MPLS lookup DPO does not pop the label (nor does it handle replicate)

Change-Id: I7de6b96631d1645d0eadd38525860d84d78e316d
Signed-off-by: Neale Ranns <nranns@cisco.com>

5 files changed, 165 insertions, 84 deletions

diff --git a/src/vnet/dpo/lookup_dpo.c b/src/vnet/dpo/lookup_dpo.c
index cf489d7e..26363a2f 100644
--- a/src/vnet/dpo/lookup_dpo.c
+++ b/src/vnet/dpo/lookup_dpo.c
@@ -15,8 +15,8 @@
 
 #include <vnet/ip/ip.h>
 #include <vnet/dpo/lookup_dpo.h>
-#include <vnet/dpo/load_balance.h>
-#include <vnet/mpls/mpls.h>
+#include <vnet/dpo/load_balance_map.h>
+#include <vnet/mpls/mpls_lookup.h>
 #include <vnet/fib/fib_table.h>
 #include <vnet/fib/ip4_fib.h>
 #include <vnet/fib/ip6_fib.h>
@@ -999,7 +999,7 @@ lookup_dpo_mpls_inline (vlib_main_t * vm,
 
         while (n_left_from > 0 && n_left_to_next > 0)
         {
-            u32 bi0, lkdi0, lbi0, fib_index0,  next0;
+            u32 bi0, lkdi0, lbi0, fib_index0, next0, hash0;
             const mpls_unicast_header_t * hdr0;
             const load_balance_t *lb0;
             const lookup_dpo_t * lkd0;
@@ -1043,9 +1043,44 @@ lookup_dpo_mpls_inline (vlib_main_t * vm,
             next0 = dpo0->dpoi_next_node;
             vnet_buffer(b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 
-            vlib_increment_combined_counter
-                (cm, thread_index, lbi0, 1,
-                 vlib_buffer_length_in_chain (vm, b0));
+
+            if (MPLS_IS_REPLICATE & lbi0)
+            {
+                next0 = mpls_lookup_to_replicate_edge;
+                vnet_buffer (b0)->ip.adj_index[VLIB_TX] =
+                    (lbi0 & ~MPLS_IS_REPLICATE);
+            }
+            else
+            {
+                lb0 = load_balance_get(lbi0);
+                ASSERT (lb0->lb_n_buckets > 0);
+                ASSERT (is_pow2 (lb0->lb_n_buckets));
+
+                if (PREDICT_FALSE(lb0->lb_n_buckets > 1))
+                {
+                    hash0 = vnet_buffer (b0)->ip.flow_hash =
+                        mpls_compute_flow_hash(hdr0, lb0->lb_hash_config);
+                    dpo0 = load_balance_get_fwd_bucket
+                        (lb0,
+                         (hash0 & (lb0->lb_n_buckets_minus_1)));
+                }
+                else
+                {
+                    dpo0 = load_balance_get_bucket_i (lb0, 0);
+                }
+                next0 = dpo0->dpoi_next_node;
+
+                vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+
+                vlib_increment_combined_counter
+                    (cm, thread_index, lbi0, 1,
+                     vlib_buffer_length_in_chain (vm, b0));
+            }
+
+          vnet_buffer (b0)->mpls.ttl = ((char*)hdr0)[3];
+            vnet_buffer (b0)->mpls.exp = (((char*)hdr0)[2] & 0xe) >> 1;
+            vnet_buffer (b0)->mpls.first = 1;
+            vlib_buffer_advance(b0, sizeof(*hdr0));
 
 	    if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) 
             {
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 37467182..d86f22ca 100755
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -2473,7 +2473,6 @@ ip4_rewrite_inline (vlib_main_t * vm,
 		}
 
 	      /* Verify checksum. */
-	      ASSERT (ip0->checksum == ip4_header_checksum (ip0));
 	      ASSERT (ip1->checksum == ip4_header_checksum (ip1));
 	    }
 	  else
diff --git a/src/vnet/mpls/mpls_lookup.c b/src/vnet/mpls/mpls_lookup.c
index 42e5399c..7cedc384 100644
--- a/src/vnet/mpls/mpls_lookup.c
+++ b/src/vnet/mpls/mpls_lookup.c
@@ -17,7 +17,7 @@
 
 #include <vlib/vlib.h>
 #include <vnet/pg/pg.h>
-#include <vnet/mpls/mpls.h>
+#include <vnet/mpls/mpls_lookup.h>
 #include <vnet/fib/mpls_fib.h>
 #include <vnet/dpo/load_balance_map.h>
 #include <vnet/dpo/replicate_dpo.h>
@@ -30,7 +30,7 @@ static vlib_node_registration_t mpls_lookup_node;
 /**
  * The arc/edge from the MPLS lookup node to the MPLS replicate node
  */
-static u32 mpls_lookup_to_replicate_edge;
+u32 mpls_lookup_to_replicate_edge;
 
 typedef struct {
   u32 next_index;
@@ -56,81 +56,6 @@ format_mpls_lookup_trace (u8 * s, va_list * args)
   return s;
 }
 
