[PATCH 1/3] Bluetooth: Send device found event on name resolve failure

[PATCH 1/3] Bluetooth: Send device found event on name resolve failure

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

Introducing CONFIRM_NAME_FAILED flag that will be sent together with
device found event on name resolve failure. This will provide the
userspace with an information so it can decide not to resolve the
name for these devices in the future.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>

---
Hi maintainers,

This is the patch series for remote name request as was discussed here.
https://patchwork.kernel.org/project/bluetooth/patch/20211028191805.1.I35b7f3a496f834de6b43a32f94b6160cb1467c94@changeid/
Please also review the corresponding userspace change.

Thanks,
Archie

 include/net/bluetooth/mgmt.h |  1 +
 net/bluetooth/hci_event.c    | 11 ++++-------
 net/bluetooth/mgmt.c         | 11 ++++++++---
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
index 23a0524061b7..113438f295bf 100644
--- a/include/net/bluetooth/mgmt.h
+++ b/include/net/bluetooth/mgmt.h
@@ -940,6 +940,7 @@ struct mgmt_ev_auth_failed {
 #define MGMT_DEV_FOUND_LEGACY_PAIRING  0x02
 #define MGMT_DEV_FOUND_NOT_CONNECTABLE 0x04
 #define MGMT_DEV_FOUND_INITIATED_CONN  0x08
+#define MGMT_DEV_FOUND_CONFIRM_NAME_FAILED 0x10
 
 #define MGMT_EV_DEVICE_FOUND		0x0012
 struct mgmt_ev_device_found {
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index d4b75a6cfeee..2de3080659f9 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2175,13 +2175,10 @@ static void hci_check_pending_name(struct hci_dev *hdev, struct hci_conn *conn,
 		return;
 
 	list_del(&e->list);
-	if (name) {
-		e->name_state = NAME_KNOWN;
-		mgmt_remote_name(hdev, bdaddr, ACL_LINK, 0x00,
-				 e->data.rssi, name, name_len);
-	} else {
-		e->name_state = NAME_NOT_KNOWN;
-	}
+
+	e->name_state = name ? NAME_KNOWN : NAME_NOT_KNOWN;
+	mgmt_remote_name(hdev, bdaddr, ACL_LINK, 0x00, e->data.rssi,
+			 name, name_len);
 
 	if (hci_resolve_next_name(hdev))
 		return;
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 06384d761928..c1d6fbc19207 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -9615,7 +9615,8 @@ void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 {
 	struct mgmt_ev_device_found *ev;
 	char buf[sizeof(*ev) + HCI_MAX_NAME_LENGTH + 2];
-	u16 eir_len;
+	u16 eir_len = 0;
+	u32 flags = 0;
 
 	ev = (struct mgmt_ev_device_found *) buf;
 
@@ -9625,10 +9626,14 @@ void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 	ev->addr.type = link_to_bdaddr(link_type, addr_type);
 	ev->rssi = rssi;
 
-	eir_len = eir_append_data(ev->eir, 0, EIR_NAME_COMPLETE, name,
-				  name_len);
+	if (name)
+		eir_len = eir_append_data(ev->eir, 0, EIR_NAME_COMPLETE, name,
+					  name_len);
+	else
+		flags |= MGMT_DEV_FOUND_CONFIRM_NAME_FAILED;
 
 	ev->eir_len = cpu_to_le16(eir_len);
+	ev->flags = cpu_to_le32(flags);
 
 	mgmt_event(MGMT_EV_DEVICE_FOUND, hdev, ev, sizeof(*ev) + eir_len, NULL);
 }
-- 
2.34.0.rc0.344.g81b53c2807-goog

[PATCH 2/3] Bluetooth: Add "DONT_CARE" to remote name inquiry

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

With this patch, the user space can specify DONT_CARE when sending
confirm_name MGMT command. The kernel then will not attempt to perform
remote name request. In practice, we will treat them the same as if
the user space specified NAME_KNOWN instead.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>

---

 include/net/bluetooth/hci_core.h | 1 +
 include/net/bluetooth/mgmt.h     | 6 +++++-
 net/bluetooth/hci_core.c         | 1 +
 net/bluetooth/mgmt.c             | 5 ++++-
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index b5f061882c10..eb08dd502f2a 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -56,6 +56,7 @@ struct inquiry_entry {
 		NAME_NEEDED,
 		NAME_PENDING,
 		NAME_KNOWN,
+		NAME_DONT_CARE,		/* Don't know but don't want to know */
 	} name_state;
 	__u32			timestamp;
 	struct inquiry_data	data;
diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
index 113438f295bf..30d0415c29c9 100644
--- a/include/net/bluetooth/mgmt.h
+++ b/include/net/bluetooth/mgmt.h
@@ -352,10 +352,14 @@ struct mgmt_cp_stop_discovery {
 } __packed;
 #define MGMT_STOP_DISCOVERY_SIZE	1
 
