gnrc/tcp : Expose configurations to Kconfig

sys/include/net/gnrc/tcp.h

@@ -150,7 +150,7 @@ int gnrc_tcp_open_active(gnrc_tcp_tcb_t *tcb, const gnrc_tcp_ep_t *remote,
  *                    or the address in @p local is invalid.
  * @return   -EISCONN if TCB is already in use.
  * @return   -ENOMEM if the receive buffer for the TCB could not be allocated.
- *            Hint: Increase "GNRC_TCP_RCV_BUFFERS".
+ *            Hint: Increase "CONFIG_GNRC_TCP_RCV_BUFFERS".
  */
 int gnrc_tcp_open_passive(gnrc_tcp_tcb_t *tcb, const gnrc_tcp_ep_t *local);
 

sys/include/net/gnrc/tcp/config.h

@@ -26,114 +26,147 @@
 extern "C" {
 #endif
 
+/**
+ * @defgroup net_gnrc_tcp_conf GNRC TCP compile configurations
+ * @ingroup net_gnrc_conf
+ *
+ * ## Calculating RTO
+ * To calculate retransmission timeout (RTO), Round Trip Time (RTT) needs to be
+ * taken into account. SRTT (smoothed round-trip time) and RTTVAR (round-trip
+ * time variation) are hence calculated as follows:
+ *
+ *     RTTVAR <- (1 - beta) * RTTVAR + beta * |SRTT - R'|
+ *     SRTT <- (1 - alpha) * SRTT + alpha * R'
+ *
+ * where alpha ( 1 / @ref CONFIG_GNRC_TCP_RTO_A_DIV ) and beta
+ * ( 1 / @ref CONFIG_GNRC_TCP_RTO_B_DIV) are constants, and R' is the
+ * instantaneous RTT value.
+ *
+ * RTO is then calculated as :
+ *
+ *     RTO <- SRTT + max (G, K*RTTVAR)
+ *
+ * where K is a constant, and G is clock granularity in seconds
+ * ( @ref CONFIG_GNRC_TCP_RTO_GRANULARITY).
+ * For more information refer to https://tools.ietf.org/html/rfc6298
+ * @{
+ */
 /**
  * @brief Timeout duration for user calls. Default is 2 minutes.
  */
-#ifndef GNRC_TCP_CONNECTION_TIMEOUT_DURATION
-#define GNRC_TCP_CONNECTION_TIMEOUT_DURATION (120U * US_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION
+#define CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION (120U * US_PER_SEC)
 #endif
 
 /**
  * @brief Maximum segment lifetime (MSL). Default is 30 seconds.
  */
-#ifndef GNRC_TCP_MSL
-#define GNRC_TCP_MSL (30U * US_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_MSL
+#define CONFIG_GNRC_TCP_MSL (30U * US_PER_SEC)
 #endif
 
 /**
  * @brief Maximum Segment Size (MSS).
  */
-#ifndef GNRC_TCP_MSS
+#ifndef CONFIG_GNRC_TCP_MSS
 #ifdef  MODULE_GNRC_IPV6
-#define GNRC_TCP_MSS (1220U) /**< If IPv6 is used. Get MSS = 1280 - IPv6 Hdr - TCP Hdr = 1220 */
+#define CONFIG_GNRC_TCP_MSS (1220U) /**< If IPv6 is used. Get MSS = 1280 - IPv6 Hdr - TCP Hdr = 1220 */
 #else
-#define GNRC_TCP_MSS (576U) /**< Default MSS */
+#define CONFIG_GNRC_TCP_MSS (576U) /**< Default MSS */
 #endif
 #endif
 
 /**
  * @brief MSS Multiplicator = Number of MSS sized packets stored in receive buffer
  */
-#ifndef GNRC_TCP_MSS_MULTIPLICATOR
-#define GNRC_TCP_MSS_MULTIPLICATOR (1U)
+#ifndef CONFIG_GNRC_TCP_MSS_MULTIPLICATOR
+#define CONFIG_GNRC_TCP_MSS_MULTIPLICATOR (1U)
 #endif
 
 /**
  * @brief Default receive window size
  */
-#ifndef GNRC_TCP_DEFAULT_WINDOW
-#define GNRC_TCP_DEFAULT_WINDOW (GNRC_TCP_MSS * GNRC_TCP_MSS_MULTIPLICATOR)
+#ifndef CONFIG_GNRC_TCP_DEFAULT_WINDOW
+#define CONFIG_GNRC_TCP_DEFAULT_WINDOW (CONFIG_GNRC_TCP_MSS * CONFIG_GNRC_TCP_MSS_MULTIPLICATOR)
 #endif
 
