xref: /dragonfly/lib/libc/nameser/ns_print.c (revision 92c825d6)
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  * $Id: ns_print.c,v 1.10 2005/04/27 04:56:40 sra Exp $
18  */
19 
20 /* Import. */
21 
22 #include "port_before.h"
23 
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 
27 #include <netinet/in.h>
28 #include <arpa/nameser.h>
29 #include <arpa/inet.h>
30 
31 #ifdef _LIBC
32 #include <assert.h>
33 #define INSIST(cond)   assert(cond)
34 #else
35 #include <isc/assertions.h>
36 #include <isc/dst.h>
37 #endif
38 #include <errno.h>
39 #include <resolv.h>
40 #include <string.h>
41 #include <ctype.h>
42 
43 #include "port_after.h"
44 
45 #ifdef SPRINTF_CHAR
46 # define SPRINTF(x) strlen(sprintf/**/x)
47 #else
48 # define SPRINTF(x) ((size_t)sprintf x)
49 #endif
50 
51 /* Forward. */
52 
53 static size_t	prune_origin(const char *name, const char *origin);
54 static int	charstr(const u_char *rdata, const u_char *edata,
55 			char **buf, size_t *buflen);
56 static int	addname(const u_char *msg, size_t msglen,
57 			const u_char **p, const char *origin,
58 			char **buf, size_t *buflen);
59 static void	addlen(size_t len, char **buf, size_t *buflen);
60 static int	addstr(const char *src, size_t len,
61 		       char **buf, size_t *buflen);
62 static int	addtab(size_t len, size_t target, int spaced,
63 		       char **buf, size_t *buflen);
64 
65 /* Macros. */
66 
67 #define	T(x) \
68 	do { \
69 		if ((x) < 0) \
70 			return (-1); \
71 	} while (0)
72 
73 /* Public. */
74 
75 /*%
76  *	Convert an RR to presentation format.
77  *
78  * return:
79  *\li	Number of characters written to buf, or -1 (check errno).
80  */
81 int
82 ns_sprintrr(const ns_msg *handle, const ns_rr *rr,
83 	    const char *name_ctx, const char *origin,
84 	    char *buf, size_t buflen)
85 {
86 	int n;
87 
88 	n = ns_sprintrrf(ns_msg_base(*handle), ns_msg_size(*handle),
89 			 ns_rr_name(*rr), ns_rr_class(*rr), ns_rr_type(*rr),
90 			 ns_rr_ttl(*rr), ns_rr_rdata(*rr), ns_rr_rdlen(*rr),
91 			 name_ctx, origin, buf, buflen);
92 	return (n);
93 }
94 
95 /*%
96  *	Convert the fields of an RR into presentation format.
97  *
98  * return:
99  *\li	Number of characters written to buf, or -1 (check errno).
100  */
101 int
102 ns_sprintrrf(const u_char *msg, size_t msglen,
103 	    const char *name, ns_class class, ns_type type,
104 	    u_long ttl, const u_char *rdata, size_t rdlen,
105 	    const char *name_ctx, const char *origin,
106 	    char *buf, size_t buflen)
107 {
108 	const char *obuf = buf;
109 	const u_char *edata = rdata + rdlen;
110 	int spaced = 0;
111 
112 	const char *comment;
113 	char tmp[100];
114 	int len, x;
115 
116 	/*
117 	 * Owner.
118 	 */
119 	if (name_ctx != NULL && ns_samename(name_ctx, name) == 1) {
120 		T(addstr("\t\t\t", 3, &buf, &buflen));
121 	} else {
122 		len = prune_origin(name, origin);
123 		if (*name == '\0') {
124 			goto root;
125 		} else if (len == 0) {
126 			T(addstr("@\t\t\t", 4, &buf, &buflen));
127 		} else {
128 			T(addstr(name, len, &buf, &buflen));
129 			/* Origin not used or not root, and no trailing dot? */
130 			if (((origin == NULL || origin[0] == '\0') ||
131 			    (origin[0] != '.' && origin[1] != '\0' &&
132 			    name[len] == '\0')) && name[len - 1] != '.') {
133  root:
134 				T(addstr(".", 1, &buf, &buflen));
135 				len++;
136 			}
137 			T(spaced = addtab(len, 24, spaced, &buf, &buflen));
138 		}
139 	}
140 
141 	/*
142 	 * TTL, Class, Type.
