[INET]: Consolidate xxx_frag_create()
[safe/jmp/linux-2.6] / net / ipv4 / tcp_output.c
index fd3ce38..324b420 100644 (file)
 
 #include <linux/compiler.h>
 #include <linux/module.h>
-#include <linux/smp_lock.h>
 
 /* People can turn this off for buggy TCP's found in printers etc. */
-int sysctl_tcp_retrans_collapse = 1;
+int sysctl_tcp_retrans_collapse __read_mostly = 1;
+
+/* People can turn this on to  work with those rare, broken TCPs that
+ * interpret the window field as a signed quantity.
+ */
+int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
 
 /* This limits the percentage of the congestion window which we
  * will allow a single TSO frame to consume.  Building TSO frames
  * which are too large can cause TCP streams to be bursty.
  */
-int sysctl_tcp_tso_win_divisor = 3;
+int sysctl_tcp_tso_win_divisor __read_mostly = 3;
+
+int sysctl_tcp_mtu_probing __read_mostly = 0;
+int sysctl_tcp_base_mss __read_mostly = 512;
+
+/* By default, RFC2861 behavior.  */
+int sysctl_tcp_slow_start_after_idle __read_mostly = 1;
+
+static inline void tcp_packets_out_inc(struct sock *sk,
+                                      const struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       int orig = tp->packets_out;
 
-static inline void update_send_head(struct sock *sk, struct tcp_sock *tp,
-                                   struct sk_buff *skb)
+       tp->packets_out += tcp_skb_pcount(skb);
+       if (!orig)
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+                                         inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
+}
+
+static void update_send_head(struct sock *sk, struct sk_buff *skb)
 {
-       sk->sk_send_head = skb->next;
-       if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
-               sk->sk_send_head = NULL;
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       tcp_advance_send_head(sk, skb);
        tp->snd_nxt = TCP_SKB_CB(skb)->end_seq;
-       tcp_packets_out_inc(sk, tp, skb);
+       tcp_packets_out_inc(sk, skb);
 }
 
 /* SND.NXT, if window was not shrunk.
@@ -67,8 +88,10 @@ static inline void update_send_head(struct sock *sk, struct tcp_sock *tp,
  * Anything in between SND.UNA...SND.UNA+SND.WND also can be already
  * invalid. OK, let's make this for now:
  */
-static inline __u32 tcp_acceptable_seq(struct sock *sk, struct tcp_sock *tp)
+static inline __u32 tcp_acceptable_seq(struct sock *sk)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
+
        if (!before(tp->snd_una+tp->snd_wnd, tp->snd_nxt))
                return tp->snd_nxt;
        else
@@ -105,47 +128,48 @@ static __u16 tcp_advertise_mss(struct sock *sk)
 
 /* RFC2861. Reset CWND after idle period longer RTO to "restart window".
  * This is the first part of cwnd validation mechanism. */
-static void tcp_cwnd_restart(struct tcp_sock *tp, struct dst_entry *dst)
+static void tcp_cwnd_restart(struct sock *sk, struct dst_entry *dst)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        s32 delta = tcp_time_stamp - tp->lsndtime;
        u32 restart_cwnd = tcp_init_cwnd(tp, dst);
        u32 cwnd = tp->snd_cwnd;
 
-       tcp_ca_event(tp, CA_EVENT_CWND_RESTART);
+       tcp_ca_event(sk, CA_EVENT_CWND_RESTART);
 
-       tp->snd_ssthresh = tcp_current_ssthresh(tp);
+       tp->snd_ssthresh = tcp_current_ssthresh(sk);
        restart_cwnd = min(restart_cwnd, cwnd);
 
-       while ((delta -= tp->rto) > 0 && cwnd > restart_cwnd)
+       while ((delta -= inet_csk(sk)->icsk_rto) > 0 && cwnd > restart_cwnd)
                cwnd >>= 1;
        tp->snd_cwnd = max(cwnd, restart_cwnd);
        tp->snd_cwnd_stamp = tcp_time_stamp;
        tp->snd_cwnd_used = 0;
 }
 
-static inline void tcp_event_data_sent(struct tcp_sock *tp,
-                                      struct sk_buff *skb, struct sock *sk)
+static void tcp_event_data_sent(struct tcp_sock *tp,
+                               struct sk_buff *skb, struct sock *sk)
 {
-       u32 now = tcp_time_stamp;
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       const u32 now = tcp_time_stamp;
 
-       if (!tp->packets_out && (s32)(now - tp->lsndtime) > tp->rto)
-               tcp_cwnd_restart(tp, __sk_dst_get(sk));
+       if (sysctl_tcp_slow_start_after_idle &&
+           (!tp->packets_out && (s32)(now - tp->lsndtime) > icsk->icsk_rto))
+               tcp_cwnd_restart(sk, __sk_dst_get(sk));
 
        tp->lsndtime = now;
 
        /* If it is a reply for ato after last received
         * packet, enter pingpong mode.
         */
-       if ((u32)(now - tp->ack.lrcvtime) < tp->ack.ato)
-               tp->ack.pingpong = 1;
+       if ((u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato)
+               icsk->icsk_ack.pingpong = 1;
 }
 
-static __inline__ void tcp_event_ack_sent(struct sock *sk, unsigned int pkts)
+static inline void tcp_event_ack_sent(struct sock *sk, unsigned int pkts)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       tcp_dec_quickack_mode(tp, pkts);
-       tcp_clear_xmit_timer(sk, TCP_TIME_DACK);
+       tcp_dec_quickack_mode(sk, pkts);
+       inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 }
 
 /* Determine a window scaling and initial window to offer.
@@ -171,18 +195,25 @@ void tcp_select_initial_window(int __space, __u32 mss,
                space = (space / mss) * mss;
 
        /* NOTE: offering an initial window larger than 32767
-        * will break some buggy TCP stacks. We try to be nice.
-        * If we are not window scaling, then this truncates
-        * our initial window offering to 32k. There should also
-        * be a sysctl option to stop being nice.
+        * will break some buggy TCP stacks. If the admin tells us
+        * it is likely we could be speaking with such a buggy stack
+        * we will truncate our initial window offering to 32K-1
+        * unless the remote has sent us a window scaling option,
+        * which we interpret as a sign the remote TCP is not
+        * misinterpreting the window field as a signed quantity.
         */
-       (*rcv_wnd) = min(space, MAX_TCP_WINDOW);
+       if (sysctl_tcp_workaround_signed_windows)
+               (*rcv_wnd) = min(space, MAX_TCP_WINDOW);
+       else
+               (*rcv_wnd) = space;
+
        (*rcv_wscale) = 0;
        if (wscale_ok) {
                /* Set window scaling on max possible window
-                * See RFC1323 for an explanation of the limit to 14 
+                * See RFC1323 for an explanation of the limit to 14
                 */
                space = max_t(u32, sysctl_tcp_rmem[2], sysctl_rmem_max);
+               space = min_t(u32, space, *window_clamp);
                while (space > 65535 && (*rcv_wscale) < 14) {
                        space >>= 1;
                        (*rcv_wscale)++;
@@ -190,7 +221,7 @@ void tcp_select_initial_window(int __space, __u32 mss,
        }
 
        /* Set initial window to value enough for senders,
-        * following RFC1414. Senders, not following this RFC,
+        * following RFC2414. Senders, not following this RFC,
         * will be satisfied with 2.
         */
        if (mss > (1<<*rcv_wscale)) {
@@ -212,14 +243,14 @@ void tcp_select_initial_window(int __space, __u32 mss,
  * value can be stuffed directly into th->window for an outgoing
  * frame.
  */
-static __inline__ u16 tcp_select_window(struct sock *sk)
+static u16 tcp_select_window(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        u32 cur_win = tcp_receive_window(tp);
        u32 new_win = __tcp_select_window(sk);
 
        /* Never shrink the offered window */
-       if(new_win < cur_win) {
+       if (new_win < cur_win) {
                /* Danger Will Robinson!
                 * Don't update rcv_wup/rcv_wnd here or else
                 * we will not be able to advertise a zero
@@ -235,7 +266,7 @@ static __inline__ u16 tcp_select_window(struct sock *sk)
        /* Make sure we do not exceed the maximum possible
         * scaled window.
         */
-       if (!tp->rx_opt.rcv_wscale)
+       if (!tp->rx_opt.rcv_wscale && sysctl_tcp_workaround_signed_windows)
                new_win = min(new_win, MAX_TCP_WINDOW);
        else
                new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale));
@@ -250,6 +281,163 @@ static __inline__ u16 tcp_select_window(struct sock *sk)
        return new_win;
 }
 
+static inline void TCP_ECN_send_synack(struct tcp_sock *tp,
+                                      struct sk_buff *skb)
+{
+       TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_CWR;
+       if (!(tp->ecn_flags&TCP_ECN_OK))
+               TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_ECE;
+}
+
+static inline void TCP_ECN_send_syn(struct sock *sk, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       tp->ecn_flags = 0;
+       if (sysctl_tcp_ecn) {
+               TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_ECE|TCPCB_FLAG_CWR;
+               tp->ecn_flags = TCP_ECN_OK;
+       }
+}
+
+static __inline__ void
+TCP_ECN_make_synack(struct request_sock *req, struct tcphdr *th)
+{
+       if (inet_rsk(req)->ecn_ok)
+               th->ece = 1;
+}
+
+static inline void TCP_ECN_send(struct sock *sk, struct sk_buff *skb,
+                               int tcp_header_len)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       if (tp->ecn_flags & TCP_ECN_OK) {
+               /* Not-retransmitted data segment: set ECT and inject CWR. */
+               if (skb->len != tcp_header_len &&
+                   !before(TCP_SKB_CB(skb)->seq, tp->snd_nxt)) {
+                       INET_ECN_xmit(sk);
+                       if (tp->ecn_flags&TCP_ECN_QUEUE_CWR) {
+                               tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
+                               tcp_hdr(skb)->cwr = 1;
+                               skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
+                       }
+               } else {
+                       /* ACK or retransmitted segment: clear ECT|CE */
+                       INET_ECN_dontxmit(sk);
+               }
+               if (tp->ecn_flags & TCP_ECN_DEMAND_CWR)
+                       tcp_hdr(skb)->ece = 1;
+       }
+}
+
+static void tcp_build_and_update_options(__be32 *ptr, struct tcp_sock *tp,
+                                        __u32 tstamp, __u8 **md5_hash)
+{
+       if (tp->rx_opt.tstamp_ok) {
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_TIMESTAMP << 8) |
+                              TCPOLEN_TIMESTAMP);
+               *ptr++ = htonl(tstamp);
+               *ptr++ = htonl(tp->rx_opt.ts_recent);
+       }
+       if (tp->rx_opt.eff_sacks) {
+               struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks;
+               int this_sack;
+
+               *ptr++ = htonl((TCPOPT_NOP  << 24) |
+                              (TCPOPT_NOP  << 16) |
+                              (TCPOPT_SACK <<  8) |
+                              (TCPOLEN_SACK_BASE + (tp->rx_opt.eff_sacks *
+                                                    TCPOLEN_SACK_PERBLOCK)));
+
+               for (this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) {
+                       *ptr++ = htonl(sp[this_sack].start_seq);
+                       *ptr++ = htonl(sp[this_sack].end_seq);
+               }
+
+               if (tp->rx_opt.dsack) {
+                       tp->rx_opt.dsack = 0;
+                       tp->rx_opt.eff_sacks--;
+               }
+       }
+#ifdef CONFIG_TCP_MD5SIG
+       if (md5_hash) {
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_MD5SIG << 8) |
+                              TCPOLEN_MD5SIG);
+               *md5_hash = (__u8 *)ptr;
+       }
+#endif
+}
+
+/* Construct a tcp options header for a SYN or SYN_ACK packet.
+ * If this is every changed make sure to change the definition of
+ * MAX_SYN_SIZE to match the new maximum number of options that you
+ * can generate.
+ *
+ * Note - that with the RFC2385 TCP option, we make room for the
+ * 16 byte MD5 hash. This will be filled in later, so the pointer for the
+ * location to be filled is passed back up.
+ */
+static void tcp_syn_build_options(__be32 *ptr, int mss, int ts, int sack,
+                                 int offer_wscale, int wscale, __u32 tstamp,
+                                 __u32 ts_recent, __u8 **md5_hash)
+{
+       /* We always get an MSS option.
+        * The option bytes which will be seen in normal data
+        * packets should timestamps be used, must be in the MSS
+        * advertised.  But we subtract them from tp->mss_cache so
+        * that calculations in tcp_sendmsg are simpler etc.
+        * So account for this fact here if necessary.  If we
+        * don't do this correctly, as a receiver we won't
+        * recognize data packets as being full sized when we
+        * should, and thus we won't abide by the delayed ACK
+        * rules correctly.
+        * SACKs don't matter, we never delay an ACK when we
+        * have any of those going out.
+        */
+       *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
+       if (ts) {
+               if (sack)
+                       *ptr++ = htonl((TCPOPT_SACK_PERM << 24) |
+                                      (TCPOLEN_SACK_PERM << 16) |
+                                      (TCPOPT_TIMESTAMP << 8) |
+                                      TCPOLEN_TIMESTAMP);
+               else
+                       *ptr++ = htonl((TCPOPT_NOP << 24) |
+                                      (TCPOPT_NOP << 16) |
+                                      (TCPOPT_TIMESTAMP << 8) |
+                                      TCPOLEN_TIMESTAMP);
+               *ptr++ = htonl(tstamp);         /* TSVAL */
+               *ptr++ = htonl(ts_recent);      /* TSECR */
+       } else if (sack)
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_SACK_PERM << 8) |
+                              TCPOLEN_SACK_PERM);
+       if (offer_wscale)
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_WINDOW << 16) |
+                              (TCPOLEN_WINDOW << 8) |
+                              (wscale));
+#ifdef CONFIG_TCP_MD5SIG
+       /*
+        * If MD5 is enabled, then we set the option, and include the size
+        * (always 18). The actual MD5 hash is added just before the
+        * packet is sent.
+        */
+       if (md5_hash) {
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_MD5SIG << 8) |
+                              TCPOLEN_MD5SIG);
+               *md5_hash = (__u8 *) ptr;
+       }
+#endif
+}
 
