jjako | a7cd249 | 2003-04-11 09:40:12 +0000 | [diff] [blame] | 1 | /* |
| 2 | * IP address pool functions. |
| 3 | * Copyright (C) 2003 Mondru AB. |
| 4 | * |
| 5 | * The contents of this file may be used under the terms of the GNU |
| 6 | * General Public License Version 2, provided that the above copyright |
| 7 | * notice and this permission notice is included in all copies or |
| 8 | * substantial portions of the software. |
| 9 | * |
| 10 | * The initial developer of the original code is |
| 11 | * Jens Jakobsen <jj@openggsn.org> |
| 12 | * |
| 13 | * Contributor(s): |
| 14 | * |
| 15 | */ |
| 16 | |
| 17 | #include <netinet/in.h> /* in_addr */ |
| 18 | #include <stdlib.h> /* calloc */ |
| 19 | #include <stdio.h> /* sscanf */ |
| 20 | |
| 21 | #include "ippool.h" |
| 22 | |
| 23 | |
| 24 | /* |
| 25 | -------------------------------------------------------------------- |
| 26 | Public domain by From Bob Jenkins, December 1996. |
| 27 | mix -- mix 3 32-bit values reversibly. |
| 28 | For every delta with one or two bit set, and the deltas of all three |
| 29 | high bits or all three low bits, whether the original value of a,b,c |
| 30 | is almost all zero or is uniformly distributed, |
| 31 | * If mix() is run forward or backward, at least 32 bits in a,b,c |
| 32 | have at least 1/4 probability of changing. |
| 33 | * If mix() is run forward, every bit of c will change between 1/3 and |
| 34 | 2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.) |
| 35 | mix() was built out of 36 single-cycle latency instructions in a |
| 36 | structure that could supported 2x parallelism, like so: |
| 37 | a -= b; |
| 38 | a -= c; x = (c>>13); |
| 39 | b -= c; a ^= x; |
| 40 | b -= a; x = (a<<8); |
| 41 | c -= a; b ^= x; |
| 42 | c -= b; x = (b>>13); |
| 43 | ... |
| 44 | Unfortunately, superscalar Pentiums and Sparcs can't take advantage |
| 45 | of that parallelism. They've also turned some of those single-cycle |
| 46 | latency instructions into multi-cycle latency instructions. Still, |
| 47 | this is the fastest good hash I could find. There were about 2^^68 |
| 48 | to choose from. I only looked at a billion or so. |
| 49 | -------------------------------------------------------------------- |
| 50 | */ |
| 51 | #define mix(a,b,c) \ |
| 52 | { \ |
| 53 | a -= b; a -= c; a ^= (c>>13); \ |
| 54 | b -= c; b -= a; b ^= (a<<8); \ |
| 55 | c -= a; c -= b; c ^= (b>>13); \ |
| 56 | a -= b; a -= c; a ^= (c>>12); \ |
| 57 | b -= c; b -= a; b ^= (a<<16); \ |
| 58 | c -= a; c -= b; c ^= (b>>5); \ |
| 59 | a -= b; a -= c; a ^= (c>>3); \ |
| 60 | b -= c; b -= a; b ^= (a<<10); \ |
| 61 | c -= a; c -= b; c ^= (b>>15); \ |
| 62 | } |
| 63 | /* |
| 64 | -------------------------------------------------------------------- |
| 65 | lookup() -- hash a variable-length key into a 32-bit value |
| 66 | k : the key (the unaligned variable-length array of bytes) |
| 67 | len : the length of the key, counting by bytes |
| 68 | level : can be any 4-byte value |
| 69 | Returns a 32-bit value. Every bit of the key affects every bit of |
| 70 | the return value. Every 1-bit and 2-bit delta achieves avalanche. |
