Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 166 insertions, 278 deletions

diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 9b3ae9922be1..fadecd20d75b 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)
@@ -123,12 +78,9 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
 
 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 {
-        struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-
-        if (hc->tx_pipe < hc->tx_cwnd)
-                return 0;
-
-        return 1; /* XXX CCID should dequeue when ready instead of polling */
+        if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk)))
+                return CCID_PACKET_WILL_DEQUEUE_LATER;
+        return CCID_PACKET_SEND_AT_ONCE;
 }
 
 static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
@@ -156,19 +108,11 @@ 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;
+        const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
 
         bh_lock_sock(sk);
         if (sock_owned_by_user(sk)) {
@@ -178,23 +122,17 @@ 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;
-
-        s = hc->tx_rto / HZ;
-        if (s > 60)
-                hc->tx_rto = 60 * HZ;
-
-        ccid2_start_rto_timer(sk);
+        if (hc->tx_rto > DCCP_RTO_MAX)
+                hc->tx_rto = DCCP_RTO_MAX;
 
         /* 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 +142,18 @@ 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);
+
+        /* if we were blocked before, we may now send cwnd=1 packet */
+        if (sender_was_blocked)
+                tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
+        /* restart backed-off timer */
+        sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
 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 +163,7 @@ 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 */
@@ -296,99 +229,104 @@ 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
 }
 
-/* XXX Lame code duplication!
- * returns -1 if none was found.
- * else returns the next offset to use in the function call.
+/**
+ * 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 int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
-                           unsigned char **vec, unsigned char *veclen)
+static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
 {
-        const struct dccp_hdr *dh = dccp_hdr(skb);
-        unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
-        unsigned char *opt_ptr;
-        const unsigned char *opt_end = (unsigned char *)dh +
-                                        (dh->dccph_doff * 4);
-        unsigned char opt, len;
-        unsigned char *value;
-
-        BUG_ON(offset < 0);
-        options += offset;
-        opt_ptr = options;
-        if (opt_ptr >= opt_end)
-                return -1;
-
-        while (opt_ptr != opt_end) {
-                opt   = *opt_ptr++;
-                len   = 0;
-                value = NULL;
-
-                /* Check if this isn't a single byte option */
-                if (opt > DCCPO_MAX_RESERVED) {
-                        if (opt_ptr == opt_end)
-                                goto out_invalid_option;
-
-                        len = *opt_ptr++;
-                        if (len < 3)
-                                goto out_invalid_option;
+        struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+        long m = mrtt ? : 1;
+
+        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);
                         /*
-                         * Remove the type and len fields, leaving
-                         * just the value size
+                         * This neutralises RTO increase when RTT < SRTT - mdev
+                         * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
+                         * in Linux TCP", USENIX 2002, pp. 49-62).
                          */
-                        len     -= 2;
-                        value   = opt_ptr;
-                        opt_ptr += len;
+                        if (m > 0)
+                                m >>= 3;
+                } else {
+                        m -= (hc->tx_mdev >> 2);
+                }
+                hc->tx_mdev += m;
 
-                        if (opt_ptr > opt_end)
-                                goto out_invalid_option;
+                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;
                 }
 
-                switch (opt) {
-                case DCCPO_ACK_VECTOR_0:
-                case DCCPO_ACK_VECTOR_1:
-                        *vec    = value;
-                        *veclen = len;
-                        return offset + (opt_ptr - options);
+                /*
+                 * 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);
                 }
         }
 
-        return -1;
-
-out_invalid_option:
-        DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
-        return -1;
-}
-
-static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
-{
-        struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(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;
 
-        sk_stop_timer(sk, &hc->tx_rtotimer);
-        ccid2_pr_debug("deleted RTO timer\n");
+        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 +340,27 @@ 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);
@@ -498,19 +370,31 @@ static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
                 ccid2_change_l_ack_ratio(sk, hc->tx_cwnd);
 }
 
+static int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+                                     u8 option, u8 *optval, u8 optlen)
+{
+        struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+
+        switch (option) {
+        case DCCPO_ACK_VECTOR_0:
+        case DCCPO_ACK_VECTOR_1:
+                return dccp_ackvec_parsed_add(&hc->tx_av_chunks, optval, optlen,
+                                              option - DCCPO_ACK_VECTOR_0);
+        }
+        return 0;
+}
+
 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 {
         struct dccp_sock *dp = dccp_sk(sk);
         struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+        const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
+        struct dccp_ackvec_parsed *avp;
         u64 ackno, seqno;
         struct ccid2_seq *seqp;
-        unsigned char *vector;
-        unsigned char veclen;
-        int offset = 0;
         int done = 0;
         unsigned int maxincr = 0;
 
-        ccid2_hc_tx_check_sanity(hc);
         /* check reverse path congestion */
         seqno = DCCP_SKB_CB(skb)->dccpd_seq;
 
