Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff
[linux-2.6.git] / net / ipv4 / tcp_input.c
index 5bad504..662bd24 100644 (file)
@@ -42,7 +42,7 @@
  *             Andi Kleen      :       Moved open_request checking here
  *                                     and process RSTs for open_requests.
  *             Andi Kleen      :       Better prune_queue, and other fixes.
- *             Andrey Savochkin:       Fix RTT measurements in the presnce of
+ *             Andrey Savochkin:       Fix RTT measurements in the presence of
  *                                     timestamps.
  *             Andrey Savochkin:       Check sequence numbers correctly when
  *                                     removing SACKs due to in sequence incoming
@@ -61,7 +61,6 @@
  *             Panu Kuhlberg:          Experimental audit of TCP (re)transmission
  *                                     engine. Lots of bugs are found.
  *             Pasi Sarolahti:         F-RTO for dealing with spurious RTOs
- *             Angelo Dell'Aera:       TCP Westwood+ support
  */
 
 #include <linux/config.h>
@@ -88,22 +87,9 @@ int sysctl_tcp_rfc1337;
 int sysctl_tcp_max_orphans = NR_FILE;
 int sysctl_tcp_frto;
 int sysctl_tcp_nometrics_save;
-int sysctl_tcp_westwood;
-int sysctl_tcp_vegas_cong_avoid;
 
 int sysctl_tcp_moderate_rcvbuf = 1;
-
-/* Default values of the Vegas variables, in fixed-point representation
- * with V_PARAM_SHIFT bits to the right of the binary point.
- */
-#define V_PARAM_SHIFT 1
-int sysctl_tcp_vegas_alpha = 1<<V_PARAM_SHIFT;
-int sysctl_tcp_vegas_beta  = 3<<V_PARAM_SHIFT;
-int sysctl_tcp_vegas_gamma = 1<<V_PARAM_SHIFT;
-int sysctl_tcp_bic = 1;
-int sysctl_tcp_bic_fast_convergence = 1;
-int sysctl_tcp_bic_low_window = 14;
-int sysctl_tcp_bic_beta = 819;         /* = 819/1024 (BICTCP_BETA_SCALE) */
+int sysctl_tcp_abc = 1;
 
 #define FLAG_DATA              0x01 /* Incoming frame contained data.          */
 #define FLAG_WIN_UPDATE                0x02 /* Incoming ACK was a window update.       */
@@ -129,20 +115,21 @@ int sysctl_tcp_bic_beta = 819;            /* = 819/1024 (BICTCP_BETA_SCALE) */
 /* Adapt the MSS value used to make delayed ack decision to the 
  * real world.
  */ 
-static inline void tcp_measure_rcv_mss(struct tcp_sock *tp,
-                                      struct sk_buff *skb)
+static void tcp_measure_rcv_mss(struct sock *sk,
+                               const struct sk_buff *skb)
 {
-       unsigned int len, lss;
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       const unsigned int lss = icsk->icsk_ack.last_seg_size; 
+       unsigned int len;
 
-       lss = tp->ack.last_seg_size; 
-       tp->ack.last_seg_size = 0; 
+       icsk->icsk_ack.last_seg_size = 0; 
 
        /* skb->len may jitter because of SACKs, even if peer
         * sends good full-sized frames.
         */
        len = skb->len;
-       if (len >= tp->ack.rcv_mss) {
-               tp->ack.rcv_mss = len;
+       if (len >= icsk->icsk_ack.rcv_mss) {
+               icsk->icsk_ack.rcv_mss = len;
        } else {
                /* Otherwise, we make more careful check taking into account,
                 * that SACKs block is variable.
@@ -162,41 +149,44 @@ static inline void tcp_measure_rcv_mss(struct tcp_sock *tp,
                         * tcp header plus fixed timestamp option length.
                         * Resulting "len" is MSS free of SACK jitter.
                         */
-                       len -= tp->tcp_header_len;
-                       tp->ack.last_seg_size = len;
+                       len -= tcp_sk(sk)->tcp_header_len;
+                       icsk->icsk_ack.last_seg_size = len;
                        if (len == lss) {
-                               tp->ack.rcv_mss = len;
+                               icsk->icsk_ack.rcv_mss = len;
                                return;
                        }
                }
-               tp->ack.pending |= TCP_ACK_PUSHED;
+               icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
        }
 }
 
-static void tcp_incr_quickack(struct tcp_sock *tp)
+static void tcp_incr_quickack(struct sock *sk)
 {
-       unsigned quickacks = tp->rcv_wnd/(2*tp->ack.rcv_mss);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       unsigned quickacks = tcp_sk(sk)->rcv_wnd / (2 * icsk->icsk_ack.rcv_mss);
 
        if (quickacks==0)
                quickacks=2;
-       if (quickacks > tp->ack.quick)
-               tp->ack.quick = min(quickacks, TCP_MAX_QUICKACKS);
+       if (quickacks > icsk->icsk_ack.quick)
+               icsk->icsk_ack.quick = min(quickacks, TCP_MAX_QUICKACKS);
 }
 
-void tcp_enter_quickack_mode(struct tcp_sock *tp)
+void tcp_enter_quickack_mode(struct sock *sk)
 {
-       tcp_incr_quickack(tp);
-       tp->ack.pingpong = 0;
-       tp->ack.ato = TCP_ATO_MIN;
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       tcp_incr_quickack(sk);
+       icsk->icsk_ack.pingpong = 0;
+       icsk->icsk_ack.ato = TCP_ATO_MIN;
 }
 
 /* Send ACKs quickly, if "quick" count is not exhausted
  * and the session is not interactive.
  */
 
-static __inline__ int tcp_in_quickack_mode(struct tcp_sock *tp)
+static inline int tcp_in_quickack_mode(const struct sock *sk)
 {
-       return (tp->ack.quick && !tp->ack.pingpong);
+       const struct inet_connection_sock *icsk = inet_csk(sk);
+       return icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong;
 }
 
 /* Buffer size and advertised window tuning.
@@ -234,21 +224,21 @@ static void tcp_fixup_sndbuf(struct sock *sk)
  *   of receiver window. Check #2.
  *
  * The scheme does not work when sender sends good segments opening
- * window and then starts to feed us spagetti. But it should work
+ * window and then starts to feed us spaghetti. But it should work
  * in common situations. Otherwise, we have to rely on queue collapsing.
  */
 
 /* Slow part of check#2. */
-static int __tcp_grow_window(struct sock *sk, struct tcp_sock *tp,
-                            struct sk_buff *skb)
+static int __tcp_grow_window(const struct sock *sk, struct tcp_sock *tp,
+                            const struct sk_buff *skb)
 {
        /* Optimize this! */
        int truesize = tcp_win_from_space(skb->truesize)/2;
-       int window = tcp_full_space(sk)/2;
+       int window = tcp_win_from_space(sysctl_tcp_rmem[2])/2;
 
        while (tp->rcv_ssthresh <= window) {
                if (truesize <= skb->len)
-                       return 2*tp->ack.rcv_mss;
+                       return 2 * inet_csk(sk)->icsk_ack.rcv_mss;
 
                truesize >>= 1;
                window >>= 1;
@@ -256,8 +246,8 @@ static int __tcp_grow_window(struct sock *sk, struct tcp_sock *tp,
        return 0;
 }
 
-static inline void tcp_grow_window(struct sock *sk, struct tcp_sock *tp,
-                                  struct sk_buff *skb)
+static void tcp_grow_window(struct sock *sk, struct tcp_sock *tp,
+                           struct sk_buff *skb)
 {
        /* Check #1 */
        if (tp->rcv_ssthresh < tp->window_clamp &&
@@ -275,7 +265,7 @@ static inline void tcp_grow_window(struct sock *sk, struct tcp_sock *tp,
 
                if (incr) {
                        tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr, tp->window_clamp);
-                       tp->ack.quick |= 1;
+                       inet_csk(sk)->icsk_ack.quick |= 1;
                }
        }
 }
@@ -288,7 +278,7 @@ static void tcp_fixup_rcvbuf(struct sock *sk)
        int rcvmem = tp->advmss + MAX_TCP_HEADER + 16 + sizeof(struct sk_buff);
 
        /* Try to select rcvbuf so that 4 mss-sized segments
-        * will fit to window and correspoding skbs will fit to our rcvbuf.
+        * will fit to window and corresponding skbs will fit to our rcvbuf.
         * (was 3; 4 is minimum to allow fast retransmit to work.)
         */
        while (tcp_win_from_space(rcvmem) < tp->advmss)
@@ -297,7 +287,7 @@ static void tcp_fixup_rcvbuf(struct sock *sk)
                sk->sk_rcvbuf = min(4 * rcvmem, sysctl_tcp_rmem[2]);
 }
 
-/* 4. Try to fixup all. It is made iimediately after connection enters
+/* 4. Try to fixup all. It is made immediately after connection enters
  *    established state.
  */
 static void tcp_init_buffer_space(struct sock *sk)
@@ -333,51 +323,42 @@ static void tcp_init_buffer_space(struct sock *sk)
        tp->snd_cwnd_stamp = tcp_time_stamp;
 }
 
-static void init_bictcp(struct tcp_sock *tp)
-{
-       tp->bictcp.cnt = 0;
-
-       tp->bictcp.last_max_cwnd = 0;
-       tp->bictcp.last_cwnd = 0;
-       tp->bictcp.last_stamp = 0;
-}
-
 /* 5. Recalculate window clamp after socket hit its memory bounds. */
 static void tcp_clamp_window(struct sock *sk, struct tcp_sock *tp)
 {
-       struct sk_buff *skb;
-       unsigned int app_win = tp->rcv_nxt - tp->copied_seq;
-       int ofo_win = 0;
-
-       tp->ack.quick = 0;
+       struct inet_connection_sock *icsk = inet_csk(sk);
 
-       skb_queue_walk(&tp->out_of_order_queue, skb) {
-               ofo_win += skb->len;
-       }
+       icsk->icsk_ack.quick = 0;
 
-       /* If overcommit is due to out of order segments,
-        * do not clamp window. Try to expand rcvbuf instead.
-        */
-       if (ofo_win) {
-               if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
-                   !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
-                   !tcp_memory_pressure &&
-                   atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0])
-                       sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
-                                           sysctl_tcp_rmem[2]);
+       if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
+           !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
+           !tcp_memory_pressure &&
+           atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
+               sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
+                                   sysctl_tcp_rmem[2]);
        }
-       if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) {
-               app_win += ofo_win;
-               if (atomic_read(&sk->sk_rmem_alloc) >= 2 * sk->sk_rcvbuf)
-                       app_win >>= 1;
-               if (app_win > tp->ack.rcv_mss)
-                       app_win -= tp->ack.rcv_mss;
-               app_win = max(app_win, 2U*tp->advmss);
-
-               if (!ofo_win)
-                       tp->window_clamp = min(tp->window_clamp, app_win);
+       if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
                tp->rcv_ssthresh = min(tp->window_clamp, 2U*tp->advmss);
-       }
+}
+
+
+/* Initialize RCV_MSS value.
+ * RCV_MSS is an our guess about MSS used by the peer.
+ * We haven't any direct information about the MSS.
+ * It's better to underestimate the RCV_MSS rather than overestimate.
+ * Overestimations make us ACKing less frequently than needed.
+ * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss().
+ */
+void tcp_initialize_rcv_mss(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache);
+
+       hint = min(hint, tp->rcv_wnd/2);
+       hint = min(hint, TCP_MIN_RCVMSS);
+       hint = max(hint, TCP_MIN_MSS);
+
+       inet_csk(sk)->icsk_ack.rcv_mss = hint;
 }
 
 /* Receiver "autotuning" code.
@@ -406,8 +387,8 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
                 * are stalled on filesystem I/O.
                 *
                 * Also, since we are only going for a minimum in the
-                * non-timestamp case, we do not smoothe things out
-                * else with timestamps disabled convergance takes too
+                * non-timestamp case, we do not smooth things out
+                * else with timestamps disabled convergence takes too
                 * long.
                 */
                if (!win_dep) {
@@ -416,7 +397,7 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
                } else if (m < new_sample)
                        new_sample = m << 3;
        } else {
-               /* No previous mesaure. */
+               /* No previous measure. */
                new_sample = m << 3;
        }
 
@@ -439,11 +420,12 @@ new_measure:
        tp->rcv_rtt_est.time = tcp_time_stamp;
 }
 
-static inline void tcp_rcv_rtt_measure_ts(struct tcp_sock *tp, struct sk_buff *skb)
+static inline void tcp_rcv_rtt_measure_ts(struct sock *sk, const struct sk_buff *skb)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        if (tp->rx_opt.rcv_tsecr &&
            (TCP_SKB_CB(skb)->end_seq -
-            TCP_SKB_CB(skb)->seq >= tp->ack.rcv_mss))
+            TCP_SKB_CB(skb)->seq >= inet_csk(sk)->icsk_ack.rcv_mss))
                tcp_rcv_rtt_update(tp, tcp_time_stamp - tp->rx_opt.rcv_tsecr, 0);
 }
 
@@ -474,7 +456,8 @@ void tcp_rcv_space_adjust(struct sock *sk)
 
                tp->rcvq_space.space = space;
 
-               if (sysctl_tcp_moderate_rcvbuf) {
+               if (sysctl_tcp_moderate_rcvbuf &&
+                   !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
                        int new_clamp = space;
 
                        /* Receive space grows, normalize in order to
@@ -516,41 +499,42 @@ new_measure:
  */
 static void tcp_event_data_recv(struct sock *sk, struct tcp_sock *tp, struct sk_buff *skb)
 {
+       struct inet_connection_sock *icsk = inet_csk(sk);
        u32 now;
 
-       tcp_schedule_ack(tp);
+       inet_csk_schedule_ack(sk);
 
-       tcp_measure_rcv_mss(tp, skb);
+       tcp_measure_rcv_mss(sk, skb);
 
        tcp_rcv_rtt_measure(tp);
        
        now = tcp_time_stamp;
 
-       if (!tp->ack.ato) {
+       if (!icsk->icsk_ack.ato) {
                /* The _first_ data packet received, initialize
                 * delayed ACK engine.
                 */
-               tcp_incr_quickack(tp);
-               tp->ack.ato = TCP_ATO_MIN;
+               tcp_incr_quickack(sk);
+               icsk->icsk_ack.ato = TCP_ATO_MIN;
        } else {
-               int m = now - tp->ack.lrcvtime;
+               int m = now - icsk->icsk_ack.lrcvtime;
 
                if (m <= TCP_ATO_MIN/2) {
                        /* The fastest case is the first. */
-                       tp->ack.ato = (tp->ack.ato>>1) + TCP_ATO_MIN/2;
-               } else if (m < tp->ack.ato) {
-                       tp->ack.ato = (tp->ack.ato>>1) + m;
-                       if (tp->ack.ato > tp->rto)
-                               tp->ack.ato = tp->rto;
-               } else if (m > tp->rto) {
-                       /* Too long gap. Apparently sender falled to
+                       icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + TCP_ATO_MIN / 2;
+               } else if (m < icsk->icsk_ack.ato) {
+                       icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + m;
+                       if (icsk->icsk_ack.ato > icsk->icsk_rto)
+                               icsk->icsk_ack.ato = icsk->icsk_rto;
+               } else if (m > icsk->icsk_rto) {
+                       /* Too long gap. Apparently sender failed to
                         * restart window, so that we send ACKs quickly.
                         */
-                       tcp_incr_quickack(tp);
+                       tcp_incr_quickack(sk);
                        sk_stream_mem_reclaim(sk);
                }
        }
-       tp->ack.lrcvtime = now;
+       icsk->icsk_ack.lrcvtime = now;
 
