zebra/zebra_netns_notify.c

   1 /*
   2  * Zebra NS collector and notifier for Network NameSpaces
   3  * Copyright (C) 2017 6WIND
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; either version 2 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <zebra.h>
  21
  22 #ifdef HAVE_NETLINK
  23 #ifdef HAVE_NETNS
  24 #undef _GNU_SOURCE
  25 #define _GNU_SOURCE
  26
  27 #include <sched.h>
  28 #endif
  29 #include <dirent.h>
  30 #include <sys/inotify.h>
  31 #include <sys/stat.h>
  32
  33 #include "thread.h"
  34 #include "ns.h"
  35 #include "command.h"
  36 #include "memory.h"
  37 #include "lib_errors.h"
  38
  39 #include "zebra_router.h"
  40 #endif /* defined(HAVE_NETLINK) */
  41
  42 #include "zebra_netns_notify.h"
  43 #include "zebra_netns_id.h"
  44 #include "zebra_errors.h"
  45 #include "interface.h"
  46
  47 #ifdef HAVE_NETLINK
  48
  49 /* upon creation of folder under /var/run/netns,
  50  * wait that netns context is bound to
  51  * that folder 10 seconds
  52  */
  53 #define ZEBRA_NS_POLLING_INTERVAL_MSEC     1000
  54 #define ZEBRA_NS_POLLING_MAX_RETRIES  200
  55
  56 DEFINE_MTYPE_STATIC(ZEBRA, NETNS_MISC, "ZebraNetNSInfo");
  57 static struct thread *zebra_netns_notify_current;
  58
  59 struct zebra_netns_info {
  60         const char *netnspath;
  61         unsigned int retries;
  62 };
  63
  64 static void zebra_ns_ready_read(struct thread *t);
  65 static void zebra_ns_notify_create_context_from_entry_name(const char *name);
  66 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
  67                                   int stop_retry);
  68 static void zebra_ns_notify_read(struct thread *t);
  69
  70 static struct vrf *vrf_handler_create(struct vty *vty, const char *vrfname)
  71 {
  72         if (strlen(vrfname) > VRF_NAMSIZ) {
  73                 flog_warn(EC_LIB_VRF_LENGTH,
  74                           "%% VRF name %s invalid: length exceeds %d bytes",
  75                           vrfname, VRF_NAMSIZ);
  76                 return NULL;
  77         }
  78
  79         return vrf_get(VRF_UNKNOWN, vrfname);
  80 }
  81
  82 static void zebra_ns_notify_create_context_from_entry_name(const char *name)
  83 {
  84         char *netnspath = ns_netns_pathname(NULL, name);
  85         struct vrf *vrf;
  86         int ret;
  87         ns_id_t ns_id, ns_id_external, ns_id_relative = NS_UNKNOWN;
  88         struct ns *default_ns;
  89
  90         if (netnspath == NULL)
  91                 return;
  92
  93         frr_with_privs(&zserv_privs) {
  94                 ns_id = zebra_ns_id_get(netnspath, -1);
  95         }
  96         if (ns_id == NS_UNKNOWN)
  97                 return;
  98         ns_id_external = ns_map_nsid_with_external(ns_id, true);
  99         /* if VRF with NS ID already present */
 100         vrf = vrf_lookup_by_id((vrf_id_t)ns_id_external);
 101         if (vrf) {
 102                 zlog_debug(
 103                         "NS notify : same NSID used by VRF %s. Ignore NS %s creation",
 104                         vrf->name, netnspath);
 105                 return;
 106         }
 107         vrf = vrf_handler_create(NULL, name);
 108         if (!vrf) {
 109                 flog_warn(EC_ZEBRA_NS_VRF_CREATION_FAILED,
 110                           "NS notify : failed to create VRF %s", name);
 111                 ns_map_nsid_with_external(ns_id, false);
 112                 return;
 113         }
 114
 115         default_ns = ns_get_default();
 116
 117         /* force kernel ns_id creation in that new vrf */
 118         frr_with_privs(&zserv_privs) {
 119                 ns_switch_to_netns(netnspath);
 120                 ns_id_relative = zebra_ns_id_get(NULL, default_ns->fd);
 121                 ns_switchback_to_initial();
 122         }
 123
 124         frr_with_privs(&zserv_privs) {
 125                 ret = zebra_vrf_netns_handler_create(NULL, vrf, netnspath,
 126                                                      ns_id_external, ns_id,
