ERTM should use Segmentation and Reassembly to break down a SDU in many
PDUs on sending data to the other side.
On sending packets we queue all 'segments' until end of segmentation and
just the add them to the queue for sending.
On receiving we create a new skb with the SDU reassembled.
Initially based on a patch from Nathan Holstein <[email protected]>
Signed-off-by: Gustavo F. Padovan <[email protected]>
---
include/net/bluetooth/l2cap.h | 10 ++-
net/bluetooth/l2cap.c | 169 +++++++++++++++++++++++++++++++++++++----
2 files changed, 162 insertions(+), 17 deletions(-)
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 9bbfbe7..9189328 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -34,7 +34,7 @@
#define L2CAP_DEFAULT_MAX_RECEIVE 1
#define L2CAP_DEFAULT_RETRANS_TO 300 /* 300 milliseconds */
#define L2CAP_DEFAULT_MONITOR_TO 1000 /* 1 second */
-#define L2CAP_DEFAULT_MAX_RX_APDU 0xfff7
+#define L2CAP_DEFAULT_MAX_PDU_SIZE 672
#define L2CAP_CONN_TIMEOUT (40000) /* 40 seconds */
#define L2CAP_INFO_TIMEOUT (4000) /* 4 seconds */
@@ -311,6 +311,7 @@ struct l2cap_pinfo {
__u8 conf_req[64];
__u8 conf_len;
__u8 conf_state;
+ __u8 conn_state;
__u8 next_tx_seq;
__u8 expected_ack_seq;
@@ -318,6 +319,10 @@ struct l2cap_pinfo {
__u8 expected_tx_seq;
__u8 unacked_frames;
__u8 num_to_ack;
+ __u16 sdu_len;
+ __u16 partial_sdu_len;
+ __u8 start_txseq;
+ struct sk_buff *sdu;
__u8 ident;
@@ -346,6 +351,8 @@ struct l2cap_pinfo {
#define L2CAP_CONF_MAX_CONF_REQ 2
#define L2CAP_CONF_MAX_CONF_RSP 2
+#define L2CAP_CONN_SAR_SDU 0x01
+
static inline int l2cap_tx_window_full(struct sock *sk)
{
struct l2cap_pinfo *pi = l2cap_pi(sk);
@@ -363,6 +370,7 @@ static inline int l2cap_tx_window_full(struct sock *sk)
#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
void l2cap_load(void);
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index a4e3cdc..16c448d 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1339,7 +1339,7 @@ static struct sk_buff *l2cap_create_basic_pdu(struct sock *sk, struct msghdr *ms
return skb;
}
-static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg, size_t len, u16 control)
+static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg, size_t len, u16 control, u16 sdulen)
{
struct l2cap_conn *conn = l2cap_pi(sk)->conn;
struct sk_buff *skb;
@@ -1348,6 +1348,9 @@ static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg
BT_DBG("sk %p len %d", sk, (int)len);
+ if (sdulen)
+ hlen +=2;
+
count = min_t(unsigned int, (conn->mtu - hlen), len);
skb = bt_skb_send_alloc(sk, count + hlen,
msg->msg_flags & MSG_DONTWAIT, &err);
@@ -1359,6 +1362,8 @@ static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg
lh->cid = cpu_to_le16(l2cap_pi(sk)->dcid);
lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
put_unaligned_le16(control, skb_put(skb, 2));
+ if (sdulen)
+ put_unaligned_le16(sdulen, skb_put(skb, 2));
err = l2cap_skbuff_fromiovec(sk, msg, len, count, skb);
if (unlikely(err < 0)) {
