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 <errno.h>
   7 #include <unistd.h>
   8 #include <fcntl.h>
   9 #include <sys/ioctl.h>
  10 #include <sys/utsname.h>
  11 #include <sys/socket.h>
  12
  13 #ifdef HAVE_NET_IF_H
  14 #include <net/if.h>
  15 #ifdef HAVE_LINUX_IF_H
  16 #include <linux/if_tun.h>
  17 #define LINUX_TUN_SUPPORTED
  18 #endif
  19 #endif
  20
  21 #ifdef HAVE_NET_ROUTE_H
  22 #include <net/route.h>
  23 #endif
  24
  25 #if defined(HAVE_STROPTS_H) && defined(HAVE_SYS_SOCKIO_H) && \
  26 defined(HAVE_NET_IF_TUN_H)
  27 #define HAVE_TUN_STREAMS
  28 #endif
  29
  30 #ifdef HAVE_TUN_STREAMS
  31 #include <stropts.h>
  32 #include <sys/sockio.h>
  33 #include <net/if_tun.h>
  34 #endif
  35
  36 #define TUN_FLAVOUR_GUESS   0
  37 #define TUN_FLAVOUR_BSD     1
  38 #define TUN_FLAVOUR_LINUX   2
  39 #define TUN_FLAVOUR_STREAMS 3
  40
  41 static struct flagstr flavours[]={
  42     {"guess", TUN_FLAVOUR_GUESS},
  43     {"bsd", TUN_FLAVOUR_BSD},
  44     {"BSD", TUN_FLAVOUR_BSD},
  45     {"linux", TUN_FLAVOUR_LINUX},
  46     {"streams", TUN_FLAVOUR_STREAMS},
  47     {"STREAMS", TUN_FLAVOUR_STREAMS},
  48     {NULL, 0}
  49 };
  50
  51 #define TUN_CONFIG_GUESS      0
  52 #define TUN_CONFIG_IOCTL      1
  53 #define TUN_CONFIG_BSD        2
  54 #define TUN_CONFIG_LINUX      3
  55 #define TUN_CONFIG_SOLARIS25  4
  56
  57 static struct flagstr config_types[]={
  58     {"guess", TUN_CONFIG_GUESS},
  59     {"ioctl", TUN_CONFIG_IOCTL},
  60     {"bsd", TUN_CONFIG_BSD},
  61     {"BSD", TUN_CONFIG_BSD},
  62     {"linux", TUN_CONFIG_LINUX},
  63     {"solaris-2.5", TUN_CONFIG_SOLARIS25},
  64     {NULL, 0}
  65 };
  66
  67 /* Connection to the kernel through the universal TUN/TAP driver */
  68
  69 struct tun {
  70     struct netlink nl;
  71     int fd;
  72     cstring_t device_path;
  73     cstring_t ip_path;
  74     string_t interface_name;
  75     cstring_t ifconfig_path;
  76     uint32_t ifconfig_type;
  77     cstring_t route_path;
  78     uint32_t route_type;
  79     uint32_t tun_flavour;
  80     bool_t search_for_if; /* Applies to tun-BSD only */
  81     struct buffer_if *buff; /* We receive packets into here
  82                                and send them to the netlink code. */
  83     netlink_deliver_fn *netlink_to_tunnel;
  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)
  99 {
 100     struct tun *st=sst;
 101     *nfds_io=1;
 102     fds[0].fd=st->fd;
 103     fds[0].events=POLLIN;
 104     return 0;
 105 }
 106
 107 static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds)
 108 {
 109     struct tun *st=sst;
 110     int l;
 111
 112     if (nfds==0) return;
 113     if (fds[0].revents&POLLERR) {
 114         printf("tun_afterpoll: hup!\n");
 115     }
 116     if (fds[0].revents&POLLIN) {
 117         BUF_ALLOC(st->buff,"tun_afterpoll");
 118         buffer_init(st->buff,calculate_max_start_pad());
 119         l=read(st->fd,st->buff->start,st->buff->len-calculate_max_start_pad());
 120         if (l<0) {
 121             fatal_perror("tun_afterpoll: read()");
 122         }
 123         if (l==0) {
 124             fatal("tun_afterpoll: read()=0; device gone away?");
 125         }
 126         if (l>0) {
 127             st->buff->size=l;
 128             st->netlink_to_tunnel(&st->nl,st->buff);
 129             BUF_ASSERT_FREE(st->buff);
 130         }
 131     }
 132 }
 133
 134 static void tun_deliver_to_kernel(void *sst, struct buffer_if *buf)
 135 {
 136     struct tun *st=sst;
 137     ssize_t rc;
 138
 139     BUF_ASSERT_USED(buf);
 140
 141     /* Log errors, so we can tell what's going on, but only once a
 142        minute, so we don't flood the logs.  Short writes count as
 143        errors. */
 144     rc = write(st->fd,buf->start,buf->size);
 145     if(rc != buf->size) {
 146         static struct timeval last_report;
 147         if(tv_now_global.tv_sec >= last_report.tv_sec + 60) {
