xref: /freebsd/lib/libc/nameser/ns_print.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*
2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3  * Copyright (c) 1996-1999 by Internet Software Consortium.
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #ifndef lint
19 static const char rcsid[] = "$Id: ns_print.c,v 1.6.18.4 2005/04/27 05:01:09 sra Exp $";
20 #endif
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
23 
24 /* Import. */
25 
26 #include "port_before.h"
27 
28 #include <sys/types.h>
29 #include <sys/socket.h>
30 
31 #include <netinet/in.h>
32 #include <arpa/nameser.h>
33 #include <arpa/inet.h>
34 
35 #ifdef _LIBC
36 #include <assert.h>
37 #define INSIST(cond)	assert(cond)
38 #else
39 #include <isc/assertions.h>
40 #include <isc/dst.h>
41 #endif
42 #include <errno.h>
43 #include <resolv.h>
44 #include <string.h>
45 #include <ctype.h>
46 
47 #include "port_after.h"
48 
49 #ifdef SPRINTF_CHAR
50 # define SPRINTF(x) strlen(sprintf/**/x)
51 #else
52 # define SPRINTF(x) ((size_t)sprintf x)
53 #endif
54 
55 /* Forward. */
56 
57 static size_t	prune_origin(const char *name, const char *origin);
58 static int	charstr(const u_char *rdata, const u_char *edata,
59 			char **buf, size_t *buflen);
60 static int	addname(const u_char *msg, size_t msglen,
61 			const u_char **p, const char *origin,
62 			char **buf, size_t *buflen);
63 static void	addlen(size_t len, char **buf, size_t *buflen);
64 static int	addstr(const char *src, size_t len,
65 		       char **buf, size_t *buflen);
66 static int	addtab(size_t len, size_t target, int spaced,
67 		       char **buf, size_t *buflen);
68 
69 /* Macros. */
70 
71 #define	T(x) \
72 	do { \
73 		if ((x) < 0) \
74 			return (-1); \
75 	} while (0)
76 
77 /* Public. */
78 
79 /*%
80  *	Convert an RR to presentation format.
81  *
82  * return:
83  *\li	Number of characters written to buf, or -1 (check errno).
84  */
85 int
86 ns_sprintrr(const ns_msg *handle, const ns_rr *rr,
87 	    const char *name_ctx, const char *origin,
88 	    char *buf, size_t buflen)
89 {
90 	int n;
91 
92 	n = ns_sprintrrf(ns_msg_base(*handle), ns_msg_size(*handle),
93 			 ns_rr_name(*rr), ns_rr_class(*rr), ns_rr_type(*rr),
94 			 ns_rr_ttl(*rr), ns_rr_rdata(*rr), ns_rr_rdlen(*rr),
95 			 name_ctx, origin, buf, buflen);
96 	return (n);
97 }
98 
99 /*%
100  *	Convert the fields of an RR into presentation format.
101  *
102  * return:
103  *\li	Number of characters written to buf, or -1 (check errno).
104  */
105 int
106 ns_sprintrrf(const u_char *msg, size_t msglen,
107 	    const char *name, ns_class class, ns_type type,
108 	    u_long ttl, const u_char *rdata, size_t rdlen,
109 	    const char *name_ctx, const char *origin,
110 	    char *buf, size_t buflen)
111 {
112 	const char *obuf = buf;
113 	const u_char *edata = rdata + rdlen;
114 	int spaced = 0;
115 
116 	const char *comment;
117 	char tmp[100];
118 	int len, x;
119 
120 	/*
121 	 * Owner.
122 	 */
123 	if (name_ctx != NULL && ns_samename(name_ctx, name) == 1) {
124 		T(addstr("\t\t\t", 3, &buf, &buflen));
125 	} else {
126 		len = prune_origin(name, origin);
127 		if (*name == '\0') {
128 			goto root;
129 		} else if (len == 0) {
130 			T(addstr("@\t\t\t", 4, &buf, &buflen));
131 		} else {
132 			T(addstr(name, len, &buf, &buflen));
133 			/* Origin not used or not root, and no trailing dot? */
134 			if (((origin == NULL || origin[0] == '\0') ||
135 			    (origin[0] != '.' && origin[1] != '\0' &&
136 			    name[len] == '\0')) && name[len - 1] != '.') {
137  root:
138 				T(addstr(".", 1, &buf, &buflen));
139 				len++;
140 			}
141 			T(spaced = addtab(len, 24, spaced, &buf, &buflen));
142 		}
143 	}
144 
145 	/*
146 	 * TTL, Class, Type.
