Centralize TCP loss-of-connection bit twiddling

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5542 42af7a65-404d-4744-a932-0658087f49c3

5 files changed, 120 insertions, 92 deletions

diff --git a/apps/netutils/telnetd/telnetd_driver.c b/apps/netutils/telnetd/telnetd_driver.c
index 274fde370..1b04bfbe5 100644
--- a/apps/netutils/telnetd/telnetd_driver.c
+++ b/apps/netutils/telnetd/telnetd_driver.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/netutils/telnetd_driver.c
  *
- *   Copyright (C) 2007, 2009, 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2009, 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * This is a leverage of similar logic from uIP which has a compatible BSD
@@ -593,6 +593,13 @@ static ssize_t telnetd_read(FAR struct file *filep, FAR char *buffer, size_t len
     }
   while (ret == 0);
 
+  /* Return:
+   *
+   * ret > 0:  The number of characters copied into the user buffer by
+   *           telnetd_receive().
+   * ret <= 0: Loss of connection or error events reported by recv().
+   */
+
   return ret;
 }
 
diff --git a/nuttx/net/net_internal.h b/nuttx/net/net_internal.h
index ed2f12aa7..0726c7a80 100644
--- a/nuttx/net/net_internal.h
+++ b/nuttx/net/net_internal.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * net/net_internal.h
  *
- *   Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -139,94 +139,96 @@
  * Public Variables
  ****************************************************************************/
 
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
 /* List of registered ethernet device drivers */
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
-extern struct uip_driver_s *g_netdevices;
+EXTERN struct uip_driver_s *g_netdevices;
 #endif
 
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/
 
-#undef EXTERN
-#if defined(__cplusplus)
-#define EXTERN extern "C"
-extern "C" {
-#else
-#define EXTERN extern
-#endif
-
 /* net_sockets.c *************************************************************/
 
-EXTERN int  sockfd_allocate(int minsd);
-EXTERN void sock_release(FAR struct socket *psock);
-EXTERN void sockfd_release(int sockfd);
-EXTERN FAR struct socket *sockfd_socket(int sockfd);
+int  sockfd_allocate(int minsd);
+void sock_release(FAR struct socket *psock);
+void sockfd_release(int sockfd);
+FAR struct socket *sockfd_socket(int sockfd);
 
 /* net_connect.c *************************************************************/
 
 #ifdef CONFIG_NET_TCP
-EXTERN int net_startmonitor(FAR struct socket *psock);
-EXTERN void net_stopmonitor(FAR struct uip_conn *conn);
+int net_startmonitor(FAR struct socket *psock);
+void net_stopmonitor(FAR struct uip_conn *conn);
+void net_lostconnection(FAR struct socket *psock, uint16_t flags);
 #endif
 
 /* net_close.c ***************************************************************/
 
-EXTERN int psock_close(FAR struct socket *psock);
+int psock_close(FAR struct socket *psock);
 
 /* sockopt support ***********************************************************/
 
 #if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
-EXTERN int net_timeo(uint32_t start_time, socktimeo_t timeo);
-EXTERN socktimeo_t net_timeval2dsec(struct timeval *tv);
-EXTERN void net_dsec2timeval(uint16_t dsec, struct timeval *tv);
+int net_timeo(uint32_t start_time, socktimeo_t timeo);
+socktimeo_t net_timeval2dsec(FAR struct timeval *tv);
+void net_dsec2timeval(uint16_t dsec, FAR struct timeval *tv);
 #endif
 
 /* net_register.c ************************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
-EXTERN void netdev_seminit(void);
-EXTERN void netdev_semtake(void);
-EXTERN void netdev_semgive(void);
+void netdev_seminit(void);
+void netdev_semtake(void);
+void netdev_semgive(void);
 #endif
 
 /* net_findbyname.c **********************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
-EXTERN FAR struct uip_driver_s *netdev_findbyname(const char *ifname);
+FAR struct uip_driver_s *netdev_findbyname(FAR const char *ifname);
 #endif
 
 /* net_findbyaddr.c **********************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
-EXTERN FAR struct uip_driver_s *netdev_findbyaddr(const uip_ipaddr_t *raddr);
+FAR struct uip_driver_s *netdev_findbyaddr(FAR const uip_ipaddr_t *raddr);
 #endif
 
 /* net_txnotify.c ************************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
-EXTERN void netdev_txnotify(const uip_ipaddr_t *raddr);
+void netdev_txnotify(const uip_ipaddr_t *raddr);
 #endif
 
 /* net_count.c ***************************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
-EXTERN int netdev_count(void);
+int netdev_count(void);
 #endif
 
 /* net_arptimer.c ************************************************************/
 
 #ifdef CONFIG_NET_ARP
-EXTERN void arptimer_init(void);
+void arptimer_init(void);
 #else
 # define arptimer_init()
 #endif
 
