[DCCP]: Move the ack vector code to net/dccp/ackvec.[ch]

Isolating it, that will be used when we introduce a CCID2 (TCP-Like)
implementation.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/dccp.h

@@ -353,14 +353,8 @@ static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req)
 
 extern struct inet_timewait_death_row dccp_death_row;
 
-/* Read about the ECN nonce to see why it is 253 */
-#define DCCP_MAX_ACK_VECTOR_LEN 253
-
 struct dccp_options_received {
-	u32	dccpor_ndp:24,
-		dccpor_ack_vector_len:8;
-	u32	dccpor_ack_vector_idx:10;
-	/* 22 bits hole, try to pack */
+	u32	dccpor_ndp; /* only 24 bits */
 	u32	dccpor_timestamp;
 	u32	dccpor_timestamp_echo;
 	u32	dccpor_elapsed_time;
@@ -394,6 +388,8 @@ static inline int dccp_list_has_service(const struct dccp_service_list *sl,
 	return 0;
 }
 
+struct dccp_ackvec;
+
 /**
  * struct dccp_sock - DCCP socket state
  *
@@ -414,7 +410,7 @@ static inline int dccp_list_has_service(const struct dccp_service_list *sl,
  * @dccps_packet_size - Set thru setsockopt
  * @dccps_role - Role of this sock, one of %dccp_role
  * @dccps_ndp_count - number of Non Data Packets since last data packet
- * @dccps_hc_rx_ackpkts - receiver half connection acked packets
+ * @dccps_hc_rx_ackvec - rx half connection ack vector
  */
 struct dccp_sock {
 	/* inet_connection_sock has to be the first member of dccp_sock */
@@ -439,7 +435,7 @@ struct dccp_sock {
 	__u32				dccps_pmtu_cookie;
 	__u32				dccps_mss_cache;
 	struct dccp_options		dccps_options;
-	struct dccp_ackpkts		*dccps_hc_rx_ackpkts;
+	struct dccp_ackvec		*dccps_hc_rx_ackvec;
 	void				*dccps_hc_rx_ccid_private;
 	void				*dccps_hc_tx_ccid_private;
 	struct ccid			*dccps_hc_rx_ccid;

net/dccp/Makefile

@@ -3,6 +3,8 @@ obj-$(CONFIG_IP_DCCP) += dccp.o
 dccp-y := ccid.o input.o ipv4.o minisocks.o options.o output.o proto.o \
 	  timer.o
 
+dccp-$(CONFIG_IP_DCCP_ACKVEC) += ackvec.o
+
 obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o
 
