net/l2tpv3.c

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2012-2014 Cisco Systems
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include <linux/ip.h>
  27 #include <netdb.h>
  28 #include "config-host.h"
  29 #include "net/net.h"
  30 #include "clients.h"
  31 #include "monitor/monitor.h"
  32 #include "qemu-common.h"
  33 #include "qemu/error-report.h"
  34 #include "qemu/option.h"
  35 #include "qemu/sockets.h"
  36 #include "qemu/iov.h"
  37 #include "qemu/main-loop.h"
  38
  39
  40 /* The buffer size needs to be investigated for optimum numbers and
  41  * optimum means of paging in on different systems. This size is
  42  * chosen to be sufficient to accommodate one packet with some headers
  43  */
  44
  45 #define BUFFER_ALIGN sysconf(_SC_PAGESIZE)
  46 #define BUFFER_SIZE 2048
  47 #define IOVSIZE 2
  48 #define MAX_L2TPV3_MSGCNT 64
  49 #define MAX_L2TPV3_IOVCNT (MAX_L2TPV3_MSGCNT * IOVSIZE)
  50
  51 /* Header set to 0x30000 signifies a data packet */
  52
  53 #define L2TPV3_DATA_PACKET 0x30000
  54
  55 /* IANA-assigned IP protocol ID for L2TPv3 */
  56
  57 #ifndef IPPROTO_L2TP
  58 #define IPPROTO_L2TP 0x73
  59 #endif
  60
  61 typedef struct NetL2TPV3State {
  62     NetClientState nc;
  63     int fd;
  64
  65     /*
  66      * these are used for xmit - that happens packet a time
  67      * and for first sign of life packet (easier to parse that once)
  68      */
  69
  70     uint8_t *header_buf;
  71     struct iovec *vec;
  72
  73     /*
  74      * these are used for receive - try to "eat" up to 32 packets at a time
  75      */
  76
  77     struct mmsghdr *msgvec;
  78
  79     /*
  80      * peer address
  81      */
  82
  83     struct sockaddr_storage *dgram_dst;
  84     uint32_t dst_size;
  85
  86     /*
  87      * L2TPv3 parameters
  88      */
  89
  90     uint64_t rx_cookie;
  91     uint64_t tx_cookie;
  92     uint32_t rx_session;
  93     uint32_t tx_session;
  94     uint32_t header_size;
  95     uint32_t counter;
  96
  97     /*
  98     * DOS avoidance in error handling
  99     */
 100
 101     bool header_mismatch;
 102
 103     /*
 104      * Ring buffer handling
 105      */
 106
 107     int queue_head;
 108     int queue_tail;
 109     int queue_depth;
 110
 111     /*
 112      * Precomputed offsets
 113      */
 114
 115     uint32_t offset;
 116     uint32_t cookie_offset;
 117     uint32_t counter_offset;
 118     uint32_t session_offset;
 119
 120     /* Poll Control */
 121
 122     bool read_poll;
 123     bool write_poll;
 124
 125     /* Flags */
 126
 127     bool ipv6;
 128     bool udp;
 129     bool has_counter;
 130     bool pin_counter;
 131     bool cookie;
 132     bool cookie_is_64;
 133
 134 } NetL2TPV3State;
 135
 136 static int l2tpv3_can_send(void *opaque);
 137 static void net_l2tpv3_send(void *opaque);
 138 static void l2tpv3_writable(void *opaque);
 139
 140 static void l2tpv3_update_fd_handler(NetL2TPV3State *s)
 141 {
 142     qemu_set_fd_handler2(s->fd,
 143                          s->read_poll ? l2tpv3_can_send : NULL,
 144                          s->read_poll ? net_l2tpv3_send     : NULL,
 145                          s->write_poll ? l2tpv3_writable : NULL,
 146                          s);
 147 }
 148
 149 static void l2tpv3_read_poll(NetL2TPV3State *s, bool enable)
 150 {
 151     if (s->read_poll != enable) {
 152         s->read_poll = enable;
 153         l2tpv3_update_fd_handler(s);
 154     }
 155 }
 156
 157 static void l2tpv3_write_poll(NetL2TPV3State *s, bool enable)
 158 {
 159     if (s->write_poll != enable) {
 160         s->write_poll = enable;
 161         l2tpv3_update_fd_handler(s);
 162     }
 163 }
 164
 165 static void l2tpv3_writable(void *opaque)
 166 {
 167     NetL2TPV3State *s = opaque;
