| 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 | #include <inttypes.h> |
| 32 | #include <stddef.h> |
| 33 | #include <stdbool.h> |
| 34 | |
| 35 | #include <sys/types.h> |
| 36 | #include <sys/socket.h> |
| 37 | #include <netinet/in.h> |
| 38 | #include <arpa/inet.h> |
| 39 | #include <net/if.h> |
| 40 | |
| 41 | #include "internal.h" |
| 42 | |
| 43 | /* |
| 44 | * General address-family operations. |
| 45 | */ |
| 46 | |
| 47 | #define SIN(sa) ((struct sockaddr_in *)(sa)) |
| 48 | #define CSIN(sa) ((const struct sockaddr_in *)(sa)) |
| 49 | |
| 50 | #define SIN6(sa) ((struct sockaddr_in6 *)(sa)) |
| 51 | #define CSIN6(sa) ((const struct sockaddr_in6 *)(sa)) |
| 52 | |
| 53 | /* This gadget (thanks, Richard Kettlewell) makes sure that we handle the |
| 54 | * same set of address families in each switch. */ |
| 55 | #define AF_CASES(pre) \ |
| 56 | case AF_INET: goto pre##_inet; \ |
| 57 | case AF_INET6: goto pre##_inet6 |
| 58 | |
| 59 | static void unknown_af(int af) { |
| 60 | fprintf(stderr, "ADNS INTERNAL: unknown address family %d\n", af); |
| 61 | abort(); |
| 62 | } |
| 63 | |
| 64 | #define IN6_ADDR_EQUALP(a, b) \ |
| 65 | (!memcmp((a).s6_addr, (b).s6_addr, sizeof((a).s6_addr))) |
| 66 | |
| 67 | int adns__genaddr_equal_p(int af, const union gen_addr *a, |
| 68 | int bf, const void *b) { |
| 69 | const union gen_addr *bb= b; |
| 70 | if (af != bf) return 0; |
| 71 | switch (af) { |
| 72 | AF_CASES(af); |
| 73 | af_inet: return a->v4.s_addr == bb->v4.s_addr; |
| 74 | af_inet6: return IN6_ADDR_EQUALP(a->v6, bb->v6); |
| 75 | default: unknown_af(af); return -1; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | int adns__sockaddr_equal_p(const struct sockaddr *sa, |
| 80 | const struct sockaddr *sb) { |
| 81 | if (sa->sa_family != sb->sa_family) return 0; |
| 82 | switch (sa->sa_family) { |
| 83 | AF_CASES(af); |
| 84 | af_inet: { |
| 85 | const struct sockaddr_in *sina= CSIN(sa), *sinb= CSIN(sb); |
| 86 | return (sina->sin_addr.s_addr == sinb->sin_addr.s_addr && |
| 87 | sina->sin_port == sinb->sin_port); |
| 88 | } |
| 89 | af_inet6: { |
| 90 | /* Don't check the flowlabel. That's apparently useful for routing |
| 91 | * performance, but doesn't affect the address in any important |
| 92 | * respect. */ |
| 93 | const struct sockaddr_in6 *sin6a= CSIN6(sa), *sin6b= CSIN6(sb); |
| 94 | return (IN6_ADDR_EQUALP(sin6a->sin6_addr, sin6b->sin6_addr) && |
| 95 | sin6a->sin6_port == sin6b->sin6_port && |
| 96 | sin6a->sin6_scope_id == sin6b->sin6_scope_id); |
| 97 | } |
| 98 | default: |
| 99 | unknown_af(sa->sa_family); |
| 100 | return -1; |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | int adns__addr_width(int af) { |
| 105 | switch (af) { |
| 106 | AF_CASES(af); |
| 107 | af_inet: return 32; |
| 108 | af_inet6: return 128; |
| 109 | default: unknown_af(af); return -1; |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | void adns__prefix_mask(int af, int len, union gen_addr *mask_r) { |
| 114 | switch (af) { |
| 115 | AF_CASES(af); |
| 116 | af_inet: |
| 117 | assert(len <= 32); |
| 118 | mask_r->v4.s_addr= htonl(!len ? 0 : 0xffffffff << (32-len)); |
| 119 | break; |
| 120 | af_inet6: { |
| 121 | int i= len/8, j= len%8; |
| 122 | unsigned char *m= mask_r->v6.s6_addr; |
| 123 | assert(len <= 128); |
| 124 | memset(m, 0xff, i); |
| 125 | if (j) m[i++]= (0xff << (8-j)) & 0xff; |
| 126 | memset(m+i, 0, 16-i); |
| 127 | } break; |
| 128 | default: |
| 129 | unknown_af(af); |
| 130 | break; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | int adns__guess_prefix_length(int af, const union gen_addr *addr) { |
| 135 | switch (af) { |
| 136 | AF_CASES(af); |
| 137 | af_inet: { |
| 138 | unsigned a= (ntohl(addr->v4.s_addr) >> 24) & 0xff; |
| 139 | if (a < 128) return 8; |
| 140 | else if (a < 192) return 16; |
| 141 | else if (a < 224) return 24; |
| 142 | else return -1; |
| 143 | } break; |
| 144 | af_inet6: |
| 145 | return 64; |
| 146 | default: |
| 147 | unknown_af(af); |
| 148 | return -1; |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | int adns__addr_match_p(int addraf, const union gen_addr *addr, |
| 153 | int netaf, const union gen_addr *base, |
| 154 | const union gen_addr *mask) |
| 155 | { |
| 156 | if (addraf != netaf) return 0; |
| 157 | switch (addraf) { |
| 158 | AF_CASES(af); |
| 159 | af_inet: |
| 160 | return (addr->v4.s_addr & mask->v4.s_addr) == base->v4.s_addr; |
| 161 | af_inet6: { |
| 162 | int i; |
| 163 | const char *a= addr->v6.s6_addr; |
| 164 | const char *b= base->v6.s6_addr; |
| 165 | const char *m= mask->v6.s6_addr; |
| 166 | for (i = 0; i < 16; i++) |
| 167 | if ((a[i] & m[i]) != b[i]) return 0; |
| 168 | return 1; |
| 169 | } break; |
| 170 | default: |
| 171 | unknown_af(addraf); |
| 172 | return -1; |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | void adns__sockaddr_extract(const struct sockaddr *sa, |
| 177 | union gen_addr *a_r, int *port_r) { |
| 178 | switch (sa->sa_family) { |
| 179 | AF_CASES(af); |
| 180 | af_inet: { |
| 181 | const struct sockaddr_in *sin = CSIN(sa); |
| 182 | if (port_r) *port_r= ntohs(sin->sin_port); |
| 183 | if (a_r) a_r->v4= sin->sin_addr; |
| 184 | break; |
| 185 | } |
| 186 | af_inet6: { |
| 187 | const struct sockaddr_in6 *sin6 = CSIN6(sa); |
| 188 | if (port_r) *port_r= ntohs(sin6->sin6_port); |
| 189 | if (a_r) a_r->v6= sin6->sin6_addr; |
| 190 | break; |
| 191 | } |
| 192 | default: |
| 193 | unknown_af(sa->sa_family); |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | void adns__sockaddr_inject(const union gen_addr *a, int port, |
| 198 | struct sockaddr *sa) { |
| 199 | switch (sa->sa_family) { |
| 200 | AF_CASES(af); |
| 201 | af_inet: { |
| 202 | struct sockaddr_in *sin = SIN(sa); |
| 203 | if (port != -1) sin->sin_port= htons(port); |
| 204 | if (a) sin->sin_addr= a->v4; |
| 205 | break; |
| 206 | } |
| 207 | af_inet6: { |
| 208 | struct sockaddr_in6 *sin6 = SIN6(sa); |
| 209 | if (port != -1) sin6->sin6_port= htons(port); |
| 210 | if (a) sin6->sin6_addr= a->v6; |
| 211 | break; |
| 212 | } |
| 213 | default: |
| 214 | unknown_af(sa->sa_family); |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | /* |
| 219 | * addr2text and text2addr |
| 220 | */ |
| 221 | |
| 222 | #define ADDRFAM_DEBUG |
| 223 | #ifdef ADDRFAM_DEBUG |
| 224 | static void af_debug_func(const char *fmt, ...) { |
| 225 | int esave= errno; |
| 226 | va_list al; |
| 227 | va_start(al,fmt); |
| 228 | vfprintf(stderr,fmt,al); |
| 229 | va_end(al); |
| 230 | errno= esave; |
| 231 | } |
| 232 | # define af_debug(fmt,...) \ |
| 233 | (af_debug_func("%s: " fmt "\n", __func__, __VA_ARGS__)) |
| 234 | #else |
| 235 | # define af_debug(fmt,...) ((void)("" fmt "", __VA_ARGS__)) |
| 236 | #endif |
| 237 | |
| 238 | static bool addrtext_our_errno(int e) { |
| 239 | return |
| 240 | e==EAFNOSUPPORT || |
| 241 | e==EINVAL || |
| 242 | e==ENOSPC || |
| 243 | e==ENOSYS; |
| 244 | } |
| 245 | |
| 246 | static bool addrtext_scope_use_ifname(const struct sockaddr *sa) { |
| 247 | const struct in6_addr *in6= &CSIN6(sa)->sin6_addr; |
