[B.A.T.M.A.N.] [PATCH 17/20] batman-adv: Add duplicate checks for multicast data

Linus Lüssing
2010-12-07T22:32:27Z

This commit adds duplicate checks to avoid endless rebroadcasts in the
case of forwarding multicast data packets via broadcasting.

Signed-off-by: Linus Lüssing <linus.luessing@saxnet.de>
---
originator.c | 2 ++
routing.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
types.h | 3 +++
3 files changed, 52 insertions(+), 1 deletions(-)

diff --git a/originator.c b/originator.c
index 39ce8d5..f882292 100644
--- a/originator.c
+++ b/originator.c
@@ -154,6 +154,8 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
orig_node->num_mca = 0;
orig_node->bcast_seqno_reset = jiffies - 1
- msecs_to_jiffies(RESET_PROTECTION_MS);
+ orig_node->mcast_seqno_reset = jiffies - 1
+ - msecs_to_jiffies(RESET_PROTECTION_MS);
orig_node->batman_seqno_reset = jiffies - 1
- msecs_to_jiffies(RESET_PROTECTION_MS);

diff --git a/routing.c b/routing.c
index f9582be..19f045a 100644
--- a/routing.c
+++ b/routing.c
@@ -1391,8 +1391,11 @@ int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
int recv_mcast_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 mcast_packet *mcast_packet;
struct ethhdr *ethhdr;
MC_LIST *mc_entry;
+ int32_t seq_diff;
unsigned long flags;
int ret = 1;
int hdr_size = sizeof(struct mcast_packet);
@@ -1402,10 +1405,53 @@ int recv_mcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
check_broadcast_packet(skb, hdr_size) < 0)
return NET_RX_DROP;

+ mcast_packet = (struct mcast_packet *)skb->data;
+
+ /* ignore broadcasts originated by myself */
+ if (is_my_mac(mcast_packet->orig))
+ return NET_RX_DROP;
+
+ if (mcast_packet->ttl < 2)
+ return NET_RX_DROP;
+
+ spin_lock_irqsave(&bat_priv->orig_hash_lock, flags);
+ orig_node = ((struct orig_node *)
+ hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
+ mcast_packet->orig));
+
+ if (orig_node == NULL) {
+ spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
+ return NET_RX_DROP;
+ }
+
+ /* check whether the packet is a duplicate */
+ if (get_bit_status(orig_node->mcast_bits,
+ orig_node->last_mcast_seqno,
+ ntohl(mcast_packet->seqno))) {
+ spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
+ return NET_RX_DROP;
+ }
+
+ seq_diff = ntohl(mcast_packet->seqno) - orig_node->last_mcast_seqno;
+
+ /* check whether the packet is old and the host just restarted. */
+ if (window_protected(bat_priv, seq_diff,
+ &orig_node->mcast_seqno_reset)) {
+ spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
+ return NET_RX_DROP;
+ }
+
+ /* mark broadcast in flood history, update window position
+ * if required. */
+ if (bit_get_packet(bat_priv, orig_node->mcast_bits, seq_diff, 1))
+ orig_node->last_mcast_seqno = ntohl(mcast_packet->seqno);
+
+ spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
+
/* forward multicast packet if necessary */
route_mcast_packet(skb, bat_priv);

- ethhdr = (struct ethhdr *)(skb->data + sizeof(struct mcast_packet));
+ ethhdr = (struct ethhdr *)(mcast_packet + 1);

/* multicast for me? */
MC_LIST_LOCK(recv_if->soft_iface, flags);
diff --git a/types.h b/types.h
index c12fd2c..890822f 100644
--- a/types.h
+++ b/types.h
@@ -74,6 +74,7 @@ struct orig_node {
int tq_asym_penalty;
unsigned long last_valid;
unsigned long bcast_seqno_reset;
+ unsigned long mcast_seqno_reset;
unsigned long batman_seqno_reset;
uint8_t gw_flags;
uint8_t flags;
@@ -84,7 +85,9 @@ struct orig_node {
uint32_t last_real_seqno;
uint8_t last_ttl;
TYPE_OF_WORD bcast_bits[NUM_WORDS];
+ TYPE_OF_WORD mcast_bits[NUM_WORDS];
uint32_t last_bcast_seqno;
+ uint32_t last_mcast_seqno;
struct list_head neigh_list;
struct list_head frag_list;
unsigned long last_frag_packet;
--
1.7.1