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 (vrf_handler_create(NULL, name, &vrf) != CMD_SUCCESS) {
  79                 zlog_warn("NS notify : failed to create VRF %s", name);
  80                 return;
  81         }
  82         if (zserv_privs.change(ZPRIVS_RAISE))
  83                 zlog_err("Can't raise privileges");
  84         ns_id = zebra_ns_id_get(netnspath);
  85         if (zserv_privs.change(ZPRIVS_LOWER))
  86                 zlog_err("Can't lower privileges");
  87         ret = vrf_netns_handler_create(NULL, vrf, netnspath, ns_id);
  88         if (ret != CMD_SUCCESS) {
  89                 zlog_warn("NS notify : failed to create NS %s", netnspath);
  90                 return;
  91         }
  92         zlog_info("NS notify : created VRF %s NS %s",
  93                    name, netnspath);
  94 }
  95
  96 static int zebra_ns_continue_read(struct zebra_netns_info *zns_info,
  97                                   int stop_retry)
  98 {
  99         void *ns_path_ptr = (void *)zns_info->netnspath;
 100
 101         if (stop_retry) {
 102                 XFREE(MTYPE_NETNS_MISC, ns_path_ptr);
 103                 XFREE(MTYPE_NETNS_MISC, zns_info);
 104                 return 0;
 105         }
 106         thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 107                               (void *)zns_info,
 108                               ZEBRA_NS_POLLING_INTERVAL_MSEC, NULL);
 109         return 0;
 110 }
 111
 112 static int zebra_ns_ready_read(struct thread *t)
 113 {
 114         struct zebra_netns_info *zns_info = THREAD_ARG(t);
 115         const char *netnspath;
 116         int err, stop_retry = 0;
 117
 118         if (!zns_info)
 119                 return 0;
 120         if (!zns_info->netnspath) {
 121                 XFREE(MTYPE_NETNS_MISC, zns_info);
 122                 return 0;
 123         }
 124         netnspath = zns_info->netnspath;
 125         if (--zns_info->retries == 0)
 126                 stop_retry = 1;
 127         if (zserv_privs.change(ZPRIVS_RAISE))
 128                 zlog_err("Can't raise privileges");
 129         err = ns_switch_to_netns(netnspath);
 130         if (zserv_privs.change(ZPRIVS_LOWER))
 131                 zlog_err("Can't lower privileges");
 132         if (err < 0)
 133                 return zebra_ns_continue_read(zns_info, stop_retry);
 134
 135         /* go back to default ns */
 136         if (zserv_privs.change(ZPRIVS_RAISE))
 137                 zlog_err("Can't raise privileges");
 138         err = ns_switchback_to_initial();
 139         if (zserv_privs.change(ZPRIVS_LOWER))
 140                 zlog_err("Can't lower privileges");
 141         if (err < 0)
 142                 return zebra_ns_continue_read(zns_info, stop_retry);
 143
 144         /* success : close fd and create zns context */
 145         zebra_ns_notify_create_context_from_entry_name(basename(netnspath));
 146         return zebra_ns_continue_read(zns_info, 1);
 147 }
 148
 149 static int zebra_ns_notify_read(struct thread *t)
 150 {
 151         int fd_monitor = THREAD_FD(t);
 152         struct inotify_event *event;
 153         char buf[BUFSIZ];
 154         ssize_t len;
 155
 156         zebra_netns_notify_current = thread_add_read(zebrad.master,
 157                                                      zebra_ns_notify_read,
 158                                                      NULL, fd_monitor, NULL);
 159         len = read(fd_monitor, buf, sizeof(buf));
 160         if (len < 0) {
 161                 zlog_warn("NS notify read: failed to read (%s)",
 162                           safe_strerror(errno));
 163                 return 0;
 164         }
 165         for (event = (struct inotify_event *)buf;
 166              (char *)event < &buf[len];
 167              event = (struct inotify_event *)((char *)event +
 168                                               sizeof(*event) + event->len)) {
 169                 char *netnspath;
 170                 struct zebra_netns_info *netnsinfo;
 171
 172                 if (!(event->mask & IN_CREATE))
 173                         continue;
 174                 netnspath = ns_netns_pathname(NULL, event->name);
 175                 if (!netnspath)
 176                         continue;
 177                 netnspath = XSTRDUP(MTYPE_NETNS_MISC, netnspath);
 178                 netnsinfo = XCALLOC(MTYPE_NETNS_MISC,
 179                                     sizeof(struct zebra_netns_info));
 180                 netnsinfo->retries = ZEBRA_NS_POLLING_MAX_RETRIES;
 181                 netnsinfo->netnspath = netnspath;
 182                 thread_add_timer_msec(zebrad.master, zebra_ns_ready_read,
 183                                        (void *)netnsinfo, 0, NULL);
 184         }
 185         return 0;
 186 }
 187
 188 void zebra_ns_notify_parse(void)
 189 {
 190         struct dirent *dent;
 191         DIR *srcdir = opendir(NS_RUN_DIR);
 192
 193         if (srcdir == NULL) {
 194                 zlog_warn("NS parsing init: failed to parse %s", NS_RUN_DIR);
 195                 return;
 196         }
 197         while ((dent = readdir(srcdir)) != NULL) {
 198                 struct stat st;
 199
 200                 if (strcmp(dent->d_name, ".") == 0
 201                    || strcmp(dent->d_name, "..") == 0)
 202                         continue;
 203                 if (fstatat(dirfd(srcdir), dent->d_name, &st, 0) < 0) {
 204                         zlog_warn("NS parsing init: failed to parse entry %s",
 205                                   dent->d_name);
 206                         continue;
 207                 }
 208                 if (S_ISDIR(st.st_mode)) {
 209                         zlog_warn("NS parsing init: %s is not a NS",
 210                                   dent->d_name);
 211                         continue;
 212                 }
 213                 zebra_ns_notify_create_context_from_entry_name(dent->d_name);
 214         }
 215         closedir(srcdir);
 216 }
 217
 218 void zebra_ns_notify_init(void)
 219 {
 220         int fd_monitor;
 221
 222         zebra_netns_notify_current = NULL;
 223         fd_monitor = inotify_init();
 224         if (fd_monitor < 0) {
 225                 zlog_warn("NS notify init: failed to initialize inotify (%s)",
 226                           safe_strerror(errno));
 227         }
 228         if (inotify_add_watch(fd_monitor, NS_RUN_DIR, IN_CREATE) < 0) {
 229                 zlog_warn("NS notify watch: failed to add watch (%s)",
 230                           safe_strerror(errno));
 231         }
 232         zebra_netns_notify_current = thread_add_read(zebrad.master,
 233                                                      zebra_ns_notify_read,
 234                                                      NULL, fd_monitor, NULL);
 235 }
 236
 237 void zebra_ns_notify_close(void)
 238 {
 239         if (zebra_netns_notify_current == NULL)
 240                 return;
 241
 242         int fd = 0;
 243
 244         if (zebra_netns_notify_current->u.fd > 0)
 245                 fd = zebra_netns_notify_current->u.fd;
 246         thread_cancel(zebra_netns_notify_current);
 247         /* auto-removal of inotify items */
 248         if (fd > 0)
 249                 close(fd);
 250 }
 251
 252 #else
 253 void zebra_ns_notify_parse(void)
 254 {
 255 }
 256
 257 void zebra_ns_notify_init(void)
 258 {
 259 }
 260
 261 void zebra_ns_notify_close(void)
 262 {
 263 }
 264 #endif /* !HAVE_NETLINK */