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Bluetooth: EWS: rewrite handling SAR bits
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Segmentation and Reassembly (SAR) occupies different windows in standard and
extended control fields. Convert hardcoded masks to relative ones and use shift
to access SAR bits.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
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Andrei Emeltchenko authored and Gustavo F. Padovan committed Oct 13, 2011
1 parent ab784b7 commit 7e0ef6e
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Showing 2 changed files with 47 additions and 20 deletions.
37 changes: 32 additions & 5 deletions include/net/bluetooth/l2cap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,10 +146,10 @@ struct l2cap_conninfo {
#define L2CAP_SUPER_SREJ 0x03

/* L2CAP Segmentation and Reassembly */
#define L2CAP_SDU_UNSEGMENTED 0x0000
#define L2CAP_SDU_START 0x4000
#define L2CAP_SDU_END 0x8000
#define L2CAP_SDU_CONTINUE 0xC000
#define L2CAP_SAR_UNSEGMENTED 0x00
#define L2CAP_SAR_START 0x01
#define L2CAP_SAR_END 0x02
#define L2CAP_SAR_CONTINUE 0x03

/* L2CAP Command rej. reasons */
#define L2CAP_REJ_NOT_UNDERSTOOD 0x0000
Expand Down Expand Up @@ -516,7 +516,34 @@ static inline int l2cap_tx_window_full(struct l2cap_chan *ch)
#define __get_reqseq(ctrl) (((ctrl) & L2CAP_CTRL_REQSEQ) >> 8)
#define __is_iframe(ctrl) (!((ctrl) & L2CAP_CTRL_FRAME_TYPE))
#define __is_sframe(ctrl) ((ctrl) & L2CAP_CTRL_FRAME_TYPE)
#define __is_sar_start(ctrl) (((ctrl) & L2CAP_CTRL_SAR) == L2CAP_SDU_START)
static inline __u8 __get_ctrl_sar(struct l2cap_chan *chan, __u32 ctrl)
{
if (test_bit(FLAG_EXT_CTRL, &chan->flags))
return (ctrl & L2CAP_EXT_CTRL_SAR) >> L2CAP_EXT_CTRL_SAR_SHIFT;
else
return (ctrl & L2CAP_CTRL_SAR) >> L2CAP_CTRL_SAR_SHIFT;
}

static inline __u32 __set_ctrl_sar(struct l2cap_chan *chan, __u32 sar)
{
if (test_bit(FLAG_EXT_CTRL, &chan->flags))
return (sar << L2CAP_EXT_CTRL_SAR_SHIFT) & L2CAP_EXT_CTRL_SAR;
else
return (sar << L2CAP_CTRL_SAR_SHIFT) & L2CAP_CTRL_SAR;
}

static inline bool __is_sar_start(struct l2cap_chan *chan, __u32 ctrl)
{
return __get_ctrl_sar(chan, ctrl) == L2CAP_SAR_START;
}

static inline __u32 __get_sar_mask(struct l2cap_chan *chan)
{
if (test_bit(FLAG_EXT_CTRL, &chan->flags))
return L2CAP_EXT_CTRL_SAR;
else
return L2CAP_CTRL_SAR;
}

static inline __u8 __get_ctrl_super(struct l2cap_chan *chan, __u32 ctrl)
{
Expand Down
30 changes: 15 additions & 15 deletions net/bluetooth/l2cap_core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1311,7 +1311,7 @@ static void l2cap_retransmit_one_frame(struct l2cap_chan *chan, u8 tx_seq)
tx_skb = skb_clone(skb, GFP_ATOMIC);
bt_cb(skb)->retries++;
control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
control &= L2CAP_CTRL_SAR;
control &= __get_sar_mask(chan);

if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
control |= L2CAP_CTRL_FINAL;
Expand Down Expand Up @@ -1351,7 +1351,7 @@ static int l2cap_ertm_send(struct l2cap_chan *chan)
bt_cb(skb)->retries++;

control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
control &= L2CAP_CTRL_SAR;
control &= __get_sar_mask(chan);