@@ -1368,6 +1373,54 @@ static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg
return skb;
}
+static inline int l2cap_sar_segment_sdu(struct sock *sk, struct msghdr *msg, size_t len)
+{
+ struct l2cap_pinfo *pi = l2cap_pi(sk);
+ struct sk_buff *skb;
+ struct sk_buff_head sar_queue;
+ u16 control;
+ size_t size = 0;
+
+ __skb_queue_head_init(&sar_queue);
+ control = L2CAP_SDU_START;
+ skb = l2cap_create_ertm_pdu(sk, msg, pi->max_pdu_size, control, len);
+ if (IS_ERR(skb))
+ return PTR_ERR(skb);
+
+ __skb_queue_tail(&sar_queue, skb);
+ len -= pi->max_pdu_size;
+ size +=pi->max_pdu_size;
+ control = 0;
+
+ while (len > 0) {
+ size_t buflen;
+
+ if (len > pi->max_pdu_size) {
+ control |= L2CAP_SDU_CONTINUE;
+ buflen = pi->max_pdu_size;
+ } else {
+ control |= L2CAP_SDU_END;
+ buflen = len;
+ }
+
+ skb = l2cap_create_ertm_pdu(sk, msg, buflen, control, 0);
+ if (IS_ERR(skb)) {
+ skb_queue_purge(&sar_queue);
+ return PTR_ERR(skb);
+ }
+
+ __skb_queue_tail(&sar_queue, skb);
+ len -= buflen;
+ size += buflen;
+ control = 0;
+ }
+ skb_queue_splice_tail(&sar_queue, TX_QUEUE(sk));
+ if (sk->sk_send_head == NULL)
+ sk->sk_send_head = sar_queue.next;
+
+ return size;
+}
+
static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
@@ -1420,22 +1473,23 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
case L2CAP_MODE_ERTM:
/* Entire SDU fits into one PDU */
- if (len <= pi->omtu) {
+ if (len <= pi->max_pdu_size) {
control = L2CAP_SDU_UNSEGMENTED;
- skb = l2cap_create_ertm_pdu(sk, msg, len, control);
+ skb = l2cap_create_ertm_pdu(sk, msg, len, control, 0);
if (IS_ERR(skb)) {
err = PTR_ERR(skb);
goto done;
}
+ __skb_queue_tail(TX_QUEUE(sk), skb);
+ if (sk->sk_send_head == NULL)
+ sk->sk_send_head = skb;
}
+ /* Segment SDU into multiples PDUs */
else {
- /* FIXME: Segmentation will be added later */
- err = -EINVAL;
- goto done;
+ err = l2cap_sar_segment_sdu(sk, msg, len);
+ if (err < 0)
+ goto done;
}
- __skb_queue_tail(TX_QUEUE(sk), skb);
- if (sk->sk_send_head == NULL)
- sk->sk_send_head = skb;
err = l2cap_ertm_send(sk);
if (!err)
@@ -2013,7 +2067,7 @@ done:
rfc.max_transmit = L2CAP_DEFAULT_MAX_RECEIVE;
rfc.retrans_timeout = 0;
rfc.monitor_timeout = 0;
- rfc.max_pdu_size = cpu_to_le16(L2CAP_DEFAULT_MAX_RX_APDU);
+ rfc.max_pdu_size = cpu_to_le16(L2CAP_DEFAULT_MAX_PDU_SIZE);
l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
sizeof(rfc), (unsigned long) &rfc);
@@ -2025,7 +2079,7 @@ done:
rfc.max_transmit = 0;
rfc.retrans_timeout = 0;
rfc.monitor_timeout = 0;
- rfc.max_pdu_size = cpu_to_le16(L2CAP_DEFAULT_MAX_RX_APDU);
+ rfc.max_pdu_size = cpu_to_le16(L2CAP_DEFAULT_MAX_PDU_SIZE);
l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
sizeof(rfc), (unsigned long) &rfc);
@@ -2814,6 +2868,85 @@ static inline void l2cap_sig_channel(struct l2cap_conn *conn, struct sk_buff *sk
kfree_skb(skb);
}
+static int l2cap_sar_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 control, u8 txseq)
