Bluetooth: A2MP: Process A2MP messages

Implement basic processing for AMP Manager Protocol (A2MP).

Example below shows processing unrecognized command.
...
> ACL data: handle 11 flags 0x02 dlen 12
    A2MP: code 0x00 ident 3 len 0
< ACL data: handle 11 flags 0x00 dlen 14
    A2MP: Command Reject: reason (0) - Command not recognized
...

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

1 files changed, 65 insertions, 0 deletions

diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index f7c710cacf44..0726c9fe005c 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -63,6 +63,70 @@ static void a2mp_send(struct amp_mgr *mgr, u8 code, u8 ident, u16 len,
         kfree(cmd);
 }
 
+/* Handle A2MP signalling */
+static int a2mp_chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
+{
+        struct a2mp_cmd *hdr = (void *) skb->data;
+        struct amp_mgr *mgr = chan->data;
+        int err = 0;
+
+        amp_mgr_get(mgr);
+
+        while (skb->len >= sizeof(*hdr)) {
+                struct a2mp_cmd *hdr = (void *) skb->data;
+                u16 len = le16_to_cpu(hdr->len);
+
+                BT_DBG("code 0x%02x id %d len %d", hdr->code, hdr->ident, len);
+
+                skb_pull(skb, sizeof(*hdr));
+
+                if (len > skb->len || !hdr->ident) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                mgr->ident = hdr->ident;
+
+                switch (hdr->code) {
+                case A2MP_COMMAND_REJ:
+                case A2MP_DISCOVER_REQ:
+                case A2MP_CHANGE_NOTIFY:
+                case A2MP_GETINFO_REQ:
+                case A2MP_GETAMPASSOC_REQ:
+                case A2MP_CREATEPHYSLINK_REQ:
+                case A2MP_DISCONNPHYSLINK_REQ:
+                case A2MP_CHANGE_RSP:
+                case A2MP_DISCOVER_RSP:
+                case A2MP_GETINFO_RSP:
+                case A2MP_GETAMPASSOC_RSP:
+                case A2MP_CREATEPHYSLINK_RSP:
+                case A2MP_DISCONNPHYSLINK_RSP:
+                default:
+                        BT_ERR("Unknown A2MP sig cmd 0x%2.2x", hdr->code);
+                        err = -EINVAL;
+                        break;
+                }
+        }
+
+        if (err) {
+                struct a2mp_cmd_rej rej;
+                rej.reason = __constant_cpu_to_le16(0);
+
+                BT_DBG("Send A2MP Rej: cmd 0x%2.2x err %d", hdr->code, err);
+
+                a2mp_send(mgr, A2MP_COMMAND_REJ, hdr->ident, sizeof(rej),
+                          &rej);
+        }
+
+        /* Always free skb and return success error code to prevent
+           from sending L2CAP Disconnect over A2MP channel */
+        kfree_skb(skb);
+
+        amp_mgr_put(mgr);
+
+        return 0;
+}
+
 static void a2mp_chan_close_cb(struct l2cap_chan *chan)
 {
         l2cap_chan_destroy(chan);
@@ -112,6 +176,7 @@ static void a2mp_chan_no_ready(struct l2cap_chan *chan)
 
 static struct l2cap_ops a2mp_chan_ops = {
         .name = "L2CAP A2MP channel",
+        .recv = a2mp_chan_recv_cb,
         .close = a2mp_chan_close_cb,
         .state_change = a2mp_chan_state_change_cb,
         .alloc_skb = a2mp_chan_alloc_skb_cb,