[Bluetooth] Add hci_recv_fragment() helper function

Most drivers must handle fragmented HCI data packets and events. This
patch adds a generic function for their reassembly to the Bluetooth
core layer and thus allows to shrink the complexity of the drivers.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

2 files changed, 98 insertions, 2 deletions

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index c0fc39620f36..7c78744ec0fd 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -109,6 +109,7 @@ struct hci_dev {
         struct sk_buff_head     cmd_q;
 
         struct sk_buff          *sent_cmd;
+        struct sk_buff          *reassembly[3];
 
         struct semaphore        req_lock;
         wait_queue_head_t       req_wait_q;
@@ -437,6 +438,8 @@ static inline int hci_recv_frame(struct sk_buff *skb)
         return 0;
 }
 
+int hci_recv_fragment(struct hci_dev *hdev, int type, void *data, int count);
+
 int hci_register_sysfs(struct hci_dev *hdev);
 void hci_unregister_sysfs(struct hci_dev *hdev);
 void hci_conn_add_sysfs(struct hci_conn *conn);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index aa4b56a8c3ea..9c71cffbc6b0 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -826,7 +826,7 @@ EXPORT_SYMBOL(hci_free_dev);
 int hci_register_dev(struct hci_dev *hdev)
 {
         struct list_head *head = &hci_dev_list, *p;
-        int id = 0;
+        int i, id = 0;
 
         BT_DBG("%p name %s type %d owner %p", hdev, hdev->name, hdev->type, hdev->owner);
 
@@ -865,6 +865,9 @@ int hci_register_dev(struct hci_dev *hdev)
         skb_queue_head_init(&hdev->cmd_q);
         skb_queue_head_init(&hdev->raw_q);
 
+        for (i = 0; i < 3; i++)
+                hdev->reassembly[i] = NULL;
+
         init_waitqueue_head(&hdev->req_wait_q);
         init_MUTEX(&hdev->req_lock);
 
@@ -889,6 +892,8 @@ EXPORT_SYMBOL(hci_register_dev);
 /* Unregister HCI device */
 int hci_unregister_dev(struct hci_dev *hdev)
 {
+        int i;
+
         BT_DBG("%p name %s type %d", hdev, hdev->name, hdev->type);
 
         hci_unregister_sysfs(hdev);
@@ -899,9 +904,13 @@ int hci_unregister_dev(struct hci_dev *hdev)
 
         hci_dev_do_close(hdev);
 
+        for (i = 0; i < 3; i++)
+                kfree_skb(hdev->reassembly[i]);
+
         hci_notify(hdev, HCI_DEV_UNREG);
 
         __hci_dev_put(hdev);
+
         return 0;
 }
 EXPORT_SYMBOL(hci_unregister_dev);
@@ -922,6 +931,90 @@ int hci_resume_dev(struct hci_dev *hdev)
 }
 EXPORT_SYMBOL(hci_resume_dev);
 
+/* Receive packet type fragment */
+#define __reassembly(hdev, type)  ((hdev)->reassembly[(type) - 2])
+
+int hci_recv_fragment(struct hci_dev *hdev, int type, void *data, int count)
+{
+        if (type < HCI_ACLDATA_PKT || type > HCI_EVENT_PKT)
+                return -EILSEQ;
+
+        while (count) {
+                struct sk_buff *skb = __reassembly(hdev, type);
+                struct { int expect; } *scb;
+                int len = 0;
+
+                if (!skb) {
+                        /* Start of the frame */
+
+                        switch (type) {
+                        case HCI_EVENT_PKT:
+                                if (count >= HCI_EVENT_HDR_SIZE) {
+                                        struct hci_event_hdr *h = data;
+                                        len = HCI_EVENT_HDR_SIZE + h->plen;
+                                } else
+                                        return -EILSEQ;
+                                break;
+
+                        case HCI_ACLDATA_PKT:
+                                if (count >= HCI_ACL_HDR_SIZE) {
+                                        struct hci_acl_hdr *h = data;
+                                        len = HCI_ACL_HDR_SIZE + __le16_to_cpu(h->dlen);
+                                } else
+                                        return -EILSEQ;
+                                break;
+
+                        case HCI_SCODATA_PKT:
+                                if (count >= HCI_SCO_HDR_SIZE) {
+                                        struct hci_sco_hdr *h = data;
+                                        len = HCI_SCO_HDR_SIZE + h->dlen;
+                                } else
+                                        return -EILSEQ;
+                                break;
+                        }
+
+                        skb = bt_skb_alloc(len, GFP_ATOMIC);
+                        if (!skb) {
+                                BT_ERR("%s no memory for packet", hdev->name);
+                                return -ENOMEM;
+                        }
+
+                        skb->dev = (void *) hdev;
+                        bt_cb(skb)->pkt_type = type;
+        
+                        __reassembly(hdev, type) = skb;
+
+                        scb = (void *) skb->cb;
+                        scb->expect = len;
+                } else {
+                        /* Continuation */
+
+                        scb = (void *) skb->cb;
+                        len = scb->expect;
+                }
+
+                len = min(len, count);
+
+                memcpy(skb_put(skb, len), data, len);
+
+                scb->expect -= len;
+
+                if (scb->expect == 0) {
+                        /* Complete frame */
+
+                        __reassembly(hdev, type) = NULL;
+
+                        bt_cb(skb)->pkt_type = type;
+                        hci_recv_frame(skb);
+                }
+
+                count -= len; data += len;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(hci_recv_fragment);
+
 /* ---- Interface to upper protocols ---- */
 
 /* Register/Unregister protocols.
@@ -1029,7 +1122,7 @@ int hci_send_cmd(struct hci_dev *hdev, __u16 ogf, __u16 ocf, __u32 plen, void *p
 
         skb = bt_skb_alloc(len, GFP_ATOMIC);
         if (!skb) {
-                BT_ERR("%s Can't allocate memory for HCI command", hdev->name);
+                BT_ERR("%s no memory for command", hdev->name);
                 return -ENOMEM;
         }