/*
 * Mar  8, 2000 by Hajimu UMEMOTO <ume@mahoroba.org>
 * $Id: getaddrinfo.c,v 1.13 2005/08/27 16:33:10 ume Exp $
 *
 * This module is besed on ssh-1.2.27-IPv6-1.5 written by
 * KIKUCHI Takahiro <kick@kyoto.wide.ad.jp>
 */
/*
 * fake library for ssh
 *
 * This file includes getaddrinfo(), freeaddrinfo() and gai_strerror().
 * These funtions are defined in rfc2133.
 *
 * But these functions are not implemented correctly. The minimum subset
 * is implemented for ssh use only. For exapmle, this routine assumes
 * that ai_family is AF_INET. Don't use it for another purpose.
 * 
 * In the case not using 'configure --enable-ipv6', this getaddrinfo.c
 * will be used if you have broken getaddrinfo or no getaddrinfo.
 */

#include <sys/param.h>
#include "gai.h"

static struct addrinfo *
malloc_ai(int port, u_long addr, int socktype, int proto)
{
    struct addrinfo *ai;

    ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) +
				   sizeof(struct sockaddr_in));
    if (ai) {
	memset(ai, 0, sizeof(struct addrinfo) + 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);
#ifdef HAVE_SOCKADDR_SA_LEN
	ai->ai_addr->sa_len = sizeof(struct sockaddr_in);
#endif
	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;
	ai->ai_socktype = socktype;
	ai->ai_protocol = proto;
	return ai;
    } else {
	return NULL;
    }
}

char *
gai_strerror(int ecode)
{
    switch (ecode) {
    case EAI_MEMORY:
	return "memory allocation failure.";
    case EAI_FAMILY:
	return "ai_family not supported.";
    case EAI_NONAME:
	return "hostname nor servname provided, or not known.";
    case EAI_SERVICE:
	return "servname not supported for ai_socktype.";
    default:
	return "unknown error.";
    }
}

void
freeaddrinfo(struct addrinfo *ai)
{
    struct addrinfo *next;

    if (ai->ai_canonname)
	free(ai->ai_canonname);
    do {
	next = ai->ai_next;
	free(ai);
    } while ((ai = next) != NULL);
}

int
getaddrinfo(const char *hostname, const char *servname,
	    const struct addrinfo *hints, struct addrinfo **res)
{
    struct addrinfo *cur, *prev = NULL;
    struct hostent *hp;
    struct in_addr in;
    int i, port = 0, socktype, proto;

    if (hints && hints->ai_family != PF_INET && hints->ai_family != PF_UNSPEC)
	return EAI_FAMILY;

    socktype = (hints && hints->ai_socktype) ? hints->ai_socktype
					     : SOCK_STREAM;
    if (hints && hints->ai_protocol)
	proto = hints->ai_protocol;
    else {
	switch (socktype) {
	case SOCK_DGRAM:
	    proto = IPPROTO_UDP;
	    break;
	case SOCK_STREAM:
	    proto = IPPROTO_TCP;
	    break;
	default:
	    proto = 0;
	    break;
	}
    }
    if (servname) {
	if (isdigit((int)*servname))
	    port = htons(atoi(servname));
	else {
	    struct servent *se;
	    char *pe_proto;

	    if (hints && hints->ai_flags & AI_NUMERICSERV)
		    return EAI_NONAME;
	    switch (socktype) {
	    case SOCK_DGRAM:
		pe_proto = "udp";
		break;
	    case SOCK_STREAM:
		pe_proto = "tcp";
		break;
	    default:
		pe_proto = NULL;
		break;
	    }
	    if ((se = getservbyname(servname, pe_proto)) == NULL)
		return EAI_SERVICE;
	    port = se->s_port;
	}
    }
    if (!hostname) {
	if (hints && hints->ai_flags & AI_PASSIVE)
	    *res = malloc_ai(port, htonl(0x00000000), socktype, proto);
	else
	    *res = malloc_ai(port, htonl(0x7f000001), socktype, proto);
	if (*res)
	    return 0;
	else
	    return EAI_MEMORY;
    }
    if (inet_aton(hostname, &in)) {
	*res = malloc_ai(port, in.s_addr, socktype, proto);
	if (*res)
	    return 0;
	else
	    return EAI_MEMORY;
    }
    if (hints && hints->ai_flags & AI_NUMERICHOST)
	return EAI_NONAME;
    if ((hp = gethostbyname(hostname)) &&
	hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
	for (i = 0; hp->h_addr_list[i]; i++) {
	    if ((cur = malloc_ai(port,
				((struct in_addr *)hp->h_addr_list[i])->s_addr,
				socktype, proto)) == NULL) {
		if (*res)
		    freeaddrinfo(*res);
		return EAI_MEMORY;
	    }
	    if (prev)
		prev->ai_next = cur;
	    else
		*res = cur;
	    prev = cur;
	}
	if (hints && hints->ai_flags & AI_CANONNAME && *res) {
	    if (((*res)->ai_canonname = strdup(hp->h_name)) == NULL) {
		freeaddrinfo(*res);
		return EAI_MEMORY;
	    }
	}
	return 0;
    }
    return EAI_NONAME;
}