goto err_unlock_free_utd;
+	}
+
+	new_pqd_entry = kzalloc(sizeof(*new_pqd_entry), GFP_ATOMIC);
+	if (!new_pqd_entry) {
+		pr_err("qtaguid: qtudev_open(): %u/%u %u: "
+		       "proc data alloc failed\n",
+		       current->pid, current->tgid, current_fsuid());
+		res = -ENOMEM;
+		goto err_unlock_free_utd;
+	}
+	new_pqd_entry->pid = current->tgid;
+	INIT_LIST_HEAD(&new_pqd_entry->sock_tag_list);
+	new_pqd_entry->parent_tag_data = utd_entry;
+	utd_entry->num_pqd++;
+
+	proc_qtu_data_tree_insert(new_pqd_entry,
+				  &proc_qtu_data_tree);
+
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+	DR_DEBUG("qtaguid: tracking data for uid=%u in pqd=%p\n",
+		 current_fsuid(), new_pqd_entry);
+	file->private_data = new_pqd_entry;
+	return 0;
+
+err_unlock_free_utd:
+	if (!utd_entry_found) {
+		rb_erase(&utd_entry->node, &uid_tag_data_tree);
+		kfree(utd_entry);
+	}
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+err:
+	return res;
+}
+
+static int qtudev_release(struct inode *inode, struct file *file)
+{
+	struct proc_qtu_data  *pqd_entry = file->private_data;
+	struct uid_tag_data  *utd_entry = pqd_entry->parent_tag_data;
+	struct sock_tag *st_entry;
+	struct rb_root st_to_free_tree = RB_ROOT;
+	struct list_head *entry, *next;
+	struct tag_ref *tr;
+
+	if (unlikely(qtu_proc_handling_passive))
+		return 0;
+
+	/*
+	 * Do not trust the current->pid, it might just be a kworker cleaning
+	 * up after a dead proc.
+	 */
+	DR_DEBUG("qtaguid: qtudev_release(): "
+		 "pid=%u tgid=%u uid=%u "
+		 "pqd_entry=%p->pid=%u utd_entry=%p->active_tags=%d\n",
+		 current->pid, current->tgid, pqd_entry->parent_tag_data->uid,
+		 pqd_entry, pqd_entry->pid, utd_entry,
+		 utd_entry->num_active_tags);
+
+	spin_lock_bh(&sock_tag_list_lock);
+	spin_lock_bh(&uid_tag_data_tree_lock);
+
+	list_for_each_safe(entry, next, &pqd_entry->sock_tag_list) {
+		st_entry = list_entry(entry, struct sock_tag, list);
+		DR_DEBUG("qtaguid: %s(): "
+			 "erase sock_tag=%p->sk=%p pid=%u tgid=%u uid=%u\n",
+			 __func__,
+			 st_entry, st_entry->sk,
+			 current->pid, current->tgid,
+			 pqd_entry->parent_tag_data->uid);
+
+		utd_entry = uid_tag_data_tree_search(
+			&uid_tag_data_tree,
+			get_uid_from_tag(st_entry->tag));
+		BUG_ON(IS_ERR_OR_NULL(utd_entry));
+		DR_DEBUG("qtaguid: %s(): "
+			 "looking for tag=0x%llx in utd_entry=%p\n", __func__,
+			 st_entry->tag, utd_entry);
+		tr = tag_ref_tree_search(&utd_entry->tag_ref_tree,
+					 st_entry->tag);
+		BUG_ON(!tr);
+		BUG_ON(tr->num_sock_tags <= 0);
+		tr->num_sock_tags--;
+		free_tag_ref_from_utd_entry(tr, utd_entry);
+
+		rb_erase(&st_entry->sock_node, &sock_tag_tree);
+		list_del(&st_entry->list);
+		/* Can't sockfd_put() within spinlock, do it later. */
+		sock_tag_tree_insert(st_entry, &st_to_free_tree);
+
+		/*
+		 * Try to free the utd_entry if no other proc_qtu_data is
+		 * using it (num_pqd is 0) and it doesn't have active tags
+		 * (num_active_tags is 0).
