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_os_lib.h"
  30 #include "gnunet-vpn-helper-p.h"
  31 #include "gnunet-vpn-packet.h"
  32 #include "gnunet-vpn-pretty-print.h"
  33 #include "gnunet_common.h"
  34 #include "gnunet_protocols.h"
  35 #include "gnunet_server_lib.h"
  36 #include "gnunet-service-dns-p.h"
  37 #include "gnunet_core_service.h"
  38 #include "gnunet_client_lib.h"
  39 #include "gnunet_container_lib.h"
  40 #include "block_dns.h"
  41
  42 /**
  43  * Final status code.
  44  */
  45 static int ret;
  46
  47 /**
  48  * The configuration to use
  49  */
  50 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  51
  52 /**
  53  * PipeHandle to receive data from the helper
  54  */
  55 static struct GNUNET_DISK_PipeHandle* helper_in;
  56
  57 /**
  58  * PipeHandle to send data to the helper
  59  */
  60 static struct GNUNET_DISK_PipeHandle* helper_out;
  61
  62 /**
  63  * FileHandle to receive data from the helper
  64  */
  65 static const struct GNUNET_DISK_FileHandle* fh_from_helper;
  66
  67 /**
  68  * FileHandle to send data to the helper
  69  */
  70 static const struct GNUNET_DISK_FileHandle* fh_to_helper;
  71
  72 /**
  73  * The Message-Tokenizer that tokenizes the messages comming from the helper
  74  */
  75 static struct GNUNET_SERVER_MessageStreamTokenizer* mst;
  76
  77 /**
  78  * The connection to the service-dns
  79  */
  80 static struct GNUNET_CLIENT_Connection *dns_connection;
  81
  82 /**
  83  * A flag to show that the service-dns has to rehijack the outbound dns-packets
  84  *
  85  * This gets set when the helper restarts as the routing-tables are flushed when
  86  * the interface vanishes.
  87  */
  88 static unsigned char restart_hijack;
  89
  90 /**
  91  * The process id of the helper
  92  */
  93 static struct GNUNET_OS_Process *helper_proc;
  94
  95 /**
  96  * a list of outgoing dns-query-packets
  97  */
  98 static struct query_packet_list *head;
  99
 100 /**
 101  * The last element of the list of outgoing dns-query-packets
 102  */
 103 static struct query_packet_list *tail;
 104
 105 /**
 106  * A list of processed dns-responses.
 107  *
 108  * "processed" means that the packet is complete and can be sent out via udp
 109  * directly
 110  */
 111 static struct answer_packet_list *answer_proc_head;
 112
 113 /**
 114  * The last element of the list of processed dns-responses.
 115  */
 116 static struct answer_packet_list *answer_proc_tail;
 117
 118 /**
 119  * The hashmap containing the mappings from ipv6-addresses to gnunet-descriptors
 120  */
 121 static struct GNUNET_CONTAINER_MultiHashMap* hashmap;
 122
 123 /**
 124  * This hashmap contains the mapping from peer, service-descriptor,
 125  * source-port and destination-port to a socket
 126  */
 127 static struct GNUNET_CONTAINER_MultiHashMap *udp_connections;
 128
 129 /**
 130  * The handle to core
 131  */
 132 static struct GNUNET_CORE_Handle *core_handle;
 133
 134 struct map_entry {
 135     struct GNUNET_vpn_service_descriptor desc;
 136     uint16_t namelen;
 137     /**
 138      * In DNS-Format!
 139      */
 140     char name[1];
 141 };
 142
 143 static void helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx);
 144 static void dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg);
 145
 146 /**
 147  * Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages
 148  * to the service-dns
 149  * {{{
 150  */
 151 static size_t
 152 send_query(void* cls, size_t size, void* buf) {
 153     size_t len;
 154     /*
 155      * Send the rehijack-message
 156      */
 157     if (restart_hijack == 1)
 158       {
 159         restart_hijack = 0;
 160         /*
 161          * The message is just a header
 162          */
 163         GNUNET_assert(sizeof(struct GNUNET_MessageHeader) <= size);
 164         struct GNUNET_MessageHeader* hdr = buf;
 165         len = sizeof(struct GNUNET_MessageHeader);
 166         hdr->size = htons(len);
 167         hdr->type = htons(GNUNET_MESSAGE_TYPE_REHIJACK);
 168       }
 169     else
 170       {
 171         struct query_packet_list* query = head;
 172         len = ntohs(query->pkt.hdr.size);
 173
 174         GNUNET_assert(len <= size);
 175
 176         memcpy(buf, &query->pkt.hdr, len);
 177
 178         GNUNET_CONTAINER_DLL_remove (head, tail, query);
 179
 180         GNUNET_free(query);
 181       }
 182
 183     /*
 184      * Check whether more data is to be sent
 185      */
 186     if (head != NULL)
 187       {
 188         GNUNET_CLIENT_notify_transmit_ready(dns_connection, ntohs(head->pkt.hdr.size), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 189       }
 190     else if (restart_hijack == 1)
 191       {
 192         GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 193       }
 194
 195     return len;
 196 }
 197 /* }}} */
 198
 199 /**
 200  * Function scheduled as very last function, cleans up after us
 201  *{{{
 202  */
 203 static void
 204 cleanup(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 205     GNUNET_assert (0 != (tskctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN));
 206
 207     /* stop the helper */
 208     if (helper_proc != NULL)
 209       {
 210         GNUNET_OS_process_kill (helper_proc, SIGTERM);
 211         GNUNET_OS_process_wait (helper_proc);
 212         GNUNET_OS_process_close (helper_proc);
 213         helper_proc = NULL;
 214       }
 215
 216     /* close the connection to the service-dns */
 217     if (dns_connection != NULL)
 218       {
 219         GNUNET_CLIENT_disconnect (dns_connection, GNUNET_NO);
 220         dns_connection = NULL;
 221       }
 222
 223     if (core_handle != NULL)
 224       {
 225         GNUNET_CORE_disconnect(core_handle);
 226         core_handle = NULL;
 227       }
 228 }
 229 /*}}}*/
 230
 231 /**
 232  * Start the helper-process
 233  * {{{
 234  */
 235 static void
 236 start_helper_and_schedule(void *cls,
 237                           const struct GNUNET_SCHEDULER_TaskContext *tc) {
 238     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 239       return;
 240
 241     helper_in = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_YES, GNUNET_NO);
 242     helper_out = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_NO, GNUNET_YES);
 243
 244     if (helper_in == NULL || helper_out == NULL) return;
 245
 246     helper_proc = GNUNET_OS_start_process(helper_in, helper_out, "gnunet-helper-vpn", "gnunet-helper-vpn", NULL);
 247
 248     fh_from_helper = GNUNET_DISK_pipe_handle (helper_out, GNUNET_DISK_PIPE_END_READ);
 249     fh_to_helper = GNUNET_DISK_pipe_handle (helper_in, GNUNET_DISK_PIPE_END_WRITE);
 250
 251     GNUNET_DISK_pipe_close_end(helper_out, GNUNET_DISK_PIPE_END_WRITE);
 252     GNUNET_DISK_pipe_close_end(helper_in, GNUNET_DISK_PIPE_END_READ);
 253
 254     /* Tell the dns-service to rehijack the dns-port
 255      * The routing-table gets flushed if an interface disappears.
 256      */
 257     restart_hijack = 1;
 258     GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 259
 260     GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 261 }
 262 /*}}}*/
 263
 264 /**
 265  * Restart the helper-process
 266  * {{{
 267  */
 268 static void
 269 restart_helper(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 270     // Kill the helper
 271     GNUNET_OS_process_kill (helper_proc, SIGKILL);
 272     GNUNET_OS_process_wait (helper_proc);
 273     GNUNET_OS_process_close (helper_proc);
 274     helper_proc = NULL;
 275
 276     GNUNET_DISK_pipe_close(helper_in);
 277     GNUNET_DISK_pipe_close(helper_out);
 278
 279     /* Restart the helper */
 280     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, start_helper_and_schedule, NULL);
 281 }
 282 /*}}}*/
 283
 284 /**
 285  * Read from the helper-process
 286  * {{{
 287  */
 288 static void
 289 helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 290     /* no message can be bigger then 64k */
 291     char buf[65535];
 292
 293     if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 294       return;
 295
 296     int t = GNUNET_DISK_file_read(fh_from_helper, &buf, 65535);
 297
 298     /* On read-error, restart the helper */
 299     if (t<=0) {
 300         GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Read error for header from vpn-helper: %m\n");
 301         GNUNET_SCHEDULER_add_now(restart_helper, cls);
 302         return;
 303     }
 304
 305     /* FIXME */ GNUNET_SERVER_mst_receive(mst, NULL, buf, t, 0, 0);
 306
 307     GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 308 }
 309 /*}}}*/
 310
 311 static uint32_t calculate_checksum_update(uint32_t sum, uint16_t *hdr, short len) {
 312     for(; len >= 2; len -= 2)
 313       sum += *(hdr++);
 314     if (len == 1)
 315       sum += *((unsigned char*)hdr);
 316     return sum;
 317 }
 318
 319 static uint16_t calculate_checksum_end(uint32_t sum) {
 320     while (sum >> 16)
 321       sum = (sum >> 16) + (sum & 0xFFFF);
 322
 323     return ~sum;
 324 }
 325
 326 /**
 327  * Calculate the checksum of an IPv4-Header
 328  */
 329 static uint16_t
 330 calculate_ip_checksum(uint16_t* hdr, short len) {
 331     uint32_t sum = calculate_checksum_update(0, hdr, len);
 332     return calculate_checksum_end(sum);
 333 }
 334
 335 /**
 336  * Send an dns-answer-packet to the helper
 337  */
 338 static void
