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域名,ip相互转换(Linux,getaddrinfo, getnameinfo)--- 转

参考链接:

http://en.wikipedia.org/wiki/Getaddrinfo

代码:

 

01/* ip_to_hostname ip */
02#include <sys/types.h>
03#include <sys/socket.h>
04#include <netdb.h>
05#include <unistd.h>
06#include <stdio.h>
07#include <stdlib.h>
08#include <string.h>
09 
10int main(int argc, char *argv[])
11{
12        if (argc != 2)
13        {
14                fprintf(stderr, "Usage: %s hostname\n", argv[0]);
15                exit(EXIT_FAILURE);
16        }
17        struct addrinfo hints;
18        struct addrinfo *result, *result_pointer;
19        int ret;
20        /* obtaining address matching host */
21        memset(&hints, 0, sizeof(struct addrinfo));
22        hints.ai_family = AF_UNSPEC;
23        hints.ai_socktype = SOCK_STREAM;
24        hints.ai_flags = AI_CANONNAME | AI_NUMERICHOST;
25        hints.ai_protocol = 0;  /* any protocol */
26 
27//      ret = getaddrinfo(argv[1], NULL, &hints, &result);                                                                                                            
28        ret = getaddrinfo(argv[1], NULL, &hints, &result);
29        if (ret != 0)
30        {
31                fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret));
32                exit(EXIT_FAILURE);
33        }
34        /* traverse the returned list and output the ip addresses */
35        for (result_pointer = result; result_pointer != NULL; result_pointer = result_pointer->ai_next)
36        {
37                char hostname[1025] = "";
38                ret = getnameinfo(result_pointer->ai_addr, result_pointer->ai_addrlen, hostname, sizeof(hostname), NULL, 0, NI_NAMEREQD);
39                if (ret != 0)
40                {
41                        fprintf(stderr, "error in getnameinfo: %s \n", gai_strerror(ret));
42                }
43                else
44                {
45                        printf("hostname: %s \n", hostname);
46                }
47//              printf("hostname: %s \n", result_pointer->ai_canonname);                                                                                              
48        }
49        freeaddrinfo(result);
50        exit(EXIT_SUCCESS);
51}

 

 

01/* hostname_to_ip hostname */
02#include <sys/types.h>
03#include <sys/socket.h>
04#include <netdb.h>
05#include <unistd.h>
06#include <stdio.h>
07#include <stdlib.h>
08#include <string.h>
09 
10int main(int argc, char *argv[])
11{
12        if (argc != 2)
13        {
14                fprintf(stderr, "Usage: %s hostname\n", argv[0]);
15                exit(EXIT_FAILURE);
16        }
17        struct addrinfo hints;
18        struct addrinfo *result, *result_pointer;
19        int ret;
20        /* obtaining address matching host */
21        memset(&hints, 0, sizeof(struct addrinfo));
22        hints.ai_family = AF_UNSPEC;
23        hints.ai_socktype = SOCK_STREAM;
24        hints.ai_flags = AI_CANONNAME;
25        hints.ai_protocol = 0;  /* any protocol */
26 
27//      ret = getaddrinfo(argv[1], NULL, &hints, &result);                                                                                                            
28        ret = getaddrinfo(argv[1], NULL, &hints, &result);
29        if (ret != 0)
30        {
31                fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret));
32                exit(EXIT_FAILURE);
33        }
34        /* traverse the returned list and output the ip addresses */
35        for (result_pointer = result; result_pointer != NULL; result_pointer = result_pointer->ai_next)
36        {
37                char hostname[1025] = "";
38                ret = getnameinfo(result_pointer->ai_addr, result_pointer->ai_addrlen, hostname, sizeof(hostname), NULL, 0, NI_NUMERICHOST);
39                if (ret != 0)
40                {
41                        fprintf(stderr, "error in getnameinfo: %s \n", gai_strerror(ret));
42                        continue;
43                }
44                else
45                {
46                        printf("IP: %s \n", hostname);
47                }
48        }
49        freeaddrinfo(result);
50        exit(EXIT_SUCCESS);
51}

 

结果:

root@localhost :/home/James/mypro/Linux-Pro/Network# ./hostname_to_ip baidu.com
IP: 123.125.114.144
IP: 220.181.111.85
IP: 220.181.111.86
root@localhost :/home/James/mypro/Linux-Pro/Network# ./ip_to_hostname 220.181.111.86
error in getnameinfo: Name or service not known
root@localhost :/home/James/mypro/Linux-Pro/Network# ./ip_to_hostname 10.0.0.78
hostname: localhost

root@localhost:/home/James/mypro/Linux-Pro/Network# ./ip_to_hostname 59.66.137.62
hostname: th137062.ip.tsinghua.edu.cn
root@localhost:/home/James/mypro/Linux-Pro/Network# ./ip_to_hostname 202.106.182.229
hostname: mail182-229.sinamail.sina.com.cn
root@localhost:/home/James/mypro/Linux-Pro/Network# ./ip_to_hostname 211.147.4.7
hostname: mail3.douban.com

posted on 2012-11-12 14:44 大龙 阅读(3992) 评论(0)  编辑 收藏 引用


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