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 Tölke
  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_client_lib.h"
  38 #include "gnunet_container_lib.h"
  39 #include "block_dns.h"
  40
  41 /**
  42  * Final status code.
  43  */
  44 static int ret;
  45
  46 /**
  47  * The scheduler to use throughout the daemon
  48  */
  49 static struct GNUNET_SCHEDULER_Handle *sched;
  50
  51 /**
  52  * The configuration to use
  53  */
  54 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  55
  56 /**
  57  * PipeHandle to receive data from the helper
  58  */
  59 static struct GNUNET_DISK_PipeHandle* helper_in;
  60
  61 /**
  62  * PipeHandle to send data to the helper
  63  */
  64 static struct GNUNET_DISK_PipeHandle* helper_out;
  65
  66 /**
  67  * FileHandle to receive data from the helper
  68  */
  69 static const struct GNUNET_DISK_FileHandle* fh_from_helper;
  70
  71 /**
  72  * FileHandle to send data to the helper
  73  */
  74 static const struct GNUNET_DISK_FileHandle* fh_to_helper;
  75
  76 /**
  77  * The Message-Tokenizer that tokenizes the messages comming from the helper
  78  */
  79 static struct GNUNET_SERVER_MessageStreamTokenizer* mst;
  80
  81 /**
  82  * The connection to the service-dns
  83  */
  84 static struct GNUNET_CLIENT_Connection *dns_connection;
  85
  86 /**
  87  * A flag to show that the service-dns has to rehijack the outbound dns-packets
  88  *
  89  * This gets set when the helper restarts as the routing-tables are flushed when
  90  * the interface vanishes.
  91  */
  92 static unsigned char restart_hijack;
  93
  94 /**
  95  * The process id of the helper
  96  */
  97 static pid_t helper_pid;
  98
  99 /**
 100  * a list of outgoing dns-query-packets
 101  */
 102 static struct query_packet_list *head;
 103
 104 /**
 105  * The last element of the list of outgoing dns-query-packets
 106  */
 107 static struct query_packet_list *tail;
 108
 109 /**
 110  * A list of processed dns-responses.
 111  *
 112  * "processed" means that the packet is complete and can be sent out via udp
 113  * directly
 114  */
 115 static struct answer_packet_list *answer_proc_head;
 116
 117 /**
 118  * The last element of the list of processed dns-responses.
 119  */
 120 static struct answer_packet_list *answer_proc_tail;
 121
 122 size_t send_query(void* cls, size_t size, void* buf);
 123
 124 static void cleanup(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 125   GNUNET_assert (0 != (tskctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN));
 126   PLIBC_KILL(helper_pid, SIGTERM);
 127   GNUNET_OS_process_wait(helper_pid);
 128   if (dns_connection != NULL)
 129     {
 130       GNUNET_CLIENT_disconnect (dns_connection, GNUNET_NO);
 131       dns_connection = NULL;
 132     }
 133 }
 134
 135 static void helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx);
 136
 137 static void start_helper_and_schedule(void *cls,
 138                                       const struct GNUNET_SCHEDULER_TaskContext *tc) {
 139
 140         if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 141           return;
 142
 143         helper_in = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_YES, GNUNET_NO);
 144         helper_out = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_NO, GNUNET_YES);
 145
 146         if (helper_in == NULL || helper_out == NULL) return;
 147
 148         helper_pid = GNUNET_OS_start_process(helper_in, helper_out, "gnunet-helper-vpn", "gnunet-helper-vpn", NULL);
 149
 150         fh_from_helper = GNUNET_DISK_pipe_handle (helper_out, GNUNET_DISK_PIPE_END_READ);
 151         fh_to_helper = GNUNET_DISK_pipe_handle (helper_in, GNUNET_DISK_PIPE_END_WRITE);
 152
 153         GNUNET_DISK_pipe_close_end(helper_out, GNUNET_DISK_PIPE_END_WRITE);
 154         GNUNET_DISK_pipe_close_end(helper_in, GNUNET_DISK_PIPE_END_READ);
 155
 156         GNUNET_SCHEDULER_add_read_file (sched, GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 157 }
 158
 159
 160 static void restart_helper(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 161         // Kill the helper
 162         PLIBC_KILL(helper_pid, SIGKILL);
 163         GNUNET_OS_process_wait(helper_pid);
 164
 165         /* Tell the dns-service to rehijack the dns-port
 166          * The routing-table gets flushed if an interface disappears.