+		 */
+		put_utd_entry(utd_entry);
+	}
+
+	rb_erase(&pqd_entry->node, &proc_qtu_data_tree);
+	BUG_ON(pqd_entry->parent_tag_data->num_pqd < 1);
+	pqd_entry->parent_tag_data->num_pqd--;
+	put_utd_entry(pqd_entry->parent_tag_data);
+	kfree(pqd_entry);
+	file->private_data = NULL;
+
+	spin_unlock_bh(&uid_tag_data_tree_lock);
+	spin_unlock_bh(&sock_tag_list_lock);
+
+
+	sock_tag_tree_erase(&st_to_free_tree);
+
+	prdebug_full_state(0, "%s(): pid=%u tgid=%u", __func__,
+			   current->pid, current->tgid);
+	return 0;
+}
+
+/*------------------------------------------*/
+static const struct file_operations qtudev_fops = {
+	.owner = THIS_MODULE,
+	.open = qtudev_open,
+	.release = qtudev_release,
+};
+
+static struct miscdevice qtu_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = QTU_DEV_NAME,
+	.fops = &qtudev_fops,
+	/* How sad it doesn't allow for defaults: .mode = S_IRUGO | S_IWUSR */
+};
+
+/*------------------------------------------*/
+static int __init qtaguid_proc_register(struct proc_dir_entry **res_procdir)
+{
+	int ret;
+	*res_procdir = proc_mkdir(module_procdirname, init_net.proc_net);
+	if (!*res_procdir) {
+		pr_err("qtaguid: failed to create proc/.../xt_qtaguid\n");
+		ret = -ENOMEM;
+		goto no_dir;
+	}
+
+	xt_qtaguid_ctrl_file = create_proc_entry("ctrl", proc_ctrl_perms,
+						*res_procdir);
+	if (!xt_qtaguid_ctrl_file) {
+		pr_err("qtaguid: failed to create xt_qtaguid/ctrl "
+			" file\n");
+		ret = -ENOMEM;
+		goto no_ctrl_entry;
+	}
+	xt_qtaguid_ctrl_file->read_proc = qtaguid_ctrl_proc_read;
+	xt_qtaguid_ctrl_file->write_proc = qtaguid_ctrl_proc_write;
+
+	xt_qtaguid_stats_file = create_proc_entry("stats", proc_stats_perms,
+						*res_procdir);
+	if (!xt_qtaguid_stats_file) {
+		pr_err("qtaguid: failed to create xt_qtaguid/stats "
+			"file\n");
+		ret = -ENOMEM;
+		goto no_stats_entry;
+	}
+	xt_qtaguid_stats_file->read_proc = qtaguid_stats_proc_read;
+	/*
+	 * TODO: add support counter hacking
+	 * xt_qtaguid_stats_file->write_proc = qtaguid_stats_proc_write;
+	 */
+	return 0;
+
+no_stats_entry:
+	remove_proc_entry("ctrl", *res_procdir);
+no_ctrl_entry:
+	remove_proc_entry("xt_qtaguid", NULL);
+no_dir:
+	return ret;
+}
+
+static struct xt_match qtaguid_mt_reg __read_mostly = {
+	/*
+	 * This module masquerades as the "owner" module so that iptables
+	 * tools can deal with it.
+	 */
+	.name       = "owner",
+	.revision   = 1,
+	.family     = NFPROTO_UNSPEC,
+	.match      = qtaguid_mt,
+	.matchsize  = sizeof(struct xt_qtaguid_match_info),
+	.me         = THIS_MODULE,
+};
+
+static int __init qtaguid_mt_init(void)
+{
+	if (qtaguid_proc_register(&xt_qtaguid_procdir)
+	    || iface_stat_init(xt_qtaguid_procdir)
+	    || xt_register_match(&qtaguid_mt_reg)
+	    || misc_register(&qtu_device))
+		return -1;
+	return 0;
+}
+
+/*
+ * TODO: allow unloading of the module.
+ * For now stats are permanent.
+ * Kconfig forces'y/n' and never an 'm'.
+ */
+
+module_init(qtaguid_mt_init);
+MODULE_AUTHOR("jpa <jpa@google.com>");
+MODULE_DESCRIPTION("Xtables: socket owner+tag matching and associated stats");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_owner");
+MODULE_ALIAS("ip6t_owner");
+MODULE_ALIAS("ipt_qtaguid");
+MODULE_ALIAS("ip6t_qtaguid");
diff --git a/net/netfilter/xt_qtaguid_internal.h b/net/netfilter/xt_qtaguid_internal.h
new file mode 100644
index 0000000..02479d6
--- /dev/null
+++ b/net/netfilter/xt_qtaguid_internal.h
@@ -0,0 +1,330 @@
+/*
+ * Kernel iptables module to track stats for packets based on user tags.
+ *
+ * (C) 2011 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __XT_QTAGUID_INTERNAL_H__
+#define __XT_QTAGUID_INTERNAL_H__
+
+#include <linux/types.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock_types.h>
+#include <linux/workqueue.h>
+
+/* Iface handling */
+#define IDEBUG_MASK (1<<0)
+/* Iptable Matching. Per packet. */
+#define MDEBUG_MASK (1<<1)
+/* Red-black tree handling. Per packet. */
+#define RDEBUG_MASK (1<<2)
+/* procfs ctrl/stats handling */
+#define CDEBUG_MASK (1<<3)
+/* dev and resource tracking */
+#define DDEBUG_MASK (1<<4)
+
+/* E.g (IDEBUG_MASK | CDEBUG_MASK | DDEBUG_MASK) */
+#define DEFAULT_DEBUG_MASK 0
+
+/*
+ * (Un)Define these *DEBUG to compile out/in the pr_debug calls.
+ * All undef: text size ~ 0x3030; all def: ~ 0x4404.
