Repository : ssh://git@open-mesh.org/batman-adv
On branch : maint
commit 3d999e5116f44b47c742aa16d6382721c360a6d0 Author: Simon Wunderlich simon@open-mesh.com Date: Thu May 23 13:07:42 2013 +0200
batman-adv: forward late OGMs from best next hop
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 refining the duplicate checking behaviour: The actions should depend on whether it was a duplicate for a neighbor only or for the originator. OGMs which are not duplicates for a specific neighbor will now be considered in batadv_iv_ogm_forward(), but only actually forwarded for the best next hop. Therefore, late OGMs from the best next hop are forwarded now and not dropped as duplicates anymore.
Signed-off-by: Simon Wunderlich simon@open-mesh.com Signed-off-by: Marek Lindner lindner_marek@yahoo.de
3d999e5116f44b47c742aa16d6382721c360a6d0 bat_iv_ogm.c | 86 +++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 55 insertions(+), 31 deletions(-)
diff --git a/bat_iv_ogm.c b/bat_iv_ogm.c index 071f288..f680ee1 100644 --- a/bat_iv_ogm.c +++ b/bat_iv_ogm.c @@ -29,6 +29,21 @@ #include "bat_algo.h" #include "network-coding.h"
+/** + * batadv_dup_status - duplicate status + * @BATADV_NO_DUP: the packet is a duplicate + * @BATADV_ORIG_DUP: OGM is a duplicate in the originator (but not for the + * neighbor) + * @BATADV_NEIGH_DUP: OGM is a duplicate for the neighbor + * @BATADV_PROTECTED: originator is currently protected (after reboot) + */ +enum batadv_dup_status { + BATADV_NO_DUP = 0, + BATADV_ORIG_DUP, + BATADV_NEIGH_DUP, + BATADV_PROTECTED, +}; + static struct batadv_neigh_node * batadv_iv_ogm_neigh_new(struct batadv_hard_iface *hard_iface, const uint8_t *neigh_addr, @@ -650,7 +665,7 @@ batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv, const struct batadv_ogm_packet *batadv_ogm_packet, struct batadv_hard_iface *if_incoming, const unsigned char *tt_buff, - int is_duplicate) + enum batadv_dup_status dup_status) { struct batadv_neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL; struct batadv_neigh_node *router = NULL; @@ -676,7 +691,7 @@ batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv, continue; }
- if (is_duplicate) + if (dup_status != BATADV_NO_DUP) continue;
spin_lock_bh(&tmp_neigh_node->lq_update_lock); @@ -718,7 +733,7 @@ batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv, neigh_node->tq_avg = batadv_ring_buffer_avg(neigh_node->tq_recv); spin_unlock_bh(&neigh_node->lq_update_lock);
- if (!is_duplicate) { + if (dup_status == BATADV_NO_DUP) { orig_node->last_ttl = batadv_ogm_packet->header.ttl; neigh_node->last_ttl = batadv_ogm_packet->header.ttl; } @@ -902,15 +917,16 @@ out: return ret; }
-/* processes a batman packet for all interfaces, adjusts the sequence number and - * finds out whether it is a duplicate. - * returns: - * 1 the packet is a duplicate - * 0 the packet has not yet been received - * -1 the packet is old and has been received while the seqno window - * was protected. Caller should drop it. +/** + * batadv_iv_ogm_update_seqnos - process a batman packet for all interfaces, + * adjust the sequence number and find out whether it is a duplicate + * @ethhdr: ethernet header of the packet + * @batadv_ogm_packet: OGM packet to be considered + * @if_incoming: interface on which the OGM packet was received + * + * Returns duplicate status as enum batadv_dup_status */ -static int +static enum batadv_dup_status batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr, const struct batadv_ogm_packet *batadv_ogm_packet, const struct batadv_hard_iface *if_incoming) @@ -918,17 +934,18 @@ 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; int32_t seq_diff; int need_update = 0; - int set_mark, ret = -1; + int set_mark; + enum batadv_dup_status ret = BATADV_NO_DUP; uint32_t seqno = ntohl(batadv_ogm_packet->seqno); uint8_t *neigh_addr; uint8_t packet_count;
