pimd/mtracebis_netlink.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * libnetlink.c RTnetlink service routines.
   4  *
   5  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  *
   7  */
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include "config.h"
  11 #endif
  12
  13 #ifdef __linux__
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <unistd.h>
  18 #include <syslog.h>
  19 #include <fcntl.h>
  20 #include <net/if_arp.h>
  21 #include <sys/socket.h>
  22 #include <netinet/in.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <time.h>
  26 #include <sys/uio.h>
  27 #include <assert.h>
  28
  29 #include "mtracebis_netlink.h"
  30
  31 int rcvbuf = 1024 * 1024;
  32
  33 void rtnl_close(struct rtnl_handle *rth)
  34 {
  35         if (rth->fd >= 0) {
  36                 close(rth->fd);
  37                 rth->fd = -1;
  38         }
  39 }
  40
  41 int rtnl_open_byproto(struct rtnl_handle *rth, unsigned subscriptions,
  42                       int protocol)
  43 {
  44         socklen_t addr_len;
  45         int sndbuf = 32768;
  46
  47         memset(rth, 0, sizeof(*rth));
  48
  49         rth->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
  50         if (rth->fd < 0) {
  51                 perror("Cannot open netlink socket");
  52                 return -1;
  53         }
  54
  55         if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf))
  56             < 0) {
  57                 perror("SO_SNDBUF");
  58                 return -1;
  59         }
  60
  61         if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf))
  62             < 0) {
  63                 perror("SO_RCVBUF");
  64                 return -1;
  65         }
  66
  67         memset(&rth->local, 0, sizeof(rth->local));
  68         rth->local.nl_family = AF_NETLINK;
  69         rth->local.nl_groups = subscriptions;
  70
  71         if (bind(rth->fd, (struct sockaddr *)&rth->local, sizeof(rth->local))
  72             < 0) {
  73                 perror("Cannot bind netlink socket");
  74                 return -1;
  75         }
  76         addr_len = sizeof(rth->local);
  77         if (getsockname(rth->fd, (struct sockaddr *)&rth->local, &addr_len)
  78             < 0) {
  79                 perror("Cannot getsockname");
  80                 return -1;
  81         }
  82         if (addr_len != sizeof(rth->local)) {
  83                 fprintf(stderr, "Wrong address length %d\n", addr_len);
  84                 return -1;
  85         }
  86         if (rth->local.nl_family != AF_NETLINK) {
  87                 fprintf(stderr, "Wrong address family %d\n",
  88                         rth->local.nl_family);
  89                 return -1;
  90         }
  91         rth->seq = getpid();
  92         return 0;
  93 }
  94
  95 int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
  96 {
  97         return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
  98 }
  99
 100 int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
 101 {
 102         struct {
 103                 struct nlmsghdr nlh;
 104                 struct rtgenmsg g;
 105         } req;
 106
 107         memset(&req, 0, sizeof(req));
 108         req.nlh.nlmsg_len = sizeof(req);
 109         req.nlh.nlmsg_type = type;
 110         req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
 111         req.nlh.nlmsg_pid = 0;
 112         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
 113         req.g.rtgen_family = family;
 114
 115         return send(rth->fd, (void *)&req, sizeof(req), 0);
 116 }
 117
 118 int rtnl_send(struct rtnl_handle *rth, const char *buf, int len)
 119 {
 120         return send(rth->fd, buf, len, 0);
 121 }
 122
 123 int rtnl_send_check(struct rtnl_handle *rth, const char *buf, int len)
 124 {
 125         struct nlmsghdr *h;
 126         int status;
 127         char resp[1024];
 128
 129         status = send(rth->fd, buf, len, 0);
 130         if (status < 0)
 131                 return status;
 132
 133         /* Check for immediate errors */
 134         status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT | MSG_PEEK);
 135         if (status < 0) {
 136                 if (errno == EAGAIN)
 137                         return 0;
 138                 return -1;
 139         }
 140
 141         for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, (uint32_t)status);
 142              h = NLMSG_NEXT(h, status)) {
 143                 if (h->nlmsg_type == NLMSG_ERROR) {
 144                         struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 145                         if (h->nlmsg_len
 146                             < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