147 	 */
148 	T(x = ns_format_ttl(ttl, buf, buflen));
149 	addlen(x, &buf, &buflen);
150 	len = SPRINTF((tmp, " %s %s", p_class(class), p_type(type)));
151 	T(addstr(tmp, len, &buf, &buflen));
152 	T(spaced = addtab(x + len, 16, spaced, &buf, &buflen));
153 
154 	/*
155 	 * RData.
156 	 */
157 	switch (type) {
158 	case ns_t_a:
159 		if (rdlen != (size_t)NS_INADDRSZ)
160 			goto formerr;
161 		(void) inet_ntop(AF_INET, rdata, buf, buflen);
162 		addlen(strlen(buf), &buf, &buflen);
163 		break;
164 
165 	case ns_t_cname:
166 	case ns_t_mb:
167 	case ns_t_mg:
168 	case ns_t_mr:
169 	case ns_t_ns:
170 	case ns_t_ptr:
171 	case ns_t_dname:
172 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
173 		break;
174 
175 	case ns_t_hinfo:
176 	case ns_t_isdn:
177 		/* First word. */
178 		T(len = charstr(rdata, edata, &buf, &buflen));
179 		if (len == 0)
180 			goto formerr;
181 		rdata += len;
182 		T(addstr(" ", 1, &buf, &buflen));
183 
184 
185 		/* Second word, optional in ISDN records. */
186 		if (type == ns_t_isdn && rdata == edata)
187 			break;
188 
189 		T(len = charstr(rdata, edata, &buf, &buflen));
190 		if (len == 0)
191 			goto formerr;
192 		rdata += len;
193 		break;
194 
195 	case ns_t_soa: {
196 		u_long t;
197 
198 		/* Server name. */
199 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
200 		T(addstr(" ", 1, &buf, &buflen));
201 
202 		/* Administrator name. */
203 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
204 		T(addstr(" (\n", 3, &buf, &buflen));
205 		spaced = 0;
206 
207 		if ((edata - rdata) != 5*NS_INT32SZ)
208 			goto formerr;
209 
210 		/* Serial number. */
211 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
212 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
213 		len = SPRINTF((tmp, "%lu", t));
214 		T(addstr(tmp, len, &buf, &buflen));
215 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
216 		T(addstr("; serial\n", 9, &buf, &buflen));
217 		spaced = 0;
218 
219 		/* Refresh interval. */
220 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
221 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
222 		T(len = ns_format_ttl(t, buf, buflen));
223 		addlen(len, &buf, &buflen);
224 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
225 		T(addstr("; refresh\n", 10, &buf, &buflen));
226 		spaced = 0;
227 
228 		/* Retry interval. */
229 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
230 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
231 		T(len = ns_format_ttl(t, buf, buflen));
232 		addlen(len, &buf, &buflen);
233 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
234 		T(addstr("; retry\n", 8, &buf, &buflen));
235 		spaced = 0;
236 
237 		/* Expiry. */
238 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
239 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
240 		T(len = ns_format_ttl(t, buf, buflen));
241 		addlen(len, &buf, &buflen);
242 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
243 		T(addstr("; expiry\n", 9, &buf, &buflen));
244 		spaced = 0;
245 
246 		/* Minimum TTL. */
247 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
248 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
249 		T(len = ns_format_ttl(t, buf, buflen));
250 		addlen(len, &buf, &buflen);
251 		T(addstr(" )", 2, &buf, &buflen));
252 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
253 		T(addstr("; minimum\n", 10, &buf, &buflen));
254 
255 		break;
256 	    }
257 
258 	case ns_t_mx:
259 	case ns_t_afsdb:
260 	case ns_t_rt: {
261 		u_int t;
262 
263 		if (rdlen < (size_t)NS_INT16SZ)
