/* * 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__ */