[B.A.T.M.A.N.] [RFC 09/23] batman-adv: OGMv2 - purge obsolete potential routers

Antonio Quartulli
2014-02-11T12:48:09Z

From: Antonio Quartulli <antonio@open-mesh.com>

If a neighbor is not forwarding OGMs since OGM_SEQ_RANGE
sequence numbers then it can be considered obsolete and
removed from the potential routers list. This may lead to a
route switch.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
---
bat_v_ogm.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
main.h | 3 ++
originator.c | 63 +++++++++++++++++++++++------------------
originator.h | 2 ++
types.h | 2 ++
5 files changed, 131 insertions(+), 31 deletions(-)

diff --git a/bat_v_ogm.c b/bat_v_ogm.c
index 4981d7c..5876164 100644
--- a/bat_v_ogm.c
+++ b/bat_v_ogm.c
@@ -79,8 +79,6 @@ batadv_v_ogm_neigh_new(struct batadv_priv *bat_priv,
return NULL;
}

- neigh_node->bat_v.elp_neigh = elp_neigh;
-
spin_lock_bh(&orig_node->neigh_list_lock);
tmp_neigh_node = batadv_neigh_node_get(orig_node, hard_iface, addr);
if (!tmp_neigh_node) {
@@ -98,6 +96,8 @@ batadv_v_ogm_neigh_new(struct batadv_priv *bat_priv,
"Creating new neighbor %pM for orig_node %pM on interface %s\n",
addr, orig_node->orig, hard_iface->net_dev->name);

+ neigh_node->bat_v.elp_neigh = elp_neigh;
+
return neigh_node;
}

@@ -235,6 +235,86 @@ void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *hard_iface)
rcu_read_unlock();
}

+static bool batadv_ogm_deselect_router(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node,
+ struct batadv_neigh_node *neigh)
+{
+ struct batadv_hard_iface *if_outgoing;
+ struct batadv_neigh_node *router;
+ bool removed = false;
+
+ router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
+ if (router == neigh)
+ batadv_update_route(bat_priv, orig_node, BATADV_IF_DEFAULT,
+ NULL);
+ if (router)
+ batadv_neigh_node_free_ref(router);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(if_outgoing, &batadv_hardif_list, list) {
+ if (if_outgoing->if_status != BATADV_IF_ACTIVE)
+ continue;
+
+ if (if_outgoing->soft_iface != bat_priv->soft_iface)
+ continue;
+
+ router = batadv_orig_router_get(orig_node, if_outgoing);
+ /* if this is the current router, unset it */
+ if (router == neigh) {
+ batadv_update_route(bat_priv, orig_node, if_outgoing,
+ NULL);
+ removed = true;
+ }
+ if (router)
+ batadv_neigh_node_free_ref(router);
+ }
+ rcu_read_unlock();
+
+ return removed;
+}
+
+/**
+ * batadv_v_ogm_purge_neighs - purge obsolete potential routers
+ * @bat_priv:
+ * @orig_node:
+ * @seqno:
+ *
+ * Purge routers from which this node did not receive at least
+ * BATADV_OGM_SEQ_RANGE OGMs
+ */
+static void batadv_v_ogm_purge_neighs(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node,
+ uint32_t seqno)
+{
+ struct batadv_neigh_node *neigh;
+ struct hlist_node *node_tmp;
+ int32_t diff;
+
+ rcu_read_lock();
+ spin_lock_bh(&orig_node->neigh_list_lock);
+ hlist_for_each_entry_safe(neigh, node_tmp, &orig_node->neigh_list,
+ list) {
+ diff = seqno - neigh->bat_v.last_recv_seqno;
+ if (diff < BATADV_OGM_SEQ_RANGE)
+ continue;
+
+ hlist_del_rcu(&neigh->list);
+ batadv_neigh_node_free_ref(neigh);
+ }
+ spin_unlock_bh(&orig_node->neigh_list_lock);
+
+ /* check if this neighbour is a router for any outgoing
+ * interface and possibly deselect it
+ */
+ if (batadv_ogm_deselect_router(bat_priv, orig_node, neigh))
+ goto out;
+
+ batadv_router_selection(bat_priv, orig_node);
+out:
+ rcu_read_unlock();
+ return;
+}
+
static void
batadv_v_ogm_orig_update(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
@@ -262,7 +342,7 @@ batadv_v_ogm_orig_update(struct batadv_priv *bat_priv,
batadv_orig_ifinfo_free_ref(orig_ifinfo);

/* if this neighbor already is our next hop there is nothing
- * to change
+ * to change. The router may have been changed by the purge routine
*/
router = batadv_orig_router_get(orig_node, if_outgoing);
if (router == neigh_node)
@@ -547,6 +627,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,

/* update the neigh_node information */
neigh_node->last_seen = jiffies;
+ neigh_node->bat_v.last_recv_seqno = ntohl(ogm2->seqno);

/* update the received metric to match the node topology: if this node
* is the first hop traversed by the OGM, then the metric is substituted
@@ -579,6 +660,11 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
}
rcu_read_unlock();

