lib/netns_linux.c

   1 /*
   2  * NS functions.
   3  * Copyright (C) 2014 6WIND S.A.
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published
   9  * by the Free Software Foundation; either version 2, or (at your
  10  * option) any later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; see the file COPYING; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <zebra.h>
  23
  24 #ifdef HAVE_NETNS
  25 #undef _GNU_SOURCE
  26 #define _GNU_SOURCE
  27
  28 #include <sched.h>
  29 #endif
  30
  31 /* for basename */
  32 #include <libgen.h>
  33
  34 #include "if.h"
  35 #include "ns.h"
  36 #include "log.h"
  37 #include "memory.h"
  38
  39 #include "command.h"
  40 #include "vty.h"
  41 #include "vrf.h"
  42
  43 DEFINE_MTYPE_STATIC(LIB, NS, "NetNS Context")
  44 DEFINE_MTYPE_STATIC(LIB, NS_NAME, "NetNS Name")
  45
  46 static inline int ns_compare(const struct ns *ns, const struct ns *ns2);
  47 static struct ns *ns_lookup_name_internal(const char *name);
  48
  49 RB_GENERATE(ns_head, ns, entry, ns_compare)
  50
  51 struct ns_head ns_tree = RB_INITIALIZER(&ns_tree);
  52
  53 static struct ns *default_ns;
  54 static int ns_current_ns_fd;
  55 static int ns_default_ns_fd;
  56
  57 static int ns_debug;
  58
  59 #ifndef CLONE_NEWNET
  60 #define CLONE_NEWNET 0x40000000
  61 /* New network namespace (lo, device, names sockets, etc) */
  62 #endif
  63
  64 #ifndef HAVE_SETNS
  65 static inline int setns(int fd, int nstype)
  66 {
  67 #ifdef __NR_setns
  68         return syscall(__NR_setns, fd, nstype);
  69 #else
  70         errno = EINVAL;
  71         return -1;
  72 #endif
  73 }
  74 #endif /* !HAVE_SETNS */
  75
  76 #ifdef HAVE_NETNS
  77 static int have_netns_enabled = -1;
  78 #endif /* HAVE_NETNS */
  79
  80 /* default NS ID value used when VRF backend is not NETNS */
  81 #define NS_DEFAULT_INTERNAL 0
  82
  83 static int have_netns(void)
  84 {
  85 #ifdef HAVE_NETNS
  86         if (have_netns_enabled < 0) {
  87                 int fd = open(NS_DEFAULT_NAME, O_RDONLY);
  88
  89                 if (fd < 0)
  90                         have_netns_enabled = 0;
  91                 else {
  92                         have_netns_enabled = 1;
  93                         close(fd);
  94                 }
  95         }
  96         return have_netns_enabled;
  97 #else
  98         return 0;
  99 #endif
 100 }
 101
 102 /* Holding NS hooks  */
 103 struct ns_master {
 104         int (*ns_new_hook)(struct ns *ns);
 105         int (*ns_delete_hook)(struct ns *ns);
 106         int (*ns_enable_hook)(struct ns *ns);
 107         int (*ns_disable_hook)(struct ns *ns);
 108 } ns_master = {
 109         0,
 110 };
 111
 112 static int ns_is_enabled(struct ns *ns);
 113
 114 static inline int ns_compare(const struct ns *a, const struct ns *b)
 115 {
 116         return (a->ns_id - b->ns_id);
 117 }
 118
 119 /* Look up a NS by identifier. */
 120 static struct ns *ns_lookup_internal(ns_id_t ns_id)
 121 {
 122         struct ns ns;
 123
 124         ns.ns_id = ns_id;
 125         return RB_FIND(ns_head, &ns_tree, &ns);
 126 }
 127
 128 /* Look up a NS by name */
 129 static struct ns *ns_lookup_name_internal(const char *name)
 130 {
 131         struct ns *ns = NULL;
 132
 133         RB_FOREACH (ns, ns_head, &ns_tree) {
 134                 if (ns->name != NULL) {
 135                         if (strcmp(name, ns->name) == 0)
 136                                 return ns;
 137                 }
 138         }
 139         return NULL;
 140 }
 141
 142 static struct ns *ns_get_created_internal(struct ns *ns, char *name,
 143                                           ns_id_t ns_id)
 144 {
 145         int created = 0;
 146         /*
 147          * Initialize interfaces.
 148          */
 149         if (!ns && !name && ns_id != NS_UNKNOWN)
 150                 ns = ns_lookup_internal(ns_id);
 151         if (!ns && name)
 152                 ns = ns_lookup_name_internal(name);
 153         if (!ns) {
 154                 ns = XCALLOC(MTYPE_NS, sizeof(struct ns));
 155                 ns->ns_id = ns_id;
 156                 if (name)
 157                         ns->name = XSTRDUP(MTYPE_NS_NAME, name);
 158                 ns->fd = -1;
 159                 RB_INSERT(ns_head, &ns_tree, ns);
 160                 created = 1;
 161         }
 162         if (ns_id != ns->ns_id) {
 163                 RB_REMOVE(ns_head, &ns_tree, ns);
 164                 ns->ns_id = ns_id;
 165                 RB_INSERT(ns_head, &ns_tree, ns);
 166         }
 167         if (!created)
 168                 return ns;
 169         if (ns_debug) {
 170                 if (ns->ns_id != NS_UNKNOWN)
 171                         zlog_info("NS %u is created.", ns->ns_id);
 172                 else
 173                         zlog_info("NS %s is created.", ns->name);
 174         }
 175         if (ns_master.ns_new_hook)
 176                 (*ns_master.ns_new_hook) (ns);
 177         return ns;
 178 }
 179
 180 /*
 181  * Enable a NS - that is, let the NS be ready to use.
 182  * The NS_ENABLE_HOOK callback will be called to inform
 183  * that they can allocate resources in this NS.
 184  *
 185  * RETURN: 1 - enabled successfully; otherwise, 0.
 186  */
 187 static int ns_enable_internal(struct ns *ns, void (*func)(ns_id_t, void *))
 188 {
 189         if (!ns_is_enabled(ns)) {
 190                 if (have_netns()) {
 191                         ns->fd = open(ns->name, O_RDONLY);
 192                 } else {
 193                         ns->fd = -2;
 194                         /* Remember ns_enable_hook has been called */
 195                         errno = -ENOTSUP;
 196                 }
 197
 198                 if (!ns_is_enabled(ns)) {
 199                         zlog_err("Can not enable NS %u: %s!", ns->ns_id,
 200                                  safe_strerror(errno));
 201                         return 0;
 202                 }
 203
 204                 /* Non default NS. leave */
 205                 if (ns->ns_id == NS_UNKNOWN) {
 206                         zlog_err("Can not enable NS %s %u: Invalid NSID",
 207                                  ns->name, ns->ns_id);
 208                         return 0;
 209                 }
 210                 if (func)
 211                         func(ns->ns_id, (void *)ns->vrf_ctxt);
 212                 if (ns_debug) {
 213                         if (have_netns())
 214                                 zlog_info("NS %u is associated with NETNS %s.",
 215                                           ns->ns_id, ns->name);
 216                         zlog_info("NS %u is enabled.", ns->ns_id);
 217                 }
 218                 /* zebra first receives NS enable event,
 219                  * then VRF enable event
 220                  */
 221                 if (ns_master.ns_enable_hook)
 222                         (*ns_master.ns_enable_hook)(ns);
 223         }
 224
 225         return 1;
 226 }
 227
 228 /*
 229  * Check whether the NS is enabled - that is, whether the NS
 230  * is ready to allocate resources. Currently there's only one
 231  * type of resource: socket.
 232  */
 233 static int ns_is_enabled(struct ns *ns)
 234 {
 235         if (have_netns())
 236                 return ns && ns->fd >= 0;
 237         else
 238                 return ns && ns->fd == -2 && ns->ns_id == NS_DEFAULT;
 239 }
 240
 241 /*
 242  * Disable a NS - that is, let the NS be unusable.
 243  * The NS_DELETE_HOOK callback will be called to inform
 244  * that they must release the resources in the NS.
 245  */
 246 static void ns_disable_internal(struct ns *ns)
 247 {
 248         if (ns_is_enabled(ns)) {
 249                 if (ns_debug)
 250                         zlog_info("NS %u is to be disabled.",
 251                                   ns->ns_id);
 252
 253                 if (ns_master.ns_disable_hook)
 254                         (*ns_master.ns_disable_hook)(ns);
 255
 256                 if (have_netns())
 257                         close(ns->fd);
 258
 259                 ns->fd = -1;
 260         }
 261 }
 262
 263 struct ns *ns_get_created(struct ns *ns, char *name, ns_id_t ns_id)
 264 {
 265         return ns_get_created_internal(ns, name, ns_id);
 266 }
 267
 268 int ns_have_netns(void)
 269 {
 270         return have_netns();
 271 }
 272
 273 /* Delete a NS. This is called in ns_terminate(). */
 274 void ns_delete(struct ns *ns)
 275 {
 276         if (ns_debug)
 277                 zlog_info("NS %u is to be deleted.", ns->ns_id);
 278
 279         ns_disable(ns);
 280
 281         if (ns_master.ns_delete_hook)
 282                 (*ns_master.ns_delete_hook)(ns);
 283
 284         /*
 285          * I'm not entirely sure if the vrf->iflist
 286          * needs to be moved into here or not.
 287          */
 288         // if_terminate (&ns->iflist);
 289
 290         RB_REMOVE(ns_head, &ns_tree, ns);
 291         if (ns->name)
 292                 XFREE(MTYPE_NS_NAME, ns->name);
 293
 294         XFREE(MTYPE_NS, ns);
 295 }
 296
 297 /* Look up the data pointer of the specified VRF. */
 298 void *
 299 ns_info_lookup(ns_id_t ns_id)
 300 {
 301         struct ns *ns = ns_lookup_internal(ns_id);
 302
 303         return ns ? ns->info : NULL;
 304 }
 305
 306 /* Look up a NS by name */
 307 struct ns *ns_lookup_name(const char *name)
 308 {
 309         return ns_lookup_name_internal(name);
 310 }
 311
 312 int ns_enable(struct ns *ns, void (*func)(ns_id_t, void *))
 313 {
 314         return ns_enable_internal(ns, func);
 315 }
 316
 317 void ns_disable(struct ns *ns)
 318 {
 319         return ns_disable_internal(ns);
 320 }
 321
 322 struct ns *ns_lookup(ns_id_t ns_id)
 323 {
 324         return ns_lookup_internal(ns_id);
 325 }
 326
 327 void ns_walk_func(int (*func)(struct ns *))
 328 {
 329         struct ns *ns = NULL;
 330
 331         RB_FOREACH (ns, ns_head, &ns_tree)
 332                 func(ns);
 333 }
 334
 335 const char *ns_get_name(struct ns *ns)
 336 {
 337         if (!ns)
 338                 return NULL;
 339         return ns->name;
 340 }
 341
 342 /* Add a NS hook. Please add hooks before calling ns_init(). */
 343 void ns_add_hook(int type, int (*func)(struct ns *))
 344 {
 345         switch (type) {
 346         case NS_NEW_HOOK:
 347                 ns_master.ns_new_hook = func;
 348                 break;
 349         case NS_DELETE_HOOK:
 350                 ns_master.ns_delete_hook = func;
 351                 break;
 352         case NS_ENABLE_HOOK:
 353                 ns_master.ns_enable_hook = func;
 354                 break;
 355         case NS_DISABLE_HOOK:
 356                 ns_master.ns_disable_hook = func;
 357                 break;
 358         default:
 359                 break;
 360         }
 361 }
 362
 363 /*
 364  * NS realization with NETNS
 365  */
 366
 367 char *ns_netns_pathname(struct vty *vty, const char *name)
 368 {
 369         static char pathname[PATH_MAX];
 370         char *result;
 371         char *check_base;
 372
 373         if (name[0] == '/') /* absolute pathname */
 374                 result = realpath(name, pathname);
 375         else {
 376                 /* relevant pathname */
 377                 char tmp_name[PATH_MAX];
 378
 379                 snprintf(tmp_name, PATH_MAX, "%s/%s", NS_RUN_DIR, name);
 380                 result = realpath(tmp_name, pathname);
 381         }
 382
 383         if (!result) {
 384                 if (vty)
 385                         vty_out(vty, "Invalid pathname: %s\n",
 386                                 safe_strerror(errno));
 387                 else
 388                         zlog_warn("Invalid pathname: %s",
 389                                   safe_strerror(errno));
 390                 return NULL;
 391         }
 392         check_base = basename(pathname);
 393         if (check_base != NULL && strlen(check_base) + 1 > NS_NAMSIZ) {
 394                 if (vty)
 395                         vty_out(vty, "NS name (%s) invalid: too long (>%d)\n",
 396                                 check_base, NS_NAMSIZ-1);
 397                 else
 398                         zlog_warn("NS name (%s) invalid: too long (>%d)",
 399                                   check_base, NS_NAMSIZ-1);
 400                 return NULL;
 401         }
 402         return pathname;
 403 }
 404
 405 void ns_init(void)
 406 {
 407         static int ns_initialised;
 408
 409         ns_debug = 0;
 410         /* silently return as initialisation done */
 411         if (ns_initialised == 1)
 412                 return;
 413         errno = 0;
 414 #ifdef HAVE_NETNS
 415         if (have_netns_enabled < 0)
 416                 ns_default_ns_fd = open(NS_DEFAULT_NAME, O_RDONLY);
 417         else
 418                 ns_default_ns_fd = -1;
 419 #else
 420         ns_default_ns_fd = -1;
 421         default_ns = NULL;
 422 #endif /* HAVE_NETNS */
 423         if (ns_default_ns_fd == -1)
 424                 zlog_err("NS initialisation failure (%s)",
 425                          safe_strerror(errno));
 426         ns_current_ns_fd = -1;
 427         ns_initialised = 1;
 428 }
 429
 430 /* Initialize NS module. */
 431 void ns_init_management(ns_id_t default_ns_id)
 432 {
 433         int fd;
 434
 435         ns_init();
 436         default_ns = ns_get_created_internal(NULL, NULL, default_ns_id);
 437         if (!default_ns) {
 438                 zlog_err("%s: failed to create the default NS!",
 439                          __func__);
 440                 exit(1);
 441         }
 442         if (have_netns()) {
 443                 fd = open(NS_DEFAULT_NAME, O_RDONLY);
 444                 default_ns->fd = fd;
 445         }
 446         /* Set the default NS name. */
 447         default_ns->name = XSTRDUP(MTYPE_NS_NAME, NS_DEFAULT_NAME);
 448         if (ns_debug)
 449                 zlog_info("%s: default NSID is %u",
 450                           __func__, default_ns->ns_id);
 451
 452         /* Enable the default NS. */
 453         if (!ns_enable(default_ns, NULL)) {
 454                 zlog_err("%s: failed to enable the default NS!",
 455                          __func__);
 456                 exit(1);
 457         }
 458 }
 459
 460 /* Terminate NS module. */
 461 void ns_terminate(void)
 462 {
 463         struct ns *ns;
 464
 465         while (!RB_EMPTY(ns_head, &ns_tree)) {
 466                 ns = RB_ROOT(ns_head, &ns_tree);
 467
 468                 ns_delete(ns);
 469         }
 470 }
 471
 472 int ns_switch_to_netns(const char *name)
 473 {
 474         int ret;
 475         int fd;
 476
 477         if (name == NULL)
 478                 return -1;
 479         if (ns_default_ns_fd == -1)
 480                 return -1;
 481         fd = open(name, O_RDONLY);
 482         if (fd == -1) {
 483                 errno = EINVAL;
 484                 return -1;
 485         }
 486         ret = setns(fd, CLONE_NEWNET);
 487         ns_current_ns_fd = fd;
 488         close(fd);
 489         return ret;
 490 }
 491
 492 /* returns 1 if switch() was not called before
 493  * return status of setns() otherwise
 494  */
 495 int ns_switchback_to_initial(void)
 496 {
 497         if (ns_current_ns_fd != -1 && ns_default_ns_fd != -1) {
 498                 int ret;
 499
 500                 ret = setns(ns_default_ns_fd, CLONE_NEWNET);
 501                 ns_current_ns_fd = -1;
 502                 return ret;
 503         }
 504         /* silently ignore if setns() is not called */
 505         return 1;
 506 }
 507
 508 /* Create a socket for the NS. */
 509 int ns_socket(int domain, int type, int protocol, ns_id_t ns_id)
 510 {
 511         struct ns *ns = ns_lookup(ns_id);
 512         int ret;
 513
 514         if (!ns || !ns_is_enabled(ns)) {
 515                 errno = EINVAL;
 516                 return -1;
 517         }
 518         if (have_netns()) {
 519                 ret = (ns_id != NS_DEFAULT) ? setns(ns->fd, CLONE_NEWNET) : 0;
 520                 if (ret >= 0) {
 521                         ret = socket(domain, type, protocol);
 522                         if (ns_id != NS_DEFAULT) {
 523                                 setns(ns_lookup(NS_DEFAULT)->fd, CLONE_NEWNET);
 524                                 ns_current_ns_fd = ns_id;
 525                         }
 526                 }
 527         } else
 528                 ret = socket(domain, type, protocol);
 529
 530         return ret;
 531 }
 532
 533 ns_id_t ns_get_default_id(void)
 534 {
 535         if (default_ns)
 536                 return default_ns->ns_id;
 537         return NS_UNKNOWN;
 538 }
 539