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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.
*/
#ifndef __CNAT_SESSION_H__
#define __CNAT_SESSION_H__
#include <vnet/udp/udp_packet.h>
#include <cnat/cnat_types.h>
#include <cnat/cnat_client.h>
#include <cnat/cnat_bihash.h>
/**
* A session represents the memory of a translation.
* In the tx direction (from behind to in front of the NAT), the
* session is preserved so subsequent packets follow the same path
* even if the translation has been updated. In the tx direction
* the session represents the swap from the VIP to the server address
* In the RX direction the swap is from the server address/port to VIP.
*
* A session exists only as key and value in the bihash, there is no
* pool for this object. If there were a pool, one would need to be
* concerned about what worker is using it.
*/
typedef struct cnat_session_t_
{
/**
* this key sits in the same memory location a 'key' in the bihash kvp
*/
struct
{
/**
* IP 4/6 address in the rx/tx direction
*/
ip46_address_t cs_ip[VLIB_N_DIR];
/**
* ports in rx/tx
*/
u16 cs_port[VLIB_N_DIR];
/**
* The IP protocol TCP or UDP only supported
*/
ip_protocol_t cs_proto;
/**
* The address family describing the IP addresses
*/
u8 cs_af;
/**
* input / output / fib session
*/
u8 cs_loc;
u8 __cs_pad;
} key;
/**
* this value sits in the same memory location a 'value' in the bihash kvp
*/
struct
{
/**
* The IP address to translate to.
*/
ip46_address_t cs_ip[VLIB_N_DIR];
/**
* the port to translate to.
*/
u16 cs_port[VLIB_N_DIR];
/**
* The load balance object to use to forward
*/
index_t cs_lbi;
/**
* Persist translation->ct_lb.dpoi_next_node
*/
u32 dpoi_next_node;
/**
* Timestamp index this session was last used
*/
u32 cs_ts_index;
/**
* session flags
*/
u32 flags;
u32 __pad;
} value;
} cnat_session_t;
typedef enum cnat_session_flag_t_
{
/**
* Indicates a return path session that was source NATed
* on the way in.
*/
CNAT_SESSION_FLAG_HAS_SNAT = (1 << 0),
/**
* This session source port was allocated, free it on cleanup
*/
CNAT_SESSION_FLAG_ALLOC_PORT = (1 << 1),
/**
* This session doesn't have a client, do not attempt to free it
*/
CNAT_SESSION_FLAG_NO_CLIENT = (1 << 2),
/* Do not actually translate the packet but still forward it
* Used for Maglev, with an encap */
CNAT_SESSION_FLAG_NO_NAT = (1 << 3),
/* Debug flag marking return sessions */
CNAT_SESSION_IS_RETURN = (1 << 4),
/** On conflicts when adding the return session, try to sNAT the
* forward session, and dNAT the return session with a random port */
CNAT_SESSION_RETRY_SNAT = (1 << 5),
} cnat_session_flag_t;
typedef enum cnat_session_location_t_
{
CNAT_LOCATION_INPUT = 0,
CNAT_LOCATION_OUTPUT = 1,
CNAT_LOCATION_FIB = 0xff,
} cnat_session_location_t;
extern u8 *format_cnat_session (u8 * s, va_list * args);
/**
* Ensure the session object correctly overlays the bihash key/value pair
*/
STATIC_ASSERT (STRUCT_OFFSET_OF (cnat_session_t, key) ==
STRUCT_OFFSET_OF (cnat_bihash_kv_t, key),
"key overlaps");
STATIC_ASSERT (STRUCT_OFFSET_OF (cnat_session_t, value) ==
STRUCT_OFFSET_OF (cnat_bihash_kv_t, value),
"value overlaps");
STATIC_ASSERT (sizeof (cnat_session_t) == sizeof (cnat_bihash_kv_t),
"session kvp");
/**
* The DB of sessions
*/
extern cnat_bihash_t cnat_session_db;
/**
* Callback function invoked during a walk of all translations
*/
typedef walk_rc_t (*cnat_session_walk_cb_t) (const cnat_session_t *
session, void *ctx);
/**
* Walk/visit each of the cnat session
*/
extern void cnat_session_walk (cnat_session_walk_cb_t cb, void *ctx);
/**
* Scan the session DB for expired sessions
*/
extern u64 cnat_session_scan (vlib_main_t * vm, f64 start_time, int i);
/**
* Purge all the sessions
*/
extern int cnat_session_purge (void);
/**
* Free a session & update refcounts
*/
extern void cnat_session_free (cnat_session_t * session);
/**
* Port cleanup callback
*/
extern void (*cnat_free_port_cb) (u16 port, ip_protocol_t iproto);
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
#endif
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