| 248 | return |
| 249 | IN6_IS_ADDR_LINKLOCAL(in6) || |
| 250 | IN6_IS_ADDR_MC_LINKLOCAL(in6); |
| 251 | } |
| 252 | |
| 253 | int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags, |
| 254 | struct sockaddr *sa, socklen_t *salen_io) { |
| 255 | int af; |
| 256 | char copybuf[INET6_ADDRSTRLEN]; |
| 257 | const char *parse=text; |
| 258 | const char *scopestr=0; |
| 259 | socklen_t needlen; |
| 260 | void *dst; |
| 261 | uint16_t *portp; |
| 262 | |
| 263 | #define INVAL(how) do{ \ |
| 264 | af_debug("invalid: %s: `%s'", how, text); \ |
| 265 | return EINVAL; \ |
| 266 | }while(0) |
| 267 | |
| 268 | #define AFCORE(INETx,SINx,sinx) \ |
| 269 | af= AF_##INETx; \ |
| 270 | dst = &SINx(sa)->sinx##_addr; \ |
| 271 | portp = &SINx(sa)->sinx##_port; \ |
| 272 | needlen= sizeof(*SINx(sa)); |
| 273 | |
| 274 | if (!strchr(text, ':')) { /* INET */ |
| 275 | |
| 276 | AFCORE(INET,SIN,sin); |
| 277 | |
| 278 | } else { /* INET6 */ |
| 279 | |
| 280 | AFCORE(INET6,SIN6,sin6); |
| 281 | |
| 282 | const char *percent= strchr(text, '%'); |
| 283 | if (percent) { |
| 284 | ptrdiff_t lhslen = percent - text; |
| 285 | if (lhslen >= INET6_ADDRSTRLEN) INVAL("scoped addr lhs too long"); |
| 286 | memcpy(copybuf, text, lhslen); |
| 287 | copybuf[lhslen]= 0; |
| 288 | |
| 289 | parse= copybuf; |
| 290 | scopestr= percent+1; |
| 291 | |
| 292 | af_debug("will parse scoped addr `%s' %% `%s'", parse, scopestr); |
| 293 | } |
| 294 | |
| 295 | } |
| 296 | |
| 297 | #undef AFCORE |
| 298 | |
| 299 | if (scopestr && (flags & adns_qf_addrlit_scope_forbid)) |
| 300 | INVAL("scoped addr but _scope_forbid"); |
| 301 | |
| 302 | if (*salen_io < needlen) { |
| 303 | *salen_io = needlen; |
| 304 | return ENOSPC; |
| 305 | } |
| 306 | |
| 307 | memset(sa, 0, needlen); |
| 308 | |
| 309 | sa->sa_family= af; |
| 310 | *portp = htons(port); |
| 311 | |
| 312 | if (af == AF_INET && !(flags & adns_qf_addrlit_ipv4_quadonly)) { |
| 313 | /* we have to use inet_aton to deal with non-dotted-quad literals */ |
| 314 | int r= inet_aton(parse,&SIN(sa)->sin_addr); |
| 315 | if (!r) INVAL("inet_aton rejected"); |
| 316 | } else { |
| 317 | int r= inet_pton(af,parse,dst); |
| 318 | if (!r) INVAL("inet_pton rejected"); |
| 319 | assert(r>0); |
| 320 | } |
| 321 | |
| 322 | if (scopestr) { |
| 323 | errno=0; |
| 324 | char *ep; |
| 325 | unsigned long scope= strtoul(scopestr,&ep,10); |
| 326 | if (errno==ERANGE) INVAL("numeric scope id too large for unsigned long"); |
| 327 | assert(!errno); |
| 328 | if (!*ep) { |
| 329 | if (scope > ~(uint32_t)0) |
| 330 | INVAL("numeric scope id too large for uint32_t"); |
| 331 | } else { /* !!*ep */ |
| 332 | if (flags & adns_qf_addrlit_scope_numeric) |
| 333 | INVAL("non-numeric scope but _scope_numeric"); |
| 334 | if (!addrtext_scope_use_ifname(sa)) { |
| 335 | af_debug("cannot convert non-numeric scope" |
| 336 | " in non-link-local addr `%s'", text); |
| 337 | return ENOSYS; |
| 338 | } |
| 339 | errno= 0; |
| 340 | scope= if_nametoindex(scopestr); |
| 341 | if (!scope) { |
| 342 | /* RFC3493 says "No errors are defined". It's not clear |
| 343 | * whether that is supposed to mean if_nametoindex "can't |
| 344 | * fail" (other than by the supplied name not being that of an |
| 345 | * interface) which seems unrealistic, or that it conflates |
| 346 | * all its errors together by failing to set errno, or simply |
| 347 | * that they didn't bother to document the errors. |
| 348 | * |
| 349 | * glibc, FreeBSD and OpenBSD all set errno (to ENXIO when |
