lib, zebra: move "struct vrf" to be a lib module

Previously "struct vrf" is defined locally in zebra. Now it is moved
to be a lib module.

This is the first step to support multi-VRF in quagga. The
implementation is splitted into small patches for the purpose of
easy review.

* lib:
    "struct vrf" with basic members is defined in vrf.c. The member
    "void *info" is for user data.

    Some basic functions are defined in vrf.c for adding/deleting/
    looking up a VRF, scanning the VRF table and initializing the
    VRF module.

    The type "vrf_id_t" is defined specificly for VRF ID.

* zebra:
    The previous "struct vrf" is re-defined as "struct zebra_vrf";
    and previous "vrf" variables are renamed to "zvrf".

    The previous "struct vrf" related functions are removed from
    zbera_rib.c. New functions are defined to maintain the new
    "struct zebra_vrf".

    The names vrf_xxx are reserved for the functions in VRF module.
    So:
    - the previous vrf_table() are renamed to zebra_vrf_table();
    - the previous vrf_static_table() are renamed to
      zebra_vrf_static_table().

    The main logic is not changed.

    BTW: Add a statement to zebra_snmp.c telling that the SNMP is
         running only for the MIBs in the default VRF.

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>
Acked-by: Vincent JARDIN <vincent.jardin@6wind.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/zebra/redistribute.c b/zebra/redistribute.c
index 94330ae..8bf8ea8 100644
--- a/zebra/redistribute.c
+++ b/zebra/redistribute.c
@@ -30,6 +30,7 @@
 #include "zclient.h"
 #include "linklist.h"
 #include "log.h"
+#include "vrf.h"
 
 #include "zebra/rib.h"
 #include "zebra/zserv.h"
@@ -101,7 +102,7 @@
   p.family = AF_INET;
 
   /* Lookup table.  */
-  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
+  table = zebra_vrf_table (AFI_IP, SAFI_UNICAST, VRF_DEFAULT);
   if (table)
     {
       rn = route_node_lookup (table, (struct prefix *)&p);
@@ -121,7 +122,7 @@
   p6.family = AF_INET6;
 
   /* Lookup table.  */
-  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
+  table = zebra_vrf_table (AFI_IP6, SAFI_UNICAST, VRF_DEFAULT);
   if (table)
     {
       rn = route_node_lookup (table, (struct prefix *)&p6);
@@ -145,7 +146,7 @@
   struct route_table *table;
   struct route_node *rn;
 
-  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
+  table = zebra_vrf_table (AFI_IP, SAFI_UNICAST, VRF_DEFAULT);
   if (table)
     for (rn = route_top (table); rn; rn = route_next (rn))
       RNODE_FOREACH_RIB (rn, newrib)
@@ -156,7 +157,7 @@
 	  zsend_route_multipath (ZEBRA_IPV4_ROUTE_ADD, client, &rn->p, newrib);
   
 #ifdef HAVE_IPV6
-  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
+  table = zebra_vrf_table (AFI_IP6, SAFI_UNICAST, VRF_DEFAULT);
   if (table)
     for (rn = route_top (table); rn; rn = route_next (rn))
       RNODE_FOREACH_RIB (rn, newrib)