xnu-1228.5.20.tar.gz

[apple/xnu.git] / bsd / netinet / tcp_timer.c

diff --git a/bsd/netinet/tcp_timer.c b/bsd/netinet/tcp_timer.c
index 1ce4620ba453bda7b5c92a30bfb9741088bd945e..e8de99b71f73b2e6167fd787d3793c638234f177 100644 (file)
--- a/bsd/netinet/tcp_timer.c
+++ b/bsd/netinet/tcp_timer.c
@@ -1,5 +1,5 @@
 /*
 /*

- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2007 Apple Inc. All rights reserved.

  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 


@@ -94,9 +94,15 @@
 #endif
 #include <sys/kdebug.h>
 
 #endif
 #include <sys/kdebug.h>
 

+extern void postevent(struct socket *, struct sockbuf *,
+                                               int);

 #define DBG_FNC_TCP_FAST       NETDBG_CODE(DBG_NETTCP, (5 << 8))
 #define DBG_FNC_TCP_SLOW       NETDBG_CODE(DBG_NETTCP, (5 << 8) | 1)
 
 #define DBG_FNC_TCP_FAST       NETDBG_CODE(DBG_NETTCP, (5 << 8))
 #define DBG_FNC_TCP_SLOW       NETDBG_CODE(DBG_NETTCP, (5 << 8) | 1)
 

+static int     background_io_trigger = 5;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_io_trigger, CTLFLAG_RW,
+    &background_io_trigger, 0, "Background IO Trigger Setting");
+

 /*
  * NOTE - WARNING
  *
 /*
  * NOTE - WARNING
  *


@@ -107,16 +113,17 @@
 static int
 sysctl_msec_to_ticks SYSCTL_HANDLER_ARGS
 {
 static int
 sysctl_msec_to_ticks SYSCTL_HANDLER_ARGS
 {

+#pragma unused(arg1, arg2)

        int error, s, tt;
 
        tt = *(int *)oidp->oid_arg1;
        int error, s, tt;
 
        tt = *(int *)oidp->oid_arg1;

-       s = tt * 1000 / hz;
+       s = tt * 1000 / TCP_RETRANSHZ;;

 
        error = sysctl_handle_int(oidp, &s, 0, req);
        if (error || !req->newptr)
                return (error);
 
 
        error = sysctl_handle_int(oidp, &s, 0, req);
        if (error || !req->newptr)
                return (error);
 

-       tt = s * hz / 1000;
+       tt = s * TCP_RETRANSHZ / 1000;

        if (tt < 1)
                return (EINVAL);
 
        if (tt < 1)
                return (EINVAL);
 


@@ -136,11 +143,6 @@ int        tcp_keepintvl;
 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW,
     &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "");
 
 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW,
     &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "");
 

-int    tcp_delacktime;
-SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime,
-    CTLTYPE_INT|CTLFLAG_RW, &tcp_delacktime, 0, sysctl_msec_to_ticks, "I",
-    "Time before a delayed ACK is sent");
- 

 int    tcp_msl;
 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW,
     &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");
 int    tcp_msl;
 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW,
     &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");


@@ -150,6 +152,7 @@ SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW,
     &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
 
 static int     tcp_keepcnt = TCPTV_KEEPCNT;
     &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
 
 static int     tcp_keepcnt = TCPTV_KEEPCNT;

+static int     tcp_gc_done = FALSE;    /* perfromed garbage collection of "used" sockets */

        /* max idle probes */
 int    tcp_maxpersistidle;
        /* max idle time in persist */
        /* max idle probes */
 int    tcp_maxpersistidle;
        /* max idle time in persist */


@@ -160,23 +163,34 @@ int               cur_tw_slot = 0;
 
 u_long         *delack_bitmask;
 
 
 u_long         *delack_bitmask;
 

+void   add_to_time_wait_locked(struct tcpcb *tp);
+void   add_to_time_wait(struct tcpcb *tp) ;
+

 
 

