common/irs/getnameinfo.c

/*
 * Issues to be discussed:
 * - Thread safe-ness must be checked
 */

#if ( defined(__linux__) || defined(__linux) || defined(LINUX) )
#ifndef IF_NAMESIZE
# ifdef IFNAMSIZ
#  define IF_NAMESIZE  IFNAMSIZ
# else
#  define IF_NAMESIZE 16
# endif
#endif
#endif

/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by WIDE Project and
 *    its contributors.
 * 4. 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.
 */

#include <port_before.h>

#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <net/if.h>

#include <netdb.h>
#include <resolv.h>
#include <string.h>
#include <stddef.h>

#include <port_after.h>

/*%
 * Note that a_off will be dynamically adjusted so that to be consistent
 * with the definition of sockaddr_in{,6}.
 * The value presented below is just a guess.
 */
static struct afd {
    int a_af;
    int a_addrlen;
    size_t a_socklen;
    int a_off;
} afdl [] = {
    /* first entry is linked last... */
    {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
     offsetof(struct sockaddr_in, sin_addr)},
    {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
     offsetof(struct sockaddr_in6, sin6_addr)},
    {0, 0, 0, 0},
};

struct sockinet {
#ifdef HAVE_SA_LEN
    u_char  si_len;
#endif
    u_char  si_family;
    u_short si_port;
};

static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
                 size_t, int));
#ifdef HAVE_SIN6_SCOPE_ID
static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, int));
#endif

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 afd *afd;
    struct servent *sp;
    struct hostent *hp;
    u_short port;
#ifdef HAVE_SA_LEN
    size_t len;
#endif
    int family, i;
    const char *addr;
    char *p;
    char numserv[512];
    char numaddr[512];
    const struct sockaddr_in6 *sin6;

    if (sa == NULL)
        return EAI_FAIL;

#ifdef HAVE_SA_LEN
    len = sa->sa_len;
    if (len != salen) return EAI_FAIL;
#endif

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

 found:
    if (salen != afd->a_socklen) return EAI_FAIL;

    port = ((const struct sockinet *)sa)->si_port; /*%< network byte order */
    addr = (const char *)sa + afd->a_off;

    if (serv == NULL || servlen == 0U) {
        /*
         * rfc2553bis says that serv == NULL or servlen == 0 means that
         * the caller does not want the result.
         */
    } else if (flags & NI_NUMERICSERV) {
        sprintf(numserv, "%d", ntohs(port));
        if (strlen(numserv) > servlen)
            return EAI_MEMORY;
        strcpy(serv, numserv);
    } else {
        sp = getservbyport(port, (flags & NI_DGRAM) ? "udp" : "tcp");
        if (sp) {
            if (strlen(sp->s_name) + 1 > servlen)
                return EAI_MEMORY;
            strcpy(serv, sp->s_name);
        } else
            return EAI_NONAME;
    }

    switch (sa->sa_family) {
    case AF_INET:
        if (ntohl(*(const u_int32_t *)addr) >> IN_CLASSA_NSHIFT == 0)
            flags |= NI_NUMERICHOST;
        break;
    case AF_INET6:
        sin6 = (const struct sockaddr_in6 *)sa;
        switch (sin6->sin6_addr.s6_addr[0]) {
        case 0x00:
            if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
                ;
            else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
                ;
            else
                flags |= NI_NUMERICHOST;
            break;
        default:
            if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
                flags |= NI_NUMERICHOST;
            else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
                flags |= NI_NUMERICHOST;
            break;
        }
        break;
    }
    if (host == NULL || hostlen == 0U) {
        /*
         * rfc2553bis says that host == NULL or hostlen == 0 means that
         * the caller does not want the result.
         */
    } else if (flags & NI_NUMERICHOST) {
        goto numeric;
    } else {
        hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);

        if (hp) {
            if (flags & NI_NOFQDN) {
                p = strchr(hp->h_name, '.');
                if (p) *p = '\0';
            }
            if (strlen(hp->h_name) + 1 > hostlen)
                return EAI_MEMORY;
            strcpy(host, hp->h_name);
        } else {
            if (flags & NI_NAMEREQD)
                return EAI_NONAME;
          numeric:
            switch(afd->a_af) {
            case AF_INET6:
            {
                int error;

                if ((error = ip6_parsenumeric(sa, addr, host,
                                  hostlen,
                                  flags)) != 0)
                    return(error);
                break;
            }

            default:
                if (inet_ntop(afd->a_af, addr, numaddr,
                          sizeof(numaddr)) == NULL)
                    return EAI_NONAME;
                if (strlen(numaddr) + 1 > hostlen)
                    return EAI_MEMORY;
                strcpy(host, numaddr);
            }
        }
    }
    return(0);
}

static int
ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
         size_t hostlen, int flags)
{
    size_t numaddrlen;
    char numaddr[512];

#ifndef HAVE_SIN6_SCOPE_ID
    UNUSED(sa);
    UNUSED(flags);
#endif

    if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr))
        == NULL)
        return EAI_SYSTEM;

    numaddrlen = strlen(numaddr);
    if (numaddrlen + 1 > hostlen) /*%< don't forget terminator */
        return EAI_MEMORY;
    strcpy(host, numaddr);

#ifdef HAVE_SIN6_SCOPE_ID
    if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
        char scopebuf[MAXHOSTNAMELEN]; /*%< XXX */
        int scopelen;

        /* ip6_sa2str never fails */
        scopelen = ip6_sa2str((const struct sockaddr_in6 *)sa,
                      scopebuf, sizeof(scopebuf), flags);

        if (scopelen + 1 + numaddrlen + 1 > hostlen)
            return EAI_MEMORY;

        /* construct <numeric-addr><delim><scopeid> */
        memcpy(host + numaddrlen + 1, scopebuf,
               scopelen);
        host[numaddrlen] = SCOPE_DELIMITER;
        host[numaddrlen + 1 + scopelen] = '\0';
    }
#endif

    return 0;
}

#ifdef HAVE_SIN6_SCOPE_ID
/* ARGSUSED */
static int
ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf,
       size_t bufsiz, int flags)
{
#ifdef USE_IFNAMELINKID
    unsigned int ifindex = (unsigned int)sa6->sin6_scope_id;
    const struct in6_addr *a6 = &sa6->sin6_addr;
#endif
    char tmp[64];

#ifdef NI_NUMERICSCOPE
    if (flags & NI_NUMERICSCOPE) {
        sprintf(tmp, "%u", sa6->sin6_scope_id);
        if (bufsiz != 0U) {
            strncpy(buf, tmp, bufsiz - 1);
            buf[bufsiz - 1] = '\0';
        }
        return(strlen(tmp));
    }
#endif

#ifdef USE_IFNAMELINKID
    /*
     * For a link-local address, convert the index to an interface
     * name, assuming a one-to-one mapping between links and interfaces.
     * Note, however, that this assumption is stronger than the
     * specification of the scoped address architecture;  the
     * specficication says that more than one interfaces can belong to
     * a single link.
     */

    /* if_indextoname() does not take buffer size.  not a good api... */
    if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
        bufsiz >= IF_NAMESIZE) {
        char *p = if_indextoname(ifindex, buf);
        if (p) {
            return(strlen(p));
        }
    }
#endif

    /* last resort */
    sprintf(tmp, "%u", sa6->sin6_scope_id);
    if (bufsiz != 0U) {
        strncpy(buf, tmp, bufsiz - 1);
        buf[bufsiz - 1] = '\0';
    }
    return(strlen(tmp));
}
#endif

/*! \file */