        TCP_ECN_check_ce(tp, skb);
 
@@ -558,45 +542,6 @@ static void tcp_event_data_recv(struct sock *sk, struct tcp_sock *tp, struct sk_
                tcp_grow_window(sk, tp, skb);
 }
 
-/* When starting a new connection, pin down the current choice of 
- * congestion algorithm.
- */
-void tcp_ca_init(struct tcp_sock *tp)
-{
-       if (sysctl_tcp_westwood) 
-               tp->adv_cong = TCP_WESTWOOD;
-       else if (sysctl_tcp_bic)
-               tp->adv_cong = TCP_BIC;
-       else if (sysctl_tcp_vegas_cong_avoid) {
-               tp->adv_cong = TCP_VEGAS;
-               tp->vegas.baseRTT = 0x7fffffff;
-               tcp_vegas_enable(tp);
-       } 
-}
-
-/* Do RTT sampling needed for Vegas.
- * Basically we:
- *   o min-filter RTT samples from within an RTT to get the current
- *     propagation delay + queuing delay (we are min-filtering to try to
- *     avoid the effects of delayed ACKs)
- *   o min-filter RTT samples from a much longer window (forever for now)
- *     to find the propagation delay (baseRTT)
- */
-static inline void vegas_rtt_calc(struct tcp_sock *tp, __u32 rtt)
-{
-       __u32 vrtt = rtt + 1; /* Never allow zero rtt or baseRTT */
-
-       /* Filter to find propagation delay: */
-       if (vrtt < tp->vegas.baseRTT) 
-               tp->vegas.baseRTT = vrtt;
-
-       /* Find the min RTT during the last RTT to find
-        * the current prop. delay + queuing delay:
-        */
-       tp->vegas.minRTT = min(tp->vegas.minRTT, vrtt);
-       tp->vegas.cntRTT++;
-}
-
 /* Called to compute a smoothed rtt estimate. The data fed to this
  * routine either comes from timestamps, or from segments that were
  * known _not_ to have been retransmitted [see Karn/Partridge
@@ -606,13 +551,11 @@ static inline void vegas_rtt_calc(struct tcp_sock *tp, __u32 rtt)
  * To save cycles in the RFC 1323 implementation it was better to break
  * it up into three procedures. -- erics
  */
-static void tcp_rtt_estimator(struct tcp_sock *tp, __u32 mrtt)
+static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        long m = mrtt; /* RTT */
 
-       if (tcp_vegas_enabled(tp))
-               vegas_rtt_calc(tp, mrtt);
-
        /*      The following amusing code comes from Jacobson's
         *      article in SIGCOMM '88.  Note that rtt and mdev
         *      are scaled versions of rtt and mean deviation.
@@ -624,7 +567,7 @@ static void tcp_rtt_estimator(struct tcp_sock *tp, __u32 mrtt)
         *
         * Funny. This algorithm seems to be very broken.
         * These formulae increase RTO, when it should be decreased, increase
-        * too slowly, when it should be incresed fastly, decrease too fastly
+        * too slowly, when it should be increased quickly, decrease too quickly
         * etc. I guess in BSD RTO takes ONE value, so that it is absolutely
         * does not matter how to _calculate_ it. Seems, it was trap
         * that VJ failed to avoid. 8)
@@ -669,15 +612,14 @@ static void tcp_rtt_estimator(struct tcp_sock *tp, __u32 mrtt)
                tp->mdev_max = tp->rttvar = max(tp->mdev, TCP_RTO_MIN);
                tp->rtt_seq = tp->snd_nxt;
        }
-
-       tcp_westwood_update_rtt(tp, tp->srtt >> 3);
 }
 
 /* Calculate rto without backoff.  This is the second half of Van Jacobson's
  * routine referred to above.
  */
-static inline void tcp_set_rto(struct tcp_sock *tp)
+static inline void tcp_set_rto(struct sock *sk)
 {
+       const struct tcp_sock *tp = tcp_sk(sk);
        /* Old crap is replaced with new one. 8)
         *
         * More seriously:
@@ -686,24 +628,24 @@ static inline void tcp_set_rto(struct tcp_sock *tp)
         *    at least by solaris and freebsd. "Erratic ACKs" has _nothing_
         *    to do with delayed acks, because at cwnd>2 true delack timeout
         *    is invisible. Actually, Linux-2.4 also generates erratic
-        *    ACKs in some curcumstances.
+        *    ACKs in some circumstances.
         */
-       tp->rto = (tp->srtt >> 3) + tp->rttvar;
+       inet_csk(sk)->icsk_rto = (tp->srtt >> 3) + tp->rttvar;
 
        /* 2. Fixups made earlier cannot be right.
         *    If we do not estimate RTO correctly without them,
         *    all the algo is pure shit and should be replaced
-        *    with correct one. It is exaclty, which we pretend to do.
+        *    with correct one. It is exactly, which we pretend to do.
         */
 }
 
 /* NOTE: clamping at TCP_RTO_MIN is not required, current algo
  * guarantees that rto is higher.
  */
-static inline void tcp_bound_rto(struct tcp_sock *tp)
+static inline void tcp_bound_rto(struct sock *sk)
 {
-       if (tp->rto > TCP_RTO_MAX)
-               tp->rto = TCP_RTO_MAX;
+       if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
+               inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
 }
 
 /* Save metrics learned by this TCP session.
@@ -721,9 +663,10 @@ void tcp_update_metrics(struct sock *sk)
        dst_confirm(dst);
 
        if (dst && (dst->flags&DST_HOST)) {
+               const struct inet_connection_sock *icsk = inet_csk(sk);
                int m;
 
-               if (tp->backoff || !tp->srtt) {
+               if (icsk->icsk_backoff || !tp->srtt) {
                        /* This session failed to estimate rtt. Why?
                         * Probably, no packets returned in time.
                         * Reset our results.
@@ -772,7 +715,7 @@ void tcp_update_metrics(struct sock *sk)
                            tp->snd_cwnd > dst_metric(dst, RTAX_CWND))
                                dst->metrics[RTAX_CWND-1] = tp->snd_cwnd;
                } else if (tp->snd_cwnd > tp->snd_ssthresh &&
-                          tp->ca_state == TCP_CA_Open) {
+                          icsk->icsk_ca_state == TCP_CA_Open) {
                        /* Cong. avoidance phase, cwnd is reliable. */
                        if (!dst_metric_locked(dst, RTAX_SSTHRESH))
                                dst->metrics[RTAX_SSTHRESH-1] =
@@ -805,14 +748,35 @@ __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst)
        __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0);
 
        if (!cwnd) {
-               if (tp->mss_cache_std > 1460)
+               if (tp->mss_cache > 1460)
                        cwnd = 2;
                else
-                       cwnd = (tp->mss_cache_std > 1095) ? 3 : 4;
+                       cwnd = (tp->mss_cache > 1095) ? 3 : 4;
        }
        return min_t(__u32, cwnd, tp->snd_cwnd_clamp);
 }
 
+/* Set slow start threshold and cwnd not falling to slow start */
+void tcp_enter_cwr(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       tp->prior_ssthresh = 0;
+       tp->bytes_acked = 0;
+       if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) {
+               tp->undo_marker = 0;
+               tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk);
+               tp->snd_cwnd = min(tp->snd_cwnd,
+                                  tcp_packets_in_flight(tp) + 1U);
+               tp->snd_cwnd_cnt = 0;
+               tp->high_seq = tp->snd_nxt;
+               tp->snd_cwnd_stamp = tcp_time_stamp;
+               TCP_ECN_queue_cwr(tp);
+
+               tcp_set_ca_state(sk, TCP_CA_CWR);
+       }
+}
+
 /* Initialize metrics on socket. */
 
 static void tcp_init_metrics(struct sock *sk)
@@ -850,7 +814,7 @@ static void tcp_init_metrics(struct sock *sk)
         * to make it more realistic.
         *
         * A bit of theory. RTT is time passed after "normal" sized packet
-        * is sent until it is ACKed. In normal curcumstances sending small
+        * is sent until it is ACKed. In normal circumstances sending small
         * packets force peer to delay ACKs and calculation is correct too.
         * The algorithm is adaptive and, provided we follow specs, it
         * NEVER underestimate RTT. BUT! If peer tries to make some clever
@@ -866,9 +830,9 @@ static void tcp_init_metrics(struct sock *sk)
                tp->mdev = dst_metric(dst, RTAX_RTTVAR);
                tp->mdev_max = tp->rttvar = max(tp->mdev, TCP_RTO_MIN);
        }
-       tcp_set_rto(tp);
-       tcp_bound_rto(tp);
-       if (tp->rto < TCP_TIMEOUT_INIT && !tp->rx_opt.saw_tstamp)
+       tcp_set_rto(sk);
+       tcp_bound_rto(sk);
+       if (inet_csk(sk)->icsk_rto < TCP_TIMEOUT_INIT && !tp->rx_opt.saw_tstamp)
                goto reset;
        tp->snd_cwnd = tcp_init_cwnd(tp, dst);
        tp->snd_cwnd_stamp = tcp_time_stamp;
@@ -882,12 +846,14 @@ reset:
        if (!tp->rx_opt.saw_tstamp && tp->srtt) {
                tp->srtt = 0;
                tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_INIT;
-               tp->rto = TCP_TIMEOUT_INIT;
+               inet_csk(sk)->icsk_rto = TCP_TIMEOUT_INIT;
        }
 }
 
-static void tcp_update_reordering(struct tcp_sock *tp, int metric, int ts)
+static void tcp_update_reordering(struct sock *sk, const int metric,
+                                 const int ts)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        if (metric > tp->reordering) {
                tp->reordering = min(TCP_MAX_REORDERING, metric);
 
@@ -902,7 +868,7 @@ static void tcp_update_reordering(struct tcp_sock *tp, int metric, int ts)
                        NET_INC_STATS_BH(LINUX_MIB_TCPSACKREORDER);
 #if FASTRETRANS_DEBUG > 1
                printk(KERN_DEBUG "Disorder%d %d %u f%u s%u rr%d\n",
-                      tp->rx_opt.sack_ok, tp->ca_state,
+                      tp->rx_opt.sack_ok, inet_csk(sk)->icsk_ca_state,
                       tp->reordering,
                       tp->fackets_out,
                       tp->sacked_out,
@@ -964,6 +930,7 @@ static void tcp_update_reordering(struct tcp_sock *tp, int metric, int ts)
 static int
 tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_una)
 {
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        unsigned char *ptr = ack_skb->h.raw + TCP_SKB_CB(ack_skb)->sacked;
        struct tcp_sack_block *sp = (struct tcp_sack_block *)(ptr+2);
@@ -972,26 +939,32 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
        int prior_fackets;
        u32 lost_retrans = 0;
        int flag = 0;
+       int dup_sack = 0;
        int i;
 
-       /* So, SACKs for already sent large segments will be lost.
-        * Not good, but alternative is to resegment the queue. */
-       if (sk->sk_route_caps & NETIF_F_TSO) {
-               sk->sk_route_caps &= ~NETIF_F_TSO;
-               sock_set_flag(sk, SOCK_NO_LARGESEND);
-               tp->mss_cache = tp->mss_cache_std;
-       }
-
        if (!tp->sacked_out)
                tp->fackets_out = 0;
        prior_fackets = tp->fackets_out;
 
-       for (i=0; i<num_sacks; i++, sp++) {
-               struct sk_buff *skb;
-               __u32 start_seq = ntohl(sp->start_seq);
-               __u32 end_seq = ntohl(sp->end_seq);
-               int fack_count = 0;
-               int dup_sack = 0;
+       /* SACK fastpath:
+        * if the only SACK change is the increase of the end_seq of
+        * the first block then only apply that SACK block
+        * and use retrans queue hinting otherwise slowpath */
+       flag = 1;
+       for (i = 0; i< num_sacks; i++) {
+               __u32 start_seq = ntohl(sp[i].start_seq);
+               __u32 end_seq =  ntohl(sp[i].end_seq);
+
+               if (i == 0){
+                       if (tp->recv_sack_cache[i].start_seq != start_seq)
+                               flag = 0;
+               } else {
+                       if ((tp->recv_sack_cache[i].start_seq != start_seq) ||
+                           (tp->recv_sack_cache[i].end_seq != end_seq))
+                               flag = 0;
+               }
+               tp->recv_sack_cache[i].start_seq = start_seq;
+               tp->recv_sack_cache[i].end_seq = end_seq;
 
                /* Check for D-SACK. */
                if (i == 0) {
@@ -1023,26 +996,91 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                        if (before(ack, prior_snd_una - tp->max_window))
                                return 0;
                }
+       }
+
+       if (flag)
+               num_sacks = 1;
+       else {
+               int j;
+               tp->fastpath_skb_hint = NULL;
+
+               /* order SACK blocks to allow in order walk of the retrans queue */
+               for (i = num_sacks-1; i > 0; i--) {
+                       for (j = 0; j < i; j++){
+                               if (after(ntohl(sp[j].start_seq),
+                                         ntohl(sp[j+1].start_seq))){
+                                       sp[j].start_seq = htonl(tp->recv_sack_cache[j+1].start_seq);
+                                       sp[j].end_seq = htonl(tp->recv_sack_cache[j+1].end_seq);
+                                       sp[j+1].start_seq = htonl(tp->recv_sack_cache[j].start_seq);
+                                       sp[j+1].end_seq = htonl(tp->recv_sack_cache[j].end_seq);
+                               }
+
+                       }
+               }
+       }
+
+       /* clear flag as used for different purpose in following code */
+       flag = 0;
+
+       for (i=0; i<num_sacks; i++, sp++) {
+               struct sk_buff *skb;
+               __u32 start_seq = ntohl(sp->start_seq);
+               __u32 end_seq = ntohl(sp->end_seq);
+               int fack_count;
+
+               /* Use SACK fastpath hint if valid */
+               if (tp->fastpath_skb_hint) {
+                       skb = tp->fastpath_skb_hint;
+                       fack_count = tp->fastpath_cnt_hint;
+               } else {
+                       skb = sk->sk_write_queue.next;
+                       fack_count = 0;
+               }
 
                /* Event "B" in the comment above. */
                if (after(end_seq, tp->high_seq))
                        flag |= FLAG_DATA_LOST;
 
-               sk_stream_for_retrans_queue(skb, sk) {
-                       u8 sacked = TCP_SKB_CB(skb)->sacked;
-                       int in_sack;
+               sk_stream_for_retrans_queue_from(skb, sk) {
+                       int in_sack, pcount;
+                       u8 sacked;
+
+                       tp->fastpath_skb_hint = skb;
+                       tp->fastpath_cnt_hint = fack_count;
 
                        /* The retransmission queue is always in order, so
                         * we can short-circuit the walk early.
                         */
-                       if(!before(TCP_SKB_CB(skb)->seq, end_seq))
+                       if (!before(TCP_SKB_CB(skb)->seq, end_seq))
                                break;
 
-                       fack_count += tcp_skb_pcount(skb);
-
                        in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) &&
                                !before(end_seq, TCP_SKB_CB(skb)->end_seq);
 
