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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 <cnat/cnat_src_policy.h>
#include <cnat/cnat_inline.h>
#include <cnat/cnat_session.h>
#include <cnat/cnat_translation.h>
cnat_src_policy_main_t cnat_src_policy_main;
void
cnat_register_vip_src_policy (cnat_vip_source_policy_t fp)
{
cnat_src_policy_main.vip_policy = fp;
}
cnat_source_policy_errors_t
cnat_vip_default_source_policy (vlib_main_t * vm,
vlib_buffer_t * b,
cnat_session_t * session,
u32 * rsession_flags,
const cnat_translation_t * ct,
cnat_node_ctx_t * ctx)
{
ip_protocol_t iproto;
udp_header_t *udp0;
ip4_header_t *ip4;
ip6_header_t *ip6;
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);
}
int rv = 0;
if (!session->value.cs_port[VLIB_RX])
{
u16 sport;
sport = udp0->src_port;
/* Allocate a port only if asked and if we actually sNATed */
if ((ct->flags & CNAT_TR_FLAG_ALLOCATE_PORT) &&
(*rsession_flags & CNAT_SESSION_FLAG_HAS_SNAT))
{
sport = 0; /* force allocation */
session->value.flags |= CNAT_SESSION_FLAG_ALLOC_PORT;
rv = cnat_allocate_port (&sport, iproto);
if (rv)
return CNAT_SOURCE_ERROR_EXHAUSTED_PORTS;
}
session->value.cs_port[VLIB_RX] = sport;
}
return 0;
}
always_inline cnat_src_port_allocator_t *
cnat_get_src_port_allocator (ip_protocol_t iproto)
{
cnat_src_policy_main_t *cspm = &cnat_src_policy_main;
switch (iproto)
{
case IP_PROTOCOL_TCP:
return &cspm->src_ports[CNAT_SPORT_PROTO_TCP];
case IP_PROTOCOL_UDP:
return &cspm->src_ports[CNAT_SPORT_PROTO_UDP];
case IP_PROTOCOL_ICMP:
return &cspm->src_ports[CNAT_SPORT_PROTO_ICMP];
case IP_PROTOCOL_ICMP6:
return &cspm->src_ports[CNAT_SPORT_PROTO_ICMP6];
default:
return 0;
}
}
void
cnat_free_port (u16 port, ip_protocol_t iproto)
{
cnat_src_port_allocator_t *ca;
ca = cnat_get_src_port_allocator (iproto);
if (!ca)
return;
clib_spinlock_lock (&ca->lock);
clib_bitmap_set_no_check (ca->bmap, port, 0);
clib_spinlock_unlock (&ca->lock);
}
int
cnat_allocate_port (u16 * port, ip_protocol_t iproto)
{
*port = clib_net_to_host_u16 (*port);
if (*port == 0)
*port = MIN_SRC_PORT;
cnat_src_port_allocator_t *ca;
ca = cnat_get_src_port_allocator (iproto);
if (!ca)
return -1;
clib_spinlock_lock (&ca->lock);
if (clib_bitmap_get_no_check (ca->bmap, *port))
{
*port = clib_bitmap_next_clear (ca->bmap, *port);
if (PREDICT_FALSE (*port >= UINT16_MAX))
*port = clib_bitmap_next_clear (ca->bmap, MIN_SRC_PORT);
if (PREDICT_FALSE (*port >= UINT16_MAX))
{
clib_spinlock_unlock (&ca->lock);
return -1;
}
}
clib_bitmap_set_no_check (ca->bmap, *port, 1);
*port = clib_host_to_net_u16 (*port);
clib_spinlock_unlock (&ca->lock);
return 0;
}
static clib_error_t *
cnat_src_policy_init (vlib_main_t * vm)
{
cnat_src_policy_main_t *cspm = &cnat_src_policy_main;
cspm->vip_policy = cnat_vip_default_source_policy;
cspm->default_policy = cnat_vip_default_source_policy;
vec_validate (cspm->src_ports, CNAT_N_SPORT_PROTO);
for (int i = 0; i < CNAT_N_SPORT_PROTO; i++)
{
clib_spinlock_init (&cspm->src_ports[i].lock);
clib_bitmap_validate (cspm->src_ports[i].bmap, UINT16_MAX);
}
/* Inject cleanup callback */
cnat_free_port_cb = cnat_free_port;
return (NULL);
}
VLIB_INIT_FUNCTION (cnat_src_policy_init);
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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