| 1 | /* The 'ipset' data structure and related algorithms in this file were |
| 2 | inspired by the 'ipaddr.py' library from Cendio Systems AB. */ |
| 3 | /* |
| 4 | * This file is part of secnet. |
| 5 | * See README for full list of copyright holders. |
| 6 | * |
| 7 | * secnet is free software; you can redistribute it and/or modify it |
| 8 | * under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version d of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * secnet is distributed in the hope that it will be useful, but |
| 13 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * version 3 along with secnet; if not, see |
| 19 | * https://www.gnu.org/licenses/gpl.html. |
| 20 | */ |
| 21 | |
| 22 | #include "secnet.h" |
| 23 | #include <limits.h> |
| 24 | #include <assert.h> |
| 25 | #include <stdio.h> |
| 26 | #include <string.h> |
| 27 | #include "ipaddr.h" |
| 28 | #include "util.h" |
| 29 | |
| 30 | #define DEFAULT_ALLOC 2 |
| 31 | #define EXTEND_ALLOC_BY 4 |
| 32 | |
| 33 | struct subnet_list *subnet_list_new(void) |
| 34 | { |
| 35 | struct subnet_list *r; |
| 36 | NEW(r); |
| 37 | r->entries=0; |
| 38 | r->alloc=DEFAULT_ALLOC; |
| 39 | NEW_ARY(r->list,r->alloc); |
| 40 | return r; |
| 41 | } |
| 42 | |
| 43 | void subnet_list_free(struct subnet_list *a) |
| 44 | { |
| 45 | if (a->list) free(a->list); |
| 46 | free(a); |
| 47 | } |
| 48 | |
| 49 | static void subnet_list_set_len(struct subnet_list *a, int32_t l) |
| 50 | { |
| 51 | int32_t na; |
| 52 | |
| 53 | if (l>a->alloc) { |
| 54 | assert(a->alloc < INT_MAX-EXTEND_ALLOC_BY); |
| 55 | na=a->alloc+EXTEND_ALLOC_BY; |
| 56 | REALLOC_ARY(a->list,na); |
| 57 | a->alloc=na; |
| 58 | } |
| 59 | a->entries=l; |
| 60 | } |
| 61 | |
| 62 | void subnet_list_append(struct subnet_list *a, uint32_t prefix, int len) |
| 63 | { |
| 64 | struct subnet *sn; |
| 65 | assert(a->entries < INT_MAX); |
| 66 | subnet_list_set_len(a,a->entries+1); |
| 67 | sn=&a->list[a->entries-1]; |
| 68 | sn->prefix=prefix; |
| 69 | sn->len=len; |
| 70 | sn->mask=len?(0xffffffff << (32-len)):0; |
| 71 | } |
| 72 | |
| 73 | struct ipset *ipset_new(void) |
| 74 | { |
| 75 | struct ipset *r; |
| 76 | NEW(r); |
| 77 | r->l=0; |
| 78 | r->a=DEFAULT_ALLOC; |
| 79 | NEW_ARY(r->d,r->a); |
| 80 | return r; |
| 81 | } |
| 82 | |
| 83 | void ipset_free(struct ipset *a) |
| 84 | { |
| 85 | if (a->d) free(a->d); |
| 86 | free(a); |
| 87 | } |
| 88 | |
| 89 | #ifdef DEBUG |
| 90 | static void ipset_dump(struct ipset *a, string_t name) |
| 91 | { |
| 92 | int32_t i; |
| 93 | |
| 94 | printf("%s: ",name); |
| 95 | for (i=0; i<a->l; i++) { |
| 96 | printf("[%08x-%08x] ",a->d[i].a,a->d[i].b); |
| 97 | } |
| 98 | printf("\n"); |
| 99 | } |
| 100 | #endif |
| 101 | |
| 102 | struct ipset *ipset_from_subnet(struct subnet s) |
| 103 | { |
| 104 | struct ipset *r; |
| 105 | |
| 106 | r=ipset_new(); |
| 107 | r->l=1; |
| 108 | r->d[0].a=s.prefix; |
| 109 | r->d[0].b=s.prefix | (~s.mask); |
| 110 | return r; |
| 111 | } |
| 112 | |
| 113 | struct ipset *ipset_from_subnet_list(struct subnet_list *l) |
| 114 | { |
| 115 | struct ipset *r, *a, *b; |
| 116 | int32_t i; |
| 117 | |
| 118 | r=ipset_new(); |
| 119 | for (i=0; i<l->entries; i++) { |