+                       pcount = tcp_skb_pcount(skb);
+
+                       if (pcount > 1 && !in_sack &&
+                           after(TCP_SKB_CB(skb)->end_seq, start_seq)) {
+                               unsigned int pkt_len;
+
+                               in_sack = !after(start_seq,
+                                                TCP_SKB_CB(skb)->seq);
+
+                               if (!in_sack)
+                                       pkt_len = (start_seq -
+                                                  TCP_SKB_CB(skb)->seq);
+                               else
+                                       pkt_len = (end_seq -
+                                                  TCP_SKB_CB(skb)->seq);
+                               if (tcp_fragment(sk, skb, pkt_len, skb_shinfo(skb)->tso_size))
+                                       break;
+                               pcount = tcp_skb_pcount(skb);
+                       }
+
+                       fack_count += pcount;
+
+                       sacked = TCP_SKB_CB(skb)->sacked;
+
                        /* Account D-SACK for retransmitted packet. */
                        if ((dup_sack && in_sack) &&
                            (sacked & TCPCB_RETRANS) &&
@@ -1084,6 +1122,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                                                TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
                                                tp->lost_out -= tcp_skb_pcount(skb);
                                                tp->retrans_out -= tcp_skb_pcount(skb);
+
+                                               /* clear lost hint */
+                                               tp->retransmit_skb_hint = NULL;
                                        }
                                } else {
                                        /* New sack for not retransmitted frame,
@@ -1096,6 +1137,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                                        if (sacked & TCPCB_LOST) {
                                                TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
                                                tp->lost_out -= tcp_skb_pcount(skb);
+
+                                               /* clear lost hint */
+                                               tp->retransmit_skb_hint = NULL;
                                        }
                                }
 
@@ -1119,6 +1163,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                            (TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_RETRANS)) {
                                TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
                                tp->retrans_out -= tcp_skb_pcount(skb);
+                               tp->retransmit_skb_hint = NULL;
                        }
                }
        }
@@ -1129,7 +1174,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
         * we have to account for reordering! Ugly,
         * but should help.
         */
-       if (lost_retrans && tp->ca_state == TCP_CA_Recovery) {
+       if (lost_retrans && icsk->icsk_ca_state == TCP_CA_Recovery) {
                struct sk_buff *skb;
 
                sk_stream_for_retrans_queue(skb, sk) {
@@ -1142,10 +1187,13 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                            (IsFack(tp) ||
                             !before(lost_retrans,
                                     TCP_SKB_CB(skb)->ack_seq + tp->reordering *
-                                    tp->mss_cache_std))) {
+                                    tp->mss_cache))) {
                                TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
                                tp->retrans_out -= tcp_skb_pcount(skb);
 
+                               /* clear lost hint */
+                               tp->retransmit_skb_hint = NULL;
+
                                if (!(TCP_SKB_CB(skb)->sacked&(TCPCB_LOST|TCPCB_SACKED_ACKED))) {
                                        tp->lost_out += tcp_skb_pcount(skb);
                                        TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
@@ -1158,8 +1206,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 
        tp->left_out = tp->sacked_out + tp->lost_out;
 
-       if ((reord < tp->fackets_out) && tp->ca_state != TCP_CA_Loss)
-               tcp_update_reordering(tp, ((tp->fackets_out + 1) - reord), 0);
+       if ((reord < tp->fackets_out) && icsk->icsk_ca_state != TCP_CA_Loss)
+               tcp_update_reordering(sk, ((tp->fackets_out + 1) - reord), 0);
 
 #if FASTRETRANS_DEBUG > 0
        BUG_TRAP((int)tp->sacked_out >= 0);
@@ -1176,17 +1224,18 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
  */
 void tcp_enter_frto(struct sock *sk)
 {
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
 
        tp->frto_counter = 1;
 
-       if (tp->ca_state <= TCP_CA_Disorder ||
+       if (icsk->icsk_ca_state <= TCP_CA_Disorder ||
             tp->snd_una == tp->high_seq ||
-            (tp->ca_state == TCP_CA_Loss && !tp->retransmits)) {
-               tp->prior_ssthresh = tcp_current_ssthresh(tp);
-               if (!tcp_westwood_ssthresh(tp))
-                       tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+            (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) {
+               tp->prior_ssthresh = tcp_current_ssthresh(sk);
+               tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);
+               tcp_ca_event(sk, CA_EVENT_FRTO);
        }
 
        /* Have to clear retransmission markers here to keep the bookkeeping
@@ -1203,7 +1252,7 @@ void tcp_enter_frto(struct sock *sk)
        }
        tcp_sync_left_out(tp);
 
-       tcp_set_ca_state(tp, TCP_CA_Open);
+       tcp_set_ca_state(sk, TCP_CA_Open);
        tp->frto_highmark = tp->snd_nxt;
 }
 
@@ -1249,11 +1298,11 @@ static void tcp_enter_frto_loss(struct sock *sk)
 
        tp->reordering = min_t(unsigned int, tp->reordering,
                                             sysctl_tcp_reordering);
-       tcp_set_ca_state(tp, TCP_CA_Loss);
+       tcp_set_ca_state(sk, TCP_CA_Loss);
        tp->high_seq = tp->frto_highmark;
        TCP_ECN_queue_cwr(tp);
 
-       init_bictcp(tp);
+       clear_all_retrans_hints(tp);
 }
 
 void tcp_clear_retrans(struct tcp_sock *tp)
@@ -1275,20 +1324,23 @@ void tcp_clear_retrans(struct tcp_sock *tp)
  */
 void tcp_enter_loss(struct sock *sk, int how)
 {
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
        int cnt = 0;
 
        /* Reduce ssthresh if it has not yet been made inside this window. */
-       if (tp->ca_state <= TCP_CA_Disorder || tp->snd_una == tp->high_seq ||
-           (tp->ca_state == TCP_CA_Loss && !tp->retransmits)) {
-               tp->prior_ssthresh = tcp_current_ssthresh(tp);
-               tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+       if (icsk->icsk_ca_state <= TCP_CA_Disorder || tp->snd_una == tp->high_seq ||
+           (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) {
+               tp->prior_ssthresh = tcp_current_ssthresh(sk);
+               tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);
+               tcp_ca_event(sk, CA_EVENT_LOSS);
        }
        tp->snd_cwnd       = 1;
        tp->snd_cwnd_cnt   = 0;
        tp->snd_cwnd_stamp = tcp_time_stamp;
 
+       tp->bytes_acked = 0;
        tcp_clear_retrans(tp);
 
        /* Push undo marker, if it was plain RTO and nothing
@@ -1314,12 +1366,14 @@ void tcp_enter_loss(struct sock *sk, int how)
 
        tp->reordering = min_t(unsigned int, tp->reordering,
                                             sysctl_tcp_reordering);
-       tcp_set_ca_state(tp, TCP_CA_Loss);
+       tcp_set_ca_state(sk, TCP_CA_Loss);
        tp->high_seq = tp->snd_nxt;
        TCP_ECN_queue_cwr(tp);
+
+       clear_all_retrans_hints(tp);
 }
 
-static int tcp_check_sack_reneging(struct sock *sk, struct tcp_sock *tp)
+static int tcp_check_sack_reneging(struct sock *sk)
 {
        struct sk_buff *skb;
 
@@ -1331,12 +1385,14 @@ static int tcp_check_sack_reneging(struct sock *sk, struct tcp_sock *tp)
         */
        if ((skb = skb_peek(&sk->sk_write_queue)) != NULL &&
            (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
+               struct inet_connection_sock *icsk = inet_csk(sk);
                NET_INC_STATS_BH(LINUX_MIB_TCPSACKRENEGING);
 
                tcp_enter_loss(sk, 1);
-               tp->retransmits++;
+               icsk->icsk_retransmits++;
                tcp_retransmit_skb(sk, skb_peek(&sk->sk_write_queue));
-               tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto);
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+                                         icsk->icsk_rto, TCP_RTO_MAX);
                return 1;
        }
        return 0;
@@ -1347,15 +1403,15 @@ static inline int tcp_fackets_out(struct tcp_sock *tp)
        return IsReno(tp) ? tp->sacked_out+1 : tp->fackets_out;
 }
 
-static inline int tcp_skb_timedout(struct tcp_sock *tp, struct sk_buff *skb)
+static inline int tcp_skb_timedout(struct sock *sk, struct sk_buff *skb)
 {
-       return (tcp_time_stamp - TCP_SKB_CB(skb)->when > tp->rto);
+       return (tcp_time_stamp - TCP_SKB_CB(skb)->when > inet_csk(sk)->icsk_rto);
 }
 
 static inline int tcp_head_timedout(struct sock *sk, struct tcp_sock *tp)
 {
        return tp->packets_out &&
-              tcp_skb_timedout(tp, skb_peek(&sk->sk_write_queue));
+              tcp_skb_timedout(sk, skb_peek(&sk->sk_write_queue));
 }
 
 /* Linux NewReno/SACK/FACK/ECN state machine.
@@ -1489,8 +1545,9 @@ static int tcp_time_to_recover(struct sock *sk, struct tcp_sock *tp)
  * in assumption of absent reordering, interpret this as reordering.
  * The only another reason could be bug in receiver TCP.
  */
-static void tcp_check_reno_reordering(struct tcp_sock *tp, int addend)
+static void tcp_check_reno_reordering(struct sock *sk, const int addend)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        u32 holes;
 
        holes = max(tp->lost_out, 1U);
@@ -1498,16 +1555,17 @@ static void tcp_check_reno_reordering(struct tcp_sock *tp, int addend)
 
        if ((tp->sacked_out + holes) > tp->packets_out) {
                tp->sacked_out = tp->packets_out - holes;
-               tcp_update_reordering(tp, tp->packets_out+addend, 0);
+               tcp_update_reordering(sk, tp->packets_out + addend, 0);
        }
 }
 
 /* Emulate SACKs for SACKless connection: account for a new dupack. */
 
-static void tcp_add_reno_sack(struct tcp_sock *tp)
+static void tcp_add_reno_sack(struct sock *sk)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        tp->sacked_out++;
-       tcp_check_reno_reordering(tp, 0);
+       tcp_check_reno_reordering(sk, 0);
        tcp_sync_left_out(tp);
 }
 
@@ -1522,7 +1580,7 @@ static void tcp_remove_reno_sacks(struct sock *sk, struct tcp_sock *tp, int acke
                else
                        tp->sacked_out -= acked-1;
        }
-       tcp_check_reno_reordering(tp, acked);
+       tcp_check_reno_reordering(sk, acked);
        tcp_sync_left_out(tp);
 }
 
@@ -1537,17 +1595,37 @@ static void tcp_mark_head_lost(struct sock *sk, struct tcp_sock *tp,
                               int packets, u32 high_seq)
 {
        struct sk_buff *skb;
-       int cnt = packets;
+       int cnt;
 
-       BUG_TRAP(cnt <= tp->packets_out);
+       BUG_TRAP(packets <= tp->packets_out);
+       if (tp->lost_skb_hint) {
+               skb = tp->lost_skb_hint;
+               cnt = tp->lost_cnt_hint;
+       } else {
+               skb = sk->sk_write_queue.next;
+               cnt = 0;
+       }
 
-       sk_stream_for_retrans_queue(skb, sk) {
-               cnt -= tcp_skb_pcount(skb);
-               if (cnt < 0 || after(TCP_SKB_CB(skb)->end_seq, high_seq))
+       sk_stream_for_retrans_queue_from(skb, sk) {
+               /* TODO: do this better */
+               /* this is not the most efficient way to do this... */
+               tp->lost_skb_hint = skb;
+               tp->lost_cnt_hint = cnt;
+               cnt += tcp_skb_pcount(skb);
+               if (cnt > packets || after(TCP_SKB_CB(skb)->end_seq, high_seq))
                        break;
                if (!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
                        TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
                        tp->lost_out += tcp_skb_pcount(skb);
+
+                       /* clear xmit_retransmit_queue hints
+                        *  if this is beyond hint */
+                       if(tp->retransmit_skb_hint != NULL &&
+                          before(TCP_SKB_CB(skb)->seq,
+                                 TCP_SKB_CB(tp->retransmit_skb_hint)->seq)) {
+
+                               tp->retransmit_skb_hint = NULL;
+                       }
                }
        }
        tcp_sync_left_out(tp);
@@ -1571,16 +1649,31 @@ static void tcp_update_scoreboard(struct sock *sk, struct tcp_sock *tp)
         * Hence, we can detect timed out packets during fast
         * retransmit without falling to slow start.
         */
-       if (tcp_head_timedout(sk, tp)) {
+       if (!IsReno(tp) && tcp_head_timedout(sk, tp)) {
                struct sk_buff *skb;
 
-               sk_stream_for_retrans_queue(skb, sk) {
-                       if (tcp_skb_timedout(tp, skb) &&
-                           !(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
+               skb = tp->scoreboard_skb_hint ? tp->scoreboard_skb_hint
+                       : sk->sk_write_queue.next;
+
+               sk_stream_for_retrans_queue_from(skb, sk) {
+                       if (!tcp_skb_timedout(sk, skb))
+                               break;
+
+                       if (!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
                                TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
                                tp->lost_out += tcp_skb_pcount(skb);
+
+                               /* clear xmit_retrans hint */
+                               if (tp->retransmit_skb_hint &&
+                                   before(TCP_SKB_CB(skb)->seq,
+                                          TCP_SKB_CB(tp->retransmit_skb_hint)->seq))
+
+                                       tp->retransmit_skb_hint = NULL;
                        }
                }
+
+               tp->scoreboard_skb_hint = skb;
+
                tcp_sync_left_out(tp);
        }
 }
@@ -1596,28 +1689,16 @@ static inline void tcp_moderate_cwnd(struct tcp_sock *tp)
 }
 
 /* Decrease cwnd each second ack. */
-
-static void tcp_cwnd_down(struct tcp_sock *tp)
+static void tcp_cwnd_down(struct sock *sk)
 {
+       const struct inet_connection_sock *icsk = inet_csk(sk);
+       struct tcp_sock *tp = tcp_sk(sk);
        int decr = tp->snd_cwnd_cnt + 1;
-       __u32 limit;
-
-       /*
-        * TCP Westwood
-        * Here limit is evaluated as BWestimation*RTTmin (for obtaining it
-        * in packets we use mss_cache). If sysctl_tcp_westwood is off
-        * tcp_westwood_bw_rttmin() returns 0. In such case snd_ssthresh is
-        * still used as usual. It prevents other strange cases in which
-        * BWE*RTTmin could assume value 0. It should not happen but...
-        */
-
-       if (!(limit = tcp_westwood_bw_rttmin(tp)))
-               limit = tp->snd_ssthresh/2;
 
        tp->snd_cwnd_cnt = decr&1;
        decr >>= 1;
 
-       if (decr && tp->snd_cwnd > limit)
+       if (decr && tp->snd_cwnd > icsk->icsk_ca_ops->min_cwnd(sk))
                tp->snd_cwnd -= decr;
 
        tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)+1);
@@ -1651,11 +1732,15 @@ static void DBGUNDO(struct sock *sk, struct tcp_sock *tp, const char *msg)
 #define DBGUNDO(x...) do { } while (0)
 #endif
 
-static void tcp_undo_cwr(struct tcp_sock *tp, int undo)
+static void tcp_undo_cwr(struct sock *sk, const int undo)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
+
        if (tp->prior_ssthresh) {
-               if (tcp_is_bic(tp))
-                       tp->snd_cwnd = max(tp->snd_cwnd, tp->bictcp.last_max_cwnd);
+               const struct inet_connection_sock *icsk = inet_csk(sk);
+
+               if (icsk->icsk_ca_ops->undo_cwnd)
+                       tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk);
                else
                        tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh<<1);
 
