Use sk_buff fragment capabilities to link together incoming skbs
instead of allocating a new skb for reassembly and copying.
The new reassembly code works equally well for ERTM and streaming
mode, so there is now one reassembly function instead of two.
Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
---
include/net/bluetooth/l2cap.h | 3 +-
net/bluetooth/l2cap_core.c | 243 ++++++++++++++---------------------------
2 files changed, 81 insertions(+), 165 deletions(-)
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 4f34ad2..6fa1140 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -354,8 +354,8 @@ struct l2cap_chan {
__u8 retry_count;
__u8 num_acked;
__u16 sdu_len;
- __u16 partial_sdu_len;
struct sk_buff *sdu;
+ struct sk_buff *sdu_last_frag;
__u8 remote_tx_win;
__u8 remote_max_tx;
@@ -454,7 +454,6 @@ enum {
#define L2CAP_CONF_MAX_CONF_RSP 2
enum {
- CONN_SAR_SDU,
CONN_SREJ_SENT,
CONN_WAIT_F,
CONN_SREJ_ACT,
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index f7f8e2c..0045b1e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3121,102 +3121,104 @@ static int l2cap_add_to_srej_queue(struct l2cap_chan *chan, struct sk_buff *skb,
return 0;
}
-static int l2cap_ertm_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
+static void append_skb_frag(struct sk_buff *skb,
+ struct sk_buff *new_frag, struct sk_buff **last_frag)
{
- struct sk_buff *_skb;
- int err;
+ /* skb->len reflects data in skb as well as all fragments
+ * skb->data_len reflects only data in fragments
+ */
+ if (!skb_has_frag_list(skb))
+ skb_shinfo(skb)->frag_list = new_frag;
+
+ new_frag->next = NULL;
+
+ (*last_frag)->next = new_frag;
+ *last_frag = new_frag;
+
+ skb->len += new_frag->len;
+ skb->data_len += new_frag->len;
+ skb->truesize += new_frag->truesize;
+}
+
+static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
+{
+ int err = -EINVAL;
switch (control & L2CAP_CTRL_SAR) {
case L2CAP_SDU_UNSEGMENTED:
- if (test_bit(CONN_SAR_SDU, &chan->conn_state))
- goto drop;
+ if (chan->sdu)
+ break;
- return chan->ops->recv(chan->data, skb);
+ err = chan->ops->recv(chan->data, skb);
+ break;
case L2CAP_SDU_START:
- if (test_bit(CONN_SAR_SDU, &chan->conn_state))
- goto drop;
+ if (chan->sdu)
+ break;
chan->sdu_len = get_unaligned_le16(skb->data);
+ skb_pull(skb, 2);
- if (chan->sdu_len > chan->imtu)
- goto disconnect;
-
- chan->sdu = bt_skb_alloc(chan->sdu_len, GFP_ATOMIC);
- if (!chan->sdu)
- return -ENOMEM;
+ if (chan->sdu_len > chan->imtu) {
+ err = -EMSGSIZE;
+ break;
+ }
- /* pull sdu_len bytes only after alloc, because of Local Busy
- * condition we have to be sure that this will be executed
- * only once, i.e., when alloc does not fail */
- skb_pull(skb, 2);
+ if (skb->len >= chan->sdu_len)
+ break;
- memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
+ chan->sdu = skb;
+ chan->sdu_last_frag = skb;
- set_bit(CONN_SAR_SDU, &chan->conn_state);
- chan->partial_sdu_len = skb->len;
+ skb = NULL;
+ err = 0;
break;
case L2CAP_SDU_CONTINUE:
- if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
- goto disconnect;
-
if (!chan->sdu)
- goto disconnect;
+ break;
- chan->partial_sdu_len += skb->len;
- if (chan->partial_sdu_len > chan->sdu_len)
- goto drop;
+ append_skb_frag(chan->sdu, skb,
+ &chan->sdu_last_frag);
+ skb = NULL;
- memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
+ if (chan->sdu->len >= chan->sdu_len)
+ break;
+ err = 0;
break;
case L2CAP_SDU_END:
- if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
- goto disconnect;
-
if (!chan->sdu)
- goto disconnect;
-
- chan->partial_sdu_len += skb->len;
-
- if (chan->partial_sdu_len > chan->imtu)
- goto drop;
+ break;
- if (chan->partial_sdu_len != chan->sdu_len)
- goto drop;
+ append_skb_frag(chan->sdu, skb,
+ &chan->sdu_last_frag);
+ skb = NULL;
- memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
+ if (chan->sdu->len != chan->sdu_len)
+ break;
- _skb = skb_clone(chan->sdu, GFP_ATOMIC);
- if (!_skb) {
- return -ENOMEM;
- }
+ err = chan->ops->recv(chan->data, chan->sdu);
- err = chan->ops->recv(chan->data, _skb);
- if (err < 0) {
- kfree_skb(_skb);
- return err;
+ if (!err) {
+ /* Reassembly complete */
+ chan->sdu = NULL;
+ chan->sdu_last_frag = NULL;
+ chan->sdu_len = 0;
}
-
- clear_bit(CONN_SAR_SDU, &chan->conn_state);
-
- kfree_skb(chan->sdu);
break;
}
- kfree_skb(skb);
- return 0;
-
-drop:
- kfree_skb(chan->sdu);
- chan->sdu = NULL;
+ if (err) {
+ kfree_skb(skb);
+ kfree_skb(chan->sdu);
+ chan->sdu = NULL;
+ chan->sdu_last_frag = NULL;
+ chan->sdu_len = 0;
+ }
-disconnect:
- l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
- kfree_skb(skb);
- return 0;
+ return err;
}
static void l2cap_ertm_enter_local_busy(struct l2cap_chan *chan)
@@ -3270,99 +3272,6 @@ void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
}
}
-static int l2cap_streaming_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
-{
- struct sk_buff *_skb;
- int err = -EINVAL;
-
- /*
- * TODO: We have to notify the userland if some data is lost with the
- * Streaming Mode.