+{
+ struct l2cap_pinfo *pi = l2cap_pi(sk);
+ struct sk_buff *_skb;
+ int err = -EINVAL;
+
+ switch (control & L2CAP_CTRL_SAR) {
+ case L2CAP_SDU_UNSEGMENTED:
+ if (pi->conn_state & L2CAP_CONN_SAR_SDU)
+ goto drop2;
+
+ err = sock_queue_rcv_skb(sk, skb);
+ if (err < 0)
+ goto drop;
+ break;
+
+ case L2CAP_SDU_START:
+ if (pi->conn_state & L2CAP_CONN_SAR_SDU)
+ goto drop2;
+
+ pi->sdu_len = get_unaligned_le16(skb->data);
+ skb_pull(skb, 2);
+
+ pi->sdu = bt_skb_alloc(pi->sdu_len, GFP_ATOMIC);
+ if (!pi->sdu)
+ goto drop;
+
+ memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
+
+ pi->conn_state |= L2CAP_CONN_SAR_SDU;
+ pi->partial_sdu_len = skb->len;
+ pi->start_txseq = txseq;
+ kfree_skb(skb);
+ break;
+
+ case L2CAP_SDU_CONTINUE:
+ if (!(pi->conn_state & L2CAP_CONN_SAR_SDU))
+ goto drop;
+
+ memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
+
+ pi->partial_sdu_len += skb->len;
+ if (pi->partial_sdu_len > pi->sdu_len)
+ goto drop2;
+
+ kfree_skb(skb);
+ break;
+
+ case L2CAP_SDU_END:
+ if (!(pi->conn_state & L2CAP_CONN_SAR_SDU))
+ goto drop;
+
+ memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
+
+ pi->conn_state &= ~L2CAP_CONN_SAR_SDU;
+ pi->partial_sdu_len += skb->len;
+
+ if (pi->partial_sdu_len != pi->sdu_len)
+ goto drop2;
+
+ _skb = skb_clone(pi->sdu, GFP_ATOMIC);
+ err = sock_queue_rcv_skb(sk, _skb);
+ if (err < 0)
+ kfree_skb(_skb);
+
+ kfree_skb(pi->sdu);
+ kfree_skb(skb);
+ break;
+ }
+ return 0;
+
+drop2:
+ kfree_skb(pi->sdu);
+
+drop:
+ kfree_skb(skb);
+ return err;
+}
+
static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
{
struct l2cap_pinfo *pi = l2cap_pi(sk);
@@ -2826,11 +2959,11 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
if (tx_seq != pi->expected_tx_seq)
return -EINVAL;
- pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
- err = sock_queue_rcv_skb(sk, skb);
- if (err)
+ err = l2cap_sar_reassembly_sdu(sk, skb, rx_control, tx_seq);
+ if (err < 0)
return err;
+ pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
tx_control |= L2CAP_CTRL_FRAME_TYPE;
@@ -2866,7 +2999,7 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk_buff *skb)
{
struct sock *sk;
- u16 control;
+ u16 control, len;
int err;
sk = l2cap_get_chan_by_scid(&conn->chan_list, cid);
@@ -2897,8 +3030,12 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
case L2CAP_MODE_ERTM:
control = get_unaligned_le16(skb->data);
skb_pull(skb, 2);
+ len = skb->len;
- if (l2cap_pi(sk)->imtu < skb->len)
+ if (__is_sar_start(control))
+ len -= 2;
+
+ if (len > L2CAP_DEFAULT_MAX_PDU_SIZE)
goto drop;
if (__is_iframe(control))
--
1.6.3.3
L2CAP uses rentransmission and monitor timers to inquiry the other side
about unacked I-frames. After send each I-frame we (re)start the
retransmission timer, if it expires, we start a monitor timer that send a
S-frame with P bit set and wait for S-frame with F bit set.
If monitor timer expires, it try again, at a maximum of
L2CAP_DEFAULT_MAX_TX.
