201 lines
5.6 KiB
C
201 lines
5.6 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <string.h>
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#include "libutil.h"
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struct sockinet {
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u_char si_len;
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u_char si_family;
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u_short si_port;
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};
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int
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realhostname(char *host, size_t hsize, const struct in_addr *ip)
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{
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char trimmed[MAXHOSTNAMELEN];
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int result;
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struct hostent *hp;
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result = HOSTNAME_INVALIDADDR;
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hp = gethostbyaddr((const char *)ip, sizeof(*ip), AF_INET);
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if (hp != NULL) {
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strlcpy(trimmed, hp->h_name, sizeof(trimmed));
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trimdomain(trimmed, strlen(trimmed));
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if (strlen(trimmed) <= hsize) {
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char lookup[MAXHOSTNAMELEN];
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strlcpy(lookup, hp->h_name, sizeof(lookup));
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hp = gethostbyname(lookup);
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if (hp == NULL)
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result = HOSTNAME_INVALIDNAME;
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else for (; ; hp->h_addr_list++) {
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if (*hp->h_addr_list == NULL) {
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result = HOSTNAME_INCORRECTNAME;
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break;
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}
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if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) {
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strncpy(host, trimmed, hsize);
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return HOSTNAME_FOUND;
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}
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}
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}
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}
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strncpy(host, inet_ntoa(*ip), hsize);
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return result;
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}
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/*
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* struct sockaddr has very lax alignment requirements, since all its
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* members are char or equivalent. This is a problem when trying to
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* dereference a struct sockaddr_in6 * that was passed in as a struct
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* sockaddr *. Although we know (or trust) that the passed-in struct was
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* properly aligned, the compiler doesn't, and (rightly) complains. These
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* macros perform the cast in a way that the compiler will accept.
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*/
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#define SOCKADDR_IN6(p) ((struct sockaddr_in6 *)(void *)(p))
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#define SOCKADDR_IN(p) ((struct sockaddr_in *)(void *)(p))
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#define SOCKINET(p) ((struct sockinet *)(void *)(p))
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int
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realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen)
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{
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int result, error;
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char buf[NI_MAXHOST];
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#ifdef INET6
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struct sockaddr_in lsin;
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#endif
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result = HOSTNAME_INVALIDADDR;
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#ifdef INET6
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/* IPv4 mapped IPv6 addr consideraton, specified in rfc2373. */
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if (addr->sa_family == AF_INET6 &&
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addrlen == sizeof(struct sockaddr_in6) &&
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IN6_IS_ADDR_V4MAPPED(&SOCKADDR_IN6(addr)->sin6_addr)) {
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struct sockaddr_in6 *sin6;
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sin6 = SOCKADDR_IN6(addr);
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memset(&lsin, 0, sizeof(lsin));
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lsin.sin_len = sizeof(struct sockaddr_in);
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lsin.sin_family = AF_INET;
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lsin.sin_port = sin6->sin6_port;
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memcpy(&lsin.sin_addr, &sin6->sin6_addr.s6_addr[12],
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sizeof(struct in_addr));
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addr = (struct sockaddr *)&lsin;
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addrlen = lsin.sin_len;
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}
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#endif
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error = getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0,
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NI_NAMEREQD);
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if (error == 0) {
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struct addrinfo hints, *res, *ores;
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struct sockaddr *sa;
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memset(&hints, 0, sizeof(struct addrinfo));
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hints.ai_family = addr->sa_family;
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hints.ai_flags = AI_CANONNAME | AI_PASSIVE;
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hints.ai_socktype = SOCK_STREAM;
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error = getaddrinfo(buf, NULL, &hints, &res);
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if (error) {
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result = HOSTNAME_INVALIDNAME;
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goto numeric;
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}
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for (ores = res; ; res = res->ai_next) {
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if (res == NULL) {
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freeaddrinfo(ores);
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result = HOSTNAME_INCORRECTNAME;
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goto numeric;
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}
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sa = res->ai_addr;
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if (sa == NULL) {
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freeaddrinfo(ores);
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result = HOSTNAME_INCORRECTNAME;
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goto numeric;
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}
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if (sa->sa_len == addrlen &&
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sa->sa_family == addr->sa_family) {
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SOCKINET(sa)->si_port = SOCKINET(addr)->si_port;
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#ifdef INET6
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/*
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* XXX: sin6_socpe_id may not been
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* filled by DNS
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*/
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if (sa->sa_family == AF_INET6 &&
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SOCKADDR_IN6(sa)->sin6_scope_id == 0)
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SOCKADDR_IN6(sa)->sin6_scope_id =
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SOCKADDR_IN6(addr)->sin6_scope_id;
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#endif
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if (!memcmp(sa, addr, sa->sa_len)) {
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result = HOSTNAME_FOUND;
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if (ores->ai_canonname == NULL) {
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freeaddrinfo(ores);
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goto numeric;
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}
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strlcpy(buf, ores->ai_canonname,
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sizeof(buf));
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trimdomain(buf, hsize);
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if (strlen(buf) > hsize &&
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addr->sa_family == AF_INET) {
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freeaddrinfo(ores);
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goto numeric;
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}
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strncpy(host, buf, hsize);
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break;
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}
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}
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}
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freeaddrinfo(ores);
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} else {
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numeric:
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if (getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0,
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NI_NUMERICHOST) == 0)
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strncpy(host, buf, hsize);
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}
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return result;
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}
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