dns_rr_to_pa.c

[詳解]

/*++
/* NAME
/*  dns_rr_to_pa 3
/* SUMMARY
/*  resource record to printable address
/* SYNOPSIS
/*  #include <dns.h>
/*
/*  const char *dns_rr_to_pa(rr, hostaddr)
/*  DNS_RR  *rr;
/*  MAI_HOSTADDR_STR *hostaddr;
/* DESCRIPTION
/*  dns_rr_to_pa() converts the address in a DNS resource record
/*  into printable form and returns a pointer to the result.
/*
/*  Arguments:
/* .IP rr
/*  The DNS resource record.
/* .IP hostaddr
/*  Storage for the printable address.
/* DIAGNOSTICS
/*  The result is null in case of problems, with errno set
/*  to indicate the nature of the problem.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

/* System libraries. */

#include <sys_defs.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>

/* Utility library. */

#include <msg.h>

/* DNS library. */

#include <dns.h>

/* dns_rr_to_pa - resource record to printable address */

const char *dns_rr_to_pa(DNS_RR *rr, MAI_HOSTADDR_STR *hostaddr)
{
    if (rr->type == T_A) {
    return (inet_ntop(AF_INET, rr->data, hostaddr->buf,
              sizeof(hostaddr->buf)));
#ifdef HAS_IPV6
    } else if (rr->type == T_AAAA) {
    return (inet_ntop(AF_INET6, rr->data, hostaddr->buf,
              sizeof(hostaddr->buf)));
#endif
    } else {
    errno = EAFNOSUPPORT;
    return (0);
    }
}

 /*
  * Stand-alone test program.
  */
#ifdef TEST
#include <vstream.h>
#include <myaddrinfo.h>

static const char *myname;

static NORETURN usage(void)
{
    msg_fatal("usage: %s dnsaddrtype hostname", myname);
}

int     main(int argc, char **argv)
{
    DNS_RR *rr;
    MAI_HOSTADDR_STR hostaddr;
    VSTRING *why;
    int     type;

    myname = argv[0];
    if (argc < 3)
    usage();
    why = vstring_alloc(1);

    while (*++argv) {
    if (argv[1] == 0)
        usage();
    if ((type = dns_type(argv[0])) == 0)
        usage();
    if (dns_lookup(argv[1], type, 0, &rr, (VSTRING *) 0, why) != DNS_OK)
        msg_fatal("%s: %s", argv[1], vstring_str(why));
    if (dns_rr_to_pa(rr, &hostaddr) == 0)
        msg_fatal("dns_rr_to_sa: %m");
    vstream_printf("%s -> %s\n", argv[1], hostaddr.buf);
    vstream_fflush(VSTREAM_OUT);
    argv += 1;
    dns_rr_free(rr);
    }
    vstring_free(why);
    return (0);
}

#endif