src/vpn/gnunet-daemon-vpn.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2010 Christian Grothoff
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file vpn/gnunet-daemon-vpn.c
  23  * @brief
  24  * @author Philipp Toelke
  25  */
  26 #include "platform.h"
  27 #include "gnunet_getopt_lib.h"
  28 #include "gnunet_program_lib.h"
  29 #include "gnunet-vpn-packet.h"
  30 #include "gnunet_common.h"
  31 #include "gnunet_protocols.h"
  32 #include "gnunet_applications.h"
  33 #include <gnunet_mesh_service.h>
  34 #include "gnunet_client_lib.h"
  35 #include "gnunet_container_lib.h"
  36 #include "gnunet_constants.h"
  37 #include <block_dns.h>
  38 #include "gnunet-daemon-vpn-helper.h"
  39 #include "gnunet-daemon-vpn-dns.h"
  40 #include "gnunet-daemon-vpn.h"
  41 #include "gnunet-vpn-checksum.h"
  42
  43 const struct GNUNET_CONFIGURATION_Handle *cfg;
  44 struct GNUNET_MESH_Handle *mesh_handle;
  45 struct GNUNET_CONTAINER_MultiHashMap* hashmap;
  46 static struct GNUNET_CONTAINER_Heap *heap;
  47
  48 struct tunnel_notify_queue
  49 {
  50   struct tunnel_notify_queue* next;
  51   struct tunnel_notify_queue* prev;
  52   size_t len;
  53   void* cls;
  54 };
  55
  56 /**
  57  * If there are at least this many address-mappings, old ones will be removed
  58  */
  59 static long long unsigned int max_mappings = 200;
  60
  61 /**
  62  * Final status code.
  63  */
  64 static int ret;
  65
  66 /**
  67  * This hashmap contains the mapping from peer, service-descriptor,
  68  * source-port and destination-port to a socket
  69  */
  70 static struct GNUNET_CONTAINER_MultiHashMap *udp_connections;
  71
  72 GNUNET_SCHEDULER_TaskIdentifier conn_task;
  73
  74 GNUNET_SCHEDULER_TaskIdentifier shs_task;
  75
  76 /**
  77  * Function scheduled as very last function, cleans up after us
  78  *{{{
  79  */
  80 static void
  81 cleanup(void* cls __attribute__((unused)), const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
  82     GNUNET_assert (0 != (tskctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN));
  83
  84     /* stop the helper */
  85     cleanup_helper(helper_handle);
  86
  87     /* close the connection to the service-dns */
  88     if (dns_connection != NULL)
  89       {
  90         GNUNET_CLIENT_disconnect (dns_connection, GNUNET_NO);
  91         dns_connection = NULL;
  92       }
  93
  94     if (mesh_handle != NULL)
  95       {
  96         GNUNET_MESH_disconnect(mesh_handle);
  97         mesh_handle = NULL;
  98       }
  99     if (GNUNET_SCHEDULER_NO_TASK != shs_task)
 100       {
 101         GNUNET_SCHEDULER_cancel (shs_task);
 102         shs_task = GNUNET_SCHEDULER_NO_TASK;
 103       }
 104     if (GNUNET_SCHEDULER_NO_TASK != conn_task)
 105       {
 106         GNUNET_SCHEDULER_cancel (conn_task);
 107         conn_task = GNUNET_SCHEDULER_NO_TASK;
 108       }
 109 }
 110 /*}}}*/
 111
 112 /**
 113  * @return the hash of the IP-Address if a mapping exists, NULL otherwise
 114  */
 115 GNUNET_HashCode*
 116 address6_mapping_exists(unsigned char addr[]) {
 117     GNUNET_HashCode* key = GNUNET_malloc(sizeof(GNUNET_HashCode));
 118     unsigned char* k = (unsigned char*)key;
 119     memset(key, 0, sizeof(GNUNET_HashCode));
 120     unsigned int i;
 121     for (i = 0; i < 16; i++)
 122         k[15-i] = addr[i];
 123
 124     if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains(hashmap, key))
 125       return key;
 126     else
 127       {
 128         GNUNET_free(key);
 129         return NULL;
 130       }
 131 }
 132
 133 /**
 134  * @return the hash of the IP-Address if a mapping exists, NULL otherwise
 135  */
 136 GNUNET_HashCode *
 137 address4_mapping_exists (uint32_t addr)
 138 {
 139   GNUNET_HashCode *key = GNUNET_malloc (sizeof (GNUNET_HashCode));
 140   memset (key, 0, sizeof (GNUNET_HashCode));
 141   unsigned char *c = (unsigned char *) &addr;
 142   unsigned char *k = (unsigned char *) key;
 143   unsigned int i;
 144   for (i = 0; i < 4; i++)
 145     k[3 - i] = c[i];
 146
 147   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 148               "a4_m_e: getting with key %08x, addr is %08x, %d.%d.%d.%d\n",
 149               *((uint32_t *) (key)), addr, c[0], c[1], c[2], c[3]);
 150
 151   if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains (hashmap, key))
 152     return key;
 153   else
 154     {
 155       GNUNET_free (key);
 156       GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Mapping not found!\n");
 157       return NULL;
 158     }
 159 }
 160
 161 static void
 162 collect_mappings(void* cls __attribute__((unused)), const struct GNUNET_SCHEDULER_TaskContext* tc) {
 163     if ( (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0)
 164       return;
 165
 166     struct map_entry* me = GNUNET_CONTAINER_heap_remove_root(heap);
 167
 168     /* This is free()ed memory! */
 169     me->heap_node = NULL;
 170
 171     /* FIXME! GNUNET_MESH_close_tunnel(me->tunnel); */
 172
 173     GNUNET_CONTAINER_multihashmap_remove(hashmap, &me->hash, me);
 174
 175     GNUNET_free(me);
 176 }
 177
 178 void
 179 send_icmp4_response(void* cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 180     if ( (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0)
 181       return;
 182
 183     struct ip_icmp* request = cls;
 184
 185     struct ip_icmp* response = alloca(ntohs(request->shdr.size));
 186     GNUNET_assert(response != NULL);
 187     memset(response, 0, ntohs(request->shdr.size));
 188
 189     response->shdr.size = request->shdr.size;