if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
control |= L2CAP_CTRL_FINAL;
Expand Down Expand Up @@ -1582,7 +1582,7 @@ static int l2cap_sar_segment_sdu(struct l2cap_chan *chan, struct msghdr *msg, si
size_t size = 0;

skb_queue_head_init(&sar_queue);
control = L2CAP_SDU_START;
control = __set_ctrl_sar(chan, L2CAP_SAR_START);
skb = l2cap_create_iframe_pdu(chan, msg, chan->remote_mps, control, len);
if (IS_ERR(skb))
return PTR_ERR(skb);
Expand All @@ -1595,10 +1595,10 @@ static int l2cap_sar_segment_sdu(struct l2cap_chan *chan, struct msghdr *msg, si
size_t buflen;

if (len > chan->remote_mps) {
control = L2CAP_SDU_CONTINUE;
control = __set_ctrl_sar(chan, L2CAP_SAR_CONTINUE);
buflen = chan->remote_mps;
} else {
control = L2CAP_SDU_END;
control = __set_ctrl_sar(chan, L2CAP_SAR_END);
buflen = len;
}

Expand Down Expand Up @@ -1654,7 +1654,7 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len)
case L2CAP_MODE_STREAMING:
/* Entire SDU fits into one PDU */
if (len <= chan->remote_mps) {
control = L2CAP_SDU_UNSEGMENTED;
control = __set_ctrl_sar(chan, L2CAP_SAR_UNSEGMENTED);
skb = l2cap_create_iframe_pdu(chan, msg, len, control,
0);
if (IS_ERR(skb))
Expand Down Expand Up @@ -3201,15 +3201,15 @@ static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u1
{
int err = -EINVAL;

switch (control & L2CAP_CTRL_SAR) {
case L2CAP_SDU_UNSEGMENTED:
switch (__get_ctrl_sar(chan, control)) {
case L2CAP_SAR_UNSEGMENTED:
if (chan->sdu)
break;

err = chan->ops->recv(chan->data, skb);
break;

case L2CAP_SDU_START:
case L2CAP_SAR_START:
if (chan->sdu)
break;

Expand All @@ -3231,7 +3231,7 @@ static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u1
err = 0;
break;

case L2CAP_SDU_CONTINUE:
case L2CAP_SAR_CONTINUE:
if (!chan->sdu)
break;

Expand All @@ -3245,7 +3245,7 @@ static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u1
err = 0;
break;

case L2CAP_SDU_END:
case L2CAP_SAR_END:
if (!chan->sdu)
break;

Expand Down Expand Up @@ -3343,7 +3343,7 @@ static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
break;

skb = skb_dequeue(&chan->srej_q);
control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
control = __set_ctrl_sar(chan, bt_cb(skb)->sar);
err = l2cap_reassemble_sdu(chan, skb, control);

if (err < 0) {
Expand Down Expand Up @@ -3398,7 +3398,7 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u16 rx_cont
{
u8 tx_seq = __get_txseq(rx_control);
u8 req_seq = __get_reqseq(rx_control);
u8 sar = rx_control >> L2CAP_CTRL_SAR_SHIFT;
u8 sar = __get_ctrl_sar(chan, rx_control);
int tx_seq_offset, expected_tx_seq_offset;
int num_to_ack = (chan->tx_win/6) + 1;
int err = 0;
Expand Down Expand Up @@ -3707,7 +3707,7 @@ static int l2cap_ertm_data_rcv(struct sock *sk, struct sk_buff *skb)
if (l2cap_check_fcs(chan, skb))
goto drop;

if (__is_sar_start(control) && __is_iframe(control))
if (__is_sar_start(chan, control) && __is_iframe(control))
len -= 2;

if (chan->fcs == L2CAP_FCS_CRC16)
Expand Down Expand Up @@ -3811,7 +3811,7 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
if (l2cap_check_fcs(chan, skb))
goto drop;

if (__is_sar_start(control))
if (__is_sar_start(chan, control))
len -= 2;

if (chan->fcs == L2CAP_FCS_CRC16)
Expand Down

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