xref: /dragonfly/lib/libc/nameser/ns_print.c (revision 926deccb)
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 1.10 2005/04/27 04:56:40 sra Exp $";
20 #endif
21 
22 /* Import. */
23 
24 #include "port_before.h"
25 
26 #include <sys/types.h>
27 #include <sys/socket.h>
28 
29 #include <netinet/in.h>
30 #include <arpa/nameser.h>
31 #include <arpa/inet.h>
32 
33 #ifdef _LIBC
34 #include <assert.h>
35 #define INSIST(cond)   assert(cond)
36 #else
37 #include <isc/assertions.h>
38 #include <isc/dst.h>
39 #endif
40 #include <errno.h>
41 #include <resolv.h>
42 #include <string.h>
43 #include <ctype.h>
44 
45 #include "port_after.h"
46 
47 #ifdef SPRINTF_CHAR
48 # define SPRINTF(x) strlen(sprintf/**/x)
49 #else
50 # define SPRINTF(x) ((size_t)sprintf x)
51 #endif
52 
53 /* Forward. */
54 
55 static size_t	prune_origin(const char *name, const char *origin);
56 static int	charstr(const u_char *rdata, const u_char *edata,
57 			char **buf, size_t *buflen);
58 static int	addname(const u_char *msg, size_t msglen,
59 			const u_char **p, const char *origin,
60 			char **buf, size_t *buflen);
61 static void	addlen(size_t len, char **buf, size_t *buflen);
62 static int	addstr(const char *src, size_t len,
63 		       char **buf, size_t *buflen);
64 static int	addtab(size_t len, size_t target, int spaced,
65 		       char **buf, size_t *buflen);
66 
67 /* Macros. */
68 
69 #define	T(x) \
70 	do { \
71 		if ((x) < 0) \
72 			return (-1); \
73 	} while (0)
74 
75 /* Public. */
76 
77 /*%
78  *	Convert an RR to presentation format.
79  *
80  * return:
81  *\li	Number of characters written to buf, or -1 (check errno).
82  */
83 int
84 ns_sprintrr(const ns_msg *handle, const ns_rr *rr,
85 	    const char *name_ctx, const char *origin,
86 	    char *buf, size_t buflen)
87 {
88 	int n;
89 
90 	n = ns_sprintrrf(ns_msg_base(*handle), ns_msg_size(*handle),
91 			 ns_rr_name(*rr), ns_rr_class(*rr), ns_rr_type(*rr),
92 			 ns_rr_ttl(*rr), ns_rr_rdata(*rr), ns_rr_rdlen(*rr),
93 			 name_ctx, origin, buf, buflen);
94 	return (n);
95 }
96 
97 /*%
98  *	Convert the fields of an RR into presentation format.
99  *
100  * return:
101  *\li	Number of characters written to buf, or -1 (check errno).
102  */
103 int
104 ns_sprintrrf(const u_char *msg, size_t msglen,
105 	    const char *name, ns_class class, ns_type type,
106 	    u_long ttl, const u_char *rdata, size_t rdlen,
107 	    const char *name_ctx, const char *origin,
108 	    char *buf, size_t buflen)
109 {
110 	const char *obuf = buf;
111 	const u_char *edata = rdata + rdlen;
112 	int spaced = 0;
113 
114 	const char *comment;
115 	char tmp[100];
116 	int len, x;
117 
118 	/*
119 	 * Owner.
120 	 */
121 	if (name_ctx != NULL && ns_samename(name_ctx, name) == 1) {
122 		T(addstr("\t\t\t", 3, &buf, &buflen));
123 	} else {
124 		len = prune_origin(name, origin);
125 		if (*name == '\0') {
126 			goto root;
127 		} else if (len == 0) {
128 			T(addstr("@\t\t\t", 4, &buf, &buflen));
129 		} else {
130 			T(addstr(name, len, &buf, &buflen));
131 			/* Origin not used or not root, and no trailing dot? */
132 			if (((origin == NULL || origin[0] == '\0') ||
133 			    (origin[0] != '.' && origin[1] != '\0' &&
134 			    name[len] == '\0')) && name[len - 1] != '.') {
135  root:
136 				T(addstr(".", 1, &buf, &buflen));
137 				len++;
138 			}
139 			T(spaced = addtab(len, 24, spaced, &buf, &buflen));
140 		}
141 	}
142 
143 	/*
144 	 * TTL, Class, Type.
