| /* $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" // res_state |
| |
| // 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 |
| const uint8_t* data, // resource record data |
| int datalen, // length of data |
| uint8_t* buf, // buffer to put query |
| int buflen, // size of buffer |
| int netcontext_flags) { |
| HEADER* hp; |
| uint8_t *cp, *ep; |
| int n; |
| uint8_t *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 = true; |
| hp->ad = (netcontext_flags & NET_CONTEXT_FLAG_USE_DNS_OVER_TLS) != 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 */ |
| uint8_t* buf, /* buffer to put query */ |
| int buflen, /* size of buffer */ |
| int anslen) /* UDP answer buffer size */ |
| { |
| HEADER* hp; |
| uint8_t *cp, *ep; |
| uint16_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->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) + 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); |
| } |
