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/*
* 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:
*/
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