 339 helper_write(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 340     if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 341       return;
 342
 343     struct answer_packet_list* ans = answer_proc_head;
 344     size_t len = ntohs(ans->pkt.hdr.size);
 345
 346     GNUNET_assert(ans->pkt.subtype == GNUNET_DNS_ANSWER_TYPE_IP);
 347
 348     GNUNET_assert (20 == sizeof (struct ip_hdr));
 349     GNUNET_assert (8 == sizeof (struct udp_pkt));
 350     size_t data_len = len - sizeof(struct answer_packet) + 1;
 351     size_t net_len = sizeof(struct ip_hdr) + sizeof(struct udp_dns) + data_len;
 352     size_t pkt_len = sizeof(struct GNUNET_MessageHeader) + sizeof(struct pkt_tun) + net_len;
 353
 354     struct ip_udp_dns* pkt = alloca(pkt_len);
 355     memset(pkt, 0, pkt_len);
 356
 357     /* set the gnunet-header */
 358     pkt->shdr.size = htons(pkt_len);
 359     pkt->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 360
 361     /* set the tun-header (no flags and ethertype of IPv4) */
 362     pkt->tun.flags = 0;
 363     pkt->tun.type = htons(0x0800);
 364
 365     /* set the ip-header */
 366     pkt->ip_hdr.version = 4;
 367     pkt->ip_hdr.hdr_lngth = 5;
 368     pkt->ip_hdr.diff_serv = 0;
 369     pkt->ip_hdr.tot_lngth = htons(net_len);
 370     pkt->ip_hdr.ident = 0;
 371     pkt->ip_hdr.flags = 0;
 372     pkt->ip_hdr.frag_off = 0;
 373     pkt->ip_hdr.ttl = 255;
 374     pkt->ip_hdr.proto = 0x11; /* UDP */
 375     pkt->ip_hdr.chks = 0; /* Will be calculated later*/
 376     pkt->ip_hdr.sadr = ans->pkt.from;
 377     pkt->ip_hdr.dadr = ans->pkt.to;
 378
 379     pkt->ip_hdr.chks = calculate_ip_checksum((uint16_t*)&pkt->ip_hdr, 5*4);
 380
 381     /* set the udp-header */
 382     pkt->udp_dns.udp_hdr.spt = htons(53);
 383     pkt->udp_dns.udp_hdr.dpt = ans->pkt.dst_port;
 384     pkt->udp_dns.udp_hdr.len = htons(net_len - sizeof(struct ip_hdr));
 385     pkt->udp_dns.udp_hdr.crc = 0; /* Optional for IPv4 */
 386
 387     memcpy(&pkt->udp_dns.data, ans->pkt.data, data_len);
 388
 389     GNUNET_CONTAINER_DLL_remove (answer_proc_head, answer_proc_tail, ans);
 390     GNUNET_free(ans);
 391
 392     /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, pkt, pkt_len);
 393
 394     /* if more packets are available, reschedule */
 395     if (answer_proc_head != NULL)
 396       GNUNET_SCHEDULER_add_write_file (GNUNET_TIME_UNIT_FOREVER_REL,
 397                                        fh_to_helper,
 398                                        &helper_write,
 399                                        NULL);
 400 }
 401
 402 /**
 403  * @return the hash of the IP-Address if a mapping exists, NULL otherwise
 404  */
 405 static GNUNET_HashCode*
 406 address_mapping_exists(unsigned char addr[]) {
 407     GNUNET_HashCode* key = GNUNET_malloc(sizeof(GNUNET_HashCode));
 408     unsigned char* k = (unsigned char*)key;
 409     memset(key, 0, sizeof(GNUNET_HashCode));
 410     unsigned int i;
 411     for (i = 0; i < 16; i++)
 412         k[15-i] = addr[i];
 413
 414     if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains(hashmap, key))
 415       return key;
 416     else
 417       {
 418         GNUNET_free(key);
 419         return NULL;
 420       }
 421 }
 422
 423 static void
 424 send_icmp_response(void* cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 425     struct ip6_icmp* request = cls;
 426
 427     struct ip6_icmp* response = alloca(ntohs(request->shdr.size));
 428     memset(response, 0, ntohs(request->shdr.size));
 429
 430     response->shdr.size = request->shdr.size;
 431     response->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 432
 433     response->tun.flags = 0;
 434     response->tun.type = htons(0x86dd);
 435
 436     response->ip6_hdr.hoplmt = 255;
 437     response->ip6_hdr.paylgth = request->ip6_hdr.paylgth;
 438     response->ip6_hdr.nxthdr = 0x3a;
 439     response->ip6_hdr.version = 6;
 440     memcpy(&response->ip6_hdr.sadr, &request->ip6_hdr.dadr, 16);
 441     memcpy(&response->ip6_hdr.dadr, &request->ip6_hdr.sadr, 16);
 442
 443     response->icmp_hdr.code = 0;
 444     response->icmp_hdr.type = 0x81;
 445
 446     /* Magic, more Magic! */
 447     response->icmp_hdr.chks = request->icmp_hdr.chks - 0x1;
 448
 449     /* Copy the rest of the packet */
 450     memcpy(response+1, request+1, ntohs(request->shdr.size) - sizeof(struct ip6_icmp));
 451
 452     /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, response, ntohs(response->shdr.size));
 453
 454     GNUNET_free(request);
 455 }
 456
 457 /**
 458  * cls is the pointer to a GNUNET_MessageHeader that is
 459  * followed by the service-descriptor and the udp-packet that should be sent;
 460  */
 461 static size_t
