Path MTU Discovery functions. More...

#include "he.h"

Include dependency graph for pmtud.h:

This graph shows which files directly or indirectly include this file:

Macros
#define	MAX_PROBES 3

#define	MIN_PLPMTU 512
	The smallest PMTU the discovery process will attempt to use.

#define	MAX_PLPMTU
	The largest PMTU the discovery process will attempt to use. More...

#define	INITIAL_PLPMTU 1250
	The initial PMTU the discovery process will attempt to use first.

#define	PMTUD_PROBE_TIMEOUT_MS 5000
	The default timeout for waiting for an acknowledgement to a probe packet, in milliseconds.

#define	PMTUD_PROBE_BIG_STEP 32
	Number of bytes to increase for the next PROBED_SIZE.

#define	PMTUD_PROBE_SMALL_STEP 8
	The minimal number of bytes to increase for the next PROBED_SIZE.

#define	PMTUD_ERROR_RETRY_TIMEOUT_MS (60 * 1000)
	The default timeout for retrying a failed PMTUD probe.

#define	PMTUD_SUCCESSFUL_SEARCH_RETRY_TIMEOUT_MS (10 * 60 * 1000)

Functions
he_return_code_t	he_internal_pmtud_send_probe (he_conn_t *conn, uint16_t probe_mtu)
	Send PMTUD probe message with the given probe mtu size. More...

he_return_code_t	he_internal_pmtud_handle_probe_ack (he_conn_t *conn, uint16_t probe_id)
	Called when the conn receives an acknowledgement of a probe message. More...

he_return_code_t	he_internal_pmtud_handle_probe_timeout (he_conn_t *conn)
	Called when the timer of a probe expired. More...

he_return_code_t	he_internal_pmtud_start_base_probing (he_conn_t *conn)
	Start PMTUD discovery and change state to BASE. More...

he_return_code_t	he_internal_pmtud_base_confirmed (he_conn_t *conn)
	Called when the acknowledgement of current BASE_PLPMTU probing received. More...

he_return_code_t	he_internal_pmtud_confirm_base_failed (he_conn_t *conn)
	Called when current state is BASE and PROBE_COUNT reaches MAX_PROBES. More...

he_return_code_t	he_internal_pmtud_start_searching (he_conn_t *conn)
	Called when probing for the BASE_PLPMTU completes. More...

he_return_code_t	he_internal_pmtud_search_completed (he_conn_t *conn)
	Called when the PROBE_COUNT reaches MAX_PROBES, a validated PTB is received that corresponds to the last successfully probed size (PL_PTB_SIZE = PLPMTU), or a probe of size MAX_PLPMTU is acknowledged (PLPMTU = MAX_PLPMTU) More...

he_return_code_t	he_internal_pmtud_blackhole_detected (he_conn_t *conn)
	Called when a black hole situation is detected. More...

he_return_code_t	he_internal_pmtud_retry_probe (he_conn_t *conn, int delay_ms)
	Called when we want to retry probing. More...

Detailed Description

Path MTU Discovery functions.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Macro Definition Documentation

◆ MAX_PLPMTU

#define MAX_PLPMTU

Value:

(HE_MAX_WIRE_MTU - HE_IPV4_HEADER_SIZE - HE_UDP_HEADER_SIZE - sizeof(he_wire_hdr_t) - \

HE_WOLF_MAX_HEADER_SIZE - sizeof(he_msg_data_t))

The largest PMTU the discovery process will attempt to use.

◆ MAX_PROBES

#define MAX_PROBES 3

The maximum value of the PROBE_COUNT counter. MAX_PROBES represents the limit for the number of consecutive probe attempts of any size.

Function Documentation

◆ he_internal_pmtud_base_confirmed()

he_return_code_t he_internal_pmtud_base_confirmed ( he_conn_t * conn )

Called when the acknowledgement of current BASE_PLPMTU probing received.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_INVALID_STATE if current PMTUD state is not BASE.

Note: This function triggers a pmtud_state_change_cb callback to enter the Searching state.

◆ he_internal_pmtud_blackhole_detected()

he_return_code_t he_internal_pmtud_blackhole_detected ( he_conn_t * conn )

Called when a black hole situation is detected.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_INVALID_STATE if current PMTUD state is not SEARCHING.

Note: This function triggers a pmtud_state_change_cb callback to enter the BASE state.

