mdw@git.distorted.org.uk Git - secnet/blob - tun.c

   1 #include "secnet.h"
   2 #include "util.h"
   3 #include "netlink.h"
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <fcntl.h>
   8 #include <sys/ioctl.h>
   9 #include <sys/utsname.h>
  10 #include <sys/socket.h>
  11
  12 #ifdef HAVE_NET_IF_H
  13 #include <net/if.h>
  14 #ifdef HAVE_LINUX_IF_H
  15 #include <linux/if_tun.h>
  16 #define LINUX_TUN_SUPPORTED
  17 #endif
  18 #endif
  19
  20 #ifdef HAVE_NET_ROUTE_H
  21 #include <net/route.h>
  22 #endif
  23
  24 #if defined(HAVE_STROPTS_H) && defined(HAVE_SYS_SOCKIO_H) && \
  25 defined(HAVE_NET_IF_TUN_H)
  26 #define HAVE_TUN_STREAMS
  27 #endif
  28
  29 #ifdef HAVE_TUN_STREAMS
  30 #include <stropts.h>
  31 #include <sys/sockio.h>
  32 #include <net/if_tun.h>
  33 #endif
  34
  35 #define TUN_FLAVOUR_GUESS   0
  36 #define TUN_FLAVOUR_BSD     1
  37 #define TUN_FLAVOUR_LINUX   2
  38 #define TUN_FLAVOUR_STREAMS 3
  39
  40 static struct flagstr flavours[]={
  41     {"guess", TUN_FLAVOUR_GUESS},
  42     {"bsd", TUN_FLAVOUR_BSD},
  43     {"BSD", TUN_FLAVOUR_BSD},
  44     {"linux", TUN_FLAVOUR_LINUX},
  45     {"streams", TUN_FLAVOUR_STREAMS},
  46     {"STREAMS", TUN_FLAVOUR_STREAMS},
  47     {NULL, 0}
  48 };
  49
  50 #define TUN_CONFIG_GUESS      0
  51 #define TUN_CONFIG_IOCTL      1
  52 #define TUN_CONFIG_BSD        2
  53 #define TUN_CONFIG_LINUX      3
  54 #define TUN_CONFIG_SOLARIS25  4
  55
  56 static struct flagstr config_types[]={
  57     {"guess", TUN_CONFIG_GUESS},
  58     {"ioctl", TUN_CONFIG_IOCTL},
  59     {"bsd", TUN_CONFIG_BSD},
  60     {"BSD", TUN_CONFIG_BSD},
  61     {"linux", TUN_CONFIG_LINUX},
  62     {"solaris-2.5", TUN_CONFIG_SOLARIS25},
  63     {NULL, 0}
  64 };
  65
  66 /* Connection to the kernel through the universal TUN/TAP driver */
  67
  68 struct tun {
  69     struct netlink nl;
  70     int fd;
  71     cstring_t device_path;
  72     cstring_t ip_path;
  73     string_t interface_name;
  74     cstring_t ifconfig_path;
  75     uint32_t ifconfig_type;
  76     cstring_t route_path;
  77     uint32_t route_type;
  78     uint32_t tun_flavour;
  79     bool_t search_for_if; /* Applies to tun-BSD only */
  80     struct buffer_if *buff; /* We receive packets into here
  81                                and send them to the netlink code. */
  82     netlink_deliver_fn *netlink_to_tunnel;
  83     uint32_t local_address; /* host interface address */
  84 };
  85
  86 static cstring_t tun_flavour_str(uint32_t flavour)
  87 {
  88     switch (flavour) {
  89     case TUN_FLAVOUR_GUESS: return "guess";
  90     case TUN_FLAVOUR_BSD: return "BSD";
  91     case TUN_FLAVOUR_LINUX: return "linux";
  92     case TUN_FLAVOUR_STREAMS: return "STREAMS";
  93     default: return "unknown";
  94     }
  95 }
  96
  97 static int tun_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
  98                           int *timeout_io, const struct timeval *tv_now,
  99                           uint64_t *now)
 100 {
 101     struct tun *st=sst;
 102     *nfds_io=1;
 103     fds[0].fd=st->fd;
 104     fds[0].events=POLLIN;
 105     return 0;
 106 }
 107
 108 static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds,
 109                           const struct timeval *tv_now, uint64_t *now)
 110 {
 111     struct tun *st=sst;
 112     int l;
 113
 114     if (nfds==0) return;
 115     if (fds[0].revents&POLLERR) {
 116         printf("tun_afterpoll: hup!\n");
 117     }
 118     if (fds[0].revents&POLLIN) {
 119         BUF_ALLOC(st->buff,"tun_afterpoll");
 120         buffer_init(st->buff,st->nl.max_start_pad);
 121         l=read(st->fd,st->buff->start,st->buff->len-st->nl.max_start_pad);
 122         if (l<0) {
 123             fatal_perror("tun_afterpoll: read()");
 124         }
 125         if (l==0) {
 126             fatal("tun_afterpoll: read()=0; device gone away?");
 127         }
 128         if (l>0) {
 129             st->buff->size=l;
 130             st->netlink_to_tunnel(&st->nl,st->buff);
 131             BUF_ASSERT_FREE(st->buff);
 132         }
 133     }
 134 }
 135
 136 static void tun_deliver_to_kernel(void *sst, struct buffer_if *buf)
 137 {
 138     struct tun *st=sst;
 139
 140     BUF_ASSERT_USED(buf);
 141     /* No error checking, because we'd just throw the packet away
 142        anyway if it didn't work. */
 143     write(st->fd,buf->start,buf->size);
 144     BUF_FREE(buf);
 145 }
 146
 147 static bool_t tun_set_route(void *sst, struct netlink_client *routes)
 148 {
 149     struct tun *st=sst;
 150     string_t network, mask, secnetaddr;
 151     struct subnet_list *nets;
 152     uint32_t i;
 153     int fd=-1;
 154
 155     if (routes->up == routes->kup) return False;
 156     if (st->route_type==TUN_CONFIG_IOCTL) {
 157         if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 158             fd=open(st->ip_path,O_RDWR);
 159             if (fd<0) {
 160                 fatal_perror("tun_set_route: can't open %s",st->ip_path);
 161             }
 162         } else {
 163             fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
 164             if (fd<0) {
 165                 fatal_perror("tun_set_route: socket()");
 166             }
 167         }
 168     }
 169     nets=routes->subnets;
 170     secnetaddr=ipaddr_to_string(st->nl.secnet_address);
 171     for (i=0; i<nets->entries; i++) {
 172         network=ipaddr_to_string(nets->list[i].prefix);
 173         mask=ipaddr_to_string(nets->list[i].mask);
 174         Message(M_INFO,"%s: %s route %s/%d %s kernel routing table\n",
 175                 st->nl.name,routes->up?"adding":"deleting",network,
 176                 nets->list[i].len,routes->up?"to":"from");
 177         switch (st->route_type) {
 178         case TUN_CONFIG_LINUX:
 179             sys_cmd(st->route_path,"route",routes->up?"add":"del",
 180                     "-net",network,"netmask",mask,
 181                     "gw",secnetaddr,(char *)0);
 182             break;
 183         case TUN_CONFIG_BSD:
 184             sys_cmd(st->route_path,"route",routes->up?"add":"del",
 185                     "-net",network,secnetaddr,mask,(char *)0);
 186             break;
 187         case TUN_CONFIG_SOLARIS25:
 188             sys_cmd(st->route_path,"route",routes->up?"add":"del",
 189                     network,secnetaddr,(char *)0);
 190             break;
 191         case TUN_CONFIG_IOCTL:
 192         {
 193           /* darwin rtentry has a different format, use /sbin/route instead */
 194 #if HAVE_NET_ROUTE_H && ! __APPLE__
 195             struct rtentry rt;
 196             struct sockaddr_in *sa;
 197             int action;
 198
 199             memset(&rt,0,sizeof(rt));
 200             sa=(struct sockaddr_in *)&rt.rt_dst;
 201             sa->sin_family=AF_INET;
 202             sa->sin_addr.s_addr=htonl(nets->list[i].prefix);
 203             sa=(struct sockaddr_in *)&rt.rt_genmask;
 204             sa->sin_family=AF_INET;
 205             sa->sin_addr.s_addr=htonl(nets->list[i].mask);
 206             sa=(struct sockaddr_in *)&rt.rt_gateway;
 207             sa->sin_family=AF_INET;
 208             sa->sin_addr.s_addr=htonl(st->nl.secnet_address);
 209             rt.rt_flags=RTF_UP|RTF_GATEWAY;
 210             action=routes->up?SIOCADDRT:SIOCDELRT;
 211             if (ioctl(fd,action,&rt)<0) {
 212                 fatal_perror("tun_set_route: ioctl()");
 213             }
 214 #else
 215             fatal("tun_set_route: ioctl method not supported");
 216 #endif
 217         }
 218         break;
 219         default:
 220             fatal("tun_set_route: unsupported route command type");
 221             break;
 222         }
 223         free(network); free(mask);
 224     }
 225     free(secnetaddr);
 226     if (st->route_type==TUN_CONFIG_IOCTL) {
 227         close(fd);
 228     }
 229     routes->kup=routes->up;
 230     return True;
 231 }
 232
 233 static void tun_phase_hook(void *sst, uint32_t newphase)
 234 {
 235     struct tun *st=sst;
 236     string_t hostaddr,secnetaddr;
 237     char mtu[6];
 238     struct netlink_client *r;
 239
 240     if (st->tun_flavour==TUN_FLAVOUR_BSD) {
 241         if (st->search_for_if) {
 242             string_t dname;
 243             int i;
 244
 245             dname=safe_malloc(strlen(st->device_path)+4,"tun_old_apply");
 246             st->interface_name=safe_malloc(8,"tun_phase_hook");
 247
 248             for (i=0; i<255; i++) {
 249                 sprintf(dname,"%s%d",st->device_path,i);
 250                 if ((st->fd=open(dname,O_RDWR))>0) {
 251                     sprintf(st->interface_name,"tun%d",i);
 252                     Message(M_INFO,"%s: allocated network interface %s "
 253                             "through %s\n",st->nl.name,st->interface_name,
 254                             dname);
 255                     break;
 256                 }
 257             }
 258             if (st->fd==-1) {
 259                 fatal("%s: unable to open any TUN device (%s...)",
 260                       st->nl.name,st->device_path);
 261             }
 262         } else {
 263             st->fd=open(st->device_path,O_RDWR);
 264             if (st->fd==-1) {
 265                 fatal_perror("%s: unable to open TUN device file %s",
 266                              st->nl.name,st->device_path);
 267             }
 268         }
 269     } else if (st->tun_flavour==TUN_FLAVOUR_LINUX) {
 270 #ifdef LINUX_TUN_SUPPORTED
 271         struct ifreq ifr;
 272
 273         /* New TUN interface: open the device, then do ioctl TUNSETIFF
 274            to set or find out the network interface name. */
 275         st->fd=open(st->device_path,O_RDWR);
 276         if (st->fd==-1) {
 277             fatal_perror("%s: can't open device file %s",st->nl.name,
 278                          st->device_path);
 279         }
 280         memset(&ifr,0,sizeof(ifr));
 281         ifr.ifr_flags = IFF_TUN | IFF_NO_PI; /* Just send/receive IP packets,
 282                                                 no extra headers */
 283         if (st->interface_name)
 284             strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 285         if (ioctl(st->fd,TUNSETIFF,&ifr)<0) {
 286             fatal_perror("%s: ioctl(TUNSETIFF)",st->nl.name);
 287         }
 288         if (!st->interface_name) {
 289             st->interface_name=safe_malloc(strlen(ifr.ifr_name)+1,"tun_apply");
 290             strcpy(st->interface_name,ifr.ifr_name);
 291             Message(M_INFO,"%s: allocated network interface %s\n",st->nl.name,
 292                     st->interface_name);
 293         }
 294 #else
 295         fatal("tun_phase_hook: TUN_FLAVOUR_LINUX unexpected");
 296 #endif /* LINUX_TUN_SUPPORTED */
 297     } else if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 298 #ifdef HAVE_TUN_STREAMS
 299         int tun_fd, if_fd, ppa=-1, ip_fd;
 300
 301         if ((ip_fd=open(st->ip_path, O_RDWR)) < 0) {
 302             fatal_perror("%s: can't open %s",st->nl.name,st->ip_path);
 303         }
 304         if ((tun_fd=open(st->device_path,O_RDWR)) < 0) {
 305             fatal_perror("%s: can't open %s",st->nl.name,st->device_path);
 306         }
 307         if ((ppa=ioctl(tun_fd,TUNNEWPPA,ppa)) < 0) {
 308             fatal_perror("%s: can't assign new interface");
 309         }
 310         if ((if_fd=open(st->device_path,O_RDWR)) < 0) {
 311             fatal_perror("%s: can't open %s (2)",st->nl.name,st->device_path);
 312         }
 313         if (ioctl(if_fd,I_PUSH,"ip") < 0) {
 314             fatal_perror("%s: can't push IP module",st->nl.name);
 315         }
 316         if (ioctl(if_fd,IF_UNITSEL,(char *)&ppa) < 0) {
 317             fatal_perror("%s: can't set ppa %d",st->nl.name,ppa);
 318         }
 319         if (ioctl(ip_fd, I_LINK, if_fd) < 0) {
 320             fatal_perror("%s: can't link TUN device to IP",st->nl.name);
 321         }
 322         st->interface_name=safe_malloc(10,"tun_apply");
 323         sprintf(st->interface_name,"tun%d",ppa);
 324         st->fd=tun_fd;
 325 #else
 326         fatal("tun_phase_hook: TUN_FLAVOUR_STREAMS unexpected");
 327 #endif /* HAVE_TUN_STREAMS */
 328     } else {
 329         fatal("tun_phase_hook: unknown flavour of TUN");
 330     }
 331     /* All the networks we'll be using have been registered. Invoke ifconfig
 332        to set the TUN device's address, and route to add routes to all
 333        our networks. */
 334
 335     hostaddr=ipaddr_to_string(st->local_address);
 336     secnetaddr=ipaddr_to_string(st->nl.secnet_address);
 337     snprintf(mtu,6,"%d",st->nl.mtu);
 338     mtu[5]=0;
 339
 340     switch (st->ifconfig_type) {
 341     case TUN_CONFIG_LINUX:
 342         sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
 343                 hostaddr,"netmask","255.255.255.255","-broadcast",
 344                 "-multicast",
 345                 "pointopoint",secnetaddr,"mtu",mtu,"up",(char *)0);
 346         break;
 347     case TUN_CONFIG_BSD:
 348         sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
 349                 hostaddr,"netmask","255.255.255.255",
 350                 secnetaddr,"mtu",mtu,"up",(char *)0);
 351         break;
 352     case TUN_CONFIG_SOLARIS25:
 353         sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
 354                 hostaddr,secnetaddr,"mtu",mtu,"up",(char *)0);
 355         break;
 356     case TUN_CONFIG_IOCTL:
 357 #if HAVE_NET_IF_H && ! __APPLE__
 358     {
 359         int fd;
 360         struct ifreq ifr;
 361         struct sockaddr_in *sa;
 362         fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
 363
 364         /* Interface address */