| 71 | About 6len+35 instructions. |
| 72 | |
| 73 | The best hash table sizes are powers of 2. There is no need to do |
| 74 | mod a prime (mod is sooo slow!). If you need less than 32 bits, |
| 75 | use a bitmask. For example, if you need only 10 bits, do |
| 76 | h = (h & hashmask(10)); |
| 77 | In which case, the hash table should have hashsize(10) elements. |
| 78 | |
| 79 | If you are hashing n strings (ub1 **)k, do it like this: |
| 80 | for (i=0, h=0; i<n; ++i) h = lookup( k[i], len[i], h); |
| 81 | |
| 82 | By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this |
| 83 | code any way you wish, private, educational, or commercial. |
| 84 | |
| 85 | See http://burtleburtle.net/bob/hash/evahash.html |
| 86 | Use for hash table lookup, or anything where one collision in 2^32 is |
| 87 | acceptable. Do NOT use for cryptographic purposes. |
| 88 | -------------------------------------------------------------------- |
| 89 | */ |
| 90 | |
| 91 | unsigned long int lookup( k, length, level) |
| 92 | register unsigned char *k; /* the key */ |
| 93 | register unsigned long int length; /* the length of the key */ |
| 94 | register unsigned long int level; /* the previous hash, or an arbitrary value */ |
| 95 | { |
| 96 | register unsigned long int a,b,c,len; |
| 97 | |
| 98 | /* Set up the internal state */ |
| 99 | len = length; |
| 100 | a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */ |
| 101 | c = level; /* the previous hash value */ |
| 102 | |
| 103 | /*---------------------------------------- handle most of the key */ |
| 104 | while (len >= 12) |
| 105 | { |
| 106 | a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24)); |
| 107 | b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24)); |
| 108 | c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24)); |
| 109 | mix(a,b,c); |
| 110 | k += 12; len -= 12; |
| 111 | } |
| 112 | |
| 113 | /*------------------------------------- handle the last 11 bytes */ |
| 114 | c += length; |
| 115 | switch(len) /* all the case statements fall through */ |
| 116 | { |
| 117 | case 11: c+=((ub4)k[10]<<24); |
| 118 | case 10: c+=((ub4)k[9]<<16); |
| 119 | case 9 : c+=((ub4)k[8]<<8); |
| 120 | /* the first byte of c is reserved for the length */ |
| 121 | case 8 : b+=((ub4)k[7]<<24); |
| 122 | case 7 : b+=((ub4)k[6]<<16); |
| 123 | case 6 : b+=((ub4)k[5]<<8); |
| 124 | case 5 : b+=k[4]; |
| 125 | case 4 : a+=((ub4)k[3]<<24); |
| 126 | case 3 : a+=((ub4)k[2]<<16); |
| 127 | case 2 : a+=((ub4)k[1]<<8); |
| 128 | case 1 : a+=k[0]; |
| 129 | /* case 0: nothing left to add */ |
| 130 | } |
| 131 | mix(a,b,c); |
| 132 | /*-------------------------------------------- report the result */ |
| 133 | return c; |
| 134 | } |
| 135 | |
| 136 | /* |
| 137 | End of public domain code by From Bob Jenkins, December 1996. |
| 138 | -------------------------------------------------------------------- |
| 139 | */ |
| 140 | |
| 141 | int ippool_printaddr(struct ippool_t *this) { |
| 142 | int n; |
| 143 | printf("ippool_printaddr\n"); |
| 144 | printf("First %d\n", this->first - this->member); |
| 145 | printf("Last %d\n", this->last - this->member); |
| 146 | printf("Listsize %d\n", this->listsize); |
| 147 | |
| 148 | for (n=0; n<this->listsize; n++) { |
| 149 | printf("Unit %d inuse %d prev %d next %d addr %x\n", |
| 150 | n, |
| 151 | this->member[n].inuse, |
| 152 | this->member[n].prev - this->member, |
| 153 | this->member[n].next - this->member, |
| 154 | this->member[n].addr.s_addr |
| 155 | ); |
| 156 | } |
| 157 | return 0; |
| 158 | } |
| 159 | |
| 160 | |
| 161 | unsigned long int ippool_hash4(struct in_addr *addr) { |
| 162 | return lookup(&addr->s_addr, sizeof(addr->s_addr), 0); |
| 163 | } |
| 164 | |
| 165 | #ifndef IPPOOL_NOIP6 |
| 166 | unsigned long int ippool_hash6(struct in6_addr *addr) { |
| 167 | return lookup(addr->u6_addr8, sizeof(addr->u6_addr8), 0); |
| 168 | } |
| 169 | #endif |
| 170 | |
| 171 | |
| 172 | /* Get IP address and mask */ |
| 173 | int ippool_aton(struct in_addr *addr, struct in_addr *mask, |
| 174 | char *pool, int number) { |
| 175 | |
| 176 | /* Parse only first instance of network for now */ |
| 177 | /* Eventually "number" will indicate the token which we want to parse */ |
| 178 | |
| 179 | unsigned int a1, a2, a3, a4; |
| 180 | unsigned int m1, m2, m3, m4; |
| 181 | int c; |
| 182 | unsigned int m; |
| 183 | int masklog; |
| 184 | |
| 185 | c = sscanf(pool, "%u.%u.%u.%u/%u.%u.%u.%u", |
| 186 | &a1, &a2, &a3, &a4, |
| 187 | &m1, &m2, &m3, &m4); |
| 188 | switch (c) { |
| 189 | case 4: |
| 190 | if (a1 == 0 && a2 == 0 && a3 == 0 && a4 == 0) /* Full Internet */ |
| 191 | mask->s_addr = 0x00000000; |
| 192 | else if (a2 == 0 && a3 == 0 && a4 == 0) /* class A */ |
| 193 | mask->s_addr = htonl(0xff000000); |
| 194 | else if (a3 == 0 && a4 == 0) /* class B */ |
| 195 | mask->s_addr = htonl(0xffff0000); |
| 196 | else if (a4 == 0) /* class C */ |
| 197 | mask->s_addr = htonl(0xffffff00); |
| 198 | else |
| 199 | mask->s_addr = 0xffffffff; |
| 200 | break; |
| 201 | case 5: |
| 202 | if (m1 < 0 || m1 > 32) { |
| 203 | return -1; /* Invalid mask */ |
| 204 | } |
| 205 | mask->s_addr = htonl(0xffffffff << (32 - m1)); |
| 206 | break; |
| 207 | case 8: |
| 208 | if (m1 >= 256 || m2 >= 256 || m3 >= 256 || m4 >= 256) |
| 209 | return -1; /* Wrong mask format */ |
| 210 | m = m1 * 0x1000000 + m2 * 0x10000 + m3 * 0x100 + m4; |
| 211 | for (masklog = 0; ((1 << masklog) < ((~m)+1)); masklog++); |
| 212 | if (((~m)+1) != (1 << masklog)) |
| 213 | return -1; /* Wrong mask format (not all ones followed by all zeros)*/ |
| 214 | mask->s_addr = htonl(m); |
| 215 | break; |
| 216 | default: |
| 217 | return -1; /* Invalid mask */ |
| 218 | } |
| 219 | |
| 220 | if (a1 >= 256 || a2 >= 256 || a3 >= 256 || a4 >= 256) |
| 221 | return -1; /* Wrong IP address format */ |
| 222 | else |
| 223 | addr->s_addr = htonl(a1 * 0x1000000 + a2 * 0x10000 + a3 * 0x100 + a4); |
| 224 | |
| 225 | return 0; |
| 226 | } |
| 227 | |
| 228 | /* Create new address pool */ |
| 229 | int ippool_new(struct ippool_t **this, char *pool, int flags) { |
| 230 | |
| 231 | /* Parse only first instance of network for now */ |
