getnameinfo.c

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/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 *
 * Changes Copyright (C) 2001 by Martin Pool <mbp@samba.org>
 *
 * 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().
 */

#include "rsync.h"

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

static struct afd {
        int a_af;
        int a_addrlen;
        int a_socklen;
        int a_off;
} afdl [] = {
#ifdef INET6
        {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, 0},
};

struct 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

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;
{
        extern int h_errno;
        struct afd *afd;
        struct servent *sp;
        struct hostent *hp;
        u_short port;
        int family, i;
        char *addr, *p;
        u_long v4a;
#ifdef INET6
        u_char pfx;
#endif
        int h_error;
        char numserv[512];
        char numaddr[512];

        if (sa == NULL)
                return ENI_NOSOCKET;

#ifdef HAVE_SOCKADDR_LEN
        if (sa->sa_len != salen) return ENI_SALEN;
#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 ENI_FAMILY;
        
 found:
        if (salen != afd->a_socklen) return ENI_SALEN;
        
        port = ((struct sockinet *)sa)->si_port; /* network byte order */
        addr = (char *)sa + afd->a_off;

        if (serv == NULL || servlen == 0) {
                /* what we should do? */
        } else if (flags & NI_NUMERICSERV) {
                snprintf(numserv, sizeof(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 INET6
        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(afd->a_af, addr, numaddr, sizeof(numaddr)))
                        return ENI_SYSTEM;
                if (strlen(numaddr) > hostlen)
                        return ENI_MEMORY;
                strcpy(host, numaddr);
        } else {
#ifdef INET6
                hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
#else
                hp = gethostbyaddr(addr, afd->a_addrlen, 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 INET6
                                freehostent(hp);
#endif
                                return ENI_MEMORY;
                        }
                        strcpy(host, hp->h_name);
#ifdef INET6
                        freehostent(hp);
#endif
                } else {
                        if (flags & NI_NAMEREQD)
                                return ENI_NOHOSTNAME;
                        if (!inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)))
                                return ENI_NOHOSTNAME;
                        if (strlen(numaddr) > hostlen)
                                return ENI_MEMORY;
                        strcpy(host, numaddr);
                }
        }
        return SUCCESS;
}

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