Merge branch 'master' into for-linus

Conflicts:
	include/linux/percpu.h
	mm/percpu.c

22 files changed, 411 insertions, 610 deletions

diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index 6df6f8ac963..117fb093dca 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -62,22 +62,18 @@ struct ccid_operations {
 	void		(*ccid_hc_tx_exit)(struct sock *sk);
 	void		(*ccid_hc_rx_packet_recv)(struct sock *sk,
 						  struct sk_buff *skb);
-	int		(*ccid_hc_rx_parse_options)(struct sock *sk,
-						    unsigned char option,
-						    unsigned char len, u16 idx,
-						    unsigned char* value);
+	int		(*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt,
+						    u8 opt, u8 *val, u8 len);
 	int		(*ccid_hc_rx_insert_options)(struct sock *sk,
 						     struct sk_buff *skb);
 	void		(*ccid_hc_tx_packet_recv)(struct sock *sk,
 						  struct sk_buff *skb);
-	int		(*ccid_hc_tx_parse_options)(struct sock *sk,
-						    unsigned char option,
-						    unsigned char len, u16 idx,
-						    unsigned char* value);
+	int		(*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt,
+						    u8 opt, u8 *val, u8 len);
 	int		(*ccid_hc_tx_send_packet)(struct sock *sk,
 						  struct sk_buff *skb);
 	void		(*ccid_hc_tx_packet_sent)(struct sock *sk,
-						  int more, unsigned int len);
+						  unsigned int len);
 	void		(*ccid_hc_rx_get_info)(struct sock *sk,
 					       struct tcp_info *info);
 	void		(*ccid_hc_tx_get_info)(struct sock *sk,
@@ -148,10 +144,10 @@ static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
 }
 
 static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
-					  int more, unsigned int len)
+					  unsigned int len)
 {
 	if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
-		ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, more, len);
+		ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, len);
 }
 
 static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
@@ -168,27 +164,31 @@ static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
 		ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
 }
 
+/**
+ * ccid_hc_tx_parse_options  -  Parse CCID-specific options sent by the receiver
+ * @pkt: type of packet that @opt appears on (RFC 4340, 5.1)
+ * @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3)
+ * @val: value of @opt
+ * @len: length of @val in bytes
+ */
 static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
-					   unsigned char option,
-					   unsigned char len, u16 idx,
-					   unsigned char* value)
+					   u8 pkt, u8 opt, u8 *val, u8 len)
 {
-	int rc = 0;
-	if (ccid->ccid_ops->ccid_hc_tx_parse_options != NULL)
-		rc = ccid->ccid_ops->ccid_hc_tx_parse_options(sk, option, len, idx,
-						    value);
-	return rc;
+	if (ccid->ccid_ops->ccid_hc_tx_parse_options == NULL)
+		return 0;
+	return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len);
 }
 
+/**
+ * ccid_hc_rx_parse_options  -  Parse CCID-specific options sent by the sender
+ * Arguments are analogous to ccid_hc_tx_parse_options()
+ */
 static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
-					   unsigned char option,
-					   unsigned char len, u16 idx,
-					   unsigned char* value)
+					   u8 pkt, u8 opt, u8 *val, u8 len)
 {
-	int rc = 0;
-	if (ccid->ccid_ops->ccid_hc_rx_parse_options != NULL)
-		rc = ccid->ccid_ops->ccid_hc_rx_parse_options(sk, option, len, idx, value);
-	return rc;
+	if (ccid->ccid_ops->ccid_hc_rx_parse_options == NULL)
+		return 0;
+	return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len);
 }
 
 static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
index 8408398cd44..0581143cb80 100644
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
@@ -47,37 +47,6 @@ config IP_DCCP_CCID3_DEBUG
 
 	  If in doubt, say N.
 
-config IP_DCCP_CCID3_RTO
-	  int "Use higher bound for nofeedback timer"
-	  default 100
-	  depends on IP_DCCP_CCID3 && EXPERIMENTAL
-	  ---help---
-	    Use higher lower bound for nofeedback timer expiration.
-
-	    The TFRC nofeedback timer normally expires after the maximum of 4
-	    RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
-	    with a small RTT this can mean a high processing load and reduced
-	    performance, since then the nofeedback timer is triggered very
-	    frequently.
-
-	    This option enables to set a higher lower bound for the nofeedback
-	    value. Values in units of milliseconds can be set here.
-
-	    A value of 0 disables this feature by enforcing the value specified
-	    in RFC 3448. The following values have been suggested as bounds for
-	    experimental use:
-		* 16-20ms to match the typical multimedia inter-frame interval
-		* 100ms as a reasonable compromise [default]
-		* 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
-
-	    The default of 100ms is a compromise between a large value for
-	    efficient DCCP implementations, and a small value to avoid disrupting
-	    the network in times of congestion.
-
-	    The purpose of the nofeedback timer is to slow DCCP down when there
-	    is serious network congestion: experimenting with larger values should
-	    therefore not be performed on WANs.
-
 config IP_DCCP_TFRC_LIB
 	def_bool y if IP_DCCP_CCID3
 
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 9b3ae9922be..d850e291f87 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -25,59 +25,14 @@
  */
 #include <linux/slab.h>
 #include "../feat.h"
-#include "../ccid.h"
-#include "../dccp.h"
 #include "ccid2.h"
 
 
 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
 static int ccid2_debug;
 #define ccid2_pr_debug(format, a...)	DCCP_PR_DEBUG(ccid2_debug, format, ##a)
-
-static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hc)
-{
-	int len = 0;
-	int pipe = 0;
-	struct ccid2_seq *seqp = hc->tx_seqh;
-
-	/* there is data in the chain */
-	if (seqp != hc->tx_seqt) {
-		seqp = seqp->ccid2s_prev;
-		len++;
-		if (!seqp->ccid2s_acked)
-			pipe++;
-
-		while (seqp != hc->tx_seqt) {
-			struct ccid2_seq *prev = seqp->ccid2s_prev;
-
-			len++;
-			if (!prev->ccid2s_acked)
-				pipe++;
-
-			/* packets are sent sequentially */
-			BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq,
-						prev->ccid2s_seq ) >= 0);
-			BUG_ON(time_before(seqp->ccid2s_sent,
-					   prev->ccid2s_sent));
-
-			seqp = prev;
-		}
-	}
-
-	BUG_ON(pipe != hc->tx_pipe);
-	ccid2_pr_debug("len of chain=%d\n", len);
-
-	do {
-		seqp = seqp->ccid2s_prev;
-		len++;
-	} while (seqp != hc->tx_seqh);
-
-	ccid2_pr_debug("total len=%d\n", len);
-	BUG_ON(len != hc->tx_seqbufc * CCID2_SEQBUF_LEN);
-}
 #else
 #define ccid2_pr_debug(format, a...)
-#define ccid2_hc_tx_check_sanity(hc)
 #endif
 
 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
@@ -156,19 +111,10 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
 	dp->dccps_l_ack_ratio = val;
 }
 
-static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hc, long val)
-{
-	ccid2_pr_debug("change SRTT to %ld\n", val);
-	hc->tx_srtt = val;
-}
-
-static void ccid2_start_rto_timer(struct sock *sk);
-
 static void ccid2_hc_tx_rto_expire(unsigned long data)
 {
 	struct sock *sk = (struct sock *)data;
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-	long s;
 
 	bh_lock_sock(sk);
 	if (sock_owned_by_user(sk)) {
@@ -178,23 +124,19 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
 
 	ccid2_pr_debug("RTO_EXPIRE\n");
 
-	ccid2_hc_tx_check_sanity(hc);
-
 	/* back-off timer */
 	hc->tx_rto <<= 1;
+	if (hc->tx_rto > DCCP_RTO_MAX)
+		hc->tx_rto = DCCP_RTO_MAX;
 
-	s = hc->tx_rto / HZ;
-	if (s > 60)
-		hc->tx_rto = 60 * HZ;
-
-	ccid2_start_rto_timer(sk);
+	sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
 
 	/* adjust pipe, cwnd etc */
 	hc->tx_ssthresh = hc->tx_cwnd / 2;
 	if (hc->tx_ssthresh < 2)
 		hc->tx_ssthresh = 2;
-	hc->tx_cwnd	 = 1;
-	hc->tx_pipe	 = 0;
+	hc->tx_cwnd	= 1;
+	hc->tx_pipe	= 0;
 