 148             if(rc < 0)
 149                 Message(M_WARNING,
 150                         "failed to deliver packet to tun device: %s\n",
 151                         strerror(errno));
 152             else
 153                 Message(M_WARNING,
 154                         "truncated packet delivered to tun device\n");
 155             last_report = tv_now_global;
 156         }
 157     }
 158     BUF_FREE(buf);
 159 }
 160
 161 static bool_t tun_set_route(void *sst, struct netlink_client *routes)
 162 {
 163     struct tun *st=sst;
 164     string_t network, mask, secnetaddr;
 165     struct subnet_list *nets;
 166     int32_t i;
 167     int fd=-1;
 168     bool_t up;
 169
 170     if (routes->options & OPT_SOFTROUTE)
 171         up = routes->up;
 172     else
 173         up = routes->link_quality > LINK_QUALITY_UNUSED;
 174
 175     if (up == routes->kup) return False;
 176     if (st->route_type==TUN_CONFIG_IOCTL) {
 177         if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 178             fd=open(st->ip_path,O_RDWR);
 179             if (fd<0) {
 180                 fatal_perror("tun_set_route: can't open %s",st->ip_path);
 181             }
 182         } else {
 183             fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
 184             if (fd<0) {
 185                 fatal_perror("tun_set_route: socket()");
 186             }
 187         }
 188     }
 189     nets=routes->subnets;
 190     secnetaddr=ipaddr_to_string(st->nl.secnet_address);
 191     for (i=0; i<nets->entries; i++) {
 192         network=ipaddr_to_string(nets->list[i].prefix);
 193         mask=ipaddr_to_string(nets->list[i].mask);
 194         Message(M_INFO,"%s: %s route %s/%d %s kernel routing table\n",
 195                 st->nl.name,up?"adding":"deleting",network,
 196                 nets->list[i].len,up?"to":"from");
 197         switch (st->route_type) {
 198         case TUN_CONFIG_LINUX:
 199             sys_cmd(st->route_path,"route",up?"add":"del",
 200                     "-net",network,"netmask",mask,
 201                     "gw",secnetaddr,(char *)0);
 202             break;
 203         case TUN_CONFIG_BSD:
 204             sys_cmd(st->route_path,"route",up?"add":"del",
 205                     "-net",network,secnetaddr,mask,(char *)0);
 206             break;
 207         case TUN_CONFIG_SOLARIS25:
 208             sys_cmd(st->route_path,"route",up?"add":"del",
 209                     network,secnetaddr,(char *)0);
 210             break;
 211         case TUN_CONFIG_IOCTL:
 212         {
 213           /* darwin rtentry has a different format, use /sbin/route instead */
 214 #if HAVE_NET_ROUTE_H && ! __APPLE__
 215             struct rtentry rt;
 216             struct sockaddr_in *sa;
 217             int action;
 218
 219             FILLZERO(rt);
 220             sa=(struct sockaddr_in *)&rt.rt_dst;
 221             sa->sin_family=AF_INET;
 222             sa->sin_addr.s_addr=htonl(nets->list[i].prefix);
 223             sa=(struct sockaddr_in *)&rt.rt_genmask;
 224             sa->sin_family=AF_INET;
 225             sa->sin_addr.s_addr=htonl(nets->list[i].mask);
 226             sa=(struct sockaddr_in *)&rt.rt_gateway;
 227             sa->sin_family=AF_INET;
 228             sa->sin_addr.s_addr=htonl(st->nl.secnet_address);
 229             rt.rt_flags=RTF_UP|RTF_GATEWAY;
 230             action=up?SIOCADDRT:SIOCDELRT;
 231             if (ioctl(fd,action,&rt)<0) {
 232                 fatal_perror("tun_set_route: ioctl()");
 233             }
 234 #else
 235             fatal("tun_set_route: ioctl method not supported");
 236 #endif
 237         }
 238         break;
 239         default:
 240             fatal("tun_set_route: unsupported route command type");
 241             break;
 242         }
 243         free(network); free(mask);
 244     }
 245     free(secnetaddr);
 246     if (st->route_type==TUN_CONFIG_IOCTL) {
 247         close(fd);
