Optimized sendfile() from Max Holtzberg

27 files changed, 1151 insertions, 242 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 841d44d99..c8cf633a4 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -5663,4 +5663,7 @@
 	  tools (2013-9-27).
 	* drivers/net/encx24j500.c: Use separate pools for RX and TX
 	  descriptors.  From Max Holtzberg (2013-9-28).
+	* nuttx/fs/fs_sendfile.c, nuttx/net/net_sendfile.c, and other file:
+	  Integrate an optimized sendfile() operation from Max Holtzberg
+	  (2013-9-28).
 
diff --git a/nuttx/configs/sim/include/board.h b/nuttx/configs/sim/include/board.h
new file mode 100644
index 000000000..327ad6925
--- /dev/null
+++ b/nuttx/configs/sim/include/board.h
@@ -0,0 +1,3 @@
+/************************************************************************
+ * configs/sim/include/board.h
+ ************************************************************************/
diff --git a/nuttx/configs/sim/nsh/defconfig b/nuttx/configs/sim/nsh/defconfig
index 545469eef..01c5342b0 100644
--- a/nuttx/configs/sim/nsh/defconfig
+++ b/nuttx/configs/sim/nsh/defconfig
@@ -39,6 +39,7 @@ CONFIG_HOST_LINUX=y
 # Debug Options
 #
 # CONFIG_DEBUG is not set
+# CONFIG_ARCH_HAVE_STACKCHECK is not set
 CONFIG_DEBUG_SYMBOLS=y
 
 #
@@ -56,7 +57,6 @@ CONFIG_ARCH_SIM=y
 # CONFIG_ARCH_Z16 is not set
 # CONFIG_ARCH_Z80 is not set
 CONFIG_ARCH="sim"
-CONFIG_BOARD_LOOPSPERMSEC=0
 
 #
 # Simulation Configuration Options
@@ -65,10 +65,6 @@ CONFIG_BOARD_LOOPSPERMSEC=0
 # CONFIG_SIM_WALLTIME is not set
 
 #
-# External Memory Configuration
-#
-
-#
 # Architecture Options
 #
 # CONFIG_ARCH_NOINTC is not set
@@ -81,12 +77,13 @@ CONFIG_BOARD_LOOPSPERMSEC=0
 # CONFIG_ARCH_STACKDUMP is not set
 # CONFIG_ENDIAN_BIG is not set
 # CONFIG_ARCH_HAVE_RAMFUNCS is not set
+# CONFIG_ARCH_HAVE_RAMVECTORS is not set
 
 #
 # Board Settings
 #
-CONFIG_RAM_START=0x0
-CONFIG_RAM_SIZE=0
+CONFIG_BOARD_LOOPSPERMSEC=0
+# CONFIG_ARCH_CALIBRATION is not set
 
 #
 # Boot options
@@ -98,6 +95,12 @@ CONFIG_BOOT_RUNFROMEXTSRAM=y
 # CONFIG_BOOT_COPYTORAM is not set
 
 #
+# Boot Memory Configuration
+#
+CONFIG_RAM_START=0x0
+CONFIG_RAM_SIZE=0
+
+#
 # Board Selection
 #
 CONFIG_ARCH_BOARD_SIM=y
@@ -116,6 +119,7 @@ CONFIG_NSH_MMCSDMINOR=0
 #
 # RTOS Features
 #
+# CONFIG_BOARD_INITIALIZE is not set
 CONFIG_MSEC_PER_TICK=10
 CONFIG_RR_INTERVAL=0
 # CONFIG_SCHED_INSTRUMENTATION is not set
@@ -132,7 +136,6 @@ CONFIG_DEV_CONSOLE=y
 # CONFIG_FDCLONE_DISABLE is not set
 # CONFIG_FDCLONE_STDIO is not set
 CONFIG_SDCLONE_DISABLE=y
-# CONFIG_SCHED_WORKQUEUE is not set
 CONFIG_SCHED_WAITPID=y
 # CONFIG_SCHED_STARTHOOK is not set
 # CONFIG_SCHED_ATEXIT is not set
@@ -194,6 +197,7 @@ CONFIG_DEV_NULL=y
 # CONFIG_RTC is not set
 # CONFIG_WATCHDOG is not set
 # CONFIG_ANALOG is not set
+# CONFIG_AUDIO_DEVICES is not set
 # CONFIG_BCH is not set
 # CONFIG_INPUT is not set
 # CONFIG_LCD is not set
@@ -203,11 +207,16 @@ CONFIG_DEV_NULL=y
 # CONFIG_PM is not set
 # CONFIG_POWER is not set
 # CONFIG_SENSORS is not set
-# CONFIG_SERCOMM_CONSOLE is not set
 CONFIG_SERIAL=y
 # CONFIG_DEV_LOWCONSOLE is not set
 # CONFIG_16550_UART is not set
+
+#
+# USART Configuration
+#
 # CONFIG_STANDARD_SERIAL is not set
+# CONFIG_SERIAL_IFLOWCONTROL is not set
+# CONFIG_SERIAL_OFLOWCONTROL is not set
 # CONFIG_USBDEV is not set
 # CONFIG_USBHOST is not set
 # CONFIG_WIRELESS is not set
@@ -243,11 +252,13 @@ CONFIG_FAT_MAXFNAME=32
 # CONFIG_FAT_DMAMEMORY is not set
 # CONFIG_FS_NXFFS is not set
 CONFIG_FS_ROMFS=y
+# CONFIG_FS_SMARTFS is not set
 CONFIG_FS_BINFS=y
 
 #
 # System Logging
 #
+# CONFIG_SYSLOG_ENABLE is not set
 # CONFIG_SYSLOG is not set
 
 #
@@ -258,11 +269,17 @@ CONFIG_FS_BINFS=y
 #
 # Memory Management
 #
+# CONFIG_MM_MULTIHEAP is not set
 # CONFIG_MM_SMALL is not set
 CONFIG_MM_REGIONS=1
 # CONFIG_GRAN is not set
 
 #
+# Audio Support
+#
+# CONFIG_AUDIO is not set
+
+#
 # Binary Formats
 #
 # CONFIG_BINFMT_DISABLE is not set
@@ -288,6 +305,7 @@ CONFIG_LIB_HOMEDIR="/"
 # CONFIG_LIBM is not set
 # CONFIG_NOPRINTF_FIELDWIDTH is not set
 # CONFIG_LIBC_FLOATINGPOINT is not set
+CONFIG_LIB_RAND_ORDER=1
 # CONFIG_EOL_IS_CR is not set
 # CONFIG_EOL_IS_LF is not set
 # CONFIG_EOL_IS_BOTH_CRLF is not set
@@ -296,6 +314,7 @@ CONFIG_LIBC_EXECFUNCS=y
 CONFIG_EXECFUNCS_SYMTAB="g_symtab"
 CONFIG_EXECFUNCS_NSYMBOLS=0
 CONFIG_POSIX_SPAWN_PROXY_STACKSIZE=1024
+CONFIG_TASK_SPAWN_DEFAULT_STACKSIZE=2048
 # CONFIG_LIBC_STRERROR is not set
 # CONFIG_LIBC_PERROR_STDOUT is not set
 CONFIG_ARCH_LOWPUTC=y
@@ -304,9 +323,11 @@ CONFIG_LIB_SENDFILE_BUFSIZE=512
 # CONFIG_ARCH_OPTIMIZED_FUNCTIONS is not set
 
 #
-# Non-standard Helper Functions
+# Non-standard Library Support
 #
+# CONFIG_SCHED_WORKQUEUE is not set
 # CONFIG_LIB_KBDCODEC is not set
+# CONFIG_LIB_SLCDCODEC is not set
 
 #
 # Basic CXX Support
@@ -328,8 +349,6 @@ CONFIG_BUILTIN_PROXY_STACKSIZE=1024
 #
 # CONFIG_EXAMPLES_BUTTONS is not set
 # CONFIG_EXAMPLES_CAN is not set
-# CONFIG_SYSTEM_CDCACM is not set
-# CONFIG_SYSTEM_COMPOSITE is not set
 # CONFIG_EXAMPLES_DHCPD is not set
 # CONFIG_EXAMPLES_ELF is not set
 # CONFIG_EXAMPLES_FTPC is not set
@@ -342,8 +361,9 @@ CONFIG_EXAMPLES_HELLO=y
 # CONFIG_EXAMPLES_IGMP is not set
 # CONFIG_EXAMPLES_LCDRW is not set
 # CONFIG_EXAMPLES_MM is not set
-# CONFIG_EXAMPLES_MOUNT is not set
 # CONFIG_EXAMPLES_MODBUS is not set
+# CONFIG_EXAMPLES_MOUNT is not set
+# CONFIG_EXAMPLES_NRF24L01TERM is not set
 CONFIG_EXAMPLES_NSH=y
 # CONFIG_EXAMPLES_NULL is not set
 # CONFIG_EXAMPLES_NX is not set
@@ -363,6 +383,10 @@ CONFIG_EXAMPLES_NSH=y
 # CONFIG_EXAMPLES_ROMFS is not set
 # CONFIG_EXAMPLES_SENDMAIL is not set
 # CONFIG_EXAMPLES_SERLOOP is not set
+# CONFIG_EXAMPLES_SLCD is not set
+# CONFIG_EXAMPLES_SMART_TEST is not set
+# CONFIG_EXAMPLES_SMART is not set
+# CONFIG_EXAMPLES_TCPECHO is not set
 # CONFIG_EXAMPLES_TELNETD is not set
 # CONFIG_EXAMPLES_THTTPD is not set
 # CONFIG_EXAMPLES_TIFF is not set
@@ -370,13 +394,13 @@ CONFIG_EXAMPLES_NSH=y
 # CONFIG_EXAMPLES_UDP is not set
 # CONFIG_EXAMPLES_UIP is not set
 # CONFIG_EXAMPLES_USBSERIAL is not set
-# CONFIG_SYSTEM_USBMSC is not set
 # CONFIG_EXAMPLES_USBTERM is not set
 # CONFIG_EXAMPLES_WATCHDOG is not set
 
 #
-# Interpreters
+# Graphics Support
 #
+# CONFIG_TIFF is not set
 
 #
 # Interpreters
@@ -406,11 +430,7 @@ CONFIG_EXAMPLES_NSH=y
 # CONFIG_NETUTILS_WEBCLIENT is not set
 
 #
-# ModBus
-#
-
-#
-# FreeModbus
+# FreeModBus
 #
 # CONFIG_MODBUS is not set
 
@@ -427,6 +447,7 @@ CONFIG_NSH_FILE_APPS=y
 # CONFIG_NSH_DISABLE_CAT is not set
 # CONFIG_NSH_DISABLE_CD is not set
 # CONFIG_NSH_DISABLE_CP is not set
+# CONFIG_NSH_DISABLE_CMP is not set
 # CONFIG_NSH_DISABLE_DD is not set
 # CONFIG_NSH_DISABLE_ECHO is not set
 # CONFIG_NSH_DISABLE_EXEC is not set
@@ -463,22 +484,34 @@ CONFIG_NSH_FILE_APPS=y
 # CONFIG_NSH_DISABLE_USLEEP is not set
 # CONFIG_NSH_DISABLE_WGET is not set
 # CONFIG_NSH_DISABLE_XD is not set
+
+#
+# Configure Command Options
+#
+# CONFIG_NSH_CMDOPT_DF_H is not set
 CONFIG_NSH_CODECS_BUFSIZE=128
 CONFIG_NSH_FILEIOSIZE=1024
 CONFIG_NSH_LINELEN=80
+CONFIG_NSH_MAXARGUMENTS=6
 CONFIG_NSH_NESTDEPTH=3
 # CONFIG_NSH_DISABLESCRIPT is not set
 # CONFIG_NSH_DISABLEBG is not set
 CONFIG_NSH_ROMFSETC=y
+# CONFIG_NSH_ROMFSRC is not set
 CONFIG_NSH_ROMFSMOUNTPT="/etc"
 CONFIG_NSH_INITSCRIPT="init.d/rcS"
 CONFIG_NSH_ROMFSDEVNO=1
 CONFIG_NSH_ROMFSSECTSIZE=64
+# CONFIG_NSH_ARCHROMFS is not set
 CONFIG_NSH_FATDEVNO=2
 CONFIG_NSH_FATSECTSIZE=512
 CONFIG_NSH_FATNSECTORS=1024
 CONFIG_NSH_FATMOUNTPT="/tmp"
 CONFIG_NSH_CONSOLE=y
+
+#
+# USB Trace Support
+#
 # CONFIG_NSH_CONDEV is not set
 # CONFIG_NSH_ARCHINIT is not set
 
@@ -491,6 +524,14 @@ CONFIG_NSH_CONSOLE=y
 #
 
 #
+# USB CDC/ACM Device Commands
+#
+
+#
+# USB Composite Device Commands
+#
+
+#
 # Custom Free Memory Command
 #
 # CONFIG_SYSTEM_FREE is not set
@@ -505,6 +546,15 @@ CONFIG_NSH_CONSOLE=y
 # CONFIG_SYSTEM_INSTALL is not set
 
 #
+# FLASH Erase-all Command
+#
+
+#
+# RAM test
+#
+# CONFIG_SYSTEM_RAMTEST is not set
+
+#
 # readline()
 #
 CONFIG_SYSTEM_READLINE=y
@@ -529,3 +579,20 @@ CONFIG_READLINE_ECHO=y
 # Sysinfo
 #
 # CONFIG_SYSTEM_SYSINFO is not set
+
+#
+# USB Monitor
+#
+
+#
+# Stack Monitor
+#
+
+#
+# USB Mass Storage Device Commands
+#
+
+#
+# Zmodem Commands
+#
+# CONFIG_SYSTEM_ZMODEM is not set
diff --git a/nuttx/fs/Makefile b/nuttx/fs/Makefile
index d9e0900fa..deb98bd44 100644
--- a/nuttx/fs/Makefile
+++ b/nuttx/fs/Makefile
@@ -83,6 +83,12 @@ ifneq ($(CONFIG_NFILE_STREAMS),0)
 CSRCS	+= fs_fdopen.c 
 endif
 
+# Support for sendfile()
+
+ifeq ($(CONFIG_NET_SENDFILE),y)
+CSRCS += fs_sendfile.c
+endif
+
 # System logging to a character device (or file)
 
 ifeq ($(CONFIG_SYSLOG),y)
diff --git a/nuttx/fs/fs_fcntl.c b/nuttx/fs/fs_fcntl.c
index 20c05a439..db814f210 100644
--- a/nuttx/fs/fs_fcntl.c
+++ b/nuttx/fs/fs_fcntl.c
@@ -42,6 +42,7 @@
 #include <stdarg.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <assert.h>
 
 #include <nuttx/fs/fs.h>
 #include <nuttx/net/net.h>
@@ -62,26 +63,22 @@
  ****************************************************************************/
 
 #if CONFIG_NFILE_DESCRIPTORS > 0
-static inline int file_vfcntl(int fildes, int cmd, va_list ap)
+static inline int file_vfcntl(int fd, int cmd, va_list ap)
 {
   FAR struct filelist *list;
-  FAR struct file *this_file;
+  FAR struct file *filep;
   int err = 0;
   int ret = OK;
 
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      err = EMFILE;
-      goto errout;
-    }
+  DEBUGASSERT(list);
 
   /* Was this file opened ? */
 
-  this_file = &list->fl_files[fildes];
-  if (!this_file->f_inode)
+  filep = &list->fl_files[fd];
+  if (!filep->f_inode)
     {
       err = EBADF;
       goto errout;
@@ -101,20 +98,20 @@ static inline int file_vfcntl(int fildes, int cmd, va_list ap)
          */
 
         {
-          ret = file_dup(fildes, va_arg(ap, int));
+          ret = file_dup(fd, va_arg(ap, int));
         }
         break;
 
       case F_GETFD:
         /* Get the file descriptor flags defined in <fcntl.h> that are associated
-         * with the file descriptor fildes.  File descriptor flags are associated
+         * with the file descriptor fd.  File descriptor flags are associated
          * with a single file descriptor and do not affect other file descriptors
          * that refer to the same file.
          */
 
       case F_SETFD:
         /* Set the file descriptor flags defined in <fcntl.h>, that are associated
-         * with fildes, to the third argument, arg, taken as type int. If the
+         * with fd, to the third argument, arg, taken as type int. If the
          * FD_CLOEXEC flag in the third argument is 0, the file shall remain open
          * across the exec functions; otherwise, the file shall be closed upon
          * successful execution of one  of  the  exec  functions.
@@ -125,7 +122,7 @@ static inline int file_vfcntl(int fildes, int cmd, va_list ap)
 
       case F_GETFL:
         /* Get the file status flags and file access modes, defined in <fcntl.h>,
-         * for the file description associated with fildes. The file access modes
+         * for the file description associated with fd. The file access modes
          * can be extracted from the return value using the mask O_ACCMODE, which is
          * defined  in <fcntl.h>. File status flags and file access modes are associated
          * with the file description and do not affect other file descriptors that
@@ -133,13 +130,13 @@ static inline int file_vfcntl(int fildes, int cmd, va_list ap)
          */
 
         {
-          ret = this_file->f_oflags;
+          ret = filep->f_oflags;
         }
         break;
 
       case F_SETFL:
         /* Set the file status flags, defined in <fcntl.h>, for the file description
-         * associated with fildes from the corresponding  bits in the third argument,
+         * associated with fd from the corresponding  bits in the third argument,
          * arg, taken as type int. Bits corresponding to the file access mode and
          * the file creation flags, as defined in <fcntl.h>, that are set in arg shall
          * be ignored. If any bits in arg other than those mentioned here are changed
@@ -149,25 +146,25 @@ static inline int file_vfcntl(int fildes, int cmd, va_list ap)
         {
           int oflags = va_arg(ap, int);
 
-          oflags              &=  FFCNTL;
-          this_file->f_oflags &= ~FFCNTL;
-          this_file->f_oflags |=  oflags;
+          oflags          &=  FFCNTL;
+          filep->f_oflags &= ~FFCNTL;
+          filep->f_oflags |=  oflags;
         }
         break;
 
       case F_GETOWN:
-        /* If fildes refers to a socket, get the process or process group ID specified
+        /* If fd refers to a socket, get the process or process group ID specified
          * to receive SIGURG signals when out-of-band data is available. Positive values
          * indicate a process ID; negative values, other than -1, indicate a process group
-         * ID. If fildes does not refer to a socket, the results are unspecified.
+         * ID. If fd does not refer to a socket, the results are unspecified.
          */
 
       case F_SETOWN:
-        /* If fildes refers to a socket, set the process or process group ID specified
+        /* If fd refers to a socket, set the process or process group ID specified
          * to receive SIGURG signals when out-of-band data is available, using the value
          * of the third argument, arg, taken as type int. Positive values indicate a 
          * process ID; negative values, other than -1, indicate a process group ID. If
-         * fildes does not refer to a socket, the results are unspecified.
+         * fd does not refer to a socket, the results are unspecified.
          */
 
         err = EBADF; /* Only valid on socket descriptors */
@@ -227,7 +224,7 @@ errout:
  * Name: fcntl
  ****************************************************************************/
 
-int fcntl(int fildes, int cmd, ...)
+int fcntl(int fd, int cmd, ...)
 {
   va_list ap;
   int ret;
@@ -239,11 +236,11 @@ int fcntl(int fildes, int cmd, ...)
   /* Did we get a valid file descriptor? */
 
 #if CONFIG_NFILE_DESCRIPTORS > 0
-  if ((unsigned int)fildes < CONFIG_NFILE_DESCRIPTORS)
+  if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS)
     {
        /* Yes.. defer file operations to file_vfcntl() */
 
-       ret = file_vfcntl(fildes, cmd, ap);
+       ret = file_vfcntl(fd, cmd, ap);
     }
   else
 #endif
@@ -251,11 +248,11 @@ int fcntl(int fildes, int cmd, ...)
       /* No... check for operations on a socket descriptor */
 
 #if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
-      if ((unsigned int)fildes < (CONFIG_NFILE_DESCRIPTORS+CONFIG_NSOCKET_DESCRIPTORS))
+      if ((unsigned int)fd < (CONFIG_NFILE_DESCRIPTORS+CONFIG_NSOCKET_DESCRIPTORS))
         {
           /* Yes.. defer socket descriptor operations to net_vfcntl() */
 
-          ret = net_vfcntl(fildes, cmd, ap);
+          ret = net_vfcntl(fd, cmd, ap);
         }
       else
 #endif
diff --git a/nuttx/fs/fs_filedup.c b/nuttx/fs/fs_filedup.c
index b7eeb7add..dcc229ab3 100644
--- a/nuttx/fs/fs_filedup.c
+++ b/nuttx/fs/fs_filedup.c
@@ -41,6 +41,7 @@
 
 #include <sched.h>
 #include <errno.h>
+#include <assert.h>
 
 #include <nuttx/fs/fs.h>
 
@@ -84,11 +85,7 @@ int file_dup(int fildes, int minfd)
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      set_errno(EMFILE);
-      return ERROR;
-    }
+  DEBUGASSERT(list);
 
   /* Verify that fildes is a valid, open file descriptor */
 
diff --git a/nuttx/fs/fs_files.c b/nuttx/fs/fs_files.c
index c68ec7e73..739947a7d 100644
--- a/nuttx/fs/fs_files.c
+++ b/nuttx/fs/fs_files.c
@@ -222,11 +222,7 @@ int files_dup(FAR struct file *filep1, FAR struct file *filep2)
     }
 
   list = sched_getfiles();
-  if (!list)
-    {
-      err = EMFILE;
-      goto errout;
-    }
+  DEBUGASSERT(list);
 
   _files_semtake(list);
 
@@ -317,25 +313,23 @@ int files_allocate(FAR struct inode *inode, int oflags, off_t pos, int minfd)
   int i;
 
   list = sched_getfiles();
-  if (list)
+  DEBUGASSERT(list);
+
+  _files_semtake(list);
+  for (i = minfd; i < CONFIG_NFILE_DESCRIPTORS; i++)
     {
-      _files_semtake(list);
-      for (i = minfd; i < CONFIG_NFILE_DESCRIPTORS; i++)
+      if (!list->fl_files[i].f_inode)
         {
-          if (!list->fl_files[i].f_inode)
-            {
-               list->fl_files[i].f_oflags = oflags;
-               list->fl_files[i].f_pos    = pos;
-               list->fl_files[i].f_inode  = inode;
-               list->fl_files[i].f_priv   = NULL;
-               _files_semgive(list);
-               return i;
-            }
+           list->fl_files[i].f_oflags = oflags;
+           list->fl_files[i].f_pos    = pos;
+           list->fl_files[i].f_inode  = inode;
+           list->fl_files[i].f_priv   = NULL;
+           _files_semgive(list);
+           return i;
         }
-
-      _files_semgive(list);
     }
 
+  _files_semgive(list);
   return ERROR;
 }
 
@@ -358,10 +352,7 @@ int files_close(int filedes)
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      return -EMFILE;
-    }
+  DEBUGASSERT(list);
 
   /* If the file was properly opened, there should be an inode assigned */
 
@@ -392,16 +383,15 @@ void files_release(int filedes)
   FAR struct filelist *list;
 
   list = sched_getfiles();
-  if (list)
+  DEBUGASSERT(list);
+
+  if (filedes >=0 && filedes < CONFIG_NFILE_DESCRIPTORS)
     {
-      if (filedes >=0 && filedes < CONFIG_NFILE_DESCRIPTORS)
-        {
-          _files_semtake(list);
-          list->fl_files[filedes].f_oflags  = 0;
-          list->fl_files[filedes].f_pos     = 0;
-          list->fl_files[filedes].f_inode = NULL;
-          _files_semgive(list);
-        }
+      _files_semtake(list);
+      list->fl_files[filedes].f_oflags  = 0;
+      list->fl_files[filedes].f_pos     = 0;
+      list->fl_files[filedes].f_inode = NULL;
+      _files_semgive(list);
     }
 }
 
diff --git a/nuttx/fs/fs_fsync.c b/nuttx/fs/fs_fsync.c
index 877c33a83..49104ed02 100644
--- a/nuttx/fs/fs_fsync.c
+++ b/nuttx/fs/fs_fsync.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * fs/fs_fsync.c
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -42,6 +42,8 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <assert.h>
+
 #include <nuttx/fs/fs.h>
 #include <nuttx/sched.h>
 
@@ -78,18 +80,14 @@
 int fsync(int fd)
 {
   FAR struct filelist *list;
-  FAR struct file     *this_file;
+  FAR struct file     *filep;
   struct inode        *inode;
   int                  ret;
 
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      ret = EMFILE;
-      goto errout;
-    }
+  DEBUGASSERT(list);
 
   /* Did we get a valid file descriptor? */
 
@@ -101,8 +99,8 @@ int fsync(int fd)
 
   /* Was this file opened for write access? */
 
-  this_file = &list->fl_files[fd];
-  if ((this_file->f_oflags & O_WROK) == 0)
+  filep = &list->fl_files[fd];
+  if ((filep->f_oflags & O_WROK) == 0)
     {
       ret = EBADF;
       goto errout;
@@ -113,7 +111,7 @@ int fsync(int fd)
    * the mountpoint operations vtable contains a sync method.
    */
 
-  inode = this_file->f_inode;
+  inode = filep->f_inode;
   if (!inode || !INODE_IS_MOUNTPT(inode) ||
       !inode->u.i_mops || !inode->u.i_mops->sync)
     {
@@ -123,7 +121,7 @@ int fsync(int fd)
 
   /* Yes, then tell the mountpoint to sync this file */
 
-  ret = inode->u.i_mops->sync(this_file);
+  ret = inode->u.i_mops->sync(filep);
   if (ret >= 0)
     {
       return OK;
diff --git a/nuttx/fs/fs_ioctl.c b/nuttx/fs/fs_ioctl.c
index 3440bc0d0..89b7b3f51 100644
--- a/nuttx/fs/fs_ioctl.c
+++ b/nuttx/fs/fs_ioctl.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * fs/fs_ioctl.c
  *
- *   Copyright (C) 2007-2010, 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2010, 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -42,6 +42,7 @@
 #include <sys/ioctl.h>
 #include <sched.h>
 #include <errno.h>
+#include <assert.h>
 
 #include <net/if.h>
 
@@ -89,7 +90,7 @@ int ioctl(int fd, int req, unsigned long arg)
   int err;
 #if CONFIG_NFILE_DESCRIPTORS > 0
   FAR struct filelist *list;
-  FAR struct file     *this_file;
+  FAR struct file     *filep;
   FAR struct inode    *inode;
   int                  ret = OK;
 
@@ -117,22 +118,18 @@ int ioctl(int fd, int req, unsigned long arg)
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      err = EMFILE;
-      goto errout;
-    }
+  DEBUGASSERT(list);
 
   /* Is a driver registered? Does it support the ioctl method? */
 
-  this_file = &list->fl_files[fd];
-  inode     = this_file->f_inode;
+  filep = &list->fl_files[fd];
+  inode = filep->f_inode;
 
   if (inode && inode->u.i_ops && inode->u.i_ops->ioctl)
     {
       /* Yes, then let it perform the ioctl */
 
-      ret = (int)inode->u.i_ops->ioctl(this_file, req, arg);
+      ret = (int)inode->u.i_ops->ioctl(filep, req, arg);
       if (ret < 0)
         {
           err = -ret;
diff --git a/nuttx/fs/fs_lseek.c b/nuttx/fs/fs_lseek.c
index c57658434..bcf66f51b 100644
--- a/nuttx/fs/fs_lseek.c
+++ b/nuttx/fs/fs_lseek.c
@@ -43,6 +43,7 @@
 #include <unistd.h>
 #include <sched.h>
 #include <errno.h>
+#include <assert.h>
 
 #include "fs_internal.h"
 
@@ -53,6 +54,86 @@
  ****************************************************************************/
 
 /****************************************************************************
+ * Name: file_seek
+ *
+ * Description:
+ *   This is the internal implementation of lseek.  See the comments in
+ *   lseek() for further information.
+ *
+ * Parameters:
+ *   file     File structure instance
+ *   offset   Defines the offset to position to
+ *   whence   Defines how to use offset
+ *
+ * Return:
+ *   The resulting offset on success.  -1 on failure withi errno set
+ *   properly (see lseek comments).
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_NET_SENDFILE
+static inline
+#endif
+off_t file_seek(FAR struct file *filep, off_t offset, int whence)
+{
+  FAR struct inode *inode;
+  int ret;
+  int err = OK;
+
+  DEBUGASSERT(seekfile);
+  inode =  filep->f_inode;
+
+  /* Invoke the file seek method if available */
+
+  if (inode && inode->u.i_ops && inode->u.i_ops->seek)
+    {
+      ret = (int)inode->u.i_ops->seek(filep, offset, whence);
+      if (ret < 0)
+        {
+          err = -ret;
+          goto errout;
+        }
+    }
+  else
+    {
+      /* No... Just set the common file position value */
+
+      switch (whence)
+        {
+          case SEEK_CUR:
+            offset += filep->f_pos;
+
+          case SEEK_SET:
+            if (offset >= 0)
+              {
+                filep->f_pos = offset; /* Might be beyond the end-of-file */
+                break;
+              }
+            else
+              {
+                err = EINVAL;
+                goto errout;
+              }
+            break;
+
+          case SEEK_END:
+            err = ENOSYS;
+            goto errout;
+
+          default:
+            err = EINVAL;
+            goto errout;
+        }
+    }
+
+  return filep->f_pos;
+
+errout:
+  set_errno(err);
+  return (off_t)ERROR;
+}
+
+/****************************************************************************
  * Name: lseek
  *
  * Description:
@@ -100,77 +181,18 @@ off_t lseek(int fd, off_t offset, int whence)
 
   if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
     {
-      err = EBADF;
-      goto errout;
+      set_errno(EBADF);
+      return (off_t)ERROR;
     }
 
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      err = EMFILE;
-      goto errout;
-    }
-
-  /* Is a driver registered? */
+  DEBUGASSERT(list);
 
-  filep = &list->fl_files[fd];
-  inode =  filep->f_inode;
-
-  if (inode && inode->u.i_ops)
-    {
-      /* Does it support the seek method */
+  /* Then let file_seek do the real work */
 
-      if (inode->u.i_ops->seek)
-        {
-          /* Yes, then let it perform the seek */
-
-          err = (int)inode->u.i_ops->seek(filep, offset, whence);
-          if (err < 0)
-            {
-              err = -err;
-              goto errout;
-            }
-         }
-      else
-        {
-          /* No... there are a couple of default actions we can take */
-
-          switch (whence)
-            {
-              case SEEK_CUR:
-                offset += filep->f_pos;
-
-              case SEEK_SET:
-                if (offset >= 0)
-                  {
-                    filep->f_pos = offset; /* Might be beyond the end-of-file */
-                    break;
-                  }
-                else
-                  {
-                    err = EINVAL;
-                    goto errout;
-                  }
-                break;
-
-              case SEEK_END:
-                err = ENOSYS;
-                goto errout;
-
-              default:
-                err = EINVAL;
-                goto errout;
-            }
-        }
-    }
-
-  return filep->f_pos;
-
-errout:
-  set_errno(err);
-  return (off_t)ERROR;
+  return file_seek(&list->fl_files[fd], offset, whence);
 }
 
 #endif
diff --git a/nuttx/fs/fs_open.c b/nuttx/fs/fs_open.c
index 5b318b702..aead99f8f 100644
--- a/nuttx/fs/fs_open.c
+++ b/nuttx/fs/fs_open.c
@@ -38,14 +38,18 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+
 #include <sys/types.h>
 #include <fcntl.h>
 #include <sched.h>
 #include <errno.h>
+#include <assert.h>
 #ifdef CONFIG_FILE_MODE
 #include <stdarg.h>
 #endif
+
 #include <nuttx/fs/fs.h>
+
 #include "fs_internal.h"
 
 /****************************************************************************
@@ -99,11 +103,7 @@ int open(const char *path, int oflags, ...)
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      ret = EMFILE;
-      goto errout;
-    }
+  DEBUGASSERT(list);
 
 #ifdef CONFIG_FILE_MODE
 #  ifdef CONFIG_CPP_HAVE_WARNING
diff --git a/nuttx/fs/fs_poll.c b/nuttx/fs/fs_poll.c
index 52d7f94a8..b86d6933e 100644
--- a/nuttx/fs/fs_poll.c
+++ b/nuttx/fs/fs_poll.c
@@ -97,7 +97,7 @@ static void poll_semtake(FAR sem_t *sem)
 static int poll_fdsetup(int fd, FAR struct pollfd *fds, bool setup)
 {
   FAR struct filelist *list;
-  FAR struct file     *this_file;
+  FAR struct file     *filep;
   FAR struct inode    *inode;
   int                  ret = -ENOSYS;
 
@@ -122,23 +122,20 @@ static int poll_fdsetup(int fd, FAR struct pollfd *fds, bool setup)
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      return -EMFILE;
-    }
+  DEBUGASSERT(list);
 
   /* Is a driver registered? Does it support the poll method?
    * If not, return -ENOSYS
    */
 
-  this_file = &list->fl_files[fd];
-  inode     = this_file->f_inode;
+  filep = &list->fl_files[fd];
+  inode = filep->f_inode;
 
   if (inode && inode->u.i_ops && inode->u.i_ops->poll)
     {
       /* Yes, then setup the poll */
 
-      ret = (int)inode->u.i_ops->poll(this_file, fds, setup);
+      ret = (int)inode->u.i_ops->poll(filep, fds, setup);
     }
 
   return ret;
diff --git a/nuttx/fs/fs_read.c b/nuttx/fs/fs_read.c
index 30dd4af03..5a7e6cb18 100644
--- a/nuttx/fs/fs_read.c
+++ b/nuttx/fs/fs_read.c
@@ -1,7 +1,7 @@
 /****************************************************************************
- * fs_read.c
+ * fs/fs_read.c
  *
- *   Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -52,51 +52,60 @@
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: file_read
+ *
+ * Description:
+ *   This is the internal implementation of read().
+ *
+ * Parameters:
+ *   file     File structure instance
+ *   buf      User-provided to save the data
+ *   nbytes   The maximum size of the user-provided buffer
+ *
+ * Return:
+ *   The positive non-zero number of bytes read on success, 0 on if an
+ *   end-of-file condition, or -1 on failure withi errno set appropriately.
+ *
+ ****************************************************************************/
+
 #if CONFIG_NFILE_DESCRIPTORS > 0
-static inline ssize_t file_read(int fd, FAR void *buf, size_t nbytes)
+#ifndef CONFIG_NET_SENDFILE
+static inline
+#endif
+ssize_t file_read(FAR struct file *filep, FAR void *buf, size_t nbytes)
 {
-  FAR struct filelist *list;
+  FAR struct inode *inode;
   int ret = -EBADF;
 
-  /* Get the thread-specific file list */
+  DEBUGASSERT(filep);
+  inode = filep->f_inode;
+
+  /* Was this file opened for read access? */
 
-  list = sched_getfiles();
-  if (!list)
+  if ((filep->f_oflags & O_RDOK) == 0)
     {
-      /* Failed to get the file list */
+      /* No.. File is not read-able */
 
-      ret = -EMFILE;
+      ret = -EACCES;
     }
 
-  /* Were we given a valid file descriptor? */
+  /* Is a driver or mountpoint registered? If so, does it support the read
+   * method?
+   */
 
-  else if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS)
+  else if (inode && inode->u.i_ops && inode->u.i_ops->read)
     {
-      FAR struct file *this_file = &list->fl_files[fd];
-      FAR struct inode *inode    = this_file->f_inode;
-
-      /* Yes.. Was this file opened for read access? */
-
-      if ((this_file->f_oflags & O_RDOK) == 0)
-        {
-          /* No.. File is not read-able */
-
-          ret = -EACCES;
-        }
-
-      /* Is a driver or mountpoint registered? If so, does it support
-       * the read method?
+      /* Yes.. then let it perform the read.  NOTE that for the case of the
+       * mountpoint, we depend on the read methods bing identical in
+       * signature and position in the operations vtable.
        */
 
-      else if (inode && inode->u.i_ops && inode->u.i_ops->read)
-        {
-          /* Yes.. then let it perform the read.  NOTE that for the case
-           * of the mountpoint, we depend on the read methods bing
-           * identical in signature and position in the operations vtable.
-           */
-
-          ret = (int)inode->u.i_ops->read(this_file, (char*)buf, (size_t)nbytes);
-        }
+      ret = (int)inode->u.i_ops->read(filep, (char*)buf, (size_t)nbytes);
     }
 
   /* If an error occurred, set errno and return -1 (ERROR) */
@@ -111,14 +120,31 @@ static inline ssize_t file_read(int fd, FAR void *buf, size_t nbytes)
 
   return ret;
 }
-#endif
+#endif /* CONFIG_NFILE_DESCRIPTORS > 0 */
 
 /****************************************************************************
- * Public Functions
+ * Name: read
+ *
+ * Description:
+ *   The standard, POSIX read interface.
+ *
+ * Parameters:
+ *   file     File structure instance
+ *   buf      User-provided to save the data
+ *   nbytes   The maximum size of the user-provided buffer
+ *
+ * Return:
+ *   The positive non-zero number of bytes read on success, 0 on if an
+ *   end-of-file condition, or -1 on failure withi errno set appropriately.
+ *
  ****************************************************************************/
 
 ssize_t read(int fd, FAR void *buf, size_t nbytes)
 {
+#if CONFIG_NFILE_DESCRIPTORS > 0
+  FAR struct filelist *list;
+#endif
+
   /* Did we get a valid file descriptor? */
 
 #if CONFIG_NFILE_DESCRIPTORS > 0
@@ -139,9 +165,19 @@ ssize_t read(int fd, FAR void *buf, size_t nbytes)
 #endif
     }
 
-  /* The descriptor is in a valid range to file descriptor... do the read */
-
 #if CONFIG_NFILE_DESCRIPTORS > 0
-  return file_read(fd, buf, nbytes);
+  else
+    {
+      /* Thee descriptor is in a valid range to file descriptor... do the
+       * read. Get the thread-specific file list.
+       */
+
+      list = sched_getfiles();
+      DEBUGASSERT(list);
+
+      /* Then let file_read do all of the work */
+
+      return file_read(&list->fl_files[fd], buf, nbytes);
+    }
 #endif
 }
diff --git a/nuttx/fs/fs_sendfile.c b/nuttx/fs/fs_sendfile.c
new file mode 100644
index 000000000..39533a4f2
--- /dev/null
+++ b/nuttx/fs/fs_sendfile.c
@@ -0,0 +1,154 @@
+/************************************************************************
+ * fs/fs_sendfile.c
+ *
+ *   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
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************/
+
+/************************************************************************
+ * Included Files
+ ************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/sendfile.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <nuttx/sched.h>
+#include <nuttx/net/net.h>
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NET_SENDFILE
+
+/************************************************************************
+ * Private types
+ ************************************************************************/
+
+/************************************************************************
+ * Private Variables
+ ************************************************************************/
+
+/************************************************************************
+ * Public Variables
+ ************************************************************************/
+
+/************************************************************************
+ * Private Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Public Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Name: sendfile
+ *
+ * Description:
+ *   sendfile() copies data between one file descriptor and another.
+ *   Used with file descriptors it basically just wraps a sequence of
+ *   reads() and writes() to perform a copy.
+ *
+ *   If the destination descriptor is a socket, it gives a better
+ *   performance than simple reds() and writes(). The data is read directly
+ *   into the net buffer and the whole tcp window is filled if possible.
+ *
+ *   NOTE: This interface is *not* specified in POSIX.1-2001, or other
+ *   standards.  The implementation here is very similar to the Linux
+ *   sendfile interface.  Other UNIX systems implement sendfile() with
+ *   different semantics and prototypes.  sendfile() should not be used
+ *   in portable programs.
+ *
+ * Input Parmeters:
+ *   infd   - A file (or socket) descriptor opened for reading
+ *   outfd  - A descriptor opened for writing.
+ *   offset - If 'offset' is not NULL, then it points to a variable
+ *            holding the file offset from which sendfile() will start
+ *            reading data from 'infd'.  When sendfile() returns, this
+ *            variable will be set to the offset of the byte following
+ *            the last byte that was read.  If 'offset' is not NULL,
+ *            then sendfile() does not modify the current file offset of
+ *            'infd'; otherwise the current file offset is adjusted to
+ *            reflect the number of bytes read from 'infd.'
+ *
+ *            If 'offset' is NULL, then data will be read from 'infd'
+ *            starting at the current file offset, and the file offset
+ *            will be updated by the call.
+ *   count -  The number of bytes to copy between the file descriptors.
+ *
+ * Returned Value:
+ *   If the transfer was successful, the number of bytes written to outfd is
+ *   returned.  On error, -1 is returned, and errno is set appropriately.
+ *   There error values are those returned by read() or write() plus:
+ *
+ *   EINVAL - Bad input parameters.
+ *   ENOMEM - Could not allocated an I/O buffer
+ *
+ ************************************************************************/
+
+ssize_t sendfile(int outfd, int infd, off_t *offset, size_t count)
+{
+#if defined(CONFIG_NET_TCP) && CONFIG_NSOCKET_DESCRIPTORS > 0
+
+  /* Check the destination file descriptor:  Is it a (probable) file
+   * descriptor?  Check the source file:  Is it a normal file?
+   */
+
+  if ((unsigned int)outfd >= CONFIG_NFILE_DESCRIPTORS &&
+      (unsigned int)infd < CONFIG_NFILE_DESCRIPTORS)
+    {
+      FAR struct filelist *list;
+
+      /* This appears to be a file-to-socket transfer.  Get the thread-
+       * specific file list.
+       */
+
+      list = sched_getfiles();
+      DEBUGASSERT(list);
+
+      /* Then let net_sendfile do the work. */
+
+      return net_sendfile(outfd, &list->fl_files[infd], offset, count);
+    }
+  else
+#endif
+    {
+      /* No... then this is probably a file-to-file transfer.  The generic
+       * lib_sendfile() can handle that case.
+       */
+
+      return lib_sendfile(outfd, infd, offset, count);
+    }
+}
+
+#endif /* CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NET_SENDFILE */
diff --git a/nuttx/fs/fs_write.c b/nuttx/fs/fs_write.c
index 93dad92c4..7b6a8172f 100644
--- a/nuttx/fs/fs_write.c
+++ b/nuttx/fs/fs_write.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * fs/fs_write.c
  *
- *   Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -43,6 +43,7 @@
 #include <fcntl.h>
 #include <sched.h>
 #include <errno.h>
+#include <assert.h>
 
 #if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
 # include <sys/socket.h>
@@ -58,7 +59,7 @@
 static inline ssize_t file_write(int fd, FAR const void *buf, size_t nbytes)
 {
   FAR struct filelist *list;
-  FAR struct file *this_file;
+  FAR struct file *filep;
   FAR struct inode *inode;
   int ret;
   int err;
@@ -66,16 +67,12 @@ static inline ssize_t file_write(int fd, FAR const void *buf, size_t nbytes)
   /* Get the thread-specific file list */
 
   list = sched_getfiles();
-  if (!list)
-    {
-      err = EMFILE;
-      goto errout;
-    }
+  DEBUGASSERT(list);
 
   /* Was this file opened for write access? */
 
-  this_file = &list->fl_files[fd];
-  if ((this_file->f_oflags & O_WROK) == 0)
+  filep = &list->fl_files[fd];
+  if ((filep->f_oflags & O_WROK) == 0)
     {
       err = EBADF;
       goto errout;
@@ -83,7 +80,7 @@ static inline ssize_t file_write(int fd, FAR const void *buf, size_t nbytes)
 
   /* Is a driver registered? Does it support the write method? */
 
-  inode = this_file->f_inode;
+  inode = filep->f_inode;
   if (!inode || !inode->u.i_ops || !inode->u.i_ops->write)
     {
       err = EBADF;
@@ -92,7 +89,7 @@ static inline ssize_t file_write(int fd, FAR const void *buf, size_t nbytes)
 
   /* Yes, then let the driver perform the write */
 
-  ret = inode->u.i_ops->write(this_file, buf, nbytes);
+  ret = inode->u.i_ops->write(filep, buf, nbytes);
   if (ret < 0)
     {
       err = -ret;
diff --git a/nuttx/include/nuttx/fs/fs.h b/nuttx/include/nuttx/fs/fs.h
index c11084dee..a1678b603 100644
--- a/nuttx/include/nuttx/fs/fs.h
+++ b/nuttx/include/nuttx/fs/fs.h
@@ -594,7 +594,7 @@ struct tcb_s; /* Forward reference */
 FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb);
 #endif
 
-/* lib/stdio/lib_fflush.c **************************************************/
+/* libc/stdio/lib_fflush.c *************************************************/
 /****************************************************************************
  * Name: lib_flushall
  *
@@ -608,6 +608,49 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb);
 int lib_flushall(FAR struct streamlist *list);
 #endif
 
+/* libc/misc/lib_sendfile.c *************************************************/
+/****************************************************************************
+ * Name: lib_sendfile
+ *
+ * Description:
+ *   Transfer a file
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_SENDFILE
+ssize_t lib_sendfile(int outfd, int infd, off_t *offset, size_t count);
+#endif
+
+/* fs/fs_fileread.c *********************************************************/
+/****************************************************************************
+ * Name: file_read
+ *
+ * Description:
+ *   Equivalent to the standard read() function except that is accepts a
+ *   struct file instance instead of a file descriptor.  Currently used
+ *   only by net_sendfile()
+ *
+ ****************************************************************************/
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_NET_SENDFILE)
+ssize_t file_read(FAR struct file *filep, FAR void *buf, size_t nbytes);
+#endif
+
+/* fs/fs_fileread.c *********************************************************/
+/****************************************************************************
+ * Name: file_seek
+ *
+ * Description:
+ *   Equivalent to the standard lseek() function except that is accepts a
+ *   struct file instance instead of a file descriptor.  Currently used
+ *   only by net_sendfile()
+ *
+ ****************************************************************************/
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_NET_SENDFILE)
+off_t file_seek(FAR struct file *filep, off_t offset, int whence);
+#endif
+
 /* drivers/dev_null.c *******************************************************/
 /****************************************************************************
  * Name: devnull_register
diff --git a/nuttx/include/nuttx/net/net.h b/nuttx/include/nuttx/net/net.h
index d9ba5b9f4..402be5d5f 100644
--- a/nuttx/include/nuttx/net/net.h
+++ b/nuttx/include/nuttx/net/net.h
@@ -261,6 +261,14 @@ int net_dup2(int sockfd1, int sockfd2);
 
 int net_clone(FAR struct socket *psock1, FAR struct socket *psock2);
 
+/* net_sendfile.c ************************************************************/
+/* Send files via a TCP connections */
+
+#ifdef CONFIG_NET_SENDFILE
+struct file;
+ssize_t net_sendfile(int outfd, struct file *infile, off_t *offset, size_t count);
+#endif
+
 /* net_vfcntl.c **************************************************************/
 /* Performs fcntl operations on socket */
 
diff --git a/nuttx/include/sys/sendfile.h b/nuttx/include/sys/sendfile.h
index 0f3c05444..831c7b3d5 100644
--- a/nuttx/include/sys/sendfile.h
+++ b/nuttx/include/sys/sendfile.h
@@ -113,7 +113,7 @@ extern "C" {
  *
  ************************************************************************/
 
-EXTERN ssize_t sendfile (int outfd, int infd, FAR off_t *offset, size_t count);
+ssize_t sendfile(int outfd, int infd, FAR off_t *offset, size_t count);
 
 #undef EXTERN
 #if defined(__cplusplus)
diff --git a/nuttx/include/sys/syscall.h b/nuttx/include/sys/syscall.h
index e6d458eae..24743679a 100644
--- a/nuttx/include/sys/syscall.h
+++ b/nuttx/include/sys/syscall.h
@@ -245,9 +245,16 @@
 #  if CONFIG_NFILE_STREAMS > 0
 #    define SYS_fs_fdopen              (__SYS_filedesc+16)
 #    define SYS_sched_getstreams       (__SYS_filedesc+17)
-#    define __SYS_mountpoint           (__SYS_filedesc+18)
+#    define __SYS_sendfile             (__SYS_filedesc+18)
 #  else
-#    define __SYS_mountpoint           (__SYS_filedesc+16)
+#    define __SYS_sendfile             (__SYS_filedesc+16)
+#  endif
+
+#  if defined(CONFIG_NET_SENDFILE)
+#    define SYS_sendfile,              __SYS_sendfile
+#    define __SYS_mountpoint           (__SYS_sendfile+1)
+#  else
+#    define __SYS_mountpoint           __SYS_sendfile
 #  endif
 
 #  if !defined(CONFIG_DISABLE_MOUNTPOINT)
diff --git a/nuttx/libc/misc/lib_sendfile.c b/nuttx/libc/misc/lib_sendfile.c
index f66c30918..181fd9395 100644
--- a/nuttx/libc/misc/lib_sendfile.c
+++ b/nuttx/libc/misc/lib_sendfile.c
@@ -1,5 +1,5 @@
 /************************************************************************
- * libc/misc/lib_streamsem.c
+ * libc/misc/lib_sendfile.c
  *
  *   Copyright (C) 2007, 2009, 2011, 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
@@ -70,7 +70,7 @@
  ************************************************************************/
 
 /************************************************************************
- * Name: sendfile
+ * Name: sendfile / lib_sendfile
  *
  * Description:
  *   sendfile() copies data between one file descriptor and another.
@@ -113,7 +113,11 @@
  *
  ************************************************************************/
 
+#ifdef CONFIG_NET_SENDFILE
+ssize_t lib_sendfile(int outfd, int infd, off_t *offset, size_t count)
+#else
 ssize_t sendfile(int outfd, int infd, off_t *offset, size_t count)
+#endif
 {
   FAR uint8_t *iobuffer;
   FAR uint8_t *wrbuffer;
diff --git a/nuttx/net/Kconfig b/nuttx/net/Kconfig
index bddd9d56e..c16bbafaf 100644
--- a/nuttx/net/Kconfig
+++ b/nuttx/net/Kconfig
@@ -174,9 +174,17 @@ config NET_TCP_SPLIT_SIZE
 	---help---
 		Packets of this size or smaller than this will not be split.
 
-endif
-endif
-endmenu
+endif # NET_TCP_SPLIT
+
+config NET_SENDFILE
+	bool "Optimized network sendfile()"
+	default n
+	---help---
+		Support larger, high performance sendfile() from transferring
+		files out a TCP connection.
+
+endif # NET_TCP
+endmenu # TCP/IP Networking
 
 menu "UDP Networking"
 
diff --git a/nuttx/net/Makefile b/nuttx/net/Makefile
index 46ad34afa..234434496 100644
--- a/nuttx/net/Makefile
+++ b/nuttx/net/Makefile
@@ -68,6 +68,12 @@ ifneq ($(CONFIG_NFILE_STREAMS),0)
 SOCK_CSRCS += net_checksd.c
 endif
 
+# Support for sendfile()
+
+ifeq ($(CONFIG_NET_SENDFILE),y)
+SOCK_CSRCS += net_sendfile.c
+endif
+
 # Support for operations on network devices
 
 NETDEV_ASRCS =
diff --git a/nuttx/net/net_sendfile.c b/nuttx/net/net_sendfile.c
new file mode 100644
index 000000000..a5b2fcddf
--- /dev/null
+++ b/nuttx/net/net_sendfile.c
@@ -0,0 +1,561 @@
+/****************************************************************************
+ * net/net_sendfile.c
+ *
+ *   Copyright (C) 2013 UVC Ingenieure. All rights reserved.
+ *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
+ *   Authors: Gregory Nutt <gnutt@nuttx.org>
+ *            Max Holtzberg <mh@uvc.de>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP)
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <nuttx/clock.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/net/uip/uip-arp.h>
+#include <nuttx/net/uip/uip-arch.h>
+
+#include "net_internal.h"
+#include "uip/uip_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+#if defined(CONFIG_NET_TCP_SPLIT) && !defined(CONFIG_NET_TCP_SPLIT_SIZE)
+#  define CONFIG_NET_TCP_SPLIT_SIZE 40
+#endif
+
+#define TCPBUF ((struct uip_tcpip_hdr *)&dev->d_buf[UIP_LLH_LEN])
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/* This structure holds the state of the send operation until it can be
+ * operated upon from the interrupt level.
+ */
+
+struct sendfile_s
+{
+  FAR struct socket         *snd_sock;    /* Points to the parent socket structure */
+  FAR struct uip_callback_s *snd_datacb;  /* Data callback */
+  FAR struct uip_callback_s *snd_ackcb;   /* ACK callback */
+  FAR struct file           *snd_file;    /* File structure of the input file */
+  sem_t                      snd_sem;     /* Used to wake up the waiting thread */
+  off_t                      snd_foffset; /* Input file offset */
+  size_t                     snd_flen;    /* File length */
+  ssize_t                    snd_sent;    /* The number of bytes sent */
+  uint32_t                   snd_isn;     /* Initial sequence number */
+  uint32_t                   snd_acked;   /* The number of bytes acked */
+#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
+  uint32_t                   snd_time;    /* Last send time for determining timeout */
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: sendfile_timeout
+ *
+ * Description:
+ *   Check for send timeout.
+ *
+ * Parameters:
+ *   pstate   send state structure
+ *
+ * Returned Value:
+ *   TRUE:timeout FALSE:no timeout
+ *
+ * Assumptions:
+ *   Running at the interrupt level
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
+static inline int sendfile_timeout(FAR struct sendfile_s *pstate)
+{
+  FAR struct socket *psock = 0;
+
+  /* Check for a timeout configured via setsockopts(SO_SNDTIMEO).
+   * If none... we well let the send wait forever.
+   */
+
+  psock = pstate->snd_sock;
+  if (psock && psock->s_sndtimeo != 0)
+    {
+      /* Check if the configured timeout has elapsed */
+
+      return net_timeo(pstate->snd_time, psock->s_sndtimeo);
+    }
+
+  /* No timeout */
+
+  return FALSE;
+}
+#endif /* CONFIG_NET_SOCKOPTS && !CONFIG_DISABLE_CLOCK */
+
+static uint16_t ack_interrupt(FAR struct uip_driver_s *dev, FAR void *pvconn,
+                              FAR void *pvpriv, uint16_t flags)
+{
+  FAR struct sendfile_s *pstate = (FAR struct sendfile_s *)pvpriv;
+
+  if ((flags & UIP_ACKDATA) != 0)
+    {
+      /* The current acknowledgement number number is the (relative) offset
+       * of the of the next byte needed by the receiver.  The snd_isn is the
+       * offset of the first byte to send to the receiver.  The difference
+       * is the number of bytes to be acknowledged.
+       */
+
+      pstate->snd_acked = uip_tcpgetsequence(TCPBUF->ackno) - pstate->snd_isn;
+      nllvdbg("ACK: acked=%d sent=%d flen=%d\n",
+             pstate->snd_acked, pstate->snd_sent, pstate->snd_flen);
+
+      dev->d_sndlen = 0;
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Function: sendfile_interrupt
+ *
+ * Description:
+ *   This function is called from the interrupt level to perform the actual
+ *   send operation when polled by the uIP layer.
+ *
+ * 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
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *   Running at the interrupt level
+ *
+ ****************************************************************************/
+
+static uint16_t sendfile_interrupt(FAR struct uip_driver_s *dev, FAR void *pvconn,
+                                   FAR void *pvpriv, uint16_t flags)
+{
+  FAR struct uip_conn *conn = (FAR struct uip_conn*)pvconn;
+  FAR struct sendfile_s *pstate = (FAR struct sendfile_s *)pvpriv;
+  int ret;
+
+  nllvdbg("flags: %04x acked: %d sent: %d\n",
+          flags, pstate->snd_acked, pstate->snd_sent);
+
+  if ((flags & UIP_REXMIT) != 0)
+    {
+      /* Yes.. in this case, reset the number of bytes that have been sent
+       * to the number of bytes that have been ACKed.
+       */
+
+      pstate->snd_sent = pstate->snd_acked;
+
+      /* Fall through to re-send data from the last that was ACKed */
+    }
+
+  /* Check for a loss of connection */
+
+  else if ((flags & (UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT)) != 0)
+    {
+      /* Report not connected */
+
+      nlldbg("Lost connection\n");
+
+      net_lostconnection(pstate->snd_sock, flags);
+      pstate->snd_sent = -ENOTCONN;
+      goto end_wait;
+    }
+
+  /* We get here if (1) not all of the data has been ACKed, (2) we have been
+   * asked to retransmit data, (3) the connection is still healthy, and (4)
+   * the outgoing packet is available for our use.  In this case, we are
+   * now free to send more data to receiver -- UNLESS the buffer contains
+   * unprocessing incoming data.  In that event, we will have to wait for the
+   * next polling cycle.
+   */
+
+  if ((flags & UIP_NEWDATA) == 0 && pstate->snd_sent < pstate->snd_flen)
+    {
+      /* Get the amount of data that we can send in the next packet */
+
+      uint32_t sndlen = pstate->snd_flen - pstate->snd_sent;
+
+      if (sndlen > uip_mss(conn))
+        {
+          sndlen = uip_mss(conn);
+        }
+
+      /* Check if we have "space" in the window */
+#warning REVISIT
+#if 0 /* Where is wndsize defined? */
+      if ((pstate->snd_sent - pstate->snd_acked + sndlen) < conn->wndsize)
+#endif
+        {
+          uint32_t seqno;
+
+          /* Then set-up to send that amount of data. (this won't actually
+           * happen until the polling cycle completes).
+           */
+
+          ret = file_seek(pstate->snd_file,
+                          pstate->snd_foffset + pstate->snd_sent, SEEK_SET);
+          if (ret < 0)
+            {
+              int errcode = errno;
+              nlldbg("failed to lseek: %d\n", errcode);
+              pstate->snd_sent = -errcode;
+              goto end_wait;
+            }
+
+          ret = file_read(pstate->snd_file, dev->d_snddata, sndlen);
+          if (ret < 0)
+            {
+              int errcode = errno;
+              nlldbg("failed to read from input file: %d\n", errcode);
+              pstate->snd_sent = -errcode;
+              goto end_wait;
+            }
+
+          dev->d_sndlen = sndlen;
+
+          /* Set the sequence number for this packet.  NOTE:  uIP updates
+           * sndseq on recept of ACK *before* this function is called.  In that
+           * case sndseq will point to the next unacknowledge byte (which might
+           * have already been sent).  We will overwrite the value of sndseq
+           * here before the packet is sent.
+           */
+
+          seqno = pstate->snd_sent + pstate->snd_isn;
+          nllvdbg("SEND: sndseq %08x->%08x len: %d\n", conn->sndseq, seqno, ret);
+
+          uip_tcpsetsequence(conn->sndseq, seqno);
+
+          /* Check if the destination IP address is in the ARP table.  If not,
+           * then the send won't actually make it out... it will be replaced with
+           * an ARP request.
+           *
+           * NOTE 1: This could be an expensive check if there are a lot of entries
+           * in the ARP table.  Hence, we only check on the first packet -- when
+           * snd_sent is zero.
+           *
+           * NOTE 2: If we are actually harvesting IP addresses on incomming IP
+           * packets, then this check should not be necessary; the MAC mapping
+           * should already be in the ARP table.
+           */
+
+#if defined(CONFIG_NET_ETHERNET) && !defined (CONFIG_NET_ARP_IPIN)
+          if (pstate->snd_sent != 0 || uip_arp_find(conn->ripaddr) != NULL)
+#endif
+            {
+              /* Update the amount of data sent (but not necessarily ACKed) */
+
+              pstate->snd_sent += sndlen;
+              nllvdbg("pid: %d SEND: acked=%d sent=%d flen=%d\n", getpid(),
+                     pstate->snd_acked, pstate->snd_sent, pstate->snd_flen);
+
+              /* Update the send time */
+
+#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
+              pstate->snd_time = clock_systimer();
+#endif
+            }
+        }
+#warning REVISIT
+#if 0 /* Where is wndsize defined? */
+      else
+        {
+          nlldbg("window full, wait for ack\n");
+          goto wait;
+        }
+#endif
+    }
+
+  /* All data has been send and we are just waiting for ACK or re-transmit
+   * indications to complete the send.  Check for a timeout.
+   */
+
+#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
+  else if (sendfile_timeout(pstate))
+    {
+      /* Yes.. report the timeout */
+
+      nlldbg("SEND timeout\n");
+      pstate->snd_sent = -ETIMEDOUT;
+      goto end_wait;
+    }
+#endif /* CONFIG_NET_SOCKOPTS && !CONFIG_DISABLE_CLOCK */
+
+end_wait:
+
+  /* Do not allow any further callbacks */
+
+  pstate->snd_datacb->flags   = 0;
+  pstate->snd_datacb->priv    = NULL;
+  pstate->snd_datacb->event   = NULL;
+
+  /* Wake up the waiting thread */
+
+  sem_post(&pstate->snd_sem);
+
+wait:
+  return flags;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: net_sendfile
+ *
+ * Description:
+ *   The send() call may be used only when the socket is in a connected state
+ *   (so that the intended recipient is known). The only difference between
+ *   send() and write() is the presence of flags. With zero flags parameter,
+ *   send() is equivalent to write(). Also, send(sockfd,buf,len,flags) is
+ *   equivalent to sendto(sockfd,buf,len,flags,NULL,0).
+ *
+ * Parameters:
+ *   psock    An instance of the internal socket structure.
+ *   buf      Data to send
+ *   len      Length of data to send
+ *   flags    Send flags
+ *
+ * Returned Value:
+ *   On success, returns the number of characters sent.  On  error,
+ *   -1 is returned, and errno is set appropriately:
+ *
+ *   EAGAIN or EWOULDBLOCK
+ *     The socket is marked non-blocking and the requested operation
+ *     would block.
+ *   EBADF
+ *     An invalid descriptor was specified.
+ *   ECONNRESET
+ *     Connection reset by peer.
+ *   EDESTADDRREQ
+ *     The socket is not connection-mode, and no peer address is set.
+ *   EFAULT
+ *      An invalid user space address was specified for a parameter.
+ *   EINTR
+ *      A signal occurred before any data was transmitted.
+ *   EINVAL
+ *      Invalid argument passed.
+ *   EISCONN
+ *     The connection-mode socket was connected already but a recipient
+ *     was specified. (Now either this error is returned, or the recipient
+ *     specification is ignored.)
+ *   EMSGSIZE
+ *     The socket type requires that message be sent atomically, and the
+ *     size of the message to be sent made this impossible.
+ *   ENOBUFS
+ *     The output queue for a network interface was full. This generally
+ *     indicates that the interface has stopped sending, but may be
+ *     caused by transient congestion.
+ *   ENOMEM
+ *     No memory available.
+ *   ENOTCONN
+ *     The socket is not connected, and no target has been given.
+ *   ENOTSOCK
+ *     The argument s is not a socket.
+ *   EOPNOTSUPP
+ *     Some bit in the flags argument is inappropriate for the socket
+ *     type.
+ *   EPIPE
+ *     The local end has been shut down on a connection oriented socket.
+ *     In this case the process will also receive a SIGPIPE unless
+ *     MSG_NOSIGNAL is set.
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+ssize_t net_sendfile(int outfd, struct file *infile, off_t *offset,
+                     size_t count)
+{
+  FAR struct socket *psock = sockfd_socket(outfd);
+  FAR struct uip_conn *conn = (FAR struct uip_conn*)psock->s_conn;
+  struct sendfile_s state;
+  uip_lock_t save;
+  int err;
+
+  nlldbg("pid: %d\n", getpid());
+
+  /* Verify that the sockfd corresponds to valid, allocated socket */
+
+  if (!psock || psock->s_crefs <= 0)
+    {
+      err = EBADF;
+      goto errout;
+    }
+
+  /* If this is an un-connected socket, then return ENOTCONN */
+
+  if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(psock->s_flags))
+    {
+      err = ENOTCONN;
+      goto errout;
+    }
+
+  /* Set the socket state to sending */
+
+  psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
+
+  /* Initialize the state structure.  This is done with interrupts
+   * disabled because we don't want anything to happen until we
+   * are ready.
+   */
+
+  save  = uip_lock();
+
+  memset(&state, 0, sizeof(struct sendfile_s));
+  sem_init(&state. snd_sem, 0, 0);          /* Doesn't really fail */
+  state.snd_sock    = psock;                /* Socket descriptor to use */
+  state.snd_foffset = offset ? *offset : 0; /* Input file offset */
+  state.snd_flen    = count;                /* Number of bytes to send */
+  state.snd_file    = infile;               /* File to read from */
+
+  /* Allocate resources to receive a callback */
+
+  state.snd_datacb = uip_tcpcallbackalloc(conn);
+
+  if (state.snd_datacb == NULL)
+    {
+      nlldbg("Failed to allocate data callback\n");
+      err = ENOMEM;
+      goto errout_locked;
+    }
+
+  state.snd_ackcb = uip_tcpcallbackalloc(conn);
+
+  if (state.snd_ackcb == NULL)
+    {
+      nlldbg("Failed to allocate ack callback\n");
+      err = ENOMEM;
+      goto errout_datacb;
+    }
+
+  /* Get the initial sequence number that will be used */
+
+  state.snd_isn         = uip_tcpgetsequence(conn->sndseq);
+
+  /* There is no outstanding, unacknowledged data after this
+   * initial sequence number.
+   */
+
+  conn->unacked         = 0;
+
+  /* Set the initial time for calculating timeouts */
+
+#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
+  state.snd_time        = clock_systimer();
+#endif
+
+  /* Set up the ACK callback in the connection */
+
+  state.snd_ackcb->flags   = UIP_ACKDATA;
+  state.snd_ackcb->priv    = (void*)&state;
+  state.snd_ackcb->event   = ack_interrupt;
+
+  /* Perform the TCP send operation */
+
+  do
+    {
+      state.snd_datacb->flags   = UIP_REXMIT|UIP_POLL|UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT;
+      state.snd_datacb->priv    = (void*)&state;
+      state.snd_datacb->event   = sendfile_interrupt;
+
+      /* Notify the device driver of the availaibilty of TX data */
+
+      netdev_txnotify(&conn->ripaddr);
+
+      uip_lockedwait(&state.snd_sem);
+    }
+  while (state.snd_sent > 0 && state.snd_acked < state.snd_flen);
+
+  /* Set the socket state to idle */
+
+  psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
+
+  uip_tcpcallbackfree(conn, state.snd_ackcb);
+
+ errout_datacb:
+  uip_tcpcallbackfree(conn, state.snd_datacb);
+
+ errout_locked:
+
+  sem_destroy(&state. snd_sem);
+  uip_unlock(save);
+
+ errout:
+
+  if (err)
+    {
+      set_errno(err);
+      return ERROR;
+    }
+  else if (state.snd_sent < 0)
+    {
+      set_errno(-state.snd_sent);
+      return ERROR;
+    }
+  else
+    {
+      return state.snd_sent;
+    }
+}
+
+#endif /* CONFIG_NET && CONFIG_NET_TCP */
diff --git a/nuttx/net/send.c b/nuttx/net/send.c
index 2d66f26f0..3d18ecde5 100644
--- a/nuttx/net/send.c
+++ b/nuttx/net/send.c
@@ -51,6 +51,7 @@
 
 #include <arch/irq.h>
 #include <nuttx/clock.h>
+#include <nuttx/net/uip/uip-arp.h>
 #include <nuttx/net/uip/uip-arch.h>
 
 #ifdef CONFIG_NET_ARP_IPIN
diff --git a/nuttx/syscall/syscall.csv b/nuttx/syscall/syscall.csv
index 71d800950..e470b91a7 100644
--- a/nuttx/syscall/syscall.csv
+++ b/nuttx/syscall/syscall.csv
@@ -106,6 +106,7 @@
 "sem_unlink","semaphore.h","","int","FAR const char*"
 "sem_wait","semaphore.h","","int","FAR sem_t*"
 "send","sys/socket.h","CONFIG_NSOCKET_DESCRIPTORS > 0 && defined(CONFIG_NET)","ssize_t","int","FAR const void*","size_t","int"
+"sendfile","sys/sendfile.h","CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_NET_SENDFILE)","ssize_t","int","int","FAR off_t*","size_t"
 "sendto","sys/socket.h","CONFIG_NSOCKET_DESCRIPTORS > 0 && defined(CONFIG_NET)","ssize_t","int","FAR const void*","size_t","int","FAR const struct sockaddr*","socklen_t"
 "set_errno","errno.h","","void","int"
 "setenv","stdlib.h","!defined(CONFIG_DISABLE_ENVIRON)","int","const char*","const char*","int"
diff --git a/nuttx/syscall/syscall_lookup.h b/nuttx/syscall/syscall_lookup.h
index d87385f0a..b370bdd5b 100644
--- a/nuttx/syscall/syscall_lookup.h
+++ b/nuttx/syscall/syscall_lookup.h
@@ -182,7 +182,11 @@ SYSCALL_LOOKUP(up_assert,                 2, STUB_up_assert)
 #  if CONFIG_NFILE_STREAMS > 0
   SYSCALL_LOOKUP(fdopen,                  3, STUB_fs_fdopen)
   SYSCALL_LOOKUP(sched_getstreams,        0, STUB_sched_getstreams)
-#endif
+#  endif
+
+#  if defined(CONFIG_NET_SENDFILE)
+  SYSCALL_LOOKUP(sendfile,                4, STUB_fs_sendifile)
+#  endif
 
 #  if !defined(CONFIG_DISABLE_MOUNTPOINT)
   SYSCALL_LOOKUP(fsync,                   1, STUB_fsync)
diff --git a/nuttx/syscall/syscall_stublookup.c b/nuttx/syscall/syscall_stublookup.c
index 517c15af3..436637c9e 100644
--- a/nuttx/syscall/syscall_stublookup.c
+++ b/nuttx/syscall/syscall_stublookup.c
@@ -199,6 +199,8 @@ uintptr_t STUB_fs_fdopen(int nbr, uintptr_t parm1, uintptr_t parm2,
             uintptr_t parm3);
 uintptr_t STUB_sched_getstreams(int nbr);
 
+ssize_t sendfile(int outfd, int infd, FAR off_t *offset, size_t count);
+
 uintptr_t STUB_fsync(int nbr, uintptr_t parm1);
 uintptr_t STUB_mkdir(int nbr, uintptr_t parm1, uintptr_t parm2);
 uintptr_t STUB_mount(int nbr, uintptr_t parm1, uintptr_t parm2,