+ */
+#define IDEBUG
+#define MDEBUG
+#define RDEBUG
+#define CDEBUG
+#define DDEBUG
+
+#define MSK_DEBUG(mask, ...) do {                           \
+		if (unlikely(qtaguid_debug_mask & (mask)))  \
+			pr_debug(__VA_ARGS__);              \
+	} while (0)
+#ifdef IDEBUG
+#define IF_DEBUG(...) MSK_DEBUG(IDEBUG_MASK, __VA_ARGS__)
+#else
+#define IF_DEBUG(...) no_printk(__VA_ARGS__)
+#endif
+#ifdef MDEBUG
+#define MT_DEBUG(...) MSK_DEBUG(MDEBUG_MASK, __VA_ARGS__)
+#else
+#define MT_DEBUG(...) no_printk(__VA_ARGS__)
+#endif
+#ifdef RDEBUG
+#define RB_DEBUG(...) MSK_DEBUG(RDEBUG_MASK, __VA_ARGS__)
+#else
+#define RB_DEBUG(...) no_printk(__VA_ARGS__)
+#endif
+#ifdef CDEBUG
+#define CT_DEBUG(...) MSK_DEBUG(CDEBUG_MASK, __VA_ARGS__)
+#else
+#define CT_DEBUG(...) no_printk(__VA_ARGS__)
+#endif
+#ifdef DDEBUG
+#define DR_DEBUG(...) MSK_DEBUG(DDEBUG_MASK, __VA_ARGS__)
+#else
+#define DR_DEBUG(...) no_printk(__VA_ARGS__)
+#endif
+
+extern uint qtaguid_debug_mask;
+
+/*---------------------------------------------------------------------------*/
+/*
+ * Tags:
+ *
+ * They represent what the data usage counters will be tracked against.
+ * By default a tag is just based on the UID.
+ * The UID is used as the base for policing, and can not be ignored.
+ * So a tag will always at least represent a UID (uid_tag).
+ *
+ * A tag can be augmented with an "accounting tag" which is associated
+ * with a UID.
+ * User space can set the acct_tag portion of the tag which is then used
+ * with sockets: all data belonging to that socket will be counted against the
+ * tag. The policing is then based on the tag's uid_tag portion,
+ * and stats are collected for the acct_tag portion separately.
+ *
+ * There could be
+ * a:  {acct_tag=1, uid_tag=10003}
+ * b:  {acct_tag=2, uid_tag=10003}
+ * c:  {acct_tag=3, uid_tag=10003}
+ * d:  {acct_tag=0, uid_tag=10003}
+ * a, b, and c represent tags associated with specific sockets.
+ * d is for the totals for that uid, including all untagged traffic.
+ * Typically d is used with policing/quota rules.
+ *
+ * We want tag_t big enough to distinguish uid_t and acct_tag.
+ * It might become a struct if needed.
+ * Nothing should be using it as an int.
+ */
+typedef uint64_t tag_t;  /* Only used via accessors */
+
+#define TAG_UID_MASK 0xFFFFFFFFULL
+#define TAG_ACCT_MASK (~0xFFFFFFFFULL)
+
+static inline int tag_compare(tag_t t1, tag_t t2)
+{
+	return t1 < t2 ? -1 : t1 == t2 ? 0 : 1;
+}
+
+static inline tag_t combine_atag_with_uid(tag_t acct_tag, uid_t uid)
+{
+	return acct_tag | uid;
+}
+static inline tag_t make_tag_from_uid(uid_t uid)
+{
+	return uid;
+}
+static inline uid_t get_uid_from_tag(tag_t tag)
+{
+	return tag & TAG_UID_MASK;
+}
+static inline tag_t get_utag_from_tag(tag_t tag)
+{
+	return tag & TAG_UID_MASK;
+}
+static inline tag_t get_atag_from_tag(tag_t tag)
+{
+	return tag & TAG_ACCT_MASK;
+}
+
+static inline bool valid_atag(tag_t tag)
+{
+	return !(tag & TAG_UID_MASK);
+}
+static inline tag_t make_atag_from_value(uint32_t value)
+{
+	return (uint64_t)value << 32;
+}
+/*---------------------------------------------------------------------------*/
+
+/*
+ * Maximum number of socket tags that a UID is allowed to have active.
+ * Multiple processes belonging to the same UID contribute towards this limit.
+ * Special UIDs that can impersonate a UID also contribute (e.g. download
+ * manager, ...)
+ */
+#define DEFAULT_MAX_SOCK_TAGS 1024
+
+/*
+ * For now we only track 2 sets of counters.
+ * The default set is 0.
+ * Userspace can activate another set for a given uid being tracked.
+ */
+#define IFS_MAX_COUNTER_SETS 2
+
+enum ifs_tx_rx {
+	IFS_TX,
+	IFS_RX,
+	IFS_MAX_DIRECTIONS
+};
+
+/* For now, TCP, UDP, the rest */
+enum ifs_proto {
+	IFS_TCP,
+	IFS_UDP,
+	IFS_PROTO_OTHER,
+	IFS_MAX_PROTOS
+};
+
+struct byte_packet_counters {
+	uint64_t bytes;
+	uint64_t packets;
+};
+
+struct data_counters {
+	struct byte_packet_counters bpc[IFS_MAX_COUNTER_SETS][IFS_MAX_DIRECTIONS][IFS_MAX_PROTOS];
+};
+
+/* Generic X based nodes used as a base for rb_tree ops */
+struct tag_node {
+	struct rb_node node;
+	tag_t tag;
+};
+
+struct tag_stat {
+	struct tag_node tn;
+	struct data_counters counters;
+	/*
+	 * If this tag is acct_tag based, we need to count against the
+	 * matching parent uid_tag.
+	 */
+	struct data_counters *parent_counters;
+};
+
+struct iface_stat {
+	struct list_head list;  /* in iface_stat_list */
+	char *ifname;
+	bool active;
+	/* net_dev is only valid for active iface_stat */
+	struct net_device *net_dev;
+
+	struct byte_packet_counters totals[IFS_MAX_DIRECTIONS];
+	/*
+	 * We keep the last_known, because some devices reset their counters
+	 * just before NETDEV_UP, while some will reset just before
+	 * NETDEV_REGISTER (which is more normal).