 /**
- * @brief Number of preallocated receive buffers
+ * @brief Number of preallocated receive buffers.
+ *
+ * This value determines how many parallel TCP connections can be active at the
+ * same time.
  */
-#ifndef GNRC_TCP_RCV_BUFFERS
-#define GNRC_TCP_RCV_BUFFERS (1U)
+#ifndef CONFIG_GNRC_TCP_RCV_BUFFERS
+#define CONFIG_GNRC_TCP_RCV_BUFFERS (1U)
 #endif
 
 /**
  * @brief Default receive buffer size
  */
 #ifndef GNRC_TCP_RCV_BUF_SIZE
-#define GNRC_TCP_RCV_BUF_SIZE (GNRC_TCP_DEFAULT_WINDOW)
+#define GNRC_TCP_RCV_BUF_SIZE (CONFIG_GNRC_TCP_DEFAULT_WINDOW)
 #endif
 
 /**
  * @brief Lower bound for RTO = 1 sec (see RFC 6298)
+ *
+ * @note Retransmission Timeout (RTO) determines how long TCP waits for
+ * acknowledgment (ACK) of transmitted segment. If the acknowledgment
+ * isn't received within this time it is considered lost.
  */
-#ifndef GNRC_TCP_RTO_LOWER_BOUND
-#define GNRC_TCP_RTO_LOWER_BOUND (1U * US_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_RTO_LOWER_BOUND
+#define CONFIG_GNRC_TCP_RTO_LOWER_BOUND (1U * US_PER_SEC)
 #endif
 
 /**
  * @brief Upper bound for RTO = 60 sec (see RFC 6298)
  */
-#ifndef GNRC_TCP_RTO_UPPER_BOUND
-#define GNRC_TCP_RTO_UPPER_BOUND (60U * US_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_RTO_UPPER_BOUND
+#define CONFIG_GNRC_TCP_RTO_UPPER_BOUND (60U * US_PER_SEC)
 #endif
 
 /**
  * @brief Assumes clock granularity for TCP of 10 ms (see RFC 6298)
  */
-#ifndef GNRC_TCP_RTO_GRANULARITY
-#define GNRC_TCP_RTO_GRANULARITY (10U * MS_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_RTO_GRANULARITY
+#define CONFIG_GNRC_TCP_RTO_GRANULARITY (10U * MS_PER_SEC)
 #endif
 
 /**
  * @brief Alpha value for RTO calculation, default is 1/8
  */
-#ifndef GNRC_TCP_RTO_A_DIV
-#define GNRC_TCP_RTO_A_DIV (8U)
+#ifndef CONFIG_GNRC_TCP_RTO_A_DIV
+#define CONFIG_GNRC_TCP_RTO_A_DIV (8U)
 #endif
 
 /**
  * @brief Beta value for RTO calculation, default is 1/4
  */
-#ifndef GNRC_TCP_RTO_B_DIV
-#define GNRC_TCP_RTO_B_DIV (4U)
+#ifndef CONFIG_GNRC_TCP_RTO_B_DIV
+#define CONFIG_GNRC_TCP_RTO_B_DIV (4U)
 #endif
 
 /**
  * @brief K value for RTO calculation, default is 4
  */
-#ifndef GNRC_TCP_RTO_K
-#define GNRC_TCP_RTO_K (4U)
+#ifndef CONFIG_GNRC_TCP_RTO_K
+#define CONFIG_GNRC_TCP_RTO_K (4U)
 #endif
 
 /**
  * @brief Lower bound for the duration between probes
  */
-#ifndef GNRC_TCP_PROBE_LOWER_BOUND
-#define GNRC_TCP_PROBE_LOWER_BOUND (1U * US_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_PROBE_LOWER_BOUND
+#define CONFIG_GNRC_TCP_PROBE_LOWER_BOUND (1U * US_PER_SEC)
 #endif
 
 /**
  * @brief Upper bound for the duration between probes
  */
-#ifndef GNRC_TCP_PROBE_UPPER_BOUND
-#define GNRC_TCP_PROBE_UPPER_BOUND (60U * US_PER_SEC)
+#ifndef CONFIG_GNRC_TCP_PROBE_UPPER_BOUND
+#define CONFIG_GNRC_TCP_PROBE_UPPER_BOUND (60U * US_PER_SEC)
 #endif
+/** @} */
 
 #ifdef __cplusplus
 }

sys/net/gnrc/Kconfig

@@ -13,5 +13,6 @@ rsource "netif/Kconfig"
 rsource "network_layer/ipv6/Kconfig"
 rsource "network_layer/sixlowpan/Kconfig"
 rsource "routing/rpl/Kconfig"
+rsource "transport_layer/tcp/Kconfig"
 
 endmenu # GNRC Network Stack

sys/net/gnrc/transport_layer/tcp/Kconfig

@@ -0,0 +1,115 @@
+# Copyright (c) 2020 Freie Universitaet Berlin
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+#
+menuconfig KCONFIG_MODULE_GNRC_TCP
+    bool "Configure GNRC_TCP"
+    depends on MODULE_GNRC_TCP
+    help
+        Configure the GNRC_TCP using Kconfig.
+
+if KCONFIG_MODULE_GNRC_TCP
+
+config GNRC_TCP_CONNECTION_TIMEOUT_DURATION
+    int "Timeout duration for user calls in microseconds"
+    default 120000000
+    help
+        Timeout duration for user calls. Default value is 120000000 microseconds
+        (2 minutes).
+
+config GNRC_TCP_MSL
+    int "Maximum segment lifetime (MSL) in microseconds"
+    default 30000000
+    help
+        Maximum segment lifetime (MSL) in microseconds. Default value is 30
+        seconds.
+
+config GNRC_TCP_MSS
+    int "Maximum Segment Size (MSS)"
+    default 1220 if MODULE_GNRC_IPV6
+    default 576
+
+config GNRC_TCP_MSS_MULTIPLICATOR
+    int "Number of MSS sized packets stored in receive buffer"
+    default 1
+    help
+        Configure MSS Multiplicator i.e. number of MSS sized packets stored in
+        receive buffer.
+
+config GNRC_TCP_DEFAULT_WINDOW_EN
+    bool "Enable configuration of TCP window size"
+    help
+        Enable configuration of TCP window size. If not enabled, TCP window size
+        will default to the product of Maximum Segment Size and the number of
+        MSS sized packets i.e. CONFIG_GNRC_TCP_MSS *
+        CONFIG_GNRC_TCP_MSS_MULTIPLICATOR.
+
+config GNRC_TCP_DEFAULT_WINDOW
+    int "TCP receive window size"
+    default 1220 if MODULE_GNRC_IPV6
+    default 576
+    depends on GNRC_TCP_DEFAULT_WINDOW_EN
+    help
+        Configure TCP receive window size. This value determines the maximum
+        amount of bytes that can be received from the peer at a given moment.
+
+config GNRC_TCP_RCV_BUFFERS
+    int "Number of preallocated receive buffers"
+    default 1
+
+config GNRC_TCP_RTO_LOWER_BOUND
+    int "Lower bound for RTO in microseconds"
+    default 1000000
+    help
+        Lower bound value for retransmission timeout (RTO) in microseconds.
+        Default value is 1000000 microseconds (1 second). Retransmission
+        timeout determines how long TCP waits for acknowledgment (ACK) of
+        transmitted segment. Refer to RFC 6298 for more information.
+
+config GNRC_TCP_RTO_UPPER_BOUND
+    int "Upper bound for RTO in microseconds"
+    default 60000000
+    help
+        Upper bound value for retransmission timeout (RTO) in microseconds.
+        Default value is 60000000 microseconds (60 seconds). Refer to RFC 6298
+        for more information.
+
+config GNRC_TCP_RTO_GRANULARITY
+    int "Clock granularity for RTO in microseconds"
+    default 10000
+    help
+        Clock granularity for retransmission timeout (RTO) for TCP in
+        microseconds. Default value is 10000 microseconds (10 milliseconds).
+        Refer to RFC 6298 for more information.
+
+config GNRC_TCP_RTO_A_DIV
+    int "Alpha value divisor for RTO calculation"
+    default 8
+    help
+        Alpha value divisor to calculate retransmission timeout (RTO). The
+        default value for divisor is 8 which would result in an alpha value of
+        1/8.
+
+config GNRC_TCP_RTO_B_DIV
+    int "Beta value divisor for RTO calculation"
+    default 4
+    help
+        Beta value divisor to calculate retransmission timeout (RTO). The
+        default value for divisor is 4 which would result in a beta value of
+        1/4.
+
+config GNRC_TCP_RTO_K
+    int "K value for RTO calculation"
+    default 4
+
+config GNRC_TCP_PROBE_LOWER_BOUND
+    int "Lower bound for the duration between probes in microseconds"
+    default 1000000
+
+config GNRC_TCP_PROBE_UPPER_BOUND
+    int "Lower bound for the duration between probes in microseconds"
+    default 60000000
+
+endif # KCONFIG_MODULE_GNRC_TCP

sys/net/gnrc/transport_layer/tcp/gnrc_tcp.c

@@ -186,7 +186,7 @@ static int _gnrc_tcp_open(gnrc_tcp_tcb_t *tcb, const gnrc_tcp_ep_t *remote,
         tcb->peer_port = remote->port;
 
