usr.sbin/rpcbind/util.c

   1 /*-
   2  * Copyright (c) 2000 The NetBSD Foundation, Inc.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to The NetBSD Foundation
   6  * by Frank van der Linden.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the NetBSD
  19  *      Foundation, Inc. and its contributors.
  20  * 4. Neither the name of The NetBSD Foundation nor the names of its
  21  *    contributors may be used to endorse or promote products derived
  22  *    from this software without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  28  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  * $NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $
  37  * $FreeBSD: src/usr.sbin/rpcbind/util.c,v 1.6 2007/11/07 10:53:39 kevlo Exp $
  38  */
  39
  40 #include <sys/types.h>
  41 #include <sys/socket.h>
  42 #include <sys/queue.h>
  43 #include <net/if.h>
  44 #include <netinet/in.h>
  45 #include <ifaddrs.h>
  46 #include <sys/poll.h>
  47 #include <rpc/rpc.h>
  48 #include <errno.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52 #include <netdb.h>
  53 #include <netconfig.h>
  54 #include <stdio.h>
  55 #include <arpa/inet.h>
  56
  57 #include "rpcbind.h"
  58
  59 #define SA2SIN(sa)      ((struct sockaddr_in *)(sa))
  60 #define SA2SINADDR(sa)  (SA2SIN(sa)->sin_addr)
  61 #ifdef INET6
  62 #define SA2SIN6(sa)     ((struct sockaddr_in6 *)(sa))
  63 #define SA2SIN6ADDR(sa) (SA2SIN6(sa)->sin6_addr)
  64 #endif
  65
  66 static struct sockaddr_in *local_in4;
  67 #ifdef INET6
  68 static struct sockaddr_in6 *local_in6;
  69 #endif
  70
  71 static int bitmaskcmp(void *, void *, void *, int);
  72 #ifdef INET6
  73 static void in6_fillscopeid(struct sockaddr_in6 *);
  74 #endif
  75
  76 /*
  77  * For all bits set in "mask", compare the corresponding bits in
  78  * "dst" and "src", and see if they match. Returns 0 if the addresses
  79  * match.
  80  */
  81 static int
  82 bitmaskcmp(void *dst, void *src, void *mask, int bytelen)
  83 {
  84         int i;
  85         u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
  86
  87         for (i = 0; i < bytelen; i++)
  88                 if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
  89                         return (1);
  90         return (0);
  91 }
  92
  93 /*
  94  * Similar to code in ifconfig.c. Fill in the scope ID for link-local
  95  * addresses returned by getifaddrs().
  96  */
  97 #ifdef INET6
  98 static void
  99 in6_fillscopeid(struct sockaddr_in6 *sin6)
 100 {
 101         u_int16_t ifindex;
 102
 103         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 104                 ifindex = ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
 105                 if (sin6->sin6_scope_id == 0 && ifindex != 0) {
 106                         sin6->sin6_scope_id = ifindex;
 107                         *(u_int16_t *)&sin6->sin6_addr.s6_addr[2] = 0;
 108                 }
 109         }
 110 }
 111 #endif
 112
 113 /*
 114  * Find a server address that can be used by `caller' to contact
 115  * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
 116  * non-NULL, it is used instead of `caller' as a hint suggesting
 117  * the best address (e.g. the `r_addr' field of an rpc, which
 118  * contains the rpcbind server address that the caller used).
 119  *
 120  * Returns the best server address as a malloc'd "universal address"
 121  * string which should be freed by the caller. On error, returns NULL.
 122  */
 123 char *
 124 addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
 125           char *netid)
 126 {
 127         struct ifaddrs *ifap, *ifp = NULL, *bestif;
 128         struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
 129         struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
 130         struct sockaddr_storage ss;
 131         struct netconfig *nconf;
 132         char *caller_uaddr = NULL, *hint_uaddr = NULL;
 133         char *ret = NULL;
 134
 135 #ifdef ND_DEBUG
 136         if (debugging)
 137                 fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
 138                     clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
 139 #endif
 140         caller_sa = caller->buf;
 141         if ((nconf = rpcbind_get_conf(netid)) == NULL)
 142                 goto freeit;
 143         if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
 144                 goto freeit;
 145
 146         /*
 147          * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
 148          * address family is different from that of the caller.
