xnu-7195.101.1.tar.gz

[apple/xnu.git] / bsd / netinet / tcp_output.c
diff --git a/bsd/netinet/tcp_output.c b/bsd/netinet/tcp_output.c

index 7c1988f1f9467987fc6e330ef940e511f3ae7205..5eecbbbf5e3b1f37b723fdbba6542a19d940ea06 100644 (file)
--- a/bsd/netinet/tcp_output.c
+++ b/bsd/netinet/tcp_output.c
@@ -1,5 +1,5 @@
  /*
  /*
- * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2020 Apple Inc. All rights reserved.
   *
   * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   *
   *
   * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   *
@@ -67,7 +67,7 @@
   * Version 2.0.
   */
  
   * Version 2.0.
   */
  
-#define        _IP_VHL
+#define _IP_VHL
  
  
  #include <sys/param.h>
  
  
  #include <sys/param.h>
@@ -95,13 +95,11 @@
  #include <netinet/in_pcb.h>
  #include <netinet/ip_var.h>
  #include <mach/sdt.h>
  #include <netinet/in_pcb.h>
  #include <netinet/ip_var.h>
  #include <mach/sdt.h>
-#if INET6
  #include <netinet6/in6_pcb.h>
  #include <netinet/ip6.h>
  #include <netinet6/ip6_var.h>
  #include <netinet6/in6_pcb.h>
  #include <netinet/ip6.h>
  #include <netinet6/ip6_var.h>
-#endif
  #include <netinet/tcp.h>
  #include <netinet/tcp.h>
-#define        TCPOUTFLAGS
+#define TCPOUTFLAGS
  #include <netinet/tcp_cache.h>
  #include <netinet/tcp_fsm.h>
  #include <netinet/tcp_seq.h>
  #include <netinet/tcp_cache.h>
  #include <netinet/tcp_fsm.h>
  #include <netinet/tcp_seq.h>
@@ -120,43 +118,47 @@
  #include <netinet6/ipsec.h>
  #endif /*IPSEC*/
  
  #include <netinet6/ipsec.h>
  #endif /*IPSEC*/
  
-#if CONFIG_MACF_NET
-#include <security/mac_framework.h>
-#endif /* MAC_SOCKET */
-
-#include <netinet/lro_ext.h>
  #if MPTCP
  #include <netinet/mptcp_var.h>
  #include <netinet/mptcp.h>
  #include <netinet/mptcp_opt.h>
  #if MPTCP
  #include <netinet/mptcp_var.h>
  #include <netinet/mptcp.h>
  #include <netinet/mptcp_opt.h>
+#include <netinet/mptcp_seq.h>
  #endif
  
  #include <corecrypto/ccaes.h>
  
  #endif
  
  #include <corecrypto/ccaes.h>
  
-#define DBG_LAYER_BEG          NETDBG_CODE(DBG_NETTCP, 1)
-#define DBG_LAYER_END          NETDBG_CODE(DBG_NETTCP, 3)
-#define DBG_FNC_TCP_OUTPUT     NETDBG_CODE(DBG_NETTCP, (4 << 8) | 1)
+#define DBG_LAYER_BEG           NETDBG_CODE(DBG_NETTCP, 1)
+#define DBG_LAYER_END           NETDBG_CODE(DBG_NETTCP, 3)
+#define DBG_FNC_TCP_OUTPUT      NETDBG_CODE(DBG_NETTCP, (4 << 8) | 1)
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, path_mtu_discovery,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, path_mtu_discovery,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, path_mtu_discovery, 1,
-       "Enable Path MTU Discovery");
-
-SYSCTL_SKMEM_TCP_INT(OID_AUTO, slowstart_flightsize,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz, 1,
-       "Slow start flight size");
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, path_mtu_discovery, 1,
+    "Enable Path MTU Discovery");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, local_slowstart_flightsize,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, local_slowstart_flightsize,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz_local, 8,
-       "Slow start flight size for local networks");
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz_local, 8,
+    "Slow start flight size for local networks");
  
  
-int    tcp_do_tso = 1;
+int     tcp_do_tso = 1;
  SYSCTL_INT(_net_inet_tcp, OID_AUTO, tso, CTLFLAG_RW | CTLFLAG_LOCKED,
  SYSCTL_INT(_net_inet_tcp, OID_AUTO, tso, CTLFLAG_RW | CTLFLAG_LOCKED,
-                  &tcp_do_tso, 0, "Enable TCP Segmentation Offload");
+    &tcp_do_tso, 0, "Enable TCP Segmentation Offload");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, ecn_setup_percentage,
      CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ecn_setup_percentage, 100,
      "Max ECN setup percentage");
  
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, ecn_setup_percentage,
      CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ecn_setup_percentage, 100,
      "Max ECN setup percentage");
  
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, do_ack_compression,
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_do_ack_compression, 1,
+    "Enable TCP ACK compression (on (cell only): 1, off: 0, on (all interfaces): 2)");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, ack_compression_rate,
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ack_compression_rate, TCP_COMP_CHANGE_RATE,
+    "Rate at which we force sending new ACKs (in ms)");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, randomize_timestamps,
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_randomize_timestamps, 1,
+    "Randomize TCP timestamps to prevent tracking (on: 1, off: 0)");
+
  static int
  sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS
  {
  static int
  sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS
  {
@@ -166,8 +168,9 @@ sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS
  
         err = sysctl_io_number(req, tcp_ecn_outbound, sizeof(int32_t),
             &i, &changed);
  
         err = sysctl_io_number(req, tcp_ecn_outbound, sizeof(int32_t),
             &i, &changed);
-       if (err != 0 || req->newptr == USER_ADDR_NULL)
+       if (err != 0 || req->newptr == USER_ADDR_NULL) {
                 return err;
                 return err;
+       }
  
         if (changed) {
                 if ((tcp_ecn_outbound == 0 || tcp_ecn_outbound == 1) &&
  
         if (changed) {
                 if ((tcp_ecn_outbound == 0 || tcp_ecn_outbound == 1) &&
@@ -185,10 +188,9 @@ sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS
                         ifnet_head_lock_shared();
                         TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
                                 if (!IFNET_IS_CELLULAR(ifp)) {
                         ifnet_head_lock_shared();
                         TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
                                 if (!IFNET_IS_CELLULAR(ifp)) {
-                                       ifnet_lock_exclusive(ifp);
-                                       ifp->if_eflags &= ~IFEF_ECN_DISABLE;
-                                       ifp->if_eflags &= ~IFEF_ECN_ENABLE;
-                                       ifnet_lock_done(ifp);
+                                       if_clear_eflags(ifp,
+                                           IFEF_ECN_ENABLE |
+                                           IFEF_ECN_DISABLE);
                                 }
                         }
                         ifnet_head_done();
                                 }
                         }
                         ifnet_head_done();
@@ -200,10 +202,8 @@ sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS
                         ifnet_head_lock_shared();
                         TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
                                 if (!IFNET_IS_CELLULAR(ifp)) {
                         ifnet_head_lock_shared();
                         TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
                                 if (!IFNET_IS_CELLULAR(ifp)) {
-                                       ifnet_lock_exclusive(ifp);
-                                       ifp->if_eflags |= IFEF_ECN_ENABLE;
-                                       ifp->if_eflags &= ~IFEF_ECN_DISABLE;
-                                       ifnet_lock_done(ifp);
+                                       if_set_eflags(ifp, IFEF_ECN_ENABLE);
+                                       if_clear_eflags(ifp, IFEF_ECN_DISABLE);
                                 }
                         }
                         ifnet_head_done();
                                 }
                         }
                         ifnet_head_done();
@@ -232,52 +232,40 @@ SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_negotiate_in,
      "Initiate ECN for inbound connections");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, packetchain,
      "Initiate ECN for inbound connections");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, packetchain,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_packet_chaining, 50,
-       "Enable TCP output packet chaining");
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_packet_chaining, 50,
+    "Enable TCP output packet chaining");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, socket_unlocked_on_output,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, socket_unlocked_on_output,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_output_unlocked, 1,
-       "Unlock TCP when sending packets down to IP");
-
-SYSCTL_SKMEM_TCP_INT(OID_AUTO, rfc3390,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_do_rfc3390, 1,
-       "Calculate intial slowstart cwnd depending on MSS");
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_output_unlocked, 1,
+    "Unlock TCP when sending packets down to IP");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, min_iaj_win,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, min_iaj_win,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_min_iaj_win, MIN_IAJ_WIN,
-       "Minimum recv win based on inter-packet arrival jitter");
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_min_iaj_win, MIN_IAJ_WIN,
+    "Minimum recv win based on inter-packet arrival jitter");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, acc_iaj_react_limit,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, acc_iaj_react_limit,
-       CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_iaj_react_limit,
-       ACC_IAJ_REACT_LIMIT, "Accumulated IAJ when receiver starts to react");
-
-SYSCTL_SKMEM_TCP_INT(OID_AUTO, doautosndbuf,
-       CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_do_autosendbuf, 1,
-       "Enable send socket buffer auto-tuning");
+    CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_iaj_react_limit,
+    ACC_IAJ_REACT_LIMIT, "Accumulated IAJ when receiver starts to react");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufinc,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufinc,
-       CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_inc,
-       8 * 1024, "Increment in send socket bufffer size");
+    CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_inc,
+    8 * 1024, "Increment in send socket bufffer size");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufmax,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufmax,
-       CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_max, 512 * 1024,
-       "Maximum send socket buffer size");
-
-SYSCTL_SKMEM_TCP_INT(OID_AUTO, ack_prioritize,
-       CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_prioritize_acks, 1,
-       "Prioritize pure acks");
+    CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_max, 2 * 1024 * 1024,
+    "Maximum send socket buffer size");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, rtt_recvbg,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, rtt_recvbg,
-       CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_use_rtt_recvbg, 1,
-       "Use RTT for bg recv algorithm");
+    CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_use_rtt_recvbg, 1,
+    "Use RTT for bg recv algorithm");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, recv_throttle_minwin,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, recv_throttle_minwin,
-       CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_recv_throttle_minwin, 16 * 1024,
-       "Minimum recv win for throttling");
+    CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_recv_throttle_minwin, 16 * 1024,
+    "Minimum recv win for throttling");
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, enable_tlp,
  
  SYSCTL_SKMEM_TCP_INT(OID_AUTO, enable_tlp,
-       CTLFLAG_RW | CTLFLAG_LOCKED,
-       int32_t, tcp_enable_tlp, 1, "Enable Tail loss probe");
+    CTLFLAG_RW | CTLFLAG_LOCKED,
+    int32_t, tcp_enable_tlp, 1, "Enable Tail loss probe");
  
  static int32_t packchain_newlist = 0;
  static int32_t packchain_looped = 0;
  
  static int32_t packchain_newlist = 0;
  static int32_t packchain_looped = 0;
@@ -288,28 +276,25 @@ static int32_t packchain_sent = 0;
  extern int ipsec_bypass;
  #endif
  
  extern int ipsec_bypass;
  #endif
  
-extern int slowlink_wsize;     /* window correction for slow links */
-#if IPFIREWALL
-extern int fw_enable;          /* firewall check for packet chaining */
-extern int fw_bypass;          /* firewall check: disable packet chaining if there is rules */
-#endif /* IPFIREWALL */
+extern int slowlink_wsize;      /* window correction for slow links */
  
  extern u_int32_t dlil_filter_disable_tso_count;
  extern u_int32_t kipf_count;
  
  static int tcp_ip_output(struct socket *, struct tcpcb *, struct mbuf *,
      int, struct mbuf *, int, int, boolean_t);
  
  extern u_int32_t dlil_filter_disable_tso_count;
  extern u_int32_t kipf_count;
  
  static int tcp_ip_output(struct socket *, struct tcpcb *, struct mbuf *,
      int, struct mbuf *, int, int, boolean_t);
-static struct mbuf* tcp_send_lroacks(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th);
  static int tcp_recv_throttle(struct tcpcb *tp);
  
  static int tcp_recv_throttle(struct tcpcb *tp);
  
-static int32_t tcp_tfo_check(struct tcpcb *tp, int32_t len)
+static int32_t
+tcp_tfo_check(struct tcpcb *tp, int32_t len)
  {
         struct socket *so = tp->t_inpcb->inp_socket;
         unsigned int optlen = 0;
         unsigned int cookie_len;
  
  {
         struct socket *so = tp->t_inpcb->inp_socket;
         unsigned int optlen = 0;
         unsigned int cookie_len;
  
-       if (tp->t_flags & TF_NOOPT)
+       if (tp->t_flags & TF_NOOPT) {
                 goto fallback;
                 goto fallback;
+       }
  
         if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
             !tcp_heuristic_do_tfo(tp)) {
  
         if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
             !tcp_heuristic_do_tfo(tp)) {
@@ -318,45 +303,54 @@ static int32_t tcp_tfo_check(struct tcpcb *tp, int32_t len)
                 goto fallback;
         }
  
                 goto fallback;
         }
  
-       if (so->so_flags1 & SOF1_DATA_AUTHENTICATED)
+       if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) {
                 return len;
                 return len;
+       }
  
         optlen += TCPOLEN_MAXSEG;
  
  
         optlen += TCPOLEN_MAXSEG;
  
-       if (tp->t_flags & TF_REQ_SCALE)
+       if (tp->t_flags & TF_REQ_SCALE) {
                 optlen += 4;
                 optlen += 4;
+       }
  
  #if MPTCP
         if ((so->so_flags & SOF_MP_SUBFLOW) && mptcp_enable &&
             (tp->t_rxtshift <= mptcp_mpcap_retries ||
  
  #if MPTCP
         if ((so->so_flags & SOF_MP_SUBFLOW) && mptcp_enable &&
             (tp->t_rxtshift <= mptcp_mpcap_retries ||
-           (tptomptp(tp)->mpt_mpte->mpte_flags & MPTE_FORCE_ENABLE)))
+           (tptomptp(tp)->mpt_mpte->mpte_flags & MPTE_FORCE_ENABLE))) {
                 optlen += sizeof(struct mptcp_mpcapable_opt_common) + sizeof(mptcp_key_t);
                 optlen += sizeof(struct mptcp_mpcapable_opt_common) + sizeof(mptcp_key_t);
+       }
  #endif /* MPTCP */
  
  #endif /* MPTCP */
  
-       if (tp->t_flags & TF_REQ_TSTMP)
+       if (tp->t_flags & TF_REQ_TSTMP) {
                 optlen += TCPOLEN_TSTAMP_APPA;
                 optlen += TCPOLEN_TSTAMP_APPA;
+       }
  
  
-       if (SACK_ENABLED(tp))
+       if (SACK_ENABLED(tp)) {
                 optlen += TCPOLEN_SACK_PERMITTED;
                 optlen += TCPOLEN_SACK_PERMITTED;
+       }
  
         /* Now, decide whether to use TFO or not */
  
         /* Don't even bother trying if there is no space at all... */
  
         /* Now, decide whether to use TFO or not */
  
         /* Don't even bother trying if there is no space at all... */
-       if (MAX_TCPOPTLEN - optlen < TCPOLEN_FASTOPEN_REQ)
+       if (MAX_TCPOPTLEN - optlen < TCPOLEN_FASTOPEN_REQ) {
                 goto fallback;
                 goto fallback;
+       }
  
         cookie_len = tcp_cache_get_cookie_len(tp);
  
         cookie_len = tcp_cache_get_cookie_len(tp);
-       if (cookie_len == 0)
+       if (cookie_len == 0) {
                 /* No cookie, so we request one */
                 return 0;
                 /* No cookie, so we request one */
                 return 0;
+       }
  
         /* There is not enough space for the cookie, so we cannot do TFO */
  
         /* There is not enough space for the cookie, so we cannot do TFO */
-       if (MAX_TCPOPTLEN - optlen < cookie_len)
+       if (MAX_TCPOPTLEN - optlen < cookie_len) {
                 goto fallback;
                 goto fallback;
+       }
  
         /* Do not send SYN+data if there is more in the queue than MSS */
  
         /* Do not send SYN+data if there is more in the queue than MSS */
-       if (so->so_snd.sb_cc > (tp->t_maxopd - MAX_TCPOPTLEN))
+       if (so->so_snd.sb_cc > (tp->t_maxopd - MAX_TCPOPTLEN)) {
                 goto fallback;
                 goto fallback;
+       }
  
         /* Ok, everything looks good. We can go on and do TFO */
         return len;
  
         /* Ok, everything looks good. We can go on and do TFO */
         return len;
@@ -367,16 +361,17 @@ fallback:
  }
  
  /* Returns the number of bytes written to the TCP option-space */
  }
  
  /* Returns the number of bytes written to the TCP option-space */
-static unsigned
-tcp_tfo_write_cookie_rep(struct tcpcb *tp, unsigned optlen, u_char *opt)
+static unsigned int
+tcp_tfo_write_cookie_rep(struct tcpcb *tp, unsigned int optlen, u_char *opt)
  {
         u_char out[CCAES_BLOCK_SIZE];
         unsigned ret = 0;
         u_char *bp;
  
         if ((MAX_TCPOPTLEN - optlen) <
  {
         u_char out[CCAES_BLOCK_SIZE];
         unsigned ret = 0;
         u_char *bp;
  
         if ((MAX_TCPOPTLEN - optlen) <
-           (TCPOLEN_FASTOPEN_REQ + TFO_COOKIE_LEN_DEFAULT))
+           (TCPOLEN_FASTOPEN_REQ + TFO_COOKIE_LEN_DEFAULT)) {
                 return ret;
                 return ret;
+       }
  
         tcp_tfo_gen_cookie(tp->t_inpcb, out, sizeof(out));
  
  
         tcp_tfo_gen_cookie(tp->t_inpcb, out, sizeof(out));
  
@@ -393,16 +388,21 @@ tcp_tfo_write_cookie_rep(struct tcpcb *tp, unsigned optlen, u_char *opt)
         return ret;
  }
  
         return ret;
  }
  
-static unsigned
-tcp_tfo_write_cookie(struct tcpcb *tp, unsigned optlen, int32_t len,
-                    u_char *opt)
+static unsigned int
+tcp_tfo_write_cookie(struct tcpcb *tp, unsigned int optlen, int32_t len,
+    u_char *opt)
  {
  {
-       u_int8_t tfo_len = MAX_TCPOPTLEN - optlen - TCPOLEN_FASTOPEN_REQ;
+       uint8_t tfo_len;
         struct socket *so = tp->t_inpcb->inp_socket;
         unsigned ret = 0;
         int res;
         u_char *bp;
  
         struct socket *so = tp->t_inpcb->inp_socket;
         unsigned ret = 0;
         int res;
         u_char *bp;
  
