batman-adv: allow multiple entries in tt_global_entries

as backbone gateways will all independently announce the same clients,
also the tt global table must be able to hold multiple originators per
client entry.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

2 files changed, 311 insertions, 93 deletions

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 5f8c540b9f17..9648b0dc57ef 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -32,10 +32,8 @@
 
 static void send_roam_adv(struct bat_priv *bat_priv, uint8_t *client,
                           struct orig_node *orig_node);
-static void _tt_global_del(struct bat_priv *bat_priv,
-                           struct tt_global_entry *tt_global_entry,
-                           const char *message);
 static void tt_purge(struct work_struct *work);
+static void tt_global_del_orig_list(struct tt_global_entry *tt_global_entry);
 
 /* returns 1 if they are the same mac addr */
 static int compare_tt(const struct hlist_node *node, const void *data2)
@@ -125,17 +123,31 @@ static void tt_global_entry_free_rcu(struct rcu_head *rcu)
         tt_global_entry = container_of(tt_common_entry, struct tt_global_entry,
                                        common);
 
-        if (tt_global_entry->orig_node)
-                orig_node_free_ref(tt_global_entry->orig_node);
-
         kfree(tt_global_entry);
 }
 
 static void tt_global_entry_free_ref(struct tt_global_entry *tt_global_entry)
 {
-        if (atomic_dec_and_test(&tt_global_entry->common.refcount))
+        if (atomic_dec_and_test(&tt_global_entry->common.refcount)) {
+                tt_global_del_orig_list(tt_global_entry);
                 call_rcu(&tt_global_entry->common.rcu,
                          tt_global_entry_free_rcu);
+        }
+}
+
+static void tt_orig_list_entry_free_rcu(struct rcu_head *rcu)
+{
+        struct tt_orig_list_entry *orig_entry;
+
+        orig_entry = container_of(rcu, struct tt_orig_list_entry, rcu);
+        atomic_dec(&orig_entry->orig_node->tt_size);
+        orig_node_free_ref(orig_entry->orig_node);
+        kfree(orig_entry);
+}
+
+static void tt_orig_list_entry_free_ref(struct tt_orig_list_entry *orig_entry)
+{
+        call_rcu(&orig_entry->rcu, tt_orig_list_entry_free_rcu);
 }
 
 static void tt_local_event(struct bat_priv *bat_priv, const uint8_t *addr,
@@ -184,6 +196,9 @@ void tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
         struct bat_priv *bat_priv = netdev_priv(soft_iface);
         struct tt_local_entry *tt_local_entry = NULL;
         struct tt_global_entry *tt_global_entry = NULL;
+        struct hlist_head *head;
+        struct hlist_node *node;
+        struct tt_orig_list_entry *orig_entry;
         int hash_added;
 
         tt_local_entry = tt_local_hash_find(bat_priv, addr);
@@ -234,14 +249,21 @@ void tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
 
         /* Check whether it is a roaming! */
         if (tt_global_entry) {
-                /* This node is probably going to update its tt table */
-                tt_global_entry->orig_node->tt_poss_change = true;
-                /* The global entry has to be marked as ROAMING and has to be
-                 * kept for consistency purpose */
+                /* These node are probably going to update their tt table */
+                head = &tt_global_entry->orig_list;
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(orig_entry, node, head, list) {
+                        orig_entry->orig_node->tt_poss_change = true;
+
+                        send_roam_adv(bat_priv, tt_global_entry->common.addr,
+                                      orig_entry->orig_node);
+                }
+                rcu_read_unlock();
+                /* The global entry has to be marked as ROAMING and
+                 * has to be kept for consistency purpose
+                 */
                 tt_global_entry->common.flags |= TT_CLIENT_ROAM;
                 tt_global_entry->roam_at = jiffies;
-                send_roam_adv(bat_priv, tt_global_entry->common.addr,
-                              tt_global_entry->orig_node);
         }
 out:
         if (tt_local_entry)
@@ -492,33 +514,76 @@ static void tt_changes_list_free(struct bat_priv *bat_priv)
         spin_unlock_bh(&bat_priv->tt_changes_list_lock);
 }
 
