1/*	$NetBSD: opt_41.c,v 1.11 2024/02/21 22:52:13 christos Exp $	*/
2
3/*
4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
5 *
6 * SPDX-License-Identifier: MPL-2.0
7 *
8 * This Source Code Form is subject to the terms of the Mozilla Public
9 * License, v. 2.0. If a copy of the MPL was not distributed with this
10 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
11 *
12 * See the COPYRIGHT file distributed with this work for additional
13 * information regarding copyright ownership.
14 */
15
16/* RFC2671 */
17
18#ifndef RDATA_GENERIC_OPT_41_C
19#define RDATA_GENERIC_OPT_41_C
20
21#define RRTYPE_OPT_ATTRIBUTES                                   \
22	(DNS_RDATATYPEATTR_SINGLETON | DNS_RDATATYPEATTR_META | \
23	 DNS_RDATATYPEATTR_NOTQUESTION)
24
25#include <isc/utf8.h>
26
27static isc_result_t
28fromtext_opt(ARGS_FROMTEXT) {
29	/*
30	 * OPT records do not have a text format.
31	 */
32
33	REQUIRE(type == dns_rdatatype_opt);
34
35	UNUSED(type);
36	UNUSED(rdclass);
37	UNUSED(lexer);
38	UNUSED(origin);
39	UNUSED(options);
40	UNUSED(target);
41	UNUSED(callbacks);
42
43	return (ISC_R_NOTIMPLEMENTED);
44}
45
46static isc_result_t
47totext_opt(ARGS_TOTEXT) {
48	isc_region_t r;
49	isc_region_t or ;
50	uint16_t option;
51	uint16_t length;
52	char buf[sizeof("64000 64000")];
53
54	/*
55	 * OPT records do not have a text format.
56	 */
57
58	REQUIRE(rdata->type == dns_rdatatype_opt);
59
60	dns_rdata_toregion(rdata, &r);
61	while (r.length > 0) {
62		option = uint16_fromregion(&r);
63		isc_region_consume(&r, 2);
64		length = uint16_fromregion(&r);
65		isc_region_consume(&r, 2);
66		snprintf(buf, sizeof(buf), "%u %u", option, length);
67		RETERR(str_totext(buf, target));
68		INSIST(r.length >= length);
69		if (length > 0) {
70			if ((tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0) {
71				RETERR(str_totext(" (", target));
72			}
73			RETERR(str_totext(tctx->linebreak, target));
74			or = r;
75			or.length = length;
76			if (tctx->width == 0) { /* No splitting */
77				RETERR(isc_base64_totext(& or, 60, "", target));
78			} else {
79				RETERR(isc_base64_totext(& or, tctx->width - 2,
80							 tctx->linebreak,
81							 target));
82			}
83			isc_region_consume(&r, length);
84			if ((tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0) {
85				RETERR(str_totext(" )", target));
86			}
87		}
88		if (r.length > 0) {
89			RETERR(str_totext(" ", target));
90		}
91	}
92
93	return (ISC_R_SUCCESS);
94}
95
96static isc_result_t
97fromwire_opt(ARGS_FROMWIRE) {
98	isc_region_t sregion;
99	isc_region_t tregion;
100	uint16_t opt;
101	uint16_t length;
102	unsigned int total;
103
104	REQUIRE(type == dns_rdatatype_opt);
105
106	UNUSED(type);
107	UNUSED(rdclass);
108	UNUSED(dctx);
109	UNUSED(options);
110
111	isc_buffer_activeregion(source, &sregion);
112	if (sregion.length == 0) {
113		return (ISC_R_SUCCESS);
114	}
115	total = 0;
116	while (sregion.length != 0) {
117		if (sregion.length < 4) {
118			return (ISC_R_UNEXPECTEDEND);
119		}
120		opt = uint16_fromregion(&sregion);
121		isc_region_consume(&sregion, 2);
122		length = uint16_fromregion(&sregion);
123		isc_region_consume(&sregion, 2);
124		total += 4;
125		if (sregion.length < length) {
126			return (ISC_R_UNEXPECTEDEND);
127		}
128		switch (opt) {
129		case DNS_OPT_LLQ:
130			if (length != 18U) {
131				return (DNS_R_OPTERR);
132			}
133			isc_region_consume(&sregion, length);
134			break;
135		case DNS_OPT_CLIENT_SUBNET: {
136			uint16_t family;
137			uint8_t addrlen;
138			uint8_t scope;
139			uint8_t addrbytes;
140
141			if (length < 4) {
142				return (DNS_R_OPTERR);
143			}
144			family = uint16_fromregion(&sregion);
145			isc_region_consume(&sregion, 2);
146			addrlen = uint8_fromregion(&sregion);
147			isc_region_consume(&sregion, 1);
148			scope = uint8_fromregion(&sregion);
149			isc_region_consume(&sregion, 1);
150
151			switch (family) {
152			case 0:
153				/*
154				 * XXXMUKS: In queries and replies, if
155				 * FAMILY is set to 0, SOURCE
156				 * PREFIX-LENGTH and SCOPE PREFIX-LENGTH
157				 * must be 0 and ADDRESS should not be
158				 * present as the address and prefix
159				 * lengths don't make sense because the
160				 * family is unknown.
