| 1 | /* |
| 2 | * addrfam.c |
| 3 | * - address-family specific code |
| 4 | */ |
| 5 | /* |
| 6 | * This file is part of adns, which is |
| 7 | * Copyright (C) 1997-2000,2003,2006 Ian Jackson |
| 8 | * Copyright (C) 1999-2000,2003,2006 Tony Finch |
| 9 | * Copyright (C) 1991 Massachusetts Institute of Technology |
| 10 | * (See the file INSTALL for full details.) |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2, or (at your option) |
| 15 | * any later version. |
| 16 | * |
| 17 | * This program is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with this program; if not, write to the Free Software Foundation, |
| 24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | #include <stdlib.h> |
| 28 | #include <errno.h> |
| 29 | #include <limits.h> |
| 30 | #include <unistd.h> |
| 31 | |
| 32 | #include <sys/types.h> |
| 33 | #include <netdb.h> |
| 34 | #include <sys/socket.h> |
| 35 | #include <netinet/in.h> |
| 36 | #include <arpa/inet.h> |
| 37 | |
| 38 | #include "internal.h" |
| 39 | |
| 40 | /* |
| 41 | * General address-family operations. |
| 42 | */ |
| 43 | |
| 44 | #define SIN(sa) ((struct sockaddr_in *)(sa)) |
| 45 | #define CSIN(sa) ((const struct sockaddr_in *)(sa)) |
| 46 | |
| 47 | #define SIN6(sa) ((struct sockaddr_in6 *)(sa)) |
| 48 | #define CSIN6(sa) ((const struct sockaddr_in6 *)(sa)) |
| 49 | |
| 50 | /* This gadget (thanks, Richard Kettlewell) makes sure that we handle the |
| 51 | * same set of address families in each switch. */ |
| 52 | #define AF_CASES(pre) \ |
| 53 | case AF_INET: goto pre##_inet; \ |
| 54 | case AF_INET6: goto pre##_inet6 |
| 55 | |
| 56 | static void unknown_af(int af) { |
| 57 | fprintf(stderr, "ADNS INTERNAL: unknown address family %d\n", af); |
| 58 | abort(); |
| 59 | } |
| 60 | |
| 61 | int adns__af_supported_p(int af) |
| 62 | { |
| 63 | switch (af) { |
| 64 | AF_CASES(af); |
| 65 | af_inet: af_inet6: return 1; |
| 66 | default: return 0; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | int adns__sockaddr_equal_p(const struct sockaddr *sa, |
| 71 | const struct sockaddr *sb) |
| 72 | { |
| 73 | if (sa->sa_family != sb->sa_family) return 0; |
| 74 | switch (sa->sa_family) { |
| 75 | AF_CASES(af); |
| 76 | af_inet: { |
| 77 | const struct sockaddr_in *sina = CSIN(sa), *sinb = CSIN(sb); |
| 78 | return (sina->sin_addr.s_addr == sinb->sin_addr.s_addr && |
| 79 | sina->sin_port == sinb->sin_port); |
| 80 | } |
| 81 | af_inet6: { |
| 82 | /* Don't check the flowlabel. That's apparently useful for routing |
| 83 | * performance, but doesn't affect the address in any important |
| 84 | * respect. |
| 85 | */ |
| 86 | const struct sockaddr_in6 *sin6a = CSIN6(sa), *sin6b = CSIN6(sb); |
| 87 | return (memcmp(sin6a->sin6_addr.s6_addr, |
| 88 | sin6b->sin6_addr.s6_addr, |
| 89 | sizeof(sin6a->sin6_addr.s6_addr)) == 0 && |
| 90 | sin6a->sin6_port == sin6b->sin6_port && |
| 91 | sin6a->sin6_scope_id == sin6b->sin6_scope_id); |
| 92 | } |
| 93 | default: |