+/* find out if an orig_node is already in the list of a tt_global_entry.
+ * returns 1 if found, 0 otherwise
+ */
+static bool tt_global_entry_has_orig(const struct tt_global_entry *entry,
+                                     const struct orig_node *orig_node)
+{
+        struct tt_orig_list_entry *tmp_orig_entry;
+        const struct hlist_head *head;
+        struct hlist_node *node;
+        bool found = false;
+
+        rcu_read_lock();
+        head = &entry->orig_list;
+        hlist_for_each_entry_rcu(tmp_orig_entry, node, head, list) {
+                if (tmp_orig_entry->orig_node == orig_node) {
+                        found = true;
+                        break;
+                }
+        }
+        rcu_read_unlock();
+        return found;
+}
+
+static void tt_global_add_orig_entry(struct tt_global_entry *tt_global_entry,
+                                     struct orig_node *orig_node,
+                                     int ttvn)
+{
+        struct tt_orig_list_entry *orig_entry;
+
+        orig_entry = kzalloc(sizeof(*orig_entry), GFP_ATOMIC);
+        if (!orig_entry)
+                return;
+
+        INIT_HLIST_NODE(&orig_entry->list);
+        atomic_inc(&orig_node->refcount);
+        atomic_inc(&orig_node->tt_size);
+        orig_entry->orig_node = orig_node;
+        orig_entry->ttvn = ttvn;
+
+        spin_lock_bh(&tt_global_entry->list_lock);
+        hlist_add_head_rcu(&orig_entry->list,
+                           &tt_global_entry->orig_list);
+        spin_unlock_bh(&tt_global_entry->list_lock);
+}
+
 /* caller must hold orig_node refcount */
 int tt_global_add(struct bat_priv *bat_priv, struct orig_node *orig_node,
                   const unsigned char *tt_addr, uint8_t ttvn, bool roaming,
                   bool wifi)
 {
-        struct tt_global_entry *tt_global_entry;
-        struct orig_node *orig_node_tmp;
+        struct tt_global_entry *tt_global_entry = NULL;
         int ret = 0;
         int hash_added;
 
         tt_global_entry = tt_global_hash_find(bat_priv, tt_addr);
 
         if (!tt_global_entry) {
-                tt_global_entry =
-                        kmalloc(sizeof(*tt_global_entry),
-                                GFP_ATOMIC);
+                tt_global_entry = kzalloc(sizeof(*tt_global_entry),
+                                          GFP_ATOMIC);
                 if (!tt_global_entry)
                         goto out;
 
                 memcpy(tt_global_entry->common.addr, tt_addr, ETH_ALEN);
+
                 tt_global_entry->common.flags = NO_FLAGS;
-                atomic_set(&tt_global_entry->common.refcount, 2);
-                /* Assign the new orig_node */
-                atomic_inc(&orig_node->refcount);
-                tt_global_entry->orig_node = orig_node;
-                tt_global_entry->ttvn = ttvn;
                 tt_global_entry->roam_at = 0;
+                atomic_set(&tt_global_entry->common.refcount, 2);
+
+                INIT_HLIST_HEAD(&tt_global_entry->orig_list);
+                spin_lock_init(&tt_global_entry->list_lock);
 
                 hash_added = hash_add(bat_priv->tt_global_hash, compare_tt,
                                  choose_orig, &tt_global_entry->common,
@@ -529,19 +594,27 @@ int tt_global_add(struct bat_priv *bat_priv, struct orig_node *orig_node,
                         tt_global_entry_free_ref(tt_global_entry);
                         goto out_remove;
                 }
-                atomic_inc(&orig_node->tt_size);
+
+                tt_global_add_orig_entry(tt_global_entry, orig_node, ttvn);
         } else {
-                if (tt_global_entry->orig_node != orig_node) {
-                        atomic_dec(&tt_global_entry->orig_node->tt_size);
-                        orig_node_tmp = tt_global_entry->orig_node;
-                        atomic_inc(&orig_node->refcount);
-                        tt_global_entry->orig_node = orig_node;
-                        orig_node_free_ref(orig_node_tmp);
-                        atomic_inc(&orig_node->tt_size);
+                /* there is already a global entry, use this one. */
+
+                /* If there is the TT_CLIENT_ROAM flag set, there is only one
+                 * originator left in the list and we previously received a
+                 * delete + roaming change for this originator.
+                 *
+                 * We should first delete the old originator before adding the
+                 * new one.
+                 */
+                if (tt_global_entry->common.flags & TT_CLIENT_ROAM) {
+                        tt_global_del_orig_list(tt_global_entry);
+                        tt_global_entry->common.flags &= ~TT_CLIENT_ROAM;
+                        tt_global_entry->roam_at = 0;
                 }
-                tt_global_entry->common.flags = NO_FLAGS;
-                tt_global_entry->ttvn = ttvn;
-                tt_global_entry->roam_at = 0;
+
+                if (!tt_global_entry_has_orig(tt_global_entry, orig_node))
+                        tt_global_add_orig_entry(tt_global_entry, orig_node,
+                                                 ttvn);
         }
 
