[DCCP]: Revert patch which disables bidirectional mode

This reverts an earlier patch which disabled bidirectional mode, meaning that
a listening (passive) socket was not allowed to write to the other (active)
end of the connection.

This mode had been disabled when there were problems with CCID3, but it
imposes a constraint on socket programming and thus hinders deployment.

A change is included to ignore RX feedback received by the TX CCID3 module.

Many thanks to Andre Noll for pointing out this issue.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 5361a4d..746f79d 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -545,12 +545,7 @@
 		/* set idle flag */
 		hctx->ccid3hctx_idle = 1;
 		break;
-	case TFRC_SSTATE_NO_SENT:
-		/*
-		 * XXX when implementing bidirectional rx/tx check this again
-		 */
-		DCCP_WARN("Illegal ACK received - no packet sent\n");
-		/* fall through */
+	case TFRC_SSTATE_NO_SENT:	/* fall through */
 	case TFRC_SSTATE_TERM:		/* ignore feedback when closing */
 		break;
 	}