| 120 | a=ipset_from_subnet(l->list[i]); |
| 121 | b=ipset_union(r,a); |
| 122 | ipset_free(a); |
| 123 | ipset_free(r); |
| 124 | r=b; |
| 125 | } |
| 126 | return r; |
| 127 | } |
| 128 | |
| 129 | static void ipset_set_len(struct ipset *a, int32_t l) |
| 130 | { |
| 131 | int32_t na; |
| 132 | |
| 133 | if (l>a->a) { |
| 134 | assert(a->a < INT_MAX-EXTEND_ALLOC_BY); |
| 135 | na=a->a+EXTEND_ALLOC_BY; |
| 136 | REALLOC_ARY(a->d,na); |
| 137 | a->a=na; |
| 138 | } |
| 139 | a->l=l; |
| 140 | } |
| 141 | |
| 142 | static void ipset_append_range(struct ipset *a, struct iprange r) |
| 143 | { |
| 144 | ipset_set_len(a,a->l+1); |
| 145 | a->d[a->l-1]=r; |
| 146 | } |
| 147 | |
| 148 | struct ipset *ipset_union(struct ipset *a, struct ipset *b) |
| 149 | { |
| 150 | struct ipset *c; |
| 151 | struct iprange r; |
| 152 | int32_t ia,ib; |
| 153 | |
| 154 | c=ipset_new(); |
| 155 | ia=0; ib=0; |
| 156 | while (ia<a->l || ib<b->l) { |
| 157 | if (ia<a->l) |
| 158 | if (ib<b->l) |
| 159 | if (a->d[ia].a < b->d[ib].a) |
| 160 | r=a->d[ia++]; |
| 161 | else |
| 162 | r=b->d[ib++]; |
| 163 | else |
| 164 | r=a->d[ia++]; |
| 165 | else |
| 166 | r=b->d[ib++]; |
| 167 | |
| 168 | if (c->l==0) |
| 169 | ipset_append_range(c,r); |
| 170 | else if (r.a <= c->d[c->l-1].b+1) |
| 171 | /* Extends (or is consumed by) the last range */ |
| 172 | c->d[c->l-1].b=MAX(c->d[c->l-1].b, r.b); |
| 173 | else |
| 174 | ipset_append_range(c,r); |
| 175 | } |
| 176 | return c; |
| 177 | } |
| 178 | |
| 179 | struct ipset *ipset_intersection(struct ipset *a, struct ipset *b) |
| 180 | { |
| 181 | struct ipset *r; |
| 182 | struct iprange ra, rb; |
| 183 | int32_t ia,ib; |
| 184 | |
| 185 | r=ipset_new(); |
| 186 | ia=0; ib=0; |
| 187 | |
| 188 | while (ia<a->l && ib<b->l) { |
| 189 | ra=a->d[ia]; |
| 190 | rb=b->d[ib]; |
| 191 | if (ra.b < rb.a) |
| 192 | /* The first entry of a doesn't overlap with any part of b */ |
| 193 | ia++; |
| 194 | else if (ra.a > rb.b) |
| 195 | /* The first entry of b doesn't overlap with any part of a */ |
| 196 | ib++; |
| 197 | else { |
| 198 | /* Trim away any leading edges */ |
| 199 | if (ra.a < rb.a) |
| 200 | /* a starts before b */ |
| 201 | ra.a=rb.a; |
| 202 | else if (ra.a > rb.a) |
| 203 | /* b starts before a */ |
| 204 | rb.a=ra.a; |
| 205 | |
| 206 | /* Now the ranges start at the same point */ |
| 207 | if (ra.b == rb.b) { |
| 208 | /* The ranges are equal */ |
| 209 | ipset_append_range(r,ra); |
| 210 | ia++; |
| 211 | ib++; |
| 212 | } else if (ra.b < rb.b) { |
| 213 | /* a is the smaller range */ |
| 214 | ipset_append_range(r,ra); |
| 215 | ia++; |
| 216 | } else { |
| 217 | /* y is the smaller range */ |
| 218 | ipset_append_range(r,rb); |
| 219 | ib++; |
| 220 | } |
| 221 | } |
| 222 | } |
| 223 | return r; |
| 224 | } |
| 225 | |
| 226 | struct ipset *ipset_complement(struct ipset *a) |
| 227 | { |
| 228 | struct ipset *r; |
| 229 | struct iprange n; |
| 230 | int64_t pre; |
| 231 | int32_t i; |
| 232 | uint32_t lo,hi; |
| 233 | |
| 234 | r=ipset_new(); |
| 235 | pre=-1; |
| 236 | for (i=0; i<a->l; i++) { |
| 237 | lo=a->d[i].a; |
| 238 | hi=a->d[i].b; |
| 239 | if (lo!=0) { |
| 240 | n.a=pre+1; |