 462 handle_udp (void *cls, size_t size, void *buf)
 463 {
 464   struct GNUNET_PeerIdentity *peer = cls;
 465   struct GNUNET_MessageHeader *hdr =
 466     (struct GNUNET_MessageHeader *) (peer + 1);
 467   GNUNET_HashCode *hc = (GNUNET_HashCode *) (hdr + 1);
 468   struct udp_pkt *udp = (struct udp_pkt *) (hc + 1);
 469   hdr->size = htons (sizeof (struct GNUNET_MessageHeader) +
 470                      sizeof (GNUNET_HashCode) + ntohs (udp->len));
 471   hdr->type = ntohs (GNUNET_MESSAGE_TYPE_SERVICE_UDP);
 472   GNUNET_assert (size >= ntohs (hdr->size));
 473   memcpy (buf, hdr, ntohs (hdr->size));
 474   size = ntohs(hdr->size);
 475   GNUNET_free (cls);
 476   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sent!\n");
 477   return size;
 478 }
 479
 480 static unsigned int
 481 port_in_ports (uint64_t ports, uint16_t port)
 482 {
 483   uint16_t *ps = (uint16_t *) & ports;
 484   return ps[0] == port || ps[1] == port || ps[2] == port || ps[3] == port;
 485 }
 486
 487 void
 488 send_udp (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 489 {
 490   struct GNUNET_PeerIdentity *peer = cls;
 491   struct GNUNET_MessageHeader *hdr =
 492     (struct GNUNET_MessageHeader *) (peer + 1);
 493   GNUNET_HashCode *hc = (GNUNET_HashCode *) (hdr + 1);
 494   struct udp_pkt *udp = (struct udp_pkt *) (hc + 1);
 495   GNUNET_CORE_notify_transmit_ready (core_handle,
 496                                      42,
 497                                      GNUNET_TIME_UNIT_FOREVER_REL,
 498                                      peer,
 499                                      htons (sizeof
 500                                             (struct GNUNET_MessageHeader) +
 501                                             sizeof (GNUNET_HashCode) +
 502                                             ntohs (udp->len)), handle_udp,
 503                                      cls);
 504 }
 505
 506 /**
 507  * Receive packets from the helper-process
 508  */
 509 static void
 510 message_token(void *cls,
 511               void *client,
 512               const struct GNUNET_MessageHeader *message) {
 513     GNUNET_assert(ntohs(message->type) == GNUNET_MESSAGE_TYPE_VPN_HELPER);
 514
 515     struct tun_pkt *pkt_tun = (struct tun_pkt*) message;
 516
 517     /* ethertype is ipv6 */
 518     if (ntohs(pkt_tun->tun.type) == 0x86dd)
 519       {
 520         struct ip6_pkt *pkt6 = (struct ip6_pkt*) message;
 521         GNUNET_assert(pkt6->ip6_hdr.version == 6);
 522         struct ip6_tcp *pkt6_tcp;
 523         struct ip6_udp *pkt6_udp;
 524         struct ip6_icmp *pkt6_icmp;
 525         GNUNET_HashCode* key;
 526
 527         pkt_printf(pkt6);
 528         switch(pkt6->ip6_hdr.nxthdr)
 529           {
 530           case 0x06:
 531             pkt6_tcp = (struct ip6_tcp*)pkt6;
 532             pkt_printf_ip6tcp(pkt6_tcp);
 533             break;
 534           case 0x11:
 535             pkt6_udp = (struct ip6_udp*)pkt6;
 536             if ((key = address_mapping_exists(pkt6->ip6_hdr.dadr)) != NULL)
 537               {
 538                 struct map_entry* me = GNUNET_CONTAINER_multihashmap_get(hashmap, key);
 539                 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Mapping exists; type: %d; UDP is %d; port: %x/%x!\n", me->desc.service_type, htonl(GNUNET_DNS_SERVICE_TYPE_UDP), pkt6_udp->udp_hdr.dpt, me->desc.ports);
 540                 GNUNET_free(key);
 541                 if (me->desc.service_type & htonl(GNUNET_DNS_SERVICE_TYPE_UDP) &&
 542                     port_in_ports(me->desc.ports, pkt6_udp->udp_hdr.dpt))
 543                   {
 544                     size_t size = sizeof(struct GNUNET_PeerIdentity) + sizeof(struct GNUNET_MessageHeader) + sizeof(GNUNET_HashCode) + ntohs(pkt6_udp->udp_hdr.len);
 545                     struct GNUNET_PeerIdentity *cls = GNUNET_malloc(size);
 546                     struct GNUNET_MessageHeader *hdr = (struct GNUNET_MessageHeader*)(cls+1);
 547                     GNUNET_HashCode* hc = (GNUNET_HashCode*)(hdr + 1);
 548                     memcpy(cls, &me->desc.peer, sizeof(struct GNUNET_PeerIdentity));
 549                     memcpy(hc, &me->desc.service_descriptor, sizeof(GNUNET_HashCode));
 550                     memcpy(hc+1, &pkt6_udp->udp_hdr, ntohs(pkt6_udp->udp_hdr.len));
 551                     GNUNET_CORE_peer_request_connect(core_handle,
 552                                         GNUNET_TIME_UNIT_FOREVER_REL,
 553                                         (struct GNUNET_PeerIdentity*)&me->desc.peer,
 554                                         send_udp,
 555                                         cls);