| 94 | unknown_af(sa->sa_family); |
| 95 | return -1; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | int adns__gen_pton(const char *p, int *af_r, union gen_addr *addr_r) |
| 100 | { |
| 101 | static const int aflist[] = { AF_INET6, AF_INET }; |
| 102 | int i, rc; |
| 103 | |
| 104 | for (i = 0; i < sizeof(aflist)/sizeof(*aflist); i++) { |
| 105 | rc = inet_pton(aflist[i], p, addr_r); |
| 106 | assert(rc >= 0); |
| 107 | if (rc) { *af_r = aflist[i]; return 1; } |
| 108 | } |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | int adns__addr_width(int af) |
| 113 | { |
| 114 | switch (af) { |
| 115 | AF_CASES(af); |
| 116 | af_inet: return 32; |
| 117 | af_inet6: return 128; |
| 118 | default: unknown_af(af); return -1; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | void adns__prefix_mask(int af, int len, union gen_addr *mask_r) |
| 123 | { |
| 124 | switch (af) { |
| 125 | AF_CASES(af); |
| 126 | af_inet: |
| 127 | assert(len <= 32); |
| 128 | mask_r->v4.s_addr = htonl(!len ? 0 : 0xffffffff << (32 - len)); |
| 129 | break; |
| 130 | af_inet6: { |
| 131 | int i = len/8, j = len%8; |
| 132 | unsigned char *m = mask_r->v6.s6_addr; |
| 133 | |
| 134 | assert(len <= 128); |
| 135 | memset(m, 0xff, i); |
| 136 | if (j) m[i++] = (0xff << (8-j)) & 0xff; |
| 137 | memset(m+i, 0, 16-i); |
| 138 | } break; |
| 139 | default: |
| 140 | unknown_af(af); |
| 141 | break; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | int adns__guess_prefix_length(int af, const union gen_addr *addr) |
| 146 | { |
| 147 | switch (af) { |
| 148 | AF_CASES(af); |
| 149 | af_inet: { |
| 150 | unsigned a = (ntohl(addr->v4.s_addr) >> 24) & 0xff; |
| 151 | |
| 152 | if (a < 128) return 8; |
| 153 | else if (a < 192) return 16; |
| 154 | else if (a < 224) return 24; |
| 155 | else return -1; |
| 156 | } break; |
| 157 | af_inet6: |
| 158 | return 64; |
| 159 | default: |
| 160 | unknown_af(af); |
| 161 | return -1; |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | int adns__addr_match_p(int addraf, const union gen_addr *addr, |
| 166 | int netaf, const union gen_addr *base, |
| 167 | const union gen_addr *mask) |
| 168 | { |
| 169 | if (addraf != netaf) return 0; |
| 170 | switch (addraf) { |
| 171 | AF_CASES(af); |
| 172 | af_inet: |
| 173 | return (addr->v4.s_addr & mask->v4.s_addr) == base->v4.s_addr; |
| 174 | af_inet6: { |
| 175 | int i; |
| 176 | const char *a = addr->v6.s6_addr; |
| 177 | const char *b = base->v6.s6_addr; |
| 178 | const char *m = mask->v6.s6_addr; |
| 179 | |
| 180 | for (i = 0; i < 16; i++) |
| 181 | if ((a[i] & m[i]) != b[i]) return 0; |
| 182 | return 1; |
| 183 | } break; |
| 184 | default: |
| 185 | unknown_af(addraf); |
| 186 | return -1; |
| 187 | } |
| 188 | } |
| 189 | |
| 190 | const void *adns__sockaddr_to_inaddr(const struct sockaddr *sa) |
| 191 | { |
| 192 | switch (sa->sa_family) { |
| 193 | AF_CASES(af); |
| 194 | af_inet: return &CSIN(sa)->sin_addr; |