-void   add_to_time_wait_locked(tp) 
-       struct tcpcb    *tp;
+void   add_to_time_wait_locked(struct tcpcb *tp) 

 {
        int             tw_slot;
 {
        int             tw_slot;

+    struct inpcbinfo *pcbinfo  = &tcbinfo;

 
        /* pcb list should be locked when we get here */        
 
        /* pcb list should be locked when we get here */        

-#if 0
-       lck_mtx_assert(tp->t_inpcb->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
-#endif
+       lck_rw_assert(pcbinfo->mtx, LCK_RW_ASSERT_EXCLUSIVE);

 
        LIST_REMOVE(tp->t_inpcb, inp_list);
 
 
        LIST_REMOVE(tp->t_inpcb, inp_list);
 

-       if (tp->t_timer[TCPT_2MSL] == 0) 
+       if (tp->t_timer[TCPT_2MSL] <= 0) 

            tp->t_timer[TCPT_2MSL] = 1;
 
            tp->t_timer[TCPT_2MSL] = 1;
 

-       tp->t_rcvtime += tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1);
+       /*
+        * Because we're pulling this pcb out of the main TCP pcb list,
+        * we need to recalculate the TCPT_2MSL timer value for tcp_slowtimo
+        * higher timer granularity.
+        */
+
+       tp->t_timer[TCPT_2MSL] = (tp->t_timer[TCPT_2MSL] / TCP_RETRANSHZ) * PR_SLOWHZ;
+       tp->t_rcvtime = (tp->t_rcvtime / TCP_RETRANSHZ) * PR_SLOWHZ;
+
+       tp->t_rcvtime += tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1); 
+

        tw_slot = (tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1)) + cur_tw_slot; 
        if (tw_slot >= N_TIME_WAIT_SLOTS)
            tw_slot -= N_TIME_WAIT_SLOTS;
        tw_slot = (tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1)) + cur_tw_slot; 
        if (tw_slot >= N_TIME_WAIT_SLOTS)
            tw_slot -= N_TIME_WAIT_SLOTS;


@@ -184,8 +198,7 @@ void        add_to_time_wait_locked(tp)
        LIST_INSERT_HEAD(&time_wait_slots[tw_slot], tp->t_inpcb, inp_list);
 }
 
        LIST_INSERT_HEAD(&time_wait_slots[tw_slot], tp->t_inpcb, inp_list);
 }
 

-void   add_to_time_wait(tp) 
-       struct tcpcb    *tp;
+void   add_to_time_wait(struct tcpcb *tp) 

 {
        struct inpcbinfo *pcbinfo               = &tcbinfo;
        
 {
        struct inpcbinfo *pcbinfo               = &tcbinfo;
        


@@ -207,66 +220,154 @@ void     add_to_time_wait(tp)
 void
 tcp_fasttimo()
 {
 void
 tcp_fasttimo()
 {

-    struct inpcb *inp, *inpnxt;
+    struct inpcb *inp;

     register struct tcpcb *tp;
     register struct tcpcb *tp;

+    struct socket *so;
+#if TCPDEBUG
+    int ostate;
+#endif

 
 
     struct inpcbinfo *pcbinfo  = &tcbinfo;
 
 
 
     struct inpcbinfo *pcbinfo  = &tcbinfo;
 

-    int delack_checked = 0, delack_done = 0;
+    int delack_done = 0;

 
     KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_START, 0,0,0,0,0);
 
 
     KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_START, 0,0,0,0,0);
 

-    if (tcp_delack_enabled == 0) 
-       return;

 
     lck_rw_lock_shared(pcbinfo->mtx);
 
     /* Walk the list of valid tcpcbs and send ACKS on the ones with DELACK bit set */
 
 
     lck_rw_lock_shared(pcbinfo->mtx);
 
     /* Walk the list of valid tcpcbs and send ACKS on the ones with DELACK bit set */
 