 556                     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Queued to send to peer %x\n", *((unsigned int*)&me->desc.peer));
 557                   }
 558               }
 559             break;
 560           case 0x3a:
 561             /* ICMPv6 */
 562             pkt6_icmp = (struct ip6_icmp*)pkt6;
 563             /* If this packet is an icmp-echo-request and a mapping exists, answer */
 564             if (pkt6_icmp->icmp_hdr.type == 0x80 && (key = address_mapping_exists(pkt6->ip6_hdr.dadr)) != NULL)
 565               {
 566                 GNUNET_free(key);
 567                 pkt6_icmp = GNUNET_malloc(ntohs(pkt6->shdr.size));
 568                 memcpy(pkt6_icmp, pkt6, ntohs(pkt6->shdr.size));
 569                 GNUNET_SCHEDULER_add_now(&send_icmp_response, pkt6_icmp);
 570               }
 571             break;
 572           }
 573       }
 574     /* ethertype is ipv4 */
 575     else if (ntohs(pkt_tun->tun.type) == 0x0800)
 576       {
 577         struct ip_pkt *pkt = (struct ip_pkt*) message;
 578         struct ip_udp *udp = (struct ip_udp*) message;
 579         GNUNET_assert(pkt->ip_hdr.version == 4);
 580
 581         /* Send dns-packets to the service-dns */
 582         if (pkt->ip_hdr.proto == 0x11 && ntohs(udp->udp_hdr.dpt) == 53 )
 583           {
 584             /* 9 = 8 for the udp-header + 1 for the unsigned char data[1]; */
 585             size_t len = sizeof(struct query_packet) + ntohs(udp->udp_hdr.len) - 9;
 586
 587             struct query_packet_list* query = GNUNET_malloc(len + 2*sizeof(struct query_packet_list*));
 588             query->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS);
 589             query->pkt.hdr.size = htons(len);
 590             query->pkt.orig_to = pkt->ip_hdr.dadr;
 591             query->pkt.orig_from = pkt->ip_hdr.sadr;
 592             query->pkt.src_port = udp->udp_hdr.spt;
 593             memcpy(query->pkt.data, udp->data, ntohs(udp->udp_hdr.len) - 8);
 594
 595             GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, query);
 596
 597             if (dns_connection != NULL)
 598               GNUNET_CLIENT_notify_transmit_ready(dns_connection,
 599                                                   len,
 600                                                   GNUNET_TIME_UNIT_FOREVER_REL,
 601                                                   GNUNET_YES,
 602                                                   &send_query,
 603                                                   NULL);
 604           }
 605       }
 606 }
 607
 608 /**
 609  * Connect to the service-dns
 610  */
 611 static void
 612 connect_to_service_dns (void *cls,
 613                         const struct GNUNET_SCHEDULER_TaskContext *tc) {
 614     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 615       return;
 616     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n");
 617     GNUNET_assert (dns_connection == NULL);
 618     dns_connection = GNUNET_CLIENT_connect ("dns", cfg);
 619     GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
 620
 621     /* If a packet is already in the list, schedule to send it */
 622     if (head != NULL)
 623       GNUNET_CLIENT_notify_transmit_ready(dns_connection,
 624                                           ntohs(head->pkt.hdr.size),
 625                                           GNUNET_TIME_UNIT_FOREVER_REL,
 626                                           GNUNET_YES,
 627                                           &send_query,
 628                                           NULL);
 629     else if (restart_hijack == 1)
 630       {
 631         GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 632       }
 633 }
 634
 635 /**
 636  * Create a new Address from an answer-packet
 637  * {{{
 638  */
 639 void
 640 new_ip6addr(char* buf, const GNUNET_HashCode *peer, const GNUNET_HashCode *service_desc) {
 641         memcpy(buf+14, (int[]){htons(0x3412)}, 2);
 642         memcpy(buf+8, service_desc, 6);
 643         memcpy(buf, peer, 8);
 644 }
 645 /*}}}*/
 646
 647 /**
 648  * This gets scheduled with cls pointing to an answer_packet and does everything
 649  * needed in order to send it to the helper.
 650  *
 651  * At the moment this means "inventing" and IPv6-Address for .gnunet-services and
 652  * doing nothing for "real" services.
 653  */
 654 static void
 655 process_answer(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
 656     struct answer_packet* pkt = cls;
 657     struct answer_packet_list* list;
 658
 659     /* This answer is about a .gnunet-service
 660      *
 661      * It contains an almost complete DNS-Response, we have to fill in the ip
 662      * at the offset pkt->addroffset
 663      */
 664     //FIXME htons?
 665     if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_SERVICE)
 666       {
 667         pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 668
 669         GNUNET_HashCode key;
 670         memset(&key, 0, sizeof(GNUNET_HashCode));
 671         new_ip6addr((char*)&key, &pkt->service_descr.peer, &pkt->service_descr.service_descriptor);
 672
 673         uint16_t namelen = strlen((char*)pkt->data+12)+1;
 674
 675         struct map_entry* value = GNUNET_malloc(sizeof(struct GNUNET_vpn_service_descriptor) + 2 + namelen);
 676
 677         value->namelen = namelen;
 678         memcpy(value->name, pkt->data+12, namelen);
 679
 680         memcpy(&value->desc, &pkt->service_descr, sizeof(struct GNUNET_vpn_service_descriptor));
 681
 682         if (GNUNET_OK != GNUNET_CONTAINER_multihashmap_put(hashmap,
 683                                                            &key,
 684                                                            value,
 685                                                            GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY))
 686           {
 687             GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not store to hashmap\n");
 688           }
 689
 690         /*
 691          * Copy the newly generated backward ip-address to the packet
 692          */
 693         char* c = ((char*)pkt)+ntohs(pkt->addroffset);
 694         char* k = (char*)&key;
 695         unsigned int i;
 696         for (i = 0; i < 16; i++)
 697             c[15-i] = k[i];
 698
 699         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 700
 701         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 702
 703       }
 704     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_REV)
 705       {
 706         GNUNET_HashCode key;
 707         memset(&key, 0, sizeof key);
 708         unsigned char* k = (unsigned char*)&key;
 709         unsigned char* s = pkt->data+12;
 710         int i = 0;
 711         /* Whoever designed the reverse IPv6-lookup is batshit insane */
 712         for (i = 0; i < 16; i++)
 713           {
 714             unsigned char c1 = s[(4*i)+1];
 715             unsigned char c2 = s[(4*i)+3];
 716             if (c1 <= '9')
 717               k[i] = c1 - '0';
 718             else
 719               k[i] = c1 - 87; /* 87 is the difference between 'a' and 10 */
 720             if (c2 <= '9')
 721               k[i] += 16*(c2 - '0');
 722             else
 723               k[i] += 16*(c2 - 87);
 724           }
 725
 726         struct map_entry* map_entry = GNUNET_CONTAINER_multihashmap_get(hashmap, &key);
 727         unsigned short offset = ntohs(pkt->addroffset);
 728
 729         if (map_entry == NULL)
 730           {
 731             GNUNET_free(pkt);
 732             return;
 733           }
 734
 735         unsigned short namelen = htons(map_entry->namelen);
 736         char* name = map_entry->name;
 737
 738         list = GNUNET_malloc(2*sizeof(struct answer_packet_list*) + offset + 2 + ntohs(namelen));
 739
 740         struct answer_packet* rpkt = &list->pkt;
 741
 742         memcpy(rpkt, pkt, offset);
 743
 744         rpkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 745         rpkt->hdr.size = ntohs(offset + 2 + ntohs(namelen));
 746
 747         memcpy(((char*)rpkt)+offset, &namelen, 2);
 748         memcpy(((char*)rpkt)+offset+2, name, ntohs(namelen));
 749
 750       }
 751     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_IP)
 752       {
 753         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 754         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 755       }
 756     else
 757       {
 758         GNUNET_break(0);
 759         GNUNET_free(pkt);
 760         return;
 761       }
 762
 763     GNUNET_free(pkt);
 764
 765     GNUNET_CONTAINER_DLL_insert_after(answer_proc_head, answer_proc_tail, answer_proc_tail, list);
 766
 767     GNUNET_SCHEDULER_add_write_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_to_helper, &helper_write, NULL);
 768
 769     return;
 770 }
 771
 772 /**
 773  * This receives packets from the service-dns and schedules process_answer to
 774  * handle it
 775  */
 776 static void
 777 dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg) {
 778     /* the service disconnected, reconnect after short wait */
 779     if (msg == NULL)
 780       {
 781         GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
 782         dns_connection = NULL;
 783         GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
 784                                       &connect_to_service_dns,
 785                                       NULL);
 786         return;
 787       }
 788
 789     /* the service did something strange, reconnect immediately */
 790     if (msg->type != htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS))
 791       {
 792         GNUNET_break (0);
 793         GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
 794         dns_connection = NULL;
 795         GNUNET_SCHEDULER_add_now (&connect_to_service_dns,
 796                                   NULL);
 797         return;
 798       }
 799     void *pkt = GNUNET_malloc(ntohs(msg->size));
 800
 801     memcpy(pkt, msg, ntohs(msg->size));
 802
