Add an 'arp' command to NSH to support access to the OS ARP table

ChangeLog.txt

@@ -1548,4 +1548,6 @@
 	* apps/netutils/dhcpd: DHCPD no longer calls directly into the
 	  OS but uses the new network IOCTL commands to modify the ARP
 	  table (2016-02-08).
+	* apps/nshlib:  Add an 'arp' command that will support access to
+	  the OS ARP table (2016-02-08).
 

netutils/netlib/netlib_setarp.c

@@ -89,7 +89,7 @@ int netlib_set_arpmapping(FAR const struct sockaddr_in *inaddr,
           memcpy(&req.arp_pa, inaddr, sizeof(struct sockaddr_in));
 
           req.arp_ha.sa_family = ARPHRD_ETHER;
-          memcpy(&req.arp_ha, macaddr,ETHER_ADDR_LEN);
+          memcpy(&req.arp_ha.sa_data, macaddr, ETHER_ADDR_LEN);
 
           ret = ioctl(sockfd, SIOCSARP, (unsigned long)((uintptr_t)&req));
           if (ret < 0)

nshlib/Kconfig

@@ -195,6 +195,12 @@ config NSH_DISABLE_ADDROUTE
 	default y if DEFAULT_SMALL
 	default n if !DEFAULT_SMALL
 
+config NSH_DISABLE_ARP
+	bool "Disable arp"
+	default y if DEFAULT_SMALL
+	default n if !DEFAULT_SMALL
+	depends on NET_ARP
+
 config NSH_DISABLE_BASE64DEC
 	bool "Disable base64dec"
 	default y if DEFAULT_SMALL

nshlib/README.txt

@@ -297,6 +297,33 @@ o addroute <target> <netmask> <router>
 
     nsh> addroute 1.1.1.1 2.2.2.2 3.3.3.3
 
+o arp [-a <ipaddr>|-d <ipaddr>|-s <ipaddr> <hwaddr>]
+
+  Access the OS ARP table.
+
+  -a <ipaddr>
+     Will show the hardware address that the IP address <ipaddr> is mapped to.
+
+  -d <ipaddr>
+     Will delete the mapping for the IP address <ipaddr> from the ARP table
+
+  -s <ipaddr> <hwaddr>
+     Will set (or replace) the mapping of the IP address <ipaddr> to the
+     hardware address <hwaddr>
+
+  Example:
+
+    nsh> arp -a 10.0.0.1
+    nsh: arp: ioctl failed: 22
+
+    nsh> arp -s 10.0.0.1 00:13:3b:12:73:e6
+    nsh> arp -a 10.0.0.1
+    HWAddr: 00:13:3b:12:73:e6
+
+    nsh> arp -d 10.0.0.1
+    nsh> arp -a 10.0.0.1
+    nsh: arp: ioctl failed: 22
+
 o base64dec [-w] [-f] <string or filepath>
 
 o base64dec [-w] [-f] <string or filepath>
@@ -1143,6 +1170,7 @@ Command Dependencies on Configuration Settings
   ---------- --------------------------
   [          !CONFIG_NSH_DISABLESCRIPT
   addroute   CONFIG_NET && CONFIG_NET_ROUTE
+  arp        CONFIG_NET && CONFIG_NET_ARP
   base64dec  CONFIG_NETUTILS_CODECS && CONFIG_CODECS_BASE64
   base64enc  CONFIG_NETUTILS_CODECS && CONFIG_CODECS_BASE64
   basename   --

nshlib/nsh.h

@@ -1092,6 +1092,9 @@ int cmd_lsmod(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #endif /* CONFIG_NFILE_DESCRIPTORS */
 
 #if defined(CONFIG_NET)
+#  if defined(CONFIG_NET_ARP) && !defined(CONFIG_NSH_DISABLE_ARP)
+      int cmd_arp(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#  endif
 #  if defined(CONFIG_NET_ROUTE) && !defined(CONFIG_NSH_DISABLE_ADDROUTE)
       int cmd_addroute(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #  endif

nshlib/nsh_command.c

@@ -114,6 +114,10 @@ static const struct cmdmap_s g_cmdmap[] =
   { "addroute", cmd_addroute, 4, 4, "<target> <netmask> <router>" },
 #endif
 
+#if defined(CONFIG_NET) && defined(CONFIG_NET_ARP) && !defined(CONFIG_NSH_DISABLE_ARP)
+  { "arp",      cmd_arp,      3, 4, "[-a <ipaddr>|-d <ipaddr>|-s <ipaddr> <hwaddr>]" },
+#endif
+
 #if defined(CONFIG_NETUTILS_CODECS) && defined(CONFIG_CODECS_BASE64)
 #  ifndef CONFIG_NSH_DISABLE_BASE64DEC
   { "base64dec", cmd_base64decode, 2, 4, "[-w] [-f] <string or filepath>" },

nshlib/nsh_netcmds.c

@@ -628,6 +628,36 @@ static int nsh_foreach_netdev(nsh_netdev_callback_t callback,
 }
 #endif
 
