libs/libc/net: Add inet_aton()

libs/libc/net/Make.defs

@@ -36,7 +36,8 @@
 # Add the networking C files to the build
 
 CSRCS += lib_addrconfig.c lib_etherntoa.c lib_htons.c lib_htonl.c
-CSRCS += lib_inetaddr.c lib_inetntoa.c lib_inetntop.c lib_inetpton.c
+CSRCS += lib_inetaddr.c lib_inetaton.c lib_inetntoa.c
+CSRCS += lib_inetntop.c lib_inetpton.c
 
 ifeq ($(CONFIG_NET),y)
 CSRCS += lib_shutdown.c

libs/libc/net/lib_inetaton.c

@@ -0,0 +1,125 @@
+/****************************************************************************
+ * libs/libc/net/lib_inetaton
+ *
+ *   Copyright (C) 2018 Gregory Nutt. All rights reserved.
+ *   Author: Juha Niskanen <juha.niskanen@haltian.com>
+ *
+ * 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 <stdint.h>
+#include <arpa/inet.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: inet_aton
+ *
+ * Description:
+ *   The inet_aton() function converts the string pointed to by cp, in the
+ *   standard IPv4 dotted decimal notation, to an integer value suitable for
+ *   use as an Internet address.
+ *
+ * Note:
+ *   inet_aton() returns nonzero if the address is valid, zero if not.
+ *   Therefore macros OK and ERROR are not used here.
+ *
+ ****************************************************************************/
+
+int inet_aton(FAR const char *cp, FAR struct in_addr *inp)
+{
+  int dots = 0;
+  uint32_t num = 0;
+  uint32_t addr = 0;
+  int c;
+
+  do
+    {
+      c = *cp;
+
+      switch (c)
+        {
+          case '0':
+          case '1':
+          case '2':
+          case '3':
+          case '4':
+          case '5':
+          case '6':
+          case '7':
+          case '8':
+          case '9':
+            num = 10 * num + (c - '0');
+            break;
+
+          case '.':
+            dots++;
+            if (dots > 3)
+              {
+                return 0;
+              }
+
+            /* no break */
+
+          case '\0':
+            if (num > 255)
+              {
+                return 0;
+              }
+
+            addr = addr << 8 | num;
+            num = 0;
+            break;
+
+          default:
+            return 0;
+        }
+    }
+  while (*cp++);
+
+  /* Normalize it */
+
+  if (dots < 3)
+    {
+      addr <<= 8 * (3 - dots);
+    }
+
+  if (inp)
+    {
+      inp->s_addr = HTONL(addr);
+    }
+
+  return 1;
+}