[B.A.T.M.A.N.] [PATCH 08/28] batman-adv: protect originator nodes with reference counters

Sven Eckelmann
2011-03-05T12:28:22Z

net/batman-adv/originator.c | 61 ++++++++++++++++++++++++++++++++++++------
net/batman-adv/originator.h | 1 +
net/batman-adv/routing.c | 33 ++++++++++++++++-------
net/batman-adv/types.h | 2 +
4 files changed, 78 insertions(+), 19 deletions(-)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 5c32314..fcdb0b7 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -103,12 +103,13 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
return neigh_node;
}

-static void free_orig_node(void *data, void *arg)
+void orig_node_free_ref(struct kref *refcount)
{
struct hlist_node *node, *node_tmp;
struct neigh_node *neigh_node;
- struct orig_node *orig_node = (struct orig_node *)data;
- struct bat_priv *bat_priv = (struct bat_priv *)arg;
+ struct orig_node *orig_node;
+
+ orig_node = container_of(refcount, struct orig_node, refcount);

spin_lock_bh(&orig_node->neigh_list_lock);

@@ -122,7 +123,8 @@ static void free_orig_node(void *data, void *arg)
spin_unlock_bh(&orig_node->neigh_list_lock);

frag_list_free(&orig_node->frag_list);
- hna_global_del_orig(bat_priv, orig_node, "originator timed out");
+ hna_global_del_orig(orig_node->bat_priv, orig_node,
+ "originator timed out");

kfree(orig_node->bcast_own);
kfree(orig_node->bcast_own_sum);
@@ -131,17 +133,53 @@ static void free_orig_node(void *data, void *arg)

void originator_free(struct bat_priv *bat_priv)
{
- if (!bat_priv->orig_hash)
+ struct hashtable_t *hash = bat_priv->orig_hash;
+ struct hlist_node *walk, *safe;
+ struct hlist_head *head;
+ struct element_t *bucket;
+ spinlock_t *list_lock; /* spinlock to protect write access */
+ struct orig_node *orig_node;
+ int i;
+
+ if (!hash)
return;

cancel_delayed_work_sync(&bat_priv->orig_work);

spin_lock_bh(&bat_priv->orig_hash_lock);
- hash_delete(bat_priv->orig_hash, free_orig_node, bat_priv);
bat_priv->orig_hash = NULL;
+
+ for (i = 0; i < hash->size; i++) {
+ head = &hash->table[i];
+ list_lock = &hash->list_locks[i];
+
+ spin_lock_bh(list_lock);
+ hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) {
+ orig_node = bucket->data;
+
+ hlist_del_rcu(walk);
+ call_rcu(&bucket->rcu, bucket_free_rcu);
+ kref_put(&orig_node->refcount, orig_node_free_ref);
+ }
+ spin_unlock_bh(list_lock);
+ }
+
+ hash_destroy(hash);
spin_unlock_bh(&bat_priv->orig_hash_lock);
}

+static void bucket_free_orig_rcu(struct rcu_head *rcu)
+{
+ struct element_t *bucket;
+ struct orig_node *orig_node;
+
+ bucket = container_of(rcu, struct element_t, rcu);
+ orig_node = bucket->data;
+
+ kref_put(&orig_node->refcount, orig_node_free_ref);
+ kfree(bucket);
+}
+
/* this function finds or creates an originator entry for the given
* address if it does not exits */
struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
@@ -156,8 +194,10 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
addr));
rcu_read_unlock();

- if (orig_node)
+ if (orig_node) {
+ kref_get(&orig_node->refcount);
return orig_node;
+ }

bat_dbg(DBG_BATMAN, bat_priv,
"Creating new originator: %pM\n", addr);
@@ -168,7 +208,9 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)

INIT_HLIST_HEAD(&orig_node->neigh_list);
spin_lock_init(&orig_node->neigh_list_lock);
+ kref_init(&orig_node->refcount);

+ orig_node->bat_priv = bat_priv;
memcpy(orig_node->orig, addr, ETH_ALEN);
orig_node->router = NULL;
orig_node->hna_buff = NULL;
@@ -197,6 +239,8 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
if (hash_added < 0)
goto free_bcast_own_sum;