@@ -1668,6 +1753,10 @@ static void tcp_undo_cwr(struct tcp_sock *tp, int undo)
        }
        tcp_moderate_cwnd(tp);
        tp->snd_cwnd_stamp = tcp_time_stamp;
+
+       /* There is something screwy going on with the retrans hints after
+          an undo */
+       clear_all_retrans_hints(tp);
 }
 
 static inline int tcp_may_undo(struct tcp_sock *tp)
@@ -1683,9 +1772,9 @@ static int tcp_try_undo_recovery(struct sock *sk, struct tcp_sock *tp)
                /* Happy end! We did not retransmit anything
                 * or our original transmission succeeded.
                 */
-               DBGUNDO(sk, tp, tp->ca_state == TCP_CA_Loss ? "loss" : "retrans");
-               tcp_undo_cwr(tp, 1);
-               if (tp->ca_state == TCP_CA_Loss)
+               DBGUNDO(sk, tp, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans");
+               tcp_undo_cwr(sk, 1);
+               if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss)
                        NET_INC_STATS_BH(LINUX_MIB_TCPLOSSUNDO);
                else
                        NET_INC_STATS_BH(LINUX_MIB_TCPFULLUNDO);
@@ -1698,7 +1787,7 @@ static int tcp_try_undo_recovery(struct sock *sk, struct tcp_sock *tp)
                tcp_moderate_cwnd(tp);
                return 1;
        }
-       tcp_set_ca_state(tp, TCP_CA_Open);
+       tcp_set_ca_state(sk, TCP_CA_Open);
        return 0;
 }
 
@@ -1707,7 +1796,7 @@ static void tcp_try_undo_dsack(struct sock *sk, struct tcp_sock *tp)
 {
        if (tp->undo_marker && !tp->undo_retrans) {
                DBGUNDO(sk, tp, "D-SACK");
-               tcp_undo_cwr(tp, 1);
+               tcp_undo_cwr(sk, 1);
                tp->undo_marker = 0;
                NET_INC_STATS_BH(LINUX_MIB_TCPDSACKUNDO);
        }
@@ -1728,10 +1817,10 @@ static int tcp_try_undo_partial(struct sock *sk, struct tcp_sock *tp,
                if (tp->retrans_out == 0)
                        tp->retrans_stamp = 0;
 
-               tcp_update_reordering(tp, tcp_fackets_out(tp)+acked, 1);
+               tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1);
 
                DBGUNDO(sk, tp, "Hoe");
-               tcp_undo_cwr(tp, 0);
+               tcp_undo_cwr(sk, 0);
                NET_INC_STATS_BH(LINUX_MIB_TCPPARTIALUNDO);
 
                /* So... Do not make Hoe's retransmit yet.
@@ -1751,27 +1840,29 @@ static int tcp_try_undo_loss(struct sock *sk, struct tcp_sock *tp)
                sk_stream_for_retrans_queue(skb, sk) {
                        TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
                }
+
+               clear_all_retrans_hints(tp);
+
                DBGUNDO(sk, tp, "partial loss");
                tp->lost_out = 0;
                tp->left_out = tp->sacked_out;
-               tcp_undo_cwr(tp, 1);
+               tcp_undo_cwr(sk, 1);
                NET_INC_STATS_BH(LINUX_MIB_TCPLOSSUNDO);
-               tp->retransmits = 0;
+               inet_csk(sk)->icsk_retransmits = 0;
                tp->undo_marker = 0;
                if (!IsReno(tp))
-                       tcp_set_ca_state(tp, TCP_CA_Open);
+                       tcp_set_ca_state(sk, TCP_CA_Open);
                return 1;
        }
        return 0;
 }
 
-static inline void tcp_complete_cwr(struct tcp_sock *tp)
+static inline void tcp_complete_cwr(struct sock *sk)
 {
-       if (tcp_westwood_cwnd(tp)) 
-               tp->snd_ssthresh = tp->snd_cwnd;
-       else
-               tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
+       struct tcp_sock *tp = tcp_sk(sk);
+       tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
        tp->snd_cwnd_stamp = tcp_time_stamp;
+       tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR);
 }
 
 static void tcp_try_to_open(struct sock *sk, struct tcp_sock *tp, int flag)
@@ -1782,24 +1873,52 @@ static void tcp_try_to_open(struct sock *sk, struct tcp_sock *tp, int flag)
                tp->retrans_stamp = 0;
 
        if (flag&FLAG_ECE)
-               tcp_enter_cwr(tp);
+               tcp_enter_cwr(sk);
 
-       if (tp->ca_state != TCP_CA_CWR) {
+       if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) {
                int state = TCP_CA_Open;
 
                if (tp->left_out || tp->retrans_out || tp->undo_marker)
                        state = TCP_CA_Disorder;
 
-               if (tp->ca_state != state) {
-                       tcp_set_ca_state(tp, state);
+               if (inet_csk(sk)->icsk_ca_state != state) {
+                       tcp_set_ca_state(sk, state);
                        tp->high_seq = tp->snd_nxt;
                }
                tcp_moderate_cwnd(tp);
        } else {
-               tcp_cwnd_down(tp);
+               tcp_cwnd_down(sk);
        }
 }
 
+static void tcp_mtup_probe_failed(struct sock *sk)
+{
+       struct inet_connection_sock *icsk = inet_csk(sk);
+
+       icsk->icsk_mtup.search_high = icsk->icsk_mtup.probe_size - 1;
+       icsk->icsk_mtup.probe_size = 0;
+}
+
+static void tcp_mtup_probe_success(struct sock *sk, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+
+       /* FIXME: breaks with very large cwnd */
+       tp->prior_ssthresh = tcp_current_ssthresh(sk);
+       tp->snd_cwnd = tp->snd_cwnd *
+                      tcp_mss_to_mtu(sk, tp->mss_cache) /
+                      icsk->icsk_mtup.probe_size;
+       tp->snd_cwnd_cnt = 0;
+       tp->snd_cwnd_stamp = tcp_time_stamp;
+       tp->rcv_ssthresh = tcp_current_ssthresh(sk);
+
+       icsk->icsk_mtup.search_low = icsk->icsk_mtup.probe_size;
+       icsk->icsk_mtup.probe_size = 0;
+       tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
+}
+
+
 /* Process an event, which can update packets-in-flight not trivially.
  * Main goal of this function is to calculate new estimate for left_out,
  * taking into account both packets sitting in receiver's buffer and
@@ -1815,6 +1934,7 @@ static void
 tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                      int prior_packets, int flag)
 {
+       struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        int is_dupack = (tp->snd_una == prior_snd_una && !(flag&FLAG_NOT_DUP));
 
@@ -1832,13 +1952,13 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                tp->prior_ssthresh = 0;
 
        /* B. In all the states check for reneging SACKs. */
-       if (tp->sacked_out && tcp_check_sack_reneging(sk, tp))
+       if (tp->sacked_out && tcp_check_sack_reneging(sk))
                return;
 
        /* C. Process data loss notification, provided it is valid. */
        if ((flag&FLAG_DATA_LOST) &&
            before(tp->snd_una, tp->high_seq) &&
-           tp->ca_state != TCP_CA_Open &&
+           icsk->icsk_ca_state != TCP_CA_Open &&
            tp->fackets_out > tp->reordering) {
                tcp_mark_head_lost(sk, tp, tp->fackets_out-tp->reordering, tp->high_seq);
                NET_INC_STATS_BH(LINUX_MIB_TCPLOSS);
@@ -1849,14 +1969,14 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
 
        /* E. Check state exit conditions. State can be terminated
         *    when high_seq is ACKed. */
-       if (tp->ca_state == TCP_CA_Open) {
+       if (icsk->icsk_ca_state == TCP_CA_Open) {
                if (!sysctl_tcp_frto)
                        BUG_TRAP(tp->retrans_out == 0);
                tp->retrans_stamp = 0;
        } else if (!before(tp->snd_una, tp->high_seq)) {
-               switch (tp->ca_state) {
+               switch (icsk->icsk_ca_state) {
                case TCP_CA_Loss:
-                       tp->retransmits = 0;
+                       icsk->icsk_retransmits = 0;
                        if (tcp_try_undo_recovery(sk, tp))
                                return;
                        break;
@@ -1865,8 +1985,8 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                        /* CWR is to be held something *above* high_seq
                         * is ACKed for CWR bit to reach receiver. */
                        if (tp->snd_una != tp->high_seq) {
-                               tcp_complete_cwr(tp);
-                               tcp_set_ca_state(tp, TCP_CA_Open);
+                               tcp_complete_cwr(sk);
+                               tcp_set_ca_state(sk, TCP_CA_Open);
                        }
                        break;
 
@@ -1877,7 +1997,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                             * catching for all duplicate ACKs. */
                            IsReno(tp) || tp->snd_una != tp->high_seq) {
                                tp->undo_marker = 0;
-                               tcp_set_ca_state(tp, TCP_CA_Open);
+                               tcp_set_ca_state(sk, TCP_CA_Open);
                        }
                        break;
 
@@ -1886,17 +2006,17 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                                tcp_reset_reno_sack(tp);
                        if (tcp_try_undo_recovery(sk, tp))
                                return;
-                       tcp_complete_cwr(tp);
+                       tcp_complete_cwr(sk);
                        break;
                }
        }
 
        /* F. Process state. */
-       switch (tp->ca_state) {
+       switch (icsk->icsk_ca_state) {
        case TCP_CA_Recovery:
                if (prior_snd_una == tp->snd_una) {
                        if (IsReno(tp) && is_dupack)
-                               tcp_add_reno_sack(tp);
+                               tcp_add_reno_sack(sk);
                } else {
                        int acked = prior_packets - tp->packets_out;
                        if (IsReno(tp))
@@ -1906,13 +2026,13 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                break;
        case TCP_CA_Loss:
                if (flag&FLAG_DATA_ACKED)
-                       tp->retransmits = 0;
+                       icsk->icsk_retransmits = 0;
                if (!tcp_try_undo_loss(sk, tp)) {
                        tcp_moderate_cwnd(tp);
                        tcp_xmit_retransmit_queue(sk);
                        return;
                }
-               if (tp->ca_state != TCP_CA_Open)
+               if (icsk->icsk_ca_state != TCP_CA_Open)
                        return;
                /* Loss is undone; fall through to processing in Open state. */
        default:
@@ -1920,10 +2040,10 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                        if (tp->snd_una != prior_snd_una)
                                tcp_reset_reno_sack(tp);
                        if (is_dupack)
-                               tcp_add_reno_sack(tp);
+                               tcp_add_reno_sack(sk);
                }
 
-               if (tp->ca_state == TCP_CA_Disorder)
+               if (icsk->icsk_ca_state == TCP_CA_Disorder)
                        tcp_try_undo_dsack(sk, tp);
 
                if (!tcp_time_to_recover(sk, tp)) {
@@ -1931,6 +2051,17 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                        return;
                }
 
+               /* MTU probe failure: don't reduce cwnd */
+               if (icsk->icsk_ca_state < TCP_CA_CWR &&
+                   icsk->icsk_mtup.probe_size &&
+                   tp->snd_una == tp->mtu_probe.probe_seq_start) {
+                       tcp_mtup_probe_failed(sk);
+                       /* Restores the reduction we did in tcp_mtup_probe() */
+                       tp->snd_cwnd++;
+                       tcp_simple_retransmit(sk);
+                       return;
+               }
+
                /* Otherwise enter Recovery state */
 
                if (IsReno(tp))
@@ -1943,30 +2074,29 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                tp->undo_marker = tp->snd_una;
                tp->undo_retrans = tp->retrans_out;
 
-               if (tp->ca_state < TCP_CA_CWR) {
+               if (icsk->icsk_ca_state < TCP_CA_CWR) {
                        if (!(flag&FLAG_ECE))
-                               tp->prior_ssthresh = tcp_current_ssthresh(tp);
-                       tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+                               tp->prior_ssthresh = tcp_current_ssthresh(sk);
+                       tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);
                        TCP_ECN_queue_cwr(tp);
                }
 
+               tp->bytes_acked = 0;
                tp->snd_cwnd_cnt = 0;
-               tcp_set_ca_state(tp, TCP_CA_Recovery);
+               tcp_set_ca_state(sk, TCP_CA_Recovery);
        }
 
        if (is_dupack || tcp_head_timedout(sk, tp))
                tcp_update_scoreboard(sk, tp);
-       tcp_cwnd_down(tp);
+       tcp_cwnd_down(sk);
        tcp_xmit_retransmit_queue(sk);
 }
 
 /* Read draft-ietf-tcplw-high-performance before mucking
- * with this code. (Superceeds RFC1323)
+ * with this code. (Supersedes RFC1323)
  */
-static void tcp_ack_saw_tstamp(struct tcp_sock *tp, int flag)
+static void tcp_ack_saw_tstamp(struct sock *sk, int flag)
 {
-       __u32 seq_rtt;
-
        /* RTTM Rule: A TSecr value received in a segment is used to
         * update the averaged RTT measurement only if the segment
         * acknowledges some new data, i.e., only if it advances the
@@ -1976,20 +2106,21 @@ static void tcp_ack_saw_tstamp(struct tcp_sock *tp, int flag)
         * 1998/04/10 Andrey V. Savochkin <saw@msu.ru>
         *
         * Changed: reset backoff as soon as we see the first valid sample.
-        * If we do not, we get strongly overstimated rto. With timestamps
+        * If we do not, we get strongly overestimated rto. With timestamps
         * samples are accepted even from very old segments: f.e., when rtt=1
         * increases to 8, we retransmit 5 times and after 8 seconds delayed
         * answer arrives rto becomes 120 seconds! If at least one of segments
         * in window is lost... Voila.                          --ANK (010210)
         */
-       seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
-       tcp_rtt_estimator(tp, seq_rtt);
-       tcp_set_rto(tp);
-       tp->backoff = 0;
-       tcp_bound_rto(tp);
+       struct tcp_sock *tp = tcp_sk(sk);
+       const __u32 seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+       tcp_rtt_estimator(sk, seq_rtt);
+       tcp_set_rto(sk);
+       inet_csk(sk)->icsk_backoff = 0;
+       tcp_bound_rto(sk);
 }
 
-static void tcp_ack_no_tstamp(struct tcp_sock *tp, u32 seq_rtt, int flag)
+static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, int flag)
 {
        /* We don't have a timestamp. Can only use
         * packets that are not retransmitted to determine
@@ -2003,360 +2134,44 @@ static void tcp_ack_no_tstamp(struct tcp_sock *tp, u32 seq_rtt, int flag)
        if (flag & FLAG_RETRANS_DATA_ACKED)
                return;
 
-       tcp_rtt_estimator(tp, seq_rtt);
-       tcp_set_rto(tp);
-       tp->backoff = 0;
-       tcp_bound_rto(tp);
+       tcp_rtt_estimator(sk, seq_rtt);
+       tcp_set_rto(sk);
+       inet_csk(sk)->icsk_backoff = 0;
+       tcp_bound_rto(sk);
 }
 
-static inline void tcp_ack_update_rtt(struct tcp_sock *tp,
-                                     int flag, s32 seq_rtt)
+static inline void tcp_ack_update_rtt(struct sock *sk, const int flag,
+                                     const s32 seq_rtt)
 {
+       const struct tcp_sock *tp = tcp_sk(sk);
        /* Note that peer MAY send zero echo. In this case it is ignored. (rfc1323) */
        if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
-               tcp_ack_saw_tstamp(tp, flag);
+               tcp_ack_saw_tstamp(sk, flag);
        else if (seq_rtt >= 0)
-               tcp_ack_no_tstamp(tp, seq_rtt, flag);
+               tcp_ack_no_tstamp(sk, seq_rtt, flag);
 }
 
