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  * The handle to core
 125  */
 126 static struct GNUNET_CORE_Handle *core_handle;
 127
 128 struct map_entry {
 129     struct GNUNET_vpn_service_descriptor desc;
 130     uint16_t namelen;
 131     /**
 132      * In DNS-Format!
 133      */
 134     char name[1];
 135 };
 136
 137 static void helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx);
 138 static void dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg);
 139
 140 /**
 141  * Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages
 142  * to the service-dns
 143  * {{{
 144  */
 145 static size_t
 146 send_query(void* cls, size_t size, void* buf) {
 147     size_t len;
 148     /*
 149      * Send the rehijack-message
 150      */
 151     if (restart_hijack == 1)
 152       {
 153         restart_hijack = 0;
 154         /*
 155          * The message is just a header
 156          */
 157         GNUNET_assert(sizeof(struct GNUNET_MessageHeader) <= size);
 158         struct GNUNET_MessageHeader* hdr = buf;
 159         len = sizeof(struct GNUNET_MessageHeader);
 160         hdr->size = htons(len);
 161         hdr->type = htons(GNUNET_MESSAGE_TYPE_REHIJACK);
 162       }
 163     else
 164       {
 165         struct query_packet_list* query = head;
 166         len = ntohs(query->pkt.hdr.size);
 167
 168         GNUNET_assert(len <= size);
 169
 170         memcpy(buf, &query->pkt.hdr, len);
 171
 172         GNUNET_CONTAINER_DLL_remove (head, tail, query);
 173
 174         GNUNET_free(query);
 175       }
 176
 177     /*
 178      * Check whether more data is to be sent
 179      */
 180     if (head != NULL)
 181       {
 182         GNUNET_CLIENT_notify_transmit_ready(dns_connection, ntohs(head->pkt.hdr.size), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 183       }
 184     else if (restart_hijack == 1)
 185       {
 186         GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 187       }
 188
 189     return len;
 190 }
 191 /* }}} */
 192
 193 /**
 194  * Function scheduled as very last function, cleans up after us
 195  *{{{
 196  */
 197 static void
 198 cleanup(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 199     GNUNET_assert (0 != (tskctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN));
 200
 201     /* stop the helper */
 202     if (helper_proc != NULL)
 203       {
 204         GNUNET_OS_process_kill (helper_proc, SIGTERM);
 205         GNUNET_OS_process_wait (helper_proc);
 206         GNUNET_OS_process_close (helper_proc);
 207         helper_proc = NULL;
 208       }
 209
 210     /* close the connection to the service-dns */
 211     if (dns_connection != NULL)
 212       {
 213         GNUNET_CLIENT_disconnect (dns_connection, GNUNET_NO);
 214         dns_connection = NULL;
 215       }
 216
 217     if (core_handle != NULL)
 218       {
 219         GNUNET_CORE_disconnect(core_handle);
 220         core_handle = NULL;
 221       }
 222 }
 223 /*}}}*/
 224
 225 /**
 226  * Start the helper-process
 227  * {{{
 228  */
 229 static void
 230 start_helper_and_schedule(void *cls,
 231                           const struct GNUNET_SCHEDULER_TaskContext *tc) {
 232     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 233       return;
 234
 235     helper_in = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_YES, GNUNET_NO);
 236     helper_out = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_NO, GNUNET_YES);
 237
 238     if (helper_in == NULL || helper_out == NULL) return;
 239
 240     helper_proc = GNUNET_OS_start_process(helper_in, helper_out, "gnunet-helper-vpn", "gnunet-helper-vpn", NULL);
 241
 242     fh_from_helper = GNUNET_DISK_pipe_handle (helper_out, GNUNET_DISK_PIPE_END_READ);
 243     fh_to_helper = GNUNET_DISK_pipe_handle (helper_in, GNUNET_DISK_PIPE_END_WRITE);
 244
 245     GNUNET_DISK_pipe_close_end(helper_out, GNUNET_DISK_PIPE_END_WRITE);
 246     GNUNET_DISK_pipe_close_end(helper_in, GNUNET_DISK_PIPE_END_READ);
 247
 248     /* Tell the dns-service to rehijack the dns-port
 249      * The routing-table gets flushed if an interface disappears.