| 232 | |
| 233 | int i; |
| 234 | struct ippoolm_t *p; |
| 235 | struct ippoolm_t *p_prev = NULL; |
| 236 | uint32_t hash; |
| 237 | struct in_addr addr; |
| 238 | struct in_addr mask; |
| 239 | unsigned int m; |
| 240 | unsigned int listsize; |
| 241 | |
| 242 | if (ippool_aton(&addr, &mask, pool, 0)) |
| 243 | return 0; /* Failed to parse pool */ |
| 244 | |
| 245 | m = ntohl(mask.s_addr); |
| 246 | listsize = ((~m)+1); |
| 247 | if (flags & IPPOOL_NONETWORK) /* Exclude network address from pool */ |
| 248 | listsize--; |
| 249 | if (flags & IPPOOL_NOBROADCAST) /* Exclude broadcast address from pool */ |
| 250 | listsize--; |
| 251 | |
| 252 | if (!(*this = calloc(sizeof(struct ippool_t), 1))) { |
| 253 | /* Failed to allocate memory for ippool */ |
| 254 | return -1; |
| 255 | } |
| 256 | |
| 257 | (*this)->listsize += listsize; |
| 258 | if (!((*this)->member = calloc(sizeof(struct ippoolm_t), (*this)->listsize))){ |
| 259 | /* Failed to allocate memory for members in ippool */ |
| 260 | return -1; |
| 261 | } |
| 262 | |
| 263 | for ((*this)->hashlog = 0; |
| 264 | ((1 << (*this)->hashlog) < listsize); |
| 265 | (*this)->hashlog++); |
| 266 | |
| 267 | /* printf ("Hashlog %d %d %d\n", (*this)->hashlog, listsize, (1 << (*this)->hashlog)); */ |
| 268 | |
| 269 | /* Determine hashsize */ |
| 270 | (*this)->hashsize = 1 << (*this)->hashlog; /* Fails if mask=0: All Internet*/ |
| 271 | (*this)->hashmask = (*this)->hashsize -1; |
| 272 | |
| 273 | /* Allocate hash table */ |
| 274 | if (!((*this)->hash = calloc(sizeof(struct ippoolm_t), (*this)->hashsize))){ |
| 275 | /* Failed to allocate memory for hash members in ippool */ |
| 276 | return -1; |
| 277 | } |
| 278 | |
| 279 | (*this)->first = NULL; |
| 280 | (*this)->last = NULL; |
| 281 | for (i = 0; i<(*this)->listsize; i++) { |
| 282 | |
| 283 | if (flags & IPPOOL_NONETWORK) |
| 284 | (*this)->member[i].addr.s_addr = htonl(ntohl(addr.s_addr) + i + 1); |
| 285 | else |
| 286 | (*this)->member[i].addr.s_addr = htonl(ntohl(addr.s_addr) + i); |
| 287 | |
| 288 | (*this)->member[i].inuse = 0; |
| 289 | (*this)->member[i].parent = *this; |
| 290 | |
| 291 | /* Insert into list of unused */ |
| 292 | (*this)->member[i].prev = (*this)->last; |
| 293 | if ((*this)->last) { |
| 294 | (*this)->last->next = &((*this)->member[i]); |
| 295 | } |
| 296 | else { |
| 297 | (*this)->first = &((*this)->member[i]); |
| 298 | } |
| 299 | (*this)->last = &((*this)->member[i]); |
| 300 | (*this)->member[i].next = NULL; /* Redundant */ |
| 301 | |
| 302 | /* Insert into hash table */ |
| 303 | hash = ippool_hash4(&(*this)->member[i].addr) & (*this)->hashmask; |
| 304 | for (p = (*this)->hash[hash]; p; p = p->nexthash) |
| 305 | p_prev = p; |
| 306 | if (!p_prev) |
| 307 | (*this)->hash[hash] = &((*this)->member[i]); |
| 308 | else |
| 309 | p_prev->nexthash = &((*this)->member[i]); |
| 310 | } |
| 311 | /*ippool_printaddr(*this);*/ |
| 312 | return 0; |
| 313 | } |
| 314 | |
| 315 | /* Delete existing address pool */ |
| 316 | int ippool_free(struct ippool_t *this) { |
| 317 | free(this->hash); |
| 318 | free(this->member); |
