lib/libnetlink.c

   1 /*
   2  * libnetlink.c RTnetlink service routines.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <stdbool.h>
  16 #include <unistd.h>
  17 #include <fcntl.h>
  18 #include <net/if_arp.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <string.h>
  22 #include <errno.h>
  23 #include <time.h>
  24 #include <sys/uio.h>
  25 #include <linux/fib_rules.h>
  26 #include <linux/if_addrlabel.h>
  27 #include <linux/if_bridge.h>
  28
  29 #include "libnetlink.h"
  30
  31 #define __aligned(x)            __attribute__((aligned(x)))
  32
  33 #ifndef SOL_NETLINK
  34 #define SOL_NETLINK 270
  35 #endif
  36
  37 #ifndef MIN
  38 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  39 #endif
  40
  41 int rcvbuf = 1024 * 1024;
  42
  43 #ifdef HAVE_LIBMNL
  44 #include <libmnl/libmnl.h>
  45
  46 static const enum mnl_attr_data_type extack_policy[NLMSGERR_ATTR_MAX + 1] = {
  47         [NLMSGERR_ATTR_MSG]     = MNL_TYPE_NUL_STRING,
  48         [NLMSGERR_ATTR_OFFS]    = MNL_TYPE_U32,
  49 };
  50
  51 static int err_attr_cb(const struct nlattr *attr, void *data)
  52 {
  53         const struct nlattr **tb = data;
  54         uint16_t type;
  55
  56         if (mnl_attr_type_valid(attr, NLMSGERR_ATTR_MAX) < 0) {
  57                 fprintf(stderr, "Invalid extack attribute\n");
  58                 return MNL_CB_ERROR;
  59         }
  60
  61         type = mnl_attr_get_type(attr);
  62         if (mnl_attr_validate(attr, extack_policy[type]) < 0) {
  63                 fprintf(stderr, "extack attribute %d failed validation\n",
  64                         type);
  65                 return MNL_CB_ERROR;
  66         }
  67
  68         tb[type] = attr;
  69         return MNL_CB_OK;
  70 }
  71
  72 static void print_ext_ack_msg(bool is_err, const char *msg)
  73 {
  74         fprintf(stderr, "%s: %s", is_err ? "Error" : "Warning", msg);
  75         if (msg[strlen(msg) - 1] != '.')
  76                 fprintf(stderr, ".");
  77         fprintf(stderr, "\n");
  78 }
  79
  80 /* dump netlink extended ack error message */
  81 int nl_dump_ext_ack(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn)
  82 {
  83         struct nlattr *tb[NLMSGERR_ATTR_MAX + 1] = {};
  84         const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
  85         const struct nlmsghdr *err_nlh = NULL;
  86         unsigned int hlen = sizeof(*err);
  87         const char *msg = NULL;
  88         uint32_t off = 0;
  89
  90         /* no TLVs, nothing to do here */
  91         if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
  92                 return 0;
  93
  94         /* if NLM_F_CAPPED is set then the inner err msg was capped */
  95         if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
  96                 hlen += mnl_nlmsg_get_payload_len(&err->msg);
  97
  98         if (mnl_attr_parse(nlh, hlen, err_attr_cb, tb) != MNL_CB_OK)
  99                 return 0;
 100
 101         if (tb[NLMSGERR_ATTR_MSG])
 102                 msg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]);
 103
 104         if (tb[NLMSGERR_ATTR_OFFS]) {
 105                 off = mnl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]);
 106
 107                 if (off > nlh->nlmsg_len) {
 108                         fprintf(stderr,
 109                                 "Invalid offset for NLMSGERR_ATTR_OFFS\n");
 110                         off = 0;
 111                 } else if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
 112                         err_nlh = &err->msg;
 113         }
 114
 115         if (errfn)
 116                 return errfn(msg, off, err_nlh);
 117
 118         if (msg && *msg != '\0') {
 119                 bool is_err = !!err->error;
 120
 121                 print_ext_ack_msg(is_err, msg);
 122                 return is_err ? 1 : 0;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static int nl_dump_ext_ack_done(const struct nlmsghdr *nlh, int error)
 129 {
 130         struct nlattr *tb[NLMSGERR_ATTR_MAX + 1] = {};
 131         unsigned int hlen = sizeof(int);
 132         const char *msg = NULL;
 133
 134         if (mnl_attr_parse(nlh, hlen, err_attr_cb, tb) != MNL_CB_OK)
 135                 return 0;
 136
 137         if (tb[NLMSGERR_ATTR_MSG])
 138                 msg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]);
 139
 140         if (msg && *msg != '\0') {
 141                 bool is_err = !!error;
 142
 143                 print_ext_ack_msg(is_err, msg);
 144                 return is_err ? 1 : 0;
 145         }
 146
 147         return 0;
 148 }
 149 #else
 150 #warning "libmnl required for error support"
 151
 152 /* No extended error ack without libmnl */
 153 int nl_dump_ext_ack(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn)
 154 {
 155         return 0;
 156 }
 157
 158 static int nl_dump_ext_ack_done(const struct nlmsghdr *nlh, int error)
 159 {
 160         return 0;
 161 }
 162 #endif
 163
 164 void rtnl_close(struct rtnl_handle *rth)
 165 {
 166         if (rth->fd >= 0) {
 167                 close(rth->fd);
 168                 rth->fd = -1;
 169         }
 170 }
 171
 172 int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions,
 173                       int protocol)
 174 {
 175         socklen_t addr_len;
 176         int sndbuf = 32768;
 177         int one = 1;
 178
 179         memset(rth, 0, sizeof(*rth));
 180
 181         rth->proto = protocol;
 182         rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
 183         if (rth->fd < 0) {
 184                 perror("Cannot open netlink socket");
 185                 return -1;
 186         }
 187
 188         if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF,
 189                        &sndbuf, sizeof(sndbuf)) < 0) {
 190                 perror("SO_SNDBUF");
 191                 return -1;
 192         }
 193
 194         if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF,
