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-rw-r--r--include/net/bluetooth/l2cap.h1
-rw-r--r--net/bluetooth/l2cap_core.c144
2 files changed, 87 insertions, 58 deletions
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 084dec001bf2..1c7d1cd5e679 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -44,6 +44,7 @@
#define L2CAP_DEFAULT_MAX_SDU_SIZE 0xFFFF
#define L2CAP_DEFAULT_SDU_ITIME 0xFFFFFFFF
#define L2CAP_DEFAULT_ACC_LAT 0xFFFFFFFF
+#define L2CAP_BREDR_MAX_PAYLOAD 1019 /* 3-DH5 packet */
#define L2CAP_DISC_TIMEOUT msecs_to_jiffies(100)
#define L2CAP_DISC_REJ_TIMEOUT msecs_to_jiffies(5000)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index fcd09fb4b94c..2b30bd767779 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1634,6 +1634,7 @@ static void l2cap_streaming_send(struct l2cap_chan *chan)
while ((skb = skb_dequeue(&chan->tx_q))) {
control = __get_control(chan, skb->data + L2CAP_HDR_SIZE);
control |= __set_txseq(chan, chan->next_tx_seq);
+ control |= __set_ctrl_sar(chan, bt_cb(skb)->control.sar);
__put_control(chan, control, skb->data + L2CAP_HDR_SIZE);
if (chan->fcs == L2CAP_FCS_CRC16) {
@@ -1706,6 +1707,9 @@ static int l2cap_ertm_send(struct l2cap_chan *chan)
if (chan->state != BT_CONNECTED)
return -ENOTCONN;
+ if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state))
+ return 0;
+
while ((skb = chan->tx_send_head) && (!l2cap_tx_window_full(chan))) {
if (bt_cb(skb)->control.retries == chan->remote_max_tx &&
@@ -1726,6 +1730,7 @@ static int l2cap_ertm_send(struct l2cap_chan *chan)
control |= __set_reqseq(chan, chan->buffer_seq);
control |= __set_txseq(chan, chan->next_tx_seq);
+ control |= __set_ctrl_sar(chan, bt_cb(skb)->control.sar);
__put_control(chan, control, tx_skb->data + L2CAP_HDR_SIZE);
@@ -1921,7 +1926,7 @@ static struct sk_buff *l2cap_create_basic_pdu(struct l2cap_chan *chan,
static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
struct msghdr *msg, size_t len,
- u32 control, u16 sdulen)
+ u16 sdulen)
{
struct l2cap_conn *conn = chan->conn;
struct sk_buff *skb;
@@ -1956,7 +1961,7 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
lh->cid = cpu_to_le16(chan->dcid);
lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
- __put_control(chan, control, skb_put(skb, __ctrl_size(chan)));
+ __put_control(chan, 0, skb_put(skb, __ctrl_size(chan)));
if (sdulen)
put_unaligned_le16(sdulen, skb_put(skb, L2CAP_SDULEN_SIZE));
@@ -1974,57 +1979,78 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
return skb;
}
-static int l2cap_sar_segment_sdu(struct l2cap_chan *chan, struct msghdr *msg, size_t len)
+static int l2cap_segment_sdu(struct l2cap_chan *chan,
+ struct sk_buff_head *seg_queue,
+ struct msghdr *msg, size_t len)
{
struct sk_buff *skb;
- struct sk_buff_head sar_queue;
- u32 control;
- size_t size = 0;
+ u16 sdu_len;
+ size_t pdu_len;
+ int err = 0;
+ u8 sar;
- skb_queue_head_init(&sar_queue);
- 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);
+ BT_DBG("chan %p, msg %p, len %d", chan, msg, (int)len);
- __skb_queue_tail(&sar_queue, skb);
- len -= chan->remote_mps;
- size += chan->remote_mps;
+ /* It is critical that ERTM PDUs fit in a single HCI fragment,
+ * so fragmented skbs are not used. The HCI layer's handling
+ * of fragmented skbs is not compatible with ERTM's queueing.
