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;
  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 VRF with NS ID already present */
  84         vrf = vrf_lookup_by_id((vrf_id_t)ns_id);
  85         if (vrf) {
  86                 zlog_warn(
  87                         "NS notify : same NSID used by VRF %s. Ignore NS %s creation",
  88                         vrf->name, netnspath);
  89                 return;
  90         }
  91         if (vrf_handler_create(NULL, name, &vrf) != CMD_SUCCESS) {
  92                 zlog_warn("NS notify : failed to create VRF %s", name);
  93                 return;
  94         }
  95         ret = vrf_netns_handler_create(NULL, vrf, netnspath, ns_id);
  96         if (ret != CMD_SUCCESS) {
  97                 zlog_warn("NS notify : failed to create NS %s", netnspath);
  98                 return;
  99         }
 100         zlog_info("NS notify : created VRF %s NS %s", name, netnspath);
 101 }
 102
 103 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
 104                                   int stop_retry)
 105 {
 106         void *ns_path_ptr = (void *)zns_info->netnspath;
 107
 108         if (stop_retry) {
 109                 XFREE(MTYPE_NETNS_MISC, ns_path_ptr);
 110                 XFREE(MTYPE_NETNS_MISC, zns_info);
 111                 return 0;
 112         }
 113         thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 114                               (void *)zns_info, ZEBRA_NS_POLLING_INTERVAL_MSEC,
 115                               NULL);
 116         return 0;
 117 }
 118
 119 static int zebra_ns_ready_read(struct thread *t)
 120 {
 121         struct zebra_netns_info *zns_info = THREAD_ARG(t);
 122         const char *netnspath;
 123         int err, stop_retry = 0;
 124
 125         if (!zns_info)
 126                 return 0;
 127         if (!zns_info->netnspath) {
 128                 XFREE(MTYPE_NETNS_MISC, zns_info);
 129                 return 0;
 130         }
 131         netnspath = zns_info->netnspath;
 132         if (--zns_info->retries == 0)
 133                 stop_retry = 1;
 134         if (zserv_privs.change(ZPRIVS_RAISE))
 135                 zlog_err("Can't raise privileges");
 136         err = ns_switch_to_netns(netnspath);
 137         if (zserv_privs.change(ZPRIVS_LOWER))
 138                 zlog_err("Can't lower privileges");
 139         if (err < 0)
 140                 return zebra_ns_continue_read(zns_info, stop_retry);
 141
 142         /* go back to default ns */
 143         if (zserv_privs.change(ZPRIVS_RAISE))
 144                 zlog_err("Can't raise privileges");
 145         err = ns_switchback_to_initial();
 146         if (zserv_privs.change(ZPRIVS_LOWER))
 147                 zlog_err("Can't lower privileges");
 148         if (err < 0)
 149                 return zebra_ns_continue_read(zns_info, stop_retry);
 150
 151         /* success : close fd and create zns context */
 152         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 153         return zebra_ns_continue_read(zns_info, 1);
 154 }
 155
 156 static int zebra_ns_notify_read(struct thread *t)
 157 {
 158         int fd_monitor = THREAD_FD(t);
 159         struct inotify_event *event;
 160         char buf[BUFSIZ];
 161         ssize_t len;
 162
 163         zebra_netns_notify_current = thread_add_read(
 164                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 165         len = read(fd_monitor, buf, sizeof(buf));
 166         if (len < 0) {
 167                 zlog_warn("NS notify read: failed to read (%s)",
 168                           safe_strerror(errno));
 169                 return 0;
 170         }
 171         for (event = (struct inotify_event *)buf; (char *)event < &buf[len];
 172              event = (struct inotify_event *)((char *)event + sizeof(*event)
 173                                               + event->len)) {
 174                 char *netnspath;
 175                 struct zebra_netns_info *netnsinfo;
 176
 177                 if (!(event->mask & IN_CREATE))
 178                         continue;
 179                 netnspath = ns_netns_pathname(NULL, event->name);
 180                 if (!netnspath)
 181                         continue;
 182                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 183                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 184                                     sizeof(struct zebra_netns_info));
 185                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 186                 netnsinfo->netnspath = netnspath;
 187                 thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 188                                       (void *)netnsinfo, 0, NULL);
 189         }
 190         return 0;
 191 }
 192
 193 void zebra_ns_notify_parse(void)
 194 {
 195         struct dirent *dent;
 196         DIR *srcdir = opendir(NS_RUN_DIR);
 197
 198         if (srcdir == NULL) {
 199                 zlog_warn("NS parsing init: failed to parse %s", NS_RUN_DIR);
 200                 return;
 201         }
 202         while ((dent = readdir(srcdir)) != NULL) {
 203                 struct stat st;
 204
 205                 if (strcmp(dent->d_name, ".") == 0
 206                     || strcmp(dent->d_name, "..") == 0)
 207                         continue;
 208                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 209                         zlog_warn("NS parsing init: failed to parse entry %s",
 210                                   dent->d_name);
 211                         continue;
 212                 }
 213                 if (S_ISDIR(st.st_mode)) {
 214                         zlog_warn("NS parsing init: %s is not a NS",
 215                                   dent->d_name);
 216                         continue;
 217                 }
 218                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 219         }
 220         closedir(srcdir);
 221 }
 222
 223 void zebra_ns_notify_init(void)
 224 {
 225         int fd_monitor;
 226
 227         zebra_netns_notify_current = NULL;
 228         fd_monitor = inotify_init();
 229         if (fd_monitor < 0) {
 230                 zlog_warn("NS notify init: failed to initialize inotify (%s)",
 231                           safe_strerror(errno));
 232         }
 233         if (inotify_add_watch(fd_monitor, NS_RUN_DIR, IN_CREATE) < 0) {
 234                 zlog_warn("NS notify watch: failed to add watch (%s)",
 235                           safe_strerror(errno));
 236         }
 237         zebra_netns_notify_current = thread_add_read(
 238                 zebrad.master, zebra_ns_notify_read, NULL, fd_monitor, NULL);
 239 }
 240
 241 void zebra_ns_notify_close(void)
 242 {
 243         if (zebra_netns_notify_current == NULL)
 244                 return;
 245
 246         int fd = 0;
 247
 248         if (zebra_netns_notify_current->u.fd > 0)
 249                 fd = zebra_netns_notify_current->u.fd;
 250         thread_cancel(zebra_netns_notify_current);
 251         /* auto-removal of inotify items */
 252         if (fd > 0)
 253                 close(fd);
 254 }
 255
 256 #else
 257 void zebra_ns_notify_parse(void)
 258 {
 259 }
 260
 261 void zebra_ns_notify_init(void)
 262 {
 263 }
 264
 265 void zebra_ns_notify_close(void)
 266 {
 267 }
 268 #endif /* !HAVE_NETLINK */