 250      */
 251     restart_hijack = 1;
 252     GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 253
 254     GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 255 }
 256 /*}}}*/
 257
 258 /**
 259  * Restart the helper-process
 260  * {{{
 261  */
 262 static void
 263 restart_helper(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 264     // Kill the helper
 265     GNUNET_OS_process_kill (helper_proc, SIGKILL);
 266     GNUNET_OS_process_wait (helper_proc);
 267     GNUNET_OS_process_close (helper_proc);
 268     helper_proc = NULL;
 269
 270     GNUNET_DISK_pipe_close(helper_in);
 271     GNUNET_DISK_pipe_close(helper_out);
 272
 273     /* Restart the helper */
 274     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, start_helper_and_schedule, NULL);
 275 }
 276 /*}}}*/
 277
 278 /**
 279  * Read from the helper-process
 280  * {{{
 281  */
 282 static void
 283 helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 284     /* no message can be bigger then 64k */
 285     char buf[65535];
 286
 287     if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 288       return;
 289
 290     int t = GNUNET_DISK_file_read(fh_from_helper, &buf, 65535);
 291
 292     /* On read-error, restart the helper */
 293     if (t<=0) {
 294         GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Read error for header from vpn-helper: %m\n");
 295         GNUNET_SCHEDULER_add_now(restart_helper, cls);
 296         return;
 297     }
 298
 299     /* FIXME */ GNUNET_SERVER_mst_receive(mst, NULL, buf, t, 0, 0);
 300
 301     GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 302 }
 303 /*}}}*/
 304
 305 /**
 306  * Calculate the checksum of an IPv4-Header
 307  */
 308 static uint16_t
 309 calculate_ip_checksum(uint16_t* hdr, short len) {
 310     uint32_t sum = 0;
 311     for(; len >= 2; len -= 2)
 312       sum += *(hdr++);
 313     if (len == 1)
 314       sum += *((unsigned char*)hdr);
 315
 316     sum = (sum >> 16) + (sum & 0xFFFF);
 317
 318     return ~sum;
 319 }
 320
 321 /**
 322  * Send an dns-answer-packet to the helper
 323  */
 324 static void
 325 helper_write(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 326     if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 327       return;
 328
 329     struct answer_packet_list* ans = answer_proc_head;
 330     size_t len = ntohs(ans->pkt.hdr.size);
 331
 332     GNUNET_assert(ans->pkt.subtype == GNUNET_DNS_ANSWER_TYPE_IP);
 333
 334     GNUNET_assert (20 == sizeof (struct ip_hdr));
 335     GNUNET_assert (8 == sizeof (struct udp_pkt));
 336     size_t data_len = len - sizeof(struct answer_packet) + 1;
 337     size_t net_len = sizeof(struct ip_hdr) + sizeof(struct udp_dns) + data_len;
 338     size_t pkt_len = sizeof(struct GNUNET_MessageHeader) + sizeof(struct pkt_tun) + net_len;
 339
 340     struct ip_udp_dns* pkt = alloca(pkt_len);
 341     memset(pkt, 0, pkt_len);
 342
 343     /* set the gnunet-header */
 344     pkt->shdr.size = htons(pkt_len);
 345     pkt->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 346
 347     /* set the tun-header (no flags and ethertype of IPv4) */
 348     pkt->tun.flags = 0;
 349     pkt->tun.type = htons(0x0800);
 350
 351     /* set the ip-header */
 352     pkt->ip_hdr.version = 4;
 353     pkt->ip_hdr.hdr_lngth = 5;
 354     pkt->ip_hdr.diff_serv = 0;
 355     pkt->ip_hdr.tot_lngth = htons(net_len);
 356     pkt->ip_hdr.ident = 0;
 357     pkt->ip_hdr.flags = 0;
 358     pkt->ip_hdr.frag_off = 0;
 359     pkt->ip_hdr.ttl = 255;
 360     pkt->ip_hdr.proto = 0x11; /* UDP */
 361     pkt->ip_hdr.chks = 0; /* Will be calculated later*/
 362     pkt->ip_hdr.sadr = ans->pkt.from;
 363     pkt->ip_hdr.dadr = ans->pkt.to;
 364
 365     pkt->ip_hdr.chks = calculate_ip_checksum((uint16_t*)&pkt->ip_hdr, 5*4);
 366
 367     /* set the udp-header */
 368     pkt->udp_dns.udp_hdr.spt = htons(53);
