/*
 * Copyright (C) 2000-2003 Damien Miller.  All rights reserved.
 * Copyright (C) 1999 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.
 */

/*
 * Pseudo-implementation of RFC2553 name / address resolution functions
 *
 * But these functions are not implemented correctly. The minimum subset
 * is implemented for ssh use only. For example, this routine assumes
 * that ai_family is AF_INET. Don't use it for another purpose.
 */

#include "includes.h"

#include <stdlib.h>
#include <string.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#ifndef HAVE_GETNAMEINFO
int getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
                size_t hostlen, char *serv, size_t servlen, int flags)
{
        struct sockaddr_in *sin = (struct sockaddr_in *)sa;
        struct hostent *hp;
        char tmpserv[16];

        if (sa->sa_family != AF_UNSPEC && sa->sa_family != AF_INET)
                return (EAI_FAMILY);
        if (serv != NULL) {
                snprintf(tmpserv, sizeof(tmpserv), "%d", ntohs(sin->sin_port));
                if (strlcpy(serv, tmpserv, servlen) >= servlen)
                        return (EAI_MEMORY);
        }

        if (host != NULL) {
                if (flags & NI_NUMERICHOST) {
                        if (strlcpy(host, inet_ntoa(sin->sin_addr),
                            hostlen) >= hostlen)
                                return (EAI_MEMORY);
                        else
                                return (0);
                } else {
                        hp = gethostbyaddr((char *)&sin->sin_addr,
                            sizeof(struct in_addr), AF_INET);
                        if (hp == NULL)
                                return (EAI_NODATA);

                        if (strlcpy(host, hp->h_name, hostlen) >= hostlen)
                                return (EAI_MEMORY);
                        else
                                return (0);
                }
        }
        return (0);
}
#endif /* !HAVE_GETNAMEINFO */

#ifndef HAVE_GAI_STRERROR
#ifdef HAVE_CONST_GAI_STRERROR_PROTO
const char *
#else
char *
#endif
gai_strerror(int err)
{
        switch (err) {
        case EAI_NODATA:
                return ("no address associated with name");
        case EAI_MEMORY:
                return ("memory allocation failure.");
        case EAI_NONAME:
                return ("nodename nor servname provided, or not known");
        case EAI_FAMILY:
                return ("ai_family not supported");
        default:
                return ("unknown/invalid error.");
        }
}
#endif /* !HAVE_GAI_STRERROR */

#ifndef HAVE_FREEADDRINFO
void
freeaddrinfo(struct addrinfo *ai)
{
        struct addrinfo *next;

        for(; ai != NULL;) {
                next = ai->ai_next;
                free(ai);
                ai = next;
        }
}
#endif /* !HAVE_FREEADDRINFO */

#ifndef HAVE_GETADDRINFO
static struct
addrinfo *malloc_ai(int port, u_long addr, const struct addrinfo *hints)
{
        struct addrinfo *ai;

        ai = malloc(sizeof(*ai) + sizeof(struct sockaddr_in));
        if (ai == NULL)
                return (NULL);

        memset(ai, '\0', sizeof(*ai) + sizeof(struct sockaddr_in));

        ai->ai_addr = (struct sockaddr *)(ai + 1);
        /* XXX -- ssh doesn't use sa_len */
        ai->ai_addrlen = sizeof(struct sockaddr_in);
        ai->ai_addr->sa_family = ai->ai_family = AF_INET;

        ((struct sockaddr_in *)(ai)->ai_addr)->sin_port = port;
        ((struct sockaddr_in *)(ai)->ai_addr)->sin_addr.s_addr = addr;

        /* XXX: the following is not generally correct, but does what we want */
        if (hints->ai_socktype)
                ai->ai_socktype = hints->ai_socktype;
        else
                ai->ai_socktype = SOCK_STREAM;

        if (hints->ai_protocol)
                ai->ai_protocol = hints->ai_protocol;

        return (ai);
}

int
getaddrinfo(const char *hostname, const char *servname,
    const struct addrinfo *hints, struct addrinfo **res)
{
        struct hostent *hp;
        struct servent *sp;
        struct in_addr in;
        int i;
        long int port;
        u_long addr;

        port = 0;
        if (hints && hints->ai_family != AF_UNSPEC &&
            hints->ai_family != AF_INET)
                return (EAI_FAMILY);
        if (servname != NULL) {
                char *cp;

                port = strtol(servname, &cp, 10);
                if (port > 0 && port <= 65535 && *cp == '\0')
                        port = htons(port);
                else if ((sp = getservbyname(servname, NULL)) != NULL)
                        port = sp->s_port;
                else
                        port = 0;
        }

        if (hints && hints->ai_flags & AI_PASSIVE) {
                addr = htonl(0x00000000);
                if (hostname && inet_aton(hostname, &in) != 0)
                        addr = in.s_addr;
                *res = malloc_ai(port, addr, hints);
                if (*res == NULL)
                        return (EAI_MEMORY);
                return (0);
        }

        if (!hostname) {
                *res = malloc_ai(port, htonl(0x7f000001), hints);
                if (*res == NULL)
                        return (EAI_MEMORY);
                return (0);
        }

        if (inet_aton(hostname, &in)) {
                *res = malloc_ai(port, in.s_addr, hints);
                if (*res == NULL)
                        return (EAI_MEMORY);
                return (0);
        }

        /* Don't try DNS if AI_NUMERICHOST is set */
        if (hints && hints->ai_flags & AI_NUMERICHOST)
                return (EAI_NONAME);

        hp = gethostbyname(hostname);
        if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
                struct addrinfo *cur, *prev;

                cur = prev = *res = NULL;
                for (i = 0; hp->h_addr_list[i]; i++) {
                        struct in_addr *in = (struct in_addr *)hp->h_addr_list[i];

                        cur = malloc_ai(port, in->s_addr, hints);
                        if (cur == NULL) {
                                if (*res != NULL)
                                        freeaddrinfo(*res);
                                return (EAI_MEMORY);
                        }
                        if (prev)
                                prev->ai_next = cur;
                        else
                                *res = cur;

                        prev = cur;
                }
                return (0);
        }

        return (EAI_NODATA);
}
#endif /* !HAVE_GETADDRINFO */