[Bluez PATCH v2 1/3] Listen and process remote name resolving failure

[Bluez PATCH v2 1/3] Listen and process remote name resolving failure

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

When Remote Name Resolve ends with failure, record this occurrence and
prevent remote name resolving for the same device for some time.
Increase the time duration for subsequent failures.
---
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 kernel space change.

Changes in v2:
* Stay silent instead of sending MGMT_OP_CONFIRM_NAME with DONT_CARE flag.

 lib/mgmt.h    |  1 +
 src/adapter.c | 15 +++++++++++++--
 src/device.c  | 23 +++++++++++++++++++++++
 src/device.h  |  2 ++
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/lib/mgmt.h b/lib/mgmt.h
index 0d1678f01d..468d31cafb 100644
--- a/lib/mgmt.h
+++ b/lib/mgmt.h
@@ -856,6 +856,7 @@ struct mgmt_ev_auth_failed {
 #define MGMT_DEV_FOUND_CONFIRM_NAME	0x01
 #define MGMT_DEV_FOUND_LEGACY_PAIRING	0x02
 #define MGMT_DEV_FOUND_NOT_CONNECTABLE	0x04
+#define MGMT_DEV_FOUND_NAME_RESOLVE_FAILED 0x10
 
 #define MGMT_EV_DEVICE_FOUND		0x0012
 struct mgmt_ev_device_found {
diff --git a/src/adapter.c b/src/adapter.c
index d0d38621b8..0003bc5d42 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -6989,6 +6989,7 @@ static void update_found_devices(struct btd_adapter *adapter,
 					uint8_t bdaddr_type, int8_t rssi,
 					bool confirm, bool legacy,
 					bool not_connectable,
+					bool name_resolve_failed,
 					const uint8_t *data, uint8_t data_len)
 {
 	struct btd_device *dev;
@@ -7081,6 +7082,9 @@ static void update_found_devices(struct btd_adapter *adapter,
 
 	device_set_legacy(dev, legacy);
 
+	if (name_resolve_failed)
+		device_name_resolve_fail(dev);
+
 	if (adapter->filtered_discovery)
 		device_set_rssi_with_delta(dev, rssi, 0);
 	else
@@ -7151,7 +7155,10 @@ static void update_found_devices(struct btd_adapter *adapter,
 	if (g_slist_find(adapter->discovery_found, dev))
 		return;
 
-	if (confirm)
+	/* If name is unknown but it's not allowed to resolve, don't send
+	 * MGMT_OP_CONFIRM_NAME.
+	 */
+	if (confirm && (name_known || device_name_resolve_allowed(dev)))
 		confirm_name(adapter, bdaddr, bdaddr_type, name_known);
 
 	adapter->discovery_found = g_slist_prepend(adapter->discovery_found,
@@ -7201,6 +7208,8 @@ static void device_found_callback(uint16_t index, uint16_t length,
 	uint32_t flags;
 	bool confirm_name;
 	bool legacy;
+	bool not_connectable;
+	bool name_resolve_failed;
 	char addr[18];
 
 	if (length < sizeof(*ev)) {
@@ -7230,10 +7239,12 @@ static void device_found_callback(uint16_t index, uint16_t length,
 
 	confirm_name = (flags & MGMT_DEV_FOUND_CONFIRM_NAME);
 	legacy = (flags & MGMT_DEV_FOUND_LEGACY_PAIRING);
+	not_connectable = (flags & MGMT_DEV_FOUND_NOT_CONNECTABLE);
+	name_resolve_failed = (flags & MGMT_DEV_FOUND_NAME_RESOLVE_FAILED);
 
 	update_found_devices(adapter, &ev->addr.bdaddr, ev->addr.type,
 					ev->rssi, confirm_name, legacy,
-					flags & MGMT_DEV_FOUND_NOT_CONNECTABLE,
+					not_connectable, name_resolve_failed,
 					eir, eir_len);
 }
 
diff --git a/src/device.c b/src/device.c
index fdc2d50a47..699faeba3b 100644
--- a/src/device.c
+++ b/src/device.c
@@ -79,6 +79,8 @@
 #define GATT_INCLUDE_UUID_STR "2802"
 #define GATT_CHARAC_UUID_STR "2803"
 
