Bluetooth: LE advertising cache

This patch implements the LE advertising cache. It stores sensitive
information (bdaddr and bdaddr_type so far) gathered from LE
advertising report events.

Only advertising entries from connectables devices are added to the
cache.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

2 files changed, 77 insertions, 0 deletions

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 6c994c004d15..10dfb85ad6a1 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -89,6 +89,12 @@ struct oob_data {
         u8 randomizer[16];
 };
 
+struct adv_entry {
+        struct list_head list;
+        bdaddr_t bdaddr;
+        u8 bdaddr_type;
+};
+
 #define NUM_REASSEMBLY 4
 struct hci_dev {
         struct list_head list;
@@ -181,6 +187,8 @@ struct hci_dev {
 
         struct list_head        remote_oob_data;
 
+        struct list_head        adv_entries;
+
         struct hci_dev_stats    stat;
 
         struct sk_buff_head     driver_init;
@@ -527,6 +535,11 @@ int hci_add_remote_oob_data(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 *hash,
                                                                 u8 *randomizer);
 int hci_remove_remote_oob_data(struct hci_dev *hdev, bdaddr_t *bdaddr);
 
+int hci_adv_entries_clear(struct hci_dev *hdev);
+struct adv_entry *hci_find_adv_entry(struct hci_dev *hdev, bdaddr_t *bdaddr);
+int hci_add_adv_entry(struct hci_dev *hdev,
+                                        struct hci_ev_le_advertising_info *ev);
+
 void hci_del_off_timer(struct hci_dev *hdev);
 
 void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 815269b07f20..cc40f221f5e7 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1202,6 +1202,67 @@ int hci_add_remote_oob_data(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 *hash,
         return 0;
 }
 
+int hci_adv_entries_clear(struct hci_dev *hdev)
+{
+        struct adv_entry *entry, *tmp;
+
+        list_for_each_entry_safe(entry, tmp, &hdev->adv_entries, list) {
+                list_del(&entry->list);
+                kfree(entry);
+        }
+
+        BT_DBG("%s adv cache cleared", hdev->name);
+
+        return 0;
+}
+
+struct adv_entry *hci_find_adv_entry(struct hci_dev *hdev, bdaddr_t *bdaddr)
+{
+        struct adv_entry *entry;
+
+        list_for_each_entry(entry, &hdev->adv_entries, list)
+                if (bacmp(bdaddr, &entry->bdaddr) == 0)
+                        return entry;
+
+        return NULL;
+}
+
+static inline int is_connectable_adv(u8 evt_type)
+{
+        if (evt_type == ADV_IND || evt_type == ADV_DIRECT_IND)
+                return 1;
+
+        return 0;
+}
+
+int hci_add_adv_entry(struct hci_dev *hdev,
+                                        struct hci_ev_le_advertising_info *ev)
+{
+        struct adv_entry *entry;
+
+        if (!is_connectable_adv(ev->evt_type))
+                return -EINVAL;
+
+        /* Only new entries should be added to adv_entries. So, if
+         * bdaddr was found, don't add it. */
+        if (hci_find_adv_entry(hdev, &ev->bdaddr))
+                return 0;
+
+        entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
+        if (!entry)
+                return -ENOMEM;
+
+        bacpy(&entry->bdaddr, &ev->bdaddr);
+        entry->bdaddr_type = ev->bdaddr_type;
+
+        list_add(&entry->list, &hdev->adv_entries);
+
+        BT_DBG("%s adv entry added: address %s type %u", hdev->name,
+                                batostr(&entry->bdaddr), entry->bdaddr_type);
+
+        return 0;
+}
+
 /* Register HCI device */
 int hci_register_dev(struct hci_dev *hdev)
 {
@@ -1268,6 +1329,8 @@ int hci_register_dev(struct hci_dev *hdev)
 
         INIT_LIST_HEAD(&hdev->remote_oob_data);
 
+        INIT_LIST_HEAD(&hdev->adv_entries);
+
         INIT_WORK(&hdev->power_on, hci_power_on);
         INIT_WORK(&hdev->power_off, hci_power_off);
         setup_timer(&hdev->off_timer, hci_auto_off, (unsigned long) hdev);
@@ -1348,6 +1411,7 @@ int hci_unregister_dev(struct hci_dev *hdev)
         hci_uuids_clear(hdev);
         hci_link_keys_clear(hdev);
         hci_remote_oob_data_clear(hdev);
+        hci_adv_entries_clear(hdev);
         hci_dev_unlock_bh(hdev);
 
         __hci_dev_put(hdev);