Signed-off-by: Gustavo F. Padovan <[email protected]>
---
include/net/bluetooth/bluetooth.h | 1 +
include/net/bluetooth/l2cap.h | 15 +++++-
net/bluetooth/l2cap.c | 81 +++++++++++++++++++++++++++++++++++--
3 files changed, 90 insertions(+), 7 deletions(-)
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 65a5cf8..b8b9a84 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -139,6 +139,7 @@ struct bt_skb_cb {
__u8 pkt_type;
__u8 incoming;
__u8 tx_seq;
+ __u8 retries;
};
#define bt_cb(skb) ((struct bt_skb_cb *)((skb)->cb))
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index c54b72a..aeadd7d 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -31,9 +31,9 @@
#define L2CAP_DEFAULT_FLUSH_TO 0xffff
#define L2CAP_DEFAULT_TX_WINDOW 63
#define L2CAP_DEFAULT_NUM_TO_ACK (L2CAP_DEFAULT_TX_WINDOW/5)
-#define L2CAP_DEFAULT_MAX_RECEIVE 1
-#define L2CAP_DEFAULT_RETRANS_TO 300 /* 300 milliseconds */
-#define L2CAP_DEFAULT_MONITOR_TO 1000 /* 1 second */
+#define L2CAP_DEFAULT_MAX_TX 3
+#define L2CAP_DEFAULT_RETRANS_TO 1000 /* 1 second */
+#define L2CAP_DEFAULT_MONITOR_TO 12000 /* 12 seconds */
#define L2CAP_DEFAULT_MAX_PDU_SIZE 672
#define L2CAP_CONN_TIMEOUT (40000) /* 40 seconds */
@@ -318,6 +318,7 @@ struct l2cap_pinfo {
__u8 req_seq;
__u8 expected_tx_seq;
__u8 unacked_frames;
+ __u8 retry_count;
__u8 num_to_ack;
__u16 sdu_len;
__u16 partial_sdu_len;
@@ -334,6 +335,8 @@ struct l2cap_pinfo {
__le16 sport;
+ struct timer_list retrans_timer;
+ struct timer_list monitor_timer;
struct sk_buff_head tx_queue;
struct l2cap_conn *conn;
struct sock *next_c;
@@ -353,6 +356,12 @@ struct l2cap_pinfo {
#define L2CAP_CONN_SAR_SDU 0x01
#define L2CAP_CONN_UNDER_REJ 0x02
+#define L2CAP_CONN_WAIT_ACK 0x04
+
+#define __mod_retrans_timer() mod_timer(&l2cap_pi(sk)->retrans_timer, \
+ jiffies + msecs_to_jiffies(L2CAP_DEFAULT_RETRANS_TO));
+#define __mod_monitor_timer() mod_timer(&l2cap_pi(sk)->monitor_timer, \
+ jiffies + msecs_to_jiffies(L2CAP_DEFAULT_MONITOR_TO));
static inline int l2cap_tx_window_full(struct sock *sk)
{
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 918cc15..0ce89c3 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1179,6 +1179,37 @@ static int l2cap_sock_getname(struct socket *sock, struct sockaddr *addr, int *l
return 0;
}
+static void l2cap_monitor_timeout(unsigned long arg)
+{
+ struct sock *sk = (void *) arg;
+ u16 control;
+
+ if (l2cap_pi(sk)->retry_count >= l2cap_pi(sk)->remote_max_tx) {
+ l2cap_send_disconn_req(l2cap_pi(sk)->conn, sk);
+ return;
+ }
+
+ l2cap_pi(sk)->retry_count++;
+ __mod_monitor_timer();
+
+ control = L2CAP_CTRL_POLL;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+}
+
+static void l2cap_retrans_timeout(unsigned long arg)
+{
+ struct sock *sk = (void *) arg;
+ u16 control;
+
+ l2cap_pi(sk)->retry_count = 1;
+ __mod_monitor_timer();
+
+ l2cap_pi(sk)->conn_state |= L2CAP_CONN_WAIT_ACK;
+
+ control = L2CAP_CTRL_POLL;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+}
+
static void l2cap_drop_acked_frames(struct sock *sk)
{
struct sk_buff *skb;
@@ -1193,6 +1224,9 @@ static void l2cap_drop_acked_frames(struct sock *sk)
l2cap_pi(sk)->unacked_frames--;
}
+ if (!l2cap_pi(sk)->unacked_frames)