-/*
- * Compute congestion window to use.
- *
- * This is from the implementation of BICTCP in
- * Lison-Xu, Kahaled Harfoush, and Injog Rhee.
- *  "Binary Increase Congestion Control for Fast, Long Distance
- *  Networks" in InfoComm 2004
- * Available from:
- *  http://www.csc.ncsu.edu/faculty/rhee/export/bitcp.pdf
- *
- * Unless BIC is enabled and congestion window is large
- * this behaves the same as the original Reno.
- */
-static inline __u32 bictcp_cwnd(struct tcp_sock *tp)
+static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
+                          u32 in_flight, int good)
 {
-       /* orignal Reno behaviour */
-       if (!tcp_is_bic(tp))
-               return tp->snd_cwnd;
-
-       if (tp->bictcp.last_cwnd == tp->snd_cwnd &&
-          (s32)(tcp_time_stamp - tp->bictcp.last_stamp) <= (HZ>>5))
-               return tp->bictcp.cnt;
-
-       tp->bictcp.last_cwnd = tp->snd_cwnd;
-       tp->bictcp.last_stamp = tcp_time_stamp;
-      
-       /* start off normal */
-       if (tp->snd_cwnd <= sysctl_tcp_bic_low_window)
-               tp->bictcp.cnt = tp->snd_cwnd;
-
-       /* binary increase */
-       else if (tp->snd_cwnd < tp->bictcp.last_max_cwnd) {
-               __u32   dist = (tp->bictcp.last_max_cwnd - tp->snd_cwnd)
-                       / BICTCP_B;
-
-               if (dist > BICTCP_MAX_INCREMENT)
-                       /* linear increase */
-                       tp->bictcp.cnt = tp->snd_cwnd / BICTCP_MAX_INCREMENT;
-               else if (dist <= 1U)
-                       /* binary search increase */
-                       tp->bictcp.cnt = tp->snd_cwnd * BICTCP_FUNC_OF_MIN_INCR
-                               / BICTCP_B;
-               else
-                       /* binary search increase */
-                       tp->bictcp.cnt = tp->snd_cwnd / dist;
-       } else {
-               /* slow start amd linear increase */
-               if (tp->snd_cwnd < tp->bictcp.last_max_cwnd + BICTCP_B)
-                       /* slow start */
-                       tp->bictcp.cnt = tp->snd_cwnd * BICTCP_FUNC_OF_MIN_INCR
-                               / BICTCP_B;
-               else if (tp->snd_cwnd < tp->bictcp.last_max_cwnd
-                                       + BICTCP_MAX_INCREMENT*(BICTCP_B-1))
-                       /* slow start */
-                       tp->bictcp.cnt = tp->snd_cwnd * (BICTCP_B-1)
-                               / (tp->snd_cwnd-tp->bictcp.last_max_cwnd);
-               else
-                       /* linear increase */
-                       tp->bictcp.cnt = tp->snd_cwnd / BICTCP_MAX_INCREMENT;
-       }
-       return tp->bictcp.cnt;
-}
-
-/* This is Jacobson's slow start and congestion avoidance. 
- * SIGCOMM '88, p. 328.
- */
-static inline void reno_cong_avoid(struct tcp_sock *tp)
-{
-        if (tp->snd_cwnd <= tp->snd_ssthresh) {
-                /* In "safe" area, increase. */
-               if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                       tp->snd_cwnd++;
-       } else {
-                /* In dangerous area, increase slowly.
-                * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
-                */
-               if (tp->snd_cwnd_cnt >= bictcp_cwnd(tp)) {
-                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                               tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt=0;
-               } else
-                       tp->snd_cwnd_cnt++;
-        }
-       tp->snd_cwnd_stamp = tcp_time_stamp;
-}
-
-/* This is based on the congestion detection/avoidance scheme described in
- *    Lawrence S. Brakmo and Larry L. Peterson.
- *    "TCP Vegas: End to end congestion avoidance on a global internet."
- *    IEEE Journal on Selected Areas in Communication, 13(8):1465--1480,
- *    October 1995. Available from:
- *     ftp://ftp.cs.arizona.edu/xkernel/Papers/jsac.ps
- *
- * See http://www.cs.arizona.edu/xkernel/ for their implementation.
- * The main aspects that distinguish this implementation from the
- * Arizona Vegas implementation are:
- *   o We do not change the loss detection or recovery mechanisms of
- *     Linux in any way. Linux already recovers from losses quite well,
- *     using fine-grained timers, NewReno, and FACK.
- *   o To avoid the performance penalty imposed by increasing cwnd
- *     only every-other RTT during slow start, we increase during
- *     every RTT during slow start, just like Reno.
- *   o Largely to allow continuous cwnd growth during slow start,
- *     we use the rate at which ACKs come back as the "actual"
- *     rate, rather than the rate at which data is sent.
- *   o To speed convergence to the right rate, we set the cwnd
- *     to achieve the right ("actual") rate when we exit slow start.
- *   o To filter out the noise caused by delayed ACKs, we use the
- *     minimum RTT sample observed during the last RTT to calculate
- *     the actual rate.
- *   o When the sender re-starts from idle, it waits until it has
- *     received ACKs for an entire flight of new data before making
- *     a cwnd adjustment decision. The original Vegas implementation
- *     assumed senders never went idle.
- */
-static void vegas_cong_avoid(struct tcp_sock *tp, u32 ack, u32 seq_rtt)
-{
-       /* The key players are v_beg_snd_una and v_beg_snd_nxt.
-        *
-        * These are so named because they represent the approximate values
-        * of snd_una and snd_nxt at the beginning of the current RTT. More
-        * precisely, they represent the amount of data sent during the RTT.
-        * At the end of the RTT, when we receive an ACK for v_beg_snd_nxt,
-        * we will calculate that (v_beg_snd_nxt - v_beg_snd_una) outstanding
-        * bytes of data have been ACKed during the course of the RTT, giving
-        * an "actual" rate of:
-        *
-        *     (v_beg_snd_nxt - v_beg_snd_una) / (rtt duration)
-        *
-        * Unfortunately, v_beg_snd_una is not exactly equal to snd_una,
-        * because delayed ACKs can cover more than one segment, so they
-        * don't line up nicely with the boundaries of RTTs.
-        *
-        * Another unfortunate fact of life is that delayed ACKs delay the
-        * advance of the left edge of our send window, so that the number
-        * of bytes we send in an RTT is often less than our cwnd will allow.
-        * So we keep track of our cwnd separately, in v_beg_snd_cwnd.
-        */
-
-       if (after(ack, tp->vegas.beg_snd_nxt)) {
-               /* Do the Vegas once-per-RTT cwnd adjustment. */
-               u32 old_wnd, old_snd_cwnd;
-
-               
-               /* Here old_wnd is essentially the window of data that was
-                * sent during the previous RTT, and has all
-                * been acknowledged in the course of the RTT that ended
-                * with the ACK we just received. Likewise, old_snd_cwnd
-                * is the cwnd during the previous RTT.
-                */
-               old_wnd = (tp->vegas.beg_snd_nxt - tp->vegas.beg_snd_una) /
-                       tp->mss_cache_std;
-               old_snd_cwnd = tp->vegas.beg_snd_cwnd;
-
-               /* Save the extent of the current window so we can use this
-                * at the end of the next RTT.
-                */
-               tp->vegas.beg_snd_una  = tp->vegas.beg_snd_nxt;
-               tp->vegas.beg_snd_nxt  = tp->snd_nxt;
-               tp->vegas.beg_snd_cwnd = tp->snd_cwnd;
-
-               /* Take into account the current RTT sample too, to
-                * decrease the impact of delayed acks. This double counts
-                * this sample since we count it for the next window as well,
-                * but that's not too awful, since we're taking the min,
-                * rather than averaging.
-                */
-               vegas_rtt_calc(tp, seq_rtt);
-
-               /* We do the Vegas calculations only if we got enough RTT
-                * samples that we can be reasonably sure that we got
-                * at least one RTT sample that wasn't from a delayed ACK.
-                * If we only had 2 samples total,
-                * then that means we're getting only 1 ACK per RTT, which
-                * means they're almost certainly delayed ACKs.
-                * If  we have 3 samples, we should be OK.
-                */
-
-               if (tp->vegas.cntRTT <= 2) {
-                       /* We don't have enough RTT samples to do the Vegas
-                        * calculation, so we'll behave like Reno.
-                        */
-                       if (tp->snd_cwnd > tp->snd_ssthresh)
-                               tp->snd_cwnd++;
-               } else {
-                       u32 rtt, target_cwnd, diff;
-
-                       /* We have enough RTT samples, so, using the Vegas
-                        * algorithm, we determine if we should increase or
-                        * decrease cwnd, and by how much.
-                        */
-
-                       /* Pluck out the RTT we are using for the Vegas
-                        * calculations. This is the min RTT seen during the
-                        * last RTT. Taking the min filters out the effects
-                        * of delayed ACKs, at the cost of noticing congestion
-                        * a bit later.
-                        */
-                       rtt = tp->vegas.minRTT;
-
-                       /* Calculate the cwnd we should have, if we weren't
-                        * going too fast.
-                        *
-                        * This is:
-                        *     (actual rate in segments) * baseRTT
-                        * We keep it as a fixed point number with
-                        * V_PARAM_SHIFT bits to the right of the binary point.
-                        */
-                       target_cwnd = ((old_wnd * tp->vegas.baseRTT)
-                                      << V_PARAM_SHIFT) / rtt;
-
-                       /* Calculate the difference between the window we had,
-                        * and the window we would like to have. This quantity
-                        * is the "Diff" from the Arizona Vegas papers.
-                        *
-                        * Again, this is a fixed point number with
-                        * V_PARAM_SHIFT bits to the right of the binary
-                        * point.
-                        */
-                       diff = (old_wnd << V_PARAM_SHIFT) - target_cwnd;
-
-                       if (tp->snd_cwnd < tp->snd_ssthresh) {
-                               /* Slow start.  */
-                               if (diff > sysctl_tcp_vegas_gamma) {
-                                       /* Going too fast. Time to slow down
-                                        * and switch to congestion avoidance.
-                                        */
-                                       tp->snd_ssthresh = 2;
-
-                                       /* Set cwnd to match the actual rate
-                                        * exactly:
-                                        *   cwnd = (actual rate) * baseRTT
-                                        * Then we add 1 because the integer
-                                        * truncation robs us of full link
-                                        * utilization.
-                                        */
-                                       tp->snd_cwnd = min(tp->snd_cwnd,
-                                                          (target_cwnd >>
-                                                           V_PARAM_SHIFT)+1);
-
-                               }
-                       } else {
-                               /* Congestion avoidance. */
-                               u32 next_snd_cwnd;
-
-                               /* Figure out where we would like cwnd
-                                * to be.
-                                */
-                               if (diff > sysctl_tcp_vegas_beta) {
-                                       /* The old window was too fast, so
-                                        * we slow down.
-                                        */
-                                       next_snd_cwnd = old_snd_cwnd - 1;
-                               } else if (diff < sysctl_tcp_vegas_alpha) {
-                                       /* We don't have enough extra packets
-                                        * in the network, so speed up.
-                                        */
-                                       next_snd_cwnd = old_snd_cwnd + 1;
-                               } else {
-                                       /* Sending just as fast as we
-                                        * should be.
-                                        */
-                                       next_snd_cwnd = old_snd_cwnd;
-                               }
-
-                               /* Adjust cwnd upward or downward, toward the
-                                * desired value.
-                                */
-                               if (next_snd_cwnd > tp->snd_cwnd)
-                                       tp->snd_cwnd++;
-                               else if (next_snd_cwnd < tp->snd_cwnd)
-                                       tp->snd_cwnd--;
-                       }
-               }
-
-               /* Wipe the slate clean for the next RTT. */
-               tp->vegas.cntRTT = 0;
-               tp->vegas.minRTT = 0x7fffffff;
-       }
-
-       /* The following code is executed for every ack we receive,
-        * except for conditions checked in should_advance_cwnd()
-        * before the call to tcp_cong_avoid(). Mainly this means that
-        * we only execute this code if the ack actually acked some
-        * data.
-        */
-
-       /* If we are in slow start, increase our cwnd in response to this ACK.
-        * (If we are not in slow start then we are in congestion avoidance,
-        * and adjust our congestion window only once per RTT. See the code
-        * above.)
-        */
-       if (tp->snd_cwnd <= tp->snd_ssthresh) 
-               tp->snd_cwnd++;
-
-       /* to keep cwnd from growing without bound */
-       tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp);
-
-       /* Make sure that we are never so timid as to reduce our cwnd below
-        * 2 MSS.
-        *
-        * Going below 2 MSS would risk huge delayed ACKs from our receiver.
-        */
-       tp->snd_cwnd = max(tp->snd_cwnd, 2U);
-
-       tp->snd_cwnd_stamp = tcp_time_stamp;
-}
-
-static inline void tcp_cong_avoid(struct tcp_sock *tp, u32 ack, u32 seq_rtt)
-{
-       if (tcp_vegas_enabled(tp))
-               vegas_cong_avoid(tp, ack, seq_rtt);
-       else
-               reno_cong_avoid(tp);
+       const struct inet_connection_sock *icsk = inet_csk(sk);
+       icsk->icsk_ca_ops->cong_avoid(sk, ack, rtt, in_flight, good);
+       tcp_sk(sk)->snd_cwnd_stamp = tcp_time_stamp;
 }
 
 /* Restart timer after forward progress on connection.
  * RFC2988 recommends to restart timer to now+rto.
  */
 
-static inline void tcp_ack_packets_out(struct sock *sk, struct tcp_sock *tp)
+static void tcp_ack_packets_out(struct sock *sk, struct tcp_sock *tp)
 {
        if (!tp->packets_out) {
-               tcp_clear_xmit_timer(sk, TCP_TIME_RETRANS);
+               inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
        } else {
-               tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto);
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
        }
 }
 
-/* There is one downside to this scheme.  Although we keep the
- * ACK clock ticking, adjusting packet counters and advancing
- * congestion window, we do not liberate socket send buffer
- * space.
- *
- * Mucking with skb->truesize and sk->sk_wmem_alloc et al.
- * then making a write space wakeup callback is a possible
- * future enhancement.  WARNING: it is not trivial to make.
- */
 static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
                         __u32 now, __s32 *seq_rtt)
 {
@@ -2413,15 +2228,27 @@ static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
        return acked;
 }
 
+static u32 tcp_usrtt(const struct sk_buff *skb)
+{
+       struct timeval tv, now;
+
+       do_gettimeofday(&now);
+       skb_get_timestamp(skb, &tv);
+       return (now.tv_sec - tv.tv_sec) * 1000000 + (now.tv_usec - tv.tv_usec);
+}
 
 /* Remove acknowledged frames from the retransmission queue. */
 static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 {
        struct tcp_sock *tp = tcp_sk(sk);
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        struct sk_buff *skb;
        __u32 now = tcp_time_stamp;
        int acked = 0;
        __s32 seq_rtt = -1;
+       u32 pkts_acked = 0;
+       void (*rtt_sample)(struct sock *sk, u32 usrtt)
+               = icsk->icsk_ca_ops->rtt_sample;
 
        while ((skb = skb_peek(&sk->sk_write_queue)) &&
               skb != sk->sk_send_head) {
@@ -2433,7 +2260,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                 * the other end.
                 */
                if (after(scb->end_seq, tp->snd_una)) {
-                       if (tcp_skb_pcount(skb) > 1)
+                       if (tcp_skb_pcount(skb) > 1 &&
+                           after(tp->snd_una, scb->seq))
                                acked |= tcp_tso_acked(sk, skb,
                                                       now, &seq_rtt);
                        break;
@@ -2448,19 +2276,30 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                 */
                if (!(scb->flags & TCPCB_FLAG_SYN)) {
                        acked |= FLAG_DATA_ACKED;
+                       ++pkts_acked;
                } else {
                        acked |= FLAG_SYN_ACKED;
                        tp->retrans_stamp = 0;
                }
 