145 	 */
146 	T(x = ns_format_ttl(ttl, buf, buflen));
147 	addlen(x, &buf, &buflen);
148 	len = SPRINTF((tmp, " %s %s", p_class(class), p_type(type)));
149 	T(addstr(tmp, len, &buf, &buflen));
150 	T(spaced = addtab(x + len, 16, spaced, &buf, &buflen));
151 
152 	/*
153 	 * RData.
154 	 */
155 	switch (type) {
156 	case ns_t_a:
157 		if (rdlen != (size_t)NS_INADDRSZ)
158 			goto formerr;
159 		(void) inet_ntop(AF_INET, rdata, buf, buflen);
160 		addlen(strlen(buf), &buf, &buflen);
161 		break;
162 
163 	case ns_t_cname:
164 	case ns_t_mb:
165 	case ns_t_mg:
166 	case ns_t_mr:
167 	case ns_t_ns:
168 	case ns_t_ptr:
169 	case ns_t_dname:
170 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
171 		break;
172 
173 	case ns_t_hinfo:
174 	case ns_t_isdn:
175 		/* First word. */
176 		T(len = charstr(rdata, edata, &buf, &buflen));
177 		if (len == 0)
178 			goto formerr;
179 		rdata += len;
180 		T(addstr(" ", 1, &buf, &buflen));
181 
182 
183 		/* Second word, optional in ISDN records. */
184 		if (type == ns_t_isdn && rdata == edata)
185 			break;
186 
187 		T(len = charstr(rdata, edata, &buf, &buflen));
188 		if (len == 0)
189 			goto formerr;
190 		rdata += len;
191 		break;
192 
193 	case ns_t_soa: {
194 		u_long t;
195 
196 		/* Server name. */
197 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
198 		T(addstr(" ", 1, &buf, &buflen));
199 
200 		/* Administrator name. */
201 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
202 		T(addstr(" (\n", 3, &buf, &buflen));
203 		spaced = 0;
204 
205 		if ((edata - rdata) != 5*NS_INT32SZ)
206 			goto formerr;
207 
208 		/* Serial number. */
209 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
210 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
211 		len = SPRINTF((tmp, "%lu", t));
212 		T(addstr(tmp, len, &buf, &buflen));
213 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
214 		T(addstr("; serial\n", 9, &buf, &buflen));
215 		spaced = 0;
216 
217 		/* Refresh interval. */
218 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
219 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
220 		T(len = ns_format_ttl(t, buf, buflen));
221 		addlen(len, &buf, &buflen);
222 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
223 		T(addstr("; refresh\n", 10, &buf, &buflen));
224 		spaced = 0;
225 
226 		/* Retry interval. */
227 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
228 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
229 		T(len = ns_format_ttl(t, buf, buflen));
230 		addlen(len, &buf, &buflen);
231 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
232 		T(addstr("; retry\n", 8, &buf, &buflen));
233 		spaced = 0;
234 
235 		/* Expiry. */
236 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
237 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
238 		T(len = ns_format_ttl(t, buf, buflen));
239 		addlen(len, &buf, &buflen);
240 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
241 		T(addstr("; expiry\n", 9, &buf, &buflen));
242 		spaced = 0;
243 
244 		/* Minimum TTL. */
245 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
246 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
247 		T(len = ns_format_ttl(t, buf, buflen));
248 		addlen(len, &buf, &buflen);
249 		T(addstr(" )", 2, &buf, &buflen));
250 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
251 		T(addstr("; minimum\n", 10, &buf, &buflen));
252 
253 		break;
254 	    }
255 
256 	case ns_t_mx:
257 	case ns_t_afsdb:
258 	case ns_t_rt: {
259 		u_int t;
260 
261 		if (rdlen < (size_t)NS_INT16SZ)
