The two commits noted below added calls to ip_hdr() and ipv6_hdr(). They need a correctly set skb network header.

Unfortunately we cannot rely on the device drivers to set it for us. Therefore setting it in the beginning of the according ndo_start_xmit handler.

Fixes: 405cc1e5 ("batman-adv: Modified forwarding behaviour for multicast packets") Fixes: 1c090349 ("batman-adv: Add IPv4 link-local/IPv6-ll-all-nodes multicast support") Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue ---

Three notes:

* Pending question on netdev, we should probably wait a few more days before applying this patch.

* Back in Nov. 2014 for the original multicast bridge patchset Simon suggested moving the skb_set_network_header() call to within the according multicast functions: https://lists.open-mesh.org/pipermail/b.a.t.m.a.n/2014-November/012573.html

I would like to submit patches for master afterwards though to change some raw skb->data access and hdr_size math to skb_network_header() calls as I think they might be easier to read and safer. (for skb->data you always have to go back the whole call chain and check for any skb pulls etc. to know where skb->data points to, same for hdr_size to know it's value as it's passed through mutliple layers of functions)

So I thought it'd be good to have the skb_set_network_header() in a good place for that already.

* The "network_offset += VETH_HLEN" is not strictly necessary since the multicast optimizations won't apply for vlans yet and the ip_hdr()/ipv6_hdr() calls are never reached in that case. But again, I thought it would be cleaner that way.

soft-interface.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/soft-interface.c b/soft-interface.c index 7841a4b..eb87fd9 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -178,6 +178,7 @@ static int batadv_interface_tx(struct sk_buff *skb, int gw_mode; enum batadv_forw_mode forw_mode; struct batadv_orig_node *mcast_single_orig = NULL; + int network_offset = ETH_HLEN;

if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE) goto dropped; @@ -190,14 +191,18 @@ static int batadv_interface_tx(struct sk_buff *skb, case ETH_P_8021Q: vhdr = vlan_eth_hdr(skb);

- if (vhdr->h_vlan_encapsulated_proto != ethertype) + if (vhdr->h_vlan_encapsulated_proto != ethertype) { + network_offset += VLAN_HLEN; break; + }

/* fall through */ case ETH_P_BATMAN: goto dropped; }

+ skb_set_network_header(skb, network_offset); + if (batadv_bla_tx(bat_priv, skb, vid)) goto dropped;