Bluetooth: Enable Streaming Mode for L2CAP

Streaming Mode is helpful for the Bluetooth streaming based profiles, such
as A2DP. It doesn't have any error control or flow control.

Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 97172f7..7f835e7 100644 (file)
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1245,6 +1245,39 @@ static inline int l2cap_do_send(struct sock *sk, struct sk_buff *skb)
        return err;
 }
 
+static int l2cap_streaming_send(struct sock *sk)
+{
+       struct sk_buff *skb, *tx_skb;
+       struct l2cap_pinfo *pi = l2cap_pi(sk);
+       u16 control;
+       int err;
+
+       while ((skb = sk->sk_send_head)) {
+               tx_skb = skb_clone(skb, GFP_ATOMIC);
+
+               control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
+               control |= pi->next_tx_seq << L2CAP_CTRL_TXSEQ_SHIFT;
+               put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE);
+
+               err = l2cap_do_send(sk, tx_skb);
+               if (err < 0) {
+                       l2cap_send_disconn_req(pi->conn, sk);
+                       return err;
+               }
+
+               pi->next_tx_seq = (pi->next_tx_seq + 1) % 64;
+
+               if (skb_queue_is_last(TX_QUEUE(sk), skb))
+                       sk->sk_send_head = NULL;
+               else
+                       sk->sk_send_head = skb_queue_next(TX_QUEUE(sk), skb);
+
+               skb = skb_dequeue(TX_QUEUE(sk));
+               kfree_skb(skb);
+       }
+       return 0;
+}
+
 static int l2cap_ertm_send(struct sock *sk)
 {
        struct sk_buff *skb, *tx_skb;
@@ -1383,7 +1416,7 @@ 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, u16 sdulen)
+static struct sk_buff *l2cap_create_iframe_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;
@@ -1429,7 +1462,7 @@ static inline int l2cap_sar_segment_sdu(struct sock *sk, struct msghdr *msg, siz
 
        __skb_queue_head_init(&sar_queue);
        control = L2CAP_SDU_START;
-       skb = l2cap_create_ertm_pdu(sk, msg, pi->max_pdu_size, control, len);
+       skb = l2cap_create_iframe_pdu(sk, msg, pi->max_pdu_size, control, len);
        if (IS_ERR(skb))
                return PTR_ERR(skb);
 
@@ -1449,7 +1482,7 @@ static inline int l2cap_sar_segment_sdu(struct sock *sk, struct msghdr *msg, siz
                        buflen = len;
                }
 
-               skb = l2cap_create_ertm_pdu(sk, msg, buflen, control, 0);
+               skb = l2cap_create_iframe_pdu(sk, msg, buflen, control, 0);
                if (IS_ERR(skb)) {
                        skb_queue_purge(&sar_queue);
                        return PTR_ERR(skb);
@@ -1518,10 +1551,11 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
                break;
 
        case L2CAP_MODE_ERTM:
+       case L2CAP_MODE_STREAMING:
                /* Entire SDU fits into one PDU */
                if (len <= pi->max_pdu_size) {
                        control = L2CAP_SDU_UNSEGMENTED;
-                       skb = l2cap_create_ertm_pdu(sk, msg, len, control, 0);
+                       skb = l2cap_create_iframe_pdu(sk, msg, len, control, 0);
                        if (IS_ERR(skb)) {
                                err = PTR_ERR(skb);
                                goto done;
@@ -1536,7 +1570,11 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
                                goto done;
                }
 
-               err = l2cap_ertm_send(sk);
+               if (pi->mode == L2CAP_MODE_STREAMING)
+                       err = l2cap_streaming_send(sk);
+               else
+                       err = l2cap_ertm_send(sk);
+
                if (!err)
                        err = len;
                break;
@@ -2050,7 +2088,7 @@ static int l2cap_mode_supported(__u8 mode, __u32 feat_mask)
 {
        u32 local_feat_mask = l2cap_feat_mask;
        if (enable_ertm)
-               local_feat_mask |= L2CAP_FEAT_ERTM;
+               local_feat_mask |= L2CAP_FEAT_ERTM | L2CAP_FEAT_STREAMING;
 
        switch (mode) {
        case L2CAP_MODE_ERTM:
@@ -2771,7 +2809,7 @@ static inline int l2cap_information_req(struct l2cap_conn *conn, struct l2cap_cm
                rsp->type   = cpu_to_le16(L2CAP_IT_FEAT_MASK);
                rsp->result = cpu_to_le16(L2CAP_IR_SUCCESS);
                if (enable_ertm)
-                       feat_mask |= L2CAP_FEAT_ERTM;
+                       feat_mask |= L2CAP_FEAT_ERTM | L2CAP_FEAT_STREAMING;
                put_unaligned(cpu_to_le32(feat_mask), (__le32 *) rsp->data);
                l2cap_send_cmd(conn, cmd->ident,
                                        L2CAP_INFO_RSP, sizeof(buf), buf);
@@ -3096,7 +3134,9 @@ 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;
+       struct l2cap_pinfo *pi;
        u16 control, len;
+       u8 tx_seq;
        int err;
 
        sk = l2cap_get_chan_by_scid(&conn->chan_list, cid);
@@ -3105,19 +3145,21 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
                goto drop;
        }
 
+       pi = l2cap_pi(sk);
+
        BT_DBG("sk %p, len %d", sk, skb->len);
 
        if (sk->sk_state != BT_CONNECTED)
                goto drop;
 
-       switch (l2cap_pi(sk)->mode) {
+       switch (pi->mode) {
        case L2CAP_MODE_BASIC:
                /* If socket recv buffers overflows we drop data here
                 * which is *bad* because L2CAP has to be reliable.
                 * But we don't have any other choice. L2CAP doesn't
                 * provide flow control mechanism. */
 
-               if (l2cap_pi(sk)->imtu < skb->len)
+               if (pi->imtu < skb->len)
                        goto drop;
 
                if (!sock_queue_rcv_skb(sk, skb))
@@ -3149,6 +3191,28 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
                        goto done;
                break;
 
+       case L2CAP_MODE_STREAMING:
+               control = get_unaligned_le16(skb->data);
+               skb_pull(skb, 2);
+               len = skb->len;
+
+               if (__is_sar_start(control))
+                       len -= 2;
+
+               if (len > L2CAP_DEFAULT_MAX_PDU_SIZE || __is_sframe(control))
+                       goto drop;
+
+               tx_seq = __get_txseq(control);
+
+               if (pi->expected_tx_seq == tx_seq)
+                       pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
+               else
+                       pi->expected_tx_seq = tx_seq + 1;
+
+               err = l2cap_sar_reassembly_sdu(sk, skb, control);
+
+               goto done;
+
        default:
                BT_DBG("sk %p: bad mode 0x%2.2x", sk, l2cap_pi(sk)->mode);
                break;