143 	 */
144 	T(x = ns_format_ttl(ttl, buf, buflen));
145 	addlen(x, &buf, &buflen);
146 	len = SPRINTF((tmp, " %s %s", p_class(class), p_type(type)));
147 	T(addstr(tmp, len, &buf, &buflen));
148 	T(spaced = addtab(x + len, 16, spaced, &buf, &buflen));
149 
150 	/*
151 	 * RData.
152 	 */
153 	switch (type) {
154 	case ns_t_a:
155 		if (rdlen != (size_t)NS_INADDRSZ)
156 			goto formerr;
157 		(void) inet_ntop(AF_INET, rdata, buf, buflen);
158 		addlen(strlen(buf), &buf, &buflen);
159 		break;
160 
161 	case ns_t_cname:
162 	case ns_t_mb:
163 	case ns_t_mg:
164 	case ns_t_mr:
165 	case ns_t_ns:
166 	case ns_t_ptr:
167 	case ns_t_dname:
168 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
169 		break;
170 
171 	case ns_t_hinfo:
172 	case ns_t_isdn:
173 		/* First word. */
174 		T(len = charstr(rdata, edata, &buf, &buflen));
175 		if (len == 0)
176 			goto formerr;
177 		rdata += len;
178 		T(addstr(" ", 1, &buf, &buflen));
179 
180 
181 		/* Second word, optional in ISDN records. */
182 		if (type == ns_t_isdn && rdata == edata)
183 			break;
184 
185 		T(len = charstr(rdata, edata, &buf, &buflen));
186 		if (len == 0)
187 			goto formerr;
188 		rdata += len;
189 		break;
190 
191 	case ns_t_soa: {
192 		u_long t;
193 
194 		/* Server name. */
195 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
196 		T(addstr(" ", 1, &buf, &buflen));
197 
198 		/* Administrator name. */
199 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
200 		T(addstr(" (\n", 3, &buf, &buflen));
201 		spaced = 0;
202 
203 		if ((edata - rdata) != 5*NS_INT32SZ)
204 			goto formerr;
205 
206 		/* Serial number. */
207 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
208 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
209 		len = SPRINTF((tmp, "%lu", t));
210 		T(addstr(tmp, len, &buf, &buflen));
211 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
212 		T(addstr("; serial\n", 9, &buf, &buflen));
213 		spaced = 0;
214 
215 		/* Refresh interval. */
216 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
217 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
218 		T(len = ns_format_ttl(t, buf, buflen));
219 		addlen(len, &buf, &buflen);
220 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
221 		T(addstr("; refresh\n", 10, &buf, &buflen));
222 		spaced = 0;
223 
224 		/* Retry interval. */
225 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
226 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
227 		T(len = ns_format_ttl(t, buf, buflen));
228 		addlen(len, &buf, &buflen);
229 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
230 		T(addstr("; retry\n", 8, &buf, &buflen));
231 		spaced = 0;
232 
233 		/* Expiry. */
234 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
235 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
236 		T(len = ns_format_ttl(t, buf, buflen));
237 		addlen(len, &buf, &buflen);
238 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
239 		T(addstr("; expiry\n", 9, &buf, &buflen));
240 		spaced = 0;
241 
242 		/* Minimum TTL. */
243 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
244 		T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
245 		T(len = ns_format_ttl(t, buf, buflen));
246 		addlen(len, &buf, &buflen);
247 		T(addstr(" )", 2, &buf, &buflen));
248 		T(spaced = addtab(len, 16, spaced, &buf, &buflen));
249 		T(addstr("; minimum\n", 10, &buf, &buflen));
250 
251 		break;
252 	    }
253 
254 	case ns_t_mx:
255 	case ns_t_afsdb:
256 	case ns_t_rt: {
257 		u_int t;
258 
259 		if (rdlen < (size_t)NS_INT16SZ)