 dccp_diag-y := diag.o

net/dccp/ackvec.h

+#ifndef _ACKVEC_H
+#define _ACKVEC_H
+/*
+ *  net/dccp/ackvec.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <linux/config.h>
+#include <linux/compiler.h>
+#include <linux/time.h>
+#include <linux/types.h>
+
+/* Read about the ECN nonce to see why it is 253 */
+#define DCCP_MAX_ACKVEC_LEN 253
+
+#define DCCP_ACKVEC_STATE_RECEIVED	0
+#define DCCP_ACKVEC_STATE_ECN_MARKED	(1 << 6)
+#define DCCP_ACKVEC_STATE_NOT_RECEIVED	(3 << 6)
+
+#define DCCP_ACKVEC_STATE_MASK		0xC0 /* 11000000 */
+#define DCCP_ACKVEC_LEN_MASK		0x3F /* 00111111 */
+
+/** struct dccp_ackvec - ack vector
+ *
+ * This data structure is the one defined in the DCCP draft
+ * Appendix A.
+ *
+ * @dccpav_buf_head - circular buffer head
+ * @dccpav_buf_tail - circular buffer tail
+ * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the
+ * 		       buffer (i.e. %dccpav_buf_head)
+ * @dccpav_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
+ * 		       by the buffer with State 0
+ *
+ * Additionally, the HC-Receiver must keep some information about the
+ * Ack Vectors it has recently sent. For each packet sent carrying an
+ * Ack Vector, it remembers four variables:
+ *
+ * @dccpav_ack_seqno - the Sequence Number used for the packet
+ * 		       (HC-Receiver seqno)
+ * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
+ * @dccpav_ack_ackno - the Acknowledgement Number used for the packet
+ * 		       (HC-Sender seqno)
+ * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
+ *
+ * @dccpav_buf_len	- circular buffer length
+ * @dccpav_time		- the time in usecs
+ * @dccpav_buf - circular buffer of acknowledgeable packets
+ */
+struct dccp_ackvec {
+	unsigned int	dccpav_buf_head;
+	unsigned int	dccpav_buf_tail;
+	u64		dccpav_buf_ackno;
+	u64		dccpav_ack_seqno;
+	u64		dccpav_ack_ackno;
+	unsigned int	dccpav_ack_ptr;
+	unsigned int	dccpav_sent_len;
+	unsigned int	dccpav_vec_len;
+	unsigned int	dccpav_buf_len;
+	struct timeval	dccpav_time;
+	u8		dccpav_buf_nonce;
+	u8		dccpav_ack_nonce;
+	u8		dccpav_buf[0];
+};
+
+struct sock;
+struct sk_buff;
+
+#ifdef CONFIG_IP_DCCP_ACKVEC
+extern struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
+					  const unsigned int __nocast priority);
+extern void dccp_ackvec_free(struct dccp_ackvec *av);
+
+extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+			   const u64 ackno, const u8 state);
+
+extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
+					struct sock *sk, const u64 ackno);
+extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+			     const u8 opt, const u8 *value, const u8 len);
+
+extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
+
+static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
+{
+	return av->dccpav_sent_len != av->dccpav_vec_len;
+}
+#else /* CONFIG_IP_DCCP_ACKVEC */
+static inline struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
+					   const unsigned int __nocast priority)
+{
+	return NULL;
+}
+
+static inline void dccp_ackvec_free(struct dccp_ackvec *av)
+{
+}
+
+static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+				  const u64 ackno, const u8 state)
+{
+	return -1;
+}
+
+static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
+					       struct sock *sk, const u64 ackno)
+{
+}
+
+static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+				    const u8 opt, const u8 *value, const u8 len)
+{
+	return -1;
+}
+
+static inline int dccp_insert_option_ackvec(const struct sock *sk,
+					    const struct sk_buff *skb)
+{
+	return -1;
+}
+
+static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
+{
+	return 0;
+}
+#endif /* CONFIG_IP_DCCP_ACKVEC */
+#endif /* _ACKVEC_H */

net/dccp/dccp.h

@@ -17,6 +17,7 @@
 #include <net/snmp.h>
 #include <net/sock.h>
 #include <net/tcp.h>
+#include "ackvec.h"
 
 #ifdef CONFIG_IP_DCCP_DEBUG
 extern int dccp_debug;
@@ -358,6 +359,17 @@ static inline void dccp_update_gss(struct sock *sk, u64 seq)
 		       (dp->dccps_gss -
 			dp->dccps_options.dccpo_sequence_window + 1));
 }
+				
+static inline int dccp_ack_pending(const struct sock *sk)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	return dp->dccps_timestamp_echo != 0 ||
+#ifdef CONFIG_IP_DCCP_ACKVEC
+	       (dp->dccps_options.dccpo_send_ack_vector &&
+		dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
+#endif
+	       inet_csk_ack_scheduled(sk);
+}
 
 extern void dccp_insert_options(struct sock *sk, struct sk_buff *skb);
 extern void dccp_insert_option_elapsed_time(struct sock *sk,
@@ -371,65 +383,6 @@ extern void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 
 extern struct socket *dccp_ctl_socket;
 
