[nrf fromlist] Bluetooth: Tester: Use BT_L2CAP_SEG_RECV for L2CAP tests

This API gives better control on L2CAP COC credits and suits better
for Upper Tester implementation.

Upstream PR #: 80911

Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>

Author: sjanc

include/zephyr/bluetooth/l2cap.h

@@ -18,6 +18,7 @@
  * @{
  */
 
+#include <stdint.h>
 #include <sys/types.h>
 
 #include <zephyr/sys/atomic.h>
@@ -552,6 +553,26 @@ int bt_l2cap_ecred_chan_connect(struct bt_conn *conn,
  */
 int bt_l2cap_ecred_chan_reconfigure(struct bt_l2cap_chan **chans, uint16_t mtu);
 
+/** @brief Reconfigure Enhanced Credit Based L2CAP channels
+ *
+ *  Experimental API to reconfigure with explicit MPS and MTU values.
+ *
+ *  Reconfigure up to 5 L2CAP channels. Channels must be from the same bt_conn.
+ *  Once reconfiguration is completed each channel reconfigured() callback will
+ *  be called. MTU cannot be decreased on any of provided channels.
+ *
+ *  @kconfig_dep{CONFIG_BT_L2CAP_RECONFIGURE_EXPLICIT}
+ *
+ *  @param chans Array of channel objects. Null-terminated. Elements after the
+ *               first 5 are silently ignored.
+ *  @param mtu Channel MTU to reconfigure to.
+ *  @param mps Channel MPS to reconfigure to.
+ *
+ *  @return 0 in case of success or negative value in case of error.
+ */
+int bt_l2cap_ecred_chan_reconfigure_explicit(struct bt_l2cap_chan **chans, uint16_t mtu,
+					     uint16_t mps);
+
 /** @brief Connect L2CAP channel
  *
  *  Connect L2CAP channel by PSM, once the connection is completed channel

subsys/bluetooth/host/Kconfig.l2cap

@@ -70,4 +70,12 @@ config BT_L2CAP_SEG_RECV
 	  This API enforces conformance with L2CAP TS, but is otherwise as
 	  flexible and semantically simple as possible.
 
+config BT_L2CAP_RECONFIGURE_EXPLICIT
+	bool "L2CAP Explicit reconfigure API [EXPERIMENTAL]"
+	select EXPERIMENTAL
+	help
+
+	  Enable API for explicit reconfiguration of an L2CAP channel's MTU and
+	  MPS.
+
 endmenu

subsys/bluetooth/host/l2cap.c

@@ -41,6 +41,7 @@ LOG_MODULE_REGISTER(bt_l2cap, CONFIG_BT_L2CAP_LOG_LEVEL);
 
 #define L2CAP_LE_MIN_MTU		23
 #define L2CAP_ECRED_MIN_MTU		64
+#define L2CAP_ECRED_MIN_MPS             64
 
 #define L2CAP_LE_MAX_CREDITS		(CONFIG_BT_BUF_ACL_RX_COUNT - 1)
 
@@ -3032,6 +3033,105 @@ int bt_l2cap_ecred_chan_reconfigure(struct bt_l2cap_chan **chans, uint16_t mtu)
 	return 0;
 }
 