 195                        &rcvbuf, sizeof(rcvbuf)) < 0) {
 196                 perror("SO_RCVBUF");
 197                 return -1;
 198         }
 199
 200         /* Older kernels may no support extended ACK reporting */
 201         setsockopt(rth->fd, SOL_NETLINK, NETLINK_EXT_ACK,
 202                    &one, sizeof(one));
 203
 204         memset(&rth->local, 0, sizeof(rth->local));
 205         rth->local.nl_family = AF_NETLINK;
 206         rth->local.nl_groups = subscriptions;
 207
 208         if (bind(rth->fd, (struct sockaddr *)&rth->local,
 209                  sizeof(rth->local)) < 0) {
 210                 perror("Cannot bind netlink socket");
 211                 return -1;
 212         }
 213         addr_len = sizeof(rth->local);
 214         if (getsockname(rth->fd, (struct sockaddr *)&rth->local,
 215                         &addr_len) < 0) {
 216                 perror("Cannot getsockname");
 217                 return -1;
 218         }
 219         if (addr_len != sizeof(rth->local)) {
 220                 fprintf(stderr, "Wrong address length %d\n", addr_len);
 221                 return -1;
 222         }
 223         if (rth->local.nl_family != AF_NETLINK) {
 224                 fprintf(stderr, "Wrong address family %d\n",
 225                         rth->local.nl_family);
 226                 return -1;
 227         }
 228         rth->seq = time(NULL);
 229         return 0;
 230 }
 231
 232 int rtnl_open(struct rtnl_handle *rth, unsigned int subscriptions)
 233 {
 234         return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
 235 }
 236
 237 int rtnl_addrdump_req(struct rtnl_handle *rth, int family)
 238 {
 239         struct {
 240                 struct nlmsghdr nlh;
 241                 struct ifaddrmsg ifm;
 242         } req = {
 243                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
 244                 .nlh.nlmsg_type = RTM_GETADDR,
 245                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 246                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 247                 .ifm.ifa_family = family,
 248         };
 249
 250         return send(rth->fd, &req, sizeof(req), 0);
 251 }
 252
 253 int rtnl_addrlbldump_req(struct rtnl_handle *rth, int family)
 254 {
 255         struct {
 256                 struct nlmsghdr nlh;
 257                 struct ifaddrlblmsg ifal;
 258         } req = {
 259                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrlblmsg)),
 260                 .nlh.nlmsg_type = RTM_GETADDRLABEL,
 261                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 262                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 263                 .ifal.ifal_family = family,
 264         };
 265
 266         return send(rth->fd, &req, sizeof(req), 0);
 267 }
 268
 269 int rtnl_routedump_req(struct rtnl_handle *rth, int family)
 270 {
 271         struct {
 272                 struct nlmsghdr nlh;
 273                 struct rtmsg rtm;
 274         } req = {
 275                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)),
 276                 .nlh.nlmsg_type = RTM_GETROUTE,
 277                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 278                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 279                 .rtm.rtm_family = family,
 280         };
 281
 282         return send(rth->fd, &req, sizeof(req), 0);
 283 }
 284
 285 int rtnl_ruledump_req(struct rtnl_handle *rth, int family)
 286 {
 287         struct {
 288                 struct nlmsghdr nlh;
 289                 struct fib_rule_hdr frh;
 290         } req = {
 291                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct fib_rule_hdr)),
 292                 .nlh.nlmsg_type = RTM_GETRULE,
 293                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 294                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 295                 .frh.family = family
 296         };
 297
 298         return send(rth->fd, &req, sizeof(req), 0);
 299 }
 300
 301 int rtnl_neighdump_req(struct rtnl_handle *rth, int family)
 302 {
 303         struct {
 304                 struct nlmsghdr nlh;
 305                 struct ndmsg ndm;
 306         } req = {
 307                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ndmsg)),
 308                 .nlh.nlmsg_type = RTM_GETNEIGH,
 309                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 310                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 311                 .ndm.ndm_family = family,
 312         };
 313
 314         return send(rth->fd, &req, sizeof(req), 0);
 315 }
 316
 317 int rtnl_neightbldump_req(struct rtnl_handle *rth, int family)
 318 {
 319         struct {
 320                 struct nlmsghdr nlh;
 321                 struct ndtmsg ndtmsg;
 322         } req = {
 323                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ndtmsg)),
 324                 .nlh.nlmsg_type = RTM_GETNEIGHTBL,
 325                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 326                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 327                 .ndtmsg.ndtm_family = family,
 328         };
 329
 330         return send(rth->fd, &req, sizeof(req), 0);
 331 }
 332
 333 int rtnl_mdbdump_req(struct rtnl_handle *rth, int family)
 334 {
 335         struct {
 336                 struct nlmsghdr nlh;
 337                 struct br_port_msg bpm;
 338         } req = {
 339                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct br_port_msg)),
 340                 .nlh.nlmsg_type = RTM_GETMDB,
 341                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 342                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 343                 .bpm.family = family,
 344         };
 345
 346         return send(rth->fd, &req, sizeof(req), 0);
 347 }
 348
 349 int rtnl_netconfdump_req(struct rtnl_handle *rth, int family)
