/* $NetBSD: res_mkquery.c,v 1.6 2006/01/24 17:40:32 christos Exp $ */
/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
*/
/*
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#define LOG_TAG "res_mkquery"
#include <algorithm> // std::min()
#include <arpa/nameser.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <android-base/logging.h>
#include "resolv_private.h"
// Queries will be padded to a multiple of this length when EDNS0 is active.
constexpr uint16_t kEdns0Padding = 128;
extern const char* const _res_opcodes[] = {
"QUERY", "IQUERY", "CQUERYM", "CQUERYU", /* experimental */
"NOTIFY", /* experimental */
"UPDATE", "6", "7", "8", "9", "10",
"11", "12", "13", "ZONEINIT", "ZONEREF",
};
/*
* Form all types of queries.
* Returns the size of the result or -1.
*/
int res_nmkquery(res_state statp, int op, /* opcode of query */
const char* dname, /* domain name */
int cl, int type, /* class and type of query */
const u_char* data, /* resource record data */
int datalen, /* length of data */
const u_char* /*newrr_in*/, /* new rr for modify or append */
u_char* buf, /* buffer to put query */
int buflen) /* size of buffer */
{
HEADER* hp;
u_char *cp, *ep;
int n;
u_char *dnptrs[20], **dpp, **lastdnptr;
LOG(DEBUG) << __func__ << ": (" << _res_opcodes[op] << ", " << p_class(cl) << ", "
<< p_type(type) << ")";
/*
* Initialize header fields.
*/
if ((buf == NULL) || (buflen < HFIXEDSZ)) return (-1);
memset(buf, 0, HFIXEDSZ);
hp = (HEADER*) (void*) buf;
hp->id = htons(arc4random_uniform(65536));
hp->opcode = op;
hp->rd = (statp->options & RES_RECURSE) != 0U;
hp->ad = (statp->options & RES_USE_DNSSEC) != 0U;
hp->rcode = NOERROR;
cp = buf + HFIXEDSZ;
ep = buf + buflen;
dpp = dnptrs;
*dpp++ = buf;
*dpp++ = NULL;
lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
/*
* perform opcode specific processing
*/
switch (op) {
case QUERY:
[[fallthrough]];
case NS_NOTIFY_OP:
if (ep - cp < QFIXEDSZ) return (-1);
if ((n = dn_comp(dname, cp, ep - cp - QFIXEDSZ, dnptrs, lastdnptr)) < 0) return (-1);
cp += n;
*reinterpret_cast<uint16_t*>(cp) = htons(type);
cp += INT16SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(cl);
cp += INT16SZ;
hp->qdcount = htons(1);
if (op == QUERY || data == NULL) break;
/*
* Make an additional record for completion domain.
*/
if ((ep - cp) < RRFIXEDSZ) return (-1);
n = dn_comp((const char*) data, cp, ep - cp - RRFIXEDSZ, dnptrs, lastdnptr);
if (n < 0) return (-1);
cp += n;
*reinterpret_cast<uint16_t*>(cp) = htons(ns_t_null);
cp += INT16SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(cl);
cp += INT16SZ;
*reinterpret_cast<uint32_t*>(cp) = htonl(0);
cp += INT32SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(0);
cp += INT16SZ;
hp->arcount = htons(1);
break;
case IQUERY:
/*
* Initialize answer section
*/
if (ep - cp < 1 + RRFIXEDSZ + datalen) return (-1);
*cp++ = '\0'; /* no domain name */
*reinterpret_cast<uint16_t*>(cp) = htons(type);
cp += INT16SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(cl);
cp += INT16SZ;
*reinterpret_cast<uint32_t*>(cp) = htonl(0);
cp += INT32SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(datalen);
cp += INT16SZ;
if (datalen) {
memcpy(cp, data, (size_t) datalen);
cp += datalen;
}
hp->ancount = htons(1);
break;
default:
return (-1);
}
return (cp - buf);
}
int res_nopt(res_state statp, int n0, /* current offset in buffer */
u_char* buf, /* buffer to put query */
int buflen, /* size of buffer */
int anslen) /* UDP answer buffer size */
{
HEADER* hp;
u_char *cp, *ep;
u_int16_t flags = 0;
LOG(DEBUG) << __func__;
hp = (HEADER*) (void*) buf;
cp = buf + n0;
ep = buf + buflen;
if ((ep - cp) < 1 + RRFIXEDSZ) return (-1);
*cp++ = 0; /* "." */
// Attach OPT pseudo-RR, as documented in RFC2671 (EDNS0).
*reinterpret_cast<uint16_t*>(cp) = htons(ns_t_opt); /* TYPE */
cp += INT16SZ;
if (anslen > 0xffff) anslen = 0xffff;
*reinterpret_cast<uint16_t*>(cp) = htons(anslen); /* CLASS = UDP payload size */
cp += INT16SZ;
*cp++ = NOERROR; /* extended RCODE */
*cp++ = 0; /* EDNS version */
if (statp->options & RES_USE_DNSSEC) {
LOG(DEBUG) << __func__ << ": ENDS0 DNSSEC";
flags |= NS_OPT_DNSSEC_OK;
}
*reinterpret_cast<uint16_t*>(cp) = htons(flags);
cp += INT16SZ;
// EDNS0 padding
const uint16_t minlen = static_cast<uint16_t>(cp - buf) + 3 * INT16SZ;
const uint16_t extra = minlen % kEdns0Padding;
uint16_t padlen = (kEdns0Padding - extra) % kEdns0Padding;
if (minlen > buflen) {
return -1;
}
padlen = std::min(padlen, static_cast<uint16_t>(buflen - minlen));
*reinterpret_cast<uint16_t*>(cp) = htons(padlen + 2 * INT16SZ); /* RDLEN */
cp += INT16SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(NS_OPT_PADDING); /* OPTION-CODE */
cp += INT16SZ;
*reinterpret_cast<uint16_t*>(cp) = htons(padlen); /* OPTION-LENGTH */
cp += INT16SZ;
memset(cp, 0, padlen);
cp += padlen;
hp->arcount = htons(ntohs(hp->arcount) + 1);
return (cp - buf);
}