 168     l2tpv3_write_poll(s, false);
 169     qemu_flush_queued_packets(&s->nc);
 170 }
 171
 172 static int l2tpv3_can_send(void *opaque)
 173 {
 174     NetL2TPV3State *s = opaque;
 175
 176     return qemu_can_send_packet(&s->nc);
 177 }
 178
 179 static void l2tpv3_send_completed(NetClientState *nc, ssize_t len)
 180 {
 181     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 182     l2tpv3_read_poll(s, true);
 183 }
 184
 185 static void l2tpv3_poll(NetClientState *nc, bool enable)
 186 {
 187     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 188     l2tpv3_write_poll(s, enable);
 189     l2tpv3_read_poll(s, enable);
 190 }
 191
 192 static void l2tpv3_form_header(NetL2TPV3State *s)
 193 {
 194     uint32_t *counter;
 195
 196     if (s->udp) {
 197         stl_be_p((uint32_t *) s->header_buf, L2TPV3_DATA_PACKET);
 198     }
 199     stl_be_p(
 200             (uint32_t *) (s->header_buf + s->session_offset),
 201             s->tx_session
 202         );
 203     if (s->cookie) {
 204         if (s->cookie_is_64) {
 205             stq_be_p(
 206                 (uint64_t *)(s->header_buf + s->cookie_offset),
 207                 s->tx_cookie
 208             );
 209         } else {
 210             stl_be_p(
 211                 (uint32_t *) (s->header_buf + s->cookie_offset),
 212                 s->tx_cookie
 213             );
 214         }
 215     }
 216     if (s->has_counter) {
 217         counter = (uint32_t *)(s->header_buf + s->counter_offset);
 218         if (s->pin_counter) {
 219             *counter = 0;
 220         } else {
 221             stl_be_p(counter, ++s->counter);
 222         }
 223     }
 224 }
 225
 226 static ssize_t net_l2tpv3_receive_dgram_iov(NetClientState *nc,
 227                     const struct iovec *iov,
 228                     int iovcnt)
 229 {
 230     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 231
 232     struct msghdr message;
 233     int ret;
 234
 235     if (iovcnt > MAX_L2TPV3_IOVCNT - 1) {
 236         error_report(
 237             "iovec too long %d > %d, change l2tpv3.h",
 238             iovcnt, MAX_L2TPV3_IOVCNT
 239         );
 240         return -1;
 241     }
 242     l2tpv3_form_header(s);
 243     memcpy(s->vec + 1, iov, iovcnt * sizeof(struct iovec));
 244     s->vec->iov_base = s->header_buf;
 245     s->vec->iov_len = s->offset;
 246     message.msg_name = s->dgram_dst;
 247     message.msg_namelen = s->dst_size;
 248     message.msg_iov = s->vec;
 249     message.msg_iovlen = iovcnt + 1;
 250     message.msg_control = NULL;
 251     message.msg_controllen = 0;
 252     message.msg_flags = 0;
 253     do {
 254         ret = sendmsg(s->fd, &message, 0);
 255     } while ((ret == -1) && (errno == EINTR));
 256     if (ret > 0) {
 257         ret -= s->offset;
 258     } else if (ret == 0) {
 259         /* belt and braces - should not occur on DGRAM
 260         * we should get an error and never a 0 send
 261         */
 262         ret = iov_size(iov, iovcnt);
 263     } else {
 264         /* signal upper layer that socket buffer is full */
 265         ret = -errno;
 266         if (ret == -EAGAIN || ret == -ENOBUFS) {
 267             l2tpv3_write_poll(s, true);
 268             ret = 0;
 269         }
 270     }
 271     return ret;
 272 }
 273
 274 static ssize_t net_l2tpv3_receive_dgram(NetClientState *nc,
 275                     const uint8_t *buf,
 276                     size_t size)
 277 {
 278     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 279
 280     struct iovec *vec;
 281     struct msghdr message;
 282     ssize_t ret = 0;
 283
 284     l2tpv3_form_header(s);
 285     vec = s->vec;
 286     vec->iov_base = s->header_buf;
 287     vec->iov_len = s->offset;
 288     vec++;
 289     vec->iov_base = (void *) buf;
 290     vec->iov_len = size;
 291     message.msg_name = s->dgram_dst;
 292     message.msg_namelen = s->dst_size;
 293     message.msg_iov = s->vec;
 294     message.msg_iovlen = 2;
 295     message.msg_control = NULL;
 296     message.msg_controllen = 0;
 297     message.msg_flags = 0;
 298     do {
 299         ret = sendmsg(s->fd, &message, 0);
 300     } while ((ret == -1) && (errno == EINTR));
 301     if (ret > 0) {
 302         ret -= s->offset;
 303     } else if (ret == 0) {
 304         /* belt and braces - should not occur on DGRAM
 305         * we should get an error and never a 0 send
 306         */
 307         ret = size;
 308     } else {
 309         ret = -errno;
 310         if (ret == -EAGAIN || ret == -ENOBUFS) {
 311             /* signal upper layer that socket buffer is full */
 312             l2tpv3_write_poll(s, true);
 313             ret = 0;
 314         }
 315     }
 316     return ret;
 317 }
 318
 319 static int l2tpv3_verify_header(NetL2TPV3State *s, uint8_t *buf)
 320 {
 321
 322     uint32_t *session;
 323     uint64_t cookie;
 324
 325     if ((!s->udp) && (!s->ipv6)) {
 326         buf += sizeof(struct iphdr) /* fix for ipv4 raw */;
 327     }
 328
 329     /* we do not do a strict check for "data" packets as per
 330     * the RFC spec because the pure IP spec does not have
 331     * that anyway.
 332     */
 333
 334     if (s->cookie) {
 335         if (s->cookie_is_64) {
 336             cookie = ldq_be_p(buf + s->cookie_offset);
 337         } else {
 338             cookie = ldl_be_p(buf + s->cookie_offset);
 339         }
 340         if (cookie != s->rx_cookie) {
 341             if (!s->header_mismatch) {
 342                 error_report("unknown cookie id");
 343             }
 344             return -1;
 345         }
 346     }
 347     session = (uint32_t *) (buf + s->session_offset);
 348     if (ldl_be_p(session) != s->rx_session) {
 349         if (!s->header_mismatch) {
 350             error_report("session mismatch");
 351         }
 352         return -1;
 353     }
 354     return 0;
 355 }
 356
 357 static void net_l2tpv3_process_queue(NetL2TPV3State *s)
 358 {
 359     int size = 0;
 360     struct iovec *vec;
 361     bool bad_read;
 362     int data_size;
 363     struct mmsghdr *msgvec;
 364
 365     /* go into ring mode only if there is a "pending" tail */
 366     if (s->queue_depth > 0) {
 367         do {
 368             msgvec = s->msgvec + s->queue_tail;
 369             if (msgvec->msg_len > 0) {
 370                 data_size = msgvec->msg_len - s->header_size;
 371                 vec = msgvec->msg_hdr.msg_iov;
 372                 if ((data_size > 0) &&
 373                     (l2tpv3_verify_header(s, vec->iov_base) == 0)) {
 374                     vec++;
 375                     /* Use the legacy delivery for now, we will
 376                      * switch to using our own ring as a queueing mechanism
 377                      * at a later date
 378                      */
 379                     size = qemu_send_packet_async(
 380                             &s->nc,
 381                             vec->iov_base,
 382                             data_size,
 383                             l2tpv3_send_completed
 384                         );
 385                     if (size == 0) {
 386                         l2tpv3_read_poll(s, false);
 387                     }
 388                     bad_read = false;
 389                 } else {
 390                     bad_read = true;
 391                     if (!s->header_mismatch) {
 392                         /* report error only once */
 393                         error_report("l2tpv3 header verification failed");
 394                         s->header_mismatch = true;