 350 {
 351         struct {
 352                 struct nlmsghdr nlh;
 353                 struct netconfmsg ncm;
 354                 char buf[0] __aligned(NLMSG_ALIGNTO);
 355         } req = {
 356                 .nlh.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct netconfmsg))),
 357                 .nlh.nlmsg_type = RTM_GETNETCONF,
 358                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 359                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 360                 .ncm.ncm_family = family,
 361         };
 362
 363         return send(rth->fd, &req, sizeof(req), 0);
 364 }
 365
 366 int rtnl_nsiddump_req(struct rtnl_handle *rth, int family)
 367 {
 368         struct {
 369                 struct nlmsghdr nlh;
 370                 struct rtgenmsg rtm;
 371                 char buf[0] __aligned(NLMSG_ALIGNTO);
 372         } req = {
 373                 .nlh.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct rtgenmsg))),
 374                 .nlh.nlmsg_type = RTM_GETNSID,
 375                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 376                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 377                 .rtm.rtgen_family = family,
 378         };
 379
 380         return send(rth->fd, &req, sizeof(req), 0);
 381 }
 382
 383 int rtnl_linkdump_req(struct rtnl_handle *rth, int family)
 384 {
 385         return rtnl_linkdump_req_filter(rth, family, RTEXT_FILTER_VF);
 386 }
 387
 388 int rtnl_linkdump_req_filter(struct rtnl_handle *rth, int family,
 389                             __u32 filt_mask)
 390 {
 391         struct {
 392                 struct nlmsghdr nlh;
 393                 struct ifinfomsg ifm;
 394                 /* attribute has to be NLMSG aligned */
 395                 struct rtattr ext_req __aligned(NLMSG_ALIGNTO);
 396                 __u32 ext_filter_mask;
 397         } req = {
 398                 .nlh.nlmsg_len = sizeof(req),
 399                 .nlh.nlmsg_type = RTM_GETLINK,
 400                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 401                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 402                 .ifm.ifi_family = family,
 403                 .ext_req.rta_type = IFLA_EXT_MASK,
 404                 .ext_req.rta_len = RTA_LENGTH(sizeof(__u32)),
 405                 .ext_filter_mask = filt_mask,
 406         };
 407
 408         return send(rth->fd, &req, sizeof(req), 0);
 409 }
 410
 411 int rtnl_linkdump_req_filter_fn(struct rtnl_handle *rth, int family,
 412                                 req_filter_fn_t filter_fn)
 413 {
 414         struct {
 415                 struct nlmsghdr nlh;
 416                 struct ifinfomsg ifm;
 417                 char buf[1024];
 418         } req = {
 419                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
 420                 .nlh.nlmsg_type = RTM_GETLINK,
 421                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 422                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 423                 .ifm.ifi_family = family,
 424         };
 425         int err;
 426
 427         if (!filter_fn)
 428                 return -EINVAL;
 429
 430         err = filter_fn(&req.nlh, sizeof(req));
 431         if (err)
 432                 return err;
 433
 434         return send(rth->fd, &req, req.nlh.nlmsg_len, 0);
 435 }
 436
 437 int rtnl_statsdump_req_filter(struct rtnl_handle *rth, int fam, __u32 filt_mask)
 438 {
 439         struct {
 440                 struct nlmsghdr nlh;
 441                 struct if_stats_msg ifsm;
 442         } req;
 443
 444         memset(&req, 0, sizeof(req));
 445         req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct if_stats_msg));
 446         req.nlh.nlmsg_type = RTM_GETSTATS;
 447         req.nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 448         req.nlh.nlmsg_pid = 0;
 449         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
 450         req.ifsm.family = fam;
 451         req.ifsm.filter_mask = filt_mask;
 452
 453         return send(rth->fd, &req, sizeof(req), 0);
 454 }
 455
 456 int rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
 457 {
 458         return send(rth->fd, buf, len, 0);
 459 }
 460
 461 int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len)
 462 {
 463         struct nlmsghdr *h;
 464         int status;
 465         char resp[1024];
 466
 467         status = send(rth->fd, buf, len, 0);
 468         if (status < 0)
 469                 return status;
 470
 471         /* Check for immediate errors */
 472         status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK);
 473         if (status < 0) {
 474                 if (errno == EAGAIN)
 475                         return 0;
 476                 return -1;
 477         }
 478
 479         for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, status);
 480              h = NLMSG_NEXT(h, status)) {
 481                 if (h->nlmsg_type == NLMSG_ERROR) {
 482                         struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 483
 484                         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
 485                                 fprintf(stderr, "ERROR truncated\n");
 486                         else
 487                                 errno = -err->error;
 488                         return -1;
 489                 }
 490         }
 491
 492         return 0;
 493 }
 494
 495 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 496 {
 497         struct nlmsghdr nlh = {
 498                 .nlmsg_len = NLMSG_LENGTH(len),
 499                 .nlmsg_type = type,
 500                 .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 501                 .nlmsg_seq = rth->dump = ++rth->seq,
 502         };
 503         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 504         struct iovec iov[2] = {
