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