264 			goto formerr;
265 
266 		/* Priority. */
267 		t = ns_get16(rdata);
268 		rdata += NS_INT16SZ;
269 		len = SPRINTF((tmp, "%u ", t));
270 		T(addstr(tmp, len, &buf, &buflen));
271 
272 		/* Target. */
273 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
274 
275 		break;
276 	    }
277 
278 	case ns_t_px: {
279 		u_int t;
280 
281 		if (rdlen < (size_t)NS_INT16SZ)
282 			goto formerr;
283 
284 		/* Priority. */
285 		t = ns_get16(rdata);
286 		rdata += NS_INT16SZ;
287 		len = SPRINTF((tmp, "%u ", t));
288 		T(addstr(tmp, len, &buf, &buflen));
289 
290 		/* Name1. */
291 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
292 		T(addstr(" ", 1, &buf, &buflen));
293 
294 		/* Name2. */
295 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
296 
297 		break;
298 	    }
299 
300 	case ns_t_x25:
301 		T(len = charstr(rdata, edata, &buf, &buflen));
302 		if (len == 0)
303 			goto formerr;
304 		rdata += len;
305 		break;
306 
307 	case ns_t_txt:
308 		while (rdata < edata) {
309 			T(len = charstr(rdata, edata, &buf, &buflen));
310 			if (len == 0)
311 				goto formerr;
312 			rdata += len;
313 			if (rdata < edata)
314 				T(addstr(" ", 1, &buf, &buflen));
315 		}
316 		break;
317 
318 	case ns_t_nsap: {
319 		char t[2+255*3];
320 
321 		(void) inet_nsap_ntoa(rdlen, rdata, t);
322 		T(addstr(t, strlen(t), &buf, &buflen));
323 		break;
324 	    }
325 
326 	case ns_t_aaaa:
327 		if (rdlen != (size_t)NS_IN6ADDRSZ)
328 			goto formerr;
329 		(void) inet_ntop(AF_INET6, rdata, buf, buflen);
330 		addlen(strlen(buf), &buf, &buflen);
331 		break;
332 
333 	case ns_t_loc: {
334 		char t[255];
335 
336 		/* XXX protocol format checking? */
337 		(void) loc_ntoa(rdata, t);
338 		T(addstr(t, strlen(t), &buf, &buflen));
339 		break;
340 	    }
341 
342 	case ns_t_naptr: {
343 		u_int order, preference;
344 		char t[50];
345 
346 		if (rdlen < 2U*NS_INT16SZ)
347 			goto formerr;
348 
349 		/* Order, Precedence. */
350 		order = ns_get16(rdata);	rdata += NS_INT16SZ;
351 		preference = ns_get16(rdata);	rdata += NS_INT16SZ;
352 		len = SPRINTF((t, "%u %u ", order, preference));
353 		T(addstr(t, len, &buf, &buflen));
354 
355 		/* Flags. */
356 		T(len = charstr(rdata, edata, &buf, &buflen));
357 		if (len == 0)
358 			goto formerr;
359 		rdata += len;
360 		T(addstr(" ", 1, &buf, &buflen));
361 
362 		/* Service. */
363 		T(len = charstr(rdata, edata, &buf, &buflen));
364 		if (len == 0)
365 			goto formerr;
366 		rdata += len;
367 		T(addstr(" ", 1, &buf, &buflen));
368 
369 		/* Regexp. */
370 		T(len = charstr(rdata, edata, &buf, &buflen));
371 		if (len < 0)
372 			return (-1);
373 		if (len == 0)
374 			goto formerr;
375 		rdata += len;
376 		T(addstr(" ", 1, &buf, &buflen));
377 
378 		/* Server. */
379 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
380 		break;
381 	    }
382 
383 	case ns_t_srv: {
384 		u_int priority, weight, port;
385 		char t[50];
386 
387 		if (rdlen < 3U*NS_INT16SZ)
388 			goto formerr;
389 
390 		/* Priority, Weight, Port. */
391 		priority = ns_get16(rdata);  rdata += NS_INT16SZ;
392 		weight   = ns_get16(rdata);  rdata += NS_INT16SZ;
393 		port     = ns_get16(rdata);  rdata += NS_INT16SZ;
394 		len = SPRINTF((t, "%u %u %u ", priority, weight, port));
395 		T(addstr(t, len, &buf, &buflen));
396 
397 		/* Server. */
398 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
399 		break;
400 	    }
401 
402 	case ns_t_minfo:
403 	case ns_t_rp:
404 		/* Name1. */
405 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