 147                                 fprintf(stderr, "ERROR truncated\n");
 148                         else
 149                                 errno = -err->error;
 150                         return -1;
 151                 }
 152         }
 153
 154         return 0;
 155 }
 156
 157 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 158 {
 159         struct nlmsghdr nlh;
 160         struct sockaddr_nl nladdr;
 161         struct iovec iov[2] = {{.iov_base = &nlh, .iov_len = sizeof(nlh)},
 162                                {.iov_base = req, .iov_len = len}};
 163         struct msghdr msg = {
 164                 .msg_name = &nladdr,
 165                 .msg_namelen = sizeof(nladdr),
 166                 .msg_iov = iov,
 167                 .msg_iovlen = 2,
 168         };
 169
 170         memset(&nladdr, 0, sizeof(nladdr));
 171         nladdr.nl_family = AF_NETLINK;
 172
 173         nlh.nlmsg_len = NLMSG_LENGTH(len);
 174         nlh.nlmsg_type = type;
 175         nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
 176         nlh.nlmsg_pid = 0;
 177         nlh.nlmsg_seq = rth->dump = ++rth->seq;
 178
 179         return sendmsg(rth->fd, &msg, 0);
 180 }
 181
 182 int rtnl_dump_filter_l(struct rtnl_handle *rth,
 183                        const struct rtnl_dump_filter_arg *arg)
 184 {
 185         struct sockaddr_nl nladdr;
 186         char buf[16384];
 187         struct iovec iov = {
 188                 .iov_base = buf,
 189                 .iov_len = sizeof(buf),
 190         };
 191         struct msghdr msg = {
 192                 .msg_name = &nladdr,
 193                 .msg_namelen = sizeof(nladdr),
 194                 .msg_iov = &iov,
 195                 .msg_iovlen = 1,
 196         };
 197
 198         while (1) {
 199                 int status;
 200                 const struct rtnl_dump_filter_arg *a;
 201                 int found_done = 0;
 202                 int msglen = 0;
 203
 204                 iov.iov_len = sizeof(buf);
 205                 status = recvmsg(rth->fd, &msg, 0);
 206
 207                 if (status < 0) {
 208                         if (errno == EINTR || errno == EAGAIN)
 209                                 continue;
 210                         fprintf(stderr, "netlink receive error %s (%d)\n",
 211                                 strerror(errno), errno);
 212                         return -1;
 213                 }
 214
 215                 if (status == 0) {
 216                         fprintf(stderr, "EOF on netlink\n");
 217                         return -1;
 218                 }
 219
 220                 for (a = arg; a->filter; a++) {
 221                         struct nlmsghdr *h = (struct nlmsghdr *)iov.iov_base;
 222                         msglen = status;
 223
 224                         while (NLMSG_OK(h, (uint32_t)msglen)) {
 225                                 int err;
 226
 227                                 if (nladdr.nl_pid != 0
 228                                     || h->nlmsg_pid != rth->local.nl_pid
 229                                     || h->nlmsg_seq != rth->dump) {
 230                                         if (a->junk) {
 231                                                 err = a->junk(&nladdr, h,
 232                                                               a->arg2);
 233                                                 if (err < 0)
 234                                                         return err;
 235                                         }
 236                                         goto skip_it;
 237                                 }
 238
 239                                 if (h->nlmsg_type == NLMSG_DONE) {
 240                                         found_done = 1;
 241                                         break; /* process next filter */
 242                                 }
 243                                 if (h->nlmsg_type == NLMSG_ERROR) {
 244                                         struct nlmsgerr *merr =
 245                                                 (struct nlmsgerr *)NLMSG_DATA(
 246                                                         h);
 247                                         if (h->nlmsg_len
 248                                             < NLMSG_LENGTH(sizeof(
 249                                                       struct nlmsgerr))) {
 250                                                 fprintf(stderr,
 251                                                         "ERROR truncated\n");
 252                                         } else {
 253                                                 errno = -merr->error;
 254                                                 perror("RTNETLINK answers");