 149          */
 150         hint_sa = NULL;
 151         if (clnt_uaddr != NULL) {
 152                 hint_uaddr = clnt_uaddr;
 153                 if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
 154                         goto freeit;
 155                 hint_sa = hint_nbp->buf;
 156         }
 157         if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
 158                 hint_uaddr = caller_uaddr;
 159                 hint_sa = caller->buf;
 160         }
 161
 162 #ifdef ND_DEBUG
 163         if (debugging)
 164                 fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
 165 #endif
 166         /* Local caller, just return the server address. */
 167         if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
 168             strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
 169                 ret = strdup(serv_uaddr);
 170                 goto freeit;
 171         }
 172
 173         if (getifaddrs(&ifp) < 0)
 174                 goto freeit;
 175
 176         /*
 177          * Loop through all interfaces. For each interface, see if the
 178          * network portion of its address is equal to that of the client.
 179          * If so, we have found the interface that we want to use.
 180          */
 181         bestif = NULL;
 182         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 183                 ifsa = ifap->ifa_addr;
 184                 ifmasksa = ifap->ifa_netmask;
 185
 186                 if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
 187                     !(ifap->ifa_flags & IFF_UP))
 188                         continue;
 189
 190                 switch (hint_sa->sa_family) {
 191                 case AF_INET:
 192                         /*
 193                          * If the hint address matches this interface
 194                          * address/netmask, then we're done.
 195                          */
 196                         if (!bitmaskcmp(&SA2SINADDR(ifsa),
 197                             &SA2SINADDR(hint_sa), &SA2SINADDR(ifmasksa),
 198                             sizeof(struct in_addr))) {
 199                                 bestif = ifap;
 200                                 goto found;
 201                         }
 202                         break;
 203 #ifdef INET6
 204                 case AF_INET6:
 205                         /*
 206                          * For v6 link local addresses, if the caller is on
 207                          * a link-local address then use the scope id to see
 208                          * which one.
 209                          */
 210                         in6_fillscopeid(SA2SIN6(ifsa));
 211                         if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
 212                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
 213                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
 214                                 if (SA2SIN6(ifsa)->sin6_scope_id ==
 215                                     SA2SIN6(caller_sa)->sin6_scope_id) {
 216                                         bestif = ifap;
 217                                         goto found;
 218                                 }
 219                         } else if (!bitmaskcmp(&SA2SIN6ADDR(ifsa),
 220                             &SA2SIN6ADDR(hint_sa), &SA2SIN6ADDR(ifmasksa),
 221                             sizeof(struct in6_addr))) {
 222                                 bestif = ifap;
 223                                 goto found;
 224                         }
 225                         break;
 226 #endif
 227                 default:
 228                         continue;
 229                 }
 230
 231                 /*
 232                  * Remember the first possibly useful interface, preferring
 233                  * "normal" to point-to-point and loopback ones.
 234                  */
 235                 if (bestif == NULL ||
 236                     (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) &&
 237                     (bestif->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))))
 238                         bestif = ifap;
 239         }
 240         if (bestif == NULL)
 241                 goto freeit;
 242
 243 found:
 244         /*
 245          * Construct the new address using the the address from
 246          * `bestif', and the port number from `serv_uaddr'.
