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