 395                     }
 396                 }
 397             } else {
 398                 bad_read = true;
 399             }
 400             s->queue_tail = (s->queue_tail + 1) % MAX_L2TPV3_MSGCNT;
 401             s->queue_depth--;
 402         } while (
 403                 (s->queue_depth > 0) &&
 404                  qemu_can_send_packet(&s->nc) &&
 405                 ((size > 0) || bad_read)
 406             );
 407     }
 408 }
 409
 410 static void net_l2tpv3_send(void *opaque)
 411 {
 412     NetL2TPV3State *s = opaque;
 413     int target_count, count;
 414     struct mmsghdr *msgvec;
 415
 416     /* go into ring mode only if there is a "pending" tail */
 417
 418     if (s->queue_depth) {
 419
 420         /* The ring buffer we use has variable intake
 421          * count of how much we can read varies - adjust accordingly
 422          */
 423
 424         target_count = MAX_L2TPV3_MSGCNT - s->queue_depth;
 425
 426         /* Ensure we do not overrun the ring when we have
 427          * a lot of enqueued packets
 428          */
 429
 430         if (s->queue_head + target_count > MAX_L2TPV3_MSGCNT) {
 431             target_count = MAX_L2TPV3_MSGCNT - s->queue_head;
 432         }
 433     } else {
 434
 435         /* we do not have any pending packets - we can use
 436         * the whole message vector linearly instead of using
 437         * it as a ring
 438         */
 439
 440         s->queue_head = 0;
 441         s->queue_tail = 0;
 442         target_count = MAX_L2TPV3_MSGCNT;
 443     }
 444
 445     msgvec = s->msgvec + s->queue_head;
 446     if (target_count > 0) {
 447         do {
 448             count = recvmmsg(
 449                 s->fd,
 450                 msgvec,
 451                 target_count, MSG_DONTWAIT, NULL);
 452         } while ((count == -1) && (errno == EINTR));
 453         if (count < 0) {
 454             /* Recv error - we still need to flush packets here,
 455              * (re)set queue head to current position
 456              */
 457             count = 0;
 458         }
 459         s->queue_head = (s->queue_head + count) % MAX_L2TPV3_MSGCNT;
 460         s->queue_depth += count;
 461     }
 462     net_l2tpv3_process_queue(s);
 463 }
 464
 465 static void destroy_vector(struct mmsghdr *msgvec, int count, int iovcount)
 466 {
 467     int i, j;
 468     struct iovec *iov;
 469     struct mmsghdr *cleanup = msgvec;
 470     if (cleanup) {
 471         for (i = 0; i < count; i++) {
 472             if (cleanup->msg_hdr.msg_iov) {
 473                 iov = cleanup->msg_hdr.msg_iov;
 474                 for (j = 0; j < iovcount; j++) {
 475                     g_free(iov->iov_base);
 476                     iov++;
 477                 }
 478                 g_free(cleanup->msg_hdr.msg_iov);
 479             }
 480             cleanup++;
 481         }
 482         g_free(msgvec);
 483     }
 484 }
 485
 486 static struct mmsghdr *build_l2tpv3_vector(NetL2TPV3State *s, int count)
 487 {
 488     int i;
 489     struct iovec *iov;
 490     struct mmsghdr *msgvec, *result;
 491
 492     msgvec = g_malloc(sizeof(struct mmsghdr) * count);
 493     result = msgvec;
 494     for (i = 0; i < count ; i++) {
 495         msgvec->msg_hdr.msg_name = NULL;
 496         msgvec->msg_hdr.msg_namelen = 0;
 497         iov =  g_malloc(sizeof(struct iovec) * IOVSIZE);
 498         msgvec->msg_hdr.msg_iov = iov;
 499         iov->iov_base = g_malloc(s->header_size);
 500         iov->iov_len = s->header_size;
 501         iov++ ;
 502         iov->iov_base = qemu_memalign(BUFFER_ALIGN, BUFFER_SIZE);
 503         iov->iov_len = BUFFER_SIZE;
 504         msgvec->msg_hdr.msg_iovlen = 2;
 505         msgvec->msg_hdr.msg_control = NULL;
 506         msgvec->msg_hdr.msg_controllen = 0;
