getnameinfo.c

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Issues to be discussed:
 * - Thread safe-ness must be checked
 * - Return values.  There seems to be no standard for return value (RFC2133)
 *   but INRIA implementation returns EAI_xxx defined for getaddrinfo().
 */

#if 0
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>
#include <string.h>
#include <stddef.h>

#include "addrinfo.h"
#endif

#define SUCCESS 0
#define YES 1
#define NO  0

static struct gni_afd {
    int a_af;
    int a_addrlen;
    int a_socklen;
    int a_off;
} gni_afdl [] = {
#ifdef ENABLE_IPV6
    {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
        offsetof(struct sockaddr_in6, sin6_addr)},
#endif
    {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
        offsetof(struct sockaddr_in, sin_addr)},
    {0, 0, 0},
};

struct gni_sockinet {
    u_char      si_len;
    u_char      si_family;
    u_short     si_port;
};

#define ENI_NOSOCKET    0
#define ENI_NOSERVNAME  1
#define ENI_NOHOSTNAME  2
#define ENI_MEMORY      3
#define ENI_SYSTEM      4
#define ENI_FAMILY      5
#define ENI_SALEN       6

/* forward declaration to make gcc happy */
int getnameinfo(const struct sockaddr *, size_t, char *, size_t,
                          char *, size_t, int);

int
getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
    const struct sockaddr *sa;
    size_t salen;
    char *host;
    size_t hostlen;
    char *serv;
    size_t servlen;
    int flags;
{
    struct gni_afd *gni_afd;
    struct servent *sp;
    struct hostent *hp;
    u_short port;
    int family, len, i;
    char *addr, *p;
    u_long v4a;
#ifdef ENABLE_IPV6
    u_char pfx;
#endif
    int h_error;
    char numserv[512];
    char numaddr[512];

    if (sa == NULL)
        return ENI_NOSOCKET;

#ifdef HAVE_SOCKADDR_SA_LEN
    len = sa->sa_len;
    if (len != salen) return ENI_SALEN;
#else
    len = salen;
#endif

    family = sa->sa_family;
    for (i = 0; gni_afdl[i].a_af; i++)
        if (gni_afdl[i].a_af == family) {
            gni_afd = &gni_afdl[i];
            goto found;
        }
    return ENI_FAMILY;

 found:
    if (len != gni_afd->a_socklen) return ENI_SALEN;

    port = ((struct gni_sockinet *)sa)->si_port; /* network byte order */
    addr = (char *)sa + gni_afd->a_off;

    if (serv == NULL || servlen == 0) {
        /* what we should do? */
    } else if (flags & NI_NUMERICSERV) {
        sprintf(numserv, "%d", ntohs(port));
        if (strlen(numserv) > servlen)
            return ENI_MEMORY;
        strcpy(serv, numserv);
    } else {
        sp = getservbyport(port, (flags & NI_DGRAM) ? "udp" : "tcp");
        if (sp) {
            if (strlen(sp->s_name) > servlen)
                return ENI_MEMORY;
            strcpy(serv, sp->s_name);
        } else
            return ENI_NOSERVNAME;
    }

    switch (sa->sa_family) {
    case AF_INET:
        v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
        if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
            flags |= NI_NUMERICHOST;
        v4a >>= IN_CLASSA_NSHIFT;
        if (v4a == 0 || v4a == IN_LOOPBACKNET)
            flags |= NI_NUMERICHOST;
        break;
#ifdef ENABLE_IPV6
    case AF_INET6:
        pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0];
        if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
            flags |= NI_NUMERICHOST;
        break;
#endif
    }
    if (host == NULL || hostlen == 0) {
        /* what should we do? */
    } else if (flags & NI_NUMERICHOST) {
        if (inet_ntop(gni_afd->a_af, addr, numaddr, sizeof(numaddr))
            == NULL)
            return ENI_SYSTEM;
        if (strlen(numaddr) > hostlen)
            return ENI_MEMORY;
        strcpy(host, numaddr);
    } else {
#ifdef ENABLE_IPV6
        hp = getipnodebyaddr(addr, gni_afd->a_addrlen, gni_afd->a_af, &h_error);
#else
        hp = gethostbyaddr(addr, gni_afd->a_addrlen, gni_afd->a_af);
        h_error = h_errno;
#endif

        if (hp) {
            if (flags & NI_NOFQDN) {
                p = strchr(hp->h_name, '.');
                if (p) *p = '\0';
            }
            if (strlen(hp->h_name) > hostlen) {
#ifdef ENABLE_IPV6
                freehostent(hp);
#endif
                return ENI_MEMORY;
            }
            strcpy(host, hp->h_name);
#ifdef ENABLE_IPV6
            freehostent(hp);
#endif
        } else {
            if (flags & NI_NAMEREQD)
                return ENI_NOHOSTNAME;
            if (inet_ntop(gni_afd->a_af, addr, numaddr, sizeof(numaddr))
                == NULL)
                return ENI_NOHOSTNAME;
            if (strlen(numaddr) > hostlen)
                return ENI_MEMORY;
            strcpy(host, numaddr);
        }
    }
    return SUCCESS;
}