net: tcp: Set the FIN_TIMEOUT to allow all FIN retries

Instead of using a fixed fin timeout, compute it based on the number
of retries. Fixes issue found by PR 44545.

Signed-off-by: Sjors Hettinga <[email protected]>

Author: ssharks

subsys/net/ip/tcp.c

@@ -28,7 +28,8 @@ LOG_MODULE_REGISTER(net_tcp, CONFIG_NET_TCP_LOG_LEVEL);
 
 #define ACK_TIMEOUT_MS CONFIG_NET_TCP_ACK_TIMEOUT
 #define ACK_TIMEOUT K_MSEC(ACK_TIMEOUT_MS)
-#define FIN_TIMEOUT_MS MSEC_PER_SEC
+/* Allow for (tcp_retries + 1) transmissions */
+#define FIN_TIMEOUT_MS (tcp_rto * (tcp_retries + 1))
 #define FIN_TIMEOUT K_MSEC(FIN_TIMEOUT_MS)
 
 static int tcp_rto = CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT;