lwip IP address handling 关于 IP 地址的 操作 API接口

lwip 2.0.3  IP address handling 

/**
* @file
* IP address API (common IPv4 and IPv6)
*/

1、u32_t ipaddr_addr(const char *cp);

　　把一个 字符串的 IP 地址转换成  ip4_addr_t 类型的IP。

/**
 * Ascii internet address interpretation routine.
 * The value returned is in network order.
 *
 * @param cp IP address in ascii representation (e.g. "127.0.0.1")
 * @return ip address in network order
 */
u32_t
ipaddr_addr(const char *cp)
{
  ip4_addr_t val;

  if (ip4addr_aton(cp, &val)) {
    return ip4_addr_get_u32(&val);
  }
  return (IPADDR_NONE);
}

2、char *ip4addr_ntoa(const ip4_addr_t *addr);

　　把一个 ip4_addr_t 类型 的IP地址 转换 成 字符串形式！

/**
 * Convert numeric IP address into decimal dotted ASCII representation.
 * returns ptr to static buffer; not reentrant!
 *
 * @param addr ip address in network order to convert
 * @return pointer to a global static (!) buffer that holds the ASCII
 *         representation of addr
 */
char*
ip4addr_ntoa(const ip4_addr_t *addr)
{
  static char str[IP4ADDR_STRLEN_MAX];
  return ip4addr_ntoa_r(addr, str, IP4ADDR_STRLEN_MAX);
}