 369     pkt->udp_dns.udp_hdr.dpt = ans->pkt.dst_port;
 370     pkt->udp_dns.udp_hdr.len = htons(net_len - sizeof(struct ip_hdr));
 371     pkt->udp_dns.udp_hdr.crc = 0; /* Optional for IPv4 */
 372
 373     memcpy(&pkt->udp_dns.data, ans->pkt.data, data_len);
 374
 375     GNUNET_CONTAINER_DLL_remove (answer_proc_head, answer_proc_tail, ans);
 376     GNUNET_free(ans);
 377
 378     /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, pkt, pkt_len);
 379
 380     /* if more packets are available, reschedule */
 381     if (answer_proc_head != NULL)
 382       GNUNET_SCHEDULER_add_write_file (GNUNET_TIME_UNIT_FOREVER_REL,
 383                                        fh_to_helper,
 384                                        &helper_write,
 385                                        NULL);
 386 }
 387
 388 /**
 389  * @return the hash of the IP-Address if a mapping exists, NULL otherwise
 390  */
 391 static GNUNET_HashCode*
 392 address_mapping_exists(unsigned char addr[]) {
 393     GNUNET_HashCode* key = GNUNET_malloc(sizeof(GNUNET_HashCode));
 394     unsigned char* k = (unsigned char*)key;
 395     memset(key, 0, sizeof(GNUNET_HashCode));
 396     unsigned int i;
 397     for (i = 0; i < 16; i++)
 398         k[15-i] = addr[i];
 399
 400     if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains(hashmap, key))
 401       return key;
 402     else
 403       {
 404         GNUNET_free(key);
 405         return NULL;
 406       }
 407 }
 408
 409 static void
 410 send_icmp_response(void* cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 411     struct ip6_icmp* request = cls;
 412
 413     struct ip6_icmp* response = alloca(ntohs(request->shdr.size));
 414     memset(response, 0, ntohs(request->shdr.size));
 415
 416     response->shdr.size = request->shdr.size;
 417     response->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 418
 419     response->tun.flags = 0;
 420     response->tun.type = htons(0x86dd);
 421
 422     response->ip6_hdr.hoplmt = 255;
 423     response->ip6_hdr.paylgth = request->ip6_hdr.paylgth;
 424     response->ip6_hdr.nxthdr = 0x3a;
 425     response->ip6_hdr.version = 6;
 426     memcpy(&response->ip6_hdr.sadr, &request->ip6_hdr.dadr, 16);
 427     memcpy(&response->ip6_hdr.dadr, &request->ip6_hdr.sadr, 16);
 428
 429     response->icmp_hdr.code = 0;
 430     response->icmp_hdr.type = 0x81;
 431
 432     /* Magic, more Magic! */
 433     response->icmp_hdr.chks = request->icmp_hdr.chks - 0x1;
 434
 435     /* Copy the rest of the packet */
 436     memcpy(response+1, request+1, ntohs(request->shdr.size) - sizeof(struct ip6_icmp));
 437
 438     /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, response, ntohs(response->shdr.size));
 439
 440     GNUNET_free(request);
 441 }
 442
 443 /**
 444  * cls is the pointer to a GNUNET_MessageHeader that is
 445  * followed by the service-descriptor and the udp-packet that should be sent;
 446  */
 447 static size_t
 448 handle_udp (void *cls, size_t size, void *buf)
 449 {
 450   struct GNUNET_PeerIdentity *peer = cls;
 451   struct GNUNET_MessageHeader *hdr =
 452     (struct GNUNET_MessageHeader *) (peer + 1);
 453   GNUNET_HashCode *hc = (GNUNET_HashCode *) (hdr + 1);
 454   struct udp_pkt *udp = (struct udp_pkt *) (hc + 1);
 455   hdr->size = htons (sizeof (struct GNUNET_MessageHeader) +
 456                      sizeof (GNUNET_HashCode) + ntohs (udp->len));
 457   hdr->type = ntohs (GNUNET_MESSAGE_TYPE_SERVICE_UDP);
 458   GNUNET_assert (size >= ntohs (hdr->size));
 459   memcpy (buf, hdr, ntohs (hdr->size));
 460   GNUNET_free (cls);
 461   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sent!\n");
 462   return ntohs (hdr->size);
 463 }
 464
 465 static unsigned int
 466 port_in_ports (uint64_t ports, uint16_t port)
 467 {
 468   uint16_t *ps = (uint16_t *) & ports;
 469   return ps[0] == port || ps[1] == port || ps[2] == port || ps[3] == port;