+#define MGMT_CONFIRM_NAME_UNKNOWN	0
+#define MGMT_CONFIRM_NAME_KNOWN		1
+#define MGMT_CONFIRM_NAME_DONT_CARE	2
+
 #define MGMT_OP_CONFIRM_NAME		0x0025
 struct mgmt_cp_confirm_name {
 	struct mgmt_addr_info addr;
-	__u8	name_known;
+	__u8	name_state;
 } __packed;
 #define MGMT_CONFIRM_NAME_SIZE		(MGMT_ADDR_INFO_SIZE + 1)
 struct mgmt_rp_confirm_name {
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index fdc0dcf8ee36..90064dbbba5f 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -304,6 +304,7 @@ u32 hci_inquiry_cache_update(struct hci_dev *hdev, struct inquiry_data *data,
 
 update:
 	if (name_known && ie->name_state != NAME_KNOWN &&
+	    ie->name_state != NAME_DONT_CARE &&
 	    ie->name_state != NAME_PENDING) {
 		ie->name_state = NAME_KNOWN;
 		list_del(&ie->list);
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index c1d6fbc19207..e887de6f411e 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -5531,9 +5531,12 @@ static int confirm_name(struct sock *sk, struct hci_dev *hdev, void *data,
 		goto failed;
 	}
 
-	if (cp->name_known) {
+	if (cp->name_state == MGMT_CONFIRM_NAME_KNOWN) {
 		e->name_state = NAME_KNOWN;
 		list_del(&e->list);
+	} else if (cp->name_state == MGMT_CONFIRM_NAME_DONT_CARE) {
+		e->name_state = NAME_DONT_CARE;
+		list_del(&e->list);
 	} else {
 		e->name_state = NAME_NEEDED;
 		hci_inquiry_cache_update_resolve(hdev, e);
-- 
2.34.0.rc0.344.g81b53c2807-goog

[PATCH 3/3] Bluetooth: Limit duration of Remote Name Resolve

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

When doing remote name request, we cannot scan. In the normal case it's
OK since we can expect it to finish within a short amount of time.
However, there is a possibility to scan lots of devices that
(1) requires Remote Name Resolve
(2) is unresponsive to Remote Name Resolve
When this happens, we are stuck to do Remote Name Resolve until all is
done before continue scanning.

This patch adds a time limit to stop us spending too long on remote
name request.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
---

 include/net/bluetooth/hci_core.h | 3 +++
 net/bluetooth/hci_event.c        | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index eb08dd502f2a..941cfbb024d1 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -89,6 +89,7 @@ struct discovery_state {
 	u8			(*uuids)[16];
 	unsigned long		scan_start;
 	unsigned long		scan_duration;
+	unsigned long		name_resolve_timeout;
 };
 
 #define SUSPEND_NOTIFIER_TIMEOUT	msecs_to_jiffies(2000) /* 2 seconds */
@@ -1763,6 +1764,8 @@ void hci_mgmt_chan_unregister(struct hci_mgmt_chan *c);
 #define DISCOV_LE_FAST_ADV_INT_MIN	0x00A0	/* 100 msec */
 #define DISCOV_LE_FAST_ADV_INT_MAX	0x00F0	/* 150 msec */
 
+#define NAME_RESOLVE_DURATION		msecs_to_jiffies(10240)	/* msec */
+
 void mgmt_fill_version_info(void *ver);
 int mgmt_new_settings(struct hci_dev *hdev);
 void mgmt_index_added(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 2de3080659f9..6180ab0e8b8d 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2129,6 +2129,12 @@ static bool hci_resolve_next_name(struct hci_dev *hdev)
 	if (list_empty(&discov->resolve))
 		return false;
 
+	/* We should stop if we already spent too much time resolving names. */
+	if (time_after(jiffies, discov->name_resolve_timeout)) {
+		bt_dev_dbg(hdev, "Name resolve takes too long, stopping.");
+		return false;
+	}
+
 	e = hci_inquiry_cache_lookup_resolve(hdev, BDADDR_ANY, NAME_NEEDED);
 	if (!e)
 		return false;
@@ -2716,6 +2722,7 @@ static void hci_inquiry_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	if (e && hci_resolve_name(hdev, e) == 0) {
 		e->name_state = NAME_PENDING;
 		hci_discovery_set_state(hdev, DISCOVERY_RESOLVING);
+		discov->name_resolve_timeout = jiffies + NAME_RESOLVE_DURATION;
 	} else {
 		/* When BR/EDR inquiry is active and no LE scanning is in
 		 * progress, then change discovery state to indicate completion.
-- 
2.34.0.rc0.344.g81b53c2807-goog