262 			goto formerr;
263 
264 		/* Priority. */
265 		t = ns_get16(rdata);
266 		rdata += NS_INT16SZ;
267 		len = SPRINTF((tmp, "%u ", t));
268 		T(addstr(tmp, len, &buf, &buflen));
269 
270 		/* Target. */
271 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
272 
273 		break;
274 	    }
275 
276 	case ns_t_px: {
277 		u_int t;
278 
279 		if (rdlen < (size_t)NS_INT16SZ)
280 			goto formerr;
281 
282 		/* Priority. */
283 		t = ns_get16(rdata);
284 		rdata += NS_INT16SZ;
285 		len = SPRINTF((tmp, "%u ", t));
286 		T(addstr(tmp, len, &buf, &buflen));
287 
288 		/* Name1. */
289 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
290 		T(addstr(" ", 1, &buf, &buflen));
291 
292 		/* Name2. */
293 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
294 
295 		break;
296 	    }
297 
298 	case ns_t_x25:
299 		T(len = charstr(rdata, edata, &buf, &buflen));
300 		if (len == 0)
301 			goto formerr;
302 		rdata += len;
303 		break;
304 
305 	case ns_t_txt:
306 		while (rdata < edata) {
307 			T(len = charstr(rdata, edata, &buf, &buflen));
308 			if (len == 0)
309 				goto formerr;
310 			rdata += len;
311 			if (rdata < edata)
312 				T(addstr(" ", 1, &buf, &buflen));
313 		}
314 		break;
315 
316 	case ns_t_nsap: {
317 		char t[2+255*3];
318 
319 		(void) inet_nsap_ntoa(rdlen, rdata, t);
320 		T(addstr(t, strlen(t), &buf, &buflen));
321 		break;
322 	    }
323 
324 	case ns_t_aaaa:
325 		if (rdlen != (size_t)NS_IN6ADDRSZ)
326 			goto formerr;
327 		(void) inet_ntop(AF_INET6, rdata, buf, buflen);
328 		addlen(strlen(buf), &buf, &buflen);
329 		break;
330 
331 	case ns_t_loc: {
332 		char t[255];
333 
334 		/* XXX protocol format checking? */
335 		(void) loc_ntoa(rdata, t);
336 		T(addstr(t, strlen(t), &buf, &buflen));
337 		break;
338 	    }
339 
340 	case ns_t_naptr: {
341 		u_int order, preference;
342 		char t[50];
343 
344 		if (rdlen < 2U*NS_INT16SZ)
345 			goto formerr;
346 
347 		/* Order, Precedence. */
348 		order = ns_get16(rdata);	rdata += NS_INT16SZ;
349 		preference = ns_get16(rdata);	rdata += NS_INT16SZ;
350 		len = SPRINTF((t, "%u %u ", order, preference));
351 		T(addstr(t, len, &buf, &buflen));
352 
353 		/* Flags. */
354 		T(len = charstr(rdata, edata, &buf, &buflen));
355 		if (len == 0)
356 			goto formerr;
357 		rdata += len;
358 		T(addstr(" ", 1, &buf, &buflen));
359 
360 		/* Service. */
361 		T(len = charstr(rdata, edata, &buf, &buflen));
362 		if (len == 0)
363 			goto formerr;
364 		rdata += len;
365 		T(addstr(" ", 1, &buf, &buflen));
366 
367 		/* Regexp. */
368 		T(len = charstr(rdata, edata, &buf, &buflen));
369 		if (len < 0)
370 			return (-1);
371 		if (len == 0)
372 			goto formerr;
373 		rdata += len;
374 		T(addstr(" ", 1, &buf, &buflen));
375 
376 		/* Server. */
377 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
378 		break;
379 	    }
380 
381 	case ns_t_srv: {
382 		u_int priority, weight, port;
383 		char t[50];
384 
385 		if (rdlen < 3U*NS_INT16SZ)
386 			goto formerr;
387 
388 		/* Priority, Weight, Port. */
389 		priority = ns_get16(rdata);  rdata += NS_INT16SZ;
390 		weight   = ns_get16(rdata);  rdata += NS_INT16SZ;
391 		port     = ns_get16(rdata);  rdata += NS_INT16SZ;
392 		len = SPRINTF((t, "%u %u %u ", priority, weight, port));
393 		T(addstr(t, len, &buf, &buflen));
394 
395 		/* Server. */
396 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
397 		break;
398 	    }
399 
400 	case ns_t_minfo:
401 	case ns_t_rp:
402 		/* Name1. */
403 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