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+
return;
}
@@ -1219,10 +1253,21 @@ static int l2cap_ertm_send(struct sock *sk)
u16 *control;
int err;
+ if (pi->conn_state & L2CAP_CONN_WAIT_ACK)
+ return 0;
+
while ((skb = sk->sk_send_head) && (!l2cap_tx_window_full(sk))) {
tx_seq = pi->next_tx_seq;
tx_skb = skb_clone(skb, GFP_ATOMIC);
+ if (pi->remote_max_tx &&
+ bt_cb(skb)->retries == pi->remote_max_tx) {
+ l2cap_send_disconn_req(pi->conn, sk);
+ break;
+ }
+
+ bt_cb(skb)->retries++;
+
control = (u16 *)(skb->data + L2CAP_HDR_SIZE);
*control |= cpu_to_le16(
(pi->req_seq << L2CAP_CTRL_REQSEQ_SHIFT)
@@ -1234,6 +1279,8 @@ static int l2cap_ertm_send(struct sock *sk)
return err;
}
+ __mod_retrans_timer();
+
pi->next_tx_seq = (pi->next_tx_seq + 1) % 64;
bt_cb(skb)->tx_seq = tx_seq;
@@ -1370,6 +1417,8 @@ static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg
kfree_skb(skb);
return ERR_PTR(err);
}
+
+ bt_cb(skb)->retries = 0;
return skb;
}
@@ -2064,7 +2113,7 @@ done:
case L2CAP_MODE_ERTM:
rfc.mode = L2CAP_MODE_ERTM;
rfc.txwin_size = L2CAP_DEFAULT_TX_WINDOW;
- rfc.max_transmit = L2CAP_DEFAULT_MAX_RECEIVE;
+ rfc.max_transmit = L2CAP_DEFAULT_MAX_TX;
rfc.retrans_timeout = 0;
rfc.monitor_timeout = 0;
rfc.max_pdu_size = cpu_to_le16(L2CAP_DEFAULT_MAX_PDU_SIZE);
@@ -2559,6 +2608,12 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
l2cap_pi(sk)->next_tx_seq = 0;
l2cap_pi(sk)->expected_ack_seq = 0;
l2cap_pi(sk)->unacked_frames = 0;
+
+ setup_timer(&l2cap_pi(sk)->retrans_timer,
+ l2cap_retrans_timeout, (unsigned long) sk);
+ setup_timer(&l2cap_pi(sk)->monitor_timer,
+ l2cap_monitor_timeout, (unsigned long) sk);
+
__skb_queue_head_init(TX_QUEUE(sk));
l2cap_chan_ready(sk);
goto unlock;
@@ -2668,6 +2723,8 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
sk->sk_shutdown = SHUTDOWN_MASK;
skb_queue_purge(TX_QUEUE(sk));
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+ del_timer(&l2cap_pi(sk)->monitor_timer);
l2cap_chan_del(sk, ECONNRESET);
bh_unlock_sock(sk);
@@ -2692,6 +2749,8 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd
return 0;
skb_queue_purge(TX_QUEUE(sk));
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+ del_timer(&l2cap_pi(sk)->monitor_timer);
l2cap_chan_del(sk, 0);
bh_unlock_sock(sk);
@@ -2996,9 +3055,23 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
switch (rx_control & L2CAP_CTRL_SUPERVISE) {
case L2CAP_SUPER_RCV_READY:
- pi->expected_ack_seq = __get_reqseq(rx_control);
- l2cap_drop_acked_frames(sk);
- l2cap_ertm_send(sk);
+ if (rx_control & L2CAP_CTRL_POLL) {
+ u16 control = L2CAP_CTRL_FINAL;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+ } else if (rx_control & L2CAP_CTRL_FINAL) {
+ if (pi->conn_state & L2CAP_CONN_WAIT_ACK)
+ break;
+
+ pi->conn_state &= !L2CAP_CONN_WAIT_ACK;
+ del_timer(&pi->monitor_timer);
+
+ if (pi->unacked_frames > 0)
+ __mod_retrans_timer();
+ } else {
+ pi->expected_ack_seq = __get_reqseq(rx_control);
+ l2cap_drop_acked_frames(sk);
+ l2cap_ertm_send(sk);
+ }
break;
case L2CAP_SUPER_REJECT:
--
1.6.3.3
When receiving an I-frame with unexpected txSeq, receiver side start the
recovery procedure by sending a REJ S-frame to the transmitter side. So
the transmitter can re-send the lost I-frame.