+#if defined(CONFIG_BT_L2CAP_RECONFIGURE_EXPLICIT)
+int bt_l2cap_ecred_chan_reconfigure_explicit(struct bt_l2cap_chan **chans, uint16_t mtu,
+					     uint16_t mps)
+{
+	struct bt_l2cap_ecred_reconf_req *req;
+	struct bt_conn *conn = NULL;
+	struct bt_l2cap_le_chan *ch;
+	struct net_buf *buf;
+	bool multiple_chan;
+	uint8_t ident;
+	int i;
+
+	LOG_DBG("chans %p mtu 0x%04x mps 0x%04x", chans, mtu, mps);
+
+	if (!chans) {
+		return -EINVAL;
+	}
+
+	if (chans[0] == NULL) {
+		return -EINVAL;
+	}
+
+	if (mps < L2CAP_ECRED_MIN_MPS || mps > BT_L2CAP_RX_MTU) {
+		return -EINVAL;
+	}
+
+	multiple_chan = chans[1] != NULL;
+
+	for (i = 0; i < L2CAP_ECRED_CHAN_MAX_PER_REQ; i++) {
+		if (!chans[i]) {
+			break;
+		}
+
+		/* validate that all channels are from same connection */
+		if (conn) {
+			if (conn != chans[i]->conn) {
+				return -EINVAL;
+			}
+		} else {
+			conn = chans[i]->conn;
+		}
+
+		/* validate MTU is not decreased */
+		if (mtu < BT_L2CAP_LE_CHAN(chans[i])->rx.mtu) {
+			return -EINVAL;
+		}
+
+		/* MPS is not allowed to decrease when reconfiguring multiple channels.
+		 * Core Specification 3.A.4.27 v6.0
+		 */
+		if (multiple_chan && mps < BT_L2CAP_LE_CHAN(chans[i])->rx.mps) {
+			return -EINVAL;
+		}
+	}
+
+	if (!conn) {
+		return -ENOTCONN;
+	}
+
+	if (conn->type != BT_CONN_TYPE_LE) {
+		return -EINVAL;
+	}
+
+	/* allow only 1 request at time */
+	if (l2cap_find_pending_reconf(conn)) {
+		return -EBUSY;
+	}
+
+	ident = get_ident();
+
+	buf = l2cap_create_le_sig_pdu(BT_L2CAP_ECRED_RECONF_REQ, ident,
+				      sizeof(*req) + (i * sizeof(uint16_t)));
+	if (!buf) {
+		return -ENOMEM;
+	}
+
+	req = net_buf_add(buf, sizeof(*req));
+	req->mtu = sys_cpu_to_le16(mtu);
+	req->mps = sys_cpu_to_le16(mps);
+
+	for (int j = 0; j < i; j++) {
+		ch = BT_L2CAP_LE_CHAN(chans[j]);
+
+		ch->ident = ident;
+		ch->pending_rx_mtu = mtu;
+
+		net_buf_add_le16(buf, ch->rx.cid);
+	};
+
+	/* We set the RTX timer on one of the supplied channels, but when the
+	 * request resolves or times out we will act on all the channels in the
+	 * supplied array, using the ident field to find them.
+	 */
+	l2cap_chan_send_req(chans[0], buf, L2CAP_CONN_TIMEOUT);
+
+	return 0;
+}
+#endif /* defined(CONFIG_BT_L2CAP_RECONFIGURE_EXPLICIT) */
+
 #endif /* defined(CONFIG_BT_L2CAP_ECRED) */
 
 int bt_l2cap_chan_connect(struct bt_conn *conn, struct bt_l2cap_chan *chan,

tests/bluetooth/tester/prj.conf

@@ -16,6 +16,8 @@ CONFIG_BT_BONDABLE=y
 CONFIG_BT_ATT_PREPARE_COUNT=12
 CONFIG_BT_GATT_CLIENT=y
 CONFIG_BT_L2CAP_DYNAMIC_CHANNEL=y
+CONFIG_BT_L2CAP_SEG_RECV=y
+CONFIG_BT_L2CAP_RECONFIGURE_EXPLICIT=y
 CONFIG_BT_DEVICE_NAME="Tester"
 CONFIG_BT_DEVICE_NAME_MAX=32
 CONFIG_BT_DEVICE_NAME_DYNAMIC=y
@@ -33,7 +35,6 @@ CONFIG_BT_GATT_DYNAMIC_DB=y
 CONFIG_BT_EXT_ADV=y
 CONFIG_BT_PER_ADV=y
 CONFIG_BT_PER_ADV_SYNC=y
-CONFIG_BT_BUF_ACL_RX_SIZE=100
 CONFIG_BT_RX_STACK_SIZE=4096
 
 CONFIG_BT_TESTING=y

tests/bluetooth/tester/src/btp_l2cap.c

@@ -19,14 +19,15 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME, CONFIG_BTTESTER_LOG_LEVEL);
 
 #include "btp/btp.h"
 