 470 }
 471
 472 void
 473 send_udp (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 474 {
 475   struct GNUNET_PeerIdentity *peer = cls;
 476   struct GNUNET_MessageHeader *hdr =
 477     (struct GNUNET_MessageHeader *) (peer + 1);
 478   GNUNET_HashCode *hc = (GNUNET_HashCode *) (hdr + 1);
 479   struct udp_pkt *udp = (struct udp_pkt *) (hc + 1);
 480   GNUNET_CORE_notify_transmit_ready (core_handle,
 481                                      42,
 482                                      GNUNET_TIME_UNIT_FOREVER_REL,
 483                                      peer,
 484                                      htons (sizeof
 485                                             (struct GNUNET_MessageHeader) +
 486                                             sizeof (GNUNET_HashCode) +
 487                                             ntohs (udp->len)), handle_udp,
 488                                      cls);
 489 }
 490
 491 /**
 492  * Receive packets from the helper-process
 493  */
 494 static void
 495 message_token(void *cls,
 496               void *client,
 497               const struct GNUNET_MessageHeader *message) {
 498     GNUNET_assert(ntohs(message->type) == GNUNET_MESSAGE_TYPE_VPN_HELPER);
 499
 500     struct tun_pkt *pkt_tun = (struct tun_pkt*) message;
 501
 502     /* ethertype is ipv6 */
 503     if (ntohs(pkt_tun->tun.type) == 0x86dd)
 504       {
 505         struct ip6_pkt *pkt6 = (struct ip6_pkt*) message;
 506         GNUNET_assert(pkt6->ip6_hdr.version == 6);
 507         struct ip6_tcp *pkt6_tcp;
 508         struct ip6_udp *pkt6_udp;
 509         struct ip6_icmp *pkt6_icmp;
 510         GNUNET_HashCode* key;
 511
 512         pkt_printf(pkt6);
 513         switch(pkt6->ip6_hdr.nxthdr)
 514           {
 515           case 0x06:
 516             pkt6_tcp = (struct ip6_tcp*)pkt6;
 517             pkt_printf_ip6tcp(pkt6_tcp);
 518             break;
 519           case 0x11:
 520             pkt6_udp = (struct ip6_udp*)pkt6;
 521             if ((key = address_mapping_exists(pkt6->ip6_hdr.dadr)) != NULL)
 522               {
 523                 struct map_entry* me = GNUNET_CONTAINER_multihashmap_get(hashmap, key);
 524                 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);
 525                 GNUNET_free(key);
 526                 if (me->desc.service_type & htonl(GNUNET_DNS_SERVICE_TYPE_UDP) &&
 527                     port_in_ports(me->desc.ports, pkt6_udp->udp_hdr.dpt))
 528                   {
 529                     size_t size = sizeof(struct GNUNET_PeerIdentity) + sizeof(struct GNUNET_MessageHeader) + sizeof(GNUNET_HashCode) + ntohs(pkt6_udp->udp_hdr.len);
 530                     struct GNUNET_PeerIdentity *cls = GNUNET_malloc(size);
 531                     struct GNUNET_MessageHeader *hdr = (struct GNUNET_MessageHeader*)(cls+1);
 532                     GNUNET_HashCode* hc = (GNUNET_HashCode*)(hdr + 1);
 533                     memcpy(cls, &me->desc.peer, sizeof(struct GNUNET_PeerIdentity));
 534                     memcpy(hc, &me->desc.service_descriptor, sizeof(GNUNET_HashCode));
 535                     memcpy(hc+1, &pkt6_udp->udp_hdr, ntohs(pkt6_udp->udp_hdr.len));
 536                     GNUNET_CORE_peer_request_connect(core_handle,
 537                                         GNUNET_TIME_UNIT_FOREVER_REL,
 538                                         (struct GNUNET_PeerIdentity*)&me->desc.peer,
 539                                         send_udp,
 540                                         cls);
 541                     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Queued to send to peer %x\n", *((unsigned int*)&me->desc.peer));
 542                   }
 543               }
 544             break;
 545           case 0x3a:
 546             /* ICMPv6 */
 547             pkt6_icmp = (struct ip6_icmp*)pkt6;