+	 * So now, if the device didn't do a NETDEV_UNREGISTER and we see
+	 * its current dev stats smaller that what was previously known, we
+	 * assume an UNREGISTER and just use the last_known.
+	 */
+	struct byte_packet_counters last_known[IFS_MAX_DIRECTIONS];
+	/* last_known is usable when last_known_valid is true */
+	bool last_known_valid;
+
+	struct proc_dir_entry *proc_ptr;
+
+	struct rb_root tag_stat_tree;
+	spinlock_t tag_stat_list_lock;
+};
+
+/* This is needed to create proc_dir_entries from atomic context. */
+struct iface_stat_work {
+	struct work_struct iface_work;
+	struct iface_stat *iface_entry;
+};
+
+/*
+ * Track tag that this socket is transferring data for, and not necessarily
+ * the uid that owns the socket.
+ * This is the tag against which tag_stat.counters will be billed.
+ * These structs need to be looked up by sock and pid.
+ */
+struct sock_tag {
+	struct rb_node sock_node;
+	struct sock *sk;  /* Only used as a number, never dereferenced */
+	/* The socket is needed for sockfd_put() */
+	struct socket *socket;
+	/* Used to associate with a given pid */
+	struct list_head list;   /* in proc_qtu_data.sock_tag_list */
+	pid_t pid;
+
+	tag_t tag;
+};
+
+struct qtaguid_event_counts {
+	/* Various successful events */
+	atomic64_t sockets_tagged;
+	atomic64_t sockets_untagged;
+	atomic64_t counter_set_changes;
+	atomic64_t delete_cmds;
+	atomic64_t iface_events;  /* Number of NETDEV_* events handled */
+
+	atomic64_t match_calls;   /* Number of times iptables called mt */
+	/*
+	 * match_found_sk_*: numbers related to the netfilter matching
+	 * function finding a sock for the sk_buff.
+	 * Total skbs processed is sum(match_found*).
+	 */
+	atomic64_t match_found_sk;   /* An sk was already in the sk_buff. */
+	/* The connection tracker had or didn't have the sk. */
+	atomic64_t match_found_sk_in_ct;
+	atomic64_t match_found_no_sk_in_ct;
+	/*
+	 * No sk could be found. No apparent owner. Could happen with
+	 * unsolicited traffic.
+	 */
+	atomic64_t match_no_sk;
+	/*
+	 * The file ptr in the sk_socket wasn't there.
+	 * This might happen for traffic while the socket is being closed.
+	 */
+	atomic64_t match_no_sk_file;
+};
+
+/* Track the set active_set for the given tag. */
+struct tag_counter_set {
+	struct tag_node tn;
+	int active_set;
+};
+
+/*----------------------------------------------*/
+/*
+ * The qtu uid data is used to track resources that are created directly or
+ * indirectly by processes (uid tracked).
+ * It is shared by the processes with the same uid.
+ * Some of the resource will be counted to prevent further rogue allocations,
+ * some will need freeing once the owner process (uid) exits.
+ */
+struct uid_tag_data {
+	struct rb_node node;
+	uid_t uid;
+
+	/*
+	 * For the uid, how many accounting tags have been set.
+	 */
+	int num_active_tags;
+	/* Track the number of proc_qtu_data that reference it */
+	int num_pqd;
+	struct rb_root tag_ref_tree;
+	/* No tag_node_tree_lock; use uid_tag_data_tree_lock */
+};
+
+struct tag_ref {
+	struct tag_node tn;
+
+	/*
+	 * This tracks the number of active sockets that have a tag on them
+	 * which matches this tag_ref.tn.tag.
+	 * A tag ref can live on after the sockets are untagged.
+	 * A tag ref can only be removed during a tag delete command.
+	 */
+	int num_sock_tags;
+};
+
+struct proc_qtu_data {
+	struct rb_node node;
+	pid_t pid;
+
+	struct uid_tag_data *parent_tag_data;
+
+	/* Tracks the sock_tags that need freeing upon this proc's death */
+	struct list_head sock_tag_list;
+	/* No spinlock_t sock_tag_list_lock; use the global one. */
+};
+
+/*----------------------------------------------*/
+#endif  /* ifndef __XT_QTAGUID_INTERNAL_H__ */
diff --git a/net/netfilter/xt_qtaguid_print.c b/net/netfilter/xt_qtaguid_print.c
new file mode 100644
index 0000000..3917678
--- /dev/null
+++ b/net/netfilter/xt_qtaguid_print.c
@@ -0,0 +1,556 @@
+/*
+ * Pretty printing Support for iptables xt_qtaguid module.
+ *
+ * (C) 2011 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * Most of the functions in this file just waste time if DEBUG is not defined.
+ * The matching xt_qtaguid_print.h will static inline empty funcs if the needed
+ * debug flags ore not defined.
+ * Those funcs that fail to allocate memory will panic as there is no need to
+ * hobble allong just pretending to do the requested work.
