BIER disposition default route

Change-Id: I7196ad8bf6afaf356674789c05e23ac000bc038e
Signed-off-by: Neale Ranns <nranns@cisco.com>

4 files changed, 45 insertions, 8 deletions

diff --git a/src/vnet/bier/bier.api b/src/vnet/bier/bier.api
index f7a13e4705b..6f88732aba9 100644
--- a/src/vnet/bier/bier.api
+++ b/src/vnet/bier/bier.api
@@ -221,7 +221,8 @@ define bier_disp_table_details
 /** \brief BIER Disposition Entry Add / del
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request
-    @param bde_bp - The Bit-position value for the entry
+    @param bde_bp - The Bit-position value for the entry, i.e. the sender's
+                    Use 0 for the default (match any source) entry.
     @param bde_tbl_id - The BIER dispositiontable-id the route is added in
     @param bde_next_hop_sw_if_index - the nextop interface
     @param bde_is_add - Is this a route add or delete
diff --git a/src/vnet/bier/bier_api.c b/src/vnet/bier/bier_api.c
index 67c70462540..002ea0b051a 100644
--- a/src/vnet/bier/bier_api.c
+++ b/src/vnet/bier/bier_api.c
@@ -496,7 +496,10 @@ vl_api_bier_disp_entry_add_del_t_handler (vl_api_bier_disp_entry_add_del_t * mp)
     table_id = ntohl(mp->bde_tbl_id);
     bp = ntohs(mp->bde_bp);
 
-    if (0 == bp || bp > 0xffff)
+    /*
+     * BP=0 is the default route
+     */
+    if (bp > 0xffff)
     {
         rv = -1;
         goto done;
diff --git a/src/vnet/bier/bier_disp_lookup_node.c b/src/vnet/bier/bier_disp_lookup_node.c
index 15515f467ca..1e1ea99557f 100644
--- a/src/vnet/bier/bier_disp_lookup_node.c
+++ b/src/vnet/bier/bier_disp_lookup_node.c
@@ -63,6 +63,7 @@ bier_disp_lookup_inline (vlib_main_t * vm,
         while (n_left_from > 0 && n_left_to_next > 0)
         {
             const bier_hdr_t *hdr0;
+            bier_hdr_src_id_t src0;
             vlib_buffer_t * b0;
             u32 bdei0, bdti0;
             u32 next0, bi0;
@@ -82,15 +83,22 @@ bier_disp_lookup_inline (vlib_main_t * vm,
             /*
              * lookup - source is in network order.
              */
-            bdei0 = bier_disp_table_lookup(bdti0, bier_hdr_get_src_id(hdr0));
+            src0 = bier_hdr_get_src_id(hdr0);
+            next0 = BIER_DISP_LOOKUP_NEXT_DISPATCH;
+
+            bdei0 = bier_disp_table_lookup(bdti0, src0);
 
             if (PREDICT_FALSE(INDEX_INVALID == bdei0))
             {
-                next0 = BIER_DISP_LOOKUP_NEXT_DROP;
-            }
-            else
-            {
-                next0 = BIER_DISP_LOOKUP_NEXT_DISPATCH;
+                /*
+                 * if a specific match misses, try the default
+                 */
+                bdei0 = bier_disp_table_lookup(bdti0, 0);
+
+                if (PREDICT_FALSE(INDEX_INVALID == bdei0))
+                {
+                    next0 = BIER_DISP_LOOKUP_NEXT_DROP;
+                }
             }
 
             vnet_buffer(b0)->ip.adj_index[VLIB_TX] = bdei0;
diff --git a/test/test_bier.py b/test/test_bier.py
index 48d0a297ca6..514265cb5b5 100644
--- a/test/test_bier.py
+++ b/test/test_bier.py
@@ -335,6 +335,31 @@ class TestBier(VppTestCase):
 
         self.send_and_expect(self.pg0, [p], self.pg1)
 
+        #
+        # A packet that does not match the Disposition entry gets dropped
+        #
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             MPLS(label=77, ttl=255) /
+             BIER(length=BIERLength.BIER_LEN_256, BFRID=77) /
+             IP(src="1.1.1.1", dst="232.1.1.1") /
+             UDP(sport=1234, dport=1234) /
+             Raw())
+        self.send_and_assert_no_replies(self.pg0, p*2,
+                                        "no matching disposition entry")
+
+        #
+        # Add the default route to the disposition table
+        #
+        bier_de_2 = VppBierDispEntry(self, bdt.id, 0,
+                                     BIER_HDR_PAYLOAD.BIER_HDR_PROTO_IPV4,
+                                     "0.0.0.0", 0, rpf_id=8192)
+        bier_de_2.add_vpp_config()
+
+        #
+        # now the previous packet is forwarded
+        #
+        self.send_and_expect(self.pg0, [p], self.pg1)
+
     def test_bier_e2e(self):
         """ BIER end-to-end """