 190     response->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 191
 192     response->tun.flags = 0;
 193     response->tun.type = htons(0x0800);
 194
 195     response->ip_hdr.hdr_lngth = 5;
 196     response->ip_hdr.version = 4;
 197     response->ip_hdr.proto = 0x01;
 198     response->ip_hdr.dadr = request->ip_hdr.sadr;
 199     response->ip_hdr.sadr = request->ip_hdr.dadr;
 200     response->ip_hdr.tot_lngth = request->ip_hdr.tot_lngth;
 201
 202     response->ip_hdr.chks = calculate_ip_checksum((uint16_t*)&response->ip_hdr, 20);
 203
 204     response->icmp_hdr.code = 0;
 205     response->icmp_hdr.type = 0x0;
 206
 207     /* Magic, more Magic! */
 208     response->icmp_hdr.chks = request->icmp_hdr.chks + 0x8;
 209
 210     /* Copy the rest of the packet */
 211     memcpy(response+1, request+1, ntohs(request->shdr.size) - sizeof(struct ip_icmp));
 212
 213     write_to_helper(response, ntohs(response->shdr.size));
 214
 215     GNUNET_free(request);
 216 }
 217
 218 void
 219 send_icmp6_response(void* cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 220     if ( (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0)
 221       return;
 222
 223     struct ip6_icmp* request = cls;
 224
 225     struct ip6_icmp* response = alloca(ntohs(request->shdr.size));
 226     GNUNET_assert(response != NULL);
 227     memset(response, 0, ntohs(request->shdr.size));
 228
 229     response->shdr.size = request->shdr.size;
 230     response->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 231
 232     response->tun.flags = 0;
 233     response->tun.type = htons(0x86dd);
 234
 235     response->ip6_hdr.hoplmt = 255;
 236     response->ip6_hdr.paylgth = request->ip6_hdr.paylgth;
 237     response->ip6_hdr.nxthdr = 0x3a;
 238     response->ip6_hdr.version = 6;
 239     memcpy(&response->ip6_hdr.sadr, &request->ip6_hdr.dadr, 16);
 240     memcpy(&response->ip6_hdr.dadr, &request->ip6_hdr.sadr, 16);
 241
 242     response->icmp_hdr.code = 0;
 243     response->icmp_hdr.type = 0x81;
 244
 245     /* Magic, more Magic! */
 246     response->icmp_hdr.chks = request->icmp_hdr.chks - 0x1;
 247
 248     /* Copy the rest of the packet */
 249     memcpy(response+1, request+1, ntohs(request->shdr.size) - sizeof(struct ip6_icmp));
 250
 251     write_to_helper(response, ntohs(response->shdr.size));
 252
 253     GNUNET_free(request);
 254 }
 255
 256 /**
 257  * cls is the pointer to a GNUNET_MessageHeader that is
 258  * followed by the service-descriptor and the packet that should be sent;
 259  */
 260 static size_t
 261 send_pkt_to_peer_notify_callback (void *cls, size_t size, void *buf)
 262 {
 263   struct GNUNET_MESH_Tunnel **tunnel = cls;
 264   GNUNET_MESH_tunnel_set_data(*tunnel, NULL);
 265   struct GNUNET_MessageHeader *hdr =
 266     (struct GNUNET_MessageHeader *) (tunnel + 1);
 267   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "send_pkt_to_peer_notify_callback: buf = %x; size = %u;\n", buf, size);
 268   GNUNET_assert (size >= ntohs (hdr->size));
 269   memcpy (buf, hdr, ntohs (hdr->size));
 270   size = ntohs(hdr->size);
 271   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sent!\n");
 272
 273   if (NULL != GNUNET_MESH_tunnel_get_head(*tunnel))
 274     {
 275       struct tunnel_notify_queue* element = GNUNET_MESH_tunnel_get_head(*tunnel);
 276       struct tunnel_notify_queue* head = GNUNET_MESH_tunnel_get_head(*tunnel);
 277       struct tunnel_notify_queue* tail = GNUNET_MESH_tunnel_get_tail(*tunnel);
 278
 279       GNUNET_CONTAINER_DLL_remove(head, tail, element);
 280
 281       GNUNET_MESH_tunnel_set_head(*tunnel, head);
 282       GNUNET_MESH_tunnel_set_tail(*tunnel, tail);
 283
 284       struct GNUNET_MESH_TransmitHandle* th = GNUNET_MESH_notify_transmit_ready (*tunnel,
 285                                                                                  GNUNET_NO,
 286                                                                                  42,
 287                                                                                  GNUNET_TIME_relative_divide
 288                                                                                  (GNUNET_CONSTANTS_MAX_CORK_DELAY, 2),
 289                                                                                  (const struct GNUNET_PeerIdentity *)
 290                                                                                  NULL, element->len,
 291                                                                                  send_pkt_to_peer_notify_callback, element->cls);
 292       /* save the handle */
 293       GNUNET_MESH_tunnel_set_data(*tunnel, th);
 294     }
 295   GNUNET_free (cls);
 296
 297   return size;
 298 }
 299
 300 unsigned int
 301 port_in_ports (uint64_t ports, uint16_t port)
 302 {
 303   uint16_t *ps = (uint16_t *) & ports;
 304   return ps[0] == port || ps[1] == port || ps[2] == port || ps[3] == port;
 305 }
 306
 307 void
 308 send_pkt_to_peer (void *cls,
 309                   const struct GNUNET_PeerIdentity *peer,
 310                   const struct GNUNET_TRANSPORT_ATS_Information *atsi __attribute__((unused)))
 311 {
 312   /* peer == NULL means that all peers in this request are connected */
 313   if (peer == NULL) return;
 314   struct GNUNET_MESH_Tunnel **tunnel = cls;
 315   struct GNUNET_MessageHeader *hdr =
 316     (struct GNUNET_MessageHeader *) (tunnel + 1);
 317
 318   GNUNET_assert(NULL != tunnel);
 319   GNUNET_assert(NULL != *tunnel);
 320
 321   if (NULL == GNUNET_MESH_tunnel_get_data(*tunnel))
 322     {
