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  * 3. All advertising materials mentioning features or use of this software
  22  *    must display the following acknowledgement:
  23  *      This product includes software developed by the NetBSD
  24  *      Foundation, Inc. and its contributors.
  25  * 4. Neither the name of The NetBSD Foundation nor the names of its
  26  *    contributors may be used to endorse or promote products derived
  27  *    from this software without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  30  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  31  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  32  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  33  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  34  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  35  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  36  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  37  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  39  * POSSIBILITY OF SUCH DAMAGE.
  40  */
  41
  42 #include <sys/types.h>
  43 #include <sys/socket.h>
  44 #include <sys/queue.h>
  45 #include <net/if.h>
  46 #include <netinet/in.h>
  47 #include <ifaddrs.h>
  48 #include <sys/poll.h>
  49 #include <rpc/rpc.h>
  50 #include <errno.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include <unistd.h>
  54 #include <netdb.h>
  55 #include <netconfig.h>
  56 #include <stdio.h>
  57 #include <arpa/inet.h>
  58
  59 #include "rpcbind.h"
  60
  61 #define SA2SIN(sa)      ((struct sockaddr_in *)(sa))
  62 #define SA2SINADDR(sa)  (SA2SIN(sa)->sin_addr)
  63 #ifdef INET6
  64 #define SA2SIN6(sa)     ((struct sockaddr_in6 *)(sa))
  65 #define SA2SIN6ADDR(sa) (SA2SIN6(sa)->sin6_addr)
  66 #endif
  67
  68 static struct sockaddr_in *local_in4;
  69 #ifdef INET6
  70 static struct sockaddr_in6 *local_in6;
  71 #endif
  72
  73 static int bitmaskcmp(void *, void *, void *, int);
  74 #ifdef INET6
  75 static void in6_fillscopeid(struct sockaddr_in6 *);
  76 #endif
  77
  78 /*
  79  * For all bits set in "mask", compare the corresponding bits in
  80  * "dst" and "src", and see if they match. Returns 0 if the addresses
  81  * match.
  82  */
  83 static int
  84 bitmaskcmp(void *dst, void *src, void *mask, int bytelen)
  85 {
  86         int i;
  87         u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
  88
  89         for (i = 0; i < bytelen; i++)
  90                 if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
  91                         return (1);
  92         return (0);
  93 }
  94
  95 /*
  96  * Similar to code in ifconfig.c. Fill in the scope ID for link-local
  97  * addresses returned by getifaddrs().
  98  */
  99 #ifdef INET6
 100 static void
 101 in6_fillscopeid(struct sockaddr_in6 *sin6)
 102 {
 103         u_int16_t ifindex;
 104
 105         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 106                 ifindex = ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
 107                 if (sin6->sin6_scope_id == 0 && ifindex != 0) {
 108                         sin6->sin6_scope_id = ifindex;
 109                         *(u_int16_t *)&sin6->sin6_addr.s6_addr[2] = 0;
 110                 }
 111         }
 112 }
 113 #endif
 114
 115 /*
 116  * Find a server address that can be used by `caller' to contact
 117  * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
 118  * non-NULL, it is used instead of `caller' as a hint suggesting
 119  * the best address (e.g. the `r_addr' field of an rpc, which
 120  * contains the rpcbind server address that the caller used).
 121  *
 122  * Returns the best server address as a malloc'd "universal address"
 123  * string which should be freed by the caller. On error, returns NULL.
 124  */
 125 char *
 126 addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
 127           char *netid)
 128 {
 129         struct ifaddrs *ifap, *ifp = NULL, *bestif;
 130         struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
 131         struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
 132         struct sockaddr_storage ss;
 133         struct netconfig *nconf;
 134         char *caller_uaddr = NULL, *hint_uaddr = NULL;
 135         char *ret = NULL;
 136
 137 #ifdef ND_DEBUG
 138         if (debugging)
 139                 fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
 140                     clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
 141 #endif
 142         caller_sa = caller->buf;
 143         if ((nconf = rpcbind_get_conf(netid)) == NULL)
 144                 goto freeit;
 145         if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
 146                 goto freeit;
 147
 148         /*
 149          * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
 150          * address family is different from that of the caller.
