The following commit has been merged in the master branch: commit 068ee6e204e1f48ba24ec91ce40f5ca833a57a81 Author: Antonio Quartulli ordex@autistici.org Date: Sun Sep 23 22:38:37 2012 +0200

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: Antonio Quartulli ordex@autistici.org

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index cb8433a..dd2c254 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -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 */ - tt_local->common.flags &= ~BATADV_TT_CLIENT_PENDING; - goto out; + 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 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(); - /* 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; + 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) - goto out; + 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; }