#include	<stdlib.h>
#include	<stdio.h>
#include	<netdb.h>
#include	<arpa/inet.h>


/*
 * ===  FUNCTION  ======================================================================
 *         Name:  main
 *  Description: 注意h_aliases指向指针数组，注意netname的增减。
 * =====================================================================================
 */
int
main ( int argc, char *argv[] )
{
        char **netname = NULL;
        struct hostent *tmp;
        char a[INET_ADDRSTRLEN];

        while ((tmp = gethostent()) != NULL) {
                printf("netname: %s\n", tmp->h_name);
                for (netname = tmp->h_aliases; *netname != NULL; netname++)  {
                        printf("alias : %s\n", *netname);
                }

                printf("%d\n", tmp->h_addrtype);
                for (int i = 0; tmp->h_addr_list[i] != NULL; i++) {
                        printf("ip  %s\n",  inet_ntop(AF_INET, tmp->h_addr_list[i], a, INET_ADDRSTRLEN));
                }
                printf("\n");
        }
        endnetent();
        return EXIT_SUCCESS;
}				/* ----------  end of function main  ---------- */

#include	<stdlib.h>
#include	<stdio.h>
#include	<netdb.h>
#include	<arpa/inet.h>


/*
 * ===  FUNCTION  ======================================================================
 *         Name:  main
 *  Description: getnetent，此命令的实现问题在于只是读取了/etc/networks里的内
 *  容，对本机地址，主机名等并不探测，目前尚不了解此命令的限定。
 * =====================================================================================
 */
int
main ( int argc, char *argv[] )
{
        char *netname = NULL;
        struct netent *tmp;
        char a[INET_ADDRSTRLEN];

        while ((tmp = getnetent()) != NULL) {
                printf("netname: %s\n", tmp->n_name);
                for (netname = *(tmp->n_aliases); netname != NULL; netname++)  {
                        printf("alias : %s\n", netname);
                }
                printf("%d\n", tmp->n_addrtype);
                int iii = tmp->n_net;
                printf("ip  %s\n",  inet_ntop(AF_INET, &iii, a, INET_ADDRSTRLEN));
        }
        endnetent();
        return EXIT_SUCCESS;
}				/* ----------  end of function main  ---------- */

#include	<stdio.h>
#include	<stdlib.h>
#include	<netdb.h>
#include	<arpa/inet.h>

/*
 * ===  FUNCTION  ======================================================================
 *         Name:  main
 *  Description: 只是协议名字与端口号，例如TCP IP协议等。依赖于/etc/protocols文件
 * =====================================================================================
 */
int
main ( int argc, char *argv[] )
{
        char **name;
        struct protoent *tmp;

        while ((tmp = getprotoent()) != NULL) {
                printf("protocol name: %s\n", tmp->p_name);
                for (name = tmp->p_aliases; *name != NULL; name++) {
                        printf("alias: %s \n", *name);
                }
                printf("protocol num: %d\n", tmp->p_proto);
        }
        endprotoent();
        return EXIT_SUCCESS;
}				/* ----------  end of function main  ---------- */

#include	<stdio.h>
#include	<stdlib.h>
#include	<netdb.h>
#include	<arpa/inet.h>

/*
 * ===  FUNCTION  ======================================================================
 *         Name:  main
 *  Description: 获取服务名字，采用协议与端口号等，例如www服务，ftp服务。参照/etc/services文件获取
 * =====================================================================================
 */
int
main ( int argc, char *argv[] )
{
        char **name;
        struct servent *tmp;

        while ((tmp = getservent()) != NULL) {
                printf("service name: %s\n", tmp->s_name);
                for (name = tmp->s_aliases; *name != NULL; name++) {
                        printf("alias: %s \n", *name);
                }
                printf("port num: %d\n", ntohs(tmp->s_port));
                printf("protocol name: %s\n", tmp->s_proto);
                printf("\n\n\n");
        }
        endservent();
        return EXIT_SUCCESS;
}				/* ----------  end of function main  ---------- */

#include	<stdio.h>
#include	<stdlib.h>
#include	<sys/socket.h>
#include	<netdb.h>
#include	<arpa/inet.h>

/*
 * ===  FUNCTION  ======================================================================
 *         Name:  getaddrinfo
 *  Description:  注意错误消息要调用gai_strerror。
 *  		  hint，还有struct sockaddr到sockaddr_in的转变。且sin_port为网
 *  		 网络字节序。
 * =====================================================================================
 */
int
main ( int argc, char *argv[] )
{
        int err;
        char *name;
        struct addrinfo *ailist;
        struct addrinfo hint;
        struct sockaddr_in *sinp;
        char addr[INET_ADDRSTRLEN];

        hint.ai_flags = AI_CANONNAME;
        hint.ai_family = AF_INET;
        hint.ai_socktype = 0;
        hint.ai_protocol = 0;
        hint.ai_canonname = NULL;
        hint.ai_addr = NULL;
        hint.ai_next = NULL;
        if ((err = getaddrinfo(argv[1], argv[2], &hint, &ailist)) != 0) { /* 注意返回值 */
                printf("%s \n", gai_strerror(err));
                exit(1);
        }
        do {
                printf("family: %d \n", ailist->ai_family);
                printf("socktype: %d \n", ailist->ai_socktype);
                if (ailist->ai_family == AF_INET) {
                        sinp = (struct sockaddr_in *)ailist->ai_addr;
                        printf("port: %d\n", ntohs(sinp->sin_port));
                        name = inet_ntop(AF_INET, &sinp->sin_addr, addr, INET_ADDRSTRLEN);
                        printf("addr: %s\n", name ? name : "fuck addr");
                        printf("canonname %s\n", ailist->ai_canonname);
                }
        } while ((ailist = ailist->ai_next) != NULL);
        freeaddrinfo(ailist);
        return EXIT_SUCCESS;
}				/* ----------  end of function main  ---------- */

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