 /* This routine actually transmits TCP packets queued in by
  * tcp_do_sendmsg().  This is used by both the initial
@@ -262,128 +450,177 @@ static __inline__ u16 tcp_select_window(struct sock *sk)
  * We are working here with either a clone of the original
  * SKB, or a fresh unique copy made by the retransmit engine.
  */
-static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb)
+static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, gfp_t gfp_mask)
 {
-       if (skb != NULL) {
-               struct inet_sock *inet = inet_sk(sk);
-               struct tcp_sock *tp = tcp_sk(sk);
-               struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
-               int tcp_header_size = tp->tcp_header_len;
-               struct tcphdr *th;
-               int sysctl_flags;
-               int err;
+       const struct inet_connection_sock *icsk = inet_csk(sk);
+       struct inet_sock *inet;
+       struct tcp_sock *tp;
+       struct tcp_skb_cb *tcb;
+       int tcp_header_size;
+#ifdef CONFIG_TCP_MD5SIG
+       struct tcp_md5sig_key *md5;
+       __u8 *md5_hash_location;
+#endif
+       struct tcphdr *th;
+       int sysctl_flags;
+       int err;
+
+       BUG_ON(!skb || !tcp_skb_pcount(skb));
+
+       /* If congestion control is doing timestamping, we must
+        * take such a timestamp before we potentially clone/copy.
+        */
+       if (icsk->icsk_ca_ops->flags & TCP_CONG_RTT_STAMP)
+               __net_timestamp(skb);
+
+       if (likely(clone_it)) {
+               if (unlikely(skb_cloned(skb)))
+                       skb = pskb_copy(skb, gfp_mask);
+               else
+                       skb = skb_clone(skb, gfp_mask);
+               if (unlikely(!skb))
+                       return -ENOBUFS;
+       }
 
-               BUG_ON(!tcp_skb_pcount(skb));
+       inet = inet_sk(sk);
+       tp = tcp_sk(sk);
+       tcb = TCP_SKB_CB(skb);
+       tcp_header_size = tp->tcp_header_len;
 
 #define SYSCTL_FLAG_TSTAMPS    0x1
 #define SYSCTL_FLAG_WSCALE     0x2
 #define SYSCTL_FLAG_SACK       0x4
 
-               /* If congestion control is doing timestamping */
-               if (tp->ca_ops->rtt_sample)
-                       do_gettimeofday(&skb->stamp);
-
-               sysctl_flags = 0;
-               if (tcb->flags & TCPCB_FLAG_SYN) {
-                       tcp_header_size = sizeof(struct tcphdr) + TCPOLEN_MSS;
-                       if(sysctl_tcp_timestamps) {
-                               tcp_header_size += TCPOLEN_TSTAMP_ALIGNED;
-                               sysctl_flags |= SYSCTL_FLAG_TSTAMPS;
-                       }
-                       if(sysctl_tcp_window_scaling) {
-                               tcp_header_size += TCPOLEN_WSCALE_ALIGNED;
-                               sysctl_flags |= SYSCTL_FLAG_WSCALE;
-                       }
-                       if(sysctl_tcp_sack) {
-                               sysctl_flags |= SYSCTL_FLAG_SACK;
-                               if(!(sysctl_flags & SYSCTL_FLAG_TSTAMPS))
-                                       tcp_header_size += TCPOLEN_SACKPERM_ALIGNED;
-                       }
-               } else if (tp->rx_opt.eff_sacks) {
-                       /* A SACK is 2 pad bytes, a 2 byte header, plus
-                        * 2 32-bit sequence numbers for each SACK block.
-                        */
-                       tcp_header_size += (TCPOLEN_SACK_BASE_ALIGNED +
-                                           (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK));
+       sysctl_flags = 0;
+       if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
+               tcp_header_size = sizeof(struct tcphdr) + TCPOLEN_MSS;
+               if (sysctl_tcp_timestamps) {
+                       tcp_header_size += TCPOLEN_TSTAMP_ALIGNED;
+                       sysctl_flags |= SYSCTL_FLAG_TSTAMPS;
                }
-               
-               if (tcp_packets_in_flight(tp) == 0)
-                       tcp_ca_event(tp, CA_EVENT_TX_START);
-
-               th = (struct tcphdr *) skb_push(skb, tcp_header_size);
-               skb->h.th = th;
-               skb_set_owner_w(skb, sk);
-
-               /* Build TCP header and checksum it. */
-               th->source              = inet->sport;
-               th->dest                = inet->dport;
-               th->seq                 = htonl(tcb->seq);
-               th->ack_seq             = htonl(tp->rcv_nxt);
-               *(((__u16 *)th) + 6)    = htons(((tcp_header_size >> 2) << 12) | tcb->flags);
-               if (tcb->flags & TCPCB_FLAG_SYN) {
-                       /* RFC1323: The window in SYN & SYN/ACK segments
-                        * is never scaled.
-                        */
-                       th->window      = htons(tp->rcv_wnd);
-               } else {
-                       th->window      = htons(tcp_select_window(sk));
+               if (sysctl_tcp_window_scaling) {
+                       tcp_header_size += TCPOLEN_WSCALE_ALIGNED;
+                       sysctl_flags |= SYSCTL_FLAG_WSCALE;
                }
-               th->check               = 0;
-               th->urg_ptr             = 0;
-
-               if (tp->urg_mode &&
-                   between(tp->snd_up, tcb->seq+1, tcb->seq+0xFFFF)) {
-                       th->urg_ptr             = htons(tp->snd_up-tcb->seq);
-                       th->urg                 = 1;
+               if (sysctl_tcp_sack) {
+                       sysctl_flags |= SYSCTL_FLAG_SACK;
+                       if (!(sysctl_flags & SYSCTL_FLAG_TSTAMPS))
+                               tcp_header_size += TCPOLEN_SACKPERM_ALIGNED;
                }
+       } else if (unlikely(tp->rx_opt.eff_sacks)) {
+               /* A SACK is 2 pad bytes, a 2 byte header, plus
+                * 2 32-bit sequence numbers for each SACK block.
+                */
+               tcp_header_size += (TCPOLEN_SACK_BASE_ALIGNED +
+                                   (tp->rx_opt.eff_sacks *
+                                    TCPOLEN_SACK_PERBLOCK));
+       }
 
-               if (tcb->flags & TCPCB_FLAG_SYN) {
-                       tcp_syn_build_options((__u32 *)(th + 1),
-                                             tcp_advertise_mss(sk),
-                                             (sysctl_flags & SYSCTL_FLAG_TSTAMPS),
-                                             (sysctl_flags & SYSCTL_FLAG_SACK),
-                                             (sysctl_flags & SYSCTL_FLAG_WSCALE),
-                                             tp->rx_opt.rcv_wscale,
-                                             tcb->when,
-                                             tp->rx_opt.ts_recent);
-               } else {
-                       tcp_build_and_update_options((__u32 *)(th + 1),
-                                                    tp, tcb->when);
+       if (tcp_packets_in_flight(tp) == 0)
+               tcp_ca_event(sk, CA_EVENT_TX_START);
 
-                       TCP_ECN_send(sk, tp, skb, tcp_header_size);
-               }
-               tp->af_specific->send_check(sk, th, skb->len, skb);
+#ifdef CONFIG_TCP_MD5SIG
+       /*
+        * Are we doing MD5 on this segment? If so - make
+        * room for it.
+        */
+       md5 = tp->af_specific->md5_lookup(sk, sk);
+       if (md5)
+               tcp_header_size += TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
+       skb_push(skb, tcp_header_size);
+       skb_reset_transport_header(skb);
+       skb_set_owner_w(skb, sk);
+
+       /* Build TCP header and checksum it. */
+       th = tcp_hdr(skb);
+       th->source              = inet->sport;
+       th->dest                = inet->dport;
+       th->seq                 = htonl(tcb->seq);
+       th->ack_seq             = htonl(tp->rcv_nxt);
+       *(((__be16 *)th) + 6)   = htons(((tcp_header_size >> 2) << 12) |
+                                       tcb->flags);
+
+       if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
+               /* RFC1323: The window in SYN & SYN/ACK segments
+                * is never scaled.
+                */
+               th->window      = htons(min(tp->rcv_wnd, 65535U));
+       } else {
+               th->window      = htons(tcp_select_window(sk));
+       }
+       th->check               = 0;
+       th->urg_ptr             = 0;
+
+       if (unlikely(tp->urg_mode &&
+                    between(tp->snd_up, tcb->seq+1, tcb->seq+0xFFFF))) {
+               th->urg_ptr             = htons(tp->snd_up-tcb->seq);
+               th->urg                 = 1;
+       }
+
+       if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
+               tcp_syn_build_options((__be32 *)(th + 1),
+                                     tcp_advertise_mss(sk),
+                                     (sysctl_flags & SYSCTL_FLAG_TSTAMPS),
+                                     (sysctl_flags & SYSCTL_FLAG_SACK),
+                                     (sysctl_flags & SYSCTL_FLAG_WSCALE),
+                                     tp->rx_opt.rcv_wscale,
+                                     tcb->when,
+                                     tp->rx_opt.ts_recent,
+
+#ifdef CONFIG_TCP_MD5SIG
+                                     md5 ? &md5_hash_location :
+#endif
+                                     NULL);
+       } else {
+               tcp_build_and_update_options((__be32 *)(th + 1),
+                                            tp, tcb->when,
+#ifdef CONFIG_TCP_MD5SIG
+                                            md5 ? &md5_hash_location :
+#endif
+                                            NULL);
+               TCP_ECN_send(sk, skb, tcp_header_size);
+       }
+
+#ifdef CONFIG_TCP_MD5SIG
+       /* Calculate the MD5 hash, as we have all we need now */
+       if (md5) {
+               tp->af_specific->calc_md5_hash(md5_hash_location,
+                                              md5,
+                                              sk, NULL, NULL,
+                                              tcp_hdr(skb),
+                                              sk->sk_protocol,
+                                              skb->len);
+       }
+#endif
 
-               if (tcb->flags & TCPCB_FLAG_ACK)
-                       tcp_event_ack_sent(sk, tcp_skb_pcount(skb));
+       icsk->icsk_af_ops->send_check(sk, skb->len, skb);
 
-               if (skb->len != tcp_header_size)
-                       tcp_event_data_sent(tp, skb, sk);
+       if (likely(tcb->flags & TCPCB_FLAG_ACK))
+               tcp_event_ack_sent(sk, tcp_skb_pcount(skb));
 
+       if (skb->len != tcp_header_size)
+               tcp_event_data_sent(tp, skb, sk);
+
+       if (after(tcb->end_seq, tp->snd_nxt) || tcb->seq == tcb->end_seq)
                TCP_INC_STATS(TCP_MIB_OUTSEGS);
 
-               err = tp->af_specific->queue_xmit(skb, 0);
-               if (err <= 0)
-                       return err;
+       err = icsk->icsk_af_ops->queue_xmit(skb, 0);
+       if (likely(err <= 0))
+               return err;
 
-               tcp_enter_cwr(tp);
+       tcp_enter_cwr(sk, 1);
+
+       return net_xmit_eval(err);
 
-               /* NET_XMIT_CN is special. It does not guarantee,
-                * that this packet is lost. It tells that device
-                * is about to start to drop packets or already
-                * drops some packets of the same priority and
-                * invokes us to send less aggressively.
-                */
-               return err == NET_XMIT_CN ? 0 : err;
-       }
-       return -ENOBUFS;
 #undef SYSCTL_FLAG_TSTAMPS
 #undef SYSCTL_FLAG_WSCALE
 #undef SYSCTL_FLAG_SACK
 }
 
