getaddrinfo-test

getaddrinfo-test.c

#ifdef _WIN32
#include <ws2tcpip.h>
#include <in6addr.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif

#include <inttypes.h>
#include <ctype.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef _WIN32
#include <malloc.h>
#endif

struct net_addr {
    uint16_t family;
    union {
        struct in_addr  ipv4;
        struct in6_addr ipv6;
    };
    int64_t ts_hyb;
};

struct dns_response {
    const char *cname;
    char *canon_name;
    struct net_addr *a;
    int err;
    int denied;
    int64_t cost_ms;
};

int main(int argc, char **argv)
{
    int r = 111;
    const char *dname;
    struct addrinfo *i, *info = NULL, hints;
    struct dns_response ret;
    size_t max_n, k = 0;
#ifdef _WIN32
    WSADATA Data;
#endif

    memset(&ret, 0, sizeof(ret));
#ifdef _WIN32
    WSAStartup(MAKEWORD(2, 0), &Data);
#endif

    if (argc < 2) {
        fprintf(stderr, "usage: %s <domain_name>\n", argv ? argv[0] : "");
        r = 1;
        goto out;
    }

    dname = argv[1];

    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_flags = AI_CANONNAME;

    ret.cname = dname;
    ret.err = getaddrinfo(dname, NULL, &hints, &info);

    fprintf(stdout, "%s:\n", dname);
    if (ret.err) {
        fprintf(stdout, "getaddrinfo FAILED err %d\n", ret.err);
        r = 0;
        goto out;
    }

    max_n = 0;
    for (i = info; i; i = i->ai_next)
        max_n++;

    if (!max_n)
        goto out;
    max_n += 1; /* for the NULL one */

    ret.a = calloc(1, max_n * sizeof(*ret.a));
    if (!ret.a) {
        ret.err = EAI_MEMORY;
        fprintf(stderr, "%s: memory error\n", __FUNCTION__);
        r = 2;
        goto out;
    }


    if (info && info->ai_canonname && !ret.canon_name) {
        fprintf(stdout, "ptr: %p, %s\n", info->ai_canonname, info->ai_canonname);
        ret.canon_name = strdup(info->ai_canonname);
    }

    for (i = info; i; i = i->ai_next) {
        int j;

        if (!i->ai_addr || (i->ai_family != AF_INET && i->ai_family != AF_INET6))
            continue;

        if (i->ai_family == AF_INET) {
            struct in_addr addr;

            if (i->ai_addrlen < sizeof(struct sockaddr_in))
                continue;
            addr = ((struct sockaddr_in *) i->ai_addr)->sin_addr;
            for (j = 0; j < k; j++) {
                if (ret.a[j].family != AF_INET)
                    continue;
                if (addr.s_addr == ret.a[j].ipv4.s_addr)
                    break;
            }
            if (j != k)
                continue;
            ret.a[k].family = AF_INET;
            ret.a[k].ipv4 = addr;
        } else { /* IPv6 */
            struct in6_addr addr;

            if (i->ai_addrlen < sizeof(struct sockaddr_in6))
                continue;
            addr = ((struct sockaddr_in6 *)i->ai_addr)->sin6_addr;
            for (j = 0; j < k; j++) {
                if (ret.a[j].family != AF_INET6)
                    continue;
                if (memcmp(&addr, &ret.a[j].ipv6, sizeof(addr)) == 0)
                    break;
            }
            if (j != k)
                continue;
            ret.a[k].family = AF_INET6;
            ret.a[k].ipv6 = ((struct sockaddr_in6 *)i->ai_addr)->sin6_addr;
        }
        k++;
        
        fprintf(stdout, "flags: 0x%08x\n", i->ai_flags);
    }

    if (ret.canon_name && strcasecmp(ret.canon_name, dname))
        fprintf(stdout, "CANON NAME len %u '%s'\n", (unsigned) strlen(ret.canon_name), ret.canon_name);

    if ((unsigned) strlen(ret.canon_name) > 100) {
        fprintf(stdout, "BROKEN!!!\n");
        fprintf(stdout, "GREP-MARKER-XXX: ");
        for (unsigned i=0; i<(unsigned)strlen(ret.canon_name); i++) {
            fprintf(stdout, "%.2x", *(unsigned char *)((info->ai_canonname)+i));
        }
        fprintf(stdout, "\n");
    }


    k = 0;
    while (ret.a && ret.a[k].family) {
        if (ret.a[k].family == AF_INET) {
            char *ss_addr;

            ss_addr = inet_ntoa(ret.a[k].ipv4);
            fprintf(stdout, "A %s\n", ss_addr ? ss_addr : "(invalid)");
        }
        k++;
    }

    r = 0;

out:
    fprintf(stdout, "\n");
    if (info)
        freeaddrinfo(info);
    free(ret.a);
#ifdef _WIN32
    WSACleanup();
#endif

    return r;
}