-#define DATA_MTU_INITIAL 128
-#define DATA_MTU 256
-#define DATA_BUF_SIZE BT_L2CAP_SDU_BUF_SIZE(DATA_MTU)
+#define L2CAP_MPS        96
+#define DATA_MTU         (3 * L2CAP_MPS)
+#define DATA_MTU_INITIAL (2 * L2CAP_MPS)
+
 #define CHANNELS 2
 #define SERVERS 1
 
-NET_BUF_POOL_FIXED_DEFINE(data_pool, CHANNELS, DATA_BUF_SIZE, CONFIG_BT_CONN_TX_USER_DATA_SIZE,
-			  NULL);
+NET_BUF_POOL_FIXED_DEFINE(data_pool, CHANNELS, BT_L2CAP_SDU_BUF_SIZE(DATA_MTU),
+			  CONFIG_BT_CONN_TX_USER_DATA_SIZE, NULL);
 
 static bool authorize_flag;
 static uint8_t req_keysize;
@@ -36,18 +37,51 @@ static struct channel {
 	struct bt_l2cap_le_chan le;
 	bool in_use;
 	bool hold_credit;
+#if defined(CONFIG_BT_L2CAP_SEG_RECV)
+	unsigned int pending_credits;
+	uint8_t recv_cb_buf[DATA_MTU + sizeof(struct btp_l2cap_data_received_ev)];
+#else
 	struct net_buf *pending_credit;
+#endif
 } channels[CHANNELS];
 
 /* TODO Extend to support multiple servers */
 static struct bt_l2cap_server servers[SERVERS];
 
+#if defined(CONFIG_BT_L2CAP_SEG_RECV)
+static void seg_recv_cb(struct bt_l2cap_chan *l2cap_chan, size_t sdu_len, off_t seg_offset,
+			struct net_buf_simple *seg)
+{
+	struct btp_l2cap_data_received_ev *ev;
+	struct bt_l2cap_le_chan *l2cap_le_chan =
+		CONTAINER_OF(l2cap_chan, struct bt_l2cap_le_chan, chan);
+	struct channel *chan = CONTAINER_OF(l2cap_le_chan, struct channel, le);
+
+	ev = (void *)chan->recv_cb_buf;
+	memcpy(&ev->data[seg_offset], seg->data, seg->len);
+
+	/* complete SDU received */
+	if (seg_offset + seg->len == sdu_len) {
+		ev->chan_id = chan->chan_id;
+		ev->data_length = sys_cpu_to_le16(sdu_len);
+
+		tester_event(BTP_SERVICE_ID_L2CAP, BTP_L2CAP_EV_DATA_RECEIVED, chan->recv_cb_buf,
+			     sizeof(*ev) + sdu_len);
+	}
+
+	if (chan->hold_credit) {
+		chan->pending_credits++;
+	} else {
+		bt_l2cap_chan_give_credits(l2cap_chan, 1);
+	}
+}
+#else
 static struct net_buf *alloc_buf_cb(struct bt_l2cap_chan *chan)
 {
 	return net_buf_alloc(&data_pool, K_FOREVER);
 }
 
-static uint8_t recv_cb_buf[DATA_BUF_SIZE + sizeof(struct btp_l2cap_data_received_ev)];
+static uint8_t recv_cb_buf[DATA_MTU + sizeof(struct btp_l2cap_data_received_ev)];
 
 static int recv_cb(struct bt_l2cap_chan *l2cap_chan, struct net_buf *buf)
 {
@@ -73,6 +107,7 @@ static int recv_cb(struct bt_l2cap_chan *l2cap_chan, struct net_buf *buf)
 
 	return 0;
 }
+#endif
 
 static void connected_cb(struct bt_l2cap_chan *l2cap_chan)
 {
@@ -111,11 +146,13 @@ static void disconnected_cb(struct bt_l2cap_chan *l2cap_chan)
 	struct channel *chan = CONTAINER_OF(l2cap_le_chan, struct channel, le);
 	struct bt_conn_info info;
 
+#if !defined(CONFIG_BT_L2CAP_SEG_RECV)
 	/* release netbuf on premature disconnection */
 	if (chan->pending_credit) {
 		net_buf_unref(chan->pending_credit);
 		chan->pending_credit = NULL;
 	}
+#endif
 
 	(void)memset(&ev, 0, sizeof(struct btp_l2cap_disconnected_ev));
 
