From dde9ff1e1989698c4502e3c8fea2b7ddfa85caf8 Mon Sep 17 00:00:00 2001
From: Matthias Ringwald <matthias@ringwald.ch>
Date: Tue, 29 Dec 2020 15:12:03 +0100
Subject: [PATCH] gatt_client/att_server: track mtu exchanged in
 hci_connection->att_connection

---
 src/ble/att_db.c      |  1 +
 src/ble/att_db.h      |  1 +
 src/ble/gatt_client.c | 11 ++++++++++-
 src/hci.c             |  6 +++++-
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/ble/att_db.c b/src/ble/att_db.c
index a3d19b3bc..0cd5ba4de 100644
--- a/src/ble/att_db.c
+++ b/src/ble/att_db.c
@@ -369,6 +369,7 @@ static uint16_t handle_exchange_mtu_request(att_connection_t * att_connection, u
     // find min(local max mtu, remote mtu) >= ATT_DEFAULT_MTU and use as mtu for this connection
     uint16_t min_mtu = btstack_min(client_rx_mtu, att_connection->max_mtu);
     uint16_t new_mtu = btstack_max(ATT_DEFAULT_MTU, min_mtu);
+    att_connection->mtu_exchanged = true;
     att_connection->mtu = new_mtu;
 
     response_buffer[0] = ATT_EXCHANGE_MTU_RESPONSE;
diff --git a/src/ble/att_db.h b/src/ble/att_db.h
index 7c36faf81..f12ff993e 100644
--- a/src/ble/att_db.h
+++ b/src/ble/att_db.h
@@ -109,6 +109,7 @@ typedef struct att_connection {
     hci_con_handle_t con_handle;
     uint16_t mtu;       // initialized to ATT_DEFAULT_MTU (23), negotiated during MTU exchange
     uint16_t max_mtu;   // local maximal L2CAP_MTU, set to l2cap_max_le_mtu()
+    bool     mtu_exchanged;
     uint8_t  encryption_key_size;
     uint8_t  authenticated;
     uint8_t  authorized;
diff --git a/src/ble/gatt_client.c b/src/ble/gatt_client.c
index 4c25b8d28..8c8805ecb 100644
--- a/src/ble/gatt_client.c
+++ b/src/ble/gatt_client.c
@@ -1319,8 +1319,17 @@ static void gatt_client_att_packet_handler(uint8_t packet_type, uint16_t handle,
             if (size < 3u) break;
             uint16_t remote_rx_mtu = little_endian_read_16(packet, 1);
             uint16_t local_rx_mtu = l2cap_max_le_mtu();
-            gatt_client->mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
+            uint16_t mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
+
+            // set gatt client mtu
+            gatt_client->mtu = mtu;
             gatt_client->mtu_state = MTU_EXCHANGED;
+
+            // set per connection mtu state
+            hci_connection_t * hci_connection = hci_connection_for_handle(handle);
+            hci_connection->att_connection.mtu = gatt_client->mtu;
+            hci_connection->att_connection.mtu_exchanged = true;
+
             emit_gatt_mtu_exchanged_result_event(gatt_client, gatt_client->mtu);
             break;
         }
diff --git a/src/hci.c b/src/hci.c
index 1c819075c..d1dca9ea0 100644
--- a/src/hci.c
+++ b/src/hci.c
@@ -2221,7 +2221,11 @@ static void event_handle_le_connection_complete(const uint8_t * packet){
 	}
 #endif
 
-	// TODO: store - role, peer address type, conn_interval, conn_latency, supervision timeout, master clock
+    // init unenhanced att bearer mtu
+    conn->att_connection.mtu = ATT_DEFAULT_MTU;
+    conn->att_connection.mtu_exchanged = false;
+
+    // TODO: store - role, peer address type, conn_interval, conn_latency, supervision timeout, master clock
 
 	// restart timer
 	// btstack_run_loop_set_timer(&conn->timeout, HCI_CONNECTION_TIMEOUT_MS);