+               /* MTU probing checks */
+               if (icsk->icsk_mtup.probe_size) {
+                       if (!after(tp->mtu_probe.probe_seq_end, TCP_SKB_CB(skb)->end_seq)) {
+                               tcp_mtup_probe_success(sk, skb);
+                       }
+               }
+
                if (sacked) {
                        if (sacked & TCPCB_RETRANS) {
                                if(sacked & TCPCB_SACKED_RETRANS)
                                        tp->retrans_out -= tcp_skb_pcount(skb);
                                acked |= FLAG_RETRANS_DATA_ACKED;
                                seq_rtt = -1;
-                       } else if (seq_rtt < 0)
+                       } else if (seq_rtt < 0) {
                                seq_rtt = now - scb->when;
+                               if (rtt_sample)
+                                       (*rtt_sample)(sk, tcp_usrtt(skb));
+                       }
                        if (sacked & TCPCB_SACKED_ACKED)
                                tp->sacked_out -= tcp_skb_pcount(skb);
                        if (sacked & TCPCB_LOST)
@@ -2470,17 +2309,24 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                                    !before(scb->end_seq, tp->snd_up))
                                        tp->urg_mode = 0;
                        }
-               } else if (seq_rtt < 0)
+               } else if (seq_rtt < 0) {
                        seq_rtt = now - scb->when;
+                       if (rtt_sample)
+                               (*rtt_sample)(sk, tcp_usrtt(skb));
+               }
                tcp_dec_pcount_approx(&tp->fackets_out, skb);
                tcp_packets_out_dec(tp, skb);
-               __skb_unlink(skb, skb->list);
+               __skb_unlink(skb, &sk->sk_write_queue);
                sk_stream_free_skb(sk, skb);
+               clear_all_retrans_hints(tp);
        }
 
        if (acked&FLAG_ACKED) {
-               tcp_ack_update_rtt(tp, acked, seq_rtt);
+               tcp_ack_update_rtt(sk, acked, seq_rtt);
                tcp_ack_packets_out(sk, tp);
+
+               if (icsk->icsk_ca_ops->pkts_acked)
+                       icsk->icsk_ca_ops->pkts_acked(sk, pkts_acked);
        }
 
 #if FASTRETRANS_DEBUG > 0
@@ -2488,19 +2334,20 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
        BUG_TRAP((int)tp->lost_out >= 0);
        BUG_TRAP((int)tp->retrans_out >= 0);
        if (!tp->packets_out && tp->rx_opt.sack_ok) {
+               const struct inet_connection_sock *icsk = inet_csk(sk);
                if (tp->lost_out) {
                        printk(KERN_DEBUG "Leak l=%u %d\n",
-                              tp->lost_out, tp->ca_state);
+                              tp->lost_out, icsk->icsk_ca_state);
                        tp->lost_out = 0;
                }
                if (tp->sacked_out) {
                        printk(KERN_DEBUG "Leak s=%u %d\n",
-                              tp->sacked_out, tp->ca_state);
+                              tp->sacked_out, icsk->icsk_ca_state);
                        tp->sacked_out = 0;
                }
                if (tp->retrans_out) {
                        printk(KERN_DEBUG "Leak r=%u %d\n",
-                              tp->retrans_out, tp->ca_state);
+                              tp->retrans_out, icsk->icsk_ca_state);
                        tp->retrans_out = 0;
                }
        }
@@ -2511,40 +2358,43 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 
 static void tcp_ack_probe(struct sock *sk)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
+       const struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
 
        /* Was it a usable window open? */
 
        if (!after(TCP_SKB_CB(sk->sk_send_head)->end_seq,
                   tp->snd_una + tp->snd_wnd)) {
-               tp->backoff = 0;
-               tcp_clear_xmit_timer(sk, TCP_TIME_PROBE0);
+               icsk->icsk_backoff = 0;
+               inet_csk_clear_xmit_timer(sk, ICSK_TIME_PROBE0);
                /* Socket must be waked up by subsequent tcp_data_snd_check().
                 * This function is not for random using!
                 */
        } else {
-               tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0,
-                                    min(tp->rto << tp->backoff, TCP_RTO_MAX));
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
+                                         min(icsk->icsk_rto << icsk->icsk_backoff, TCP_RTO_MAX),
+                                         TCP_RTO_MAX);
        }
 }
 
-static inline int tcp_ack_is_dubious(struct tcp_sock *tp, int flag)
+static inline int tcp_ack_is_dubious(const struct sock *sk, const int flag)
 {
        return (!(flag & FLAG_NOT_DUP) || (flag & FLAG_CA_ALERT) ||
-               tp->ca_state != TCP_CA_Open);
+               inet_csk(sk)->icsk_ca_state != TCP_CA_Open);
 }
 
-static inline int tcp_may_raise_cwnd(struct tcp_sock *tp, int flag)
+static inline int tcp_may_raise_cwnd(const struct sock *sk, const int flag)
 {
+       const struct tcp_sock *tp = tcp_sk(sk);
        return (!(flag & FLAG_ECE) || tp->snd_cwnd < tp->snd_ssthresh) &&
-               !((1<<tp->ca_state)&(TCPF_CA_Recovery|TCPF_CA_CWR));
+               !((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_Recovery | TCPF_CA_CWR));
 }
 
 /* Check that window update is acceptable.
  * The function assumes that snd_una<=ack<=snd_next.
  */
-static inline int tcp_may_update_window(struct tcp_sock *tp, u32 ack,
-                                       u32 ack_seq, u32 nwin)
+static inline int tcp_may_update_window(const struct tcp_sock *tp, const u32 ack,
+                                       const u32 ack_seq, const u32 nwin)
 {
        return (after(ack, tp->snd_una) ||
                after(ack_seq, tp->snd_wl1) ||
@@ -2575,11 +2425,12 @@ static int tcp_ack_update_window(struct sock *sk, struct tcp_sock *tp,
                        /* Note, it is the only place, where
                         * fast path is recovered for sending TCP.
                         */
+                       tp->pred_flags = 0;
                        tcp_fast_path_check(sk, tp);
 
                        if (nwin > tp->max_window) {
                                tp->max_window = nwin;
-                               tcp_sync_mss(sk, tp->pmtu_cookie);
+                               tcp_sync_mss(sk, inet_csk(sk)->icsk_pmtu_cookie);
                        }
                }
        }
@@ -2619,265 +2470,15 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una)
        }
 
        /* F-RTO affects on two new ACKs following RTO.
-        * At latest on third ACK the TCP behavor is back to normal.
+        * At latest on third ACK the TCP behavior is back to normal.
         */
        tp->frto_counter = (tp->frto_counter + 1) % 3;
 }
 
-/*
- * TCP Westwood+
- */
-
-/*
- * @init_westwood
- * This function initializes fields used in TCP Westwood+. We can't
- * get no information about RTTmin at this time so we simply set it to
- * TCP_WESTWOOD_INIT_RTT. This value was chosen to be too conservative
- * since in this way we're sure it will be updated in a consistent
- * way as soon as possible. It will reasonably happen within the first
- * RTT period of the connection lifetime.
- */
-
-static void init_westwood(struct sock *sk)
-{
-        struct tcp_sock *tp = tcp_sk(sk);
-
-        tp->westwood.bw_ns_est = 0;
-        tp->westwood.bw_est = 0;
-        tp->westwood.accounted = 0;
-        tp->westwood.cumul_ack = 0;
-        tp->westwood.rtt_win_sx = tcp_time_stamp;
-        tp->westwood.rtt = TCP_WESTWOOD_INIT_RTT;
-        tp->westwood.rtt_min = TCP_WESTWOOD_INIT_RTT;
-        tp->westwood.snd_una = tp->snd_una;
-}
-
-/*
- * @westwood_do_filter
- * Low-pass filter. Implemented using constant coeffients.
- */
-
-static inline __u32 westwood_do_filter(__u32 a, __u32 b)
-{
-       return (((7 * a) + b) >> 3);
-}
-
-static void westwood_filter(struct sock *sk, __u32 delta)
-{
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       tp->westwood.bw_ns_est =
-               westwood_do_filter(tp->westwood.bw_ns_est, 
-                                  tp->westwood.bk / delta);
-       tp->westwood.bw_est =
-               westwood_do_filter(tp->westwood.bw_est,
-                                  tp->westwood.bw_ns_est);
-}
-
-/* 
- * @westwood_update_rttmin
- * It is used to update RTTmin. In this case we MUST NOT use
- * WESTWOOD_RTT_MIN minimum bound since we could be on a LAN!
- */
-
-static inline __u32 westwood_update_rttmin(const struct sock *sk)
-{
-       const struct tcp_sock *tp = tcp_sk(sk);
-       __u32 rttmin = tp->westwood.rtt_min;
-
-       if (tp->westwood.rtt != 0 &&
-           (tp->westwood.rtt < tp->westwood.rtt_min || !rttmin))
-               rttmin = tp->westwood.rtt;
-
-       return rttmin;
-}
-
-/*
- * @westwood_acked
- * Evaluate increases for dk. 
- */
-
-static inline __u32 westwood_acked(const struct sock *sk)
-{
-       const struct tcp_sock *tp = tcp_sk(sk);
-
-       return tp->snd_una - tp->westwood.snd_una;
-}
-
-/*
- * @westwood_new_window
- * It evaluates if we are receiving data inside the same RTT window as
- * when we started.
- * Return value:
- * It returns 0 if we are still evaluating samples in the same RTT
- * window, 1 if the sample has to be considered in the next window.
- */
-
-static int westwood_new_window(const struct sock *sk)
-{
-       const struct tcp_sock *tp = tcp_sk(sk);
-       __u32 left_bound;
-       __u32 rtt;
-       int ret = 0;
-
-       left_bound = tp->westwood.rtt_win_sx;
-       rtt = max(tp->westwood.rtt, (u32) TCP_WESTWOOD_RTT_MIN);
-
-       /*
-        * A RTT-window has passed. Be careful since if RTT is less than
-        * 50ms we don't filter but we continue 'building the sample'.
-        * This minimum limit was choosen since an estimation on small
-        * time intervals is better to avoid...
-        * Obvioulsy on a LAN we reasonably will always have
-        * right_bound = left_bound + WESTWOOD_RTT_MIN
-         */
-
-       if ((left_bound + rtt) < tcp_time_stamp)
-               ret = 1;
-
-       return ret;
-}
-
-/*
- * @westwood_update_window
- * It updates RTT evaluation window if it is the right moment to do
- * it. If so it calls filter for evaluating bandwidth. 
- */
-
-static void __westwood_update_window(struct sock *sk, __u32 now)
-{
-       struct tcp_sock *tp = tcp_sk(sk);
-       __u32 delta = now - tp->westwood.rtt_win_sx;
-
-        if (delta) {
-               if (tp->westwood.rtt)
-                       westwood_filter(sk, delta);
-
-               tp->westwood.bk = 0;
-               tp->westwood.rtt_win_sx = tcp_time_stamp;
-       }
-}
-
-
-static void westwood_update_window(struct sock *sk, __u32 now)
-{
-       if (westwood_new_window(sk)) 
-               __westwood_update_window(sk, now);
-}
-
-/*
- * @__tcp_westwood_fast_bw
- * It is called when we are in fast path. In particular it is called when
- * header prediction is successfull. In such case infact update is
- * straight forward and doesn't need any particular care.
- */
-
-static void __tcp_westwood_fast_bw(struct sock *sk, struct sk_buff *skb)
-{
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       westwood_update_window(sk, tcp_time_stamp);
-
-       tp->westwood.bk += westwood_acked(sk);
-       tp->westwood.snd_una = tp->snd_una;
-       tp->westwood.rtt_min = westwood_update_rttmin(sk);
-}
-
-static inline void tcp_westwood_fast_bw(struct sock *sk, struct sk_buff *skb)
-{
-        if (tcp_is_westwood(tcp_sk(sk)))
-                __tcp_westwood_fast_bw(sk, skb);
-}
-
-
-/*
- * @westwood_dupack_update
- * It updates accounted and cumul_ack when receiving a dupack.
- */
-
-static void westwood_dupack_update(struct sock *sk)
-{
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       tp->westwood.accounted += tp->mss_cache_std;
-       tp->westwood.cumul_ack = tp->mss_cache_std;
-}
-
-static inline int westwood_may_change_cumul(struct tcp_sock *tp)
-{
-       return (tp->westwood.cumul_ack > tp->mss_cache_std);
-}
-
-static inline void westwood_partial_update(struct tcp_sock *tp)
-{
-       tp->westwood.accounted -= tp->westwood.cumul_ack;
-       tp->westwood.cumul_ack = tp->mss_cache_std;
-}
-
-static inline void westwood_complete_update(struct tcp_sock *tp)
-{
-       tp->westwood.cumul_ack -= tp->westwood.accounted;
-       tp->westwood.accounted = 0;
-}
-
-/*
- * @westwood_acked_count
- * This function evaluates cumul_ack for evaluating dk in case of
- * delayed or partial acks.
- */
-
-static inline __u32 westwood_acked_count(struct sock *sk)
-{
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       tp->westwood.cumul_ack = westwood_acked(sk);
-
-        /* If cumul_ack is 0 this is a dupack since it's not moving
-         * tp->snd_una.
-         */
-        if (!(tp->westwood.cumul_ack))
-                westwood_dupack_update(sk);
-
-        if (westwood_may_change_cumul(tp)) {
-               /* Partial or delayed ack */
-               if (tp->westwood.accounted >= tp->westwood.cumul_ack)
-                       westwood_partial_update(tp);
-               else
-                       westwood_complete_update(tp);
-       }
-
-       tp->westwood.snd_una = tp->snd_una;
-
-       return tp->westwood.cumul_ack;
-}
-
-
-/*
- * @__tcp_westwood_slow_bw
- * It is called when something is going wrong..even if there could
- * be no problems! Infact a simple delayed packet may trigger a
- * dupack. But we need to be careful in such case.
- */
-
-static void __tcp_westwood_slow_bw(struct sock *sk, struct sk_buff *skb)
-{
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       westwood_update_window(sk, tcp_time_stamp);
-
-       tp->westwood.bk += westwood_acked_count(sk);
-       tp->westwood.rtt_min = westwood_update_rttmin(sk);
-}
-
-static inline void tcp_westwood_slow_bw(struct sock *sk, struct sk_buff *skb)
-{
-        if (tcp_is_westwood(tcp_sk(sk)))
-                __tcp_westwood_slow_bw(sk, skb);
-}
-
 /* This routine deals with incoming acks, but not outgoing ones. */
 static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
 {
+       struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        u32 prior_snd_una = tp->snd_una;
        u32 ack_seq = TCP_SKB_CB(skb)->seq;
@@ -2895,6 +2496,9 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
        if (before(ack, prior_snd_una))
                goto old_ack;
 
+       if (sysctl_tcp_abc && icsk->icsk_ca_state < TCP_CA_CWR)
+               tp->bytes_acked += ack - prior_snd_una;
+
        if (!(flag&FLAG_SLOWPATH) && after(ack, prior_snd_una)) {
                /* Window is constant, pure forward advance.
                 * No more checks are required.
@@ -2902,9 +2506,10 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
                 */
                tcp_update_wl(tp, ack, ack_seq);
                tp->snd_una = ack;
-               tcp_westwood_fast_bw(sk, skb);
                flag |= FLAG_WIN_UPDATE;
 
+               tcp_ca_event(sk, CA_EVENT_FAST_ACK);
+
                NET_INC_STATS_BH(LINUX_MIB_TCPHPACKS);
        } else {
                if (ack_seq != TCP_SKB_CB(skb)->end_seq)
@@ -2920,7 +2525,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
                if (TCP_ECN_rcv_ecn_echo(tp, skb->h.th))
                        flag |= FLAG_ECE;
 
-               tcp_westwood_slow_bw(sk,skb);
+               tcp_ca_event(sk, CA_EVENT_SLOW_ACK);
        }
 
        /* We passed data and got it acked, remove any soft error
@@ -2940,17 +2545,14 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
        if (tp->frto_counter)
                tcp_process_frto(sk, prior_snd_una);
 