-#define DCCP_ACKPKTS_STATE_RECEIVED	0
-#define DCCP_ACKPKTS_STATE_ECN_MARKED	(1 << 6)
-#define DCCP_ACKPKTS_STATE_NOT_RECEIVED	(3 << 6)
-
-#define DCCP_ACKPKTS_STATE_MASK		0xC0 /* 11000000 */
-#define DCCP_ACKPKTS_LEN_MASK		0x3F /* 00111111 */
-
-/** struct dccp_ackpkts - acknowledgeable packets
- *
- * This data structure is the one defined in the DCCP draft
- * Appendix A.
- *
- * @dccpap_buf_head - circular buffer head
- * @dccpap_buf_tail - circular buffer tail
- * @dccpap_buf_ackno - ack # of the most recent packet acknowledgeable in the
- * 		       buffer (i.e. %dccpap_buf_head)
- * @dccpap_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
- * 		       by the buffer with State 0
- *
- * Additionally, the HC-Receiver must keep some information about the
- * Ack Vectors it has recently sent. For each packet sent carrying an
- * Ack Vector, it remembers four variables:
- *
- * @dccpap_ack_seqno - the Sequence Number used for the packet
- * 		       (HC-Receiver seqno)
- * @dccpap_ack_ptr - the value of buf_head at the time of acknowledgement.
- * @dccpap_ack_ackno - the Acknowledgement Number used for the packet
- * 		       (HC-Sender seqno)
- * @dccpap_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
- *
- * @dccpap_buf_len - circular buffer length
- * @dccpap_time		- the time in usecs
- * @dccpap_buf - circular buffer of acknowledgeable packets
- */
-struct dccp_ackpkts {
-	unsigned int		dccpap_buf_head;
-	unsigned int		dccpap_buf_tail;
-	u64			dccpap_buf_ackno;
-	u64			dccpap_ack_seqno;
-	u64			dccpap_ack_ackno;
-	unsigned int		dccpap_ack_ptr;
-	unsigned int		dccpap_buf_vector_len;
-	unsigned int		dccpap_ack_vector_len;
-	unsigned int		dccpap_buf_len;
-	struct timeval		dccpap_time;
-	u8			dccpap_buf_nonce;
-	u8			dccpap_ack_nonce;
-	u8			dccpap_buf[0];
-};
-
-extern struct dccp_ackpkts *
-		dccp_ackpkts_alloc(unsigned int len,
-				  const unsigned int __nocast priority);
-extern void dccp_ackpkts_free(struct dccp_ackpkts *ap);
-extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, const struct sock *sk,
-			    u64 ackno, u8 state);
-extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
-					 struct sock *sk, u64 ackno);
-
 extern void dccp_timestamp(const struct sock *sk, struct timeval *tv);
 
 static inline suseconds_t timeval_usecs(const struct timeval *tv)
@@ -470,15 +423,4 @@ static inline void timeval_sub_usecs(struct timeval *tv,
 	}
 }
 
-#ifdef CONFIG_IP_DCCP_DEBUG
-extern void dccp_ackvector_print(const u64 ackno,
-				 const unsigned char *vector, int len);
-extern void dccp_ackpkts_print(const struct dccp_ackpkts *ap);
-#else
-static inline void dccp_ackvector_print(const u64 ackno,
-					const unsigned char *vector,
-					int len) { }
-static inline void dccp_ackpkts_print(const struct dccp_ackpkts *ap) { }
-#endif
-
 #endif /* _DCCP_H */

net/dccp/input.c

@@ -16,6 +16,7 @@
 
 #include <net/sock.h>
 
+#include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
 
@@ -60,8 +61,8 @@ static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
 	struct dccp_sock *dp = dccp_sk(sk);
 
 	if (dp->dccps_options.dccpo_send_ack_vector)
-		dccp_ackpkts_check_rcv_ackno(dp->dccps_hc_rx_ackpkts, sk,
-					     DCCP_SKB_CB(skb)->dccpd_ack_seq);
+		dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
+					    DCCP_SKB_CB(skb)->dccpd_ack_seq);
 }
 
 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
@@ -164,37 +165,11 @@ int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
 		dccp_event_ack_recv(sk, skb);
 
-	/*
-	 * FIXME: check ECN to see if we should use
-	 * DCCP_ACKPKTS_STATE_ECN_MARKED
-	 */
-	if (dp->dccps_options.dccpo_send_ack_vector) {
-		struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
-
-		if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts, sk,
-				     DCCP_SKB_CB(skb)->dccpd_seq,
-				     DCCP_ACKPKTS_STATE_RECEIVED)) {
-			LIMIT_NETDEBUG(KERN_WARNING "DCCP: acknowledgeable "
-						    "packets buffer full!\n");
-			ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-			inet_csk_schedule_ack(sk);
-			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
-						  TCP_DELACK_MIN,
-						  DCCP_RTO_MAX);
-			goto discard;
-		}
-
-		/*
-		 * FIXME: this activation is probably wrong, have to study more
-		 * TCP delack machinery and how it fits into DCCP draft, but
-		 * for now it kinda "works" 8)
-		 */
-		if (!inet_csk_ack_scheduled(sk)) {
-			inet_csk_schedule_ack(sk);
-			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 5 * HZ,
-						  DCCP_RTO_MAX);
-		}
-	}
+	if (dp->dccps_options.dccpo_send_ack_vector &&
+	    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
+			    DCCP_SKB_CB(skb)->dccpd_seq,
+			    DCCP_ACKVEC_STATE_RECEIVED))
+		goto discard;
 