-/*
- * Compute flow hash. 
- * We'll use it to select which adjacency to use for this flow.  And other things.
- */
-always_inline u32
-mpls_compute_flow_hash (const mpls_unicast_header_t * hdr,
-                        flow_hash_config_t flow_hash_config)
-{
-    /*
-     * We need to byte swap so we use the numerical value. i.e. an odd label
-     * leads to an odd bucket. as opposed to a label above and below value X.
-     */
-    u8 next_label_is_entropy;
-    mpls_label_t ho_label;
-    u32 hash, value;
-
-    ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
-    hash = vnet_mpls_uc_get_label(ho_label);
-    next_label_is_entropy = 0;
-
-    while (MPLS_EOS != vnet_mpls_uc_get_s(ho_label))
-    {
-        hdr++;
-        ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
-        value = vnet_mpls_uc_get_label(ho_label);
-
-        if (1 == next_label_is_entropy)
-        {
-            /*
-             * The label is an entropy value, use it alone as the hash
-             */
-            return (ho_label);
-        }
-        if (MPLS_IETF_ENTROPY_LABEL == value)
-        {
-            /*
-             * we've met a label in the stack indicating that tha next
-             * label is an entropy value
-             */
-            next_label_is_entropy = 1;
-        }
-        else
-        {
-            /*
-             * XOR the label values in the stack together to
-             * build up the hash value
-             */
-            hash ^= value;
-        }
-    }
-
-    /*
-     * check the top nibble for v4 and v6
-     */
-    hdr++;
-
-    switch (((u8*)hdr)[0] >> 4)
-    {
-    case 4:
-        /* incorporate the v4 flow-hash */
-        hash ^= ip4_compute_flow_hash ((const ip4_header_t *)hdr,
-                                       IP_FLOW_HASH_DEFAULT);
-        break;
-    case 6:
-        /* incorporate the v6 flow-hash */
-        hash ^= ip6_compute_flow_hash ((const ip6_header_t *)hdr,
-                                       IP_FLOW_HASH_DEFAULT);
-        break;
-    default:
-        break;
-    }
-
-    return (hash);
-}
-
 static inline uword
 mpls_lookup (vlib_main_t * vm,
              vlib_node_runtime_t * node,
diff --git a/src/vnet/mpls/mpls_lookup.h b/src/vnet/mpls/mpls_lookup.h
new file mode 100644
index 00000000..28c9124f
--- /dev/null
+++ b/src/vnet/mpls/mpls_lookup.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __MPLS_LOOKUP_H__
+#define __MPLS_LOOKUP_H__
+
+#include <vnet/mpls/mpls.h>
+#include <vnet/ip/ip.h>
+
+/**
+ * The arc/edge from the MPLS lookup node to the MPLS replicate node
+ */
+u32 mpls_lookup_to_replicate_edge;
+
+/*
+ * Compute flow hash. 
+ * We'll use it to select which adjacency to use for this flow.  And other things.
+ */
+always_inline u32
+mpls_compute_flow_hash (const mpls_unicast_header_t * hdr,
+                        flow_hash_config_t flow_hash_config)
+{
+    /*
+     * We need to byte swap so we use the numerical value. i.e. an odd label
+     * leads to an odd bucket. as opposed to a label above and below value X.
+     */
+    u8 next_label_is_entropy;
+    mpls_label_t ho_label;
+    u32 hash, value;
+
+    ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
+    hash = vnet_mpls_uc_get_label(ho_label);
+    next_label_is_entropy = 0;
+
+    while (MPLS_EOS != vnet_mpls_uc_get_s(ho_label))
+    {
+        hdr++;
+        ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
+        value = vnet_mpls_uc_get_label(ho_label);
+
+        if (1 == next_label_is_entropy)
+        {
+            /*
+             * The label is an entropy value, use it alone as the hash
+             */
+            return (ho_label);
+        }
+        if (MPLS_IETF_ENTROPY_LABEL == value)
+        {
+            /*
+             * we've met a label in the stack indicating that tha next
+             * label is an entropy value
+             */
+            next_label_is_entropy = 1;
+        }
+        else
+        {
+            /*
+             * XOR the label values in the stack together to
+             * build up the hash value
+             */
+            hash ^= value;
+        }
+    }
+
+    /*
+     * check the top nibble for v4 and v6
+     */
+    hdr++;
+
+    switch (((u8*)hdr)[0] >> 4)
+    {
+    case 4:
+        /* incorporate the v4 flow-hash */
+        hash ^= ip4_compute_flow_hash ((const ip4_header_t *)hdr,
+                                       IP_FLOW_HASH_DEFAULT);
+        break;
+    case 6:
+        /* incorporate the v6 flow-hash */
+        hash ^= ip6_compute_flow_hash ((const ip6_header_t *)hdr,
+                                       IP_FLOW_HASH_DEFAULT);
+        break;
+    default:
+        break;
+    }
+
+    return (hash);
+}
+
+#endif /* __MPLS_LOOKUP_H__ */
diff --git a/test/test_mpls.py b/test/test_mpls.py
index 77cec429..e3d013af 100644
--- a/test/test_mpls.py
+++ b/test/test_mpls.py
@@ -771,6 +771,26 @@ class TestMPLS(VppTestCase):
         rx = self.pg1.get_capture(packet_count)
         self.verify_capture_ip4(self.pg1, rx, tx, ping_resp=1)
 
+        #
+        # Double pop
+        #
+        route_36_neos = VppMplsRoute(self, 36, 0,
+                                     [VppRoutePath("0.0.0.0",
+                                                   0xffffffff)])
+        route_36_neos.add_vpp_config()
+
+        self.vapi.cli("clear trace")
+        tx = self.create_stream_labelled_ip4(self.pg0, [36, 35],
+                                             ping=1, ip_itf=self.pg1)
+        self.pg0.add_stream(tx)
+
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        rx = self.pg1.get_capture(len(tx))
+        self.verify_capture_ip4(self.pg1, rx, tx, ping_resp=1)
+
+        route_36_neos.remove_vpp_config()
         route_35_eos.remove_vpp_config()
         route_34_eos.remove_vpp_config()