zebra/zebra_netns_notify.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Zebra NS collector and notifier for Network NameSpaces
   4  * Copyright (C) 2017 6WIND
   5  */
   6
   7 #include <zebra.h>
   8
   9 #ifdef HAVE_NETLINK
  10 #ifdef HAVE_NETNS
  11 #undef _GNU_SOURCE
  12 #define _GNU_SOURCE
  13
  14 #include <sched.h>
  15 #endif
  16 #include <dirent.h>
  17 #include <sys/inotify.h>
  18 #include <sys/stat.h>
  19
  20 #include "frrevent.h"
  21 #include "ns.h"
  22 #include "command.h"
  23 #include "memory.h"
  24 #include "lib_errors.h"
  25
  26 #include "zebra_router.h"
  27 #endif /* defined(HAVE_NETLINK) */
  28
  29 #include "zebra_netns_notify.h"
  30 #include "zebra_netns_id.h"
  31 #include "zebra_errors.h"
  32 #include "interface.h"
  33
  34 #ifdef HAVE_NETLINK
  35
  36 /* upon creation of folder under /var/run/netns,
  37  * wait that netns context is bound to
  38  * that folder 10 seconds
  39  */
  40 #define ZEBRA_NS_POLLING_INTERVAL_MSEC     1000
  41 #define ZEBRA_NS_POLLING_MAX_RETRIES  200
  42
  43 DEFINE_MTYPE_STATIC(ZEBRA, NETNS_MISC, "ZebraNetNSInfo");
  44 static struct event *zebra_netns_notify_current;
  45
  46 struct zebra_netns_info {
  47         const char *netnspath;
  48         unsigned int retries;
  49 };
  50
  51 static void zebra_ns_ready_read(struct event *t);
  52 static void zebra_ns_notify_create_context_from_entry_name(const char *name);
  53 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
  54                                   int stop_retry);
  55 static void zebra_ns_notify_read(struct event *t);
  56
  57 static struct vrf *vrf_handler_create(struct vty *vty, const char *vrfname)
  58 {
  59         if (strlen(vrfname) > VRF_NAMSIZ) {
  60                 flog_warn(EC_LIB_VRF_LENGTH,
  61                           "%% VRF name %s invalid: length exceeds %d bytes",
  62                           vrfname, VRF_NAMSIZ);
  63                 return NULL;
  64         }
  65
  66         return vrf_get(VRF_UNKNOWN, vrfname);
  67 }
  68
  69 static void zebra_ns_notify_create_context_from_entry_name(const char *name)
  70 {
  71         char *netnspath = ns_netns_pathname(NULL, name);
  72         struct vrf *vrf;
  73         int ret;
  74         ns_id_t ns_id, ns_id_external, ns_id_relative = NS_UNKNOWN;
  75         struct ns *default_ns;
  76
  77         if (netnspath == NULL)
  78                 return;
  79
  80         frr_with_privs(&zserv_privs) {
  81                 ns_id = zebra_ns_id_get(netnspath, -1);
  82         }
  83         if (ns_id == NS_UNKNOWN)
  84                 return;
  85         ns_id_external = ns_map_nsid_with_external(ns_id, true);
  86         /* if VRF with NS ID already present */
  87         vrf = vrf_lookup_by_id((vrf_id_t)ns_id_external);
  88         if (vrf) {
  89                 zlog_debug(
  90                         "NS notify : same NSID used by VRF %s. Ignore NS %s creation",
  91                         vrf->name, netnspath);
  92                 return;
  93         }
  94         vrf = vrf_handler_create(NULL, name);
  95         if (!vrf) {
  96                 flog_warn(EC_ZEBRA_NS_VRF_CREATION_FAILED,
  97                           "NS notify : failed to create VRF %s", name);
  98                 ns_map_nsid_with_external(ns_id, false);
  99                 return;
 100         }
 101
 102         default_ns = ns_get_default();
 103
 104         /* force kernel ns_id creation in that new vrf */
 105         frr_with_privs(&zserv_privs) {
 106                 ns_switch_to_netns(netnspath);
 107                 ns_id_relative = zebra_ns_id_get(NULL, default_ns->fd);
 108                 ns_switchback_to_initial();
 109         }
 110
 111         frr_with_privs(&zserv_privs) {
 112                 ret = zebra_vrf_netns_handler_create(NULL, vrf, netnspath,
 113                                                      ns_id_external, ns_id,
 114                                                      ns_id_relative);
 115         }
 116         if (ret != CMD_SUCCESS) {
 117                 flog_warn(EC_ZEBRA_NS_VRF_CREATION_FAILED,
 118                           "NS notify : failed to create NS %s", netnspath);
 119                 ns_map_nsid_with_external(ns_id, false);
 120                 vrf_delete(vrf);
 121                 return;
 122         }