-    for (inp = tcb.lh_first; inp != NULL; inp = inpnxt) {
-       inpnxt = inp->inp_list.le_next;
-       /* NOTE: it's OK to check the tp because the pcb can't be removed while we hold pcbinfo->mtx) */
-       if ((tp = (struct tcpcb *)inp->inp_ppcb) && (tp->t_flags & TF_DELACK)) {
-               if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) 
-                       continue;
-               tcp_lock(inp->inp_socket, 1, 0);
-               if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
-                       tcp_unlock(inp->inp_socket, 1, 0);
-                       continue;
-               }
-               if (tp->t_flags & TF_DELACK) {
-                       delack_done++;
-                       tp->t_flags &= ~TF_DELACK;
-                       tp->t_flags |= TF_ACKNOW;
-                       tcpstat.tcps_delack++;
-                       (void) tcp_output(tp);
-               }
-               tcp_unlock(inp->inp_socket, 1, 0);
-       }
+    LIST_FOREACH(inp, &tcb, inp_list) {
+
+       so = inp->inp_socket;
+
+       if (so == &tcbinfo.nat_dummy_socket)
+               continue;
+
+       if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) 
+               continue;
+
+       tcp_lock(so, 1, 0);
+
+       if ((in_pcb_checkstate(inp, WNT_RELEASE,1) == WNT_STOPUSING)  && so->so_usecount == 1) {
+               tcp_unlock(so, 1, 0);
+               continue;
+       }
+
+       tp = intotcpcb(inp);
+
+       if (tp == 0 || tp->t_state == TCPS_LISTEN) {
+               tcp_unlock(so, 1, 0);
+               continue; 
+       }
+
+
+       /* Only run the retransmit timer in that case */
+       if (tp->t_timer[0] && --tp->t_timer[0] == 0) {
+               tp = tcp_timers(tp, 0);
+               if (tp == NULL)
+                       goto tpgone;
+       }
+
+       /* TCP pcb  timers following the tcp_now clock rate */
+
+       tp->t_rcvtime++;
+       tp->t_starttime++;
+       if (tp->t_rtttime)
+               tp->t_rtttime++;        
+
+       /*
+        * Process delayed acks (if enabled) according to PR_FASTHZ, not the retrans timer
+        */
+
+       if (tcp_delack_enabled && (tcp_now % (TCP_RETRANSHZ/PR_FASTHZ)) && tp->t_flags & TF_DELACK) {
+               delack_done++;
+               tp->t_flags &= ~TF_DELACK;
+               tp->t_flags |= TF_ACKNOW;
+               tcpstat.tcps_delack++;
+               tp->t_unacksegs = 0;
+               (void) tcp_output(tp);
+       }
+tpgone:
+       tcp_unlock(so, 1, 0);

     }
     }

-    KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_END, delack_checked, delack_done, tcpstat.tcps_delack,0,0);
+    KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_END, delack_done, 0, tcpstat.tcps_delack,0,0);

     lck_rw_done(pcbinfo->mtx);
     lck_rw_done(pcbinfo->mtx);

+
+    tcp_now++;
+    timeout(tcp_fasttimo, 0, hz/TCP_RETRANSHZ);