+#define NAME_RESOLVE_RETRY_DELAY	120 /* seconds */
+
 static DBusConnection *dbus_conn = NULL;
 static unsigned service_state_cb_id;
 
@@ -272,6 +274,9 @@ struct btd_device {
 
 	GIOChannel	*att_io;
 	guint		store_id;
+
+	time_t		name_resolve_earliest_allow_time;
+	uint8_t		name_resolve_fail_count;
 };
 
 static const uint16_t uuid_list[] = {
@@ -4361,6 +4366,24 @@ bool device_name_known(struct btd_device *device)
 	return device->name[0] != '\0';
 }
 
+bool device_name_resolve_allowed(struct btd_device *device)
+{
+	return time(NULL) >= device->name_resolve_earliest_allow_time;
+}
+
+void device_name_resolve_fail(struct btd_device *device)
+{
+	if (!device)
+		return;
+
+	/* Punish this device by not allowing name resolve for some time.
+	 * increase punishment time for subsequent failures.
+	 */
+	device->name_resolve_fail_count++;
+	device->name_resolve_earliest_allow_time = time(NULL) +
+		NAME_RESOLVE_RETRY_DELAY * device->name_resolve_fail_count;
+}
+
 void device_set_class(struct btd_device *device, uint32_t class)
 {
 	if (device->class == class)
diff --git a/src/device.h b/src/device.h
index 5f615cb4b6..76d79855f8 100644
--- a/src/device.h
+++ b/src/device.h
@@ -25,6 +25,8 @@ void btd_device_device_set_name(struct btd_device *device, const char *name);
 void device_store_cached_name(struct btd_device *dev, const char *name);
 void device_get_name(struct btd_device *device, char *name, size_t len);
 bool device_name_known(struct btd_device *device);
+bool device_name_resolve_allowed(struct btd_device *device);
+void device_name_resolve_fail(struct btd_device *device);
 void device_set_class(struct btd_device *device, uint32_t class);
 void device_update_addr(struct btd_device *device, const bdaddr_t *bdaddr,
 							uint8_t bdaddr_type);
-- 
2.34.0.rc1.387.gb447b232ab-goog

[Bluez PATCH v2 2/3] device: Save remote name request attempts into cache file

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

Since a peer device is potentially removed if not discovered for more
than 30 seconds, we would lost the remote name request activity when
the device is rediscovered. This could end up with a remote name
request much sooner than we intend it to be.

Therefore, put the RNR record into a cache file, so we can recover it
when the peer device is rediscovered.

Reviewed-by: Sonny Sasaka <sonnysasaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
---

(no changes since v1)

 src/device.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 94 insertions(+), 2 deletions(-)

diff --git a/src/device.c b/src/device.c
index 699faeba3b..fa6e3abc37 100644
--- a/src/device.c
+++ b/src/device.c
@@ -568,6 +568,63 @@ void device_store_cached_name(struct btd_device *dev, const char *name)
 	g_key_file_free(key_file);
 }
 
