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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include "libutil.h"
struct sockinet {
u_char si_len;
u_char si_family;
u_short si_port;
};
int
realhostname(char *host, size_t hsize, const struct in_addr *ip)
{
char trimmed[MAXHOSTNAMELEN];
int result;
struct hostent *hp;
result = HOSTNAME_INVALIDADDR;
hp = gethostbyaddr((const char *)ip, sizeof(*ip), AF_INET);
if (hp != NULL) {
strlcpy(trimmed, hp->h_name, sizeof(trimmed));
trimdomain(trimmed, strlen(trimmed));
if (strlen(trimmed) <= hsize) {
char lookup[MAXHOSTNAMELEN];
strlcpy(lookup, hp->h_name, sizeof(lookup));
hp = gethostbyname(lookup);
if (hp == NULL)
result = HOSTNAME_INVALIDNAME;
else for (; ; hp->h_addr_list++) {
if (*hp->h_addr_list == NULL) {
result = HOSTNAME_INCORRECTNAME;
break;
}
if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) {
strncpy(host, trimmed, hsize);
return HOSTNAME_FOUND;
}
}
}
}
strncpy(host, inet_ntoa(*ip), hsize);
return result;
}
/*
* struct sockaddr has very lax alignment requirements, since all its
* members are char or equivalent. This is a problem when trying to
* dereference a struct sockaddr_in6 * that was passed in as a struct
* sockaddr *. Although we know (or trust) that the passed-in struct was
* properly aligned, the compiler doesn't, and (rightly) complains. These
* macros perform the cast in a way that the compiler will accept.
*/
#define SOCKADDR_IN6(p) ((struct sockaddr_in6 *)(void *)(p))
#define SOCKADDR_IN(p) ((struct sockaddr_in *)(void *)(p))
#define SOCKINET(p) ((struct sockinet *)(void *)(p))
int
realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen)
{
int result, error;
char buf[NI_MAXHOST];
#ifdef INET6
struct sockaddr_in lsin;
#endif
result = HOSTNAME_INVALIDADDR;
#ifdef INET6
/* IPv4 mapped IPv6 addr consideraton, specified in rfc2373. */
if (addr->sa_family == AF_INET6 &&
addrlen == sizeof(struct sockaddr_in6) &&
IN6_IS_ADDR_V4MAPPED(&SOCKADDR_IN6(addr)->sin6_addr)) {
struct sockaddr_in6 *sin6;
sin6 = SOCKADDR_IN6(addr);
memset(&lsin, 0, sizeof(lsin));
lsin.sin_len = sizeof(struct sockaddr_in);
lsin.sin_family = AF_INET;
lsin.sin_port = sin6->sin6_port;
memcpy(&lsin.sin_addr, &sin6->sin6_addr.s6_addr[12],
sizeof(struct in_addr));
addr = (struct sockaddr *)&lsin;
addrlen = lsin.sin_len;
}
#endif
error = getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0,
NI_NAMEREQD);
if (error == 0) {
struct addrinfo hints, *res, *ores;
struct sockaddr *sa;
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = addr->sa_family;
hints.ai_flags = AI_CANONNAME | AI_PASSIVE;
hints.ai_socktype = SOCK_STREAM;
error = getaddrinfo(buf, NULL, &hints, &res);
if (error) {
result = HOSTNAME_INVALIDNAME;
goto numeric;
}
for (ores = res; ; res = res->ai_next) {
if (res == NULL) {
freeaddrinfo(ores);
result = HOSTNAME_INCORRECTNAME;
goto numeric;
}
sa = res->ai_addr;
if (sa == NULL) {
freeaddrinfo(ores);
result = HOSTNAME_INCORRECTNAME;
goto numeric;
}
if (sa->sa_len == addrlen &&
sa->sa_family == addr->sa_family) {
SOCKINET(sa)->si_port = SOCKINET(addr)->si_port;
#ifdef INET6
/*
* XXX: sin6_socpe_id may not been
* filled by DNS
*/
if (sa->sa_family == AF_INET6 &&
SOCKADDR_IN6(sa)->sin6_scope_id == 0)
SOCKADDR_IN6(sa)->sin6_scope_id =
SOCKADDR_IN6(addr)->sin6_scope_id;
#endif
if (!memcmp(sa, addr, sa->sa_len)) {
result = HOSTNAME_FOUND;
if (ores->ai_canonname == NULL) {
freeaddrinfo(ores);
goto numeric;
}
strlcpy(buf, ores->ai_canonname,
sizeof(buf));
trimdomain(buf, hsize);
if (strlen(buf) > hsize &&
addr->sa_family == AF_INET) {
freeaddrinfo(ores);
goto numeric;
}
strncpy(host, buf, hsize);
break;
}
}
}
freeaddrinfo(ores);
} else {
numeric:
if (getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0,
NI_NUMERICHOST) == 0)
strncpy(host, buf, hsize);
}
return result;
}
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