 	/* clear state about stuff we sent */
 	hc->tx_seqt = hc->tx_seqh;
@@ -204,23 +146,12 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
 	hc->tx_rpseq    = 0;
 	hc->tx_rpdupack = -1;
 	ccid2_change_l_ack_ratio(sk, 1);
-	ccid2_hc_tx_check_sanity(hc);
 out:
 	bh_unlock_sock(sk);
 	sock_put(sk);
 }
 
-static void ccid2_start_rto_timer(struct sock *sk)
-{
-	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-
-	ccid2_pr_debug("setting RTO timeout=%ld\n", hc->tx_rto);
-
-	BUG_ON(timer_pending(&hc->tx_rtotimer));
-	sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
-}
-
-static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
+static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
@@ -230,7 +161,7 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
 
 	hc->tx_seqh->ccid2s_seq   = dp->dccps_gss;
 	hc->tx_seqh->ccid2s_acked = 0;
-	hc->tx_seqh->ccid2s_sent  = jiffies;
+	hc->tx_seqh->ccid2s_sent  = ccid2_time_stamp;
 
 	next = hc->tx_seqh->ccid2s_next;
 	/* check if we need to alloc more space */
@@ -296,23 +227,20 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
 	}
 #endif
 
-	/* setup RTO timer */
-	if (!timer_pending(&hc->tx_rtotimer))
-		ccid2_start_rto_timer(sk);
+	sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
 
 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
 	do {
 		struct ccid2_seq *seqp = hc->tx_seqt;
 
 		while (seqp != hc->tx_seqh) {
-			ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
+			ccid2_pr_debug("out seq=%llu acked=%d time=%u\n",
 				       (unsigned long long)seqp->ccid2s_seq,
 				       seqp->ccid2s_acked, seqp->ccid2s_sent);
 			seqp = seqp->ccid2s_next;
 		}
 	} while (0);
 	ccid2_pr_debug("=========\n");
-	ccid2_hc_tx_check_sanity(hc);
 #endif
 }
 
@@ -378,17 +306,87 @@ out_invalid_option:
 	return -1;
 }
 
-static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
+/**
+ * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm
+ * This code is almost identical with TCP's tcp_rtt_estimator(), since
+ * - it has a higher sampling frequency (recommended by RFC 1323),
+ * - the RTO does not collapse into RTT due to RTTVAR going towards zero,
+ * - it is simple (cf. more complex proposals such as Eifel timer or research
+ *   which suggests that the gain should be set according to window size),
+ * - in tests it was found to work well with CCID2 [gerrit].
+ */
+static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
 {
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+	long m = mrtt ? : 1;
 
-	sk_stop_timer(sk, &hc->tx_rtotimer);
-	ccid2_pr_debug("deleted RTO timer\n");
+	if (hc->tx_srtt == 0) {
+		/* First measurement m */
+		hc->tx_srtt = m << 3;
+		hc->tx_mdev = m << 1;
+
+		hc->tx_mdev_max = max(hc->tx_mdev, tcp_rto_min(sk));
+		hc->tx_rttvar   = hc->tx_mdev_max;
+
+		hc->tx_rtt_seq  = dccp_sk(sk)->dccps_gss;
+	} else {
+		/* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
+		m -= (hc->tx_srtt >> 3);
+		hc->tx_srtt += m;
+
+		/* Similarly, update scaled mdev with regard to |m| */
+		if (m < 0) {
+			m = -m;
+			m -= (hc->tx_mdev >> 2);
+			/*
+			 * This neutralises RTO increase when RTT < SRTT - mdev
+			 * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
+			 * in Linux TCP", USENIX 2002, pp. 49-62).
+			 */
+			if (m > 0)
+				m >>= 3;
+		} else {
+			m -= (hc->tx_mdev >> 2);
+		}
+		hc->tx_mdev += m;
+
+		if (hc->tx_mdev > hc->tx_mdev_max) {
+			hc->tx_mdev_max = hc->tx_mdev;
+			if (hc->tx_mdev_max > hc->tx_rttvar)
+				hc->tx_rttvar = hc->tx_mdev_max;
+		}
+
+		/*
+		 * Decay RTTVAR at most once per flight, exploiting that
+		 *  1) pipe <= cwnd <= Sequence_Window = W  (RFC 4340, 7.5.2)
+		 *  2) AWL = GSS-W+1 <= GAR <= GSS          (RFC 4340, 7.5.1)
+		 * GAR is a useful bound for FlightSize = pipe.
+		 * AWL is probably too low here, as it over-estimates pipe.
+		 */
+		if (after48(dccp_sk(sk)->dccps_gar, hc->tx_rtt_seq)) {
+			if (hc->tx_mdev_max < hc->tx_rttvar)
+				hc->tx_rttvar -= (hc->tx_rttvar -
+						  hc->tx_mdev_max) >> 2;
+			hc->tx_rtt_seq  = dccp_sk(sk)->dccps_gss;
+			hc->tx_mdev_max = tcp_rto_min(sk);
+		}
+	}
+
+	/*
+	 * Set RTO from SRTT and RTTVAR
+	 * As in TCP, 4 * RTTVAR >= TCP_RTO_MIN, giving a minimum RTO of 200 ms.
+	 * This agrees with RFC 4341, 5:
+	 *	"Because DCCP does not retransmit data, DCCP does not require
+	 *	 TCP's recommended minimum timeout of one second".
+	 */
+	hc->tx_rto = (hc->tx_srtt >> 3) + hc->tx_rttvar;
+
+	if (hc->tx_rto > DCCP_RTO_MAX)
+		hc->tx_rto = DCCP_RTO_MAX;
 }
 
-static inline void ccid2_new_ack(struct sock *sk,
-				 struct ccid2_seq *seqp,
-				 unsigned int *maxincr)
+static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp,
+			  unsigned int *maxincr)
 {
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
 
@@ -402,93 +400,27 @@ static inline void ccid2_new_ack(struct sock *sk,
 			hc->tx_cwnd += 1;
 			hc->tx_packets_acked = 0;
 	}
-
-	/* update RTO */
-	if (hc->tx_srtt == -1 ||
-	    time_after(jiffies, hc->tx_lastrtt + hc->tx_srtt)) {
-		unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
-		int s;
-
-		/* first measurement */
-		if (hc->tx_srtt == -1) {
-			ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
-				       r, jiffies,
-				       (unsigned long long)seqp->ccid2s_seq);
-			ccid2_change_srtt(hc, r);
-			hc->tx_rttvar = r >> 1;
-		} else {
-			/* RTTVAR */
-			long tmp = hc->tx_srtt - r;
-			long srtt;
-
-			if (tmp < 0)
-				tmp *= -1;
-
-			tmp >>= 2;
-			hc->tx_rttvar *= 3;
-			hc->tx_rttvar >>= 2;
-			hc->tx_rttvar += tmp;
-
-			/* SRTT */
-			srtt = hc->tx_srtt;
-			srtt *= 7;
-			srtt >>= 3;
-			tmp = r >> 3;
-			srtt += tmp;
-			ccid2_change_srtt(hc, srtt);
-		}
-		s = hc->tx_rttvar << 2;
-		/* clock granularity is 1 when based on jiffies */
-		if (!s)
-			s = 1;
-		hc->tx_rto = hc->tx_srtt + s;
-
-		/* must be at least a second */
-		s = hc->tx_rto / HZ;
-		/* DCCP doesn't require this [but I like it cuz my code sux] */
-#if 1
-		if (s < 1)
-			hc->tx_rto = HZ;
-#endif
-		/* max 60 seconds */
-		if (s > 60)
-			hc->tx_rto = HZ * 60;
-
-		hc->tx_lastrtt = jiffies;
-
-		ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
-			       hc->tx_srtt, hc->tx_rttvar,
-			       hc->tx_rto, HZ, r);
-	}
-
-	/* we got a new ack, so re-start RTO timer */
-	ccid2_hc_tx_kill_rto_timer(sk);
-	ccid2_start_rto_timer(sk);
-}
-
-static void ccid2_hc_tx_dec_pipe(struct sock *sk)
-{
-	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-
-	if (hc->tx_pipe == 0)
-		DCCP_BUG("pipe == 0");
-	else
-		hc->tx_pipe--;
-
-	if (hc->tx_pipe == 0)
-		ccid2_hc_tx_kill_rto_timer(sk);
+	/*
+	 * FIXME: RTT is sampled several times per acknowledgment (for each
+	 * entry in the Ack Vector), instead of once per Ack (as in TCP SACK).
+	 * This causes the RTT to be over-estimated, since the older entries
+	 * in the Ack Vector have earlier sending times.
+	 * The cleanest solution is to not use the ccid2s_sent field at all
+	 * and instead use DCCP timestamps: requires changes in other places.
+	 */
+	ccid2_rtt_estimator(sk, ccid2_time_stamp - seqp->ccid2s_sent);
 }
 
 static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
 {
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
 
