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Neale Ranns6af1c042017-05-26 03:48:53 -07001/*
2 * Copyright (c) 2015 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16#ifndef __MPLS_LOOKUP_H__
17#define __MPLS_LOOKUP_H__
18
19#include <vnet/mpls/mpls.h>
20#include <vnet/ip/ip.h>
21
22/**
23 * The arc/edge from the MPLS lookup node to the MPLS replicate node
24 */
25u32 mpls_lookup_to_replicate_edge;
26
Neale Rannsce9e0b42018-08-01 12:53:17 -070027/**
28 * Enum of statically configred MPLS lookup next nodes
29 */
30typedef enum mpls_lookup_next_t_
31{
32 MPLS_LOOKUP_NEXT_DROP = 0,
33} mpls_lookup_next_t;
34
Neale Ranns6af1c042017-05-26 03:48:53 -070035/*
36 * Compute flow hash.
37 * We'll use it to select which adjacency to use for this flow. And other things.
38 */
39always_inline u32
40mpls_compute_flow_hash (const mpls_unicast_header_t * hdr,
41 flow_hash_config_t flow_hash_config)
42{
43 /*
44 * We need to byte swap so we use the numerical value. i.e. an odd label
45 * leads to an odd bucket. as opposed to a label above and below value X.
46 */
47 u8 next_label_is_entropy;
48 mpls_label_t ho_label;
49 u32 hash, value;
50
51 ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
52 hash = vnet_mpls_uc_get_label(ho_label);
53 next_label_is_entropy = 0;
54
55 while (MPLS_EOS != vnet_mpls_uc_get_s(ho_label))
56 {
57 hdr++;
58 ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
59 value = vnet_mpls_uc_get_label(ho_label);
60
61 if (1 == next_label_is_entropy)
62 {
63 /*
64 * The label is an entropy value, use it alone as the hash
65 */
66 return (ho_label);
67 }
68 if (MPLS_IETF_ENTROPY_LABEL == value)
69 {
70 /*
71 * we've met a label in the stack indicating that tha next
72 * label is an entropy value
73 */
74 next_label_is_entropy = 1;
75 }
76 else
77 {
78 /*
79 * XOR the label values in the stack together to
80 * build up the hash value
81 */
82 hash ^= value;
83 }
84 }
85
86 /*
87 * check the top nibble for v4 and v6
88 */
89 hdr++;
90
91 switch (((u8*)hdr)[0] >> 4)
92 {
93 case 4:
94 /* incorporate the v4 flow-hash */
95 hash ^= ip4_compute_flow_hash ((const ip4_header_t *)hdr,
96 IP_FLOW_HASH_DEFAULT);
97 break;
98 case 6:
99 /* incorporate the v6 flow-hash */
100 hash ^= ip6_compute_flow_hash ((const ip6_header_t *)hdr,
101 IP_FLOW_HASH_DEFAULT);
102 break;
103 default:
104 break;
105 }
106
107 return (hash);
108}
109
110#endif /* __MPLS_LOOKUP_H__ */