 248     }
 249     routes->kup=up;
 250     return True;
 251 }
 252
 253 static void tun_phase_hook(void *sst, uint32_t newphase)
 254 {
 255     struct tun *st=sst;
 256     string_t hostaddr,secnetaddr;
 257     char mtu[6];
 258     struct netlink_client *r;
 259
 260     if (st->tun_flavour==TUN_FLAVOUR_BSD) {
 261         if (st->search_for_if) {
 262             string_t dname;
 263             int i;
 264
 265             dname=safe_malloc(strlen(st->device_path)+4,"tun_old_apply");
 266             st->interface_name=safe_malloc(8,"tun_phase_hook");
 267
 268             for (i=0; i<255; i++) {
 269                 sprintf(dname,"%s%d",st->device_path,i);
 270                 if ((st->fd=open(dname,O_RDWR))>0) {
 271                     sprintf(st->interface_name,"tun%d",i);
 272                     Message(M_INFO,"%s: allocated network interface %s "
 273                             "through %s\n",st->nl.name,st->interface_name,
 274                             dname);
 275                     break;
 276                 }
 277             }
 278             if (st->fd==-1) {
 279                 fatal("%s: unable to open any TUN device (%s...)",
 280                       st->nl.name,st->device_path);
 281             }
 282         } else {
 283             st->fd=open(st->device_path,O_RDWR);
 284             if (st->fd==-1) {
 285                 fatal_perror("%s: unable to open TUN device file %s",
 286                              st->nl.name,st->device_path);
 287             }
 288         }
 289     } else if (st->tun_flavour==TUN_FLAVOUR_LINUX) {
 290 #ifdef LINUX_TUN_SUPPORTED
 291         struct ifreq ifr;
 292
 293         /* New TUN interface: open the device, then do ioctl TUNSETIFF
 294            to set or find out the network interface name. */
 295         st->fd=open(st->device_path,O_RDWR);
 296         if (st->fd==-1) {
 297             fatal_perror("%s: can't open device file %s",st->nl.name,
 298                          st->device_path);
 299         }
 300         FILLZERO(ifr);
 301         ifr.ifr_flags = IFF_TUN | IFF_NO_PI; /* Just send/receive IP packets,
 302                                                 no extra headers */
 303         if (st->interface_name)
 304             strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 305         if (ioctl(st->fd,TUNSETIFF,&ifr)<0) {
 306             fatal_perror("%s: ioctl(TUNSETIFF)",st->nl.name);
 307         }
 308         if (!st->interface_name) {
 309             st->interface_name=safe_malloc(strlen(ifr.ifr_name)+1,"tun_apply");
 310             strcpy(st->interface_name,ifr.ifr_name);
 311             Message(M_INFO,"%s: allocated network interface %s\n",st->nl.name,
 312                     st->interface_name);
 313         }
 314 #else
 315         fatal("tun_phase_hook: TUN_FLAVOUR_LINUX unexpected");
 316 #endif /* LINUX_TUN_SUPPORTED */
 317     } else if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 318 #ifdef HAVE_TUN_STREAMS
 319         int tun_fd, if_fd, ppa=-1, ip_fd;
 320
 321         if ((ip_fd=open(st->ip_path, O_RDWR)) < 0) {
 322             fatal_perror("%s: can't open %s",st->nl.name,st->ip_path);
 323         }
 324         if ((tun_fd=open(st->device_path,O_RDWR)) < 0) {
 325             fatal_perror("%s: can't open %s",st->nl.name,st->device_path);
 326         }
 327         if ((ppa=ioctl(tun_fd,TUNNEWPPA,ppa)) < 0) {
 328             fatal_perror("%s: can't assign new interface");
 329         }
 330         if ((if_fd=open(st->device_path,O_RDWR)) < 0) {
 331             fatal_perror("%s: can't open %s (2)",st->nl.name,st->device_path);
 332         }
 333         if (ioctl(if_fd,I_PUSH,"ip") < 0) {
 334             fatal_perror("%s: can't push IP module",st->nl.name);
 335         }
 336         if (ioctl(if_fd,IF_UNITSEL,(char *)&ppa) < 0) {
 337             fatal_perror("%s: can't set ppa %d",st->nl.name,ppa);
 338         }
 339         if (ioctl(ip_fd, I_LINK, if_fd) < 0) {
 340             fatal_perror("%s: can't link TUN device to IP",st->nl.name);
 341         }
 342         st->interface_name=safe_malloc(10,"tun_apply");
 343         sprintf(st->interface_name,"tun%d",ppa);
 344         st->fd=tun_fd;
 345 #else
 346         fatal("tun_phase_hook: TUN_FLAVOUR_STREAMS unexpected");
 347 #endif /* HAVE_TUN_STREAMS */
 348     } else {
 349         fatal("tun_phase_hook: unknown flavour of TUN");
 350     }
 351     /* All the networks we'll be using have been registered. Invoke ifconfig
 352        to set the TUN device's address, and route to add routes to all
 353        our networks. */
 354
 355     hostaddr=ipaddr_to_string(st->nl.local_address);
 356     secnetaddr=ipaddr_to_string(st->nl.secnet_address);
 357     snprintf(mtu,sizeof(mtu),"%d",st->nl.mtu);
 358     mtu[5]=0;
 359
 360     switch (st->ifconfig_type) {
 361     case TUN_CONFIG_LINUX:
 362         sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
 363                 hostaddr,"netmask","255.255.255.255","-broadcast",
 364                 "-multicast",
 365                 "pointopoint",secnetaddr,"mtu",mtu,"up",(char *)0);
 366         break;
 367     case TUN_CONFIG_BSD:
 368         sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
 369                 hostaddr,"netmask","255.255.255.255",
 370                 secnetaddr,"mtu",mtu,"up",(char *)0);
 371         break;
 372     case TUN_CONFIG_SOLARIS25:
 373         sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
 374                 hostaddr,secnetaddr,"mtu",mtu,"up",(char *)0);
 375         break;
 376     case TUN_CONFIG_IOCTL:
 377 #if HAVE_NET_IF_H && ! __APPLE__
 378     {
 379         int fd;
 380         struct ifreq ifr;
 381         struct sockaddr_in *sa;
 382         fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
 383
 384         /* Interface address */
 385         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 386         sa=(struct sockaddr_in *)&ifr.ifr_addr;
 387         FILLZERO(*sa);
 388         sa->sin_family=AF_INET;
 389         sa->sin_addr.s_addr=htonl(st->nl.local_address);
 390         if (ioctl(fd,SIOCSIFADDR, &ifr)!=0) {
 391             fatal_perror("tun_apply: SIOCSIFADDR");
 392         }
 393 #ifdef SIOCSIFNETMASK
 394         /* Netmask */
 395         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 396         sa=(struct sockaddr_in *)&ifr.ifr_netmask;
 397         FILLZERO(*sa);
 398         sa->sin_family=AF_INET;
 399         sa->sin_addr.s_addr=htonl(0xffffffff);
 400         if (ioctl(fd,SIOCSIFNETMASK, &ifr)!=0) {
 401             fatal_perror("tun_apply: SIOCSIFNETMASK");
 402         }
 403 #endif
 404         /* Destination address (point-to-point) */
 405         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 406         sa=(struct sockaddr_in *)&ifr.ifr_dstaddr;
 407         FILLZERO(*sa);
 408         sa->sin_family=AF_INET;
 409         sa->sin_addr.s_addr=htonl(st->nl.secnet_address);
 410         if (ioctl(fd,SIOCSIFDSTADDR, &ifr)!=0) {
 411             fatal_perror("tun_apply: SIOCSIFDSTADDR");
 412         }
 413         /* MTU */
 414         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 415         ifr.ifr_mtu=st->nl.mtu;
 416         if (ioctl(fd,SIOCSIFMTU, &ifr)!=0) {
 417             fatal_perror("tun_apply: SIOCSIFMTU");
 418         }
 419         /* Flags */
 420         strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
 421         ifr.ifr_flags=IFF_UP|IFF_POINTOPOINT|IFF_RUNNING|IFF_NOARP;
 422         if (ioctl(fd,SIOCSIFFLAGS, &ifr)!=0) {
 423             fatal_perror("tun_apply: SIOCSIFFLAGS");
 424         }
 425
 426         close(fd);
 427     }
 428 #else
 429     fatal("tun_apply: ifconfig by ioctl() not supported");
 430 #endif /* HAVE_NET_IF_H */
 431     break;
 432     default:
 433         fatal("tun_apply: unsupported ifconfig method");
 434         break;
 435     }
 436
 437     for (r=st->nl.clients; r; r=r->next) {
 438         tun_set_route(st,r);
 439     }
 440
 441     /* Register for poll() */
 442     register_for_poll(st, tun_beforepoll, tun_afterpoll, 1, st->nl.name);
 443 }
 444
 445 static list_t *tun_create(closure_t *self, struct cloc loc, dict_t *context,
 446                           list_t *args,uint32_t default_flavour)
 447 {
 448     struct tun *st;
 449     item_t *item;
 450     dict_t *dict;
 451     string_t flavour,type;
 452
 453     st=safe_malloc(sizeof(*st),"tun_apply");
 454
 455     /* First parameter must be a dict */
 456     item=list_elem(args,0);
 457     if (!item || item->type!=t_dict)
 458         cfgfatal(loc,"tun","parameter must be a dictionary\n");
 459
 460     dict=item->data.dict;
 461
 462     st->netlink_to_tunnel=
 463         netlink_init(&st->nl,st,loc,dict,
 464                      "netlink-tun",tun_set_route,tun_deliver_to_kernel);
 465
 466     flavour=dict_read_string(dict,"flavour",False,"tun-netlink",loc);
 467     if (flavour)
 468         st->tun_flavour=string_to_word(flavour,loc,flavours,"tun-flavour");
 469     else
 470         st->tun_flavour=default_flavour;
 471
 472     st->device_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
 473     st->ip_path=dict_read_string(dict,"ip-path",False,"tun-netlink",loc);
 474     st->interface_name=dict_read_string(dict,"interface",False,
 475                                         "tun-netlink",loc);
 476     st->search_for_if=dict_read_bool(dict,"interface-search",False,
 477                                      "tun-netlink",loc,st->device_path==NULL);
 478
 479     type=dict_read_string(dict,"ifconfig-type",False,"tun-netlink",loc);
 480     if (type) st->ifconfig_type=string_to_word(type,loc,config_types,
 481                                                "ifconfig-type");
 482     else st->ifconfig_type=TUN_CONFIG_GUESS;
 483     st->ifconfig_path=dict_read_string(dict,"ifconfig-path",False,
 484                                        "tun-netlink",loc);
 485
 486     type=dict_read_string(dict,"route-type",False,"tun-netlink",loc);
 487     if (type) st->route_type=string_to_word(type,loc,config_types,
 488                                             "route-type");
 489     else st->route_type=TUN_CONFIG_GUESS;
 490     st->route_path=dict_read_string(dict,"route-path",False,"tun-netlink",loc);
 491
 492     st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"tun-netlink",loc);
 493
 494     if (st->tun_flavour==TUN_FLAVOUR_GUESS) {
 495         /* If we haven't been told what type of TUN we're using, take
 496            a guess based on the system details. */
 497         struct utsname u;
 498         if (uname(&u)<0) {
 499             fatal_perror("tun_create: uname");
 500         }
 501         if (strcmp(u.sysname,"Linux")==0) {
 502             st->tun_flavour=TUN_FLAVOUR_LINUX;
 503         } else if (strcmp(u.sysname,"SunOS")==0) {
 504             st->tun_flavour=TUN_FLAVOUR_STREAMS;
 505         } else if (strcmp(u.sysname,"FreeBSD")==0
 506                    || strcmp(u.sysname,"Darwin")==0) {
 507             st->tun_flavour=TUN_FLAVOUR_BSD;
 508         }
 509     }
 510     if (st->tun_flavour==TUN_FLAVOUR_GUESS) {
 511         cfgfatal(loc,"tun","cannot guess which type of TUN is in use; "
 512                  "specify the flavour explicitly\n");
 513     }
 514
 515     if (st->ifconfig_type==TUN_CONFIG_GUESS) {
 516         switch (st->tun_flavour) {
 517         case TUN_FLAVOUR_LINUX:
 518             st->ifconfig_type=TUN_CONFIG_IOCTL;
 519             break;
 520         case TUN_FLAVOUR_BSD:
 521 #if __linux__
 522             /* XXX on Linux we still want TUN_CONFIG_IOCTL.  Perhaps we can
 523                use this on BSD too. */
 524             st->ifconfig_type=TUN_CONFIG_IOCTL;
 525 #else
 526             st->ifconfig_type=TUN_CONFIG_BSD;
 527 #endif
 528             break;
 529         case TUN_FLAVOUR_STREAMS:
 530             st->ifconfig_type=TUN_CONFIG_BSD;
 531             break;
 532         }
 533     }
 534     if (st->route_type==TUN_CONFIG_GUESS)
 535         st->route_type=st->ifconfig_type;
 536
 537     if (st->ifconfig_type==TUN_CONFIG_GUESS) {
 538         cfgfatal(loc,"tun","cannot guess which ifconfig method to use\n");
 539     }
 540     if (st->route_type==TUN_CONFIG_GUESS) {
 541         cfgfatal(loc,"tun","cannot guess which route method to use\n");
 542     }
 543
 544     if (st->ifconfig_type==TUN_CONFIG_IOCTL && st->ifconfig_path) {
 545         cfgfatal(loc,"tun","ifconfig-type \"ioctl\" is incompatible with "
 546                  "ifconfig-path\n");
 547     }
 548     if (st->route_type==TUN_CONFIG_IOCTL && st->route_path) {
 549         cfgfatal(loc,"tun","route-type \"ioctl\" is incompatible with "
 550                  "route-path\n");
 551     }
 552
 553     Message(M_DEBUG_CONFIG,"%s: tun flavour %s\n",st->nl.name,
 554             tun_flavour_str(st->tun_flavour));
 555     switch (st->tun_flavour) {
 556     case TUN_FLAVOUR_BSD:
 557         if (!st->device_path) st->device_path="/dev/tun";
 558         break;
 559     case TUN_FLAVOUR_LINUX:
 560         if (!st->device_path) st->device_path="/dev/net/tun";
 561         break;
 562     case TUN_FLAVOUR_STREAMS:
 563         if (!st->device_path) st->device_path="/dev/tun";
 564         if (st->interface_name) cfgfatal(loc,"tun","interface name cannot "
 565                                          "be specified with STREAMS TUN\n");
 566         break;
 567     }
 568
 569     if (!st->ip_path) st->ip_path="/dev/ip";
 570     if (!st->ifconfig_path) st->ifconfig_path="ifconfig";
 571     if (!st->route_path) st->route_path="route";
 572
 573 #ifndef HAVE_TUN_STREAMS
 574     if (st->tun_flavour==TUN_FLAVOUR_STREAMS) {
 575         cfgfatal(loc,"tun","TUN flavour STREAMS unsupported in this build "
 576                  "of secnet\n");
 577     }
 578 #endif
 579 #ifndef LINUX_TUN_SUPPORTED
 580     if (st->tun_flavour==TUN_FLAVOUR_LINUX) {
 581         cfgfatal(loc,"tun","TUN flavour LINUX unsupported in this build "
 582                  "of secnet\n");
 583     }
 584 #endif
 585
 586     /* Old TUN interface: the network interface name depends on which
 587        /dev/tunX file we open. If 'interface-search' is set to true, treat
 588        'device' as the prefix and try numbers from 0--255. If it's set
 589        to false, treat 'device' as the whole name, and require than an
 590        appropriate interface name be specified. */
 591     if (st->tun_flavour==TUN_FLAVOUR_BSD) {
 592         if (st->search_for_if && st->interface_name) {
 593             cfgfatal(loc,"tun","you may not specify an interface name "
 594                      "in interface-search mode\n");
 595         }
 596         if (!st->search_for_if && !st->interface_name) {
 597             cfgfatal(loc,"tun","you must specify an interface name "
 598                      "when you explicitly specify a TUN device file\n");
 599         }
 600     }
 601
 602     add_hook(PHASE_GETRESOURCES,tun_phase_hook,st);
 603
 604     return new_closure(&st->nl.cl);
 605 }
 606
 607 static list_t *tun_apply(closure_t *self, struct cloc loc, dict_t *context,
 608                          list_t *args)
 609 {
 610     return tun_create(self,loc,context,args,TUN_FLAVOUR_GUESS);
 611 }
 612
 613 static list_t *tun_bsd_apply(closure_t *self, struct cloc loc, dict_t *context,
 614                              list_t *args)
 615 {
 616     Message(M_WARNING,"(%s,%d): obsolete use of tun-old; replace with tun "
 617             "and specify flavour \"bsd\".\n",loc.file,loc.line);
 618     return tun_create(self,loc,context,args,TUN_FLAVOUR_BSD);
 619 }
 620
 621 void tun_module(dict_t *dict)
 622 {
 623     add_closure(dict,"tun",tun_apply);
 624     add_closure(dict,"tun-old",tun_bsd_apply);
 625 }