 548             /* If this packet is an icmp-echo-request and a mapping exists, answer */
 549             if (pkt6_icmp->icmp_hdr.type == 0x80 && (key = address_mapping_exists(pkt6->ip6_hdr.dadr)) != NULL)
 550               {
 551                 GNUNET_free(key);
 552                 pkt6_icmp = GNUNET_malloc(ntohs(pkt6->shdr.size));
 553                 memcpy(pkt6_icmp, pkt6, ntohs(pkt6->shdr.size));
 554                 GNUNET_SCHEDULER_add_now(&send_icmp_response, pkt6_icmp);
 555               }
 556             break;
 557           }
 558       }
 559     /* ethertype is ipv4 */
 560     else if (ntohs(pkt_tun->tun.type) == 0x0800)
 561       {
 562         struct ip_pkt *pkt = (struct ip_pkt*) message;
 563         struct ip_udp *udp = (struct ip_udp*) message;
 564         GNUNET_assert(pkt->ip_hdr.version == 4);
 565
 566         /* Send dns-packets to the service-dns */
 567         if (pkt->ip_hdr.proto == 0x11 && ntohs(udp->udp_hdr.dpt) == 53 )
 568           {
 569             /* 9 = 8 for the udp-header + 1 for the unsigned char data[1]; */
 570             size_t len = sizeof(struct query_packet) + ntohs(udp->udp_hdr.len) - 9;
 571
 572             struct query_packet_list* query = GNUNET_malloc(len + 2*sizeof(struct query_packet_list*));
 573             query->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS);
 574             query->pkt.hdr.size = htons(len);
 575             query->pkt.orig_to = pkt->ip_hdr.dadr;
 576             query->pkt.orig_from = pkt->ip_hdr.sadr;
 577             query->pkt.src_port = udp->udp_hdr.spt;
 578             memcpy(query->pkt.data, udp->data, ntohs(udp->udp_hdr.len) - 8);
 579
 580             GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, query);
 581
 582             if (dns_connection != NULL)
 583               GNUNET_CLIENT_notify_transmit_ready(dns_connection,
 584                                                   len,
 585                                                   GNUNET_TIME_UNIT_FOREVER_REL,
 586                                                   GNUNET_YES,
 587                                                   &send_query,
 588                                                   NULL);
 589           }
 590       }
 591 }
 592
 593 /**
 594  * Connect to the service-dns
 595  */
 596 static void
 597 connect_to_service_dns (void *cls,
 598                         const struct GNUNET_SCHEDULER_TaskContext *tc) {
 599     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 600       return;
 601     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n");
 602     GNUNET_assert (dns_connection == NULL);
 603     dns_connection = GNUNET_CLIENT_connect ("dns", cfg);
 604     GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
 605
 606     /* If a packet is already in the list, schedule to send it */
 607     if (head != NULL)
 608       GNUNET_CLIENT_notify_transmit_ready(dns_connection,
 609                                           ntohs(head->pkt.hdr.size),
 610                                           GNUNET_TIME_UNIT_FOREVER_REL,
 611                                           GNUNET_YES,
 612                                           &send_query,
 613                                           NULL);
 614     else if (restart_hijack == 1)
 615       {
 616         GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 617       }
 618 }
 619
 620 /**
 621  * Create a new Address from an answer-packet
 622  * {{{
 623  */
 624 void
 625 new_ip6addr(char* buf, struct answer_packet* pkt) {
 626         memcpy(buf+14, (int[]){htons(0x3412)}, 2);
 627         memcpy(buf+8, &pkt->service_descr.service_descriptor, 6);
 628         memcpy(buf, &pkt->service_descr.peer, 8);
 629 }
 630 /*}}}*/
 631
 632 /**
 633  * This gets scheduled with cls pointing to an answer_packet and does everything
 634  * needed in order to send it to the helper.