 
-/* This routine just queue's the buffer 
+/* This routine just queue's the buffer
  *
  * NOTE: probe0 timer is not checked, do not forget tcp_push_pending_frames,
  * otherwise socket can stall.
@@ -395,47 +632,62 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
        /* Advance write_seq and place onto the write_queue. */
        tp->write_seq = TCP_SKB_CB(skb)->end_seq;
        skb_header_release(skb);
-       __skb_queue_tail(&sk->sk_write_queue, skb);
+       tcp_add_write_queue_tail(sk, skb);
        sk_charge_skb(sk, skb);
-
-       /* Queue it, remembering where we must start sending. */
-       if (sk->sk_send_head == NULL)
-               sk->sk_send_head = skb;
 }
 
-static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb)
+static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb, unsigned int mss_now)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
-
-       if (skb->len <= tp->mss_cache ||
-           !(sk->sk_route_caps & NETIF_F_TSO)) {
+       if (skb->len <= mss_now || !sk_can_gso(sk)) {
                /* Avoid the costly divide in the normal
                 * non-TSO case.
                 */
-               skb_shinfo(skb)->tso_segs = 1;
-               skb_shinfo(skb)->tso_size = 0;
+               skb_shinfo(skb)->gso_segs = 1;
+               skb_shinfo(skb)->gso_size = 0;
+               skb_shinfo(skb)->gso_type = 0;
        } else {
-               unsigned int factor;
-
-               factor = skb->len + (tp->mss_cache - 1);
-               factor /= tp->mss_cache;
-               skb_shinfo(skb)->tso_segs = factor;
-               skb_shinfo(skb)->tso_size = tp->mss_cache;
+               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss_now);
+               skb_shinfo(skb)->gso_size = mss_now;
+               skb_shinfo(skb)->gso_type = sk->sk_gso_type;
        }
 }
 
+/* When a modification to fackets out becomes necessary, we need to check
+ * skb is counted to fackets_out or not. Another important thing is to
+ * tweak SACK fastpath hint too as it would overwrite all changes unless
+ * hint is also changed.
+ */
+static void tcp_adjust_fackets_out(struct tcp_sock *tp, struct sk_buff *skb,
+                                  int decr)
+{
+       if (!tp->sacked_out || tcp_is_reno(tp))
+               return;
+
+       if (!before(tp->highest_sack, TCP_SKB_CB(skb)->seq))
+               tp->fackets_out -= decr;
+
+       /* cnt_hint is "off-by-one" compared with fackets_out (see sacktag) */
+       if (tp->fastpath_skb_hint != NULL &&
+           after(TCP_SKB_CB(tp->fastpath_skb_hint)->seq, TCP_SKB_CB(skb)->seq))
+               tp->fastpath_cnt_hint -= decr;
+}
+
 /* Function to create two new TCP segments.  Shrinks the given segment
  * to the specified size and appends a new segment with the rest of the
- * packet to the list.  This won't be called frequently, I hope. 
+ * packet to the list.  This won't be called frequently, I hope.
  * Remember, these are still headerless SKBs at this point.
  */
-static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
+int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss_now)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *buff;
-       int nsize;
+       int nsize, old_factor;
+       int nlen;
        u16 flags;
 
+       BUG_ON(len > skb->len);
+
+       tcp_clear_retrans_hints_partial(tp);
        nsize = skb_headlen(skb) - len;
        if (nsize < 0)
                nsize = 0;
@@ -449,23 +701,29 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
        buff = sk_stream_alloc_skb(sk, nsize, GFP_ATOMIC);
        if (buff == NULL)
                return -ENOMEM; /* We'll just try again later. */
+
        sk_charge_skb(sk, buff);
+       nlen = skb->len - len - nsize;
+       buff->truesize += nlen;
+       skb->truesize -= nlen;
 
        /* Correct the sequence numbers. */
        TCP_SKB_CB(buff)->seq = TCP_SKB_CB(skb)->seq + len;
        TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq;
        TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq;
 
+       if (tcp_is_sack(tp) && tp->sacked_out &&
+           (TCP_SKB_CB(skb)->seq == tp->highest_sack))
+               tp->highest_sack = TCP_SKB_CB(buff)->seq;
+
        /* PSH and FIN should only be set in the second packet. */
        flags = TCP_SKB_CB(skb)->flags;
        TCP_SKB_CB(skb)->flags = flags & ~(TCPCB_FLAG_FIN|TCPCB_FLAG_PSH);
        TCP_SKB_CB(buff)->flags = flags;
-       TCP_SKB_CB(buff)->sacked =
-               (TCP_SKB_CB(skb)->sacked &
-                (TCPCB_LOST | TCPCB_EVER_RETRANS | TCPCB_AT_TAIL));
+       TCP_SKB_CB(buff)->sacked = TCP_SKB_CB(skb)->sacked;
        TCP_SKB_CB(skb)->sacked &= ~TCPCB_AT_TAIL;
 
-       if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_HW) {
+       if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_PARTIAL) {
                /* Copy and checksum data tail into the new buffer. */
                buff->csum = csum_partial_copy_nocheck(skb->data + len, skb_put(buff, nsize),
                                                       nsize, 0);
@@ -474,7 +732,7 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
 
                skb->csum = csum_block_sub(skb->csum, buff->csum, len);
        } else {
-               skb->ip_summed = CHECKSUM_HW;
+               skb->ip_summed = CHECKSUM_PARTIAL;
                skb_split(skb, buff, len);
        }
 
@@ -484,30 +742,42 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
         * skbs, which it never sent before. --ANK
         */
        TCP_SKB_CB(buff)->when = TCP_SKB_CB(skb)->when;
-       buff->stamp = skb->stamp;
+       buff->tstamp = skb->tstamp;
 
-       if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {
-               tp->lost_out -= tcp_skb_pcount(skb);
-               tp->left_out -= tcp_skb_pcount(skb);
-       }
+       old_factor = tcp_skb_pcount(skb);
 
        /* Fix up tso_factor for both original and new SKB.  */
-       tcp_set_skb_tso_segs(sk, skb);
-       tcp_set_skb_tso_segs(sk, buff);
+       tcp_set_skb_tso_segs(sk, skb, mss_now);
+       tcp_set_skb_tso_segs(sk, buff, mss_now);
 
-       if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {
-               tp->lost_out += tcp_skb_pcount(skb);
-               tp->left_out += tcp_skb_pcount(skb);
-       }
+       /* If this packet has been sent out already, we must
+        * adjust the various packet counters.
+        */
+       if (!before(tp->snd_nxt, TCP_SKB_CB(buff)->end_seq)) {
+               int diff = old_factor - tcp_skb_pcount(skb) -
+                       tcp_skb_pcount(buff);
+
+               tp->packets_out -= diff;
 
-       if (TCP_SKB_CB(buff)->sacked&TCPCB_LOST) {
-               tp->lost_out += tcp_skb_pcount(buff);
-               tp->left_out += tcp_skb_pcount(buff);
+               if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
+                       tp->sacked_out -= diff;
+               if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)
+                       tp->retrans_out -= diff;
+
+               if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST)
+                       tp->lost_out -= diff;
+
+               /* Adjust Reno SACK estimate. */
+               if (tcp_is_reno(tp) && diff > 0) {
+                       tcp_dec_pcount_approx_int(&tp->sacked_out, diff);
+                       tcp_verify_left_out(tp);
+               }
+               tcp_adjust_fackets_out(tp, skb, diff);
        }
 
        /* Link BUFF into the send queue. */
        skb_header_release(buff);
-       __skb_append(skb, buff);
+       tcp_insert_write_queue_after(skb, buff, sk);
 
        return 0;
 }
@@ -516,7 +786,7 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
  * eventually). The difference is that pulled data not copied, but
  * immediately discarded.
  */
-static unsigned char *__pskb_trim_head(struct sk_buff *skb, int len)
+static void __pskb_trim_head(struct sk_buff *skb, int len)
 {
        int i, k, eat;
 
@@ -538,10 +808,9 @@ static unsigned char *__pskb_trim_head(struct sk_buff *skb, int len)
        }
        skb_shinfo(skb)->nr_frags = k;
 
-       skb->tail = skb->data;
+       skb_reset_tail_pointer(skb);
        skb->data_len -= len;
        skb->len = skb->data_len;
-       return skb->tail;
 }
 
 int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
@@ -550,15 +819,14 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
            pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
                return -ENOMEM;
 
-       if (len <= skb_headlen(skb)) {
+       /* If len == headlen, we avoid __skb_pull to preserve alignment. */
+       if (unlikely(len < skb_headlen(skb)))
                __skb_pull(skb, len);
-       } else {
-               if (__pskb_trim_head(skb, len-skb_headlen(skb)) == NULL)
-                       return -ENOMEM;
-       }
+       else
+               __pskb_trim_head(skb, len - skb_headlen(skb));
 
        TCP_SKB_CB(skb)->seq += len;
-       skb->ip_summed = CHECKSUM_HW;
+       skb->ip_summed = CHECKSUM_PARTIAL;
 
        skb->truesize        -= len;
        sk->sk_wmem_queued   -= len;
@@ -569,21 +837,77 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
         * factor and mss.
         */
        if (tcp_skb_pcount(skb) > 1)
-               tcp_set_skb_tso_segs(sk, skb);
+               tcp_set_skb_tso_segs(sk, skb, tcp_current_mss(sk, 1));
 
        return 0;
 }
 
+/* Not accounting for SACKs here. */
+int tcp_mtu_to_mss(struct sock *sk, int pmtu)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       int mss_now;
+
+       /* Calculate base mss without TCP options:
+          It is MMS_S - sizeof(tcphdr) of rfc1122
+        */
+       mss_now = pmtu - icsk->icsk_af_ops->net_header_len - sizeof(struct tcphdr);
+
+       /* Clamp it (mss_clamp does not include tcp options) */
+       if (mss_now > tp->rx_opt.mss_clamp)
+               mss_now = tp->rx_opt.mss_clamp;
+
+       /* Now subtract optional transport overhead */
+       mss_now -= icsk->icsk_ext_hdr_len;
+
+       /* Then reserve room for full set of TCP options and 8 bytes of data */
+       if (mss_now < 48)
+               mss_now = 48;
+
+       /* Now subtract TCP options size, not including SACKs */
+       mss_now -= tp->tcp_header_len - sizeof(struct tcphdr);
+
+       return mss_now;
+}
+
+/* Inverse of above */
+int tcp_mss_to_mtu(struct sock *sk, int mss)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       int mtu;
+
+       mtu = mss +
+             tp->tcp_header_len +
+             icsk->icsk_ext_hdr_len +
+             icsk->icsk_af_ops->net_header_len;
+
+       return mtu;
+}
+
+void tcp_mtup_init(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+
+       icsk->icsk_mtup.enabled = sysctl_tcp_mtu_probing > 1;
+       icsk->icsk_mtup.search_high = tp->rx_opt.mss_clamp + sizeof(struct tcphdr) +
+                              icsk->icsk_af_ops->net_header_len;
+       icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, sysctl_tcp_base_mss);
+       icsk->icsk_mtup.probe_size = 0;
+}
+
 /* This function synchronize snd mss to current pmtu/exthdr set.
 
    tp->rx_opt.user_mss is mss set by user by TCP_MAXSEG. It does NOT counts
    for TCP options, but includes only bare TCP header.
 
    tp->rx_opt.mss_clamp is mss negotiated at connection setup.
-   It is minumum of user_mss and mss received with SYN.
+   It is minimum of user_mss and mss received with SYN.
    It also does not include TCP options.
 
-   tp->pmtu_cookie is last pmtu, seen by this function.
+   inet_csk(sk)->icsk_pmtu_cookie is last pmtu, seen by this function.
 
    tp->mss_cache is current effective sending mss, including
    all tcp options except for SACKs. It is evaluated,
@@ -593,40 +917,29 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
    NOTE1. rfc1122 clearly states that advertised MSS
    DOES NOT include either tcp or ip options.
 