+/****************************************************************************
+ * Name: cmd_get
+ ****************************************************************************/
+#if defined(CONFIG_NET_ARP) && !defined(CONFIG_NSH_DISABLE_ARP)
+int mac_nibble(unsigned int ch, unsigned int *nibble)
+{
+  unsigned int ret;
+
+  if (ch >= '0' && ch <= '9')
+    {
+      ret = ch - '0';
+    }
+  else if (ch >= 'A' && ch <= 'F')
+    {
+      ret = ch - 'A' + 10;
+    }
+  else if (ch >= 'a' && ch <= 'f')
+    {
+      ret = ch - 'a' + 10;
+    }
+  else
+    {
+      return -EINVAL;
+    }
+
+  *nibble = ret;
+  return OK;
+}
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -1160,6 +1190,145 @@ int cmd_nslookup(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 }
 #endif
 
+/****************************************************************************
+ * Name: cmd_arp
+ ****************************************************************************/
+
+#if defined(CONFIG_NET_ARP) && !defined(CONFIG_NSH_DISABLE_ARP)
+int cmd_arp(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  FAR char *ptr;
+  struct sockaddr_in inaddr;
+  struct ether_addr mac;
+  int ret;
+  int i;
+
+  /* Forms:
+   *
+   * aap -a <ipaddr>
+   * arp -d <ipdaddr>
+   * arp -s <ipaddr> <hwaddr>
+   */
+
+  if (strcmp(argv[1], "-a") == 0)
+    {
+      if (argc != 3)
+        {
+          goto errout_toomany;
+        }
+
+      /* Show the corresponding hardware address */
+
+      inaddr.sin_family      = AF_INET;
+      inaddr.sin_port        = INADDR_ANY;
+      inaddr.sin_addr.s_addr = inet_addr(argv[2]);
+
+      ret = netlib_get_arpmapping(&inaddr, mac.ether_addr_octet);
+      if (ret < 0)
+        {
+          goto errout_cmdfaild;
+        }
+
+      nsh_output(vtbl, "HWAddr: %s\n",  ether_ntoa(&mac));
+    }
+  else if (strcmp(argv[1], "-d") == 0)
+    {
+      if (argc != 3)
+        {
+          goto errout_toomany;
+        }
+
+      /* Delete the corresponding address mapping from the arp table */
+
+      inaddr.sin_family      = AF_INET;
+      inaddr.sin_port        = INADDR_ANY;
+      inaddr.sin_addr.s_addr = inet_addr(argv[2]);
+
+      ret = netlib_del_arpmapping(&inaddr);
+      if (ret < 0)
+        {
+          goto errout_cmdfaild;
+        }
+    }
+  else if (strcmp(argv[1], "-s") == 0)
+    {
+      unsigned int nibble;
+      unsigned int byte;
+      char delim;
+
+      if (argc != 4)
+        {
+          goto errout_missing;
+        }
+
+      /* Convert the MAC address string to a binary */
+
+      for (i = 0, ptr = argv[3]; i < ETHER_ADDR_LEN; i++)
+        {
+          ret = mac_nibble(*ptr++, &nibble);
+          if (ret < 0)
+            {
+              goto errout_invalid;
+            }
+
+          byte = nibble << 4;
+
+          ret = mac_nibble(*ptr++, &nibble);
+          if (ret < 0)
+            {
+              goto errout_invalid;
+            }
+
+          byte |= nibble;
+
+          delim = (i >= (ETHER_ADDR_LEN-1)) ? '\0' : ':';
+          if (*ptr++ != delim)
+            {
+              goto errout_invalid;
+            }
+
+          mac.ether_addr_octet[i] = byte;
+        }
+
+      /* Add the address mapping to the arp table */
+
+      inaddr.sin_family      = AF_INET;
+      inaddr.sin_port        = INADDR_ANY;
+      inaddr.sin_addr.s_addr = inet_addr(argv[2]);
+
+      ret = netlib_set_arpmapping(&inaddr, mac.ether_addr_octet);
+      if (ret < 0)
+        {
+          goto errout_cmdfaild;
+        }
+    }
+  else
+    {
+      goto errout_invalid;
+    }
+
+  return OK;
+
+/* Error exits */
+
+errout_cmdfaild:
+  nsh_output(vtbl, g_fmtcmdfailed, argv[0], "ioctl", NSH_ERRNO);
+  return ERROR;
+
+errout_missing:
+  nsh_output(vtbl, g_fmttoomanyargs, argv[0]);
+  return ERROR;
+
+errout_toomany:
+  nsh_output(vtbl, g_fmtargrequired, argv[0]);
+  return ERROR;
+
+errout_invalid:
+  nsh_output(vtbl, g_fmtarginvalid, argv[0]);
+  return ERROR;
+}
+#endif
+
 /****************************************************************************
  * Name: cmd_ping
  ****************************************************************************/