 /* send.c ********************************************************************/
 
-EXTERN ssize_t psock_send(FAR struct socket *psock, const void *buf,
-                          size_t len, int flags);
+ssize_t psock_send(FAR struct socket *psock, FAR const void *buf, size_t len,
+                   int flags);
 
 #undef EXTERN
 #if defined(__cplusplus)
diff --git a/nuttx/net/net_monitor.c b/nuttx/net/net_monitor.c
index 4bdae4ccf..1eeb4bd27 100644
--- a/nuttx/net/net_monitor.c
+++ b/nuttx/net/net_monitor.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * net/net_monitor.c
  *
- *   Copyright (C) 2007-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -67,7 +67,6 @@ static void connection_event(struct uip_conn *conn, uint16_t flags);
  *   Some connection related event has occurred
  *
  * Parameters:
- *   dev      The sructure of the network driver that caused the interrupt
  *   conn     The connection structure associated with the socket
  *   flags    Set of events describing why the callback was invoked
  *
@@ -79,7 +78,7 @@ static void connection_event(struct uip_conn *conn, uint16_t flags);
  *
  ****************************************************************************/
 
-static void connection_event(struct uip_conn *conn, uint16_t flags)
+static void connection_event(FAR struct uip_conn *conn, uint16_t flags)
 {
   FAR struct socket *psock = (FAR struct socket *)conn->connection_private;
 
@@ -87,37 +86,11 @@ static void connection_event(struct uip_conn *conn, uint16_t flags)
     {
       nllvdbg("flags: %04x s_flags: %02x\n", flags, psock->s_flags);
 
-      /* These loss-of-connection events may be reported:
-       *
-       *   UIP_CLOSE: The remote host has closed the connection
-       *   UIP_ABORT: The remote host has aborted the connection
-       *   UIP_TIMEDOUT: Connection aborted due to too many retransmissions.
-       *
-       * And we need to set these two socket status bits appropriately:
-       *
-       *  _SF_CONNECTED==1 && _SF_CLOSED==0 - the socket is connected
-       *  _SF_CONNECTED==0 && _SF_CLOSED==1 - the socket was gracefully disconnected
-       *  _SF_CONNECTED==0 && _SF_CLOSED==0 - the socket was rudely disconnected
-       */
+      /* UIP_CLOSE, UIP_ABORT, or UIP_TIMEDOUT: Loss-of-connection events */
 
-      if ((flags & UIP_CLOSE) != 0)
-        {
-          /* The peer gracefully closed the connection.  Marking the
-           * connection as disconnected will suppress some subsequent
-           * ENOTCONN errors from receive.  A graceful disconnection is
-           * not handle as an error but as an "end-of-file"
-           */
-
-          psock->s_flags &= ~_SF_CONNECTED;
-          psock->s_flags |= _SF_CLOSED;
-        }
-      else if ((flags & (UIP_ABORT|UIP_TIMEDOUT)) != 0)
+      if ((flags & (UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT)) != 0)
         {
-          /* The loss of connection was less than graceful.  This will (eventually)
-           * be reported as an ENOTCONN error.
-           */
-
-          psock->s_flags &= ~(_SF_CONNECTED |_SF_CLOSED);
+          net_lostconnection(psock, flags);
         }
 
       /* UIP_CONNECTED: The socket is successfully connected */
@@ -184,4 +157,60 @@ void net_stopmonitor(FAR struct uip_conn *conn)
   conn->connection_event   = NULL;
 }
 
+/****************************************************************************
+ * Name: net_lostconnection
+ *
+ * Description:
+ *   Called when a loss-of-connection event has occurred.
+ *
+ * Parameters:
+ *   psock    The TCP socket structure associated.
+ *   flags    Set of connection events events
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *   Running at the interrupt level
+ *
+ ****************************************************************************/
+
+void net_lostconnection(FAR struct socket *psock, uint16_t flags)
+{
+  DEBUGASSERT(psock)
+
+  /* These loss-of-connection events may be reported:
+   *
+   *   UIP_CLOSE: The remote host has closed the connection
+   *   UIP_ABORT: The remote host has aborted the connection
+   *   UIP_TIMEDOUT: Connection aborted due to too many retransmissions.
+   *
+   * And we need to set these two socket status bits appropriately:
+   *
+   *  _SF_CONNECTED==1 && _SF_CLOSED==0 - the socket is connected
+   *  _SF_CONNECTED==0 && _SF_CLOSED==1 - the socket was gracefully disconnected
+   *  _SF_CONNECTED==0 && _SF_CLOSED==0 - the socket was rudely disconnected
+   */
+
+  if ((flags & UIP_CLOSE) != 0)
+    {
+      /* The peer gracefully closed the connection.  Marking the
+       * connection as disconnected will suppress some subsequent
+       * ENOTCONN errors from receive.  A graceful disconnection is
+       * not handle as an error but as an "end-of-file"
+       */
+
+      psock->s_flags &= ~_SF_CONNECTED;
+      psock->s_flags |= _SF_CLOSED;
+    }
+  else if ((flags & (UIP_ABORT|UIP_TIMEDOUT)) != 0)
+    {
+      /* The loss of connection was less than graceful.  This will (eventually)
+       * be reported as an ENOTCONN error.
+       */
+
+      psock->s_flags &= ~(_SF_CONNECTED |_SF_CLOSED);
+    }
+}
+
 #endif /* CONFIG_NET && CONFIG_NET_TCP */
diff --git a/nuttx/net/recvfrom.c b/nuttx/net/recvfrom.c
index a1a6742c5..6864dace3 100644
--- a/nuttx/net/recvfrom.c
+++ b/nuttx/net/recvfrom.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * net/recvfrom.c
  *
- *   Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -464,10 +464,11 @@ static inline void recvfrom_tcpsender(struct uip_driver_s *dev, struct recvfrom_
  ****************************************************************************/
 
 #ifdef CONFIG_NET_TCP
-static uint16_t recvfrom_tcpinterrupt(struct uip_driver_s *dev, void *conn,
-                                      void *pvpriv, uint16_t flags)
+static uint16_t recvfrom_tcpinterrupt(FAR struct uip_driver_s *dev,
+                                      FAR void *conn, FAR void *pvpriv,
+                                      uint16_t flags)
 {
-  struct recvfrom_s *pstate = (struct recvfrom_s *)pvpriv;
+  FAR struct recvfrom_s *pstate = (struct recvfrom_s *)pvpriv;
 
   nllvdbg("flags: %04x\n", flags);
 
@@ -553,9 +554,7 @@ static uint16_t recvfrom_tcpinterrupt(struct uip_driver_s *dev, void *conn,
 
       else if ((flags & (UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT)) != 0)
         {
-          FAR struct socket *psock = 0;
-
-          nllvdbg("error\n");
+          nllvdbg("Lost connection\n");
 
           /* Stop further callbacks */
 
@@ -563,24 +562,14 @@ static uint16_t recvfrom_tcpinterrupt(struct uip_driver_s *dev, void *conn,
           pstate->rf_cb->priv    = NULL;
           pstate->rf_cb->event   = NULL;
 
-          /* Check if the peer gracefully closed the connection.  We need
-           * these flags in case we return zero (below) to remember the
-           * state of the connection.
-           * 
-           *   _SF_CONNECTED==0 && _SF_CLOSED==1 - the socket was
-           *     gracefully disconnected
-           *   _SF_CONNECTED==0 && _SF_CLOSED==0 - the socket was
-           *     rudely disconnected
-           */
+          /* Handle loss-of-connection event */
 
-          psock = pstate->rf_sock;
-          if ((flags & UIP_CLOSE) != 0)
-            {
-              /* Report that the connection was gracefully closed */
+          net_lostconnection(pstate->rf_sock, flags);
 
-              psock->s_flags &= ~_SF_CONNECTED;
-              psock->s_flags |= _SF_CLOSED;
+          /* Check if the peer gracefully closed the connection. */
 
+          if ((flags & UIP_CLOSE) != 0)
+            {
               /* This case should always return success (zero)! The value of
                * rf_recvlen, if zero, will indicate that the connection was
                * gracefully closed.
@@ -590,10 +579,6 @@ static uint16_t recvfrom_tcpinterrupt(struct uip_driver_s *dev, void *conn,
             }
           else
             {
-              /* Report that the connection was rudely lost */
-
-              psock->s_flags &= ~(_SF_CONNECTED |_SF_CLOSED);
-
               /* If no data has been received, then return ENOTCONN.
                * Otherwise, let this return success.  The failure will
                * be reported the next time that recv[from]() is called.
diff --git a/nuttx/net/send.c b/nuttx/net/send.c
index 8c07b391c..79dfef4ec 100644
--- a/nuttx/net/send.c
+++ b/nuttx/net/send.c
@@ -227,6 +227,8 @@ static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn,
       /* Report not connected */
 
       nllvdbg("Lost connection\n");
+
+      net_lostconnection(pstate->snd_sock, flags);
       pstate->snd_sent = -ENOTCONN;
       goto end_wait;
     }
@@ -275,10 +277,13 @@ static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn,
        *   3. Not enough data for two packets.
        *
        * Then we will split the remaining, single packet into two partial
-       * packets.  This will stimulate the RFC 1122 not into ACKing sooner.
+       * packets.  This will stimulate the RFC 1122 peer to ACK sooner.
        *
-       * Check if there is more data to be sent (more than or equal to
-       * CONFIG_NET_TCP_SPLIT_SIZE):
+       * Don't try to split very small packets (less than CONFIG_NET_TCP_SPLIT_SIZE).
+       * Only the first even packet and the last odd packets could have
+       * sndlen less than CONFIG_NET_TCP_SPLIT_SIZE.  The value of sndlen on
+       * the last even packet is guaranteed to be at least MSS/2 by the
+       * logic below.
        */
 
       if (sndlen >= CONFIG_NET_TCP_SPLIT_SIZE)