 255                                         }
 256                                         return -1;
 257                                 }
 258                                 err = a->filter(&nladdr, h, a->arg1);
 259                                 if (err < 0)
 260                                         return err;
 261
 262                         skip_it:
 263                                 h = NLMSG_NEXT(h, msglen);
 264                         }
 265                 }
 266
 267                 if (found_done)
 268                         return 0;
 269
 270                 if (msg.msg_flags & MSG_TRUNC) {
 271                         fprintf(stderr, "Message truncated\n");
 272                         continue;
 273                 }
 274                 if (msglen) {
 275                         fprintf(stderr, "!!!Remnant of size %d\n", msglen);
 276                         exit(1);
 277                 }
 278         }
 279 }
 280
 281 int rtnl_dump_filter(struct rtnl_handle *rth, rtnl_filter_t filter, void *arg1,
 282                      rtnl_filter_t junk, void *arg2)
 283 {
 284         const struct rtnl_dump_filter_arg a[2] = {
 285                 {.filter = filter, .arg1 = arg1, .junk = junk, .arg2 = arg2},
 286                 {.filter = NULL, .arg1 = NULL, .junk = NULL, .arg2 = NULL}};
 287
 288         return rtnl_dump_filter_l(rth, a);
 289 }
 290
 291 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
 292               unsigned groups, struct nlmsghdr *answer, rtnl_filter_t junk,
 293               void *jarg)
 294 {
 295         int status;
 296         unsigned seq;
 297         struct nlmsghdr *h;
 298         struct sockaddr_nl nladdr;
 299         struct iovec iov = {.iov_base = (void *)n, .iov_len = n->nlmsg_len};
 300         struct msghdr msg = {
 301                 .msg_name = &nladdr,
 302                 .msg_namelen = sizeof(nladdr),
 303                 .msg_iov = &iov,
 304                 .msg_iovlen = 1,
 305         };
 306         char buf[16384];
 307
 308         memset(&nladdr, 0, sizeof(nladdr));
 309         nladdr.nl_family = AF_NETLINK;
 310         nladdr.nl_pid = peer;
 311         nladdr.nl_groups = groups;
 312
 313         n->nlmsg_seq = seq = ++rtnl->seq;
 314
 315         if (answer == NULL)
 316                 n->nlmsg_flags |= NLM_F_ACK;
 317
 318         status = sendmsg(rtnl->fd, &msg, 0);
 319
 320         if (status < 0) {
 321                 perror("Cannot talk to rtnetlink");
 322                 return -1;
 323         }
 324
 325         memset(buf, 0, sizeof(buf));
 326
 327         iov.iov_base = buf;
 328
 329         while (1) {
 330                 iov.iov_len = sizeof(buf);
 331                 status = recvmsg(rtnl->fd, &msg, 0);
 332
 333                 if (status < 0) {
 334                         if (errno == EINTR || errno == EAGAIN)
 335                                 continue;
 336                         fprintf(stderr, "netlink receive error %s (%d)\n",
 337                                 strerror(errno), errno);
 338                         return -1;
 339                 }
 340                 if (status == 0) {
 341                         fprintf(stderr, "EOF on netlink\n");
 342                         return -1;
 343                 }
 344                 if (msg.msg_namelen != sizeof(nladdr)) {
 345                         fprintf(stderr, "sender address length == %d\n",
 346                                 msg.msg_namelen);
 347                         exit(1);
 348                 }
 349                 for (h = (struct nlmsghdr *)iov.iov_base;
 350                      status >= (int)sizeof(*h);) {
 351                         int err;
 352                         int len = h->nlmsg_len;
 353                         int l = len - sizeof(*h);
 354
 355                         if (l < 0 || len > status) {
 356                                 if (msg.msg_flags & MSG_TRUNC) {
 357                                         fprintf(stderr, "Truncated message\n");
 358                                         return -1;
 359                                 }
 360                                 fprintf(stderr,
 361                                         "!!!malformed message: len=%d\n", len);
 362                                 exit(1);
 363                         }
 364
 365                         if ((int)nladdr.nl_pid != peer
 366                             || h->nlmsg_pid != rtnl->local.nl_pid
 367                             || h->nlmsg_seq != seq) {
 368                                 if (junk) {
 369                                         err = junk(&nladdr, h, jarg);
 370                                         if (err < 0)