 323       struct GNUNET_MESH_TransmitHandle* th = GNUNET_MESH_notify_transmit_ready (*tunnel,
 324                                                                                  GNUNET_NO,
 325                                                                                  42,
 326                                                                                  GNUNET_TIME_relative_divide(GNUNET_CONSTANTS_MAX_CORK_DELAY, 2),
 327                                                                                  (const struct GNUNET_PeerIdentity *)NULL,
 328                                                                                  ntohs(hdr->size),
 329                                                                                  send_pkt_to_peer_notify_callback,
 330                                                                                  cls);
 331       GNUNET_MESH_tunnel_set_data(*tunnel, th);
 332     }
 333   else
 334     {
 335      struct tunnel_notify_queue* head = GNUNET_MESH_tunnel_get_head(*tunnel);
 336      struct tunnel_notify_queue* tail = GNUNET_MESH_tunnel_get_tail(*tunnel);
 337      struct tunnel_notify_queue* element = GNUNET_malloc(sizeof *element);
 338
 339      element->cls = cls;
 340      element->len = ntohs(hdr->size);
 341
 342      GNUNET_CONTAINER_DLL_insert_tail(head, tail, element);
 343
 344      GNUNET_MESH_tunnel_set_head(*tunnel, head);
 345      GNUNET_MESH_tunnel_set_tail(*tunnel, tail);
 346     }
 347 }
 348
 349 /**
 350  * Create a new Address from an answer-packet
 351  */
 352 void
 353 new_ip6addr(unsigned char* buf, const GNUNET_HashCode *peer, const GNUNET_HashCode *service_desc) { /* {{{ */
 354     char* ipv6addr;
 355     unsigned long long ipv6prefix;
 356     GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr));
 357     GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_number(cfg, "vpn", "IPV6PREFIX", &ipv6prefix));
 358     GNUNET_assert(ipv6prefix < 127);
 359     ipv6prefix = (ipv6prefix + 7)/8;
 360
 361     inet_pton (AF_INET6, ipv6addr, buf);
 362     GNUNET_free(ipv6addr);
 363
 364     int peer_length = 16 - ipv6prefix - 6;
 365     if (peer_length <= 0)
 366       peer_length = 0;
 367
 368     int service_length = 16 - ipv6prefix - peer_length;
 369     if (service_length <= 0)
 370       service_length = 0;
 371
 372     memcpy(buf+ipv6prefix, service_desc, service_length);
 373     memcpy(buf+ipv6prefix+service_length, peer, peer_length);
 374 }
 375 /*}}}*/
 376
 377
 378 /**
 379  * Create a new Address from an answer-packet
 380  */
 381 void
 382 new_ip6addr_remote (unsigned char *buf, unsigned char *addr, char addrlen)
 383 {                               /* {{{ */
 384   char *ipv6addr;
 385   unsigned long long ipv6prefix;
 386   GNUNET_assert (GNUNET_OK ==
 387                  GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
 388                                                         "IPV6ADDR",
 389                                                         &ipv6addr));
 390   GNUNET_assert (GNUNET_OK ==
 391                  GNUNET_CONFIGURATION_get_value_number (cfg, "vpn",
 392                                                         "IPV6PREFIX",
 393                                                         &ipv6prefix));
 394   GNUNET_assert (ipv6prefix < 127);
 395   ipv6prefix = (ipv6prefix + 7) / 8;
 396
 397   inet_pton (AF_INET6, ipv6addr, buf);
 398   GNUNET_free (ipv6addr);
 399
 400   int local_length = 16 - ipv6prefix;
 401
 402   memcpy (buf + ipv6prefix, addr, GNUNET_MIN (addrlen, local_length));
 403 }
 404 /*}}}*/
 405
 406 /**
 407  * Create a new Address from an answer-packet
 408  */
 409 void
 410 new_ip4addr_remote (unsigned char *buf, unsigned char *addr, char addrlen)
 411 {                               /* {{{ */
 412   char *ipv4addr;
 413   char *ipv4mask;
 414   GNUNET_assert (GNUNET_OK ==
 415                  GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
 416                                                         "IPV4ADDR",
 417                                                         &ipv4addr));
 418   GNUNET_assert (GNUNET_OK ==
 419                  GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
 420                                                         "IPV4MASK",
 421                                                         &ipv4mask));
 422   uint32_t mask;
 423   inet_pton (AF_INET, ipv4addr, buf);
 424   int r = inet_pton (AF_INET, ipv4mask, &mask);
 425   mask = htonl(mask);
 426   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "inet_pton: %d; %m; mask: %08x\n", r, mask);
 427
 428   GNUNET_free (ipv4addr);
 429
 430   int c;
 431
 432   if (mask)
 433     {
 434       mask = (mask ^ (mask - 1)) >> 1;
 435       for (c = 0; mask; c++)
 436         {
 437           mask >>= 1;
 438         }
 439     }
 440   else
 441     {
 442       c = CHAR_BIT * sizeof(mask);
 443     }
 444
 445   c = 32-c;
 446   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "The mask %s has %d leading 1s.\n", ipv4mask, c);
 447
 448   GNUNET_free (ipv4mask);
 449
 450   if (c % 8 == 0)
 451     c = c / 8;
 452   else
 453     GNUNET_assert(0);
 454
 455   memcpy (buf + c, addr, GNUNET_MIN (addrlen, c));
 456 }
 457 /*}}}*/
 458
 459 /**
 460  * This gets scheduled with cls pointing to an answer_packet and does everything
 461  * needed in order to send it to the helper.
 462  *
 463  * At the moment this means "inventing" and IPv6-Address for .gnunet-services and
 464  * doing nothing for "real" services.
 465  */
 466 void
 467 process_answer(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
 468     if ( (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0)
 469       return;
 470
 471     struct answer_packet* pkt = cls;
 472     struct answer_packet_list* list;
 473
 474     /* This answer is about a .gnunet-service
 475      *
 476      * It contains an almost complete DNS-Response, we have to fill in the ip
 477      * at the offset pkt->addroffset
 478      */
 479     if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_SERVICE)
 480       {
 481         pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 482
 483         GNUNET_HashCode key;
 484         memset(&key, 0, sizeof(GNUNET_HashCode));
 485
 486         unsigned char* c = ((unsigned char*)pkt)+ntohs(pkt->addroffset);
 487         unsigned char* k = (unsigned char*)&key;
 488         new_ip6addr(c, &pkt->service_descr.peer, &pkt->service_descr.service_descriptor);
 489         /*
 490          * Copy the newly generated ip-address to the key backwarts (as only the first part is hashed)
 491          */
 492         unsigned int i;
 493         for (i = 0; i < 16; i++)
 494             k[15-i] = c[i];
 495
 496         uint16_t namelen = strlen((char*)pkt->data+12)+1;
 497
 498         struct map_entry* value = GNUNET_malloc(sizeof(struct map_entry) + namelen);
 499         char* name = (char*)(value +1);
 500
 501         value->namelen = namelen;
 502         memcpy(name, pkt->data+12, namelen);
 503
 504         memcpy(&value->desc, &pkt->service_descr, sizeof(struct GNUNET_vpn_service_descriptor));
 505
 506         memset(value->additional_ports, 0, 8192);
 507
 508         memcpy(&value->hash, &key, sizeof(GNUNET_HashCode));
 509
 510         if (GNUNET_NO ==
 511             GNUNET_CONTAINER_multihashmap_contains (hashmap, &key))
 512           {
 513             GNUNET_CONTAINER_multihashmap_put (hashmap, &key, value,
 514                                                GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
 515
 516             value->heap_node = GNUNET_CONTAINER_heap_insert (heap, value,
 517                                                              GNUNET_TIME_absolute_get ().abs_value);
 518             if (GNUNET_CONTAINER_heap_get_size(heap) > max_mappings)
 519               GNUNET_SCHEDULER_add_now(collect_mappings, NULL);
 520           }
 521         else
 522           GNUNET_free(value);
 523
 524
 525         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 526
 527         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 528
 529       }
 530     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_REV)
 531       {
 532         GNUNET_HashCode key;
 533         memset(&key, 0, sizeof key);
 534         unsigned char* k = (unsigned char*)&key;
 535         unsigned char* s = pkt->data+12;
 536         int i = 0;
 537         /* Whoever designed the reverse IPv6-lookup is batshit insane */
 538         for (i = 0; i < 16; i++)
 539           {
 540             unsigned char c1 = s[(4*i)+1];
 541             unsigned char c2 = s[(4*i)+3];
 542             if (c1 <= '9')
 543               k[i] = c1 - '0';
 544             else
 545               k[i] = c1 - 87; /* 87 is the difference between 'a' and 10 */
 546             if (c2 <= '9')
 547               k[i] += 16*(c2 - '0');
 548             else
 549               k[i] += 16*(c2 - 87);
 550           }
 551
 552         struct map_entry* map_entry = GNUNET_CONTAINER_multihashmap_get(hashmap, &key);
 553         uint16_t offset = ntohs(pkt->addroffset);
 554
 555         if (map_entry == NULL)
 556           {
 557             GNUNET_free(pkt);
 558             return;
 559           }
 560
 561         GNUNET_CONTAINER_heap_update_cost (heap, map_entry->heap_node,
 562                                            GNUNET_TIME_absolute_get ().abs_value);
 563
 564
 565         unsigned short namelen = htons(map_entry->namelen);
 566         char* name = (char*)(map_entry + 1);
 567
 568         list = GNUNET_malloc(2*sizeof(struct answer_packet_list*) + offset + 2 + ntohs(namelen));
 569
 570         struct answer_packet* rpkt = &list->pkt;
 571
 572         /* The offset points to the first byte belonging to the address */
 573         memcpy(rpkt, pkt, offset - 1);
 574
 575         rpkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 576         rpkt->hdr.size = ntohs(offset + 2 + ntohs(namelen));
 577
 578         memcpy(((char*)rpkt)+offset, &namelen, 2);
 579         memcpy(((char*)rpkt)+offset+2, name, ntohs(namelen));
 580
 581       }
 582     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_IP)
 583       {
 584         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 585         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 586       }
 587     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_REMOTE_AAAA)
 588       {
 589         pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 590
 591         GNUNET_HashCode key;
 592         memset(&key, 0, sizeof(GNUNET_HashCode));
 593
 594         unsigned char* c = ((unsigned char*)pkt)+ntohs(pkt->addroffset);
 595         new_ip6addr_remote(c, pkt->addr, pkt->addrsize);
 596         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "New mapping to %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
 597                    c[0],
 598                    c[1],
 599                    c[2],
 600                    c[3],
 601                    c[4],
 602                    c[5],
 603                    c[6],
 604                    c[7],
 605                    c[8],
 606                    c[9],
 607                    c[10],
 608                    c[11],
 609                    c[12],
 610                    c[13],
 611                    c[14],
 612                    c[15]);
