--- /dev/null
+From 3d999e5116f44b47c742aa16d6382721c360a6d0 Mon Sep 17 00:00:00 2001
+From: Simon Wunderlich <simon@open-mesh.com>
+Date: Thu, 23 May 2013 13:07:42 +0200
+Subject: [PATCH 10/10] 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>
+---
+ 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;
+--
+1.7.10.4
+