+       if (TCPOLEN_FASTOPEN_REQ > MAX_TCPOPTLEN - optlen) {
+               return 0;
+       }
+       tfo_len = (uint8_t)(MAX_TCPOPTLEN - optlen - TCPOLEN_FASTOPEN_REQ);
+
         if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) {
                 /* If there is some data, let's track it */
                 if (len > 0) {
         if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) {
                 /* If there is some data, let's track it */
                 if (len > 0) {
@@ -449,11 +449,9 @@ tcp_tfo_write_cookie(struct tcpcb *tp, unsigned optlen, int32_t len,
  }
  
  static inline bool
  }
  
  static inline bool
-tcp_send_ecn_flags_on_syn(struct tcpcb *tp, struct socket *so)
+tcp_send_ecn_flags_on_syn(struct tcpcb *tp)
  {
  {
-       return !((tp->ecn_flags & TE_SETUPSENT ||
-           (so->so_flags & SOF_MP_SUBFLOW) ||
-           (tfo_enabled(tp))));
+       return !(tp->ecn_flags & TE_SETUPSENT);
  }
  
  void
  }
  
  void
@@ -502,8 +500,9 @@ tcp_set_ecn(struct tcpcb *tp, struct ifnet *ifp)
         return;
  
  check_heuristic:
         return;
  
  check_heuristic:
-       if (!tcp_heuristic_do_ecn(tp))
+       if (!tcp_heuristic_do_ecn(tp)) {
                 tp->ecn_flags &= ~TE_ENABLE_ECN;
                 tp->ecn_flags &= ~TE_ENABLE_ECN;
+       }
  
         /*
          * If the interface setting, system-level setting and heuristics
  
         /*
          * If the interface setting, system-level setting and heuristics
@@ -516,11 +515,37 @@ check_heuristic:
                  * Use the random value in iss for randomizing
                  * this selection
                  */
                  * Use the random value in iss for randomizing
                  * this selection
                  */
-               if ((tp->iss % 100) >= tcp_ecn_setup_percentage)
+               if ((tp->iss % 100) >= tcp_ecn_setup_percentage) {
                         tp->ecn_flags &= ~TE_ENABLE_ECN;
                         tp->ecn_flags &= ~TE_ENABLE_ECN;
+               }
         }
  }
  
         }
  }
  
+int
+tcp_flight_size(struct tcpcb *tp)
+{
+       int ret;
+
+       VERIFY(tp->sackhint.sack_bytes_acked >= 0);
+       VERIFY(tp->sackhint.sack_bytes_rexmit >= 0);
+
+       /*
+        * RFC6675, SetPipe (), SACK'd bytes are discounted. All the rest is still in-flight.
+        */
+       ret = tp->snd_nxt - tp->snd_una - tp->sackhint.sack_bytes_acked;
+
+       if (ret < 0) {
+               /*
+                * This happens when the RTO-timer fires because snd_nxt gets artificially
+                * decreased. If we then receive some SACK-blogs, sack_bytes_acked is
+                * going to be high.
+                */
+               ret = 0;
+       }
+
+       return ret;
+}
+
  /*
   * Tcp output routine: figure out what should be sent and send it.
   *
  /*
   * Tcp output routine: figure out what should be sent and send it.
   *
@@ -553,16 +578,14 @@ tcp_output(struct tcpcb *tp)
         struct inpcb *inp = tp->t_inpcb;
         struct socket *so = inp->inp_socket;
         int32_t len, recwin, sendwin, off;
         struct inpcb *inp = tp->t_inpcb;
         struct socket *so = inp->inp_socket;
         int32_t len, recwin, sendwin, off;
-       int flags, error;
+       uint8_t flags;
+       int error;
         struct mbuf *m;
         struct ip *ip = NULL;
         struct mbuf *m;
         struct ip *ip = NULL;
-       struct ipovly *ipov = NULL;
-#if INET6
         struct ip6_hdr *ip6 = NULL;
         struct ip6_hdr *ip6 = NULL;
-#endif /* INET6 */
         struct tcphdr *th;
         u_char opt[TCP_MAXOLEN];
         struct tcphdr *th;
         u_char opt[TCP_MAXOLEN];
-       unsigned ipoptlen, optlen, hdrlen;
+       unsigned int ipoptlen, optlen, hdrlen;
         int idle, sendalot, lost = 0;
         int i, sack_rxmit;
         int tso = 0;
         int idle, sendalot, lost = 0;
         int i, sack_rxmit;
         int tso = 0;
@@ -570,23 +593,17 @@ tcp_output(struct tcpcb *tp)
         tcp_seq old_snd_nxt = 0;
         struct sackhole *p;
  #if IPSEC
         tcp_seq old_snd_nxt = 0;
         struct sackhole *p;
  #if IPSEC
-       unsigned ipsec_optlen = 0;
+       unsigned int ipsec_optlen = 0;
  #endif /* IPSEC */
         int    idle_time = 0;
         struct mbuf *packetlist = NULL;
         struct mbuf *tp_inp_options = inp->inp_depend4.inp4_options;
  #endif /* IPSEC */
         int    idle_time = 0;
         struct mbuf *packetlist = NULL;
         struct mbuf *tp_inp_options = inp->inp_depend4.inp4_options;
-#if INET6
-       int isipv6 = inp->inp_vflag & INP_IPV6 ;
-#else
-       int isipv6 = 0;
-#endif
-       short packchain_listadd = 0;
+       int isipv6 = inp->inp_vflag & INP_IPV6;
+       int packchain_listadd = 0;
         int so_options = so->so_options;
         struct rtentry *rt;
         u_int32_t svc_flags = 0, allocated_len;
         int so_options = so->so_options;
         struct rtentry *rt;
         u_int32_t svc_flags = 0, allocated_len;
-       u_int32_t lro_ackmore = (tp->t_lropktlen != 0) ? 1 : 0;
-       struct mbuf *mnext = NULL;
-       int sackoptlen = 0;
+       unsigned int sackoptlen = 0;
  #if MPTCP
         boolean_t mptcp_acknow;
  #endif /* MPTCP */
  #if MPTCP
         boolean_t mptcp_acknow;
  #endif /* MPTCP */
@@ -595,6 +612,8 @@ tcp_output(struct tcpcb *tp)
         boolean_t wired = FALSE;
         boolean_t sack_rescue_rxt = FALSE;
         int sotc = so->so_traffic_class;
         boolean_t wired = FALSE;
         boolean_t sack_rescue_rxt = FALSE;
         int sotc = so->so_traffic_class;
+       boolean_t do_not_compress = FALSE;
+       boolean_t sack_rxmted = FALSE;
  
         /*
          * Determine length of data that should be transmitted,
  
         /*
          * Determine length of data that should be transmitted,
@@ -620,11 +639,13 @@ tcp_output(struct tcpcb *tp)
                  * Do some other tasks that need to be done after
                  * idle time
                  */
                  * Do some other tasks that need to be done after
                  * idle time
                  */
-               if (!SLIST_EMPTY(&tp->t_rxt_segments))
+               if (!SLIST_EMPTY(&tp->t_rxt_segments)) {
                         tcp_rxtseg_clean(tp);
                         tcp_rxtseg_clean(tp);
+               }
  
                 /* If stretch ack was auto-disabled, re-evaluate it */
                 tcp_cc_after_idle_stretchack(tp);
  
                 /* If stretch ack was auto-disabled, re-evaluate it */
                 tcp_cc_after_idle_stretchack(tp);
+               tp->t_forced_acks = TCP_FORCED_ACKS_COUNT;
         }
         tp->t_flags &= ~TF_LASTIDLE;
         if (idle) {
         }
         tp->t_flags &= ~TF_LASTIDLE;
         if (idle) {
@@ -649,25 +670,22 @@ again:
  #if MPTCP
         mptcp_acknow = FALSE;
  #endif
  #if MPTCP
         mptcp_acknow = FALSE;
  #endif
+       do_not_compress = FALSE;
  
  
-       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
+       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0, 0, 0, 0, 0);
  
  
-#if INET6
         if (isipv6) {
                 KERNEL_DEBUG(DBG_LAYER_BEG,
         if (isipv6) {
                 KERNEL_DEBUG(DBG_LAYER_BEG,
-                    ((inp->inp_fport << 16) | inp->inp_lport),
-                    (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
-                     (inp->in6p_faddr.s6_addr16[0] & 0xffff)),
-                    sendalot,0,0);
-       } else
-#endif
-
-       {
+                   ((inp->inp_fport << 16) | inp->inp_lport),
+                   (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
+                   (inp->in6p_faddr.s6_addr16[0] & 0xffff)),
+                   sendalot, 0, 0);
+       } else {
                 KERNEL_DEBUG(DBG_LAYER_BEG,
                 KERNEL_DEBUG(DBG_LAYER_BEG,
-                    ((inp->inp_fport << 16) | inp->inp_lport),
-                    (((inp->inp_laddr.s_addr & 0xffff) << 16) |
-                     (inp->inp_faddr.s_addr & 0xffff)),
-                    sendalot,0,0);
+                   ((inp->inp_fport << 16) | inp->inp_lport),
+                   (((inp->inp_laddr.s_addr & 0xffff) << 16) |
+                   (inp->inp_faddr.s_addr & 0xffff)),
+                   sendalot, 0, 0);
         }
         /*
          * If the route generation id changed, we need to check that our
         }
         /*
          * If the route generation id changed, we need to check that our
@@ -692,12 +710,14 @@ again:
  
                 if (isipv6) {
                         ia6 = ifa_foraddr6(&inp->in6p_laddr);
  
                 if (isipv6) {
                         ia6 = ifa_foraddr6(&inp->in6p_laddr);
-                       if (ia6 != NULL)
+                       if (ia6 != NULL) {
                                 found_srcaddr = 1;
                                 found_srcaddr = 1;
+                       }
                 } else {
                         ia = ifa_foraddr(inp->inp_laddr.s_addr);
                 } else {
                         ia = ifa_foraddr(inp->inp_laddr.s_addr);
-                       if (ia != NULL)
+                       if (ia != NULL) {
                                 found_srcaddr = 1;
                                 found_srcaddr = 1;
+                       }
                 }
  
                 /* check that the source address is still valid */
                 }
  
                 /* check that the source address is still valid */
@@ -725,8 +745,9 @@ again:
                                 }
                         }
  
                                 }
                         }
  
-                       if (tp->t_pktlist_head != NULL)
+                       if (tp->t_pktlist_head != NULL) {
                                 m_freem_list(tp->t_pktlist_head);
                                 m_freem_list(tp->t_pktlist_head);
+                       }
                         TCP_PKTLIST_CLEAR(tp);
  
                         /* drop connection if source address isn't available */
                         TCP_PKTLIST_CLEAR(tp);
  
                         /* drop connection if source address isn't available */
@@ -738,11 +759,13 @@ again:
                                 return 0; /* silently ignore, keep data in socket: address may be back */
                         }
                 }
                                 return 0; /* silently ignore, keep data in socket: address may be back */
                         }
                 }
-               if (ia != NULL)
+               if (ia != NULL) {
                         IFA_REMREF(&ia->ia_ifa);
                         IFA_REMREF(&ia->ia_ifa);
+               }
  
  
-               if (ia6 != NULL)
+               if (ia6 != NULL) {
                         IFA_REMREF(&ia6->ia_ifa);
                         IFA_REMREF(&ia6->ia_ifa);
+               }
  
                 /*
                  * Address is still valid; check for multipages capability
  
                 /*
                  * Address is still valid; check for multipages capability
@@ -755,8 +778,9 @@ again:
                         soif2kcl(so, (ifp->if_eflags & IFEF_2KCL));
                         tcp_set_ecn(tp, ifp);
                 }
                         soif2kcl(so, (ifp->if_eflags & IFEF_2KCL));
                         tcp_set_ecn(tp, ifp);
                 }
-               if (rt->rt_flags & RTF_UP)
+               if (rt->rt_flags & RTF_UP) {
                         RT_GENID_SYNC(rt);
                         RT_GENID_SYNC(rt);
+               }
                 /*
                  * See if we should do MTU discovery. Don't do it if:
                  *      1) it is disabled via the sysctl
                 /*
                  * See if we should do MTU discovery. Don't do it if:
                  *      1) it is disabled via the sysctl
@@ -767,10 +791,11 @@ again:
  
                 if (!path_mtu_discovery || ((rt != NULL) &&
                     (!(rt->rt_flags & RTF_UP) ||
  
                 if (!path_mtu_discovery || ((rt != NULL) &&
                     (!(rt->rt_flags & RTF_UP) ||
-                   (rt->rt_rmx.rmx_locks & RTV_MTU))))
+                   (rt->rt_rmx.rmx_locks & RTV_MTU)))) {
                         tp->t_flags &= ~TF_PMTUD;
                         tp->t_flags &= ~TF_PMTUD;
-               else
+               } else {
                         tp->t_flags |= TF_PMTUD;
                         tp->t_flags |= TF_PMTUD;
+               }
  
                 RT_UNLOCK(rt);
         }
  
                 RT_UNLOCK(rt);
         }
@@ -786,14 +811,16 @@ again:
          * snd_nxt.  There may be SACK information that allows us to avoid
          * resending already delivered data.  Adjust snd_nxt accordingly.
          */
          * snd_nxt.  There may be SACK information that allows us to avoid
          * resending already delivered data.  Adjust snd_nxt accordingly.
          */
-       if (SACK_ENABLED(tp) && SEQ_LT(tp->snd_nxt, tp->snd_max))
+       if (SACK_ENABLED(tp) && SEQ_LT(tp->snd_nxt, tp->snd_max)) {
                 tcp_sack_adjust(tp);
                 tcp_sack_adjust(tp);
+       }
         sendalot = 0;
         off = tp->snd_nxt - tp->snd_una;
         sendwin = min(tp->snd_wnd, tp->snd_cwnd);
  
         sendalot = 0;
         off = tp->snd_nxt - tp->snd_una;
         sendwin = min(tp->snd_wnd, tp->snd_cwnd);
  
-       if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0)
+       if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) {
                 sendwin = min(sendwin, slowlink_wsize);
                 sendwin = min(sendwin, slowlink_wsize);
+       }
  
         flags = tcp_outflags[tp->t_state];
         /*
  
         flags = tcp_outflags[tp->t_state];
         /*
@@ -815,9 +842,20 @@ again:
             (p = tcp_sack_output(tp, &sack_bytes_rxmt))) {
                 int32_t cwin;
  
             (p = tcp_sack_output(tp, &sack_bytes_rxmt))) {
                 int32_t cwin;
  
-               cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt;
-               if (cwin < 0)
+               if (tcp_do_better_lr) {
+                       cwin = min(tp->snd_wnd, tp->snd_cwnd) - tcp_flight_size(tp);
+                       if (cwin <= 0 && sack_rxmted == FALSE) {
+                               /* Allow to clock out at least on per period */
+                               cwin = tp->t_maxseg;
+                       }
+
+                       sack_rxmted = TRUE;
+               } else {
+                       cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt;
+               }
+               if (cwin < 0) {
                         cwin = 0;
                         cwin = 0;
+               }
                 /* Do not retransmit SACK segments beyond snd_recover */
                 if (SEQ_GT(p->end, tp->snd_recover)) {
                         /*
                 /* Do not retransmit SACK segments beyond snd_recover */
                 if (SEQ_GT(p->end, tp->snd_recover)) {
                         /*
@@ -834,10 +872,11 @@ again:
                                  */
                                 p = NULL;
                                 goto after_sack_rexmit;
                                  */
                                 p = NULL;
                                 goto after_sack_rexmit;
-                       } else
+                       } else {
                                 /* Can rexmit part of the current hole */
                                 len = ((int32_t)min(cwin,
                                 /* Can rexmit part of the current hole */
                                 len = ((int32_t)min(cwin,
-                                                  tp->snd_recover - p->rxmit));
+                                   tp->snd_recover - p->rxmit));
+                       }
                 } else {
                         len = ((int32_t)min(cwin, p->end - p->rxmit));
                 }
                 } else {
                         len = ((int32_t)min(cwin, p->end - p->rxmit));
                 }
@@ -845,6 +884,9 @@ again:
                         off = p->rxmit - tp->snd_una;
                         sack_rxmit = 1;
                         sendalot = 1;
                         off = p->rxmit - tp->snd_una;
                         sack_rxmit = 1;
                         sendalot = 1;
+                       /* Everything sent after snd_nxt will allow us to account for fast-retransmit of the retransmitted segment */
+                       tp->send_highest_sack = tp->snd_nxt;
+                       tp->t_new_dupacks = 0;
                         tcpstat.tcps_sack_rexmits++;
                         tcpstat.tcps_sack_rexmit_bytes +=
                             min(len, tp->t_maxseg);
                         tcpstat.tcps_sack_rexmits++;
                         tcpstat.tcps_sack_rexmit_bytes +=
                             min(len, tp->t_maxseg);
@@ -857,10 +899,9 @@ after_sack_rexmit:
          * Get standard flags, and add SYN or FIN if requested by 'hidden'
          * state flags.
          */
          * Get standard flags, and add SYN or FIN if requested by 'hidden'
          * state flags.
          */
-       if (tp->t_flags & TF_NEEDFIN)
+       if (tp->t_flags & TF_NEEDFIN) {
                 flags |= TH_FIN;
                 flags |= TH_FIN;
-       if (tp->t_flags & TF_NEEDSYN)
-               flags |= TH_SYN;
+       }
  
         /*
          * If in persist timeout with window of 0, send 1 byte.
  
