1/*
2 * dname.c
3 *
4 * dname specific rdata implementations
5 * A dname is a rdf structure with type LDNS_RDF_TYPE_DNAME
6 * It is not a /real/ type! All function must therefor check
7 * for LDNS_RDF_TYPE_DNAME.
8 *
9 * a Net::DNS like library for C
10 *
11 * (c) NLnet Labs, 2004-2006
12 *
13 * See the file LICENSE for the license
14 */
15
16#include <ldns/config.h>
17
18#include <ldns/ldns.h>
19
20#ifdef HAVE_NETINET_IN_H
21#include <netinet/in.h>
22#endif
23#ifdef HAVE_SYS_SOCKET_H
24#include <sys/socket.h>
25#endif
26#ifdef HAVE_NETDB_H
27#include <netdb.h>
28#endif
29#ifdef HAVE_ARPA_INET_H
30#include <arpa/inet.h>
31#endif
32
33/* Returns whether the last label in the name is a root label (a empty label).
34 * Note that it is not enough to just test the last character to be 0,
35 * because it may be part of the last label itself.
36 */
37static bool
38ldns_dname_last_label_is_root_label(const ldns_rdf* dname)
39{
40	size_t src_pos;
41	size_t len = 0;
42
43	for (src_pos = 0; src_pos < ldns_rdf_size(dname); src_pos += len + 1) {
44		len = ldns_rdf_data(dname)[src_pos];
45	}
46	assert(src_pos == ldns_rdf_size(dname));
47
48	return src_pos > 0 && len == 0;
49}
50
51ldns_rdf *
52ldns_dname_cat_clone(const ldns_rdf *rd1, const ldns_rdf *rd2)
53{
54	ldns_rdf *new;
55	uint16_t new_size;
56	uint8_t *buf;
57	uint16_t left_size;
58
59	if (ldns_rdf_get_type(rd1) != LDNS_RDF_TYPE_DNAME ||
60			ldns_rdf_get_type(rd2) != LDNS_RDF_TYPE_DNAME) {
61		return NULL;
62	}
63
64	/* remove root label if it is present at the end of the left
65	 * rd, by reducing the size with 1
66	 */
67	left_size = ldns_rdf_size(rd1);
68	if (ldns_dname_last_label_is_root_label(rd1)) {
69		left_size--;
70	}
71
72	/* we overwrite the nullbyte of rd1 */
73	new_size = left_size + ldns_rdf_size(rd2);
74	buf = LDNS_XMALLOC(uint8_t, new_size);
75	if (!buf) {
76		return NULL;
77	}
78
79	/* put the two dname's after each other */
80	memcpy(buf, ldns_rdf_data(rd1), left_size);
81	memcpy(buf + left_size, ldns_rdf_data(rd2), ldns_rdf_size(rd2));
82
83	new = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, new_size, buf);
84
85	LDNS_FREE(buf);
86	return new;
87}
88
89ldns_status
90ldns_dname_cat(ldns_rdf *rd1, ldns_rdf *rd2)
91{
92	uint16_t left_size;
93	uint16_t size;
94	uint8_t* newd;
95
96	if (ldns_rdf_get_type(rd1) != LDNS_RDF_TYPE_DNAME ||
97			ldns_rdf_get_type(rd2) != LDNS_RDF_TYPE_DNAME) {
98		return LDNS_STATUS_ERR;
99	}
100
101	/* remove root label if it is present at the end of the left
102	 * rd, by reducing the size with 1
103	 */
104	left_size = ldns_rdf_size(rd1);
105	if (ldns_dname_last_label_is_root_label(rd1)) {
106		left_size--;
107	}
108
109	size = left_size + ldns_rdf_size(rd2);
110	newd = LDNS_XREALLOC(ldns_rdf_data(rd1), uint8_t, size);
111	if(!newd) {
112		return LDNS_STATUS_MEM_ERR;
113	}
114
115	ldns_rdf_set_data(rd1, newd);
116	memcpy(ldns_rdf_data(rd1) + left_size, ldns_rdf_data(rd2),
117			ldns_rdf_size(rd2));
118	ldns_rdf_set_size(rd1, size);
119
120	return LDNS_STATUS_OK;
121}
122
123ldns_rdf*
124ldns_dname_reverse(const ldns_rdf *dname)
125{
126	size_t rd_size;
127	uint8_t* buf;
128	ldns_rdf* new;
129	size_t src_pos;
130	size_t len ;
131
132	assert(ldns_rdf_get_type(dname) == LDNS_RDF_TYPE_DNAME);
133
134	rd_size = ldns_rdf_size(dname);
135	buf = LDNS_XMALLOC(uint8_t, rd_size);
136	if (! buf) {
137		return NULL;
138	}
139	new = ldns_rdf_new(LDNS_RDF_TYPE_DNAME, rd_size, buf);
140	if (! new) {
141		LDNS_FREE(buf);
142		return NULL;
143	}
144
145	/* If dname ends in a root label, the reverse should too.