+ */
+
+#define DEBUG
+
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/net.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/spinlock_types.h>
+
+
+#include "xt_qtaguid_internal.h"
+#include "xt_qtaguid_print.h"
+
+#ifdef DDEBUG
+
+static void _bug_on_err_or_null(void *ptr)
+{
+	if (IS_ERR_OR_NULL(ptr)) {
+		pr_err("qtaguid: kmalloc failed\n");
+		BUG();
+	}
+}
+
+char *pp_tag_t(tag_t *tag)
+{
+	char *res;
+
+	if (!tag)
+		res = kasprintf(GFP_ATOMIC, "tag_t@null{}");
+	else
+		res = kasprintf(GFP_ATOMIC,
+				"tag_t@%p{tag=0x%llx, uid=%u}",
+				tag, *tag, get_uid_from_tag(*tag));
+	_bug_on_err_or_null(res);
+	return res;
+}
+
+char *pp_data_counters(struct data_counters *dc, bool showValues)
+{
+	char *res;
+
+	if (!dc)
+		res = kasprintf(GFP_ATOMIC, "data_counters@null{}");
+	else if (showValues)
+		res = kasprintf(
+			GFP_ATOMIC, "data_counters@%p{"
+			"set0{"
+			"rx{"
+			"tcp{b=%llu, p=%llu}, "
+			"udp{b=%llu, p=%llu},"
+			"other{b=%llu, p=%llu}}, "
+			"tx{"
+			"tcp{b=%llu, p=%llu}, "
+			"udp{b=%llu, p=%llu},"
+			"other{b=%llu, p=%llu}}}, "
+			"set1{"
+			"rx{"
+			"tcp{b=%llu, p=%llu}, "
+			"udp{b=%llu, p=%llu},"
+			"other{b=%llu, p=%llu}}, "
+			"tx{"
+			"tcp{b=%llu, p=%llu}, "
+			"udp{b=%llu, p=%llu},"
+			"other{b=%llu, p=%llu}}}}",
+			dc,
+			dc->bpc[0][IFS_RX][IFS_TCP].bytes,
+			dc->bpc[0][IFS_RX][IFS_TCP].packets,
+			dc->bpc[0][IFS_RX][IFS_UDP].bytes,
+			dc->bpc[0][IFS_RX][IFS_UDP].packets,
+			dc->bpc[0][IFS_RX][IFS_PROTO_OTHER].bytes,
+			dc->bpc[0][IFS_RX][IFS_PROTO_OTHER].packets,
+			dc->bpc[0][IFS_TX][IFS_TCP].bytes,
+			dc->bpc[0][IFS_TX][IFS_TCP].packets,
+			dc->bpc[0][IFS_TX][IFS_UDP].bytes,
+			dc->bpc[0][IFS_TX][IFS_UDP].packets,
+			dc->bpc[0][IFS_TX][IFS_PROTO_OTHER].bytes,
+			dc->bpc[0][IFS_TX][IFS_PROTO_OTHER].packets,
+			dc->bpc[1][IFS_RX][IFS_TCP].bytes,
+			dc->bpc[1][IFS_RX][IFS_TCP].packets,
+			dc->bpc[1][IFS_RX][IFS_UDP].bytes,
+			dc->bpc[1][IFS_RX][IFS_UDP].packets,
+			dc->bpc[1][IFS_RX][IFS_PROTO_OTHER].bytes,
+			dc->bpc[1][IFS_RX][IFS_PROTO_OTHER].packets,
+			dc->bpc[1][IFS_TX][IFS_TCP].bytes,
+			dc->bpc[1][IFS_TX][IFS_TCP].packets,
+			dc->bpc[1][IFS_TX][IFS_UDP].bytes,
+			dc->bpc[1][IFS_TX][IFS_UDP].packets,
+			dc->bpc[1][IFS_TX][IFS_PROTO_OTHER].bytes,
+			dc->bpc[1][IFS_TX][IFS_PROTO_OTHER].packets);
+	else
+		res = kasprintf(GFP_ATOMIC, "data_counters@%p{...}", dc);
+	_bug_on_err_or_null(res);
+	return res;
+}
+
+char *pp_tag_node(struct tag_node *tn)
+{
+	char *tag_str;
+	char *res;
+
+	if (!tn) {
+		res = kasprintf(GFP_ATOMIC, "tag_node@null{}");
+		_bug_on_err_or_null(res);
+		return res;
+	}
+	tag_str = pp_tag_t(&tn->tag);
+	res = kasprintf(GFP_ATOMIC,
+			"tag_node@%p{tag=%s}",
+			tn, tag_str);
+	_bug_on_err_or_null(res);
+	kfree(tag_str);
+	return res;
+}
+
+char *pp_tag_ref(struct tag_ref *tr)
+{
+	char *tn_str;
+	char *res;
+
+	if (!tr) {
+		res = kasprintf(GFP_ATOMIC, "tag_ref@null{}");
+		_bug_on_err_or_null(res);
+		return res;
+	}
+	tn_str = pp_tag_node(&tr->tn);
+	res = kasprintf(GFP_ATOMIC,
+			"tag_ref@%p{%s, num_sock_tags=%d}",
+			tr, tn_str, tr->num_sock_tags);
+	_bug_on_err_or_null(res);
+	kfree(tn_str);
+	return res;
+}
+
+char *pp_tag_stat(struct tag_stat *ts)
+{
+	char *tn_str;
+	char *counters_str;
+	char *parent_counters_str;
+	char *res;
+
+	if (!ts) {
+		res = kasprintf(GFP_ATOMIC, "tag_stat@null{}");
+		_bug_on_err_or_null(res);
+		return res;
+	}
+	tn_str = pp_tag_node(&ts->tn);
+	counters_str = pp_data_counters(&ts->counters, true);
+	parent_counters_str = pp_data_counters(ts->parent_counters, false);
+	res = kasprintf(GFP_ATOMIC,
+			"tag_stat@%p{%s, counters=%s, parent_counters=%s}",
+			ts, tn_str, counters_str, parent_counters_str);
+	_bug_on_err_or_null(res);
+	kfree(tn_str);
+	kfree(counters_str);
+	kfree(parent_counters_str);
+	return res;
+}
+
+char *pp_iface_stat(struct iface_stat *is)
+{
+	char *res;
+	if (!is)
+		res = kasprintf(GFP_ATOMIC, "iface_stat@null{}");
+	else
+		res = kasprintf(GFP_ATOMIC, "iface_stat@%p{"
+				"list=list_head{...}, "
+				"ifname=%s, "
+				"total={rx={bytes=%llu, "
+				"packets=%llu}, "
+				"tx={bytes=%llu, "
+				"packets=%llu}}, "
+				"last_known_valid=%d, "
+				"last_known={rx={bytes=%llu, "
+				"packets=%llu}, "
+				"tx={bytes=%llu, "
+				"packets=%llu}}, "
+				"active=%d, "
+				"net_dev=%p, "
+				"proc_ptr=%p, "