         /*
          * If in persist timeout with window of 0, send 1 byte.
@@ -886,8 +927,9 @@ after_sack_rexmit:
                          * to send then the probe will be the FIN
                          * itself.
                          */
                          * to send then the probe will be the FIN
                          * itself.
                          */
-                       if (off < so->so_snd.sb_cc)
+                       if (off < so->so_snd.sb_cc) {
                                 flags &= ~TH_FIN;
                                 flags &= ~TH_FIN;
+                       }
                         sendwin = 1;
                 } else {
                         tp->t_timer[TCPT_PERSIST] = 0;
                         sendwin = 1;
                 } else {
                         tp->t_timer[TCPT_PERSIST] = 0;
@@ -917,18 +959,22 @@ after_sack_rexmit:
                 } else {
                         int32_t cwin;
  
                 } else {
                         int32_t cwin;
  
-                       cwin = tp->snd_cwnd -
-                           (tp->snd_nxt - tp->sack_newdata) -
-                           sack_bytes_rxmt;
-                       if (cwin < 0)
+                       if (tcp_do_better_lr) {
+                               cwin = tp->snd_cwnd - tcp_flight_size(tp);
+                       } else {
+                               cwin = tp->snd_cwnd -
+                                   (tp->snd_nxt - tp->sack_newdata) -
+                                   sack_bytes_rxmt;
+                       }
+                       if (cwin < 0) {
                                 cwin = 0;
                                 cwin = 0;
-                        /*
+                       }
+                       /*
                          * We are inside of a SACK recovery episode and are
                          * sending new data, having retransmitted all the
                          * data possible in the scoreboard.
                          */
                          * We are inside of a SACK recovery episode and are
                          * sending new data, having retransmitted all the
                          * data possible in the scoreboard.
                          */
-                       len = min(so->so_snd.sb_cc, tp->snd_wnd)
-                              - off;
+                       len = min(so->so_snd.sb_cc, tp->snd_wnd) - off;
                         /*
                          * Don't remove this (len > 0) check !
                          * We explicitly check for len > 0 here (although it
                         /*
                          * Don't remove this (len > 0) check !
                          * We explicitly check for len > 0 here (although it
@@ -962,8 +1008,9 @@ after_sack_rexmit:
                                  * must have been advanced to cover it.
                                  */
                                 if ((tp->t_flags & TF_SENTFIN) &&
                                  * must have been advanced to cover it.
                                  */
                                 if ((tp->t_flags & TF_SENTFIN) &&
-                                   tp->snd_max == tp->snd_recover)
+                                   tp->snd_max == tp->snd_recover) {
                                         tp->snd_nxt--;
                                         tp->snd_nxt--;
+                               }
  
                                 off = tp->snd_nxt - tp->snd_una;
                                 sendalot = 0;
  
                                 off = tp->snd_nxt - tp->snd_una;
                                 sendalot = 0;
@@ -991,7 +1038,7 @@ after_sack_rexmit:
                         len++;
                         if (len > 0 && tp->t_state == TCPS_SYN_SENT) {
                                 while (inp->inp_sndinprog_cnt == 0 &&
                         len++;
                         if (len > 0 && tp->t_state == TCPS_SYN_SENT) {
                                 while (inp->inp_sndinprog_cnt == 0 &&
-                                       tp->t_pktlist_head != NULL) {
+                                   tp->t_pktlist_head != NULL) {
                                         packetlist = tp->t_pktlist_head;
                                         packchain_listadd = tp->t_lastchain;
                                         packchain_sent++;
                                         packetlist = tp->t_pktlist_head;
                                         packchain_listadd = tp->t_lastchain;
                                         packchain_sent++;
@@ -1009,14 +1056,14 @@ after_sack_rexmit:
                                  * resume close
                                  */
                                 if (inp->inp_sndinprog_cnt == 0 &&
                                  * resume close
                                  */
                                 if (inp->inp_sndinprog_cnt == 0 &&
-                                       (tp->t_flags & TF_CLOSING)) {
+                                   (tp->t_flags & TF_CLOSING)) {
                                         tp->t_flags &= ~TF_CLOSING;
                                         (void) tcp_close(tp);
                                 } else {
                                         tcp_check_timer_state(tp);
                                 }
                                 KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END,
                                         tp->t_flags &= ~TF_CLOSING;
                                         (void) tcp_close(tp);
                                 } else {
                                         tcp_check_timer_state(tp);
                                 }
                                 KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END,
-                                   0,0,0,0,0);
+                                   0, 0, 0, 0, 0);
                                 return 0;
                         }
                 }
                                 return 0;
                         }
                 }
@@ -1039,11 +1086,13 @@ after_sack_rexmit:
         /*
          * Don't send a RST with data.
          */
         /*
          * Don't send a RST with data.
          */
-       if (flags & TH_RST)
+       if (flags & TH_RST) {
                 len = 0;
                 len = 0;
+       }
  
  
-       if ((flags & TH_SYN) && tp->t_state <= TCPS_SYN_SENT && tfo_enabled(tp))
+       if ((flags & TH_SYN) && tp->t_state <= TCPS_SYN_SENT && tfo_enabled(tp)) {
                 len = tcp_tfo_check(tp, len);
                 len = tcp_tfo_check(tp, len);
+       }
  
         /*
          * The check here used to be (len < 0). Some times len is zero
  
         /*
          * The check here used to be (len < 0). Some times len is zero
@@ -1069,8 +1118,9 @@ after_sack_rexmit:
                         TCP_RESET_REXMT_STATE(tp);
                         tp->snd_nxt = tp->snd_una;
                         off = 0;
                         TCP_RESET_REXMT_STATE(tp);
                         tp->snd_nxt = tp->snd_una;
                         off = 0;
-                       if (tp->t_timer[TCPT_PERSIST] == 0)
+                       if (tp->t_timer[TCPT_PERSIST] == 0) {
                                 tcp_setpersist(tp);
                                 tcp_setpersist(tp);
+                       }
                 }
         }
  
                 }
         }
  
@@ -1083,8 +1133,7 @@ after_sack_rexmit:
          *      3. our send window (slow start and congestion controlled) is
          *         larger than sent but unacknowledged data in send buffer.
          */
          *      3. our send window (slow start and congestion controlled) is
          *         larger than sent but unacknowledged data in send buffer.
          */
-       if (tcp_do_autosendbuf == 1 &&
-           !INP_WAIT_FOR_IF_FEEDBACK(inp) && !IN_FASTRECOVERY(tp) &&
+       if (!INP_WAIT_FOR_IF_FEEDBACK(inp) && !IN_FASTRECOVERY(tp) &&
             (so->so_snd.sb_flags & (SB_AUTOSIZE | SB_TRIM)) == SB_AUTOSIZE &&
             tcp_cansbgrow(&so->so_snd)) {
                 if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat &&
             (so->so_snd.sb_flags & (SB_AUTOSIZE | SB_TRIM)) == SB_AUTOSIZE &&
             tcp_cansbgrow(&so->so_snd)) {
                 if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat &&
@@ -1105,7 +1154,7 @@ after_sack_rexmit:
          *
          * TSO may only be used if we are in a pure bulk sending state.
          * The presence of TCP-MD5, SACK retransmits, SACK advertizements,
          *
          * TSO may only be used if we are in a pure bulk sending state.
          * The presence of TCP-MD5, SACK retransmits, SACK advertizements,
-        * ipfw rules and IP options, as well as disabling hardware checksum
+        * filters and IP options, as well as disabling hardware checksum
          * offload prevent using TSO.  With TSO the TCP header is the same
          * (except for the sequence number) for all generated packets.  This
          * makes it impossible to transmit any options which vary per generated
          * offload prevent using TSO.  With TSO the TCP header is the same
          * (except for the sequence number) for all generated packets.  This
          * makes it impossible to transmit any options which vary per generated
@@ -1120,22 +1169,20 @@ after_sack_rexmit:
          * Pre-calculate here as we save another lookup into the darknesses
          * of IPsec that way and can actually decide if TSO is ok.
          */
          * Pre-calculate here as we save another lookup into the darknesses
          * of IPsec that way and can actually decide if TSO is ok.
          */
-       if (ipsec_bypass == 0)
-               ipsec_optlen = ipsec_hdrsiz_tcp(tp);
+       if (ipsec_bypass == 0) {
+               ipsec_optlen = (unsigned int)ipsec_hdrsiz_tcp(tp);
+       }
  #endif
         if (len > tp->t_maxseg) {
                 if ((tp->t_flags & TF_TSO) && tcp_do_tso && hwcksum_tx &&
                     ip_use_randomid && kipf_count == 0 &&
                     dlil_filter_disable_tso_count == 0 &&
  #endif
         if (len > tp->t_maxseg) {
                 if ((tp->t_flags & TF_TSO) && tcp_do_tso && hwcksum_tx &&
                     ip_use_randomid && kipf_count == 0 &&
                     dlil_filter_disable_tso_count == 0 &&
-                   tp->rcv_numsacks == 0 && sack_rxmit == 0  &&
+                   tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
                     sack_bytes_rxmt == 0 &&
                     inp->inp_options == NULL &&
                     inp->in6p_options == NULL
  #if IPSEC
                     && ipsec_optlen == 0
                     sack_bytes_rxmt == 0 &&
                     inp->inp_options == NULL &&
                     inp->in6p_options == NULL
  #if IPSEC
                     && ipsec_optlen == 0
-#endif
-#if IPFIREWALL
-                   && (fw_enable == 0 || fw_bypass)
  #endif
                     ) {
                         tso = 1;
  #endif
                     ) {
                         tso = 1;
@@ -1145,6 +1192,8 @@ after_sack_rexmit:
                         sendalot = 1;
                         tso = 0;
                 }
                         sendalot = 1;
                         tso = 0;
                 }
+       } else {
+               tso = 0;
         }
  
         /* Send one segment or less as a tail loss probe */
         }
  
         /* Send one segment or less as a tail loss probe */
@@ -1166,19 +1215,21 @@ after_sack_rexmit:
                 int newlen = len;
                 if (tp->t_state >= TCPS_ESTABLISHED &&
                     (tp->t_mpflags & TMPF_SND_MPPRIO ||
                 int newlen = len;
                 if (tp->t_state >= TCPS_ESTABLISHED &&
                     (tp->t_mpflags & TMPF_SND_MPPRIO ||
-                    tp->t_mpflags & TMPF_SND_REM_ADDR ||
-                    tp->t_mpflags & TMPF_SND_MPFAIL ||
-                    tp->t_mpflags & TMPF_SND_KEYS ||
-                    tp->t_mpflags & TMPF_SND_JACK)) {
+                   tp->t_mpflags & TMPF_SND_REM_ADDR ||
+                   tp->t_mpflags & TMPF_SND_MPFAIL ||
+                   tp->t_mpflags & TMPF_SND_KEYS ||
+                   tp->t_mpflags & TMPF_SND_JACK)) {
                         if (len > 0) {
                                 len = 0;
                         if (len > 0) {
                                 len = 0;
+                               tso = 0;
                         }
                         /*
                          * On a new subflow, don't try to send again, because
                          * we are still waiting for the fourth ack.
                          */
                         }
                         /*
                          * On a new subflow, don't try to send again, because
                          * we are still waiting for the fourth ack.
                          */
-                       if (!(tp->t_mpflags & TMPF_PREESTABLISHED))
+                       if (!(tp->t_mpflags & TMPF_PREESTABLISHED)) {
                                 sendalot = 1;
                                 sendalot = 1;
+                       }
                         mptcp_acknow = TRUE;
                 } else {
                         mptcp_acknow = FALSE;
                         mptcp_acknow = TRUE;
                 } else {
                         mptcp_acknow = FALSE;
@@ -1195,41 +1246,21 @@ after_sack_rexmit:
  
                 if (newlen < len) {
                         len = newlen;
  
                 if (newlen < len) {
                         len = newlen;
-               }
-       }
-#endif /* MPTCP */
-
-       /*
-        * If the socket is capable of doing unordered send,
-        * pull the amount of data that can be sent from the
-        * unordered priority queues to the serial queue in
-        * the socket buffer. If bytes are not yet available
-        * in the highest priority message, we may not be able
-        * to send any new data.
-        */
-       if (so->so_flags & SOF_ENABLE_MSGS) {
-               if ((off + len) >
-                   so->so_msg_state->msg_serial_bytes) {
-                       sbpull_unordered_data(so, off, len);
-
-                       /* check if len needs to be modified */
-                       if ((off + len) >
-                           so->so_msg_state->msg_serial_bytes) {
-                               len = so->so_msg_state->msg_serial_bytes - off;
-                               if (len <= 0) {
-                                       len = 0;
-                                       tcpstat.tcps_msg_sndwaithipri++;
-                               }
+                       if (len <= tp->t_maxseg) {
+                               tso = 0;
                         }
                 }
         }
                         }
                 }
         }
+#endif /* MPTCP */
  
         if (sack_rxmit) {
  
         if (sack_rxmit) {
-               if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc))
+               if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc)) {
                         flags &= ~TH_FIN;
                         flags &= ~TH_FIN;
+               }
         } else {
         } else {
-               if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
+               if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) {
                         flags &= ~TH_FIN;
                         flags &= ~TH_FIN;
+               }
         }
         /*
          * Compare available window to amount of window
         }
         /*
          * Compare available window to amount of window
@@ -1260,18 +1291,21 @@ after_sack_rexmit:
                 if (recwin > 0 && tcp_recv_throttle(tp)) {
                         uint32_t min_iaj_win = tcp_min_iaj_win * tp->t_maxseg;
                         uint32_t bg_rwintop = tp->rcv_adv;
                 if (recwin > 0 && tcp_recv_throttle(tp)) {
                         uint32_t min_iaj_win = tcp_min_iaj_win * tp->t_maxseg;
                         uint32_t bg_rwintop = tp->rcv_adv;
-                       if (SEQ_LT(bg_rwintop, tp->rcv_nxt + min_iaj_win))
+                       if (SEQ_LT(bg_rwintop, tp->rcv_nxt + min_iaj_win)) {
                                 bg_rwintop =  tp->rcv_nxt + min_iaj_win;
                                 bg_rwintop =  tp->rcv_nxt + min_iaj_win;
+                       }
                         recwin = imin((int32_t)(bg_rwintop - tp->rcv_nxt),
                             recwin);
                         recwin = imin((int32_t)(bg_rwintop - tp->rcv_nxt),
                             recwin);
-                       if (recwin < 0)
+                       if (recwin < 0) {
                                 recwin = 0;
                                 recwin = 0;
+                       }
                 }
         }
  #endif /* TRAFFIC_MGT */
  
                 }
         }
  #endif /* TRAFFIC_MGT */
  
-       if (recwin > (int32_t)(TCP_MAXWIN << tp->rcv_scale))
+       if (recwin > (int32_t)(TCP_MAXWIN << tp->rcv_scale)) {
                 recwin = (int32_t)(TCP_MAXWIN << tp->rcv_scale);
                 recwin = (int32_t)(TCP_MAXWIN << tp->rcv_scale);
+       }
  
         if (!(so->so_flags & SOF_MP_SUBFLOW)) {
                 if (recwin < (int32_t)(tp->rcv_adv - tp->rcv_nxt)) {
  
         if (!(so->so_flags & SOF_MP_SUBFLOW)) {
                 if (recwin < (int32_t)(tp->rcv_adv - tp->rcv_nxt)) {
@@ -1279,10 +1313,12 @@ after_sack_rexmit:
                 }
         } else {
                 struct mptcb *mp_tp = tptomptp(tp);
                 }
         } else {
                 struct mptcb *mp_tp = tptomptp(tp);
+               int64_t recwin_announced = (int64_t)(mp_tp->mpt_rcvadv - mp_tp->mpt_rcvnxt);
  
                 /* Don't remove what we announced at the MPTCP-layer */
  
                 /* Don't remove what we announced at the MPTCP-layer */
-               if (recwin < (int32_t)(mp_tp->mpt_rcvadv - (uint32_t)mp_tp->mpt_rcvnxt)) {
-                       recwin = (int32_t)(mp_tp->mpt_rcvadv - (uint32_t)mp_tp->mpt_rcvnxt);
+               VERIFY(recwin_announced < INT32_MAX && recwin_announced > INT32_MIN);
+               if (recwin < (int32_t)recwin_announced) {
+                       recwin = (int32_t)recwin_announced;
                 }
         }
  
                 }
         }
  
@@ -1299,12 +1335,15 @@ after_sack_rexmit:
          *        data (receiver may be limited the window size)
          */
         if (len) {
          *        data (receiver may be limited the window size)
          */
         if (len) {
-               if (tp->t_flagsext & TF_FORCE)
+               if (tp->t_flagsext & TF_FORCE) {
                         goto send;
                         goto send;
-               if (SEQ_LT(tp->snd_nxt, tp->snd_max))
+               }
+               if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
                         goto send;
                         goto send;
-               if (sack_rxmit)
+               }
+               if (sack_rxmit) {
                         goto send;
                         goto send;
+               }
  
                 /*
                  * If this here is the first segment after SYN/ACK and TFO
  
                 /*
                  * If this here is the first segment after SYN/ACK and TFO
@@ -1313,8 +1352,9 @@ after_sack_rexmit:
                 if (tp->t_state == TCPS_SYN_RECEIVED &&
                     tfo_enabled(tp) &&
                     (tp->t_tfo_flags & TFO_F_COOKIE_VALID) &&
                 if (tp->t_state == TCPS_SYN_RECEIVED &&
                     tfo_enabled(tp) &&
                     (tp->t_tfo_flags & TFO_F_COOKIE_VALID) &&
-                   tp->snd_nxt == tp->iss + 1)
+                   tp->snd_nxt == tp->iss + 1) {
                         goto send;
                         goto send;
+               }
  
                 /*
                  * Send new data on the connection only if it is
  
                 /*
                  * Send new data on the connection only if it is
@@ -1322,8 +1362,9 @@ after_sack_rexmit:
                  */
                 if (!INP_WAIT_FOR_IF_FEEDBACK(inp) ||
                     tp->t_state != TCPS_ESTABLISHED) {
                  */
                 if (!INP_WAIT_FOR_IF_FEEDBACK(inp) ||
                     tp->t_state != TCPS_ESTABLISHED) {
-                       if (len >= tp->t_maxseg)
+                       if (len >= tp->t_maxseg) {
                                 goto send;
                                 goto send;
+                       }
  
                         if (!(tp->t_flags & TF_MORETOCOME) &&
                             (idle || tp->t_flags & TF_NODELAY ||
  
