[B.A.T.M.A.N.] [RFC v4 10/19] batman-adv: Add fragmentation mesh genl configuration

Sven Eckelmann
2019-01-19T15:56:17Z

The mesh interface can fragment unicast packets when the packet size
exceeds the outgoing slave/hard-interface MTU.

The BATADV_CMD_SET_MESH/BATADV_CMD_GET_MESH commands allow to set/get the
configuration of this feature using the BATADV_ATTR_FRAGMENTATION_ENABLED
attribute. Setting the u8 to zero will disable this feature and setting it
to something else is enabling this feature.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
Cc: Andreas Langer <an.langer@gmx.de>
Cc: Martin Hundeboll <martin@hundeboll.net>
Cc: Marek Lindner <mareklindner@neomailbox.ch>
---
include/uapi/linux/batman_adv.h | 7 +++++++
net/batman-adv/netlink.c | 12 ++++++++++++
2 files changed, 19 insertions(+)

diff --git a/include/uapi/linux/batman_adv.h b/include/uapi/linux/batman_adv.h
index f303a149..847841b8 100644
--- a/include/uapi/linux/batman_adv.h
+++ b/include/uapi/linux/batman_adv.h
@@ -396,6 +396,13 @@ enum batadv_nl_attrs {
*/
BATADV_ATTR_DISTRIBUTED_ARP_TABLE_ENABLED,

+ /**
+ * @BATADV_ATTR_FRAGMENTATION_ENABLED: whether the data traffic going
+ * through the mesh will be fragmented or silently discarded if the
+ * packet size exceeds the outgoing interface MTU.
+ */
+ BATADV_ATTR_FRAGMENTATION_ENABLED,
+
/* add attributes above here, update the policy in netlink.c */

/**
diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 68440d2f..45f6aee5 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -146,6 +146,7 @@ static const struct nla_policy batadv_netlink_policy[NUM_BATADV_ATTR] = {
[BATADV_ATTR_BONDING_ENABLED] = { .type = NLA_U8 },
[BATADV_ATTR_BRIDGE_LOOP_AVOIDANCE_ENABLED] = { .type = NLA_U8 },
[BATADV_ATTR_DISTRIBUTED_ARP_TABLE_ENABLED] = { .type = NLA_U8 },
+ [BATADV_ATTR_FRAGMENTATION_ENABLED] = { .type = NLA_U8 },
};

/**
@@ -298,6 +299,10 @@ static int batadv_netlink_mesh_put(struct sk_buff *msg,
goto nla_put_failure;
#endif /* CONFIG_BATMAN_ADV_DAT */

+ if (nla_put_u8(msg, BATADV_ATTR_FRAGMENTATION_ENABLED,
+ !!atomic_read(&bat_priv->fragmentation)))
+ goto nla_put_failure;
+
if (primary_if)
batadv_hardif_put(primary_if);

@@ -432,6 +437,13 @@ static int batadv_netlink_set_mesh(struct sk_buff *skb, struct genl_info *info)
}
#endif /* CONFIG_BATMAN_ADV_DAT */

+ if (info->attrs[BATADV_ATTR_FRAGMENTATION_ENABLED]) {
+ attr = info->attrs[BATADV_ATTR_FRAGMENTATION_ENABLED];
+
+ atomic_set(&bat_priv->fragmentation, !!nla_get_u8(attr));
+ batadv_update_min_mtu(bat_priv->soft_iface);
+ }
+
batadv_netlink_notify_mesh(bat_priv);

return 0;
--
2.20.1