Return-Path: From: Jonah Petri Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) Subject: [PATCH] gatt-server: Implement NegotiatedMTU property on Device1 Message-Id: Date: Fri, 14 Jul 2017 11:56:03 -0400 To: linux-bluetooth@vger.kernel.org Sender: linux-bluetooth-owner@vger.kernel.org List-ID: It can be useful for programs using GATT to be aware of the maximum transmittable packet size, as negotiated by bluetoothd. This change exposes the negotiated MTU over D-Bus, if such a negotiation has occurred. --- client/main.c | 1 + doc/device-api.txt | 5 +++++ src/device.c | 31 +++++++++++++++++++++++++++++++ src/shared/gatt-server.c | 15 +++++++++++++++ src/shared/gatt-server.h | 3 +++ 5 files changed, 55 insertions(+) diff --git a/client/main.c b/client/main.c index 255cbd5..6435674 100644 --- a/client/main.c +++ b/client/main.c @@ -1372,6 +1372,7 @@ static void cmd_info(const char *arg) print_property(proxy, "ServiceData"); print_property(proxy, "RSSI"); print_property(proxy, "TxPower"); + print_property(proxy, "NegotiatedMTU"); } =20 static void pair_reply(DBusMessage *message, void *user_data) diff --git a/doc/device-api.txt b/doc/device-api.txt index 13b2881..908616b 100644 --- a/doc/device-api.txt +++ b/doc/device-api.txt @@ -234,3 +234,8 @@ Properties string Address [readonly] array{byte} AdvertisingFlags [readonly, experimental] =20 The Advertising Data Flags of the remote device. + + int16 NegotiatedMTU [readonly, optional, experimental] + + The ATT MTU negotiated with the connected host. + Available only once MTU negotiation is complete. diff --git a/src/device.c b/src/device.c index 8693eb8..1b171ee 100644 --- a/src/device.c +++ b/src/device.c @@ -930,6 +930,35 @@ static gboolean dev_property_exists_tx_power(const = GDBusPropertyTable *property, return TRUE; } =20 +static gboolean dev_property_get_negotiated_mtu( + const GDBusPropertyTable * = property, + DBusMessageIter *iter, void = *data) +{ + const struct btd_device *dev =3D data; + dbus_int16_t val =3D 0; + int err; + + err =3D bt_gatt_server_get_negotiated_mtu(dev->server, &val); + if (err !=3D 0) + return FALSE; + + dbus_message_iter_append_basic(iter, DBUS_TYPE_INT16, &val); + + return TRUE; +} + +static gboolean dev_property_exists_negotiated_mtu( + const GDBusPropertyTable * = property, + void *data) +{ + const struct btd_device *dev =3D data; + int err; + + err =3D bt_gatt_server_get_negotiated_mtu(dev->server, NULL); + + return err =3D=3D 0; +} + static gboolean dev_property_get_svc_resolved(const GDBusPropertyTable *property, DBusMessageIter *iter, void = *data) @@ -2561,6 +2590,8 @@ static const GDBusPropertyTable = device_properties[] =3D { NULL, dev_property_service_data_exist }, { "TxPower", "n", dev_property_get_tx_power, NULL, dev_property_exists_tx_power }, + { "NegotiatedMTU", "n", dev_property_get_negotiated_mtu, NULL, + = dev_property_exists_negotiated_mtu }, { "ServicesResolved", "b", dev_property_get_svc_resolved, NULL, = NULL }, { "AdvertisingFlags", "ay", dev_property_get_flags, NULL, dev_property_flags_exist, diff --git a/src/shared/gatt-server.c b/src/shared/gatt-server.c index 79e01c8..2727f09 100644 --- a/src/shared/gatt-server.c +++ b/src/shared/gatt-server.c @@ -89,6 +89,7 @@ struct bt_gatt_server { struct bt_att *att; int ref_count; uint16_t mtu; + bool mtu_negotiated; =20 unsigned int mtu_id; unsigned int read_by_grp_type_id; @@ -1378,12 +1379,25 @@ static void exchange_mtu_cb(uint8_t opcode, = const void *pdu, =20 /* Set MTU to be the minimum */ server->mtu =3D final_mtu; + server->mtu_negotiated =3D true; bt_att_set_mtu(server->att, final_mtu); =20 util_debug(server->debug_callback, server->debug_data, "MTU exchange complete, with MTU: %u", = final_mtu); } =20 +int bt_gatt_server_get_negotiated_mtu(const struct bt_gatt_server = *server, + int16_t *mtu) +{ + if (!server || !server->mtu_negotiated) + return -1; + + if (mtu) + *mtu =3D server->mtu; + + return 0; +} + static bool gatt_server_register_att_handlers(struct bt_gatt_server = *server) { /* Exchange MTU */ @@ -1493,6 +1507,7 @@ struct bt_gatt_server *bt_gatt_server_new(struct = gatt_db *db, server->db =3D gatt_db_ref(db); server->att =3D bt_att_ref(att); server->mtu =3D MAX(mtu, BT_ATT_DEFAULT_LE_MTU); + server->mtu_negotiated =3D false; server->max_prep_queue_len =3D DEFAULT_MAX_PREP_QUEUE_LEN; server->prep_queue =3D queue_new(); =20 diff --git a/src/shared/gatt-server.h b/src/shared/gatt-server.h index 0e480e1..0b99da5 100644 --- a/src/shared/gatt-server.h +++ b/src/shared/gatt-server.h @@ -31,6 +31,9 @@ struct bt_gatt_server *bt_gatt_server_new(struct = gatt_db *db, struct bt_gatt_server *bt_gatt_server_ref(struct bt_gatt_server = *server); void bt_gatt_server_unref(struct bt_gatt_server *server); =20 +int bt_gatt_server_get_negotiated_mtu(const struct bt_gatt_server = *server, + int16_t *mtu); + typedef void (*bt_gatt_server_destroy_func_t)(void *user_data); typedef void (*bt_gatt_server_debug_func_t)(const char *str, void = *user_data); typedef void (*bt_gatt_server_conf_func_t)(void *user_data); --=20 2.10.0