 }
 
 }
 

-/*
- * Tcp protocol timeout routine called every 500 ms.
- * Updates the timers in all active tcb's and
- * causes finite state machine actions if timers expire.
- */
+void 
+tcp_garbage_collect(inp, istimewait)
+       struct inpcb *inp;
+       int istimewait;
+{
+       struct socket *so;
+       struct tcpcb *tp;
+
+
+               if (inp->inp_socket == &tcbinfo.nat_dummy_socket)
+                               return;
+
+
+               if (!lck_mtx_try_lock(inp->inpcb_mtx)) /* skip if still in use */
+                       return;
+
+               so = inp->inp_socket;
+               tp = intotcpcb(inp);
+
+               if ((so->so_usecount == 1) && 
+                       (so->so_flags & SOF_OVERFLOW)) {
+                               in_pcbdetach(inp);
+                               so->so_usecount--; 
+                               lck_mtx_unlock(inp->inpcb_mtx);
+                               return;
+               }
+               else {
+                       if (inp->inp_wantcnt != WNT_STOPUSING) {
+                               lck_mtx_unlock(inp->inpcb_mtx);
+                               return;
+                       }
+               }
+
+
+               if (so->so_usecount == 0) 
+                       in_pcbdispose(inp);
+               else {
+                       /* Special case:
+                        * - Check for embryonic socket stuck on listener queue (4023660)
+                        * - overflowed socket dropped from the listening queue
+                        * and dispose of remaining reference
+                        */
+                       if ((so->so_usecount == 1) && 
+                         (((tp->t_state == TCPS_CLOSED) && (so->so_head != NULL) && (so->so_state & SS_INCOMP)) || 
+                               (istimewait && (so->so_flags & SOF_OVERFLOW)))) {
+                                       so->so_usecount--; 
+                                       in_pcbdispose(inp);
+                       } else
+                               lck_mtx_unlock(inp->inpcb_mtx);
+               }
+}
+
+static int bg_cnt = 0;
+#define BG_COUNTER_MAX 3
+

 void
 tcp_slowtimo()
 {
 void
 tcp_slowtimo()
 {

-       struct inpcb *inp, *inpnxt;
+       struct inpcb *inp, *nxt;

        struct tcpcb *tp;
        struct socket *so;
        int i;
 #if TCPDEBUG
        int ostate;
 #endif
        struct tcpcb *tp;
        struct socket *so;
        int i;
 #if TCPDEBUG
        int ostate;
 #endif

-#if KDEBUG
-       static int tws_checked;
-#endif
+
+       static int tws_checked = 0;
+

        struct inpcbinfo *pcbinfo               = &tcbinfo;
 
        KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0,0,0,0,0);
        struct inpcbinfo *pcbinfo               = &tcbinfo;
 
        KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0,0,0,0,0);


@@ -275,18 +376,16 @@ tcp_slowtimo()
 
        lck_rw_lock_shared(pcbinfo->mtx);
 
 
        lck_rw_lock_shared(pcbinfo->mtx);
 

-       /*
-        * Search through tcb's and update active timers.
-        */
-       for (inp = tcb.lh_first; inp != NULL; inp = inpnxt) {
-               inpnxt = inp->inp_list.le_next;
+       bg_cnt++;

 
 

-               so = inp->inp_socket;
+       LIST_FOREACH(inp, &tcb, inp_list) {

 
 

+               so = inp->inp_socket;
+       

                if (so == &tcbinfo.nat_dummy_socket)
                if (so == &tcbinfo.nat_dummy_socket)

-                               continue;
+                       continue;

 
 

-               if (in_pcb_checkstate(inp, WNT_ACQUIRE,0) == WNT_STOPUSING) 
+               if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) 

                        continue;
 
                tcp_lock(so, 1, 0);
                        continue;
 
                tcp_lock(so, 1, 0);


@@ -301,44 +400,109 @@ tcp_slowtimo()
                        continue; 
                }
 