@@ -160,12 +197,16 @@ static void reconfigured_cb(struct bt_l2cap_chan *l2cap_chan)
 #endif
 
 static const struct bt_l2cap_chan_ops l2cap_ops = {
-	.alloc_buf	= alloc_buf_cb,
-	.recv		= recv_cb,
-	.connected	= connected_cb,
-	.disconnected	= disconnected_cb,
+#if defined(CONFIG_BT_L2CAP_SEG_RECV)
+	.seg_recv = seg_recv_cb,
+#else
+	.alloc_buf = alloc_buf_cb,
+	.recv = recv_cb,
+#endif
+	.connected = connected_cb,
+	.disconnected = disconnected_cb,
 #if defined(CONFIG_BT_L2CAP_ECRED)
-	.reconfigured	= reconfigured_cb,
+	.reconfigured = reconfigured_cb,
 #endif
 };
 
@@ -222,10 +263,15 @@ static uint8_t connect(const void *cmd, uint16_t cmd_len,
 		}
 		chan->le.chan.ops = &l2cap_ops;
 		chan->le.rx.mtu = mtu;
+#if defined(CONFIG_BT_L2CAP_SEG_RECV)
+		chan->le.rx.mps = L2CAP_MPS;
+#endif
 		rp->chan_id[i] = chan->chan_id;
 		allocated_channels[i] = &chan->le.chan;
 
 		chan->hold_credit = cp->options & BTP_L2CAP_CONNECT_OPT_HOLD_CREDIT;
+
+		bt_l2cap_chan_give_credits(&chan->le.chan, 1);
 	}
 
 	if (cp->num == 1 && !ecfc) {
@@ -289,6 +335,7 @@ static uint8_t reconfigure(const void *cmd, uint16_t cmd_len,
 {
 	const struct btp_l2cap_reconfigure_cmd *cp = cmd;
 	uint16_t mtu;
+	uint16_t mps;
 	struct bt_conn *conn;
 	int err;
 	struct bt_l2cap_chan *reconf_channels[CHANNELS + 1] = {};
@@ -321,7 +368,8 @@ static uint8_t reconfigure(const void *cmd, uint16_t cmd_len,
 		return BTP_STATUS_FAILED;
 	}
 
-	err = bt_l2cap_ecred_chan_reconfigure(reconf_channels, mtu);
+	mps = MIN(L2CAP_MPS, BT_L2CAP_RX_MTU);
+	err = bt_l2cap_ecred_chan_reconfigure_explicit(reconf_channels, mtu, mps);
 	if (err) {
 		bt_conn_unref(conn);
 		return BTP_STATUS_FAILED;
@@ -454,9 +502,14 @@ static int accept(struct bt_conn *conn, struct bt_l2cap_server *server,
 
 	chan->le.chan.ops = &l2cap_ops;
 	chan->le.rx.mtu = DATA_MTU_INITIAL;
+#if defined(CONFIG_BT_L2CAP_SEG_RECV)
+	chan->le.rx.mps = L2CAP_MPS;
+#endif
 
 	*l2cap_chan = &chan->le.chan;
 
+	bt_l2cap_chan_give_credits(&chan->le.chan, 1);
+
 	return 0;
 }
 
@@ -524,7 +577,15 @@ static uint8_t credits(const void *cmd, uint16_t cmd_len,
 	if (!chan->in_use) {
 		return BTP_STATUS_FAILED;
 	}
+#if defined(CONFIG_BT_L2CAP_SEG_RECV)
+	if (chan->pending_credits) {
+		if (bt_l2cap_chan_give_credits(&chan->le.chan, chan->pending_credits) < 0) {
+			return BTP_STATUS_FAILED;
+		}
 
+		chan->pending_credits = 0;
+	}
+#else
 	if (chan->pending_credit) {
 		if (bt_l2cap_chan_recv_complete(&chan->le.chan,
 						chan->pending_credit) < 0) {
@@ -533,6 +594,7 @@ static uint8_t credits(const void *cmd, uint16_t cmd_len,
 
 		chan->pending_credit = NULL;
 	}
+#endif
 
 	return BTP_STATUS_SUCCESS;
 }