| /****************************************************************************** |
| * |
| * Copyright (C) 2014 Google, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at: |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| ******************************************************************************/ |
| |
| #define LOG_TAG "bt_l2cap_client" |
| |
| #include <assert.h> |
| #include <string.h> |
| |
| #include "btcore/include/bdaddr.h" |
| #include "gki/common/gki.h" |
| #include "osi/include/allocator.h" |
| #include "osi/include/buffer.h" |
| #include "osi/include/list.h" |
| #include "osi/include/log.h" |
| #include "osi/include/osi.h" |
| #include "stack/include/l2cap_client.h" |
| #include "stack/include/l2c_api.h" |
| |
| struct l2cap_client_t { |
| l2cap_client_callbacks_t callbacks; |
| void *context; |
| |
| uint16_t local_channel_id; |
| uint16_t remote_mtu; |
| bool configured_self; |
| bool configured_peer; |
| bool is_congested; |
| list_t *outbound_fragments; |
| }; |
| |
| static void connect_completed_cb(uint16_t local_channel_id, uint16_t error_code); |
| static void config_request_cb(uint16_t local_channel_id, tL2CAP_CFG_INFO *requested_parameters); |
| static void config_completed_cb(uint16_t local_channel_id, tL2CAP_CFG_INFO *negotiated_parameters); |
| static void disconnect_request_cb(uint16_t local_channel_id, bool ack_required); |
| static void disconnect_completed_cb(uint16_t local_channel_id, uint16_t error_code); |
| static void congestion_cb(uint16_t local_channel_id, bool is_congested); |
| static void read_ready_cb(uint16_t local_channel_id, BT_HDR *packet); |
| static void write_completed_cb(uint16_t local_channel_id, uint16_t packets_completed); |
| |
| static void fragment_packet(l2cap_client_t *client, buffer_t *packet); |
| static void dispatch_fragments(l2cap_client_t *client); |
| static l2cap_client_t *find(uint16_t local_channel_id); |
| |
| // From the Bluetooth Core specification. |
| static const uint16_t L2CAP_MTU_DEFAULT = 672; |
| static const uint16_t L2CAP_MTU_MINIMUM = 48; |
| |
| static const tL2CAP_APPL_INFO l2cap_callbacks = { |
| .pL2CA_ConnectCfm_Cb = connect_completed_cb, |
| .pL2CA_ConfigInd_Cb = config_request_cb, |
| .pL2CA_ConfigCfm_Cb = config_completed_cb, |
| .pL2CA_DisconnectInd_Cb = disconnect_request_cb, |
| .pL2CA_DisconnectCfm_Cb = disconnect_completed_cb, |
| .pL2CA_CongestionStatus_Cb = congestion_cb, |
| .pL2CA_DataInd_Cb = read_ready_cb, |
| .pL2CA_TxComplete_Cb = write_completed_cb, |
| }; |
| |
| static list_t *l2cap_clients; // A list of l2cap_client_t. Container does not own objects. |
| |
| buffer_t *l2cap_buffer_new(size_t size) { |
| buffer_t *buf = buffer_new(size + L2CAP_MIN_OFFSET); |
| buffer_t *slice = NULL; |
| if (buf) |
| slice = buffer_new_slice(buf, size); |
| buffer_free(buf); |
| return slice; |
| } |
| |
| l2cap_client_t *l2cap_client_new(const l2cap_client_callbacks_t *callbacks, void *context) { |
| assert(callbacks != NULL); |
| assert(callbacks->connected != NULL); |
| assert(callbacks->disconnected != NULL); |
| assert(callbacks->read_ready != NULL); |
| assert(callbacks->write_ready != NULL); |
| |
| if (!l2cap_clients) { |
| l2cap_clients = list_new(NULL); |
| if (!l2cap_clients) { |
| LOG_ERROR(LOG_TAG, "%s unable to allocate space for L2CAP client list.", __func__); |
| return NULL; |
| } |
| } |
| |
| l2cap_client_t *ret = (l2cap_client_t *)osi_calloc(sizeof(l2cap_client_t)); |
| if (!ret) { |
| LOG_ERROR(LOG_TAG, "%s unable to allocate L2CAP client.", __func__); |
| goto error; |
| } |
| |
| ret->callbacks = *callbacks; |
| ret->context = context; |
| |
| ret->remote_mtu = L2CAP_MTU_DEFAULT; |