 505                 { .iov_base = &nlh, .iov_len = sizeof(nlh) },
 506                 { .iov_base = req, .iov_len = len }
 507         };
 508         struct msghdr msg = {
 509                 .msg_name = &nladdr,
 510                 .msg_namelen = sizeof(nladdr),
 511                 .msg_iov = iov,
 512                 .msg_iovlen = 2,
 513         };
 514
 515         return sendmsg(rth->fd, &msg, 0);
 516 }
 517
 518 int rtnl_dump_request_n(struct rtnl_handle *rth, struct nlmsghdr *n)
 519 {
 520         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 521         struct iovec iov = {
 522                 .iov_base = n,
 523                 .iov_len = n->nlmsg_len
 524         };
 525         struct msghdr msg = {
 526                 .msg_name = &nladdr,
 527                 .msg_namelen = sizeof(nladdr),
 528                 .msg_iov = &iov,
 529                 .msg_iovlen = 1,
 530         };
 531
 532         n->nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 533         n->nlmsg_pid = 0;
 534         n->nlmsg_seq = rth->dump = ++rth->seq;
 535
 536         return sendmsg(rth->fd, &msg, 0);
 537 }
 538
 539 static int rtnl_dump_done(struct nlmsghdr *h)
 540 {
 541         int len = *(int *)NLMSG_DATA(h);
 542
 543         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) {
 544                 fprintf(stderr, "DONE truncated\n");
 545                 return -1;
 546         }
 547
 548         if (len < 0) {
 549                 /* check for any messages returned from kernel */
 550                 if (nl_dump_ext_ack_done(h, len))
 551                         return len;
 552
 553                 errno = -len;
 554                 switch (errno) {
 555                 case ENOENT:
 556                 case EOPNOTSUPP:
 557                         return -1;
 558                 case EMSGSIZE:
 559                         fprintf(stderr,
 560                                 "Error: Buffer too small for object.\n");
 561                         break;
 562                 default:
 563                         perror("RTNETLINK answers");
 564                 }
 565                 return len;
 566         }
 567
 568         /* check for any messages returned from kernel */
 569         nl_dump_ext_ack(h, NULL);
 570
 571         return 0;
 572 }
 573
 574 static void rtnl_dump_error(const struct rtnl_handle *rth,
 575                             struct nlmsghdr *h)
 576 {
 577
 578         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 579                 fprintf(stderr, "ERROR truncated\n");
 580         } else {
 581                 const struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 582
 583                 errno = -err->error;
 584                 if (rth->proto == NETLINK_SOCK_DIAG &&
 585                     (errno == ENOENT ||
 586                      errno == EOPNOTSUPP))
 587                         return;
 588
 589                 if (!(rth->flags & RTNL_HANDLE_F_SUPPRESS_NLERR))
 590                         perror("RTNETLINK answers");
 591         }
 592 }
 593
 594 static int __rtnl_recvmsg(int fd, struct msghdr *msg, int flags)
 595 {
 596         int len;
 597
 598         do {
 599                 len = recvmsg(fd, msg, flags);
 600         } while (len < 0 && (errno == EINTR || errno == EAGAIN));
 601
 602         if (len < 0) {
 603                 fprintf(stderr, "netlink receive error %s (%d)\n",
 604                         strerror(errno), errno);
 605                 return -errno;
 606         }
 607
 608         if (len == 0) {
 609                 fprintf(stderr, "EOF on netlink\n");
 610                 return -ENODATA;
 611         }
 612
 613         return len;
 614 }
 615
 616 static int rtnl_recvmsg(int fd, struct msghdr *msg, char **answer)
 617 {
 618         struct iovec *iov = msg->msg_iov;
 619         char *buf;
 620         int len;
 621
 622         iov->iov_base = NULL;
 623         iov->iov_len = 0;
 624
 625         len = __rtnl_recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC);
 626         if (len < 0)
 627                 return len;
 628
 629         buf = malloc(len);
 630         if (!buf) {
 631                 fprintf(stderr, "malloc error: not enough buffer\n");
 632                 return -ENOMEM;
 633         }
 634
 635         iov->iov_base = buf;
 636         iov->iov_len = len;
 637
 638         len = __rtnl_recvmsg(fd, msg, 0);
 639         if (len < 0) {
 640                 free(buf);
 641                 return len;
 642         }
 643
 644         if (answer)
 645                 *answer = buf;
 646         else
 647                 free(buf);
 648
 649         return len;
 650 }
 651
 652 static int rtnl_dump_filter_l(struct rtnl_handle *rth,
 653                               const struct rtnl_dump_filter_arg *arg)
 654 {
 655         struct sockaddr_nl nladdr;
 656         struct iovec iov;
 657         struct msghdr msg = {
 658                 .msg_name = &nladdr,
 659                 .msg_namelen = sizeof(nladdr),
 660                 .msg_iov = &iov,
 661                 .msg_iovlen = 1,
 662         };
 663         char *buf;
 664         int dump_intr = 0;
 665
 666         while (1) {
 667                 int status;
 668                 const struct rtnl_dump_filter_arg *a;
 669                 int found_done = 0;
 670                 int msglen = 0;
 671
 672                 status = rtnl_recvmsg(rth->fd, &msg, &buf);
 673                 if (status < 0)
 674                         return status;
 675
 676                 if (rth->dump_fp)
 677                         fwrite(buf, 1, NLMSG_ALIGN(status), rth->dump_fp);
 678
 679                 for (a = arg; a->filter; a++) {
 680                         struct nlmsghdr *h = (struct nlmsghdr *)buf;
 681
 682                         msglen = status;
 683
 684                         while (NLMSG_OK(h, msglen)) {
 685                                 int err = 0;
 686
