[DCCP] ackvec: Fix how DCCP_ACKVEC_STATE_NOT_RECEIVED is used

Fix the way state is masked out.  DCCP_ACKVEC_STATE_NOT_RECEIVED is
defined as appears in the packet, therefore bit shifting is not
required.  This fix allows CCID2 to correctly detect losses.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dccp/ackvec.c

@@ -436,8 +436,7 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
 		break;
 found:
 		if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, ackno)) {
-			const u8 state = (*vector &
-					  DCCP_ACKVEC_STATE_MASK) >> 6;
+			const u8 state = *vector & DCCP_ACKVEC_STATE_MASK;
 			if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
 #ifdef CONFIG_IP_DCCP_DEBUG
 				struct dccp_sock *dp = dccp_sk(sk);

net/dccp/ccids/ccid2.c

@@ -582,8 +582,8 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 			 * run length
 			 */
 			while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
-				const u8 state = (*vector &
-						  DCCP_ACKVEC_STATE_MASK) >> 6;
+				const u8 state = *vector &
+						 DCCP_ACKVEC_STATE_MASK;
 
 				/* new packet received or marked */
 				if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&