+				"tag_stat_tree=rb_root{...}}",
+				is,
+				is->ifname,
+				is->totals[IFS_RX].bytes,
+				is->totals[IFS_RX].packets,
+				is->totals[IFS_TX].bytes,
+				is->totals[IFS_TX].packets,
+				is->last_known_valid,
+				is->last_known[IFS_RX].bytes,
+				is->last_known[IFS_RX].packets,
+				is->last_known[IFS_TX].bytes,
+				is->last_known[IFS_TX].packets,
+				is->active,
+				is->net_dev,
+				is->proc_ptr);
+	_bug_on_err_or_null(res);
+	return res;
+}
+
+char *pp_sock_tag(struct sock_tag *st)
+{
+	char *tag_str;
+	char *res;
+
+	if (!st) {
+		res = kasprintf(GFP_ATOMIC, "sock_tag@null{}");
+		_bug_on_err_or_null(res);
+		return res;
+	}
+	tag_str = pp_tag_t(&st->tag);
+	res = kasprintf(GFP_ATOMIC, "sock_tag@%p{"
+			"sock_node=rb_node{...}, "
+			"sk=%p socket=%p (f_count=%lu), list=list_head{...}, "
+			"pid=%u, tag=%s}",
+			st, st->sk, st->socket, atomic_long_read(
+				&st->socket->file->f_count),
+			st->pid, tag_str);
+	_bug_on_err_or_null(res);
+	kfree(tag_str);
+	return res;
+}
+
+char *pp_uid_tag_data(struct uid_tag_data *utd)
+{
+	char *res;
+
+	if (!utd)
+		res = kasprintf(GFP_ATOMIC, "uid_tag_data@null{}");
+	else
+		res = kasprintf(GFP_ATOMIC, "uid_tag_data@%p{"
+				"uid=%u, num_active_acct_tags=%d, "
+				"num_pqd=%d, "
+				"tag_node_tree=rb_root{...}, "
+				"proc_qtu_data_tree=rb_root{...}}",
+				utd, utd->uid,
+				utd->num_active_tags, utd->num_pqd);
+	_bug_on_err_or_null(res);
+	return res;
+}
+
+char *pp_proc_qtu_data(struct proc_qtu_data *pqd)
+{
+	char *parent_tag_data_str;
+	char *res;
+
+	if (!pqd) {
+		res = kasprintf(GFP_ATOMIC, "proc_qtu_data@null{}");
+		_bug_on_err_or_null(res);
+		return res;
+	}
+	parent_tag_data_str = pp_uid_tag_data(pqd->parent_tag_data);
+	res = kasprintf(GFP_ATOMIC, "proc_qtu_data@%p{"
+			"node=rb_node{...}, pid=%u, "
+			"parent_tag_data=%s, "
+			"sock_tag_list=list_head{...}}",
+			pqd, pqd->pid, parent_tag_data_str
+		);
+	_bug_on_err_or_null(res);
+	kfree(parent_tag_data_str);
+	return res;
+}
+
+/*------------------------------------------*/
+void prdebug_sock_tag_tree(int indent_level,
+			   struct rb_root *sock_tag_tree)
+{
+	struct rb_node *node;
+	struct sock_tag *sock_tag_entry;
+	char *str;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (RB_EMPTY_ROOT(sock_tag_tree)) {
+		str = "sock_tag_tree=rb_root{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "sock_tag_tree=rb_root{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	for (node = rb_first(sock_tag_tree);
+	     node;
+	     node = rb_next(node)) {
+		sock_tag_entry = rb_entry(node, struct sock_tag, sock_node);
+		str = pp_sock_tag(sock_tag_entry);
+		pr_debug("%*d: %s,\n", indent_level*2, indent_level, str);
+		kfree(str);
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+void prdebug_sock_tag_list(int indent_level,
+			   struct list_head *sock_tag_list)
+{
+	struct sock_tag *sock_tag_entry;
+	char *str;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (list_empty(sock_tag_list)) {
+		str = "sock_tag_list=list_head{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "sock_tag_list=list_head{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	list_for_each_entry(sock_tag_entry, sock_tag_list, list) {
+		str = pp_sock_tag(sock_tag_entry);
+		pr_debug("%*d: %s,\n", indent_level*2, indent_level, str);
+		kfree(str);
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+void prdebug_proc_qtu_data_tree(int indent_level,
+				struct rb_root *proc_qtu_data_tree)
+{
+	char *str;
+	struct rb_node *node;
+	struct proc_qtu_data *proc_qtu_data_entry;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (RB_EMPTY_ROOT(proc_qtu_data_tree)) {
+		str = "proc_qtu_data_tree=rb_root{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "proc_qtu_data_tree=rb_root{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	for (node = rb_first(proc_qtu_data_tree);
+	     node;
+	     node = rb_next(node)) {
+		proc_qtu_data_entry = rb_entry(node,
+					       struct proc_qtu_data,
+					       node);
+		str = pp_proc_qtu_data(proc_qtu_data_entry);
+		pr_debug("%*d: %s,\n", indent_level*2, indent_level,
+			 str);
+		kfree(str);
+		indent_level++;
+		prdebug_sock_tag_list(indent_level,
+				      &proc_qtu_data_entry->sock_tag_list);
+		indent_level--;
+
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+void prdebug_tag_ref_tree(int indent_level, struct rb_root *tag_ref_tree)