 167          */
 168         restart_hijack = 1;
 169         GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 170
 171         GNUNET_DISK_pipe_close(helper_in);
 172         GNUNET_DISK_pipe_close(helper_out);
 173
 174         // Restart the helper
 175         GNUNET_SCHEDULER_add_delayed (sched, GNUNET_TIME_UNIT_SECONDS, start_helper_and_schedule, NULL);
 176
 177 }
 178
 179 static void helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 180         char buf[65535];
 181
 182         if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 183                 return;
 184
 185         int t = GNUNET_DISK_file_read(fh_from_helper, &buf, 65535);
 186         if (t<=0) {
 187                 GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Read error for header from vpn-helper: %m\n");
 188                 GNUNET_SCHEDULER_add_now(sched, restart_helper, cls);
 189                 return;
 190         }
 191
 192         /* FIXME */ GNUNET_SERVER_mst_receive(mst, NULL, buf, t, 0, 0);
 193
 194         GNUNET_SCHEDULER_add_read_file (sched, GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 195 }
 196
 197 static uint16_t calculate_ip_checksum(uint16_t* hdr, short len) {
 198         uint32_t sum = 0;
 199         for(; len >= 2; len -= 2)
 200                 sum += *(hdr++);
 201         if (len == 1)
 202                 sum += *((unsigned char*)hdr);
 203
 204         sum = (sum >> 16) + (sum & 0xFFFF);
 205
 206         return ~sum;
 207 }
 208
 209 static void helper_write(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 210         if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 211                 return;
 212         struct answer_packet_list* ans = answer_proc_head;
 213         size_t len = ntohs(ans->pkt.hdr.size);
 214
 215         GNUNET_assert(ans->pkt.subtype == GNUNET_DNS_ANSWER_TYPE_IP);
 216
 217         size_t data_len = len - sizeof(struct answer_packet) + 1;
 218         size_t net_len = sizeof(struct ip_hdr) + sizeof(struct udp_dns) + data_len;
 219         size_t pkt_len = sizeof(struct GNUNET_MessageHeader) + sizeof(struct pkt_tun) + net_len;
 220
 221         struct ip_udp_dns* pkt = alloca(pkt_len);
 222         memset(pkt, 0, pkt_len);
 223
 224         pkt->shdr.size = htons(pkt_len);
 225         pkt->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 226
 227         pkt->tun.flags = 0;
 228         pkt->tun.type = htons(0x0800);
 229
 230         pkt->ip_hdr.version = 4;
 231         pkt->ip_hdr.hdr_lngth = 5;
 232         pkt->ip_hdr.diff_serv = 0;
 233         pkt->ip_hdr.tot_lngth = htons(net_len);
 234         pkt->ip_hdr.ident = 0;
 235         pkt->ip_hdr.flags = 0;
 236         pkt->ip_hdr.frag_off = 0;
 237         pkt->ip_hdr.ttl = 255;
 238         pkt->ip_hdr.proto = 0x11; /* UDP */
 239         pkt->ip_hdr.chks = 0; /* Will be calculated later*/
 240         pkt->ip_hdr.sadr = ans->pkt.from;
 241         pkt->ip_hdr.dadr = ans->pkt.to;
 242
 243         pkt->ip_hdr.chks = calculate_ip_checksum((uint16_t*)&pkt->ip_hdr, 5*4);
 244
 245         pkt->udp_dns.udp_hdr.spt = htons(53);
 246         pkt->udp_dns.udp_hdr.dpt = ans->pkt.dst_port;
 247         pkt->udp_dns.udp_hdr.len = htons(net_len - sizeof(struct ip_hdr));
 248         pkt->udp_dns.udp_hdr.crc = 0; /* Optional for IPv4 */
 249
 250         memcpy(&pkt->udp_dns.data, ans->pkt.data, data_len);
 251
 252         GNUNET_CONTAINER_DLL_remove (answer_proc_head, answer_proc_tail, ans);
 253         GNUNET_free(ans);
 254
 255         /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, pkt, pkt_len);
 256
 257         if (answer_proc_head != NULL)
 258                 GNUNET_SCHEDULER_add_write_file (sched, GNUNET_TIME_UNIT_FOREVER_REL, fh_to_helper, &helper_write, NULL);
 259 }
 260
 261 size_t send_query(void* cls, size_t size, void* buf)
 262 {
 263   size_t len;
 264   if (restart_hijack == 1)
 265     {
 266       restart_hijack = 0;
 267       GNUNET_assert(sizeof(struct GNUNET_MessageHeader) >= size);
 268       struct GNUNET_MessageHeader* hdr = buf;
 269       len = sizeof(struct GNUNET_MessageHeader);
 270       hdr->size = htons(len);
 271       hdr->type = htons(GNUNET_MESSAGE_TYPE_REHIJACK);
 272     }
 273   else
 274     {
 275         struct query_packet_list* query = head;
 276         len = ntohs(query->pkt.hdr.size);
 277
 278         GNUNET_assert(len <= size);
 279
 280         memcpy(buf, &query->pkt.hdr, len);
 281
 282         GNUNET_CONTAINER_DLL_remove (head, tail, query);
 283
 284         GNUNET_free(query);
 285     }
 286
 287         if (head != NULL || restart_hijack == 1) {
 288                 GNUNET_CLIENT_notify_transmit_ready(dns_connection, ntohs(head->pkt.hdr.size), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 289         }
 290
 291         return len;
 292 }
 293
 294 static void message_token(void *cls, void *client, const struct GNUNET_MessageHeader *message) {
 295         if (ntohs(message->type) != GNUNET_MESSAGE_TYPE_VPN_HELPER) return;
 296
 297         struct tun_pkt *pkt_tun = (struct tun_pkt*) message;
 298
 299         if (ntohs(pkt_tun->tun.type) == 0x86dd) {
 300                 struct ip6_pkt *pkt6 = (struct ip6_pkt*) message;
 301                 struct ip6_tcp *pkt6_tcp;
 302                 struct ip6_udp *pkt6_udp;
 303
 304                 pkt_printf(pkt6);
 305                 switch(pkt6->ip6_hdr.nxthdr) {
 306                         case 0x06:
 307                                 pkt6_tcp = (struct ip6_tcp*)pkt6;
 308                                 pkt_printf_ip6tcp(pkt6_tcp);
 309                                 break;
 310                         case 0x11:
 311                                 pkt6_udp = (struct ip6_udp*)pkt6;
 312                                 pkt_printf_ip6udp(pkt6_udp);
 313                                 if (ntohs(pkt6_udp->udp_hdr.dpt) == 53) {
 314                                         pkt_printf_ip6dns((struct ip6_udp_dns*)pkt6_udp);
 315                                 }
 316                                 break;
 317                 }
 318         } else if (ntohs(pkt_tun->tun.type) == 0x0800) {
 319                 struct ip_pkt *pkt = (struct ip_pkt*) message;
 320                 struct ip_udp *udp = (struct ip_udp*) message;
 321                 GNUNET_assert(pkt->ip_hdr.version == 4);
 322                 if (pkt->ip_hdr.proto == 0x11 && ntohs(udp->udp_hdr.dpt) == 53 ) {
 323                         size_t len = sizeof(struct query_packet) + ntohs(udp->udp_hdr.len) - 9; /* 9 = 8 for the udp-header + 1 for the unsigned char data[1]; */
 324                         struct query_packet_list* query = GNUNET_malloc(len + 2*sizeof(struct query_packet_list*));
 325                         query->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS);
 326                         query->pkt.hdr.size = htons(len);
 327                         query->pkt.orig_to = pkt->ip_hdr.dadr;
 328                         query->pkt.orig_from = pkt->ip_hdr.sadr;
 329                         query->pkt.src_port = udp->udp_hdr.spt;
 330                         memcpy(query->pkt.data, udp->data, ntohs(udp->udp_hdr.len) - 8);
 331
 332                         GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, query);
 333
 334                         if (dns_connection != NULL)
 335                           /* struct GNUNET_CLIENT_TransmitHandle* th = */ GNUNET_CLIENT_notify_transmit_ready(dns_connection, len, GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 336                 }
 337         }
 338
 339 }
 340
 341 static void
 342 dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg);
 343
 344 static void
 345 reconnect_to_service_dns (void *cls,
 346                           const struct GNUNET_SCHEDULER_TaskContext *tc) {
 347   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 348     return;
 349   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connecting\n");
 350   GNUNET_assert (dns_connection == NULL);
 351   dns_connection = GNUNET_CLIENT_connect (sched, "dns", cfg);
 352   GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
 353   if (head != NULL)
 354     /* struct GNUNET_CLIENT_TransmitHandle* th = */ GNUNET_CLIENT_notify_transmit_ready(dns_connection, ntohs(head->pkt.hdr.size), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 355 }
 356
 357 static void
 358 process_answer(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
 359     struct answer_packet* pkt = cls;
 360
 361     if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_SERVICE)
 362       {
 363         unsigned char ip6addr[16];
 364
 365         pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 366         memcpy(ip6addr, (int[]){htons(0x1234)}, 2);
 367         memcpy(ip6addr+2, &pkt->peer, 7);
 368         memcpy(ip6addr+9, &pkt->service_descriptor, 7);
 369
 370         memcpy(((char*)pkt)+ntohs(pkt->addroffset), ip6addr, 16);
 371
 372           /*FIXME:
 373            * -save DNS_Record into hashmap, pointed to by ip
 374            * -regularily walk through hashmap, deleting old entries
 375            *  when is an entry old?