         /* Setup connection timeout: Put timeout message in TCBs mbox on expiration */
-        _setup_timeout(&connection_timeout, GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
+        _setup_timeout(&connection_timeout, CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
                        _cb_mbox_put_msg, &connection_timeout_arg);
     }
 
@@ -211,7 +211,7 @@ static int _gnrc_tcp_open(gnrc_tcp_tcb_t *tcb, const gnrc_tcp_ep_t *remote,
                  * send SYN+ACK we received upon entering SYN_RCVD is never acknowledged
                  * by the peer. */
                 if ((tcb->state == FSM_STATE_SYN_RCVD) && (tcb->status & STATUS_PASSIVE)) {
-                    _setup_timeout(&connection_timeout, GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
+                    _setup_timeout(&connection_timeout, CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
                                    _cb_mbox_put_msg, &connection_timeout_arg);
                 }
                 break;
@@ -493,7 +493,7 @@ ssize_t gnrc_tcp_send(gnrc_tcp_tcb_t *tcb, const void *data, const size_t len,
     }
 
     /* Setup connection timeout: Put timeout message in tcb's mbox on expiration */
-    _setup_timeout(&connection_timeout, GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
+    _setup_timeout(&connection_timeout, CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
                    _cb_mbox_put_msg, &connection_timeout_arg);
 
     /* Setup user specified timeout if timeout_us is greater than zero */
@@ -548,19 +548,19 @@ ssize_t gnrc_tcp_send(gnrc_tcp_tcb_t *tcb, const void *data, const size_t len,
                 probe_timeout_duration_us += probe_timeout_duration_us;
 
                 /* Boundary check for time interval between probes */
-                if (probe_timeout_duration_us < GNRC_TCP_PROBE_LOWER_BOUND) {
-                    probe_timeout_duration_us = GNRC_TCP_PROBE_LOWER_BOUND;
+                if (probe_timeout_duration_us < CONFIG_GNRC_TCP_PROBE_LOWER_BOUND) {
+                    probe_timeout_duration_us = CONFIG_GNRC_TCP_PROBE_LOWER_BOUND;
                 }
-                else if (probe_timeout_duration_us > GNRC_TCP_PROBE_UPPER_BOUND) {
-                    probe_timeout_duration_us = GNRC_TCP_PROBE_UPPER_BOUND;
+                else if (probe_timeout_duration_us > CONFIG_GNRC_TCP_PROBE_UPPER_BOUND) {
+                    probe_timeout_duration_us = CONFIG_GNRC_TCP_PROBE_UPPER_BOUND;
                 }
                 break;
 
             case MSG_TYPE_NOTIFY_USER:
                 DEBUG("gnrc_tcp.c : gnrc_tcp_send() : NOTIFY_USER\n");
 
                 /* Connection is alive: Reset Connection Timeout */
-                _setup_timeout(&connection_timeout, GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
+                _setup_timeout(&connection_timeout, CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
                                _cb_mbox_put_msg, &connection_timeout_arg);
 
                 /* If the window re-opened and we are probing: Stop it */
@@ -633,7 +633,7 @@ ssize_t gnrc_tcp_recv(gnrc_tcp_tcb_t *tcb, void *data, const size_t max_len,
     }
 
     /* Setup connection timeout: Put timeout message in tcb's mbox on expiration */
-    _setup_timeout(&connection_timeout, GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
+    _setup_timeout(&connection_timeout, CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
                    _cb_mbox_put_msg, &connection_timeout_arg);
 
     /* Setup user specified timeout */
@@ -714,7 +714,7 @@ void gnrc_tcp_close(gnrc_tcp_tcb_t *tcb)
     }
 
     /* Setup connection timeout: Put timeout message in tcb's mbox on expiration */
-    _setup_timeout(&connection_timeout, GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
+    _setup_timeout(&connection_timeout, CONFIG_GNRC_TCP_CONNECTION_TIMEOUT_DURATION,
                    _cb_mbox_put_msg, &connection_timeout_arg);
 
     /* Start connection teardown sequence */