-	if (time_before(seqp->ccid2s_sent, hc->tx_last_cong)) {
+	if ((s32)(seqp->ccid2s_sent - hc->tx_last_cong) < 0) {
 		ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
 		return;
 	}
 
-	hc->tx_last_cong = jiffies;
+	hc->tx_last_cong = ccid2_time_stamp;
 
 	hc->tx_cwnd      = hc->tx_cwnd / 2 ? : 1U;
 	hc->tx_ssthresh  = max(hc->tx_cwnd, 2U);
@@ -510,7 +442,6 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	int done = 0;
 	unsigned int maxincr = 0;
 
-	ccid2_hc_tx_check_sanity(hc);
 	/* check reverse path congestion */
 	seqno = DCCP_SKB_CB(skb)->dccpd_seq;
 
@@ -620,7 +551,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 					seqp->ccid2s_acked = 1;
 					ccid2_pr_debug("Got ack for %llu\n",
 						       (unsigned long long)seqp->ccid2s_seq);
-					ccid2_hc_tx_dec_pipe(sk);
+					hc->tx_pipe--;
 				}
 				if (seqp == hc->tx_seqt) {
 					done = 1;
@@ -677,7 +608,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 				 * one ack vector.
 				 */
 				ccid2_congestion_event(sk, seqp);
-				ccid2_hc_tx_dec_pipe(sk);
+				hc->tx_pipe--;
 			}
 			if (seqp == hc->tx_seqt)
 				break;
@@ -695,7 +626,11 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 		hc->tx_seqt = hc->tx_seqt->ccid2s_next;
 	}
 
-	ccid2_hc_tx_check_sanity(hc);
+	/* restart RTO timer if not all outstanding data has been acked */
+	if (hc->tx_pipe == 0)
+		sk_stop_timer(sk, &hc->tx_rtotimer);
+	else
+		sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
 }
 
 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -707,12 +642,8 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
 	/* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
 	hc->tx_ssthresh = ~0U;
 
-	/*
-	 * RFC 4341, 5: "The cwnd parameter is initialized to at most four
-	 * packets for new connections, following the rules from [RFC3390]".
-	 * We need to convert the bytes of RFC3390 into the packets of RFC 4341.
-	 */
-	hc->tx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U);
+	/* Use larger initial windows (RFC 4341, section 5). */
+	hc->tx_cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache);
 
 	/* Make sure that Ack Ratio is enabled and within bounds. */
 	max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2);
@@ -723,15 +654,11 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
 	if (ccid2_hc_tx_alloc_seq(hc))
 		return -ENOMEM;
 
-	hc->tx_rto	 = 3 * HZ;
-	ccid2_change_srtt(hc, -1);
-	hc->tx_rttvar    = -1;
+	hc->tx_rto	 = DCCP_TIMEOUT_INIT;
 	hc->tx_rpdupack  = -1;
-	hc->tx_last_cong = jiffies;
+	hc->tx_last_cong = ccid2_time_stamp;
 	setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire,
 			(unsigned long)sk);
-
-	ccid2_hc_tx_check_sanity(hc);
 	return 0;
 }
 
@@ -740,7 +667,7 @@ static void ccid2_hc_tx_exit(struct sock *sk)
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
 	int i;
 
-	ccid2_hc_tx_kill_rto_timer(sk);
+	sk_stop_timer(sk, &hc->tx_rtotimer);
 
 	for (i = 0; i < hc->tx_seqbufc; i++)
 		kfree(hc->tx_seqbuf[i]);
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 1ec6a30103b..9731c2dc148 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -18,18 +18,23 @@
 #ifndef _DCCP_CCID2_H_
 #define _DCCP_CCID2_H_
 
-#include <linux/dccp.h>
 #include <linux/timer.h>
 #include <linux/types.h>
 #include "../ccid.h"
+#include "../dccp.h"
+
+/*
+ * CCID-2 timestamping faces the same issues as TCP timestamping.
+ * Hence we reuse/share as much of the code as possible.
+ */
+#define ccid2_time_stamp	tcp_time_stamp
+
 /* NUMDUPACK parameter from RFC 4341, p. 6 */
 #define NUMDUPACK	3
 
-struct sock;
-
 struct ccid2_seq {
 	u64			ccid2s_seq;
-	unsigned long		ccid2s_sent;
+	u32			ccid2s_sent;
 	int			ccid2s_acked;
 	struct ccid2_seq	*ccid2s_prev;
 	struct ccid2_seq	*ccid2s_next;
@@ -42,7 +47,12 @@ struct ccid2_seq {
  * struct ccid2_hc_tx_sock - CCID2 TX half connection
  * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
  * @tx_packets_acked:	     Ack counter for deriving cwnd growth (RFC 3465)
- * @tx_lastrtt:		     time RTT was last measured
+ * @tx_srtt:		     smoothed RTT estimate, scaled by 2^3
+ * @tx_mdev:		     smoothed RTT variation, scaled by 2^2
+ * @tx_mdev_max:	     maximum of @mdev during one flight
+ * @tx_rttvar:		     moving average/maximum of @mdev_max
+ * @tx_rto:		     RTO value deriving from SRTT and RTTVAR (RFC 2988)
+ * @tx_rtt_seq:		     to decay RTTVAR at most once per flight
  * @tx_rpseq:		     last consecutive seqno
  * @tx_rpdupack:	     dupacks since rpseq
  */
@@ -55,14 +65,19 @@ struct ccid2_hc_tx_sock {
 	int			tx_seqbufc;
 	struct ccid2_seq	*tx_seqh;
 	struct ccid2_seq	*tx_seqt;
-	long			tx_rto;
-	long			tx_srtt;
-	long			tx_rttvar;
-	unsigned long		tx_lastrtt;
+
+	/* RTT measurement: variables/principles are the same as in TCP */
+	u32			tx_srtt,
+				tx_mdev,
+				tx_mdev_max,
+				tx_rttvar,
+				tx_rto;
+	u64			tx_rtt_seq:48;
 	struct timer_list	tx_rtotimer;
+
 	u64			tx_rpseq;
 	int			tx_rpdupack;
-	unsigned long		tx_last_cong;
+	u32			tx_last_cong;
 	u64			tx_high_ack;
 };
 
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 95f75298649..3060a60ed5a 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -54,7 +54,6 @@ static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
 	[TFRC_SSTATE_NO_SENT]  = "NO_SENT",
 	[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
 	[TFRC_SSTATE_FBACK]    = "FBACK",
-	[TFRC_SSTATE_TERM]     = "TERM",
 	};
 
 	return ccid3_state_names[state];
@@ -91,19 +90,16 @@ static inline u64 rfc3390_initial_rate(struct sock *sk)
 	return scaled_div(w_init << 6, hc->tx_rtt);
 }
 
-/*
- * Recalculate t_ipi and delta (should be called whenever X changes)
+/**
+ * ccid3_update_send_interval  -  Calculate new t_ipi = s / X_inst
+ * This respects the granularity of X_inst (64 * bytes/second).
  */
 static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
 {
-	/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
 	hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
 
-	/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
-	hc->tx_delta = min_t(u32, hc->tx_t_ipi / 2, TFRC_OPSYS_HALF_TIME_GRAN);
-
-	ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n", hc->tx_t_ipi,
-		       hc->tx_delta, hc->tx_s, (unsigned)(hc->tx_x >> 6));
+	ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
+		       hc->tx_s, (unsigned)(hc->tx_x >> 6));
 }
 
 static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
@@ -211,16 +207,19 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
 	ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
 		       ccid3_tx_state_name(hc->tx_state));
 
+	/* Ignore and do not restart after leaving the established state */
+	if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
+		goto out;
+
+	/* Reset feedback state to "no feedback received" */
 	if (hc->tx_state == TFRC_SSTATE_FBACK)
 		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
-	else if (hc->tx_state != TFRC_SSTATE_NO_FBACK)
-		goto out;
 
 	/*
 	 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
+	 * RTO is 0 if and only if no feedback has been received yet.
 	 */
-	if (hc->tx_t_rto == 0 ||	/* no feedback received yet */
-	    hc->tx_p == 0) {
+	if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
 
 		/* halve send rate directly */
 		hc->tx_x = max(hc->tx_x / 2,
@@ -256,7 +255,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
 	 * Set new timeout for the nofeedback timer.
 	 * See comments in packet_recv() regarding the value of t_RTO.
 	 */
-	if (unlikely(hc->tx_t_rto == 0))	/* no feedback yet */
+	if (unlikely(hc->tx_t_rto == 0))	/* no feedback received yet */
 		t_nfb = TFRC_INITIAL_TIMEOUT;
 	else
 		t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
@@ -290,8 +289,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 	if (unlikely(skb->len == 0))
 		return -EBADMSG;
 
-	switch (hc->tx_state) {
-	case TFRC_SSTATE_NO_SENT:
+	if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
 		sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
 			       usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
 		hc->tx_last_win_count	= 0;
@@ -326,27 +324,22 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 		ccid3_update_send_interval(hc);
 
 		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
-		break;
-	case TFRC_SSTATE_NO_FBACK:
-	case TFRC_SSTATE_FBACK:
+
+	} else {
 		delay = ktime_us_delta(hc->tx_t_nom, now);
 		ccid3_pr_debug("delay=%ld\n", (long)delay);
 		/*
-		 *	Scheduling of packet transmissions [RFC 3448, 4.6]
+		 *	Scheduling of packet transmissions (RFC 5348, 8.3)
 		 *
 		 * if (t_now > t_nom - delta)
 		 *       // send the packet now
 		 * else
 		 *       // send the packet in (t_nom - t_now) milliseconds.
 		 */
-		if (delay - (s64)hc->tx_delta >= 1000)
-			return (u32)delay / 1000L;
+		if (delay >= TFRC_T_DELTA)
+			return (u32)delay / USEC_PER_MSEC;
 
 		ccid3_hc_tx_update_win_count(hc, now);
-		break;
-	case TFRC_SSTATE_TERM:
-		DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
-		return -EINVAL;
 	}
 
 	/* prepare to send now (add options etc.) */
@@ -358,8 +351,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 	return 0;
 }
 
-static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
-				    unsigned int len)
+static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
 {
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
 
@@ -372,48 +364,34 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 {
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
-	struct ccid3_options_received *opt_recv;
+	struct tfrc_tx_hist_entry *acked;
 	ktime_t now;
 	unsigned long t_nfb;
-	u32 pinv, r_sample;
+	u32 r_sample;
 
 	/* we are only interested in ACKs */
 	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
 	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
 		return;
-	/* ... and only in the established state */
-	if (hc->tx_state != TFRC_SSTATE_FBACK &&
-	    hc->tx_state != TFRC_SSTATE_NO_FBACK)
-		return;
-
-	opt_recv = &hc->tx_options_received;
-	now = ktime_get_real();
-
-	/* Estimate RTT from history if ACK number is valid */
-	r_sample = tfrc_tx_hist_rtt(hc->tx_hist,
-				    DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
-	if (r_sample == 0) {
-		DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
-			  dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
-			  (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
-		return;
-	}
-
-	/* Update receive rate in units of 64 * bytes/second */
-	hc->tx_x_recv = opt_recv->ccid3or_receive_rate;
-	hc->tx_x_recv <<= 6;
-
-	/* Update loss event rate (which is scaled by 1e6) */
-	pinv = opt_recv->ccid3or_loss_event_rate;
-	if (pinv == ~0U || pinv == 0)	       /* see RFC 4342, 8.5   */
-		hc->tx_p = 0;
-	else				       /* can not exceed 100% */
-		hc->tx_p = scaled_div(1, pinv);
 	/*
-	 * Validate new RTT sample and update moving average
+	 * Locate the acknowledged packet in the TX history.
+	 *
+	 * Returning "entry not found" here can for instance happen when
+	 *  - the host has not sent out anything (e.g. a passive server),
+	 *  - the Ack is outdated (packet with higher Ack number was received),
+	 *  - it is a bogus Ack (for a packet not sent on this connection).
 	 */
-	r_sample = dccp_sample_rtt(sk, r_sample);
+	acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
+	if (acked == NULL)
+		return;
+	/* For the sake of RTT sampling, ignore/remove all older entries */
+	tfrc_tx_hist_purge(&acked->next);
+
+	/* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
+	now	  = ktime_get_real();
+	r_sample  = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
 	hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
+
 	/*
 	 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
 	 */
@@ -461,13 +439,12 @@ done_computing_x:
 	sk->sk_write_space(sk);
 
 	/*
-	 * Update timeout interval for the nofeedback timer.
-	 * We use a configuration option to increase the lower bound.
-	 * This can help avoid triggering the nofeedback timer too
-	 * often ('spinning') on LANs with small RTTs.
+	 * Update timeout interval for the nofeedback timer. In order to control
+	 * rate halving on networks with very low RTTs (<= 1 ms), use per-route
+	 * tunable RTAX_RTO_MIN value as the lower bound.
 	 */
-	hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, (CONFIG_IP_DCCP_CCID3_RTO *
-						       (USEC_PER_SEC / 1000)));
+	hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
+				  USEC_PER_SEC/HZ * tcp_rto_min(sk));
 	/*
 	 * Schedule no feedback timer to expire in
 	 * max(t_RTO, 2 * s/X)  =  max(t_RTO, 2 * t_ipi)
@@ -482,66 +459,41 @@ done_computing_x:
 			   jiffies + usecs_to_jiffies(t_nfb));
 }
 
-static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
-				     unsigned char len, u16 idx,
-				     unsigned char *value)
+static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+				     u8 option, u8 *optval, u8 optlen)
 {
-	int rc = 0;
-	const struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
-	struct ccid3_options_received *opt_recv;
 	__be32 opt_val;
 
-	opt_recv = &hc->tx_options_received;
-
-	if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
-		opt_recv->ccid3or_seqno		     = dp->dccps_gsr;
-		opt_recv->ccid3or_loss_event_rate    = ~0;
-		opt_recv->ccid3or_loss_intervals_idx = 0;
-		opt_recv->ccid3or_loss_intervals_len = 0;
-		opt_recv->ccid3or_receive_rate	     = 0;
-	}
-
 	switch (option) {
+	case TFRC_OPT_RECEIVE_RATE:
 	case TFRC_OPT_LOSS_EVENT_RATE:
-		if (unlikely(len != 4)) {
-			DCCP_WARN("%s(%p), invalid len %d "
-				  "for TFRC_OPT_LOSS_EVENT_RATE\n",
-				  dccp_role(sk), sk, len);
-			rc = -EINVAL;
-		} else {
-			opt_val = get_unaligned((__be32 *)value);
-			opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
-			ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
-				       dccp_role(sk), sk,
-				       opt_recv->ccid3or_loss_event_rate);
+		/* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
+		if (packet_type == DCCP_PKT_DATA)
+			break;
+		if (unlikely(optlen != 4)) {
+			DCCP_WARN("%s(%p), invalid len %d for %u\n",
+				  dccp_role(sk), sk, optlen, option);
+			return -EINVAL;
 		}
-		break;
-	case TFRC_OPT_LOSS_INTERVALS:
-		opt_recv->ccid3or_loss_intervals_idx = idx;
-		opt_recv->ccid3or_loss_intervals_len = len;
-		ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
-			       dccp_role(sk), sk,
-			       opt_recv->ccid3or_loss_intervals_idx,
-			       opt_recv->ccid3or_loss_intervals_len);
-		break;
-	case TFRC_OPT_RECEIVE_RATE:
-		if (unlikely(len != 4)) {
-			DCCP_WARN("%s(%p), invalid len %d "
-				  "for TFRC_OPT_RECEIVE_RATE\n",
-				  dccp_role(sk), sk, len);
-			rc = -EINVAL;
-		} else {
-			opt_val = get_unaligned((__be32 *)value);
-			opt_recv->ccid3or_receive_rate = ntohl(opt_val);
+		opt_val = ntohl(get_unaligned((__be32 *)optval));
+
+		if (option == TFRC_OPT_RECEIVE_RATE) {
+			/* Receive Rate is kept in units of 64 bytes/second */
+			hc->tx_x_recv = opt_val;
+			hc->tx_x_recv <<= 6;
+
 			ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
-				       dccp_role(sk), sk,
-				       opt_recv->ccid3or_receive_rate);
+				       dccp_role(sk), sk, opt_val);
+		} else {
+			/* Update the fixpoint Loss Event Rate fraction */
+			hc->tx_p = tfrc_invert_loss_event_rate(opt_val);
+
+			ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
+				       dccp_role(sk), sk, opt_val);
 		}
-		break;
 	}
-
-	return rc;
+	return 0;
 }
 
