| /* $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. |
| */ |
| |
| #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 "resolv_private.h" |
| |
| /* Options. Leave them on. */ |
| #ifndef DEBUG |
| #define DEBUG |
| #endif |
| |
| // Queries will be padded to a multiple of this length when EDNS0 is active. |
| constexpr uint16_t kEdns0Padding = 128; |
| |
| // Defined in res_data.cpp |
| extern const char* _res_opcodes[]; |
| |
| /* |
| * 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; |
| |
| #ifdef DEBUG |
| if (statp->options & RES_DEBUG) |
| printf(";; res_nmkquery(%s, %s, %s, %s)\n", _res_opcodes[op], dname, p_class(cl), |
| p_type(type)); |
| #endif |
| /* |
| * Initialize header fields. |
| */ |
| if ((buf == NULL) || (buflen < HFIXEDSZ)) return (-1); |
| memset(buf, 0, HFIXEDSZ); |
| hp = (HEADER*) (void*) buf; |
| hp->id = htons(res_randomid()); |
| 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; |
| ns_put16(type, cp); |
| cp += INT16SZ; |
| ns_put16(cl, cp); |
| 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; |
| ns_put16(ns_t_null, cp); |
| cp += INT16SZ; |
| ns_put16(cl, cp); |
| cp += INT16SZ; |
| ns_put32(0, cp); |
| cp += INT32SZ; |
| ns_put16(0, cp); |
| 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 */ |
| ns_put16(type, cp); |
| cp += INT16SZ; |
| ns_put16(cl, cp); |
| cp += INT16SZ; |
| ns_put32(0, cp); |
| cp += INT32SZ; |
| ns_put16(datalen, cp); |
| 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; |
| |
| #ifdef DEBUG |
| if ((statp->options & RES_DEBUG) != 0U) printf(";; res_nopt()\n"); |
| #endif |
| |
| 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). |
| ns_put16(ns_t_opt, cp); /* TYPE */ |
| cp += INT16SZ; |
| if (anslen > 0xffff) anslen = 0xffff; |
| ns_put16(anslen, cp); /* CLASS = UDP payload size */ |
| cp += INT16SZ; |
| *cp++ = NOERROR; /* extended RCODE */ |
| *cp++ = 0; /* EDNS version */ |
| if (statp->options & RES_USE_DNSSEC) { |
| #ifdef DEBUG |
| if (statp->options & RES_DEBUG) printf(";; res_opt()... ENDS0 DNSSEC\n"); |
| #endif |
| flags |= NS_OPT_DNSSEC_OK; |
| } |
| ns_put16(flags, cp); |
| 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)); |
| ns_put16(padlen + 2 * INT16SZ, cp); /* RDLEN */ |
| cp += INT16SZ; |
| ns_put16(NS_OPT_PADDING, cp); /* OPTION-CODE */ |
| cp += INT16SZ; |
| ns_put16(padlen, cp); /* OPTION-LENGTH */ |
| cp += INT16SZ; |
| memset(cp, 0, padlen); |
| cp += padlen; |
| |
| hp->arcount = htons(ntohs(hp->arcount) + 1); |
| return (cp - buf); |
| } |