146	 */
147	if (ldns_dname_last_label_is_root_label(dname)) {
148		buf[rd_size - 1] = 0;
149		rd_size -= 1;
150	}
151	for (src_pos = 0; src_pos < rd_size; src_pos += len + 1) {
152		len = ldns_rdf_data(dname)[src_pos];
153		memcpy(&buf[rd_size - src_pos - len - 1],
154				&ldns_rdf_data(dname)[src_pos], len + 1);
155	}
156	return new;
157}
158
159ldns_rdf *
160ldns_dname_clone_from(const ldns_rdf *d, uint16_t n)
161{
162	uint8_t *data;
163	uint8_t label_size;
164	size_t data_size;
165
166	if (!d ||
167	    ldns_rdf_get_type(d) != LDNS_RDF_TYPE_DNAME ||
168	    ldns_dname_label_count(d) < n) {
169		return NULL;
170	}
171
172	data = ldns_rdf_data(d);
173	data_size = ldns_rdf_size(d);
174	while (n > 0) {
175		label_size = data[0] + 1;
176		data += label_size;
177		if (data_size < label_size) {
178			/* this label is very broken */
179			return NULL;
180		}
181		data_size -= label_size;
182		n--;
183	}
184
185	return ldns_dname_new_frm_data(data_size, data);
186}
187
188ldns_rdf *
189ldns_dname_left_chop(const ldns_rdf *d)
190{
191	uint8_t label_pos;
192	ldns_rdf *chop;
193
194	if (!d) {
195		return NULL;
196	}
197
198	if (ldns_rdf_get_type(d) != LDNS_RDF_TYPE_DNAME) {
199		return NULL;
200	}
201	if (ldns_dname_label_count(d) == 0) {
202		/* root label */
203		return NULL;
204	}
205	/* 05blaat02nl00 */
206	label_pos = ldns_rdf_data(d)[0];
207
208	chop = ldns_dname_new_frm_data(ldns_rdf_size(d) - label_pos - 1,
209			ldns_rdf_data(d) + label_pos + 1);
210	return chop;
211}
212
213uint8_t
214ldns_dname_label_count(const ldns_rdf *r)
215{
216        uint16_t src_pos;
217        uint16_t len;
218        uint8_t i;
219        size_t r_size;
220
221	if (!r) {
222		return 0;
223	}
224
225	i = 0;
226	src_pos = 0;
227	r_size = ldns_rdf_size(r);
228
229	if (ldns_rdf_get_type(r) != LDNS_RDF_TYPE_DNAME) {
230		return 0;
231	} else {
232		len = ldns_rdf_data(r)[src_pos]; /* start of the label */
233
234		/* single root label */
235		if (1 == r_size) {
236			return 0;
237		} else {
238			while ((len > 0) && src_pos < r_size) {
239				src_pos++;
240				src_pos += len;
241				len = ldns_rdf_data(r)[src_pos];
242				i++;
243			}
244		}
245	}
246	return i;
247}
248
249ldns_rdf *
250ldns_dname_new(uint16_t s, void *d)
251{
252        ldns_rdf *rd;
253
254        rd = LDNS_MALLOC(ldns_rdf);
255        if (!rd) {
256                return NULL;
257        }
258        ldns_rdf_set_size(rd, s);
259        ldns_rdf_set_type(rd, LDNS_RDF_TYPE_DNAME);
260        ldns_rdf_set_data(rd, d);
261        return rd;
262}
263
264ldns_rdf *
265ldns_dname_new_frm_str(const char *str)
266{
267	return ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, str);
268}
269
270ldns_rdf *
271ldns_dname_new_frm_data(uint16_t size, const void *data)
272{
273	return ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, size, data);
274}
275
276void
277ldns_dname2canonical(const ldns_rdf *rd)
278{
279	uint8_t *rdd;
280	uint16_t i;
281
