Internet地址结构及转换

Internet地址的基本数据结构如下：

 #include <netinet/in.h>

 struct sockaddr_in {
     short            sin_family;      // e.g. AF_INET
     unsigned short   sin_port;  // e.g. htons(3490)
     struct in_addr   sin_addr;   // see struct in_addr, below
     char             sin_zero[8];    // zero this if you want to
 };

 struct in_addr {
     unsigned long s_addr;  // load with inet_aton()
 };

IP字符串转换到unsigned long：

 in_addr ip_addr;
 inet_aton("63.161.169.137", &ip_addr);

 

unsigned long转换到IP字符串：

 char ip[64];
 in_addr in;
 in.s_addr = htonl(176427304); //unsigned long to be converted
 strcpy(ip, inet_ntoa(in));
 printf("ip: %s\n", ip);

 

使用的时候只要include下面的头文件：

 #include <netinet/in.h>
 #include <arpa/inet.h>