260 			goto formerr;
261 
262 		/* Priority. */
263 		t = ns_get16(rdata);
264 		rdata += NS_INT16SZ;
265 		len = SPRINTF((tmp, "%u ", t));
266 		T(addstr(tmp, len, &buf, &buflen));
267 
268 		/* Target. */
269 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
270 
271 		break;
272 	    }
273 
274 	case ns_t_px: {
275 		u_int t;
276 
277 		if (rdlen < (size_t)NS_INT16SZ)
278 			goto formerr;
279 
280 		/* Priority. */
281 		t = ns_get16(rdata);
282 		rdata += NS_INT16SZ;
283 		len = SPRINTF((tmp, "%u ", t));
284 		T(addstr(tmp, len, &buf, &buflen));
285 
286 		/* Name1. */
287 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
288 		T(addstr(" ", 1, &buf, &buflen));
289 
290 		/* Name2. */
291 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
292 
293 		break;
294 	    }
295 
296 	case ns_t_x25:
297 		T(len = charstr(rdata, edata, &buf, &buflen));
298 		if (len == 0)
299 			goto formerr;
300 		rdata += len;
301 		break;
302 
303 	case ns_t_txt:
304 		while (rdata < edata) {
305 			T(len = charstr(rdata, edata, &buf, &buflen));
306 			if (len == 0)
307 				goto formerr;
308 			rdata += len;
309 			if (rdata < edata)
310 				T(addstr(" ", 1, &buf, &buflen));
311 		}
312 		break;
313 
314 	case ns_t_nsap: {
315 		char t[2+255*3];
316 
317 		(void) inet_nsap_ntoa(rdlen, rdata, t);
318 		T(addstr(t, strlen(t), &buf, &buflen));
319 		break;
320 	    }
321 
322 	case ns_t_aaaa:
323 		if (rdlen != (size_t)NS_IN6ADDRSZ)
324 			goto formerr;
325 		(void) inet_ntop(AF_INET6, rdata, buf, buflen);
326 		addlen(strlen(buf), &buf, &buflen);
327 		break;
328 
329 	case ns_t_loc: {
330 		char t[255];
331 
332 		/* XXX protocol format checking? */
333 		(void) loc_ntoa(rdata, t);
334 		T(addstr(t, strlen(t), &buf, &buflen));
335 		break;
336 	    }
337 
338 	case ns_t_naptr: {
339 		u_int order, preference;
340 		char t[50];
341 
342 		if (rdlen < 2U*NS_INT16SZ)
343 			goto formerr;
344 
345 		/* Order, Precedence. */
346 		order = ns_get16(rdata);	rdata += NS_INT16SZ;
347 		preference = ns_get16(rdata);	rdata += NS_INT16SZ;
348 		len = SPRINTF((t, "%u %u ", order, preference));
349 		T(addstr(t, len, &buf, &buflen));
350 
351 		/* Flags. */
352 		T(len = charstr(rdata, edata, &buf, &buflen));
353 		if (len == 0)
354 			goto formerr;
355 		rdata += len;
356 		T(addstr(" ", 1, &buf, &buflen));
357 
358 		/* Service. */
359 		T(len = charstr(rdata, edata, &buf, &buflen));
360 		if (len == 0)
361 			goto formerr;
362 		rdata += len;
363 		T(addstr(" ", 1, &buf, &buflen));
364 
365 		/* Regexp. */
366 		T(len = charstr(rdata, edata, &buf, &buflen));
367 		if (len < 0)
368 			return (-1);
369 		if (len == 0)
370 			goto formerr;
371 		rdata += len;
372 		T(addstr(" ", 1, &buf, &buflen));
373 
374 		/* Server. */
375 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
376 		break;
377 	    }
378 
379 	case ns_t_srv: {
380 		u_int priority, weight, port;
381 		char t[50];
382 
383 		if (rdlen < 3U*NS_INT16SZ)
384 			goto formerr;
385 
386 		/* Priority, Weight, Port. */
387 		priority = ns_get16(rdata);  rdata += NS_INT16SZ;
388 		weight   = ns_get16(rdata);  rdata += NS_INT16SZ;
389 		port     = ns_get16(rdata);  rdata += NS_INT16SZ;
390 		len = SPRINTF((t, "%u %u %u ", priority, weight, port));
391 		T(addstr(t, len, &buf, &buflen));
392 
393 		/* Server. */
394 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
395 		break;
396 	    }
397 
398 	case ns_t_minfo:
399 	case ns_t_rp:
400 		/* Name1. */
401 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
