usr.sbin/rpcbind/util.c

   1 /*
   2  * $NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $
   3  * $FreeBSD$
   4  */
   5
   6 /*-
   7  * Copyright (c) 2000 The NetBSD Foundation, Inc.
   8  * All rights reserved.
   9  *
  10  * This code is derived from software contributed to The NetBSD Foundation
  11  * by Frank van der Linden.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  24  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  25  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  26  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32  * POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/queue.h>
  38 #include <net/if.h>
  39 #include <netinet/in.h>
  40 #include <ifaddrs.h>
  41 #include <sys/poll.h>
  42 #include <rpc/rpc.h>
  43 #include <errno.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47 #include <netdb.h>
  48 #include <netconfig.h>
  49 #include <stdio.h>
  50 #include <arpa/inet.h>
  51
  52 #include "rpcbind.h"
  53
  54 static struct sockaddr_in *local_in4;
  55 #ifdef INET6
  56 static struct sockaddr_in6 *local_in6;
  57 #endif
  58
  59 static int bitmaskcmp(struct sockaddr *, struct sockaddr *, struct sockaddr *);
  60
  61 /*
  62  * For all bits set in "mask", compare the corresponding bits in
  63  * "dst" and "src", and see if they match. Returns 0 if the addresses
  64  * match.
  65  */
  66 static int
  67 bitmaskcmp(struct sockaddr *dst, struct sockaddr *src, struct sockaddr *mask)
  68 {
  69         int i;
  70         u_int8_t *p1, *p2, *netmask;
  71         int bytelen;
  72
  73         if (dst->sa_family != src->sa_family ||
  74             dst->sa_family != mask->sa_family)
  75                 return (1);
  76
  77         switch (dst->sa_family) {
  78         case AF_INET:
  79                 p1 = (uint8_t*) &SA2SINADDR(dst);
  80                 p2 = (uint8_t*) &SA2SINADDR(src);
  81                 netmask = (uint8_t*) &SA2SINADDR(mask);
  82                 bytelen = sizeof(struct in_addr);
  83                 break;
  84 #ifdef INET6
  85         case AF_INET6:
  86                 p1 = (uint8_t*) &SA2SIN6ADDR(dst);
  87                 p2 = (uint8_t*) &SA2SIN6ADDR(src);
  88                 netmask = (uint8_t*) &SA2SIN6ADDR(mask);
  89                 bytelen = sizeof(struct in6_addr);
  90                 break;
  91 #endif
  92         default:
  93                 return (1);
  94         }
  95
  96         for (i = 0; i < bytelen; i++)
  97                 if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
  98                         return (1);
  99         return (0);
 100 }
 101
 102 /*
 103  * Find a server address that can be used by `caller' to contact
 104  * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
 105  * non-NULL, it is used instead of `caller' as a hint suggesting
 106  * the best address (e.g. the `r_addr' field of an rpc, which
 107  * contains the rpcbind server address that the caller used).
 108  *
 109  * Returns the best server address as a malloc'd "universal address"
 110  * string which should be freed by the caller. On error, returns NULL.
 111  */
 112 char *
 113 addrmerge(struct netbuf *caller, const char *serv_uaddr, const char *clnt_uaddr,
 114           const char *netid)
 115 {
 116         struct ifaddrs *ifap, *ifp = NULL, *bestif;
 117         struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
 118         struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
 119         struct sockaddr_storage ss;
 120         struct netconfig *nconf;
 121         char *caller_uaddr = NULL;
 122 #ifdef ND_DEBUG
 123         const char *hint_uaddr = NULL;
 124 #endif
 125         char *ret = NULL;
 126         int bestif_goodness;
 127
 128 #ifdef ND_DEBUG
 129         if (debugging)
 130                 fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
 131                     clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
 132 #endif
 133         caller_sa = caller->buf;
 134         if ((nconf = rpcbind_get_conf(netid)) == NULL)
 135                 goto freeit;
 136         if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
 137                 goto freeit;
 138
 139         /*
 140          * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
 141          * address family is different from that of the caller.