                         if (!(tp->t_flags & TF_MORETOCOME) &&
                             (idle || tp->t_flags & TF_NODELAY ||
@@ -1331,22 +1372,24 @@ after_sack_rexmit:
                             ALLOW_LIMITED_TRANSMIT(tp)) &&
                             (tp->t_flags & TF_NOPUSH) == 0 &&
                             (len + off >= so->so_snd.sb_cc ||
                             ALLOW_LIMITED_TRANSMIT(tp)) &&
                             (tp->t_flags & TF_NOPUSH) == 0 &&
                             (len + off >= so->so_snd.sb_cc ||
-                            /*
-                             * MPTCP needs to respect the DSS-mappings. So, it
-                             * may be sending data that *could* have been
-                             * coalesced, but cannot because of
-                             * mptcp_adj_sendlen().
-                             */
-                            so->so_flags & SOF_MP_SUBFLOW))
+                           /*
+                            * MPTCP needs to respect the DSS-mappings. So, it
+                            * may be sending data that *could* have been
+                            * coalesced, but cannot because of
+                            * mptcp_adj_sendlen().
+                            */
+                           so->so_flags & SOF_MP_SUBFLOW)) {
                                 goto send;
                                 goto send;
-                       if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
+                       }
+                       if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
                                 goto send;
                                 goto send;
+                       }
                 } else {
                         tcpstat.tcps_fcholdpacket++;
                 }
         }
  
                 } else {
                         tcpstat.tcps_fcholdpacket++;
                 }
         }
  
-       if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN)) {
+       if (recwin > 0) {
                 /*
                  * "adv" is the amount we can increase the window,
                  * taking into account that we are limited by
                 /*
                  * "adv" is the amount we can increase the window,
                  * taking into account that we are limited by
@@ -1354,43 +1397,79 @@ after_sack_rexmit:
                  */
                 int32_t adv, oldwin = 0;
                 adv = imin(recwin, (int)TCP_MAXWIN << tp->rcv_scale) -
                  */
                 int32_t adv, oldwin = 0;
                 adv = imin(recwin, (int)TCP_MAXWIN << tp->rcv_scale) -
-                       (tp->rcv_adv - tp->rcv_nxt);
+                   (tp->rcv_adv - tp->rcv_nxt);
  
  
-               if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt))
+               if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
                         oldwin = tp->rcv_adv - tp->rcv_nxt;
                         oldwin = tp->rcv_adv - tp->rcv_nxt;
+               }
  
  
-               if (adv >= (int32_t) (2 * tp->t_maxseg)) {
-                       /*
-                        * Update only if the resulting scaled value of
-                        * the window changed, or if there is a change in
-                        * the sequence since the last ack. This avoids
-                        * what appears as dupe ACKS (see rdar://5640997)
-                        *
-                        * If streaming is detected avoid sending too many
-                        * window updates. We will depend on the delack
-                        * timer to send a window update when needed.
-                        */
-                       if (!(tp->t_flags & TF_STRETCHACK) &&
-                               (tp->last_ack_sent != tp->rcv_nxt ||
-                               ((oldwin + adv) >> tp->rcv_scale) >
-                               (oldwin >> tp->rcv_scale))) {
-                               goto send;
+               if (tcp_ack_strategy == TCP_ACK_STRATEGY_LEGACY) {
+                       if (adv >= (int32_t) (2 * tp->t_maxseg)) {
+                               /*
+                                * Update only if the resulting scaled value of
+                                * the window changed, or if there is a change in
+                                * the sequence since the last ack. This avoids
+                                * what appears as dupe ACKS (see rdar://5640997)
+                                *
+                                * If streaming is detected avoid sending too many
+                                * window updates. We will depend on the delack
+                                * timer to send a window update when needed.
+                                *
+                                * If there is more data to read, don't send an ACK.
+                                * Otherwise we will end up sending many ACKs if the
+                                * application is doing micro-reads.
+                                */
+                               if (!(tp->t_flags & TF_STRETCHACK) &&
+                                   (tp->last_ack_sent != tp->rcv_nxt ||
+                                   ((oldwin + adv) >> tp->rcv_scale) >
+                                   (oldwin >> tp->rcv_scale))) {
+                                       goto send;
+                               }
+                       }
+               } else {
+                       if (adv >= (int32_t) (2 * tp->t_maxseg)) {
+                               /*
+                                * ACK every second full-sized segment, if the
+                                * ACK is advancing or the window becomes bigger
+                                */
+                               if (so->so_rcv.sb_cc < so->so_rcv.sb_lowat &&
+                                   (tp->last_ack_sent != tp->rcv_nxt ||
+                                   ((oldwin + adv) >> tp->rcv_scale) >
+                                   (oldwin >> tp->rcv_scale))) {
+                                       goto send;
+                               }
+                       } else if (tp->t_flags & TF_DELACK) {
+                               /*
+                                * If we delayed the ACK and the window
+                                * is not advancing by a lot (< 2MSS), ACK
+                                * immediately if the last incoming packet had
+                                * the push flag set and we emptied the buffer.
+                                *
+                                * This takes care of a sender doing small
+                                * repeated writes with Nagle enabled.
+                                */
+                               if (so->so_rcv.sb_cc == 0 &&
+                                   tp->last_ack_sent != tp->rcv_nxt &&
+                                   (tp->t_flagsext & TF_LAST_IS_PSH)) {
+                                       goto send;
+                               }
                         }
                         }
-
                 }
                 }
-               if (4 * adv >= (int32_t) so->so_rcv.sb_hiwat)
+               if (4 * adv >= (int32_t) so->so_rcv.sb_hiwat) {
                         goto send;
                         goto send;
+               }
  
                 /*
                  * Make sure that the delayed ack timer is set if
                  * we delayed sending a window update because of
                  * streaming detection.
                  */
  
                 /*
                  * Make sure that the delayed ack timer is set if
                  * we delayed sending a window update because of
                  * streaming detection.
                  */
-               if ((tp->t_flags & TF_STRETCHACK) &&
+               if (tcp_ack_strategy == TCP_ACK_STRATEGY_LEGACY &&
+                   (tp->t_flags & TF_STRETCHACK) &&
                     !(tp->t_flags & TF_DELACK)) {
                         tp->t_flags |= TF_DELACK;
                         tp->t_timer[TCPT_DELACK] =
                     !(tp->t_flags & TF_DELACK)) {
                         tp->t_flags |= TF_DELACK;
                         tp->t_timer[TCPT_DELACK] =
-                               OFFSET_FROM_START(tp, tcp_delack);
+                           OFFSET_FROM_START(tp, tcp_delack);
                 }
         }
  
                 }
         }
  
@@ -1398,24 +1477,31 @@ after_sack_rexmit:
          * Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW
          * is also a catch-all for the retransmit timer timeout case.
          */
          * Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW
          * is also a catch-all for the retransmit timer timeout case.
          */
-       if (tp->t_flags & TF_ACKNOW)
+       if (tp->t_flags & TF_ACKNOW) {
+               if (tp->t_forced_acks > 0) {
+                       tp->t_forced_acks--;
+               }
                 goto send;
                 goto send;
-       if ((flags & TH_RST) ||
-           ((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0))
+       }
+       if ((flags & TH_RST) || (flags & TH_SYN)) {
                 goto send;
                 goto send;
-       if (SEQ_GT(tp->snd_up, tp->snd_una))
+       }
+       if (SEQ_GT(tp->snd_up, tp->snd_una)) {
                 goto send;
                 goto send;
+       }
  #if MPTCP
  #if MPTCP
-       if (mptcp_acknow)
+       if (mptcp_acknow) {
                 goto send;
                 goto send;
+       }
  #endif /* MPTCP */
         /*
          * If our state indicates that FIN should be sent
          * and we have not yet done so, then we need to send.
          */
         if ((flags & TH_FIN) &&
  #endif /* MPTCP */
         /*
          * If our state indicates that FIN should be sent
          * and we have not yet done so, then we need to send.
          */
         if ((flags & TH_FIN) &&
-           (!(tp->t_flags & TF_SENTFIN) || tp->snd_nxt == tp->snd_una))
+           (!(tp->t_flags & TF_SENTFIN) || tp->snd_nxt == tp->snd_una)) {
                 goto send;
                 goto send;
+       }
         /*
          * In SACK, it is possible for tcp_output to fail to send a segment
          * after the retransmission timer has been turned off.  Make sure
         /*
          * In SACK, it is possible for tcp_output to fail to send a segment
          * after the retransmission timer has been turned off.  Make sure
@@ -1426,7 +1512,7 @@ after_sack_rexmit:
             tp->t_timer[TCPT_REXMT] == 0 &&
             tp->t_timer[TCPT_PERSIST] == 0) {
                 tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp,
             tp->t_timer[TCPT_REXMT] == 0 &&
             tp->t_timer[TCPT_PERSIST] == 0) {
                 tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp,
-                       tp->t_rxtcur);
+                   tp->t_rxtcur);
                 goto just_return;
         }
         /*
                 goto just_return;
         }
         /*
@@ -1462,7 +1548,7 @@ just_return:
          * but if there is some packets left in the packet list, send them now.
          */
         while (inp->inp_sndinprog_cnt == 0 &&
          * but if there is some packets left in the packet list, send them now.
          */
         while (inp->inp_sndinprog_cnt == 0 &&
-               tp->t_pktlist_head != NULL) {
+           tp->t_pktlist_head != NULL) {
                 packetlist = tp->t_pktlist_head;
                 packchain_listadd = tp->t_lastchain;
                 packchain_sent++;
                 packetlist = tp->t_pktlist_head;
                 packchain_listadd = tp->t_lastchain;
                 packchain_sent++;
@@ -1475,13 +1561,13 @@ just_return:
         }
         /* tcp was closed while we were in ip; resume close */
         if (inp->inp_sndinprog_cnt == 0 &&
         }
         /* tcp was closed while we were in ip; resume close */
         if (inp->inp_sndinprog_cnt == 0 &&
-               (tp->t_flags & TF_CLOSING)) {
+           (tp->t_flags & TF_CLOSING)) {
                 tp->t_flags &= ~TF_CLOSING;
                 (void) tcp_close(tp);
         } else {
                 tcp_check_timer_state(tp);
         }
                 tp->t_flags &= ~TF_CLOSING;
                 (void) tcp_close(tp);
         } else {
                 tcp_check_timer_state(tp);
         }
-       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0);
+       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
         return 0;
  
  send:
         return 0;
  
  send:
@@ -1490,10 +1576,13 @@ send:
          * the max segment size.
          */
         if (len > 0) {
          * the max segment size.
          */
         if (len > 0) {
-               if (len >= tp->t_maxseg)
+               do_not_compress = TRUE;
+
+               if (len >= tp->t_maxseg) {
                         tp->t_flags |= TF_MAXSEGSNT;
                         tp->t_flags |= TF_MAXSEGSNT;
-               else
+               } else {
                         tp->t_flags &= ~TF_MAXSEGSNT;
                         tp->t_flags &= ~TF_MAXSEGSNT;
+               }
         }
         /*
          * Before ESTABLISHED, force sending of initial options
         }
         /*
          * Before ESTABLISHED, force sending of initial options
@@ -1504,12 +1593,11 @@ send:
          *      max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MCLBYTES
          */
         optlen = 0;
          *      max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MCLBYTES
          */
         optlen = 0;
-#if INET6
-       if (isipv6)
-               hdrlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
-       else
-#endif
-               hdrlen = sizeof (struct tcpiphdr);
+       if (isipv6) {
+               hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
+       } else {
+               hdrlen = sizeof(struct tcpiphdr);
+       }
         if (flags & TH_SYN) {
                 tp->snd_nxt = tp->iss;
                 if ((tp->t_flags & TF_NOOPT) == 0) {
         if (flags & TH_SYN) {
                 tp->snd_nxt = tp->iss;
                 if ((tp->t_flags & TF_NOOPT) == 0) {
@@ -1526,9 +1614,9 @@ send:
                             (tp->t_flags & TF_RCVD_SCALE))) {
                                 *((u_int32_t *)(void *)(opt + optlen)) = htonl(
                                         TCPOPT_NOP << 24 |
                             (tp->t_flags & TF_RCVD_SCALE))) {
                                 *((u_int32_t *)(void *)(opt + optlen)) = htonl(
                                         TCPOPT_NOP << 24 |
-                                       TCPOPT_WINDOW << 16 |
-                                       TCPOLEN_WINDOW << 8 |
-                                       tp->request_r_scale);
+                                               TCPOPT_WINDOW << 16 |
+                                               TCPOLEN_WINDOW << 8 |
+                                               tp->request_r_scale);
                                 optlen += 4;
                         }
  #if MPTCP
                                 optlen += 4;
                         }
  #if MPTCP
@@ -1543,23 +1631,19 @@ send:
          * Send a timestamp and echo-reply if this is a SYN and our side
          * wants to use timestamps (TF_REQ_TSTMP is set) or both our side
          * and our peer have sent timestamps in our SYN's.
          * Send a timestamp and echo-reply if this is a SYN and our side
          * wants to use timestamps (TF_REQ_TSTMP is set) or both our side
          * and our peer have sent timestamps in our SYN's.
-        */
-       if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
-           (flags & TH_RST) == 0 &&
+        */
+       if ((tp->t_flags & (TF_REQ_TSTMP | TF_NOOPT)) == TF_REQ_TSTMP &&
+           (flags & TH_RST) == 0 &&
             ((flags & TH_ACK) == 0 ||
             ((flags & TH_ACK) == 0 ||
-            (tp->t_flags & TF_RCVD_TSTMP))) {
+           (tp->t_flags & TF_RCVD_TSTMP))) {
                 u_int32_t *lp = (u_int32_t *)(void *)(opt + optlen);
  
                 u_int32_t *lp = (u_int32_t *)(void *)(opt + optlen);
  
-               /* Form timestamp option as shown in appendix A of RFC 1323. */
-               *lp++ = htonl(TCPOPT_TSTAMP_HDR);
-               *lp++ = htonl(tcp_now);
-               *lp   = htonl(tp->ts_recent);
-               optlen += TCPOLEN_TSTAMP_APPA;
-       }
-
-       /* Note the timestamp for receive buffer autosizing */
-       if (tp->rfbuf_ts == 0 && (so->so_rcv.sb_flags & SB_AUTOSIZE))
-               tp->rfbuf_ts = tcp_now;
+               /* Form timestamp option as shown in appendix A of RFC 1323. */
+               *lp++ = htonl(TCPOPT_TSTAMP_HDR);
+               *lp++ = htonl(tcp_now + tp->t_ts_offset);
+               *lp   = htonl(tp->ts_recent);
+               optlen += TCPOLEN_TSTAMP_APPA;
+       }
  
         if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) {
                 /*
  
         if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) {
                 /*
@@ -1601,19 +1685,21 @@ send:
                         tp->t_mpflags |= TMPF_MPTCP_ACKNOW;
                 }
                 optlen = mptcp_setup_opts(tp, off, &opt[0], optlen, flags,
                         tp->t_mpflags |= TMPF_MPTCP_ACKNOW;
                 }
                 optlen = mptcp_setup_opts(tp, off, &opt[0], optlen, flags,
-                   len, &mptcp_acknow);
+                   len, &mptcp_acknow, &do_not_compress);
                 tp->t_mpflags &= ~TMPF_SEND_DSN;
         }
  #endif /* MPTCP */
  
         if (tfo_enabled(tp) && !(tp->t_flags & TF_NOOPT) &&
                 tp->t_mpflags &= ~TMPF_SEND_DSN;
         }
  #endif /* MPTCP */
  
         if (tfo_enabled(tp) && !(tp->t_flags & TF_NOOPT) &&
-           (flags & (TH_SYN | TH_ACK)) == TH_SYN)
+           (flags & (TH_SYN | TH_ACK)) == TH_SYN) {
                 optlen += tcp_tfo_write_cookie(tp, optlen, len, opt);
                 optlen += tcp_tfo_write_cookie(tp, optlen, len, opt);
+       }
  
         if (tfo_enabled(tp) &&
             (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
  
         if (tfo_enabled(tp) &&
             (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
-           (tp->t_tfo_flags & TFO_F_OFFER_COOKIE))
+           (tp->t_tfo_flags & TFO_F_OFFER_COOKIE)) {
                 optlen += tcp_tfo_write_cookie_rep(tp, optlen, opt);
                 optlen += tcp_tfo_write_cookie_rep(tp, optlen, opt);
+       }
  
         if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) {
                 /*
  
         if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) {
                 /*
@@ -1641,6 +1727,7 @@ send:
                         nsack = min(nsack, (tp->rcv_numsacks +
                             (TCP_SEND_DSACK_OPT(tp) ? 1 : 0)));
                         sackoptlen = (2 + nsack * TCPOLEN_SACK);
                         nsack = min(nsack, (tp->rcv_numsacks +
                             (TCP_SEND_DSACK_OPT(tp) ? 1 : 0)));
                         sackoptlen = (2 + nsack * TCPOLEN_SACK);
+                       VERIFY(sackoptlen < UINT8_MAX);
  
                         /*
                          * First we need to pad options so that the
  
                         /*
                          * First we need to pad options so that the
@@ -1649,12 +1736,13 @@ send:
                          */
                         padlen = (MAX_TCPOPTLEN - optlen - sackoptlen) % 4;
                         optlen += padlen;
                          */
                         padlen = (MAX_TCPOPTLEN - optlen - sackoptlen) % 4;
                         optlen += padlen;
-                       while (padlen-- > 0)
+                       while (padlen-- > 0) {
                                 *bp++ = TCPOPT_NOP;
                                 *bp++ = TCPOPT_NOP;
+                       }
  
                         tcpstat.tcps_sack_send_blocks++;
                         *bp++ = TCPOPT_SACK;
  
                         tcpstat.tcps_sack_send_blocks++;
                         *bp++ = TCPOPT_SACK;
-                       *bp++ = sackoptlen;
+                       *bp++ = (uint8_t)sackoptlen;
                         lp = (u_int32_t *)(void *)bp;
  
                         /*
                         lp = (u_int32_t *)(void *)bp;
  