402 		T(addstr(" ", 1, &buf, &buflen));
403 
404 		/* Name2. */
405 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
406 
407 		break;
408 
409 	case ns_t_wks: {
410 		int n, lcnt;
411 
412 		if (rdlen < 1U + NS_INT32SZ)
413 			goto formerr;
414 
415 		/* Address. */
416 		(void) inet_ntop(AF_INET, rdata, buf, buflen);
417 		addlen(strlen(buf), &buf, &buflen);
418 		rdata += NS_INADDRSZ;
419 
420 		/* Protocol. */
421 		len = SPRINTF((tmp, " %u ( ", *rdata));
422 		T(addstr(tmp, len, &buf, &buflen));
423 		rdata += NS_INT8SZ;
424 
425 		/* Bit map. */
426 		n = 0;
427 		lcnt = 0;
428 		while (rdata < edata) {
429 			u_int c = *rdata++;
430 			do {
431 				if (c & 0200) {
432 					if (lcnt == 0) {
433 						T(addstr("\n\t\t\t\t", 5,
434 							 &buf, &buflen));
435 						lcnt = 10;
436 						spaced = 0;
437 					}
438 					len = SPRINTF((tmp, "%d ", n));
439 					T(addstr(tmp, len, &buf, &buflen));
440 					lcnt--;
441 				}
442 				c <<= 1;
443 			} while (++n & 07);
444 		}
445 		T(addstr(")", 1, &buf, &buflen));
446 
447 		break;
448 	    }
449 
450 	case ns_t_key: {
451 		char base64_key[NS_MD5RSA_MAX_BASE64];
452 		u_int keyflags, protocol, algorithm, key_id;
453 		const char *leader;
454 		int n;
455 
456 		if (rdlen < 0U + NS_INT16SZ + NS_INT8SZ + NS_INT8SZ)
457 			goto formerr;
458 
459 		/* Key flags, Protocol, Algorithm. */
460 #ifndef _LIBC
461 		key_id = dst_s_dns_key_id(rdata, edata-rdata);
462 #else
463 		key_id = 0;
464 #endif
465 		keyflags = ns_get16(rdata);  rdata += NS_INT16SZ;
466 		protocol = *rdata++;
467 		algorithm = *rdata++;
468 		len = SPRINTF((tmp, "0x%04x %u %u",
469 			       keyflags, protocol, algorithm));
470 		T(addstr(tmp, len, &buf, &buflen));
471 
472 		/* Public key data. */
473 		len = b64_ntop(rdata, edata - rdata,
474 			       base64_key, sizeof base64_key);
475 		if (len < 0)
476 			goto formerr;
477 		if (len > 15) {
478 			T(addstr(" (", 2, &buf, &buflen));
479 			leader = "\n\t\t";
480 			spaced = 0;
481 		} else
482 			leader = " ";
483 		for (n = 0; n < len; n += 48) {
484 			T(addstr(leader, strlen(leader), &buf, &buflen));
485 			T(addstr(base64_key + n, MIN(len - n, 48),
486 				 &buf, &buflen));
487 		}
488 		if (len > 15)
489 			T(addstr(" )", 2, &buf, &buflen));
490 		n = SPRINTF((tmp, " ; key_tag= %u", key_id));
491 		T(addstr(tmp, n, &buf, &buflen));
492 
493 		break;
494 	    }
495 
496 	case ns_t_sig: {
497 		char base64_key[NS_MD5RSA_MAX_BASE64];
498 		u_int type, algorithm, labels, footprint;
499 		const char *leader;
500 		u_long t;
501 		int n;
502 
503 		if (rdlen < 22U)
504 			goto formerr;
505 
506 		/* Type covered, Algorithm, Label count, Original TTL. */
507 	        type = ns_get16(rdata);  rdata += NS_INT16SZ;
508 		algorithm = *rdata++;
509 		labels = *rdata++;
510 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
511 		len = SPRINTF((tmp, "%s %d %d %lu ",
512 			       p_type(type), algorithm, labels, t));
513 		T(addstr(tmp, len, &buf, &buflen));
514 		if (labels > (u_int)dn_count_labels(name))
515 			goto formerr;
516 
517 		/* Signature expiry. */
518 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
519 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
520 		T(addstr(tmp, len, &buf, &buflen));
521 
522 		/* Time signed. */
523 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
524 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
525 		T(addstr(tmp, len, &buf, &buflen));
526 
527 		/* Signature Footprint. */
528 		footprint = ns_get16(rdata);  rdata += NS_INT16SZ;
