16-9.c

#include "apue.h"
#if defined(SOLARIS)
#include <netinet/in.h>
#endif
#include <arpa/inet.h>
#include <netdb.h>
#if defined(BSD)
#include <netinet/in.h>
#include <sys/socket.h>
#endif

void print_family(struct addrinfo *aip) {
    printf(" family ");
    switch (aip->ai_family) {
        case AF_INET:
            printf("inet");
            break;
        case AF_INET6:
            printf("inet6");
            break;
        case AF_UNIX:
            printf("unix");
            break;
        case AF_UNSPEC:
            printf("unspecified");
            break;
        default:
            printf("unknown");
    }
}

void print_type(struct addrinfo *aip) {
    printf(" type ");
    switch (aip->ai_socktype) {
        case SOCK_STREAM:
            printf("stream");
            break;
        case SOCK_DGRAM:
            printf("datagram");
            break;
        case SOCK_SEQPACKET:
            printf("seqpacket");
            break;
        case SOCK_RAW:
            printf("raw");
            break;
        default:
            printf("unknown (%d)", aip->ai_socktype);
    }
}

void print_protocol(struct addrinfo *aip) {
    printf(" protocol ");
    switch (aip->ai_protocol) {
        case 0:
            printf("default");
            break;
        case IPPROTO_TCP:
            printf("TCP");
            break;
        case IPPROTO_UDP:
            printf("UDP");
            break;
        case IPPROTO_RAW:
            printf("raw");
            break;
        default:
            printf("unknown (%d)", aip->ai_protocol);
    }
}

void print_flags(struct addrinfo *aip) {
    printf("flags");
    if (aip->ai_flags == 0) {
        printf(" 0");
    } else {
        if (aip->ai_flags & AI_PASSIVE) {
            printf(" passive");
        }
        if (aip->ai_flags & AI_CANONNAME) {
            printf(" canon");
        }
        if (aip->ai_flags & AI_NUMERICHOST) {
            printf(" numhost");
        }
        if (aip->ai_flags & AI_NUMERICSERV) {
            printf(" numserv");
        }
        if (aip->ai_flags & AI_V4MAPPED) {
            printf(" v4mapped");
        }
        if (aip->ai_flags & AI_ALL) {
            printf(" all");
        }
    }
}

int main(int argc, char *argv[]) {
    struct addrinfo *ailist, *aip;
    struct addrinfo hint;
    struct sockaddr_in *sinp;
    const char *addr;
    int err;
    char abuf[INET_ADDRSTRLEN];

    if (argc != 3) {
        err_quit("usage: %s nodename service", argv[0]);
    }

    hint.ai_flags = AI_CANONNAME;
    hint.ai_family = 0;
    hint.ai_socktype = 0;
    hint.ai_protocol = 0;
    hint.ai_addrlen = 0;
    hint.ai_canonname = NULL;
    hint.ai_addr = NULL;
    hint.ai_next = NULL;
    if ((err = getaddrinfo(argv[1], argv[2], &hint, &ailist)) != 0) {
        err_quit("getaddrinfo error: %s", gai_strerror(err));
    }

    for (aip = ailist; aip != NULL; aip = aip->ai_next) {
        print_flags(aip);
        print_family(aip);
        print_type(aip);
        print_protocol(aip);
        printf("\n\thost %s", aip->ai_canonname ? aip->ai_canonname : "-");

        if (aip->ai_family == AF_INET) {
            sinp = (struct sockaddr_in *)aip->ai_addr;
            addr = inet_ntop(AF_INET, &sinp->sin_addr, abuf, INET_ADDRSTRLEN);
            printf(" address %s", addr ? addr : "unknown");
            printf(" port %d", ntohs(sinp->sin_port));
        }
        printf("\n");
    }
    exit(0);
}