+ */
- while (len > 0) {
- size_t buflen;
+ /* PDU size is derived from the HCI MTU */
+ pdu_len = chan->conn->mtu;
- if (len > chan->remote_mps) {
- control = __set_ctrl_sar(chan, L2CAP_SAR_CONTINUE);
- buflen = chan->remote_mps;
- } else {
- control = __set_ctrl_sar(chan, L2CAP_SAR_END);
- buflen = len;
- }
+ pdu_len = min_t(size_t, pdu_len, L2CAP_BREDR_MAX_PAYLOAD);
+
+ /* Adjust for largest possible L2CAP overhead. */
+ pdu_len -= L2CAP_EXT_HDR_SIZE + L2CAP_FCS_SIZE;
+
+ /* Remote device may have requested smaller PDUs */
+ pdu_len = min_t(size_t, pdu_len, chan->remote_mps);
+
+ if (len <= pdu_len) {
+ sar = L2CAP_SAR_UNSEGMENTED;
+ sdu_len = 0;
+ pdu_len = len;
+ } else {
+ sar = L2CAP_SAR_START;
+ sdu_len = len;
+ pdu_len -= L2CAP_SDULEN_SIZE;
+ }
+
+ while (len > 0) {
+ skb = l2cap_create_iframe_pdu(chan, msg, pdu_len, sdu_len);
- skb = l2cap_create_iframe_pdu(chan, msg, buflen, control, 0);
if (IS_ERR(skb)) {
- skb_queue_purge(&sar_queue);
+ __skb_queue_purge(seg_queue);
return PTR_ERR(skb);
}
- __skb_queue_tail(&sar_queue, skb);
- len -= buflen;
- size += buflen;
+ bt_cb(skb)->control.sar = sar;
+ __skb_queue_tail(seg_queue, skb);
+
+ len -= pdu_len;
+ if (sdu_len) {
+ sdu_len = 0;
+ pdu_len += L2CAP_SDULEN_SIZE;
+ }
+
+ if (len <= pdu_len) {
+ sar = L2CAP_SAR_END;
+ pdu_len = len;
+ } else {
+ sar = L2CAP_SAR_CONTINUE;
+ }
}
- skb_queue_splice_tail(&sar_queue, &chan->tx_q);
- if (chan->tx_send_head == NULL)
- chan->tx_send_head = sar_queue.next;
- return size;
+ return err;
}
int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
u32 priority)
{
struct sk_buff *skb;
- u32 control;
int err;
+ struct sk_buff_head seg_queue;
/* Connectionless channel */
if (chan->chan_type == L2CAP_CHAN_CONN_LESS) {
@@ -2053,42 +2079,44 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
case L2CAP_MODE_ERTM:
case L2CAP_MODE_STREAMING:
- /* Entire SDU fits into one PDU */
- if (len <= chan->remote_mps) {
- control = __set_ctrl_sar(chan, L2CAP_SAR_UNSEGMENTED);
- skb = l2cap_create_iframe_pdu(chan, msg, len, control,
- 0);
- if (IS_ERR(skb))
- return PTR_ERR(skb);
+ /* Check outgoing MTU */
+ if (len > chan->omtu) {
+ err = -EMSGSIZE;
+ break;
+ }
- __skb_queue_tail(&chan->tx_q, skb);
+ __skb_queue_head_init(&seg_queue);
- if (chan->tx_send_head == NULL)
- chan->tx_send_head = skb;
+ /* Do segmentation before calling in to the state machine,
+ * since it's possible to block while waiting for memory
+ * allocation.
+ */
+ err = l2cap_segment_sdu(chan, &seg_queue, msg, len);
- } else {
- /* Segment SDU into multiples PDUs */
- err = l2cap_sar_segment_sdu(chan, msg, len);
- if (err < 0)
- return err;
+ /* The channel could have been closed while segmenting,
+ * check that it is still connected.
+ */
+ if (chan->state != BT_CONNECTED) {
+ __skb_queue_purge(&seg_queue);
+ err = -ENOTCONN;
}
- if (chan->mode == L2CAP_MODE_STREAMING) {
- l2cap_streaming_send(chan);
- err = len;
+ if (err)
break;
- }
- if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state) &&
- test_bit(CONN_WAIT_F, &chan->conn_state)) {
- err = len;
- break;
- }
+ skb_queue_splice_tail_init(&seg_queue, &chan->tx_q);
+ if (chan->mode == L2CAP_MODE_ERTM)
+ err = l2cap_ertm_send(chan);
+ else
+ l2cap_streaming_send(chan);
- err = l2cap_ertm_send(chan);
if (err >= 0)
err = len;
+ /* If the skbs were not queued for sending, they'll still be in
+ * seg_queue and need to be purged.
+ */
+ __skb_queue_purge(&seg_queue);
break;
default:
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.