This patch just adds a basic support for retransmission, it doesn't
mean that ERTM now has full support to packet retransmission.
Signed-off-by: Gustavo F. Padovan <[email protected]>
---
include/net/bluetooth/l2cap.h | 1 +
net/bluetooth/l2cap.c | 57 +++++++++++++++++++++++++++++++----------
2 files changed, 44 insertions(+), 14 deletions(-)
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 9189328..c54b72a 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -352,6 +352,7 @@ struct l2cap_pinfo {
#define L2CAP_CONF_MAX_CONF_RSP 2
#define L2CAP_CONN_SAR_SDU 0x01
+#define L2CAP_CONN_UNDER_REJ 0x02
static inline int l2cap_tx_window_full(struct sock *sk)
{
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 16c448d..918cc15 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -2956,22 +2956,36 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len);
- if (tx_seq != pi->expected_tx_seq)
- return -EINVAL;
+ if (tx_seq == pi->expected_tx_seq) {
+ if (pi->conn_state & L2CAP_CONN_UNDER_REJ)
+ pi->conn_state &= ~L2CAP_CONN_UNDER_REJ;
- err = l2cap_sar_reassembly_sdu(sk, skb, rx_control, tx_seq);
- if (err < 0)
- return err;
+ err = l2cap_sar_reassembly_sdu(sk, skb, rx_control, tx_seq);
+ if (err < 0)
+ return err;
+
+ pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
+ pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
+ if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
+ tx_control |= L2CAP_SUPER_RCV_READY;
+ tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ goto send;
+ }
+ } else {
+ /* Unexpected txSeq. Send a REJ S-frame */
+ kfree_skb(skb);
+ if (!(pi->conn_state & L2CAP_CONN_UNDER_REJ)) {
+ tx_control |= L2CAP_SUPER_REJECT;
+ tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ pi->conn_state |= L2CAP_CONN_UNDER_REJ;
- pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
- pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
- if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
- tx_control |= L2CAP_CTRL_FRAME_TYPE;
- tx_control |= L2CAP_SUPER_RCV_READY;
- tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
- err = l2cap_send_sframe(pi, tx_control);
+ goto send;
+ }
}
- return err;
+ return 0;
+
+send:
+ return l2cap_send_sframe(pi, tx_control);
}
static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
@@ -2987,8 +3001,18 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
l2cap_ertm_send(sk);
break;
- case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_REJECT:
+ pi->expected_ack_seq = __get_reqseq(rx_control);
+ l2cap_drop_acked_frames(sk);
+
+ sk->sk_send_head = TX_QUEUE(sk)->next;
+ pi->next_tx_seq = pi->expected_ack_seq;
+
+ l2cap_ertm_send(sk);
+
+ break;
+
+ case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_SELECT_REJECT:
break;
}
@@ -3035,6 +3059,11 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
if (__is_sar_start(control))
len -= 2;
+ /*
+ * We can just drop the corrupted I-frame here.
+ * Receiver will miss it and start proper recovery
+ * procedures and ask retransmission.
+ */
if (len > L2CAP_DEFAULT_MAX_PDU_SIZE)
goto drop;
--
1.6.3.3