+ /* extra reference for return */
+ kref_get(&orig_node->refcount);
return orig_node;
free_bcast_own_sum:
kfree(orig_node->bcast_own_sum);
@@ -318,8 +362,7 @@ static void _purge_orig(struct bat_priv *bat_priv)
if (orig_node->gw_flags)
gw_node_delete(bat_priv, orig_node);
hlist_del_rcu(walk);
- call_rcu(&bucket->rcu, bucket_free_rcu);
- free_orig_node(orig_node, bat_priv);
+ call_rcu(&bucket->rcu, bucket_free_orig_rcu);
continue;
}

diff --git a/net/batman-adv/originator.h b/net/batman-adv/originator.h
index 88e5c60..edc64dc 100644
--- a/net/batman-adv/originator.h
+++ b/net/batman-adv/originator.h
@@ -25,6 +25,7 @@
int originator_init(struct bat_priv *bat_priv);
void originator_free(struct bat_priv *bat_priv);
void purge_orig_ref(struct bat_priv *bat_priv);
+void orig_node_free_ref(struct kref *refcount);
struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr);
struct neigh_node *create_neighbor(struct orig_node *orig_node,
struct orig_node *orig_neigh_node,
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 32ae04e..1c31a0e 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -311,6 +311,8 @@ static void update_orig(struct bat_priv *bat_priv,

neigh_node = create_neighbor(orig_node, orig_tmp,
ethhdr->h_source, if_incoming);
+
+ kref_put(&orig_tmp->refcount, orig_node_free_ref);
if (!neigh_node)
goto unlock;
} else
@@ -438,7 +440,7 @@ static char count_real_packets(struct ethhdr *ethhdr,
/* signalize caller that the packet is to be dropped. */
if (window_protected(bat_priv, seq_diff,
&orig_node->batman_seqno_reset))
- return -1;
+ goto err;

rcu_read_lock();
hlist_for_each_entry_rcu(tmp_neigh_node, node,
@@ -471,7 +473,12 @@ static char count_real_packets(struct ethhdr *ethhdr,
orig_node->last_real_seqno = batman_packet->seqno;
}

+ kref_put(&orig_node->refcount, orig_node_free_ref);
return is_duplicate;
+
+err:
+ kref_put(&orig_node->refcount, orig_node_free_ref);
+ return -1;
}

/* copy primary address for bonding */
@@ -686,7 +693,6 @@ void receive_bat_packet(struct ethhdr *ethhdr,
int offset;

orig_neigh_node = get_orig_node(bat_priv, ethhdr->h_source);
-
if (!orig_neigh_node)
return;

@@ -707,6 +713,7 @@ void receive_bat_packet(struct ethhdr *ethhdr,

bat_dbg(DBG_BATMAN, bat_priv, "Drop packet: "
"originator packet from myself (via neighbor)\n");
+ kref_put(&orig_neigh_node->refcount, orig_node_free_ref);
return;
}

@@ -727,13 +734,13 @@ void receive_bat_packet(struct ethhdr *ethhdr,
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: packet within seqno protection time "
"(sender: %pM)\n", ethhdr->h_source);
- return;
+ goto out;
}

if (batman_packet->tq == 0) {
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: originator packet with tq equal 0\n");
- return;
+ goto out;
}

/* avoid temporary routing loops */
@@ -747,7 +754,7 @@ void receive_bat_packet(struct ethhdr *ethhdr,
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: ignoring all rebroadcast packets that "
"may make me loop (sender: %pM)\n", ethhdr->h_source);
- return;
+ goto out;
}

/* if sender is a direct neighbor the sender mac equals
@@ -756,14 +763,14 @@ void receive_bat_packet(struct ethhdr *ethhdr,
orig_node :
get_orig_node(bat_priv, ethhdr->h_source));
if (!orig_neigh_node)
- return;
+ goto out_neigh;

/* drop packet if sender is not a direct neighbor and if we
* don't route towards it */
if (!is_single_hop_neigh && (!orig_neigh_node->router)) {
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: OGM via unknown neighbor!\n");
- return;
+ goto out_neigh;
}

is_bidirectional = is_bidirectional_neigh(orig_node, orig_neigh_node,
@@ -790,26 +797,32 @@ void receive_bat_packet(struct ethhdr *ethhdr,

bat_dbg(DBG_BATMAN, bat_priv, "Forwarding packet: "
"rebroadcast neighbor packet with direct link flag\n");
- return;
+ goto out_neigh;
}

/* multihop originator */
if (!is_bidirectional) {
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: not received via bidirectional link\n");
- return;
+ goto out_neigh;
}

if (is_duplicate) {
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: duplicate packet received\n");
- return;
+ goto out_neigh;
}

bat_dbg(DBG_BATMAN, bat_priv,
"Forwarding packet: rebroadcast originator packet\n");
schedule_forward_packet(orig_node, ethhdr, batman_packet,
0, hna_buff_len, if_incoming);
+
+out_neigh:
+ if (!is_single_hop_neigh)
+ kref_put(&orig_neigh_node->refcount, orig_node_free_ref);
+out:
+ kref_put(&orig_node->refcount, orig_node_free_ref);
}

int recv_bat_packet(struct sk_buff *skb, struct batman_if *batman_if)
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index d4fa727..ca4d42d 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -86,6 +86,8 @@ struct orig_node {
struct hlist_head neigh_list;
struct list_head frag_list;
spinlock_t neigh_list_lock; /* protects neighbor list */
+ struct kref refcount;
+ struct bat_priv *bat_priv;
unsigned long last_frag_packet;
struct {
uint8_t candidates;
--
1.7.2.3