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
  46 #ifdef HAVE_NETLINK
  47
  48 /* upon creation of folder under /var/run/netns,
  49  * wait that netns context is bound to
  50  * that folder 10 seconds
  51  */
  52 #define ZEBRA_NS_POLLING_INTERVAL_MSEC     1000
  53 #define ZEBRA_NS_POLLING_MAX_RETRIES  200
  54
  55 DEFINE_MTYPE_STATIC(ZEBRA, NETNS_MISC, "ZebraNetNSInfo")
  56 static struct thread *zebra_netns_notify_current;
  57
  58 struct zebra_netns_info {
  59         const char *netnspath;
  60         unsigned int retries;
  61 };
  62
  63 static int zebra_ns_ready_read(struct thread *t);
  64 static void zebra_ns_notify_create_context_from_entry_name(const char *name);
  65 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
  66                                   int stop_retry);
  67 static int zebra_ns_notify_read(struct thread *t);
  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;
  75
  76         if (netnspath == NULL)
  77                 return;
  78
  79         frr_elevate_privs(&zserv_privs) {
  80                 ns_id = zebra_ns_id_get(netnspath);
  81         }
  82         if (ns_id == NS_UNKNOWN)
  83                 return;
  84         ns_id_external = ns_map_nsid_with_external(ns_id, true);
  85         /* if VRF with NS ID already present */
  86         vrf = vrf_lookup_by_id((vrf_id_t)ns_id_external);
  87         if (vrf) {
  88                 zlog_warn(
  89                         "NS notify : same NSID used by VRF %s. Ignore NS %s creation",
  90                         vrf->name, netnspath);
  91                 return;
  92         }
  93         if (vrf_handler_create(NULL, name, &vrf) != CMD_SUCCESS) {
  94                 zlog_warn("NS notify : failed to create VRF %s", name);
  95                 ns_map_nsid_with_external(ns_id, false);
  96                 return;
  97         }
  98         frr_elevate_privs(&zserv_privs) {
  99                 ret = vrf_netns_handler_create(NULL, vrf, netnspath,
 100                                                ns_id_external, ns_id);
 101         }
 102         if (ret != CMD_SUCCESS) {
 103                 zlog_warn("NS notify : failed to create NS %s", netnspath);
 104                 ns_map_nsid_with_external(ns_id, false);
 105                 vrf_delete(vrf);
 106                 return;
 107         }
 108         zlog_info("NS notify : created VRF %s NS %s", name, netnspath);
 109 }
 110
 111 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
 112                                   int stop_retry)
 113 {
 114         void *ns_path_ptr = (void *)zns_info->netnspath;
 115
 116         if (stop_retry) {
 117                 XFREE(MTYPE_NETNS_MISC, ns_path_ptr);
 118                 XFREE(MTYPE_NETNS_MISC, zns_info);
 119                 return 0;
 120         }
 121         thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 122                               (void *)zns_info, ZEBRA_NS_POLLING_INTERVAL_MSEC,
 123                               NULL);
 124         return 0;
 125 }
 126
 127 static int zebra_ns_delete(char *name)
 128 {
 129         struct vrf *vrf = vrf_lookup_by_name(name);
 130         struct ns *ns;
 131
 132         if (!vrf) {
 133                 zlog_warn(
 134                         "NS notify : no VRF found using NS %s",
 135                         name);
 136                 return 0;
 137         }
 138         /* Clear configured flag and invoke delete. */
 139         UNSET_FLAG(vrf->status, VRF_CONFIGURED);
 140         ns = (struct ns *)vrf->ns_ctxt;
 141         /* the deletion order is the same
 142          * as the one used when siging signal is received
 143          */
 144         vrf_delete(vrf);
 145         if (ns)
 146                 ns_delete(ns);
 147
 148         zlog_info("NS notify : deleted VRF %s", name);
 149         return 0;
 150 }
 151
 152
 153 static int zebra_ns_ready_read(struct thread *t)
 154 {
 155         struct zebra_netns_info *zns_info = THREAD_ARG(t);
 156         const char *netnspath;
 157         int err, stop_retry = 0;
 158
 159         if (!zns_info)
 160                 return 0;
 161         if (!zns_info->netnspath) {
 162                 XFREE(MTYPE_NETNS_MISC, zns_info);
 163                 return 0;
 164         }
 165         netnspath = zns_info->netnspath;
 166         if (--zns_info->retries == 0)
 167                 stop_retry = 1;
 168         frr_elevate_privs(&zserv_privs) {
 169                 err = ns_switch_to_netns(netnspath);
 170         }
 171         if (err < 0)
 172                 return zebra_ns_continue_read(zns_info, stop_retry);
 173
 174         /* go back to default ns */
 175         frr_elevate_privs(&zserv_privs) {
 176                 err = ns_switchback_to_initial();
 177         }
 178         if (err < 0)
 179                 return zebra_ns_continue_read(zns_info, stop_retry);
 180
 181         /* success : close fd and create zns context */
