This helper makes code easier to follow. Also local MTU is now
MIN(IMTU,OMTU) to avoid situation that where local OMTU is
lower than negotiated MTU.
---
android/gatt.c | 97 ++++++++++++++++++++++++++++------------------------------
1 file changed, 46 insertions(+), 51 deletions(-)
diff --git a/android/gatt.c b/android/gatt.c
index 45d70fd..d5f3d7d 100644
--- a/android/gatt.c
+++ b/android/gatt.c
@@ -954,15 +954,38 @@ static gboolean disconnected_cb(GIOChannel *io, GIOCondition cond,
return FALSE;
}
+static bool get_local_mtu(struct gatt_device *dev, uint16_t *mtu)
+{
+ GIOChannel *io;
+ uint16_t imtu, omtu;
+
+ io = g_attrib_get_channel(dev->attrib);
+
+ if (!bt_io_get(io, NULL, BT_IO_OPT_IMTU, &imtu, BT_IO_OPT_OMTU, &omtu,
+ BT_IO_OPT_INVALID)) {
+ error("gatt: Failed to get local MTU");
+ return false;
+ }
+
+ /*
+ * Limit MTU to MIN(IMTU, OMTU). This is to avoid situation where
+ * local OMTU < MIN(remote MTU, IMTU)
+ */
+ if (mtu)
+ *mtu = MIN(imtu, omtu);
+
+ DBG("mtu %u", *mtu);
+
+ return true;
+}
+
static void att_handler(const uint8_t *ipdu, uint16_t len, gpointer user_data);
static void exchange_mtu_cb(guint8 status, const guint8 *pdu, guint16 plen,
gpointer user_data)
{
struct gatt_device *device = user_data;
- GIOChannel *io;
- GError *gerr = NULL;
- uint16_t rmtu, mtu, imtu;
+ uint16_t rmtu, lmtu, mtu;
if (status) {
error("gatt: MTU exchange: %s", att_ecode2str(status));
@@ -975,28 +998,22 @@ static void exchange_mtu_cb(guint8 status, const guint8 *pdu, guint16 plen,
}
if (rmtu < ATT_DEFAULT_LE_MTU) {
- error("gatt: MTU exchange: mtu error");
+ error("gatt: MTU exchange: remote MTU invalid (%u)", rmtu);
goto failed;
}
- io = g_attrib_get_channel(device->attrib);
+ if (!get_local_mtu(device, &lmtu))
+ goto failed;
- bt_io_get(io, &gerr, BT_IO_OPT_IMTU, &imtu, BT_IO_OPT_INVALID);
- if (gerr) {
- error("gatt: Could not get imtu: %s", gerr->message);
- g_error_free(gerr);
+ mtu = MIN(lmtu, rmtu);
- return;
- }
-
- mtu = MIN(rmtu, imtu);
- if (mtu != imtu && !g_attrib_set_mtu(device->attrib, mtu)) {
+ if (mtu != ATT_DEFAULT_LE_MTU &&
+ !g_attrib_set_mtu(device->attrib, mtu)) {
error("gatt: MTU exchange failed");
goto failed;
}
- DBG("MTU exchange succeeded: rmtu:%d, old mtu:%d, new mtu:%d", rmtu,
- imtu, mtu);
+ DBG("MTU exchange succeeded: remote mtu:%d local mtu:%d", rmtu, lmtu);
failed:
device_unref(device);
@@ -1004,21 +1021,12 @@ failed:
static void send_exchange_mtu_request(struct gatt_device *device)
{
- GIOChannel *io;
- GError *gerr = NULL;
- uint16_t imtu;
-
- io = g_attrib_get_channel(device->attrib);
-
- bt_io_get(io, &gerr, BT_IO_OPT_IMTU, &imtu, BT_IO_OPT_INVALID);
- if (gerr) {
- error("gatt: Could not get imtu: %s", gerr->message);
- g_error_free(gerr);
+ uint16_t mtu;
+ if (!get_local_mtu(device, &mtu))
return;
- }
- if (!gatt_exchange_mtu(device->attrib, imtu, exchange_mtu_cb,
+ if (!gatt_exchange_mtu(device->attrib, mtu, exchange_mtu_cb,
device_ref(device)))
device_unref(device);
}
@@ -6131,50 +6139,37 @@ static uint8_t read_request(const uint8_t *cmd, uint16_t cmd_len,
static uint8_t mtu_att_handle(const uint8_t *cmd, uint16_t cmd_len,
struct gatt_device *dev)
{
- uint16_t mtu, imtu, omtu, cid;
+ uint16_t rmtu, mtu, len;
size_t length;
- GIOChannel *io;
- GError *gerr = NULL;
- uint16_t len;
uint8_t *rsp;
DBG("");
- len = dec_mtu_req(cmd, cmd_len, &mtu);
+ len = dec_mtu_req(cmd, cmd_len, &rmtu);
if (!len)
return ATT_ECODE_INVALID_PDU;
- if (mtu < ATT_DEFAULT_LE_MTU)
+ if (rmtu < ATT_DEFAULT_LE_MTU)
return ATT_ECODE_REQ_NOT_SUPP;
- io = g_attrib_get_channel(dev->attrib);
-
- bt_io_get(io, &gerr,
- BT_IO_OPT_CID, &cid,
- BT_IO_OPT_IMTU, &imtu,
- BT_IO_OPT_OMTU, &omtu,
- BT_IO_OPT_INVALID);
- if (gerr) {
- error("bt_io_get: %s", gerr->message);
- g_error_free(gerr);
+ /* MTU exchange shall not be used on BR/EDR - Vol 3. Part G. 4.3.1 */
+ if (get_cid(dev) != ATT_CID)
return ATT_ECODE_UNLIKELY;
- }
- /* MTU exchange shall not be used on BR/EDR - Vol 3. Part G. 4.3.1 */
- if (cid != ATT_CID)
+ if (!get_local_mtu(dev, &mtu))
return ATT_ECODE_UNLIKELY;
rsp = g_attrib_get_buffer(dev->attrib, &length);
- /* Respond with our IMTU */
- len = enc_mtu_resp(imtu, rsp, length);
+ /* Respond with our MTU */
+ len = enc_mtu_resp(mtu, rsp, length);
if (!len)
return ATT_ECODE_UNLIKELY;
g_attrib_send(dev->attrib, 0, rsp, len, NULL, NULL, NULL);
- /* Limit OMTU to received value */
- mtu = MIN(mtu, omtu);
+ /* Limit MTU to received value */
+ mtu = MIN(mtu, rmtu);
g_attrib_set_mtu(dev->attrib, mtu);
return 0;
--
1.9.3
--
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