Commit 068ee6e2 authored by Antonio Quartulli's avatar Antonio Quartulli
Browse files

batman-adv: roaming handling mechanism redesign 



This patch allows clients to roam multiple times within the same
originator-interval.

To enable this new feature two key aspects that have been introduced:
1) packets are always directed to the node that was originally
serving the roamed client which will then re-route the data
to the correct destination at any point in time;
2) the client flags handling mechanism has been properly modified
in order to allow multiple roamings withinin the same orig-int.
Therefore flags are now set properly even in this scenario.

Signed-off-by: default avatarAntonio Quartulli <ordex@autistici.org>
parent be73b488

net/batman-adv/translation-table.c

+118 −39
Original line number Diff line number Diff line
@@ -238,6 +238,20 @@ static int batadv_tt_local_init(struct batadv_priv *bat_priv) 
	return 0;

}



static void batadv_tt_global_free(struct batadv_priv *bat_priv,

				  struct batadv_tt_global_entry *tt_global,

				  const char *message)

{

	batadv_dbg(BATADV_DBG_TT, bat_priv,

		   "Deleting global tt entry %pM: %s\n",

		   tt_global->common.addr, message);



	batadv_hash_remove(bat_priv->tt.global_hash, batadv_compare_tt,

			   batadv_choose_orig, tt_global->common.addr);

	batadv_tt_global_entry_free_ref(tt_global);



}



void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,

			 int ifindex)

{
@@ -248,14 +262,38 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, 
	struct hlist_node *node;

	struct batadv_tt_orig_list_entry *orig_entry;

	int hash_added;

	bool roamed_back = false;



	tt_local = batadv_tt_local_hash_find(bat_priv, addr);

	tt_global = batadv_tt_global_hash_find(bat_priv, addr);



	if (tt_local) {

		tt_local->last_seen = jiffies;

		/* possibly unset the BATADV_TT_CLIENT_PENDING flag */

		if (tt_local->common.flags & BATADV_TT_CLIENT_PENDING) {

			batadv_dbg(BATADV_DBG_TT, bat_priv,

				   "Re-adding pending client %pM\n", addr);

			/* whatever the reason why the PENDING flag was set,

			 * this is a client which was enqueued to be removed in

			 * this orig_interval. Since it popped up again, the

			 * flag can be reset like it was never enqueued

			 */

			tt_local->common.flags &= ~BATADV_TT_CLIENT_PENDING;

		goto out;

			goto add_event;

		}



		if (tt_local->common.flags & BATADV_TT_CLIENT_ROAM) {

			batadv_dbg(BATADV_DBG_TT, bat_priv,

				   "Roaming client %pM came back to its original location\n",

				   addr);

			/* the ROAM flag is set because this client roamed away

			 * and the node got a roaming_advertisement message. Now

			 * that the client popped up again at its original

			 * location such flag can be unset

			 */

			tt_local->common.flags &= ~BATADV_TT_CLIENT_ROAM;

			roamed_back = true;

		}

		goto check_roaming;

	}



	tt_local = kmalloc(sizeof(*tt_local), GFP_ATOMIC);
@@ -294,13 +332,14 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, 
		goto out;

	}



add_event:

	batadv_tt_local_event(bat_priv, addr, tt_local->common.flags);



	/* remove address from global hash if present */

	tt_global = batadv_tt_global_hash_find(bat_priv, addr);



	/* Check whether it is a roaming! */

	if (tt_global) {

check_roaming:

	/* Check whether it is a roaming, but don't do anything if the roaming

	 * process has already been handled

	 */

	if (tt_global && !(tt_global->common.flags & BATADV_TT_CLIENT_ROAM)) {

		/* These node are probably going to update their tt table */

		head = &tt_global->orig_list;

		rcu_read_lock();
@@ -309,12 +348,19 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, 
					     orig_entry->orig_node);

		}

		rcu_read_unlock();

		if (roamed_back) {

			batadv_tt_global_free(bat_priv, tt_global,

					      "Roaming canceled");

			tt_global = NULL;

		} else {

			/* The global entry has to be marked as ROAMING and

			 * has to be kept for consistency purpose

			 */

			tt_global->common.flags |= BATADV_TT_CLIENT_ROAM;

			tt_global->roam_at = jiffies;

		}

	}



out:

	if (tt_local)

		batadv_tt_local_entry_free_ref(tt_local);
@@ -508,13 +554,28 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, 
	curr_flags = tt_local_entry->common.flags;



	flags = BATADV_TT_CLIENT_DEL;

	/* if this global entry addition is due to a roaming, the node has to

	 * mark the local entry as "roamed" in order to correctly reroute

	 * packets later

	 */

	if (roaming) {

		flags |= BATADV_TT_CLIENT_ROAM;

		/* mark the local client as ROAMed */

		tt_local_entry->common.flags |= BATADV_TT_CLIENT_ROAM;

	}



	batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags, message);

	if (!(tt_local_entry->common.flags & BATADV_TT_CLIENT_NEW)) {

		batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags,

					    message);

		goto out;

	}

	/* if this client has been added right now, it is possible to

	 * immediately purge it

	 */

	batadv_tt_local_event(bat_priv, tt_local_entry->common.addr,

			      curr_flags | BATADV_TT_CLIENT_DEL);

	hlist_del_rcu(&tt_local_entry->common.hash_entry);

	batadv_tt_local_entry_free_ref(tt_local_entry);



out:

	if (tt_local_entry)
@@ -724,12 +785,22 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv, 
			 uint8_t ttvn)