 687                                 h->nlmsg_flags &= ~a->nc_flags;
 688
 689                                 if (nladdr.nl_pid != 0 ||
 690                                     h->nlmsg_pid != rth->local.nl_pid ||
 691                                     h->nlmsg_seq != rth->dump)
 692                                         goto skip_it;
 693
 694                                 if (h->nlmsg_flags & NLM_F_DUMP_INTR)
 695                                         dump_intr = 1;
 696
 697                                 if (h->nlmsg_type == NLMSG_DONE) {
 698                                         err = rtnl_dump_done(h);
 699                                         if (err < 0) {
 700                                                 free(buf);
 701                                                 return -1;
 702                                         }
 703
 704                                         found_done = 1;
 705                                         break; /* process next filter */
 706                                 }
 707
 708                                 if (h->nlmsg_type == NLMSG_ERROR) {
 709                                         rtnl_dump_error(rth, h);
 710                                         free(buf);
 711                                         return -1;
 712                                 }
 713
 714                                 if (!rth->dump_fp) {
 715                                         err = a->filter(h, a->arg1);
 716                                         if (err < 0) {
 717                                                 free(buf);
 718                                                 return err;
 719                                         }
 720                                 }
 721
 722 skip_it:
 723                                 h = NLMSG_NEXT(h, msglen);
 724                         }
 725                 }
 726                 free(buf);
 727
 728                 if (found_done) {
 729                         if (dump_intr)
 730                                 fprintf(stderr,
 731                                         "Dump was interrupted and may be inconsistent.\n");
 732                         return 0;
 733                 }
 734
 735                 if (msg.msg_flags & MSG_TRUNC) {
 736                         fprintf(stderr, "Message truncated\n");
 737                         continue;
 738                 }
 739                 if (msglen) {
 740                         fprintf(stderr, "!!!Remnant of size %d\n", msglen);
 741                         exit(1);
 742                 }
 743         }
 744 }
 745
 746 int rtnl_dump_filter_nc(struct rtnl_handle *rth,
 747                      rtnl_filter_t filter,
 748                      void *arg1, __u16 nc_flags)
 749 {
 750         const struct rtnl_dump_filter_arg a[2] = {
 751                 { .filter = filter, .arg1 = arg1, .nc_flags = nc_flags, },
 752                 { .filter = NULL,   .arg1 = NULL, .nc_flags = 0, },
 753         };
 754
 755         return rtnl_dump_filter_l(rth, a);
 756 }
 757
 758 static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err,
 759                             nl_ext_ack_fn_t errfn)
 760 {
 761         if (nl_dump_ext_ack(h, errfn))
 762                 return;
 763
 764         fprintf(stderr, "RTNETLINK answers: %s\n",
 765                 strerror(-err->error));
 766 }
 767
 768
 769 static int __rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iov,
 770                            size_t iovlen, struct nlmsghdr **answer,
 771                            bool show_rtnl_err, nl_ext_ack_fn_t errfn)
 772 {
 773         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 774         struct iovec riov;
 775         struct msghdr msg = {
 776                 .msg_name = &nladdr,
 777                 .msg_namelen = sizeof(nladdr),
 778                 .msg_iov = iov,
 779                 .msg_iovlen = iovlen,
 780         };
 781         unsigned int seq = 0;
 782         struct nlmsghdr *h;
 783         int i, status;
 784         char *buf;
 785
 786         for (i = 0; i < iovlen; i++) {
 787                 h = iov[i].iov_base;
 788                 h->nlmsg_seq = seq = ++rtnl->seq;
 789                 if (answer == NULL)
 790                         h->nlmsg_flags |= NLM_F_ACK;
 791         }
 792
 793         status = sendmsg(rtnl->fd, &msg, 0);
 794         if (status < 0) {
 795                 perror("Cannot talk to rtnetlink");
 796                 return -1;
 797         }
 798
 799         /* change msg to use the response iov */
 800         msg.msg_iov = &riov;
 801         msg.msg_iovlen = 1;
 802         i = 0;
 803         while (1) {
 804 next:
 805                 status = rtnl_recvmsg(rtnl->fd, &msg, &buf);
 806                 ++i;
 807
 808                 if (status < 0)
 809                         return status;
 810
 811                 if (msg.msg_namelen != sizeof(nladdr)) {
 812                         fprintf(stderr,
 813                                 "sender address length == %d\n",
 814                                 msg.msg_namelen);
 815                         exit(1);
 816                 }
 817                 for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
 818                         int len = h->nlmsg_len;
 819                         int l = len - sizeof(*h);
 820
 821                         if (l < 0 || len > status) {
 822                                 if (msg.msg_flags & MSG_TRUNC) {
 823                                         fprintf(stderr, "Truncated message\n");
 824                                         free(buf);
 825                                         return -1;
 826                                 }
 827                                 fprintf(stderr,
 828                                         "!!!malformed message: len=%d\n",
 829                                         len);
 830                                 exit(1);
 831                         }
 832
