tipc: implement configuration of UDP media MTU

In previous commit, we changed the default emulated MTU for UDP bearers
to 14k.

This commit adds the functionality to set/change the default value
by configuring new MTU for UDP media. UDP bearer(s) have to be disabled
and enabled back for the new MTU to take effect.

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: GhantaKrishnamurthy MohanKrishna <mohan.krishna.ghanta.krishnamurthy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index f7d47c89d658..a22caf9e5a18 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -1029,6 +1029,9 @@ static int __tipc_nl_add_media(struct tipc_nl_msg *msg,
                 goto prop_msg_full;
         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, media->window))
                 goto prop_msg_full;
+        if (media->type_id == TIPC_MEDIA_TYPE_UDP)
+                if (nla_put_u32(msg->skb, TIPC_NLA_PROP_MTU, media->mtu))
+                        goto prop_msg_full;
 
         nla_nest_end(msg->skb, prop);
         nla_nest_end(msg->skb, attrs);
@@ -1158,6 +1161,16 @@ int __tipc_nl_media_set(struct sk_buff *skb, struct genl_info *info)
                         m->priority = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
                 if (props[TIPC_NLA_PROP_WIN])
                         m->window = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
+                if (props[TIPC_NLA_PROP_MTU]) {
+                        if (m->type_id != TIPC_MEDIA_TYPE_UDP)
+                                return -EINVAL;
+#ifdef CONFIG_TIPC_MEDIA_UDP
+                        if (tipc_udp_mtu_bad(nla_get_u32
+                                             (props[TIPC_NLA_PROP_MTU])))
+                                return -EINVAL;
+                        m->mtu = nla_get_u32(props[TIPC_NLA_PROP_MTU]);
+#endif
+                }
         }
 
         return 0;