src/6to4.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2011  Nokia Corporation. All rights reserved.
   6  *  Copyright (C) Alexey Kuznetsov et al. from iproute2 package.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20  *
  21  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <sys/socket.h>
  32 #include <netinet/in.h>
  33 #include <arpa/inet.h>
  34 #include <net/if.h>
  35 #include <linux/ip.h>
  36 #include <linux/if_tunnel.h>
  37 #include <linux/netlink.h>
  38 #include <linux/rtnetlink.h>
  39 #include <sys/ioctl.h>
  40 #include <unistd.h>
  41
  42 #include "connman.h"
  43 #include <connman/log.h>
  44 #include <connman/ipconfig.h>
  45 #include "gweb/gweb.h"
  46
  47 static int tunnel_created;
  48 static int tunnel_pending;
  49 static char *tunnel_ip_address;
  50 static GWeb *web;
  51 static guint web_request_id;
  52 static unsigned int newlink_watch;
  53 static unsigned int newlink_flags;
  54 static int newlink_timeout_id;
  55
  56 #define STATUS_URL "http://ipv6.connman.net/online/status.html"
  57
  58 #ifndef IP_DF
  59 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  60 #endif
  61
  62 static int tunnel_create(struct in_addr *addr)
  63 {
  64         struct ip_tunnel_parm p;
  65         struct ifreq ifr;
  66         int fd = -1;
  67         int ret;
  68
  69         /* ip tunnel add tun6to4 mode sit remote any local 1.2.3.4 ttl 64 */
  70
  71         memset(&p, 0, sizeof(struct ip_tunnel_parm));
  72         memset(&ifr, 0, sizeof(struct ifreq));
  73
  74         p.iph.version = 4;
  75         p.iph.ihl = 5;
  76         p.iph.frag_off = htons(IP_DF);
  77         p.iph.protocol = IPPROTO_IPV6;
  78         p.iph.saddr = addr->s_addr;
  79         p.iph.ttl = 64;
  80         strncpy(p.name, "tun6to4", IFNAMSIZ);
  81
  82         strncpy(ifr.ifr_name, "sit0", IFNAMSIZ);
  83         ifr.ifr_ifru.ifru_data = (void *)&p;
  84         fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
  85         ret = ioctl(fd, SIOCADDTUNNEL, &ifr);
  86         if (ret)
  87                 connman_error("add tunnel %s failed: %s", ifr.ifr_name,
  88                                                         strerror(errno));
  89         close(fd);
  90
  91         return ret;
  92 }
  93
  94 static void tunnel_destroy()
  95 {
  96         struct ip_tunnel_parm p;
  97         struct ifreq ifr;
  98         int fd = -1;
  99         int ret;
 100
 101         if (tunnel_created == 0)
 102                 return;
 103
 104         /* ip tunnel del tun6to4 */
 105
 106         memset(&p, 0, sizeof(struct ip_tunnel_parm));
 107         memset(&ifr, 0, sizeof(struct ifreq));
 108
 109         p.iph.version = 4;
 110         p.iph.ihl = 5;
 111         p.iph.protocol = IPPROTO_IPV6;
 112         strncpy(p.name, "tun6to4", IFNAMSIZ);
 113
 114         strncpy(ifr.ifr_name, "tun6to4", IFNAMSIZ);
 115         ifr.ifr_ifru.ifru_data = (void *)&p;
 116         fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 117         if (fd < 0) {
 118                 connman_error("socket failed: %s", strerror(errno));
 119                 return;
 120         }
 121
 122         ret = ioctl(fd, SIOCDELTUNNEL, &ifr);
 123         if (ret)
 124                 connman_error("del tunnel %s failed: %s", ifr.ifr_name,
 125                                                         strerror(errno));
 126         else
 127                 tunnel_created = 0;
 128
 129         tunnel_pending = 0;
 130         close(fd);
 131
 132         g_free(tunnel_ip_address);
 133         tunnel_ip_address = NULL;
 134 }
 135
 136 static int tunnel_add_route()
 137 {
 138         struct __connman_inet_rtnl_handle rth;
 139         struct in6_addr addr6;
 140         int index;
 141         int ret = 0;
 142
 143         /* ip -6 route add ::/0 via ::192.88.99.1 dev tun6to4 metric 1 */
 144
 145         index = if_nametoindex("tun6to4");
 146         if (index == 0) {
