aboutsummaryrefslogtreecommitdiffstats
path: root/src/plugins/cnat/cnat_node_snat.c
blob: 9212d67ead6a5901530490e5062549b900ec15ff (plain)
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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/*
 * Copyright (c) 2020 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.
 */

#include <vlibmemory/api.h>
#include <cnat/cnat_node.h>
#include <cnat/cnat_snat_policy.h>
#include <cnat/cnat_inline.h>
#include <cnat/cnat_src_policy.h>

typedef enum cnat_snat_next_
{
  CNAT_SNAT_NEXT_DROP,
  CNAT_SNAT_N_NEXT,
} cnat_snat_next_t;

vlib_node_registration_t cnat_snat_ip4_node;
vlib_node_registration_t cnat_snat_ip6_node;

/* CNat sub for source NAT as a feature arc on ip[46]-unicast
   This node's sub shouldn't apply to the same flows as
   cnat_vip_inline */
static uword
cnat_snat_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
		   vlib_buffer_t *b, cnat_node_ctx_t *ctx,
		   int session_not_found, cnat_session_t *session)
{
  cnat_snat_policy_main_t *cpm = &cnat_snat_policy_main;
  ip4_header_t *ip4 = NULL;
  ip_protocol_t iproto;
  ip6_header_t *ip6 = NULL;
  udp_header_t *udp0;
  u32 arc_next0;
  u16 next0;
  u16 sport;
  u8 trace_flags = 0;
  int rv, do_snat;

  if (AF_IP4 == ctx->af)
    {
      ip4 = vlib_buffer_get_current (b);
      iproto = ip4->protocol;
      udp0 = (udp_header_t *) (ip4 + 1);
    }
  else
    {
      ip6 = vlib_buffer_get_current (b);
      iproto = ip6->protocol;
      udp0 = (udp_header_t *) (ip6 + 1);
    }

  /* By default don't follow previous next0 */
  vnet_feature_next (&arc_next0, b);
  next0 = arc_next0;

  /* Wrong session key */
  if (session->key.cs_proto == 0)
    goto trace;

  if (!session_not_found)
    {
      /* session table hit */
      cnat_timestamp_update (session->value.cs_ts_index, ctx->now);
    }
  else
    {
      ip46_address_t ip46_dst_address;
      if (AF_IP4 == ctx->af)
	ip46_address_set_ip4 (&ip46_dst_address, &ip4->dst_address);
      else
	ip46_address_set_ip6 (&ip46_dst_address, &ip6->dst_address);

      do_snat = cpm->snat_policy (b, session);
      if (!do_snat)
	goto trace;

      /* New flow, create the sessions if necessary. session will be a snat
         session, and rsession will be a dnat session
         Note: packet going through this path are going to the outside,
         so they will never hit the NAT again (they are not going towards
         a VIP) */
      if (AF_IP4 == ctx->af)
	{
	  if (!(cpm->snat_ip4.ce_flags & CNAT_EP_FLAG_RESOLVED))
	    goto trace;
	  ip46_address_set_ip4 (&session->value.cs_ip[VLIB_RX],
				&ip_addr_v4 (&cpm->snat_ip4.ce_ip));
	  ip46_address_set_ip4 (&session->value.cs_ip[VLIB_TX],
				&ip4->dst_address);
	}
      else
	{
	  if (!(cpm->snat_ip6.ce_flags & CNAT_EP_FLAG_RESOLVED))
	    goto trace;
	  ip46_address_set_ip6 (&session->value.cs_ip[VLIB_RX],
				&ip_addr_v6 (&cpm->snat_ip6.ce_ip));
	  ip46_address_set_ip6 (&session->value.cs_ip[VLIB_TX],
				&ip6->dst_address);
	}


      sport = 0;
      rv = cnat_allocate_port (&sport, iproto);
      if (rv)
	{
	  vlib_node_increment_counter (vm, cnat_snat_ip4_node.index,
				       CNAT_ERROR_EXHAUSTED_PORTS, 1);
	  next0 = CNAT_SNAT_NEXT_DROP;
	  goto trace;
	}
      session->value.cs_port[VLIB_RX] = sport;
      session->value.cs_port[VLIB_TX] = sport;
      if (iproto == IP_PROTOCOL_TCP || iproto == IP_PROTOCOL_UDP)
	session->value.cs_port[VLIB_TX] = udp0->dst_port;

      session->value.cs_lbi = INDEX_INVALID;
      session->value.flags =
	CNAT_SESSION_FLAG_NO_CLIENT | CNAT_SESSION_FLAG_ALLOC_PORT;
      trace_flags |= CNAT_TRACE_SESSION_CREATED;

      cnat_session_create (session, ctx, CNAT_LOCATION_FIB,
			   CNAT_SESSION_FLAG_HAS_SNAT);
    }


  if (AF_IP4 == ctx->af)
    cnat_translation_ip4 (session, ip4, udp0);
  else
    cnat_translation_ip6 (session, ip6, udp0);

trace:
  if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
    {
      trace_flags |= session_not_found ? 0 : CNAT_TRACE_SESSION_FOUND;
      cnat_add_trace (vm, node, b, session, NULL, trace_flags);
    }
  return next0;
}

VLIB_NODE_FN (cnat_snat_ip4_node) (vlib_main_t * vm,
				   vlib_node_runtime_t * node,
				   vlib_frame_t * frame)
{
  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
    return cnat_node_inline (vm, node, frame, cnat_snat_node_fn, AF_IP4,
			     CNAT_LOCATION_FIB, 1 /* do_trace */);
  return cnat_node_inline (vm, node, frame, cnat_snat_node_fn, AF_IP4,
			   CNAT_LOCATION_FIB, 0 /* do_trace */);
}

VLIB_NODE_FN (cnat_snat_ip6_node) (vlib_main_t * vm,
				   vlib_node_runtime_t * node,
				   vlib_frame_t * frame)
{
  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
    return cnat_node_inline (vm, node, frame, cnat_snat_node_fn, AF_IP6,
			     CNAT_LOCATION_FIB, 1 /* do_trace */);
  return cnat_node_inline (vm, node, frame, cnat_snat_node_fn, AF_IP6,
			   CNAT_LOCATION_FIB, 0 /* do_trace */);
}

VLIB_REGISTER_NODE (cnat_snat_ip4_node) = {
  .name = "cnat-snat-ip4",
  .vector_size = sizeof (u32),
  .format_trace = format_cnat_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = CNAT_N_ERROR,
  .error_strings = cnat_error_strings,
  .n_next_nodes = CNAT_SNAT_N_NEXT,
  .next_nodes = {
      [CNAT_SNAT_NEXT_DROP] = "ip4-drop",
  },
};

VLIB_REGISTER_NODE (cnat_snat_ip6_node) = {
  .name = "cnat-snat-ip6",
  .vector_size = sizeof (u32),
  .format_trace = format_cnat_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = CNAT_N_ERROR,
  .error_strings = cnat_error_strings,
  .n_next_nodes = CNAT_SNAT_N_NEXT,
  .next_nodes = {
      [CNAT_SNAT_NEXT_DROP] = "ip6-drop",
  },
};

VNET_FEATURE_INIT (cnat_snat_ip4_node, static) = {
  .arc_name = "ip4-unicast",
  .node_name = "cnat-snat-ip4",
};

VNET_FEATURE_INIT (cnat_snat_ip6_node, static) = {
  .arc_name = "ip6-unicast",
  .node_name = "cnat-snat-ip6",
};

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */