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