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