         if (wifi)
@@ -562,6 +635,34 @@ out:
         return ret;
 }
 
+/* print all orig nodes who announce the address for this global entry.
+ * it is assumed that the caller holds rcu_read_lock();
+ */
+static void tt_global_print_entry(struct tt_global_entry *tt_global_entry,
+                                  struct seq_file *seq)
+{
+        struct hlist_head *head;
+        struct hlist_node *node;
+        struct tt_orig_list_entry *orig_entry;
+        struct tt_common_entry *tt_common_entry;
+        uint16_t flags;
+        uint8_t last_ttvn;
+
+        tt_common_entry = &tt_global_entry->common;
+
+        head = &tt_global_entry->orig_list;
+
+        hlist_for_each_entry_rcu(orig_entry, node, head, list) {
+                flags = tt_common_entry->flags;
+                last_ttvn = atomic_read(&orig_entry->orig_node->last_ttvn);
+                seq_printf(seq, " * %pM  (%3u) via %pM     (%3u)   [%c%c]\n",
+                           tt_global_entry->common.addr, orig_entry->ttvn,
+                           orig_entry->orig_node->orig, last_ttvn,
+                           (flags & TT_CLIENT_ROAM ? 'R' : '.'),
+                           (flags & TT_CLIENT_WIFI ? 'W' : '.'));
+        }
+}
+
 int tt_global_seq_print_text(struct seq_file *seq, void *offset)
 {
         struct net_device *net_dev = (struct net_device *)seq->private;
@@ -605,18 +706,7 @@ int tt_global_seq_print_text(struct seq_file *seq, void *offset)
                         tt_global_entry = container_of(tt_common_entry,
                                                        struct tt_global_entry,
                                                        common);
-                        seq_printf(seq,
-                                   " * %pM  (%3u) via %pM     (%3u)   [%c%c]\n",
-                                   tt_global_entry->common.addr,
-                                   tt_global_entry->ttvn,
-                                   tt_global_entry->orig_node->orig,
-                                   (uint8_t) atomic_read(
-                                                &tt_global_entry->orig_node->
-                                                last_ttvn),
-                                   (tt_global_entry->common.flags &
-                                    TT_CLIENT_ROAM ? 'R' : '.'),
-                                   (tt_global_entry->common.flags &
-                                    TT_CLIENT_WIFI ? 'W' : '.'));
+                        tt_global_print_entry(tt_global_entry, seq);
                 }
                 rcu_read_unlock();
         }
@@ -626,27 +716,103 @@ out:
         return ret;
 }
 
-static void _tt_global_del(struct bat_priv *bat_priv,
-                           struct tt_global_entry *tt_global_entry,
-                           const char *message)
+/* deletes the orig list of a tt_global_entry */
+static void tt_global_del_orig_list(struct tt_global_entry *tt_global_entry)
 {
-        if (!tt_global_entry)
-                goto out;
+        struct hlist_head *head;
+        struct hlist_node *node, *safe;
+        struct tt_orig_list_entry *orig_entry;
 