                         /*
@@ -1712,7 +1800,7 @@ send:
         if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
             (tp->ecn_flags & TE_ENABLE_ECN)) {
                 if (tp->ecn_flags & TE_SETUPRECEIVED) {
         if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
             (tp->ecn_flags & TE_ENABLE_ECN)) {
                 if (tp->ecn_flags & TE_SETUPRECEIVED) {
-                       if (tcp_send_ecn_flags_on_syn(tp, so)) {
+                       if (tcp_send_ecn_flags_on_syn(tp)) {
                                 /*
                                  * Setting TH_ECE makes this an ECN-setup
                                  * SYN-ACK
                                 /*
                                  * Setting TH_ECE makes this an ECN-setup
                                  * SYN-ACK
@@ -1723,7 +1811,7 @@ send:
                                  * Record that we sent the ECN-setup and
                                  * default to setting IP ECT.
                                  */
                                  * Record that we sent the ECN-setup and
                                  * default to setting IP ECT.
                                  */
-                               tp->ecn_flags |= (TE_SETUPSENT|TE_SENDIPECT);
+                               tp->ecn_flags |= (TE_SETUPSENT | TE_SENDIPECT);
                                 tcpstat.tcps_ecn_server_setup++;
                                 tcpstat.tcps_ecn_server_success++;
                         } else {
                                 tcpstat.tcps_ecn_server_setup++;
                                 tcpstat.tcps_ecn_server_success++;
                         } else {
@@ -1754,7 +1842,7 @@ send:
                 }
         } else if ((flags & (TH_SYN | TH_ACK)) == TH_SYN &&
             (tp->ecn_flags & TE_ENABLE_ECN)) {
                 }
         } else if ((flags & (TH_SYN | TH_ACK)) == TH_SYN &&
             (tp->ecn_flags & TE_ENABLE_ECN)) {
-               if (tcp_send_ecn_flags_on_syn(tp, so)) {
+               if (tcp_send_ecn_flags_on_syn(tp)) {
                         /*
                          * Setting TH_ECE and TH_CWR makes this an
                          * ECN-setup SYN
                         /*
                          * Setting TH_ECE and TH_CWR makes this an
                          * ECN-setup SYN
@@ -1810,21 +1898,18 @@ send:
         tp->t_dsack_lseq = 0;
         tp->t_dsack_rseq = 0;
  
         tp->t_dsack_lseq = 0;
         tp->t_dsack_rseq = 0;
  
-#if INET6
-       if (isipv6)
+       if (isipv6) {
                 ipoptlen = ip6_optlen(inp);
                 ipoptlen = ip6_optlen(inp);
-       else
-#endif
-       {
+       } else {
                 if (tp_inp_options) {
                         ipoptlen = tp_inp_options->m_len -
                 if (tp_inp_options) {
                         ipoptlen = tp_inp_options->m_len -
-                               offsetof(struct ipoption, ipopt_list);
+                           offsetof(struct ipoption, ipopt_list);
                 } else {
                         ipoptlen = 0;
                 }
         }
  #if IPSEC
                 } else {
                         ipoptlen = 0;
                 }
         }
  #if IPSEC
-               ipoptlen += ipsec_optlen;
+       ipoptlen += ipsec_optlen;
  #endif
  
         /*
  #endif
  
         /*
@@ -1850,39 +1935,46 @@ send:
                         int32_t tso_maxlen;
  
                         tso_maxlen = tp->tso_max_segment_size ?
                         int32_t tso_maxlen;
  
                         tso_maxlen = tp->tso_max_segment_size ?
-                               tp->tso_max_segment_size : TCP_MAXWIN;
+                           tp->tso_max_segment_size : TCP_MAXWIN;
  
                         if (len > tso_maxlen - hdrlen - optlen) {
                                 len = tso_maxlen - hdrlen - optlen;
  
                         if (len > tso_maxlen - hdrlen - optlen) {
                                 len = tso_maxlen - hdrlen - optlen;
-                               len = len - (len % (tp->t_maxopd - optlen));
                                 sendalot = 1;
                         } else if (tp->t_flags & TF_NEEDFIN) {
                                 sendalot = 1;
                         }
                                 sendalot = 1;
                         } else if (tp->t_flags & TF_NEEDFIN) {
                                 sendalot = 1;
                         }
+
+                       if (len % (tp->t_maxopd - optlen) != 0) {
+                               len = len - (len % (tp->t_maxopd - optlen));
+                               sendalot = 1;
+                       }
                 } else {
                         len = tp->t_maxopd - optlen - ipoptlen;
                         sendalot = 1;
                 }
         }
  
                 } else {
                         len = tp->t_maxopd - optlen - ipoptlen;
                         sendalot = 1;
                 }
         }
  
-       if (max_linkhdr + hdrlen > MCLBYTES)
+       if (max_linkhdr + hdrlen > MCLBYTES) {
                 panic("tcphdr too big");
                 panic("tcphdr too big");
+       }
  
         /* Check if there is enough data in the send socket
          * buffer to start measuring bandwidth
          */
         if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 &&
  
         /* Check if there is enough data in the send socket
          * buffer to start measuring bandwidth
          */
         if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 &&
-               (tp->t_bwmeas != NULL) &&
-               (tp->t_flagsext & TF_BWMEAS_INPROGRESS) == 0) {
+           (tp->t_bwmeas != NULL) &&
+           (tp->t_flagsext & TF_BWMEAS_INPROGRESS) == 0) {
                 tp->t_bwmeas->bw_size = min(min(
                 tp->t_bwmeas->bw_size = min(min(
-                   (so->so_snd.sb_cc - (tp->snd_max - tp->snd_una)),
-                   tp->snd_cwnd), tp->snd_wnd);
+                           (so->so_snd.sb_cc - (tp->snd_max - tp->snd_una)),
+                           tp->snd_cwnd), tp->snd_wnd);
                 if (tp->t_bwmeas->bw_minsize > 0 &&
                 if (tp->t_bwmeas->bw_minsize > 0 &&
-                   tp->t_bwmeas->bw_size < tp->t_bwmeas->bw_minsize)
+                   tp->t_bwmeas->bw_size < tp->t_bwmeas->bw_minsize) {
                         tp->t_bwmeas->bw_size = 0;
                         tp->t_bwmeas->bw_size = 0;
-               if (tp->t_bwmeas->bw_maxsize > 0)
+               }
+               if (tp->t_bwmeas->bw_maxsize > 0) {
                         tp->t_bwmeas->bw_size = min(tp->t_bwmeas->bw_size,
                             tp->t_bwmeas->bw_maxsize);
                         tp->t_bwmeas->bw_size = min(tp->t_bwmeas->bw_size,
                             tp->t_bwmeas->bw_maxsize);
+               }
                 if (tp->t_bwmeas->bw_size > 0) {
                         tp->t_flagsext |= TF_BWMEAS_INPROGRESS;
                         tp->t_bwmeas->bw_start = tp->snd_max;
                 if (tp->t_bwmeas->bw_size > 0) {
                         tp->t_flagsext |= TF_BWMEAS_INPROGRESS;
                         tp->t_bwmeas->bw_start = tp->snd_max;
@@ -1897,15 +1989,19 @@ send:
          * the template for sends on this connection.
          */
         if (len) {
          * the template for sends on this connection.
          */
         if (len) {
-               tp->t_pmtud_lastseg_size = len + optlen + ipoptlen;
-               if ((tp->t_flagsext & TF_FORCE) && len == 1)
+               /* Remember what the last head-of-line packet-size was */
+               if (tp->t_pmtud_lastseg_size == 0 && tp->snd_nxt == tp->snd_una) {
+                       ASSERT(len + optlen + ipoptlen <= IP_MAXPACKET);
+                       tp->t_pmtud_lastseg_size = (uint16_t)(len + optlen + ipoptlen);
+               }
+               if ((tp->t_flagsext & TF_FORCE) && len == 1) {
                         tcpstat.tcps_sndprobe++;
                         tcpstat.tcps_sndprobe++;
-               else if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
+               } else if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
                         tcpstat.tcps_sndrexmitpack++;
                         tcpstat.tcps_sndrexmitbyte += len;
                         if (nstat_collect) {
                                 nstat_route_tx(inp->inp_route.ro_rt, 1,
                         tcpstat.tcps_sndrexmitpack++;
                         tcpstat.tcps_sndrexmitbyte += len;
                         if (nstat_collect) {
                                 nstat_route_tx(inp->inp_route.ro_rt, 1,
-                                       len, NSTAT_TX_FLAG_RETRANSMIT);
+                                   len, NSTAT_TX_FLAG_RETRANSMIT);
                                 INP_ADD_STAT(inp, cell, wifi, wired,
                                     txpackets, 1);
                                 INP_ADD_STAT(inp, cell, wifi, wired,
                                 INP_ADD_STAT(inp, cell, wifi, wired,
                                     txpackets, 1);
                                 INP_ADD_STAT(inp, cell, wifi, wired,
@@ -1948,24 +2044,24 @@ send:
  
                 /* minimum length we are going to allocate */
                 allocated_len = MHLEN;
  
                 /* minimum length we are going to allocate */
                 allocated_len = MHLEN;
-               if (MHLEN < hdrlen + max_linkhdr) {
+               if (MHLEN < hdrlen + max_linkhdr) {
                         MGETHDR(m, M_DONTWAIT, MT_HEADER);
                         if (m == NULL) {
                                 error = ENOBUFS;
                                 goto out;
                         }
                         MGETHDR(m, M_DONTWAIT, MT_HEADER);
                         if (m == NULL) {
                                 error = ENOBUFS;
                                 goto out;
                         }
-                       MCLGET(m, M_DONTWAIT);
-                       if ((m->m_flags & M_EXT) == 0) {
-                               m_freem(m);
-                               error = ENOBUFS;
-                               goto out;
-                       }
+                       MCLGET(m, M_DONTWAIT);
+                       if ((m->m_flags & M_EXT) == 0) {
+                               m_freem(m);
+                               error = ENOBUFS;
+                               goto out;
+                       }
                         m->m_data += max_linkhdr;
                         m->m_len = hdrlen;
                         allocated_len = MCLBYTES;
                 }
                 if (len <= allocated_len - hdrlen - max_linkhdr) {
                         m->m_data += max_linkhdr;
                         m->m_len = hdrlen;
                         allocated_len = MCLBYTES;
                 }
                 if (len <= allocated_len - hdrlen - max_linkhdr) {
-                       if (m == NULL) {
+                       if (m == NULL) {
                                 VERIFY(allocated_len <= MHLEN);
                                 MGETHDR(m, M_DONTWAIT, MT_HEADER);
                                 if (m == NULL) {
                                 VERIFY(allocated_len <= MHLEN);
                                 MGETHDR(m, M_DONTWAIT, MT_HEADER);
                                 if (m == NULL) {
@@ -1977,7 +2073,9 @@ send:
                         }
                         /* makes sure we still have data left to be sent at this point */
                         if (so->so_snd.sb_mb == NULL || off < 0) {
                         }
                         /* makes sure we still have data left to be sent at this point */
                         if (so->so_snd.sb_mb == NULL || off < 0) {
-                               if (m != NULL)  m_freem(m);
+                               if (m != NULL) {
+                                       m_freem(m);
+                               }
                                 error = 0; /* should we return an error? */
                                 goto out;
                         }
                                 error = 0; /* should we return an error? */
                                 goto out;
                         }
@@ -2021,10 +2119,10 @@ send:
                                  * it acted on to fullfill the current request,
                                  * whether a valid 'hint' was passed in or not.
                                  */
                                  * it acted on to fullfill the current request,
                                  * whether a valid 'hint' was passed in or not.
                                  */
-                               if ((m = m_copym_with_hdrs(so->so_snd.sb_mb,
+                               if ((m = m_copym_with_hdrs(so->so_snd.sb_mb,
                                     off, len, M_DONTWAIT, NULL, NULL,
                                     copymode)) == NULL) {
                                     off, len, M_DONTWAIT, NULL, NULL,
                                     copymode)) == NULL) {
-                                       error = ENOBUFS;
+                                       error = ENOBUFS;
                                         goto out;
                                 }
                                 m->m_data += max_linkhdr;
                                         goto out;
                                 }
                                 m->m_data += max_linkhdr;
@@ -2039,19 +2137,21 @@ send:
                  *
                  * On SYN-segments we should not add the PUSH-flag.
                  */
                  *
                  * On SYN-segments we should not add the PUSH-flag.
                  */
-               if (off + len == so->so_snd.sb_cc && !(flags & TH_SYN))
+               if (off + len == so->so_snd.sb_cc && !(flags & TH_SYN)) {
                         flags |= TH_PUSH;
                         flags |= TH_PUSH;
+               }
         } else {
         } else {
-               if (tp->t_flags & TF_ACKNOW)
+               if (tp->t_flags & TF_ACKNOW) {
                         tcpstat.tcps_sndacks++;
                         tcpstat.tcps_sndacks++;
-               else if (flags & (TH_SYN|TH_FIN|TH_RST))
+               } else if (flags & (TH_SYN | TH_FIN | TH_RST)) {
                         tcpstat.tcps_sndctrl++;
                         tcpstat.tcps_sndctrl++;
-               else if (SEQ_GT(tp->snd_up, tp->snd_una))
+               } else if (SEQ_GT(tp->snd_up, tp->snd_una)) {
                         tcpstat.tcps_sndurg++;
                         tcpstat.tcps_sndurg++;
-               else
+               } else {
                         tcpstat.tcps_sndwinup++;
                         tcpstat.tcps_sndwinup++;
+               }
  
  
-               MGETHDR(m, M_DONTWAIT, MT_HEADER);      /* MAC-OK */
+               MGETHDR(m, M_DONTWAIT, MT_HEADER);      /* MAC-OK */
                 if (m == NULL) {
                         error = ENOBUFS;
                         goto out;
                 if (m == NULL) {
                         error = ENOBUFS;
                         goto out;
@@ -2068,16 +2168,36 @@ send:
                 m->m_len = hdrlen;
         }
         m->m_pkthdr.rcvif = 0;
                 m->m_len = hdrlen;
         }
         m->m_pkthdr.rcvif = 0;
-#if CONFIG_MACF_NET
-       mac_mbuf_label_associate_inpcb(inp, m);
-#endif
-#if INET6
+
+       /* Any flag other than pure-ACK: Do not compress! */
+       if (flags & ~(TH_ACK)) {
+               do_not_compress = TRUE;
+       }
+
+       if (tp->rcv_scale == 0) {
+               do_not_compress = TRUE;
+       }
+
+       if (do_not_compress || (tcp_do_ack_compression == 1 && !cell) || __improbable(!tcp_do_ack_compression)) {
+               m->m_pkthdr.comp_gencnt = 0;
+       } else {
+               if (TSTMP_LT(tp->t_comp_lastinc + tcp_ack_compression_rate, tcp_now)) {
+                       tp->t_comp_gencnt++;
+                       /* 0 means no compression, thus jump this */
+                       if (tp->t_comp_gencnt <= TCP_ACK_COMPRESSION_DUMMY) {
+                               tp->t_comp_gencnt = TCP_ACK_COMPRESSION_DUMMY + 1;
+                       }
+                       tp->t_comp_lastinc = tcp_now;
+               }
+               m->m_pkthdr.comp_gencnt = tp->t_comp_gencnt;
+       }
+
         if (isipv6) {
                 ip6 = mtod(m, struct ip6_hdr *);
                 th = (struct tcphdr *)(void *)(ip6 + 1);
                 tcp_fillheaders(tp, ip6, th);
                 if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len &&
         if (isipv6) {
                 ip6 = mtod(m, struct ip6_hdr *);
                 th = (struct tcphdr *)(void *)(ip6 + 1);
                 tcp_fillheaders(tp, ip6, th);
                 if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len &&
-                       !SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) {
+                   !SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) {
                         ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
                 }
                 svc_flags |= PKT_SCF_IPV6;
                         ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
                 }
                 svc_flags |= PKT_SCF_IPV6;
@@ -2085,11 +2205,8 @@ send:
                 m_pftag(m)->pftag_hdr = (void *)ip6;
                 m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET6;
  #endif /* PF_ECN */
                 m_pftag(m)->pftag_hdr = (void *)ip6;
                 m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET6;
  #endif /* PF_ECN */
-       } else
-#endif /* INET6 */
-       {
+       } else {
                 ip = mtod(m, struct ip *);
                 ip = mtod(m, struct ip *);
-               ipov = (struct ipovly *)ip;
                 th = (struct tcphdr *)(void *)(ip + 1);
                 /* this picks up the pseudo header (w/o the length) */
                 tcp_fillheaders(tp, ip, th);
                 th = (struct tcphdr *)(void *)(ip + 1);
                 /* this picks up the pseudo header (w/o the length) */
                 tcp_fillheaders(tp, ip, th);
@@ -2110,8 +2227,9 @@ send:
          * If resending a FIN, be sure not to use a new sequence number.
          */
         if ((flags & TH_FIN) && (tp->t_flags & TF_SENTFIN) &&
          * If resending a FIN, be sure not to use a new sequence number.
          */
         if ((flags & TH_FIN) && (tp->t_flags & TF_SENTFIN) &&
-           tp->snd_nxt == tp->snd_max)
+           tp->snd_nxt == tp->snd_max) {
                 tp->snd_nxt--;
                 tp->snd_nxt--;
+       }
         /*
          * If we are doing retransmissions, then snd_nxt will
          * not reflect the first unsent octet.  For ACK only
         /*
          * If we are doing retransmissions, then snd_nxt will
          * not reflect the first unsent octet.  For ACK only
@@ -2129,7 +2247,7 @@ send:
          * retransmissions.
          */
         if (sack_rxmit == 0) {
          * retransmissions.
          */
         if (sack_rxmit == 0) {
-               if (len || (flags & (TH_SYN|TH_FIN)) ||
+               if (len || (flags & (TH_SYN | TH_FIN)) ||
                     tp->t_timer[TCPT_PERSIST]) {
                         th->th_seq = htonl(tp->snd_nxt);
                         if (len > 0) {
                     tp->t_timer[TCPT_PERSIST]) {
                         th->th_seq = htonl(tp->snd_nxt);
                         if (len > 0) {
@@ -2141,9 +2259,10 @@ send:
                                         tcp_rxtseg_insert(tp, tp->snd_nxt,
                                             (tp->snd_nxt + len - 1));
                                 }
                                         tcp_rxtseg_insert(tp, tp->snd_nxt,
                                             (tp->snd_nxt + len - 1));
                                 }
-                               if (len > 0)
+                               if (len > 0) {
                                         m->m_pkthdr.pkt_flags |=
                                             PKTF_TCP_REXMT;
                                         m->m_pkthdr.pkt_flags |=
                                             PKTF_TCP_REXMT;
+                               }
                         }
                 } else {
                         th->th_seq = htonl(tp->snd_max);
                         }
                 } else {
                         th->th_seq = htonl(tp->snd_max);
@@ -2163,10 +2282,11 @@ send:
         tp->last_ack_sent = tp->rcv_nxt;
         if (optlen) {
                 bcopy(opt, th + 1, optlen);
         tp->last_ack_sent = tp->rcv_nxt;
         if (optlen) {
                 bcopy(opt, th + 1, optlen);
-               th->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
+               th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
         }
         th->th_flags = flags;
         }
         th->th_flags = flags;
-       th->th_win = htons((u_short) (recwin>>tp->rcv_scale));
+       th->th_win = htons((u_short) (recwin >> tp->rcv_scale));
+       tp->t_last_recwin = recwin;
         if (!(so->so_flags & SOF_MP_SUBFLOW)) {
                 if (recwin > 0 && SEQ_LT(tp->rcv_adv, tp->rcv_nxt + recwin)) {
                         tp->rcv_adv = tp->rcv_nxt + recwin;
         if (!(so->so_flags & SOF_MP_SUBFLOW)) {
                 if (recwin > 0 && SEQ_LT(tp->rcv_adv, tp->rcv_nxt + recwin)) {
                         tp->rcv_adv = tp->rcv_nxt + recwin;
@@ -2177,8 +2297,8 @@ send:
                         tp->rcv_adv = tp->rcv_nxt + recwin;
                 }
  
