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/* $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 "resolv"
#include <algorithm> // std::min()
#include <arpa/nameser.h>
#include <netdb.h>
#include <netinet/in.h>
#include <string.h>
#include <android-base/logging.h>
#include <netd_resolv/resolv.h> // NET_CONTEXT_FLAG_USE_DNS_OVER_TLS
#include "res_comp.h"
#include "res_debug.h"
#include "resolv_private.h" // ResState*
// 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(int op, // opcode of query
const char* dname, // domain name
int cl, int type, // class and type of query
std::span<const uint8_t> data, // resource record data
std::span<uint8_t> buf, // buffer to put query
int netcontext_flags) {
HEADER* hp;
uint8_t *cp, *ep;
int n;
uint8_t *dnptrs[20], **dpp, **lastdnptr;
LOG(INFO) << __func__ << ": (" << _res_opcodes[op] << ", " << p_class(cl) << ", "
<< p_type(type) << ")";
/*
* Initialize header fields.
*/
if (buf.empty() || (buf.size() < HFIXEDSZ)) return (-1);
memset(buf.data(), 0, HFIXEDSZ);
hp = (HEADER*)(void*)buf.data();
hp->id = htons(arc4random_uniform(65536));
hp->opcode = op;
hp->rd = true;
hp->ad = (netcontext_flags & NET_CONTEXT_FLAG_USE_DNS_OVER_TLS) != 0U;
hp->rcode = NOERROR;
cp = buf.data() + HFIXEDSZ;
ep = buf.data() + buf.size();
dpp = dnptrs;
*dpp++ = buf.data();
*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.empty()) break;
/*
* Make an additional record for completion domain.
*/
if ((ep - cp) < RRFIXEDSZ) return (-1);
n = dn_comp((const char*)data.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 < static_cast<ptrdiff_t>(1 + RRFIXEDSZ + data.size())) 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(data.size());
cp += INT16SZ;
if (data.size()) {
memcpy(cp, data.data(), data.size());
cp += data.size();
}
hp->ancount = htons(1);
break;
default:
return (-1);
}
return (cp - buf.data());
}
int res_nopt(ResState* statp, int n0, /* current offset in buffer */
std::span<uint8_t> buf, /* buffer to put query */
int anslen) /* UDP answer buffer size */
{
HEADER* hp = reinterpret_cast<HEADER*>(buf.data());
uint8_t *cp, *ep;
uint16_t flags = 0;
LOG(DEBUG) << __func__;
cp = buf.data() + n0;
ep = buf.data() + buf.size();
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->netcontext_flags & NET_CONTEXT_FLAG_USE_DNS_OVER_TLS) {
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.data()) + 3 * INT16SZ;
const uint16_t extra = minlen % kEdns0Padding;
uint16_t padlen = (kEdns0Padding - extra) % kEdns0Padding;
if (minlen > buf.size()) {
return -1;
}
padlen = std::min(padlen, static_cast<uint16_t>(buf.size() - 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.data());
}
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