161				 */
162				if (addrlen != 0U || scope != 0U) {
163					return (DNS_R_OPTERR);
164				}
165				break;
166			case 1:
167				if (addrlen > 32U || scope > 32U) {
168					return (DNS_R_OPTERR);
169				}
170				break;
171			case 2:
172				if (addrlen > 128U || scope > 128U) {
173					return (DNS_R_OPTERR);
174				}
175				break;
176			default:
177				return (DNS_R_OPTERR);
178			}
179			addrbytes = (addrlen + 7) / 8;
180			if (addrbytes + 4 != length) {
181				return (DNS_R_OPTERR);
182			}
183
184			if (addrbytes != 0U && (addrlen % 8) != 0) {
185				uint8_t bits = ~0U << (8 - (addrlen % 8));
186				bits &= sregion.base[addrbytes - 1];
187				if (bits != sregion.base[addrbytes - 1]) {
188					return (DNS_R_OPTERR);
189				}
190			}
191			isc_region_consume(&sregion, addrbytes);
192			break;
193		}
194		case DNS_OPT_EXPIRE:
195			/*
196			 * Request has zero length.  Response is 32 bits.
197			 */
198			if (length != 0 && length != 4) {
199				return (DNS_R_OPTERR);
200			}
201			isc_region_consume(&sregion, length);
202			break;
203		case DNS_OPT_COOKIE:
204			/*
205			 * Client cookie alone has length 8.
206			 * Client + server cookie is 8 + [8..32].
207			 */
208			if (length != 8 && (length < 16 || length > 40)) {
209				return (DNS_R_OPTERR);
210			}
211			isc_region_consume(&sregion, length);
212			break;
213		case DNS_OPT_KEY_TAG:
214			if (length == 0 || (length % 2) != 0) {
215				return (DNS_R_OPTERR);
216			}
217			isc_region_consume(&sregion, length);
218			break;
219		case DNS_OPT_EDE:
220			if (length < 2) {
221				return (DNS_R_OPTERR);
222			}
223			/* UTF-8 Byte Order Mark is not permitted. RFC 5198 */
224			if (isc_utf8_bom(sregion.base + 2, length - 2)) {
225				return (DNS_R_OPTERR);
226			}
227			/*
228			 * The EXTRA-TEXT field is specified as UTF-8, and
229			 * therefore must be validated for correctness
230			 * according to RFC 3269 security considerations.
231			 */
232			if (!isc_utf8_valid(sregion.base + 2, length - 2)) {
233				return (DNS_R_OPTERR);
234			}
235			isc_region_consume(&sregion, length);
236			break;
237		case DNS_OPT_CLIENT_TAG:
238			FALLTHROUGH;
239		case DNS_OPT_SERVER_TAG:
240			if (length != 2) {
241				return (DNS_R_OPTERR);
242			}
243			isc_region_consume(&sregion, length);
244			break;
245		default:
246			isc_region_consume(&sregion, length);
247			break;
248		}
249		total += length;
250	}
251
252	isc_buffer_activeregion(source, &sregion);
253	isc_buffer_availableregion(target, &tregion);
254	if (tregion.length < total) {
255		return (ISC_R_NOSPACE);
256	}
257	memmove(tregion.base, sregion.base, total);
258	isc_buffer_forward(source, total);
259	isc_buffer_add(target, total);
260
261	return (ISC_R_SUCCESS);
262}
263
264static isc_result_t
265towire_opt(ARGS_TOWIRE) {
266	REQUIRE(rdata->type == dns_rdatatype_opt);
267
268	UNUSED(cctx);
269
270	return (mem_tobuffer(target, rdata->data, rdata->length));
271}
272
273static int
274compare_opt(ARGS_COMPARE) {
275	isc_region_t r1;
276	isc_region_t r2;
277
278	REQUIRE(rdata1->type == rdata2->type);
279	REQUIRE(rdata1->rdclass == rdata2->rdclass);
280	REQUIRE(rdata1->type == dns_rdatatype_opt);
281
282	dns_rdata_toregion(rdata1, &r1);
283	dns_rdata_toregion(rdata2, &r2);
284	return (isc_region_compare(&r1, &r2));
285}
286
287static isc_result_t
288fromstruct_opt(ARGS_FROMSTRUCT) {
289	dns_rdata_opt_t *opt = source;
290	isc_region_t region;
291	uint16_t length;
292
293	REQUIRE(type == dns_rdatatype_opt);
294	REQUIRE(opt != NULL);
295	REQUIRE(opt->common.rdtype == type);
296	REQUIRE(opt->common.rdclass == rdclass);
297	REQUIRE(opt->options != NULL || opt->length == 0);
298
299	UNUSED(type);
300	UNUSED(rdclass);
301
302	region.base = opt->options;
303	region.length = opt->length;
304	while (region.length >= 4) {
305		isc_region_consume(&region, 2); /* opt */
306		length = uint16_fromregion(&region);
307		isc_region_consume(&region, 2);
308		if (region.length < length) {
