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