404 		T(addstr(" ", 1, &buf, &buflen));
405 
406 		/* Name2. */
407 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
408 
409 		break;
410 
411 	case ns_t_wks: {
412 		int n, lcnt;
413 
414 		if (rdlen < 1U + NS_INT32SZ)
415 			goto formerr;
416 
417 		/* Address. */
418 		(void) inet_ntop(AF_INET, rdata, buf, buflen);
419 		addlen(strlen(buf), &buf, &buflen);
420 		rdata += NS_INADDRSZ;
421 
422 		/* Protocol. */
423 		len = SPRINTF((tmp, " %u ( ", *rdata));
424 		T(addstr(tmp, len, &buf, &buflen));
425 		rdata += NS_INT8SZ;
426 
427 		/* Bit map. */
428 		n = 0;
429 		lcnt = 0;
430 		while (rdata < edata) {
431 			u_int c = *rdata++;
432 			do {
433 				if (c & 0200) {
434 					if (lcnt == 0) {
435 						T(addstr("\n\t\t\t\t", 5,
436 							 &buf, &buflen));
437 						lcnt = 10;
438 						spaced = 0;
439 					}
440 					len = SPRINTF((tmp, "%d ", n));
441 					T(addstr(tmp, len, &buf, &buflen));
442 					lcnt--;
443 				}
444 				c <<= 1;
445 			} while (++n & 07);
446 		}
447 		T(addstr(")", 1, &buf, &buflen));
448 
449 		break;
450 	    }
451 
452 	case ns_t_key: {
453 		char base64_key[NS_MD5RSA_MAX_BASE64];
454 		u_int keyflags, protocol, algorithm, key_id;
455 		const char *leader;
456 		int n;
457 
458 		if (rdlen < 0U + NS_INT16SZ + NS_INT8SZ + NS_INT8SZ)
459 			goto formerr;
460 
461 		/* Key flags, Protocol, Algorithm. */
462 #ifndef _LIBC
463 		key_id = dst_s_dns_key_id(rdata, edata-rdata);
464 #else
465 		key_id = 0;
466 #endif
467 		keyflags = ns_get16(rdata);  rdata += NS_INT16SZ;
468 		protocol = *rdata++;
469 		algorithm = *rdata++;
470 		len = SPRINTF((tmp, "0x%04x %u %u",
471 			       keyflags, protocol, algorithm));
472 		T(addstr(tmp, len, &buf, &buflen));
473 
474 		/* Public key data. */
475 		len = b64_ntop(rdata, edata - rdata,
476 			       base64_key, sizeof base64_key);
477 		if (len < 0)
478 			goto formerr;
479 		if (len > 15) {
480 			T(addstr(" (", 2, &buf, &buflen));
481 			leader = "\n\t\t";
482 			spaced = 0;
483 		} else
484 			leader = " ";
485 		for (n = 0; n < len; n += 48) {
486 			T(addstr(leader, strlen(leader), &buf, &buflen));
487 			T(addstr(base64_key + n, MIN(len - n, 48),
488 				 &buf, &buflen));
489 		}
490 		if (len > 15)
491 			T(addstr(" )", 2, &buf, &buflen));
492 		n = SPRINTF((tmp, " ; key_tag= %u", key_id));
493 		T(addstr(tmp, n, &buf, &buflen));
494 
495 		break;
496 	    }
497 
498 	case ns_t_sig: {
499 		char base64_key[NS_MD5RSA_MAX_BASE64];
500 		u_int type, algorithm, labels, footprint;
501 		const char *leader;
502 		u_long t;
503 		int n;
504 
505 		if (rdlen < 22U)
506 			goto formerr;
507 
508 		/* Type covered, Algorithm, Label count, Original TTL. */
509 	        type = ns_get16(rdata);  rdata += NS_INT16SZ;
510 		algorithm = *rdata++;
511 		labels = *rdata++;
512 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
513 		len = SPRINTF((tmp, "%s %d %d %lu ",
514 			       p_type(type), algorithm, labels, t));
515 		T(addstr(tmp, len, &buf, &buflen));
516 		if (labels > (u_int)dn_count_labels(name))
517 			goto formerr;
518 
519 		/* Signature expiry. */
520 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
521 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
522 		T(addstr(tmp, len, &buf, &buflen));
523 
524 		/* Time signed. */
525 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
526 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
527 		T(addstr(tmp, len, &buf, &buflen));
528 
529 		/* Signature Footprint. */
530 		footprint = ns_get16(rdata);  rdata += NS_INT16SZ;
