fs/vfs and net/udp: Repartition logic of commit 0c963449d6, moving into net/udp. Add support to handle connected UDP sockets. The correct 'optimal blksize' to return is the MSS. The MTU is always too big.

2026-09-27 18:58:27 +08:00 · 2018-04-27 08:36:25 -06:00
parent c881ea6d5b
commit f5d0fc7447
5 changed files with 227 additions and 22 deletions
@@ -1,7 +1,7 @@
 ############################################################################
 # net/socket/Make.defs
 #
-#   Copyright (C) 2014-2015, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2014-2015, 2017, 2018 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -38,6 +38,7 @@
 SOCK_CSRCS += bind.c connect.c getsockname.c recv.c recvfrom.c send.c
 SOCK_CSRCS += sendto.c socket.c net_sockets.c net_close.c net_dupsd.c
 SOCK_CSRCS += net_dupsd2.c net_sockif.c net_clone.c net_poll.c net_vfcntl.c
+SOCK_CSRCS += net_fstat.c

 # TCP/IP support

@@ -0,0 +1,190 @@
+/****************************************************************************
+ * net/socket/net_fstat.c
+ *
+ *   Copyright (C) 2018 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/stat.h>
+#include <string.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/net/netconfig.h>
+#include <nuttx/net/net.h>
+#include <nuttx/net/netdev.h>
+
+#include "tcp/tcp.h"
+#include "udp/udp.h"
+#include "socket/socket.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: net_fstat
+ *
+ * Description:
+ *   Performs fstat operations on socket
+ *
+ * Input Parameters:
+ *   sockfd - Socket descriptor of the socket to operate on
+ *   bug    - Caller-provided location in which to return the fstat data
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int net_fstat(int sockfd, FAR struct stat *buf)
+{
+  FAR struct socket *psock;
+  int ret = OK;
+
+  /* Get the underlying socket structure */
+
+  psock = sockfd_socket(sockfd);
+  if (psock == NULL)
+    {
+      /* sockfd does not refer to a valid, open socket */
+
+      return -EBADF;
+    }
+
+  /* Return fstat data.  The st_mode and st_blksize fields are the only
+   * fields set for socket descriptors.  The st_mode field is set to a value
+   * that indicates the descriptor is a socket descriptor and the st_blksize
+   * field is set to an optimal value determined by the system.  The optimal
+   * packet size is the MSS.
+   */
+
+  memset(buf, 0, sizeof(struct stat));
+  buf->st_mode = S_IFSOCK;
+
+  /* The socket must be open and in a connected state in order to get the
+   * MSS.  There may be multiple networks served by different network
+   * devices, each supporting a different MSS.
+   */
+
+  if (psock->s_conn == NULL || !_SS_ISCONNECTED(psock->s_flags))
+    {
+      /* Not connected.. Return an optimal blocksize of zero (or, perhaps,
+       * even an error?)
+       *
+       * REVISIT:  The concept of connected only applies to TCP and UDP
+       * sockets.  Other sockets, such raw radio sockets, have no such
+       * concept.
+       */
+
+      nwarn("WARNING:  Socket not connected\n");
+      return OK;
+    }
+
+  /* We are only prepared to handle the MSS of connected TCP/IP and UDP
+   * sockets here.
+   */
+
+  switch (psock->s_type)
+    {
+#if defined(NET_TCP_HAVE_STACK)
+       case SOCK_STREAM:
+         {
+           FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)psock->s_conn;
+
+           /* For TCP, the MSS is a dynamic value that maintained in the
+            * connection structure.
+            */
+
+           buf->st_blksize = conn->mss;
+         }
+         break;
+#endif
+
+#if defined(NET_UDP_HAVE_STACK)
+       case SOCK_DGRAM:
+         {
+           FAR struct udp_conn_s *conn = (FAR struct udp_conn_s *)psock->s_conn;
+           FAR struct net_driver_s *dev;
+           uint16_t iplen;
+
+           /* For a connected UDP socket, we have do do a little more work:
+            *
+            *   MSS = MTU - LL_HDRLEN - UDP_HDRLEN - IP_HDRLEN
+            *
+            * We need to have the device that services the connection in order
+            * to get the MTU and LL_HDRLEN:
+            */
+
+           dev = udp_find_raddr_device(conn);
+           if (dev == NULL)
+             {
+               /* This should never happen except perhaps in some rare race
+                * condition.  If the UDP socket is connected, then the device
+                * service the network that it is connected to should always
+                * exist.
+                */
+
+               nerr("ERROR:  Could not find network device\n");
+               ret = -ENODEV;
+             }
+           else
+             {
+               /* We need the length of the IP header */
+
+#if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6)
+               iplen = (conn->domain == PF_INET) ? IPv4_HDRLEN : IPv6_HDRLEN
+#elif defined(CONFIG_NET_IPv4)
+               iplen = IPv4_HDRLEN;
+#else
+               iplen = IPv6_HDRLEN;
+#endif
+               /* Now we can calculate the MSS */
+
+               buf->st_blksize = UDP_MSS(dev, iplen);
+             }
+         }
+         break;
+#endif
+       default:
+         nwarn("WARNING:  Unhandled socket type: %u\n", psock->s_type);
+         break;
+     }
+
+   return ret;
+}