Merged in masayuki2009/nuttx.nuttx/fix_tcp_active_close (pull request #923)

net/inet: Fix tcp active close in inet_close.c

In previous implementation, FIN packet was not sent when a socket
is actively closed (e.g. telnetd or webserver) without SO_LINGER.
This issue happens because the socket closing sequence waits for
the status.cl_sem only if lingering timeout is set. However,
in many server use-cases, SO_LINGER is not usually set and even
in these cases, FIN packet must be sent correctly.

This PR changes the logic in inet_close.c so that it can wait
for status.cl_sem regardless of SO_LINGER. Instead, if SO_LINGER
is set, it waits for the semaphore with timeout option.

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

Approved-by: Gregory Nutt <gnutt@nuttx.org>

net/inet/inet_close.c

@@ -78,10 +78,10 @@
 struct tcp_close_s
 {
   FAR struct devif_callback_s *cl_cb;     /* Reference to TCP callback instance */
-#ifdef CONFIG_NET_SOLINGER
   FAR struct socket           *cl_psock;  /* Reference to the TCP socket */
   sem_t                        cl_sem;    /* Signals disconnect completion */
   int                          cl_result; /* The result of the close */
+#ifdef CONFIG_NET_SOLINGER
   clock_t                      cl_start;  /* Time close started (in ticks) */
 #endif
 };
@@ -158,9 +158,7 @@ static uint16_t tcp_close_eventhandler(FAR struct net_driver_s *dev,
                                        FAR void *pvconn, FAR void *pvpriv,
                                        uint16_t flags)
 {
-#ifdef CONFIG_NET_SOLINGER
   FAR struct tcp_close_s *pstate = (FAR struct tcp_close_s *)pvpriv;
-#endif
   FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
 
   DEBUGASSERT(conn != NULL);
@@ -178,7 +176,6 @@ static uint16_t tcp_close_eventhandler(FAR struct net_driver_s *dev,
     {
       /* The disconnection is complete */
 
-#ifdef CONFIG_NET_SOLINGER
       /* pstate non-NULL means that we are performing a LINGERing close. */
 
       if (pstate != NULL)
@@ -194,7 +191,6 @@ static uint16_t tcp_close_eventhandler(FAR struct net_driver_s *dev,
        */
 
       else
-#endif
         {
           /* Free connection resources */
 
@@ -247,7 +243,6 @@ static uint16_t tcp_close_eventhandler(FAR struct net_driver_s *dev,
 
   return flags;
 
-#ifdef CONFIG_NET_SOLINGER
 end_wait:
   pstate->cl_cb->flags = 0;
   pstate->cl_cb->priv  = NULL;
@@ -256,7 +251,6 @@ end_wait:
 
   ninfo("Resuming\n");
   return 0;
-#endif
 }
 #endif /* NET_TCP_HAVE_STACK */
 
@@ -332,7 +326,7 @@ static inline int tcp_close_disconnect(FAR struct socket *psock)
   struct tcp_close_s state;
   FAR struct tcp_conn_s *conn;
 #ifdef CONFIG_NET_SOLINGER
-  bool linger;
+  struct timespec abstime;
 #endif
   int ret = OK;
 
@@ -375,15 +369,6 @@ static inline int tcp_close_disconnect(FAR struct socket *psock)
       state.cl_cb->flags = (TCP_NEWDATA | TCP_POLL | TCP_DISCONN_EVENTS);
       state.cl_cb->event = tcp_close_eventhandler;
 
-#ifdef CONFIG_NET_SOLINGER
-      /* Check for a lingering close */
-
-      linger = _SO_GETOPT(psock->s_options, SO_LINGER);
-
-      /* Has a lingering close been requested */
-
-      if (linger)
-        {
       /* A non-NULL value of the priv field means that lingering is
        * enabled.
        */
@@ -402,56 +387,54 @@ static inline int tcp_close_disconnect(FAR struct socket *psock)
       nxsem_init(&state.cl_sem, 0, 0);
       nxsem_setprotocol(&state.cl_sem, SEM_PRIO_NONE);
 
+#ifdef CONFIG_NET_SOLINGER
       /* Record the time that we started the wait (in ticks) */
 
       state.cl_start = clock_systimer();
-        }
+#endif
-      else
-#endif /* CONFIG_NET_SOLINGER */
-
-        {
-          /* We will close immediately. The NULL priv field signals this */
-
-          state.cl_cb->priv  = NULL;
-
-          /* No further references on the connection */
-
-          conn->crefs = 0;
-        }
 
       /* Notify the device driver of the availability of TX data */
 
       tcp_close_txnotify(psock, conn);
 
-#ifdef CONFIG_NET_SOLINGER
-      /* Wait only if we are lingering */
-
-      if (linger)
-        {
       /* Wait for the disconnect event */
 
-          (void)net_lockedwait(&state.cl_sem);
+#ifdef CONFIG_NET_SOLINGER
+      DEBUGVERIFY(clock_gettime(CLOCK_REALTIME, &abstime));
+
+      /* NOTE: s_linger's unit is deciseconds,
+       * so we don't need to update abstime.tv_nsec here.
+       */
+
+      abstime.tv_sec += psock->s_linger / DSEC_PER_SEC;
+
+      if (-ETIMEDOUT == net_timedwait(&state.cl_sem, &abstime))
+        {
+          state.cl_result = -ETIMEDOUT;
+        }
+#else
+      (void)net_timedwait(&state.cl_sem, NULL);
+#endif
 
       /* We are now disconnected */
 
       nxsem_destroy(&state.cl_sem);
       tcp_callback_free(conn, state.cl_cb);
 
-          /* Free the connection */
+      /* Free the connection
+       * No more references on the connection
+       */
 
-          conn->crefs = 0;          /* No more references on the connection */
+      conn->crefs = 0;
-          tcp_free(conn);           /* Free network resources */
 
       /* Get the result of the close */
 
       ret = state.cl_result;
     }
-#endif /* CONFIG_NET_SOLINGER */
+
-    }
+  /* Free network resources */
-  else
+
-    {
   tcp_free(conn);
-    }
 
   net_unlock();
   return ret;