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 "zserv.h"
  40 #include "zebra_memory.h"
  41 #endif /* defined(HAVE_NETLINK) */
  42
  43 #include "zebra_netns_notify.h"
  44 #include "zebra_netns_id.h"
  45 #include "zebra_errors.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 int 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 int zebra_ns_notify_read(struct thread *t);
  69
  70 static void zebra_ns_notify_create_context_from_entry_name(const char *name)
  71 {
  72         char *netnspath = ns_netns_pathname(NULL, name);
  73         struct vrf *vrf;
  74         int ret;
  75         ns_id_t ns_id, ns_id_external;
  76
  77         if (netnspath == NULL)
  78                 return;
  79
  80         frr_elevate_privs(&zserv_privs) {
  81                 ns_id = zebra_ns_id_get(netnspath);
  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         if (vrf_handler_create(NULL, name, &vrf) != CMD_SUCCESS) {
  95                 flog_warn(EC_ZEBRA_NS_VRF_CREATION_FAILED,
  96                           "NS notify : failed to create VRF %s", name);
  97                 ns_map_nsid_with_external(ns_id, false);
  98                 return;
  99         }
 100         frr_elevate_privs(&zserv_privs) {
 101                 ret = vrf_netns_handler_create(NULL, vrf, netnspath,
 102                                                ns_id_external, ns_id);
 103         }
 104         if (ret != CMD_SUCCESS) {
 105                 flog_warn(EC_ZEBRA_NS_VRF_CREATION_FAILED,
 106                           "NS notify : failed to create NS %s", netnspath);
 107                 ns_map_nsid_with_external(ns_id, false);
 108                 vrf_delete(vrf);
 109                 return;
 110         }
 111         zlog_info("NS notify : created VRF %s NS %s", name, netnspath);
 112 }
 113
 114 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
 115                                   int stop_retry)
 116 {
 117         void *ns_path_ptr = (void *)zns_info->netnspath;
 118
 119         if (stop_retry) {
 120                 XFREE(MTYPE_NETNS_MISC, ns_path_ptr);
 121                 XFREE(MTYPE_NETNS_MISC, zns_info);
 122                 return 0;
 123         }
 124         thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 125                               (void *)zns_info, ZEBRA_NS_POLLING_INTERVAL_MSEC,
 126                               NULL);
 127         return 0;
 128 }
 129
 130 static int zebra_ns_delete(char *name)
 131 {
 132         struct vrf *vrf = vrf_lookup_by_name(name);
 133         struct ns *ns;
 134
 135         if (!vrf) {
 136                 flog_warn(EC_ZEBRA_NS_DELETION_FAILED_NO_VRF,
 137                           "NS notify : no VRF found using NS %s", name);
 138                 return 0;
 139         }
 140         /* Clear configured flag and invoke delete. */
 141         UNSET_FLAG(vrf->status, VRF_CONFIGURED);
 142         ns = (struct ns *)vrf->ns_ctxt;
 143         /* the deletion order is the same
 144          * as the one used when siging signal is received
 145          */
 146         vrf_delete(vrf);
 147         if (ns)
 148                 ns_delete(ns);
 149
 150         zlog_info("NS notify : deleted VRF %s", name);
 151         return 0;
 152 }
 153
 154 static int zebra_ns_notify_self_identify(struct stat *netst)
 155 {
 156         char net_path[64];
 157         int netns;
 158
 159         sprintf(net_path, "/proc/self/ns/net");
 160         netns = open(net_path, O_RDONLY);
 161         if (netns < 0)
 162                 return -1;
 163         if (fstat(netns, netst) < 0) {
 164                 close(netns);
 165                 return -1;
 166         }
 167         close(netns);
 168         return 0;
 169 }
 170
 171 static bool zebra_ns_notify_is_default_netns(const char *name)
 172 {
 173         struct stat default_netns_stat;
 174         struct stat st;
 175         char netnspath[64];
 176
 177         if (zebra_ns_notify_self_identify(&default_netns_stat))
 178                 return false;
 179
 180         memset(&st, 0, sizeof(struct stat));
 181         snprintf(netnspath, 64, "%s/%s", NS_RUN_DIR, name);
 182         /* compare with local stat */
 183         if (stat(netnspath, &st) == 0 &&
 184             (st.st_dev == default_netns_stat.st_dev) &&
 185             (st.st_ino == default_netns_stat.st_ino))
 186                 return true;
 187         return false;
 188 }
 189
 190 static int zebra_ns_ready_read(struct thread *t)
 191 {
 192         struct zebra_netns_info *zns_info = THREAD_ARG(t);
 193         const char *netnspath;
 194         int err, stop_retry = 0;
 195
 196         if (!zns_info)
 197                 return 0;
 198         if (!zns_info->netnspath) {
 199                 XFREE(MTYPE_NETNS_MISC, zns_info);
 200                 return 0;
 201         }
 202         netnspath = zns_info->netnspath;
 203         if (--zns_info->retries == 0)
 204                 stop_retry = 1;
 205         frr_elevate_privs(&zserv_privs) {
 206                 err = ns_switch_to_netns(netnspath);
 207         }
 208         if (err < 0)
 209                 return zebra_ns_continue_read(zns_info, stop_retry);
 210
 211         /* go back to default ns */
 212         frr_elevate_privs(&zserv_privs) {
 213                 err = ns_switchback_to_initial();
 214         }
 215         if (err < 0)
 216                 return zebra_ns_continue_read(zns_info, stop_retry);
 217
 218         if (zebra_ns_notify_is_default_netns(basename(netnspath))) {
 219                 zlog_warn(
 220                           "NS notify : NS %s is default VRF."
 221                           " Updating VRF Name", basename(netnspath));
 222                 vrf_set_default_name(basename(netnspath), false);
 223                 return zebra_ns_continue_read(zns_info, 1);
 224         }
 225
 226         /* success : close fd and create zns context */
 227         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 228         return zebra_ns_continue_read(zns_info, 1);
 229 }
 230
 231 static int zebra_ns_notify_read(struct thread *t)
 232 {
 233         int fd_monitor = THREAD_FD(t);
 234         struct inotify_event *event;
 235         char buf[BUFSIZ];
 236         ssize_t len;
 237
 238         zebra_netns_notify_current = thread_add_read(
 239                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 240         len = read(fd_monitor, buf, sizeof(buf));
 241         if (len < 0) {
 242                 flog_err_sys(EC_ZEBRA_NS_NOTIFY_READ,
 243                              "NS notify read: failed to read (%s)",
 244                              safe_strerror(errno));
 245                 return 0;
 246         }
 247         for (event = (struct inotify_event *)buf; (char *)event < &buf[len];
 248              event = (struct inotify_event *)((char *)event + sizeof(*event)
 249                                               + event->len)) {
 250                 char *netnspath;
 251                 struct zebra_netns_info *netnsinfo;
 252
 253                 if (!(event->mask & (IN_CREATE | IN_DELETE)))
 254                         continue;
 255                 if (event->mask & IN_DELETE)
 256                         return zebra_ns_delete(event->name);
 257
 258                 if (offsetof(struct inotify_event, name) + event->len
 259                     >= sizeof(buf)) {
 260                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 261                                  "NS notify read: buffer underflow");
 262                         break;
 263                 }
 264
 265                 if (strnlen(event->name, event->len) == event->len) {
 266                         flog_err(EC_ZEBRA_NS_NOTIFY_READ,
 267                                  "NS notify error: bad event name");
 268                         break;
 269                 }
 270
 271                 netnspath = ns_netns_pathname(NULL, event->name);
 272                 if (!netnspath)
 273                         continue;
 274                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 275                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 276                                     sizeof(struct zebra_netns_info));
 277                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 278                 netnsinfo->netnspath = netnspath;
 279                 thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 280                                       (void *)netnsinfo, 0, NULL);
 281         }
 282         return 0;
 283 }
 284
 285 void zebra_ns_notify_parse(void)
 286 {
 287         struct dirent *dent;
 288         DIR *srcdir = opendir(NS_RUN_DIR);
 289
 290         if (srcdir == NULL) {
 291                 flog_err_sys(EC_LIB_SYSTEM_CALL,
 292                              "NS parsing init: failed to parse %s", NS_RUN_DIR);
 293                 return;
 294         }
 295         while ((dent = readdir(srcdir)) != NULL) {
 296                 struct stat st;
 297
 298                 if (strcmp(dent->d_name, ".") == 0
 299                     || strcmp(dent->d_name, "..") == 0)
 300                         continue;
 301                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 302                         flog_err_sys(
 303                                 EC_LIB_SYSTEM_CALL,
 304                                 "NS parsing init: failed to parse entry %s",
 305                                 dent->d_name);
 306                         continue;
 307                 }
 308                 if (S_ISDIR(st.st_mode)) {
 309                         zlog_debug("NS parsing init: %s is not a NS",
 310                                    dent->d_name);
 311                         continue;
 312                 }
 313                 if (zebra_ns_notify_is_default_netns(dent->d_name)) {
 314                         zlog_warn(
 315                                   "NS notify : NS %s is default VRF."
 316                                   " Updating VRF Name", dent->d_name);
 317                         vrf_set_default_name(dent->d_name, false);
 318                         continue;
 319                 }
 320                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 321         }
 322         closedir(srcdir);
 323 }
 324
 325 void zebra_ns_notify_init(void)
 326 {
 327         int fd_monitor;
 328
 329         zebra_netns_notify_current = NULL;
 330         fd_monitor = inotify_init();
 331         if (fd_monitor < 0) {
 332                 flog_err_sys(
 333                         EC_LIB_SYSTEM_CALL,
 334                         "NS notify init: failed to initialize inotify (%s)",
 335                         safe_strerror(errno));
 336         }
 337         if (inotify_add_watch(fd_monitor, NS_RUN_DIR,
 338                               IN_CREATE | IN_DELETE) < 0) {
 339                 flog_err_sys(EC_LIB_SYSTEM_CALL,
 340                              "NS notify watch: failed to add watch (%s)",
 341                              safe_strerror(errno));
 342         }
 343         zebra_netns_notify_current = thread_add_read(
 344                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 345 }
 346
 347 void zebra_ns_notify_close(void)
 348 {
 349         if (zebra_netns_notify_current == NULL)
 350                 return;
 351
 352         int fd = 0;
 353
 354         if (zebra_netns_notify_current->u.fd > 0)
 355                 fd = zebra_netns_notify_current->u.fd;
 356
 357         if (zebra_netns_notify_current->master != NULL)
 358                 thread_cancel(zebra_netns_notify_current);
 359
 360         /* auto-removal of notify items */
 361         if (fd > 0)
 362                 close(fd);
 363 }
 364
 365 #else
 366 void zebra_ns_notify_parse(void)
 367 {
 368 }
 369
 370 void zebra_ns_notify_init(void)
 371 {
 372 }
 373
 374 void zebra_ns_notify_close(void)
 375 {
 376 }
 377 #endif /* !HAVE_NETLINK */