406 		T(addstr(" ", 1, &buf, &buflen));
407 
408 		/* Name2. */
409 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
410 
411 		break;
412 
413 	case ns_t_wks: {
414 		int n, lcnt;
415 
416 		if (rdlen < 1U + NS_INT32SZ)
417 			goto formerr;
418 
419 		/* Address. */
420 		(void) inet_ntop(AF_INET, rdata, buf, buflen);
421 		addlen(strlen(buf), &buf, &buflen);
422 		rdata += NS_INADDRSZ;
423 
424 		/* Protocol. */
425 		len = SPRINTF((tmp, " %u ( ", *rdata));
426 		T(addstr(tmp, len, &buf, &buflen));
427 		rdata += NS_INT8SZ;
428 
429 		/* Bit map. */
430 		n = 0;
431 		lcnt = 0;
432 		while (rdata < edata) {
433 			u_int c = *rdata++;
434 			do {
435 				if (c & 0200) {
436 					if (lcnt == 0) {
437 						T(addstr("\n\t\t\t\t", 5,
438 							 &buf, &buflen));
439 						lcnt = 10;
440 						spaced = 0;
441 					}
442 					len = SPRINTF((tmp, "%d ", n));
443 					T(addstr(tmp, len, &buf, &buflen));
444 					lcnt--;
445 				}
446 				c <<= 1;
447 			} while (++n & 07);
448 		}
449 		T(addstr(")", 1, &buf, &buflen));
450 
451 		break;
452 	    }
453 
454 	case ns_t_key: {
455 		char base64_key[NS_MD5RSA_MAX_BASE64];
456 		u_int keyflags, protocol, algorithm, key_id;
457 		const char *leader;
458 		int n;
459 
460 		if (rdlen < 0U + NS_INT16SZ + NS_INT8SZ + NS_INT8SZ)
461 			goto formerr;
462 
463 		/* Key flags, Protocol, Algorithm. */
464 #ifndef _LIBC
465 		key_id = dst_s_dns_key_id(rdata, edata-rdata);
466 #else
467 		key_id = 0;
468 #endif
469 		keyflags = ns_get16(rdata);  rdata += NS_INT16SZ;
470 		protocol = *rdata++;
471 		algorithm = *rdata++;
472 		len = SPRINTF((tmp, "0x%04x %u %u",
473 			       keyflags, protocol, algorithm));
474 		T(addstr(tmp, len, &buf, &buflen));
475 
476 		/* Public key data. */
477 		len = b64_ntop(rdata, edata - rdata,
478 			       base64_key, sizeof base64_key);
479 		if (len < 0)
480 			goto formerr;
481 		if (len > 15) {
482 			T(addstr(" (", 2, &buf, &buflen));
483 			leader = "\n\t\t";
484 			spaced = 0;
485 		} else
486 			leader = " ";
487 		for (n = 0; n < len; n += 48) {
488 			T(addstr(leader, strlen(leader), &buf, &buflen));
489 			T(addstr(base64_key + n, MIN(len - n, 48),
490 				 &buf, &buflen));
491 		}
492 		if (len > 15)
493 			T(addstr(" )", 2, &buf, &buflen));
494 		n = SPRINTF((tmp, " ; key_tag= %u", key_id));
495 		T(addstr(tmp, n, &buf, &buflen));
496 
497 		break;
498 	    }
499 
500 	case ns_t_sig: {
501 		char base64_key[NS_MD5RSA_MAX_BASE64];
502 		u_int type, algorithm, labels, footprint;
503 		const char *leader;
504 		u_long t;
505 		int n;
506 
507 		if (rdlen < 22U)
508 			goto formerr;
509 
510 		/* Type covered, Algorithm, Label count, Original TTL. */
511 	        type = ns_get16(rdata);  rdata += NS_INT16SZ;
512 		algorithm = *rdata++;
513 		labels = *rdata++;
514 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
515 		len = SPRINTF((tmp, "%s %d %d %lu ",
516 			       p_type(type), algorithm, labels, t));
517 		T(addstr(tmp, len, &buf, &buflen));
518 		if (labels > (u_int)dn_count_labels(name))
519 			goto formerr;
520 
521 		/* Signature expiry. */
522 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
523 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
524 		T(addstr(tmp, len, &buf, &buflen));
525 
526 		/* Time signed. */
527 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
528 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
529 		T(addstr(tmp, len, &buf, &buflen));
530 
531 		/* Signature Footprint. */
532 		footprint = ns_get16(rdata);  rdata += NS_INT16SZ;
