src/vpn/gnunet-daemon-vpn-helper.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-helper.c
  23  * @brief
  24  * @author Philipp Toelke
  25  */
  26 #include <platform.h>
  27 #include <gnunet_common.h>
  28 #include <gnunet_client_lib.h>
  29 #include <gnunet_os_lib.h>
  30 #include <gnunet_mesh_service.h>
  31 #include <gnunet_protocols.h>
  32 #include <gnunet_server_lib.h>
  33 #include <gnunet_container_lib.h>
  34 #include <block_dns.h>
  35 #include <gnunet_configuration_lib.h>
  36
  37 #include "gnunet-daemon-vpn-dns.h"
  38 #include "gnunet-daemon-vpn.h"
  39 #include "gnunet-daemon-vpn-helper.h"
  40 #include "gnunet-service-dns-p.h"
  41 #include "gnunet-vpn-packet.h"
  42
  43 /**
  44  * PipeHandle to receive data from the helper
  45  */
  46 static struct GNUNET_DISK_PipeHandle* helper_in;
  47
  48 /**
  49  * PipeHandle to send data to the helper
  50  */
  51 static struct GNUNET_DISK_PipeHandle* helper_out;
  52
  53 /**
  54  * FileHandle to receive data from the helper
  55  */
  56 static const struct GNUNET_DISK_FileHandle* fh_from_helper;
  57
  58 /**
  59  * FileHandle to send data to the helper
  60  */
  61 static const struct GNUNET_DISK_FileHandle* fh_to_helper;
  62
  63 /**
  64  * Start the helper-process
  65  * {{{
  66  */
  67 void
  68 start_helper_and_schedule(void *cls,
  69                           const struct GNUNET_SCHEDULER_TaskContext *tc) {
  70     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
  71       return;
  72
  73     helper_in = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_YES, GNUNET_NO);
  74     helper_out = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_NO, GNUNET_YES);
  75
  76     if (helper_in == NULL || helper_out == NULL) return;
  77
  78     char* ipv6addr;
  79     char* ipv6prefix;
  80     char* ipv4addr;
  81     char* ipv4mask;
  82
  83     if (GNUNET_SYSERR == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr))
  84       {
  85         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "No entry 'IPV6ADDR' in configuration!\n");
  86         exit(1);
  87       }
  88
  89     if (GNUNET_SYSERR == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6PREFIX", &ipv6prefix))
  90       {
  91         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "No entry 'IPV6PREFIX' in configuration!\n");
  92         exit(1);
  93       }
  94
  95     if (GNUNET_SYSERR == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV4ADDR", &ipv4addr))
  96       {
  97         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "No entry 'IPV4ADDR' in configuration!\n");
  98         exit(1);
  99       }
 100
 101     if (GNUNET_SYSERR == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV4MASK", &ipv4mask))
 102       {
 103         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "No entry 'IPV4MASK' in configuration!\n");
 104         exit(1);
 105       }
 106
 107     helper_proc =
 108       GNUNET_OS_start_process (helper_in, helper_out, "gnunet-helper-vpn",
 109                                "gnunet-helper-vpn", ipv6addr, ipv6prefix,
 110                                ipv4addr, ipv4mask, NULL);
 111
 112     GNUNET_free(ipv6addr);
 113     GNUNET_free(ipv6prefix);
 114     GNUNET_free(ipv4addr);
 115     GNUNET_free(ipv4mask);
 116
 117     fh_from_helper = GNUNET_DISK_pipe_handle (helper_out, GNUNET_DISK_PIPE_END_READ);
 118     fh_to_helper = GNUNET_DISK_pipe_handle (helper_in, GNUNET_DISK_PIPE_END_WRITE);
 119
 120     GNUNET_DISK_pipe_close_end(helper_out, GNUNET_DISK_PIPE_END_WRITE);
 121     GNUNET_DISK_pipe_close_end(helper_in, GNUNET_DISK_PIPE_END_READ);
 122
 123     /* Tell the dns-service to rehijack the dns-port
 124      * The routing-table gets flushed if an interface disappears.
