1/*
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#include <vnet/bier/bier_fwd.h>
22
23/**
24 * The arc/edge from the MPLS lookup node to the MPLS replicate node
25 */
26extern u32 mpls_lookup_to_replicate_edge;
27
28/**
29 * Enum of statically configred MPLS lookup next nodes
30 */
31typedef enum mpls_lookup_next_t_
32{
33    MPLS_LOOKUP_NEXT_DROP = 0,
34} mpls_lookup_next_t;
35
36/*
37 * Compute flow hash.
38 * We'll use it to select which adjacency to use for this flow.  And other things.
39 */
40always_inline u32
41mpls_compute_flow_hash (const mpls_unicast_header_t * hdr,
42                        flow_hash_config_t flow_hash_config)
43{
44    /*
45     * We need to byte swap so we use the numerical value. i.e. an odd label
46     * leads to an odd bucket. as opposed to a label above and below value X.
47     */
48    u8 next_label_is_entropy;
49    mpls_label_t ho_label;
50    u32 hash, value;
51
52    ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
53    hash = vnet_mpls_uc_get_label(ho_label);
54    next_label_is_entropy = 0;
55
56    while (MPLS_EOS != vnet_mpls_uc_get_s(ho_label))
57    {
58        hdr++;
59        ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
60        value = vnet_mpls_uc_get_label(ho_label);
61
62        if (1 == next_label_is_entropy)
63        {
64            /*
65             * The label is an entropy value, use it alone as the hash
66             */
67            return (ho_label);
68        }
69        if (MPLS_IETF_ENTROPY_LABEL == value)
70        {
71            /*
72             * we've met a label in the stack indicating that tha next
73             * label is an entropy value
74             */
75            next_label_is_entropy = 1;
76        }
77        else
78        {
79            /*
80             * XOR the label values in the stack together to
81             * build up the hash value
82             */
83            hash ^= value;
84        }
85    }
86
87    /*
88     * check the top nibble for v4 and v6
89     */
90    hdr++;
91
92    switch (((u8*)hdr)[0] >> 4)
93    {
94    case 4:
95        /* incorporate the v4 flow-hash */
96        hash ^= ip4_compute_flow_hash ((const ip4_header_t *)hdr,
97                                       IP_FLOW_HASH_DEFAULT);
98        break;
99    case 6:
100        /* incorporate the v6 flow-hash */
101        hash ^= ip6_compute_flow_hash ((const ip6_header_t *)hdr,
102                                       IP_FLOW_HASH_DEFAULT);
103        break;
104    case 5:
105        /* incorporate the bier flow-hash */
106        hash ^= bier_compute_flow_hash ((const bier_hdr_t *)hdr);
107        break;
108    default:
109        break;
110    }
111
112    return (hash);
113}
114
115#endif /* __MPLS_LOOKUP_H__ */
116