To receive l2cap connection-less data, an application has to register its service routine at the protocol/service multiplexor, together with a "PSM" - a unique number identifying the service. Connection-less data can then be sent to a specific service by sending it to the corresponding "PSM". Refer to l2cap_cl_send and bt_psm.h for further details.
#include <sys/types.h>
#include <bt/bt_defs.h>
#include <bt/bt_hci_defs.h>
#include <bt/bt_acl_pkt_buf.h>
#include <bt/bt_psm.h>
Defines | |
| #define | L2CAP_CL_PSM_FIELD_SIZE 2 |
| Size of the PSM field. | |
Errors | |
| #define | L2CAP_CL_ERR_PAYLOAD_OVERFLOW -1 |
Functions | |
| u_long | l2cap_cl_get_arrival_time (bt_acl_pkt_buf *pkt_buf) |
| Returns the arrival time of the packet passed. | |
| u_char * | l2cap_cl_get_data_ptr (struct bt_hci_pkt_acl *pkt) |
| Returns indexed drop counter. Increments indexed drop counter. Increments also the above drop counter. Returns a pointer to the payload of a received l2cap connection-less packet. | |
| u_short | l2cap_cl_max_payload (void) |
| Returns the max payload size of a connection-less l2cap packet. | |
Sending L2CAP connection-less Data | |
| long | l2cap_cl_acquire_write_lock (bt_hci_con_handle_t hdl, u_short psm, u_short len) |
| Acquires lock on bt-uart for sending l2cap connection-less data. | |
| long | l2cap_cl_lowlevel_write (u_char *data, u_short len) |
| Writes connection-less data to the bluetooth uart. | |
| void | l2cap_cl_release_write_lock (void) |
| Releases unique access for sending l2cap connection-less data. | |
| long | l2cap_cl_send (u_char *data, u_short len, bt_hci_con_handle_t hdl, u_short psm) |
| Sends a connection-less l2cap data packet. | |
Packet statistics | |
| u_long | l2cap_cl_get_dropped_traffic (void) |
| Returns the number of dropped packets. | |
| u_long | l2cap_cl_get_incoming_traffic (void) |
| Returns the number of received packets. | |
| u_long | l2cap_cl_get_outgoing_traffic (void) |
| Returns the number of sent packets. | |
| void | l2cap_cl_increment_drop_counter (void) |
| Increments drop counter. | |
Initialization | |
| void | l2cap_cl_init (struct btstack *bt_stack, bt_psm_t *mux) |
| Initializes the connectionless l2cap layer. | |
L2CAP callback registration | |
| void | l2cap_cl_register_acl_cb (struct btstack *bt_stack, HCI_ACL_CB, void *arg) |
| To register a callback funtion handling L2CAP data packets. | |
| #define L2CAP_CL_ERR_PAYLOAD_OVERFLOW -1 |
The payload of the l2cap connection-less data packet to send is too large
| long l2cap_cl_acquire_write_lock | ( | bt_hci_con_handle_t | hdl, | |
| u_short | psm, | |||
| u_short | len | |||
| ) |
Acquires lock on bt-uart for sending l2cap connection-less data.
Locks the bluetooth uart for writing l2cap connection-less data. The lock is not released until l2cap_cl_release_write_lock has been called.
Note: Applications typically do not call this function, but make use of l2cap_cl_send instead.
| hdl | Connection handle of the connected neighbor device the data shall be sent to. | |
| psm | PSM the data will be sent to on the receiving side. | |
| len | Amount of data to be sent. |
| u_char* l2cap_cl_get_data_ptr | ( | struct bt_hci_pkt_acl * | pkt | ) | [inline] |
Returns indexed drop counter. Increments indexed drop counter. Increments also the above drop counter. Returns a pointer to the payload of a received l2cap connection-less packet.
| pkt | Pointer to the received packet |
Initializes the connectionless l2cap layer.
Note: The bt-stack, the ACL layer, as well as the protocol/service multiplexor have to be initialized before calling this function. Thus, make shure that:
| bt_stack | Pointer to the bt-stack to use | |
| mux | Pointer to the protocol/service multiplexor to use |
Writes connection-less data to the bluetooth uart.
Writes l2cap connection-less data directely to the bt uart iff unique write access has been aquired before (i.e. l2cap_cl_acquire_write_lock has been called).
Note: Applications typically do not call this function, but make use of l2cap_cl_send instead.
| data | Data to write | |
| len | Size of the data to write |
| void l2cap_cl_register_acl_cb | ( | struct btstack * | bt_stack, | |
| HCI_ACL_CB | , | |||
| void * | arg | |||
| ) |
To register a callback funtion handling L2CAP data packets.
Call this function to register a higher layer service (i.e. l2cap) which handles the data that is not handled by the l2cap connection-less layer (i.e. l2cap packets that are not sent to the connection-less channel).
Note: l2cap_cl and l2cap cannot run together at the moment!
| void l2cap_cl_release_write_lock | ( | void | ) | [inline] |
Releases unique access for sending l2cap connection-less data.
Releases the writing lock on the bluetooth controller triggered by l2cap_cl_acquire_write_lock.
Note: Applications typically do not call this function, but make use of l2cap_cl_send instead.
| long l2cap_cl_send | ( | u_char * | data, | |
| u_short | len, | |||
| bt_hci_con_handle_t | hdl, | |||
| u_short | psm | |||
| ) |
Sends a connection-less l2cap data packet.
Sends connection-less l2cap data of length len over connection handle con_handle to the psm psm.
Note: The maximal amount of data that can be sent is obtained by calling l2cap_cl_max_payload.
| data | pointer to the data to be sent | |
| len | amount of data to be sent | |
| hdl | connection handle the data shall be sent to | |
| psm | PSM the data shall be sent to (the PSM identifies the service the data will be delivered to on the receiving side (see bt_psm_service_register). |
u_char data[12]; strcpy(data, "hello world"); l2cap_cl_send(data, <con_handle>, <psm>, 12);
1.5.1