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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.h>
typedef enum cnat_snat_next_
{
CNAT_SNAT_NEXT_DROP,
CNAT_SNAT_N_NEXT,
} cnat_snat_next_t;
typedef struct cnat_snat_trace_
{
u32 found;
cnat_session_t session;
} cnat_snat_trace_t;
vlib_node_registration_t cnat_snat_ip4_node;
vlib_node_registration_t cnat_snat_ip6_node;
static u8 *
format_cnat_snat_trace (u8 * s, va_list * args)
{
CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
cnat_snat_trace_t *t = va_arg (*args, cnat_snat_trace_t *);
if (t->found)
s = format (s, "found: %U", format_cnat_session, &t->session, 1);
else
s = format (s, "not found");
return s;
}
/* 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 */
always_inline uword
cnat_snat_inline (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_buffer_t * b,
cnat_node_ctx_t * ctx, int rv, cnat_session_t * session)
{
cnat_main_t *cm = &cnat_main;
ip4_header_t *ip4;
ip_protocol_t iproto;
ip6_header_t *ip6;
udp_header_t *udp0;
u32 arc_next0;
u16 next0;
u16 sport;
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;
if (iproto != IP_PROTOCOL_UDP && iproto != IP_PROTOCOL_TCP)
{
/* Dont translate */
goto trace;
}
if (!rv)
{
/* 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);
rv = cnat_search_snat_prefix (&ip46_dst_address, ctx->af);
if (!rv)
{
/* Prefix table hit, we shouldn't source NAT */
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)
{
ip46_address_set_ip4 (&session->value.cs_ip[VLIB_RX],
&cm->snat_ip4);
ip46_address_set_ip4 (&session->value.cs_ip[VLIB_TX],
&ip4->dst_address);
}
else
{
ip46_address_set_ip6 (&session->value.cs_ip[VLIB_RX],
&cm->snat_ip6);
ip46_address_set_ip6 (&session->value.cs_ip[VLIB_TX],
&ip6->dst_address);
}
/* Port allocation, first try to use the original port, allocate one
if it is already used */
sport = udp0->src_port;
rv = cnat_allocate_port (cm, &sport);
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] = udp0->dst_port;
session->value.cs_lbi = INDEX_INVALID;
session->value.flags =
CNAT_SESSION_FLAG_NO_CLIENT | CNAT_SESSION_FLAG_ALLOC_PORT;
cnat_session_create (session, ctx, 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))
{
cnat_snat_trace_t *t;
t = vlib_add_trace (vm, node, b, sizeof (*t));
if (NULL != session)
clib_memcpy (&t->session, session, sizeof (t->session));
}
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_inline, AF_IP4,
1 /* do_trace */ );
return cnat_node_inline (vm, node, frame, cnat_snat_inline, AF_IP4,
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_inline, AF_IP6,
1 /* do_trace */ );
return cnat_node_inline (vm, node, frame, cnat_snat_inline, AF_IP6,
0 /* do_trace */ );
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (cnat_snat_ip4_node) =
{
.name = "ip4-cnat-snat",
.vector_size = sizeof (u32),
.format_trace = format_cnat_snat_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 = "ip6-cnat-snat",
.vector_size = sizeof (u32),
.format_trace = format_cnat_snat_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",
}
};
/* *INDENT-ON* */
VNET_FEATURE_INIT (cnat_snat_ip4_node, static) =
{
.arc_name = "ip4-unicast",.node_name = "ip4-cnat-snat",};
VNET_FEATURE_INIT (cnat_snat_ip6_node, static) =
{
.arc_name = "ip6-unicast",.node_name = "ip6-cnat-snat",};
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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