 142          */
 143         hint_sa = NULL;
 144         if (clnt_uaddr != NULL) {
 145 #ifdef ND_DEBUG
 146                 hint_uaddr = clnt_uaddr;
 147 #endif
 148                 if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
 149                         goto freeit;
 150                 hint_sa = hint_nbp->buf;
 151         }
 152         if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
 153 #ifdef ND_DEBUG
 154                 hint_uaddr = caller_uaddr;
 155 #endif
 156                 hint_sa = caller->buf;
 157         }
 158
 159 #ifdef ND_DEBUG
 160         if (debugging)
 161                 fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
 162 #endif
 163         /* Local caller, just return the server address. */
 164         if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
 165             strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
 166                 ret = strdup(serv_uaddr);
 167                 goto freeit;
 168         }
 169
 170         if (getifaddrs(&ifp) < 0)
 171                 goto freeit;
 172
 173         /*
 174          * Loop through all interface addresses.  We are listening to an address
 175          * if any of the following are true:
 176          * a) It's a loopback address
 177          * b) It was specified with the -h command line option
 178          * c) There were no -h command line options.
 179          *
 180          * Among addresses on which we are listening, choose in order of
 181          * preference an address that is:
 182          *
 183          * a) Equal to the hint
 184          * b) A link local address with the same scope ID as the client's
 185          *    address, if the client's address is also link local
 186          * c) An address on the same subnet as the client's address
 187          * d) A non-localhost, non-p2p address
 188          * e) Any usable address
 189          */
 190         bestif = NULL;
 191         bestif_goodness = 0;
 192         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 193                 ifsa = ifap->ifa_addr;
 194                 ifmasksa = ifap->ifa_netmask;
 195
 196                 /* Skip addresses where we don't listen */
 197                 if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
 198                     !(ifap->ifa_flags & IFF_UP))
 199                         continue;
 200
 201                 if (!(ifap->ifa_flags & IFF_LOOPBACK) && !listen_addr(ifsa))
 202                         continue;
 203
 204                 if ((hint_sa->sa_family == AF_INET) &&
 205                     ((((struct sockaddr_in*)hint_sa)->sin_addr.s_addr ==
 206                       ((struct sockaddr_in*)ifsa)->sin_addr.s_addr))) {
 207                         const int goodness = 4;
 208
 209                         bestif_goodness = goodness;
 210                         bestif = ifap;
 211                         goto found;
 212                 }
 213 #ifdef INET6
 214                 if ((hint_sa->sa_family == AF_INET6) &&
 215                     (0 == memcmp(&((struct sockaddr_in6*)hint_sa)->sin6_addr,
 216                                  &((struct sockaddr_in6*)ifsa)->sin6_addr,
 217                                  sizeof(struct in6_addr))) &&
 218                     (((struct sockaddr_in6*)hint_sa)->sin6_scope_id ==
 219                     (((struct sockaddr_in6*)ifsa)->sin6_scope_id))) {
 220                         const int goodness = 4;
 221
 222                         bestif_goodness = goodness;
 223                         bestif = ifap;
 224                         goto found;
 225                 }
 226                 if (hint_sa->sa_family == AF_INET6) {
 227                         /*
 228                          * For v6 link local addresses, if the caller is on
 229                          * a link-local address then use the scope id to see
 230                          * which one.
 231                          */
 232                         if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
 233                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
 234                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
 235                                 if (SA2SIN6(ifsa)->sin6_scope_id ==
 236                                     SA2SIN6(caller_sa)->sin6_scope_id) {
 237                                         const int goodness = 3;
 238
 239                                         if (bestif_goodness < goodness) {
 240                                                 bestif = ifap;
 241                                                 bestif_goodness = goodness;
 242                                         }
 243                                 }
 244                         }
 245                 }
 246 #endif /* INET6 */
 247                 if (0 == bitmaskcmp(hint_sa, ifsa, ifmasksa)) {
 248                         const int goodness = 2;
 249
 250                         if (bestif_goodness < goodness) {
 251                                 bestif = ifap;
 252                                 bestif_goodness = goodness;
 253                         }
 254                 }
 255                 if (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
 256                         const int goodness = 1;
 257
 258                         if (bestif_goodness < goodness) {
 259                                 bestif = ifap;
 260                                 bestif_goodness = goodness;
 261                         }
 262                 }
 263                 if (bestif == NULL)
 264                         bestif = ifap;
 265         }
 266         if (bestif == NULL)
 267                 goto freeit;
 268
 269 found:
 270         /*
 271          * Construct the new address using the address from
 272          * `bestif', and the port number from `serv_uaddr'.