                         tp->rcv_adv = tp->rcv_nxt + recwin;
                 }
  
-               if (recwin > 0 && SEQ_LT(mp_tp->mpt_rcvadv, (uint32_t)mp_tp->mpt_rcvnxt + recwin)) {
-                       mp_tp->mpt_rcvadv = (uint32_t)mp_tp->mpt_rcvnxt + recwin;
+               if (recwin > 0 && MPTCP_SEQ_LT(mp_tp->mpt_rcvadv, mp_tp->mpt_rcvnxt + recwin)) {
+                       mp_tp->mpt_rcvadv = mp_tp->mpt_rcvnxt + recwin;
                 }
         }
  
                 }
         }
  
@@ -2190,10 +2310,11 @@ send:
          * to read more data then can be buffered prior to transmitting on
          * the connection.
          */
          * to read more data then can be buffered prior to transmitting on
          * the connection.
          */
-       if (th->th_win == 0)
+       if (th->th_win == 0) {
                 tp->t_flags |= TF_RXWIN0SENT;
                 tp->t_flags |= TF_RXWIN0SENT;
-       else
+       } else {
                 tp->t_flags &= ~TF_RXWIN0SENT;
                 tp->t_flags &= ~TF_RXWIN0SENT;
+       }
  
         if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
                 th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt));
  
         if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
                 th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt));
@@ -2205,7 +2326,7 @@ send:
                  * so that it doesn't drift into the send window on sequence
                  * number wraparound.
                  */
                  * so that it doesn't drift into the send window on sequence
                  * number wraparound.
                  */
-               tp->snd_up = tp->snd_una;               /* drag it along */
+               tp->snd_up = tp->snd_una;               /* drag it along */
         }
  
         /*
         }
  
         /*
@@ -2221,10 +2342,10 @@ send:
          */
         if (tp->t_state != TCPS_ESTABLISHED &&
             (tp->t_state == TCPS_CLOSING || tp->t_state == TCPS_TIME_WAIT
          */
         if (tp->t_state != TCPS_ESTABLISHED &&
             (tp->t_state == TCPS_CLOSING || tp->t_state == TCPS_TIME_WAIT
-           || tp->t_state == TCPS_LAST_ACK || (th->th_flags & TH_RST)))
+           || tp->t_state == TCPS_LAST_ACK || (th->th_flags & TH_RST))) {
                 m->m_pkthdr.pkt_flags |= PKTF_LAST_PKT;
                 m->m_pkthdr.pkt_flags |= PKTF_LAST_PKT;
+       }
  
  
-#if INET6
         if (isipv6) {
                 /*
                  * ip6_plen is not need to be filled now, and will be filled
         if (isipv6) {
                 /*
                  * ip6_plen is not need to be filled now, and will be filled
@@ -2232,18 +2353,17 @@ send:
                  */
                 m->m_pkthdr.csum_flags = CSUM_TCPIPV6;
                 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
                  */
                 m->m_pkthdr.csum_flags = CSUM_TCPIPV6;
                 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
-               if (len + optlen)
+               if (len + optlen) {
                         th->th_sum = in_addword(th->th_sum,
                         th->th_sum = in_addword(th->th_sum,
-                               htons((u_short)(optlen + len)));
-       }
-       else
-#endif /* INET6 */
-       {
+                           htons((u_short)(optlen + len)));
+               }
+       } else {
                 m->m_pkthdr.csum_flags = CSUM_TCP;
                 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
                 m->m_pkthdr.csum_flags = CSUM_TCP;
                 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
-               if (len + optlen)
+               if (len + optlen) {
                         th->th_sum = in_addword(th->th_sum,
                         th->th_sum = in_addword(th->th_sum,
-                               htons((u_short)(optlen + len)));
+                           htons((u_short)(optlen + len)));
+               }
         }
  
         /*
         }
  
         /*
@@ -2251,12 +2371,11 @@ send:
          * The TCP pseudo header checksum is always provided.
          */
         if (tso) {
          * The TCP pseudo header checksum is always provided.
          */
         if (tso) {
-#if INET6
-               if (isipv6)
+               if (isipv6) {
                         m->m_pkthdr.csum_flags |= CSUM_TSO_IPV6;
                         m->m_pkthdr.csum_flags |= CSUM_TSO_IPV6;
-               else
-#endif /* INET6 */
+               } else {
                         m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4;
                         m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4;
+               }
  
                 m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen;
         } else {
  
                 m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen;
         } else {
@@ -2274,17 +2393,19 @@ send:
                 /*
                  * Advance snd_nxt over sequence space of this segment.
                  */
                 /*
                  * Advance snd_nxt over sequence space of this segment.
                  */
-               if (flags & (TH_SYN|TH_FIN)) {
-                       if (flags & TH_SYN)
+               if (flags & (TH_SYN | TH_FIN)) {
+                       if (flags & TH_SYN) {
                                 tp->snd_nxt++;
                                 tp->snd_nxt++;
+                       }
                         if ((flags & TH_FIN) &&
                         if ((flags & TH_FIN) &&
-                               !(tp->t_flags & TF_SENTFIN)) {
+                           !(tp->t_flags & TF_SENTFIN)) {
                                 tp->snd_nxt++;
                                 tp->t_flags |= TF_SENTFIN;
                         }
                 }
                                 tp->snd_nxt++;
                                 tp->t_flags |= TF_SENTFIN;
                         }
                 }
-               if (sack_rxmit)
+               if (sack_rxmit) {
                         goto timer;
                         goto timer;
+               }
                 if (sack_rescue_rxt == TRUE) {
                         tp->snd_nxt = old_snd_nxt;
                         sack_rescue_rxt = FALSE;
                 if (sack_rescue_rxt == TRUE) {
                         tp->snd_nxt = old_snd_nxt;
                         sack_rescue_rxt = FALSE;
@@ -2316,14 +2437,14 @@ send:
  timer:
                 if (tp->t_timer[TCPT_REXMT] == 0 &&
                     ((sack_rxmit && tp->snd_nxt != tp->snd_max) ||
  timer:
                 if (tp->t_timer[TCPT_REXMT] == 0 &&
                     ((sack_rxmit && tp->snd_nxt != tp->snd_max) ||
-                       tp->snd_nxt != tp->snd_una || (flags & TH_FIN))) {
+                   tp->snd_nxt != tp->snd_una || (flags & TH_FIN))) {
                         if (tp->t_timer[TCPT_PERSIST]) {
                                 tp->t_timer[TCPT_PERSIST] = 0;
                                 tp->t_persist_stop = 0;
                                 TCP_RESET_REXMT_STATE(tp);
                         }
                         tp->t_timer[TCPT_REXMT] =
                         if (tp->t_timer[TCPT_PERSIST]) {
                                 tp->t_timer[TCPT_PERSIST] = 0;
                                 tp->t_persist_stop = 0;
                                 TCP_RESET_REXMT_STATE(tp);
                         }
                         tp->t_timer[TCPT_REXMT] =
-                               OFFSET_FROM_START(tp, tp->t_rxtcur);
+                           OFFSET_FROM_START(tp, tp->t_rxtcur);
                 }
  
                 /*
                 }
  
                 /*
@@ -2338,27 +2459,39 @@ timer:
                     tp->snd_nxt == tp->snd_max &&
                     SEQ_GT(tp->snd_nxt, tp->snd_una) &&
                     tp->t_rxtshift == 0 &&
                     tp->snd_nxt == tp->snd_max &&
                     SEQ_GT(tp->snd_nxt, tp->snd_una) &&
                     tp->t_rxtshift == 0 &&
-                   (tp->t_flagsext & (TF_SENT_TLPROBE|TF_PKTS_REORDERED)) == 0) {
-                       u_int32_t pto, srtt;
-
-                       /*
-                        * Using SRTT alone to set PTO can cause spurious
-                        * retransmissions on wireless networks where there
-                        * is a lot of variance in RTT. Taking variance
-                        * into account will avoid this.
-                        */
-                       srtt = tp->t_srtt >> TCP_RTT_SHIFT;
-                       pto = ((TCP_REXMTVAL(tp)) * 3) >> 1;
-                       pto = max (2 * srtt, pto);
-                       if ((tp->snd_max - tp->snd_una) == tp->t_maxseg)
-                               pto = max(pto,
-                                   (((3 * pto) >> 2) + tcp_delack * 2));
-                       else
-                               pto = max(10, pto);
+                   (tp->t_flagsext & (TF_SENT_TLPROBE | TF_PKTS_REORDERED)) == 0) {
+                       uint32_t pto, srtt;
+
+                       if (tcp_do_better_lr) {
+                               srtt = tp->t_srtt >> TCP_RTT_SHIFT;
+                               pto = 2 * srtt;
+                               if ((tp->snd_max - tp->snd_una) <= tp->t_maxseg) {
+                                       pto += tcp_delack;
+                               } else {
+                                       pto += 2;
+                               }
+                       } else {
+                               /*
+                                * Using SRTT alone to set PTO can cause spurious
+                                * retransmissions on wireless networks where there
+                                * is a lot of variance in RTT. Taking variance
+                                * into account will avoid this.
+                                */
+                               srtt = tp->t_srtt >> TCP_RTT_SHIFT;
+                               pto = ((TCP_REXMTVAL(tp)) * 3) >> 1;
+                               pto = max(2 * srtt, pto);
+                               if ((tp->snd_max - tp->snd_una) == tp->t_maxseg) {
+                                       pto = max(pto,
+                                           (((3 * pto) >> 2) + tcp_delack * 2));
+                               } else {
+                                       pto = max(10, pto);
+                               }
+                       }
  
                         /* if RTO is less than PTO, choose RTO instead */
  
                         /* if RTO is less than PTO, choose RTO instead */
-                       if (tp->t_rxtcur < pto)
+                       if (tp->t_rxtcur < pto) {
                                 pto = tp->t_rxtcur;
                                 pto = tp->t_rxtcur;
+                       }
  
                         tp->t_timer[TCPT_PTO] = OFFSET_FROM_START(tp, pto);
                 }
  
                         tp->t_timer[TCPT_PTO] = OFFSET_FROM_START(tp, pto);
                 }
@@ -2368,10 +2501,11 @@ timer:
                  * persist mode (no window) we do not update snd_nxt.
                  */
                 int xlen = len;
                  * persist mode (no window) we do not update snd_nxt.
                  */
                 int xlen = len;
-               if (flags & TH_SYN)
+               if (flags & TH_SYN) {
                         ++xlen;
                         ++xlen;
+               }
                 if ((flags & TH_FIN) &&
                 if ((flags & TH_FIN) &&
-                       !(tp->t_flags & TF_SENTFIN)) {
+                   !(tp->t_flags & TF_SENTFIN)) {
                         ++xlen;
                         tp->t_flags |= TF_SENTFIN;
                 }
                         ++xlen;
                         tp->t_flags |= TF_SENTFIN;
                 }
@@ -2385,8 +2519,9 @@ timer:
         /*
          * Trace.
          */
         /*
          * Trace.
          */
-       if (so_options & SO_DEBUG)
+       if (so_options & SO_DEBUG) {
                 tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
                 tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
+       }
  #endif
  
         /*
  #endif
  
         /*
@@ -2395,7 +2530,6 @@ timer:
          * to handle ttl and tos; we could keep them in
          * the template, but need a way to checksum without them.
          */
          * to handle ttl and tos; we could keep them in
          * the template, but need a way to checksum without them.
          */
-#if INET6
         /*
          * m->m_pkthdr.len should have been set before cksum calcuration,
          * because in6_cksum() need it.
         /*
          * m->m_pkthdr.len should have been set before cksum calcuration,
          * because in6_cksum() need it.
@@ -2415,18 +2549,17 @@ timer:
                     ((inp->inp_fport << 16) | inp->inp_lport),
                     (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
                     (inp->in6p_faddr.s6_addr16[0] & 0xffff)),
                     ((inp->inp_fport << 16) | inp->inp_lport),
                     (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
                     (inp->in6p_faddr.s6_addr16[0] & 0xffff)),
-                   sendalot,0,0);
-       } else
-#endif /* INET6 */
-       {
-               ip->ip_len = m->m_pkthdr.len;
-               ip->ip_ttl = inp->inp_ip_ttl;   /* XXX */
+                   sendalot, 0, 0);
+       } else {
+               ASSERT(m->m_pkthdr.len <= IP_MAXPACKET);
+               ip->ip_len = (u_short)m->m_pkthdr.len;
+               ip->ip_ttl = inp->inp_ip_ttl;   /* XXX */
                 ip->ip_tos |= (inp->inp_ip_tos & ~IPTOS_ECN_MASK);/* XXX */
                 ip->ip_tos |= (inp->inp_ip_tos & ~IPTOS_ECN_MASK);/* XXX */
-               KERNEL_DEBUG(DBG_LAYER_BEG,
-                   ((inp->inp_fport << 16) | inp->inp_lport),
-                   (((inp->inp_laddr.s_addr & 0xffff) << 16) |
-                   (inp->inp_faddr.s_addr & 0xffff)), 0,0,0);
-       }
+               KERNEL_DEBUG(DBG_LAYER_BEG,
+                   ((inp->inp_fport << 16) | inp->inp_lport),
+                   (((inp->inp_laddr.s_addr & 0xffff) << 16) |
+                   (inp->inp_faddr.s_addr & 0xffff)), 0, 0, 0);
+       }
  
         /*
          * See if we should do MTU discovery.
  
         /*
          * See if we should do MTU discovery.
@@ -2437,35 +2570,36 @@ timer:
          *      4) the MTU is not locked (if it is, then discovery has been
          *         disabled for that route)
          */
          *      4) the MTU is not locked (if it is, then discovery has been
          *         disabled for that route)
          */
-#if INET6
-       if (!isipv6)
-#endif /* INET6 */
-               if (path_mtu_discovery && (tp->t_flags & TF_PMTUD))
+       if (!isipv6) {
+               if (path_mtu_discovery && (tp->t_flags & TF_PMTUD)) {
                         ip->ip_off |= IP_DF;
                         ip->ip_off |= IP_DF;
+               }
+       }
  
  #if NECP
         {
                 necp_kernel_policy_id policy_id;
                 necp_kernel_policy_id skip_policy_id;
                 u_int32_t route_rule_id;
  
  #if NECP
         {
                 necp_kernel_policy_id policy_id;
                 necp_kernel_policy_id skip_policy_id;
                 u_int32_t route_rule_id;
-               if (!necp_socket_is_allowed_to_send_recv(inp, NULL, &policy_id, &route_rule_id, &skip_policy_id)) {
+               u_int32_t pass_flags;
+               if (!necp_socket_is_allowed_to_send_recv(inp, NULL, 0, &policy_id, &route_rule_id, &skip_policy_id, &pass_flags)) {
                         TCP_LOG_DROP_NECP(isipv6 ? (void *)ip6 : (void *)ip, th, tp, true);
                         m_freem(m);
                         error = EHOSTUNREACH;
                         goto out;
                 }
                         TCP_LOG_DROP_NECP(isipv6 ? (void *)ip6 : (void *)ip, th, tp, true);
                         m_freem(m);
                         error = EHOSTUNREACH;
                         goto out;
                 }
-               necp_mark_packet_from_socket(m, inp, policy_id, route_rule_id, skip_policy_id);
+               necp_mark_packet_from_socket(m, inp, policy_id, route_rule_id, skip_policy_id, pass_flags);
  
                 if (net_qos_policy_restricted != 0) {
  
                 if (net_qos_policy_restricted != 0) {
-                       necp_socket_update_qos_marking(inp, inp->inp_route.ro_rt,
-                           NULL, route_rule_id);
+                       necp_socket_update_qos_marking(inp, inp->inp_route.ro_rt, route_rule_id);
                 }
         }
  #endif /* NECP */
  
  #if IPSEC
                 }
         }
  #endif /* NECP */
  
  #if IPSEC
-       if (inp->inp_sp != NULL)
+       if (inp->inp_sp != NULL) {
                 ipsec_setsocket(m, so);
                 ipsec_setsocket(m, so);
+       }
  #endif /*IPSEC*/
  