 	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
 	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
@@ -495,29 +470,11 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 		ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
 		ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
 
-		/*
-		 * FIXME: check ECN to see if we should use
-		 * DCCP_ACKPKTS_STATE_ECN_MARKED
-		 */
-		if (dp->dccps_options.dccpo_send_ack_vector) {
-			if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts, sk,
-					     dcb->dccpd_seq,
-					     DCCP_ACKPKTS_STATE_RECEIVED))
-				goto discard;
-			/*
-			 * FIXME: this activation is probably wrong, have to
-			 * study more TCP delack machinery and how it fits into
-			 * DCCP draft, but for now it kinda "works" 8)
-			 */
-			if ((dp->dccps_hc_rx_ackpkts->dccpap_ack_seqno ==
-			     DCCP_MAX_SEQNO + 1) &&
-			    !inet_csk_ack_scheduled(sk)) {
-				inet_csk_schedule_ack(sk);
-				inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
-							  TCP_DELACK_MIN,
-							  DCCP_RTO_MAX);
-			}
-		}
+ 		if (dp->dccps_options.dccpo_send_ack_vector &&
+		    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
+ 				    DCCP_SKB_CB(skb)->dccpd_seq,
+ 				    DCCP_ACKVEC_STATE_RECEIVED))
+ 			goto discard;
 	}
 
 	/*

net/dccp/ipv4.c

@@ -23,6 +23,7 @@
 #include <net/tcp_states.h>
 #include <net/xfrm.h>
 
+#include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
 
@@ -1112,45 +1113,7 @@ int dccp_v4_rcv(struct sk_buff *skb)
 		goto discard_it;
 
 	dh = dccp_hdr(skb);
-#if 0
-	/*
-	 * Use something like this to simulate some DATA/DATAACK loss to test
-	 * dccp_ackpkts_add, you'll get something like this on a session that
-	 * sends 10 DATA/DATAACK packets:
-	 *
-	 * ackpkts_print: 281473596467422 |0,0|3,0|0,0|3,0|0,0|3,0|0,0|3,0|0,1|
-	 *
-	 * 0, 0 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == just this packet
-	 * 0, 1 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == two adjacent packets
-	 * 						   with the same state
-	 * 3, 0 means: DCCP_ACKPKTS_STATE_NOT_RECEIVED, RLE == just this packet
-	 *
-	 * So...
-	 *
-	 * 281473596467422 was received
-	 * 281473596467421 was not received
-	 * 281473596467420 was received
-	 * 281473596467419 was not received
-	 * 281473596467418 was received
-	 * 281473596467417 was not received
-	 * 281473596467416 was received
-	 * 281473596467415 was not received
-	 * 281473596467414 was received
-	 * 281473596467413 was received (this one was the 3way handshake
-	 * 				 RESPONSE)
-	 *
-	 */
-	if (dh->dccph_type == DCCP_PKT_DATA ||
-	    dh->dccph_type == DCCP_PKT_DATAACK) {
-		static int discard = 0;
 
-		if (discard) {
-			discard = 0;
-			goto discard_it;
-		}
-		discard = 1;
-	}
-#endif
 	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(skb);
 	DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
 
@@ -1264,11 +1227,9 @@ static int dccp_v4_init_sock(struct sock *sk)
 	do_gettimeofday(&dp->dccps_epoch);
 
 	if (dp->dccps_options.dccpo_send_ack_vector) {
-		dp->dccps_hc_rx_ackpkts =
-			dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN,
-					   GFP_KERNEL);
-
-		if (dp->dccps_hc_rx_ackpkts == NULL)
+		dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
+							   GFP_KERNEL);
+		if (dp->dccps_hc_rx_ackvec == NULL)
 			return -ENOMEM;
 	}
 