 273          */
 274         serv_nbp = uaddr2taddr(nconf, serv_uaddr);
 275         if (serv_nbp == NULL)
 276                 goto freeit;
 277         serv_sa = serv_nbp->buf;
 278
 279         memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
 280         switch (ss.ss_family) {
 281         case AF_INET:
 282                 SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
 283                 break;
 284 #ifdef INET6
 285         case AF_INET6:
 286                 SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
 287                 break;
 288 #endif
 289         }
 290         tbuf.len = ss.ss_len;
 291         tbuf.maxlen = sizeof(ss);
 292         tbuf.buf = &ss;
 293         ret = taddr2uaddr(nconf, &tbuf);
 294
 295 freeit:
 296         free(caller_uaddr);
 297         if (hint_nbp != NULL) {
 298                 free(hint_nbp->buf);
 299                 free(hint_nbp);
 300         }
 301         if (serv_nbp != NULL) {
 302                 free(serv_nbp->buf);
 303                 free(serv_nbp);
 304         }
 305         if (ifp != NULL)
 306                 freeifaddrs(ifp);
 307
 308 #ifdef ND_DEBUG
 309         if (debugging)
 310                 fprintf(stderr, "addrmerge: returning %s\n", ret);
 311 #endif
 312         return ret;
 313 }
 314
 315 void
 316 network_init(void)
 317 {
 318 #ifdef INET6
 319         struct ifaddrs *ifap, *ifp;
 320         struct ipv6_mreq mreq6;
 321         unsigned int ifindex;
 322         int s;
 323 #endif
 324         int ecode;
 325         struct addrinfo hints, *res;
 326
 327         memset(&hints, 0, sizeof hints);
 328         hints.ai_family = AF_INET;
 329         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 330                 if (debugging)
 331                         fprintf(stderr, "can't get local ip4 address: %s\n",
 332                             gai_strerror(ecode));
 333         } else {
 334                 local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
 335                 if (local_in4 == NULL) {
 336                         if (debugging)
 337                                 fprintf(stderr, "can't alloc local ip4 addr\n");
 338                         exit(1);
 339                 }
 340                 memcpy(local_in4, res->ai_addr, sizeof *local_in4);
 341                 freeaddrinfo(res);
 342         }
 343
 344 #ifdef INET6
 345         hints.ai_family = AF_INET6;
 346         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 347                 if (debugging)
 348                         fprintf(stderr, "can't get local ip6 address: %s\n",
 349                             gai_strerror(ecode));
 350         } else {
 351                 local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
 352                 if (local_in6 == NULL) {
 353                         if (debugging)
 354                                 fprintf(stderr, "can't alloc local ip6 addr\n");
 355                         exit(1);
 356                 }
 357                 memcpy(local_in6, res->ai_addr, sizeof *local_in6);
 358                 freeaddrinfo(res);
 359         }
 360
 361         /*
 362          * Now join the RPC ipv6 multicast group on all interfaces.
 363          */
 364         if (getifaddrs(&ifp) < 0)
 365                 return;
 366
 367         mreq6.ipv6mr_interface = 0;
 368         inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
 369
 370         s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 371         if (s == -1) {
 372                 if (debugging)
 373                         fprintf(stderr, "couldn't create ip6 socket");
 374                 goto done_inet6;
 375         }
 376
 377         /*
 378          * Loop through all interfaces. For each IPv6 multicast-capable
 379          * interface, join the RPC multicast group on that interface.
 380          */
 381         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 382                 if (ifap->ifa_addr->sa_family != AF_INET6 ||
 383                     !(ifap->ifa_flags & IFF_MULTICAST))
 384                         continue;
 385                 ifindex = if_nametoindex(ifap->ifa_name);
 386                 if (ifindex == mreq6.ipv6mr_interface)
 387                         /*
 388                          * Already did this one.
 389                          */
 390                         continue;
 391                 mreq6.ipv6mr_interface = ifindex;
 392                 if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
 393                     sizeof mreq6) < 0)
 394                         if (debugging)
 395                                 perror("setsockopt v6 multicast");
 396         }
 397 done_inet6:
 398         freeifaddrs(ifp);
 399 #endif
 400
 401         /* close(s); */
 402 }
 403
 404 struct sockaddr *
 405 local_sa(int af)
 406 {
 407         switch (af) {
 408         case AF_INET:
 409                 return (struct sockaddr *)local_in4;
 410 #ifdef INET6
 411         case AF_INET6:
 412                 return (struct sockaddr *)local_in6;
 413 #endif
 414         default:
 415                 return NULL;
 416         }
 417 }