-   NOTE2. tp->pmtu_cookie and tp->mss_cache are READ ONLY outside
-   this function.                      --ANK (980731)
+   NOTE2. inet_csk(sk)->icsk_pmtu_cookie and tp->mss_cache
+   are READ ONLY outside this function.                --ANK (980731)
  */
 
 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu)
 {
        struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
        int mss_now;
 
-       /* Calculate base mss without TCP options:
-          It is MMS_S - sizeof(tcphdr) of rfc1122
-        */
-       mss_now = pmtu - tp->af_specific->net_header_len - sizeof(struct tcphdr);
-
-       /* Clamp it (mss_clamp does not include tcp options) */
-       if (mss_now > tp->rx_opt.mss_clamp)
-               mss_now = tp->rx_opt.mss_clamp;
-
-       /* Now subtract optional transport overhead */
-       mss_now -= tp->ext_header_len;
-
-       /* Then reserve room for full set of TCP options and 8 bytes of data */
-       if (mss_now < 48)
-               mss_now = 48;
+       if (icsk->icsk_mtup.search_high > pmtu)
+               icsk->icsk_mtup.search_high = pmtu;
 
-       /* Now subtract TCP options size, not including SACKs */
-       mss_now -= tp->tcp_header_len - sizeof(struct tcphdr);
+       mss_now = tcp_mtu_to_mss(sk, pmtu);
 
        /* Bound mss with half of window */
        if (tp->max_window && mss_now > (tp->max_window>>1))
                mss_now = max((tp->max_window>>1), 68U - tp->tcp_header_len);
 
        /* And store cached results */
-       tp->pmtu_cookie = pmtu;
+       icsk->icsk_pmtu_cookie = pmtu;
+       if (icsk->icsk_mtup.enabled)
+               mss_now = min(mss_now, tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low));
        tp->mss_cache = mss_now;
 
        return mss_now;
@@ -649,14 +962,12 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
 
        mss_now = tp->mss_cache;
 
-       if (large_allowed &&
-           (sk->sk_route_caps & NETIF_F_TSO) &&
-           !tp->urg_mode)
+       if (large_allowed && sk_can_gso(sk) && !tp->urg_mode)
                doing_tso = 1;
 
        if (dst) {
                u32 mtu = dst_mtu(dst);
-               if (mtu != tp->pmtu_cookie)
+               if (mtu != inet_csk(sk)->icsk_pmtu_cookie)
                        mss_now = tcp_sync_mss(sk, mtu);
        }
 
@@ -664,12 +975,18 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
                mss_now -= (TCPOLEN_SACK_BASE_ALIGNED +
                            (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK));
 
+#ifdef CONFIG_TCP_MD5SIG
+       if (tp->af_specific->md5_lookup(sk, sk))
+               mss_now -= TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
        xmit_size_goal = mss_now;
 
        if (doing_tso) {
-               xmit_size_goal = 65535 -
-                       tp->af_specific->net_header_len -
-                       tp->ext_header_len - tp->tcp_header_len;
+               xmit_size_goal = (65535 -
+                                 inet_csk(sk)->icsk_af_ops->net_header_len -
+                                 inet_csk(sk)->icsk_ext_hdr_len -
+                                 tp->tcp_header_len);
 
                if (tp->max_window &&
                    (xmit_size_goal > (tp->max_window >> 1)))
@@ -685,8 +1002,9 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
 
 /* Congestion window validation. (RFC2861) */
 
-static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
+static void tcp_cwnd_validate(struct sock *sk)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
        __u32 packets_out = tp->packets_out;
 
        if (packets_out >= tp->snd_cwnd) {
@@ -698,7 +1016,8 @@ static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
                if (tp->packets_out > tp->snd_cwnd_used)
                        tp->snd_cwnd_used = tp->packets_out;
 
-               if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto)
+               if (sysctl_tcp_slow_start_after_idle &&
+                   (s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= inet_csk(sk)->icsk_rto)
                        tcp_cwnd_application_limited(sk);
        }
 }
@@ -720,7 +1039,8 @@ static inline unsigned int tcp_cwnd_test(struct tcp_sock *tp, struct sk_buff *sk
        u32 in_flight, cwnd;
 
        /* Don't be strict about the congestion window for the final FIN.  */
-       if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)
+       if ((TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
+           tcp_skb_pcount(skb) == 1)
                return 1;
 
        in_flight = tcp_packets_in_flight(tp);
@@ -734,12 +1054,14 @@ static inline unsigned int tcp_cwnd_test(struct tcp_sock *tp, struct sk_buff *sk
 /* This must be invoked the first time we consider transmitting
  * SKB onto the wire.
  */
-static inline int tcp_init_tso_segs(struct sock *sk, struct sk_buff *skb)
+static int tcp_init_tso_segs(struct sock *sk, struct sk_buff *skb, unsigned int mss_now)
 {
        int tso_segs = tcp_skb_pcount(skb);
 
-       if (!tso_segs) {
-               tcp_set_skb_tso_segs(sk, skb);
+       if (!tso_segs ||
+           (tso_segs > 1 &&
+            tcp_skb_mss(skb) != mss_now)) {
+               tcp_set_skb_tso_segs(sk, skb, mss_now);
                tso_segs = tcp_skb_pcount(skb);
        }
        return tso_segs;
@@ -760,7 +1082,7 @@ static inline int tcp_minshall_check(const struct tcp_sock *tp)
  */
 
 static inline int tcp_nagle_check(const struct tcp_sock *tp,
-                                 const struct sk_buff *skb, 
+                                 const struct sk_buff *skb,
                                  unsigned mss_now, int nonagle)
 {
        return (skb->len < mss_now &&
@@ -785,8 +1107,10 @@ static inline int tcp_nagle_test(struct tcp_sock *tp, struct sk_buff *skb,
        if (nonagle & TCP_NAGLE_PUSH)
                return 1;
 
-       /* Don't use the nagle rule for urgent data (or for the final FIN).  */
-       if (tp->urg_mode ||
+       /* Don't use the nagle rule for urgent data (or for the final FIN).
+        * Nagle can be ignored during F-RTO too (see RFC4138).
+        */
+       if (tp->urg_mode || (tp->frto_counter == 2) ||
            (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN))
                return 1;
 
@@ -807,7 +1131,7 @@ static inline int tcp_snd_wnd_test(struct tcp_sock *tp, struct sk_buff *skb, uns
        return !after(end_seq, tp->snd_una + tp->snd_wnd);
 }
 
-/* This checks if the data bearing packet SKB (usually sk->sk_send_head)
+/* This checks if the data bearing packet SKB (usually tcp_send_head(sk))
  * should be put on the wire right now.  If so, it returns the number of
  * packets allowed by the congestion window.
  */
@@ -817,7 +1141,7 @@ static unsigned int tcp_snd_test(struct sock *sk, struct sk_buff *skb,
        struct tcp_sock *tp = tcp_sk(sk);
        unsigned int cwnd_quota;
 
-       tcp_init_tso_segs(sk, skb);
+       tcp_init_tso_segs(sk, skb, cur_mss);
 
        if (!tcp_nagle_test(tp, skb, cur_mss, nonagle))
                return 0;
@@ -830,15 +1154,10 @@ static unsigned int tcp_snd_test(struct sock *sk, struct sk_buff *skb,
        return cwnd_quota;
 }
 
-static inline int tcp_skb_is_last(const struct sock *sk, 
-                                 const struct sk_buff *skb)
-{
-       return skb->next == (struct sk_buff *)&sk->sk_write_queue;
-}
-
-int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp)
+int tcp_may_send_now(struct sock *sk)
 {
-       struct sk_buff *skb = sk->sk_send_head;
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sk_buff *skb = tcp_send_head(sk);
 
        return (skb &&
                tcp_snd_test(sk, skb, tcp_current_mss(sk, 1),
@@ -854,20 +1173,22 @@ int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp)
  * know that all the data is in scatter-gather pages, and that the
  * packet has never been sent out before (and thus is not cloned).
  */
-static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len)
+static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len, unsigned int mss_now)
 {
        struct sk_buff *buff;
        int nlen = skb->len - len;
        u16 flags;
 
        /* All of a TSO frame must be composed of paged data.  */
-       BUG_ON(skb->len != skb->data_len);
+       if (skb->len != skb->data_len)
+               return tcp_fragment(sk, skb, len, mss_now);
 
        buff = sk_stream_alloc_pskb(sk, 0, 0, GFP_ATOMIC);
        if (unlikely(buff == NULL))
                return -ENOMEM;
 
-       buff->truesize = nlen;
+       sk_charge_skb(sk, buff);
+       buff->truesize += nlen;
        skb->truesize -= nlen;
 
        /* Correct the sequence numbers. */
@@ -883,16 +1204,16 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len)
        /* This packet was never sent out yet, so no SACK bits. */
        TCP_SKB_CB(buff)->sacked = 0;
 
-       buff->ip_summed = skb->ip_summed = CHECKSUM_HW;
+       buff->ip_summed = skb->ip_summed = CHECKSUM_PARTIAL;
        skb_split(skb, buff, len);
 
        /* Fix up tso_factor for both original and new SKB.  */
-       tcp_set_skb_tso_segs(sk, skb);
-       tcp_set_skb_tso_segs(sk, buff);
+       tcp_set_skb_tso_segs(sk, skb, mss_now);
+       tcp_set_skb_tso_segs(sk, buff, mss_now);
 
        /* Link BUFF into the send queue. */
        skb_header_release(buff);
-       __skb_append(skb, buff);
+       tcp_insert_write_queue_after(skb, buff, sk);
 
        return 0;
 }
@@ -902,12 +1223,21 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len)
  *
  * This algorithm is from John Heffner.
  */
-static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_buff *skb)
+static int tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        u32 send_win, cong_win, limit, in_flight;
 
        if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)
-               return 0;
+               goto send_now;
+
+       if (icsk->icsk_ca_state != TCP_CA_Open)
+               goto send_now;
+
+       /* Defer for less than two clock ticks. */
+       if (!tp->tso_deferred && ((jiffies<<1)>>1) - (tp->tso_deferred>>1) > 1)
+               goto send_now;
 
        in_flight = tcp_packets_in_flight(tp);
 
@@ -921,9 +1251,9 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
 
        limit = min(send_win, cong_win);
 
-       /* If sk_send_head can be sent fully now, just do it.  */
-       if (skb->len <= limit)
-               return 0;
+       /* If a full-sized TSO skb can be sent, do it. */
+       if (limit >= 65536)
+               goto send_now;
 
        if (sysctl_tcp_tso_win_divisor) {
                u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache);
@@ -933,7 +1263,7 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
                 */
                chunk /= sysctl_tcp_tso_win_divisor;
                if (limit >= chunk)
-                       return 0;
+                       goto send_now;
        } else {
                /* Different approach, try not to defer past a single
                 * ACK.  Receiver should ACK every other full sized
@@ -941,13 +1271,152 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
                 * then send now.
                 */
                if (limit > tcp_max_burst(tp) * tp->mss_cache)
-                       return 0;
+                       goto send_now;
        }
 
        /* Ok, it looks like it is advisable to defer.  */
+       tp->tso_deferred = 1 | (jiffies<<1);
+
        return 1;
+
+send_now:
+       tp->tso_deferred = 0;
+       return 0;
 }
 
