serial_bt, bluez: support MTU exchange in BLE reception

[libsigrok.git] / src / bt / bt_bluez.c

diff --git a/src/bt/bt_bluez.c b/src/bt/bt_bluez.c
index 71c0dbd4e5b902fbe2126344236c676e816f9548..dc3a2636597dde2a525a1d094e618d255826e42e 100644 (file)
--- a/src/bt/bt_bluez.c
+++ b/src/bt/bt_bluez.c
@@ -97,9 +97,6 @@
 #define CONNECT_RFCOMM_TRIES   3
 #define CONNECT_RFCOMM_RETRY_MS        100
 
-/* Silence warning about (currently) unused routine. */
-#define WITH_WRITE_TYPE_HANDLE 0
-
 /* {{{ compat decls */
 /*
  * The availability of conversion helpers in <bluetooth/bluetooth.h>
@@ -240,6 +237,7 @@ struct sr_bt_desc {
        uint16_t write_handle;
        uint16_t cccd_handle;
        uint16_t cccd_value;
+       uint16_t ble_mtu;
        /* Internal state. */
        int devid;
        int fd;
@@ -250,10 +248,8 @@ static int sr_bt_desc_open(struct sr_bt_desc *desc, int *id_ref);
 static void sr_bt_desc_close(struct sr_bt_desc *desc);
 static int sr_bt_check_socket_usable(struct sr_bt_desc *desc);
 static ssize_t sr_bt_write_type(struct sr_bt_desc *desc, uint8_t type);
-#if WITH_WRITE_TYPE_HANDLE
 static ssize_t sr_bt_write_type_handle(struct sr_bt_desc *desc,
        uint8_t type, uint16_t handle);
-#endif
 static ssize_t sr_bt_write_type_handle_bytes(struct sr_bt_desc *desc,
        uint8_t type, uint16_t handle, const uint8_t *data, size_t len);
 static ssize_t sr_bt_char_write_req(struct sr_bt_desc *desc,
@@ -366,7 +362,8 @@ SR_PRIV int sr_bt_config_rfcomm(struct sr_bt_desc *desc, size_t channel)
 
 SR_PRIV int sr_bt_config_notify(struct sr_bt_desc *desc,
        uint16_t read_handle, uint16_t write_handle,
-       uint16_t cccd_handle, uint16_t cccd_value)
+       uint16_t cccd_handle, uint16_t cccd_value,
+       uint16_t ble_mtu)
 {
 
        if (!desc)
@@ -376,6 +373,7 @@ SR_PRIV int sr_bt_config_notify(struct sr_bt_desc *desc,
        desc->write_handle = write_handle;
        desc->cccd_handle = cccd_handle;
        desc->cccd_value = cccd_value;
+       desc->ble_mtu = ble_mtu;
 
        return 0;
 }
@@ -911,6 +909,7 @@ SR_PRIV int sr_bt_check_notify(struct sr_bt_desc *desc)
        size_t packet_dlen;
        const char *type_text;
        int ret;
+       uint16_t mtu;
 
        if (!desc)
                return -1;
@@ -968,6 +967,23 @@ SR_PRIV int sr_bt_check_notify(struct sr_bt_desc *desc)
 
        /* Dispatch according to the message type. */
        switch (packet_type) {
+       case BLE_ATT_EXCHANGE_MTU_REQ:
+               type_text = "MTU exchange request";
+               if (buflen < sizeof(uint16_t)) {
+                       sr_dbg("%s, invalid (size)", type_text);
+                       break;
+               }
+               mtu = read_u16le_inc_len(&bufptr, &buflen);
+               sr_dbg("%s, peripheral value %" PRIu16, type_text, mtu);
+               if (desc->ble_mtu) {
+                       mtu = desc->ble_mtu;
+                       sr_dbg("%s, central value %" PRIu16, type_text, mtu);
+                       sr_bt_write_type_handle(desc,
+                               BLE_ATT_EXCHANGE_MTU_RESP, mtu);
+                       break;
+               }
+               sr_warn("Unhandled BLE %s.", type_text);
+               break;
        case BLE_ATT_ERROR_RESP:
                type_text = "error response";
                if (!buflen) {
@@ -1057,13 +1073,11 @@ static ssize_t sr_bt_write_type(struct sr_bt_desc *desc, uint8_t type)
        return 0;
 }
 
-#if WITH_WRITE_TYPE_HANDLE
 static ssize_t sr_bt_write_type_handle(struct sr_bt_desc *desc,
        uint8_t type, uint16_t handle)
 {
        return sr_bt_write_type_handle_bytes(desc, type, handle, NULL, 0);
 }
-#endif
 
 static ssize_t sr_bt_write_type_handle_bytes(struct sr_bt_desc *desc,
        uint8_t type, uint16_t handle, const uint8_t *data, size_t len)