533 		len = SPRINTF((tmp, "%u ", footprint));
534 		T(addstr(tmp, len, &buf, &buflen));
535 
536 		/* Signer's name. */
537 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
538 
539 		/* Signature. */
540 		len = b64_ntop(rdata, edata - rdata,
541 			       base64_key, sizeof base64_key);
542 		if (len > 15) {
543 			T(addstr(" (", 2, &buf, &buflen));
544 			leader = "\n\t\t";
545 			spaced = 0;
546 		} else
547 			leader = " ";
548 		if (len < 0)
549 			goto formerr;
550 		for (n = 0; n < len; n += 48) {
551 			T(addstr(leader, strlen(leader), &buf, &buflen));
552 			T(addstr(base64_key + n, MIN(len - n, 48),
553 				 &buf, &buflen));
554 		}
555 		if (len > 15)
556 			T(addstr(" )", 2, &buf, &buflen));
557 		break;
558 	    }
559 
560 	case ns_t_nxt: {
561 		int n, c;
562 
563 		/* Next domain name. */
564 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
565 
566 		/* Type bit map. */
567 		n = edata - rdata;
568 		for (c = 0; c < n*8; c++)
569 			if (NS_NXT_BIT_ISSET(c, rdata)) {
570 				len = SPRINTF((tmp, " %s", p_type(c)));
571 				T(addstr(tmp, len, &buf, &buflen));
572 			}
573 		break;
574 	    }
575 
576 	case ns_t_cert: {
577 		u_int c_type, key_tag, alg;
578 		int n;
579 		unsigned int siz;
580 		char base64_cert[8192], tmp[40];
581 		const char *leader;
582 
583 		c_type  = ns_get16(rdata); rdata += NS_INT16SZ;
584 		key_tag = ns_get16(rdata); rdata += NS_INT16SZ;
585 		alg = (u_int) *rdata++;
586 
587 		len = SPRINTF((tmp, "%d %d %d ", c_type, key_tag, alg));
588 		T(addstr(tmp, len, &buf, &buflen));
589 		siz = (edata-rdata)*4/3 + 4; /* "+4" accounts for trailing \0 */
590 		if (siz > sizeof(base64_cert) * 3/4) {
591 			const char *str = "record too long to print";
592 			T(addstr(str, strlen(str), &buf, &buflen));
593 		}
594 		else {
595 			len = b64_ntop(rdata, edata-rdata, base64_cert, siz);
596 
597 			if (len < 0)
598 				goto formerr;
599 			else if (len > 15) {
600 				T(addstr(" (", 2, &buf, &buflen));
601 				leader = "\n\t\t";
602 				spaced = 0;
603 			}
604 			else
605 				leader = " ";
606 
607 			for (n = 0; n < len; n += 48) {
608 				T(addstr(leader, strlen(leader),
609 					 &buf, &buflen));
610 				T(addstr(base64_cert + n, MIN(len - n, 48),
611 					 &buf, &buflen));
612 			}
613 			if (len > 15)
614 				T(addstr(" )", 2, &buf, &buflen));
615 		}
616 		break;
617 	    }
618 
619 	case ns_t_tkey: {
620 		/* KJD - need to complete this */
621 		u_long t;
622 		int mode, err, keysize;
623 
624 		/* Algorithm name. */
625 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
626 		T(addstr(" ", 1, &buf, &buflen));
627 
628 		/* Inception. */
629 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
630 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
631 		T(addstr(tmp, len, &buf, &buflen));
632 
633 		/* Experation. */
634 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
635 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
636 		T(addstr(tmp, len, &buf, &buflen));
637 
638 		/* Mode , Error, Key Size. */
639 		/* Priority, Weight, Port. */
640 		mode = ns_get16(rdata);  rdata += NS_INT16SZ;
641 		err  = ns_get16(rdata);  rdata += NS_INT16SZ;
642 		keysize  = ns_get16(rdata);  rdata += NS_INT16SZ;
643 		len = SPRINTF((tmp, "%u %u %u ", mode, err, keysize));
644 		T(addstr(tmp, len, &buf, &buflen));
645 
646 		/* XXX need to dump key, print otherdata length & other data */
647 		break;
648 	    }
649 
650 	case ns_t_tsig: {
651 		/* BEW - need to complete this */
652 		int n;
653 
654 		T(len = addname(msg, msglen, &rdata, origin, &buf, &buflen));