 803     GNUNET_SCHEDULER_add_now(process_answer, pkt);
 804     GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
 805 }
 806
 807 struct udp_state
 808 {
 809   struct GNUNET_PeerIdentity peer;
 810   GNUNET_HashCode desc;
 811   short spt;
 812   short dpt;
 813 };
 814
 815 struct send_cls
 816 {
 817   struct GNUNET_NETWORK_Handle *sock;
 818   struct udp_state state;
 819 };
 820
 821 static size_t
 822 send_udp_service (void *cls, size_t size, void *buf)
 823 {
 824   struct GNUNET_MessageHeader *hdr = cls;
 825   GNUNET_assert(size >= ntohs(hdr->size));
 826
 827   memcpy(buf, cls, ntohs(hdr->size));
 828   size_t ret = ntohs(hdr->size);
 829   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Sending %d bytes back!\n", ntohs(hdr->size));
 830   GNUNET_free(cls);
 831   return ret;
 832 }
 833
 834 void
 835 receive_from_network (void *cls,
 836                       const struct GNUNET_SCHEDULER_TaskContext *tc)
 837 {
 838   if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 839     {
 840       GNUNET_free(cls);
 841       return;
 842     }
 843   struct send_cls *data = cls;
 844
 845   char buf[1400];
 846
 847   ssize_t len = GNUNET_NETWORK_socket_recv (data->sock, buf, 1400);
 848
 849   if (len < 0) {
 850     GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Problem reading from socket: %m\n");
 851     goto out;
 852   }
 853
 854   size_t len_udp = len + sizeof (struct udp_pkt);
 855   size_t len_pkt = len_udp + sizeof (struct GNUNET_MessageHeader) + sizeof(GNUNET_HashCode);
 856   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Sending data back: data: %d; udp: %d, pkt:%d\n", len, len_udp, len_pkt);
 857
 858   struct GNUNET_MessageHeader *hdr = GNUNET_malloc (len_pkt);
 859   GNUNET_HashCode *desc = (GNUNET_HashCode *) (hdr + 1);
 860   struct udp_pkt *pkt = (struct udp_pkt *) (desc + 1);
 861
 862   hdr->size = htons (len_pkt);
 863   hdr->type = htons (GNUNET_MESSAGE_TYPE_SERVICE_UDP_BACK);
 864
 865   pkt->dpt = htons(data->state.spt);
 866   pkt->spt = htons(data->state.dpt);
 867   pkt->len = htons (len_udp);
 868   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "UDP from %d to %d\n", ntohs(pkt->spt), ntohs(pkt->dpt));
 869   /* The chksm can only be computed knowing the ip-addresses */
 870
 871   memcpy (desc, &data->state.desc, sizeof (GNUNET_HashCode));
 872   memcpy (pkt + 1, buf, len);
 873
 874   GNUNET_CORE_notify_transmit_ready (core_handle, 42,
 875                                      GNUNET_TIME_UNIT_FOREVER_REL,
 876                                      &data->state.peer, len_pkt,
 877                                      send_udp_service, hdr);
 878
 879 out:
 880   GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, data->sock,
 881                                  receive_from_network, cls);
 882 }
 883
 884 void
 885 send_to_network (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 886 {
 887   if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 888     return;
 889   struct send_cls *data = cls;
 890   struct udp_pkt *pkt = (struct udp_pkt *) (data + 1);
 891
 892   struct sockaddr_in a4;
 893   memset(&a4, 0, sizeof(struct sockaddr_in));
 894   a4.sin_family = AF_INET;
 895   a4.sin_port = htons(data->state.dpt);
 896   memcpy(&a4.sin_addr.s_addr, (char[]){127, 0, 0, 1}, 4);
 897
 898   GNUNET_NETWORK_socket_sendto (data->sock, pkt + 1,
 899                                 ntohs (pkt->len) - sizeof (struct udp_pkt),
 900                                 (struct sockaddr*)&a4, sizeof a4);
 901
 902   GNUNET_free(cls);
 903
 904 }
 905
 906 static int
 907 receive_udp_back (void *cls, const struct GNUNET_PeerIdentity *other,
 908              const struct GNUNET_MessageHeader *message,
 909              const struct GNUNET_TRANSPORT_ATS_Information *atsi)
 910 {
 911   GNUNET_HashCode *desc = (GNUNET_HashCode *) (message + 1);
 912   struct udp_pkt *pkt = (struct udp_pkt *) (desc + 1);
 913   char addr[16];
 914   new_ip6addr(addr, &other->hashPubKey, desc);
 915
 916   size_t size = sizeof(struct ip6_udp) + ntohs(pkt->len) - 1 - sizeof(struct udp_pkt);
 917
 918   struct ip6_udp* pkt6 = alloca(size);
 919
 920   pkt6->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 921   pkt6->shdr.size = htons(size);
 922
 923   pkt6->tun.flags = 0;
 924   pkt6->tun.type = htons(0x86dd);
 925
 926   pkt6->ip6_hdr.version = 6;
 927   pkt6->ip6_hdr.tclass_h = 0;
 928   pkt6->ip6_hdr.tclass_l = 0;
 929   pkt6->ip6_hdr.flowlbl = 0;
 930   pkt6->ip6_hdr.paylgth = pkt->len;
 931   pkt6->ip6_hdr.nxthdr = 0x11;
 932   pkt6->ip6_hdr.hoplmt = 0xff;
 933
 934   unsigned int i;
 935   for (i = 0; i < 16; i++)
 936     pkt6->ip6_hdr.sadr[15-i] = addr[i];
 937
 938   memcpy(pkt6->ip6_hdr.dadr, (unsigned char[]){0x12, 0x34, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, 16);
 939
 940   memcpy(&pkt6->udp_hdr, pkt, ntohs(pkt->len));
 941
 942   pkt6->udp_hdr.crc = 0;
 943   uint32_t sum = 0;
 944   sum = calculate_checksum_update(sum, (uint16_t*)&pkt6->ip6_hdr.sadr, 16);
 945   sum = calculate_checksum_update(sum, (uint16_t*)&pkt6->ip6_hdr.dadr, 16);
 946   uint32_t tmp = (pkt6->udp_hdr.len & 0xffff);
 947   sum = calculate_checksum_update(sum, (uint16_t*)&tmp, 4);
 948   tmp = htons(((pkt6->ip6_hdr.nxthdr & 0x00ff)));