| 195 | af_inet6: return &CSIN6(sa)->sin6_addr; |
| 196 | default: unknown_af(sa->sa_family); return 0; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * Reverse-domain parsing and construction. |
| 202 | */ |
| 203 | |
| 204 | int adns__make_reverse_domain(const struct sockaddr *sa, |
| 205 | const char *zone, |
| 206 | char **buf_io, size_t bufsz, |
| 207 | char **buf_free_r) |
| 208 | { |
| 209 | size_t req; |
| 210 | char *p; |
| 211 | unsigned c, y; |
| 212 | unsigned long aa; |
| 213 | const unsigned char *ap; |
| 214 | int i, j; |
| 215 | |
| 216 | switch (sa->sa_family) { |
| 217 | AF_CASES(af); |
| 218 | af_inet: |
| 219 | req = 4 * 4; |
| 220 | if (!zone) zone = "in-addr.arpa"; |
| 221 | break; |
| 222 | af_inet6: |
| 223 | req = 2 * 32; |
| 224 | if (!zone) zone = "ip6.arpa"; |
| 225 | break; |
| 226 | default: |
| 227 | return ENOSYS; |
| 228 | } |
| 229 | |
| 230 | req += strlen(zone) + 1; |
| 231 | if (req <= bufsz) |
| 232 | p = *buf_io; |
| 233 | else { |
| 234 | p = malloc(req); if (!p) return errno; |
| 235 | *buf_free_r = p; |
| 236 | } |
| 237 | |
| 238 | *buf_io = p; |
| 239 | switch (sa->sa_family) { |
| 240 | AF_CASES(bf); |
| 241 | bf_inet: |
| 242 | aa = ntohl(CSIN(sa)->sin_addr.s_addr); |
| 243 | for (i = 0; i < 4; i++) { |
| 244 | p += sprintf(p, "%d", (int)(aa & 0xff)); |
| 245 | *p++ = '.'; |
| 246 | aa >>= 8; |
| 247 | } |
| 248 | break; |
| 249 | bf_inet6: |
| 250 | ap = CSIN6(sa)->sin6_addr.s6_addr + 16; |
| 251 | for (i = 0; i < 16; i++) { |
| 252 | c = *--ap; |
| 253 | for (j = 0; j < 2; j++) { |
| 254 | y = c & 0xf; |
| 255 | if (y < 10) *p++ = y + '0'; |
| 256 | else *p++ = y - 10 + 'a'; |
| 257 | c >>= 4; |
| 258 | *p++ = '.'; |
| 259 | } |
| 260 | } |
| 261 | break; |
| 262 | default: |
| 263 | unknown_af(sa->sa_family); |
| 264 | } |
| 265 | |
| 266 | strcpy(p, zone); |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | |
| 271 | static int inet_rev_parsecomp(const char *p, size_t n) |
| 272 | { |
| 273 | int i = 0; |
| 274 | if (n > 3) return -1; |
| 275 | |
| 276 | while (n--) { |
| 277 | if ('0' <= *p && *p <= '9') i = 10*i + *p++ - '0'; |
| 278 | else return -1; |
| 279 | } |
| 280 | return i; |
| 281 | } |
| 282 | |
| 283 | static void inet_rev_mkaddr(union gen_addr *addr, const byte *ipv) |
| 284 | { |
| 285 | addr->v4.s_addr = htonl((ipv[3]<<24) | (ipv[2]<<16) | |
| 286 | (ipv[1]<<8) | (ipv[0])); |
| 287 | } |
| 288 | |
| 289 | static int inet6_rev_parsecomp(const char *p, size_t n) |
| 290 | { |
| 291 | if (n != 1) return -1; |
| 292 | else if ('0' <= *p && *p <= '9') return *p - '0'; |
| 293 | else if ('a' <= *p && *p <= 'f') return *p - 'a' + 10; |
| 294 | else if ('A' <= *p && *p <= 'F') return *p - 'a' + 10; |
| 295 | else return -1; |
| 296 | } |
| 297 | |
| 298 | static void inet6_rev_mkaddr(union gen_addr *addr, const byte *ipv) |
| 299 | { |
| 300 | unsigned char *a = addr->v6.s6_addr; |
| 301 | int i; |
| 302 | |
| 303 | for (i = 0; i < 16; i++) |
