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 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE 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 struct sldns_buffer; 49 50 /** max number of compression ptrs to follow */ 51 #define MAX_COMPRESS_PTRS 256 52 53 /** 54 * Determine length of dname in buffer, no compression ptrs allowed, 55 * @param query: the ldns buffer, current position at start of dname. 56 * at end, position is at end of the dname. 57 * @return: 0 on parse failure, or length including ending 0 of dname. 58 */ 59 size_t query_dname_len(struct sldns_buffer* query); 60 61 /** 62 * Determine if dname in memory is correct. no compression ptrs allowed. 63 * @param dname: where dname starts in memory. 64 * @param len: dname is not allowed to exceed this length (i.e. of allocation). 65 * @return length of dname if dname is ok, 0 on a parse error. 66 */ 67 size_t dname_valid(uint8_t* dname, size_t len); 68 69 /** lowercase query dname */ 70 void query_dname_tolower(uint8_t* dname); 71 72 /** 73 * lowercase pkt dname (follows compression pointers) 74 * @param pkt: the packet, used to follow compression pointers. Position 75 * is unchanged. 76 * @param dname: start of dname in packet. 77 */ 78 void pkt_dname_tolower(struct sldns_buffer* pkt, uint8_t* dname); 79 80 /** 81 * Compare query dnames (uncompressed storage). The Dnames passed do not 82 * have to be lowercased, comparison routine does this. 83 * 84 * This routine is special, in that the comparison that it does corresponds 85 * with the canonical comparison needed when comparing dnames inside rdata 86 * for RR types that need canonicalization. That means that the first byte 87 * that is smaller (possibly after lowercasing) makes an RR smaller, or the 88 * shortest name makes an RR smaller. 89 * 90 * This routine does not compute the canonical order needed for NSEC 91 * processing. 92 * 93 * Dnames have to be valid format. 94 * @param d1: dname to compare 95 * @param d2: dname to compare 96 * @return: -1, 0, or +1 depending on comparison results. 97 * Sort order is first difference found. not the canonical ordering. 98 */ 99 int query_dname_compare(uint8_t* d1, uint8_t* d2); 100 101 /** 102 * Determine correct, compressed, dname present in packet. 103 * Checks for parse errors. 104 * @param pkt: packet to read from (from current start position). 105 * @return: 0 on parse error. 106 * At exit the position is right after the (compressed) dname. 107 * Compression pointers are followed and checked for loops. 108 * The uncompressed wireformat length is returned. 109 */ 110 size_t pkt_dname_len(struct sldns_buffer* pkt); 111 112 /** 113 * Compare dnames in packet (compressed). Dnames must be valid. 114 * routine performs lowercasing, so the packet casing is preserved. 115 * @param pkt: packet, used to resolve compression pointers. 116 * @param d1: dname to compare 117 * @param d2: dname to compare 118 * @return: -1, 0, or +1 depending on comparison results. 119 * Sort order is first difference found. not the canonical ordering. 120 */ 121 int dname_pkt_compare(struct sldns_buffer* pkt, uint8_t* d1, uint8_t* d2); 122 123 /** 124 * Hash dname, label by label, lowercasing, into hashvalue. 125 * Dname in query format (not compressed). 126 * @param dname: dname to hash. 127 * @param h: initial hash value. 128 * @return: result hash value. 129 */ 130 hashvalue_t dname_query_hash(uint8_t* dname, hashvalue_t h); 131 132 /** 133 * Hash dname, label by label, lowercasing, into hashvalue. 134 * Dname in pkt format (compressed). 135 * @param pkt: packet, for resolving compression pointers. 136 * @param dname: dname to hash, pointer to the pkt buffer. 137 * Must be valid format. No loops, etc. 138 * @param h: initial hash value. 139 * @return: result hash value. 140 * Result is the same as dname_query_hash, even if compression is used. 141 */ 142 hashvalue_t dname_pkt_hash(struct sldns_buffer* pkt, uint8_t* dname, hashvalue_t h); 143 144 /** 145 * Copy over a valid dname and decompress it. 146 * @param pkt: packet to resolve compression pointers. 147 * @param to: buffer of size from pkt_len function to hold result. 148 * @param dname: pointer into packet where dname starts. 149 */ 150 void dname_pkt_copy(struct sldns_buffer* pkt, uint8_t* to, uint8_t* dname); 151 152 /** 153 * Copy over a valid dname to a packet. 154 * @param pkt: packet to copy to. 155 * @param dname: dname to copy. 156 * @return: 0 if not enough space in buffer. 157 */ 158 int dname_buffer_write(struct sldns_buffer* pkt, uint8_t* dname); 159 160 /** 161 * Count the number of labels in an uncompressed dname in memory. 162 * @param dname: pointer to uncompressed dname. 163 * @return: count of labels, including root label, "com." has 2 labels. 164 */ 165 int dname_count_labels(uint8_t* dname); 166 167 /** 168 * Count labels and dname length both, for uncompressed dname in memory. 169 * @param dname: pointer to uncompressed dname. 170 * @param size: length of dname, including root label. 171 * @return: count of labels, including root label, "com." has 2 labels. 172 */ 173 int dname_count_size_labels(uint8_t* dname, size_t* size); 174 175 /** 176 * Compare dnames, sorted not canonical, but by label. 