-        bat_dbg(DBG_TT, bat_priv,
-                "Deleting global tt entry %pM (via %pM): %s\n",
-                tt_global_entry->common.addr, tt_global_entry->orig_node->orig,
-                message);
+        spin_lock_bh(&tt_global_entry->list_lock);
+        head = &tt_global_entry->orig_list;
+        hlist_for_each_entry_safe(orig_entry, node, safe, head, list) {
+                hlist_del_rcu(node);
+                tt_orig_list_entry_free_ref(orig_entry);
+        }
+        spin_unlock_bh(&tt_global_entry->list_lock);
 
-        atomic_dec(&tt_global_entry->orig_node->tt_size);
+}
+
+static void tt_global_del_orig_entry(struct bat_priv *bat_priv,
+                                     struct tt_global_entry *tt_global_entry,
+                                     struct orig_node *orig_node,
+                                     const char *message)
+{
+        struct hlist_head *head;
+        struct hlist_node *node, *safe;
+        struct tt_orig_list_entry *orig_entry;
+
+        spin_lock_bh(&tt_global_entry->list_lock);
+        head = &tt_global_entry->orig_list;
+        hlist_for_each_entry_safe(orig_entry, node, safe, head, list) {
+                if (orig_entry->orig_node == orig_node) {
+                        bat_dbg(DBG_TT, bat_priv,
+                                "Deleting %pM from global tt entry %pM: %s\n",
+                                orig_node->orig, tt_global_entry->common.addr,
+                                message);
+                        hlist_del_rcu(node);
+                        tt_orig_list_entry_free_ref(orig_entry);
+                }
+        }
+        spin_unlock_bh(&tt_global_entry->list_lock);
+}
+
+static void tt_global_del_struct(struct bat_priv *bat_priv,
+                                 struct tt_global_entry *tt_global_entry,
+                                 const char *message)
+{
+        bat_dbg(DBG_TT, bat_priv,
+                "Deleting global tt entry %pM: %s\n",
+                tt_global_entry->common.addr, message);
 
         hash_remove(bat_priv->tt_global_hash, compare_tt, choose_orig,
                     tt_global_entry->common.addr);
-out:
-        if (tt_global_entry)
-                tt_global_entry_free_ref(tt_global_entry);
+        tt_global_entry_free_ref(tt_global_entry);
+
 }
 
+/* If the client is to be deleted, we check if it is the last origantor entry
+ * within tt_global entry. If yes, we set the TT_CLIENT_ROAM flag and the timer,
+ * otherwise we simply remove the originator scheduled for deletion.
+ */
+static void tt_global_del_roaming(struct bat_priv *bat_priv,
+                                  struct tt_global_entry *tt_global_entry,
+                                  struct orig_node *orig_node,
+                                  const char *message)
+{
+        bool last_entry = true;
+        struct hlist_head *head;
+        struct hlist_node *node;
+        struct tt_orig_list_entry *orig_entry;
+
+        /* no local entry exists, case 1:
+         * Check if this is the last one or if other entries exist.
+         */
+
+        rcu_read_lock();
+        head = &tt_global_entry->orig_list;
+        hlist_for_each_entry_rcu(orig_entry, node, head, list) {
+                if (orig_entry->orig_node != orig_node) {
+                        last_entry = false;
+                        break;
+                }
+        }
+        rcu_read_unlock();
+
+        if (last_entry) {
+                /* its the last one, mark for roaming. */
+                tt_global_entry->common.flags |= TT_CLIENT_ROAM;
+                tt_global_entry->roam_at = jiffies;
+        } else
+                /* there is another entry, we can simply delete this
+                 * one and can still use the other one.
+                 */
+                tt_global_del_orig_entry(bat_priv, tt_global_entry,
+                                         orig_node, message);
+}
+
+
+
 static void tt_global_del(struct bat_priv *bat_priv,
                           struct orig_node *orig_node,
                           const unsigned char *addr,
@@ -656,30 +822,44 @@ static void tt_global_del(struct bat_priv *bat_priv,
         struct tt_local_entry *tt_local_entry = NULL;
 
         tt_global_entry = tt_global_hash_find(bat_priv, addr);
-        if (!tt_global_entry || tt_global_entry->orig_node != orig_node)
+        if (!tt_global_entry)
                 goto out;
 