 371                                                 return err;
 372                                 }
 373                                 /* Don't forget to skip that message. */
 374                                 status -= NLMSG_ALIGN(len);
 375                                 h = (struct nlmsghdr *)((char *)h
 376                                                         + NLMSG_ALIGN(len));
 377                                 continue;
 378                         }
 379
 380                         if (h->nlmsg_type == NLMSG_ERROR) {
 381                                 struct nlmsgerr *merr =
 382                                         (struct nlmsgerr *)NLMSG_DATA(h);
 383                                 if (l < (int)sizeof(struct nlmsgerr)) {
 384                                         fprintf(stderr, "ERROR truncated\n");
 385                                 } else {
 386                                         errno = -merr->error;
 387                                         if (errno == 0) {
 388                                                 if (answer)
 389                                                         memcpy(answer, h,
 390                                                                h->nlmsg_len);
 391                                                 return 0;
 392                                         }
 393                                         perror("RTNETLINK answers");
 394                                 }
 395                                 return -1;
 396                         }
 397                         if (answer) {
 398                                 memcpy(answer, h, h->nlmsg_len);
 399                                 return 0;
 400                         }
 401
 402                         fprintf(stderr, "Unexpected reply!!!\n");
 403
 404                         status -= NLMSG_ALIGN(len);
 405                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 406                 }
 407                 if (msg.msg_flags & MSG_TRUNC) {
 408                         fprintf(stderr, "Message truncated\n");
 409                         continue;
 410                 }
 411                 if (status) {
 412                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 413                         exit(1);
 414                 }
 415         }
 416 }
 417
 418 int rtnl_listen(struct rtnl_handle *rtnl, rtnl_filter_t handler, void *jarg)
 419 {
 420         int status;
 421         struct nlmsghdr *h;
 422         struct sockaddr_nl nladdr;
 423         char buf[8192];
 424         struct iovec iov = {
 425                 .iov_base = buf,
 426                 .iov_len = sizeof(buf),
 427         };
 428         struct msghdr msg = {
 429                 .msg_name = &nladdr,
 430                 .msg_namelen = sizeof(nladdr),
 431                 .msg_iov = &iov,
 432                 .msg_iovlen = 1,
 433         };
 434
 435         memset(&nladdr, 0, sizeof(nladdr));
 436         nladdr.nl_family = AF_NETLINK;
 437         nladdr.nl_pid = 0;
 438         nladdr.nl_groups = 0;
 439
 440         while (1) {
 441                 iov.iov_len = sizeof(buf);
 442                 status = recvmsg(rtnl->fd, &msg, 0);
 443
 444                 if (status < 0) {
 445                         if (errno == EINTR || errno == EAGAIN)
 446                                 continue;
 447                         fprintf(stderr, "netlink receive error %s (%d)\n",
 448                                 strerror(errno), errno);
 449                         if (errno == ENOBUFS)
 450                                 continue;
 451                         return -1;
 452                 }
 453                 if (status == 0) {
 454                         fprintf(stderr, "EOF on netlink\n");
 455                         return -1;
 456                 }
 457                 if (msg.msg_namelen != sizeof(nladdr)) {
 458                         fprintf(stderr, "Sender address length == %d\n",
 459                                 msg.msg_namelen);
 460                         exit(1);
 461                 }
 462                 for (h = (struct nlmsghdr *)buf; status >= (int)sizeof(*h);) {
 463                         int err;
 464                         int len = h->nlmsg_len;
 465                         int l = len - sizeof(*h);
 466
 467                         if (l < 0 || len > status) {
 468                                 if (msg.msg_flags & MSG_TRUNC) {
 469                                         fprintf(stderr, "Truncated message\n");
 470                                         return -1;
 471                                 }
 472                                 fprintf(stderr,
