/*
 * 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.
 */

/*
 * "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator.
 *
 * Issues to be discussed:
 * - Thread safe-ness must be checked.
 * - Return values. There are nonstandard return values defined and used
 * in the source code. This is because RFC2133 is silent about which error
 * code must be returned for which situation.
 * - PF_UNSPEC case would be handled in getipnodebyname() with the AI_ALL flag.
 */

#if 0
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.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 <stdlib.h>
#include <stddef.h>
#include <ctype.h>
#include <unistd.h>

#include "addrinfo.h"
#endif

#if defined(__KAME__) && defined(ENABLE_IPV6)
# define FAITH
#endif

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

#ifdef FAITH
static int translate = NO;
static struct in6_addr faith_prefix = IN6ADDR_GAI_ANY_INIT;
#endif

static const char in_addrany[] = { 0, 0, 0, 0 };
static const char in6_addrany[] = {
 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static const char in_loopback[] = { 127, 0, 0, 1 };
static const char in6_loopback[] = {
 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
};

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

static struct gai_afd {
 int a_af;
 int a_addrlen;
 int a_socklen;
 int a_off;
 const char *a_addrany;
 const char *a_loopback;
} gai_afdl [] = {
#ifdef ENABLE_IPV6
#define N_INET6 0
 {PF_INET6, sizeof(struct in6_addr),
 sizeof(struct sockaddr_in6),
 offsetof(struct sockaddr_in6, sin6_addr),
 in6_addrany, in6_loopback},
#define N_INET 1
#else
#define N_INET 0
#endif
 {PF_INET, sizeof(struct in_addr),
 sizeof(struct sockaddr_in),
 offsetof(struct sockaddr_in, sin_addr),
 in_addrany, in_loopback},
 {0, 0, 0, 0, NULL, NULL},
};

#ifdef ENABLE_IPV6
#define PTON_MAX 16
#else
#define PTON_MAX 4
#endif

#ifndef IN_MULTICAST
#define IN_MULTICAST(i) (((i) & 0xf0000000U) == 0xe0000000U)
#endif

#ifndef IN_EXPERIMENTAL
#define IN_EXPERIMENTAL(i) (((i) & 0xe0000000U) == 0xe0000000U)
#endif

#ifndef IN_LOOPBACKNET
#define IN_LOOPBACKNET 127
#endif

static int get_name(const char *, struct gai_afd *,
 struct addrinfo **, char *, struct addrinfo *,
 int);
static int get_addr(const char *, int, struct addrinfo **,
 struct addrinfo *, int);
static int str_isnumber(const char *);

static const char * const ai_errlist[] = {
 "success.",
 "address family for hostname not supported.", /* EAI_ADDRFAMILY */
 "temporary failure in name resolution.", /* EAI_AGAIN */
 "invalid value for ai_flags.", /* EAI_BADFLAGS */
 "non-recoverable failure in name resolution.", /* EAI_FAIL */
 "ai_family not supported.", /* EAI_FAMILY */
 "memory allocation failure.", /* EAI_MEMORY */
 "no address associated with hostname.", /* EAI_NODATA */
 "hostname nor servname provided, or not known.",/* EAI_NONAME */
 "servname not supported for ai_socktype.", /* EAI_SERVICE */
 "ai_socktype not supported.", /* EAI_SOCKTYPE */
 "system error returned in errno.", /* EAI_SYSTEM */
 "invalid value for hints.", /* EAI_BADHINTS */
 "resolved protocol is unknown.", /* EAI_PROTOCOL */
 "unknown error.", /* EAI_MAX */
};

#define GET_CANONNAME(ai, str) \
if (pai->ai_flags & AI_CANONNAME) {\
 if (((ai)->ai_canonname = (char *)malloc(strlen(str) + 1)) != NULL) {\
 strcpy((ai)->ai_canonname, (str));\
 } else {\
 error = EAI_MEMORY;\
 goto free;\
 }\
}