531 		len = SPRINTF((tmp, "%u ", footprint));
532 		T(addstr(tmp, len, &buf, &buflen));
533 
534 		/* Signer's name. */
535 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
536 
537 		/* Signature. */
538 		len = b64_ntop(rdata, edata - rdata,
539 			       base64_key, sizeof base64_key);
540 		if (len > 15) {
541 			T(addstr(" (", 2, &buf, &buflen));
542 			leader = "\n\t\t";
543 			spaced = 0;
544 		} else
545 			leader = " ";
546 		if (len < 0)
547 			goto formerr;
548 		for (n = 0; n < len; n += 48) {
549 			T(addstr(leader, strlen(leader), &buf, &buflen));
550 			T(addstr(base64_key + n, MIN(len - n, 48),
551 				 &buf, &buflen));
552 		}
553 		if (len > 15)
554 			T(addstr(" )", 2, &buf, &buflen));
555 		break;
556 	    }
557 
558 	case ns_t_nxt: {
559 		int n, c;
560 
561 		/* Next domain name. */
562 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
563 
564 		/* Type bit map. */
565 		n = edata - rdata;
566 		for (c = 0; c < n*8; c++)
567 			if (NS_NXT_BIT_ISSET(c, rdata)) {
568 				len = SPRINTF((tmp, " %s", p_type(c)));
569 				T(addstr(tmp, len, &buf, &buflen));
570 			}
571 		break;
572 	    }
573 
574 	case ns_t_cert: {
575 		u_int c_type, key_tag, alg;
576 		int n;
577 		unsigned int siz;
578 		char base64_cert[8192], tmp[40];
579 		const char *leader;
580 
581 		c_type  = ns_get16(rdata); rdata += NS_INT16SZ;
582 		key_tag = ns_get16(rdata); rdata += NS_INT16SZ;
583 		alg = (u_int) *rdata++;
584 
585 		len = SPRINTF((tmp, "%d %d %d ", c_type, key_tag, alg));
586 		T(addstr(tmp, len, &buf, &buflen));
587 		siz = (edata-rdata)*4/3 + 4; /* "+4" accounts for trailing \0 */
588 		if (siz > sizeof(base64_cert) * 3/4) {
589 			const char *str = "record too long to print";
590 			T(addstr(str, strlen(str), &buf, &buflen));
591 		}
592 		else {
593 			len = b64_ntop(rdata, edata-rdata, base64_cert, siz);
594 
595 			if (len < 0)
596 				goto formerr;
597 			else if (len > 15) {
598 				T(addstr(" (", 2, &buf, &buflen));
599 				leader = "\n\t\t";
600 				spaced = 0;
601 			}
602 			else
603 				leader = " ";
604 
605 			for (n = 0; n < len; n += 48) {
606 				T(addstr(leader, strlen(leader),
607 					 &buf, &buflen));
608 				T(addstr(base64_cert + n, MIN(len - n, 48),
609 					 &buf, &buflen));
610 			}
611 			if (len > 15)
612 				T(addstr(" )", 2, &buf, &buflen));
613 		}
614 		break;
615 	    }
616 
617 	case ns_t_tkey: {
618 		/* KJD - need to complete this */
619 		u_long t;
620 		int mode, err, keysize;
621 
622 		/* Algorithm name. */
623 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
624 		T(addstr(" ", 1, &buf, &buflen));
625 
626 		/* Inception. */
627 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
628 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
629 		T(addstr(tmp, len, &buf, &buflen));
630 
631 		/* Experation. */
632 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
633 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
634 		T(addstr(tmp, len, &buf, &buflen));
635 
636 		/* Mode , Error, Key Size. */
637 		/* Priority, Weight, Port. */
638 		mode = ns_get16(rdata);  rdata += NS_INT16SZ;
639 		err  = ns_get16(rdata);  rdata += NS_INT16SZ;
640 		keysize  = ns_get16(rdata);  rdata += NS_INT16SZ;
641 		len = SPRINTF((tmp, "%u %u %u ", mode, err, keysize));
642 		T(addstr(tmp, len, &buf, &buflen));
643 
644 		/* XXX need to dump key, print otherdata length & other data */
645 		break;
646 	    }
647 
648 	case ns_t_tsig: {
649 		/* BEW - need to complete this */
650 		int n;
651 
652 		T(len = addname(msg, msglen, &rdata, origin, &buf, &buflen));