529 		len = SPRINTF((tmp, "%u ", footprint));
530 		T(addstr(tmp, len, &buf, &buflen));
531 
532 		/* Signer's name. */
533 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
534 
535 		/* Signature. */
536 		len = b64_ntop(rdata, edata - rdata,
537 			       base64_key, sizeof base64_key);
538 		if (len > 15) {
539 			T(addstr(" (", 2, &buf, &buflen));
540 			leader = "\n\t\t";
541 			spaced = 0;
542 		} else
543 			leader = " ";
544 		if (len < 0)
545 			goto formerr;
546 		for (n = 0; n < len; n += 48) {
547 			T(addstr(leader, strlen(leader), &buf, &buflen));
548 			T(addstr(base64_key + n, MIN(len - n, 48),
549 				 &buf, &buflen));
550 		}
551 		if (len > 15)
552 			T(addstr(" )", 2, &buf, &buflen));
553 		break;
554 	    }
555 
556 	case ns_t_nxt: {
557 		int n, c;
558 
559 		/* Next domain name. */
560 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
561 
562 		/* Type bit map. */
563 		n = edata - rdata;
564 		for (c = 0; c < n*8; c++)
565 			if (NS_NXT_BIT_ISSET(c, rdata)) {
566 				len = SPRINTF((tmp, " %s", p_type(c)));
567 				T(addstr(tmp, len, &buf, &buflen));
568 			}
569 		break;
570 	    }
571 
572 	case ns_t_cert: {
573 		u_int c_type, key_tag, alg;
574 		int n;
575 		unsigned int siz;
576 		char base64_cert[8192], tmp[40];
577 		const char *leader;
578 
579 		c_type  = ns_get16(rdata); rdata += NS_INT16SZ;
580 		key_tag = ns_get16(rdata); rdata += NS_INT16SZ;
581 		alg = (u_int) *rdata++;
582 
583 		len = SPRINTF((tmp, "%d %d %d ", c_type, key_tag, alg));
584 		T(addstr(tmp, len, &buf, &buflen));
585 		siz = (edata-rdata)*4/3 + 4; /* "+4" accounts for trailing \0 */
586 		if (siz > sizeof(base64_cert) * 3/4) {
587 			const char *str = "record too long to print";
588 			T(addstr(str, strlen(str), &buf, &buflen));
589 		}
590 		else {
591 			len = b64_ntop(rdata, edata-rdata, base64_cert, siz);
592 
593 			if (len < 0)
594 				goto formerr;
595 			else if (len > 15) {
596 				T(addstr(" (", 2, &buf, &buflen));
597 				leader = "\n\t\t";
598 				spaced = 0;
599 			}
600 			else
601 				leader = " ";
602 
603 			for (n = 0; n < len; n += 48) {
604 				T(addstr(leader, strlen(leader),
605 					 &buf, &buflen));
606 				T(addstr(base64_cert + n, MIN(len - n, 48),
607 					 &buf, &buflen));
608 			}
609 			if (len > 15)
610 				T(addstr(" )", 2, &buf, &buflen));
611 		}
612 		break;
613 	    }
614 
615 	case ns_t_tkey: {
616 		/* KJD - need to complete this */
617 		u_long t;
618 		int mode, err, keysize;
619 
620 		/* Algorithm name. */
621 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
622 		T(addstr(" ", 1, &buf, &buflen));
623 
624 		/* Inception. */
625 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
626 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
627 		T(addstr(tmp, len, &buf, &buflen));
628 
629 		/* Experation. */
630 		t = ns_get32(rdata);  rdata += NS_INT32SZ;
631 		len = SPRINTF((tmp, "%s ", p_secstodate(t)));
632 		T(addstr(tmp, len, &buf, &buflen));
633 
634 		/* Mode , Error, Key Size. */
635 		/* Priority, Weight, Port. */
636 		mode = ns_get16(rdata);  rdata += NS_INT16SZ;
637 		err  = ns_get16(rdata);  rdata += NS_INT16SZ;
638 		keysize  = ns_get16(rdata);  rdata += NS_INT16SZ;
639 		len = SPRINTF((tmp, "%u %u %u ", mode, err, keysize));
640 		T(addstr(tmp, len, &buf, &buflen));
641 
642 		/* XXX need to dump key, print otherdata length & other data */
643 		break;
644 	    }
645 
646 	case ns_t_tsig: {
647 		/* BEW - need to complete this */
648 		int n;
649 
650 		T(len = addname(msg, msglen, &rdata, origin, &buf, &buflen));