| 241 | n.b=lo-1; |
| 242 | ipset_append_range(r,n); |
| 243 | } |
| 244 | pre=hi; |
| 245 | } |
| 246 | if (pre!=0xffffffff) { |
| 247 | n.a=pre+1; |
| 248 | n.b=0xffffffff; |
| 249 | ipset_append_range(r,n); |
| 250 | } |
| 251 | return r; |
| 252 | } |
| 253 | |
| 254 | /* Return a-b */ |
| 255 | struct ipset *ipset_subtract(struct ipset *a, struct ipset *b) |
| 256 | { |
| 257 | struct ipset *c, *r; |
| 258 | c=ipset_complement(b); |
| 259 | r=ipset_intersection(a,c); |
| 260 | ipset_free(c); |
| 261 | return r; |
| 262 | } |
| 263 | |
| 264 | bool_t ipset_is_empty(struct ipset *a) |
| 265 | { |
| 266 | return (a->l==0); |
| 267 | } |
| 268 | |
| 269 | bool_t ipset_contains_addr(struct ipset *a, uint32_t addr) |
| 270 | { |
| 271 | int32_t i; |
| 272 | struct iprange r; |
| 273 | |
| 274 | for (i=0; i<a->l; i++) { |
| 275 | r=a->d[i]; |
| 276 | if (addr>=r.a && addr<=r.b) return True; |
| 277 | if (addr<r.a) return False; |
| 278 | } |
| 279 | return False; |
| 280 | } |
| 281 | |
| 282 | /* sub is a subset of super if it does not intersect with the complement |
| 283 | of super */ |
| 284 | bool_t ipset_is_subset(struct ipset *super, struct ipset *sub) |
| 285 | { |
| 286 | struct ipset *superc; |
| 287 | struct ipset *inter; |
| 288 | bool_t empty; |
| 289 | |
| 290 | superc=ipset_complement(super); |
| 291 | inter=ipset_intersection(superc,sub); |
| 292 | empty=ipset_is_empty(inter); |
| 293 | ipset_free(inter); |
| 294 | ipset_free(superc); |
| 295 | return empty; |
| 296 | } |
| 297 | |
| 298 | struct subnet_list *ipset_to_subnet_list(struct ipset *is) |
| 299 | { |
| 300 | struct subnet_list *r; |
| 301 | int64_t a,b,lobit,himask,lomask; |
| 302 | int bits; |
| 303 | int32_t i; |
| 304 | |
| 305 | r=subnet_list_new(); |
| 306 | for (i=0; i<is->l; i++) { |
| 307 | a=is->d[i].a; |
| 308 | b=is->d[i].b; |
| 309 | |
| 310 | lomask=1; |
| 311 | lobit=1; |
| 312 | himask=0xfffffffe; |
| 313 | bits=32; |
| 314 | while (a<=b) { |
| 315 | if ((a & lomask) != 0) { |
| 316 | subnet_list_append(r,a,bits); |
| 317 | a=a+lobit; |
| 318 | } else if ((b & lomask) != lomask) { |
| 319 | subnet_list_append(r,b&himask,bits); |
| 320 | b=b-lobit; |
| 321 | } else { |
| 322 | lomask = (lomask << 1) | 1; |
| 323 | lobit = (lobit << 1); |
| 324 | himask = himask ^ lobit; |
| 325 | bits = bits - 1; |
| 326 | ASSERT(bits>=0); |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | /* Sort the list? */ |
| 331 | return r; |
| 332 | } |
| 333 | |
| 334 | #define IPADDR_BUFLEN 20 |
| 335 | |
| 336 | static char *ipaddr_getbuf(void) |
| 337 | { |
| 338 | SBUF_DEFINE(16, IPADDR_BUFLEN); |
| 339 | return SBUF; |
| 340 | } |
| 341 | |
| 342 | /* The string buffer must be at least 16 bytes long */ |
| 343 | string_t ipaddr_to_string(uint32_t addr) |
| 344 | { |
| 345 | uint8_t a,b,c,d; |
| 346 | string_t s; |
| 347 | |
| 348 | s=ipaddr_getbuf(); |
| 349 | a=addr>>24; |
| 350 | b=addr>>16; |
| 351 | c=addr>>8; |
| 352 | d=addr; |
| 353 | snprintf(s, 16, "%d.%d.%d.%d", a, b, c, d); |
| 354 | return s; |
| 355 | } |
| 356 | |
| 357 | string_t subnet_to_string(struct subnet sn) |
| 358 | { |
| 359 | uint32_t addr=sn.prefix; |
| 360 | uint8_t a,b,c,d; |