| 319 | free(this); |
| 320 | return 0; /* Always OK */ |
| 321 | } |
| 322 | |
| 323 | /* Find an IP address in the pool */ |
| 324 | int ippool_getip(struct ippool_t *this, struct ippoolm_t **member, |
| 325 | struct in_addr *addr) { |
| 326 | struct ippoolm_t *p; |
| 327 | uint32_t hash; |
| 328 | |
| 329 | /* Find in hash table */ |
| 330 | hash = ippool_hash4(addr) & this->hashmask; |
| 331 | for (p = this->hash[hash]; p; p = p->nexthash) { |
| 332 | if ((p->addr.s_addr == addr->s_addr) && (p->inuse)) { |
| 333 | *member = p; |
| 334 | return 0; |
| 335 | } |
| 336 | } |
| 337 | *member = NULL; |
| 338 | return -1; /* Address could not be found */ |
| 339 | } |
| 340 | |
| 341 | |
| 342 | /* Get an IP address. If addr = 0.0.0.0 get a dynamic IP address. Otherwise |
| 343 | check to see if the given address is available */ |
| 344 | int ippool_newip(struct ippool_t *this, struct ippoolm_t **member, |
| 345 | struct in_addr *addr) { |
| 346 | struct ippoolm_t *p; |
| 347 | struct ippoolm_t *p2 = NULL; |
| 348 | uint32_t hash; |
| 349 | |
| 350 | /*ippool_printaddr(this);*/ |
| 351 | |
| 352 | if ((addr) && (addr->s_addr)) { /* IP address given */ |
| 353 | /* Find in hash table */ |
| 354 | hash = ippool_hash4(addr) & this->hashmask; |
| 355 | for (p = this->hash[hash]; p; p = p->nexthash) { |
| 356 | if ((p->addr.s_addr == addr->s_addr)) { |
| 357 | p2 = p; |
| 358 | break; |
| 359 | } |
| 360 | } |
| 361 | } |
| 362 | else { /* No ip address given */ |
| 363 | p2 = this -> first; |
| 364 | } |
| 365 | |
| 366 | if (!p2) return -1; /* Not found */ |
| 367 | if (p2->inuse) return -1; /* Allready in use / Should not happen */ |
| 368 | |
| 369 | /* Found new address. Remove from queue */ |
| 370 | if (p2->prev) |
| 371 | p2->prev->next = p2->next; |
| 372 | else |
| 373 | this->first = p2->next; |
| 374 | if (p2->next) |
| 375 | p2->next->prev = p2->prev; |
| 376 | else |
| 377 | this->last = p2->prev; |
| 378 | p2->next = NULL; |
| 379 | p2->prev = NULL; |
| 380 | p2->inuse = 1; |
| 381 | |
| 382 | *member = p2; |
| 383 | /*ippool_printaddr(this);*/ |
| 384 | return 0; /* Success */ |
| 385 | } |
| 386 | |
| 387 | |
| 388 | int ippool_freeip(struct ippoolm_t *member) { |
| 389 | struct ippool_t *this = member->parent; |
| 390 | |
| 391 | /*ippool_printaddr(this);*/ |
| 392 | |
| 393 | if (!member->inuse) return -1; /* Not in use: Should not happen */ |
| 394 | |
| 395 | /* Insert into list of unused */ |
| 396 | member->prev = this->last; |
| 397 | if (this->last) { |
| 398 | this->last->next = member; |
| 399 | } |
| 400 | else { |
| 401 | this->first = member; |
| 402 | } |
| 403 | this->last = member; |
| 404 | |
| 405 | member->inuse = 0; |
| 406 | /*ippool_printaddr(this);*/ |
| 407 | |
| 408 | return 0; /* Success */ |
| 409 | } |
| 410 | |
| 411 | |
| 412 | #ifndef IPPOOL_NOIP6 |
| 413 | extern unsigned long int ippool_hash6(struct in6_addr *addr); |
| 414 | extern int ippool_getip6(struct ippool_t *this, struct in6_addr *addr); |
| 415 | extern int ippool_returnip6(struct ippool_t *this, struct in6_addr *addr); |
| 416 | #endif |