651 		T(addstr(" ", 1, &buf, &buflen));
652 		rdata += 8; /*%< time */
653 		n = ns_get16(rdata); rdata += INT16SZ;
654 		rdata += n; /*%< sig */
655 		n = ns_get16(rdata); rdata += INT16SZ; /*%< original id */
656 		sprintf(buf, "%d", ns_get16(rdata));
657 		rdata += INT16SZ;
658 		addlen(strlen(buf), &buf, &buflen);
659 		break;
660 	    }
661 
662 	case ns_t_a6: {
663 		struct in6_addr a;
664 		int pbyte, pbit;
665 
666 		/* prefix length */
667 		if (rdlen == 0U) goto formerr;
668 		len = SPRINTF((tmp, "%d ", *rdata));
669 		T(addstr(tmp, len, &buf, &buflen));
670 		pbit = *rdata;
671 		if (pbit > 128) goto formerr;
672 		pbyte = (pbit & ~7) / 8;
673 		rdata++;
674 
675 		/* address suffix: provided only when prefix len != 128 */
676 		if (pbit < 128) {
677 			if (rdata + pbyte >= edata) goto formerr;
678 			memset(&a, 0, sizeof(a));
679 			memcpy(&a.s6_addr[pbyte], rdata, sizeof(a) - pbyte);
680 			(void) inet_ntop(AF_INET6, &a, buf, buflen);
681 			addlen(strlen(buf), &buf, &buflen);
682 			rdata += sizeof(a) - pbyte;
683 		}
684 
685 		/* prefix name: provided only when prefix len > 0 */
686 		if (pbit == 0)
687 			break;
688 		if (rdata >= edata) goto formerr;
689 		T(addstr(" ", 1, &buf, &buflen));
690 		T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
691 
692 		break;
693 	    }
694 
695 	case ns_t_opt: {
696 		len = SPRINTF((tmp, "%u bytes", class));
697 		T(addstr(tmp, len, &buf, &buflen));
698 		break;
699 	    }
700 
701 	default:
702 		comment = "unknown RR type";
703 		goto hexify;
704 	}
705 	return (buf - obuf);
706  formerr:
707 	comment = "RR format error";
708  hexify: {
709 	int n, m;
710 	char *p;
711 
712 	len = SPRINTF((tmp, "\\# %u%s\t; %s", (unsigned)(edata - rdata),
713 		       rdlen != 0U ? " (" : "", comment));
714 	T(addstr(tmp, len, &buf, &buflen));
715 	while (rdata < edata) {
716 		p = tmp;
717 		p += SPRINTF((p, "\n\t"));
718 		spaced = 0;
719 		n = MIN(16, edata - rdata);
720 		for (m = 0; m < n; m++)
721 			p += SPRINTF((p, "%02x ", rdata[m]));
722 		T(addstr(tmp, p - tmp, &buf, &buflen));
723 		if (n < 16) {
724 			T(addstr(")", 1, &buf, &buflen));
725 			T(addtab(p - tmp + 1, 48, spaced, &buf, &buflen));
726 		}
727 		p = tmp;
728 		p += SPRINTF((p, "; "));
729 		for (m = 0; m < n; m++)
730 			*p++ = (isascii(rdata[m]) && isprint(rdata[m]))
731 				? rdata[m]
732 				: '.';
733 		T(addstr(tmp, p - tmp, &buf, &buflen));
734 		rdata += n;
735 	}
736 	return (buf - obuf);
737     }
738 }
739 
740 /* Private. */
741 
742 /*%
743  * size_t
744  * prune_origin(name, origin)
745  *	Find out if the name is at or under the current origin.
746  * return:
747  *	Number of characters in name before start of origin,
748  *	or length of name if origin does not match.
749  * notes:
750  *	This function should share code with samedomain().
751  */
752 static size_t
753 prune_origin(const char *name, const char *origin) {
754 	const char *oname = name;
755 
756 	while (*name != '\0') {
757 		if (origin != NULL && ns_samename(name, origin) == 1)
758 			return (name - oname - (name > oname));
759 		while (*name != '\0') {
760 			if (*name == '\\') {
761 				name++;
762 				/* XXX need to handle \nnn form. */
763 				if (*name == '\0')
764 					break;
765 			} else if (*name == '.') {
766 				name++;
767 				break;
768 			}
769 			name++;
770 		}
771 	}
772 	return (name - oname);
773 }
774 
775 /*%
776  * int
777  * charstr(rdata, edata, buf, buflen)
778  *	Format a <character-string> into the presentation buffer.