| ret->outbound_fragments = list_new(NULL); |
| if (!ret) { |
| LOG_ERROR(LOG_TAG, "%s unable to allocate outbound L2CAP fragment list.", __func__); |
| goto error; |
| } |
| |
| list_append(l2cap_clients, ret); |
| |
| return ret; |
| |
| error:; |
| osi_free(ret); |
| return NULL; |
| } |
| |
| void l2cap_client_free(l2cap_client_t *client) { |
| if (!client) |
| return; |
| |
| list_remove(l2cap_clients, client); |
| l2cap_client_disconnect(client); |
| list_free(client->outbound_fragments); |
| osi_free(client); |
| } |
| |
| bool l2cap_client_connect(l2cap_client_t *client, const bt_bdaddr_t *remote_bdaddr, uint16_t psm) { |
| assert(client != NULL); |
| assert(remote_bdaddr != NULL); |
| assert(psm != 0); |
| assert(!bdaddr_is_empty(remote_bdaddr)); |
| assert(client->local_channel_id == 0); |
| assert(!client->configured_self); |
| assert(!client->configured_peer); |
| assert(!L2C_INVALID_PSM(psm)); |
| |
| client->local_channel_id = L2CA_ConnectReq(psm, (uint8_t *)remote_bdaddr); |
| if (!client->local_channel_id) { |
| LOG_ERROR(LOG_TAG, "%s unable to create L2CAP connection.", __func__); |
| return false; |
| } |
| |
| L2CA_SetConnectionCallbacks(client->local_channel_id, &l2cap_callbacks); |
| return true; |
| } |
| |
| void l2cap_client_disconnect(l2cap_client_t *client) { |
| assert(client != NULL); |
| |
| if (client->local_channel_id && !L2CA_DisconnectReq(client->local_channel_id)) |
| LOG_ERROR(LOG_TAG, "%s unable to send disconnect message for LCID 0x%04x.", __func__, client->local_channel_id); |
| |
| client->local_channel_id = 0; |
| client->remote_mtu = L2CAP_MTU_DEFAULT; |
| client->configured_self = false; |
| client->configured_peer = false; |
| client->is_congested = false; |
| |
| for (const list_node_t *node = list_begin(client->outbound_fragments); node != list_end(client->outbound_fragments); node = list_next(node)) |
| GKI_freebuf(list_node(node)); |
| |
| list_clear(client->outbound_fragments); |
| } |
| |
| bool l2cap_client_is_connected(const l2cap_client_t *client) { |
| assert(client != NULL); |
| |
| return client->local_channel_id != 0 && client->configured_self && client->configured_peer; |
| } |
| |
| bool l2cap_client_write(l2cap_client_t *client, buffer_t *packet) { |
| assert(client != NULL); |
| assert(packet != NULL); |
| assert(l2cap_client_is_connected(client)); |
| |
| if (client->is_congested) |
| return false; |
| |
| fragment_packet(client, packet); |
| dispatch_fragments(client); |
| return true; |
| } |
| |
| static void connect_completed_cb(uint16_t local_channel_id, uint16_t error_code) { |
| assert(local_channel_id != 0); |
| |
| l2cap_client_t *client = find(local_channel_id); |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client for LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| if (error_code != L2CAP_CONN_OK) { |
| LOG_ERROR(LOG_TAG, "%s error connecting L2CAP channel: %d.", __func__, error_code); |
| client->callbacks.disconnected(client, client->context); |
| return; |
| } |
| |
| // Use default L2CAP parameters. |
| tL2CAP_CFG_INFO desired_parameters = { 0 }; |
| if (!L2CA_ConfigReq(local_channel_id, &desired_parameters)) { |
| LOG_ERROR(LOG_TAG, "%s error sending L2CAP config parameters.", __func__); |
| client->callbacks.disconnected(client, client->context); |
| } |
| } |
| |
| static void config_request_cb(uint16_t local_channel_id, tL2CAP_CFG_INFO *requested_parameters) { |
| tL2CAP_CFG_INFO response = { 0 }; |
| l2cap_client_t *client = find(local_channel_id); |
| |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client matching LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| response.result = L2CAP_CFG_OK; |
| |
| if (requested_parameters->mtu_present) { |
| // Make sure the peer chose an MTU at least as large as the minimum L2CAP MTU defined |
| // by the Bluetooth Core spec. |
| if (requested_parameters->mtu < L2CAP_MTU_MINIMUM) { |
| response.mtu = L2CAP_MTU_MINIMUM; |
| response.mtu_present = true; |
| response.result = L2CAP_CFG_UNACCEPTABLE_PARAMS; |
| } else { |
| client->remote_mtu = requested_parameters->mtu; |
| } |
| } |
| |
| if (requested_parameters->fcr_present) { |
| if (requested_parameters->fcr.mode != L2CAP_FCR_BASIC_MODE) { |
| response.fcr_present = true; |
| response.fcr = requested_parameters->fcr; |
| response.fcr.mode = L2CAP_FCR_BASIC_MODE; |
| response.result = L2CAP_CFG_UNACCEPTABLE_PARAMS; |
| } |
| } |
| |
| if (!L2CA_ConfigRsp(local_channel_id, &response)) { |
| LOG_ERROR(LOG_TAG, "%s unable to send config response for LCID 0x%04x.", __func__, local_channel_id); |
| l2cap_client_disconnect(client); |
| return; |
| } |
| |
| // If we've configured both endpoints, let the listener know we've connected. |
| client->configured_peer = true; |
| if (l2cap_client_is_connected(client)) |
| client->callbacks.connected(client, client->context); |
| } |
| |
| static void config_completed_cb(uint16_t local_channel_id, tL2CAP_CFG_INFO *negotiated_parameters) { |
| l2cap_client_t *client = find(local_channel_id); |
| |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client matching LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| switch (negotiated_parameters->result) { |
| // We'll get another configuration response later. |
| case L2CAP_CFG_PENDING: |
| break; |
| |
| case L2CAP_CFG_UNACCEPTABLE_PARAMS: |
| // TODO: see if we can renegotiate parameters instead of dropping the connection. |
| LOG_WARN(LOG_TAG, "%s dropping L2CAP connection due to unacceptable config parameters.", __func__); |
| l2cap_client_disconnect(client); |
| break; |
| |
| case L2CAP_CFG_OK: |
| // If we've configured both endpoints, let the listener know we've connected. |
| client->configured_self = true; |
| if (l2cap_client_is_connected(client)) |
| client->callbacks.connected(client, client->context); |
| break; |
| |
| // Failure, no further parameter negotiation possible. |
| default: |
| LOG_WARN(LOG_TAG, "%s L2CAP parameter negotiation failed with error code %d.", __func__, negotiated_parameters->result); |
| l2cap_client_disconnect(client); |
| break; |
| } |
| } |
| |
| static void disconnect_request_cb(uint16_t local_channel_id, bool ack_required) { |
| l2cap_client_t *client = find(local_channel_id); |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client with LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| if (ack_required) |
| L2CA_DisconnectRsp(local_channel_id); |
| |
| // We already sent a disconnect response so this LCID is now invalid. |
| client->local_channel_id = 0; |
| l2cap_client_disconnect(client); |
| |
| client->callbacks.disconnected(client, client->context); |
| } |
| |
| static void disconnect_completed_cb(uint16_t local_channel_id, UNUSED_ATTR uint16_t error_code) { |
| assert(local_channel_id != 0); |
| |
| l2cap_client_t *client = find(local_channel_id); |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client with LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| client->local_channel_id = 0; |
| l2cap_client_disconnect(client); |
| |
| client->callbacks.disconnected(client, client->context); |
| } |
| |
| static void congestion_cb(uint16_t local_channel_id, bool is_congested) { |
| assert(local_channel_id != 0); |
| |