                        continue; 
                }
 

-               for (i = 0; i < TCPT_NTIMERS; i++) {
-                       if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
+               tp = intotcpcb(inp);
+
+               if (tp == 0 || tp->t_state == TCPS_LISTEN) 
+                       goto tpgone;
+
+#if TRAFFIC_MGT
+               if (so->so_traffic_mgt_flags & TRAFFIC_MGT_SO_BACKGROUND && 
+                       bg_cnt > BG_COUNTER_MAX) {
+                       u_int32_t       curr_recvtotal = tcpstat.tcps_rcvtotal;
+                       u_int32_t       curr_bg_recvtotal = tcpstat.tcps_bg_rcvtotal;
+                       u_int32_t       bg_recvdiff = curr_bg_recvtotal - tp->bg_recv_snapshot;
+                       u_int32_t       tot_recvdiff = curr_recvtotal - tp->tot_recv_snapshot;
+                       u_int32_t       fg_recv_change = tot_recvdiff - bg_recvdiff;
+                       u_int32_t       recv_change;
+                       
+                       if (!(so->so_traffic_mgt_flags & TRAFFIC_MGT_SO_BG_SUPPRESSED)) {
+                               if (tot_recvdiff) 
+                                       recv_change = (fg_recv_change * 100) / tot_recvdiff;
+                               else 
+                                       recv_change = 0;
+
+                               if (recv_change > background_io_trigger) {
+                                       so->so_traffic_mgt_flags |= TRAFFIC_MGT_SO_BG_SUPPRESSED;
+                               }
+                               
+                               tp->tot_recv_snapshot = curr_recvtotal;
+                               tp->bg_recv_snapshot = curr_bg_recvtotal;
+                       }
+                       else {  // SUPPRESSED
+                               // this allows for bg traffic to subside before we start measuring total traffic change
+                               if (tot_recvdiff)
+                                       recv_change = (bg_recvdiff * 100) / tot_recvdiff;
+                               else
+                                       recv_change = 0;
+                                       
+                               if (recv_change < background_io_trigger) {
+                                       // Draconian for now: if there is any change at all, keep suppressed
+                                       if (!tot_recvdiff) {
+                                               so->so_traffic_mgt_flags &= ~TRAFFIC_MGT_SO_BG_SUPPRESSED;
+                                               tp->t_unacksegs = 0;
+                                               (void) tcp_output(tp);  // open window
+                                       }
+                               }
+
+                               tp->tot_recv_snapshot = curr_recvtotal;
+                               tp->bg_recv_snapshot = curr_bg_recvtotal;
+                       }
+               }
+#endif /* TRAFFIC_MGT */
+
+               for (i = 1; i < TCPT_NTIMERS; i++) {
+                       if (tp->t_timer[i] != 0) {
+                               tp->t_timer[i] -= TCP_RETRANSHZ/PR_SLOWHZ;
+                               if (tp->t_timer[i] <=  0) {

 #if TCPDEBUG
 #if TCPDEBUG

-                               ostate = tp->t_state;
+                                       ostate = tp->t_state;

 #endif
 #endif

-                               tp = tcp_timers(tp, i);
-                               if (tp == NULL)
-                                       goto tpgone;
+
+                                       tp->t_timer[i] = 0; /* account for granularity change between tcp_now and slowtimo */
+                                       tp = tcp_timers(tp, i);
+                                       if (tp == NULL)
+                                               goto tpgone;

 #if TCPDEBUG
 #if TCPDEBUG

-                               if (tp->t_inpcb->inp_socket->so_options
-                                   & SO_DEBUG)
-                                       tcp_trace(TA_USER, ostate, tp,
-                                                 (void *)0,
-                                                 (struct tcphdr *)0,
-                                                 PRU_SLOWTIMO);
+                                       if (tp->t_inpcb->inp_socket->so_options
+                                           & SO_DEBUG)
+                                               tcp_trace(TA_USER, ostate, tp,
+                                                         (void *)0,
+                                                         (struct tcphdr *)0,
+                                                         PRU_SLOWTIMO);

 #endif
 #endif

+                               }

                        }
                }
                        }
                }

-               tp->t_rcvtime++;
-               tp->t_starttime++;
-               if (tp->t_rtttime)
-                       tp->t_rtttime++;        

 tpgone:
                tcp_unlock(so, 1, 0);
        }
 tpgone:
                tcp_unlock(so, 1, 0);
        }

+       
+       if (bg_cnt > 3) 
+               bg_cnt = 0;

 
 

-#if KDEBUG
-       tws_checked = 0;
-#endif
-       KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_NONE, tws_checked,0,0,0,0);
+       /* Second part of tcp_slowtimo: garbage collect socket/tcpcb
+        * We need to acquire the list lock exclusively to do this
+        */
+
+       if (lck_rw_lock_shared_to_exclusive(pcbinfo->mtx) == FALSE) {
+               if (tcp_gc_done == TRUE) {      /* don't sweat it this time. cleanup was done last time */
+                       tcp_gc_done = FALSE;
+                       KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked, cur_tw_slot,0,0,0);
+                       return; /* Upgrade failed and lost lock - give up this time. */
+               }
+               lck_rw_lock_exclusive(pcbinfo->mtx);    /* Upgrade failed, lost lock now take it again exclusive */
+       }
+       tcp_gc_done = TRUE;