 123         zlog_info("NS notify : created VRF %s NS %s", name, netnspath);
 124 }
 125
 126 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
 127                                   int stop_retry)
 128 {
 129         void *ns_path_ptr = (void *)zns_info->netnspath;
 130
 131         if (stop_retry) {
 132                 XFREE(MTYPE_NETNS_MISC, ns_path_ptr);
 133                 XFREE(MTYPE_NETNS_MISC, zns_info);
 134                 return 0;
 135         }
 136         event_add_timer_msec(zrouter.master, zebra_ns_ready_read,
 137                              (void *)zns_info, ZEBRA_NS_POLLING_INTERVAL_MSEC,
 138                              NULL);
 139         return 0;
 140 }
 141
 142 static int zebra_ns_delete(char *name)
 143 {
 144         struct vrf *vrf = vrf_lookup_by_name(name);
 145         struct interface *ifp, *tmp;
 146         struct ns *ns;
 147
 148         if (!vrf) {
 149                 flog_warn(EC_ZEBRA_NS_DELETION_FAILED_NO_VRF,
 150                           "NS notify : no VRF found using NS %s", name);
 151                 return 0;
 152         }
 153
 154         /*
 155          * We don't receive interface down/delete notifications from kernel
 156          * when a netns is deleted. Therefore we have to manually replicate
 157          * the necessary actions here.
 158          */
 159         RB_FOREACH_SAFE (ifp, if_name_head, &vrf->ifaces_by_name, tmp) {
 160                 if (!CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE))
 161                         continue;
 162
 163                 if (if_is_no_ptm_operative(ifp)) {
 164                         UNSET_FLAG(ifp->flags, IFF_RUNNING);
 165                         if_down(ifp);
 166                 }
 167
 168                 if (IS_ZEBRA_IF_BOND(ifp))
 169                         zebra_l2if_update_bond(ifp, false);
 170                 if (IS_ZEBRA_IF_BOND_SLAVE(ifp))
 171                         zebra_l2if_update_bond_slave(ifp, IFINDEX_INTERNAL,
 172                                                      false);
 173                 /* Special handling for bridge or VxLAN interfaces. */
 174                 if (IS_ZEBRA_IF_BRIDGE(ifp))
 175                         zebra_l2_bridge_del(ifp);
 176                 else if (IS_ZEBRA_IF_VXLAN(ifp))
 177                         zebra_l2_vxlanif_del(ifp);
 178
 179                 UNSET_FLAG(ifp->flags, IFF_UP);
 180                 if_delete_update(&ifp);
 181         }
 182
 183         ns = (struct ns *)vrf->ns_ctxt;
 184         /* the deletion order is the same
 185          * as the one used when siging signal is received
 186          */
 187         vrf->ns_ctxt = NULL;
 188         vrf_delete(vrf);
 189         if (ns)
 190                 ns_delete(ns);
 191
 192         zlog_info("NS notify : deleted VRF %s", name);
 193         return 0;
 194 }
 195
 196 static int zebra_ns_notify_self_identify(struct stat *netst)
 197 {
 198         char net_path[PATH_MAX];
 199         int netns;
 200
 201         snprintf(net_path, sizeof(net_path), "/proc/self/ns/net");
 202         netns = open(net_path, O_RDONLY);
 203         if (netns < 0)
 204                 return -1;
 205         if (fstat(netns, netst) < 0) {
 206                 close(netns);
 207                 return -1;
 208         }
 209         close(netns);
 210         return 0;
 211 }
 212
 213 static bool zebra_ns_notify_is_default_netns(const char *name)
 214 {
 215         struct stat default_netns_stat;
 216         struct stat st;
 217         char netnspath[PATH_MAX];
 218
 219         if (zebra_ns_notify_self_identify(&default_netns_stat))
 220                 return false;
 221
 222         memset(&st, 0, sizeof(st));
 223         snprintf(netnspath, sizeof(netnspath), "%s/%s", NS_RUN_DIR, name);
 224         /* compare with local stat */
 225         if (stat(netnspath, &st) == 0 &&
 226             (st.st_dev == default_netns_stat.st_dev) &&
 227             (st.st_ino == default_netns_stat.st_ino))
 228                 return true;
 229         return false;
 230 }
 231
 232 static void zebra_ns_ready_read(struct event *t)
 233 {
 234         struct zebra_netns_info *zns_info = EVENT_ARG(t);
 235         const char *netnspath;
 236         int err, stop_retry = 0;
 237
 238         if (!zns_info)
 239                 return;
 240         if (!zns_info->netnspath) {
 241                 XFREE(MTYPE_NETNS_MISC, zns_info);