         /*
  #endif /*IPSEC*/
  
         /*
@@ -2482,10 +2616,11 @@ timer:
         m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC | PKTF_FLOW_ADV);
         m->m_pkthdr.pkt_proto = IPPROTO_TCP;
         m->m_pkthdr.tx_tcp_pid = so->last_pid;
         m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC | PKTF_FLOW_ADV);
         m->m_pkthdr.pkt_proto = IPPROTO_TCP;
         m->m_pkthdr.tx_tcp_pid = so->last_pid;
-       if (so->so_flags & SOF_DELEGATED)
+       if (so->so_flags & SOF_DELEGATED) {
                 m->m_pkthdr.tx_tcp_e_pid = so->e_pid;
                 m->m_pkthdr.tx_tcp_e_pid = so->e_pid;
-       else
+       } else {
                 m->m_pkthdr.tx_tcp_e_pid = 0;
                 m->m_pkthdr.tx_tcp_e_pid = 0;
+       }
  
         m->m_nextpkt = NULL;
  
  
         m->m_nextpkt = NULL;
  
@@ -2498,15 +2633,15 @@ timer:
                  * 3. Only ACK flag is set.
                  * 4. there is no outstanding data on this connection.
                  */
                  * 3. Only ACK flag is set.
                  * 4. there is no outstanding data on this connection.
                  */
-               if (tcp_prioritize_acks != 0 && len == 0 &&
-                   (inp->inp_last_outifp->if_eflags &
-                   (IFEF_TXSTART | IFEF_NOACKPRI)) == IFEF_TXSTART) {
+               if (len == 0 && (inp->inp_last_outifp->if_eflags & (IFEF_TXSTART | IFEF_NOACKPRI)) == IFEF_TXSTART) {
                         if (th->th_flags == TH_ACK &&
                             tp->snd_una == tp->snd_max &&
                         if (th->th_flags == TH_ACK &&
                             tp->snd_una == tp->snd_max &&
-                           tp->t_timer[TCPT_REXMT] == 0)
+                           tp->t_timer[TCPT_REXMT] == 0) {
                                 svc_flags |= PKT_SCF_TCP_ACK;
                                 svc_flags |= PKT_SCF_TCP_ACK;
-                       if (th->th_flags & TH_SYN)
+                       }
+                       if (th->th_flags & TH_SYN) {
                                 svc_flags |= PKT_SCF_TCP_SYN;
                                 svc_flags |= PKT_SCF_TCP_SYN;
+                       }
                 }
                 set_packet_service_class(m, so, sotc, svc_flags);
         } else {
                 }
                 set_packet_service_class(m, so, sotc, svc_flags);
         } else {
@@ -2524,16 +2659,13 @@ timer:
         tp->t_pktlist_sentlen += len;
         tp->t_lastchain++;
  
         tp->t_pktlist_sentlen += len;
         tp->t_lastchain++;
  
-#if INET6
         if (isipv6) {
                 DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp,
         if (isipv6) {
                 DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp,
-                       struct ip6 *, ip6, struct tcpcb *, tp, struct tcphdr *,
-                       th);
-       } else
-#endif /* INET6 */
-       {
+                   struct ip6 *, ip6, struct tcpcb *, tp, struct tcphdr *,
+                   th);
+       } else {
                 DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp,
                 DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp,
-                       struct ip *, ip, struct tcpcb *, tp, struct tcphdr *, th);
+                   struct ip *, ip, struct tcpcb *, tp, struct tcphdr *, th);
         }
  
         if (tp->t_pktlist_head != NULL) {
         }
  
         if (tp->t_pktlist_head != NULL) {
@@ -2544,30 +2676,6 @@ timer:
                 tp->t_pktlist_head = tp->t_pktlist_tail = m;
         }
  
                 tp->t_pktlist_head = tp->t_pktlist_tail = m;
         }
  
-       if (lro_ackmore && !sackoptlen && tp->t_timer[TCPT_PERSIST] == 0 &&
-           (th->th_flags & TH_ACK) == TH_ACK && len == 0 &&
-           tp->t_state == TCPS_ESTABLISHED) {
-               /* For a pure ACK, see if you need to send more of them */
-               mnext = tcp_send_lroacks(tp, m, th);
-               if (mnext) {
-                       tp->t_pktlist_tail->m_nextpkt = mnext;
-                       if (mnext->m_nextpkt == NULL) {
-                               tp->t_pktlist_tail = mnext;
-                               tp->t_lastchain++;
-                       } else {
-                               struct mbuf *tail, *next;
-                               next = mnext->m_nextpkt;
-                               tail = next->m_nextpkt;
-                               while (tail) {
-                                       next = tail;
-                                       tail = tail->m_nextpkt;
-                                       tp->t_lastchain++;
-                               }
-                               tp->t_pktlist_tail = next;
-                       }
-               }
-       }
-
         if (sendalot == 0 || (tp->t_state != TCPS_ESTABLISHED) ||
             (tp->snd_cwnd <= (tp->snd_wnd / 8)) ||
             (tp->t_flags & TF_ACKNOW) ||
         if (sendalot == 0 || (tp->t_state != TCPS_ESTABLISHED) ||
             (tp->snd_cwnd <= (tp->snd_wnd / 8)) ||
             (tp->t_flags & TF_ACKNOW) ||
@@ -2575,7 +2683,7 @@ timer:
             tp->t_lastchain >= tcp_packet_chaining) {
                 error = 0;
                 while (inp->inp_sndinprog_cnt == 0 &&
             tp->t_lastchain >= tcp_packet_chaining) {
                 error = 0;
                 while (inp->inp_sndinprog_cnt == 0 &&
-                       tp->t_pktlist_head != NULL) {
+                   tp->t_pktlist_head != NULL) {
                         packetlist = tp->t_pktlist_head;
                         packchain_listadd = tp->t_lastchain;
                         packchain_sent++;
                         packetlist = tp->t_pktlist_head;
                         packchain_listadd = tp->t_lastchain;
                         packchain_sent++;
@@ -2601,7 +2709,7 @@ timer:
                 }
                 /* tcp was closed while we were in ip; resume close */
                 if (inp->inp_sndinprog_cnt == 0 &&
                 }
                 /* tcp was closed while we were in ip; resume close */
                 if (inp->inp_sndinprog_cnt == 0 &&
-                       (tp->t_flags & TF_CLOSING)) {
+                   (tp->t_flags & TF_CLOSING)) {
                         tp->t_flags &= ~TF_CLOSING;
                         (void) tcp_close(tp);
                         return 0;
                         tp->t_flags &= ~TF_CLOSING;
                         (void) tcp_close(tp);
                         return 0;
@@ -2632,23 +2740,36 @@ timer:
                                         if (SEQ_GT((p->rxmit - lost),
                                             tp->snd_una)) {
                                                 p->rxmit -= lost;
                                         if (SEQ_GT((p->rxmit - lost),
                                             tp->snd_una)) {
                                                 p->rxmit -= lost;
+
+                                               if (SEQ_LT(p->rxmit, p->start)) {
+                                                       p->rxmit = p->start;
+                                               }
                                         } else {
                                                 lost = p->rxmit - tp->snd_una;
                                                 p->rxmit = tp->snd_una;
                                         } else {
                                                 lost = p->rxmit - tp->snd_una;
                                                 p->rxmit = tp->snd_una;
+
+                                               if (SEQ_LT(p->rxmit, p->start)) {
+                                                       p->rxmit = p->start;
+                                               }
                                         }
                                         tp->sackhint.sack_bytes_rexmit -= lost;
                                         }
                                         tp->sackhint.sack_bytes_rexmit -= lost;
+                                       if (tp->sackhint.sack_bytes_rexmit < 0) {
+                                               tp->sackhint.sack_bytes_rexmit = 0;
+                                       }
                                 } else {
                                         if (SEQ_GT((tp->snd_nxt - lost),
                                 } else {
                                         if (SEQ_GT((tp->snd_nxt - lost),
-                                               tp->snd_una))
+                                           tp->snd_una)) {
                                                 tp->snd_nxt -= lost;
                                                 tp->snd_nxt -= lost;
-                                       else
+                                       } else {
                                                 tp->snd_nxt = tp->snd_una;
                                                 tp->snd_nxt = tp->snd_una;
+                                       }
                                 }
                         }
                 }
  out:
                                 }
                         }
                 }
  out:
-               if (tp->t_pktlist_head != NULL)
+               if (tp->t_pktlist_head != NULL) {
                         m_freem_list(tp->t_pktlist_head);
                         m_freem_list(tp->t_pktlist_head);
+               }
                 TCP_PKTLIST_CLEAR(tp);
  
                 if (error == ENOBUFS) {
                 TCP_PKTLIST_CLEAR(tp);
  
                 if (error == ENOBUFS) {
@@ -2660,13 +2781,14 @@ out:
                         if (tp->t_timer[TCPT_REXMT] == 0 &&
                             tp->t_timer[TCPT_PERSIST] == 0 &&
                             (len != 0 || (flags & (TH_SYN | TH_FIN)) != 0 ||
                         if (tp->t_timer[TCPT_REXMT] == 0 &&
                             tp->t_timer[TCPT_PERSIST] == 0 &&
                             (len != 0 || (flags & (TH_SYN | TH_FIN)) != 0 ||
-                           so->so_snd.sb_cc > 0))
+                           so->so_snd.sb_cc > 0)) {
                                 tp->t_timer[TCPT_REXMT] =
                                 tp->t_timer[TCPT_REXMT] =
-                                       OFFSET_FROM_START(tp, tp->t_rxtcur);
+                                   OFFSET_FROM_START(tp, tp->t_rxtcur);
+                       }
                         tp->snd_cwnd = tp->t_maxseg;
                         tp->t_bytes_acked = 0;
                         tcp_check_timer_state(tp);
                         tp->snd_cwnd = tp->t_maxseg;
                         tp->t_bytes_acked = 0;
                         tcp_check_timer_state(tp);
-                       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0);
+                       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
  
                         tcp_ccdbg_trace(tp, NULL, TCP_CC_OUTPUT_ERROR);
                         return 0;
  
                         tcp_ccdbg_trace(tp, NULL, TCP_CC_OUTPUT_ERROR);
                         return 0;
@@ -2684,35 +2806,37 @@ out:
                          * immediatly retry with MSS sized segments generated
                          * by this function.
                          */
                          * immediatly retry with MSS sized segments generated
                          * by this function.
                          */
-                       if (tso)
+                       if (tso) {
                                 tp->t_flags &= ~TF_TSO;
                                 tp->t_flags &= ~TF_TSO;
+                       }
  
                         tcp_mtudisc(inp, 0);
                         tcp_check_timer_state(tp);
  
  
                         tcp_mtudisc(inp, 0);
                         tcp_check_timer_state(tp);
  
-                       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0);
+                       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
                         return 0;
                 }
                 /*
                  * Unless this is due to interface restriction policy,
                         return 0;
                 }
                 /*
                  * Unless this is due to interface restriction policy,
-                * treat EHOSTUNREACH/ENETDOWN as a soft error.
+                * treat EHOSTUNREACH/ENETDOWN/EADDRNOTAVAIL as a soft error.
                  */
                  */
-               if ((error == EHOSTUNREACH || error == ENETDOWN) &&
+               if ((error == EHOSTUNREACH || error == ENETDOWN || error == EADDRNOTAVAIL) &&
                     TCPS_HAVERCVDSYN(tp->t_state) &&
                     !inp_restricted_send(inp, inp->inp_last_outifp)) {
                     TCPS_HAVERCVDSYN(tp->t_state) &&
                     !inp_restricted_send(inp, inp->inp_last_outifp)) {
-                               tp->t_softerror = error;
-                               error = 0;
+                       tp->t_softerror = error;
+                       error = 0;
                 }
                 tcp_check_timer_state(tp);
                 }
                 tcp_check_timer_state(tp);
-               KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0);
+               KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
                 return error;
         }
  
         tcpstat.tcps_sndtotal++;
  
                 return error;
         }
  
         tcpstat.tcps_sndtotal++;
  
-       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END,0,0,0,0,0);
-       if (sendalot)
+       KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+       if (sendalot) {
                 goto again;
                 goto again;
+       }
  
         tcp_check_timer_state(tp);
  
  
         tcp_check_timer_state(tp);
  
@@ -2731,13 +2855,13 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
         struct ip_out_args ipoa;
         struct route ro;
         struct ifnet *outif = NULL;
         struct ip_out_args ipoa;
         struct route ro;
         struct ifnet *outif = NULL;
+       bool check_qos_marking_again = (so->so_flags1 & SOF1_QOSMARKING_POLICY_OVERRIDE) ? FALSE : TRUE;
  
         bzero(&ipoa, sizeof(ipoa));
         ipoa.ipoa_boundif = IFSCOPE_NONE;
         ipoa.ipoa_flags = IPOAF_SELECT_SRCIF | IPOAF_BOUND_SRCADDR;
         ipoa.ipoa_sotc = SO_TC_UNSPEC;
         ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
  
         bzero(&ipoa, sizeof(ipoa));
         ipoa.ipoa_boundif = IFSCOPE_NONE;
         ipoa.ipoa_flags = IPOAF_SELECT_SRCIF | IPOAF_BOUND_SRCADDR;
         ipoa.ipoa_sotc = SO_TC_UNSPEC;
         ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
-#if INET6
         struct ip6_out_args ip6oa;
         struct route_in6 ro6;
  
         struct ip6_out_args ip6oa;
         struct route_in6 ro6;
  
@@ -2749,93 +2873,84 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
  
         struct flowadv *adv =
             (isipv6 ? &ip6oa.ip6oa_flowadv : &ipoa.ipoa_flowadv);
  
         struct flowadv *adv =
             (isipv6 ? &ip6oa.ip6oa_flowadv : &ipoa.ipoa_flowadv);
-#else /* INET6 */
-       struct flowadv *adv = &ipoa.ipoa_flowadv;
-#endif /* !INET6 */
  
         /* If socket was bound to an ifindex, tell ip_output about it */
         if (inp->inp_flags & INP_BOUND_IF) {
  
         /* If socket was bound to an ifindex, tell ip_output about it */
         if (inp->inp_flags & INP_BOUND_IF) {
-#if INET6
                 if (isipv6) {
                         ip6oa.ip6oa_boundif = inp->inp_boundifp->if_index;
                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
                 if (isipv6) {
                         ip6oa.ip6oa_boundif = inp->inp_boundifp->if_index;
                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
-               } else
-#endif /* INET6 */
-               {
+               } else {
                         ipoa.ipoa_boundif = inp->inp_boundifp->if_index;
                         ipoa.ipoa_flags |= IPOAF_BOUND_IF;
                 }
         }
  
         if (INP_NO_CELLULAR(inp)) {
                         ipoa.ipoa_boundif = inp->inp_boundifp->if_index;
                         ipoa.ipoa_flags |= IPOAF_BOUND_IF;
                 }
         }
  
         if (INP_NO_CELLULAR(inp)) {
-#if INET6
-               if (isipv6)
+               if (isipv6) {
                         ip6oa.ip6oa_flags |=  IP6OAF_NO_CELLULAR;
                         ip6oa.ip6oa_flags |=  IP6OAF_NO_CELLULAR;
-               else
-#endif /* INET6 */
+               } else {
                         ipoa.ipoa_flags |=  IPOAF_NO_CELLULAR;
                         ipoa.ipoa_flags |=  IPOAF_NO_CELLULAR;
+               }
         }
         if (INP_NO_EXPENSIVE(inp)) {
         }
         if (INP_NO_EXPENSIVE(inp)) {
-#if INET6
-               if (isipv6)
+               if (isipv6) {
                         ip6oa.ip6oa_flags |=  IP6OAF_NO_EXPENSIVE;
                         ip6oa.ip6oa_flags |=  IP6OAF_NO_EXPENSIVE;
-               else
-#endif /* INET6 */
+               } else {
                         ipoa.ipoa_flags |=  IPOAF_NO_EXPENSIVE;
                         ipoa.ipoa_flags |=  IPOAF_NO_EXPENSIVE;
-
+               }
         }
         if (INP_NO_CONSTRAINED(inp)) {
         }
         if (INP_NO_CONSTRAINED(inp)) {
-#if INET6
-               if (isipv6)
+               if (isipv6) {
                         ip6oa.ip6oa_flags |=  IP6OAF_NO_CONSTRAINED;
                         ip6oa.ip6oa_flags |=  IP6OAF_NO_CONSTRAINED;
-               else
-#endif /* INET6 */
+               } else {
                         ipoa.ipoa_flags |=  IPOAF_NO_CONSTRAINED;
                         ipoa.ipoa_flags |=  IPOAF_NO_CONSTRAINED;
+               }
         }
         if (INP_AWDL_UNRESTRICTED(inp)) {
         }
         if (INP_AWDL_UNRESTRICTED(inp)) {
-#if INET6
-               if (isipv6)
+               if (isipv6) {
                         ip6oa.ip6oa_flags |=  IP6OAF_AWDL_UNRESTRICTED;
                         ip6oa.ip6oa_flags |=  IP6OAF_AWDL_UNRESTRICTED;
-               else
-#endif /* INET6 */
+               } else {
                         ipoa.ipoa_flags |=  IPOAF_AWDL_UNRESTRICTED;
                         ipoa.ipoa_flags |=  IPOAF_AWDL_UNRESTRICTED;
-
+               }
         }
         }
-#if INET6
         if (INP_INTCOPROC_ALLOWED(inp) && isipv6) {
                 ip6oa.ip6oa_flags |=  IP6OAF_INTCOPROC_ALLOWED;
         }
         if (isipv6) {
                 ip6oa.ip6oa_sotc = so->so_traffic_class;
                 ip6oa.ip6oa_netsvctype = so->so_netsvctype;
         if (INP_INTCOPROC_ALLOWED(inp) && isipv6) {
                 ip6oa.ip6oa_flags |=  IP6OAF_INTCOPROC_ALLOWED;
         }
         if (isipv6) {
                 ip6oa.ip6oa_sotc = so->so_traffic_class;
                 ip6oa.ip6oa_netsvctype = so->so_netsvctype;
-       } else
-#endif /* INET6 */
-       {
+               ip6oa.qos_marking_gencount = inp->inp_policyresult.results.qos_marking_gencount;
+       } else {
                 ipoa.ipoa_sotc = so->so_traffic_class;
                 ipoa.ipoa_netsvctype = so->so_netsvctype;
                 ipoa.ipoa_sotc = so->so_traffic_class;
                 ipoa.ipoa_netsvctype = so->so_netsvctype;
+               ipoa.qos_marking_gencount = inp->inp_policyresult.results.qos_marking_gencount;
         }
         if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED)) {
         }
         if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED)) {
-#if INET6
-               if (isipv6)
+               if (isipv6) {
                         ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED;
                         ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED;
-               else
-#endif /* INET6 */
+               } else {
                         ipoa.ipoa_flags |= IPOAF_QOSMARKING_ALLOWED;
                         ipoa.ipoa_flags |= IPOAF_QOSMARKING_ALLOWED;
+               }
         }
         }
-#if INET6
-       if (isipv6)
+       if (check_qos_marking_again) {
+               if (isipv6) {
+                       ip6oa.ip6oa_flags |= IP6OAF_REDO_QOSMARKING_POLICY;
+               } else {
+                       ipoa.ipoa_flags |= IPOAF_REDO_QOSMARKING_POLICY;
+               }
+       }
+       if (isipv6) {
                 flags |= IPV6_OUTARGS;
                 flags |= IPV6_OUTARGS;
-       else
-#endif /* INET6 */
+       } else {
                 flags |= IP_OUTARGS;
                 flags |= IP_OUTARGS;
+       }
  