-        if (!roaming)
-                goto out_del;
+        if (!roaming) {
+                tt_global_del_orig_entry(bat_priv, tt_global_entry, orig_node,
+                                         message);
+
+                if (hlist_empty(&tt_global_entry->orig_list))
+                        tt_global_del_struct(bat_priv, tt_global_entry,
+                                             message);
+
+                goto out;
+        }
 
         /* if we are deleting a global entry due to a roam
          * event, there are two possibilities:
-         * 1) the client roamed from node A to node B => we mark
+         * 1) the client roamed from node A to node B => if there
+         *    is only one originator left for this client, we mark
          *    it with TT_CLIENT_ROAM, we start a timer and we
          *    wait for node B to claim it. In case of timeout
          *    the entry is purged.
+         *
+         *    If there are other originators left, we directly delete
+         *    the originator.
          * 2) the client roamed to us => we can directly delete
          *    the global entry, since it is useless now. */
+
         tt_local_entry = tt_local_hash_find(bat_priv,
                                             tt_global_entry->common.addr);
-        if (!tt_local_entry) {
-                tt_global_entry->common.flags |= TT_CLIENT_ROAM;
-                tt_global_entry->roam_at = jiffies;
-                goto out;
-        }
+        if (tt_local_entry) {
+                /* local entry exists, case 2: client roamed to us. */
+                tt_global_del_orig_list(tt_global_entry);
+                tt_global_del_struct(bat_priv, tt_global_entry, message);
+        } else
+                /* no local entry exists, case 1: check for roaming */
+                tt_global_del_roaming(bat_priv, tt_global_entry, orig_node,
+                                      message);
 
-out_del:
-        _tt_global_del(bat_priv, tt_global_entry, message);
 
 out:
         if (tt_global_entry)
@@ -712,11 +892,14 @@ void tt_global_del_orig(struct bat_priv *bat_priv,
                         tt_global_entry = container_of(tt_common_entry,
                                                        struct tt_global_entry,
                                                        common);
-                        if (tt_global_entry->orig_node == orig_node) {
+
+                        tt_global_del_orig_entry(bat_priv, tt_global_entry,
+                                                 orig_node, message);
+
+                        if (hlist_empty(&tt_global_entry->orig_list)) {
                                 bat_dbg(DBG_TT, bat_priv,
-                                        "Deleting global tt entry %pM (via %pM): %s\n",
+                                        "Deleting global tt entry %pM: %s\n",
                                         tt_global_entry->common.addr,
-                                        tt_global_entry->orig_node->orig,
                                         message);
                                 hlist_del_rcu(node);
                                 tt_global_entry_free_ref(tt_global_entry);
@@ -757,7 +940,7 @@ static void tt_global_roam_purge(struct bat_priv *bat_priv)
                         bat_dbg(DBG_TT, bat_priv,
                                 "Deleting global tt entry (%pM): Roaming timeout\n",
                                 tt_global_entry->common.addr);
-                        atomic_dec(&tt_global_entry->orig_node->tt_size);
+
                         hlist_del_rcu(node);
                         tt_global_entry_free_ref(tt_global_entry);
                 }
@@ -820,6 +1003,11 @@ struct orig_node *transtable_search(struct bat_priv *bat_priv,
         struct tt_local_entry *tt_local_entry = NULL;
         struct tt_global_entry *tt_global_entry = NULL;
         struct orig_node *orig_node = NULL;
+        struct neigh_node *router = NULL;
+        struct hlist_head *head;
+        struct hlist_node *node;
+        struct tt_orig_list_entry *orig_entry;
+        int best_tq;
 
         if (src && atomic_read(&bat_priv->ap_isolation)) {
                 tt_local_entry = tt_local_hash_find(bat_priv, src);
@@ -836,11 +1024,25 @@ struct orig_node *transtable_search(struct bat_priv *bat_priv,
         if (tt_local_entry && _is_ap_isolated(tt_local_entry, tt_global_entry))
                 goto out;
 
-        if (!atomic_inc_not_zero(&tt_global_entry->orig_node->refcount))
-                goto out;
+        best_tq = 0;
 