 833                         if (nladdr.nl_pid != 0 ||
 834                             h->nlmsg_pid != rtnl->local.nl_pid ||
 835                             h->nlmsg_seq > seq || h->nlmsg_seq < seq - iovlen) {
 836                                 /* Don't forget to skip that message. */
 837                                 status -= NLMSG_ALIGN(len);
 838                                 h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 839                                 continue;
 840                         }
 841
 842                         if (h->nlmsg_type == NLMSG_ERROR) {
 843                                 struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 844                                 int error = err->error;
 845
 846                                 if (l < sizeof(struct nlmsgerr)) {
 847                                         fprintf(stderr, "ERROR truncated\n");
 848                                         free(buf);
 849                                         return -1;
 850                                 }
 851
 852                                 if (!error) {
 853                                         /* check messages from kernel */
 854                                         nl_dump_ext_ack(h, errfn);
 855                                 } else {
 856                                         errno = -error;
 857
 858                                         if (rtnl->proto != NETLINK_SOCK_DIAG &&
 859                                             show_rtnl_err)
 860                                                 rtnl_talk_error(h, err, errfn);
 861                                 }
 862
 863                                 if (answer)
 864                                         *answer = (struct nlmsghdr *)buf;
 865                                 else
 866                                         free(buf);
 867
 868                                 if (i < iovlen)
 869                                         goto next;
 870                                 return error ? -i : 0;
 871                         }
 872
 873                         if (answer) {
 874                                 *answer = (struct nlmsghdr *)buf;
 875                                 return 0;
 876                         }
 877
 878                         fprintf(stderr, "Unexpected reply!!!\n");
 879
 880                         status -= NLMSG_ALIGN(len);
 881                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 882                 }
 883                 free(buf);
 884
 885                 if (msg.msg_flags & MSG_TRUNC) {
 886                         fprintf(stderr, "Message truncated\n");
 887                         continue;
 888                 }
 889
 890                 if (status) {
 891                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 892                         exit(1);
 893                 }
 894         }
 895 }
 896
 897 static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 898                        struct nlmsghdr **answer,
 899                        bool show_rtnl_err, nl_ext_ack_fn_t errfn)
 900 {
 901         struct iovec iov = {
 902                 .iov_base = n,
 903                 .iov_len = n->nlmsg_len
 904         };
 905
 906         return __rtnl_talk_iov(rtnl, &iov, 1, answer, show_rtnl_err, errfn);
 907 }
 908
 909 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 910               struct nlmsghdr **answer)
 911 {
 912         return __rtnl_talk(rtnl, n, answer, true, NULL);
 913 }
 914
 915 int rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iovec, size_t iovlen,
 916                   struct nlmsghdr **answer)
 917 {
 918         return __rtnl_talk_iov(rtnl, iovec, iovlen, answer, true, NULL);
 919 }
 920
 921 int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 922                                    struct nlmsghdr **answer)
 923 {
 924         return __rtnl_talk(rtnl, n, answer, false, NULL);
 925 }
 926
 927 int rtnl_listen_all_nsid(struct rtnl_handle *rth)
 928 {
 929         unsigned int on = 1;
 930
 931         if (setsockopt(rth->fd, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, &on,
 932                        sizeof(on)) < 0) {
 933                 perror("NETLINK_LISTEN_ALL_NSID");
 934                 return -1;
 935         }
 936         rth->flags |= RTNL_HANDLE_F_LISTEN_ALL_NSID;
 937         return 0;
 938 }
 939
 940 int rtnl_listen(struct rtnl_handle *rtnl,
 941                 rtnl_listen_filter_t handler,
 942                 void *jarg)
 943 {
 944         int status;
 945         struct nlmsghdr *h;
 946         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 947         struct iovec iov;
 948         struct msghdr msg = {
 949                 .msg_name = &nladdr,
 950                 .msg_namelen = sizeof(nladdr),
 951                 .msg_iov = &iov,
 952                 .msg_iovlen = 1,
 953         };
 954         char   buf[16384];
 955         char   cmsgbuf[BUFSIZ];
 956
 957         if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
 958                 msg.msg_control = &cmsgbuf;
 959                 msg.msg_controllen = sizeof(cmsgbuf);
 960         }
 961
 962         iov.iov_base = buf;
 963         while (1) {
 964                 struct rtnl_ctrl_data ctrl;
 965                 struct cmsghdr *cmsg;
 966
 967                 iov.iov_len = sizeof(buf);
 968                 status = recvmsg(rtnl->fd, &msg, 0);
 969
 970                 if (status < 0) {
 971                         if (errno == EINTR || errno == EAGAIN)
 972                                 continue;
 973                         fprintf(stderr, "netlink receive error %s (%d)\n",
 974                                 strerror(errno), errno);
 975                         if (errno == ENOBUFS)
 976                                 continue;
 977                         return -1;
 978                 }
 979                 if (status == 0) {
