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Vector Packet Processing
mpls_lookup.h
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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 
22 /**
23  * The arc/edge from the MPLS lookup node to the MPLS replicate node
24  */
26 
27 /*
28  * Compute flow hash.
29  * We'll use it to select which adjacency to use for this flow. And other things.
30  */
33  flow_hash_config_t flow_hash_config)
34 {
35  /*
36  * We need to byte swap so we use the numerical value. i.e. an odd label
37  * leads to an odd bucket. as opposed to a label above and below value X.
38  */
39  u8 next_label_is_entropy;
40  mpls_label_t ho_label;
41  u32 hash, value;
42 
43  ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
44  hash = vnet_mpls_uc_get_label(ho_label);
45  next_label_is_entropy = 0;
46 
47  while (MPLS_EOS != vnet_mpls_uc_get_s(ho_label))
48  {
49  hdr++;
50  ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
51  value = vnet_mpls_uc_get_label(ho_label);
52 
53  if (1 == next_label_is_entropy)
54  {
55  /*
56  * The label is an entropy value, use it alone as the hash
57  */
58  return (ho_label);
59  }
60  if (MPLS_IETF_ENTROPY_LABEL == value)
61  {
62  /*
63  * we've met a label in the stack indicating that tha next
64  * label is an entropy value
65  */
66  next_label_is_entropy = 1;
67  }
68  else
69  {
70  /*
71  * XOR the label values in the stack together to
72  * build up the hash value
73  */
74  hash ^= value;
75  }
76  }
77 
78  /*
79  * check the top nibble for v4 and v6
80  */
81  hdr++;
82 
83  switch (((u8*)hdr)[0] >> 4)
84  {
85  case 4:
86  /* incorporate the v4 flow-hash */
87  hash ^= ip4_compute_flow_hash ((const ip4_header_t *)hdr,
89  break;
90  case 6:
91  /* incorporate the v6 flow-hash */
92  hash ^= ip6_compute_flow_hash ((const ip6_header_t *)hdr,
94  break;
95  default:
96  break;
97  }
98 
99  return (hash);
100 }
101 
102 #endif /* __MPLS_LOOKUP_H__ */
u32 mpls_lookup_to_replicate_edge
The arc/edge from the MPLS lookup node to the MPLS replicate node.
Definition: mpls_lookup.h:25
static u32 ip4_compute_flow_hash(const ip4_header_t *ip, flow_hash_config_t flow_hash_config)
Definition: ip4.h:299
u32 mpls_label_t
A label value only, i.e.
Definition: packet.h:24
#define MPLS_IETF_ENTROPY_LABEL
Definition: mpls_types.h:33
#define always_inline
Definition: clib.h:92
static u32 mpls_compute_flow_hash(const mpls_unicast_header_t *hdr, flow_hash_config_t flow_hash_config)
Definition: mpls_lookup.h:32
static u32 ip6_compute_flow_hash(const ip6_header_t *ip, flow_hash_config_t flow_hash_config)
Definition: ip6.h:414
static u32 vnet_mpls_uc_get_label(mpls_label_t label_exp_s_ttl)
Definition: packet.h:77
unsigned int u32
Definition: types.h:88
mpls_label_t label_exp_s_ttl
Definition: packet.h:31
#define IP_FLOW_HASH_DEFAULT
Default: 5-tuple without the "reverse" bit.
Definition: lookup.h:69
u32 flow_hash_config_t
A flow hash configuration is a mask of the flow hash options.
Definition: lookup.h:82
static u32 vnet_mpls_uc_get_s(mpls_label_t label_exp_s_ttl)
Definition: packet.h:87
unsigned char u8
Definition: types.h:56