 147                 DBG("Can not find device tun6to4");
 148                 return -1;
 149         }
 150
 151         memset(&rth, 0, sizeof(rth));
 152
 153         rth.req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 154         rth.req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
 155         rth.req.n.nlmsg_type = RTM_NEWROUTE;
 156         rth.req.u.r.rt.rtm_family = AF_INET6;
 157         rth.req.u.r.rt.rtm_table = RT_TABLE_MAIN;
 158         rth.req.u.r.rt.rtm_protocol = RTPROT_BOOT;
 159         rth.req.u.r.rt.rtm_scope = RT_SCOPE_UNIVERSE;
 160         rth.req.u.r.rt.rtm_type = RTN_UNICAST;
 161         rth.req.u.r.rt.rtm_dst_len = 0;
 162
 163         inet_pton(AF_INET6, "::192.88.99.1", &addr6);
 164
 165         __connman_inet_rtnl_addattr_l(&rth.req.n, sizeof(rth.req), RTA_GATEWAY,
 166                                         &addr6.s6_addr, 16);
 167         __connman_inet_rtnl_addattr32(&rth.req.n, sizeof(rth.req), RTA_OIF,
 168                                         index);
 169         __connman_inet_rtnl_addattr32(&rth.req.n, sizeof(rth.req),
 170                                         RTA_PRIORITY, 1);
 171
 172         ret = __connman_inet_rtnl_open(&rth);
 173         if (ret < 0)
 174                 goto done;
 175
 176         ret = __connman_inet_rtnl_send(&rth, &rth.req.n);
 177
 178 done:
 179         __connman_inet_rtnl_close(&rth);
 180         return ret;
 181 }
 182
 183 static int tunnel_set_addr(unsigned int a, unsigned int b,
 184                         unsigned int c, unsigned int d)
 185 {
 186         struct __connman_inet_rtnl_handle rth;
 187         struct in6_addr addr6;
 188         char *ip6addr;
 189         int ret;
 190
 191         /* ip -6 addr add dev tun6to4 2002:0102:0304::1/64 */
 192
 193         memset(&rth, 0, sizeof(rth));
 194
 195         rth.req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
 196         rth.req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
 197         rth.req.n.nlmsg_type = RTM_NEWADDR;
 198         rth.req.u.i.ifa.ifa_family = AF_INET6;
 199         rth.req.u.i.ifa.ifa_prefixlen = 64;
 200         rth.req.u.i.ifa.ifa_index = if_nametoindex("tun6to4");
 201         if (rth.req.u.i.ifa.ifa_index == 0) {
 202                 connman_error("Can not find device tun6to4");
 203                 ret = -1;
 204                 goto done;
 205         }
 206
 207         ip6addr = g_strdup_printf("2002:%02x%02x:%02x%02x::1", a, b, c, d);
 208         inet_pton(AF_INET6, ip6addr, &addr6);
 209         DBG("ipv6 address %s", ip6addr);
 210         g_free(ip6addr);
 211
 212         __connman_inet_rtnl_addattr_l(&rth.req.n, sizeof(rth.req), IFA_LOCAL,
 213                                         &addr6.s6_addr, 16);
 214         __connman_inet_rtnl_addattr_l(&rth.req.n, sizeof(rth.req), IFA_ADDRESS,
 215                                         &addr6.s6_addr, 16);
 216
 217         ret = __connman_inet_rtnl_open(&rth);
 218         if (ret < 0)
 219                 goto done;
 220
 221         ret = __connman_inet_rtnl_send(&rth, &rth.req.n);
 222
 223 done:
 224         __connman_inet_rtnl_close(&rth);
 225         return ret;
 226 }
 227
 228 static gboolean unref_web(gpointer user_data)
 229 {
 230         g_web_unref(web);
 231         return FALSE;
 232 }
 233
 234 static gboolean web_result(GWebResult *result, gpointer user_data)
 235 {
 236         guint16 status;
 237
 238         if (web_request_id == 0)
 239                 return FALSE;
 240
 241         status = g_web_result_get_status(result);
 242
 243         DBG("status %u", status);
 244
 245         if (status >= 400 && status < 500)
 246                 tunnel_destroy();
 247         else
 248                 tunnel_pending = 0;
 249
 250         web_request_id = 0;
 251
 252         g_timeout_add_seconds(1, unref_web, NULL);
 253
 254         return FALSE;
 255 }
 256
 257 static void web_debug(const char *str, void *data)
 258 {
 259         connman_info("%s: %s\n", (const char *) data, str);
 260 }
 261
 262 static gboolean newlink_timeout(gpointer user_data)
 263 {
 264         /*
 265          * Stop if the timeout has been cancelled already by tun_newlink()
 266          */
 267         if (newlink_timeout_id == 0)
 268                 return FALSE;
 269
 270         DBG("");
 271
 272         if (newlink_watch != 0) {
 273                 connman_rtnl_remove_watch(newlink_watch);
 274                 newlink_watch = 0;
 275         }
 276
 277         newlink_flags = 0;
 278
 279         if (web_request_id == 0)
 280                 tunnel_destroy();
 281
 282         newlink_timeout_id = 0;
 283
 284         return FALSE;
 285 }
 286
 287 static void tun_newlink(unsigned flags, unsigned change, void *user_data)
 288 {
 289         int index = GPOINTER_TO_INT(user_data);
 290
 291         if ((newlink_flags & IFF_UP) == (flags & IFF_UP)) {
 292                 newlink_flags = flags;
 293                 return;
 294         }
 295
 296         if (flags & IFF_UP) {
 297                 /*
 298                  * We try to verify that connectivity through tunnel works ok.
 299                  */
 300                 if (newlink_timeout_id > 0) {
 301                         g_source_remove(newlink_timeout_id);
 302                         newlink_timeout_id = 0;
 303                 }
 304
 305                 web = g_web_new(index);
 306                 if (web == NULL) {
 307                         tunnel_destroy();
 308                         return;
 309                 }
 310
 311                 g_web_set_accept(web, NULL);
 312                 g_web_set_user_agent(web, "ConnMan/%s", VERSION);
 313                 g_web_set_close_connection(web, TRUE);
 314
 315                 if (getenv("CONNMAN_WEB_DEBUG"))
 316                         g_web_set_debug(web, web_debug, "6to4");
 317
 318                 web_request_id = g_web_request_get(web, STATUS_URL,
 319                                                 web_result, NULL);
 320
 321                 newlink_timeout(NULL);
 322         }
 323
 324         newlink_flags = flags;
 325 }
 326
 327 static int init_6to4(struct in_addr *ip4addr)
 328 {
 329         unsigned int a, b, c, d;
 330         int ret, if_index;
 331         in_addr_t addr;
 332
 333         DBG("");
 334
 335         addr = ntohl(ip4addr->s_addr);
 336
 337         a = (addr & 0xff000000) >> 24;
 338         b = (addr & 0x00ff0000) >> 16;
 339         c = (addr & 0x0000ff00) >> 8;
 340         d = addr & 0x000000ff;
 341
 342         ret = tunnel_create(ip4addr);
 343         if (ret)
 344                 return -1;
 345
 346         tunnel_created = 1;
 347
 348         ret = connman_inet_setup_tunnel("tun6to4", 1472);
 349         if (ret)
 350                 goto error;
 351
 352         ret = tunnel_set_addr(a, b, c, d);
 353         if (ret)
 354                 goto error;
 355
 356         ret = tunnel_add_route();
 357         if (ret)
 358                 goto error;
 359
 360         if_index = connman_inet_ifindex("tun6to4");
 361         if (if_index < 0)
 362                 goto error;
 363
 364         newlink_watch = connman_rtnl_add_newlink_watch(if_index,
 365                                 tun_newlink, GINT_TO_POINTER(if_index));
 366
 367         newlink_timeout_id = g_timeout_add_seconds(1, newlink_timeout, NULL);
 368
 369         return 0;
 370
 371 error:
 372         tunnel_destroy();
 373         return -1;
 374 }
 375
 376 static void receive_rs_reply(struct nd_router_advert *reply,
 377                         unsigned int length, void *user_data)
 378 {
 379         char *address = user_data;
 380         struct in_addr ip4addr;
 381
 382         DBG("reply %p len %d address %s", reply, length, address);
 383
 384         /* We try to create tunnel if autoconfiguration did not work i.e.,
 385          * we did not receive any reply to router solicitation message.
 386          */
 387         if (reply == NULL && inet_aton(address, &ip4addr) != 0)
 388                 init_6to4(&ip4addr);
 389
 390         g_free(address);
 391 }
 392
 393 int __connman_6to4_probe(struct connman_service *service)
 394 {
 395         struct connman_ipconfig *ip4config, *ip6config;
 396         enum connman_ipconfig_method method;
 397         unsigned int a, b;
 398         struct in_addr ip4addr;
 399         in_addr_t addr;
 400         const char *address;
 401         char *ip_address;
 402         int index;
 403
 404         DBG("service %p", service);
 405
 406         if (tunnel_created || tunnel_pending)
 407                 return 0;
 408
 409         if (service == NULL)
 410                 return -1;
 411
 412         ip4config = __connman_service_get_ip4config(service);
 413         if (ip4config == NULL)
 414                 return -1;
 415
 416         ip6config = __connman_service_get_ip6config(service);
 417         if (ip6config == NULL)
 418                 return -1;
 419
 420         method = __connman_ipconfig_get_method(ip6config);
 421         if (method != CONNMAN_IPCONFIG_METHOD_AUTO)
 422                 return -1;
 423
 424         address = __connman_ipconfig_get_local(ip4config);
 425         if (address == NULL)
 426                 return -1;
 427
 428         if (inet_aton(address, &ip4addr) == 0)
 429                 return -1;
 430
 431         addr = ntohl(ip4addr.s_addr);
 432
 433         a = (addr & 0xff000000) >> 24;
 434         b = (addr & 0x00ff0000) >> 16;
 435
 436         /* 6to4 tunnel is only usable if we have a public IPv4 address */
 437         if (a == 10 || (a == 192 && b == 168) ||
 438                                         (a == 172 && (b >= 16 && b <= 31)))
 439                 return -1;
 440
 441         index = __connman_ipconfig_get_index(ip4config);
 442         ip_address = g_strdup(address);
 443         tunnel_pending = 1;
 444
 445         g_free(tunnel_ip_address);
 446         tunnel_ip_address = g_strdup(address);
 447
 448         return __connman_inet_ipv6_send_rs(index, 2, receive_rs_reply,
 449                                                         ip_address);
 450 }
 451
 452 void __connman_6to4_remove(struct connman_ipconfig *ip4config)
 453 {
 454         const char *address;
 455
 456         DBG("tunnel ip address %s", tunnel_ip_address);
 457
 458         if (ip4config == NULL)
 459                 return;
 460
 461         address = __connman_ipconfig_get_local(ip4config);
 462         if (address == NULL)
 463                 return;
 464
 465         if (g_strcmp0(address, tunnel_ip_address) != 0)
 466                 return;
 467
 468         if (tunnel_created)
 469                 tunnel_destroy();
 470 }
 471
 472 int __connman_6to4_check(struct connman_ipconfig *ip4config)
 473 {
 474         const char *address;
 475
 476         if (ip4config == NULL || tunnel_created == 0 ||
 477                                         tunnel_pending == 1)
 478                 return -1;
 479
 480         DBG("tunnel ip address %s", tunnel_ip_address);
 481
 482         address = __connman_ipconfig_get_local(ip4config);
 483         if (address == NULL)
 484                 return -1;
 485
 486         if (g_strcmp0(address, tunnel_ip_address) == 0)
 487                 return 1;
 488
 489         return 0;
 490 }