 365         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 366         sa=(struct sockaddr_in *)&ifr.ifr_addr;
 367         memset(sa,0,sizeof(*sa));
 368         sa->sin_family=AF_INET;
 369         sa->sin_addr.s_addr=htonl(st->local_address);
 370         if (ioctl(fd,SIOCSIFADDR, &ifr)!=0) {
 371             fatal_perror("tun_apply: SIOCSIFADDR");
 372         }
 373 #ifdef SIOCSIFNETMASK
 374         /* Netmask */
 375         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 376         sa=(struct sockaddr_in *)&ifr.ifr_netmask;
 377         memset(sa,0,sizeof(*sa));
 378         sa->sin_family=AF_INET;
 379         sa->sin_addr.s_addr=htonl(0xffffffff);
 380         if (ioctl(fd,SIOCSIFNETMASK, &ifr)!=0) {
 381             fatal_perror("tun_apply: SIOCSIFNETMASK");
 382         }
 383 #endif
 384         /* Destination address (point-to-point) */
 385         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 386         sa=(struct sockaddr_in *)&ifr.ifr_dstaddr;
 387         memset(sa,0,sizeof(*sa));
 388         sa->sin_family=AF_INET;
 389         sa->sin_addr.s_addr=htonl(st->nl.secnet_address);
 390         if (ioctl(fd,SIOCSIFDSTADDR, &ifr)!=0) {
 391             fatal_perror("tun_apply: SIOCSIFDSTADDR");
 392         }
 393         /* MTU */
 394         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 395         ifr.ifr_mtu=st->nl.mtu;
 396         if (ioctl(fd,SIOCSIFMTU, &ifr)!=0) {
 397             fatal_perror("tun_apply: SIOCSIFMTU");
 398         }
 399         /* Flags */
 400         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 401         ifr.ifr_flags=IFF_UP|IFF_POINTOPOINT|IFF_RUNNING|IFF_NOARP;
 402         if (ioctl(fd,SIOCSIFFLAGS, &ifr)!=0) {
 403             fatal_perror("tun_apply: SIOCSIFFLAGS");
 404         }
 405
 406         close(fd);
 407     }
 408 #else
 409     fatal("tun_apply: ifconfig by ioctl() not supported");
 410 #endif /* HAVE_NET_IF_H */
 411     break;
 412     default:
 413         fatal("tun_apply: unsupported ifconfig method");
 414         break;
 415     }
 416
 417     for (r=st->nl.clients; r; r=r->next) {
 418         tun_set_route(st,r);
 419     }
 420
 421     /* Register for poll() */
 422     register_for_poll(st, tun_beforepoll, tun_afterpoll, 1, st->nl.name);
 423 }
 424
 425 static list_t *tun_create(closure_t *self, struct cloc loc, dict_t *context,
 426                           list_t *args,uint32_t default_flavour)
 427 {
 428     struct tun *st;
 429     item_t *item;
 430     dict_t *dict;
 431     string_t flavour,type;
 432
 433     st=safe_malloc(sizeof(*st),"tun_apply");
 434
 435     /* First parameter must be a dict */
 436     item=list_elem(args,0);
 437     if (!item || item->type!=t_dict)
 438         cfgfatal(loc,"tun","parameter must be a dictionary\n");
 439
 440     dict=item->data.dict;
 441
 442     st->netlink_to_tunnel=
 443         netlink_init(&st->nl,st,loc,dict,
 444                      "netlink-tun",tun_set_route,tun_deliver_to_kernel);
 445
 446     flavour=dict_read_string(dict,"flavour",False,"tun-netlink",loc);
 447     if (flavour)
 448         st->tun_flavour=string_to_word(flavour,loc,flavours,"tun-flavour");
 449     else
 450         st->tun_flavour=default_flavour;
 451
 452     st->device_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
 453     st->ip_path=dict_read_string(dict,"ip-path",False,"tun-netlink",loc);
 454     st->interface_name=dict_read_string(dict,"interface",False,
 455                                         "tun-netlink",loc);
 456     st->search_for_if=dict_read_bool(dict,"interface-search",False,
 457                                      "tun-netlink",loc,st->device_path==NULL);
 458
 459     type=dict_read_string(dict,"ifconfig-type",False,"tun-netlink",loc);
 460     if (type) st->ifconfig_type=string_to_word(type,loc,config_types,
 461                                                "ifconfig-type");
 462     else st->ifconfig_type=TUN_CONFIG_GUESS;
 463     st->ifconfig_path=dict_read_string(dict,"ifconfig-path",False,
 464                                        "tun-netlink",loc);
 465
 466     type=dict_read_string(dict,"route-type",False,"tun-netlink",loc);
 467     if (type) st->route_type=string_to_word(type,loc,config_types,
 468                                             "route-type");
 469     else st->route_type=TUN_CONFIG_GUESS;
 470     st->route_path=dict_read_string(dict,"route-path",False,"tun-netlink",loc);
 471
 472     st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"tun-netlink",loc);
 473     st->local_address=string_item_to_ipaddr(
 474         dict_find_item(dict,"local-address", True, "netlink", loc),"netlink");
 475
 476     if (st->tun_flavour==TUN_FLAVOUR_GUESS) {
 477         /* If we haven't been told what type of TUN we're using, take
 478            a guess based on the system details. */
 479         struct utsname u;
 480         if (uname(&u)<0) {
 481             fatal_perror("tun_create: uname");
 482         }
 483         if (strcmp(u.sysname,"Linux")==0) {
 484             if (u.release[0]=='2' && u.release[1]=='.' && u.release[3]=='.') {
 485                 if (u.release[2]=='2') st->tun_flavour=TUN_FLAVOUR_BSD;
 486                 else if (u.release[2]=='4') st->tun_flavour=TUN_FLAVOUR_LINUX;
 487             }
 488         } else if (strcmp(u.sysname,"SunOS")==0) {
 489             st->tun_flavour=TUN_FLAVOUR_STREAMS;
 490         } else if (strcmp(u.sysname,"FreeBSD")==0
 491                    || strcmp(u.sysname,"Darwin")==0) {
 492             st->tun_flavour=TUN_FLAVOUR_BSD;
 493         }
 494     }
 495     if (st->tun_flavour==TUN_FLAVOUR_GUESS) {
 496         cfgfatal(loc,"tun","cannot guess which type of TUN is in use; "
 497                  "specify the flavour explicitly\n");
 498     }
 499
 500     if (st->ifconfig_type==TUN_CONFIG_GUESS) {
 501         switch (st->tun_flavour) {
 502         case TUN_FLAVOUR_LINUX:
 503             st->ifconfig_type=TUN_CONFIG_IOCTL;
 504             break;
 505         case TUN_FLAVOUR_BSD:
 506 #if __linux__
 507             /* XXX on Linux we still want TUN_CONFIG_IOCTL.  Perhaps we can
 508                use this on BSD too. */
 509             st->ifconfig_type=TUN_CONFIG_IOCTL;
 510 #else
 511             st->ifconfig_type=TUN_CONFIG_BSD;
 512 #endif
 513             break;
 514         case TUN_FLAVOUR_STREAMS:
 515             st->ifconfig_type=TUN_CONFIG_BSD;
 516             break;
 517         }
 518     }
 519     if (st->route_type==TUN_CONFIG_GUESS)
 520         st->route_type=st->ifconfig_type;
 521
 522     if (st->ifconfig_type==TUN_CONFIG_GUESS) {
 523         cfgfatal(loc,"tun","cannot guess which ifconfig method to use\n");
 524     }
 525     if (st->route_type==TUN_CONFIG_GUESS) {
 526         cfgfatal(loc,"tun","cannot guess which route method to use\n");
 527     }
 528
 529     if (st->ifconfig_type==TUN_CONFIG_IOCTL && st->ifconfig_path) {
 530         cfgfatal(loc,"tun","ifconfig-type \"ioctl\" is incompatible with "
 531                  "ifconfig-path\n");
 532     }
 533     if (st->route_type==TUN_CONFIG_IOCTL && st->route_path) {
 534         cfgfatal(loc,"tun","route-type \"ioctl\" is incompatible with "
 535                  "route-path\n");
 536     }
 537
 538     Message(M_DEBUG_CONFIG,"%s: tun flavour %s\n",st->nl.name,
 539             tun_flavour_str(st->tun_flavour));
 540     switch (st->tun_flavour) {
 541     case TUN_FLAVOUR_BSD:
 542         if (!st->device_path) st->device_path="/dev/tun";
 543         break;
 544     case TUN_FLAVOUR_LINUX:
 545         if (!st->device_path) st->device_path="/dev/net/tun";
 546         break;
 547     case TUN_FLAVOUR_STREAMS:
 548         if (!st->device_path) st->device_path="/dev/tun";
 549         if (st->interface_name) cfgfatal(loc,"tun","interface name cannot "
 550                                          "be specified with STREAMS TUN\n");
 551         break;
 552     }
 553
 554     if (!st->ip_path) st->ip_path="/dev/ip";
 555     if (!st->ifconfig_path) st->ifconfig_path="ifconfig";
 556     if (!st->route_path) st->route_path="route";
 557
 558 #ifndef HAVE_TUN_STREAMS
 559     if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 560         cfgfatal(loc,"tun","TUN flavour STREAMS unsupported in this build "
 561                  "of secnet\n");
 562     }
 563 #endif
 564 #ifndef LINUX_TUN_SUPPORTED
 565     if (st->tun_flavour==TUN_FLAVOUR_LINUX) {
 566         cfgfatal(loc,"tun","TUN flavour LINUX unsupported in this build "
 567                  "of secnet\n");
 568     }
 569 #endif
 570
 571     /* Old TUN interface: the network interface name depends on which
 572        /dev/tunX file we open. If 'interface-search' is set to true, treat
 573        'device' as the prefix and try numbers from 0--255. If it's set
 574        to false, treat 'device' as the whole name, and require than an
 575        appropriate interface name be specified. */
 576     if (st->tun_flavour==TUN_FLAVOUR_BSD) {
 577         if (st->search_for_if && st->interface_name) {
 578             cfgfatal(loc,"tun","you may not specify an interface name "
 579                      "in interface-search mode\n");
 580         }
 581         if (!st->search_for_if && !st->interface_name) {
 582             cfgfatal(loc,"tun","you must specify an interface name "
 583                      "when you explicitly specify a TUN device file\n");
 584         }
 585     }
 586
 587     add_hook(PHASE_GETRESOURCES,tun_phase_hook,st);
 588
 589     return new_closure(&st->nl.cl);
 590 }
 591
 592 static list_t *tun_apply(closure_t *self, struct cloc loc, dict_t *context,
 593                          list_t *args)
 594 {
 595     return tun_create(self,loc,context,args,TUN_FLAVOUR_GUESS);
 596 }
 597
 598 static list_t *tun_bsd_apply(closure_t *self, struct cloc loc, dict_t *context,
 599                              list_t *args)
 600 {
 601     Message(M_WARNING,"(%s,%d): obsolete use of tun-old; replace with tun "
 602             "and specify flavour \"bsd\".\n",loc.file,loc.line);
 603     return tun_create(self,loc,context,args,TUN_FLAVOUR_BSD);
 604 }
 605
 606 void tun_module(dict_t *dict)
 607 {
 608     add_closure(dict,"tun",tun_apply);
 609     add_closure(dict,"tun-old",tun_bsd_apply);
 610 }