 635  *
 636  * At the moment this means "inventing" and IPv6-Address for .gnunet-services and
 637  * doing nothing for "real" services.
 638  */
 639 static void
 640 process_answer(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
 641     struct answer_packet* pkt = cls;
 642     struct answer_packet_list* list;
 643
 644     /* This answer is about a .gnunet-service
 645      *
 646      * It contains an almost complete DNS-Response, we have to fill in the ip
 647      * at the offset pkt->addroffset
 648      */
 649     //FIXME htons?
 650     if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_SERVICE)
 651       {
 652         pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 653
 654         GNUNET_HashCode key;
 655         memset(&key, 0, sizeof(GNUNET_HashCode));
 656         new_ip6addr((char*)&key, pkt);
 657
 658         uint16_t namelen = strlen((char*)pkt->data+12)+1;
 659
 660         struct map_entry* value = GNUNET_malloc(sizeof(struct GNUNET_vpn_service_descriptor) + 2 + namelen);
 661
 662         value->namelen = namelen;
 663         memcpy(value->name, pkt->data+12, namelen);
 664
 665         memcpy(&value->desc, &pkt->service_descr, sizeof(struct GNUNET_vpn_service_descriptor));
 666
 667         if (GNUNET_OK != GNUNET_CONTAINER_multihashmap_put(hashmap,
 668                                                            &key,
 669                                                            value,
 670                                                            GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY))
 671           {
 672             GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not store to hashmap\n");
 673           }
 674
 675         /*
 676          * Copy the newly generated backward ip-address to the packet
 677          */
 678         char* c = ((char*)pkt)+ntohs(pkt->addroffset);
 679         char* k = (char*)&key;
 680         unsigned int i;
 681         for (i = 0; i < 16; i++)
 682             c[15-i] = k[i];
 683
 684         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 685
 686         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 687
 688       }
 689     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_REV)
 690       {
 691         GNUNET_HashCode key;
 692         memset(&key, 0, sizeof key);
 693         unsigned char* k = (unsigned char*)&key;
 694         unsigned char* s = pkt->data+12;
 695         int i = 0;
 696         /* Whoever designed the reverse IPv6-lookup is batshit insane */
 697         for (i = 0; i < 16; i++)
 698           {
 699             unsigned char c1 = s[(4*i)+1];
 700             unsigned char c2 = s[(4*i)+3];
 701             if (c1 <= '9')
 702               k[i] = c1 - '0';
 703             else
 704               k[i] = c1 - 87; /* 87 is the difference between 'a' and 10 */
 705             if (c2 <= '9')
 706               k[i] += 16*(c2 - '0');
 707             else
 708               k[i] += 16*(c2 - 87);
 709           }
 710
 711         struct map_entry* map_entry = GNUNET_CONTAINER_multihashmap_get(hashmap, &key);
 712         unsigned short offset = ntohs(pkt->addroffset);
 713
 714         if (map_entry == NULL)
 715           {
 716             GNUNET_free(pkt);
 717             return;
 718           }
 719
 720         unsigned short namelen = htons(map_entry->namelen);
 721         char* name = map_entry->name;
 722
 723         list = GNUNET_malloc(2*sizeof(struct answer_packet_list*) + offset + 2 + ntohs(namelen));
 724
 725         struct answer_packet* rpkt = &list->pkt;
 726
 727         memcpy(rpkt, pkt, offset);
 728
 729         rpkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 730         rpkt->hdr.size = ntohs(offset + 2 + ntohs(namelen));
 731
 732         memcpy(((char*)rpkt)+offset, &namelen, 2);
 733         memcpy(((char*)rpkt)+offset+2, name, ntohs(namelen));
 734
 735       }
 736     else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_IP)
 737       {
 738         list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 739         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 740       }
 741     else
 742       {
 743         GNUNET_break(0);
 744         GNUNET_free(pkt);
 745         return;
 746       }
 747
 748     GNUNET_free(pkt);
 749
 750     GNUNET_CONTAINER_DLL_insert_after(answer_proc_head, answer_proc_tail, answer_proc_tail, list);