 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -559,42 +511,36 @@ static void ccid3_hc_tx_exit(struct sock *sk)
 {
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
 
-	ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
 	sk_stop_timer(sk, &hc->tx_no_feedback_timer);
-
 	tfrc_tx_hist_purge(&hc->tx_hist);
 }
 
 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
 {
-	struct ccid3_hc_tx_sock *hc;
-
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return;
-
-	hc = ccid3_hc_tx_sk(sk);
-	info->tcpi_rto = hc->tx_t_rto;
-	info->tcpi_rtt = hc->tx_rtt;
+	info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
+	info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
 }
 
 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
 				  u32 __user *optval, int __user *optlen)
 {
-	const struct ccid3_hc_tx_sock *hc;
+	const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
+	struct tfrc_tx_info tfrc;
 	const void *val;
 
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return -EINVAL;
-
-	hc = ccid3_hc_tx_sk(sk);
 	switch (optname) {
 	case DCCP_SOCKOPT_CCID_TX_INFO:
-		if (len < sizeof(hc->tx_tfrc))
+		if (len < sizeof(tfrc))
 			return -EINVAL;
-		len = sizeof(hc->tx_tfrc);
-		val = &hc->tx_tfrc;
+		tfrc.tfrctx_x	   = hc->tx_x;
+		tfrc.tfrctx_x_recv = hc->tx_x_recv;
+		tfrc.tfrctx_x_calc = hc->tx_x_calc;
+		tfrc.tfrctx_rtt	   = hc->tx_rtt;
+		tfrc.tfrctx_p	   = hc->tx_p;
+		tfrc.tfrctx_rto	   = hc->tx_t_rto;
+		tfrc.tfrctx_ipi	   = hc->tx_t_ipi;
+		len = sizeof(tfrc);
+		val = &tfrc;
 		break;
 	default:
 		return -ENOPROTOOPT;
@@ -624,7 +570,6 @@ static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
 	static const char *const ccid3_rx_state_names[] = {
 	[TFRC_RSTATE_NO_DATA] = "NO_DATA",
 	[TFRC_RSTATE_DATA]    = "DATA",
-	[TFRC_RSTATE_TERM]    = "TERM",
 	};
 
 	return ccid3_rx_state_names[state];
@@ -650,14 +595,9 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
 {
 	struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 	struct dccp_sock *dp = dccp_sk(sk);
-	ktime_t now;
+	ktime_t now = ktime_get_real();
 	s64 delta = 0;
 
-	if (unlikely(hc->rx_state == TFRC_RSTATE_TERM))
-		return;
-
-	now = ktime_get_real();
-
 	switch (fbtype) {
 	case CCID3_FBACK_INITIAL:
 		hc->rx_x_recv = 0;
@@ -701,14 +641,12 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
 
 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
 {
-	const struct ccid3_hc_rx_sock *hc;
+	const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 	__be32 x_recv, pinv;
 
 	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
 		return 0;
 
-	hc = ccid3_hc_rx_sk(sk);
-
 	if (dccp_packet_without_ack(skb))
 		return 0;
 
@@ -749,10 +687,11 @@ static u32 ccid3_first_li(struct sock *sk)
 	x_recv = scaled_div32(hc->rx_bytes_recv, delta);
 	if (x_recv == 0) {		/* would also trigger divide-by-zero */
 		DCCP_WARN("X_recv==0\n");
-		if ((x_recv = hc->rx_x_recv) == 0) {
+		if (hc->rx_x_recv == 0) {
 			DCCP_BUG("stored value of X_recv is zero");
 			return ~0U;
 		}
+		x_recv = hc->rx_x_recv;
 	}
 
 	fval = scaled_div(hc->rx_s, hc->rx_rtt);
@@ -862,46 +801,31 @@ static void ccid3_hc_rx_exit(struct sock *sk)
 {
 	struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 
-	ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
-
 	tfrc_rx_hist_purge(&hc->rx_hist);
 	tfrc_lh_cleanup(&hc->rx_li_hist);
 }
 
 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
 {
-	const struct ccid3_hc_rx_sock *hc;
-
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return;
-
-	hc = ccid3_hc_rx_sk(sk);
-	info->tcpi_ca_state = hc->rx_state;
+	info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
 	info->tcpi_options  |= TCPI_OPT_TIMESTAMPS;
-	info->tcpi_rcv_rtt  = hc->rx_rtt;
+	info->tcpi_rcv_rtt  = ccid3_hc_rx_sk(sk)->rx_rtt;
 }
 
 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
 				  u32 __user *optval, int __user *optlen)
 {
-	const struct ccid3_hc_rx_sock *hc;
+	const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 	struct tfrc_rx_info rx_info;
 	const void *val;
 
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return -EINVAL;
-
-	hc = ccid3_hc_rx_sk(sk);
 	switch (optname) {
 	case DCCP_SOCKOPT_CCID_RX_INFO:
 		if (len < sizeof(rx_info))
 			return -EINVAL;
 		rx_info.tfrcrx_x_recv = hc->rx_x_recv;
 		rx_info.tfrcrx_rtt    = hc->rx_rtt;
-		rx_info.tfrcrx_p      = hc->rx_pinv == 0 ? ~0U :
-					   scaled_div(1, hc->rx_pinv);
+		rx_info.tfrcrx_p      = tfrc_invert_loss_event_rate(hc->rx_pinv);
 		len = sizeof(rx_info);
 		val = &rx_info;
 		break;
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 03263577665..1a9933c2967 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -42,35 +42,36 @@
 #include "lib/tfrc.h"
 #include "../ccid.h"
 
-/* Two seconds as per RFC 3448 4.2 */
+/* Two seconds as per RFC 5348, 4.2 */
 #define TFRC_INITIAL_TIMEOUT	   (2 * USEC_PER_SEC)
 
-/* In usecs - half the scheduling granularity as per RFC3448 4.6 */
-#define TFRC_OPSYS_HALF_TIME_GRAN  (USEC_PER_SEC / (2 * HZ))
-
 /* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
 #define TFRC_T_MBI		   64
 
+/*
+ * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
+ * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
+ * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
+ * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
+ * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
+ */
+#if (HZ >= 500)
+# define TFRC_T_DELTA		   USEC_PER_MSEC
+#else
+# define TFRC_T_DELTA		   (USEC_PER_SEC / (2 * HZ))
+#endif
+
 enum ccid3_options {
 	TFRC_OPT_LOSS_EVENT_RATE = 192,
 	TFRC_OPT_LOSS_INTERVALS	 = 193,
 	TFRC_OPT_RECEIVE_RATE	 = 194,
 };
 
-struct ccid3_options_received {
-	u64 ccid3or_seqno:48,
-	    ccid3or_loss_intervals_idx:16;
-	u16 ccid3or_loss_intervals_len;
-	u32 ccid3or_loss_event_rate;
-	u32 ccid3or_receive_rate;
-};
-
 /* TFRC sender states */
 enum ccid3_hc_tx_states {
 	TFRC_SSTATE_NO_SENT = 1,
 	TFRC_SSTATE_NO_FBACK,
 	TFRC_SSTATE_FBACK,
-	TFRC_SSTATE_TERM,
 };
 
 /**
@@ -90,19 +91,16 @@ enum ccid3_hc_tx_states {
  * @tx_no_feedback_timer: Handle to no feedback timer
  * @tx_t_ld:		  Time last doubled during slow start
  * @tx_t_nom:		  Nominal send time of next packet
- * @tx_delta:		  Send timer delta (RFC 3448, 4.6) in usecs
  * @tx_hist:		  Packet history
- * @tx_options_received:  Parsed set of retrieved options
  */
 struct ccid3_hc_tx_sock {
-	struct tfrc_tx_info		tx_tfrc;
-#define tx_x				tx_tfrc.tfrctx_x
-#define tx_x_recv			tx_tfrc.tfrctx_x_recv
-#define tx_x_calc			tx_tfrc.tfrctx_x_calc
-#define tx_rtt				tx_tfrc.tfrctx_rtt
-#define tx_p				tx_tfrc.tfrctx_p
-#define tx_t_rto			tx_tfrc.tfrctx_rto
-#define tx_t_ipi			tx_tfrc.tfrctx_ipi
+	u64				tx_x;
+	u64				tx_x_recv;
+	u32				tx_x_calc;
+	u32				tx_rtt;
+	u32				tx_p;
+	u32				tx_t_rto;
+	u32				tx_t_ipi;
 	u16				tx_s;
 	enum ccid3_hc_tx_states		tx_state:8;
 	u8				tx_last_win_count;
@@ -110,9 +108,7 @@ struct ccid3_hc_tx_sock {
 	struct timer_list		tx_no_feedback_timer;
 	ktime_t				tx_t_ld;
 	ktime_t				tx_t_nom;
-	u32				tx_delta;
 	struct tfrc_tx_hist_entry	*tx_hist;
-	struct ccid3_options_received	tx_options_received;
 };
 
 static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
@@ -126,21 +122,16 @@ static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
 enum ccid3_hc_rx_states {
 	TFRC_RSTATE_NO_DATA = 1,
 	TFRC_RSTATE_DATA,
-	TFRC_RSTATE_TERM    = 127,
 };
 
 /**
  * struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
- * @rx_x_recv:		     Receiver estimate of send rate (RFC 3448 4.3)
- * @rx_rtt:		     Receiver estimate of rtt (non-standard)
- * @rx_p:		     Current loss event rate (RFC 3448 5.4)
  * @rx_last_counter:	     Tracks window counter (RFC 4342, 8.1)
  * @rx_state:		     Receiver state, one of %ccid3_hc_rx_states
  * @rx_bytes_recv:	     Total sum of DCCP payload bytes
  * @rx_x_recv:		     Receiver estimate of send rate (RFC 3448, sec. 4.3)
  * @rx_rtt:		     Receiver estimate of RTT
  * @rx_tstamp_last_feedback: Time at which last feedback was sent
- * @rx_tstamp_last_ack:	     Time at which last feedback was sent
  * @rx_hist:		     Packet history (loss detection + RTT sampling)
  * @rx_li_hist:		     Loss Interval database
  * @rx_s:		     Received packet size in bytes
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 8fc3cbf7907..497723c4d4b 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -116,7 +116,7 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
 	cur->li_length = len;
 	tfrc_lh_calc_i_mean(lh);
 
-	return (lh->i_mean < old_i_mean);
+	return lh->i_mean < old_i_mean;
 }
 
 /* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 3a4f414e94a..de8fe294bf0 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -38,18 +38,6 @@
 #include "packet_history.h"
 #include "../../dccp.h"
 
-/**
- *  tfrc_tx_hist_entry  -  Simple singly-linked TX history list
- *  @next:  next oldest entry (LIFO order)
- *  @seqno: sequence number of this entry
- *  @stamp: send time of packet with sequence number @seqno
- */
-struct tfrc_tx_hist_entry {
-	struct tfrc_tx_hist_entry *next;
-	u64			  seqno;
-	ktime_t			  stamp;
-};
-
 /*
  * Transmitter History Routines
  */
@@ -71,15 +59,6 @@ void tfrc_tx_packet_history_exit(void)
 	}
 }
 
-static struct tfrc_tx_hist_entry *
-	tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
-{
-	while (head != NULL && head->seqno != seqno)
-		head = head->next;
-
-	return head;
-}
-
 int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
 {
 	struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
@@ -107,24 +86,6 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
 	*headp = NULL;
 }
 
-u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
-		     const ktime_t now)
-{
-	u32 rtt = 0;
-	struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
-
-	if (packet != NULL) {
-		rtt = ktime_us_delta(now, packet->stamp);
-		/*
-		 * Garbage-collect older (irrelevant) entries:
-		 */
-		tfrc_tx_hist_purge(&packet->next);
-	}
-
-	return rtt;
-}
-
-
 /*
  *	Receiver History Routines
  */
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 7df6c529999..7ee4a9d9d33 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -40,12 +40,28 @@
 #include <linux/slab.h>
 #include "tfrc.h"
 
-struct tfrc_tx_hist_entry;
+/**
+ *  tfrc_tx_hist_entry  -  Simple singly-linked TX history list
+ *  @next:  next oldest entry (LIFO order)
+ *  @seqno: sequence number of this entry
+ *  @stamp: send time of packet with sequence number @seqno
+ */
+struct tfrc_tx_hist_entry {
+	struct tfrc_tx_hist_entry *next;
+	u64			  seqno;
+	ktime_t			  stamp;
+};
+
+static inline struct tfrc_tx_hist_entry *
+	tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
+{
+	while (head != NULL && head->seqno != seqno)
+		head = head->next;
+	return head;
+}
 
 extern int  tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
 extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
-extern u32  tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
-			     const u64 seqno, const ktime_t now);
 
 /* Subtraction a-b modulo-16, respects circular wrap-around */
 #define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index 01bb48e96c2..f8ee3f54977 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -57,6 +57,7 @@ static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
 
 extern u32  tfrc_calc_x(u16 s, u32 R, u32 p);
 extern u32  tfrc_calc_x_reverse_lookup(u32 fvalue);
+extern u32  tfrc_invert_loss_event_rate(u32 loss_event_rate);
 
 extern int  tfrc_tx_packet_history_init(void);
 extern void tfrc_tx_packet_history_exit(void);
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
index 22ca1cf0eb5..a052a4377e2 100644
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -687,3 +687,17 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
 	index = tfrc_binsearch(fvalue, 0);
 	return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE;
 }
+
+/**
+ * tfrc_invert_loss_event_rate  -  Compute p so that 10^6 corresponds to 100%
+ * When @loss_event_rate is large, there is a chance that p is truncated to 0.
+ * To avoid re-entering slow-start in that case, we set p = TFRC_SMALLEST_P > 0.
+ */
+u32 tfrc_invert_loss_event_rate(u32 loss_event_rate)
+{
+	if (loss_event_rate == UINT_MAX)		/* see RFC 4342, 8.5 */
+		return 0;
+	if (unlikely(loss_event_rate == 0))		/* map 1/0 into 100% */
+		return 1000000;
+	return max_t(u32, scaled_div(1, loss_event_rate), TFRC_SMALLEST_P);
+}
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 3ccef1b70fe..3eb264b6082 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -153,18 +153,27 @@ static inline u64 max48(const u64 seq1, const u64 seq2)
 }
 
 /**
- * dccp_loss_free  -  Evaluates condition for data loss from RFC 4340, 7.7.1
- * @s1:	 start sequence number
- * @s2:  end sequence number
+ * dccp_loss_count - Approximate the number of lost data packets in a burst loss
+ * @s1:  last known sequence number before the loss ('hole')
+ * @s2:  first sequence number seen after the 'hole'
  * @ndp: NDP count on packet with sequence number @s2
- * Returns true if the sequence range s1...s2 has no data loss.
  */
-static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
+static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
 {
 	s64 delta = dccp_delta_seqno(s1, s2);
 