- */
-
- switch (control & L2CAP_CTRL_SAR) {
- case L2CAP_SDU_UNSEGMENTED:
- if (test_bit(CONN_SAR_SDU, &chan->conn_state)) {
- kfree_skb(chan->sdu);
- break;
- }
-
- err = chan->ops->recv(chan->data, skb);
- if (!err)
- return 0;
-
- break;
-
- case L2CAP_SDU_START:
- if (test_bit(CONN_SAR_SDU, &chan->conn_state)) {
- kfree_skb(chan->sdu);
- break;
- }
-
- chan->sdu_len = get_unaligned_le16(skb->data);
- skb_pull(skb, 2);
-
- if (chan->sdu_len > chan->imtu) {
- err = -EMSGSIZE;
- break;
- }
-
- chan->sdu = bt_skb_alloc(chan->sdu_len, GFP_ATOMIC);
- if (!chan->sdu) {
- err = -ENOMEM;
- break;
- }
-
- memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
-
- set_bit(CONN_SAR_SDU, &chan->conn_state);
- chan->partial_sdu_len = skb->len;
- err = 0;
- break;
-
- case L2CAP_SDU_CONTINUE:
- if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
- break;
-
- memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
-
- chan->partial_sdu_len += skb->len;
- if (chan->partial_sdu_len > chan->sdu_len)
- kfree_skb(chan->sdu);
- else
- err = 0;
-
- break;
-
- case L2CAP_SDU_END:
- if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
- break;
-
- memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
-
- clear_bit(CONN_SAR_SDU, &chan->conn_state);
- chan->partial_sdu_len += skb->len;
-
- if (chan->partial_sdu_len > chan->imtu)
- goto drop;
-
- if (chan->partial_sdu_len == chan->sdu_len) {
- _skb = skb_clone(chan->sdu, GFP_ATOMIC);
- err = chan->ops->recv(chan->data, _skb);
- if (err < 0)
- kfree_skb(_skb);
- }
- err = 0;
-
-drop:
- kfree_skb(chan->sdu);
- break;
- }
-
- kfree_skb(skb);
- return err;
-}
-
static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
{
struct sk_buff *skb;
@@ -3377,7 +3286,7 @@ static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
skb = skb_dequeue(&chan->srej_q);
control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
- err = l2cap_ertm_reassembly_sdu(chan, skb, control);
+ err = l2cap_reassemble_sdu(chan, skb, control);
if (err < 0) {
l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
@@ -3537,7 +3446,7 @@ expected:
return 0;
}
- err = l2cap_ertm_reassembly_sdu(chan, skb, rx_control);
+ err = l2cap_reassemble_sdu(chan, skb, rx_control);
chan->buffer_seq = (chan->buffer_seq + 1) % 64;
if (err < 0) {
l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
@@ -3853,12 +3762,20 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
tx_seq = __get_txseq(control);
- if (chan->expected_tx_seq == tx_seq)
- chan->expected_tx_seq = (chan->expected_tx_seq + 1) % 64;
- else
- chan->expected_tx_seq = (tx_seq + 1) % 64;
+ if (chan->expected_tx_seq != tx_seq) {
+ /* Frame(s) missing - must discard partial SDU */
+ kfree_skb(chan->sdu);
+ chan->sdu = NULL;
+ chan->sdu_last_frag = NULL;
+ chan->sdu_len = 0;
- l2cap_streaming_reassembly_sdu(chan, skb, control);
+ /* TODO: Notify userland of missing data */
+ }
+
+ chan->expected_tx_seq = (tx_seq + 1) % 64;
+
+ if (l2cap_reassemble_sdu(chan, skb, control) == -EMSGSIZE)
+ l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
goto done;
--
1.7.6
--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
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