dns_rr_eq_sa.c

[詳解]

/*++
/* NAME
/*  dns_rr_eq_sa 3
/* SUMMARY
/*  compare resource record with socket address
/* SYNOPSIS
/*  #include <dns.h>
/*
/*  int dns_rr_eq_sa(DNS_RR *rr, struct sockaddr *sa)
/*  DNS_RR  *rr;
/*  struct sockaddr *sa;
/*
/*  int DNS_RR_EQ_SA(DNS_RR *rr, struct sockaddr *sa)
/*  DNS_RR  *rr;
/*  struct sockaddr *sa;
/* DESCRIPTION
/*  dns_rr_eq_sa() compares a DNS resource record with a socket
/*  address.  The result is non-zero when the resource type
/*  matches the socket address family, and when the network
/*  address information is identical.
/*
/*  DNS_RR_EQ_SA() is an unsafe macro version for those who live fast.
/*
/*  Arguments:
/* .IP rr
/*  DNS resource record pointer.
/* .IP sa
/*  Binary address pointer.
/* DIAGNOSTICS
/*  Panic: unknown socket address family.
/* 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>

/* Utility library. */

#include <msg.h>
#include <sock_addr.h>

/* DNS library. */

#include <dns.h>

/* dns_rr_eq_sa - compare resource record with socket address */

int     dns_rr_eq_sa(DNS_RR *rr, struct sockaddr *sa)
{
    const char *myname = "dns_rr_eq_sa";

    if (sa->sa_family == AF_INET) {
    return (rr->type == T_A
        && SOCK_ADDR_IN_ADDR(sa).s_addr == IN_ADDR(rr->data).s_addr);
#ifdef HAS_IPV6
    } else if (sa->sa_family == AF_INET6) {
    return (rr->type == T_AAAA
        && memcmp((void *) &SOCK_ADDR_IN6_ADDR(sa),
              rr->data, rr->data_len) == 0);
#endif
    } else {
    msg_panic("%s: unsupported socket address family type: %d",
          myname, sa->sa_family);
    }
}

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

static const char *myname;

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

static int compare_family(const void *a, const void *b)
{
    struct addrinfo *resa = *(struct addrinfo **) a;
    struct addrinfo *resb = *(struct addrinfo **) b;

    return (resa->ai_family - resb->ai_family);
}

int     main(int argc, char **argv)
{
    MAI_HOSTADDR_STR hostaddr;
    DNS_RR *rr;
    struct addrinfo *res0;
    struct addrinfo *res1;
    struct addrinfo *res;
    struct addrinfo **resv;
    size_t  len, n;
    int     aierr;

    myname = argv[0];

    if (argc < 3)
    usage();

    inet_proto_init(argv[0], INET_PROTO_NAME_ALL);

    while (*++argv) {
    if (argv[1] == 0)
        usage();

    if ((aierr = hostaddr_to_sockaddr(argv[1], (char *) 0, 0, &res1)) != 0)
        msg_fatal("host address %s: %s", argv[1], MAI_STRERROR(aierr));
    if ((rr = dns_sa_to_rr(argv[1], 0, res1->ai_addr)) == 0)
        msg_fatal("dns_sa_to_rr: %m");
    freeaddrinfo(res1);

    if ((aierr = hostname_to_sockaddr(argv[0], (char *) 0, 0, &res0)) != 0)
        msg_fatal("host name %s: %s", argv[0], MAI_STRERROR(aierr));
    for (len = 0, res = res0; res != 0; res = res->ai_next)
        len += 1;
    resv = (struct addrinfo **) mymalloc(len * sizeof(*resv));
    for (len = 0, res = res0; res != 0; res = res->ai_next)
        resv[len++] = res;
    qsort((void *) resv, len, sizeof(*resv), compare_family);
    for (n = 0; n < len; n++) {
        SOCKADDR_TO_HOSTADDR(resv[n]->ai_addr, resv[n]->ai_addrlen,
                 &hostaddr, (MAI_SERVPORT_STR *) 0, 0);
        vstream_printf("%s =?= %s\n", hostaddr.buf, argv[1]);
        vstream_printf("tested by function: %s\n",
               dns_rr_eq_sa(rr, resv[n]->ai_addr) ?
               "yes" : "no");
        vstream_printf("tested by macro:    %s\n",
               DNS_RR_EQ_SA(rr, resv[n]->ai_addr) ?
               "yes" : "no");
    }
    dns_rr_free(rr);
    freeaddrinfo(res0);
    myfree((void *) resv);
    vstream_fflush(VSTREAM_OUT);
    argv += 1;
    }
    return (0);
}

#endif