177 * Such that zone contents follows zone apex. 178 * @param d1: first dname. pointer to uncompressed wireformat. 179 * @param labs1: number of labels in first dname. 180 * @param d2: second dname. pointer to uncompressed wireformat. 181 * @param labs2: number of labels in second dname. 182 * @param mlabs: number of labels that matched exactly (the shared topdomain). 183 * @return: 0 for equal, -1 smaller, or +1 d1 larger than d2. 184 */ 185 int dname_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, int* mlabs); 186 187 /** 188 * See if domain name d1 is a strict subdomain of d2. 189 * That is a subdomain, but not equal. 190 * @param d1: domain name, uncompressed wireformat 191 * @param labs1: number of labels in d1, including root label. 192 * @param d2: domain name, uncompressed wireformat 193 * @param labs2: number of labels in d2, including root label. 194 * @return true if d1 is a subdomain of d2, but not equal to d2. 195 */ 196 int dname_strict_subdomain(uint8_t* d1, int labs1, uint8_t* d2, int labs2); 197 198 /** 199 * Like dname_strict_subdomain but counts labels 200 * @param d1: domain name, uncompressed wireformat 201 * @param d2: domain name, uncompressed wireformat 202 * @return true if d1 is a subdomain of d2, but not equal to d2. 203 */ 204 int dname_strict_subdomain_c(uint8_t* d1, uint8_t* d2); 205 206 /** 207 * Counts labels. Tests is d1 is a subdomain of d2. 208 * @param d1: domain name, uncompressed wireformat 209 * @param d2: domain name, uncompressed wireformat 210 * @return true if d1 is a subdomain of d2. 211 */ 212 int dname_subdomain_c(uint8_t* d1, uint8_t* d2); 213 214 /** 215 * Debug helper. Print wireformat dname to output. 216 * @param out: like stdout or a file. 217 * @param pkt: if not NULL, the packet for resolving compression ptrs. 218 * @param dname: pointer to (start of) dname. 219 */ 220 void dname_print(FILE* out, struct sldns_buffer* pkt, uint8_t* dname); 221 222 /** 223 * Debug helper. Print dname to given string buffer (string buffer must 224 * be at least 255 chars + 1 for the 0, in printable form. 225 * This may lose information (? for nonprintable characters, or & if 226 * the name is too long, # for a bad label length). 227 * @param dname: uncompressed wireformat. 228 * @param str: buffer of 255+1 length. 229 */ 230 void dname_str(uint8_t* dname, char* str); 231 232 /** 233 * Returns true if the uncompressed wireformat dname is the root "." 234 * @param dname: the dname to check 235 * @return true if ".", false if not. 236 */ 237 int dname_is_root(uint8_t* dname); 238 239 /** 240 * Snip off first label from a dname, returning the parent zone. 241 * @param dname: from what to strip off. uncompressed wireformat. 242 * @param len: length, adjusted to become less. 243 * @return stripped off, or "." if input was ".". 244 */ 245 void dname_remove_label(uint8_t** dname, size_t* len); 246 247 /** 248 * Snip off first N labels from a dname, returning the parent zone. 249 * @param dname: from what to strip off. uncompressed wireformat. 250 * @param len: length, adjusted to become less. 251 * @param n: number of labels to strip off (from the left). 252 * if 0, nothing happens. 253 * @return stripped off, or "." if input was ".". 254 */ 255 void dname_remove_labels(uint8_t** dname, size_t* len, int n); 256 257 /** 258 * Count labels for the RRSIG signature label field. 259 * Like a normal labelcount, but "*" wildcard and "." root are not counted. 260 * @param dname: valid uncompressed wireformat. 261 * @return number of labels like in RRSIG; '*' and '.' are not counted. 262 */ 263 int dname_signame_label_count(uint8_t* dname); 264 265 /** 266 * Return true if the label is a wildcard, *.example.com. 267 * @param dname: valid uncompressed wireformat. 268 * @return true if wildcard, or false. 269 */ 270 int dname_is_wild(uint8_t* dname); 271 272 /** 273 * Compare dnames, Canonical in rfc4034 sense, but by label. 274 * Such that zone contents follows zone apex. 275 * 276 * @param d1: first dname. pointer to uncompressed wireformat. 277 * @param labs1: number of labels in first dname. 278 * @param d2: second dname. pointer to uncompressed wireformat. 279 * @param labs2: number of labels in second dname. 280 * @param mlabs: number of labels that matched exactly (the shared topdomain). 281 * @return: 0 for equal, -1 smaller, or +1 d1 larger than d2. 282 */ 283 int dname_canon_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, 284 int* mlabs); 285 286 /** 287 * Canonical dname compare. Takes care of counting labels. 288 * Per rfc 4034 canonical order. 289 * 290 * @param d1: first dname. pointer to uncompressed wireformat. 291 * @param d2: second dname. pointer to uncompressed wireformat. 292 * @return: 0 for equal, -1 smaller, or +1 d1 larger than d2. 293 */ 294 int dname_canonical_compare(uint8_t* d1, uint8_t* d2); 295 296 /** 297 * Get the shared topdomain between two names. Root "." or longer. 298 * @param d1: first dname. pointer to uncompressed wireformat. 299 * @param d2: second dname. pointer to uncompressed wireformat. 300 * @return pointer to shared topdomain. Ptr to a part of d1. 301 */ 302 uint8_t* dname_get_shared_topdomain(uint8_t* d1, uint8_t* d2); 303 304 #endif /* UTIL_DATA_DNAME_H */ 305