244 lines
9.6 KiB
C++
244 lines
9.6 KiB
C++
/* $NetBSD: res_mkquery.c,v 1.6 2006/01/24 17:40:32 christos Exp $ */
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/*
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* Copyright (c) 1985, 1993
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* The Regents of the University of California. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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/*
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#define LOG_TAG "resolv"
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#include <algorithm> // std::min()
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#include <arpa/nameser.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <string.h>
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#include <android-base/logging.h>
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#include <netd_resolv/resolv.h> // NET_CONTEXT_FLAG_USE_DNS_OVER_TLS
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#include "res_comp.h"
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#include "res_debug.h"
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#include "resolv_private.h" // ResState*
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// Queries will be padded to a multiple of this length when EDNS0 is active.
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constexpr uint16_t kEdns0Padding = 128;
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extern const char* const _res_opcodes[] = {
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"QUERY", "IQUERY", "CQUERYM", "CQUERYU", /* experimental */
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"NOTIFY", /* experimental */
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"UPDATE", "6", "7", "8", "9", "10",
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"11", "12", "13", "ZONEINIT", "ZONEREF",
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};
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// Form all types of queries. Returns the size of the result or -1.
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int res_nmkquery(int op, // opcode of query
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const char* dname, // domain name
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int cl, int type, // class and type of query
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std::span<const uint8_t> data, // resource record data
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std::span<uint8_t> buf, // buffer to put query
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int netcontext_flags) {
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HEADER* hp;
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uint8_t *cp, *ep;
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int n;
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uint8_t *dnptrs[20], **dpp, **lastdnptr;
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LOG(DEBUG) << __func__ << ": (" << _res_opcodes[op] << ", " << p_class(cl) << ", "
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<< p_type(type) << ")";
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/*
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* Initialize header fields.
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*/
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if (buf.empty() || (buf.size() < HFIXEDSZ)) return (-1);
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memset(buf.data(), 0, HFIXEDSZ);
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hp = (HEADER*)(void*)buf.data();
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hp->id = htons(arc4random_uniform(65536));
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hp->opcode = op;
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hp->rd = true;
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hp->ad = (netcontext_flags & NET_CONTEXT_FLAG_USE_DNS_OVER_TLS) != 0U;
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hp->rcode = NOERROR;
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cp = buf.data() + HFIXEDSZ;
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ep = buf.data() + buf.size();
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dpp = dnptrs;
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*dpp++ = buf.data();
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*dpp++ = NULL;
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lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
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/*
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* perform opcode specific processing
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*/
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switch (op) {
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case QUERY:
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[[fallthrough]];
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case NS_NOTIFY_OP:
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if (ep - cp < QFIXEDSZ) return (-1);
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if ((n = dn_comp(dname, cp, ep - cp - QFIXEDSZ, dnptrs, lastdnptr)) < 0) return (-1);
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cp += n;
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*reinterpret_cast<uint16_t*>(cp) = htons(type);
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cp += INT16SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(cl);
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cp += INT16SZ;
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hp->qdcount = htons(1);
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if (op == QUERY || data.empty()) break;
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/*
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* Make an additional record for completion domain.
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*/
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if ((ep - cp) < RRFIXEDSZ) return (-1);
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n = dn_comp((const char*)data.data(), cp, ep - cp - RRFIXEDSZ, dnptrs, lastdnptr);
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if (n < 0) return (-1);
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cp += n;
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*reinterpret_cast<uint16_t*>(cp) = htons(ns_t_null);
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cp += INT16SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(cl);
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cp += INT16SZ;
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*reinterpret_cast<uint32_t*>(cp) = htonl(0);
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cp += INT32SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(0);
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cp += INT16SZ;
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hp->arcount = htons(1);
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break;
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case IQUERY:
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/*
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* Initialize answer section
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*/
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if (ep - cp < 1 + RRFIXEDSZ + data.size()) return (-1);
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*cp++ = '\0'; /* no domain name */
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*reinterpret_cast<uint16_t*>(cp) = htons(type);
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cp += INT16SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(cl);
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cp += INT16SZ;
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*reinterpret_cast<uint32_t*>(cp) = htonl(0);
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cp += INT32SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(data.size());
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cp += INT16SZ;
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if (data.size()) {
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memcpy(cp, data.data(), data.size());
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cp += data.size();
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}
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hp->ancount = htons(1);
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break;
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default:
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return (-1);
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}
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return (cp - buf.data());
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}
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int res_nopt(ResState* statp, int n0, /* current offset in buffer */
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std::span<uint8_t> buf, /* buffer to put query */
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int anslen) /* UDP answer buffer size */
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{
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HEADER* hp = reinterpret_cast<HEADER*>(buf.data());
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uint8_t *cp, *ep;
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uint16_t flags = 0;
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LOG(DEBUG) << __func__;
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cp = buf.data() + n0;
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ep = buf.data() + buf.size();
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if ((ep - cp) < 1 + RRFIXEDSZ) return (-1);
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*cp++ = 0; /* "." */
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// Attach OPT pseudo-RR, as documented in RFC2671 (EDNS0).
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*reinterpret_cast<uint16_t*>(cp) = htons(ns_t_opt); /* TYPE */
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cp += INT16SZ;
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if (anslen > 0xffff) anslen = 0xffff;
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*reinterpret_cast<uint16_t*>(cp) = htons(anslen); /* CLASS = UDP payload size */
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cp += INT16SZ;
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*cp++ = NOERROR; /* extended RCODE */
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*cp++ = 0; /* EDNS version */
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if (statp->netcontext_flags & NET_CONTEXT_FLAG_USE_DNS_OVER_TLS) {
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LOG(DEBUG) << __func__ << ": ENDS0 DNSSEC";
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flags |= NS_OPT_DNSSEC_OK;
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}
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*reinterpret_cast<uint16_t*>(cp) = htons(flags);
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cp += INT16SZ;
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// EDNS0 padding
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const uint16_t minlen = static_cast<uint16_t>(cp - buf.data()) + 3 * INT16SZ;
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const uint16_t extra = minlen % kEdns0Padding;
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uint16_t padlen = (kEdns0Padding - extra) % kEdns0Padding;
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if (minlen > buf.size()) {
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return -1;
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}
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padlen = std::min(padlen, static_cast<uint16_t>(buf.size() - minlen));
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*reinterpret_cast<uint16_t*>(cp) = htons(padlen + 2 * INT16SZ); /* RDLEN */
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cp += INT16SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(NS_OPT_PADDING); /* OPTION-CODE */
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cp += INT16SZ;
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*reinterpret_cast<uint16_t*>(cp) = htons(padlen); /* OPTION-LENGTH */
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cp += INT16SZ;
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memset(cp, 0, padlen);
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cp += padlen;
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hp->arcount = htons(ntohs(hp->arcount) + 1);
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return (cp - buf.data());
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}
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