MPLS subsystem

The MPLS subsystem manages MPLS labels and handles their allocation to
MPLS-aware routing protocols. These labels are then attached to IP or VPN
routes representing label switched paths -- LSPs.

There was already a preliminary MPLS support consisting of MPLS label
net_addr, MPLS routing tables with static MPLS routes, remote labels in
next hops, and kernel protocol support.

This patch adds the MPLS domain as a basic structure representing local
label space with dynamic label allocator and configurable label ranges.
To represent LSPs, allocated local labels can be attached as route
attributes to IP or VPN routes with local labels as attributes.

There are several steps for handling LSP routes in routing protocols --
deciding to which forwarding equivalence class (FEC) the LSP route
belongs, allocating labels for new FECs, announcing MPLS routes for new
FECs, attaching labels to LSP routes. The FEC map structure implements
basic code for managing FECs in routing protocols, therefore existing
protocols can be made MPLS-aware by adding FEC map and delegating
most work related to local label management to it.

1 files changed, 20 insertions, 6 deletions

diff --git a/nest/rt-attr.c b/nest/rt-attr.c
index 9e29abc8..367a08ef 100644
--- a/nest/rt-attr.c
+++ b/nest/rt-attr.c
@@ -803,13 +803,27 @@ ea_free(ea_list *o)
 static int
 get_generic_attr(const eattr *a, byte **buf, int buflen UNUSED)
 {
-  if (a->id == EA_GEN_IGP_METRIC)
-    {
-      *buf += bsprintf(*buf, "igp_metric");
-      return GA_NAME;
-    }
+  switch (a->id)
+  {
+  case EA_GEN_IGP_METRIC:
+    *buf += bsprintf(*buf, "igp_metric");
+    return GA_NAME;
+
+  case EA_MPLS_LABEL:
+    *buf += bsprintf(*buf, "mpls_label");
+    return GA_NAME;
 
-  return GA_UNKNOWN;
+  case EA_MPLS_POLICY:
+    *buf += bsprintf(*buf, "mpls_policy");
+    return GA_NAME;
+
+  case EA_MPLS_CLASS:
+    *buf += bsprintf(*buf, "mpls_class");
+    return GA_NAME;
+
+  default:
+    return GA_UNKNOWN;
+  }
 }
 
 void