rxrpc: Break MTU determination from ICMP into its own function

Break MTU determination from ICMP out into its own function to reduce the
complexity of the error report handler.

Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index 2c2df3a5d1b915ee3a47f746f97534142dc3f7d3..80de84257227c7580a2a8aeb191d052d811cffdb 100644 (file)
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -71,6 +71,45 @@ static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
        return rxrpc_lookup_peer_rcu(local, &srx);
 }
 
+/*
+ * Handle an MTU/fragmentation problem.
+ */
+static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
+{
+       u32 mtu = serr->ee.ee_info;
+
+       _net("Rx ICMP Fragmentation Needed (%d)", mtu);
+
+       /* wind down the local interface MTU */
+       if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
+               peer->if_mtu = mtu;
+               _net("I/F MTU %u", mtu);
+       }
+
+       if (mtu == 0) {
+               /* they didn't give us a size, estimate one */
+               mtu = peer->if_mtu;
+               if (mtu > 1500) {
+                       mtu >>= 1;
+                       if (mtu < 1500)
+                               mtu = 1500;
+               } else {
+                       mtu -= 100;
+                       if (mtu < peer->hdrsize)
+                               mtu = peer->hdrsize + 4;
+               }
+       }
+
+       if (mtu < peer->mtu) {
+               spin_lock_bh(&peer->lock);
+               peer->mtu = mtu;
+               peer->maxdata = peer->mtu - peer->hdrsize;
+               spin_unlock_bh(&peer->lock);
+               _net("Net MTU %u (maxdata %u)",
+                    peer->mtu, peer->maxdata);
+       }
+}
+
 /*
  * handle an error received on the local endpoint
  */
@@ -126,50 +165,26 @@ void rxrpc_error_report(struct sock *sk)
                return;
        }
 
-       if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
-           serr->ee.ee_type == ICMP_DEST_UNREACH &&
-           serr->ee.ee_code == ICMP_FRAG_NEEDED
-           ) {
-               u32 mtu = serr->ee.ee_info;
-
-               _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
-
-               /* wind down the local interface MTU */
-               if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
-                       peer->if_mtu = mtu;
-                       _net("I/F MTU %u", mtu);
-               }
-
-               if (mtu == 0) {
-                       /* they didn't give us a size, estimate one */
-                       mtu = peer->if_mtu;
-                       if (mtu > 1500) {
-                               mtu >>= 1;
-                               if (mtu < 1500)
-                                       mtu = 1500;
-                       } else {
-                               mtu -= 100;
-                               if (mtu < peer->hdrsize)
-                                       mtu = peer->hdrsize + 4;
-                       }
-               }
-
-               if (mtu < peer->mtu) {
-                       spin_lock_bh(&peer->lock);
-                       peer->mtu = mtu;
-                       peer->maxdata = peer->mtu - peer->hdrsize;
-                       spin_unlock_bh(&peer->lock);
-                       _net("Net MTU %u (maxdata %u)",
-                            peer->mtu, peer->maxdata);
-               }
+       if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
+            serr->ee.ee_type == ICMP_DEST_UNREACH &&
+            serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
+               rxrpc_adjust_mtu(peer, serr);
+               rxrpc_free_skb(skb);
+               skb = NULL;
+               goto out;
        }
 
+out:
        rcu_read_unlock();
        rxrpc_put_peer(peer);
 
-       /* pass the transport ref to error_handler to release */
-       skb_queue_tail(&trans->error_queue, skb);
-       rxrpc_queue_work(&trans->error_handler);
+       if (skb) {
+               /* pass the transport ref to error_handler to release */
+               skb_queue_tail(&trans->error_queue, skb);
+               rxrpc_queue_work(&trans->error_handler);
+       } else {
+               rxrpc_put_transport(trans);
+       }
        _leave("");
 }