 949   sum = calculate_checksum_update(sum, (uint16_t*)&tmp, 4);
 950
 951   sum = calculate_checksum_update(sum, (uint16_t*)&pkt6->udp_hdr, ntohs(pkt->len));
 952   pkt6->udp_hdr.crc = calculate_checksum_end(sum);
 953
 954
 955   /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, pkt6, size);
 956
 957   return GNUNET_OK;
 958 }
 959
 960 static int
 961 receive_udp_service (void *cls, const struct GNUNET_PeerIdentity *other,
 962                      const struct GNUNET_MessageHeader *message,
 963                      const struct GNUNET_TRANSPORT_ATS_Information *atsi)
 964 {
 965   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received UDP-Packet from peer %s\n",
 966               GNUNET_i2s (other));
 967   GNUNET_HashCode *desc = (GNUNET_HashCode *) (message + 1);
 968   struct udp_pkt *pkt = (struct udp_pkt *) (desc + 1);
 969
 970   /* FIXME -> check acl etc */
 971   GNUNET_assert (ntohs (pkt->len) ==
 972                  ntohs (message->size) -
 973                  sizeof (struct GNUNET_MessageHeader) -
 974                  sizeof (GNUNET_HashCode));
 975
 976   size_t state_size = sizeof (struct udp_state);
 977   size_t cls_size = sizeof (struct send_cls) + ntohs (pkt->len);
 978   struct send_cls *send = GNUNET_malloc (cls_size);
 979   struct udp_state *state = &send->state;
 980   unsigned int new = GNUNET_NO;
 981
 982   memcpy (&state->peer, other, sizeof (struct GNUNET_PeerIdentity));
 983   memcpy (&state->desc, desc, sizeof (GNUNET_HashCode));
 984   state->spt = ntohs (pkt->spt);
 985   state->dpt = ntohs (pkt->dpt);
 986
 987   memcpy (send + 1, pkt, ntohs (pkt->len));
 988
 989   GNUNET_HashCode hash;
 990   GNUNET_CRYPTO_hash (state, state_size, &hash);
 991
 992   struct GNUNET_NETWORK_Handle *sock =
 993     GNUNET_CONTAINER_multihashmap_get (udp_connections, &hash);
 994
 995   if (sock == NULL)
 996     {
 997       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Creating new Socket!\n");
 998       sock = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
 999       new = GNUNET_YES;
1000     }
1001
1002   send->sock = sock;
1003
1004   GNUNET_CONTAINER_multihashmap_put (udp_connections, &hash, sock,
1005                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
1006
1007
1008   if (new)
1009     {
1010       struct send_cls *recv = GNUNET_malloc (sizeof (struct send_cls));
1011       memcpy (recv, send, sizeof (struct send_cls));
1012       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, sock,
1013                                      receive_from_network, recv);
1014     }
1015
1016   GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL, sock,
1017                                   send_to_network, send);
1018
1019   return GNUNET_OK;
1020 }
1021
1022 /**
1023  * Main function that will be run by the scheduler.
1024  *
1025  * @param cls closure
1026  * @param args remaining command-line arguments
1027  * @param cfgfile name of the configuration file used (for saving, can be NULL!)
1028  * @param cfg configuration
1029  */
1030 static void
1031 run (void *cls,
1032      char *const *args,
1033      const char *cfgfile,
1034      const struct GNUNET_CONFIGURATION_Handle *cfg_) {
1035     const static struct GNUNET_CORE_MessageHandler handlers[] = {
1036           {receive_udp_service, GNUNET_MESSAGE_TYPE_SERVICE_UDP, 0},
1037           {receive_udp_back, GNUNET_MESSAGE_TYPE_SERVICE_UDP_BACK, 0},
1038           {NULL, 0, 0}
1039     };
1040     core_handle = GNUNET_CORE_connect(cfg_,
1041                                       42,
1042                                       NULL,
1043                                       NULL,
1044                                       NULL,
1045                                       NULL,
1046                                       NULL,
1047                                       NULL,
1048                                       0,
1049                                       NULL,
1050                                       0,
1051                                       handlers);
1052     mst = GNUNET_SERVER_mst_create(&message_token, NULL);
1053     cfg = cfg_;
1054     restart_hijack = 0;
1055     hashmap = GNUNET_CONTAINER_multihashmap_create(65536);
1056     udp_connections = GNUNET_CONTAINER_multihashmap_create(65536);
1057     GNUNET_SCHEDULER_add_now (connect_to_service_dns, NULL);
1058     GNUNET_SCHEDULER_add_now (start_helper_and_schedule, NULL);
1059     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_FOREVER_REL, &cleanup, cls);
1060 }
1061
1062 /**
1063  * The main function to obtain template from gnunetd.
1064  *
1065  * @param argc number of arguments from the command line
1066  * @param argv command line arguments
1067  * @return 0 ok, 1 on error
1068  */
1069 int
1070 main (int argc, char *const *argv) {
1071     static const struct GNUNET_GETOPT_CommandLineOption options[] = {
1072         GNUNET_GETOPT_OPTION_END
1073     };
1074
1075     return (GNUNET_OK ==
1076             GNUNET_PROGRAM_run (argc,
1077                                 argv,
1078                                 "gnunet-daemon-vpn",
1079                                 gettext_noop ("help text"),
1080                                 options, &run, NULL)) ? ret : 1;
1081 }
1082
1083 /* end of gnunet-daemon-vpn.c */