| 304 | a[i] = (ipv[31-2*i] << 4) | (ipv[30-2*i] << 0); |
| 305 | } |
| 306 | |
| 307 | static const struct revparse_domain { |
| 308 | int af; /* address family */ |
| 309 | int nrevlab; /* n of reverse-address labels */ |
| 310 | adns_rrtype rrtype; /* forward-lookup type */ |
| 311 | |
| 312 | int (*rev_parsecomp)(const char *p, size_t n); |
| 313 | /* parse a single component from a label; return the integer value, or -1 |
| 314 | * if it was unintelligible. |
| 315 | */ |
| 316 | |
| 317 | void (*rev_mkaddr)(union gen_addr *addr, const byte *ipv); |
| 318 | /* write out the parsed address from a vector of parsed components */ |
| 319 | |
| 320 | const char *const tail[3]; /* tail label names */ |
| 321 | } revparse_domains[NREVDOMAINS] = { |
| 322 | { AF_INET, 4, adns_r_a, inet_rev_parsecomp, inet_rev_mkaddr, |
| 323 | { DNS_INADDR_ARPA, 0 } }, |
| 324 | { AF_INET6, 32, adns_r_aaaa, inet6_rev_parsecomp, inet6_rev_mkaddr, |
| 325 | { DNS_IP6_ARPA, 0 } }, |
| 326 | }; |
| 327 | |
| 328 | #define REVDOMAIN_MAP(rps, labnum) \ |
| 329 | ((labnum) ? (rps)->map : (1 << NREVDOMAINS) - 1) |
| 330 | |
| 331 | int adns__revparse_label(struct revparse_state *rps, int labnum, |
| 332 | const char *label, int lablen) |
| 333 | { |
| 334 | unsigned f = REVDOMAIN_MAP(rps, labnum); |
| 335 | const struct revparse_domain *rpd; |
| 336 | const char *tp; |
| 337 | unsigned d; |
| 338 | int i, ac; |
| 339 | |
| 340 | for (rpd=revparse_domains, i=0, d=1; i<NREVDOMAINS; rpd++, i++, d <<= 1) { |
| 341 | if (!(f & d)) continue; |
| 342 | if (labnum >= rpd->nrevlab) { |
| 343 | tp = rpd->tail[labnum - rpd->nrevlab]; |
| 344 | if (!tp || strncmp(label, tp, lablen) != 0 || tp[lablen]) |
| 345 | goto mismatch; |
| 346 | } else { |
| 347 | ac = rpd->rev_parsecomp(label, lablen); |
| 348 | if (ac < 0) goto mismatch; |
| 349 | assert(labnum < sizeof(rps->ipv[i])); |
| 350 | rps->ipv[i][labnum] = ac; |
| 351 | } |
| 352 | continue; |
| 353 | |
| 354 | mismatch: |
| 355 | f &= ~d; |
| 356 | if (!f) return -1; |
| 357 | } |
| 358 | |
| 359 | rps->map = f; |
| 360 | return 0; |
| 361 | } |
| 362 | |
| 363 | int adns__revparse_done(struct revparse_state *rps, int nlabels, |
| 364 | adns_rrtype *rrtype_r, struct af_addr *addr_r) |
| 365 | { |
| 366 | unsigned f = REVDOMAIN_MAP(rps, nlabels); |
| 367 | const struct revparse_domain *rpd; |
| 368 | unsigned d; |
| 369 | int i, found = -1; |
| 370 | |
| 371 | for (rpd=revparse_domains, i=0, d=1; i<NREVDOMAINS; rpd++, i++, d <<= 1) { |
| 372 | if (!(f & d)) continue; |
| 373 | if (nlabels >= rpd->nrevlab && !rpd->tail[nlabels - rpd->nrevlab]) |
| 374 | { found = i; continue; } |
| 375 | f &= ~d; |
| 376 | if (!f) return -1; |
| 377 | } |
| 378 | assert(found >= 0); assert(f == (1 << found)); |
| 379 | |
| 380 | rpd = &revparse_domains[found]; |
| 381 | *rrtype_r = rpd->rrtype; |
| 382 | addr_r->af = rpd->af; |
| 383 | rpd->rev_mkaddr(&addr_r->addr, rps->ipv[found]); |
| 384 | return 0; |
| 385 | } |