1 /* 2 * util/data/dname.h - domain name routines 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains functions to deal with domain names (dnames). 40 * 41 * Some of the functions deal with domain names as a wireformat buffer, 42 * with a length. 43 */ 44 45 #ifndef UTIL_DATA_DNAME_H 46 #define UTIL_DATA_DNAME_H 47 #include "util/storage/lruhash.h" 48 49 /** max number of compression ptrs to follow */ 50 #define MAX_COMPRESS_PTRS 256 51 52 /** 53 * Determine length of dname in buffer, no compression ptrs allowed, 54 * @param query: the ldns buffer, current position at start of dname. 55 * at end, position is at end of the dname. 56 * @return: 0 on parse failure, or length including ending 0 of dname. 57 */ 58 size_t query_dname_len(ldns_buffer* query); 59 60 /** 61 * Determine if dname in memory is correct. no compression ptrs allowed. 62 * @param dname: where dname starts in memory. 63 * @param len: dname is not allowed to exceed this length (i.e. of allocation). 64 * @return length of dname if dname is ok, 0 on a parse error. 65 */ 66 size_t dname_valid(uint8_t* dname, size_t len); 67 68 /** lowercase query dname */ 69 void query_dname_tolower(uint8_t* dname); 70 71 /** 72 * lowercase pkt dname (follows compression pointers) 73 * @param pkt: the packet, used to follow compression pointers. Position 74 * is unchanged. 75 * @param dname: start of dname in packet. 76 */ 77 void pkt_dname_tolower(ldns_buffer* pkt, uint8_t* dname); 78 79 /** 80 * Compare query dnames (uncompressed storage). The Dnames passed do not 81 * have to be lowercased, comparison routine does this. 82 * 83 * This routine is special, in that the comparison that it does corresponds 84 * with the canonical comparison needed when comparing dnames inside rdata 85 * for RR types that need canonicalization. That means that the first byte 86 * that is smaller (possibly after lowercasing) makes an RR smaller, or the 87 * shortest name makes an RR smaller. 88 * 89 * This routine does not compute the canonical order needed for NSEC 90 * processing. 91 * 92 * Dnames have to be valid format. 93 * @param d1: dname to compare 94 * @param d2: dname to compare 95 * @return: -1, 0, or +1 depending on comparison results. 96 * Sort order is first difference found. not the canonical ordering. 97 */ 98 int query_dname_compare(uint8_t* d1, uint8_t* d2); 99 100 /** 101 * Determine correct, compressed, dname present in packet. 102 * Checks for parse errors. 103 * @param pkt: packet to read from (from current start position). 104 * @return: 0 on parse error. 105 * At exit the position is right after the (compressed) dname. 106 * Compression pointers are followed and checked for loops. 107 * The uncompressed wireformat length is returned. 108 */ 109 size_t pkt_dname_len(ldns_buffer* pkt); 110 111 /** 112 * Compare dnames in packet (compressed). Dnames must be valid. 113 * routine performs lowercasing, so the packet casing is preserved. 114 * @param pkt: packet, used to resolve compression pointers. 115 * @param d1: dname to compare 116 * @param d2: dname to compare 117 * @return: -1, 0, or +1 depending on comparison results. 118 * Sort order is first difference found. not the canonical ordering. 119 */ 120 int dname_pkt_compare(ldns_buffer* pkt, uint8_t* d1, uint8_t* d2); 121 122 /** 123 * Hash dname, label by label, lowercasing, into hashvalue. 124 * Dname in query format (not compressed). 125 * @param dname: dname to hash. 126 * @param h: initial hash value. 127 * @return: result hash value. 128 */ 129 hashvalue_t dname_query_hash(uint8_t* dname, hashvalue_t h); 130 131 /** 132 * Hash dname, label by label, lowercasing, into hashvalue. 133 * Dname in pkt format (compressed). 134 * @param pkt: packet, for resolving compression pointers. 135 * @param dname: dname to hash, pointer to the pkt buffer. 136 * Must be valid format. No loops, etc. 137 * @param h: initial hash value. 138 * @return: result hash value. 139 * Result is the same as dname_query_hash, even if compression is used. 140 */ 141 hashvalue_t dname_pkt_hash(ldns_buffer* pkt, uint8_t* dname, hashvalue_t h); 142 143 /** 144 * Copy over a valid dname and decompress it. 145 * @param pkt: packet to resolve compression pointers. 146 * @param to: buffer of size from pkt_len function to hold result. 147 * @param dname: pointer into packet where dname starts. 148 */ 149 void dname_pkt_copy(ldns_buffer* pkt, uint8_t* to, uint8_t* dname); 150 151 /** 152 * Copy over a valid dname to a packet. 153 * @param pkt: packet to copy to. 154 * @param dname: dname to copy. 155 * @return: 0 if not enough space in buffer. 156 */ 157 int dname_buffer_write(ldns_buffer* pkt, uint8_t* dname); 158 159 /** 160 * Count the number of labels in an uncompressed dname in memory. 161 * @param dname: pointer to uncompressed dname. 162 * @return: count of labels, including root label, "com." has 2 labels. 163 */ 164 int dname_count_labels(uint8_t* dname); 165 166 /** 167 * Count labels and dname length both, for uncompressed dname in memory. 168 * @param dname: pointer to uncompressed dname. 169 * @param size: length of dname, including root label. 170 * @return: count of labels, including root label, "com." has 2 labels. 171 */ 172 int dname_count_size_labels(uint8_t* dname, size_t* size); 173 174 /** 175 * Compare dnames, sorted not canonical, but by label. 