-       if (tcp_ack_is_dubious(tp, flag)) {
-               /* Advanve CWND, if state allows this. */
-               if ((flag & FLAG_DATA_ACKED) &&
-                   (tcp_vegas_enabled(tp) || prior_in_flight >= tp->snd_cwnd) &&
-                   tcp_may_raise_cwnd(tp, flag))
-                       tcp_cong_avoid(tp, ack, seq_rtt);
+       if (tcp_ack_is_dubious(sk, flag)) {
+               /* Advance CWND, if state allows this. */
+               if ((flag & FLAG_DATA_ACKED) && tcp_may_raise_cwnd(sk, flag))
+                       tcp_cong_avoid(sk, ack,  seq_rtt, prior_in_flight, 0);
                tcp_fastretrans_alert(sk, prior_snd_una, prior_packets, flag);
        } else {
-               if ((flag & FLAG_DATA_ACKED) && 
-                   (tcp_vegas_enabled(tp) || prior_in_flight >= tp->snd_cwnd))
-                       tcp_cong_avoid(tp, ack, seq_rtt);
+               if ((flag & FLAG_DATA_ACKED))
+                       tcp_cong_avoid(sk, ack, seq_rtt, prior_in_flight, 1);
        }
 
        if ((flag & FLAG_FORWARD_PROGRESS) || !(flag&FLAG_NOT_DUP))
@@ -2959,7 +2561,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
        return 1;
 
 no_queue:
-       tp->probes_out = 0;
+       icsk->icsk_probes_out = 0;
 
        /* If this ack opens up a zero window, clear backoff.  It was
         * being used to time the probes, and is probably far higher than
@@ -3069,8 +2671,8 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
 /* Fast parse options. This hopes to only see timestamps.
  * If it is wrong it falls back on tcp_parse_options().
  */
-static inline int tcp_fast_parse_options(struct sk_buff *skb, struct tcphdr *th,
-                                        struct tcp_sock *tp)
+static int tcp_fast_parse_options(struct sk_buff *skb, struct tcphdr *th,
+                                 struct tcp_sock *tp)
 {
        if (th->doff == sizeof(struct tcphdr)>>2) {
                tp->rx_opt.saw_tstamp = 0;
@@ -3137,8 +2739,9 @@ static inline void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
  * up to bandwidth of 18Gigabit/sec. 8) ]
  */
 
-static int tcp_disordered_ack(struct tcp_sock *tp, struct sk_buff *skb)
+static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        struct tcphdr *th = skb->h.th;
        u32 seq = TCP_SKB_CB(skb)->seq;
        u32 ack = TCP_SKB_CB(skb)->ack_seq;
@@ -3153,14 +2756,15 @@ static int tcp_disordered_ack(struct tcp_sock *tp, struct sk_buff *skb)
                !tcp_may_update_window(tp, ack, seq, ntohs(th->window) << tp->rx_opt.snd_wscale) &&
 
                /* 4. ... and sits in replay window. */
-               (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (tp->rto*1024)/HZ);
+               (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (inet_csk(sk)->icsk_rto * 1024) / HZ);
 }
 
-static inline int tcp_paws_discard(struct tcp_sock *tp, struct sk_buff *skb)
+static inline int tcp_paws_discard(const struct sock *sk, const struct sk_buff *skb)
 {
+       const struct tcp_sock *tp = tcp_sk(sk);
        return ((s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) > TCP_PAWS_WINDOW &&
                xtime.tv_sec < tp->rx_opt.ts_recent_stamp + TCP_PAWS_24DAYS &&
-               !tcp_disordered_ack(tp, skb));
+               !tcp_disordered_ack(sk, skb));
 }
 
 /* Check segment sequence number for validity.
@@ -3223,7 +2827,7 @@ static void tcp_fin(struct sk_buff *skb, struct sock *sk, struct tcphdr *th)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
-       tcp_schedule_ack(tp);
+       inet_csk_schedule_ack(sk);
 
        sk->sk_shutdown |= RCV_SHUTDOWN;
        sock_set_flag(sk, SOCK_DONE);
@@ -3233,7 +2837,7 @@ static void tcp_fin(struct sk_buff *skb, struct sock *sk, struct tcphdr *th)
                case TCP_ESTABLISHED:
                        /* Move to CLOSE_WAIT */
                        tcp_set_state(sk, TCP_CLOSE_WAIT);
-                       tp->ack.pingpong = 1;
+                       inet_csk(sk)->icsk_ack.pingpong = 1;
                        break;
 
                case TCP_CLOSE_WAIT:
@@ -3288,8 +2892,7 @@ static void tcp_fin(struct sk_buff *skb, struct sock *sk, struct tcphdr *th)
        }
 }
 
-static __inline__ int
-tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, u32 end_seq)
+static inline int tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, u32 end_seq)
 {
        if (!after(seq, sp->end_seq) && !after(sp->start_seq, end_seq)) {
                if (before(seq, sp->start_seq))
@@ -3301,7 +2904,7 @@ tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, u32 end_seq)
        return 0;
 }
 
-static inline void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq)
+static void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq)
 {
        if (tp->rx_opt.sack_ok && sysctl_tcp_dsack) {
                if (before(seq, tp->rcv_nxt))
@@ -3316,7 +2919,7 @@ static inline void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq)
        }
 }
 
-static inline void tcp_dsack_extend(struct tcp_sock *tp, u32 seq, u32 end_seq)
+static void tcp_dsack_extend(struct tcp_sock *tp, u32 seq, u32 end_seq)
 {
        if (!tp->rx_opt.dsack)
                tcp_dsack_set(tp, seq, end_seq);
@@ -3331,7 +2934,7 @@ static void tcp_send_dupack(struct sock *sk, struct sk_buff *skb)
        if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq &&
            before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
                NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOST);
-               tcp_enter_quickack_mode(tp);
+               tcp_enter_quickack_mode(sk);
 
                if (tp->rx_opt.sack_ok && sysctl_tcp_dsack) {
                        u32 end_seq = TCP_SKB_CB(skb)->end_seq;
@@ -3374,7 +2977,7 @@ static void tcp_sack_maybe_coalesce(struct tcp_sock *tp)
        }
 }
 
-static __inline__ void tcp_sack_swap(struct tcp_sack_block *sack1, struct tcp_sack_block *sack2)
+static inline void tcp_sack_swap(struct tcp_sack_block *sack1, struct tcp_sack_block *sack2)
 {
        __u32 tmp;
 
@@ -3439,7 +3042,7 @@ static void tcp_sack_remove(struct tcp_sock *tp)
        int this_sack;
 
        /* Empty ofo queue, hence, all the SACKs are eaten. Clear. */
-       if (skb_queue_len(&tp->out_of_order_queue) == 0) {
+       if (skb_queue_empty(&tp->out_of_order_queue)) {
                tp->rx_opt.num_sacks = 0;
                tp->rx_opt.eff_sacks = tp->rx_opt.dsack;
                return;
@@ -3490,7 +3093,7 @@ static void tcp_ofo_queue(struct sock *sk)
 
                if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
                        SOCK_DEBUG(sk, "ofo packet was already received \n");
-                       __skb_unlink(skb, skb->list);
+                       __skb_unlink(skb, &tp->out_of_order_queue);
                        __kfree_skb(skb);
                        continue;
                }
@@ -3498,7 +3101,7 @@ static void tcp_ofo_queue(struct sock *sk)
                           tp->rcv_nxt, TCP_SKB_CB(skb)->seq,
                           TCP_SKB_CB(skb)->end_seq);
 
-               __skb_unlink(skb, skb->list);
+               __skb_unlink(skb, &tp->out_of_order_queue);
                __skb_queue_tail(&sk->sk_receive_queue, skb);
                tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
                if(skb->h.th->fin)
@@ -3572,14 +3175,14 @@ queue_and_out:
                if(th->fin)
                        tcp_fin(skb, sk, th);
 
-               if (skb_queue_len(&tp->out_of_order_queue)) {
+               if (!skb_queue_empty(&tp->out_of_order_queue)) {
                        tcp_ofo_queue(sk);
 
                        /* RFC2581. 4.2. SHOULD send immediate ACK, when
                         * gap in queue is filled.
                         */
-                       if (!skb_queue_len(&tp->out_of_order_queue))
-                               tp->ack.pingpong = 0;
+                       if (skb_queue_empty(&tp->out_of_order_queue))
+                               inet_csk(sk)->icsk_ack.pingpong = 0;
                }
 
                if (tp->rx_opt.num_sacks)
@@ -3600,8 +3203,8 @@ queue_and_out:
                tcp_dsack_set(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
 
 out_of_window:
-               tcp_enter_quickack_mode(tp);
-               tcp_schedule_ack(tp);
+               tcp_enter_quickack_mode(sk);
+               inet_csk_schedule_ack(sk);
 drop:
                __kfree_skb(skb);
                return;
@@ -3611,7 +3214,7 @@ drop:
        if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt + tcp_receive_window(tp)))
                goto out_of_window;
 
-       tcp_enter_quickack_mode(tp);
+       tcp_enter_quickack_mode(sk);
 
        if (before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
                /* Partial packet, seq < rcv_next < end_seq */
@@ -3640,7 +3243,7 @@ drop:
 
        /* Disable header prediction. */
        tp->pred_flags = 0;
-       tcp_schedule_ack(tp);
+       inet_csk_schedule_ack(sk);
 
        SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n",
                   tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
@@ -3664,7 +3267,7 @@ drop:
                u32 end_seq = TCP_SKB_CB(skb)->end_seq;
 
                if (seq == TCP_SKB_CB(skb1)->end_seq) {
-                       __skb_append(skb1, skb);
+                       __skb_append(skb1, skb, &tp->out_of_order_queue);
 
                        if (!tp->rx_opt.num_sacks ||
                            tp->selective_acks[0].end_seq != seq)
@@ -3708,7 +3311,7 @@ drop:
                               tcp_dsack_extend(tp, TCP_SKB_CB(skb1)->seq, end_seq);
                               break;
                       }
-                      __skb_unlink(skb1, skb1->list);
+                      __skb_unlink(skb1, &tp->out_of_order_queue);
                       tcp_dsack_extend(tp, TCP_SKB_CB(skb1)->seq, TCP_SKB_CB(skb1)->end_seq);
                       __kfree_skb(skb1);
                }
@@ -3725,18 +3328,19 @@ add_sack:
  * simplifies code)
  */
 static void
-tcp_collapse(struct sock *sk, struct sk_buff *head,
-            struct sk_buff *tail, u32 start, u32 end)
+tcp_collapse(struct sock *sk, struct sk_buff_head *list,
+            struct sk_buff *head, struct sk_buff *tail,
+            u32 start, u32 end)
 {
        struct sk_buff *skb;
 
-       /* First, check that queue is collapsable and find
+       /* First, check that queue is collapsible and find
         * the point where collapsing can be useful. */
        for (skb = head; skb != tail; ) {
                /* No new bits? It is possible on ofo queue. */
                if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
                        struct sk_buff *next = skb->next;
-                       __skb_unlink(skb, skb->list);
+                       __skb_unlink(skb, list);
                        __kfree_skb(skb);
                        NET_INC_STATS_BH(LINUX_MIB_TCPRCVCOLLAPSED);
                        skb = next;
@@ -3782,7 +3386,7 @@ tcp_collapse(struct sock *sk, struct sk_buff *head,
                nskb->mac.raw = nskb->head + (skb->mac.raw-skb->head);
                memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
                TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start;
-               __skb_insert(nskb, skb->prev, skb, skb->list);
+               __skb_insert(nskb, skb->prev, skb, list);
                sk_stream_set_owner_r(nskb, sk);
 
                /* Copy data, releasing collapsed skbs. */
@@ -3790,7 +3394,7 @@ tcp_collapse(struct sock *sk, struct sk_buff *head,
                        int offset = start - TCP_SKB_CB(skb)->seq;
                        int size = TCP_SKB_CB(skb)->end_seq - start;
 
-                       if (offset < 0) BUG();
+                       BUG_ON(offset < 0);
                        if (size > 0) {
                                size = min(copy, size);
                                if (skb_copy_bits(skb, offset, skb_put(nskb, size), size))
@@ -3801,7 +3405,7 @@ tcp_collapse(struct sock *sk, struct sk_buff *head,
                        }
                        if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
                                struct sk_buff *next = skb->next;
-                               __skb_unlink(skb, skb->list);
+                               __skb_unlink(skb, list);
                                __kfree_skb(skb);
                                NET_INC_STATS_BH(LINUX_MIB_TCPRCVCOLLAPSED);
                                skb = next;
@@ -3837,7 +3441,8 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
                if (skb == (struct sk_buff *)&tp->out_of_order_queue ||
                    after(TCP_SKB_CB(skb)->seq, end) ||
                    before(TCP_SKB_CB(skb)->end_seq, start)) {
-                       tcp_collapse(sk, head, skb, start, end);
+                       tcp_collapse(sk, &tp->out_of_order_queue,
+                                    head, skb, start, end);
                        head = skb;
                        if (skb == (struct sk_buff *)&tp->out_of_order_queue)
                                break;
@@ -3874,7 +3479,8 @@ static int tcp_prune_queue(struct sock *sk)
                tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
 
        tcp_collapse_ofo_queue(sk);
-       tcp_collapse(sk, sk->sk_receive_queue.next,
+       tcp_collapse(sk, &sk->sk_receive_queue,
+                    sk->sk_receive_queue.next,
                     (struct sk_buff*)&sk->sk_receive_queue,
                     tp->copied_seq, tp->rcv_nxt);
        sk_stream_mem_reclaim(sk);
@@ -3886,9 +3492,8 @@ static int tcp_prune_queue(struct sock *sk)
         * This must not ever occur. */
 
        /* First, purge the out_of_order queue. */
-       if (skb_queue_len(&tp->out_of_order_queue)) {
-               NET_ADD_STATS_BH(LINUX_MIB_OFOPRUNED, 
-                                skb_queue_len(&tp->out_of_order_queue));
+       if (!skb_queue_empty(&tp->out_of_order_queue)) {
+               NET_INC_STATS_BH(LINUX_MIB_OFOPRUNED);
                __skb_queue_purge(&tp->out_of_order_queue);
 
                /* Reset SACK state.  A conforming SACK implementation will
@@ -3915,6 +3520,7 @@ static int tcp_prune_queue(struct sock *sk)
        return -1;
 }
 
+EXPORT_SYMBOL_GPL(tcp_cwnd_application_limited);
 
 /* RFC2861, slow part. Adjust cwnd, after it was not full during one rto.
  * As additional protections, we do not touch cwnd in retransmission phases,
@@ -3924,12 +3530,12 @@ void tcp_cwnd_application_limited(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
-       if (tp->ca_state == TCP_CA_Open &&
+       if (inet_csk(sk)->icsk_ca_state == TCP_CA_Open &&
            sk->sk_socket && !test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
                /* Limited by application or receiver window. */
                u32 win_used = max(tp->snd_cwnd_used, 2U);
                if (win_used < tp->snd_cwnd) {
-                       tp->snd_ssthresh = tcp_current_ssthresh(tp);
+                       tp->snd_ssthresh = tcp_current_ssthresh(sk);
                        tp->snd_cwnd = (tp->snd_cwnd + win_used) >> 1;
                }
                tp->snd_cwnd_used = 0;
@@ -3937,6 +3543,28 @@ void tcp_cwnd_application_limited(struct sock *sk)
        tp->snd_cwnd_stamp = tcp_time_stamp;
 }
 