 242                 return;
 243         }
 244         netnspath = zns_info->netnspath;
 245         if (--zns_info->retries == 0)
 246                 stop_retry = 1;
 247         frr_with_privs(&zserv_privs) {
 248                 err = ns_switch_to_netns(netnspath);
 249         }
 250         if (err < 0) {
 251                 zebra_ns_continue_read(zns_info, stop_retry);
 252                 return;
 253         }
 254
 255         /* go back to default ns */
 256         frr_with_privs(&zserv_privs) {
 257                 err = ns_switchback_to_initial();
 258         }
 259         if (err < 0) {
 260                 zebra_ns_continue_read(zns_info, stop_retry);
 261                 return;
 262         }
 263
 264         /* check default name is not already set */
 265         if (strmatch(VRF_DEFAULT_NAME, basename(netnspath))) {
 266                 zlog_warn("NS notify : NS %s is already default VRF.Cancel VRF Creation", basename(netnspath));
 267                 zebra_ns_continue_read(zns_info, 1);
 268                 return;
 269         }
 270         if (zebra_ns_notify_is_default_netns(basename(netnspath))) {
 271                 zlog_warn(
 272                         "NS notify : NS %s is default VRF. Ignore VRF creation",
 273                         basename(netnspath));
 274                 zebra_ns_continue_read(zns_info, 1);
 275                 return;
 276         }
 277
 278         /* success : close fd and create zns context */
 279         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 280         zebra_ns_continue_read(zns_info, 1);
 281 }
 282
 283 static void zebra_ns_notify_read(struct event *t)
 284 {
 285         int fd_monitor = EVENT_FD(t);
 286         struct inotify_event *event;
 287         char buf[BUFSIZ];
 288         ssize_t len;
 289         char event_name[NAME_MAX + 1];
 290
 291         event_add_read(zrouter.master, zebra_ns_notify_read, NULL, fd_monitor,
 292                        &zebra_netns_notify_current);
 293         len = read(fd_monitor, buf, sizeof(buf));
 294         if (len < 0) {
 295                 flog_err_sys(EC_ZEBRA_NS_NOTIFY_READ,
 296                              "NS notify read: failed to read (%s)",
 297                              safe_strerror(errno));
 298                 return;
 299         }
 300         for (event = (struct inotify_event *)buf; (char *)event < &buf[len];
 301              event = (struct inotify_event *)((char *)event + sizeof(*event)
 302                                               + event->len)) {
 303                 char *netnspath;
 304                 struct zebra_netns_info *netnsinfo;
 305
 306                 if (!(event->mask & (IN_CREATE | IN_DELETE)))
 307                         continue;
 308
 309                 if (offsetof(struct inotify_event, name) + event->len
 310                     >= sizeof(buf)) {
 311                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 312                                  "NS notify read: buffer underflow");
 313                         break;
 314                 }
 315
 316                 if (strnlen(event->name, event->len) == event->len) {
 317                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 318                                  "NS notify error: bad event name");
 319                         break;
 320                 }
 321
 322                 /*
 323                  * Coverity Scan extra steps to satisfy `STRING_NULL` warning:
 324                  * - Make sure event name is present by checking `len != 0`
 325                  * - Event name length must be at most `NAME_MAX + 1`
 326                  *   (null byte inclusive)
 327                  * - Copy event name to a stack buffer to make sure it
 328                  *   includes the null byte. `event->name` includes at least
 329                  *   one null byte and `event->len` accounts the null bytes,
 330                  *   so the operation after `memcpy` will look like a
 331                  *   truncation to satisfy Coverity Scan null byte ending.
 332                  *
 333                  *   Example:
 334                  *   if `event->name` is `abc\0` and `event->len` is 4,
 335                  *   `memcpy` will copy the 4 bytes and then we set the
 336                  *   null byte again at the position 4.
 337                  *
 338                  * For more information please read inotify(7) man page.
 339                  */
 340                 if (event->len == 0)
 341                         continue;
 342
 343                 if (event->len > sizeof(event_name)) {
 344                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 345                                  "NS notify error: unexpected big event name");
 346                         break;
 347                 }
 348
 349                 memcpy(event_name, event->name, event->len);
 350                 event_name[event->len - 1] = 0;
 351
 352                 if (event->mask & IN_DELETE) {
 353                         zebra_ns_delete(event_name);
 354                         continue;
 355                 }
 356                 netnspath = ns_netns_pathname(NULL, event_name);
 357                 if (!netnspath)
 358                         continue;
 359                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 360                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 361                                     sizeof(struct zebra_netns_info));
 362                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 363                 netnsinfo->netnspath = netnspath;
 364                 event_add_timer_msec(zrouter.master, zebra_ns_ready_read,
 365                                      (void *)netnsinfo, 0, NULL);
 366         }
 367 }
 368
 369 void zebra_ns_notify_parse(void)
 370 {
 371         struct dirent *dent;
 372         DIR *srcdir = opendir(NS_RUN_DIR);
 373
 374         if (srcdir == NULL) {
 375                 flog_err_sys(EC_LIB_SYSTEM_CALL,
 376                              "NS parsing init: failed to parse %s", NS_RUN_DIR);
 377                 return;
 378         }
 379         while ((dent = readdir(srcdir)) != NULL) {
 380                 struct stat st;
 381
 382                 if (strcmp(dent->d_name, ".") == 0
 383                     || strcmp(dent->d_name, "..") == 0)
 384                         continue;
 385                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 386                         flog_err_sys(
 387                                 EC_LIB_SYSTEM_CALL,
 388                                 "NS parsing init: failed to parse entry %s",
 389                                 dent->d_name);
 390                         continue;
 391                 }
 392                 if (S_ISDIR(st.st_mode)) {
 393                         zlog_debug("NS parsing init: %s is not a NS",
 394                                    dent->d_name);
 395                         continue;
 396                 }
 397                 /* check default name is not already set */
 398                 if (strmatch(VRF_DEFAULT_NAME, basename(dent->d_name))) {
 399                         zlog_warn("NS notify : NS %s is already default VRF.Cancel VRF Creation", dent->d_name);
 400                         continue;
 401                 }
 402                 if (zebra_ns_notify_is_default_netns(dent->d_name)) {
 403                         zlog_warn(
 404                                 "NS notify : NS %s is default VRF. Ignore VRF creation",
 405                                 dent->d_name);
 406                         continue;
 407                 }
 408                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 409         }
 410         closedir(srcdir);
 411 }
 412
 413 void zebra_ns_notify_init(void)
 414 {
 415         int fd_monitor;
 416
 417         fd_monitor = inotify_init();
 418         if (fd_monitor < 0) {
 419                 flog_err_sys(
 420                         EC_LIB_SYSTEM_CALL,
 421                         "NS notify init: failed to initialize inotify (%s)",
 422                         safe_strerror(errno));
 423         }
 424         if (inotify_add_watch(fd_monitor, NS_RUN_DIR,
 425                               IN_CREATE | IN_DELETE) < 0) {
 426                 flog_err_sys(EC_LIB_SYSTEM_CALL,
 427                              "NS notify watch: failed to add watch (%s)",
 428                              safe_strerror(errno));
 429         }
 430         event_add_read(zrouter.master, zebra_ns_notify_read, NULL, fd_monitor,
 431                        &zebra_netns_notify_current);
 432 }
 433
 434 void zebra_ns_notify_close(void)
 435 {
 436         if (zebra_netns_notify_current == NULL)
 437                 return;
 438
 439         int fd = 0;
 440
 441         if (zebra_netns_notify_current->u.fd > 0)
 442                 fd = zebra_netns_notify_current->u.fd;
 443
 444         if (zebra_netns_notify_current->master != NULL)
 445                 EVENT_OFF(zebra_netns_notify_current);
 446
 447         /* auto-removal of notify items */
 448         if (fd > 0)
 449                 close(fd);
 450 }
 451
 452 #else
 453 void zebra_ns_notify_parse(void)
 454 {
 455 }
 456
 457 void zebra_ns_notify_init(void)
 458 {
 459 }
 460
 461 void zebra_ns_notify_close(void)
 462 {
 463 }
 464 #endif /* !HAVE_NETLINK */