 	WARN_ON(delta < 0);
-	return (u64)delta <= ndp + 1;
+	delta -= ndp + 1;
+
+	return delta > 0 ? delta : 0;
+}
+
+/**
+ * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
+ */
+static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
+{
+	return dccp_loss_count(s1, s2, ndp) == 0;
 }
 
 enum {
@@ -246,7 +255,6 @@ static inline void dccp_clear_xmit_timers(struct sock *sk)
 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
 
 extern const char *dccp_packet_name(const int type);
-extern const char *dccp_state_name(const int state);
 
 extern void dccp_set_state(struct sock *sk, const int state);
 extern void dccp_done(struct sock *sk);
@@ -415,6 +423,23 @@ static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 	dp->dccps_gsr = seq;
 	/* Sequence validity window depends on remote Sequence Window (7.5.1) */
 	dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
+	/*
+	 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
+	 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
+	 * always > 32, so for the first W/W' packets in the lifetime of a
+	 * connection we always have to adjust SWL.
+	 * A second reason why we are doing this is that the window depends on
+	 * the feature-remote value of Sequence Window: nothing stops the peer
+	 * from updating this value while we are busy adjusting SWL for the
+	 * first W packets (we would have to count from scratch again then).
+	 * Therefore it is safer to always make sure that the Sequence Window
+	 * is not artificially extended by a peer who grows SWL downwards by
+	 * continually updating the feature-remote Sequence-Window.
+	 * If sequence numbers wrap it is bad luck. But that will take a while
+	 * (48 bit), and this measure prevents Sequence-number attacks.
+	 */
+	if (before48(dp->dccps_swl, dp->dccps_isr))
+		dp->dccps_swl = dp->dccps_isr;
 	dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
 }
 
@@ -425,14 +450,16 @@ static inline void dccp_update_gss(struct sock *sk, u64 seq)
 	dp->dccps_gss = seq;
 	/* Ack validity window depends on local Sequence Window value (7.5.1) */
 	dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
+	/* Adjust AWL so that it is not below ISS - see comment above for SWL */
+	if (before48(dp->dccps_awl, dp->dccps_iss))
+		dp->dccps_awl = dp->dccps_iss;
 	dp->dccps_awh = dp->dccps_gss;
 }
 
 static inline int dccp_ack_pending(const struct sock *sk)
 {
 	const struct dccp_sock *dp = dccp_sk(sk);
-	return dp->dccps_timestamp_echo != 0 ||
-	       (dp->dccps_hc_rx_ackvec != NULL &&
+	return (dp->dccps_hc_rx_ackvec != NULL &&
 		dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
 	       inet_csk_ack_scheduled(sk);
 }
@@ -449,7 +476,6 @@ extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
 extern int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed);
 extern u32 dccp_timestamp(void);
 extern void dccp_timestamping_init(void);
-extern int dccp_insert_option_timestamp(struct sk_buff *skb);
 extern int dccp_insert_option(struct sk_buff *skb, unsigned char option,
 			      const void *value, unsigned char len);
 
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index df7dd26cf07..568def95272 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -730,16 +730,6 @@ int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
 				  0, list, len);
 }
 
-/* Analogous to dccp_feat_register_sp(), but for non-negotiable values */
-int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val)
-{
-	/* any changes must be registered before establishing the connection */
-	if (sk->sk_state != DCCP_CLOSED)
-		return -EISCONN;
-	if (dccp_feat_type(feat) != FEAT_NN)
-		return -EINVAL;
-	return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val);
-}
 
 /*
  *	Tracking features whose value depend on the choice of CCID
diff --git a/net/dccp/feat.h b/net/dccp/feat.h
index f96721619de..e56a4e5e634 100644
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -111,7 +111,6 @@ extern int  dccp_feat_init(struct sock *sk);
 extern void dccp_feat_initialise_sysctls(void);
 extern int  dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
 				  u8 const *list, u8 len);
-extern int  dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);
 extern int  dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,
 				    u8 mand, u8 opt, u8 feat, u8 *val, u8 len);
 extern int  dccp_feat_clone_list(struct list_head const *, struct list_head *);
diff --git a/net/dccp/input.c b/net/dccp/input.c
index 10c957a88f4..265985370fa 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -259,7 +259,7 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
 				      sysctl_dccp_sync_ratelimit)))
 			return 0;
 
-		DCCP_WARN("DCCP: Step 6 failed for %s packet, "
+		DCCP_WARN("Step 6 failed for %s packet, "
 			  "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
 			  "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
 			  "sending SYNC...\n",  dccp_packet_name(dh->dccph_type),
@@ -441,20 +441,14 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
 		kfree_skb(sk->sk_send_head);
 		sk->sk_send_head = NULL;
 
-		dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
-		dccp_update_gsr(sk, dp->dccps_isr);
 		/*
-		 * SWL and AWL are initially adjusted so that they are not less than
-		 * the initial Sequence Numbers received and sent, respectively:
-		 *	SWL := max(GSR + 1 - floor(W/4), ISR),
-		 *	AWL := max(GSS - W' + 1, ISS).
-		 * These adjustments MUST be applied only at the beginning of the
-		 * connection.
-		 *
-		 * AWL was adjusted in dccp_v4_connect -acme
+		 * Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect
+		 * and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH
+		 * is done as part of activating the feature values below, since
+		 * these settings depend on the local/remote Sequence Window
+		 * features, which were undefined or not confirmed until now.
 		 */
-		dccp_set_seqno(&dp->dccps_swl,
-			       max48(dp->dccps_swl, dp->dccps_isr));
+		dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
 
 		dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
 
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index d4a166f0f39..3f69ea11482 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -392,7 +392,7 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	newsk = dccp_create_openreq_child(sk, req, skb);
 	if (newsk == NULL)
-		goto exit;
+		goto exit_nonewsk;
 
 	sk_setup_caps(newsk, dst);
 
@@ -409,16 +409,20 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	dccp_sync_mss(newsk, dst_mtu(dst));
 
+	if (__inet_inherit_port(sk, newsk) < 0) {
+		sock_put(newsk);
+		goto exit;
+	}
 	__inet_hash_nolisten(newsk, NULL);
-	__inet_inherit_port(sk, newsk);
 
 	return newsk;
 
 exit_overflow:
 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
+exit_nonewsk:
+	dst_release(dst);
 exit:
 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
-	dst_release(dst);
 	return NULL;
 }
 
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 6e3f32575df..dca711df9b6 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -564,7 +564,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 
 	newsk = dccp_create_openreq_child(sk, req, skb);
 	if (newsk == NULL)
-		goto out;
+		goto out_nonewsk;
 
 	/*
 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
@@ -632,18 +632,22 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 
+	if (__inet_inherit_port(sk, newsk) < 0) {
+		sock_put(newsk);
+		goto out;
+	}
 	__inet6_hash(newsk, NULL);
-	__inet_inherit_port(sk, newsk);
 
 	return newsk;
 
 out_overflow:
 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
+out_nonewsk:
+	dst_release(dst);
 out:
 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 	if (opt != NULL && opt != np->opt)
 		sock_kfree_s(sk, opt, opt->tot_len);
-	dst_release(dst);
 	return NULL;
 }
 
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index 128b089d3ae..d7041a0963a 100644
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -121,30 +121,18 @@ struct sock *dccp_create_openreq_child(struct sock *sk,
 		 *
 		 *    Choose S.ISS (initial seqno) or set from Init Cookies
 		 *    Initialize S.GAR := S.ISS
-		 *    Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
-		 */
-		newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
-		dccp_update_gss(newsk, dreq->dreq_iss);
-
-		newdp->dccps_isr = dreq->dreq_isr;
-		dccp_update_gsr(newsk, dreq->dreq_isr);
-
-		/*
-		 * SWL and AWL are initially adjusted so that they are not less than
-		 * the initial Sequence Numbers received and sent, respectively:
-		 *	SWL := max(GSR + 1 - floor(W/4), ISR),
-		 *	AWL := max(GSS - W' + 1, ISS).
-		 * These adjustments MUST be applied only at the beginning of the
-		 * connection.
+		 *    Set S.ISR, S.GSR from packet (or Init Cookies)
+		 *
+		 *    Setting AWL/AWH and SWL/SWH happens as part of the feature
+		 *    activation below, as these windows all depend on the local
+		 *    and remote Sequence Window feature values (7.5.2).
 		 */
-		dccp_set_seqno(&newdp->dccps_swl,
-			       max48(newdp->dccps_swl, newdp->dccps_isr));
-		dccp_set_seqno(&newdp->dccps_awl,
-			       max48(newdp->dccps_awl, newdp->dccps_iss));
+		newdp->dccps_gss = newdp->dccps_iss = dreq->dreq_iss;
+		newdp->dccps_gar = newdp->dccps_iss;
+		newdp->dccps_gsr = newdp->dccps_isr = dreq->dreq_isr;
 
