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
  38 #include "zserv.h"
  39 #include "zebra_memory.h"
  40 #endif /* defined(HAVE_NETLINK) */
  41
  42 #include "zebra_netns_notify.h"
  43 #include "zebra_netns_id.h"
  44
  45 #ifdef HAVE_NETLINK
  46
  47 /* upon creation of folder under /var/run/netns,
  48  * wait that netns context is bound to
  49  * that folder 10 seconds
  50  */
  51 #define ZEBRA_NS_POLLING_INTERVAL_MSEC     1000
  52 #define ZEBRA_NS_POLLING_MAX_RETRIES  200
  53
  54 DEFINE_MTYPE_STATIC(ZEBRA, NETNS_MISC, "ZebraNetNSInfo")
  55 static struct thread *zebra_netns_notify_current;
  56
  57 struct zebra_netns_info {
  58         const char *netnspath;
  59         unsigned int retries;
  60 };
  61
  62 static int zebra_ns_ready_read(struct thread *t);
  63 static void zebra_ns_notify_create_context_from_entry_name(const char *name);
  64 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
  65                                   int stop_retry);
  66 static int zebra_ns_notify_read(struct thread *t);
  67
  68 static void zebra_ns_notify_create_context_from_entry_name(const char *name)
  69 {
  70         char *netnspath = ns_netns_pathname(NULL, name);
  71         struct vrf *vrf;
  72         int ret;
  73         ns_id_t ns_id, ns_id_external;
  74
  75         if (netnspath == NULL)
  76                 return;
  77
  78         if (zserv_privs.change(ZPRIVS_RAISE))
  79                 zlog_err("Can't raise privileges");
  80         ns_id = zebra_ns_id_get(netnspath);
  81         if (zserv_privs.change(ZPRIVS_LOWER))
  82                 zlog_err("Can't lower privileges");
  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_warn(
  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                 zlog_warn("NS notify : failed to create VRF %s", name);
  96                 ns_map_nsid_with_external(ns_id, false);
  97                 return;
  98         }
  99         if (zserv_privs.change(ZPRIVS_RAISE))
 100                 zlog_err("Can't raise privileges");
 101         ret = vrf_netns_handler_create(NULL, vrf, netnspath,
 102                                        ns_id_external, ns_id);
 103         if (zserv_privs.change(ZPRIVS_LOWER))
 104                 zlog_err("Can't lower privileges");
 105         if (ret != CMD_SUCCESS) {
 106                 zlog_warn("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                 zlog_warn(
 137                         "NS notify : no VRF found using NS %s",
 138                         name);
 139                 return 0;
 140         }
 141         /* Clear configured flag and invoke delete. */
 142         UNSET_FLAG(vrf->status, VRF_CONFIGURED);
 143         ns = (struct ns *)vrf->ns_ctxt;
 144         /* the deletion order is the same
 145          * as the one used when siging signal is received
 146          */
 147         vrf_delete(vrf);
 148         if (ns)
 149                 ns_delete(ns);
 150
 151         zlog_info("NS notify : deleted VRF %s", name);
 152         return 0;
 153 }
 154
 155
 156 static int zebra_ns_ready_read(struct thread *t)
 157 {
 158         struct zebra_netns_info *zns_info = THREAD_ARG(t);
 159         const char *netnspath;
 160         int err, stop_retry = 0;
 161
 162         if (!zns_info)
 163                 return 0;
 164         if (!zns_info->netnspath) {
 165                 XFREE(MTYPE_NETNS_MISC, zns_info);
 166                 return 0;
 167         }
 168         netnspath = zns_info->netnspath;
 169         if (--zns_info->retries == 0)
 170                 stop_retry = 1;
 171         if (zserv_privs.change(ZPRIVS_RAISE))
 172                 zlog_err("Can't raise privileges");
 173         err = ns_switch_to_netns(netnspath);
 174         if (zserv_privs.change(ZPRIVS_LOWER))
 175                 zlog_err("Can't lower privileges");
 176         if (err < 0)
 177                 return zebra_ns_continue_read(zns_info, stop_retry);
 178
 179         /* go back to default ns */
 180         if (zserv_privs.change(ZPRIVS_RAISE))
 181                 zlog_err("Can't raise privileges");
 182         err = ns_switchback_to_initial();
 183         if (zserv_privs.change(ZPRIVS_LOWER))
 184                 zlog_err("Can't lower privileges");
 185         if (err < 0)
 186                 return zebra_ns_continue_read(zns_info, stop_retry);
 187
 188         /* success : close fd and create zns context */
 189         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 190         return zebra_ns_continue_read(zns_info, 1);
 191 }
 192
 193 static int zebra_ns_notify_read(struct thread *t)
 194 {
 195         int fd_monitor = THREAD_FD(t);
 196         struct inotify_event *event;
 197         char buf[BUFSIZ];
 198         ssize_t len;
 199
 200         zebra_netns_notify_current = thread_add_read(
 201                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 202         len = read(fd_monitor, buf, sizeof(buf));
 203         if (len < 0) {
 204                 zlog_warn("NS notify read: failed to read (%s)",
 205                           safe_strerror(errno));
 206                 return 0;
 207         }
 208         for (event = (struct inotify_event *)buf; (char *)event < &buf[len];
 209              event = (struct inotify_event *)((char *)event + sizeof(*event)
 210                                               + event->len)) {
 211                 char *netnspath;
 212                 struct zebra_netns_info *netnsinfo;
 213
 214                 if (!(event->mask & (IN_CREATE | IN_DELETE)))
 215                         continue;
 216                 if (event->mask & IN_DELETE)
 217                         return zebra_ns_delete(event->name);
 218
 219                 if (offsetof(struct inotify_event, name) + event->len
 220                     >= sizeof(buf)) {
 221                         zlog_err("NS notify read: buffer underflow");
 222                         break;
 223                 }
 224
 225                 if (strnlen(event->name, event->len) == event->len) {
 226                         zlog_err("NS notify error: bad event name");
 227                         break;
 228                 }
 229
 230                 netnspath = ns_netns_pathname(NULL, event->name);
 231                 if (!netnspath)
 232                         continue;
 233                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 234                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 235                                     sizeof(struct zebra_netns_info));
 236                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 237                 netnsinfo->netnspath = netnspath;
 238                 thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 239                                       (void *)netnsinfo, 0, NULL);
 240         }
 241         return 0;
 242 }
 243
 244 void zebra_ns_notify_parse(void)
 245 {
 246         struct dirent *dent;
 247         DIR *srcdir = opendir(NS_RUN_DIR);
 248
 249         if (srcdir == NULL) {
 250                 zlog_warn("NS parsing init: failed to parse %s", NS_RUN_DIR);
 251                 return;
 252         }
 253         while ((dent = readdir(srcdir)) != NULL) {
 254                 struct stat st;
 255
 256                 if (strcmp(dent->d_name, ".") == 0
 257                     || strcmp(dent->d_name, "..") == 0)
 258                         continue;
 259                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 260                         zlog_warn("NS parsing init: failed to parse entry %s",
 261                                   dent->d_name);
 262                         continue;
 263                 }
 264                 if (S_ISDIR(st.st_mode)) {
 265                         zlog_warn("NS parsing init: %s is not a NS",
 266                                   dent->d_name);
 267                         continue;
 268                 }
 269                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 270         }
 271         closedir(srcdir);
 272 }
 273
 274 void zebra_ns_notify_init(void)
 275 {
 276         int fd_monitor;
 277
 278         zebra_netns_notify_current = NULL;
 279         fd_monitor = inotify_init();
 280         if (fd_monitor < 0) {
 281                 zlog_warn("NS notify init: failed to initialize inotify (%s)",
 282                           safe_strerror(errno));
 283         }
 284         if (inotify_add_watch(fd_monitor, NS_RUN_DIR,
 285                               IN_CREATE | IN_DELETE) < 0) {
 286                 zlog_warn("NS notify watch: failed to add watch (%s)",
 287                           safe_strerror(errno));
 288         }
 289         zebra_netns_notify_current = thread_add_read(
 290                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 291 }
 292
 293 void zebra_ns_notify_close(void)
 294 {
 295         if (zebra_netns_notify_current == NULL)
 296                 return;
 297
 298         int fd = 0;
 299
 300         if (zebra_netns_notify_current->u.fd > 0)
 301                 fd = zebra_netns_notify_current->u.fd;
 302         thread_cancel(zebra_netns_notify_current);
 303         /* auto-removal of inotify items */
 304         if (fd > 0)
 305                 close(fd);
 306 }
 307
 308 #else
 309 void zebra_ns_notify_parse(void)
 310 {
 311 }
 312
 313 void zebra_ns_notify_init(void)
 314 {
 315 }
 316
 317 void zebra_ns_notify_close(void)
 318 {
 319 }
 320 #endif /* !HAVE_NETLINK */