#ifdef HAVE_SOCKADDR_SA_LEN
#define GET_AI(ai, gai_afd, addr, port) {\
 char *p;\
 if (((ai) = (struct addrinfo *)malloc(sizeof(struct addrinfo) +\
 ((gai_afd)->a_socklen)))\
 == NULL) goto free;\
 memcpy(ai, pai, sizeof(struct addrinfo));\
 (ai)->ai_addr = (struct sockaddr *)((ai) + 1);\
 memset((ai)->ai_addr, 0, (gai_afd)->a_socklen);\
 (ai)->ai_addr->sa_len = (ai)->ai_addrlen = (gai_afd)->a_socklen;\
 (ai)->ai_addr->sa_family = (ai)->ai_family = (gai_afd)->a_af;\
 ((struct sockinet *)(ai)->ai_addr)->si_port = port;\
 p = (char *)((ai)->ai_addr);\
 memcpy(p + (gai_afd)->a_off, (addr), (gai_afd)->a_addrlen);\
}
#else
#define GET_AI(ai, gai_afd, addr, port) {\
 char *p;\
 if (((ai) = (struct addrinfo *)malloc(sizeof(struct addrinfo) +\
 ((gai_afd)->a_socklen)))\
 == NULL) goto free;\
 memcpy(ai, pai, sizeof(struct addrinfo));\
 (ai)->ai_addr = (struct sockaddr *)((ai) + 1);\
 memset((ai)->ai_addr, 0, (gai_afd)->a_socklen);\
 (ai)->ai_addrlen = (gai_afd)->a_socklen;\
 (ai)->ai_addr->sa_family = (ai)->ai_family = (gai_afd)->a_af;\
 ((struct sockinet *)(ai)->ai_addr)->si_port = port;\
 p = (char *)((ai)->ai_addr);\
 memcpy(p + (gai_afd)->a_off, (addr), (gai_afd)->a_addrlen);\
}
#endif

#define ERR(err) { error = (err); goto bad; }

const char *
gai_strerror(int ecode)
{
 if (ecode < 0 || ecode > EAI_MAX)
 ecode = EAI_MAX;
 return ai_errlist[ecode];
}

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

 do {
 next = ai->ai_next;
 if (ai->ai_canonname)
 free(ai->ai_canonname);
 /* no need to free(ai->ai_addr) */
 free(ai);
 } while ((ai = next) != NULL);
}

static int
str_isnumber(const char *p)
{
 unsigned char *q = (unsigned char *)p;
 while (*q) {
 if (! isdigit(*q))
 return NO;
 q++;
 }
 return YES;
}

int
getaddrinfo(const char*hostname, const char*servname,
 const struct addrinfo *hints, struct addrinfo **res)
{
 struct addrinfo sentinel;
 struct addrinfo *top = NULL;
 struct addrinfo *cur;
 int i, error = 0;
 char pton[PTON_MAX];
 struct addrinfo ai;
 struct addrinfo *pai;
 u_short port;

#ifdef FAITH
 static int firsttime = 1;

 if (firsttime) {
 /* translator hack */
 {
 const char *q = getenv("GAI");
 if (q && inet_pton(AF_INET6, q, &faith_prefix) == 1)
 translate = YES;
 }
 firsttime = 0;
 }
#endif

 /* initialize file static vars */
 sentinel.ai_next = NULL;
 cur = &sentinel;
 pai = &ai;
 pai->ai_flags = 0;
 pai->ai_family = PF_UNSPEC;
 pai->ai_socktype = GAI_ANY;
 pai->ai_protocol = GAI_ANY;
 pai->ai_addrlen = 0;
 pai->ai_canonname = NULL;
 pai->ai_addr = NULL;
 pai->ai_next = NULL;
 port = GAI_ANY;

 if (hostname == NULL && servname == NULL)
 return EAI_NONAME;
 if (hints) {
 /* error check for hints */
 if (hints->ai_addrlen || hints->ai_canonname ||
 hints->ai_addr || hints->ai_next)
 ERR(EAI_BADHINTS); /* xxx */
 if (hints->ai_flags & ~AI_MASK)
 ERR(EAI_BADFLAGS);
 switch (hints->ai_family) {
 case PF_UNSPEC:
 case PF_INET:
#ifdef ENABLE_IPV6
 case PF_INET6:
#endif
 break;
 default:
 ERR(EAI_FAMILY);
 }
 memcpy(pai, hints, sizeof(*pai));
 switch (pai->ai_socktype) {
 case GAI_ANY:
 switch (pai->ai_protocol) {
 case GAI_ANY:
 break;
 case IPPROTO_UDP:
 pai->ai_socktype = SOCK_DGRAM;
 break;
 case IPPROTO_TCP:
 pai->ai_socktype = SOCK_STREAM;
 break;
 default:
 pai->ai_socktype = SOCK_RAW;
 break;
 }
 break;
 case SOCK_RAW:
 break;
 case SOCK_DGRAM:
 if (pai->ai_protocol != IPPROTO_UDP &&
 pai->ai_protocol != GAI_ANY)
 ERR(EAI_BADHINTS); /*xxx*/
 pai->ai_protocol = IPPROTO_UDP;
 break;
 case SOCK_STREAM:
 if (pai->ai_protocol != IPPROTO_TCP &&
 pai->ai_protocol != GAI_ANY)
 ERR(EAI_BADHINTS); /*xxx*/
 pai->ai_protocol = IPPROTO_TCP;
 break;
 default:
 ERR(EAI_SOCKTYPE);
 /* unreachable */
 }
 }

