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

[vpp.git] / src / vnet / mpls / mpls_lookup.h

diff --git a/src/vnet/mpls/mpls_lookup.h b/src/vnet/mpls/mpls_lookup.h
new file mode 100644 (file)
index 0000000..28c9124
--- /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__ */