From: Simon Wunderlich simon@open-mesh.com

When a packet is received from another node first and later from the best next hop, this packet is dropped. However the first OGM was sent with the BATADV_NOT_BEST_NEXT_HOP flag and thus dropped by neighbors. The late OGM from the best neighbor is then dropped because it is a duplicate.

If this situation happens constantly, a node might end up not forwarding the "valid" OGMs anymore, and nodes behind will starve from not getting valid OGMs.

Fix this by changing the is_duplicate behaviour: It will only mark duplicates which are received for the same neighbor. OGMs which are not from the best next hop will be dropped within batadv_iv_ogm_forward() anyway. Therefore, late OGMs are forwarded now and not dropped as duplicates.

Signed-off-by: Simon Wunderlich simon@open-mesh.com Signed-off-by: Antonio Quartulli ordex@autistici.org --- bat_iv_ogm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/bat_iv_ogm.c b/bat_iv_ogm.c index 8d87f87..bcd2527 100644 --- a/bat_iv_ogm.c +++ b/bat_iv_ogm.c @@ -948,7 +948,7 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr, struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface); struct batadv_orig_node *orig_node; struct batadv_neigh_node *tmp_neigh_node; - int is_duplicate = 0; + int is_dup = 0; int32_t seq_diff; int need_update = 0; int set_mark, ret = -1; @@ -972,16 +972,16 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr, rcu_read_lock(); hlist_for_each_entry_rcu(tmp_neigh_node, &orig_node->neigh_list, list) { - is_duplicate |= batadv_test_bit(tmp_neigh_node->real_bits, - orig_node->last_real_seqno, - seqno); - neigh_addr = tmp_neigh_node->addr; if (batadv_compare_eth(neigh_addr, ethhdr->h_source) && - tmp_neigh_node->if_incoming == if_incoming) + tmp_neigh_node->if_incoming == if_incoming) { + is_dup |= batadv_test_bit(tmp_neigh_node->real_bits, + orig_node->last_real_seqno, + seqno); set_mark = 1; - else + } else { set_mark = 0; + }

/* if the window moved, set the update flag. */ need_update |= batadv_bit_get_packet(bat_priv, @@ -1001,7 +1001,7 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr, orig_node->last_real_seqno = seqno; }

- ret = is_duplicate; + ret = is_dup;

out: spin_unlock_bh(&orig_node->ogm_cnt_lock);