         /* Copy the cached route and take an extra reference */
  
         /* Copy the cached route and take an extra reference */
-#if INET6
-       if (isipv6)
+       if (isipv6) {
                 in6p_route_copyout(inp, &ro6);
                 in6p_route_copyout(inp, &ro6);
-       else
-#endif /* INET6 */
+       } else {
                 inp_route_copyout(inp, &ro);
                 inp_route_copyout(inp, &ro);
+       }
  
         /*
          * Make sure ACK/DELACK conditions are cleared before
  
         /*
          * Make sure ACK/DELACK conditions are cleared before
@@ -2861,7 +2976,6 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
         if (tcp_output_unlocked && !so->so_upcallusecount &&
             (tp->t_state == TCPS_ESTABLISHED) && (sack_in_progress == 0) &&
             !IN_FASTRECOVERY(tp) && !(so->so_flags & SOF_MP_SUBFLOW)) {
         if (tcp_output_unlocked && !so->so_upcallusecount &&
             (tp->t_state == TCPS_ESTABLISHED) && (sack_in_progress == 0) &&
             !IN_FASTRECOVERY(tp) && !(so->so_flags & SOF_MP_SUBFLOW)) {
-
                 unlocked = TRUE;
                 socket_unlock(so, 0);
         }
                 unlocked = TRUE;
                 socket_unlock(so, 0);
         }
@@ -2875,12 +2989,9 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
  
         chain = tcp_packet_chaining > 1
  #if IPSEC
  
         chain = tcp_packet_chaining > 1
  #if IPSEC
-               && ipsec_bypass
-#endif
-#if IPFIREWALL
-               && (fw_enable == 0 || fw_bypass)
+           && ipsec_bypass
  #endif
  #endif
-               ; // I'm important, not extraneous
+       ;         // I'm important, not extraneous
  
         while (pkt != NULL) {
                 struct mbuf *npkt = pkt->m_nextpkt;
  
         while (pkt != NULL) {
                 struct mbuf *npkt = pkt->m_nextpkt;
@@ -2900,14 +3011,12 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
                          */
                         cnt = 0;
                 }
                          */
                         cnt = 0;
                 }
-#if INET6
                 if (isipv6) {
                         error = ip6_output_list(pkt, cnt,
                             inp->in6p_outputopts, &ro6, flags, NULL, NULL,
                             &ip6oa);
                         ifdenied = (ip6oa.ip6oa_retflags & IP6OARF_IFDENIED);
                 } else {
                 if (isipv6) {
                         error = ip6_output_list(pkt, cnt,
                             inp->in6p_outputopts, &ro6, flags, NULL, NULL,
                             &ip6oa);
                         ifdenied = (ip6oa.ip6oa_retflags & IP6OARF_IFDENIED);
                 } else {
-#endif /* INET6 */
                         error = ip_output_list(pkt, cnt, opt, &ro, flags, NULL,
                             &ipoa);
                         ifdenied = (ipoa.ipoa_retflags & IPOARF_IFDENIED);
                         error = ip_output_list(pkt, cnt, opt, &ro, flags, NULL,
                             &ipoa);
                         ifdenied = (ipoa.ipoa_retflags & IPOARF_IFDENIED);
@@ -2919,15 +3028,17 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
                          * the callee had taken care of everything; else
                          * we need to free the rest of the chain ourselves.
                          */
                          * the callee had taken care of everything; else
                          * we need to free the rest of the chain ourselves.
                          */
-                       if (!chain)
+                       if (!chain) {
                                 m_freem_list(npkt);
                                 m_freem_list(npkt);
+                       }
                         break;
                 }
                 pkt = npkt;
         }
  
                         break;
                 }
                 pkt = npkt;
         }
  
-       if (unlocked)
+       if (unlocked) {
                 socket_lock(so, 0);
                 socket_lock(so, 0);
+       }
  
         /*
          * Enter flow controlled state if the connection is established
  
         /*
          * Enter flow controlled state if the connection is established
@@ -2945,10 +3056,11 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
                 int rc;
                 rc = inp_set_fc_state(inp, adv->code);
  
                 int rc;
                 rc = inp_set_fc_state(inp, adv->code);
  
-               if (rc == 1)
+               if (rc == 1) {
                         tcp_ccdbg_trace(tp, NULL,
                             ((adv->code == FADV_FLOW_CONTROLLED) ?
                             TCP_CC_FLOW_CONTROL : TCP_CC_SUSPEND));
                         tcp_ccdbg_trace(tp, NULL,
                             ((adv->code == FADV_FLOW_CONTROLLED) ?
                             TCP_CC_FLOW_CONTROL : TCP_CC_SUSPEND));
+               }
         }
  
         /*
         }
  
         /*
@@ -2956,18 +3068,18 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
          * packets are dropped. Return ENOBUFS, to update the
          * pcb state.
          */
          * packets are dropped. Return ENOBUFS, to update the
          * pcb state.
          */
-       if (adv->code == FADV_SUSPENDED)
+       if (adv->code == FADV_SUSPENDED) {
                 error = ENOBUFS;
                 error = ENOBUFS;
+       }
  
         VERIFY(inp->inp_sndinprog_cnt > 0);
  
         VERIFY(inp->inp_sndinprog_cnt > 0);
-       if ( --inp->inp_sndinprog_cnt == 0) {
+       if (--inp->inp_sndinprog_cnt == 0) {
                 inp->inp_flags &= ~(INP_FC_FEEDBACK);
                 if (inp->inp_sndingprog_waiters > 0) {
                         wakeup(&inp->inp_sndinprog_cnt);
                 }
         }
  
                 inp->inp_flags &= ~(INP_FC_FEEDBACK);
                 if (inp->inp_sndingprog_waiters > 0) {
                         wakeup(&inp->inp_sndinprog_cnt);
                 }
         }
  
-#if INET6
         if (isipv6) {
                 /*
                  * When an NECP IP tunnel policy forces the outbound interface,
         if (isipv6) {
                 /*
                  * When an NECP IP tunnel policy forces the outbound interface,
@@ -2979,10 +3091,28 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
                 } else if (ro6.ro_rt != NULL) {
                         outif = ro6.ro_rt->rt_ifp;
                 }
                 } else if (ro6.ro_rt != NULL) {
                         outif = ro6.ro_rt->rt_ifp;
                 }
-       } else
-#endif /* INET6 */
-               if (ro.ro_rt != NULL)
+       } else {
+               if (ro.ro_rt != NULL) {
                         outif = ro.ro_rt->rt_ifp;
                         outif = ro.ro_rt->rt_ifp;
+               }
+       }
+       if (check_qos_marking_again) {
+               uint32_t qos_marking_gencount;
+               bool allow_qos_marking;
+               if (isipv6) {
+                       qos_marking_gencount = ip6oa.qos_marking_gencount;
+                       allow_qos_marking = ip6oa.ip6oa_flags & IP6OAF_QOSMARKING_ALLOWED ? TRUE : FALSE;
+               } else {
+                       qos_marking_gencount = ipoa.qos_marking_gencount;
+                       allow_qos_marking = ipoa.ipoa_flags & IPOAF_QOSMARKING_ALLOWED ? TRUE : FALSE;
+               }
+               inp->inp_policyresult.results.qos_marking_gencount = qos_marking_gencount;
+               if (allow_qos_marking == TRUE) {
+                       inp->inp_socket->so_flags1 |= SOF1_QOSMARKING_ALLOWED;
+               } else {
+                       inp->inp_socket->so_flags1 &= ~SOF1_QOSMARKING_ALLOWED;
+               }
+       }
  
         if (outif != NULL && outif != inp->inp_last_outifp) {
                 /* Update the send byte count */
  
         if (outif != NULL && outif != inp->inp_last_outifp) {
                 /* Update the send byte count */
@@ -2992,24 +3122,23 @@ tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
                         so->so_snd.sb_flags &= ~SB_SNDBYTE_CNT;
                 }
                 inp->inp_last_outifp = outif;
                         so->so_snd.sb_flags &= ~SB_SNDBYTE_CNT;
                 }
                 inp->inp_last_outifp = outif;
-
         }
  
         if (error != 0 && ifdenied &&
         }
  
         if (error != 0 && ifdenied &&
-           (INP_NO_CELLULAR(inp) || INP_NO_EXPENSIVE(inp) || INP_NO_CONSTRAINED(inp)))
+           (INP_NO_CELLULAR(inp) || INP_NO_EXPENSIVE(inp) || INP_NO_CONSTRAINED(inp))) {
                 soevent(so,
                 soevent(so,
-                   (SO_FILT_HINT_LOCKED|SO_FILT_HINT_IFDENIED));
+                   (SO_FILT_HINT_LOCKED | SO_FILT_HINT_IFDENIED));
+       }
  
         /* Synchronize cached PCB route & options */
  
         /* Synchronize cached PCB route & options */
-#if INET6
-       if (isipv6)
+       if (isipv6) {
                 in6p_route_copyin(inp, &ro6);
                 in6p_route_copyin(inp, &ro6);
-       else
-#endif /* INET6 */
+       } else {
                 inp_route_copyin(inp, &ro);
                 inp_route_copyin(inp, &ro);
+       }
  
         if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift == 0 &&
  
         if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift == 0 &&
-               tp->t_inpcb->inp_route.ro_rt != NULL) {
+           tp->t_inpcb->inp_route.ro_rt != NULL) {
                 /* If we found the route and there is an rtt on it
                  * reset the retransmit timer
                  */
                 /* If we found the route and there is an rtt on it
                  * reset the retransmit timer
                  */
@@ -3046,111 +3175,13 @@ tcp_setpersist(struct tcpcb *tp)
             tcptv_persmin_val, TCPTV_PERSMAX, 0);
         tp->t_timer[TCPT_PERSIST] = OFFSET_FROM_START(tp, tp->t_timer[TCPT_PERSIST]);
  
             tcptv_persmin_val, TCPTV_PERSMAX, 0);
         tp->t_timer[TCPT_PERSIST] = OFFSET_FROM_START(tp, tp->t_timer[TCPT_PERSIST]);
  
-       if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
+       if (tp->t_rxtshift < TCP_MAXRXTSHIFT) {
                 tp->t_rxtshift++;
                 tp->t_rxtshift++;
-}
-
-/*
- * Send as many acks as data coalesced. Every other packet when stretch
- * ACK is not enabled. Every 8 packets, if stretch ACK is enabled.
- */
-static struct mbuf*
-tcp_send_lroacks(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th)
-{
-       struct mbuf *mnext = NULL, *ack_chain = NULL, *tail = NULL;
-       int count = 0;
-       tcp_seq org_ack = ntohl(th->th_ack);
-       tcp_seq prev_ack = 0;
-       int tack_offset = 28; /* IPv6 and IP options not supported */
-       int twin_offset = 34; /* IPv6 and IP options not supported */
-       int ack_size = (tp->t_flags & TF_STRETCHACK) ?
-                       (maxseg_unacked * tp->t_maxseg) : (tp->t_maxseg << 1);
-       int segs_acked = (tp->t_flags & TF_STRETCHACK) ? maxseg_unacked : 2;
-       struct mbuf *prev_ack_pkt = NULL;
-       struct socket *so = tp->t_inpcb->inp_socket;
-       unsigned short winsz = ntohs(th->th_win);
-       unsigned int scaled_win = winsz<<tp->rcv_scale;
-       tcp_seq win_rtedge = org_ack + scaled_win;
-
-       count = tp->t_lropktlen/tp->t_maxseg;
-
-       prev_ack = (org_ack - tp->t_lropktlen) + ack_size;
-       if (prev_ack < org_ack) {
-               ack_chain = m_dup(m, M_DONTWAIT);
-               if (ack_chain) {
-                       th->th_ack = htonl(prev_ack);
-                       /* Keep adv window constant for duplicated ACK packets */
-                       scaled_win = win_rtedge - prev_ack;
-                       if (scaled_win > (int32_t)(TCP_MAXWIN << tp->rcv_scale))
-                               scaled_win = (int32_t)(TCP_MAXWIN << tp->rcv_scale);
-                       th->th_win = htons(scaled_win>>tp->rcv_scale);
-                       if (lrodebug == 5) {
-                               printf("%s: win = %d winsz = %d sc = %d"
-                                   " lro_len %d %d\n",
-                                   __func__, scaled_win>>tp->rcv_scale, winsz,
-                                   tp->rcv_scale, tp->t_lropktlen, count);
-                       }
-                       tail = ack_chain;
-                       count -= segs_acked; /* accounts for prev_ack packet */
-                       count = (count <= segs_acked) ? 0 : count - segs_acked;
-                       tcpstat.tcps_sndacks++;
-                       so_tc_update_stats(m, so, m_get_service_class(m));
-               } else {
-                       return NULL;
-               }
-       }
-       else {
-               tp->t_lropktlen = 0;
-               return NULL;
         }
         }
-
-       prev_ack_pkt = ack_chain;
-
-       while (count > 0) {
-               if ((prev_ack + ack_size) < org_ack) {
-                       prev_ack += ack_size;
-               } else {
-                       /*
-                        * The last ACK sent must have the ACK number that TCP
-                        * thinks is the last sent ACK number.
-                        */
-                        prev_ack = org_ack;
-               }
-               mnext = m_dup(prev_ack_pkt, M_DONTWAIT);
-               if (mnext) {
-                       /* Keep adv window constant for duplicated ACK packets */
-                       scaled_win = win_rtedge - prev_ack;
-                       if (scaled_win > (int32_t)(TCP_MAXWIN << tp->rcv_scale))
-                               scaled_win = (int32_t)(TCP_MAXWIN << tp->rcv_scale);
-                       winsz = htons(scaled_win>>tp->rcv_scale);
-                       if (lrodebug == 5) {
-                               printf("%s: winsz = %d ack %x count %d\n",
-                                   __func__, scaled_win>>tp->rcv_scale,
-                                   prev_ack, count);
-                       }
-                       bcopy(&winsz, mtod(prev_ack_pkt, caddr_t) + twin_offset, 2);
-                       HTONL(prev_ack);
-                       bcopy(&prev_ack, mtod(prev_ack_pkt, caddr_t) + tack_offset, 4);
-                       NTOHL(prev_ack);
-                       tail->m_nextpkt = mnext;
-                       tail = mnext;
-                       count -= segs_acked;
-                       tcpstat.tcps_sndacks++;
-                       so_tc_update_stats(m, so, m_get_service_class(m));
-               } else {
-                       if (lrodebug == 5) {
-                               printf("%s: failed to alloc mbuf.\n", __func__);
-                       }
-                       break;
-               }
-               prev_ack_pkt = mnext;
-       }
-       tp->t_lropktlen = 0;
-       return ack_chain;
  }
  
  static int
  }
  
  static int
-tcp_recv_throttle (struct tcpcb *tp)
+tcp_recv_throttle(struct tcpcb *tp)
  {
         uint32_t base_rtt, newsize;
         struct sockbuf *sbrcv = &tp->t_inpcb->inp_socket->so_rcv;
  {
         uint32_t base_rtt, newsize;
         struct sockbuf *sbrcv = &tp->t_inpcb->inp_socket->so_rcv;
@@ -3166,8 +3197,9 @@ tcp_recv_throttle (struct tcpcb *tp)
                  * If the connection is already being throttled, leave it
                  * in that state until rtt comes closer to base rtt
                  */
                  * If the connection is already being throttled, leave it
                  * in that state until rtt comes closer to base rtt
                  */
-               if (tp->t_flagsext & TF_RECV_THROTTLE)
+               if (tp->t_flagsext & TF_RECV_THROTTLE) {
                         return 1;
                         return 1;
+               }
  
                 base_rtt = get_base_rtt(tp);
  
  
                 base_rtt = get_base_rtt(tp);
  
@@ -3178,8 +3210,9 @@ tcp_recv_throttle (struct tcpcb *tp)
                          */
                         if (tp->t_rttcur > (base_rtt + target_qdelay)) {
                                 tp->t_flagsext |= TF_RECV_THROTTLE;
                          */
                         if (tp->t_rttcur > (base_rtt + target_qdelay)) {
                                 tp->t_flagsext |= TF_RECV_THROTTLE;
-                               if (tp->t_recv_throttle_ts == 0)
+                               if (tp->t_recv_throttle_ts == 0) {
                                         tp->t_recv_throttle_ts = tcp_now;
                                         tp->t_recv_throttle_ts = tcp_now;
+                               }
                                 /*
                                  * Reduce the recv socket buffer size to
                                  * minimize latecy.
                                 /*
                                  * Reduce the recv socket buffer size to
                                  * minimize latecy.
@@ -3204,8 +3237,9 @@ tcp_recv_throttle (struct tcpcb *tp)
          * Timestamps are not supported or there is no good RTT
          * measurement. Use IPDV in this case.
          */
          * Timestamps are not supported or there is no good RTT
          * measurement. Use IPDV in this case.
          */
-       if (tp->acc_iaj > tcp_acc_iaj_react_limit)
+       if (tp->acc_iaj > tcp_acc_iaj_react_limit) {
                 return 1;
                 return 1;
+       }
  
         return 0;
  }
  
         return 0;
  }