This is a note to let you know that I've just added the patch titled
batman-adv: mcast: fix duplicate mcast packets from BLA backbone to mesh
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
batman-adv-mcast-fix-duplicate-mcast-packets-from-bla-backbone-to-mesh.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Nov 23 01:39:02 PM CET 2021
From: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Date: Sat, 20 Nov 2021 13:39:34 +0100
Subject: batman-adv: mcast: fix duplicate mcast packets from BLA backbone to mesh
To: stable@xxxxxxxxxxxxxxx
Cc: b.a.t.m.a.n@xxxxxxxxxxxxxxxxxxx, "Linus Lüssing" <linus.luessing@xxxxxxxxx>, "Simon Wunderlich" <sw@xxxxxxxxxxxxxxxxxx>, "Sven Eckelmann" <sven@xxxxxxxxxxxxx>
Message-ID: <20211120123939.260723-7-sven@xxxxxxxxxxxxx>
From: Linus Lüssing <linus.luessing@xxxxxxxxx>
commit 2369e827046920ef0599e6a36b975ac5c0a359c2 upstream.
Scenario:
* Multicast frame send from BLA backbone gateways (multiple nodes
with their bat0 bridged together, with BLA enabled) sharing the same
LAN to nodes in the mesh
Issue:
* Nodes receive the frame multiple times on bat0 from the mesh,
once from each foreign BLA backbone gateway which shares the same LAN
with another
For multicast frames via batman-adv broadcast packets coming from the
same BLA backbone but from different backbone gateways duplicates are
currently detected via a CRC history of previously received packets.
However this CRC so far was not performed for multicast frames received
via batman-adv unicast packets. Fixing this by appyling the same check
for such packets, too.
Room for improvements in the future: Ideally we would introduce the
possibility to not only claim a client, but a complete originator, too.
This would allow us to only send a multicast-in-unicast packet from a BLA
backbone gateway claiming the node and by that avoid potential redundant
transmissions in the first place.
Fixes: fe2da6ff27c7 ("batman-adv: add broadcast duplicate check")
Signed-off-by: Linus Lüssing <linus.luessing@xxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
[ bp: 4.4 backported: adjust context, correct fixes line, switch back to
int return type ]
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/batman-adv/bridge_loop_avoidance.c | 99 ++++++++++++++++++++++++++++-----
1 file changed, 85 insertions(+), 14 deletions(-)
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -1370,31 +1370,32 @@ int batadv_bla_init(struct batadv_priv *
}
/**
- * batadv_bla_check_bcast_duplist
+ * batadv_bla_check_duplist() - Check if a frame is in the broadcast dup.
* @bat_priv: the bat priv with all the soft interface information
- * @skb: contains the bcast_packet to be checked
+ * @skb: contains the multicast packet to be checked
+ * @payload_ptr: pointer to position inside the head buffer of the skb
+ * marking the start of the data to be CRC'ed
+ * @orig: originator mac address, NULL if unknown
*
- * check if it is on our broadcast list. Another gateway might
- * have sent the same packet because it is connected to the same backbone,
- * so we have to remove this duplicate.
+ * Check if it is on our broadcast list. Another gateway might have sent the
+ * same packet because it is connected to the same backbone, so we have to
+ * remove this duplicate.
*
* This is performed by checking the CRC, which will tell us
* with a good chance that it is the same packet. If it is furthermore
* sent by another host, drop it. We allow equal packets from
* the same host however as this might be intended.
*/
-int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
- struct sk_buff *skb)
+static int batadv_bla_check_duplist(struct batadv_priv *bat_priv,
+ struct sk_buff *skb, u8 *payload_ptr,
+ const u8 *orig)
{
int i, curr, ret = 0;
__be32 crc;
- struct batadv_bcast_packet *bcast_packet;
struct batadv_bcast_duplist_entry *entry;
- bcast_packet = (struct batadv_bcast_packet *)skb->data;
-
/* calculate the crc ... */
- crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));
+ crc = batadv_skb_crc32(skb, payload_ptr);
spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
@@ -1413,8 +1414,21 @@ int batadv_bla_check_bcast_duplist(struc
if (entry->crc != crc)
continue;
- if (batadv_compare_eth(entry->orig, bcast_packet->orig))
- continue;
+ /* are the originators both known and not anonymous? */
+ if (orig && !is_zero_ether_addr(orig) &&
+ !is_zero_ether_addr(entry->orig)) {
+ /* If known, check if the new frame came from
+ * the same originator:
+ * We are safe to take identical frames from the
+ * same orig, if known, as multiplications in
+ * the mesh are detected via the (orig, seqno) pair.
