/* $NetBSD: getnameinfo.c,v 1.1.2.2 2024/02/24 13:07:18 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ /*! \file */ /* * 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. */ /** * getnameinfo() returns the hostname for the struct sockaddr sa which is * salen bytes long. The hostname is of length hostlen and is returned via * *host. The maximum length of the hostname is 1025 bytes: #NI_MAXHOST. * * The name of the service associated with the port number in sa is * returned in *serv. It is servlen bytes long. The maximum length of the * service name is #NI_MAXSERV - 32 bytes. * * The flags argument sets the following bits: * * \li #NI_NOFQDN: * A fully qualified domain name is not required for local hosts. * The local part of the fully qualified domain name is returned * instead. * * \li #NI_NUMERICHOST * Return the address in numeric form, as if calling inet_ntop(), * instead of a host name. * * \li #NI_NAMEREQD * A name is required. If the hostname cannot be found in the DNS * and this flag is set, a non-zero error code is returned. If the * hostname is not found and the flag is not set, the address is * returned in numeric form. * * \li #NI_NUMERICSERV * The service name is returned as a digit string representing the * port number. * * \li #NI_DGRAM * Specifies that the service being looked up is a datagram * service, and causes getservbyport() to be called with a second * argument of "udp" instead of its default of "tcp". This is * required for the few ports (512-514) that have different * services for UDP and TCP. * * \section getnameinfo_return Return Values * * getnameinfo() returns 0 on success or a non-zero error code if * an error occurs. * * \section getname_see See Also * * RFC3493, getservbyport(), * getnamebyaddr(). inet_ntop(). */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define SUCCESS 0 /*% afd structure definition */ static struct afd { int a_af; size_t a_addrlen; size_t a_socklen; } afdl[] = { /*! * First entry is linked last... */ { AF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in) }, { AF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6) }, { 0, 0, 0 }, }; /*! * The test against 0 is there to keep the Solaris compiler * from complaining about "end-of-loop code not reached". */ #define ERR(code) \ do { \ result = (code); \ if (result != 0) \ goto cleanup; \ } while (0) #ifdef _WIN32 int getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, DWORD hostlen, char *serv, DWORD servlen, int flags) { #else int getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t hostlen, char *serv, socklen_t servlen, int flags) { #endif struct afd *afd = NULL; struct servent *sp; unsigned short port = 0; #ifdef IRS_PLATFORM_HAVESALEN size_t len; #endif /* ifdef IRS_PLATFORM_HAVESALEN */ int family, i; const void *addr = NULL; char *p; #if 0 unsigned long v4a; unsigned char pfx; #endif /* if 0 */ char numserv[sizeof("65000")]; char numaddr[sizeof("abcd:abcd:abcd:abcd:abcd:abcd:255.255.255.255") + 1 + sizeof("4294967295")]; const char *proto; int result = SUCCESS; if (sa == NULL) { ERR(EAI_FAIL); } #ifdef IRS_PLATFORM_HAVESALEN len = sa->sa_len; if (len != salen) { ERR(EAI_FAIL); } #endif /* ifdef IRS_PLATFORM_HAVESALEN */ family = sa->sa_family; for (i = 0; afdl[i].a_af; i++) { if (afdl[i].a_af == family) { { afd = &afdl[i]; goto found; } } } ERR(EAI_FAMILY); found: if (salen != afd->a_socklen) { ERR(EAI_FAIL); } switch (family) { case AF_INET: port = ((const struct sockaddr_in *)sa)->sin_port; addr = &((const struct sockaddr_in *)sa)->sin_addr.s_addr; break; case AF_INET6: port = ((const struct sockaddr_in6 *)sa)->sin6_port; addr = ((const struct sockaddr_in6 *)sa)->sin6_addr.s6_addr; break; default: UNREACHABLE(); } proto = ((flags & NI_DGRAM) != 0) ? "udp" : "tcp"; if (serv == NULL || servlen == 0U) { /* * Caller does not want service. */ } else if ((flags & NI_NUMERICSERV) != 0 || (sp = getservbyport(port, proto)) == NULL) { snprintf(numserv, sizeof(numserv), "%d", ntohs(port)); if ((strlen(numserv) + 1) > servlen) { ERR(EAI_OVERFLOW); } strlcpy(serv, numserv, servlen); } else { if ((strlen(sp->s_name) + 1) > servlen) { ERR(EAI_OVERFLOW); } strlcpy(serv, sp->s_name, servlen); } #if 0 switch (sa->sa_family) { case AF_INET: v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr; if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) { flags |= NI_NUMERICHOST; } v4a >>= IN_CLASSA_NSHIFT; if (v4a == 0 || v4a == IN_LOOPBACKNET) { flags |= NI_NUMERICHOST; } break; case AF_INET6: pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0]; if (pfx == 0 || pfx == 0xfe || pfx == 0xff) { flags |= NI_NUMERICHOST; } break; } #endif /* if 0 */ if (host == NULL || hostlen == 0U) { /* * do nothing in this case. * in case you are wondering if "&&" is more correct than * "||" here: RFC3493 says that host == NULL or hostlen == 0 * means that the caller does not want the result. */ } else if ((flags & NI_NUMERICHOST) != 0) { if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) == NULL) { ERR(EAI_SYSTEM); } #if defined(IRS_HAVE_SIN6_SCOPE_ID) if (afd->a_af == AF_INET6 && ((const struct sockaddr_in6 *)sa)->sin6_scope_id) { char *p = numaddr + strlen(numaddr); const char *stringscope = NULL; #ifdef VENDOR_SPECIFIC /* * Vendors may want to add support for * non-numeric scope identifier. */ stringscope = foo; #endif /* ifdef VENDOR_SPECIFIC */ if (stringscope == NULL) { snprintf(p, sizeof(numaddr) - (p - numaddr), "%%%u", ((const struct sockaddr_in6 *)sa) ->sin6_scope_id); } else { snprintf(p, sizeof(numaddr) - (p - numaddr), "%%%s", stringscope); } } #endif /* if defined(IRS_HAVE_SIN6_SCOPE_ID) */ if (strlen(numaddr) + 1 > hostlen) { ERR(EAI_OVERFLOW); } strlcpy(host, numaddr, hostlen); } else { isc_netaddr_t netaddr; dns_fixedname_t ptrfname; dns_name_t *ptrname; irs_context_t *irsctx = NULL; dns_client_t *client; bool found = false; dns_namelist_t answerlist; dns_rdataset_t *rdataset; isc_region_t hostregion; char hoststr[1024]; /* is this enough? */ isc_result_t iresult; /* Get IRS context and the associated DNS client object */ iresult = irs_context_get(&irsctx); if (iresult != ISC_R_SUCCESS) { ERR(EAI_FAIL); } client = irs_context_getdnsclient(irsctx); /* Make query name */ isc_netaddr_fromsockaddr(&netaddr, (const isc_sockaddr_t *)sa); ptrname = dns_fixedname_initname(&ptrfname); iresult = dns_byaddr_createptrname(&netaddr, 0, ptrname); if (iresult != ISC_R_SUCCESS) { ERR(EAI_FAIL); } /* Get the PTR RRset */ ISC_LIST_INIT(answerlist); iresult = dns_client_resolve(client, ptrname, dns_rdataclass_in, dns_rdatatype_ptr, 0, &answerlist); switch (iresult) { case ISC_R_SUCCESS: /* * a 'non-existent' error is not necessarily fatal for * getnameinfo(). */ case DNS_R_NCACHENXDOMAIN: case DNS_R_NCACHENXRRSET: break; case DNS_R_SIGINVALID: case DNS_R_SIGEXPIRED: case DNS_R_SIGFUTURE: case DNS_R_KEYUNAUTHORIZED: case DNS_R_MUSTBESECURE: case DNS_R_COVERINGNSEC: case DNS_R_NOTAUTHORITATIVE: case DNS_R_NOVALIDKEY: case DNS_R_NOVALIDDS: case DNS_R_NOVALIDSIG: /* * Don't use ERR as GCC 7 wants to raise a * warning with ERR about possible falling * through which is impossible. */ result = EAI_INSECUREDATA; goto cleanup; default: ERR(EAI_FAIL); } /* Parse the answer for the hostname */ for (ptrname = ISC_LIST_HEAD(answerlist); ptrname != NULL; ptrname = ISC_LIST_NEXT(ptrname, link)) { for (rdataset = ISC_LIST_HEAD(ptrname->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (!dns_rdataset_isassociated(rdataset)) { continue; } if (rdataset->type != dns_rdatatype_ptr) { continue; } for (iresult = dns_rdataset_first(rdataset); iresult == ISC_R_SUCCESS; iresult = dns_rdataset_next(rdataset)) { dns_rdata_t rdata; dns_rdata_ptr_t rdata_ptr; isc_buffer_t b; dns_rdata_init(&rdata); dns_rdataset_current(rdataset, &rdata); dns_rdata_tostruct(&rdata, &rdata_ptr, NULL); isc_buffer_init(&b, hoststr, sizeof(hoststr)); iresult = dns_name_totext( &rdata_ptr.ptr, true, &b); dns_rdata_freestruct(&rdata_ptr); if (iresult == ISC_R_SUCCESS) { /* * We ignore the rest of the * answer. After all, * getnameinfo() can return * at most one hostname. */ found = true; isc_buffer_usedregion( &b, &hostregion); goto ptrfound; } } } } ptrfound: dns_client_freeresanswer(client, &answerlist); if (found) { if ((flags & NI_NOFQDN) != 0) { p = strchr(hoststr, '.'); if (p) { *p = '\0'; } } if (hostregion.length + 1 > hostlen) { ERR(EAI_OVERFLOW); } snprintf(host, hostlen, "%.*s", (int)hostregion.length, (char *)hostregion.base); } else { if ((flags & NI_NAMEREQD) != 0) { ERR(EAI_NONAME); } if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) == NULL) { ERR(EAI_SYSTEM); } if ((strlen(numaddr) + 1) > hostlen) { ERR(EAI_OVERFLOW); } strlcpy(host, numaddr, hostlen); } } result = SUCCESS; cleanup: return (result); }