 182         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 183         return zebra_ns_continue_read(zns_info, 1);
 184 }
 185
 186 static int zebra_ns_notify_read(struct thread *t)
 187 {
 188         int fd_monitor = THREAD_FD(t);
 189         struct inotify_event *event;
 190         char buf[BUFSIZ];
 191         ssize_t len;
 192
 193         zebra_netns_notify_current = thread_add_read(
 194                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 195         len = read(fd_monitor, buf, sizeof(buf));
 196         if (len < 0) {
 197                 zlog_warn("NS notify read: failed to read (%s)",
 198                           safe_strerror(errno));
 199                 return 0;
 200         }
 201         for (event = (struct inotify_event *)buf; (char *)event < &buf[len];
 202              event = (struct inotify_event *)((char *)event + sizeof(*event)
 203                                               + event->len)) {
 204                 char *netnspath;
 205                 struct zebra_netns_info *netnsinfo;
 206
 207                 if (!(event->mask & (IN_CREATE | IN_DELETE)))
 208                         continue;
 209                 if (event->mask & IN_DELETE)
 210                         return zebra_ns_delete(event->name);
 211
 212                 if (offsetof(struct inotify_event, name) + event->len
 213                     >= sizeof(buf)) {
 214                         zlog_err("NS notify read: buffer underflow");
 215                         break;
 216                 }
 217
 218                 if (strnlen(event->name, event->len) == event->len) {
 219                         zlog_err("NS notify error: bad event name");
 220                         break;
 221                 }
 222
 223                 netnspath = ns_netns_pathname(NULL, event->name);
 224                 if (!netnspath)
 225                         continue;
 226                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 227                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 228                                     sizeof(struct zebra_netns_info));
 229                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 230                 netnsinfo->netnspath = netnspath;
 231                 thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 232                                       (void *)netnsinfo, 0, NULL);
 233         }
 234         return 0;
 235 }
 236
 237 void zebra_ns_notify_parse(void)
 238 {
 239         struct dirent *dent;
 240         DIR *srcdir = opendir(NS_RUN_DIR);
 241
 242         if (srcdir == NULL) {
 243                 zlog_warn("NS parsing init: failed to parse %s", NS_RUN_DIR);
 244                 return;
 245         }
 246         while ((dent = readdir(srcdir)) != NULL) {
 247                 struct stat st;
 248
 249                 if (strcmp(dent->d_name, ".") == 0
 250                     || strcmp(dent->d_name, "..") == 0)
 251                         continue;
 252                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 253                         zlog_warn("NS parsing init: failed to parse entry %s",
 254                                   dent->d_name);
 255                         continue;
 256                 }
 257                 if (S_ISDIR(st.st_mode)) {
 258                         zlog_warn("NS parsing init: %s is not a NS",
 259                                   dent->d_name);
 260                         continue;
 261                 }
 262                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 263         }
 264         closedir(srcdir);
 265 }
 266
 267 void zebra_ns_notify_init(void)
 268 {
 269         int fd_monitor;
 270
 271         zebra_netns_notify_current = NULL;
 272         fd_monitor = inotify_init();
 273         if (fd_monitor < 0) {
 274                 zlog_warn("NS notify init: failed to initialize inotify (%s)",
 275                           safe_strerror(errno));
 276         }
 277         if (inotify_add_watch(fd_monitor, NS_RUN_DIR,
 278                               IN_CREATE | IN_DELETE) < 0) {
 279                 zlog_warn("NS notify watch: failed to add watch (%s)",
 280                           safe_strerror(errno));
 281         }
 282         zebra_netns_notify_current = thread_add_read(
 283                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 284 }
 285
 286 void zebra_ns_notify_close(void)
 287 {
 288         if (zebra_netns_notify_current == NULL)
 289                 return;
 290
 291         int fd = 0;
 292
 293         if (zebra_netns_notify_current->u.fd > 0)
 294                 fd = zebra_netns_notify_current->u.fd;
 295         thread_cancel(zebra_netns_notify_current);
 296         /* auto-removal of inotify items */
 297         if (fd > 0)
 298                 close(fd);
 299 }
 300
 301 #else
 302 void zebra_ns_notify_parse(void)
 303 {
 304 }
 305
 306 void zebra_ns_notify_init(void)
 307 {
 308 }
 309
 310 void zebra_ns_notify_close(void)
 311 {
 312 }
 313 #endif /* !HAVE_NETLINK */