+/* Create a new MTU probe if we are ready.
+ * Returns 0 if we should wait to probe (no cwnd available),
+ *         1 if a probe was sent,
+ *         -1 otherwise */
+static int tcp_mtu_probe(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       struct sk_buff *skb, *nskb, *next;
+       int len;
+       int probe_size;
+       unsigned int pif;
+       int copy;
+       int mss_now;
+
+       /* Not currently probing/verifying,
+        * not in recovery,
+        * have enough cwnd, and
+        * not SACKing (the variable headers throw things off) */
+       if (!icsk->icsk_mtup.enabled ||
+           icsk->icsk_mtup.probe_size ||
+           inet_csk(sk)->icsk_ca_state != TCP_CA_Open ||
+           tp->snd_cwnd < 11 ||
+           tp->rx_opt.eff_sacks)
+               return -1;
+
+       /* Very simple search strategy: just double the MSS. */
+       mss_now = tcp_current_mss(sk, 0);
+       probe_size = 2*tp->mss_cache;
+       if (probe_size > tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_high)) {
+               /* TODO: set timer for probe_converge_event */
+               return -1;
+       }
+
+       /* Have enough data in the send queue to probe? */
+       len = 0;
+       if ((skb = tcp_send_head(sk)) == NULL)
+               return -1;
+       while ((len += skb->len) < probe_size && !tcp_skb_is_last(sk, skb))
+               skb = tcp_write_queue_next(sk, skb);
+       if (len < probe_size)
+               return -1;
+
+       /* Receive window check. */
+       if (after(TCP_SKB_CB(skb)->seq + probe_size, tp->snd_una + tp->snd_wnd)) {
+               if (tp->snd_wnd < probe_size)
+                       return -1;
+               else
+                       return 0;
+       }
+
+       /* Do we need to wait to drain cwnd? */
+       pif = tcp_packets_in_flight(tp);
+       if (pif + 2 > tp->snd_cwnd) {
+               /* With no packets in flight, don't stall. */
+               if (pif == 0)
+                       return -1;
+               else
+                       return 0;
+       }
+
+       /* We're allowed to probe.  Build it now. */
+       if ((nskb = sk_stream_alloc_skb(sk, probe_size, GFP_ATOMIC)) == NULL)
+               return -1;
+       sk_charge_skb(sk, nskb);
+
+       skb = tcp_send_head(sk);
+       tcp_insert_write_queue_before(nskb, skb, sk);
+       tcp_advance_send_head(sk, skb);
+
+       TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(skb)->seq;
+       TCP_SKB_CB(nskb)->end_seq = TCP_SKB_CB(skb)->seq + probe_size;
+       TCP_SKB_CB(nskb)->flags = TCPCB_FLAG_ACK;
+       TCP_SKB_CB(nskb)->sacked = 0;
+       nskb->csum = 0;
+       nskb->ip_summed = skb->ip_summed;
+
+       len = 0;
+       while (len < probe_size) {
+               next = tcp_write_queue_next(sk, skb);
+
+               copy = min_t(int, skb->len, probe_size - len);
+               if (nskb->ip_summed)
+                       skb_copy_bits(skb, 0, skb_put(nskb, copy), copy);
+               else
+                       nskb->csum = skb_copy_and_csum_bits(skb, 0,
+                                        skb_put(nskb, copy), copy, nskb->csum);
+
+               if (skb->len <= copy) {
+                       /* We've eaten all the data from this skb.
+                        * Throw it away. */
+                       TCP_SKB_CB(nskb)->flags |= TCP_SKB_CB(skb)->flags;
+                       tcp_unlink_write_queue(skb, sk);
+                       sk_stream_free_skb(sk, skb);
+               } else {
+                       TCP_SKB_CB(nskb)->flags |= TCP_SKB_CB(skb)->flags &
+                                                  ~(TCPCB_FLAG_FIN|TCPCB_FLAG_PSH);
+                       if (!skb_shinfo(skb)->nr_frags) {
+                               skb_pull(skb, copy);
+                               if (skb->ip_summed != CHECKSUM_PARTIAL)
+                                       skb->csum = csum_partial(skb->data, skb->len, 0);
+                       } else {
+                               __pskb_trim_head(skb, copy);
+                               tcp_set_skb_tso_segs(sk, skb, mss_now);
+                       }
+                       TCP_SKB_CB(skb)->seq += copy;
+               }
+
+               len += copy;
+               skb = next;
+       }
+       tcp_init_tso_segs(sk, nskb, nskb->len);
+
+       /* We're ready to send.  If this fails, the probe will
+        * be resegmented into mss-sized pieces by tcp_write_xmit(). */
+       TCP_SKB_CB(nskb)->when = tcp_time_stamp;
+       if (!tcp_transmit_skb(sk, nskb, 1, GFP_ATOMIC)) {
+               /* Decrement cwnd here because we are sending
+               * effectively two packets. */
+               tp->snd_cwnd--;
+               update_send_head(sk, nskb);
+
+               icsk->icsk_mtup.probe_size = tcp_mss_to_mtu(sk, nskb->len);
+               tp->mtu_probe.probe_seq_start = TCP_SKB_CB(nskb)->seq;
+               tp->mtu_probe.probe_seq_end = TCP_SKB_CB(nskb)->end_seq;
+
+               return 1;
+       }
+
+       return -1;
+}
+
+
 /* This routine writes packets to the network.  It advances the
  * send_head.  This happens as incoming acks open up the remote
  * window for us.
@@ -961,6 +1430,7 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle)
        struct sk_buff *skb;
        unsigned int tso_segs, sent_pkts;
        int cwnd_quota;
+       int result;
 
        /* If we are closed, the bytes will have to remain here.
         * In time closedown will finish, we empty the write queue and all
@@ -969,32 +1439,42 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle)
        if (unlikely(sk->sk_state == TCP_CLOSE))
                return 0;
 
-       skb = sk->sk_send_head;
-       if (unlikely(!skb))
+       sent_pkts = 0;
+
+       /* Do MTU probing. */
+       if ((result = tcp_mtu_probe(sk)) == 0) {
                return 0;
+       } else if (result > 0) {
+               sent_pkts = 1;
+       }
 
-       tso_segs = tcp_init_tso_segs(sk, skb);
-       cwnd_quota = tcp_cwnd_test(tp, skb);
-       if (unlikely(!cwnd_quota))
-               goto out;
+       while ((skb = tcp_send_head(sk))) {
+               unsigned int limit;
 
-       sent_pkts = 0;
-       while (likely(tcp_snd_wnd_test(tp, skb, mss_now))) {
+               tso_segs = tcp_init_tso_segs(sk, skb, mss_now);
                BUG_ON(!tso_segs);
 
+               cwnd_quota = tcp_cwnd_test(tp, skb);
+               if (!cwnd_quota)
+                       break;
+
+               if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now)))
+                       break;
+
                if (tso_segs == 1) {
                        if (unlikely(!tcp_nagle_test(tp, skb, mss_now,
                                                     (tcp_skb_is_last(sk, skb) ?
                                                      nonagle : TCP_NAGLE_PUSH))))
                                break;
                } else {
-                       if (tcp_tso_should_defer(sk, tp, skb))
+                       if (tcp_tso_should_defer(sk, skb))
                                break;
                }
 
+               limit = mss_now;
                if (tso_segs > 1) {
-                       u32 limit = tcp_window_allows(tp, skb,
-                                                     mss_now, cwnd_quota);
+                       limit = tcp_window_allows(tp, skb,
+                                                 mss_now, cwnd_quota);
 
                        if (skb->len < limit) {
                                unsigned int trim = skb->len % mss_now;
@@ -1002,63 +1482,45 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle)
                                if (trim)
                                        limit = skb->len - trim;
                        }
-                       if (skb->len > limit) {
-                               if (tso_fragment(sk, skb, limit))
-                                       break;
-                       }
-               } else if (unlikely(skb->len > mss_now)) {
-                       if (unlikely(tcp_fragment(sk, skb,  mss_now)))
-                               break;
                }
 
+               if (skb->len > limit &&
+                   unlikely(tso_fragment(sk, skb, limit, mss_now)))
+                       break;
+
                TCP_SKB_CB(skb)->when = tcp_time_stamp;
 
-               if (unlikely(tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC))))
+               if (unlikely(tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC)))
                        break;
 
                /* Advance the send_head.  This one is sent out.
                 * This call will increment packets_out.
                 */
-               update_send_head(sk, tp, skb);
+               update_send_head(sk, skb);
 
                tcp_minshall_update(tp, mss_now, skb);
                sent_pkts++;
-
-               /* Do not optimize this to use tso_segs. If we chopped up
-                * the packet above, tso_segs will no longer be valid.
-                */
-               cwnd_quota -= tcp_skb_pcount(skb);
-
-               BUG_ON(cwnd_quota < 0);
-               if (!cwnd_quota)
-                       break;
-
-               skb = sk->sk_send_head;
-               if (!skb)
-                       break;
-               tso_segs = tcp_init_tso_segs(sk, skb);
        }
 
        if (likely(sent_pkts)) {
-               tcp_cwnd_validate(sk, tp);
+               tcp_cwnd_validate(sk);
                return 0;
        }
-out:
-       return !tp->packets_out && sk->sk_send_head;
+       return !tp->packets_out && tcp_send_head(sk);
 }
 
 /* Push out any pending frames which were held back due to
  * TCP_CORK or attempt at coalescing tiny packets.
  * The socket must be locked by the caller.
  */
-void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
-                              unsigned int cur_mss, int nonagle)
+void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
+                              int nonagle)
 {
-       struct sk_buff *skb = sk->sk_send_head;
+       struct sk_buff *skb = tcp_send_head(sk);
 
        if (skb) {
                if (tcp_write_xmit(sk, cur_mss, nonagle))
-                       tcp_check_probe_timer(sk, tp);
+                       tcp_check_probe_timer(sk);
        }
 }
 
@@ -1068,20 +1530,23 @@ void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
 void tcp_push_one(struct sock *sk, unsigned int mss_now)
 {
        struct tcp_sock *tp = tcp_sk(sk);
-       struct sk_buff *skb = sk->sk_send_head;
+       struct sk_buff *skb = tcp_send_head(sk);
        unsigned int tso_segs, cwnd_quota;
 
        BUG_ON(!skb || skb->len < mss_now);
 
-       tso_segs = tcp_init_tso_segs(sk, skb);
+       tso_segs = tcp_init_tso_segs(sk, skb, mss_now);
        cwnd_quota = tcp_snd_test(sk, skb, mss_now, TCP_NAGLE_PUSH);
 
        if (likely(cwnd_quota)) {
+               unsigned int limit;
+
                BUG_ON(!tso_segs);
 
+               limit = mss_now;
                if (tso_segs > 1) {
-                       u32 limit = tcp_window_allows(tp, skb,
-                                                     mss_now, cwnd_quota);
+                       limit = tcp_window_allows(tp, skb,
+                                                 mss_now, cwnd_quota);
 
                        if (skb->len < limit) {
                                unsigned int trim = skb->len % mss_now;
@@ -1089,21 +1554,18 @@ void tcp_push_one(struct sock *sk, unsigned int mss_now)
                                if (trim)
                                        limit = skb->len - trim;
                        }
-                       if (skb->len > limit) {
-                               if (unlikely(tso_fragment(sk, skb, limit)))
-                                       return;
-                       }
-               } else if (unlikely(skb->len > mss_now)) {
-                       if (unlikely(tcp_fragment(sk, skb, mss_now)))
-                               return;
                }
 
+               if (skb->len > limit &&
+                   unlikely(tso_fragment(sk, skb, limit, mss_now)))
+                       return;
+
                /* Send it out now. */
                TCP_SKB_CB(skb)->when = tcp_time_stamp;
 
-               if (likely(!tcp_transmit_skb(sk, skb_clone(skb, sk->sk_allocation)))) {
-                       update_send_head(sk, tp, skb);
-                       tcp_cwnd_validate(sk, tp);
+               if (likely(!tcp_transmit_skb(sk, skb, 1, sk->sk_allocation))) {
+                       update_send_head(sk, skb);
+                       tcp_cwnd_validate(sk);
                        return;
                }
        }
@@ -1111,7 +1573,7 @@ void tcp_push_one(struct sock *sk, unsigned int mss_now)
 
 /* This function returns the amount that we can raise the
  * usable window based on the following constraints
- *  
+ *
  * 1. The window can never be shrunk once it is offered (RFC 793)
  * 2. We limit memory per socket
  *
@@ -1130,12 +1592,12 @@ void tcp_push_one(struct sock *sk, unsigned int mss_now)
  * side SWS prevention criteria. The problem is that under this rule
  * a stream of single byte packets will cause the right side of the
  * window to always advance by a single byte.
- * 
+ *
  * Of course, if the sender implements sender side SWS prevention
  * then this will not be a problem.
- * 
+ *
  * BSD seems to make the following compromise:
- * 
+ *
  *     If the free space is less than the 1/4 of the maximum
  *     space available and the free space is less than 1/2 mss,
  *     then set the window to 0.
@@ -1163,23 +1625,24 @@ void tcp_push_one(struct sock *sk, unsigned int mss_now)
  */
 u32 __tcp_select_window(struct sock *sk)
 {
+       struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
-       /* MSS for the peer's data.  Previous verions used mss_clamp
+       /* MSS for the peer's data.  Previous versions used mss_clamp
         * here.  I don't know if the value based on our guesses
         * of peer's MSS is better for the performance.  It's more correct
         * but may be worse for the performance because of rcv_mss
         * fluctuations.  --SAW  1998/11/1
         */
-       int mss = tp->ack.rcv_mss;
+       int mss = icsk->icsk_ack.rcv_mss;
        int free_space = tcp_space(sk);
        int full_space = min_t(int, tp->window_clamp, tcp_full_space(sk));
        int window;
 
        if (mss > full_space)
-               mss = full_space; 
+               mss = full_space;
 
        if (free_space < full_space/2) {
-               tp->ack.quick = 0;
+               icsk->icsk_ack.quick = 0;
 
                if (tcp_memory_pressure)
                        tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U*tp->advmss);
@@ -1216,6 +1679,9 @@ u32 __tcp_select_window(struct sock *sk)
                 */
                if (window <= free_space - mss || window > free_space)
                        window = (free_space/mss)*mss;
+               else if (mss == full_space &&
+                        free_space > window + full_space/2)
+                       window = free_space;
        }
 
        return window;
@@ -1225,7 +1691,7 @@ u32 __tcp_select_window(struct sock *sk)
 static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int mss_now)
 {
        struct tcp_sock *tp = tcp_sk(sk);
-       struct sk_buff *next_skb = skb->next;
+       struct sk_buff *next_skb = tcp_write_queue_next(sk, skb);
 
        /* The first test we must make is that neither of these two
         * SKB's are still referenced by someone else.
@@ -1235,7 +1701,7 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
                u16 flags = TCP_SKB_CB(skb)->flags;
 
                /* Also punt if next skb has been SACK'd. */
-               if(TCP_SKB_CB(next_skb)->sacked & TCPCB_SACKED_ACKED)
+               if (TCP_SKB_CB(next_skb)->sacked & TCPCB_SACKED_ACKED)
                        return;
 