 376            *  have a last-used field
 377            *  don't remove if last-used "recent", ask dht again if record expired
 378            */
 379       }
 380
 381         struct answer_packet_list* list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 382
 383         memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
 384
 385         GNUNET_CONTAINER_DLL_insert_after(answer_proc_head, answer_proc_tail, answer_proc_tail, list);
 386
 387         GNUNET_SCHEDULER_add_write_file (sched, GNUNET_TIME_UNIT_FOREVER_REL, fh_to_helper, &helper_write, NULL);
 388
 389         return;
 390 }
 391
 392 static void
 393 dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg)
 394 {
 395   if (msg == NULL)
 396     {
 397       GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
 398       dns_connection = NULL;
 399       GNUNET_SCHEDULER_add_delayed (sched,
 400                                     GNUNET_TIME_UNIT_SECONDS,
 401                                     &reconnect_to_service_dns,
 402                                     NULL);
 403       return;
 404     }
 405
 406   if (msg->type != htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS))
 407     {
 408       GNUNET_break (0);
 409       GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
 410       dns_connection = NULL;
 411       GNUNET_SCHEDULER_add_now (sched,
 412                                 &reconnect_to_service_dns,
 413                                 NULL);
 414       return;
 415     }
 416   void *pkt = GNUNET_malloc(ntohs(msg->size));
 417
 418   memcpy(pkt, msg, ntohs(msg->size));
 419
 420   GNUNET_SCHEDULER_add_now(sched, process_answer, pkt);
 421   GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
 422 }
 423
 424 /**
 425  * Main function that will be run by the scheduler.
 426  *
 427  * @param cls closure
 428  * @param sched the scheduler to use
 429  * @param args remaining command-line arguments
 430  * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 431  * @param cfg configuration
 432  */
 433 static void
 434 run (void *cls,
 435      struct GNUNET_SCHEDULER_Handle *sched_,
 436      char *const *args,
 437      const char *cfgfile,
 438      const struct GNUNET_CONFIGURATION_Handle *cfg_)
 439 {
 440   sched = sched_;
 441   mst = GNUNET_SERVER_mst_create(&message_token, NULL);
 442   cfg = cfg_;
 443   restart_hijack = 0;
 444   GNUNET_SCHEDULER_add_now (sched, &reconnect_to_service_dns, NULL);
 445   GNUNET_SCHEDULER_add_delayed(sched, GNUNET_TIME_UNIT_FOREVER_REL, &cleanup, cls);
 446   GNUNET_SCHEDULER_add_now (sched, start_helper_and_schedule, NULL);
 447 }
 448
 449
 450 /**
 451  * The main function to obtain template from gnunetd.
 452  *
 453  * @param argc number of arguments from the command line
 454  * @param argv command line arguments
 455  * @return 0 ok, 1 on error
 456  */
 457 int
 458 main (int argc, char *const *argv)
 459 {
 460   static const struct GNUNET_GETOPT_CommandLineOption options[] = {
 461     GNUNET_GETOPT_OPTION_END
 462   };
 463
 464   return (GNUNET_OK ==
 465           GNUNET_PROGRAM_run (argc,
 466                               argv,
 467                               "gnunet-daemon-vpn",
 468                               gettext_noop ("help text"),
 469                               options, &run, NULL)) ? ret : 1;
 470 }
 471
 472 /* end of gnunet-daemon-vpn.c */