Bluetooth: Functions for handling ERTM control fields

These functions encode or decode ERTM control fields (extended or
enhanced) to or from the new l2cap_ctrl structure.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Acked-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 113 insertions, 0 deletions

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 041ebed9e647..913cec3e52d7 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -786,6 +786,117 @@ static inline void l2cap_send_rr_or_rnr(struct l2cap_chan *chan, u32 control)
         l2cap_send_sframe(chan, control);
 }
 
+static u16 __pack_enhanced_control(struct l2cap_ctrl *control)
+{
+        u16 packed;
+
+        packed = control->reqseq << L2CAP_CTRL_REQSEQ_SHIFT;
+        packed |= control->final << L2CAP_CTRL_FINAL_SHIFT;
+
+        if (control->sframe) {
+                packed |= control->poll << L2CAP_CTRL_POLL_SHIFT;
+                packed |= control->super << L2CAP_CTRL_SUPER_SHIFT;
+                packed |= L2CAP_CTRL_FRAME_TYPE;
+        } else {
+                packed |= control->sar << L2CAP_CTRL_SAR_SHIFT;
+                packed |= control->txseq << L2CAP_CTRL_TXSEQ_SHIFT;
+        }
+
+        return packed;
+}
+
+static void __unpack_enhanced_control(u16 enh, struct l2cap_ctrl *control)
+{
+        control->reqseq = (enh & L2CAP_CTRL_REQSEQ) >> L2CAP_CTRL_REQSEQ_SHIFT;
+        control->final = (enh & L2CAP_CTRL_FINAL) >> L2CAP_CTRL_FINAL_SHIFT;
+
+        if (enh & L2CAP_CTRL_FRAME_TYPE) {
+                /* S-Frame */
+                control->sframe = 1;
+                control->poll = (enh & L2CAP_CTRL_POLL) >> L2CAP_CTRL_POLL_SHIFT;
+                control->super = (enh & L2CAP_CTRL_SUPERVISE) >> L2CAP_CTRL_SUPER_SHIFT;
+
+                control->sar = 0;
+                control->txseq = 0;
+        } else {
+                /* I-Frame */
+                control->sframe = 0;
+                control->sar = (enh & L2CAP_CTRL_SAR) >> L2CAP_CTRL_SAR_SHIFT;
+                control->txseq = (enh & L2CAP_CTRL_TXSEQ) >> L2CAP_CTRL_TXSEQ_SHIFT;
+
+                control->poll = 0;
+                control->super = 0;
+        }
+}
+
+static u32 __pack_extended_control(struct l2cap_ctrl *control)
+{
+        u32 packed;
+
+        packed = control->reqseq << L2CAP_EXT_CTRL_REQSEQ_SHIFT;
+        packed |= control->final << L2CAP_EXT_CTRL_FINAL_SHIFT;
+
+        if (control->sframe) {
+                packed |= control->poll << L2CAP_EXT_CTRL_POLL_SHIFT;
+                packed |= control->super << L2CAP_EXT_CTRL_SUPER_SHIFT;
+                packed |= L2CAP_EXT_CTRL_FRAME_TYPE;
+        } else {
+                packed |= control->sar << L2CAP_EXT_CTRL_SAR_SHIFT;
+                packed |= control->txseq << L2CAP_EXT_CTRL_TXSEQ_SHIFT;
+        }
+
+        return packed;
+}
+
+static void __unpack_extended_control(u32 ext, struct l2cap_ctrl *control)
+{
+        control->reqseq = (ext & L2CAP_EXT_CTRL_REQSEQ) >> L2CAP_EXT_CTRL_REQSEQ_SHIFT;
+        control->final = (ext & L2CAP_EXT_CTRL_FINAL) >> L2CAP_EXT_CTRL_FINAL_SHIFT;
+
+        if (ext & L2CAP_EXT_CTRL_FRAME_TYPE) {
+                /* S-Frame */
+                control->sframe = 1;
+                control->poll = (ext & L2CAP_EXT_CTRL_POLL) >> L2CAP_EXT_CTRL_POLL_SHIFT;
+                control->super = (ext & L2CAP_EXT_CTRL_SUPERVISE) >> L2CAP_EXT_CTRL_SUPER_SHIFT;
+
+                control->sar = 0;
+                control->txseq = 0;
+        } else {
+                /* I-Frame */
+                control->sframe = 0;
+                control->sar = (ext & L2CAP_EXT_CTRL_SAR) >> L2CAP_EXT_CTRL_SAR_SHIFT;
+                control->txseq = (ext & L2CAP_EXT_CTRL_TXSEQ) >> L2CAP_EXT_CTRL_TXSEQ_SHIFT;
+
+                control->poll = 0;
+                control->super = 0;
+        }
+}
+
+static inline void __unpack_control(struct l2cap_chan *chan,
+                                    struct sk_buff *skb)
+{
+        if (test_bit(FLAG_EXT_CTRL, &chan->flags)) {
+                __unpack_extended_control(get_unaligned_le32(skb->data),
+                                          &bt_cb(skb)->control);
+        } else {
+                __unpack_enhanced_control(get_unaligned_le16(skb->data),
+                                          &bt_cb(skb)->control);
+        }
+}
+
+static inline void __pack_control(struct l2cap_chan *chan,
+                                  struct l2cap_ctrl *control,
+                                  struct sk_buff *skb)
+{
+        if (test_bit(FLAG_EXT_CTRL, &chan->flags)) {
+                put_unaligned_le32(__pack_extended_control(control),
+                                   skb->data + L2CAP_HDR_SIZE);
+        } else {
+                put_unaligned_le16(__pack_enhanced_control(control),
+                                   skb->data + L2CAP_HDR_SIZE);
+        }
+}
+
 static inline int __l2cap_no_conn_pending(struct l2cap_chan *chan)
 {
         return !test_bit(CONF_CONNECT_PEND, &chan->conf_state);
@@ -4359,6 +4470,8 @@ static int l2cap_ertm_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
         u16 req_seq;
         int len, next_tx_seq_offset, req_seq_offset;
 
+        __unpack_control(chan, skb);
+
         control = __get_control(chan, skb->data);
         skb_pull(skb, __ctrl_size(chan));
         len = skb->len;