-        orig_node = tt_global_entry->orig_node;
+        rcu_read_lock();
+        head = &tt_global_entry->orig_list;
+        hlist_for_each_entry_rcu(orig_entry, node, head, list) {
+                router = orig_node_get_router(orig_entry->orig_node);
+                if (!router)
+                        continue;
 
+                if (router->tq_avg > best_tq) {
+                        orig_node = orig_entry->orig_node;
+                        best_tq = router->tq_avg;
+                }
+                neigh_node_free_ref(router);
+        }
+        /* found anything? */
+        if (orig_node && !atomic_inc_not_zero(&orig_node->refcount))
+                orig_node = NULL;
+        rcu_read_unlock();
 out:
         if (tt_global_entry)
                 tt_global_entry_free_ref(tt_global_entry);
@@ -872,20 +1074,26 @@ static uint16_t tt_global_crc(struct bat_priv *bat_priv,
                         tt_global_entry = container_of(tt_common_entry,
                                                        struct tt_global_entry,
                                                        common);
-                        if (compare_eth(tt_global_entry->orig_node,
-                                        orig_node)) {
-                                /* Roaming clients are in the global table for
-                                 * consistency only. They don't have to be
-                                 * taken into account while computing the
-                                 * global crc */
-                                if (tt_common_entry->flags & TT_CLIENT_ROAM)
-                                        continue;
-                                total_one = 0;
-                                for (j = 0; j < ETH_ALEN; j++)
-                                        total_one = crc16_byte(total_one,
-                                                tt_common_entry->addr[j]);
-                                total ^= total_one;
-                        }
+                        /* Roaming clients are in the global table for
+                         * consistency only. They don't have to be
+                         * taken into account while computing the
+                         * global crc
+                         */
+                        if (tt_global_entry->common.flags & TT_CLIENT_ROAM)
+                                continue;
+
+                        /* find out if this global entry is announced by this
+                         * originator
+                         */
+                        if (!tt_global_entry_has_orig(tt_global_entry,
+                                                      orig_node))
+                                continue;
+
+                        total_one = 0;
+                        for (j = 0; j < ETH_ALEN; j++)
+                                total_one = crc16_byte(total_one,
+                                        tt_global_entry->common.addr[j]);
+                        total ^= total_one;
                 }
                 rcu_read_unlock();
         }
@@ -1026,7 +1234,7 @@ static int tt_global_valid_entry(const void *entry_ptr, const void *data_ptr)
         tt_global_entry = container_of(tt_common_entry, struct tt_global_entry,
                                        common);
 
-        return (tt_global_entry->orig_node == orig_node);
+        return tt_global_entry_has_orig(tt_global_entry, orig_node);
 }
 
 static struct sk_buff *tt_response_fill_table(uint16_t tt_len, uint8_t ttvn,
@@ -1802,6 +2010,8 @@ void tt_commit_changes(struct bat_priv *bat_priv)
 
         /* Increment the TTVN only once per OGM interval */
         atomic_inc(&bat_priv->ttvn);
+        bat_dbg(DBG_TT, bat_priv, "Local changes committed, updating to ttvn %u\n",
+                (uint8_t)atomic_read(&bat_priv->ttvn));
         bat_priv->tt_poss_change = false;
 }
 
@@ -1879,6 +2089,7 @@ void tt_update_orig(struct bat_priv *bat_priv, struct orig_node *orig_node,
         } else {
                 /* if we missed more than one change or our tables are not
                  * in sync anymore -> request fresh tt data */
+
                 if (!orig_node->tt_initialised || ttvn != orig_ttvn ||
                     orig_node->tt_crc != tt_crc) {
 request_table:
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 089dd44a29b1..35cd831508a9 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -241,9 +241,16 @@ struct tt_local_entry {
 
 struct tt_global_entry {
         struct tt_common_entry common;
+        struct hlist_head orig_list;
+        spinlock_t list_lock;   /* protects the list */
+        unsigned long roam_at; /* time at which TT_GLOBAL_ROAM was set */
+};
+
+struct tt_orig_list_entry {
         struct orig_node *orig_node;
         uint8_t ttvn;
-        unsigned long roam_at; /* time at which TT_GLOBAL_ROAM was set */
+        struct rcu_head rcu;
+        struct hlist_node list;
 };
 
 struct backbone_gw {