 507         msgvec->msg_hdr.msg_flags = 0;
 508         msgvec++;
 509     }
 510     return result;
 511 }
 512
 513 static void net_l2tpv3_cleanup(NetClientState *nc)
 514 {
 515     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 516     qemu_purge_queued_packets(nc);
 517     l2tpv3_read_poll(s, false);
 518     l2tpv3_write_poll(s, false);
 519     if (s->fd >= 0) {
 520         close(s->fd);
 521     }
 522     destroy_vector(s->msgvec, MAX_L2TPV3_MSGCNT, IOVSIZE);
 523     g_free(s->vec);
 524     g_free(s->header_buf);
 525     g_free(s->dgram_dst);
 526 }
 527
 528 static NetClientInfo net_l2tpv3_info = {
 529     .type = NET_CLIENT_OPTIONS_KIND_L2TPV3,
 530     .size = sizeof(NetL2TPV3State),
 531     .receive = net_l2tpv3_receive_dgram,
 532     .receive_iov = net_l2tpv3_receive_dgram_iov,
 533     .poll = l2tpv3_poll,
 534     .cleanup = net_l2tpv3_cleanup,
 535 };
 536
 537 int net_init_l2tpv3(const NetClientOptions *opts,
 538                     const char *name,
 539                     NetClientState *peer)
 540 {
 541
 542
 543     const NetdevL2TPv3Options *l2tpv3;
 544     NetL2TPV3State *s;
 545     NetClientState *nc;
 546     int fd = -1, gairet;
 547     struct addrinfo hints;
 548     struct addrinfo *result = NULL;
 549     char *srcport, *dstport;
 550
 551     nc = qemu_new_net_client(&net_l2tpv3_info, peer, "l2tpv3", name);
 552
 553     s = DO_UPCAST(NetL2TPV3State, nc, nc);
 554
 555     s->queue_head = 0;
 556     s->queue_tail = 0;
 557     s->header_mismatch = false;
 558
 559     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_L2TPV3);
 560     l2tpv3 = opts->l2tpv3;
 561
 562     if (l2tpv3->has_ipv6 && l2tpv3->ipv6) {
 563         s->ipv6 = l2tpv3->ipv6;
 564     } else {
 565         s->ipv6 = false;
 566     }
 567
 568     if ((l2tpv3->has_offset) && (l2tpv3->offset > 256)) {
 569         error_report("l2tpv3_open : offset must be less than 256 bytes");
 570         goto outerr;
 571     }
 572
 573     if (l2tpv3->has_rxcookie || l2tpv3->has_txcookie) {
 574         if (l2tpv3->has_rxcookie && l2tpv3->has_txcookie) {
 575             s->cookie = true;
 576         } else {
 577             goto outerr;
 578         }
 579     } else {
 580         s->cookie = false;
 581     }
 582
 583     if (l2tpv3->has_cookie64 || l2tpv3->cookie64) {
 584         s->cookie_is_64  = true;
 585     } else {
 586         s->cookie_is_64  = false;
 587     }
 588
 589     if (l2tpv3->has_udp && l2tpv3->udp) {
 590         s->udp = true;
 591         if (!(l2tpv3->has_srcport && l2tpv3->has_dstport)) {
 592             error_report("l2tpv3_open : need both src and dst port for udp");
 593             goto outerr;
 594         } else {
 595             srcport = l2tpv3->srcport;
 596             dstport = l2tpv3->dstport;
 597         }
 598     } else {
 599         s->udp = false;
 600         srcport = NULL;
 601         dstport = NULL;
 602     }
 603
 604
 605     s->offset = 4;
 606     s->session_offset = 0;
 607     s->cookie_offset = 4;
 608     s->counter_offset = 4;
 609
 610     s->tx_session = l2tpv3->txsession;
 611     if (l2tpv3->has_rxsession) {
 612         s->rx_session = l2tpv3->rxsession;
 613     } else {
 614         s->rx_session = s->tx_session;
 615     }
 616
 617     if (s->cookie) {
 618         s->rx_cookie = l2tpv3->rxcookie;
 619         s->tx_cookie = l2tpv3->txcookie;
 620         if (s->cookie_is_64 == true) {
 621             /* 64 bit cookie */
 622             s->offset += 8;
 623             s->counter_offset += 8;
 624         } else {
 625             /* 32 bit cookie */
 626             s->offset += 4;
 627             s->counter_offset += 4;
 628         }
 629     }
 630
 631     memset(&hints, 0, sizeof(hints));
 632