653 		T(addstr(" ", 1, &buf, &buflen));
654 		rdata += 8; /*%< time */
655 		n = ns_get16(rdata); rdata += INT16SZ;
656 		rdata += n; /*%< sig */
657 		n = ns_get16(rdata); rdata += INT16SZ; /*%< original id */
658 		sprintf(buf, "%d", ns_get16(rdata));
659 		rdata += INT16SZ;
660 		addlen(strlen(buf), &buf, &buflen);
661 		break;
662 	    }
663 
664 	case ns_t_a6: {
665 		struct in6_addr a;
666 		int pbyte, pbit;
667 
668 		/* prefix length */
669 		if (rdlen == 0U) goto formerr;
670 		len = SPRINTF((tmp, "%d ", *rdata));
671 		T(addstr(tmp, len, &buf, &buflen));
672 		pbit = *rdata;
673 		if (pbit > 128) goto formerr;
674 		pbyte = (pbit & ~7) / 8;
675 		rdata++;
676 
677 		/* address suffix: provided only when prefix len != 128 */
678 		if (pbit < 128) {
679 			if (rdata + pbyte >= edata) goto formerr;
680 			memset(&a, 0, sizeof(a));
681 			memcpy(&a.s6_addr[pbyte], rdata, sizeof(a) - pbyte);
682 			(void) inet_ntop(AF_INET6, &a, buf, buflen);
683 			addlen(strlen(buf), &buf, &buflen);
684 			rdata += sizeof(a) - pbyte;
685 		}
686 
687 		/* prefix name: provided only when prefix len > 0 */
688 		if (pbit == 0)
689 			break;
690 		if (rdata >= edata) goto formerr;
691 		T(addstr(" ", 1, &buf, &buflen));
692 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
693 
694 		break;
695 	    }
696 
697 	case ns_t_opt: {
698 		len = SPRINTF((tmp, "%u bytes", class));
699 		T(addstr(tmp, len, &buf, &buflen));
700 		break;
701 	    }
702 
703 	default:
704 		comment = "unknown RR type";
705 		goto hexify;
706 	}
707 	return (buf - obuf);
708  formerr:
709 	comment = "RR format error";
710  hexify: {
711 	int n, m;
712 	char *p;
713 
714 	len = SPRINTF((tmp, "\\# %u%s\t; %s", (unsigned)(edata - rdata),
715 		       rdlen != 0U ? " (" : "", comment));
716 	T(addstr(tmp, len, &buf, &buflen));
717 	while (rdata < edata) {
718 		p = tmp;
719 		p += SPRINTF((p, "\n\t"));
720 		spaced = 0;
721 		n = MIN(16, edata - rdata);
722 		for (m = 0; m < n; m++)
723 			p += SPRINTF((p, "%02x ", rdata[m]));
724 		T(addstr(tmp, p - tmp, &buf, &buflen));
725 		if (n < 16) {
726 			T(addstr(")", 1, &buf, &buflen));
727 			T(addtab(p - tmp + 1, 48, spaced, &buf, &buflen));
728 		}
729 		p = tmp;
730 		p += SPRINTF((p, "; "));
731 		for (m = 0; m < n; m++)
732 			*p++ = (isascii(rdata[m]) && isprint(rdata[m]))
733 				? rdata[m]
734 				: '.';
735 		T(addstr(tmp, p - tmp, &buf, &buflen));
736 		rdata += n;
737 	}
738 	return (buf - obuf);
739     }
740 }
741 
742 /* Private. */
743 
744 /*%
745  * size_t
746  * prune_origin(name, origin)
747  *	Find out if the name is at or under the current origin.
748  * return:
749  *	Number of characters in name before start of origin,
750  *	or length of name if origin does not match.
751  * notes:
752  *	This function should share code with samedomain().
753  */
754 static size_t
755 prune_origin(const char *name, const char *origin) {
756 	const char *oname = name;
757 
758 	while (*name != '\0') {
759 		if (origin != NULL && ns_samename(name, origin) == 1)
760 			return (name - oname - (name > oname));
761 		while (*name != '\0') {
762 			if (*name == '\\') {
763 				name++;
764 				/* XXX need to handle \nnn form. */
765 				if (*name == '\0')
766 					break;
767 			} else if (*name == '.') {
768 				name++;
769 				break;
770 			}
771 			name++;
772 		}
773 	}
774 	return (name - oname);
775 }
776 
777 /*%
778  * int
779  * charstr(rdata, edata, buf, buflen)
780  *	Format a <character-string> into the presentation buffer.