 
        /*
         * Process the items in the current time-wait slot
         */
 
        /*
         * Process the items in the current time-wait slot
         */

+#if  KDEBUG
+       tws_checked = 0;
+#endif
+       KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_NONE, tws_checked,0,0,0,0);

 
 

-       for (inp = time_wait_slots[cur_tw_slot].lh_first; inp; inp = inpnxt)
-       {
-               inpnxt = inp->inp_list.le_next;
+       LIST_FOREACH(inp, &time_wait_slots[cur_tw_slot], inp_list) {

 #if KDEBUG
                tws_checked++;
 #endif
 #if KDEBUG
                tws_checked++;
 #endif


@@ -352,12 +516,9 @@ tpgone:
                        goto twunlock;
 
                tp = intotcpcb(inp);
                        goto twunlock;
 
                tp = intotcpcb(inp);

-               if (tp == NULL) { /* tp already closed, remove from list */
-#if TEMPDEBUG
-                       printf("tcp_slowtimo: tp is null in time-wait slot!\n");
-#endif
+               if (tp == NULL)  /* tp already closed, remove from list */

                        goto twunlock;
                        goto twunlock;

-               }
+

                if (tp->t_timer[TCPT_2MSL] >= N_TIME_WAIT_SLOTS) {
                    tp->t_timer[TCPT_2MSL] -= N_TIME_WAIT_SLOTS;
                    tp->t_rcvtime += N_TIME_WAIT_SLOTS;
                if (tp->t_timer[TCPT_2MSL] >= N_TIME_WAIT_SLOTS) {
                    tp->t_timer[TCPT_2MSL] -= N_TIME_WAIT_SLOTS;
                    tp->t_rcvtime += N_TIME_WAIT_SLOTS;


@@ -365,73 +526,26 @@ tpgone:
                else
                    tp->t_timer[TCPT_2MSL] = 0;
 
                else
                    tp->t_timer[TCPT_2MSL] = 0;
 

-               if (tp->t_timer[TCPT_2MSL] == 0)  
-                   tp = tcp_timers(tp, TCPT_2MSL);     /* tp can be returned null if tcp_close is called */
+               if (tp->t_timer[TCPT_2MSL] == 0)  {
+
+                       /* That pcb is ready for a close */     
+                       tcp_free_sackholes(tp);
+                       tp = tcp_close(tp);
+               }

 twunlock:
                tcp_unlock(inp->inp_socket, 1, 0);
        }
 
 twunlock:
                tcp_unlock(inp->inp_socket, 1, 0);
        }
 

-       if (lck_rw_lock_shared_to_exclusive(pcbinfo->mtx) != 0)
-               lck_rw_lock_exclusive(pcbinfo->mtx);    /* Upgrade failed, lost lock no take it again exclusive */
-
-
-       for (inp = tcb.lh_first; inp != NULL; inp = inpnxt) {
-               inpnxt = inp->inp_list.le_next;
-               /* Ignore nat/SharedIP dummy pcbs */
-               if (inp->inp_socket == &tcbinfo.nat_dummy_socket)
-                               continue;
-
-               if (inp->inp_wantcnt != WNT_STOPUSING) 
-                       continue;

 
 

