[linux-next] LinuxNextTracking branch, master, updated. next-20110624

batman at open-mesh.org batman at open-mesh.org
Fri Jun 24 16:09:07 CEST 2011


The following commit has been merged in the master branch:
commit f3e0008f01b275bd08bd416cfcaa7021dd6bc277
Author: Marek Lindner <lindner_marek at yahoo.de>
Date:   Tue Jan 25 21:52:11 2011 +0000

    batman-adv: make broadcast seqno operations atomic
    
    Batman-adv could receive several payload broadcasts at the same time
    that would trigger access to the broadcast seqno sliding window to
    determine whether this is a new broadcast or not. If these incoming
    broadcasts are accessing the sliding window simultaneously it could
    be left in an inconsistent state. Therefore it is necessary to make
    sure this access is atomic.
    
    Reported-by: Linus Lüssing <linus.luessing at web.de>
    Signed-off-by: Marek Lindner <lindner_marek at yahoo.de>

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 61299da..d9a8e31 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -215,6 +215,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
 	INIT_HLIST_HEAD(&orig_node->neigh_list);
 	INIT_LIST_HEAD(&orig_node->bond_list);
 	spin_lock_init(&orig_node->ogm_cnt_lock);
+	spin_lock_init(&orig_node->bcast_seqno_lock);
 	spin_lock_init(&orig_node->neigh_list_lock);
 	kref_init(&orig_node->refcount);
 
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 29a689a..ce68815 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -1473,81 +1473,93 @@ int recv_ucast_frag_packet(struct sk_buff *skb, struct batman_if *recv_if)
 int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
 {
 	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
-	struct orig_node *orig_node;
+	struct orig_node *orig_node = NULL;
 	struct bcast_packet *bcast_packet;
 	struct ethhdr *ethhdr;
 	int hdr_size = sizeof(struct bcast_packet);
+	int ret = NET_RX_DROP;
 	int32_t seq_diff;
 
 	/* drop packet if it has not necessary minimum size */
 	if (unlikely(!pskb_may_pull(skb, hdr_size)))
-		return NET_RX_DROP;
+		goto out;
 
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* packet with broadcast indication but unicast recipient */
 	if (!is_broadcast_ether_addr(ethhdr->h_dest))
-		return NET_RX_DROP;
+		goto out;
 
 	/* packet with broadcast sender address */
 	if (is_broadcast_ether_addr(ethhdr->h_source))
-		return NET_RX_DROP;
+		goto out;
 
 	/* ignore broadcasts sent by myself */
 	if (is_my_mac(ethhdr->h_source))
-		return NET_RX_DROP;
+		goto out;
 
 	bcast_packet = (struct bcast_packet *)skb->data;
 
 	/* ignore broadcasts originated by myself */
 	if (is_my_mac(bcast_packet->orig))
-		return NET_RX_DROP;
+		goto out;
 
 	if (bcast_packet->ttl < 2)
-		return NET_RX_DROP;
+		goto out;
 
 	spin_lock_bh(&bat_priv->orig_hash_lock);
 	rcu_read_lock();
 	orig_node = ((struct orig_node *)
 		     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
 			       bcast_packet->orig));
+
+	if (!orig_node)
+		goto rcu_unlock;
+
+	kref_get(&orig_node->refcount);
 	rcu_read_unlock();
 
-	if (!orig_node) {
-		spin_unlock_bh(&bat_priv->orig_hash_lock);
-		return NET_RX_DROP;
-	}
+	spin_lock_bh(&orig_node->bcast_seqno_lock);
 
 	/* check whether the packet is a duplicate */
-	if (get_bit_status(orig_node->bcast_bits,
-			   orig_node->last_bcast_seqno,
-			   ntohl(bcast_packet->seqno))) {
-		spin_unlock_bh(&bat_priv->orig_hash_lock);
-		return NET_RX_DROP;
-	}
+	if (get_bit_status(orig_node->bcast_bits, orig_node->last_bcast_seqno,
+			   ntohl(bcast_packet->seqno)))
+		goto spin_unlock;
 
 	seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
 
 	/* check whether the packet is old and the host just restarted. */
 	if (window_protected(bat_priv, seq_diff,
-			     &orig_node->bcast_seqno_reset)) {
-		spin_unlock_bh(&bat_priv->orig_hash_lock);
-		return NET_RX_DROP;
-	}
+			     &orig_node->bcast_seqno_reset))
+		goto spin_unlock;
 
 	/* mark broadcast in flood history, update window position
 	 * if required. */
 	if (bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
 		orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
 
+	spin_unlock_bh(&orig_node->bcast_seqno_lock);
 	spin_unlock_bh(&bat_priv->orig_hash_lock);
+
 	/* rebroadcast packet */
 	add_bcast_packet_to_list(bat_priv, skb);
 
 	/* broadcast for me */
 	interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
+	ret = NET_RX_SUCCESS;
+	goto out;
 
-	return NET_RX_SUCCESS;
+rcu_unlock:
+	rcu_read_unlock();
+	spin_unlock_bh(&bat_priv->orig_hash_lock);
+	goto out;
+spin_unlock:
+	spin_unlock_bh(&orig_node->bcast_seqno_lock);
+	spin_unlock_bh(&bat_priv->orig_hash_lock);
+out:
+	if (orig_node)
+		kref_put(&orig_node->refcount, orig_node_free_ref);
+	return ret;
 }
 
 int recv_vis_packet(struct sk_buff *skb, struct batman_if *recv_if)
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 9a14276..e1f3e5e 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -90,6 +90,8 @@ struct orig_node {
 	spinlock_t ogm_cnt_lock; /* protects: bcast_own, bcast_own_sum,
 				  * neigh_node->real_bits,
 				  * neigh_node->real_packet_count */
+	spinlock_t bcast_seqno_lock; /* protects bcast_bits,
+				      *	 last_bcast_seqno */
 	atomic_t bond_candidates;
 	struct list_head bond_list;
 };

-- 
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