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 <[email protected]>
---
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;
--
1.7.10.4