                /* Next skb is out of window. */
@@ -1253,15 +1719,21 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
                BUG_ON(tcp_skb_pcount(skb) != 1 ||
                       tcp_skb_pcount(next_skb) != 1);
 
-               /* Ok.  We will be able to collapse the packet. */
-               __skb_unlink(next_skb, next_skb->list);
+               if (WARN_ON(tcp_is_sack(tp) && tp->sacked_out &&
+                   (TCP_SKB_CB(next_skb)->seq == tp->highest_sack)))
+                       return;
+
+               /* Ok.  We will be able to collapse the packet. */
+               tcp_unlink_write_queue(next_skb, sk);
 
-               memcpy(skb_put(skb, next_skb_size), next_skb->data, next_skb_size);
+               skb_copy_from_linear_data(next_skb,
+                                         skb_put(skb, next_skb_size),
+                                         next_skb_size);
 
-               if (next_skb->ip_summed == CHECKSUM_HW)
-                       skb->ip_summed = CHECKSUM_HW;
+               if (next_skb->ip_summed == CHECKSUM_PARTIAL)
+                       skb->ip_summed = CHECKSUM_PARTIAL;
 
-               if (skb->ip_summed != CHECKSUM_HW)
+               if (skb->ip_summed != CHECKSUM_PARTIAL)
                        skb->csum = csum_block_add(skb->csum, next_skb->csum, skb_size);
 
                /* Update sequence range on original skb. */
@@ -1277,38 +1749,43 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
                TCP_SKB_CB(skb)->sacked |= TCP_SKB_CB(next_skb)->sacked&(TCPCB_EVER_RETRANS|TCPCB_AT_TAIL);
                if (TCP_SKB_CB(next_skb)->sacked&TCPCB_SACKED_RETRANS)
                        tp->retrans_out -= tcp_skb_pcount(next_skb);
-               if (TCP_SKB_CB(next_skb)->sacked&TCPCB_LOST) {
+               if (TCP_SKB_CB(next_skb)->sacked&TCPCB_LOST)
                        tp->lost_out -= tcp_skb_pcount(next_skb);
-                       tp->left_out -= tcp_skb_pcount(next_skb);
-               }
                /* Reno case is special. Sigh... */
-               if (!tp->rx_opt.sack_ok && tp->sacked_out) {
+               if (tcp_is_reno(tp) && tp->sacked_out)
                        tcp_dec_pcount_approx(&tp->sacked_out, next_skb);
-                       tp->left_out -= tcp_skb_pcount(next_skb);
+
+               tcp_adjust_fackets_out(tp, next_skb, tcp_skb_pcount(next_skb));
+               tp->packets_out -= tcp_skb_pcount(next_skb);
+
+               /* changed transmit queue under us so clear hints */
+               tcp_clear_retrans_hints_partial(tp);
+               /* manually tune sacktag skb hint */
+               if (tp->fastpath_skb_hint == next_skb) {
+                       tp->fastpath_skb_hint = skb;
+                       tp->fastpath_cnt_hint -= tcp_skb_pcount(skb);
                }
 
-               /* Not quite right: it can be > snd.fack, but
-                * it is better to underestimate fackets.
-                */
-               tcp_dec_pcount_approx(&tp->fackets_out, next_skb);
-               tcp_packets_out_dec(tp, next_skb);
                sk_stream_free_skb(sk, next_skb);
        }
 }
 
 /* Do a simple retransmit without using the backoff mechanisms in
- * tcp_timer. This is used for path mtu discovery. 
+ * tcp_timer. This is used for path mtu discovery.
  * The socket is already locked here.
- */ 
+ */
 void tcp_simple_retransmit(struct sock *sk)
 {
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
        unsigned int mss = tcp_current_mss(sk, 0);
        int lost = 0;
 
-       sk_stream_for_retrans_queue(skb, sk) {
-               if (skb->len > mss && 
+       tcp_for_write_queue(skb, sk) {
+               if (skb == tcp_send_head(sk))
+                       break;
+               if (skb->len > mss &&
                    !(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED)) {
                        if (TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_RETRANS) {
                                TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
@@ -1322,22 +1799,24 @@ void tcp_simple_retransmit(struct sock *sk)
                }
        }
 
+       tcp_clear_all_retrans_hints(tp);
+
        if (!lost)
                return;
 
-       tcp_sync_left_out(tp);
+       tcp_verify_left_out(tp);
 
-       /* Don't muck with the congestion window here.
+       /* Don't muck with the congestion window here.
         * Reason is that we do not increase amount of _data_
         * in network, but units changed and effective
         * cwnd/ssthresh really reduced now.
         */
-       if (tp->ca_state != TCP_CA_Loss) {
+       if (icsk->icsk_ca_state != TCP_CA_Loss) {
                tp->high_seq = tp->snd_nxt;
-               tp->snd_ssthresh = tcp_current_ssthresh(tp);
+               tp->snd_ssthresh = tcp_current_ssthresh(sk);
                tp->prior_ssthresh = 0;
                tp->undo_marker = 0;
-               tcp_set_ca_state(tp, TCP_CA_Loss);
+               tcp_set_ca_state(sk, TCP_CA_Loss);
        }
        tcp_xmit_retransmit_queue(sk);
 }
@@ -1349,11 +1828,17 @@ void tcp_simple_retransmit(struct sock *sk)
 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
-       unsigned int cur_mss = tcp_current_mss(sk, 0);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       unsigned int cur_mss = tcp_current_mss(sk, 0);
        int err;
 
+       /* Inconslusive MTU probe */
+       if (icsk->icsk_mtup.probe_size) {
+               icsk->icsk_mtup.probe_size = 0;
+       }
+
        /* Do not sent more than we queued. 1/4 is reserved for possible
-        * copying overhead: frgagmentation, tunneling, mangling etc.
+        * copying overhead: fragmentation, tunneling, mangling etc.
         */
        if (atomic_read(&sk->sk_wmem_alloc) >
            min(sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf))
@@ -1362,12 +1847,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
        if (before(TCP_SKB_CB(skb)->seq, tp->snd_una)) {
                if (before(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
                        BUG();
-
-               if (sk->sk_route_caps & NETIF_F_TSO) {
-                       sk->sk_route_caps &= ~NETIF_F_TSO;
-                       sock_set_flag(sk, SOCK_NO_LARGESEND);
-               }
-
                if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq))
                        return -ENOMEM;
        }
@@ -1382,42 +1861,35 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
                return -EAGAIN;
 
        if (skb->len > cur_mss) {
-               int old_factor = tcp_skb_pcount(skb);
-               int new_factor;
-
-               if (tcp_fragment(sk, skb, cur_mss))
+               if (tcp_fragment(sk, skb, cur_mss, cur_mss))
                        return -ENOMEM; /* We'll try again later. */
-
-               /* New SKB created, account for it. */
-               new_factor = tcp_skb_pcount(skb);
-               tp->packets_out -= old_factor - new_factor;
-               tp->packets_out += tcp_skb_pcount(skb->next);
        }
 
        /* Collapse two adjacent packets if worthwhile and we can. */
-       if(!(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_SYN) &&
-          (skb->len < (cur_mss >> 1)) &&
-          (skb->next != sk->sk_send_head) &&
-          (skb->next != (struct sk_buff *)&sk->sk_write_queue) &&
-          (skb_shinfo(skb)->nr_frags == 0 && skb_shinfo(skb->next)->nr_frags == 0) &&
-          (tcp_skb_pcount(skb) == 1 && tcp_skb_pcount(skb->next) == 1) &&
-          (sysctl_tcp_retrans_collapse != 0))
+       if (!(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_SYN) &&
+           (skb->len < (cur_mss >> 1)) &&
+           (tcp_write_queue_next(sk, skb) != tcp_send_head(sk)) &&
+           (!tcp_skb_is_last(sk, skb)) &&
+           (skb_shinfo(skb)->nr_frags == 0 && skb_shinfo(tcp_write_queue_next(sk, skb))->nr_frags == 0) &&
+           (tcp_skb_pcount(skb) == 1 && tcp_skb_pcount(tcp_write_queue_next(sk, skb)) == 1) &&
+           (sysctl_tcp_retrans_collapse != 0))
                tcp_retrans_try_collapse(sk, skb, cur_mss);
 
-       if(tp->af_specific->rebuild_header(sk))
+       if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk))
                return -EHOSTUNREACH; /* Routing failure or similar. */
 
        /* Some Solaris stacks overoptimize and ignore the FIN on a
         * retransmit when old data is attached.  So strip it off
         * since it is cheap to do so and saves bytes on the network.
         */
-       if(skb->len > 0 &&
-          (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
-          tp->snd_una == (TCP_SKB_CB(skb)->end_seq - 1)) {
+       if (skb->len > 0 &&
+           (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
+           tp->snd_una == (TCP_SKB_CB(skb)->end_seq - 1)) {
                if (!pskb_trim(skb, 0)) {
                        TCP_SKB_CB(skb)->seq = TCP_SKB_CB(skb)->end_seq - 1;
-                       skb_shinfo(skb)->tso_segs = 1;
-                       skb_shinfo(skb)->tso_size = 0;
+                       skb_shinfo(skb)->gso_segs = 1;
+                       skb_shinfo(skb)->gso_size = 0;
+                       skb_shinfo(skb)->gso_type = 0;
                        skb->ip_summed = CHECKSUM_NONE;
                        skb->csum = 0;
                }
@@ -1428,9 +1900,7 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
         */
        TCP_SKB_CB(skb)->when = tcp_time_stamp;
 
-       err = tcp_transmit_skb(sk, (skb_cloned(skb) ?
-                                   pskb_copy(skb, GFP_ATOMIC):
-                                   skb_clone(skb, GFP_ATOMIC)));
+       err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
 
        if (err == 0) {
                /* Update global TCP statistics. */
@@ -1444,6 +1914,8 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
                                printk(KERN_DEBUG "retrans_out leaked.\n");
                }
 #endif
+               if (!tp->retrans_out)
+                       tp->lost_retrans_low = tp->snd_nxt;
                TCP_SKB_CB(skb)->sacked |= TCPCB_RETRANS;
                tp->retrans_out += tcp_skb_pcount(skb);
 
@@ -1471,15 +1943,30 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
  */
 void tcp_xmit_retransmit_queue(struct sock *sk)
 {
+       const struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
-       int packet_cnt = tp->lost_out;
+       int packet_cnt;
+
+       if (tp->retransmit_skb_hint) {
+               skb = tp->retransmit_skb_hint;
+               packet_cnt = tp->retransmit_cnt_hint;
+       }else{
+               skb = tcp_write_queue_head(sk);
+               packet_cnt = 0;
+       }
 
        /* First pass: retransmit lost packets. */
-       if (packet_cnt) {
-               sk_stream_for_retrans_queue(skb, sk) {
+       if (tp->lost_out) {
+               tcp_for_write_queue_from(skb, sk) {
                        __u8 sacked = TCP_SKB_CB(skb)->sacked;
 
+                       if (skb == tcp_send_head(sk))
+                               break;
+                       /* we could do better than to assign each time */
+                       tp->retransmit_skb_hint = skb;
+                       tp->retransmit_cnt_hint = packet_cnt;
+
                        /* Assume this retransmit will generate
                         * only one packet for congestion window
                         * calculation purposes.  This works because
@@ -1490,22 +1977,25 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
                        if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
                                return;
 
-                       if (sacked&TCPCB_LOST) {
+                       if (sacked & TCPCB_LOST) {
                                if (!(sacked&(TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))) {
-                                       if (tcp_retransmit_skb(sk, skb))
+                                       if (tcp_retransmit_skb(sk, skb)) {
+                                               tp->retransmit_skb_hint = NULL;
                                                return;
-                                       if (tp->ca_state != TCP_CA_Loss)
+                                       }
+                                       if (icsk->icsk_ca_state != TCP_CA_Loss)
                                                NET_INC_STATS_BH(LINUX_MIB_TCPFASTRETRANS);
                                        else
                                                NET_INC_STATS_BH(LINUX_MIB_TCPSLOWSTARTRETRANS);
 
-                                       if (skb ==
-                                           skb_peek(&sk->sk_write_queue))
-                                               tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto);
+                                       if (skb == tcp_write_queue_head(sk))
+                                               inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+                                                                         inet_csk(sk)->icsk_rto,
+                                                                         TCP_RTO_MAX);
                                }
 
-                               packet_cnt -= tcp_skb_pcount(skb);
-                               if (packet_cnt <= 0)
+                               packet_cnt += tcp_skb_pcount(skb);
+                               if (packet_cnt >= tp->lost_out)
                                        break;
                        }
                }
@@ -1514,33 +2004,39 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
        /* OK, demanded retransmission is finished. */
 
        /* Forward retransmissions are possible only during Recovery. */
-       if (tp->ca_state != TCP_CA_Recovery)
+       if (icsk->icsk_ca_state != TCP_CA_Recovery)
                return;
 
        /* No forward retransmissions in Reno are possible. */
-       if (!tp->rx_opt.sack_ok)
+       if (tcp_is_reno(tp))
                return;
 
        /* Yeah, we have to make difficult choice between forward transmission
         * and retransmission... Both ways have their merits...
         *
         * For now we do not retransmit anything, while we have some new
-        * segments to send.
+        * segments to send. In the other cases, follow rule 3 for
+        * NextSeg() specified in RFC3517.
         */
 
-       if (tcp_may_send_now(sk, tp))
+       if (tcp_may_send_now(sk))
                return;
 
-       packet_cnt = 0;
+       /* If nothing is SACKed, highest_sack in the loop won't be valid */
+       if (!tp->sacked_out)
+               return;
 
-       sk_stream_for_retrans_queue(skb, sk) {
-               /* Similar to the retransmit loop above we
-                * can pretend that the retransmitted SKB
-                * we send out here will be composed of one
-                * real MSS sized packet because tcp_retransmit_skb()
-                * will fragment it if necessary.
-                */
-               if (++packet_cnt > tp->fackets_out)
+       if (tp->forward_skb_hint)
+               skb = tp->forward_skb_hint;
+       else
+               skb = tcp_write_queue_head(sk);
+
+       tcp_for_write_queue_from(skb, sk) {
+               if (skb == tcp_send_head(sk))
+                       break;
+               tp->forward_skb_hint = skb;
+
+               if (after(TCP_SKB_CB(skb)->seq, tp->highest_sack))
                        break;
 
                if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
@@ -1550,11 +2046,15 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
                        continue;
 
                /* Ok, retransmit it. */
-               if (tcp_retransmit_skb(sk, skb))
+               if (tcp_retransmit_skb(sk, skb)) {
+                       tp->forward_skb_hint = NULL;
                        break;
+               }
 
-               if (skb == skb_peek(&sk->sk_write_queue))
-                       tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto);
+               if (skb == tcp_write_queue_head(sk))
+                       inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+                                                 inet_csk(sk)->icsk_rto,
+                                                 TCP_RTO_MAX);
 
                NET_INC_STATS_BH(LINUX_MIB_TCPFORWARDRETRANS);
        }
@@ -1566,24 +2066,24 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
  */
 void tcp_send_fin(struct sock *sk)
 {
-       struct tcp_sock *tp = tcp_sk(sk);       
-       struct sk_buff *skb = skb_peek_tail(&sk->sk_write_queue);
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sk_buff *skb = tcp_write_queue_tail(sk);
        int mss_now;
-       
+
        /* Optimization, tack on the FIN if we have a queue of
         * unsent frames.  But be careful about outgoing SACKS
         * and IP options.
         */
        mss_now = tcp_current_mss(sk, 1);
 
-       if (sk->sk_send_head != NULL) {
+       if (tcp_send_head(sk) != NULL) {
                TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_FIN;
                TCP_SKB_CB(skb)->end_seq++;
                tp->write_seq++;
        } else {
                /* Socket is locked, keep trying until memory is available. */
                for (;;) {
-                       skb = alloc_skb(MAX_TCP_HEADER, GFP_KERNEL);
+                       skb = alloc_skb_fclone(MAX_TCP_HEADER, GFP_KERNEL);
                        if (skb)
                                break;
                        yield();
@@ -1594,25 +2094,25 @@ void tcp_send_fin(struct sock *sk)
                skb->csum = 0;
                TCP_SKB_CB(skb)->flags = (TCPCB_FLAG_ACK | TCPCB_FLAG_FIN);
                TCP_SKB_CB(skb)->sacked = 0;
-               skb_shinfo(skb)->tso_segs = 1;
-               skb_shinfo(skb)->tso_size = 0;
+               skb_shinfo(skb)->gso_segs = 1;
+               skb_shinfo(skb)->gso_size = 0;
+               skb_shinfo(skb)->gso_type = 0;
 
                /* FIN eats a sequence byte, write_seq advanced by tcp_queue_skb(). */
                TCP_SKB_CB(skb)->seq = tp->write_seq;
                TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + 1;
                tcp_queue_skb(sk, skb);
        }
-       __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_OFF);
+       __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_OFF);
 }
 
 /* We get here when a process closes a file descriptor (either due to
  * an explicit close() or as a byproduct of exit()'ing) and there
  * was unread data in the receive queue.  This behavior is recommended
- * by draft-ietf-tcpimpl-prob-03.txt section 3.10.  -DaveM
+ * by RFC 2525, section 2.17.  -DaveM
  */
-void tcp_send_active_reset(struct sock *sk, int priority)
+void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
 
        /* NOTE: No TCP options attached and we never retransmit this. */
@@ -1627,14 +2127,15 @@ void tcp_send_active_reset(struct sock *sk, int priority)
        skb->csum = 0;
        TCP_SKB_CB(skb)->flags = (TCPCB_FLAG_ACK | TCPCB_FLAG_RST);
        TCP_SKB_CB(skb)->sacked = 0;
-       skb_shinfo(skb)->tso_segs = 1;
-       skb_shinfo(skb)->tso_size = 0;
+       skb_shinfo(skb)->gso_segs = 1;
+       skb_shinfo(skb)->gso_size = 0;
+       skb_shinfo(skb)->gso_type = 0;
 
        /* Send it off. */
-       TCP_SKB_CB(skb)->seq = tcp_acceptable_seq(sk, tp);
+       TCP_SKB_CB(skb)->seq = tcp_acceptable_seq(sk);
        TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq;
        TCP_SKB_CB(skb)->when = tcp_time_stamp;
-       if (tcp_transmit_skb(sk, skb))
+       if (tcp_transmit_skb(sk, skb, 0, priority))
                NET_INC_STATS(LINUX_MIB_TCPABORTFAILED);
 }
 
@@ -1647,7 +2148,7 @@ int tcp_send_synack(struct sock *sk)
 {
        struct sk_buff* skb;
 
-       skb = skb_peek(&sk->sk_write_queue);
+       skb = tcp_write_queue_head(sk);
        if (skb == NULL || !(TCP_SKB_CB(skb)->flags&TCPCB_FLAG_SYN)) {
                printk(KERN_DEBUG "tcp_send_synack: wrong queue state\n");
                return -EFAULT;
@@ -1657,9 +2158,9 @@ int tcp_send_synack(struct sock *sk)
                        struct sk_buff *nskb = skb_copy(skb, GFP_ATOMIC);
                        if (nskb == NULL)
                                return -ENOMEM;
-                       __skb_unlink(skb, &sk->sk_write_queue);
+                       tcp_unlink_write_queue(skb, sk);
                        skb_header_release(nskb);
-                       __skb_queue_head(&sk->sk_write_queue, nskb);
+                       __tcp_add_write_queue_head(sk, nskb);
                        sk_stream_free_skb(sk, skb);
                        sk_charge_skb(sk, nskb);
                        skb = nskb;
@@ -1669,7 +2170,7 @@ int tcp_send_synack(struct sock *sk)
                TCP_ECN_send_synack(tcp_sk(sk), skb);
        }
        TCP_SKB_CB(skb)->when = tcp_time_stamp;
-       return tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC));
+       return tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
 }
 
 /*
@@ -1683,6 +2184,10 @@ struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
        struct tcphdr *th;
        int tcp_header_size;
        struct sk_buff *skb;
+#ifdef CONFIG_TCP_MD5SIG
+       struct tcp_md5sig_key *md5;
+       __u8 *md5_hash_location;
+#endif
 
        skb = sock_wmalloc(sk, MAX_TCP_HEADER + 15, 1, GFP_ATOMIC);
        if (skb == NULL)
@@ -1698,56 +2203,82 @@ struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
                           (ireq->wscale_ok ? TCPOLEN_WSCALE_ALIGNED : 0) +
                           /* SACK_PERM is in the place of NOP NOP of TS */
                           ((ireq->sack_ok && !ireq->tstamp_ok) ? TCPOLEN_SACKPERM_ALIGNED : 0));
-       skb->h.th = th = (struct tcphdr *) skb_push(skb, tcp_header_size);
 
+#ifdef CONFIG_TCP_MD5SIG
+       /* Are we doing MD5 on this segment? If so - make room for it */
+       md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req);
+       if (md5)
+               tcp_header_size += TCPOLEN_MD5SIG_ALIGNED;
+#endif
+       skb_push(skb, tcp_header_size);
+       skb_reset_transport_header(skb);
+
+       th = tcp_hdr(skb);
        memset(th, 0, sizeof(struct tcphdr));
        th->syn = 1;
        th->ack = 1;
-       if (dst->dev->features&NETIF_F_TSO)
-               ireq->ecn_ok = 0;
        TCP_ECN_make_synack(req, th);
        th->source = inet_sk(sk)->sport;
        th->dest = ireq->rmt_port;
        TCP_SKB_CB(skb)->seq = tcp_rsk(req)->snt_isn;
        TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + 1;
        TCP_SKB_CB(skb)->sacked = 0;
-       skb_shinfo(skb)->tso_segs = 1;
-       skb_shinfo(skb)->tso_size = 0;
+       skb_shinfo(skb)->gso_segs = 1;
+       skb_shinfo(skb)->gso_size = 0;
+       skb_shinfo(skb)->gso_type = 0;
        th->seq = htonl(TCP_SKB_CB(skb)->seq);
        th->ack_seq = htonl(tcp_rsk(req)->rcv_isn + 1);
        if (req->rcv_wnd == 0) { /* ignored for retransmitted syns */
-               __u8 rcv_wscale; 
+               __u8 rcv_wscale;
                /* Set this up on the first call only */
                req->window_clamp = tp->window_clamp ? : dst_metric(dst, RTAX_WINDOW);
                /* tcp_full_space because it is guaranteed to be the first packet */
-               tcp_select_initial_window(tcp_full_space(sk), 
+               tcp_select_initial_window(tcp_full_space(sk),
                        dst_metric(dst, RTAX_ADVMSS) - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0),
                        &req->rcv_wnd,
                        &req->window_clamp,
                        ireq->wscale_ok,
                        &rcv_wscale);
-               ireq->rcv_wscale = rcv_wscale; 
+               ireq->rcv_wscale = rcv_wscale;
        }
 
        /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */
-       th->window = htons(req->rcv_wnd);
+       th->window = htons(min(req->rcv_wnd, 65535U));
 
        TCP_SKB_CB(skb)->when = tcp_time_stamp;
-       tcp_syn_build_options((__u32 *)(th + 1), dst_metric(dst, RTAX_ADVMSS), ireq->tstamp_ok,
+       tcp_syn_build_options((__be32 *)(th + 1), dst_metric(dst, RTAX_ADVMSS), ireq->tstamp_ok,
                              ireq->sack_ok, ireq->wscale_ok, ireq->rcv_wscale,
                              TCP_SKB_CB(skb)->when,
-                             req->ts_recent);
+                             req->ts_recent,
+                             (
+#ifdef CONFIG_TCP_MD5SIG
+                              md5 ? &md5_hash_location :
+#endif
+                              NULL)
+                             );
 
        skb->csum = 0;
        th->doff = (tcp_header_size >> 2);
        TCP_INC_STATS(TCP_MIB_OUTSEGS);
+
+#ifdef CONFIG_TCP_MD5SIG
+       /* Okay, we have all we need - do the md5 hash if needed */
+       if (md5) {
+               tp->af_specific->calc_md5_hash(md5_hash_location,
+                                              md5,
+                                              NULL, dst, req,
+                                              tcp_hdr(skb), sk->sk_protocol,
+                                              skb->len);
+       }
+#endif
+
        return skb;
 }
 
-/* 
+/*
  * Do all connect socket setups that can be done AF independent.
- */ 
-static inline void tcp_connect_init(struct sock *sk)
+ */
+static void tcp_connect_init(struct sock *sk)
 {
        struct dst_entry *dst = __sk_dst_get(sk);
        struct tcp_sock *tp = tcp_sk(sk);
@@ -1759,10 +2290,16 @@ static inline void tcp_connect_init(struct sock *sk)
        tp->tcp_header_len = sizeof(struct tcphdr) +
                (sysctl_tcp_timestamps ? TCPOLEN_TSTAMP_ALIGNED : 0);
 
+#ifdef CONFIG_TCP_MD5SIG
+       if (tp->af_specific->md5_lookup(sk, sk) != NULL)
+               tp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
        /* If user gave his TCP_MAXSEG, record it to clamp */
        if (tp->rx_opt.user_mss)
                tp->rx_opt.mss_clamp = tp->rx_opt.user_mss;
        tp->max_window = 0;
+       tcp_mtup_init(sk);
        tcp_sync_mss(sk, dst_mtu(dst));
 
        if (!tp->window_clamp)
@@ -1790,14 +2327,14 @@ static inline void tcp_connect_init(struct sock *sk)
        tp->rcv_wup = 0;
        tp->copied_seq = 0;
 