◆ he_internal_pmtud_confirm_base_failed()

he_return_code_t he_internal_pmtud_confirm_base_failed ( he_conn_t * conn )

Called when current state is BASE and PROBE_COUNT reaches MAX_PROBES.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_INVALID_STATE if current PMTUD state is not BASE.

Note: This function changes conn->pmtu_state and triggers a pmtud_state_change_cb callback.

◆ he_internal_pmtud_handle_probe_ack()

he_return_code_t he_internal_pmtud_handle_probe_ack	(	he_conn_t *	conn,
		uint16_t	probe_id
	)

Called when the conn receives an acknowledgement of a probe message.

Parameters

conn	A pointer to a valid connection conn
probe_id	Id of the probe message

Returns: HE_SUCCESS if the probe ack message is handled

Note: This function may trigger pmtud_time_cb and/or pmtud_state_change callbacks depending on current state.

◆ he_internal_pmtud_handle_probe_timeout()

he_return_code_t he_internal_pmtud_handle_probe_timeout ( he_conn_t * conn )

Called when the timer of a probe expired.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the probe timeout is handled

Note: This function may trigger pmtud_time_cb and/or pmtud_state_change callbacks depending on current state.

◆ he_internal_pmtud_retry_probe()

he_return_code_t he_internal_pmtud_retry_probe	(	he_conn_t *	conn,
		int	delay_ms
	)

Called when we want to retry probing.

Parameters

conn	A pointer to a valid connection conn
delay_ms	Delay in milliseconds to retry probing

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_PMTUD_CALLBACKS_NOT_SET if PMTUD callbacks are not set. Else it is the result of a pmtud_time_cb call.

Note: This function will also trigger a pmtud_time_cb callback to start the probe after the specified delay.

◆ he_internal_pmtud_search_completed()

he_return_code_t he_internal_pmtud_search_completed ( he_conn_t * conn )

Called when the PROBE_COUNT reaches MAX_PROBES, a validated PTB is received that corresponds to the last successfully probed size (PL_PTB_SIZE = PLPMTU), or a probe of size MAX_PLPMTU is acknowledged (PLPMTU = MAX_PLPMTU)

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_INVALID_STATE if current PMTUD state is not SEARCHING.

Note: This function changes conn->pmtu_state and triggers a pmtud_state_change_cb callback. This function will also trigger a pmtud_time_cb callback to check the current PMTU periodically.

◆ he_internal_pmtud_send_probe()

he_return_code_t he_internal_pmtud_send_probe	(	he_conn_t *	conn,
		uint16_t	probe_mtu
	)

Send PMTUD probe message with the given probe mtu size.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the probe message is sent successfully

Note: This function triggers a pmtud_time_cb callback.

◆ he_internal_pmtud_start_base_probing()

he_return_code_t he_internal_pmtud_start_base_probing ( he_conn_t * conn )

Start PMTUD discovery and change state to BASE.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_INVALID_STATE if current PMTUD state is not DISABLED or SEARCHING or SEARCH_COMPLETE.

Note: This function changes conn->pmtu_state and triggers a pmtud_state_change_cb callback.

◆ he_internal_pmtud_start_searching()

he_return_code_t he_internal_pmtud_start_searching ( he_conn_t * conn )

Called when probing for the BASE_PLPMTU completes.

Parameters

conn	A pointer to a valid connection conn

Returns: HE_SUCCESS if the operation succeeds. HE_ERR_INVALID_STATE if current PMTUD state is not BASE or SEARCH_COMPLETE or ERROR.

Note: This function changes conn->pmtu_state and triggers a pmtud_state_change_cb callback. While PMTUD stays in the SEARCHING state, it will trigger the pmtud_time_cb callback for each probing attempt.

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ MAX_PLPMTU

◆ MAX_PROBES

Function Documentation

◆ he_internal_pmtud_base_confirmed()

◆ he_internal_pmtud_blackhole_detected()

◆ he_internal_pmtud_confirm_base_failed()

◆ he_internal_pmtud_handle_probe_ack()

◆ he_internal_pmtud_handle_probe_timeout()

◆ he_internal_pmtud_retry_probe()

◆ he_internal_pmtud_search_completed()

◆ he_internal_pmtud_send_probe()

◆ he_internal_pmtud_start_base_probing()

◆ he_internal_pmtud_start_searching()