| l2cap_client_t *client = find(local_channel_id); |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client matching LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| client->is_congested = is_congested; |
| |
| if (!is_congested) { |
| // If we just decongested, dispatch whatever we have left over in our queue. |
| // Once that's done, if we're still decongested, notify the listener so it |
| // can start writing again. |
| dispatch_fragments(client); |
| if (!client->is_congested) |
| client->callbacks.write_ready(client, client->context); |
| } |
| } |
| |
| static void read_ready_cb(uint16_t local_channel_id, BT_HDR *packet) { |
| assert(local_channel_id != 0); |
| |
| l2cap_client_t *client = find(local_channel_id); |
| if (!client) { |
| LOG_ERROR(LOG_TAG, "%s unable to find L2CAP client matching LCID 0x%04x.", __func__, local_channel_id); |
| return; |
| } |
| |
| // TODO(sharvil): eliminate copy from BT_HDR. |
| buffer_t *buffer = buffer_new(packet->len); |
| memcpy(buffer_ptr(buffer), packet->data + packet->offset, packet->len); |
| GKI_freebuf(packet); |
| |
| client->callbacks.read_ready(client, buffer, client->context); |
| buffer_free(buffer); |
| } |
| |
| static void write_completed_cb(UNUSED_ATTR uint16_t local_channel_id, UNUSED_ATTR uint16_t packets_completed) { |
| // Do nothing. We update congestion state based on the congestion callback |
| // and we've already removed items from outbound_fragments list so we don't |
| // really care how many packets were successfully dispatched. |
| } |
| |
| static void fragment_packet(l2cap_client_t *client, buffer_t *packet) { |
| assert(client != NULL); |
| assert(packet != NULL); |
| |
| // TODO(sharvil): eliminate copy into BT_HDR. |
| BT_HDR *bt_packet = GKI_getbuf(buffer_length(packet) + L2CAP_MIN_OFFSET); |
| bt_packet->offset = L2CAP_MIN_OFFSET; |
| bt_packet->len = buffer_length(packet); |
| memcpy(bt_packet->data + bt_packet->offset, buffer_ptr(packet), buffer_length(packet)); |
| |
| for (;;) { |
| if (bt_packet->len <= client->remote_mtu) { |
| if (bt_packet->len > 0) |
| list_append(client->outbound_fragments, bt_packet); |
| else |
| GKI_freebuf(bt_packet); |
| break; |
| } |
| |
| BT_HDR *fragment = GKI_getbuf(client->remote_mtu + L2CAP_MIN_OFFSET); |
| fragment->offset = L2CAP_MIN_OFFSET; |
| fragment->len = client->remote_mtu; |
| memcpy(fragment->data + fragment->offset, bt_packet->data + bt_packet->offset, client->remote_mtu); |
| |
| list_append(client->outbound_fragments, fragment); |
| |
| bt_packet->offset += client->remote_mtu; |
| bt_packet->len -= client->remote_mtu; |
| } |
| } |
| |
| static void dispatch_fragments(l2cap_client_t *client) { |
| assert(client != NULL); |
| assert(!client->is_congested); |
| |
| while (!list_is_empty(client->outbound_fragments)) { |
| BT_HDR *packet = (BT_HDR *)list_front(client->outbound_fragments); |
| list_remove(client->outbound_fragments, packet); |
| |
| switch (L2CA_DataWrite(client->local_channel_id, packet)) { |
| case L2CAP_DW_CONGESTED: |
| client->is_congested = true; |
| return; |
| |
| case L2CAP_DW_FAILED: |
| LOG_ERROR(LOG_TAG, "%s error writing data to L2CAP connection LCID 0x%04x; disconnecting.", __func__, client->local_channel_id); |
| l2cap_client_disconnect(client); |
| return; |
| |
| case L2CAP_DW_SUCCESS: |
| break; |
| } |
| } |
| } |
| |
| static l2cap_client_t *find(uint16_t local_channel_id) { |
| assert(local_channel_id != 0); |
| |
| for (const list_node_t *node = list_begin(l2cap_clients); node != list_end(l2cap_clients); node = list_next(node)) { |
| l2cap_client_t *client = (l2cap_client_t *)list_node(node); |
| if (client->local_channel_id == local_channel_id) |
| return client; |
| } |
| |
| return NULL; |
| } |