779  * return:
780  *	Number of rdata octets consumed
781  *	0 for protocol format error
782  *	-1 for output buffer error
783  * side effects:
784  *	buffer is advanced on success.
785  */
786 static int
787 charstr(const u_char *rdata, const u_char *edata, char **buf, size_t *buflen) {
788 	const u_char *odata = rdata;
789 	size_t save_buflen = *buflen;
790 	char *save_buf = *buf;
791 
792 	if (addstr("\"", 1, buf, buflen) < 0)
793 		goto enospc;
794 	if (rdata < edata) {
795 		int n = *rdata;
796 
797 		if (rdata + 1 + n <= edata) {
798 			rdata++;
799 			while (n-- > 0) {
800 				if (strchr("\n\"\\", *rdata) != NULL)
801 					if (addstr("\\", 1, buf, buflen) < 0)
802 						goto enospc;
803 				if (addstr((const char *)rdata, 1,
804 					   buf, buflen) < 0)
805 					goto enospc;
806 				rdata++;
807 			}
808 		}
809 	}
810 	if (addstr("\"", 1, buf, buflen) < 0)
811 		goto enospc;
812 	return (rdata - odata);
813  enospc:
814 	errno = ENOSPC;
815 	*buf = save_buf;
816 	*buflen = save_buflen;
817 	return (-1);
818 }
819 
820 static int
821 addname(const u_char *msg, size_t msglen,
822 	const u_char **pp, const char *origin,
823 	char **buf, size_t *buflen)
824 {
825 	size_t newlen, save_buflen = *buflen;
826 	char *save_buf = *buf;
827 	int n;
828 
829 	n = dn_expand(msg, msg + msglen, *pp, *buf, *buflen);
830 	if (n < 0)
831 		goto enospc;	/*%< Guess. */
832 	newlen = prune_origin(*buf, origin);
833 	if (**buf == '\0') {
834 		goto root;
835 	} else if (newlen == 0U) {
836 		/* Use "@" instead of name. */
837 		if (newlen + 2 > *buflen)
838 			goto enospc;        /* No room for "@\0". */
839 		(*buf)[newlen++] = '@';
840 		(*buf)[newlen] = '\0';
841 	} else {
842 		if (((origin == NULL || origin[0] == '\0') ||
843 		    (origin[0] != '.' && origin[1] != '\0' &&
844 		    (*buf)[newlen] == '\0')) && (*buf)[newlen - 1] != '.') {
845 			/* No trailing dot. */
846  root:
847 			if (newlen + 2 > *buflen)
848 				goto enospc;	/* No room for ".\0". */
849 			(*buf)[newlen++] = '.';
850 			(*buf)[newlen] = '\0';
851 		}
852 	}
853 	*pp += n;
854 	addlen(newlen, buf, buflen);
855 	**buf = '\0';
856 	return (newlen);
857  enospc:
858 	errno = ENOSPC;
859 	*buf = save_buf;
860 	*buflen = save_buflen;
861 	return (-1);
862 }
863 
864 static void
865 addlen(size_t len, char **buf, size_t *buflen) {
866 	INSIST(len <= *buflen);
867 	*buf += len;
868 	*buflen -= len;
869 }
870 
871 static int
872 addstr(const char *src, size_t len, char **buf, size_t *buflen) {
873 	if (len >= *buflen) {
874 		errno = ENOSPC;
875 		return (-1);
876 	}
877 	memcpy(*buf, src, len);
878 	addlen(len, buf, buflen);
879 	**buf = '\0';
880 	return (0);
881 }
882 
883 static int
884 addtab(size_t len, size_t target, int spaced, char **buf, size_t *buflen) {
885 	size_t save_buflen = *buflen;
886 	char *save_buf = *buf;
887 	int t;
888 
889 	if (spaced || len >= target - 1) {
890 		T(addstr("  ", 2, buf, buflen));
891 		spaced = 1;
892 	} else {
893 		for (t = (target - len - 1) / 8; t >= 0; t--)
894 			if (addstr("\t", 1, buf, buflen) < 0) {
895 				*buflen = save_buflen;
896 				*buf = save_buf;
897 				return (-1);
898 			}
899 		spaced = 0;
900 	}
901 	return (spaced);
902 }
903 
904 /*! \file */
905