781  * return:
782  *	Number of rdata octets consumed
783  *	0 for protocol format error
784  *	-1 for output buffer error
785  * side effects:
786  *	buffer is advanced on success.
787  */
788 static int
789 charstr(const u_char *rdata, const u_char *edata, char **buf, size_t *buflen) {
790 	const u_char *odata = rdata;
791 	size_t save_buflen = *buflen;
792 	char *save_buf = *buf;
793 
794 	if (addstr("\"", 1, buf, buflen) < 0)
795 		goto enospc;
796 	if (rdata < edata) {
797 		int n = *rdata;
798 
799 		if (rdata + 1 + n <= edata) {
800 			rdata++;
801 			while (n-- > 0) {
802 				if (strchr("\n\"\\", *rdata) != NULL)
803 					if (addstr("\\", 1, buf, buflen) < 0)
804 						goto enospc;
805 				if (addstr((const char *)rdata, 1,
806 					   buf, buflen) < 0)
807 					goto enospc;
808 				rdata++;
809 			}
810 		}
811 	}
812 	if (addstr("\"", 1, buf, buflen) < 0)
813 		goto enospc;
814 	return (rdata - odata);
815  enospc:
816 	errno = ENOSPC;
817 	*buf = save_buf;
818 	*buflen = save_buflen;
819 	return (-1);
820 }
821 
822 static int
823 addname(const u_char *msg, size_t msglen,
824 	const u_char **pp, const char *origin,
825 	char **buf, size_t *buflen)
826 {
827 	size_t newlen, save_buflen = *buflen;
828 	char *save_buf = *buf;
829 	int n;
830 
831 	n = dn_expand(msg, msg + msglen, *pp, *buf, *buflen);
832 	if (n < 0)
833 		goto enospc;	/*%< Guess. */
834 	newlen = prune_origin(*buf, origin);
835 	if (**buf == '\0') {
836 		goto root;
837 	} else if (newlen == 0U) {
838 		/* Use "@" instead of name. */
839 		if (newlen + 2 > *buflen)
840 			goto enospc;        /* No room for "@\0". */
841 		(*buf)[newlen++] = '@';
842 		(*buf)[newlen] = '\0';
843 	} else {
844 		if (((origin == NULL || origin[0] == '\0') ||
845 		    (origin[0] != '.' && origin[1] != '\0' &&
846 		    (*buf)[newlen] == '\0')) && (*buf)[newlen - 1] != '.') {
847 			/* No trailing dot. */
848  root:
849 			if (newlen + 2 > *buflen)
850 				goto enospc;	/* No room for ".\0". */
851 			(*buf)[newlen++] = '.';
852 			(*buf)[newlen] = '\0';
853 		}
854 	}
855 	*pp += n;
856 	addlen(newlen, buf, buflen);
857 	**buf = '\0';
858 	return (newlen);
859  enospc:
860 	errno = ENOSPC;
861 	*buf = save_buf;
862 	*buflen = save_buflen;
863 	return (-1);
864 }
865 
866 static void
867 addlen(size_t len, char **buf, size_t *buflen) {
868 	INSIST(len <= *buflen);
869 	*buf += len;
870 	*buflen -= len;
871 }
872 
873 static int
874 addstr(const char *src, size_t len, char **buf, size_t *buflen) {
875 	if (len >= *buflen) {
876 		errno = ENOSPC;
877 		return (-1);
878 	}
879 	memcpy(*buf, src, len);
880 	addlen(len, buf, buflen);
881 	**buf = '\0';
882 	return (0);
883 }
884 
885 static int
886 addtab(size_t len, size_t target, int spaced, char **buf, size_t *buflen) {
887 	size_t save_buflen = *buflen;
888 	char *save_buf = *buf;
889 	int t;
890 
891 	if (spaced || len >= target - 1) {
892 		T(addstr("  ", 2, buf, buflen));
893 		spaced = 1;
894 	} else {
895 		for (t = (target - len - 1) / 8; t >= 0; t--)
896 			if (addstr("\t", 1, buf, buflen) < 0) {
897 				*buflen = save_buflen;
898 				*buf = save_buf;
899 				return (-1);
900 			}
901 		spaced = 0;
902 	}
903 	return (spaced);
904 }
905 
906 /*! \file */
907