orig_node = batadv_get_orig_node(bat_priv, batadv_ogm_packet->orig); if (!orig_node) - return 0; + return BATADV_NO_DUP;
spin_lock_bh(&orig_node->ogm_cnt_lock); seq_diff = seqno - orig_node->last_real_seqno; @@ -936,22 +953,29 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr, /* signalize caller that the packet is to be dropped. */ if (!hlist_empty(&orig_node->neigh_list) && batadv_window_protected(bat_priv, seq_diff, - &orig_node->batman_seqno_reset)) + &orig_node->batman_seqno_reset)) { + ret = BATADV_PROTECTED; goto out; + }
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; + is_dup = batadv_test_bit(tmp_neigh_node->real_bits, + orig_node->last_real_seqno, + seqno); + if (batadv_compare_eth(neigh_addr, ethhdr->h_source) && - tmp_neigh_node->if_incoming == if_incoming) + tmp_neigh_node->if_incoming == if_incoming) { set_mark = 1; - else + if (is_dup) + ret = BATADV_NEIGH_DUP; + } else { set_mark = 0; + if (is_dup && (ret != BATADV_NEIGH_DUP)) + ret = BATADV_ORIG_DUP; + }
/* if the window moved, set the update flag. */ need_update |= batadv_bit_get_packet(bat_priv, @@ -971,8 +995,6 @@ batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr, orig_node->last_real_seqno = seqno; }
- ret = is_duplicate; - out: spin_unlock_bh(&orig_node->ogm_cnt_lock); batadv_orig_node_free_ref(orig_node); @@ -994,7 +1016,8 @@ static void batadv_iv_ogm_process(const struct ethhdr *ethhdr, int is_broadcast = 0, is_bidirect; bool is_single_hop_neigh = false; bool is_from_best_next_hop = false; - int is_duplicate, sameseq, simlar_ttl; + int sameseq, similar_ttl; + enum batadv_dup_status dup_status; uint32_t if_incoming_seqno; uint8_t *prev_sender;
@@ -1138,10 +1161,10 @@ static void batadv_iv_ogm_process(const struct ethhdr *ethhdr, if (!orig_node) return;
- is_duplicate = batadv_iv_ogm_update_seqnos(ethhdr, batadv_ogm_packet, - if_incoming); + dup_status = batadv_iv_ogm_update_seqnos(ethhdr, batadv_ogm_packet, + if_incoming);
- if (is_duplicate == -1) { + if (dup_status == BATADV_PROTECTED) { batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "Drop packet: packet within seqno protection time (sender: %pM)\n", ethhdr->h_source); @@ -1211,11 +1234,12 @@ static void batadv_iv_ogm_process(const struct ethhdr *ethhdr, * seqno and similar ttl as the non-duplicate */ sameseq = orig_node->last_real_seqno == ntohl(batadv_ogm_packet->seqno); - simlar_ttl = orig_node->last_ttl - 3 <= batadv_ogm_packet->header.ttl; - if (is_bidirect && (!is_duplicate || (sameseq && simlar_ttl))) + similar_ttl = orig_node->last_ttl - 3 <= batadv_ogm_packet->header.ttl; + if (is_bidirect && ((dup_status == BATADV_NO_DUP) || + (sameseq && similar_ttl))) batadv_iv_ogm_orig_update(bat_priv, orig_node, ethhdr, batadv_ogm_packet, if_incoming, - tt_buff, is_duplicate); + tt_buff, dup_status);
/* is single hop (direct) neighbor */ if (is_single_hop_neigh) { @@ -1236,7 +1260,7 @@ static void batadv_iv_ogm_process(const struct ethhdr *ethhdr, goto out_neigh; }
- if (is_duplicate) { + if (dup_status == BATADV_NEIGH_DUP) { batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "Drop packet: duplicate packet received\n"); goto out_neigh;