rxrpc: Only take the rwind and mtu values from latest ACK

[ Upstream commit 298bc15b2079c324e82d0a6fda39c3d762af7282 ]

Move the out-of-order and duplicate ACK packet check to before the call to
rxrpc_input_ackinfo() so that the receive window size and MTU size are only
checked in the latest ACK packet and don't regress.

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 3a501bf0fc1a781679ce012e317cb8c8bee47a82..ea506a77f3c811950b8c6ebbf8203c8d797766ca 100644 (file)
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -806,6 +806,16 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
                                  rxrpc_propose_ack_respond_to_ack);
        }
 
+       /* Discard any out-of-order or duplicate ACKs. */
+       if (before_eq(sp->hdr.serial, call->acks_latest)) {
+               _debug("discard ACK %d <= %d",
+                      sp->hdr.serial, call->acks_latest);
+               return;
+       }
+       call->acks_latest_ts = skb->tstamp;
+       call->acks_latest = sp->hdr.serial;
+
+       /* Parse rwind and mtu sizes if provided. */
        ioffset = offset + nr_acks + 3;
        if (skb->len >= ioffset + sizeof(buf.info)) {
                if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
@@ -827,15 +837,6 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
                return;
        }
 
-       /* Discard any out-of-order or duplicate ACKs. */
-       if (before_eq(sp->hdr.serial, call->acks_latest)) {
-               _debug("discard ACK %d <= %d",
-                      sp->hdr.serial, call->acks_latest);
-               return;
-       }
-       call->acks_latest_ts = skb->tstamp;
-       call->acks_latest = sp->hdr.serial;
-
        if (before(hard_ack, call->tx_hard_ack) ||
            after(hard_ack, call->tx_top))
                return rxrpc_proto_abort("AKW", call, 0);