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