+ * So we can be a bit more liberal here and allow
+ * identical frames from the same orig which the source
+ * host might have sent multiple times on purpose.
+ */
+ if (batadv_compare_eth(entry->orig, orig))
+ continue;
+ }
/* this entry seems to match: same crc, not too old,
* and from another gw. therefore return 1 to forbid it.
@@ -1430,7 +1444,14 @@ int batadv_bla_check_bcast_duplist(struc
entry = &bat_priv->bla.bcast_duplist[curr];
entry->crc = crc;
entry->entrytime = jiffies;
- ether_addr_copy(entry->orig, bcast_packet->orig);
+
+ /* known originator */
+ if (orig)
+ ether_addr_copy(entry->orig, orig);
+ /* anonymous originator */
+ else
+ eth_zero_addr(entry->orig);
+
bat_priv->bla.bcast_duplist_curr = curr;
out:
@@ -1440,6 +1461,48 @@ out:
}
/**
+ * batadv_bla_check_ucast_duplist() - Check if a frame is in the broadcast dup.
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: contains the multicast packet to be checked, decapsulated from a
+ * unicast_packet
+ *
+ * Check if it is on our broadcast list. Another gateway might have sent the
+ * same packet because it is connected to the same backbone, so we have to
+ * remove this duplicate.
+ *
+ * Return: true if a packet is in the duplicate list, false otherwise.
+ */
+static bool batadv_bla_check_ucast_duplist(struct batadv_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ return batadv_bla_check_duplist(bat_priv, skb, (u8 *)skb->data, NULL);
+}
+
+/**
+ * batadv_bla_check_bcast_duplist() - Check if a frame is in the broadcast dup.
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: contains the bcast_packet to be checked
+ *
+ * Check if it is on our broadcast list. Another gateway might have sent the
+ * same packet because it is connected to the same backbone, so we have to
+ * remove this duplicate.
+ *
+ * Return: true if a packet is in the duplicate list, false otherwise.
+ */
+int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ struct batadv_bcast_packet *bcast_packet;
+ u8 *payload_ptr;
+
+ bcast_packet = (struct batadv_bcast_packet *)skb->data;
+ payload_ptr = (u8 *)(bcast_packet + 1);
+
+ return batadv_bla_check_duplist(bat_priv, skb, payload_ptr,
+ bcast_packet->orig);
+}
+
+/**
* batadv_bla_is_backbone_gw_orig
* @bat_priv: the bat priv with all the soft interface information
* @orig: originator mac address
@@ -1591,6 +1654,14 @@ int batadv_bla_rx(struct batadv_priv *ba
packet_type == BATADV_UNICAST)
goto handled;
+ /* potential duplicates from foreign BLA backbone gateways via
+ * multicast-in-unicast packets
+ */
+ if (is_multicast_ether_addr(ethhdr->h_dest) &&
+ packet_type == BATADV_UNICAST &&
+ batadv_bla_check_ucast_duplist(bat_priv, skb))
+ goto handled;
+
ether_addr_copy(search_claim.addr, ethhdr->h_source);
search_claim.vid = vid;
claim = batadv_claim_hash_find(bat_priv, &search_claim);
Patches currently in stable-queue which might be from sven@xxxxxxxxxxxxx are
queue-4.4/batman-adv-consider-fragmentation-for-needed_headroom.patch
queue-4.4/ath9k-fix-potential-interrupt-storm-on-queue-reset.patch
queue-4.4/batman-adv-set-.owner-to-this_module.patch
queue-4.4/batman-adv-mcast-fix-duplicate-mcast-packets-from-bla-backbone-to-mesh.patch
queue-4.4/batman-adv-fix-multicast-tt-issues-with-bogus-roam-flags.patch
queue-4.4/batman-adv-mcast-fix-duplicate-mcast-packets-in-bla-backbone-from-lan.patch
queue-4.4/batman-adv-reserve-needed_-room-for-fragments.patch
queue-4.4/net-batman-adv-fix-error-handling.patch
queue-4.4/batman-adv-keep-fragments-equally-sized.patch
queue-4.4/batman-adv-avoid-warn_on-timing-related-checks.patch
queue-4.4/batman-adv-prevent-duplicated-softif_vlan-entry.patch
queue-4.4/batman-adv-don-t-always-reallocate-the-fragmentation-skb-head.patch
queue-4.4/batman-adv-mcast-fix-duplicate-mcast-packets-in-bla-backbone-from-mesh.patch