| 361 | string_t s; |
| 362 | |
| 363 | s=ipaddr_getbuf(); |
| 364 | a=addr>>24; |
| 365 | b=addr>>16; |
| 366 | c=addr>>8; |
| 367 | d=addr; |
| 368 | snprintf(s, 19, "%d.%d.%d.%d/%d", a, b, c, d, sn.len); |
| 369 | return s; |
| 370 | } |
| 371 | |
| 372 | static struct subnet string_item_to_subnet(item_t *i, cstring_t desc, |
| 373 | bool_t *invert) |
| 374 | { |
| 375 | struct subnet s; |
| 376 | uint32_t a, b, c, d, n; |
| 377 | int match; |
| 378 | cstring_t in; |
| 379 | |
| 380 | *invert=False; |
| 381 | |
| 382 | /* i is not guaranteed to be a string */ |
| 383 | if (i->type!=t_string) { |
| 384 | cfgfatal(i->loc,desc,"expecting a string (subnet specification)\n"); |
| 385 | } |
| 386 | in=i->data.string; |
| 387 | |
| 388 | if (strcmp(in,"default")==0) { |
| 389 | s.prefix=0; |
| 390 | s.mask=0; |
| 391 | s.len=0; |
| 392 | return s; |
| 393 | } |
| 394 | |
| 395 | if (*in=='!') { |
| 396 | *invert=True; |
| 397 | in++; |
| 398 | } |
| 399 | /* We expect strings of the form "a.b.c.d[/n]", i.e. the dots are |
| 400 | NOT optional. The subnet mask is optional; if missing it is assumed |
| 401 | to be /32. */ |
| 402 | match=sscanf(in,"%u.%u.%u.%u/%u", &a, &b, &c, &d, &n); |
| 403 | if (match<4) { |
| 404 | cfgfatal(i->loc,desc,"\"%s\" is not a valid " |
| 405 | "subnet specification\n",in); |
| 406 | } |
| 407 | if (match<5) { |
| 408 | n=32; |
| 409 | } |
| 410 | if (a>255 || b>255 || c>255 || d>255 || n>32) { |
| 411 | cfgfatal(i->loc,desc,"\"%s\": range error\n",in); |
| 412 | } |
| 413 | s.prefix=(a<<24)|(b<<16)|(c<<8)|(d); |
| 414 | s.mask=n?(~0UL << (32-n)):0; |
| 415 | s.len=n; |
| 416 | if (s.prefix & ~s.mask) { |
| 417 | cfgfatal(i->loc,desc,"\"%s\": prefix not fully contained " |
| 418 | "in mask\n",in); |
| 419 | } |
| 420 | return s; |
| 421 | } |
| 422 | |
| 423 | uint32_t string_item_to_ipaddr(const item_t *i, cstring_t desc) |
| 424 | { |
| 425 | uint32_t a, b, c, d; |
| 426 | int match; |
| 427 | |
| 428 | /* i is not guaranteed to be a string */ |
| 429 | if (i->type!=t_string) { |
| 430 | cfgfatal(i->loc,desc,"expecting a string (IP address)\n"); |
| 431 | } |
| 432 | |
| 433 | match=sscanf(i->data.string,"%u.%u.%u.%u", &a, &b, &c, &d); |
| 434 | if (match<4) { |
| 435 | cfgfatal(i->loc,desc,"\"%s\" is not a valid " |
| 436 | "IP address\n",i->data.string); |
| 437 | } |
| 438 | if (a>255 || b>255 || c>255 || d>255) { |
| 439 | cfgfatal(i->loc,desc,"\"%s\": range error\n",i->data.string); |
| 440 | } |
| 441 | return (a<<24)|(b<<16)|(c<<8)|(d); |
| 442 | } |
| 443 | |
| 444 | struct ipset *string_list_to_ipset(list_t *l, struct cloc loc, |
| 445 | cstring_t module, cstring_t param) |
| 446 | { |
| 447 | struct ipset *r, *n, *isn; |
| 448 | uint32_t e,i; |
| 449 | item_t *item; |
| 450 | bool_t inv; |
| 451 | |
| 452 | r=ipset_new(); |
| 453 | e=list_length(l); |
| 454 | for (i=0; i<e; i++) { |
| 455 | item=list_elem(l,i); |
| 456 | isn=ipset_from_subnet(string_item_to_subnet(item,param,&inv)); |
| 457 | if (inv) { |
| 458 | n=ipset_subtract(r,isn); |
| 459 | } else { |
| 460 | n=ipset_union(r,isn); |
| 461 | } |
| 462 | ipset_free(r); |
| 463 | ipset_free(isn); |
| 464 | r=n; |
| 465 | } |
| 466 | return r; |
| 467 | } |