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Date:	Sat, 22 Sep 2012 23:18:24 +0200
From:	richard -rw- weinberger <richard.weinberger@...il.com>
To:	John Stultz <john.stultz@...aro.org>
Cc:	LKML <linux-kernel@...r.kernel.org>, JP Abgrall <jpa@...gle.com>,
	netdev@...r.kernel.org, Ashish Sharma <ashishsharma@...gle.com>,
	Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@...el.com>
Subject: Re: [PATCH 2/7][RFC] netfilter: add xt_qtaguid matching module

Just a few comments, please see below.
In general I'd send this module also to netfilter-devel@... and get
rid of most debugging stuff.

On Sat, Sep 22, 2012 at 4:10 AM, John Stultz <john.stultz@...aro.org> wrote:
> Put procfs dirs in /proc/net/xt_qtaguid/
>   ctrl
>   stats
>   iface_stat/<iface>/...
> The uid stats are obtainable in ./stats.

Do we really want new files in /proc?

> +static const char *module_procdirname = "xt_qtaguid";

Why not char[]?

> +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"

We have this string already in module_procdirname.

> +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();

WARN_ONCE(), please.
Otherwise an attacker may trigger the BUG() remotely in case of an
implementation error...

> +       }
> +
> +       /* 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();

Same here.

> +       }
> +
> +       /* 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();

Same here.

> +       }
> +
> +       /* 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();

Same here.

> +       }
> +
> +       /* 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;
> +       }

Can ifname really become 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 :(
> +        */

Is it fixed now?

> +       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@...gle.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@...l{}");
> +       else
> +               res = kasprintf(GFP_ATOMIC,
> +                               "tag_t@...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@...l{}");
> +       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@......}", 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@...l{}");
> +               _bug_on_err_or_null(res);
> +               return res;
> +       }
> +       tag_str = pp_tag_t(&tn->tag);
> +       res = kasprintf(GFP_ATOMIC,
> +                       "tag_node@...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@...l{}");
> +               _bug_on_err_or_null(res);
> +               return res;
> +       }
> +       tn_str = pp_tag_node(&tr->tn);
> +       res = kasprintf(GFP_ATOMIC,
> +                       "tag_ref@...%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@...l{}");
> +               _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@...%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@...l{}");
> +       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@...l{}");
> +               _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@...l{}");
> +       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@...l{}");
> +               _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__ */
> --
> 1.7.9.5

-- 
Thanks,
//richard
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