176 * Such that zone contents follows zone apex. 177 * @param d1: first dname. pointer to uncompressed wireformat. 178 * @param labs1: number of labels in first dname. 179 * @param d2: second dname. pointer to uncompressed wireformat. 180 * @param labs2: number of labels in second dname. 181 * @param mlabs: number of labels that matched exactly (the shared topdomain). 182 * @return: 0 for equal, -1 smaller, or +1 d1 larger than d2. 183 */ 184 int dname_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, int* mlabs); 185 186 /** 187 * See if domain name d1 is a strict subdomain of d2. 188 * That is a subdomain, but not equal. 189 * @param d1: domain name, uncompressed wireformat 190 * @param labs1: number of labels in d1, including root label. 191 * @param d2: domain name, uncompressed wireformat 192 * @param labs2: number of labels in d2, including root label. 193 * @return true if d1 is a subdomain of d2, but not equal to d2. 194 */ 195 int dname_strict_subdomain(uint8_t* d1, int labs1, uint8_t* d2, int labs2); 196 197 /** 198 * Like dname_strict_subdomain but counts labels 199 * @param d1: domain name, uncompressed wireformat 200 * @param d2: domain name, uncompressed wireformat 201 * @return true if d1 is a subdomain of d2, but not equal to d2. 202 */ 203 int dname_strict_subdomain_c(uint8_t* d1, uint8_t* d2); 204 205 /** 206 * Counts labels. Tests is d1 is a subdomain of d2. 207 * @param d1: domain name, uncompressed wireformat 208 * @param d2: domain name, uncompressed wireformat 209 * @return true if d1 is a subdomain of d2. 210 */ 211 int dname_subdomain_c(uint8_t* d1, uint8_t* d2); 212 213 /** 214 * Debug helper. Print wireformat dname to output. 215 * @param out: like stdout or a file. 216 * @param pkt: if not NULL, the packet for resolving compression ptrs. 217 * @param dname: pointer to (start of) dname. 218 */ 219 void dname_print(FILE* out, ldns_buffer* pkt, uint8_t* dname); 220 221 /** 222 * Debug helper. Print dname to given string buffer (string buffer must 223 * be at least 255 chars + 1 for the 0, in printable form. 224 * This may lose information (? for nonprintable characters, or & if 225 * the name is too long, # for a bad label length). 226 * @param dname: uncompressed wireformat. 227 * @param str: buffer of 255+1 length. 228 */ 229 void dname_str(uint8_t* dname, char* str); 230 231 /** 232 * Returns true if the uncompressed wireformat dname is the root "." 233 * @param dname: the dname to check 234 * @return true if ".", false if not. 235 */ 236 int dname_is_root(uint8_t* dname); 237 238 /** 239 * Snip off first label from a dname, returning the parent zone. 240 * @param dname: from what to strip off. uncompressed wireformat. 241 * @param len: length, adjusted to become less. 242 * @return stripped off, or "." if input was ".". 243 */ 244 void dname_remove_label(uint8_t** dname, size_t* len); 245 246 /** 247 * Snip off first N labels from a dname, returning the parent zone. 248 * @param dname: from what to strip off. uncompressed wireformat. 249 * @param len: length, adjusted to become less. 250 * @param n: number of labels to strip off (from the left). 251 * if 0, nothing happens. 252 * @return stripped off, or "." if input was ".". 253 */ 254 void dname_remove_labels(uint8_t** dname, size_t* len, int n); 255 256 /** 257 * Count labels for the RRSIG signature label field. 258 * Like a normal labelcount, but "*" wildcard and "." root are not counted. 259 * @param dname: valid uncompressed wireformat. 260 * @return number of labels like in RRSIG; '*' and '.' are not counted. 261 */ 262 int dname_signame_label_count(uint8_t* dname); 263 264 /** 265 * Return true if the label is a wildcard, *.example.com. 266 * @param dname: valid uncompressed wireformat. 267 * @return true if wildcard, or false. 268 */ 269 int dname_is_wild(uint8_t* dname); 270 271 /** 272 * Compare dnames, Canonical in rfc4034 sense, but by label. 273 * Such that zone contents follows zone apex. 274 * 275 * @param d1: first dname. pointer to uncompressed wireformat. 276 * @param labs1: number of labels in first dname. 277 * @param d2: second dname. pointer to uncompressed wireformat. 278 * @param labs2: number of labels in second dname. 279 * @param mlabs: number of labels that matched exactly (the shared topdomain). 280 * @return: 0 for equal, -1 smaller, or +1 d1 larger than d2. 281 */ 282 int dname_canon_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, 283 int* mlabs); 284 285 /** 286 * Canonical dname compare. Takes care of counting labels. 287 * Per rfc 4034 canonical order. 288 * 289 * @param d1: first dname. pointer to uncompressed wireformat. 290 * @param d2: second dname. pointer to uncompressed wireformat. 291 * @return: 0 for equal, -1 smaller, or +1 d1 larger than d2. 292 */ 293 int dname_canonical_compare(uint8_t* d1, uint8_t* d2); 294 295 /** 296 * Get the shared topdomain between two names. Root "." or longer. 297 * @param d1: first dname. pointer to uncompressed wireformat. 298 * @param d2: second dname. pointer to uncompressed wireformat. 299 * @return pointer to shared topdomain. Ptr to a part of d1. 300 */ 301 uint8_t* dname_get_shared_topdomain(uint8_t* d1, uint8_t* d2); 302 303 #endif /* UTIL_DATA_DNAME_H */ 304