[PATCH 0/2] pull request for net: batman-adv 2018-03-26

[PATCH 0/2] pull request for net: batman-adv 2018-03-26

[Simon Wunderlich]

Hi David,

here are two late bugfixes for batman-adv which we would like to have in net
if still possible.

Please pull or let me know of any problem!

Thank you,
      Simon

The following changes since commit fc04fdb2c8a894283259f5621d31d75610701091:

  batman-adv: Fix skbuff rcsum on packet reroute (2018-03-18 13:20:32 +0100)

are available in the git repository at:

  git://git.open-mesh.org/linux-merge.git tags/batadv-net-for-davem-20180326

for you to fetch changes up to a752c0a4524889cdc0765925258fd1fd72344100:

  batman-adv: fix packet loss for broadcasted DHCP packets to a server (2018-03-24 10:25:49 +0100)

----------------------------------------------------------------
Here are some batman-adv bugfixes:

 - fix multicast-via-unicast transmissions for AP isolation and gateway
   extension, by Linus Luessing (2 patches)

----------------------------------------------------------------
Linus Lüssing (2):
      batman-adv: fix multicast-via-unicast transmission with AP isolation
      batman-adv: fix packet loss for broadcasted DHCP packets to a server

 net/batman-adv/gateway_client.c | 5 ++++-
 net/batman-adv/multicast.c      | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

[PATCH 1/2] batman-adv: fix multicast-via-unicast transmission with AP isolation

[Simon Wunderlich]

From: Linus Lüssing <linus.luessing@c0d3.blue>

For multicast frames AP isolation is only supposed to be checked on
the receiving nodes and never on the originating one.

Furthermore, the isolation or wifi flag bits should only be intepreted
as such for unicast and never multicast TT entries.

By injecting flags to the multicast TT entry claimed by a single
target node it was verified in tests that this multicast address
becomes unreachable, leading to packet loss.

Omitting the "src" parameter to the batadv_transtable_search() call
successfully skipped the AP isolation check and made the target
reachable again.

Fixes: 1d8ab8d3c176 ("batman-adv: Modified forwarding behaviour for multicast packets")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/multicast.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index d70640135e3a..ee56af5c43e0 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -814,8 +814,8 @@ static struct batadv_orig_node *
 batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
 			      struct ethhdr *ethhdr)
 {
-	return batadv_transtable_search(bat_priv, ethhdr->h_source,
-					ethhdr->h_dest, BATADV_NO_FLAGS);
+	return batadv_transtable_search(bat_priv, NULL, ethhdr->h_dest,
+					BATADV_NO_FLAGS);
 }
 
 /**
-- 
2.11.0

[PATCH 2/2] batman-adv: fix packet loss for broadcasted DHCP packets to a server

[Simon Wunderlich]

From: Linus Lüssing <linus.luessing@c0d3.blue>

DHCP connectivity issues can currently occur if the following conditions
are met:

1) A DHCP packet from a client to a server
2) This packet has a multicast destination
3) This destination has a matching entry in the translation table
   (FF:FF:FF:FF:FF:FF for IPv4, 33:33:00:01:00:02/33:33:00:01:00:03
    for IPv6)
4) The orig-node determined by TT for the multicast destination
   does not match the orig-node determined by best-gateway-selection

In this case the DHCP packet will be dropped.

The "gateway-out-of-range" check is supposed to only be applied to
unicasted DHCP packets to a specific DHCP server.

In that case dropping the the unicasted frame forces the client to
retry via a broadcasted one, but now directed to the new best
gateway.

A DHCP packet with broadcast/multicast destination is already ensured to
always be delivered to the best gateway. Dropping a multicasted
DHCP packet here will only prevent completing DHCP as there is no
other fallback.

So far, it seems the unicast check was implicitly performed by
expecting the batadv_transtable_search() to return NULL for multicast
destinations. However, a multicast address could have always ended up in
the translation table and in fact is now common.

To fix this potential loss of a DHCP client-to-server packet to a
multicast address this patch adds an explicit multicast destination
check to reliably bail out of the gateway-out-of-range check for such
destinations.

The issue and fix were tested in the following three node setup:

- Line topology, A-B-C
- A: gateway client, DHCP client
- B: gateway server, hop-penalty increased: 30->60, DHCP server
- C: gateway server, code modifications to announce FF:FF:FF:FF:FF:FF

Without this patch, A would never transmit its DHCP Discover packet
due to an always "out-of-range" condition. With this patch,
a full DHCP handshake between A and B was possible again.

Fixes: be7af5cf9cae ("batman-adv: refactoring gateway handling code")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/gateway_client.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index 37fe9a644f22..808d2dd4a839 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -746,7 +746,7 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 {
 	struct batadv_neigh_node *neigh_curr = NULL;
 	struct batadv_neigh_node *neigh_old = NULL;
-	struct batadv_orig_node *orig_dst_node;
+	struct batadv_orig_node *orig_dst_node = NULL;
 	struct batadv_gw_node *gw_node = NULL;
 	struct batadv_gw_node *curr_gw = NULL;
 	struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
@@ -757,6 +757,9 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 
 	vid = batadv_get_vid(skb, 0);
 
+	if (is_multicast_ether_addr(ethhdr->h_dest))
+		goto out;
+
 	orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 						 ethhdr->h_dest, vid);
 	if (!orig_dst_node)
-- 
2.11.0

Re: [PATCH 0/2] pull request for net: batman-adv 2018-03-26

[David Miller]

From: Simon Wunderlich <sw@simonwunderlich.de>
Date: Mon, 26 Mar 2018 14:47:52 +0200

> here are two late bugfixes for batman-adv which we would like to have in net
> if still possible.
> 
> Please pull or let me know of any problem!

Pulled, thank you Simon.