-       tp->rto = TCP_TIMEOUT_INIT;
-       tp->retransmits = 0;
+       inet_csk(sk)->icsk_rto = TCP_TIMEOUT_INIT;
+       inet_csk(sk)->icsk_retransmits = 0;
        tcp_clear_retrans(tp);
 }
 
 /*
  * Build a SYN and send it off.
- */ 
+ */
 int tcp_connect(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
@@ -1805,7 +2342,7 @@ int tcp_connect(struct sock *sk)
 
        tcp_connect_init(sk);
 
-       buff = alloc_skb(MAX_TCP_HEADER + 15, sk->sk_allocation);
+       buff = alloc_skb_fclone(MAX_TCP_HEADER + 15, sk->sk_allocation);
        if (unlikely(buff == NULL))
                return -ENOBUFS;
 
@@ -1813,28 +2350,35 @@ int tcp_connect(struct sock *sk)
        skb_reserve(buff, MAX_TCP_HEADER);
 
        TCP_SKB_CB(buff)->flags = TCPCB_FLAG_SYN;
-       TCP_ECN_send_syn(sk, tp, buff);
+       TCP_ECN_send_syn(sk, buff);
        TCP_SKB_CB(buff)->sacked = 0;
-       skb_shinfo(buff)->tso_segs = 1;
-       skb_shinfo(buff)->tso_size = 0;
+       skb_shinfo(buff)->gso_segs = 1;
+       skb_shinfo(buff)->gso_size = 0;
+       skb_shinfo(buff)->gso_type = 0;
        buff->csum = 0;
+       tp->snd_nxt = tp->write_seq;
        TCP_SKB_CB(buff)->seq = tp->write_seq++;
        TCP_SKB_CB(buff)->end_seq = tp->write_seq;
-       tp->snd_nxt = tp->write_seq;
-       tp->pushed_seq = tp->write_seq;
 
        /* Send it off. */
        TCP_SKB_CB(buff)->when = tcp_time_stamp;
        tp->retrans_stamp = TCP_SKB_CB(buff)->when;
        skb_header_release(buff);
-       __skb_queue_tail(&sk->sk_write_queue, buff);
+       __tcp_add_write_queue_tail(sk, buff);
        sk_charge_skb(sk, buff);
        tp->packets_out += tcp_skb_pcount(buff);
-       tcp_transmit_skb(sk, skb_clone(buff, GFP_KERNEL));
+       tcp_transmit_skb(sk, buff, 1, GFP_KERNEL);
+
+       /* We change tp->snd_nxt after the tcp_transmit_skb() call
+        * in order to make this packet get counted in tcpOutSegs.
+        */
+       tp->snd_nxt = tp->write_seq;
+       tp->pushed_seq = tp->write_seq;
        TCP_INC_STATS(TCP_MIB_ACTIVEOPENS);
 
        /* Timer for repeating the SYN until an answer. */
-       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);
        return 0;
 }
 
@@ -1844,20 +2388,21 @@ int tcp_connect(struct sock *sk)
  */
 void tcp_send_delayed_ack(struct sock *sk)
 {
-       struct tcp_sock *tp = tcp_sk(sk);
-       int ato = tp->ack.ato;
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       int ato = icsk->icsk_ack.ato;
        unsigned long timeout;
 
        if (ato > TCP_DELACK_MIN) {
+               const struct tcp_sock *tp = tcp_sk(sk);
                int max_ato = HZ/2;
 
-               if (tp->ack.pingpong || (tp->ack.pending&TCP_ACK_PUSHED))
+               if (icsk->icsk_ack.pingpong || (icsk->icsk_ack.pending & ICSK_ACK_PUSHED))
                        max_ato = TCP_DELACK_MAX;
 
                /* Slow path, intersegment interval is "high". */
 
                /* If some rtt estimate is known, use it to bound delayed ack.
-                * Do not use tp->rto here, use results of rtt measurements
+                * Do not use inet_csk(sk)->icsk_rto here, use results of rtt measurements
                 * directly.
                 */
                if (tp->srtt) {
@@ -1874,21 +2419,22 @@ void tcp_send_delayed_ack(struct sock *sk)
        timeout = jiffies + ato;
 
        /* Use new timeout only if there wasn't a older one earlier. */
-       if (tp->ack.pending&TCP_ACK_TIMER) {
+       if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
                /* If delack timer was blocked or is about to expire,
                 * send ACK now.
                 */
-               if (tp->ack.blocked || time_before_eq(tp->ack.timeout, jiffies+(ato>>2))) {
+               if (icsk->icsk_ack.blocked ||
+                   time_before_eq(icsk->icsk_ack.timeout, jiffies + (ato >> 2))) {
                        tcp_send_ack(sk);
                        return;
                }
 
-               if (!time_before(timeout, tp->ack.timeout))
-                       timeout = tp->ack.timeout;
+               if (!time_before(timeout, icsk->icsk_ack.timeout))
+                       timeout = icsk->icsk_ack.timeout;
        }
-       tp->ack.pending |= TCP_ACK_SCHED|TCP_ACK_TIMER;
-       tp->ack.timeout = timeout;
-       sk_reset_timer(sk, &tp->delack_timer, timeout);
+       icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
+       icsk->icsk_ack.timeout = timeout;
+       sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
 }
 
 /* This routine sends an ack and also updates the window. */
@@ -1896,7 +2442,6 @@ void tcp_send_ack(struct sock *sk)
 {
        /* If we have been reset, we may not send again. */
        if (sk->sk_state != TCP_CLOSE) {
-               struct tcp_sock *tp = tcp_sk(sk);
                struct sk_buff *buff;
 
                /* We are not putting this on the write queue, so
@@ -1905,9 +2450,10 @@ void tcp_send_ack(struct sock *sk)
                 */
                buff = alloc_skb(MAX_TCP_HEADER, GFP_ATOMIC);
                if (buff == NULL) {
-                       tcp_schedule_ack(tp);
-                       tp->ack.ato = TCP_ATO_MIN;
-                       tcp_reset_xmit_timer(sk, TCP_TIME_DACK, TCP_DELACK_MAX);
+                       inet_csk_schedule_ack(sk);
+                       inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
+                       inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
+                                                 TCP_DELACK_MAX, TCP_RTO_MAX);
                        return;
                }
 
@@ -1916,13 +2462,14 @@ void tcp_send_ack(struct sock *sk)
                buff->csum = 0;
                TCP_SKB_CB(buff)->flags = TCPCB_FLAG_ACK;
                TCP_SKB_CB(buff)->sacked = 0;
-               skb_shinfo(buff)->tso_segs = 1;
-               skb_shinfo(buff)->tso_size = 0;
+               skb_shinfo(buff)->gso_segs = 1;
+               skb_shinfo(buff)->gso_size = 0;
+               skb_shinfo(buff)->gso_type = 0;
 
                /* Send it off, this clears delayed acks for us. */
-               TCP_SKB_CB(buff)->seq = TCP_SKB_CB(buff)->end_seq = tcp_acceptable_seq(sk, tp);
+               TCP_SKB_CB(buff)->seq = TCP_SKB_CB(buff)->end_seq = tcp_acceptable_seq(sk);
                TCP_SKB_CB(buff)->when = tcp_time_stamp;
-               tcp_transmit_skb(sk, buff);
+               tcp_transmit_skb(sk, buff, 0, GFP_ATOMIC);
        }
 }
 
@@ -1944,7 +2491,7 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
 
        /* We don't queue it, tcp_transmit_skb() sets ownership. */
        skb = alloc_skb(MAX_TCP_HEADER, GFP_ATOMIC);
-       if (skb == NULL) 
+       if (skb == NULL)
                return -1;
 
        /* Reserve space for headers and set control bits. */
@@ -1952,8 +2499,9 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
        skb->csum = 0;
        TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
        TCP_SKB_CB(skb)->sacked = urgent;
-       skb_shinfo(skb)->tso_segs = 1;
-       skb_shinfo(skb)->tso_size = 0;
+       skb_shinfo(skb)->gso_segs = 1;
+       skb_shinfo(skb)->gso_size = 0;
+       skb_shinfo(skb)->gso_type = 0;
 
        /* Use a previous sequence.  This should cause the other
         * end to send an ack.  Don't queue or clone SKB, just
@@ -1962,7 +2510,7 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
        TCP_SKB_CB(skb)->seq = urgent ? tp->snd_una : tp->snd_una - 1;
        TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq;
        TCP_SKB_CB(skb)->when = tcp_time_stamp;
-       return tcp_transmit_skb(sk, skb);
+       return tcp_transmit_skb(sk, skb, 0, GFP_ATOMIC);
 }
 
 int tcp_write_wakeup(struct sock *sk)
@@ -1971,7 +2519,7 @@ int tcp_write_wakeup(struct sock *sk)
                struct tcp_sock *tp = tcp_sk(sk);
                struct sk_buff *skb;
 
-               if ((skb = sk->sk_send_head) != NULL &&
+               if ((skb = tcp_send_head(sk)) != NULL &&
                    before(TCP_SKB_CB(skb)->seq, tp->snd_una+tp->snd_wnd)) {
                        int err;
                        unsigned int mss = tcp_current_mss(sk, 0);
@@ -1988,22 +2536,16 @@ int tcp_write_wakeup(struct sock *sk)
                            skb->len > mss) {
                                seg_size = min(seg_size, mss);
                                TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
-                               if (tcp_fragment(sk, skb, seg_size))
+                               if (tcp_fragment(sk, skb, seg_size, mss))
                                        return -1;
-                               /* SWS override triggered forced fragmentation.
-                                * Disable TSO, the connection is too sick. */
-                               if (sk->sk_route_caps & NETIF_F_TSO) {
-                                       sock_set_flag(sk, SOCK_NO_LARGESEND);
-                                       sk->sk_route_caps &= ~NETIF_F_TSO;
-                               }
                        } else if (!tcp_skb_pcount(skb))
-                               tcp_set_skb_tso_segs(sk, skb);
+                               tcp_set_skb_tso_segs(sk, skb, mss);
 
                        TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
                        TCP_SKB_CB(skb)->when = tcp_time_stamp;
-                       err = tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC));
+                       err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
                        if (!err) {
-                               update_send_head(sk, tp, skb);
+                               update_send_head(sk, skb);
                        }
                        return err;
                } else {
@@ -2021,35 +2563,39 @@ int tcp_write_wakeup(struct sock *sk)
  */
 void tcp_send_probe0(struct sock *sk)
 {
+       struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
        int err;
 
        err = tcp_write_wakeup(sk);
 
-       if (tp->packets_out || !sk->sk_send_head) {
+       if (tp->packets_out || !tcp_send_head(sk)) {
                /* Cancel probe timer, if it is not required. */
-               tp->probes_out = 0;
-               tp->backoff = 0;
+               icsk->icsk_probes_out = 0;
+               icsk->icsk_backoff = 0;
                return;
        }
 
        if (err <= 0) {
-               if (tp->backoff < sysctl_tcp_retries2)
-                       tp->backoff++;
-               tp->probes_out++;
-               tcp_reset_xmit_timer (sk, TCP_TIME_PROBE0, 
-                                     min(tp->rto << tp->backoff, TCP_RTO_MAX));
+               if (icsk->icsk_backoff < sysctl_tcp_retries2)
+                       icsk->icsk_backoff++;
+               icsk->icsk_probes_out++;
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
+                                         min(icsk->icsk_rto << icsk->icsk_backoff, TCP_RTO_MAX),
+                                         TCP_RTO_MAX);
        } else {
                /* If packet was not sent due to local congestion,
-                * do not backoff and do not remember probes_out.
+                * do not backoff and do not remember icsk_probes_out.
                 * Let local senders to fight for local resources.
                 *
                 * Use accumulated backoff yet.
                 */
-               if (!tp->probes_out)
-                       tp->probes_out=1;
-               tcp_reset_xmit_timer (sk, TCP_TIME_PROBE0, 
-                                     min(tp->rto << tp->backoff, TCP_RESOURCE_PROBE_INTERVAL));
+               if (!icsk->icsk_probes_out)
+                       icsk->icsk_probes_out = 1;
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
+                                         min(icsk->icsk_rto << icsk->icsk_backoff,
+                                             TCP_RESOURCE_PROBE_INTERVAL),
+                                         TCP_RTO_MAX);
        }
 }
 
@@ -2057,3 +2603,5 @@ EXPORT_SYMBOL(tcp_connect);
 EXPORT_SYMBOL(tcp_make_synack);
 EXPORT_SYMBOL(tcp_simple_retransmit);
 EXPORT_SYMBOL(tcp_sync_mss);
+EXPORT_SYMBOL(sysctl_tcp_tso_win_divisor);
+EXPORT_SYMBOL(tcp_mtup_init);