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