When L2CAP PDUs are longer than the HCI MTU, they are stored in fragmented skbuffs. This adds a function to calculate the FCS on any skbuff (fragmented or not), and replaces direct calls to crc16 with calls to the new apply_fcs() function.
Signed-off-by: Mat Martineau <[email protected]> --- net/bluetooth/l2cap.c | 57 ++++++++++++++++++++++++++++++++---------------- 1 files changed, 38 insertions(+), 19 deletions(-) diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index 8d362d7..5e78c18 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -351,6 +351,33 @@ static inline u8 l2cap_get_ident(struct l2cap_conn *conn) return id; } +static void apply_fcs(struct sk_buff *skb) +{ + size_t len; + u16 partial_crc; + struct sk_buff *iter; + struct sk_buff *final_frag = skb; + + if (skb_has_frags(skb)) + len = skb_headlen(skb); + else + len = skb->len - L2CAP_FCS_SIZE; + + partial_crc = crc16(0, (u8 *) skb->data, len); + + skb_walk_frags(skb, iter) { + len = iter->len; + if (!iter->next) + len -= L2CAP_FCS_SIZE; + + partial_crc = crc16(partial_crc, iter->data, len); + final_frag = iter; + } + + put_unaligned_le16(partial_crc, + final_frag->data + final_frag->len - L2CAP_FCS_SIZE); +} + static inline void l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len, void *data) { struct sk_buff *skb = l2cap_build_cmd(conn, code, ident, len, data); @@ -401,10 +428,8 @@ static inline void l2cap_send_sframe(struct l2cap_pinfo *pi, u16 control) lh->cid = cpu_to_le16(pi->dcid); put_unaligned_le16(control, skb_put(skb, 2)); - if (pi->fcs == L2CAP_FCS_CRC16) { - u16 fcs = crc16(0, (u8 *)lh, count - 2); - put_unaligned_le16(fcs, skb_put(skb, 2)); - } + if (pi->fcs == L2CAP_FCS_CRC16) + apply_fcs(skb); hci_send_acl(pi->conn->hcon, skb, 0); } @@ -1458,7 +1483,7 @@ static void l2cap_streaming_send(struct sock *sk) { struct sk_buff *skb, *tx_skb; struct l2cap_pinfo *pi = l2cap_pi(sk); - u16 control, fcs; + u16 control; while ((skb = sk->sk_send_head)) { tx_skb = skb_clone(skb, GFP_ATOMIC); @@ -1467,10 +1492,8 @@ static void l2cap_streaming_send(struct sock *sk) control |= pi->next_tx_seq << L2CAP_CTRL_TXSEQ_SHIFT; put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE); - if (pi->fcs == L2CAP_FCS_CRC16) { - fcs = crc16(0, (u8 *)tx_skb->data, tx_skb->len - 2); - put_unaligned_le16(fcs, tx_skb->data + tx_skb->len - 2); - } + if (pi->fcs == L2CAP_FCS_CRC16) + apply_fcs(tx_skb); l2cap_do_send(sk, tx_skb); @@ -1490,7 +1513,7 @@ static void l2cap_retransmit_one_frame(struct sock *sk, u8 tx_seq) { struct l2cap_pinfo *pi = l2cap_pi(sk); struct sk_buff *skb, *tx_skb; - u16 control, fcs; + u16 control; skb = skb_peek(TX_QUEUE(sk)); if (!skb) @@ -1525,10 +1548,8 @@ static void l2cap_retransmit_one_frame(struct sock *sk, u8 tx_seq) put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE); - if (pi->fcs == L2CAP_FCS_CRC16) { - fcs = crc16(0, (u8 *)tx_skb->data, tx_skb->len - 2); - put_unaligned_le16(fcs, tx_skb->data + tx_skb->len - 2); - } + if (pi->fcs == L2CAP_FCS_CRC16) + apply_fcs(tx_skb); l2cap_do_send(sk, tx_skb); } @@ -1537,7 +1558,7 @@ static int l2cap_ertm_send(struct sock *sk) { struct sk_buff *skb, *tx_skb; struct l2cap_pinfo *pi = l2cap_pi(sk); - u16 control, fcs; + u16 control; int nsent = 0; if (sk->sk_state != BT_CONNECTED) @@ -1567,10 +1588,8 @@ static int l2cap_ertm_send(struct sock *sk) put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE); - if (pi->fcs == L2CAP_FCS_CRC16) { - fcs = crc16(0, (u8 *)skb->data, tx_skb->len - 2); - put_unaligned_le16(fcs, skb->data + tx_skb->len - 2); - } + if (pi->fcs == L2CAP_FCS_CRC16) + apply_fcs(tx_skb); l2cap_do_send(sk, tx_skb); -- 1.7.1 -- Mat Martineau Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
