1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
/*
* snat_det.c - deterministic NAT
*
* Copyright (c) 2017 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.
*/
/**
* @file
* @brief deterministic NAT
*/
#include <snat/snat_det.h>
/**
* @brief Add/delete deterministic NAT mapping.
*
* Create bijective mapping of inside address to outside address and port range
* pairs, with the purpose of enabling deterministic NAT to reduce logging in
* CGN deployments.
*
* @param sm SNAT main.
* @param in_addr Inside network address.
* @param in_plen Inside network prefix length.
* @param out_addr Outside network address.
* @param out_plen Outside network prefix length.
* @param is_add If 0 delete, otherwise add.
*/
int
snat_det_add_map (snat_main_t * sm, ip4_address_t * in_addr, u8 in_plen,
ip4_address_t * out_addr, u8 out_plen, int is_add)
{
snat_det_map_t *det_map;
static snat_det_session_t empty_snat_det_session = { 0 };
snat_interface_t *i;
ip4_address_t in_cmp, out_cmp;
u8 found = 0;
in_cmp.as_u32 = in_addr->as_u32 & ip4_main.fib_masks[in_plen];
out_cmp.as_u32 = out_addr->as_u32 & ip4_main.fib_masks[out_plen];
vec_foreach (det_map, sm->det_maps)
{
/* Checking for overlapping addresses to be added here */
if (det_map->in_addr.as_u32 == in_cmp.as_u32 &&
det_map->in_plen == in_plen &&
det_map->out_addr.as_u32 == out_cmp.as_u32 &&
det_map->out_plen == out_plen)
{
found = 1;
break;
}
}
/* If found, don't add again */
if (found && is_add)
return VNET_API_ERROR_VALUE_EXIST;
/* If not found, don't delete */
if (!found && !is_add)
return VNET_API_ERROR_NO_SUCH_ENTRY;
if (is_add)
{
pool_get (sm->det_maps, det_map);
memset (det_map, 0, sizeof (*det_map));
det_map->in_addr.as_u32 = in_cmp.as_u32;
det_map->in_plen = in_plen;
det_map->out_addr.as_u32 = out_cmp.as_u32;
det_map->out_plen = out_plen;
det_map->sharing_ratio = (1 << (32 - in_plen)) / (1 << (32 - out_plen));
det_map->ports_per_host = (65535 - 1023) / det_map->sharing_ratio;
vec_validate_init_empty (det_map->sessions,
SNAT_DET_SES_PER_USER * (1 << (32 - in_plen)) -
1, empty_snat_det_session);
}
else
{
vec_free (det_map->sessions);
vec_del1 (sm->det_maps, det_map - sm->det_maps);
}
/* Add/del external address range to FIB */
/* *INDENT-OFF* */
pool_foreach (i, sm->interfaces,
({
if (i->is_inside)
continue;
snat_add_del_addr_to_fib(out_addr, out_plen, i->sw_if_index, is_add);
break;
}));
/* *INDENT-ON* */
return 0;
}
/**
* @brief The 'snat-det-expire-walk' process's main loop.
*
* Check expire time for active sessions.
*/
static uword
snat_det_expire_walk_fn (vlib_main_t * vm, vlib_node_runtime_t * rt,
vlib_frame_t * f)
{
snat_main_t *sm = &snat_main;
snat_det_map_t *dm;
snat_det_session_t *ses;
while (sm->deterministic)
{
vlib_process_wait_for_event_or_clock (vm, 10.0);
vlib_process_get_events (vm, NULL);
u32 now = (u32) vlib_time_now (vm);
/* *INDENT-OFF* */
pool_foreach (dm, sm->det_maps,
({
vec_foreach(ses, dm->sessions)
{
/* Delete if session expired */
if (ses->in_port && (ses->expire < now))
snat_det_ses_close (dm, ses);
}
}));
/* *INDENT-ON* */
}
return 0;
}
static vlib_node_registration_t snat_det_expire_walk_node;
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (snat_det_expire_walk_node, static) = {
.function = snat_det_expire_walk_fn,
.type = VLIB_NODE_TYPE_PROCESS,
.name =
"snat-det-expire-walk",
};
/* *INDENT-ON* */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
|
