1 /* $NetBSD: res_mkquery.c,v 1.6 2006/01/24 17:40:32 christos Exp $ */
2
3 /*
4 * Copyright (c) 1985, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 /*
37 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
38 *
39 * Permission to use, copy, modify, and distribute this software for any
40 * purpose with or without fee is hereby granted, provided that the above
41 * copyright notice and this permission notice appear in all copies, and that
42 * the name of Digital Equipment Corporation not be used in advertising or
43 * publicity pertaining to distribution of the document or software without
44 * specific, written prior permission.
45 *
46 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
47 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
48 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
49 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
50 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
51 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
52 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
53 * SOFTWARE.
54 */
55
56 /*
57 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
58 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
59 *
60 * Permission to use, copy, modify, and distribute this software for any
61 * purpose with or without fee is hereby granted, provided that the above
62 * copyright notice and this permission notice appear in all copies.
63 *
64 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
65 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
66 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
67 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
68 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
69 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
70 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
71 */
72
73 #define LOG_TAG "res_mkquery"
74
75 #include <algorithm> // std::min()
76
77 #include <arpa/nameser.h>
78 #include <netdb.h>
79 #include <netinet/in.h>
80 #include <stdio.h>
81 #include <string.h>
82 #include <sys/types.h>
83
84 #include <android-base/logging.h>
85
86 #include "resolv_private.h"
87
88 // Queries will be padded to a multiple of this length when EDNS0 is active.
89 constexpr uint16_t kEdns0Padding = 128;
90
91 extern const char* const _res_opcodes[] = {
92 "QUERY", "IQUERY", "CQUERYM", "CQUERYU", /* experimental */
93 "NOTIFY", /* experimental */
94 "UPDATE", "6", "7", "8", "9", "10",
95 "11", "12", "13", "ZONEINIT", "ZONEREF",
96 };
97
98 /*
99 * Form all types of queries.
100 * Returns the size of the result or -1.
101 */
res_nmkquery(res_state statp,int op,const char * dname,int cl,int type,const u_char * data,int datalen,const u_char *,u_char * buf,int buflen)102 int res_nmkquery(res_state statp, int op, /* opcode of query */
103 const char* dname, /* domain name */
104 int cl, int type, /* class and type of query */
105 const u_char* data, /* resource record data */
106 int datalen, /* length of data */
107 const u_char* /*newrr_in*/, /* new rr for modify or append */
108 u_char* buf, /* buffer to put query */
109 int buflen) /* size of buffer */
110 {
111 HEADER* hp;
112 u_char *cp, *ep;
113 int n;
114 u_char *dnptrs[20], **dpp, **lastdnptr;
115
116 LOG(DEBUG) << __func__ << ": (" << _res_opcodes[op] << ", " << p_class(cl) << ", "
117 << p_type(type) << ")";
118
119 /*
120 * Initialize header fields.
121 */
122 if ((buf == NULL) || (buflen < HFIXEDSZ)) return (-1);
123 memset(buf, 0, HFIXEDSZ);
124 hp = (HEADER*) (void*) buf;
125 hp->id = htons(arc4random_uniform(65536));
126 hp->opcode = op;
127 hp->rd = (statp->options & RES_RECURSE) != 0U;
128 hp->ad = (statp->options & RES_USE_DNSSEC) != 0U;
129 hp->rcode = NOERROR;
130 cp = buf + HFIXEDSZ;
131 ep = buf + buflen;
132 dpp = dnptrs;
133 *dpp++ = buf;
134 *dpp++ = NULL;
135 lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
136 /*
137 * perform opcode specific processing
138 */
139 switch (op) {
140 case QUERY:
141 [[fallthrough]];
142 case NS_NOTIFY_OP:
143 if (ep - cp < QFIXEDSZ) return (-1);
144 if ((n = dn_comp(dname, cp, ep - cp - QFIXEDSZ, dnptrs, lastdnptr)) < 0) return (-1);
145 cp += n;
146 *reinterpret_cast<uint16_t*>(cp) = htons(type);
147 cp += INT16SZ;
148 *reinterpret_cast<uint16_t*>(cp) = htons(cl);
149 cp += INT16SZ;
150 hp->qdcount = htons(1);
151 if (op == QUERY || data == NULL) break;
152 /*
153 * Make an additional record for completion domain.
154 */
155 if ((ep - cp) < RRFIXEDSZ) return (-1);
156 n = dn_comp((const char*) data, cp, ep - cp - RRFIXEDSZ, dnptrs, lastdnptr);
157 if (n < 0) return (-1);
158 cp += n;
159 *reinterpret_cast<uint16_t*>(cp) = htons(ns_t_null);
160 cp += INT16SZ;
161 *reinterpret_cast<uint16_t*>(cp) = htons(cl);
162 cp += INT16SZ;
163 *reinterpret_cast<uint32_t*>(cp) = htonl(0);
164 cp += INT32SZ;
165 *reinterpret_cast<uint16_t*>(cp) = htons(0);
166 cp += INT16SZ;
167 hp->arcount = htons(1);
168 break;
169
170 case IQUERY:
171 /*
172 * Initialize answer section
173 */
174 if (ep - cp < 1 + RRFIXEDSZ + datalen) return (-1);
175 *cp++ = '\0'; /* no domain name */
176 *reinterpret_cast<uint16_t*>(cp) = htons(type);
177 cp += INT16SZ;
178 *reinterpret_cast<uint16_t*>(cp) = htons(cl);
179 cp += INT16SZ;
180 *reinterpret_cast<uint32_t*>(cp) = htonl(0);
181 cp += INT32SZ;
182 *reinterpret_cast<uint16_t*>(cp) = htons(datalen);
183 cp += INT16SZ;
184 if (datalen) {
185 memcpy(cp, data, (size_t) datalen);
186 cp += datalen;
187 }
188 hp->ancount = htons(1);
189 break;
190
191 default:
192 return (-1);
193 }
194 return (cp - buf);
195 }
196
res_nopt(res_state statp,int n0,u_char * buf,int buflen,int anslen)197 int res_nopt(res_state statp, int n0, /* current offset in buffer */
198 u_char* buf, /* buffer to put query */
199 int buflen, /* size of buffer */
200 int anslen) /* UDP answer buffer size */
201 {
202 HEADER* hp;
203 u_char *cp, *ep;
204 u_int16_t flags = 0;
205
206 LOG(DEBUG) << __func__;
207
208 hp = (HEADER*) (void*) buf;
209 cp = buf + n0;
210 ep = buf + buflen;
211
212 if ((ep - cp) < 1 + RRFIXEDSZ) return (-1);
213
214 *cp++ = 0; /* "." */
215
216 // Attach OPT pseudo-RR, as documented in RFC2671 (EDNS0).
217 *reinterpret_cast<uint16_t*>(cp) = htons(ns_t_opt); /* TYPE */
218 cp += INT16SZ;
219 if (anslen > 0xffff) anslen = 0xffff;
220 *reinterpret_cast<uint16_t*>(cp) = htons(anslen); /* CLASS = UDP payload size */
221 cp += INT16SZ;
222 *cp++ = NOERROR; /* extended RCODE */
223 *cp++ = 0; /* EDNS version */
224 if (statp->options & RES_USE_DNSSEC) {
225 LOG(DEBUG) << __func__ << ": ENDS0 DNSSEC";
226 flags |= NS_OPT_DNSSEC_OK;
227 }
228 *reinterpret_cast<uint16_t*>(cp) = htons(flags);
229 cp += INT16SZ;
230
231 // EDNS0 padding
232 const uint16_t minlen = static_cast<uint16_t>(cp - buf) + 3 * INT16SZ;
233 const uint16_t extra = minlen % kEdns0Padding;
234 uint16_t padlen = (kEdns0Padding - extra) % kEdns0Padding;
235 if (minlen > buflen) {
236 return -1;
237 }
238 padlen = std::min(padlen, static_cast<uint16_t>(buflen - minlen));
239 *reinterpret_cast<uint16_t*>(cp) = htons(padlen + 2 * INT16SZ); /* RDLEN */
240 cp += INT16SZ;
241 *reinterpret_cast<uint16_t*>(cp) = htons(NS_OPT_PADDING); /* OPTION-CODE */
242 cp += INT16SZ;
243 *reinterpret_cast<uint16_t*>(cp) = htons(padlen); /* OPTION-LENGTH */
244 cp += INT16SZ;
245 memset(cp, 0, padlen);
246 cp += padlen;
247
248 hp->arcount = htons(ntohs(hp->arcount) + 1);
249 return (cp - buf);
250 }
251