+{
+	char *str;
+	struct rb_node *node;
+	struct tag_ref *tag_ref_entry;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (RB_EMPTY_ROOT(tag_ref_tree)) {
+		str = "tag_ref_tree{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "tag_ref_tree{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	for (node = rb_first(tag_ref_tree);
+	     node;
+	     node = rb_next(node)) {
+		tag_ref_entry = rb_entry(node,
+					 struct tag_ref,
+					 tn.node);
+		str = pp_tag_ref(tag_ref_entry);
+		pr_debug("%*d: %s,\n", indent_level*2, indent_level,
+			 str);
+		kfree(str);
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+void prdebug_uid_tag_data_tree(int indent_level,
+			       struct rb_root *uid_tag_data_tree)
+{
+	char *str;
+	struct rb_node *node;
+	struct uid_tag_data *uid_tag_data_entry;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (RB_EMPTY_ROOT(uid_tag_data_tree)) {
+		str = "uid_tag_data_tree=rb_root{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "uid_tag_data_tree=rb_root{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	for (node = rb_first(uid_tag_data_tree);
+	     node;
+	     node = rb_next(node)) {
+		uid_tag_data_entry = rb_entry(node, struct uid_tag_data,
+					      node);
+		str = pp_uid_tag_data(uid_tag_data_entry);
+		pr_debug("%*d: %s,\n", indent_level*2, indent_level, str);
+		kfree(str);
+		if (!RB_EMPTY_ROOT(&uid_tag_data_entry->tag_ref_tree)) {
+			indent_level++;
+			prdebug_tag_ref_tree(indent_level,
+					     &uid_tag_data_entry->tag_ref_tree);
+			indent_level--;
+		}
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+void prdebug_tag_stat_tree(int indent_level,
+				  struct rb_root *tag_stat_tree)
+{
+	char *str;
+	struct rb_node *node;
+	struct tag_stat *ts_entry;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (RB_EMPTY_ROOT(tag_stat_tree)) {
+		str = "tag_stat_tree{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "tag_stat_tree{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	for (node = rb_first(tag_stat_tree);
+	     node;
+	     node = rb_next(node)) {
+		ts_entry = rb_entry(node, struct tag_stat, tn.node);
+		str = pp_tag_stat(ts_entry);
+		pr_debug("%*d: %s\n", indent_level*2, indent_level,
+			 str);
+		kfree(str);
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+void prdebug_iface_stat_list(int indent_level,
+			     struct list_head *iface_stat_list)
+{
+	char *str;
+	struct iface_stat *iface_entry;
+
+	if (!unlikely(qtaguid_debug_mask & DDEBUG_MASK))
+		return;
+
+	if (list_empty(iface_stat_list)) {
+		str = "iface_stat_list=list_head{}";
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		return;
+	}
+
+	str = "iface_stat_list=list_head{";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+	indent_level++;
+	list_for_each_entry(iface_entry, iface_stat_list, list) {
+		str = pp_iface_stat(iface_entry);
+		pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+		kfree(str);
+
+		spin_lock_bh(&iface_entry->tag_stat_list_lock);
+		if (!RB_EMPTY_ROOT(&iface_entry->tag_stat_tree)) {
+			indent_level++;
+			prdebug_tag_stat_tree(indent_level,
+					      &iface_entry->tag_stat_tree);
+			indent_level--;
+		}
+		spin_unlock_bh(&iface_entry->tag_stat_list_lock);
+	}
+	indent_level--;
+	str = "}";
+	pr_debug("%*d: %s\n", indent_level*2, indent_level, str);
+}
+
+#endif  /* ifdef DDEBUG */
+/*------------------------------------------*/
+static const char * const netdev_event_strings[] = {
+	"netdev_unknown",
+	"NETDEV_UP",
+	"NETDEV_DOWN",
+	"NETDEV_REBOOT",
+	"NETDEV_CHANGE",
+	"NETDEV_REGISTER",
+	"NETDEV_UNREGISTER",
+	"NETDEV_CHANGEMTU",
+	"NETDEV_CHANGEADDR",
+	"NETDEV_GOING_DOWN",
+	"NETDEV_CHANGENAME",
+	"NETDEV_FEAT_CHANGE",
+	"NETDEV_BONDING_FAILOVER",
+	"NETDEV_PRE_UP",
+	"NETDEV_PRE_TYPE_CHANGE",
+	"NETDEV_POST_TYPE_CHANGE",
+	"NETDEV_POST_INIT",
+	"NETDEV_UNREGISTER_BATCH",
+	"NETDEV_RELEASE",
+	"NETDEV_NOTIFY_PEERS",
+	"NETDEV_JOIN",
+};
+
+const char *netdev_evt_str(int netdev_event)
+{
+	if (netdev_event < 0
+	    || netdev_event >= ARRAY_SIZE(netdev_event_strings))
+		return "bad event num";
+	return netdev_event_strings[netdev_event];
+}
diff --git a/net/netfilter/xt_qtaguid_print.h b/net/netfilter/xt_qtaguid_print.h
new file mode 100644
index 0000000..b63871a
--- /dev/null
+++ b/net/netfilter/xt_qtaguid_print.h
@@ -0,0 +1,120 @@
+/*
+ * Pretty printing Support for iptables xt_qtaguid module.