 633     if (s->ipv6) {
 634         hints.ai_family = AF_INET6;
 635     } else {
 636         hints.ai_family = AF_INET;
 637     }
 638     if (s->udp) {
 639         hints.ai_socktype = SOCK_DGRAM;
 640         hints.ai_protocol = 0;
 641         s->offset += 4;
 642         s->counter_offset += 4;
 643         s->session_offset += 4;
 644         s->cookie_offset += 4;
 645     } else {
 646         hints.ai_socktype = SOCK_RAW;
 647         hints.ai_protocol = IPPROTO_L2TP;
 648     }
 649
 650     gairet = getaddrinfo(l2tpv3->src, srcport, &hints, &result);
 651
 652     if ((gairet != 0) || (result == NULL)) {
 653         error_report(
 654             "l2tpv3_open : could not resolve src, errno = %s",
 655             gai_strerror(gairet)
 656         );
 657         goto outerr;
 658     }
 659     fd = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
 660     if (fd == -1) {
 661         fd = -errno;
 662         error_report("l2tpv3_open : socket creation failed, errno = %d", -fd);
 663         goto outerr;
 664     }
 665     if (bind(fd, (struct sockaddr *) result->ai_addr, result->ai_addrlen)) {
 666         error_report("l2tpv3_open :  could not bind socket err=%i", errno);
 667         goto outerr;
 668     }
 669     if (result) {
 670         freeaddrinfo(result);
 671     }
 672
 673     memset(&hints, 0, sizeof(hints));
 674
 675     if (s->ipv6) {
 676         hints.ai_family = AF_INET6;
 677     } else {
 678         hints.ai_family = AF_INET;
 679     }
 680     if (s->udp) {
 681         hints.ai_socktype = SOCK_DGRAM;
 682         hints.ai_protocol = 0;
 683     } else {
 684         hints.ai_socktype = SOCK_RAW;
 685         hints.ai_protocol = IPPROTO_L2TP;
 686     }
 687
 688     result = NULL;
 689     gairet = getaddrinfo(l2tpv3->dst, dstport, &hints, &result);
 690     if ((gairet != 0) || (result == NULL)) {
 691         error_report(
 692             "l2tpv3_open : could not resolve dst, error = %s",
 693             gai_strerror(gairet)
 694         );
 695         goto outerr;
 696     }
 697
 698     s->dgram_dst = g_malloc(sizeof(struct sockaddr_storage));
 699     memset(s->dgram_dst, '\0' , sizeof(struct sockaddr_storage));
 700     memcpy(s->dgram_dst, result->ai_addr, result->ai_addrlen);
 701     s->dst_size = result->ai_addrlen;
 702
 703     if (result) {
 704         freeaddrinfo(result);
 705     }
 706
 707     if (l2tpv3->has_counter && l2tpv3->counter) {
 708         s->has_counter = true;
 709         s->offset += 4;
 710     } else {
 711         s->has_counter = false;
 712     }
 713
 714     if (l2tpv3->has_pincounter && l2tpv3->pincounter) {
 715         s->has_counter = true;  /* pin counter implies that there is counter */
 716         s->pin_counter = true;
 717     } else {
 718         s->pin_counter = false;
 719     }
 720
 721     if (l2tpv3->has_offset) {
 722         /* extra offset */
 723         s->offset += l2tpv3->offset;
 724     }
 725
 726     if ((s->ipv6) || (s->udp)) {
 727         s->header_size = s->offset;
 728     } else {
 729         s->header_size = s->offset + sizeof(struct iphdr);
 730     }
 731
 732     s->msgvec = build_l2tpv3_vector(s, MAX_L2TPV3_MSGCNT);
 733     s->vec = g_malloc(sizeof(struct iovec) * MAX_L2TPV3_IOVCNT);
 734     s->header_buf = g_malloc(s->header_size);
 735
 736     qemu_set_nonblock(fd);
 737
 738     s->fd = fd;
 739     s->counter = 0;
 740
 741     l2tpv3_read_poll(s, true);
 742
 743     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 744              "l2tpv3: connected");
 745     return 0;
 746 outerr:
 747     qemu_del_net_client(nc);
 748     if (fd >= 0) {
 749         close(fd);
 750     }
 751     if (result) {
 752         freeaddrinfo(result);
 753     }
 754     return -1;
 755 }
 756