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net: tcp: Deprecate CONFIG_NET_TCP_ACK_TIMEOUT

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Deprecate CONFIG_NET_TCP_ACK_TIMEOUT as it is redundant with the
combination of CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT and
CONFIG_NET_TCP_RETRY_COUNT. The total retransmission timeout (i. e.
waiting for ACK) should depend on the individual retransmission timeout
and retry count, having separate config is simply ambiguous and
confusing for users.

Moreover, the config was currently only used during TCP handshake, and
for that purpose we could use the very same timeout that is used for the
FIN timeout. Therefore, repurpose the fin_timeout_ms to be a generic,
maximum timeout at the TCP stack.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
This commit is contained in:
Robert Lubos 2024-03-26 11:34:29 +01:00 committed by Anas Nashif
parent 29aaaa2e60
commit f211cd6345
4 changed files with 22 additions and 16 deletions
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7
doc/releases/migration-guide-3.7.rst
View file

@ -220,6 +220,13 @@ Networking
``wifi -h`` will give more information about the usage of connect command.
(:github:`70024`)
* The Kconfig ``CONFIG_NET_TCP_ACK_TIMEOUT`` has been deprecated. Its usage was
limited to TCP handshake only, and in such case the total timeout should depend
on the total retransmission timeout (as in other cases) making the config
redundant and confusing. Use ``CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT`` and
``CONFIG_NET_TCP_RETRY_COUNT`` instead to control the total timeout at the
TCP level. (:github:`70731`)
Other Subsystems
****************

8
subsys/net/ip/Kconfig.tcp
View file

@ -66,14 +66,14 @@ config NET_TCP_TIME_WAIT_DELAY
Value of 0 disables TIME_WAIT state completely.
config NET_TCP_ACK_TIMEOUT
int "How long to wait for ACK (in milliseconds)"
int "[DEPRECATED] How long to wait for ACK (in milliseconds)"
depends on NET_TCP
default 1000
range 1 2147483647
help
This value affects the timeout when waiting ACK to arrive in
various TCP states. The value is in milliseconds. Note that
having a very low value here could prevent connectivity.
Deprecated. Use CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT and
CONFIG_NET_TCP_RETRY_COUNT to control the total timeout at the TCP
level.
config NET_TCP_INIT_RETRANSMISSION_TIMEOUT
int "Initial value of Retransmission Timeout (RTO) (in milliseconds)"

22
subsys/net/ip/tcp.c
View file

@ -26,18 +26,18 @@ LOG_MODULE_REGISTER(net_tcp, CONFIG_NET_TCP_LOG_LEVEL);
#include "net_private.h"
#include "tcp_internal.h"
#define ACK_TIMEOUT_MS CONFIG_NET_TCP_ACK_TIMEOUT
#define ACK_TIMEOUT_MS tcp_max_timeout_ms
#define ACK_TIMEOUT K_MSEC(ACK_TIMEOUT_MS)
#define LAST_ACK_TIMEOUT_MS tcp_fin_timeout_ms
#define LAST_ACK_TIMEOUT_MS tcp_max_timeout_ms
#define LAST_ACK_TIMEOUT K_MSEC(LAST_ACK_TIMEOUT_MS)
#define FIN_TIMEOUT K_MSEC(tcp_fin_timeout_ms)
#define FIN_TIMEOUT K_MSEC(tcp_max_timeout_ms)
#define ACK_DELAY K_MSEC(100)
#define ZWP_MAX_DELAY_MS 120000
#define DUPLICATE_ACK_RETRANSMIT_TRHESHOLD 3
static int tcp_rto = CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT;
static int tcp_retries = CONFIG_NET_TCP_RETRY_COUNT;
static int tcp_fin_timeout_ms;
static int tcp_max_timeout_ms;
static int tcp_rx_window =
#if (CONFIG_NET_TCP_MAX_RECV_WINDOW_SIZE != 0)
CONFIG_NET_TCP_MAX_RECV_WINDOW_SIZE;
@ -1821,7 +1821,7 @@ static void tcp_resend_data(struct k_work *work)
if (conn->in_close && conn->send_data_total == 0) {
NET_DBG("TCP connection in %s close, "
"not disposing yet (waiting %dms)",
"active", tcp_fin_timeout_ms);
"active", tcp_max_timeout_ms);
k_work_reschedule_for_queue(&tcp_work_q,
&conn->fin_timer,
FIN_TIMEOUT);
@ -1896,7 +1896,7 @@ static void tcp_fin_timeout(struct k_work *work)
return;
}
NET_DBG("Did not receive %s in %dms", "FIN", tcp_fin_timeout_ms);
NET_DBG("Did not receive %s in %dms", "FIN", tcp_max_timeout_ms);
NET_DBG("conn: %p %s", conn, tcp_conn_state(conn, NULL));
(void)tcp_conn_close(conn, -ETIMEDOUT);
@ -3564,7 +3564,7 @@ int net_tcp_put(struct net_context *context)
NET_DBG("TCP connection in %s close, "
"not disposing yet (waiting %dms)",
"active", tcp_fin_timeout_ms);
"active", tcp_max_timeout_ms);
k_work_reschedule_for_queue(&tcp_work_q,
&conn->fin_timer,
FIN_TIMEOUT);
@ -4445,18 +4445,18 @@ void net_tcp_init(void)
NULL);
/* Compute the largest possible retransmission timeout */
tcp_fin_timeout_ms = 0;
tcp_max_timeout_ms = 0;
rto = tcp_rto;
for (i = 0; i < tcp_retries; i++) {
tcp_fin_timeout_ms += rto;
tcp_max_timeout_ms += rto;
rto += rto >> 1;
}
/* At the last timeout cicle */
tcp_fin_timeout_ms += tcp_rto;
tcp_max_timeout_ms += tcp_rto;
/* When CONFIG_NET_TCP_RANDOMIZED_RTO is active in can be worse case 1.5 times larger */
if (IS_ENABLED(CONFIG_NET_TCP_RANDOMIZED_RTO)) {
tcp_fin_timeout_ms += tcp_fin_timeout_ms >> 1;
tcp_max_timeout_ms += tcp_max_timeout_ms >> 1;
}
k_thread_name_set(&tcp_work_q.thread, "tcp_work");

1
tests/net/all/prj.conf
View file

@ -126,7 +126,6 @@ CONFIG_NET_MAX_ROUTERS=3
CONFIG_NET_TCP=y
CONFIG_NET_TCP_LOG_LEVEL_DBG=y
CONFIG_NET_TCP_TIME_WAIT_DELAY=20000
CONFIG_NET_TCP_ACK_TIMEOUT=30
CONFIG_NET_TCP_CHECKSUM=y
CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT=400
CONFIG_NET_TCP_RETRY_COUNT=10