309			return (ISC_R_UNEXPECTEDEND);
310		}
311		isc_region_consume(&region, length);
312	}
313	if (region.length != 0) {
314		return (ISC_R_UNEXPECTEDEND);
315	}
316
317	return (mem_tobuffer(target, opt->options, opt->length));
318}
319
320static isc_result_t
321tostruct_opt(ARGS_TOSTRUCT) {
322	dns_rdata_opt_t *opt = target;
323	isc_region_t r;
324
325	REQUIRE(rdata->type == dns_rdatatype_opt);
326	REQUIRE(opt != NULL);
327
328	opt->common.rdclass = rdata->rdclass;
329	opt->common.rdtype = rdata->type;
330	ISC_LINK_INIT(&opt->common, link);
331
332	dns_rdata_toregion(rdata, &r);
333	opt->length = r.length;
334	opt->options = mem_maybedup(mctx, r.base, r.length);
335	if (opt->options == NULL) {
336		return (ISC_R_NOMEMORY);
337	}
338
339	opt->offset = 0;
340	opt->mctx = mctx;
341	return (ISC_R_SUCCESS);
342}
343
344static void
345freestruct_opt(ARGS_FREESTRUCT) {
346	dns_rdata_opt_t *opt = source;
347
348	REQUIRE(opt != NULL);
349	REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
350
351	if (opt->mctx == NULL) {
352		return;
353	}
354
355	if (opt->options != NULL) {
356		isc_mem_free(opt->mctx, opt->options);
357	}
358	opt->mctx = NULL;
359}
360
361static isc_result_t
362additionaldata_opt(ARGS_ADDLDATA) {
363	REQUIRE(rdata->type == dns_rdatatype_opt);
364
365	UNUSED(rdata);
366	UNUSED(owner);
367	UNUSED(add);
368	UNUSED(arg);
369
370	return (ISC_R_SUCCESS);
371}
372
373static isc_result_t
374digest_opt(ARGS_DIGEST) {
375	/*
376	 * OPT records are not digested.
377	 */
378
379	REQUIRE(rdata->type == dns_rdatatype_opt);
380
381	UNUSED(rdata);
382	UNUSED(digest);
383	UNUSED(arg);
384
385	return (ISC_R_NOTIMPLEMENTED);
386}
387
388static bool
389checkowner_opt(ARGS_CHECKOWNER) {
390	REQUIRE(type == dns_rdatatype_opt);
391
392	UNUSED(type);
393	UNUSED(rdclass);
394	UNUSED(wildcard);
395
396	return (dns_name_equal(name, dns_rootname));
397}
398
399static bool
400checknames_opt(ARGS_CHECKNAMES) {
401	REQUIRE(rdata->type == dns_rdatatype_opt);
402
403	UNUSED(rdata);
404	UNUSED(owner);
405	UNUSED(bad);
406
407	return (true);
408}
409
410static int
411casecompare_opt(ARGS_COMPARE) {
412	return (compare_opt(rdata1, rdata2));
413}
414
415isc_result_t
416dns_rdata_opt_first(dns_rdata_opt_t *opt) {
417	REQUIRE(opt != NULL);
418	REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
419	REQUIRE(opt->options != NULL || opt->length == 0);
420
421	if (opt->length == 0) {
422		return (ISC_R_NOMORE);
423	}
424
425	opt->offset = 0;
426	return (ISC_R_SUCCESS);
427}
428
429isc_result_t
430dns_rdata_opt_next(dns_rdata_opt_t *opt) {
431	isc_region_t r;
432	uint16_t length;
433
434	REQUIRE(opt != NULL);
435	REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
436	REQUIRE(opt->options != NULL && opt->length != 0);
437	REQUIRE(opt->offset < opt->length);
438
439	INSIST(opt->offset + 4 <= opt->length);
440	r.base = opt->options + opt->offset + 2;
441	r.length = opt->length - opt->offset - 2;
442	length = uint16_fromregion(&r);
443	INSIST(opt->offset + 4 + length <= opt->length);
444	opt->offset = opt->offset + 4 + length;
445	if (opt->offset == opt->length) {
446		return (ISC_R_NOMORE);
447	}
448	return (ISC_R_SUCCESS);
449}
450
451isc_result_t
452dns_rdata_opt_current(dns_rdata_opt_t *opt, dns_rdata_opt_opcode_t *opcode) {
453	isc_region_t r;
454
455	REQUIRE(opt != NULL);
456	REQUIRE(opcode != NULL);
457	REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
458	REQUIRE(opt->options != NULL);
459	REQUIRE(opt->offset < opt->length);
460
461	INSIST(opt->offset + 4 <= opt->length);
462	r.base = opt->options + opt->offset;
463	r.length = opt->length - opt->offset;
464
465	opcode->opcode = uint16_fromregion(&r);
466	isc_region_consume(&r, 2);
467	opcode->length = uint16_fromregion(&r);
468	isc_region_consume(&r, 2);
469	opcode->data = r.base;
470	INSIST(opt->offset + 4 + opcode->length <= opt->length);
471
472	return (ISC_R_SUCCESS);
473}
474
475#endif /* RDATA_GENERIC_OPT_41_C */
476