282	if (ldns_rdf_get_type(rd) != LDNS_RDF_TYPE_DNAME) {
283		return;
284	}
285
286	rdd = (uint8_t*)ldns_rdf_data(rd);
287	for (i = 0; i < ldns_rdf_size(rd); i++, rdd++) {
288		*rdd = (uint8_t)LDNS_DNAME_NORMALIZE((int)*rdd);
289	}
290}
291
292bool
293ldns_dname_is_subdomain(const ldns_rdf *sub, const ldns_rdf *parent)
294{
295	uint8_t sub_lab;
296	uint8_t par_lab;
297	int8_t i, j;
298	ldns_rdf *tmp_sub = NULL;
299	ldns_rdf *tmp_par = NULL;
300    ldns_rdf *sub_clone;
301    ldns_rdf *parent_clone;
302    bool result = true;
303
304	if (ldns_rdf_get_type(sub) != LDNS_RDF_TYPE_DNAME ||
305			ldns_rdf_get_type(parent) != LDNS_RDF_TYPE_DNAME ||
306			ldns_rdf_compare(sub, parent) == 0) {
307		return false;
308	}
309
310    /* would be nicer if we do not have to clone... */
311    sub_clone = ldns_dname_clone_from(sub, 0);
312    parent_clone = ldns_dname_clone_from(parent, 0);
313    ldns_dname2canonical(sub_clone);
314    ldns_dname2canonical(parent_clone);
315
316	sub_lab = ldns_dname_label_count(sub_clone);
317	par_lab = ldns_dname_label_count(parent_clone);
318
319	/* if sub sits above parent, it cannot be a child/sub domain */
320	if (sub_lab < par_lab) {
321		result = false;
322	} else {
323		/* check all labels the from the parent labels, from right to left.
324		 * When they /all/ match we have found a subdomain
325		 */
326		j = sub_lab - 1; /* we count from zero, thank you */
327		for (i = par_lab -1; i >= 0; i--) {
328			tmp_sub = ldns_dname_label(sub_clone, j);
329			tmp_par = ldns_dname_label(parent_clone, i);
330			if (!tmp_sub || !tmp_par) {
331				/* deep free does null check */
332				ldns_rdf_deep_free(tmp_sub);
333				ldns_rdf_deep_free(tmp_par);
334				result = false;
335				break;
336			}
337
338			if (ldns_rdf_compare(tmp_sub, tmp_par) != 0) {
339				/* they are not equal */
340				ldns_rdf_deep_free(tmp_sub);
341				ldns_rdf_deep_free(tmp_par);
342				result = false;
343				break;
344			}
345			ldns_rdf_deep_free(tmp_sub);
346			ldns_rdf_deep_free(tmp_par);
347			j--;
348		}
349	}
350	ldns_rdf_deep_free(sub_clone);
351	ldns_rdf_deep_free(parent_clone);
352	return result;
353}
354
355int
356ldns_dname_compare(const ldns_rdf *dname1, const ldns_rdf *dname2)
357{
358	size_t lc1, lc2, lc1f, lc2f;
359	size_t i;
360	int result = 0;
361	uint8_t *lp1, *lp2;
362
363	/* see RFC4034 for this algorithm */
364	/* this algorithm assumes the names are normalized to case */
365
366        /* only when both are not NULL we can say anything about them */
367        if (!dname1 && !dname2) {
368                return 0;
369        }
370        if (!dname1 || !dname2) {
371                return -1;
372        }
373	/* asserts must happen later as we are looking in the
374	 * dname, which could be NULL. But this case is handled
375	 * above
376	 */
377	assert(ldns_rdf_get_type(dname1) == LDNS_RDF_TYPE_DNAME);
378	assert(ldns_rdf_get_type(dname2) == LDNS_RDF_TYPE_DNAME);
379
380	lc1 = ldns_dname_label_count(dname1);