 /*
 * service port
 */
 if (servname) {
 if (str_isnumber(servname)) {
 if (pai->ai_socktype == GAI_ANY) {
 /* caller accept *GAI_ANY* socktype */
 pai->ai_socktype = SOCK_DGRAM;
 pai->ai_protocol = IPPROTO_UDP;
 }
 port = htons((u_short)atoi(servname));
 } else {
 struct servent *sp;
 const char *proto;

 proto = NULL;
 switch (pai->ai_socktype) {
 case GAI_ANY:
 proto = NULL;
 break;
 case SOCK_DGRAM:
 proto = "udp";
 break;
 case SOCK_STREAM:
 proto = "tcp";
 break;
 default:
 fprintf(stderr, "panic!\n");
 break;
 }
 if ((sp = getservbyname(servname, proto)) == NULL)
 ERR(EAI_SERVICE);
 port = sp->s_port;
 if (pai->ai_socktype == GAI_ANY) {
 if (strcmp(sp->s_proto, "udp") == 0) {
 pai->ai_socktype = SOCK_DGRAM;
 pai->ai_protocol = IPPROTO_UDP;
 } else if (strcmp(sp->s_proto, "tcp") == 0) {
 pai->ai_socktype = SOCK_STREAM;
 pai->ai_protocol = IPPROTO_TCP;
 } else
 ERR(EAI_PROTOCOL); /*xxx*/
 }
 }
 }

 /*
 * hostname == NULL.
 * passive socket -> anyaddr (0.0.0.0 or ::)
 * non-passive socket -> localhost (127.0.0.1 or ::1)
 */
 if (hostname == NULL) {
 struct gai_afd *gai_afd;

 for (gai_afd = &gai_afdl[0]; gai_afd->a_af; gai_afd++) {
 if (!(pai->ai_family == PF_UNSPEC
 || pai->ai_family == gai_afd->a_af)) {
 continue;
 }

 if (pai->ai_flags & AI_PASSIVE) {
 GET_AI(cur->ai_next, gai_afd, gai_afd->a_addrany, port);
 /* xxx meaningless?
 * GET_CANONNAME(cur->ai_next, "anyaddr");
 */
 } else {
 GET_AI(cur->ai_next, gai_afd, gai_afd->a_loopback,
 port);
 /* xxx meaningless?
 * GET_CANONNAME(cur->ai_next, "localhost");
 */
 }
 cur = cur->ai_next;
 }
 top = sentinel.ai_next;
 if (top)
 goto good;
 else
 ERR(EAI_FAMILY);
 }

 /* hostname as numeric name */
 for (i = 0; gai_afdl[i].a_af; i++) {
 if (inet_pton(gai_afdl[i].a_af, hostname, pton)) {
 u_long v4a;
#ifdef ENABLE_IPV6
 u_char pfx;
#endif

 switch (gai_afdl[i].a_af) {
 case AF_INET:
 v4a = ((struct in_addr *)pton)->s_addr;
 v4a = ntohl(v4a);
 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
 pai->ai_flags &= ~AI_CANONNAME;
 v4a >>= IN_CLASSA_NSHIFT;
 if (v4a == 0 || v4a == IN_LOOPBACKNET)
 pai->ai_flags &= ~AI_CANONNAME;
 break;
#ifdef ENABLE_IPV6
 case AF_INET6:
 pfx = ((struct in6_addr *)pton)->s6_addr[0];
 if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
 pai->ai_flags &= ~AI_CANONNAME;
 break;
#endif
 }

 if (pai->ai_family == gai_afdl[i].a_af ||
 pai->ai_family == PF_UNSPEC) {
 if (! (pai->ai_flags & AI_CANONNAME)) {
 GET_AI(top, &gai_afdl[i], pton, port);
 goto good;
 }
 /*
 * if AI_CANONNAME and if reverse lookup
 * fail, return ai anyway to pacify
 * calling application.
 *
 * XXX getaddrinfo() is a name->address
 * translation function, and it looks strange
 * that we do addr->name translation here.
 */
 get_name(pton, &gai_afdl[i], &top, pton, pai, port);
 goto good;
 } else
 ERR(EAI_FAMILY); /*xxx*/
 }
 }

 if (pai->ai_flags & AI_NUMERICHOST)
 ERR(EAI_NONAME);

