getnameinfo.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
* Copyright (C) 2009, 2011-2014, 2016 Internet Systems Consortium, Inc. ("ISC")
*
* 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 http://mozilla.org/MPL/2.0/.
*/
/* $Id$ */
/*! \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 <config.h>
#include <stdio.h>
#include <string.h>
#include <isc/netaddr.h>
#include <isc/print.h>
#include <isc/sockaddr.h>
#include <isc/util.h>
#include <dns/byaddr.h>
#include <dns/client.h>
#include <dns/fixedname.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/rdatastruct.h>
#include <dns/result.h>
#include <irs/context.h>
#include <irs/netdb.h>
#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)
int
getnameinfo(const struct sockaddr *sa, IRS_GETNAMEINFO_SOCKLEN_T salen,
char *host, IRS_GETNAMEINFO_BUFLEN_T hostlen,
char *serv, IRS_GETNAMEINFO_BUFLEN_T servlen,
IRS_GETNAMEINFO_FLAGS_T flags)
{
struct afd *afd = NULL;
struct servent *sp;
unsigned short port = 0;
#ifdef IRS_PLATFORM_HAVESALEN
size_t len;
#endif
int family, i;
const void *addr = NULL;
char *p;
#if 0
unsigned long v4a;
unsigned char pfx;
#endif
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
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:
INSIST(0);
}
proto = (flags & NI_DGRAM) ? "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);
strcpy(serv, numserv);
} else {
if ((strlen(sp->s_name) + 1) > servlen)
ERR(EAI_OVERFLOW);
strcpy(serv, sp->s_name);
}
#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 (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
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 (strlen(numaddr) + 1 > hostlen)
ERR(EAI_OVERFLOW);
strcpy(host, numaddr);
} else {
isc_netaddr_t netaddr;
dns_fixedname_t ptrfname;
dns_name_t *ptrname;
irs_context_t *irsctx = NULL;
dns_client_t *client;
isc_boolean_t found = ISC_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);
dns_fixedname_init(&ptrfname);
ptrname = dns_fixedname_name(&ptrfname);
iresult = dns_byaddr_createptrname2(&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,
DNS_CLIENTRESOPT_ALLOWRUN,
&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:
ERR(EAI_INSECUREDATA);
break;
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,
ISC_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 = ISC_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);
strcpy(host, numaddr);
}
}
result = SUCCESS;
cleanup:
return (result);
}