 980                         fprintf(stderr, "EOF on netlink\n");
 981                         return -1;
 982                 }
 983                 if (msg.msg_namelen != sizeof(nladdr)) {
 984                         fprintf(stderr,
 985                                 "Sender address length == %d\n",
 986                                 msg.msg_namelen);
 987                         exit(1);
 988                 }
 989
 990                 if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
 991                         memset(&ctrl, 0, sizeof(ctrl));
 992                         ctrl.nsid = -1;
 993                         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg;
 994                              cmsg = CMSG_NXTHDR(&msg, cmsg))
 995                                 if (cmsg->cmsg_level == SOL_NETLINK &&
 996                                     cmsg->cmsg_type == NETLINK_LISTEN_ALL_NSID &&
 997                                     cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
 998                                         int *data = (int *)CMSG_DATA(cmsg);
 999
1000                                         ctrl.nsid = *data;
1001                                 }
1002                 }
1003
1004                 for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
1005                         int err;
1006                         int len = h->nlmsg_len;
1007                         int l = len - sizeof(*h);
1008
1009                         if (l < 0 || len > status) {
1010                                 if (msg.msg_flags & MSG_TRUNC) {
1011                                         fprintf(stderr, "Truncated message\n");
1012                                         return -1;
1013                                 }
1014                                 fprintf(stderr,
1015                                         "!!!malformed message: len=%d\n",
1016                                         len);
1017                                 exit(1);
1018                         }
1019
1020                         err = handler(&ctrl, h, jarg);
1021                         if (err < 0)
1022                                 return err;
1023
1024                         status -= NLMSG_ALIGN(len);
1025                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
1026                 }
1027                 if (msg.msg_flags & MSG_TRUNC) {
1028                         fprintf(stderr, "Message truncated\n");
1029                         continue;
1030                 }
1031                 if (status) {
1032                         fprintf(stderr, "!!!Remnant of size %d\n", status);
1033                         exit(1);
1034                 }
1035         }
1036 }
1037
1038 int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler,
1039                    void *jarg)
1040 {
1041         int status;
1042         char buf[16384];
1043         struct nlmsghdr *h = (struct nlmsghdr *)buf;
1044
1045         while (1) {
1046                 int err, len;
1047                 int l;
1048
1049                 status = fread(&buf, 1, sizeof(*h), rtnl);
1050
1051                 if (status < 0) {
1052                         if (errno == EINTR)
1053                                 continue;
1054                         perror("rtnl_from_file: fread");
1055                         return -1;
1056                 }
1057                 if (status == 0)
1058                         return 0;
1059
1060                 len = h->nlmsg_len;
1061                 l = len - sizeof(*h);
1062
1063                 if (l < 0 || len > sizeof(buf)) {
1064                         fprintf(stderr, "!!!malformed message: len=%d @%lu\n",
1065                                 len, ftell(rtnl));
1066                         return -1;
1067                 }
1068
1069                 status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);
1070
1071                 if (status < 0) {
1072                         perror("rtnl_from_file: fread");
1073                         return -1;
1074                 }
1075                 if (status < l) {
1076                         fprintf(stderr, "rtnl-from_file: truncated message\n");
1077                         return -1;
1078                 }
1079
1080                 err = handler(NULL, h, jarg);
1081                 if (err < 0)
1082                         return err;
1083         }
1084 }
1085
1086 int addattr(struct nlmsghdr *n, int maxlen, int type)
1087 {
1088         return addattr_l(n, maxlen, type, NULL, 0);
1089 }
1090
1091 int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data)
1092 {
1093         return addattr_l(n, maxlen, type, &data, sizeof(__u8));
1094 }
1095
1096 int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data)
1097 {
1098         return addattr_l(n, maxlen, type, &data, sizeof(__u16));
1099 }
1100
1101 int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
1102 {
1103         return addattr_l(n, maxlen, type, &data, sizeof(__u32));
1104 }
1105
1106 int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data)
1107 {
1108         return addattr_l(n, maxlen, type, &data, sizeof(__u64));
1109 }
1110
1111 int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *str)
1112 {
1113         return addattr_l(n, maxlen, type, str, strlen(str)+1);
1114 }
1115
1116 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
1117               int alen)
1118 {
1119         int len = RTA_LENGTH(alen);
1120         struct rtattr *rta;
1121
1122         if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
1123                 fprintf(stderr,
1124                         "addattr_l ERROR: message exceeded bound of %d\n",
1125                         maxlen);
1126                 return -1;
1127         }
1128         rta = NLMSG_TAIL(n);
1129         rta->rta_type = type;
1130         rta->rta_len = len;
1131         if (alen)
1132                 memcpy(RTA_DATA(rta), data, alen);
1133         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