655 		T(addstr(" ", 1, &buf, &buflen));
656 		rdata += 8; /*%< time */
657 		n = ns_get16(rdata); rdata += INT16SZ;
658 		rdata += n; /*%< sig */
659 		n = ns_get16(rdata); rdata += INT16SZ; /*%< original id */
660 		sprintf(buf, "%d", ns_get16(rdata));
661 		rdata += INT16SZ;
662 		addlen(strlen(buf), &buf, &buflen);
663 		break;
664 	    }
665 
666 	case ns_t_a6: {
667 		struct in6_addr a;
668 		int pbyte, pbit;
669 
670 		/* prefix length */
671 		if (rdlen == 0U) goto formerr;
672 		len = SPRINTF((tmp, "%d ", *rdata));
673 		T(addstr(tmp, len, &buf, &buflen));
674 		pbit = *rdata;
675 		if (pbit > 128) goto formerr;
676 		pbyte = (pbit & ~7) / 8;
677 		rdata++;
678 
679 		/* address suffix: provided only when prefix len != 128 */
680 		if (pbit < 128) {
681 			if (rdata + pbyte >= edata) goto formerr;
682 			memset(&a, 0, sizeof(a));
683 			memcpy(&a.s6_addr[pbyte], rdata, sizeof(a) - pbyte);
684 			(void) inet_ntop(AF_INET6, &a, buf, buflen);
685 			addlen(strlen(buf), &buf, &buflen);
686 			rdata += sizeof(a) - pbyte;
687 		}
688 
689 		/* prefix name: provided only when prefix len > 0 */
690 		if (pbit == 0)
691 			break;
692 		if (rdata >= edata) goto formerr;
693 		T(addstr(" ", 1, &buf, &buflen));
694 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
695 
696 		break;
697 	    }
698 
699 	case ns_t_opt: {
700 		len = SPRINTF((tmp, "%u bytes", class));
701 		T(addstr(tmp, len, &buf, &buflen));
702 		break;
703 	    }
704 
705 	default:
706 		comment = "unknown RR type";
707 		goto hexify;
708 	}
709 	return (buf - obuf);
710  formerr:
711 	comment = "RR format error";
712  hexify: {
713 	int n, m;
714 	char *p;
715 
716 	len = SPRINTF((tmp, "\\# %u%s\t; %s", (unsigned)(edata - rdata),
717 		       rdlen != 0U ? " (" : "", comment));
718 	T(addstr(tmp, len, &buf, &buflen));
719 	while (rdata < edata) {
720 		p = tmp;
721 		p += SPRINTF((p, "\n\t"));
722 		spaced = 0;
723 		n = MIN(16, edata - rdata);
724 		for (m = 0; m < n; m++)
725 			p += SPRINTF((p, "%02x ", rdata[m]));
726 		T(addstr(tmp, p - tmp, &buf, &buflen));
727 		if (n < 16) {
728 			T(addstr(")", 1, &buf, &buflen));
729 			T(addtab(p - tmp + 1, 48, spaced, &buf, &buflen));
730 		}
731 		p = tmp;
732 		p += SPRINTF((p, "; "));
733 		for (m = 0; m < n; m++)
734 			*p++ = (isascii(rdata[m]) && isprint(rdata[m]))
735 				? rdata[m]
736 				: '.';
737 		T(addstr(tmp, p - tmp, &buf, &buflen));
738 		rdata += n;
739 	}
740 	return (buf - obuf);
741     }
742 }
743 
744 /* Private. */
745 
746 /*%
747  * size_t
748  * prune_origin(name, origin)
749  *	Find out if the name is at or under the current origin.
750  * return:
751  *	Number of characters in name before start of origin,
752  *	or length of name if origin does not match.
753  * notes:
754  *	This function should share code with samedomain().
755  */
756 static size_t
757 prune_origin(const char *name, const char *origin) {
758 	const char *oname = name;
759 
760 	while (*name != '\0') {
761 		if (origin != NULL && ns_samename(name, origin) == 1)
762 			return (name - oname - (name > oname));
763 		while (*name != '\0') {
764 			if (*name == '\\') {
765 				name++;
766 				/* XXX need to handle \nnn form. */
767 				if (*name == '\0')
768 					break;
769 			} else if (*name == '.') {
770 				name++;
771 				break;
772 			}
773 			name++;
774 		}
775 	}
776 	return (name - oname);
777 }
778 
779 /*%
780  * int
781  * charstr(rdata, edata, buf, buflen)
782  *	Format a <character-string> into the presentation buffer.