+static void device_store_cached_name_resolve_attempts(struct btd_device *dev)
+{
+	char filename[PATH_MAX];
+	char d_addr[18];
+	GKeyFile *key_file;
+	GError *gerr = NULL;
+	char *data;
+	char *data_old;
+	gsize length = 0;
+	gsize length_old = 0;
+	uint64_t earliest_allowed;
+	unsigned int num_failures;
+
+	if (device_address_is_private(dev)) {
+		DBG("Can't store name resolve for private addressed device %s",
+								dev->path);
+		return;
+	}
+
+	ba2str(&dev->bdaddr, d_addr);
+	snprintf(filename, PATH_MAX, STORAGEDIR "/%s/cache/%s",
+			btd_adapter_get_storage_dir(dev->adapter), d_addr);
+	create_file(filename, 0600);
+
+	key_file = g_key_file_new();
+	if (!g_key_file_load_from_file(key_file, filename, 0, &gerr)) {
+		error("Unable to load key file from %s: (%s)", filename,
+								gerr->message);
+		g_error_free(gerr);
+	}
+
+	earliest_allowed = (uint64_t) dev->name_resolve_earliest_allow_time;
+	num_failures = dev->name_resolve_fail_count;
+
+	data_old = g_key_file_to_data(key_file, &length_old, NULL);
+
+	g_key_file_set_uint64(key_file, "NameResolve", "EarliestAllowed",
+							earliest_allowed);
+	g_key_file_set_integer(key_file, "NameResolve", "NumFailures",
+							num_failures);
+
+	data = g_key_file_to_data(key_file, &length, NULL);
+
+	if ((length != length_old) || (memcmp(data, data_old, length))) {
+		if (!g_file_set_contents(filename, data, length, &gerr)) {
+			error("Unable set contents for %s: (%s)", filename,
+								gerr->message);
+			g_error_free(gerr);
+		}
+	}
+
+	g_free(data);
+	g_free(data_old);
+
+	g_key_file_free(key_file);
+}
+
 static void browse_request_free(struct browse_req *req)
 {
 	struct btd_device *device = req->device;
@@ -3277,6 +3334,36 @@ failed:
 	return str;
 }
 
+static void load_cached_name_resolve_attempts(struct btd_device *device,
+					const char *local, const char *peer)
+{
+	char filename[PATH_MAX];
+	GKeyFile *key_file;
+	uint64_t earliest_allowed;
+	unsigned int num_failures;
+
+	if (device_address_is_private(device))
+		return;
+
+	snprintf(filename, PATH_MAX, STORAGEDIR "/%s/cache/%s", local, peer);
+
+	key_file = g_key_file_new();
+
+	if (!g_key_file_load_from_file(key_file, filename, 0, NULL))
+		goto failed;
+
+	earliest_allowed = g_key_file_get_uint64(key_file, "NameResolve",
+						"EarliestAllowed", NULL);
+	num_failures = g_key_file_get_uint64(key_file, "NameResolve",
+						"NumFailures", NULL);
+
+	device->name_resolve_earliest_allow_time = earliest_allowed;
+	device->name_resolve_fail_count = (uint8_t) num_failures;
+
+failed:
+	g_key_file_free(key_file);
+}
+
 static struct csrk_info *load_csrk(GKeyFile *key_file, const char *group)
 {
 	struct csrk_info *csrk;
@@ -4284,6 +4371,7 @@ struct btd_device *device_create(struct btd_adapter *adapter,
 	struct btd_device *device;
 	char dst[18];
 	char *str;
+	const char *storage_dir;
 
 	ba2str(bdaddr, dst);
 	DBG("dst %s", dst);
@@ -4299,13 +4387,15 @@ struct btd_device *device_create(struct btd_adapter *adapter,
 	else
 		device->le = true;
 
-	str = load_cached_name(device, btd_adapter_get_storage_dir(adapter),
-									dst);
+	storage_dir = btd_adapter_get_storage_dir(adapter);
+	str = load_cached_name(device, storage_dir, dst);
 	if (str) {
 		strcpy(device->name, str);
 		g_free(str);
 	}
 
+	load_cached_name_resolve_attempts(device, storage_dir, dst);
+
 	return device;
 }
 
@@ -4382,6 +4472,8 @@ void device_name_resolve_fail(struct btd_device *device)
 	device->name_resolve_fail_count++;
 	device->name_resolve_earliest_allow_time = time(NULL) +
 		NAME_RESOLVE_RETRY_DELAY * device->name_resolve_fail_count;
+
+	device_store_cached_name_resolve_attempts(device);
 }
 
 void device_set_class(struct btd_device *device, uint32_t class)
-- 
2.34.0.rc1.387.gb447b232ab-goog

