2011-02-17 13:39:54

by Anderson Briglia

[permalink] [raw]
Subject: [RFCv2 2/4] Bluetooth: LE advertising info caching

From: Andre Guedes <[email protected]>

This patch implements a fixed-size circular list to store sensitive
information (bdaddr and bdaddr_type so far) gathered from LE
advertising report events.

The fixed-size circular list has max size equal to 64. Once the buffer
reaches its max size, new advertising entries will replace old ones.

Signed-off-by: Andre Guedes <[email protected]>
---
include/net/bluetooth/hci_core.h | 17 +++++++++
net/bluetooth/hci_core.c | 75 ++++++++++++++++++++++++++++++++++++++
net/bluetooth/hci_event.c | 5 +--
3 files changed, 94 insertions(+), 3 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 5114122..5992148 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -82,6 +82,18 @@ struct link_key {
u8 pin_len;
};

+struct adv_entry {
+ struct list_head list;
+ bdaddr_t bdaddr;
+ u8 bdaddr_type;
+};
+
+#define ADV_LIST_MAX_SIZE 64
+struct adv_list {
+ struct list_head list;
+ size_t size;
+};
+
#define NUM_REASSEMBLY 4
struct hci_dev {
struct list_head list;
@@ -171,6 +183,8 @@ struct hci_dev {

struct list_head link_keys;

+ struct adv_list adv_entries;
+
struct hci_dev_stats stat;

struct sk_buff_head driver_init;
@@ -504,6 +518,9 @@ int hci_add_link_key(struct hci_dev *hdev, int new_key, bdaddr_t *bdaddr,
u8 *key, u8 type, u8 pin_len);
int hci_remove_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr);

+struct adv_entry *hci_find_adv_entry(struct hci_dev *hdev, bdaddr_t *bdaddr);
+int hci_add_adv_entry(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 bdaddr_type);
+
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 013baf9..0d0598b 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1067,6 +1067,78 @@ int hci_remove_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)
return 0;
}

+static inline void hci_adv_entries_init(struct hci_dev *hdev)
+{
+ hdev->adv_entries.size = 0;
+ INIT_LIST_HEAD(&hdev->adv_entries.list);
+}
+
+static int hci_adv_entries_clear(struct hci_dev *hdev)
+{
+ struct list_head *p, *n;
+
+ list_for_each_safe(p, n, &hdev->adv_entries.list) {
+ struct adv_entry *entry;
+
+ entry = list_entry(p, struct adv_entry, list);
+
+ list_del(p);
+ kfree(entry);
+ }
+
+ hdev->adv_entries.size = 0;
+ return 0;
+
+}
+
+struct adv_entry *hci_find_adv_entry(struct hci_dev *hdev, bdaddr_t *bdaddr)
+{
+ struct list_head *p;
+
+ list_for_each(p, &hdev->adv_entries.list) {
+ struct adv_entry *k;
+
+ k = list_entry(p, struct adv_entry, list);
+
+ if (bacmp(bdaddr, &k->bdaddr) == 0)
+ return k;
+ }
+
+ return NULL;
+}
+
+int hci_add_adv_entry(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 bdaddr_type)
+{
+ struct adv_entry *entry;
+
+ entry = hci_find_adv_entry(hdev, bdaddr);
+ /* Only new entries should be added to adv_entries. So, if
+ * bdaddr was found, don't add it. */
+ if (entry)
+ return 0;
+
+ entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
+ if (!entry)
+ return -ENOMEM;
+
+ BT_DBG(": %s type %d", batostr(bdaddr), bdaddr_type);
+
+ bacpy(&entry->bdaddr, bdaddr);
+ entry->bdaddr_type = bdaddr_type;
+
+ if (hdev->adv_entries.size < ADV_LIST_MAX_SIZE) {
+ hdev->adv_entries.size += 1;
+ } else {
+ struct list_head *head = &hdev->adv_entries.list;
+ struct list_head *tail = head->prev;
+ list_del(tail);
+ }
+
+ list_add(&entry->list, &hdev->adv_entries.list);
+
+ return 0;
+}
+
static struct crypto_blkcipher *alloc_cypher(void)
{
#ifndef CONFIG_BT_SMP
@@ -1137,6 +1209,8 @@ int hci_register_dev(struct hci_dev *hdev)

INIT_LIST_HEAD(&hdev->link_keys);

+ hci_adv_entries_init(hdev);
+
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);
@@ -1224,6 +1298,7 @@ int hci_unregister_dev(struct hci_dev *hdev)
hci_blacklist_clear(hdev);
hci_uuids_clear(hdev);
hci_link_keys_clear(hdev);
+ hci_adv_entries_clear(hdev);
hci_dev_unlock_bh(hdev);

__hci_dev_put(hdev);
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 1c8d888..3111648 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2507,12 +2507,11 @@ static inline void hci_le_adv_report_evt(struct hci_dev *hdev,
num_reports = skb->data[0];

ev = (void *) &skb->data[1];
-
- BT_DBG("adv from: %s", batostr(&ev->bdaddr));
+ hci_add_adv_entry(hdev, &ev->bdaddr, ev->bdaddr_type);

for (i = 1; i < num_reports; i++) {
ev = (void *) (ev->data + ev->length + 1);
- BT_DBG("adv from: %s", batostr(&ev->bdaddr));
+ hci_add_adv_entry(hdev, &ev->bdaddr, ev->bdaddr_type);
}
}

--
1.7.1