| 350 | * appropriate). See Debian bug #749349. |
| 351 | * |
| 352 | * We attempt to deal with this by clearing errno to start |
| 353 | * with, and then perhaps mapping the results. */ |
| 354 | af_debug("if_nametoindex rejected scope name (errno=%s)", |
| 355 | strerror(errno)); |
| 356 | if (errno==0) { |
| 357 | return ENXIO; |
| 358 | } else if (addrtext_our_errno(errno)) { |
| 359 | /* we use these for other purposes, urgh. */ |
| 360 | perror("adns: adns_text2addr: if_nametoindex" |
| 361 | " failed with unexpected error"); |
| 362 | return EIO; |
| 363 | } else { |
| 364 | return errno; |
| 365 | } |
| 366 | } else { /* ix>0 */ |
| 367 | if (scope > ~(uint32_t)0) { |
| 368 | fprintf(stderr,"adns: adns_text2addr: if_nametoindex" |
| 369 | " returned an interface index >=2^32 which will not fit" |
| 370 | " in sockaddr_in6.sin6_scope_id"); |
| 371 | return EIO; |
| 372 | } |
| 373 | } |
| 374 | } /* else; !!*ep */ |
| 375 | |
| 376 | SIN6(sa)->sin6_scope_id= scope; |
| 377 | } /* if (scopestr) */ |
| 378 | |
| 379 | *salen_io = needlen; |
| 380 | return 0; |
| 381 | } |
| 382 | |
| 383 | int adns_addr2text(const struct sockaddr *sa, adns_queryflags flags, |
| 384 | char *buffer, int *buflen_io, int *port_r) { |
| 385 | const void *src; |
| 386 | int port; |
| 387 | |
| 388 | if (*buflen_io < ADNS_ADDR2TEXT_BUFLEN) { |
| 389 | *buflen_io = ADNS_ADDR2TEXT_BUFLEN; |
| 390 | return ENOSPC; |
| 391 | } |
| 392 | |
| 393 | switch (sa->sa_family) { |
| 394 | AF_CASES(af); |
| 395 | af_inet: src= &CSIN(sa)->sin_addr; port= CSIN(sa)->sin_port; break; |
| 396 | af_inet6: src= &CSIN6(sa)->sin6_addr; port= CSIN6(sa)->sin6_port; break; |
| 397 | default: return EAFNOSUPPORT; |
| 398 | } |
| 399 | |
| 400 | const char *ok= inet_ntop(sa->sa_family, src, buffer, *buflen_io); |
| 401 | assert(ok); |
| 402 | |
| 403 | if (sa->sa_family == AF_INET6) { |
| 404 | uint32_t scope = CSIN6(sa)->sin6_scope_id; |
| 405 | if (scope) { |
| 406 | if (flags & adns_qf_addrlit_scope_forbid) |
| 407 | return EINVAL; |
| 408 | int scopeoffset = strlen(buffer); |
| 409 | int remain = *buflen_io - scopeoffset; |
| 410 | char *scopeptr = buffer + scopeoffset; |
| 411 | assert(remain >= IF_NAMESIZE+1/*%*/); |
| 412 | *scopeptr++= '%'; remain--; |
| 413 | bool parsedname = 0; |
| 414 | af_debug("will print scoped addr `%.*s' %% %"PRIu32"", |
| 415 | scopeoffset,buffer, scope); |
| 416 | if (scope <= UINT_MAX /* so we can pass it to if_indextoname */ |
| 417 | && !(flags & adns_qf_addrlit_scope_numeric) |
| 418 | && addrtext_scope_use_ifname(sa)) { |
| 419 | parsedname = if_indextoname(scope, scopeptr); |
| 420 | if (!parsedname) { |
| 421 | af_debug("if_indextoname rejected scope (errno=%s)", |
| 422 | strerror(errno)); |
| 423 | if (errno==ENXIO) { |
| 424 | /* fair enough, show it as a number then */ |
| 425 | } else if (addrtext_our_errno(errno)) { |
| 426 | /* we use these for other purposes, urgh. */ |
| 427 | perror("adns: adns_addr2text: if_indextoname" |
| 428 | " failed with unexpected error"); |
| 429 | return EIO; |
| 430 | } else { |
| 431 | return errno; |
| 432 | } |
| 433 | } |
| 434 | } |
| 435 | if (!parsedname) { |
| 436 | int r = snprintf(scopeptr, remain, |
| 437 | "%"PRIu32"", scope); |
| 438 | assert(r < *buflen_io - scopeoffset); |
| 439 | } |
| 440 | af_debug("printed scoped addr `%s'", buffer); |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | if (port_r) *port_r= ntohs(port); |
| 445 | return 0; |
| 446 | } |