[Bluez PATCH v2 3/3] doc: Add Name Resolve Fail flag in device found event

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

Userspace should use this new flag to decide whether to do the remote
name resolving or not, by sending Confirm Name MGMT command and set
the appropriate flag.
---

Changes in v2:
* Update docs to reflect not sending DONT_CARE flag behavior.

 doc/mgmt-api.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/doc/mgmt-api.txt b/doc/mgmt-api.txt
index 97d33e30a1..340d8ffa85 100644
--- a/doc/mgmt-api.txt
+++ b/doc/mgmt-api.txt
@@ -4089,6 +4089,7 @@ Device Connected Event
 		1	Legacy Pairing
 		2	Reserved (not in use)
 		3	Initiated Connection
+		4	Reserved (not in use)
 
 
 Device Disconnected Event
@@ -4263,6 +4264,7 @@ Device Found Event
 		1	Legacy Pairing
 		2	Not Connectable
 		3	Reserved (not in use)
+		4	Name Resolve Failed
 
 	For the RSSI field a value of 127 indicates that the RSSI is
 	not available. That can happen with Bluetooth 1.1 and earlier
@@ -4285,6 +4287,11 @@ Device Found Event
 	accept any connections. This can be indicated by Low Energy
 	devices that are in broadcaster role.
 
+	The Name Resolve Failed flag indicates that name resolving
+	procedure has ended with failure for this device. The user space
+	should use this information to determine when is a good time to
+	retry the name resolving procedure.
+
 
 Discovering Event
 =================
-- 
2.34.0.rc1.387.gb447b232ab-goog

RE: [Bluez,v2,1/3] Listen and process remote name resolving failure

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1223 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=579995

---Test result---

Test Summary:
CheckPatch                    PASS      1.58 seconds
GitLint                       FAIL      0.86 seconds
Prep - Setup ELL              PASS      46.44 seconds
Build - Prep                  PASS      0.25 seconds
Build - Configure             PASS      8.36 seconds
Build - Make                  PASS      205.20 seconds
Make Check                    PASS      8.69 seconds
Make Distcheck                PASS      244.13 seconds
Build w/ext ELL - Configure   PASS      8.57 seconds
Build w/ext ELL - Make        PASS      191.15 seconds

Details
##############################
Test: GitLint - FAIL
Desc: Run gitlint with rule in .gitlint
Output:
[Bluez,v2,1/3] Listen and process remote name resolving failure
12: B1 Line exceeds max length (121>80): "https://patchwork.kernel.org/project/bluetooth/patch/20211028191805.1.I35b7f3a496f834de6b43a32f94b6160cb1467c94@changeid/"




---
Regards,
Linux Bluetooth

Re: [Bluez PATCH v2 1/3] Listen and process remote name resolving failure

[Marcel Holtmann]

Hi Archie,

> When Remote Name Resolve ends with failure, record this occurrence and
> prevent remote name resolving for the same device for some time.
> Increase the time duration for subsequent failures.
> ---
> 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 kernel space change.
> 
> Changes in v2:
> * Stay silent instead of sending MGMT_OP_CONFIRM_NAME with DONT_CARE flag.
> 
> lib/mgmt.h    |  1 +
> src/adapter.c | 15 +++++++++++++--
> src/device.c  | 23 +++++++++++++++++++++++
> src/device.h  |  2 ++
> 4 files changed, 39 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/mgmt.h b/lib/mgmt.h
> index 0d1678f01d..468d31cafb 100644
> --- a/lib/mgmt.h
> +++ b/lib/mgmt.h
> @@ -856,6 +856,7 @@ struct mgmt_ev_auth_failed {
> #define MGMT_DEV_FOUND_CONFIRM_NAME	0x01
> #define MGMT_DEV_FOUND_LEGACY_PAIRING	0x02
> #define MGMT_DEV_FOUND_NOT_CONNECTABLE	0x04
> +#define MGMT_DEV_FOUND_NAME_RESOLVE_FAILED 0x10

NAME_REQUEST_FAILED please.

And you might want to indent the rest of the variables and provide this as an independent patch.

Regards

Marcel