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