+ /* purge potential neighs not forwarding OGMs anymore.
+ * This may lead to a router change
+ */
+ batadv_v_ogm_purge_neighs(bat_priv, orig_node, ntohl(ogm2->seqno));
+
ret = NET_RX_SUCCESS;
consume_skb(skb);

diff --git a/main.h b/main.h
index 4badd01..47fb9ed 100644
--- a/main.h
+++ b/main.h
@@ -62,6 +62,9 @@
/* number of OGMs sent with the last tt diff */
#define BATADV_TT_OGM_APPEND_MAX 3

+/* number of missing OGMs to wait before considering a router unusable */
+#define BATADV_OGM_SEQ_RANGE 5
+
/* Time in which a client can roam at most ROAMING_MAX_COUNT times in
* milliseconds
*/
diff --git a/originator.c b/originator.c
index 9f2da37..447f417 100644
--- a/originator.c
+++ b/originator.c
@@ -837,6 +837,40 @@ batadv_find_best_neighbor(struct batadv_priv *bat_priv,
return best;
}

+void batadv_router_selection(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node)
+{
+ struct batadv_neigh_node *best_neigh_node;
+ struct batadv_hard_iface *hard_iface;
+
+ /* First for the default routing table ... */
+ best_neigh_node = batadv_find_best_neighbor(bat_priv, orig_node,
+ BATADV_IF_DEFAULT);
+ batadv_update_route(bat_priv, orig_node, BATADV_IF_DEFAULT,
+ best_neigh_node);
+ if (best_neigh_node)
+ batadv_neigh_node_free_ref(best_neigh_node);
+
+ /* ... then for all other outgoing interfaces. */
+ rcu_read_lock();
+ list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
+ if (hard_iface->if_status != BATADV_IF_ACTIVE)
+ continue;
+
+ if (hard_iface->soft_iface != bat_priv->soft_iface)
+ continue;
+
+ best_neigh_node = batadv_find_best_neighbor(bat_priv,
+ orig_node,
+ hard_iface);
+ batadv_update_route(bat_priv, orig_node, hard_iface,
+ best_neigh_node);
+ if (best_neigh_node)
+ batadv_neigh_node_free_ref(best_neigh_node);
+ }
+ rcu_read_unlock();
+}
+
/**
* batadv_purge_orig_node - purges obsolete information from an orig_node
* @bat_priv: the bat priv with all the soft interface information
@@ -850,8 +884,6 @@ batadv_find_best_neighbor(struct batadv_priv *bat_priv,
static bool batadv_purge_orig_node(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node)
{
- struct batadv_neigh_node *best_neigh_node;
- struct batadv_hard_iface *hard_iface;
bool changed;

if (batadv_has_timed_out(orig_node->last_seen,
@@ -868,32 +900,7 @@ static bool batadv_purge_orig_node(struct batadv_priv *bat_priv,
if (!changed)
return false;

- /* first for NULL ... */
- best_neigh_node = batadv_find_best_neighbor(bat_priv, orig_node,
- BATADV_IF_DEFAULT);
- batadv_update_route(bat_priv, orig_node, BATADV_IF_DEFAULT,
- best_neigh_node);
- if (best_neigh_node)
- batadv_neigh_node_free_ref(best_neigh_node);
-
- /* ... then for all other interfaces. */
- rcu_read_lock();
- list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
- if (hard_iface->if_status != BATADV_IF_ACTIVE)
- continue;
-
- if (hard_iface->soft_iface != bat_priv->soft_iface)
- continue;
-
- best_neigh_node = batadv_find_best_neighbor(bat_priv,
- orig_node,
- hard_iface);
- batadv_update_route(bat_priv, orig_node, hard_iface,
- best_neigh_node);
- if (best_neigh_node)
- batadv_neigh_node_free_ref(best_neigh_node);
- }
- rcu_read_unlock();
+ batadv_router_selection(bat_priv, orig_node);

return false;
}
diff --git a/originator.h b/originator.h
index db3a9ed..62e8e68 100644
--- a/originator.h
+++ b/originator.h
@@ -55,6 +55,8 @@ struct batadv_orig_ifinfo *
batadv_orig_ifinfo_new(struct batadv_orig_node *orig_node,
struct batadv_hard_iface *if_outgoing);
void batadv_orig_ifinfo_free_ref(struct batadv_orig_ifinfo *orig_ifinfo);
+void batadv_router_selection(struct batadv_priv *bat_priv,
+ struct batadv_orig_node *orig_node);

int batadv_orig_seq_print_text(struct seq_file *seq, void *offset);
int batadv_orig_hardif_seq_print_text(struct seq_file *seq, void *offset);
diff --git a/types.h b/types.h
index e9149d1..28f2b85 100644
--- a/types.h
+++ b/types.h
@@ -358,9 +358,11 @@ struct batadv_elp_neigh_node {
/**
* batadv_neigh_node_bat_v - B.A.T.M.A.N. V private neighbor information
* @elp_neigh: ELP private neighbour data
+ * @last_recv_seqno: last OGM seqno received through this neighbour
*/
struct batadv_neigh_node_bat_v {
struct batadv_elp_neigh_node *elp_neigh;
+ uint32_t last_recv_seqno;
};

/**
--
1.8.5.3