 613         unsigned char* k = (unsigned char*)&key;
 614         /*
 615          * Copy the newly generated ip-address to the key backwards (as only the first part is used in the hash-table)
 616          */
 617         unsigned int i;
 618         for (i = 0; i < 16; i++)
 619             k[15-i] = c[i];
 620
 621         uint16_t namelen = strlen((char*)pkt->data+12)+1;
 622
 623         struct map_entry* value = GNUNET_malloc(sizeof(struct map_entry) + namelen);
 624         char* name = (char*)(value +1);
 625
 626         value->namelen = namelen;
 627         memcpy(name, pkt->data+12, namelen);
 628
 629         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Setting addrlen to %d\n", pkt->addrsize);
 630         value->addrlen = pkt->addrsize;
 631         memcpy(&value->addr, &pkt->addr, pkt->addrsize);
 632         memset(value->additional_ports, 0, 8192);
 633
 634         memcpy(&value->hash, &key, sizeof(GNUNET_HashCode));
 635
 636         if (GNUNET_NO ==
 637             GNUNET_CONTAINER_multihashmap_contains (hashmap, &key))
 638           {
 639             GNUNET_CONTAINER_multihashmap_put (hashmap, &key, value,
 640                                                GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
 641             value->heap_node = GNUNET_CONTAINER_heap_insert (heap, value,
 642                                                              GNUNET_TIME_absolute_get ().abs_value);
 643             if (GNUNET_CONTAINER_heap_get_size(heap) > max_mappings)
 644               GNUNET_SCHEDULER_add_now(collect_mappings, NULL);
 645           }
 646         else
 647           GNUNET_free(value);
 648
 649         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 650
 651         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 652       }
 653     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_REMOTE_A)
 654       {
 655         pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 656
 657         GNUNET_HashCode key;
 658         memset(&key, 0, sizeof(GNUNET_HashCode));
 659
 660         unsigned char* c = ((unsigned char*)pkt)+ntohs(pkt->addroffset);
 661         new_ip4addr_remote(c, pkt->addr, pkt->addrsize);
 662         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "New mapping to %d.%d.%d.%d\n",
 663                    c[0],
 664                    c[1],
 665                    c[2],
 666                    c[3]);
 667         unsigned char* k = (unsigned char*)&key;
 668         /*
 669          * Copy the newly generated ip-address to the key backwards (as only the first part is used in the hash-table)
 670          */
 671         unsigned int i;
 672         for (i = 0; i < 4; i++)
 673             k[3-i] = c[i];
 674
 675         uint16_t namelen = strlen((char*)pkt->data+12)+1;
 676
 677         struct map_entry* value = GNUNET_malloc(sizeof(struct map_entry) + namelen);
 678         char* name = (char*)(value +1);
 679
 680         value->namelen = namelen;
 681         memcpy(name, pkt->data+12, namelen);
 682
 683         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Setting addrlen to %d\n", pkt->addrsize);
 684         value->addrlen = pkt->addrsize;
 685         memcpy(&value->addr, &pkt->addr, pkt->addrsize);
 686         memset(value->additional_ports, 0, 8192);
 687
 688         memcpy(&value->hash, &key, sizeof(GNUNET_HashCode));
 689
 690         if (GNUNET_NO ==
 691             GNUNET_CONTAINER_multihashmap_contains (hashmap, &key))
 692           {
 693             GNUNET_CONTAINER_multihashmap_put (hashmap, &key, value,
 694                                                GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
 695             value->heap_node = GNUNET_CONTAINER_heap_insert (heap, value,
 696                                                              GNUNET_TIME_absolute_get ().abs_value);
 697             GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Mapping is saved in the hashmap with key %08x.\n",
 698                        *((uint32_t*)(&key)));
 699             if (GNUNET_CONTAINER_heap_get_size(heap) > max_mappings)
 700               GNUNET_SCHEDULER_add_now(collect_mappings, NULL);
 701           }
 702         else
 703           GNUNET_free(value);
 704
 705         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 706
 707         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 708       }
 709     else
 710       {
 711         GNUNET_break(0);
 712         GNUNET_free(pkt);
 713         return;
 714       }
 715
 716     GNUNET_free(pkt);
 717
 718     GNUNET_CONTAINER_DLL_insert_after(answer_proc_head, answer_proc_tail, answer_proc_tail, list);
 719
 720     schedule_helper_write(GNUNET_TIME_UNIT_FOREVER_REL, NULL);
 721
 722     return;
 723 }
 724
 725 /**
 726  * Sets a bit active in a bitArray.
 727  *
 728  * @param bitArray memory area to set the bit in
 729  * @param bitIdx which bit to set
 730  */
 731 void
 732 setBit (char *bitArray, unsigned int bitIdx)
 733 {
 734   size_t arraySlot;
 735   unsigned int targetBit;
 736
 737   arraySlot = bitIdx / 8;
 738   targetBit = (1L << (bitIdx % 8));
 739   bitArray[arraySlot] |= targetBit;
 740 }
 741
 742 /**
 743  * Clears a bit from bitArray.
 744  *
 745  * @param bitArray memory area to set the bit in
 746  * @param bitIdx which bit to unset
 747  */
 748 void
 749 clearBit (char *bitArray, unsigned int bitIdx)
 750 {
 751   size_t slot;
 752   unsigned int targetBit;
 753
 754   slot = bitIdx / 8;
 755   targetBit = (1L << (bitIdx % 8));
 756   bitArray[slot] = bitArray[slot] & (~targetBit);
 757 }
 758
 759 /**
 760  * Checks if a bit is active in the bitArray
 761  *
 762  * @param bitArray memory area to set the bit in
 763  * @param bitIdx which bit to test
 764  * @return GNUNET_YES if the bit is set, GNUNET_NO if not.
 765  */
 766 int
 767 testBit (char *bitArray, unsigned int bitIdx)
 768 {
 769   size_t slot;
 770   unsigned int targetBit;
 771
 772   slot = bitIdx / 8;
 773   targetBit = (1L << (bitIdx % 8));
 774   if (bitArray[slot] & targetBit)
 775     return GNUNET_YES;
 776   else
 777     return GNUNET_NO;
 778 }
 779
 780 /**
 781  * @brief Add the port to the list of additional ports in the map_entry
 782  *
 783  * @param me the map_entry
 784  * @param port the port in host-byte-order
 785  */
 786 static void
 787 add_additional_port (struct map_entry *me, uint16_t port)
 788 {
 789   setBit(me->additional_ports, port);
 790 }
 791
 792 static int
 793 receive_udp_back (void *cls
 794                   __attribute__ ((unused)), struct GNUNET_MESH_Tunnel *tunnel,
 795                   void **tunnel_ctx __attribute__ ((unused)),
 796                   const struct GNUNET_PeerIdentity *sender __attribute__ ((unused)),
 797                   const struct GNUNET_MessageHeader *message,
 798                   const struct GNUNET_TRANSPORT_ATS_Information *atsi __attribute__ ((unused)))
 799 {
 800   GNUNET_HashCode *desc = (GNUNET_HashCode *) (message + 1);
 801   struct remote_addr *s = (struct remote_addr *) desc;
 802   struct udp_pkt *pkt = (struct udp_pkt *) (desc + 1);
 803   const struct GNUNET_PeerIdentity *other = GNUNET_MESH_get_peer (tunnel);
 804
 805   if (16 == s->addrlen)
 806     {
 807       size_t size =
 808         sizeof (struct ip6_udp) + ntohs (pkt->len) - 1 - sizeof (struct udp_pkt);
 809
 810       struct ip6_udp *pkt6 = alloca (size);
 811
 812       GNUNET_assert (pkt6 != NULL);
 813
 814       if (ntohs (message->type) == GNUNET_MESSAGE_TYPE_SERVICE_UDP_BACK)
 815         new_ip6addr (pkt6->ip6_hdr.sadr, &other->hashPubKey, desc);
 816       else
 817         new_ip6addr_remote (pkt6->ip6_hdr.sadr, s->addr, s->addrlen);
 818
 819       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 820                   "Relaying calc:%d gnu:%d udp:%d bytes!\n", size,
 821                   ntohs (message->size), ntohs (pkt->len));
 822
 823       pkt6->shdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
 824       pkt6->shdr.size = htons (size);
 825
 826       pkt6->tun.flags = 0;
 827       pkt6->tun.type = htons (0x86dd);
 828
 829       pkt6->ip6_hdr.version = 6;
 830       pkt6->ip6_hdr.tclass_h = 0;
 831       pkt6->ip6_hdr.tclass_l = 0;
 832       pkt6->ip6_hdr.flowlbl = 0;
 833       pkt6->ip6_hdr.paylgth = pkt->len;
 834       pkt6->ip6_hdr.nxthdr = 0x11;
 835       pkt6->ip6_hdr.hoplmt = 0xff;
 836
 837       {
 838         char *ipv6addr;
 839         GNUNET_assert (GNUNET_OK ==
 840                        GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
 841                                                               "IPV6ADDR",
 842                                                               &ipv6addr));
 843         inet_pton (AF_INET6, ipv6addr, pkt6->ip6_hdr.dadr);
 844         GNUNET_free (ipv6addr);
 845       }
 846       memcpy (&pkt6->udp_hdr, pkt, ntohs (pkt->len));
 847
 848       GNUNET_HashCode *key = address6_mapping_exists (pkt6->ip6_hdr.sadr);
 849       GNUNET_assert (key != NULL);
 850
 851       struct map_entry *me = GNUNET_CONTAINER_multihashmap_get (hashmap, key);
 852       GNUNET_CONTAINER_heap_update_cost (heap, me->heap_node,
 853                                          GNUNET_TIME_absolute_get ().
 854                                          abs_value);
 855
 856       GNUNET_free (key);
 857
 858       GNUNET_assert (me != NULL);
 859       if (ntohs (message->type) == GNUNET_MESSAGE_TYPE_SERVICE_UDP_BACK)
 860         {
 861           GNUNET_assert (me->desc.
 862                          service_type & htonl (GNUNET_DNS_SERVICE_TYPE_UDP));
 863           if (!port_in_ports (me->desc.ports, pkt6->udp_hdr.spt)
 864               && !testBit (me->additional_ports, ntohs (pkt6->udp_hdr.spt)))
 865             {
 866               add_additional_port (me, ntohs (pkt6->udp_hdr.spt));
 867             }
 868         }
 869
 870       pkt6->udp_hdr.crc = 0;
 871       uint32_t sum = 0;
 872       sum =
 873         calculate_checksum_update (sum, (uint16_t *) & pkt6->ip6_hdr.sadr,
 874                                    16);
 875       sum =
 876         calculate_checksum_update (sum, (uint16_t *) & pkt6->ip6_hdr.dadr,
 877                                    16);
 878       uint32_t tmp = (pkt6->udp_hdr.len & 0xffff);
 879       sum = calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
 880       tmp = htons (((pkt6->ip6_hdr.nxthdr & 0x00ff)));
 881       sum = calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
 882
 883       sum =
 884         calculate_checksum_update (sum, (uint16_t *) & pkt6->udp_hdr,
 885                                    ntohs (pkt->len));
 886       pkt6->udp_hdr.crc = calculate_checksum_end (sum);
 887
 888       write_to_helper (pkt6, size);
 889     }
 890   else
 891     {
 892       size_t size =
 893         sizeof (struct ip_udp) + ntohs (pkt->len) - 1 - sizeof (struct udp_pkt);
 894
 895       struct ip_udp *pkt4 = alloca (size);
 896
 897       GNUNET_assert (pkt4 != NULL);
 898
 899       GNUNET_assert (ntohs (message->type) == GNUNET_MESSAGE_TYPE_REMOTE_UDP_BACK);
 900       uint32_t sadr;
 901       new_ip4addr_remote ((unsigned char*)&sadr, s->addr, s->addrlen);
 902       pkt4->ip_hdr.sadr = sadr;
 903
 904       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 905                   "Relaying calc:%d gnu:%d udp:%d bytes!\n", size,
 906                   ntohs (message->size), ntohs (pkt->len));
 907
 908       pkt4->shdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
 909       pkt4->shdr.size = htons (size);
 910
 911       pkt4->tun.flags = 0;
 912       pkt4->tun.type = htons (0x0800);
 913
 914       pkt4->ip_hdr.version = 4;
 915       pkt4->ip_hdr.hdr_lngth = 5;
 916       pkt4->ip_hdr.diff_serv = 0;
 917       pkt4->ip_hdr.tot_lngth = htons (20 + ntohs(pkt->len));
 918       pkt4->ip_hdr.ident = 0;
 919       pkt4->ip_hdr.flags = 0;
 920       pkt4->ip_hdr.frag_off = 0;
 921       pkt4->ip_hdr.ttl = 255;
 922       pkt4->ip_hdr.proto = 0x11;
 923       pkt4->ip_hdr.chks = 0;        /* Will be calculated later */
 924
 925       {
 926         char *ipv4addr;
 927         uint32_t dadr;
 928         GNUNET_assert (GNUNET_OK ==
 929                        GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
 930                                                               "IPV4ADDR",
 931                                                               &ipv4addr));
 932         inet_pton (AF_INET, ipv4addr, &dadr);
 933         GNUNET_free (ipv4addr);
 934         pkt4->ip_hdr.dadr = dadr;
 935       }
 936       memcpy (&pkt4->udp_hdr, pkt, ntohs (pkt->len));
 937
 938       GNUNET_HashCode *key = address4_mapping_exists (pkt4->ip_hdr.sadr);
 939       GNUNET_assert (key != NULL);
 940
 941       struct map_entry *me = GNUNET_CONTAINER_multihashmap_get (hashmap, key);