+ *
+ * (C) 2011 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __XT_QTAGUID_PRINT_H__
+#define __XT_QTAGUID_PRINT_H__
+
+#include "xt_qtaguid_internal.h"
+
+#ifdef DDEBUG
+
+char *pp_tag_t(tag_t *tag);
+char *pp_data_counters(struct data_counters *dc, bool showValues);
+char *pp_tag_node(struct tag_node *tn);
+char *pp_tag_ref(struct tag_ref *tr);
+char *pp_tag_stat(struct tag_stat *ts);
+char *pp_iface_stat(struct iface_stat *is);
+char *pp_sock_tag(struct sock_tag *st);
+char *pp_uid_tag_data(struct uid_tag_data *qtd);
+char *pp_proc_qtu_data(struct proc_qtu_data *pqd);
+
+/*------------------------------------------*/
+void prdebug_sock_tag_list(int indent_level,
+			   struct list_head *sock_tag_list);
+void prdebug_sock_tag_tree(int indent_level,
+			   struct rb_root *sock_tag_tree);
+void prdebug_proc_qtu_data_tree(int indent_level,
+				struct rb_root *proc_qtu_data_tree);
+void prdebug_tag_ref_tree(int indent_level, struct rb_root *tag_ref_tree);
+void prdebug_uid_tag_data_tree(int indent_level,
+			       struct rb_root *uid_tag_data_tree);
+void prdebug_tag_stat_tree(int indent_level,
+			   struct rb_root *tag_stat_tree);
+void prdebug_iface_stat_list(int indent_level,
+			     struct list_head *iface_stat_list);
+
+#else
+
+/*------------------------------------------*/
+static inline char *pp_tag_t(tag_t *tag)
+{
+	return NULL;
+}
+static inline char *pp_data_counters(struct data_counters *dc, bool showValues)
+{
+	return NULL;
+}
+static inline char *pp_tag_node(struct tag_node *tn)
+{
+	return NULL;
+}
+static inline char *pp_tag_ref(struct tag_ref *tr)
+{
+	return NULL;
+}
+static inline char *pp_tag_stat(struct tag_stat *ts)
+{
+	return NULL;
+}
+static inline char *pp_iface_stat(struct iface_stat *is)
+{
+	return NULL;
+}
+static inline char *pp_sock_tag(struct sock_tag *st)
+{
+	return NULL;
+}
+static inline char *pp_uid_tag_data(struct uid_tag_data *qtd)
+{
+	return NULL;
+}
+static inline char *pp_proc_qtu_data(struct proc_qtu_data *pqd)
+{
+	return NULL;
+}
+
+/*------------------------------------------*/
+static inline
+void prdebug_sock_tag_list(int indent_level,
+			   struct list_head *sock_tag_list)
+{
+}
+static inline
+void prdebug_sock_tag_tree(int indent_level,
+			   struct rb_root *sock_tag_tree)
+{
+}
+static inline
+void prdebug_proc_qtu_data_tree(int indent_level,
+				struct rb_root *proc_qtu_data_tree)
+{
+}
+static inline
+void prdebug_tag_ref_tree(int indent_level, struct rb_root *tag_ref_tree)
+{
+}
+static inline
+void prdebug_uid_tag_data_tree(int indent_level,
+			       struct rb_root *uid_tag_data_tree)
+{
+}
+static inline
+void prdebug_tag_stat_tree(int indent_level,
+			   struct rb_root *tag_stat_tree)
+{
+}
+static inline
+void prdebug_iface_stat_list(int indent_level,
+			     struct list_head *iface_stat_list)
+{
+}
+#endif
+/*------------------------------------------*/
+const char *netdev_evt_str(int netdev_event);
+#endif  /* ifndef __XT_QTAGUID_PRINT_H__ */