 473                                         "!!!malformed message: len=%d\n", len);
 474                                 exit(1);
 475                         }
 476
 477                         err = handler(&nladdr, h, jarg);
 478                         if (err < 0)
 479                                 return err;
 480
 481                         status -= NLMSG_ALIGN(len);
 482                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 483                 }
 484                 if (msg.msg_flags & MSG_TRUNC) {
 485                         fprintf(stderr, "Message truncated\n");
 486                         continue;
 487                 }
 488                 if (status) {
 489                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 490                         exit(1);
 491                 }
 492         }
 493 }
 494
 495 int rtnl_from_file(FILE *rtnl, rtnl_filter_t handler, void *jarg)
 496 {
 497         struct sockaddr_nl nladdr;
 498         char buf[8192];
 499         struct nlmsghdr *h = (void *)buf;
 500
 501         memset(&nladdr, 0, sizeof(nladdr));
 502         nladdr.nl_family = AF_NETLINK;
 503         nladdr.nl_pid = 0;
 504         nladdr.nl_groups = 0;
 505
 506         while (1) {
 507                 int err;
 508                 size_t l, rl, arl;
 509
 510                 rl = sizeof(*h);
 511                 arl = fread(&buf, 1, rl, rtnl);
 512
 513                 if (arl != rl) {
 514                         if (arl == 0)
 515                                 return 0;
 516
 517                         if (ferror(rtnl))
 518                                 fprintf(stderr, "%s: header read failed\n",
 519                                         __func__);
 520                         else
 521                                 fprintf(stderr, "%s: truncated header\n",
 522                                         __func__);
 523                         return -1;
 524                 }
 525
 526                 l = h->nlmsg_len > rl ? h->nlmsg_len - rl : 0;
 527
 528                 if (l == 0 || (l + (size_t)NLMSG_HDRLEN) > sizeof(buf)) {
 529                         fprintf(stderr, "%s: malformed message: len=%zu @%lu\n",
 530                                 __func__, (size_t)h->nlmsg_len, ftell(rtnl));
 531                         return -1;
 532                 }
 533
 534                 rl = NLMSG_ALIGN(l);
 535                 arl = fread(NLMSG_DATA(h), 1, rl, rtnl);
 536
 537                 if (arl != rl) {
 538                         if (ferror(rtnl))
 539                                 fprintf(stderr, "%s: msg read failed\n",
 540                                         __func__);
 541                         else
 542                                 fprintf(stderr, "%s: truncated message\n",
 543                                         __func__);
 544                         return -1;
 545                 }
 546
 547                 err = handler(&nladdr, h, jarg);
 548                 if (err < 0)
 549                         return err;
 550         }
 551 }
 552
 553 int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
 554 {
 555         int len = RTA_LENGTH(4);
 556         struct rtattr *rta;
 557         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
 558                 fprintf(stderr,
 559                         "addattr32: Error! max allowed bound %d exceeded\n",
 560                         maxlen);
 561                 return -1;
 562         }
 563         rta = NLMSG_TAIL(n);
 564         rta->rta_type = type;
 565         rta->rta_len = len;
 566         memcpy(RTA_DATA(rta), &data, 4);
 567         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 568         return 0;
 569 }
 570
 571 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
 572               int alen)
 573 {
 574         int len = RTA_LENGTH(alen);
 575         struct rtattr *rta;
 576
 577         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len)) > maxlen) {
 578                 fprintf(stderr,
 579                         "addattr_l ERROR: message exceeded bound of %d\n",
 580                         maxlen);
 581                 return -1;
 582         }
 583         rta = NLMSG_TAIL(n);
 584         rta->rta_type = type;
 585         rta->rta_len = len;
 586
 587         if (data)
 588                 memcpy(RTA_DATA(rta), data, alen);
 589         else
 590                 assert(alen == 0);
 591
 592         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
 593         return 0;
 594 }
 595
 596 int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
 597 {
 598         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len)) > maxlen) {
 599                 fprintf(stderr,
 600                         "addraw_l ERROR: message exceeded bound of %d\n",
 601                         maxlen);
 602                 return -1;
 603         }
 604
 605         memcpy(NLMSG_TAIL(n), data, len);
 606         memset((uint8_t *)NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
 607         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
 608         return 0;
 609 }
 610
 611 struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
 612 {
 613         struct rtattr *nest = NLMSG_TAIL(n);
 614
 615         addattr_l(n, maxlen, type, NULL, 0);
 616         return nest;
 617 }
 618
 619 int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
 620 {
 621         nest->rta_len = (uint8_t *)NLMSG_TAIL(n) - (uint8_t *)nest;
 622         return n->nlmsg_len;
 623 }
 624
 625 struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
 626                                    const void *data, int len)
 627 {
 628         struct rtattr *start = NLMSG_TAIL(n);
 629
 630         addattr_l(n, maxlen, type, data, len);
 631         addattr_nest(n, maxlen, type);
 632         return start;
 633 }
 634
 635 int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
 636 {
 637         struct rtattr *nest = start + NLMSG_ALIGN(start->rta_len);
 638
 639         start->rta_len = (uint8_t *)NLMSG_TAIL(n) - (uint8_t *)start;
 640         addattr_nest_end(n, nest);
 641         return n->nlmsg_len;
 642 }
 643
 644 int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
 645 {
 646         int len = RTA_LENGTH(4);
 647         struct rtattr *subrta;
 648
 649         if ((int)(RTA_ALIGN(rta->rta_len) + len) > maxlen) {
 650                 fprintf(stderr,
 651                         "rta_addattr32: Error! max allowed bound %d exceeded\n",
 652                         maxlen);
 653                 return -1;
 654         }
 655         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
 656         subrta->rta_type = type;
 657         subrta->rta_len = len;
 658         memcpy(RTA_DATA(subrta), &data, 4);
 659         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 660         return 0;
 661 }
 662
 663 int rta_addattr_l(struct rtattr *rta, int maxlen, int type, const void *data,
 664                   int alen)
 665 {
 666         struct rtattr *subrta;
 667         int len = RTA_LENGTH(alen);
 668
 669         if ((int)(RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len)) > maxlen) {
 670                 fprintf(stderr,
 671                         "rta_addattr_l: Error! max allowed bound %d exceeded\n",
 672                         maxlen);
 673                 return -1;
 674         }
 675         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
 676         subrta->rta_type = type;
 677         subrta->rta_len = len;
 678         memcpy(RTA_DATA(subrta), data, alen);
 679         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
 680         return 0;
 681 }
 682
 683 int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 684 {
 685         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
 686         while (RTA_OK(rta, len)) {
 687                 if ((rta->rta_type <= max) && (!tb[rta->rta_type]))
 688                         tb[rta->rta_type] = rta;
 689                 rta = RTA_NEXT(rta, len);
 690         }
 691         if (len)
 692                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len,
 693                         rta->rta_len);
 694         return 0;
 695 }
 696
 697 int parse_rtattr_byindex(struct rtattr *tb[], int max, struct rtattr *rta,
 698                          int len)
 699 {
 700         int i = 0;
 701
 702         memset(tb, 0, sizeof(struct rtattr *) * max);
 703         while (RTA_OK(rta, len)) {
 704                 if (rta->rta_type <= max && i < max)
 705                         tb[i++] = rta;
 706                 rta = RTA_NEXT(rta, len);
 707         }
 708         if (len)
 709                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len,
 710                         rta->rta_len);
 711         return i;
 712 }
 713
 714 int __parse_rtattr_nested_compat(struct rtattr *tb[], int max,
 715                                  struct rtattr *rta, int len)
 716 {
 717         if ((int)RTA_PAYLOAD(rta) < len)
 718                 return -1;
 719         if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
 720                 rta = (struct rtattr *)(uint8_t *)RTA_DATA(rta)
 721                       + RTA_ALIGN(len);
 722                 return parse_rtattr_nested(tb, max, rta);
 723         }
 724         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
 725         return 0;
 726 }
 727
 728 #endif /* __linux__ */