 942       GNUNET_CONTAINER_heap_update_cost (heap, me->heap_node,
 943                                          GNUNET_TIME_absolute_get ().
 944                                          abs_value);
 945
 946       GNUNET_free (key);
 947
 948       GNUNET_assert (me != NULL);
 949
 950       pkt4->udp_hdr.crc = 0; /* Optional for IPv4 */
 951
 952       pkt4->ip_hdr.chks =
 953         calculate_ip_checksum ((uint16_t *) & pkt4->ip_hdr, 5 * 4);
 954
 955       write_to_helper (pkt4, size);
 956     }
 957
 958   return GNUNET_OK;
 959 }
 960
 961 static int
 962 receive_tcp_back (void *cls __attribute__((unused)), struct GNUNET_MESH_Tunnel* tunnel,
 963                   void **tunnel_ctx __attribute__((unused)),
 964                   const struct GNUNET_PeerIdentity *sender __attribute__((unused)),
 965                   const struct GNUNET_MessageHeader *message,
 966                   const struct GNUNET_TRANSPORT_ATS_Information *atsi __attribute__((unused)))
 967 {
 968   GNUNET_HashCode *desc = (GNUNET_HashCode *) (message + 1);
 969   struct remote_addr *s = (struct remote_addr *) desc;
 970   struct tcp_pkt *pkt = (struct tcp_pkt *) (desc + 1);
 971   const struct GNUNET_PeerIdentity *other = GNUNET_MESH_get_peer (tunnel);
 972
 973   size_t pktlen =
 974     ntohs (message->size) - sizeof (struct GNUNET_MessageHeader) -
 975     sizeof (GNUNET_HashCode);
 976
 977   if (s->addrlen == 16)
 978     {
 979       size_t size = pktlen + sizeof (struct ip6_tcp) - 1;
 980
 981       struct ip6_tcp *pkt6 = alloca (size);
 982       memset (pkt6, 0, size);
 983
 984       GNUNET_assert (pkt6 != NULL);
 985
 986       if (ntohs (message->type) == GNUNET_MESSAGE_TYPE_SERVICE_TCP_BACK)
 987         new_ip6addr (pkt6->ip6_hdr.sadr, &other->hashPubKey, desc);
 988       else
 989         new_ip6addr_remote (pkt6->ip6_hdr.sadr, s->addr, s->addrlen);
 990
 991       pkt6->shdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
 992       pkt6->shdr.size = htons (size);
 993
 994       pkt6->tun.flags = 0;
 995       pkt6->tun.type = htons (0x86dd);
 996
 997       pkt6->ip6_hdr.version = 6;
 998       pkt6->ip6_hdr.tclass_h = 0;
 999       pkt6->ip6_hdr.tclass_l = 0;
1000       pkt6->ip6_hdr.flowlbl = 0;
1001       pkt6->ip6_hdr.paylgth = htons (pktlen);
1002       pkt6->ip6_hdr.nxthdr = 0x06;
1003       pkt6->ip6_hdr.hoplmt = 0xff;
1004
1005       {
1006         char *ipv6addr;
1007         GNUNET_assert (GNUNET_OK ==
1008                        GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
1009                                                               "IPV6ADDR",
1010                                                               &ipv6addr));
1011         inet_pton (AF_INET6, ipv6addr, pkt6->ip6_hdr.dadr);
1012         GNUNET_free (ipv6addr);
1013       }
1014       memcpy (&pkt6->tcp_hdr, pkt, pktlen);
1015
1016       GNUNET_HashCode *key = address6_mapping_exists (pkt6->ip6_hdr.sadr);
1017       GNUNET_assert (key != NULL);
1018
1019       struct map_entry *me = GNUNET_CONTAINER_multihashmap_get (hashmap, key);
1020       GNUNET_CONTAINER_heap_update_cost (heap, me->heap_node,
1021                                          GNUNET_TIME_absolute_get ().
1022                                          abs_value);
1023
1024       GNUNET_free (key);
1025
1026       GNUNET_assert (me != NULL);
1027       if (ntohs (message->type) == GNUNET_MESSAGE_TYPE_SERVICE_UDP_BACK)
1028         GNUNET_assert (me->desc.
1029                        service_type & htonl (GNUNET_DNS_SERVICE_TYPE_TCP));
1030
1031       pkt6->tcp_hdr.crc = 0;
1032       uint32_t sum = 0;
1033       uint32_t tmp;
1034       sum =
1035         calculate_checksum_update (sum, (uint16_t *) & pkt6->ip6_hdr.sadr,
1036                                    16);
1037       sum =
1038         calculate_checksum_update (sum, (uint16_t *) & pkt6->ip6_hdr.dadr,
1039                                    16);
1040       tmp = htonl (pktlen);
1041       sum = calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
1042       tmp = htonl (((pkt6->ip6_hdr.nxthdr & 0x000000ff)));
1043       sum = calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
1044
1045       sum =
1046         calculate_checksum_update (sum, (uint16_t *) & pkt6->tcp_hdr,
1047                                    ntohs (pkt6->ip6_hdr.paylgth));
1048       pkt6->tcp_hdr.crc = calculate_checksum_end (sum);
1049
1050       write_to_helper (pkt6, size);
1051     }
1052   else
1053     {
1054       size_t size = pktlen + sizeof (struct ip_tcp) - 1;
1055
1056       struct ip_tcp *pkt4 = alloca (size);
1057       GNUNET_assert (pkt4 != NULL);
1058       memset (pkt4, 0, size);
1059
1060       GNUNET_assert (ntohs (message->type) == GNUNET_MESSAGE_TYPE_REMOTE_TCP_BACK);
1061       uint32_t sadr;
1062       new_ip4addr_remote ((unsigned char*)&sadr, s->addr, s->addrlen);
1063       pkt4->ip_hdr.sadr = sadr;
1064
1065       pkt4->shdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
1066       pkt4->shdr.size = htons (size);
1067
1068       pkt4->tun.flags = 0;
1069       pkt4->tun.type = htons (0x0800);
1070
1071       pkt4->ip_hdr.version = 4;
1072       pkt4->ip_hdr.hdr_lngth = 5;
1073       pkt4->ip_hdr.diff_serv = 0;
1074       pkt4->ip_hdr.tot_lngth = htons (20 + pktlen);
1075       pkt4->ip_hdr.ident = 0;
1076       pkt4->ip_hdr.flags = 0;
1077       pkt4->ip_hdr.frag_off = 0;
1078       pkt4->ip_hdr.ttl = 255;
1079       pkt4->ip_hdr.proto = 0x06;
1080       pkt4->ip_hdr.chks = 0;        /* Will be calculated later */
1081
1082       {
1083         char *ipv4addr;
1084         uint32_t dadr;
1085         GNUNET_assert (GNUNET_OK ==
1086                        GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
1087                                                               "IPV4ADDR",
1088                                                               &ipv4addr));
1089         inet_pton (AF_INET, ipv4addr, &dadr);
1090         GNUNET_free (ipv4addr);
1091         pkt4->ip_hdr.dadr = dadr;
1092       }
1093
1094       memcpy (&pkt4->tcp_hdr, pkt, pktlen);
1095
1096       GNUNET_HashCode *key = address4_mapping_exists (pkt4->ip_hdr.sadr);
1097       GNUNET_assert (key != NULL);
1098
1099       struct map_entry *me = GNUNET_CONTAINER_multihashmap_get (hashmap, key);
1100       GNUNET_CONTAINER_heap_update_cost (heap, me->heap_node,
1101                                          GNUNET_TIME_absolute_get ().
1102                                          abs_value);
1103
1104       GNUNET_free (key);
1105
1106       GNUNET_assert (me != NULL);
1107       pkt4->tcp_hdr.crc = 0;
1108       uint32_t sum = 0;
1109       uint32_t tmp;
1110       tmp = pkt4->ip_hdr.sadr;
1111       sum =
1112         calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
1113       tmp = pkt4->ip_hdr.dadr;
1114       sum =
1115         calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
1116
1117       tmp = (0x06 << 16) | (0xffff & pktlen);
1118
1119       tmp = htonl(tmp);
1120
1121       sum = calculate_checksum_update (sum, (uint16_t *) & tmp, 4);
1122
1123       sum =
1124         calculate_checksum_update (sum, (uint16_t *) & pkt4->tcp_hdr, pktlen);
1125       pkt4->tcp_hdr.crc = calculate_checksum_end (sum);
1126
1127       pkt4->ip_hdr.chks =
1128         calculate_ip_checksum ((uint16_t *) & pkt4->ip_hdr, 5 * 4);
1129
1130       write_to_helper (pkt4, size);
1131     }
1132
1133   return GNUNET_OK;
1134 }
1135
1136 /**
1137  * Main function that will be run by the scheduler.
1138  *
1139  * @param cls closure
1140  * @param args remaining command-line arguments
1141  * @param cfgfile name of the configuration file used (for saving, can be NULL!)
1142  * @param cfg_ configuration
1143  */
1144 static void
1145 run (void *cls,
1146      char *const *args __attribute__((unused)),
1147      const char *cfgfilep __attribute__((unused)),
1148      const struct GNUNET_CONFIGURATION_Handle *cfg_)
1149 {
1150     static const struct GNUNET_MESH_MessageHandler handlers[] = {
1151           {receive_udp_back, GNUNET_MESSAGE_TYPE_SERVICE_UDP_BACK, 0},
1152           {receive_tcp_back, GNUNET_MESSAGE_TYPE_SERVICE_TCP_BACK, 0},
1153           {receive_udp_back, GNUNET_MESSAGE_TYPE_REMOTE_UDP_BACK, 0},
1154           {receive_tcp_back, GNUNET_MESSAGE_TYPE_REMOTE_TCP_BACK, 0},
1155           {NULL, 0, 0}
1156     };
1157
1158     static const GNUNET_MESH_ApplicationType types[] = {
1159         GNUNET_APPLICATION_TYPE_END
1160     };
1161
1162     mesh_handle = GNUNET_MESH_connect(cfg_,
1163                                       NULL,
1164                                       NULL,
1165                                       handlers,
1166                                       types);
1167     cfg = cfg_;
1168     restart_hijack = 0;
1169     hashmap = GNUNET_CONTAINER_multihashmap_create(65536);
1170     heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
1171     GNUNET_CONFIGURATION_get_value_number (cfg, "vpn", "MAX_MAPPINGg",
1172                                            &max_mappings);
1173     udp_connections = GNUNET_CONTAINER_multihashmap_create(65536);
1174     conn_task = GNUNET_SCHEDULER_add_now (connect_to_service_dns, NULL);
1175     shs_task = GNUNET_SCHEDULER_add_after (conn_task, start_helper_and_schedule, NULL);
1176     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_FOREVER_REL, &cleanup, cls);
1177 }
1178
1179 /**
1180  * The main function to obtain template from gnunetd.
1181  *
1182  * @param argc number of arguments from the command line
1183  * @param argv command line arguments
1184  * @return 0 ok, 1 on error
1185  */
1186 int
1187 main (int argc, char *const *argv) {
1188     static const struct GNUNET_GETOPT_CommandLineOption options[] = {
1189         GNUNET_GETOPT_OPTION_END
1190     };
1191
1192     return (GNUNET_OK ==
1193             GNUNET_PROGRAM_run (argc,
1194                                 argv,
1195                                 "vpn",
1196                                 gettext_noop ("help text"),
1197                                 options, &run, NULL)) ? ret : 1;
1198 }
1199
1200 /* end of gnunet-daemon-vpn.c */
1201