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Bluetooth: Use non-flushable by default L2CAP data packets

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Modification of Nick Pelly <npelly@google.com> patch.

With Bluetooth 2.1 ACL packets can be flushable or non-flushable. This commit
makes ACL data packets non-flushable by default on compatible chipsets, and
adds the BT_FLUSHABLE socket option to explicitly request flushable ACL
data packets for a given L2CAP socket. This is useful for A2DP data which can
be safely discarded if it can not be delivered within a short time (while
other ACL data should not be discarded).

Note that making ACL data flushable has no effect unless the automatic flush
timeout for that ACL link is changed from its default of 0 (infinite).

Default packet types (for compatible chipsets):
Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
Bluetooth HCI H4
Bluetooth HCI ACL Packet
    .... 0000 0000 0010 = Connection Handle: 0x0002
    ..00 .... .... .... = PB Flag: First Non-automatically Flushable Packet (0)
    00.. .... .... .... = BC Flag: Point-To-Point (0)
    Data Total Length: 8
Bluetooth L2CAP Packet

After setting BT_FLUSHABLE
(sock.setsockopt(274 /*SOL_BLUETOOTH*/, 8 /* BT_FLUSHABLE */, 1 /* flush */))
Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
Bluetooth HCI H4
Bluetooth HCI ACL Packet
    .... 0000 0000 0010 = Connection Handle: 0x0002
    ..10 .... .... .... = PB Flag: First Automatically Flushable Packet (2)
    00.. .... .... .... = BC Flag: Point-To-Point (0)
    Data Total Length: 8
Bluetooth L2CAP Packet

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This commit is contained in:
Andrei Emeltchenko
2011-01-03 11:14:36 +02:00
committed by Gustavo F. Padovan
parent b2c60d42db
commit e702112ff6
6 changed files with 69 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
include/net/bluetooth/bluetooth.h
View File

@@ -64,6 +64,11 @@ struct bt_security {
#define BT_DEFER_SETUP 7
#define BT_FLUSHABLE 8
#define BT_FLUSHABLE_OFF 0
#define BT_FLUSHABLE_ON 1
#define BT_INFO(fmt, arg...) printk(KERN_INFO "Bluetooth: " fmt "\n" , ## arg)
#define BT_ERR(fmt, arg...) printk(KERN_ERR "%s: " fmt "\n" , __func__ , ## arg)
#define BT_DBG(fmt, arg...) pr_debug("%s: " fmt "\n" , __func__ , ## arg)

2
include/net/bluetooth/hci.h
View File

@@ -150,6 +150,7 @@ enum {
#define EDR_ESCO_MASK (ESCO_2EV3 | ESCO_3EV3 | ESCO_2EV5 | ESCO_3EV5)
/* ACL flags */
#define ACL_START_NO_FLUSH 0x00
#define ACL_CONT 0x01
#define ACL_START 0x02
#define ACL_ACTIVE_BCAST 0x04
@@ -194,6 +195,7 @@ enum {
#define LMP_EDR_3S_ESCO 0x80
#define LMP_SIMPLE_PAIR 0x08
#define LMP_NO_FLUSH 0x40
/* Connection modes */
#define HCI_CM_ACTIVE 0x0000

1
include/net/bluetooth/hci_core.h
View File

@@ -458,6 +458,7 @@ void hci_conn_del_sysfs(struct hci_conn *conn);
#define lmp_sniffsubr_capable(dev) ((dev)->features[5] & LMP_SNIFF_SUBR)
#define lmp_esco_capable(dev) ((dev)->features[3] & LMP_ESCO)
#define lmp_ssp_capable(dev) ((dev)->features[6] & LMP_SIMPLE_PAIR)
#define lmp_no_flush_capable(dev) ((dev)->features[6] & LMP_NO_FLUSH)
/* ----- HCI protocols ----- */
struct hci_proto {

1
include/net/bluetooth/l2cap.h
View File

@@ -327,6 +327,7 @@ struct l2cap_pinfo {
__u8 sec_level;
__u8 role_switch;
__u8 force_reliable;
__u8 flushable;
__u8 conf_req[64];
__u8 conf_len;