 751
 752     GNUNET_SCHEDULER_add_write_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_to_helper, &helper_write, NULL);
 753
 754     return;
 755 }
 756
 757 /**
 758  * This receives packets from the service-dns and schedules process_answer to
 759  * handle it
 760  */
 761 static void
 762 dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg) {
 763     /* the service disconnected, reconnect after short wait */
 764     if (msg == NULL)
 765       {
 766         GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
 767         dns_connection = NULL;
 768         GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
 769                                       &connect_to_service_dns,
 770                                       NULL);
 771         return;
 772       }
 773
 774     /* the service did something strange, reconnect immediately */
 775     if (msg->type != htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS))
 776       {
 777         GNUNET_break (0);
 778         GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
 779         dns_connection = NULL;
 780         GNUNET_SCHEDULER_add_now (&connect_to_service_dns,
 781                                   NULL);
 782         return;
 783       }
 784     void *pkt = GNUNET_malloc(ntohs(msg->size));
 785
 786     memcpy(pkt, msg, ntohs(msg->size));
 787
 788     GNUNET_SCHEDULER_add_now(process_answer, pkt);
 789     GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
 790 }
 791
 792 static int
 793 receive_udp (void *cls, const struct GNUNET_PeerIdentity *other,
 794              const struct GNUNET_MessageHeader *message,
 795              const struct GNUNET_TRANSPORT_ATS_Information *atsi)
 796 {
 797   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received UDP-Packet from peer %s\n",
 798               GNUNET_i2s (other));
 799   struct udp_pkt *pkt = (struct udp_pkt *) (message + 1);
 800   pkt_printf_udp (pkt);
 801   return GNUNET_OK;
 802 }
 803
 804 /**
 805  * Main function that will be run by the scheduler.
 806  *
 807  * @param cls closure
 808  * @param args remaining command-line arguments
 809  * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 810  * @param cfg configuration
 811  */
 812 static void
 813 run (void *cls,
 814      char *const *args,
 815      const char *cfgfile,
 816      const struct GNUNET_CONFIGURATION_Handle *cfg_) {
 817     const static struct GNUNET_CORE_MessageHandler handlers[] = {
 818           {receive_udp, GNUNET_MESSAGE_TYPE_SERVICE_UDP, 0},
 819           {NULL, 0, 0}
 820     };
 821     core_handle = GNUNET_CORE_connect(cfg_,
 822                                       42,
 823                                       NULL,
 824                                       NULL,
 825                                       NULL,
 826                                       NULL,
 827                                       NULL,
 828                                       NULL,
 829                                       0,
 830                                       NULL,
 831                                       0,
 832                                       handlers);
 833     mst = GNUNET_SERVER_mst_create(&message_token, NULL);
 834     cfg = cfg_;
 835     restart_hijack = 0;
 836     hashmap = GNUNET_CONTAINER_multihashmap_create(65536);
 837     GNUNET_SCHEDULER_add_now (connect_to_service_dns, NULL);
 838     GNUNET_SCHEDULER_add_now (start_helper_and_schedule, NULL);
 839     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_FOREVER_REL, &cleanup, cls);
 840 }
 841
 842 /**
 843  * The main function to obtain template from gnunetd.
 844  *
 845  * @param argc number of arguments from the command line
 846  * @param argv command line arguments
 847  * @return 0 ok, 1 on error
 848  */
 849 int
 850 main (int argc, char *const *argv) {
 851     static const struct GNUNET_GETOPT_CommandLineOption options[] = {
 852         GNUNET_GETOPT_OPTION_END
 853     };
 854
 855     return (GNUNET_OK ==
 856             GNUNET_PROGRAM_run (argc,
 857                                 argv,
 858                                 "gnunet-daemon-vpn",
 859                                 gettext_noop ("help text"),
 860                                 options, &run, NULL)) ? ret : 1;
 861 }
 862
 863 /* end of gnunet-daemon-vpn.c */