783  * return:
784  *	Number of rdata octets consumed
785  *	0 for protocol format error
786  *	-1 for output buffer error
787  * side effects:
788  *	buffer is advanced on success.
789  */
790 static int
791 charstr(const u_char *rdata, const u_char *edata, char **buf, size_t *buflen) {
792 	const u_char *odata = rdata;
793 	size_t save_buflen = *buflen;
794 	char *save_buf = *buf;
795 
796 	if (addstr("\"", 1, buf, buflen) < 0)
797 		goto enospc;
798 	if (rdata < edata) {
799 		int n = *rdata;
800 
801 		if (rdata + 1 + n <= edata) {
802 			rdata++;
803 			while (n-- > 0) {
804 				if (strchr("\n\"\\", *rdata) != NULL)
805 					if (addstr("\\", 1, buf, buflen) < 0)
806 						goto enospc;
807 				if (addstr((const char *)rdata, 1,
808 					   buf, buflen) < 0)
809 					goto enospc;
810 				rdata++;
811 			}
812 		}
813 	}
814 	if (addstr("\"", 1, buf, buflen) < 0)
815 		goto enospc;
816 	return (rdata - odata);
817  enospc:
818 	errno = ENOSPC;
819 	*buf = save_buf;
820 	*buflen = save_buflen;
821 	return (-1);
822 }
823 
824 static int
825 addname(const u_char *msg, size_t msglen,
826 	const u_char **pp, const char *origin,
827 	char **buf, size_t *buflen)
828 {
829 	size_t newlen, save_buflen = *buflen;
830 	char *save_buf = *buf;
831 	int n;
832 
833 	n = dn_expand(msg, msg + msglen, *pp, *buf, *buflen);
834 	if (n < 0)
835 		goto enospc;	/*%< Guess. */
836 	newlen = prune_origin(*buf, origin);
837 	if (**buf == '\0') {
838 		goto root;
839 	} else if (newlen == 0U) {
840 		/* Use "@" instead of name. */
841 		if (newlen + 2 > *buflen)
842 			goto enospc;        /* No room for "@\0". */
843 		(*buf)[newlen++] = '@';
844 		(*buf)[newlen] = '\0';
845 	} else {
846 		if (((origin == NULL || origin[0] == '\0') ||
847 		    (origin[0] != '.' && origin[1] != '\0' &&
848 		    (*buf)[newlen] == '\0')) && (*buf)[newlen - 1] != '.') {
849 			/* No trailing dot. */
850  root:
851 			if (newlen + 2 > *buflen)
852 				goto enospc;	/* No room for ".\0". */
853 			(*buf)[newlen++] = '.';
854 			(*buf)[newlen] = '\0';
855 		}
856 	}
857 	*pp += n;
858 	addlen(newlen, buf, buflen);
859 	**buf = '\0';
860 	return (newlen);
861  enospc:
862 	errno = ENOSPC;
863 	*buf = save_buf;
864 	*buflen = save_buflen;
865 	return (-1);
866 }
867 
868 static void
869 addlen(size_t len, char **buf, size_t *buflen) {
870 	INSIST(len <= *buflen);
871 	*buf += len;
872 	*buflen -= len;
873 }
874 
875 static int
876 addstr(const char *src, size_t len, char **buf, size_t *buflen) {
877 	if (len >= *buflen) {
878 		errno = ENOSPC;
879 		return (-1);
880 	}
881 	memcpy(*buf, src, len);
882 	addlen(len, buf, buflen);
883 	**buf = '\0';
884 	return (0);
885 }
886 
887 static int
888 addtab(size_t len, size_t target, int spaced, char **buf, size_t *buflen) {
889 	size_t save_buflen = *buflen;
890 	char *save_buf = *buf;
891 	int t;
892 
893 	if (spaced || len >= target - 1) {
894 		T(addstr("  ", 2, buf, buflen));
895 		spaced = 1;
896 	} else {
897 		for (t = (target - len - 1) / 8; t >= 0; t--)
898 			if (addstr("\t", 1, buf, buflen) < 0) {
899 				*buflen = save_buflen;
900 				*buf = save_buf;
901 				return (-1);
902 			}
903 		spaced = 0;
904 	}
905 	return (spaced);
906 }
907 
908 /*! \file */
909