+static int tcp_should_expand_sndbuf(struct sock *sk, struct tcp_sock *tp)
+{
+       /* If the user specified a specific send buffer setting, do
+        * not modify it.
+        */
+       if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+               return 0;
+
+       /* If we are under global TCP memory pressure, do not expand.  */
+       if (tcp_memory_pressure)
+               return 0;
+
+       /* If we are under soft global TCP memory pressure, do not expand.  */
+       if (atomic_read(&tcp_memory_allocated) >= sysctl_tcp_mem[0])
+               return 0;
+
+       /* If we filled the congestion window, do not expand.  */
+       if (tp->packets_out >= tp->snd_cwnd)
+               return 0;
+
+       return 1;
+}
 
 /* When incoming ACK allowed to free some skb from write_queue,
  * we remember this event in flag SOCK_QUEUE_SHRUNK and wake up socket
@@ -3948,11 +3576,8 @@ static void tcp_new_space(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
-       if (tp->packets_out < tp->snd_cwnd &&
-           !(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&
-           !tcp_memory_pressure &&
-           atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
-               int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache_std) +
+       if (tcp_should_expand_sndbuf(sk, tp)) {
+               int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) +
                        MAX_TCP_HEADER + 16 + sizeof(struct sk_buff),
                    demanded = max_t(unsigned int, tp->snd_cwnd,
                                                   tp->reordering + 1);
@@ -3965,7 +3590,7 @@ static void tcp_new_space(struct sock *sk)
        sk->sk_write_space(sk);
 }
 
-static inline void tcp_check_space(struct sock *sk)
+static void tcp_check_space(struct sock *sk)
 {
        if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) {
                sock_reset_flag(sk, SOCK_QUEUE_SHRUNK);
@@ -3975,22 +3600,9 @@ static inline void tcp_check_space(struct sock *sk)
        }
 }
 
-static void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)
+static inline void tcp_data_snd_check(struct sock *sk, struct tcp_sock *tp)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||
-           tcp_packets_in_flight(tp) >= tp->snd_cwnd ||
-           tcp_write_xmit(sk, tp->nonagle))
-               tcp_check_probe_timer(sk, tp);
-}
-
-static __inline__ void tcp_data_snd_check(struct sock *sk)
-{
-       struct sk_buff *skb = sk->sk_send_head;
-
-       if (skb != NULL)
-               __tcp_data_snd_check(sk, skb);
+       tcp_push_pending_frames(sk, tp);
        tcp_check_space(sk);
 }
 
@@ -4002,13 +3614,13 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
        struct tcp_sock *tp = tcp_sk(sk);
 
            /* More than one full frame received... */
-       if (((tp->rcv_nxt - tp->rcv_wup) > tp->ack.rcv_mss
+       if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss
             /* ... and right edge of window advances far enough.
              * (tcp_recvmsg() will send ACK otherwise). Or...
              */
             && __tcp_select_window(sk) >= tp->rcv_wnd) ||
            /* We ACK each frame or... */
-           tcp_in_quickack_mode(tp) ||
+           tcp_in_quickack_mode(sk) ||
            /* We have out of order data. */
            (ofo_possible &&
             skb_peek(&tp->out_of_order_queue))) {
@@ -4020,10 +3632,9 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
        }
 }
 
-static __inline__ void tcp_ack_snd_check(struct sock *sk)
+static inline void tcp_ack_snd_check(struct sock *sk)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
-       if (!tcp_ack_scheduled(tp)) {
+       if (!inet_csk_ack_scheduled(sk)) {
                /* We sent a data segment already. */
                return;
        }
@@ -4032,7 +3643,7 @@ static __inline__ void tcp_ack_snd_check(struct sock *sk)
 
 /*
  *     This routine is only called when we have urgent data
- *     signalled. Its the 'slow' part of tcp_urg. It could be
+ *     signaled. Its the 'slow' part of tcp_urg. It could be
  *     moved inline now as tcp_urg is only called from one
  *     place. We handle URGent data wrong. We have to - as
  *     BSD still doesn't use the correction from RFC961.
@@ -4077,7 +3688,7 @@ static void tcp_check_urg(struct sock * sk, struct tcphdr * th)
         * urgent. To do this requires some care. We cannot just ignore
         * tp->copied_seq since we would read the last urgent byte again
         * as data, nor can we alter copied_seq until this data arrives
-        * or we break the sematics of SIOCATMARK (and thus sockatmark())
+        * or we break the semantics of SIOCATMARK (and thus sockatmark())
         *
         * NOTE. Double Dutch. Rendering to plain English: author of comment
         * above did something sort of  send("A", MSG_OOB); send("B", MSG_OOB);
@@ -4094,7 +3705,7 @@ static void tcp_check_urg(struct sock * sk, struct tcphdr * th)
                struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
                tp->copied_seq++;
                if (skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)) {
-                       __skb_unlink(skb, skb->list);
+                       __skb_unlink(skb, &sk->sk_receive_queue);
                        __kfree_skb(skb);
                }
        }
@@ -4169,8 +3780,7 @@ static int __tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb)
        return result;
 }
 
-static __inline__ int
-tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb)
+static inline int tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb)
 {
        return skb->ip_summed != CHECKSUM_UNNECESSARY &&
                __tcp_checksum_complete_user(sk, skb);
@@ -4222,7 +3832,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
        tp->rx_opt.saw_tstamp = 0;
 
        /*      pred_flags is 0xS?10 << 16 + snd_wnd
-        *      if header_predition is to be made
+        *      if header_prediction is to be made
         *      'S' will always be tp->tcp_header_len >> 2
         *      '?' will be 0 for the fast path, otherwise pred_flags is 0 to
         *  turn it off (when there are holes in the receive 
@@ -4277,14 +3887,14 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                                    tp->rcv_nxt == tp->rcv_wup)
                                        tcp_store_ts_recent(tp);
 
-                               tcp_rcv_rtt_measure_ts(tp, skb);
+                               tcp_rcv_rtt_measure_ts(sk, skb);
 
                                /* We know that such packets are checksummed
                                 * on entry.
                                 */
                                tcp_ack(sk, skb, 0);
                                __kfree_skb(skb); 
-                               tcp_data_snd_check(sk);
+                               tcp_data_snd_check(sk, tp);
                                return 0;
                        } else { /* Header too small */
                                TCP_INC_STATS_BH(TCP_MIB_INERRS);
@@ -4310,7 +3920,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                                            tp->rcv_nxt == tp->rcv_wup)
                                                tcp_store_ts_recent(tp);
 
-                                       tcp_rcv_rtt_measure_ts(tp, skb);
+                                       tcp_rcv_rtt_measure_ts(sk, skb);
 
                                        __skb_pull(skb, tcp_header_len);
                                        tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
@@ -4331,7 +3941,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                                    tp->rcv_nxt == tp->rcv_wup)
                                        tcp_store_ts_recent(tp);
 
-                               tcp_rcv_rtt_measure_ts(tp, skb);
+                               tcp_rcv_rtt_measure_ts(sk, skb);
 
                                if ((int)skb->truesize > sk->sk_forward_alloc)
                                        goto step5;
@@ -4350,8 +3960,8 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                        if (TCP_SKB_CB(skb)->ack_seq != tp->snd_una) {
                                /* Well, only one small jumplet in fast path... */
                                tcp_ack(sk, skb, FLAG_DATA);
-                               tcp_data_snd_check(sk);
-                               if (!tcp_ack_scheduled(tp))
+                               tcp_data_snd_check(sk, tp);
+                               if (!inet_csk_ack_scheduled(sk))
                                        goto no_ack;
                        }
 
@@ -4373,7 +3983,7 @@ slow_path:
         * RFC1323: H1. Apply PAWS check first.
         */
        if (tcp_fast_parse_options(skb, th, tp) && tp->rx_opt.saw_tstamp &&
-           tcp_paws_discard(tp, skb)) {
+           tcp_paws_discard(sk, skb)) {
                if (!th->rst) {
                        NET_INC_STATS_BH(LINUX_MIB_PAWSESTABREJECTED);
                        tcp_send_dupack(sk, skb);
@@ -4420,7 +4030,7 @@ step5:
        if(th->ack)
                tcp_ack(sk, skb, FLAG_SLOWPATH);
 
-       tcp_rcv_rtt_measure_ts(tp, skb);
+       tcp_rcv_rtt_measure_ts(sk, skb);
 
        /* Process urgent data. */
        tcp_urg(sk, skb, th);
@@ -4428,7 +4038,7 @@ step5:
        /* step 7: process the segment text */
        tcp_data_queue(sk, skb);
 
-       tcp_data_snd_check(sk);
+       tcp_data_snd_check(sk, tp);
        tcp_ack_snd_check(sk);
        return 0;
 
@@ -4444,6 +4054,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                                         struct tcphdr *th, unsigned len)
 {
        struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
        int saved_clamp = tp->rx_opt.mss_clamp;
 
        tcp_parse_options(skb, &tp->rx_opt, 0);
@@ -4537,7 +4148,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                if (tp->rx_opt.sack_ok && sysctl_tcp_fack)
                        tp->rx_opt.sack_ok |= 2;
 
-               tcp_sync_mss(sk, tp->pmtu_cookie);
+               tcp_mtup_init(sk);
+               tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
                tcp_initialize_rcv_mss(sk);
 
                /* Remember, tcp_poll() does not lock socket!
@@ -4548,10 +4160,12 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                tcp_set_state(sk, TCP_ESTABLISHED);
 
                /* Make sure socket is routed, for correct metrics.  */
-               tp->af_specific->rebuild_header(sk);
+               icsk->icsk_af_ops->rebuild_header(sk);
 
                tcp_init_metrics(sk);
 
+               tcp_init_congestion_control(sk);
+
                /* Prevent spurious tcp_cwnd_restart() on first data
                 * packet.
                 */
@@ -4560,7 +4174,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                tcp_init_buffer_space(sk);
 
                if (sock_flag(sk, SOCK_KEEPOPEN))
-                       tcp_reset_keepalive_timer(sk, keepalive_time_when(tp));
+                       inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp));
 
                if (!tp->rx_opt.snd_wscale)
                        __tcp_fast_path_on(tp, tp->snd_wnd);
@@ -4572,7 +4186,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                        sk_wake_async(sk, 0, POLL_OUT);
                }
 
-               if (sk->sk_write_pending || tp->defer_accept || tp->ack.pingpong) {
+               if (sk->sk_write_pending ||
+                   icsk->icsk_accept_queue.rskq_defer_accept ||
+                   icsk->icsk_ack.pingpong) {
                        /* Save one ACK. Data will be ready after
                         * several ticks, if write_pending is set.
                         *
@@ -4580,12 +4196,13 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                         * look so _wonderfully_ clever, that I was not able
                         * to stand against the temptation 8)     --ANK
                         */
-                       tcp_schedule_ack(tp);
-                       tp->ack.lrcvtime = tcp_time_stamp;
-                       tp->ack.ato      = TCP_ATO_MIN;
-                       tcp_incr_quickack(tp);
-                       tcp_enter_quickack_mode(tp);
-                       tcp_reset_xmit_timer(sk, TCP_TIME_DACK, TCP_DELACK_MAX);
+                       inet_csk_schedule_ack(sk);
+                       icsk->icsk_ack.lrcvtime = tcp_time_stamp;
+                       icsk->icsk_ack.ato       = TCP_ATO_MIN;
+                       tcp_incr_quickack(sk);
+                       tcp_enter_quickack_mode(sk);
+                       inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
+                                                 TCP_DELACK_MAX, TCP_RTO_MAX);
 
 discard:
                        __kfree_skb(skb);
@@ -4642,7 +4259,8 @@ discard:
                if (tp->ecn_flags&TCP_ECN_OK)
                        sock_set_flag(sk, SOCK_NO_LARGESEND);
 
-               tcp_sync_mss(sk, tp->pmtu_cookie);
+               tcp_mtup_init(sk);
+               tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
                tcp_initialize_rcv_mss(sk);
 
 
@@ -4689,6 +4307,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                          struct tcphdr *th, unsigned len)
 {
        struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
        int queued = 0;
 
        tp->rx_opt.saw_tstamp = 0;
@@ -4705,12 +4324,9 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                        goto discard;
 
                if(th->syn) {
-                       if(tp->af_specific->conn_request(sk, skb) < 0)
+                       if (icsk->icsk_af_ops->conn_request(sk, skb) < 0)
                                return 1;
 
-                       init_westwood(sk);
-                       init_bictcp(tp);
-
                        /* Now we have several options: In theory there is 
                         * nothing else in the frame. KA9Q has an option to 
                         * send data with the syn, BSD accepts data with the
@@ -4732,9 +4348,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                goto discard;
 
        case TCP_SYN_SENT:
-               init_westwood(sk);
-               init_bictcp(tp);
-
                queued = tcp_rcv_synsent_state_process(sk, skb, th, len);
                if (queued >= 0)
                        return queued;
@@ -4742,12 +4355,12 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                /* Do step6 onward by hand. */
                tcp_urg(sk, skb, th);
                __kfree_skb(skb);
-               tcp_data_snd_check(sk);
+               tcp_data_snd_check(sk, tp);
                return 0;
        }
 
        if (tcp_fast_parse_options(skb, th, tp) && tp->rx_opt.saw_tstamp &&
-           tcp_paws_discard(tp, skb)) {
+           tcp_paws_discard(sk, skb)) {
                if (!th->rst) {
                        NET_INC_STATS_BH(LINUX_MIB_PAWSESTABREJECTED);
                        tcp_send_dupack(sk, skb);
@@ -4816,7 +4429,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                                 */
                                if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
                                    !tp->srtt)
-                                       tcp_ack_saw_tstamp(tp, 0);
+                                       tcp_ack_saw_tstamp(sk, 0);
 
                                if (tp->rx_opt.tstamp_ok)
                                        tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
@@ -4824,15 +4437,18 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                                /* Make sure socket is routed, for
                                 * correct metrics.
                                 */
-                               tp->af_specific->rebuild_header(sk);
+                               icsk->icsk_af_ops->rebuild_header(sk);
 
                                tcp_init_metrics(sk);
 
+                               tcp_init_congestion_control(sk);
+
                                /* Prevent spurious tcp_cwnd_restart() on
                                 * first data packet.
                                 */
                                tp->lsndtime = tcp_time_stamp;
 
+                               tcp_mtup_init(sk);
                                tcp_initialize_rcv_mss(sk);
                                tcp_init_buffer_space(sk);
                                tcp_fast_path_on(tp);
@@ -4861,9 +4477,9 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                                                return 1;
                                        }
 
-                                       tmo = tcp_fin_time(tp);
+                                       tmo = tcp_fin_time(sk);
                                        if (tmo > TCP_TIMEWAIT_LEN) {
-                                               tcp_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
+                                               inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
                                        } else if (th->fin || sock_owned_by_user(sk)) {
                                                /* Bad case. We could lose such FIN otherwise.
                                                 * It is not a big problem, but it looks confusing
@@ -4871,7 +4487,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                                                 * if it spins in bh_lock_sock(), but it is really
                                                 * marginal case.
                                                 */
-                                               tcp_reset_keepalive_timer(sk, tmo);
+                                               inet_csk_reset_keepalive_timer(sk, tmo);
                                        } else {
                                                tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
                                                goto discard;
@@ -4931,7 +4547,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 
        /* tcp_data could move socket to TIME-WAIT */
        if (sk->sk_state != TCP_CLOSE) {
-               tcp_data_snd_check(sk);
+               tcp_data_snd_check(sk, tp);
                tcp_ack_snd_check(sk);
        }
 
@@ -4947,3 +4563,4 @@ EXPORT_SYMBOL(sysctl_tcp_reordering);
 EXPORT_SYMBOL(tcp_parse_options);
 EXPORT_SYMBOL(tcp_rcv_established);
 EXPORT_SYMBOL(tcp_rcv_state_process);
+EXPORT_SYMBOL(tcp_initialize_rcv_mss);