 151          */
 152         hint_sa = NULL;
 153         if (clnt_uaddr != NULL) {
 154                 hint_uaddr = clnt_uaddr;
 155                 if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
 156                         goto freeit;
 157                 hint_sa = hint_nbp->buf;
 158         }
 159         if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
 160                 hint_uaddr = caller_uaddr;
 161                 hint_sa = caller->buf;
 162         }
 163
 164 #ifdef ND_DEBUG
 165         if (debugging)
 166                 fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
 167 #endif
 168         /* Local caller, just return the server address. */
 169         if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
 170             strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
 171                 ret = strdup(serv_uaddr);
 172                 goto freeit;
 173         }
 174
 175         if (getifaddrs(&ifp) < 0)
 176                 goto freeit;
 177
 178         /*
 179          * Loop through all interfaces. For each interface, see if the
 180          * network portion of its address is equal to that of the client.
 181          * If so, we have found the interface that we want to use.
 182          */
 183         bestif = NULL;
 184         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 185                 ifsa = ifap->ifa_addr;
 186                 ifmasksa = ifap->ifa_netmask;
 187
 188                 if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
 189                     !(ifap->ifa_flags & IFF_UP))
 190                         continue;
 191
 192                 switch (hint_sa->sa_family) {
 193                 case AF_INET:
 194                         /*
 195                          * If the hint address matches this interface
 196                          * address/netmask, then we're done.
 197                          */
 198                         if (!bitmaskcmp(&SA2SINADDR(ifsa),
 199                             &SA2SINADDR(hint_sa), &SA2SINADDR(ifmasksa),
 200                             sizeof(struct in_addr))) {
 201                                 bestif = ifap;
 202                                 goto found;
 203                         }
 204                         break;
 205 #ifdef INET6
 206                 case AF_INET6:
 207                         /*
 208                          * For v6 link local addresses, if the caller is on
 209                          * a link-local address then use the scope id to see
 210                          * which one.
 211                          */
 212                         in6_fillscopeid(SA2SIN6(ifsa));
 213                         if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
 214                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
 215                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
 216                                 if (SA2SIN6(ifsa)->sin6_scope_id ==
 217                                     SA2SIN6(caller_sa)->sin6_scope_id) {
 218                                         bestif = ifap;
 219                                         goto found;
 220                                 }
 221                         } else if (!bitmaskcmp(&SA2SIN6ADDR(ifsa),
 222                             &SA2SIN6ADDR(hint_sa), &SA2SIN6ADDR(ifmasksa),
 223                             sizeof(struct in6_addr))) {
 224                                 bestif = ifap;
 225                                 goto found;
 226                         }
 227                         break;
 228 #endif
 229                 default:
 230                         continue;
 231                 }
 232
 233                 /*
 234                  * Remember the first possibly useful interface, preferring
 235                  * "normal" to point-to-point and loopback ones.
 236                  */
 237                 if (bestif == NULL ||
 238                     (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) &&
 239                     (bestif->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))))
 240                         bestif = ifap;
 241         }
 242         if (bestif == NULL)
 243                 goto freeit;
 244
 245 found:
 246         /*
 247          * Construct the new address using the the address from
 248          * `bestif', and the port number from `serv_uaddr'.
