The following commit has been merged in the master branch: commit 7caf69fb9c5017df01945a1861c042f6aa08edeb Author: Linus Lüssing linus.luessing@web.de Date: Tue Sep 18 03:01:08 2012 +0200

batman-adv: Fix symmetry check / route flapping in multi interface setups

If receiving an OGM from a neighbor other than the currently selected and if it has the same TQ then we are supposed to switch if this neighbor provides a more symmetric link than the currently selected one.

However this symmetry check currently is broken if the interface of the neighbor we received the OGM from and the one of the currently selected neighbor differ: We are currently trying to determine the symmetry of the link towards the selected router via the link we received the OGM from instead of just checking via the link towards the currently selected router.

This leads to way more route switches than necessary and can lead to permanent route flapping in many common multi interface setups.

This patch fixes this issue by using the right interface for this symmetry check.

Signed-off-by: Linus Lüssing linus.luessing@web.de

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c index e877af8..469daab 100644 --- a/net/batman-adv/bat_iv_ogm.c +++ b/net/batman-adv/bat_iv_ogm.c @@ -642,7 +642,8 @@ batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv, struct batadv_neigh_node *router = NULL; struct batadv_orig_node *orig_node_tmp; struct hlist_node *node; - uint8_t bcast_own_sum_orig, bcast_own_sum_neigh; + int if_num; + uint8_t sum_orig, sum_neigh; uint8_t *neigh_addr;

batadv_dbg(BATADV_DBG_BATMAN, bat_priv, @@ -727,17 +728,17 @@ batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv, if (router && (neigh_node->tq_avg == router->tq_avg)) { orig_node_tmp = router->orig_node; spin_lock_bh(&orig_node_tmp->ogm_cnt_lock); - bcast_own_sum_orig = - orig_node_tmp->bcast_own_sum[if_incoming->if_num]; + if_num = router->if_incoming->if_num; + sum_orig = orig_node_tmp->bcast_own_sum[if_num]; spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

orig_node_tmp = neigh_node->orig_node; spin_lock_bh(&orig_node_tmp->ogm_cnt_lock); - bcast_own_sum_neigh = - orig_node_tmp->bcast_own_sum[if_incoming->if_num]; + if_num = neigh_node->if_incoming->if_num; + sum_neigh = orig_node_tmp->bcast_own_sum[if_num]; spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

- if (bcast_own_sum_orig >= bcast_own_sum_neigh) + if (sum_orig >= sum_neigh) goto update_tt; }