ospfd, vtysh: Add support for Route tags

[Forward ported by Cumulus]

Credit
------
A huge amount of credit for this patch goes to Piotr Chytla for
their 'route tags support' patch that was submitted to quagga-dev
in June 2007.

Documentation
-------------
All ipv4 and ipv6 static route commands now have a "tag" option
which allows the user to set a tag between 1 and 65535.

quagga(config)# ip route 1.1.1.1/32 10.1.1.1 tag ?
 <1-65535>  Tag value
quagga(config)# ip route 1.1.1.1/32 10.1.1.1 tag 40
quagga(config)#

quagga# show ip route 1.1.1.1/32
Routing entry for 1.1.1.1/32
  Known via "static", distance 1, metric 0, tag 40, best
  * 10.1.1.1, via swp1

quagga#

The route-map parser supports matching on tags and setting tags
!
route-map MATCH_TAG_18 permit 10
 match tag 18
!

!
route-map SET_TAG_22 permit 10
 set tag 22
!

BGP and OSPF support:
- matching on tags when redistribing routes from the RIB into BGP/OSPF.
- setting tags when redistribing routes from the RIB into BGP/OSPF.

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>
Signed-off-by: Piotr Chytla <pch@packetconsulting.pl>
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/ospfd/ospfd.h b/ospfd/ospfd.h
index 508f623..4181d11 100644
--- a/ospfd/ospfd.h
+++ b/ospfd/ospfd.h
@@ -238,6 +238,9 @@
 				   -1 means metric value is not set. */
   } dmetric [ZEBRA_ROUTE_MAX + 1];
 
+  /* Redistribute tag info. */
+  u_short dtag [ZEBRA_ROUTE_MAX + 1];
+
   /* For redistribute route map. */
   struct
   {