[DCCP]: Fix RESET handling in dccp_rcv_state_process

To avoid holding TIMEWAIT state for sockets in the LISTEN state.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/input.c

@@ -402,7 +402,48 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 	const int old_state = sk->sk_state;
 	int queued = 0;
 
-	if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING) {
+	/*
+	 *  Step 3: Process LISTEN state
+	 *  	(Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
+	 *
+	 *     If S.state == LISTEN,
+	 *	  If P.type == Request or P contains a valid Init Cookie
+	 *	  	option,
+	 *	     * Must scan the packet's options to check for an Init
+	 *		Cookie.  Only the Init Cookie is processed here,
+	 *		however; other options are processed in Step 8.  This
+	 *		scan need only be performed if the endpoint uses Init
+	 *		Cookies *
+	 *	     * Generate a new socket and switch to that socket *
+	 *	     Set S := new socket for this port pair
+	 *	     S.state = RESPOND
+	 *	     Choose S.ISS (initial seqno) or set from Init Cookie
+	 *	     Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
+	 *	     Continue with S.state == RESPOND
+	 *	     * A Response packet will be generated in Step 11 *
+	 *	  Otherwise,
+	 *	     Generate Reset(No Connection) unless P.type == Reset
+	 *	     Drop packet and return
+	 *
+	 * NOTE: the check for the packet types is done in
+	 *	 dccp_rcv_state_process
+	 */
+	if (sk->sk_state == DCCP_LISTEN) {
+		if (dh->dccph_type == DCCP_PKT_REQUEST) {
+			if (dccp_v4_conn_request(sk, skb) < 0)
+				return 1;
+
+			/* FIXME: do congestion control initialization */
+			goto discard;
+		}
+		if (dh->dccph_type == DCCP_PKT_RESET)
+			goto discard;
+
+		/* Caller (dccp_v4_do_rcv) will send Reset(No Connection)*/
+		return 1;
+	}
+
+	if (sk->sk_state != DCCP_REQUESTING) {
 		if (dccp_check_seqno(sk, skb))
 			goto discard;
 
@@ -484,23 +525,6 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 	case DCCP_CLOSED:
 		return 1;
 
-	case DCCP_LISTEN:
-		if (dh->dccph_type == DCCP_PKT_ACK ||
-		    dh->dccph_type == DCCP_PKT_DATAACK)
-			return 1;
-
-		if (dh->dccph_type == DCCP_PKT_RESET)
-			goto discard;
-
-		if (dh->dccph_type == DCCP_PKT_REQUEST) {
-			if (dccp_v4_conn_request(sk, skb) < 0)
-				return 1;
-
-			/* FIXME: do congestion control initialization */
-			goto discard;
-		}
-		goto discard;
-
 	case DCCP_REQUESTING:
 		/* FIXME: do congestion control initialization */