-               so = inp->inp_socket;
-               if (!lck_mtx_try_lock(inp->inpcb_mtx)) {/* skip if in use */
-#if TEMPDEBUG
-                       printf("tcp_slowtimo so=%x STOPUSING but locked...\n", so);
-#endif
-                       continue;
-               }
-
-               if (so->so_usecount == 0) 
-                       in_pcbdispose(inp);
-               else {
-                       tp = intotcpcb(inp);
-                       /* Check for embryonic socket stuck on listener queue (4023660) */
-                       if ((so->so_usecount == 1) && (tp->t_state == TCPS_CLOSED) &&
-                           (so->so_head != NULL) && (so->so_state & SS_INCOMP)) {
-                               so->so_usecount--; 
-                               in_pcbdispose(inp);
-                       } else
-                               lck_mtx_unlock(inp->inpcb_mtx);
-               }
+       LIST_FOREACH_SAFE(inp, &tcb, inp_list, nxt) {
+               tcp_garbage_collect(inp, 0);

        }
 
        /* Now cleanup the time wait ones */
        }
 
        /* Now cleanup the time wait ones */

-       for (inp = time_wait_slots[cur_tw_slot].lh_first; inp; inp = inpnxt)
-       {
-               inpnxt = inp->inp_list.le_next;
-
-               if (inp->inp_wantcnt != WNT_STOPUSING) 
-                       continue;
-
-               so = inp->inp_socket;
-               if (!lck_mtx_try_lock(inp->inpcb_mtx)) /* skip if in use */
-                       continue;
-               if (so->so_usecount == 0)  
-                       in_pcbdispose(inp);
-               else  {
-                       tp = intotcpcb(inp);
-                       /* Check for embryonic socket stuck on listener queue (4023660) */
-                       if ((so->so_usecount == 1) && (tp->t_state == TCPS_CLOSED) &&
-                           (so->so_head != NULL) && (so->so_state & SS_INCOMP)) {
-                               so->so_usecount--; 
-                               in_pcbdispose(inp);
-                       } else
-                               lck_mtx_unlock(inp->inpcb_mtx);
-               }
+       LIST_FOREACH_SAFE(inp, &time_wait_slots[cur_tw_slot], inp_list, nxt) {
+               tcp_garbage_collect(inp, 1);

        }
 
        }
 

-       tcp_now++;

        if (++cur_tw_slot >= N_TIME_WAIT_SLOTS)
                cur_tw_slot = 0;
        
        if (++cur_tw_slot >= N_TIME_WAIT_SLOTS)
                cur_tw_slot = 0;
        


@@ -470,6 +584,7 @@ tcp_timers(tp, timer)
 {
        register int rexmt;
        struct socket *so_tmp;
 {
        register int rexmt;
        struct socket *so_tmp;

+       struct inpcbinfo *pcbinfo               = &tcbinfo;

        struct tcptemp *t_template;
 
 #if TCPDEBUG
        struct tcptemp *t_template;
 
 #if TCPDEBUG


@@ -487,15 +602,17 @@ tcp_timers(tp, timer)
        /*
         * 2 MSL timeout in shutdown went off.  If we're closed but
         * still waiting for peer to close and connection has been idle
        /*
         * 2 MSL timeout in shutdown went off.  If we're closed but
         * still waiting for peer to close and connection has been idle

-        * too long, or if 2MSL time is up from TIME_WAIT, delete connection
-        * control block.  Otherwise, check again in a bit.
+        * too long, or if 2MSL time is up from TIME_WAIT or FIN_WAIT_2,
+        * delete connection control block.
+        * Otherwise, (this case shouldn't happen) check again in a bit
+        * we keep the socket in the main list in that case.

         */
        case TCPT_2MSL:
                tcp_free_sackholes(tp);
                if (tp->t_state != TCPS_TIME_WAIT &&
         */
        case TCPT_2MSL:
                tcp_free_sackholes(tp);
                if (tp->t_state != TCPS_TIME_WAIT &&

-                   tp->t_rcvtime <= tcp_maxidle) {
+                   tp->t_state != TCPS_FIN_WAIT_2 &&
+                   tp->t_rcvtime < tcp_maxidle) {

                        tp->t_timer[TCPT_2MSL] = (unsigned long)tcp_keepintvl;
                        tp->t_timer[TCPT_2MSL] = (unsigned long)tcp_keepintvl;

-                       add_to_time_wait_locked(tp);