 127                                                      ns_id_relative);
 128         }
 129         if (ret != CMD_SUCCESS) {
 130                 flog_warn(EC_ZEBRA_NS_VRF_CREATION_FAILED,
 131                           "NS notify : failed to create NS %s", netnspath);
 132                 ns_map_nsid_with_external(ns_id, false);
 133                 vrf_delete(vrf);
 134                 return;
 135         }
 136         zlog_info("NS notify : created VRF %s NS %s", name, netnspath);
 137 }
 138
 139 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
 140                                   int stop_retry)
 141 {
 142         void *ns_path_ptr = (void *)zns_info->netnspath;
 143
 144         if (stop_retry) {
 145                 XFREE(MTYPE_NETNS_MISC, ns_path_ptr);
 146                 XFREE(MTYPE_NETNS_MISC, zns_info);
 147                 return 0;
 148         }
 149         thread_add_timer_msec(zrouter.master, zebra_ns_ready_read,
 150                               (void *)zns_info, ZEBRA_NS_POLLING_INTERVAL_MSEC,
 151                               NULL);
 152         return 0;
 153 }
 154
 155 static int zebra_ns_delete(char *name)
 156 {
 157         struct vrf *vrf = vrf_lookup_by_name(name);
 158         struct interface *ifp, *tmp;
 159         struct ns *ns;
 160
 161         if (!vrf) {
 162                 flog_warn(EC_ZEBRA_NS_DELETION_FAILED_NO_VRF,
 163                           "NS notify : no VRF found using NS %s", name);
 164                 return 0;
 165         }
 166
 167         /*
 168          * We don't receive interface down/delete notifications from kernel
 169          * when a netns is deleted. Therefore we have to manually replicate
 170          * the necessary actions here.
 171          */
 172         RB_FOREACH_SAFE (ifp, if_name_head, &vrf->ifaces_by_name, tmp) {
 173                 if (!CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE))
 174                         continue;
 175
 176                 if (if_is_no_ptm_operative(ifp)) {
 177                         UNSET_FLAG(ifp->flags, IFF_RUNNING);
 178                         if_down(ifp);
 179                 }
 180
 181                 UNSET_FLAG(ifp->flags, IFF_UP);
 182                 if_delete_update(&ifp);
 183         }
 184
 185         ns = (struct ns *)vrf->ns_ctxt;
 186         /* the deletion order is the same
 187          * as the one used when siging signal is received
 188          */
 189         vrf->ns_ctxt = NULL;
 190         vrf_delete(vrf);
 191         if (ns)
 192                 ns_delete(ns);
 193
 194         zlog_info("NS notify : deleted VRF %s", name);
 195         return 0;
 196 }
 197
 198 static int zebra_ns_notify_self_identify(struct stat *netst)
 199 {
 200         char net_path[PATH_MAX];
 201         int netns;
 202
 203         snprintf(net_path, sizeof(net_path), "/proc/self/ns/net");
 204         netns = open(net_path, O_RDONLY);
 205         if (netns < 0)
 206                 return -1;
 207         if (fstat(netns, netst) < 0) {
 208                 close(netns);
 209                 return -1;
 210         }
 211         close(netns);
 212         return 0;
 213 }
 214
 215 static bool zebra_ns_notify_is_default_netns(const char *name)
 216 {
 217         struct stat default_netns_stat;
 218         struct stat st;
 219         char netnspath[PATH_MAX];
 220
 221         if (zebra_ns_notify_self_identify(&default_netns_stat))
 222                 return false;
 223
 224         memset(&st, 0, sizeof(struct stat));
 225         snprintf(netnspath, sizeof(netnspath), "%s/%s", NS_RUN_DIR, name);
 226         /* compare with local stat */
 227         if (stat(netnspath, &st) == 0 &&
 228             (st.st_dev == default_netns_stat.st_dev) &&
 229             (st.st_ino == default_netns_stat.st_ino))
 230                 return true;
 231         return false;
 232 }
 233
 234 static void zebra_ns_ready_read(struct thread *t)
 235 {
 236         struct zebra_netns_info *zns_info = THREAD_ARG(t);
 237         const char *netnspath;
 238         int err, stop_retry = 0;
 239
 240         if (!zns_info)
 241                 return;
 242         if (!zns_info->netnspath) {
 243                 XFREE(MTYPE_NETNS_MISC, zns_info);
 244                 return;
 245         }
 246         netnspath = zns_info->netnspath;
 247         if (--zns_info->retries == 0)
 248                 stop_retry = 1;
 249         frr_with_privs(&zserv_privs) {
 250                 err = ns_switch_to_netns(netnspath);
 251         }
 252         if (err < 0) {
 253                 zebra_ns_continue_read(zns_info, stop_retry);
 254                 return;
 255         }
 256
 257         /* go back to default ns */
 258         frr_with_privs(&zserv_privs) {
 259                 err = ns_switchback_to_initial();
 260         }
 261         if (err < 0) {
 262                 zebra_ns_continue_read(zns_info, stop_retry);
 263                 return;
 264         }
 265
 266         /* check default name is not already set */
 267         if (strmatch(VRF_DEFAULT_NAME, basename(netnspath))) {
 268                 zlog_warn("NS notify : NS %s is already default VRF.Cancel VRF Creation", basename(netnspath));
 269                 zebra_ns_continue_read(zns_info, 1);
 270                 return;
 271         }
 272         if (zebra_ns_notify_is_default_netns(basename(netnspath))) {
 273                 zlog_warn(
 274                         "NS notify : NS %s is default VRF. Ignore VRF creation",
 275                         basename(netnspath));
 276                 zebra_ns_continue_read(zns_info, 1);
 277                 return;
 278         }
 279
 280         /* success : close fd and create zns context */
 281         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 282         zebra_ns_continue_read(zns_info, 1);
 283 }
 284
 285 static void zebra_ns_notify_read(struct thread *t)
 286 {
 287         int fd_monitor = THREAD_FD(t);
 288         struct inotify_event *event;
 289         char buf[BUFSIZ];
 290         ssize_t len;
 291
 292         thread_add_read(zrouter.master, zebra_ns_notify_read, NULL, fd_monitor,
 293                         &zebra_netns_notify_current);
 294         len = read(fd_monitor, buf, sizeof(buf));
 295         if (len < 0) {
 296                 flog_err_sys(EC_ZEBRA_NS_NOTIFY_READ,
 297                              "NS notify read: failed to read (%s)",
 298                              safe_strerror(errno));
 299                 return;
 300         }
 301         for (event = (struct inotify_event *)buf; (char *)event < &buf[len];
 302              event = (struct inotify_event *)((char *)event + sizeof(*event)
 303                                               + event->len)) {
 304                 char *netnspath;
 305                 struct zebra_netns_info *netnsinfo;
 306
 307                 if (!(event->mask & (IN_CREATE | IN_DELETE)))
 308                         continue;
 309
 310                 if (offsetof(struct inotify_event, name) + event->len
 311                     >= sizeof(buf)) {
 312                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 313                                  "NS notify read: buffer underflow");
 314                         break;
 315                 }
 316
 317                 if (strnlen(event->name, event->len) == event->len) {
 318                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 319                                  "NS notify error: bad event name");
 320                         break;
 321                 }
 322
 323                 if (event->mask & IN_DELETE) {
 324                         zebra_ns_delete(event->name);
 325                         continue;
 326                 }
 327                 netnspath = ns_netns_pathname(NULL, event->name);
 328                 if (!netnspath)
 329                         continue;
 330                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 331                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 332                                     sizeof(struct zebra_netns_info));
 333                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 334                 netnsinfo->netnspath = netnspath;
 335                 thread_add_timer_msec(zrouter.master, zebra_ns_ready_read,
 336                                       (void *)netnsinfo, 0, NULL);
 337         }
 338 }
 339
 340 void zebra_ns_notify_parse(void)
 341 {
 342         struct dirent *dent;
 343         DIR *srcdir = opendir(NS_RUN_DIR);
 344
 345         if (srcdir == NULL) {
 346                 flog_err_sys(EC_LIB_SYSTEM_CALL,
 347                              "NS parsing init: failed to parse %s", NS_RUN_DIR);
 348                 return;
 349         }
 350         while ((dent = readdir(srcdir)) != NULL) {
 351                 struct stat st;
 352
 353                 if (strcmp(dent->d_name, ".") == 0
 354                     || strcmp(dent->d_name, "..") == 0)
 355                         continue;
 356                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 357                         flog_err_sys(
 358                                 EC_LIB_SYSTEM_CALL,
 359                                 "NS parsing init: failed to parse entry %s",
 360                                 dent->d_name);
 361                         continue;
 362                 }
 363                 if (S_ISDIR(st.st_mode)) {
 364                         zlog_debug("NS parsing init: %s is not a NS",
 365                                    dent->d_name);
 366                         continue;
 367                 }
 368                 /* check default name is not already set */
 369                 if (strmatch(VRF_DEFAULT_NAME, basename(dent->d_name))) {
 370                         zlog_warn("NS notify : NS %s is already default VRF.Cancel VRF Creation", dent->d_name);
 371                         continue;
 372                 }
 373                 if (zebra_ns_notify_is_default_netns(dent->d_name)) {
 374                         zlog_warn(
 375                                 "NS notify : NS %s is default VRF. Ignore VRF creation",
 376                                 dent->d_name);
 377                         continue;
 378                 }
 379                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 380         }
 381         closedir(srcdir);
 382 }
 383
 384 void zebra_ns_notify_init(void)
 385 {
 386         int fd_monitor;
 387
 388         fd_monitor = inotify_init();
 389         if (fd_monitor < 0) {
 390                 flog_err_sys(
 391                         EC_LIB_SYSTEM_CALL,
 392                         "NS notify init: failed to initialize inotify (%s)",
 393                         safe_strerror(errno));
 394         }
 395         if (inotify_add_watch(fd_monitor, NS_RUN_DIR,
 396                               IN_CREATE | IN_DELETE) < 0) {
 397                 flog_err_sys(EC_LIB_SYSTEM_CALL,
 398                              "NS notify watch: failed to add watch (%s)",
 399                              safe_strerror(errno));
 400         }
 401         thread_add_read(zrouter.master, zebra_ns_notify_read, NULL, fd_monitor,
 402                         &zebra_netns_notify_current);
 403 }
 404
 405 void zebra_ns_notify_close(void)
 406 {
 407         if (zebra_netns_notify_current == NULL)
 408                 return;
 409
 410         int fd = 0;
 411
 412         if (zebra_netns_notify_current->u.fd > 0)
 413                 fd = zebra_netns_notify_current->u.fd;
 414
 415         if (zebra_netns_notify_current->master != NULL)
 416                 thread_cancel(&zebra_netns_notify_current);
 417
 418         /* auto-removal of notify items */
 419         if (fd > 0)
 420                 close(fd);
 421 }
 422
 423 #else
 424 void zebra_ns_notify_parse(void)
 425 {
 426 }
 427
 428 void zebra_ns_notify_init(void)
 429 {
 430 }
 431
 432 void zebra_ns_notify_close(void)
 433 {
 434 }
 435 #endif /* !HAVE_NETLINK */