2012-08-30 09:28:59

by Ganir, Chen

[permalink] [raw]
Subject: [PATCH] gatt: Delay D-Bus reply on char discovery

From: Chen Ganir <[email protected]>

Delay sending the D-Bus reply for the discover_characteristics
command. The D-Bus reply for characteristics is sent before all
the relevant characteristic information is gathered. This can
cause problems, when trying to get characteristic information too
soon. This patch moves the D-Bus reply to the end of the char
discovery process. Only after all descriptors are discovered and
read, the D-Bus reply is sent.
---
attrib/client.c | 163 +++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 116 insertions(+), 47 deletions(-)

diff --git a/attrib/client.c b/attrib/client.c
index bb6adf8..9b2103b 100644
--- a/attrib/client.c
+++ b/attrib/client.c
@@ -78,6 +78,11 @@ struct gatt_service {
struct query *query;
};

+struct characteristic_descriptor {
+ uint16_t handle;
+ bt_uuid_t uuid;
+};
+
struct characteristic {
struct gatt_service *gatt;
char *path;
@@ -90,6 +95,9 @@ struct characteristic {
struct format *format;
uint8_t *value;
size_t vlen;
+
+ GSList *descriptors;
+ uint16_t descriptor_count;
};

struct query_data {
@@ -116,6 +124,7 @@ static void characteristic_free(void *user_data)
g_free(chr->format);
g_free(chr->value);
g_free(chr->name);
+ g_slist_free_full(chr->descriptors, g_free);
g_free(chr);
}

@@ -263,6 +272,71 @@ static void update_watchers(gpointer data, gpointer user_data)
g_dbus_send_message(conn, msg);
}

+static DBusMessage *create_discover_char_reply(DBusMessage *msg, GSList *chars)
+{
+ DBusMessage *reply;
+ DBusMessageIter iter, array_iter;
+ GSList *l;
+
+ reply = dbus_message_new_method_return(msg);
+
+ dbus_message_iter_init_append(reply, &iter);
+
+ dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY,
+ DBUS_TYPE_OBJECT_PATH_AS_STRING, &array_iter);
+
+ for (l = chars; l; l = l->next) {
+ struct characteristic *chr = l->data;
+
+ dbus_message_iter_append_basic(&array_iter,
+ DBUS_TYPE_OBJECT_PATH, &chr->path);
+ }
+
+ dbus_message_iter_close_container(&iter, &array_iter);
+
+ return reply;
+}
+
+
+static void check_chr_discovery_complete(struct gatt_service *gatt)
+{
+ DBusMessage *reply;
+ GSList *l;
+
+ for (l = gatt->chars; l; l = l->next) {
+ struct characteristic *chr = l->data;
+
+ if (chr->descriptor_count == 0xFFFF)
+ return;
+
+ if (chr->descriptor_count > g_slist_length(chr->descriptors))
+ return;
+ }
+
+ reply = create_discover_char_reply(gatt->query->msg, gatt->chars);
+
+ dbus_message_unref(gatt->query->msg);
+ gatt->query->msg = NULL;
+
+ g_dbus_send_message(gatt->conn, reply);
+}
+
+static void add_descriptor(struct gatt_service *gatt,
+ struct characteristic *chr, uint16_t handle,
+ bt_uuid_t uuid)
+{
+ struct characteristic_descriptor *desc;
+
+ desc = g_new0(struct characteristic_descriptor, 1);
+
+ desc->handle = handle;
+ desc->uuid = uuid;
+
+ chr->descriptors = g_slist_append(chr->descriptors, desc);
+
+ check_chr_discovery_complete(gatt);
+}
+
static void events_handler(const uint8_t *pdu, uint16_t len,
gpointer user_data)
{
@@ -690,6 +764,7 @@ static void update_char_desc(guint8 status, const guint8 *pdu, guint16 len,
struct query_data *current = user_data;
struct gatt_service *gatt = current->gatt;
struct characteristic *chr = current->chr;
+ bt_uuid_t uuid;

if (status == 0) {

@@ -720,6 +795,9 @@ static void update_char_desc(guint8 status, const guint8 *pdu, guint16 len,
}
}

+ bt_uuid16_create(&uuid, GATT_CHARAC_USER_DESC_UUID);
+ add_descriptor(current->gatt, chr, current->handle, uuid);
+
query_list_remove(gatt, current);
g_free(current);
}
@@ -730,6 +808,7 @@ static void update_char_format(guint8 status, const guint8 *pdu, guint16 len,
struct query_data *current = user_data;
struct gatt_service *gatt = current->gatt;
struct characteristic *chr = current->chr;
+ bt_uuid_t uuid;

if (status != 0)
goto done;
@@ -746,6 +825,9 @@ static void update_char_format(guint8 status, const guint8 *pdu, guint16 len,
(void *) chr->format, sizeof(*chr->format));

done:
+ bt_uuid16_create(&uuid, GATT_CHARAC_FMT_UUID);
+ add_descriptor(current->gatt, chr, current->handle, uuid);
+
query_list_remove(gatt, current);
g_free(current);
}
@@ -789,24 +871,33 @@ static void descriptor_cb(guint8 status, const guint8 *pdu, guint16 plen,
{
struct query_data *current = user_data;
struct gatt_service *gatt = current->gatt;
+ struct characteristic *chr = current->chr;
struct att_data_list *list;
guint8 format;
int i;

- if (status != 0)
+ chr->descriptor_count = 0;
+
+ if (status != 0) {
+ check_chr_discovery_complete(gatt);
goto done;
+ }

DBG("Find Information Response received");

list = dec_find_info_resp(pdu, plen, &format);
- if (list == NULL)
+ if (list == NULL) {
+ check_chr_discovery_complete(gatt);
goto done;
+ }

+ chr->descriptor_count = list->num;
for (i = 0; i < list->num; i++) {
guint16 handle;
bt_uuid_t uuid;
uint8_t *info = list->data[i];
struct query_data *qfmt;
+ guint ret = 0;

handle = att_get_u16(info);

@@ -817,6 +908,7 @@ static void descriptor_cb(guint8 status, const guint8 *pdu, guint16 plen,
* format" descriptors are used, and both have 16-bit
* UUIDs. Therefore there is no need to support format
* 0x02 yet. */
+ add_descriptor(gatt, chr, current->handle, uuid);
continue;
}
qfmt = g_new0(struct query_data, 1);
@@ -826,14 +918,17 @@ static void descriptor_cb(guint8 status, const guint8 *pdu, guint16 plen,

if (uuid_desc16_cmp(&uuid, GATT_CHARAC_USER_DESC_UUID) == 0) {
query_list_append(gatt, qfmt);
- gatt_read_char(gatt->attrib, handle, 0, update_char_desc,
- qfmt);
+ ret = gatt_read_char(gatt->attrib, handle, 0,
+ update_char_desc, qfmt);
} else if (uuid_desc16_cmp(&uuid, GATT_CHARAC_FMT_UUID) == 0) {
query_list_append(gatt, qfmt);
- gatt_read_char(gatt->attrib, handle, 0,
+ ret = gatt_read_char(gatt->attrib, handle, 0,
update_char_format, qfmt);
} else
g_free(qfmt);
+
+ if (ret == 0)
+ add_descriptor(gatt, chr, current->handle, uuid);
}

att_data_list_free(list);
@@ -848,53 +943,31 @@ static void update_all_chars(gpointer data, gpointer user_data)
struct characteristic *chr = data;
struct gatt_service *gatt = user_data;

- qdesc = g_new0(struct query_data, 1);
- qdesc->gatt = gatt;
- qdesc->chr = chr;
-
- query_list_append(gatt, qdesc);
-
- gatt_find_info(gatt->attrib, chr->handle + 1, chr->end, descriptor_cb,
- qdesc);
-
qvalue = g_new0(struct query_data, 1);
qvalue->gatt = gatt;
qvalue->chr = chr;

+ g_slist_free_full(chr->descriptors, g_free);
+ chr->descriptors = NULL;
+ chr->descriptor_count = 0xFFFF;
+
query_list_append(gatt, qvalue);

gatt_read_char(gatt->attrib, chr->handle, 0, update_char_value, qvalue);
-}
-
-static DBusMessage *create_discover_char_reply(DBusMessage *msg, GSList *chars)
-{
- DBusMessage *reply;
- DBusMessageIter iter, array_iter;
- GSList *l;
-
- reply = dbus_message_new_method_return(msg);
-
- dbus_message_iter_init_append(reply, &iter);

- dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY,
- DBUS_TYPE_OBJECT_PATH_AS_STRING, &array_iter);
-
- for (l = chars; l; l = l->next) {
- struct characteristic *chr = l->data;
-
- dbus_message_iter_append_basic(&array_iter,
- DBUS_TYPE_OBJECT_PATH, &chr->path);
- }
+ qdesc = g_new0(struct query_data, 1);
+ qdesc->gatt = gatt;
+ qdesc->chr = chr;

- dbus_message_iter_close_container(&iter, &array_iter);
+ query_list_append(gatt, qdesc);

- return reply;
+ gatt_find_info(gatt->attrib, chr->handle + 1, chr->end, descriptor_cb,
+ qdesc);
}

static void char_discovered_cb(GSList *characteristics, guint8 status,
gpointer user_data)
{
- DBusMessage *reply;
struct query_data *current = user_data;
struct gatt_service *gatt = current->gatt;
struct gatt_primary *prim = gatt->prim;
@@ -905,10 +978,13 @@ static void char_discovered_cb(GSList *characteristics, guint8 status,

if (status != 0) {
const char *str = att_ecode2str(status);
+ DBusMessage *reply = btd_error_failed(gatt->query->msg, str);

DBG("Discover all characteristics failed: %s", str);
- reply = btd_error_failed(gatt->query->msg, str);
- goto fail;
+ dbus_message_unref(gatt->query->msg);
+ g_dbus_send_message(gatt->conn, reply);
+
+ goto done;
}

for (l = characteristics; l; l = l->next) {
@@ -943,16 +1019,9 @@ static void char_discovered_cb(GSList *characteristics, guint8 status,
gatt_get_address(gatt, &sba, &dba, &bdaddr_type);
store_characteristics(&sba, &dba, bdaddr_type, prim->range.start,
gatt->chars);
-
g_slist_foreach(gatt->chars, update_all_chars, gatt);

- reply = create_discover_char_reply(gatt->query->msg, gatt->chars);
-
-fail:
- dbus_message_unref(gatt->query->msg);
- gatt->query->msg = NULL;
-
- g_dbus_send_message(gatt->conn, reply);
+done:
query_list_remove(gatt, current);
g_free(current);
}
--
1.7.9.5