                }
                else {
                        tp = tcp_close(tp);
                }
                else {
                        tp = tcp_close(tp);


@@ -536,7 +653,7 @@ tcp_timers(tp, timer)
                                  tp->t_flags |= TF_WASFRECOVERY;
                        else
                                  tp->t_flags &= ~TF_WASFRECOVERY;
                                  tp->t_flags |= TF_WASFRECOVERY;
                        else
                                  tp->t_flags &= ~TF_WASFRECOVERY;

-                       tp->t_badrxtwin = tcp_now + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
+                       tp->t_badrxtwin = tcp_now  + (tp->t_srtt >> (TCP_RTT_SHIFT)); 

                }
                tcpstat.tcps_rexmttimeo++;
                if (tp->t_state == TCPS_SYN_SENT)
                }
                tcpstat.tcps_rexmttimeo++;
                if (tp->t_state == TCPS_SYN_SENT)


@@ -612,13 +729,15 @@ tcp_timers(tp, timer)
                 * growth is 2 mss.  We don't allow the threshhold
                 * to go below this.)
                 */
                 * growth is 2 mss.  We don't allow the threshhold
                 * to go below this.)
                 */

-               {
-               u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
-               if (win < 2)
-                       win = 2;
-               tp->snd_cwnd = tp->t_maxseg;
-               tp->snd_ssthresh = win * tp->t_maxseg;
-               tp->t_dupacks = 0;
+               if (tp->t_state >=  TCPS_ESTABLISHED) {
+                       u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
+                       if (win < 2)
+                               win = 2;
+                       tp->snd_cwnd = tp->t_maxseg;
+                       tp->snd_ssthresh = win * tp->t_maxseg;
+                       tp->t_bytes_acked = 0;
+                       tp->t_dupacks = 0;
+                       tp->t_unacksegs = 0;

                }
                EXIT_FASTRECOVERY(tp);
                (void) tcp_output(tp);
                }
                EXIT_FASTRECOVERY(tp);
                (void) tcp_output(tp);


@@ -648,6 +767,7 @@ tcp_timers(tp, timer)
                }
                tcp_setpersist(tp);
                tp->t_force = 1;
                }
                tcp_setpersist(tp);
                tp->t_force = 1;

+               tp->t_unacksegs = 0;

                (void) tcp_output(tp);
                tp->t_force = 0;
                break;
                (void) tcp_output(tp);
                tp->t_force = 0;
                break;


@@ -662,7 +782,7 @@ tcp_timers(tp, timer)
                        goto dropit;
                if ((always_keepalive ||
                    tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) &&
                        goto dropit;
                if ((always_keepalive ||
                    tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) &&

-                   tp->t_state <= TCPS_CLOSING || tp->t_state == TCPS_FIN_WAIT_2) {
+                   (tp->t_state <= TCPS_CLOSING || tp->t_state == TCPS_FIN_WAIT_2)) {

                        if (tp->t_rcvtime >= TCP_KEEPIDLE(tp) + (unsigned long)tcp_maxidle)
                                goto dropit;
                        /*
                        if (tp->t_rcvtime >= TCP_KEEPIDLE(tp) + (unsigned long)tcp_maxidle)
                                goto dropit;
                        /*


@@ -682,7 +802,7 @@ tcp_timers(tp, timer)
                        if (t_template) {
                                tcp_respond(tp, t_template->tt_ipgen,
                                    &t_template->tt_t, (struct mbuf *)NULL,
                        if (t_template) {
                                tcp_respond(tp, t_template->tt_ipgen,
                                    &t_template->tt_t, (struct mbuf *)NULL,

-                                   tp->rcv_nxt, tp->snd_una - 1, 0);
+                                   tp->rcv_nxt, tp->snd_una - 1, 0, NULL);

                                (void) m_free(dtom(t_template));
                        }
                        tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
                                (void) m_free(dtom(t_template));
                        }
                        tp->t_timer[TCPT_KEEP] = tcp_keepintvl;