 125      */
 126     restart_hijack = 1;
 127     GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
 128
 129     GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 130 }
 131 /*}}}*/
 132 /**
 133  * Restart the helper-process
 134  * {{{
 135  */
 136 void
 137 restart_helper(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tskctx) {
 138     // Kill the helper
 139     GNUNET_OS_process_kill (helper_proc, SIGKILL);
 140     GNUNET_OS_process_wait (helper_proc);
 141     GNUNET_OS_process_close (helper_proc);
 142     helper_proc = NULL;
 143
 144     GNUNET_DISK_pipe_close(helper_in);
 145     GNUNET_DISK_pipe_close(helper_out);
 146
 147     /* Restart the helper */
 148     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, start_helper_and_schedule, NULL);
 149 }
 150 /*}}}*/
 151
 152 /**
 153  * Read from the helper-process
 154  * {{{
 155  */
 156 void
 157 helper_read(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 158     /* no message can be bigger then 64k */
 159     char buf[65535];
 160
 161     if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 162       return;
 163
 164     int t = GNUNET_DISK_file_read(fh_from_helper, &buf, 65535);
 165
 166     /* On read-error, restart the helper */
 167     if (t<=0) {
 168         GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Read error for header from vpn-helper: %m\n");
 169         GNUNET_SCHEDULER_add_now(restart_helper, cls);
 170         return;
 171     }
 172
 173     /* FIXME */ GNUNET_SERVER_mst_receive(mst, NULL, buf, t, 0, 0);
 174
 175     GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, fh_from_helper, &helper_read, NULL);
 176 }
 177 /*}}}*/
 178
 179 /**
 180  * Send an dns-answer-packet to the helper
 181  */
 182 void
 183 helper_write(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tsdkctx) {
 184     if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 185       return;
 186
 187     struct answer_packet_list* ans = answer_proc_head;
 188     size_t len = ntohs(ans->pkt.hdr.size);
 189
 190     GNUNET_assert(ans->pkt.subtype == GNUNET_DNS_ANSWER_TYPE_IP);
 191
 192     GNUNET_assert (20 == sizeof (struct ip_hdr));
 193     GNUNET_assert (8 == sizeof (struct udp_pkt));
 194     size_t data_len = len - sizeof(struct answer_packet) + 1;
 195     size_t net_len = sizeof(struct ip_hdr) + sizeof(struct udp_dns) + data_len;
 196     size_t pkt_len = sizeof(struct GNUNET_MessageHeader) + sizeof(struct pkt_tun) + net_len;
 197
 198     struct ip_udp_dns* pkt = alloca(pkt_len);
 199     GNUNET_assert(pkt != NULL);
 200     memset(pkt, 0, pkt_len);
 201
 202     /* set the gnunet-header */
 203     pkt->shdr.size = htons(pkt_len);
 204     pkt->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
 205
 206     /* set the tun-header (no flags and ethertype of IPv4) */
 207     pkt->tun.flags = 0;
 208     pkt->tun.type = htons(0x0800);
 209
 210     /* set the ip-header */
 211     pkt->ip_hdr.version = 4;
 212     pkt->ip_hdr.hdr_lngth = 5;
 213     pkt->ip_hdr.diff_serv = 0;
 214     pkt->ip_hdr.tot_lngth = htons(net_len);
 215     pkt->ip_hdr.ident = 0;
 216     pkt->ip_hdr.flags = 0;
 217     pkt->ip_hdr.frag_off = 0;
 218     pkt->ip_hdr.ttl = 255;
 219     pkt->ip_hdr.proto = 0x11; /* UDP */
 220     pkt->ip_hdr.chks = 0; /* Will be calculated later*/
 221     pkt->ip_hdr.sadr = ans->pkt.from;
 222     pkt->ip_hdr.dadr = ans->pkt.to;
 223
 224     pkt->ip_hdr.chks = calculate_ip_checksum((uint16_t*)&pkt->ip_hdr, 5*4);
 225
 226     /* set the udp-header */
 227     pkt->udp_dns.udp_hdr.spt = htons(53);