 		/*
-		 * Activate features after initialising the sequence numbers,
-		 * since CCID initialisation may depend on GSS, ISR, ISS etc.
+		 * Activate features: initialise CCIDs, sequence windows etc.
 		 */
 		if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
 			/* It is still raw copy of parent, so invalidate
diff --git a/net/dccp/options.c b/net/dccp/options.c
index bfda087bd90..cd306181300 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -96,18 +96,11 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
 		}
 
 		/*
-		 * CCID-Specific Options (from RFC 4340, sec. 10.3):
-		 *
-		 * Option numbers 128 through 191 are for options sent from the
-		 * HC-Sender to the HC-Receiver; option numbers 192 through 255
-		 * are for options sent from the HC-Receiver to	the HC-Sender.
-		 *
 		 * CCID-specific options are ignored during connection setup, as
 		 * negotiation may still be in progress (see RFC 4340, 10.3).
 		 * The same applies to Ack Vectors, as these depend on the CCID.
-		 *
 		 */
-		if (dreq != NULL && (opt >= 128 ||
+		if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC ||
 		    opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
 			goto ignore_option;
 
@@ -170,6 +163,8 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
 				      dccp_role(sk), ntohl(opt_val),
 				      (unsigned long long)
 				      DCCP_SKB_CB(skb)->dccpd_ack_seq);
+			/* schedule an Ack in case this sender is quiescent */
+			inet_csk_schedule_ack(sk);
 			break;
 		case DCCPO_TIMESTAMP_ECHO:
 			if (len != 4 && len != 6 && len != 8)
@@ -226,23 +221,15 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
 			dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
 				      dccp_role(sk), elapsed_time);
 			break;
-		case 128 ... 191: {
-			const u16 idx = value - options;
-
+		case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC:
 			if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
-						     opt, len, idx,
-						     value) != 0)
+						     pkt_type, opt, value, len))
 				goto out_invalid_option;
-		}
 			break;
-		case 192 ... 255: {
-			const u16 idx = value - options;
-
+		case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC:
 			if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
-						     opt, len, idx,
-						     value) != 0)
+						     pkt_type, opt, value, len))
 				goto out_invalid_option;
-		}
 			break;
 		default:
 			DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
@@ -384,7 +371,7 @@ int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time)
 
 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
 
-int dccp_insert_option_timestamp(struct sk_buff *skb)
+static int dccp_insert_option_timestamp(struct sk_buff *skb)
 {
 	__be32 now = htonl(dccp_timestamp());
 	/* yes this will overflow but that is the point as we want a
@@ -393,8 +380,6 @@ int dccp_insert_option_timestamp(struct sk_buff *skb)
 	return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
 }
 
-EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
-
 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
 					     struct dccp_request_sock *dreq,
 					     struct sk_buff *skb)
diff --git a/net/dccp/output.c b/net/dccp/output.c
index aadbdb58758..a988fe9ffcb 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -304,7 +304,7 @@ void dccp_write_xmit(struct sock *sk, int block)
 				dcb->dccpd_type = DCCP_PKT_DATA;
 
 			err = dccp_transmit_skb(sk, skb);
-			ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
+			ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len);
 			if (err)
 				DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
 					 err);
@@ -474,8 +474,9 @@ int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
 /*
  * Do all connect socket setups that can be done AF independent.
  */
-static inline void dccp_connect_init(struct sock *sk)
+int dccp_connect(struct sock *sk)
 {
+	struct sk_buff *skb;
 	struct dccp_sock *dp = dccp_sk(sk);
 	struct dst_entry *dst = __sk_dst_get(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
@@ -485,22 +486,12 @@ static inline void dccp_connect_init(struct sock *sk)
 
 	dccp_sync_mss(sk, dst_mtu(dst));
 
-	/* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
-	dp->dccps_gar = dp->dccps_iss;
-
-	icsk->icsk_retransmits = 0;
-}
-
-int dccp_connect(struct sock *sk)
-{
-	struct sk_buff *skb;
-	struct inet_connection_sock *icsk = inet_csk(sk);
-
 	/* do not connect if feature negotiation setup fails */
 	if (dccp_feat_finalise_settings(dccp_sk(sk)))
 		return -EPROTO;
 
-	dccp_connect_init(sk);
+	/* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
+	dp->dccps_gar = dp->dccps_iss;
 
 	skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
 	if (unlikely(skb == NULL))
@@ -516,6 +507,7 @@ int dccp_connect(struct sock *sk)
 	DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
 
 	/* Timer for repeating the REQUEST until an answer. */
+	icsk->icsk_retransmits = 0;
 	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
 				  icsk->icsk_rto, DCCP_RTO_MAX);
 	return 0;
diff --git a/net/dccp/probe.c b/net/dccp/probe.c
index 078e48d442f..33d0e6297c2 100644
--- a/net/dccp/probe.c
+++ b/net/dccp/probe.c
@@ -149,6 +149,7 @@ static const struct file_operations dccpprobe_fops = {
 	.owner	 = THIS_MODULE,
 	.open	 = dccpprobe_open,
 	.read    = dccpprobe_read,
+	.llseek  = noop_llseek,
 };
 
 static __init int dccpprobe_init(void)
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 096250d1323..7e5fc04eb6d 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -50,6 +50,30 @@ EXPORT_SYMBOL_GPL(dccp_hashinfo);
 /* the maximum queue length for tx in packets. 0 is no limit */
 int sysctl_dccp_tx_qlen __read_mostly = 5;
 
+#ifdef CONFIG_IP_DCCP_DEBUG
+static const char *dccp_state_name(const int state)
+{
+	static const char *const dccp_state_names[] = {
+	[DCCP_OPEN]		= "OPEN",
+	[DCCP_REQUESTING]	= "REQUESTING",
+	[DCCP_PARTOPEN]		= "PARTOPEN",
+	[DCCP_LISTEN]		= "LISTEN",
+	[DCCP_RESPOND]		= "RESPOND",
+	[DCCP_CLOSING]		= "CLOSING",
+	[DCCP_ACTIVE_CLOSEREQ]	= "CLOSEREQ",
+	[DCCP_PASSIVE_CLOSE]	= "PASSIVE_CLOSE",
+	[DCCP_PASSIVE_CLOSEREQ]	= "PASSIVE_CLOSEREQ",
+	[DCCP_TIME_WAIT]	= "TIME_WAIT",
+	[DCCP_CLOSED]		= "CLOSED",
+	};
+
+	if (state >= DCCP_MAX_STATES)
+		return "INVALID STATE!";
+	else
+		return dccp_state_names[state];
+}
+#endif
+
 void dccp_set_state(struct sock *sk, const int state)
 {
 	const int oldstate = sk->sk_state;
@@ -146,30 +170,6 @@ const char *dccp_packet_name(const int type)
 
 EXPORT_SYMBOL_GPL(dccp_packet_name);
 
-const char *dccp_state_name(const int state)
-{
-	static const char *const dccp_state_names[] = {
-	[DCCP_OPEN]		= "OPEN",
-	[DCCP_REQUESTING]	= "REQUESTING",
-	[DCCP_PARTOPEN]		= "PARTOPEN",
-	[DCCP_LISTEN]		= "LISTEN",
-	[DCCP_RESPOND]		= "RESPOND",
-	[DCCP_CLOSING]		= "CLOSING",
-	[DCCP_ACTIVE_CLOSEREQ]	= "CLOSEREQ",
-	[DCCP_PASSIVE_CLOSE]	= "PASSIVE_CLOSE",
-	[DCCP_PASSIVE_CLOSEREQ]	= "PASSIVE_CLOSEREQ",
-	[DCCP_TIME_WAIT]	= "TIME_WAIT",
-	[DCCP_CLOSED]		= "CLOSED",
-	};
-
-	if (state >= DCCP_MAX_STATES)
-		return "INVALID STATE!";
-	else
-		return dccp_state_names[state];
-}
-
-EXPORT_SYMBOL_GPL(dccp_state_name);
-
 int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
@@ -944,7 +944,7 @@ void dccp_close(struct sock *sk, long timeout)
 
 	if (data_was_unread) {
 		/* Unread data was tossed, send an appropriate Reset Code */
-		DCCP_WARN("DCCP: ABORT -- %u bytes unread\n", data_was_unread);
+		DCCP_WARN("ABORT with %u bytes unread\n", data_was_unread);
 		dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
 		dccp_set_state(sk, DCCP_CLOSED);
 	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {