lib, vtysh: support multiple VRFs by using linux netns

We realize VRFs with linux netns by default. The main job is
to associate a VRF with a netns. Currently this is done by
the configuration:

  [no] vrf N netns <netns-name>

This command is also available in vtysh and goes to only
zebra, because presently only zebra supports multiple VRF.

A file descriptor is added to "struct vrf". This is for the
associated netns file. Once the command "vrf N netns NAME"
is executed, the specified file is opened and the file
descriptor is stored in the VRF N. In this way the
association is formed.

In vrf_socket(), we first switch to the specified VRF by
using the stored file descriptor, and then can allocate
a socket which is working in the associated netns.

Signed-off-by: Feng Lu <lu.feng@6wind.com>
Reviewed-by: Alain Ritoux <alain.ritoux@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
(cherry picked from commit 55cfa2f190620f7c711944637659bc208970324d)

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/ns.h b/lib/ns.h
index 81e24562c..3fac73986 100644
--- a/lib/ns.h
+++ b/lib/ns.h
@@ -33,7 +33,7 @@ typedef u_int16_t ns_id_t;
 /*
  * The command strings
  */
-
+#define NS_RUN_DIR         "/var/run/netns"
 #define NS_CMD_STR         "logical-router <0-65535>"
 #define NS_CMD_HELP_STR    "Specify the Logical-Router\nThe Logical-Router ID\n"