 228     pkt->udp_dns.udp_hdr.dpt = ans->pkt.dst_port;
 229     pkt->udp_dns.udp_hdr.len = htons(net_len - sizeof(struct ip_hdr));
 230     pkt->udp_dns.udp_hdr.crc = 0; /* Optional for IPv4 */
 231
 232     memcpy(&pkt->udp_dns.data, ans->pkt.data, data_len);
 233
 234     GNUNET_CONTAINER_DLL_remove (answer_proc_head, answer_proc_tail, ans);
 235     GNUNET_free(ans);
 236
 237     /* FIXME */ GNUNET_DISK_file_write(fh_to_helper, pkt, pkt_len);
 238
 239     /* if more packets are available, reschedule */
 240     if (answer_proc_head != NULL)
 241       GNUNET_SCHEDULER_add_write_file (GNUNET_TIME_UNIT_FOREVER_REL,
 242                                        fh_to_helper,
 243                                        &helper_write,
 244                                        NULL);
 245 }
 246 /**
 247  * Receive packets from the helper-process
 248  */
 249 void
 250 message_token(void *cls,
 251               void *client,
 252               const struct GNUNET_MessageHeader *message) {
 253     GNUNET_assert(ntohs(message->type) == GNUNET_MESSAGE_TYPE_VPN_HELPER);
 254
 255     struct tun_pkt *pkt_tun = (struct tun_pkt*) message;
 256
 257     /* ethertype is ipv6 */
 258     if (ntohs(pkt_tun->tun.type) == 0x86dd)
 259       {
 260         struct ip6_pkt *pkt6 = (struct ip6_pkt*) message;
 261         GNUNET_assert(pkt6->ip6_hdr.version == 6);
 262         struct ip6_tcp *pkt6_tcp;
 263         struct ip6_udp *pkt6_udp;
 264         struct ip6_icmp *pkt6_icmp;
 265         GNUNET_HashCode* key;
 266
 267         switch(pkt6->ip6_hdr.nxthdr)
 268           {
 269           case 0x06:
 270             pkt6_tcp = (struct ip6_tcp*)pkt6;
 271             break;
 272           case 0x11:
 273             pkt6_udp = (struct ip6_udp*)pkt6;
 274             if ((key = address_mapping_exists(pkt6->ip6_hdr.dadr)) != NULL)
 275               {
 276                 struct map_entry* me = GNUNET_CONTAINER_multihashmap_get(hashmap, key);
 277                 GNUNET_assert(me != NULL);
 278                 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Mapping exists; type: %d; UDP is %d; port: %x/%x!\n", me->desc.service_type, htonl(GNUNET_DNS_SERVICE_TYPE_UDP), pkt6_udp->udp_hdr.dpt, me->desc.ports);
 279                 GNUNET_free(key);
 280                 if (me->desc.service_type & htonl(GNUNET_DNS_SERVICE_TYPE_UDP) &&
 281                     (port_in_ports(me->desc.ports, pkt6_udp->udp_hdr.dpt) ||
 282                      port_in_ports(me->additional_ports, pkt6_udp->udp_hdr.dpt)))
 283                   {
 284                     size_t size = sizeof(struct GNUNET_MESH_Tunnel*) + sizeof(struct GNUNET_MessageHeader) + sizeof(GNUNET_HashCode) + ntohs(pkt6_udp->udp_hdr.len);
 285                     struct GNUNET_MESH_Tunnel **cls = GNUNET_malloc(size);
 286                     struct GNUNET_MessageHeader *hdr = (struct GNUNET_MessageHeader*)(cls+1);
 287                     GNUNET_HashCode* hc = (GNUNET_HashCode*)(hdr + 1);
 288
 289                     memcpy(hc, &me->desc.service_descriptor, sizeof(GNUNET_HashCode));
 290                     memcpy(hc+1, &pkt6_udp->udp_hdr, ntohs(pkt6_udp->udp_hdr.len));
 291
 292                     if (me->tunnel == NULL)
 293                       {
 294                         *cls = GNUNET_MESH_peer_request_connect_all(mesh_handle,
 295                                                                     GNUNET_TIME_UNIT_FOREVER_REL,
 296                                                                     1,
 297                                                                     (struct GNUNET_PeerIdentity*)&me->desc.peer,
 298                                                                     send_udp_to_peer,
 299                                                                     NULL,
 300                                                                     cls);
 301                         me->tunnel = *cls;
 302                       }
 303                     else
 304                       {
 305                         *cls = me->tunnel;
 306                         send_udp_to_peer(cls, (struct GNUNET_PeerIdentity*)1, NULL);
 307                       }
 308                     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Queued to send to peer %x\n", *((unsigned int*)&me->desc.peer));
 309                   }
 310               }
 311             break;
 312           case 0x3a:
 313             /* ICMPv6 */
 314             pkt6_icmp = (struct ip6_icmp*)pkt6;
 315             /* If this packet is an icmp-echo-request and a mapping exists, answer */
 316             if (pkt6_icmp->icmp_hdr.type == 0x80 && (key = address_mapping_exists(pkt6->ip6_hdr.dadr)) != NULL)
 317               {
 318                 GNUNET_free(key);
 319                 pkt6_icmp = GNUNET_malloc(ntohs(pkt6->shdr.size));
 320                 memcpy(pkt6_icmp, pkt6, ntohs(pkt6->shdr.size));
 321                 GNUNET_SCHEDULER_add_now(&send_icmp_response, pkt6_icmp);
 322               }
 323             break;
 324           }
 325       }
 326     /* ethertype is ipv4 */
 327     else if (ntohs(pkt_tun->tun.type) == 0x0800)
 328       {
 329         struct ip_pkt *pkt = (struct ip_pkt*) message;
 330         struct ip_udp *udp = (struct ip_udp*) message;
 331         GNUNET_assert(pkt->ip_hdr.version == 4);
 332
 333         /* Send dns-packets to the service-dns */
 334         if (pkt->ip_hdr.proto == 0x11 && ntohs(udp->udp_hdr.dpt) == 53 )
 335           {
 336             /* 9 = 8 for the udp-header + 1 for the unsigned char data[1]; */
 337             size_t len = sizeof(struct query_packet) + ntohs(udp->udp_hdr.len) - 9;
 338
 339             struct query_packet_list* query = GNUNET_malloc(len + 2*sizeof(struct query_packet_list*));
 340             query->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS);
 341             query->pkt.hdr.size = htons(len);
 342             query->pkt.orig_to = pkt->ip_hdr.dadr;
 343             query->pkt.orig_from = pkt->ip_hdr.sadr;
 344             query->pkt.src_port = udp->udp_hdr.spt;
 345             memcpy(query->pkt.data, udp->data, ntohs(udp->udp_hdr.len) - 8);
 346
 347             GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, query);
 348
 349             GNUNET_assert(head != NULL);
 350
 351             if (dns_connection != NULL)
 352               GNUNET_CLIENT_notify_transmit_ready(dns_connection,
 353                                                   len,
 354                                                   GNUNET_TIME_UNIT_FOREVER_REL,
 355                                                   GNUNET_YES,
 356                                                   &send_query,
 357                                                   NULL);
 358           }
 359       }
 360 }
 361
 362 void write_to_helper(void* buf, size_t len)
 363 {
 364   (void)GNUNET_DISK_file_write(fh_to_helper, buf, len);
 365 }
 366
 367 void schedule_helper_write(struct GNUNET_TIME_Relative time, void* cls)
 368 {
 369   GNUNET_SCHEDULER_add_write_file (time, fh_to_helper, &helper_write, cls);
 370 }