1134         return 0;
1135 }
1136
1137 int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
1138 {
1139         if (NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len) > maxlen) {
1140                 fprintf(stderr,
1141                         "addraw_l ERROR: message exceeded bound of %d\n",
1142                         maxlen);
1143                 return -1;
1144         }
1145
1146         memcpy(NLMSG_TAIL(n), data, len);
1147         memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
1148         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
1149         return 0;
1150 }
1151
1152 struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
1153 {
1154         struct rtattr *nest = NLMSG_TAIL(n);
1155
1156         addattr_l(n, maxlen, type, NULL, 0);
1157         return nest;
1158 }
1159
1160 int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
1161 {
1162         nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest;
1163         return n->nlmsg_len;
1164 }
1165
1166 struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
1167                                    const void *data, int len)
1168 {
1169         struct rtattr *start = NLMSG_TAIL(n);
1170
1171         addattr_l(n, maxlen, type, data, len);
1172         addattr_nest(n, maxlen, type);
1173         return start;
1174 }
1175
1176 int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
1177 {
1178         struct rtattr *nest = (void *)start + NLMSG_ALIGN(start->rta_len);
1179
1180         start->rta_len = (void *)NLMSG_TAIL(n) - (void *)start;
1181         addattr_nest_end(n, nest);
1182         return n->nlmsg_len;
1183 }
1184
1185 int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
1186 {
1187         int len = RTA_LENGTH(4);
1188         struct rtattr *subrta;
1189
1190         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
1191                 fprintf(stderr,
1192                         "rta_addattr32: Error! max allowed bound %d exceeded\n",
1193                         maxlen);
1194                 return -1;
1195         }
1196         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
1197         subrta->rta_type = type;
1198         subrta->rta_len = len;
1199         memcpy(RTA_DATA(subrta), &data, 4);
1200         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
1201         return 0;
1202 }
1203
1204 int rta_addattr_l(struct rtattr *rta, int maxlen, int type,
1205                   const void *data, int alen)
1206 {
1207         struct rtattr *subrta;
1208         int len = RTA_LENGTH(alen);
1209
1210         if (RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len) > maxlen) {
1211                 fprintf(stderr,
1212                         "rta_addattr_l: Error! max allowed bound %d exceeded\n",
1213                         maxlen);
1214                 return -1;
1215         }
1216         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
1217         subrta->rta_type = type;
1218         subrta->rta_len = len;
1219         if (alen)
1220                 memcpy(RTA_DATA(subrta), data, alen);
1221         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
1222         return 0;
1223 }
1224
1225 int rta_addattr8(struct rtattr *rta, int maxlen, int type, __u8 data)
1226 {
1227         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u8));
1228 }
1229
1230 int rta_addattr16(struct rtattr *rta, int maxlen, int type, __u16 data)
1231 {
1232         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u16));
1233 }
1234
1235 int rta_addattr64(struct rtattr *rta, int maxlen, int type, __u64 data)
1236 {
1237         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u64));
1238 }
1239
1240 struct rtattr *rta_nest(struct rtattr *rta, int maxlen, int type)
1241 {
1242         struct rtattr *nest = RTA_TAIL(rta);
1243
1244         rta_addattr_l(rta, maxlen, type, NULL, 0);
1245
1246         return nest;
1247 }
1248
1249 int rta_nest_end(struct rtattr *rta, struct rtattr *nest)
1250 {
1251         nest->rta_len = (void *)RTA_TAIL(rta) - (void *)nest;
1252
1253         return rta->rta_len;
1254 }
1255
1256 int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
1257 {
1258         return parse_rtattr_flags(tb, max, rta, len, 0);
1259 }
1260
1261 int parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
1262                        int len, unsigned short flags)
1263 {
1264         unsigned short type;
1265
1266         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
1267         while (RTA_OK(rta, len)) {
1268                 type = rta->rta_type & ~flags;
1269                 if ((type <= max) && (!tb[type]))
1270                         tb[type] = rta;
1271                 rta = RTA_NEXT(rta, len);
1272         }
1273         if (len)
1274                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1275                         len, rta->rta_len);
1276         return 0;
1277 }
1278
1279 struct rtattr *parse_rtattr_one(int type, struct rtattr *rta, int len)
1280 {
1281         while (RTA_OK(rta, len)) {
1282                 if (rta->rta_type == type)
1283                         return rta;
1284                 rta = RTA_NEXT(rta, len);
1285         }
1286
1287         if (len)
1288                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1289                         len, rta->rta_len);
1290         return NULL;
1291 }
1292
1293 int __parse_rtattr_nested_compat(struct rtattr *tb[], int max,
1294                                  struct rtattr *rta,
1295                                  int len)
1296 {
1297         if (RTA_PAYLOAD(rta) < len)
1298                 return -1;
1299         if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
1300                 rta = RTA_DATA(rta) + RTA_ALIGN(len);
1301                 return parse_rtattr_nested(tb, max, rta);
1302         }
1303         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
1304         return 0;
1305 }