381	lc2 = ldns_dname_label_count(dname2);
382
383	if (lc1 == 0 && lc2 == 0) {
384		return 0;
385	}
386	if (lc1 == 0) {
387		return -1;
388	}
389	if (lc2 == 0) {
390		return 1;
391	}
392	lc1--;
393	lc2--;
394	/* we start at the last label */
395	while (true) {
396		/* find the label first */
397		lc1f = lc1;
398		lp1 = ldns_rdf_data(dname1);
399		while (lc1f > 0) {
400			lp1 += *lp1 + 1;
401			lc1f--;
402		}
403
404		/* and find the other one */
405		lc2f = lc2;
406		lp2 = ldns_rdf_data(dname2);
407		while (lc2f > 0) {
408			lp2 += *lp2 + 1;
409			lc2f--;
410		}
411
412		/* now check the label character for character. */
413		for (i = 1; i < (size_t)(*lp1 + 1); i++) {
414			if (i > *lp2) {
415				/* apparently label 1 is larger */
416				result = 1;
417				goto done;
418			}
419			if (LDNS_DNAME_NORMALIZE((int) *(lp1 + i)) <
420			    LDNS_DNAME_NORMALIZE((int) *(lp2 + i))) {
421			    result = -1;
422			    goto done;
423			} else if (LDNS_DNAME_NORMALIZE((int) *(lp1 + i)) >
424			    LDNS_DNAME_NORMALIZE((int) *(lp2 + i))) {
425			    result = 1;
426			    goto done;
427			}
428		}
429		if (*lp1 < *lp2) {
430			/* apparently label 2 is larger */
431			result = -1;
432			goto done;
433		}
434		if (lc1 == 0 && lc2 > 0) {
435			result = -1;
436			goto done;
437		} else if (lc1 > 0 && lc2 == 0) {
438			result = 1;
439			goto done;
440		} else if (lc1 == 0 && lc2 == 0) {
441			result = 0;
442			goto done;
443		}
444		lc1--;
445		lc2--;
446	}
447
448	done:
449	return result;
450}
451
452int
453ldns_dname_is_wildcard(const ldns_rdf* dname)
454{
455	return ( ldns_dname_label_count(dname) > 0 &&
456		 ldns_rdf_data(dname)[0] == 1 &&
457		 ldns_rdf_data(dname)[1] == '*');
458}
459
460int
461ldns_dname_match_wildcard(const ldns_rdf *dname, const ldns_rdf *wildcard)
462{
463	ldns_rdf *wc_chopped;
464	int result;
465	/* check whether it really is a wildcard */
466	if (ldns_dname_is_wildcard(wildcard)) {
467		/* ok, so the dname needs to be a subdomain of the wildcard
468		 * without the *
469		 */
470		wc_chopped = ldns_dname_left_chop(wildcard);
471		result = (int) ldns_dname_is_subdomain(dname, wc_chopped);
472		ldns_rdf_deep_free(wc_chopped);
473	} else {
474		result = (ldns_dname_compare(dname, wildcard) == 0);
475	}
476	return result;
477}
478
479/* nsec test: does prev <= middle < next
480 * -1 = yes
481 * 0 = error/can't tell
482 * 1 = no
483 */
484int
485ldns_dname_interval(const ldns_rdf *prev, const ldns_rdf *middle,
486		const ldns_rdf *next)
487{
488	int prev_check, next_check;
489
490	assert(ldns_rdf_get_type(prev) == LDNS_RDF_TYPE_DNAME);
491	assert(ldns_rdf_get_type(middle) == LDNS_RDF_TYPE_DNAME);
492	assert(ldns_rdf_get_type(next) == LDNS_RDF_TYPE_DNAME);
493
494	prev_check = ldns_dname_compare(prev, middle);
495	next_check = ldns_dname_compare(middle, next);
496	/* <= next. This cannot be the case for nsec, because then we would
497	 * have gotten the nsec of next...