@@ -541,17 +425,12 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
         }
 
         /* check forward path congestion */
-        /* still didn't send out new data packets */
-        if (hc->tx_seqh == hc->tx_seqt)
+        if (dccp_packet_without_ack(skb))
                 return;
 
-        switch (DCCP_SKB_CB(skb)->dccpd_type) {
-        case DCCP_PKT_ACK:
-        case DCCP_PKT_DATAACK:
-                break;
-        default:
-                return;
-        }
+        /* still didn't send out new data packets */
+        if (hc->tx_seqh == hc->tx_seqt)
+                goto done;
 
         ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
         if (after48(ackno, hc->tx_high_ack))
@@ -575,16 +454,16 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
 
         /* go through all ack vectors */
-        while ((offset = ccid2_ackvector(sk, skb, offset,
-                                         &vector, &veclen)) != -1) {
+        list_for_each_entry(avp, &hc->tx_av_chunks, node) {
                 /* go through this ack vector */
-                while (veclen--) {
-                        const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
-                        u64 ackno_end_rl = SUB48(ackno, rl);
+                for (; avp->len--; avp->vec++) {
+                        u64 ackno_end_rl = SUB48(ackno,
+                                                 dccp_ackvec_runlen(avp->vec));
 
-                        ccid2_pr_debug("ackvec start:%llu end:%llu\n",
+                        ccid2_pr_debug("ackvec %llu |%u,%u|\n",
                                        (unsigned long long)ackno,
-                                       (unsigned long long)ackno_end_rl);
+                                       dccp_ackvec_state(avp->vec) >> 6,
+                                       dccp_ackvec_runlen(avp->vec));
                         /* if the seqno we are analyzing is larger than the
                          * current ackno, then move towards the tail of our
                          * seqnos.
@@ -603,24 +482,22 @@ 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;
+                                const u8 state = dccp_ackvec_state(avp->vec);
 
                                 /* new packet received or marked */
-                                if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
+                                if (state != DCCPAV_NOT_RECEIVED &&
                                     !seqp->ccid2s_acked) {
-                                        if (state ==
-                                            DCCP_ACKVEC_STATE_ECN_MARKED) {
+                                        if (state == DCCPAV_ECN_MARKED)
                                                 ccid2_congestion_event(sk,
                                                                        seqp);
-                                        } else
+                                        else
                                                 ccid2_new_ack(sk, seqp,
                                                               &maxincr);
 
                                         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;
@@ -632,7 +509,6 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                                 break;
 
                         ackno = SUB48(ackno_end_rl, 1);
-                        vector++;
                 }
                 if (done)
                         break;
@@ -677,7 +553,7 @@ 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 +571,25 @@ 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);
+done:
+        /* check if incoming Acks allow pending packets to be sent */
+        if (sender_was_blocked && !ccid2_cwnd_network_limited(hc))
+                tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
+        dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks);
+}
+
+/*
+ * Convert RFC 3390 larger initial window into an equivalent number of packets.
+ * This is based on the numbers specified in RFC 5681, 3.1.
+ */
+static inline u32 rfc3390_bytes_to_packets(const u32 smss)
+{
+        return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
 }
 
 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -707,12 +601,8 @@ 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 +613,12 @@ 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);
+        INIT_LIST_HEAD(&hc->tx_av_chunks);
         return 0;
 }
 
@@ -740,7 +627,7 @@ 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]);
@@ -765,16 +652,17 @@ static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 }
 
 struct ccid_operations ccid2_ops = {
-        .ccid_id                = DCCPC_CCID2,
-        .ccid_name              = "TCP-like",
-        .ccid_hc_tx_obj_size    = sizeof(struct ccid2_hc_tx_sock),
-        .ccid_hc_tx_init        = ccid2_hc_tx_init,
-        .ccid_hc_tx_exit        = ccid2_hc_tx_exit,
-        .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
-        .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
-        .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
-        .ccid_hc_rx_obj_size    = sizeof(struct ccid2_hc_rx_sock),
-        .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
+        .ccid_id                  = DCCPC_CCID2,
+        .ccid_name                = "TCP-like",
+        .ccid_hc_tx_obj_size      = sizeof(struct ccid2_hc_tx_sock),
+        .ccid_hc_tx_init          = ccid2_hc_tx_init,
+        .ccid_hc_tx_exit          = ccid2_hc_tx_exit,
+        .ccid_hc_tx_send_packet   = ccid2_hc_tx_send_packet,
+        .ccid_hc_tx_packet_sent   = ccid2_hc_tx_packet_sent,
+        .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options,
+        .ccid_hc_tx_packet_recv   = ccid2_hc_tx_packet_recv,
+        .ccid_hc_rx_obj_size      = sizeof(struct ccid2_hc_rx_sock),
+        .ccid_hc_rx_packet_recv   = ccid2_hc_rx_packet_recv,
 };
 
 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG