Squashed commit of the following:

syscalls/:  Add syscall support for if_nametoindex() and if_indextoname()
    net/: Update some comments.

net/netdev/netdev_count.c

@@ -64,9 +64,6 @@
  * Returned Value:
  *   The number of network devices
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 int netdev_count(void)

net/netdev/netdev_default.c

@@ -68,9 +68,6 @@
  * Returned Value:
  *  Pointer to default network driver on success; null on failure
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 FAR struct net_driver_s *netdev_default(void)

net/netdev/netdev_findbyaddr.c

@@ -74,9 +74,6 @@
  * Returned Value:
  *  Pointer to driver on success; null on failure
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv4
@@ -127,9 +124,6 @@ static FAR struct net_driver_s *netdev_finddevice_ipv4addr(in_addr_t ripaddr)
  * Returned Value:
  *  Pointer to driver on success; null on failure
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv6
@@ -185,9 +179,6 @@ netdev_finddevice_ipv6addr(const net_ipv6addr_t ripaddr)
  * Returned Value:
  *  Pointer to driver on success; null on failure
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv4
@@ -285,9 +276,6 @@ FAR struct net_driver_s *netdev_findby_ipv4addr(in_addr_t lipaddr,
  * Returned Value:
  *  Pointer to driver on success; null on failure
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv6

net/netdev/netdev_findbyname.c

@@ -65,9 +65,6 @@
  * Returned Value:
  *  Pointer to driver on success; null on failure
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 FAR struct net_driver_s *netdev_findbyname(FAR const char *ifname)

net/netdev/netdev_indextoname.c

@@ -0,0 +1,134 @@
+/****************************************************************************
+ * net/netdev/netdev_indextoname.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 <string.h>
+#include <assert.h>
+#include <errno.h>
+
+#include <net/if.h>
+
+#include "nuttx/net/net.h"
+#include "nuttx/net/netdev.h"
+
+#include "netdev/netdev.h"
+
+#ifdef CONFIG_NETDEV_IFINDEX
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: netdev_indextoname
+ *
+ * Description:
+ *   The if_indextoname() function maps an interface index to its
+ *   corresponding name.
+ *
+ * Input Parameters:
+ *   ifname  - Points to a buffer of at least IF_NAMESIZE bytes.
+ *             if_indextoname() will place in this buffer the name of the
+ *             interface with index ifindex.
+ *
+ * Returned Value:
+ *   If ifindex is an interface index, then the function will return zero
+ *   (OK). Otherwise, the function returns a negated errno value;
+ *
+ ****************************************************************************/
+
+int netdev_indextoname(unsigned int ifindex, FAR char *ifname)
+{
+  FAR struct net_driver_s *dev;
+  int ret = -ENODEV;
+
+  DEBUGASSERT(ifindex > 0 && ifindex <= MAX_IFINDEX);
+  DEBUGASSERT(ifname != NULL);
+
+  /* Find the driver with this name */
+
+  net_lock();
+  dev = netdev_findbyindex(ifindex);
+  if (dev != NULL)
+    {
+      memcpy(ifname, dev->d_ifname, IF_NAMESIZE);
+      ret = OK;
+    }
+
+  net_unlock();
+  return ret;
+}
+
+/****************************************************************************
+ * Name: if_indextoname
+ *
+ * Description:
+ *   The if_indextoname() function maps an interface index to its
+ *   corresponding name.
+ *
+ * Input Parameters:
+ *   ifname  - Points to a buffer of at least IF_NAMESIZE bytes.
+ *             if_indextoname() will place in this buffer the name of the
+ *             interface with index ifindex.
+ *
+ * Returned Value:
+ *   If ifindex is an interface index, then the function will return the
+ *   value supplied by ifname. Otherwise, the function returns a NULL pointer
+ *   and sets errno to indicate the error.
+ *
+ ****************************************************************************/
+
+FAR char *if_indextoname(unsigned int ifindex, FAR char *ifname)
+{
+  int ret;
+
+  /* Let netdev_indextoname to the work */
+
+  ret = netdev_indextoname(ifindex, ifname);
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      return NULL;
+    }
+
+  return ifname;
+}
+
+#endif /* CONFIG_NETDEV_IFINDEX */

net/netdev/netdev_nametoindex.c

@@ -0,0 +1,124 @@
+/****************************************************************************
+ * net/netdev/netdev_nametoindex.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 <assert.h>
+#include <errno.h>
+
+#include <net/if.h>
+
+#include "nuttx/net/net.h"
+#include "nuttx/net/netdev.h"
+
+#include "netdev/netdev.h"
+
+#ifdef CONFIG_NETDEV_IFINDEX
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: netdev_nametoindex
+ *
+ * Description:
+ *   The if_nametoindex() function returns the interface index corresponding
+ *   to name ifname.
+ *
+ * Input Parameters:
+ *   ifname - The interface name
+ *
+ * Returned Value:
+ *   The corresponding index if ifname is the name of an interface;
+ *   otherwise, a negated errno value is returned.
+ *
+ ****************************************************************************/
+
+unsigned int netdev_nametoindex(FAR const char *ifname)
+{
+  FAR struct net_driver_s *dev;
+  unsigned int ifindex = -ENODEV;
+
+  /* Find the driver with this name */
+
+  net_lock();
+  dev = netdev_findbyname(ifname);
+  if (dev != NULL)
+    {
+      ifindex = dev->d_ifindex;
+    }
+
+  net_unlock();
+  return ifindex;
+}
+
+/****************************************************************************
+ * Name: if_nametoindex
+ *
+ * Description:
+ *   The if_nametoindex() function returns the interface index corresponding
+ *   to name ifname.
+ *
+ * Input Parameters:
+ *   ifname - The interface name
+ *
+ * Returned Value:
+ *   The corresponding index if ifname is the name of an interface;
+ *   otherwise, zero.  Although not specified, the errno value will be set.
+ *
+ ****************************************************************************/
+
+unsigned int if_nametoindex(FAR const char *ifname)
+{
+  int ret;
+
+  /* Let netdev_nametoindex to the work */
+
+  ret = netdev_nametoindex(ifname);
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      return 0;
+    }
+
+  return ret;
+}
+
+#endif /* CONFIG_NETDEV_IFINDEX */

net/netdev/netdev_register.c

@@ -221,7 +221,8 @@ static int get_ifindex(void)
  *   0:Success; negated errno on failure
  *
  * Assumptions:
- *   Called during system initialization from normal user mode
+ *   Called during system bring-up, but also when a removable network
+ *   device is installed.
  *
  ****************************************************************************/
 

net/netdev/netdev_txnotify.c

@@ -68,9 +68,6 @@
  * Returned Value:
  *  None
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv4
@@ -105,9 +102,6 @@ void netdev_ipv4_txnotify(in_addr_t lipaddr, in_addr_t ripaddr)
  * Returned Value:
  *  None
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv6
@@ -142,9 +136,6 @@ void netdev_ipv6_txnotify(FAR const net_ipv6addr_t lipaddr,
  * Returned Value:
  *  None
  *
- * Assumptions:
- *  Called from normal user mode
- *
  ****************************************************************************/
 
 void netdev_txnotify_dev(FAR struct net_driver_s *dev)

net/socket/setsockopt.c

@@ -53,6 +53,7 @@
 
 #include "socket/socket.h"
 #include "tcp/tcp.h"
+#include "udp/udp.h"
 #include "usrsock/usrsock.h"
 #include "utils/utils.h"
 
@@ -369,13 +370,18 @@ int psock_setsockopt(FAR struct socket *psock, int level, int option,
        break;
 #endif
 
+      case SOL_UDP:    /* UDP protocol socket options (see include/netinet/udp.h) */
+#ifdef CONFIG_NET_UDPPROTO_OPTIONS
+       ret = udp_setsockopt(psock, option, value, value_len);
+       break;
+#endif
+
       /* These levels are defined in sys/socket.h, but are not yet
        * implemented.
        */
 
       case SOL_IP:     /* TCP protocol socket options (see include/netinet/ip.h) */
       case SOL_IPV6:   /* TCP protocol socket options (see include/netinet/ip6.h) */
-      case SOL_UDP:    /* TCP protocol socket options (see include/netinit/udp.h) */
         ret = -ENOSYS;
        break;
 

net/tcp/tcp.h

@@ -331,7 +331,7 @@ struct pollfd;    /* Forward reference */
  *
  * Description:
  *   Initialize the TCP/IP connection structures.  Called only once and only
- *   from the UIP layer at start-up in normal user mode.
+ *   from the network layer at start-up.
  *
  ****************************************************************************/
 

net/tcp/tcp_conn.c

@@ -581,7 +581,7 @@ static inline int tcp_ipv6_bind(FAR struct tcp_conn_s *conn,
  *
  * Description:
  *   Initialize the TCP/IP connection structures.  Called only once and only
- *   from the UIP layer at start-up in normal user mode.
+ *   from the network layer at start-up.
  *
  ****************************************************************************/
 

net/udp/Kconfig

@@ -21,6 +21,15 @@ config NET_UDP_NO_STACK
 
 if NET_UDP && !NET_UDP_NO_STACK
 
+config NET_UDP_BINDTODEVICE
+	bool "UDP Bind-to-device support"
+	default n
+	select NET_UDPPROTO_OPTIONS
+	---help---
+		Enable support for the UDP_BINDTODEVICE socket option.
+		Linux has SO_BINDTODEVICE but in NuttX this option is instead
+		specific to the UDP protocol.
+
 config NET_UDP_CHECKSUMS
 	bool "UDP checksums"
 	default y if NET_IPv6

net/udp/Make.defs

@@ -42,6 +42,10 @@ ifneq ($(CONFIG_NET_UDP_NO_STACK),y)
 
 SOCK_CSRCS += udp_psock_send.c
 
+ifeq ($(CONFIG_NET_UDPPROTO_OPTIONS),y)
+SOCK_CSRCS += udp_setsockopt.c
+endif
+
 ifeq ($(CONFIG_NET_UDP_WRITE_BUFFERS),y)
 SOCK_CSRCS += udp_psock_sendto_buffered.c
 else

net/udp/udp.h

@@ -345,6 +345,35 @@ void udp_poll(FAR struct net_driver_s *dev, FAR struct udp_conn_s *conn);
 
 void udp_send(FAR struct net_driver_s *dev, FAR struct udp_conn_s *conn);
 
+/****************************************************************************
+ * Name: udp_setsockopt
+ *
+ * Description:
+ *   udp_setsockopt() sets the UDP-protocol option specified by the
+ *   'option' argument to the value pointed to by the 'value' argument for
+ *   the socket specified by the 'psock' argument.
+ *
+ *   See <netinet/udp.h> for the a complete list of values of UDP protocol
+ *   options.
+ *
+ * Input Parameters:
+ *   psock     Socket structure of socket to operate on
+ *   option    identifies the option to set
+ *   value     Points to the argument value
+ *   value_len The length of the argument value
+ *
+ * Returned Value:
+ *   Returns zero (OK) on success.  On failure, it returns a negated errno
+ *   value to indicate the nature of the error.  See psock_setcockopt() for
+ *   the list of possible error values.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_UDPPROTO_OPTIONS
+int udp_setsockopt(FAR struct socket *psock, int option,
+                   FAR const void *value, socklen_t value_len);
+#endif
+
 /****************************************************************************
  * Name: udp_wrbuffer_initialize
  *

net/udp/udp_setsockopt.c

@@ -0,0 +1,141 @@
+/****************************************************************************
+ * net/udp/udp_setsockopt.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/time.h>
+#include <stdint.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <netinet/udp.h>
+
+#include <nuttx/clock.h>
+#include <nuttx/net/net.h>
+#include <nuttx/net/udp.h>
+
+#include "socket/socket.h"
+#include "utils/utils.h"
+#include "udp/udp.h"
+
+#ifdef CONFIG_NET_UDPPROTO_OPTIONS
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: udp_setsockopt
+ *
+ * Description:
+ *   udp_setsockopt() sets the UDP-protocol option specified by the
+ *   'option' argument to the value pointed to by the 'value' argument for
+ *   the socket specified by the 'psock' argument.
+ *
+ *   See <netinet/udp.h> for the a complete list of values of UDP protocol
+ *   options.
+ *
+ * Input Parameters:
+ *   psock     Socket structure of socket to operate on
+ *   option    identifies the option to set
+ *   value     Points to the argument value
+ *   value_len The length of the argument value
+ *
+ * Returned Value:
+ *   Returns zero (OK) on success.  On failure, it returns a negated errno
+ *   value to indicate the nature of the error.  See psock_setcockopt() for
+ *   the list of possible error values.
+ *
+ ****************************************************************************/
+
+int udp_setsockopt(FAR struct socket *psock, int option,
+                   FAR const void *value, socklen_t value_len)
+{
+#ifdef CONFIG_NET_UDP_BINDTODEVICE
+  /* Keep alive options are the only UDP protocol socket option currently
+   * supported.
+   */
+
+  FAR struct udp_conn_s *conn;
+  int ret;
+
+  DEBUGASSERT(psock != NULL && value != NULL && psock->s_conn != NULL);
+  conn = (FAR struct udp_conn_s *)psock->s_conn;
+
+  /* All of the UDP protocol options apply only UDP sockets.  The sockets
+   * do not have to be connected.. that might occur later with the KeepAlive
+   * already configured.
+   */
+
+  if (psock->s_type != SOCK_STREAM)
+    {
+      nerr("ERROR:  Not a UDP socket\n");
+      return -ENOTCONN;
+    }
+
+  /* Handle the Keep-Alive option */
+
+  switch (option)
+    {
+      /* Handle the SO_KEEPALIVE socket-level option.
+       *
+       * NOTE: SO_KEEPALIVE is not really a socket-level option; it is a
+       * protocol-level option.  A given UDP connection may service multiple
+       * sockets (via dup'ing of the socket).  There is, however, still only
+       * one connection to be monitored and that is a global attribute across
+       * all of the clones that may use the underlying connection.
+       */
+
+      case UDP_BINDTODEVICE:  /* Bind socket to a specific network device */
+        break;
+
+      default:
+        nerr("ERROR: Unrecognized UDP option: %d\n", option);
+        ret = -ENOPROTOOPT;
+        break;
+    }
+
+  return ret;
+#else
+  return -ENOPROTOOPT;
+#endif /* CONFIG_NET_UDP_BINDTODEVICE */
+}
+
+#endif /* CONFIG_NET_UDPPROTO_OPTIONS */