 /* hostname as alphabetical name */
 error = get_addr(hostname, pai->ai_family, &top, pai, port);
 if (error == 0) {
 if (top) {
 good:
 *res = top;
 return SUCCESS;
 } else
 error = EAI_FAIL;
 }
 free:
 if (top)
 freeaddrinfo(top);
 bad:
 *res = NULL;
 return error;
}

static int
get_name(addr, gai_afd, res, numaddr, pai, port0)
 const char *addr;
 struct gai_afd *gai_afd;
 struct addrinfo **res;
 char *numaddr;
 struct addrinfo *pai;
 int port0;
{
 u_short port = port0 & 0xffff;
 struct hostent *hp;
 struct addrinfo *cur;
 int error = 0;
#ifdef ENABLE_IPV6
 int h_error;
#endif

#ifdef ENABLE_IPV6
 hp = getipnodebyaddr(addr, gai_afd->a_addrlen, gai_afd->a_af, &h_error);
#else
 hp = gethostbyaddr(addr, gai_afd->a_addrlen, AF_INET);
#endif
 if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
 GET_AI(cur, gai_afd, hp->h_addr_list[0], port);
 GET_CANONNAME(cur, hp->h_name);
 } else
 GET_AI(cur, gai_afd, numaddr, port);

#ifdef ENABLE_IPV6
 if (hp)
 freehostent(hp);
#endif
 *res = cur;
 return SUCCESS;
 free:
 if (cur)
 freeaddrinfo(cur);
#ifdef ENABLE_IPV6
 if (hp)
 freehostent(hp);
#endif
 /* bad: */
 *res = NULL;
 return error;
}

static int
get_addr(hostname, af, res, pai, port0)
 const char *hostname;
 int af;
 struct addrinfo **res;
 struct addrinfo *pai;
 int port0;
{
 u_short port = port0 & 0xffff;
 struct addrinfo sentinel;
 struct hostent *hp;
 struct addrinfo *top, *cur;
 struct gai_afd *gai_afd;
 int i, error = 0, h_error;
 char *ap;

 top = NULL;
 sentinel.ai_next = NULL;
 cur = &sentinel;
#ifdef ENABLE_IPV6
 if (af == AF_UNSPEC) {
 hp = getipnodebyname(hostname, AF_INET6,
 AI_ADDRCONFIG|AI_ALL|AI_V4MAPPED, &h_error);
 } else
 hp = getipnodebyname(hostname, af, AI_ADDRCONFIG, &h_error);
#else
 hp = gethostbyname(hostname);
 h_error = h_errno;
#endif
 if (hp == NULL) {
 switch (h_error) {
 case HOST_NOT_FOUND:
 case NO_DATA:
 error = EAI_NODATA;
 break;
 case TRY_AGAIN:
 error = EAI_AGAIN;
 break;
 case NO_RECOVERY:
 default:
 error = EAI_FAIL;
 break;
 }
 goto free;
 }

 if ((hp->h_name == NULL) || (hp->h_name[0] == 0) ||
 (hp->h_addr_list[0] == NULL)) {
 error = EAI_FAIL;
 goto free;
 }

 for (i = 0; (ap = hp->h_addr_list[i]) != NULL; i++) {
 switch (af) {
#ifdef ENABLE_IPV6
 case AF_INET6:
 gai_afd = &gai_afdl[N_INET6];
 break;
#endif
#ifndef ENABLE_IPV6
 default: /* AF_UNSPEC */
#endif
 case AF_INET:
 gai_afd = &gai_afdl[N_INET];
 break;
#ifdef ENABLE_IPV6
 default: /* AF_UNSPEC */
 if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
 ap += sizeof(struct in6_addr) -
 sizeof(struct in_addr);
 gai_afd = &gai_afdl[N_INET];
 } else
 gai_afd = &gai_afdl[N_INET6];
 break;
#endif
 }
#ifdef FAITH
 if (translate && gai_afd->a_af == AF_INET) {
 struct in6_addr *in6;

 GET_AI(cur->ai_next, &gai_afdl[N_INET6], ap, port);
 in6 = &((struct sockaddr_in6 *)cur->ai_next->ai_addr)->sin6_addr;
 memcpy(&in6->s6_addr32[0], &faith_prefix,
 sizeof(struct in6_addr) - sizeof(struct in_addr));
 memcpy(&in6->s6_addr32[3], ap, sizeof(struct in_addr));
 } else
#endif /* FAITH */
 GET_AI(cur->ai_next, gai_afd, ap, port);
 if (cur == &sentinel) {
 top = cur->ai_next;
 GET_CANONNAME(top, hp->h_name);
 }
 cur = cur->ai_next;
 }
#ifdef ENABLE_IPV6
 freehostent(hp);
#endif
 *res = top;
 return SUCCESS;
 free:
 if (top)
 freeaddrinfo(top);
#ifdef ENABLE_IPV6
 if (hp)
 freehostent(hp);
#endif
/* bad: */
 *res = NULL;
 return error;
}