 247          */
 248         serv_nbp = uaddr2taddr(nconf, serv_uaddr);
 249         if (serv_nbp == NULL)
 250                 goto freeit;
 251         serv_sa = serv_nbp->buf;
 252
 253         memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
 254         switch (ss.ss_family) {
 255         case AF_INET:
 256                 SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
 257                 break;
 258 #ifdef INET6
 259         case AF_INET6:
 260                 SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
 261                 break;
 262 #endif
 263         }
 264         tbuf.len = ss.ss_len;
 265         tbuf.maxlen = sizeof(ss);
 266         tbuf.buf = &ss;
 267         ret = taddr2uaddr(nconf, &tbuf);
 268
 269 freeit:
 270         if (caller_uaddr != NULL)
 271                 free(caller_uaddr);
 272         if (hint_nbp != NULL) {
 273                 free(hint_nbp->buf);
 274                 free(hint_nbp);
 275         }
 276         if (serv_nbp != NULL) {
 277                 free(serv_nbp->buf);
 278                 free(serv_nbp);
 279         }
 280         if (ifp != NULL)
 281                 freeifaddrs(ifp);
 282
 283 #ifdef ND_DEBUG
 284         if (debugging)
 285                 fprintf(stderr, "addrmerge: returning %s\n", ret);
 286 #endif
 287         return ret;
 288 }
 289
 290 void
 291 network_init(void)
 292 {
 293 #ifdef INET6
 294         struct ifaddrs *ifap, *ifp;
 295         struct ipv6_mreq mreq6;
 296         unsigned int ifindex;
 297         int s;
 298 #endif
 299         int ecode;
 300         struct addrinfo hints, *res;
 301
 302         memset(&hints, 0, sizeof hints);
 303         hints.ai_family = AF_INET;
 304         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 305                 if (debugging)
 306                         fprintf(stderr, "can't get local ip4 address: %s\n",
 307                             gai_strerror(ecode));
 308         } else {
 309                 local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
 310                 if (local_in4 == NULL) {
 311                         if (debugging)
 312                                 fprintf(stderr, "can't alloc local ip4 addr\n");
 313                 }
 314                 memcpy(local_in4, res->ai_addr, sizeof *local_in4);
 315         }
 316
 317 #ifdef INET6
 318         hints.ai_family = AF_INET6;
 319         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 320                 if (debugging)
 321                         fprintf(stderr, "can't get local ip6 address: %s\n",
 322                             gai_strerror(ecode));
 323         } else {
 324                 local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
 325                 if (local_in6 == NULL) {
 326                         if (debugging)
 327                                 fprintf(stderr, "can't alloc local ip6 addr\n");
 328                 }
 329                 memcpy(local_in6, res->ai_addr, sizeof *local_in6);
 330         }
 331
 332         /*
 333          * Now join the RPC ipv6 multicast group on all interfaces.
 334          */
 335         if (getifaddrs(&ifp) < 0)
 336                 return;
 337
 338         mreq6.ipv6mr_interface = 0;
 339         inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
 340
 341         s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 342
 343         /*
 344          * Loop through all interfaces. For each IPv6 multicast-capable
 345          * interface, join the RPC multicast group on that interface.
 346          */
 347         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 348                 if (ifap->ifa_addr->sa_family != AF_INET6 ||
 349                     !(ifap->ifa_flags & IFF_MULTICAST))
 350                         continue;
 351                 ifindex = if_nametoindex(ifap->ifa_name);
 352                 if (ifindex == mreq6.ipv6mr_interface)
 353                         /*
 354                          * Already did this one.
 355                          */
 356                         continue;
 357                 mreq6.ipv6mr_interface = ifindex;
 358                 if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
 359                     sizeof mreq6) < 0)
 360                         if (debugging)
 361                                 perror("setsockopt v6 multicast");
 362         }
 363 #endif
 364
 365         /* close(s); */
 366 }
 367
 368 struct sockaddr *
 369 local_sa(int af)
 370 {
 371         switch (af) {
 372         case AF_INET:
 373                 return (struct sockaddr *)local_in4;
 374 #ifdef INET6
 375         case AF_INET6:
 376                 return (struct sockaddr *)local_in6;
 377 #endif
 378         default:
 379                 return NULL;
 380         }
 381 }