 249          */
 250         serv_nbp = uaddr2taddr(nconf, serv_uaddr);
 251         if (serv_nbp == NULL)
 252                 goto freeit;
 253         serv_sa = serv_nbp->buf;
 254
 255         memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
 256         switch (ss.ss_family) {
 257         case AF_INET:
 258                 SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
 259                 break;
 260 #ifdef INET6
 261         case AF_INET6:
 262                 SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
 263                 break;
 264 #endif
 265         }
 266         tbuf.len = ss.ss_len;
 267         tbuf.maxlen = sizeof(ss);
 268         tbuf.buf = &ss;
 269         ret = taddr2uaddr(nconf, &tbuf);
 270
 271 freeit:
 272         if (caller_uaddr != NULL)
 273                 free(caller_uaddr);
 274         if (hint_nbp != NULL) {
 275                 free(hint_nbp->buf);
 276                 free(hint_nbp);
 277         }
 278         if (serv_nbp != NULL) {
 279                 free(serv_nbp->buf);
 280                 free(serv_nbp);
 281         }
 282         if (ifp != NULL)
 283                 freeifaddrs(ifp);
 284
 285 #ifdef ND_DEBUG
 286         if (debugging)
 287                 fprintf(stderr, "addrmerge: returning %s\n", ret);
 288 #endif
 289         return ret;
 290 }
 291
 292 void
 293 network_init()
 294 {
 295 #ifdef INET6
 296         struct ifaddrs *ifap, *ifp;
 297         struct ipv6_mreq mreq6;
 298         unsigned int ifindex;
 299         int s;
 300 #endif
 301         int ecode;
 302         struct addrinfo hints, *res;
 303
 304         memset(&hints, 0, sizeof hints);
 305         hints.ai_family = AF_INET;
 306         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 307                 if (debugging)
 308                         fprintf(stderr, "can't get local ip4 address: %s\n",
 309                             gai_strerror(ecode));
 310         } else {
 311                 local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
 312                 if (local_in4 == NULL) {
 313                         if (debugging)
 314                                 fprintf(stderr, "can't alloc local ip4 addr\n");
 315                 }
 316                 memcpy(local_in4, res->ai_addr, sizeof *local_in4);
 317         }
 318
 319 #ifdef INET6
 320         hints.ai_family = AF_INET6;
 321         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 322                 if (debugging)
 323                         fprintf(stderr, "can't get local ip6 address: %s\n",
 324                             gai_strerror(ecode));
 325         } else {
 326                 local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
 327                 if (local_in6 == NULL) {
 328                         if (debugging)
 329                                 fprintf(stderr, "can't alloc local ip6 addr\n");
 330                 }
 331                 memcpy(local_in6, res->ai_addr, sizeof *local_in6);
 332         }
 333
 334         /*
 335          * Now join the RPC ipv6 multicast group on all interfaces.
 336          */
 337         if (getifaddrs(&ifp) < 0)
 338                 return;
 339
 340         mreq6.ipv6mr_interface = 0;
 341         inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
 342
 343         s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 344
 345         /*
 346          * Loop through all interfaces. For each IPv6 multicast-capable
 347          * interface, join the RPC multicast group on that interface.
 348          */
 349         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 350                 if (ifap->ifa_addr->sa_family != AF_INET6 ||
 351                     !(ifap->ifa_flags & IFF_MULTICAST))
 352                         continue;
 353                 ifindex = if_nametoindex(ifap->ifa_name);
 354                 if (ifindex == mreq6.ipv6mr_interface)
 355                         /*
 356                          * Already did this one.
 357                          */
 358                         continue;
 359                 mreq6.ipv6mr_interface = ifindex;
 360                 if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
 361                     sizeof mreq6) < 0)
 362                         if (debugging)
 363                                 perror("setsockopt v6 multicast");
 364         }
 365 #endif
 366
 367         /* close(s); */
 368 }
 369
 370 struct sockaddr *
 371 local_sa(int af)
 372 {
 373         switch (af) {
 374         case AF_INET:
 375                 return (struct sockaddr *)local_in4;
 376 #ifdef INET6
 377         case AF_INET6:
 378                 return (struct sockaddr *)local_in6;
 379 #endif
 380         default:
 381                 return NULL;
 382         }
 383 }