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/*
* 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__ */
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