@@ -1288,8 +1249,10 @@ static int dccp_v4_init_sock(struct sock *sk)
 		    dp->dccps_hc_tx_ccid == NULL) {
 			ccid_exit(dp->dccps_hc_rx_ccid, sk);
 			ccid_exit(dp->dccps_hc_tx_ccid, sk);
-			dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
-			dp->dccps_hc_rx_ackpkts = NULL;
+			if (dp->dccps_options.dccpo_send_ack_vector) {
+				dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+				dp->dccps_hc_rx_ackvec = NULL;
+			}
 			dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
 			return -ENOMEM;
 		}
@@ -1331,8 +1294,10 @@ static int dccp_v4_destroy_sock(struct sock *sk)
 
 	ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
 	ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
-	dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
-	dp->dccps_hc_rx_ackpkts = NULL;
+	if (dp->dccps_options.dccpo_send_ack_vector) {
+		dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+		dp->dccps_hc_rx_ackvec = NULL;
+	}
 	ccid_exit(dp->dccps_hc_rx_ccid, sk);
 	ccid_exit(dp->dccps_hc_tx_ccid, sk);
 	dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;

net/dccp/minisocks.c

@@ -19,6 +19,7 @@
 #include <net/xfrm.h>
 #include <net/inet_timewait_sock.h>
 
+#include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
 
@@ -94,23 +95,23 @@ struct sock *dccp_create_openreq_child(struct sock *sk,
 		struct dccp_sock *newdp = dccp_sk(newsk);
 
 		newdp->dccps_role	   = DCCP_ROLE_SERVER;
-		newdp->dccps_hc_rx_ackpkts = NULL;
+		newdp->dccps_hc_rx_ackvec  = NULL;
 		newdp->dccps_service_list  = NULL;
 		newdp->dccps_service	   = dreq->dreq_service;
 		newicsk->icsk_rto	   = DCCP_TIMEOUT_INIT;
 		do_gettimeofday(&newdp->dccps_epoch);
 
 		if (newdp->dccps_options.dccpo_send_ack_vector) {
-			newdp->dccps_hc_rx_ackpkts =
-				dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN,
-						   GFP_ATOMIC);
+			newdp->dccps_hc_rx_ackvec =
+				dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
+						  GFP_ATOMIC);
 			/*
 			 * XXX: We're using the same CCIDs set on the parent,
 			 * i.e. sk_clone copied the master sock and left the
 			 * CCID pointers for this child, that is why we do the
 			 * __ccid_get calls.
 			 */
-			if (unlikely(newdp->dccps_hc_rx_ackpkts == NULL))
+			if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
 				goto out_free;
 		}
 
@@ -118,7 +119,7 @@ struct sock *dccp_create_openreq_child(struct sock *sk,
 					     newsk) != 0 ||
 			     ccid_hc_tx_init(newdp->dccps_hc_tx_ccid,
 				     	     newsk) != 0)) {
-			dccp_ackpkts_free(newdp->dccps_hc_rx_ackpkts);
+			dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
 			ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk);
 			ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk);
 out_free:

net/dccp/output.c

@@ -16,6 +16,7 @@
 
 #include <net/sock.h>
 
+#include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
 
@@ -225,7 +226,6 @@ int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
 		err = dccp_wait_for_ccid(sk, skb, timeo);
 
 	if (err == 0) {
-		const struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
 		struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 		const int len = skb->len;
 
@@ -236,15 +236,7 @@ int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
 						  inet_csk(sk)->icsk_rto,
 						  DCCP_RTO_MAX);
 			dcb->dccpd_type = DCCP_PKT_DATAACK;
-			/*
-			 * FIXME: we really should have a
-			 * dccps_ack_pending or use icsk.
-			 */
-		} else if (inet_csk_ack_scheduled(sk) ||
-			   dp->dccps_timestamp_echo != 0 ||
-			   (dp->dccps_options.dccpo_send_ack_vector &&
-			    ap->dccpap_buf_ackno != DCCP_MAX_SEQNO + 1 &&
-			    ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1))
+		} else if (dccp_ack_pending(sk))
 			dcb->dccpd_type = DCCP_PKT_DATAACK;
 		else
 			dcb->dccpd_type = DCCP_PKT_DATA;