{

	struct batadv_tt_global_entry *tt_global_entry = NULL;

	struct batadv_tt_local_entry *tt_local_entry = NULL;

	int ret = 0;

	int hash_added;

	struct batadv_tt_common_entry *common;

	uint16_t local_flags;



	tt_global_entry = batadv_tt_global_hash_find(bat_priv, tt_addr);

	tt_local_entry = batadv_tt_local_hash_find(bat_priv, tt_addr);



	/* if the node already has a local client for this entry, it has to wait

	 * for a roaming advertisement instead of manually messing up the global

	 * table

	 */

	if ((flags & BATADV_TT_CLIENT_TEMP) && tt_local_entry &&

	    !(tt_local_entry->common.flags & BATADV_TT_CLIENT_NEW))

		goto out;



	if (!tt_global_entry) {

		tt_global_entry = kzalloc(sizeof(*tt_global_entry), GFP_ATOMIC);
@@ -764,19 +835,31 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv, 
			goto out_remove;

		}

	} else {

		common = &tt_global_entry->common;

		/* If there is already a global entry, we can use this one for

		 * our processing.

		 * But if we are trying to add a temporary client we can exit

		 * directly because the temporary information should never

		 * override any already known client state (whatever it is)

		 * But if we are trying to add a temporary client then here are

		 * two options at this point:

		 * 1) the global client is not a temporary client: the global

		 *    client has to be left as it is, temporary information

		 *    should never override any already known client state

		 * 2) the global client is a temporary client: purge the

		 *    originator list and add the new one orig_entry

		 */

		if (flags & BATADV_TT_CLIENT_TEMP)

		if (flags & BATADV_TT_CLIENT_TEMP) {

			if (!(common->flags & BATADV_TT_CLIENT_TEMP))

				goto out;

			if (batadv_tt_global_entry_has_orig(tt_global_entry,

							    orig_node))

				goto out_remove;

			batadv_tt_global_del_orig_list(tt_global_entry);

			goto add_orig_entry;

		}



		/* if the client was temporary added before receiving the first

		 * OGM announcing it, we have to clear the TEMP flag

		 */

		tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_TEMP;

		common->flags &= ~BATADV_TT_CLIENT_TEMP;



		/* If there is the BATADV_TT_CLIENT_ROAM flag set, there is only

		 * one originator left in the list and we previously received a
@@ -785,18 +868,19 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv, 
		 * We should first delete the old originator before adding the

		 * new one.

		 */

		if (tt_global_entry->common.flags & BATADV_TT_CLIENT_ROAM) {

		if (common->flags & BATADV_TT_CLIENT_ROAM) {

			batadv_tt_global_del_orig_list(tt_global_entry);

			tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_ROAM;

			common->flags &= ~BATADV_TT_CLIENT_ROAM;

			tt_global_entry->roam_at = 0;

		}

	}

add_orig_entry:

	/* add the new orig_entry (if needed) or update it */

	batadv_tt_global_orig_entry_add(tt_global_entry, orig_node, ttvn);



	batadv_dbg(BATADV_DBG_TT, bat_priv,

		   "Creating new global tt entry: %pM (via %pM)\n",

		   tt_global_entry->common.addr, orig_node->orig);

		   common->addr, orig_node->orig);

	ret = 1;



out_remove:
@@ -804,12 +888,20 @@ out_remove: 
	/* remove address from local hash if present */

	local_flags = batadv_tt_local_remove(bat_priv, tt_addr,

					     "global tt received",

					     flags & BATADV_TT_CLIENT_ROAM);

					     !!(flags & BATADV_TT_CLIENT_ROAM));

	tt_global_entry->common.flags |= local_flags & BATADV_TT_CLIENT_WIFI;



	if (!(flags & BATADV_TT_CLIENT_ROAM))

		/* this is a normal global add. Therefore the client is not in a

		 * roaming state anymore.

		 */

		tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_ROAM;



out:

	if (tt_global_entry)

		batadv_tt_global_entry_free_ref(tt_global_entry);

	if (tt_local_entry)

		batadv_tt_local_entry_free_ref(tt_local_entry);

	return ret;

}
@@ -927,20 +1019,6 @@ batadv_tt_global_del_orig_entry(struct batadv_priv *bat_priv, 
	spin_unlock_bh(&tt_global_entry->list_lock);

}



static void batadv_tt_global_free(struct batadv_priv *bat_priv,

				  struct batadv_tt_global_entry *tt_global,

				  const char *message)

{

	batadv_dbg(BATADV_DBG_TT, bat_priv,

		   "Deleting global tt entry %pM: %s\n",

		   tt_global->common.addr, message);



	batadv_hash_remove(bat_priv->tt.global_hash, batadv_compare_tt,

			   batadv_choose_orig, tt_global->common.addr);

	batadv_tt_global_entry_free_ref(tt_global);



}



/* 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 BATADV_TT_CLIENT_ROAM flag and the

 * timer, otherwise we simply remove the originator scheduled for deletion.
@@ -1204,7 +1282,8 @@ struct batadv_orig_node *batadv_transtable_search(struct batadv_priv *bat_priv, 


	if (src && atomic_read(&bat_priv->ap_isolation)) {

		tt_local_entry = batadv_tt_local_hash_find(bat_priv, src);

		if (!tt_local_entry)

		if (!tt_local_entry ||

		    (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING))

			goto out;

	}

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