498	 */
499	if (next_check == 0) {
500		return 0;
501	}
502
503			/* <= */
504	if ((prev_check == -1 || prev_check == 0) &&
505			/* < */
506			next_check == -1) {
507		return -1;
508	} else {
509		return 1;
510	}
511}
512
513
514bool
515ldns_dname_str_absolute(const char *dname_str)
516{
517        const char* s;
518	if(dname_str && strcmp(dname_str, ".") == 0)
519		return 1;
520        if(!dname_str || strlen(dname_str) < 2)
521                return 0;
522        if(dname_str[strlen(dname_str) - 1] != '.')
523                return 0;
524        if(dname_str[strlen(dname_str) - 2] != '\\')
525                return 1; /* ends in . and no \ before it */
526        /* so we have the case of ends in . and there is \ before it */
527        for(s=dname_str; *s; s++) {
528                if(*s == '\\') {
529                        if(s[1] && s[2] && s[3] /* check length */
530                                && isdigit(s[1]) && isdigit(s[2]) &&
531                                isdigit(s[3]))
532                                s += 3;
533                        else if(!s[1] || isdigit(s[1])) /* escape of nul,0-9 */
534                                return 0; /* parse error */
535                        else s++; /* another character escaped */
536                }
537                else if(!*(s+1) && *s == '.')
538                        return 1; /* trailing dot, unescaped */
539        }
540        return 0;
541}
542
543bool
544ldns_dname_absolute(const ldns_rdf *rdf)
545{
546	char *str = ldns_rdf2str(rdf);
547	if (str) {
548		bool r = ldns_dname_str_absolute(str);
549		LDNS_FREE(str);
550		return r;
551	}
552	return false;
553}
554
555ldns_rdf *
556ldns_dname_label(const ldns_rdf *rdf, uint8_t labelpos)
557{
558	uint8_t labelcnt;
559	uint16_t src_pos;
560	uint16_t len;
561	ldns_rdf *tmpnew;
562	size_t s;
563	uint8_t *data;
564
565	if (ldns_rdf_get_type(rdf) != LDNS_RDF_TYPE_DNAME) {
566		return NULL;
567	}
568
569	labelcnt = 0;
570	src_pos = 0;
571	s = ldns_rdf_size(rdf);
572
573	len = ldns_rdf_data(rdf)[src_pos]; /* label start */
574	while ((len > 0) && src_pos < s) {
575		if (labelcnt == labelpos) {
576			/* found our label */
577			data = LDNS_XMALLOC(uint8_t, len + 2);
578			if (!data) {
579				return NULL;
580			}
581			memcpy(data, ldns_rdf_data(rdf) + src_pos, len + 1);
582			data[len + 2 - 1] = 0;
583
584			tmpnew = ldns_rdf_new( LDNS_RDF_TYPE_DNAME
585					     , len + 2, data);
586			if (!tmpnew) {
587				LDNS_FREE(data);
588				return NULL;
589			}
590			return tmpnew;
591		}
592		src_pos++;
593		src_pos += len;
594		len = ldns_rdf_data(rdf)[src_pos];
595		labelcnt++;
596	}
597	return NULL;
598}
599