Hi Luiz,
> On Mon, Nov 10, 2014 at 6:02 AM, Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote:
> Hi Arman,
>
> On Fri, Nov 7, 2014 at 10:41 PM, Arman Uguray <armansito@xxxxxxxxxxxx> wrote:
>> This patch add support for handling ATT "Prepare Write" requests for the
>> server role.
>> ---
>> src/shared/gatt-server.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++
>> src/shared/gatt-server.h | 3 +
>> 2 files changed, 145 insertions(+)
>>
>> diff --git a/src/shared/gatt-server.c b/src/shared/gatt-server.c
>> index e77acce..48a55e7 100644
>> --- a/src/shared/gatt-server.c
>> +++ b/src/shared/gatt-server.c
>> @@ -40,6 +40,8 @@
>> #define MIN(a, b) ((a) < (b) ? (a) : (b))
>> #endif
>>
>> +#define DEFAULT_MAX_PREP_QUEUE_LEN 5
>> +
>> struct async_read_op {
>> struct bt_gatt_server *server;
>> uint8_t opcode;
>> @@ -55,6 +57,22 @@ struct async_write_op {
>> uint8_t opcode;
>> };
>>
>> +struct prep_write_data {
>> + struct bt_gatt_server *server;
>> + uint8_t *value;
>> + uint16_t handle;
>> + uint16_t offset;
>> + uint16_t length;
>> +};
>> +
>> +static void prep_write_data_destroy(void *user_data)
>> +{
>> + struct prep_write_data *data = user_data;
>> +
>> + free(data->value);
>> + free(data);
>> +}
>> +
>> struct bt_gatt_server {
>> struct gatt_db *db;
>> struct bt_att *att;
>> @@ -69,6 +87,10 @@ struct bt_gatt_server {
>> unsigned int write_cmd_id;
>> unsigned int read_id;
>> unsigned int read_blob_id;
>> + unsigned int prep_write_id;
>> +
>> + struct queue *prep_queue;
>> + unsigned int max_prep_queue_len;
>>
>> struct async_read_op *pending_read_op;
>> struct async_write_op *pending_write_op;
>> @@ -91,6 +113,7 @@ static void bt_gatt_server_free(struct bt_gatt_server *server)
>> bt_att_unregister(server->att, server->write_cmd_id);
>> bt_att_unregister(server->att, server->read_id);
>> bt_att_unregister(server->att, server->read_blob_id);
>> + bt_att_unregister(server->att, server->prep_write_id);
>>
>> if (server->pending_read_op)
>> server->pending_read_op->server = NULL;
>> @@ -98,6 +121,8 @@ static void bt_gatt_server_free(struct bt_gatt_server *server)
>> if (server->pending_write_op)
>> server->pending_write_op->server = NULL;
>>
>> + queue_destroy(server->prep_queue, prep_write_data_destroy);
>> +
>> bt_att_unref(server->att);
>> free(server);
>> }
>> @@ -922,6 +947,98 @@ static void read_blob_cb(uint8_t opcode, const void *pdu,
>> handle_read_req(server, opcode, handle, offset);
>> }
>>
>> +static void prep_write_cb(uint8_t opcode, const void *pdu,
>> + uint16_t length, void *user_data)
>> +{
>> + struct bt_gatt_server *server = user_data;
>> + struct prep_write_data *prep_data = NULL;
>> + uint16_t handle = 0;
>> + uint16_t offset;
>> + struct gatt_db_attribute *attr;
>> + uint8_t rsp_opcode;
>> + uint8_t rsp_pdu[MAX(4, length)];
>> + uint16_t rsp_len;
>> + uint8_t ecode;
>> + uint32_t perm;
>> +
>> + if (length < 4) {
>> + ecode = BT_ATT_ERROR_INVALID_PDU;
>> + goto error;
>> + }
>> +
>> + if (queue_length(server->prep_queue) >= server->max_prep_queue_len) {
>> + ecode = BT_ATT_ERROR_PREPARE_QUEUE_FULL;
>> + goto error;
>> + }
>> +
>> + handle = get_le16(pdu);
>> + offset = get_le16(pdu + 2);
>> +
>> + attr = gatt_db_get_attribute(server->db, handle);
>> + if (!attr) {
>> + ecode = BT_ATT_ERROR_INVALID_HANDLE;
>> + goto error;
>> + }
>> +
>> + if (!gatt_db_attribute_get_permissions(attr, &perm)) {
>> + ecode = BT_ATT_ERROR_INVALID_HANDLE;
>> + goto error;
>> + }
>> +
>> + /*
>> + * TODO: The "Prepare Write" request requires security permission checks
>> + * to be performed before the write is executed. I.e., we can't leave
>> + * the permission check to the upper layer since we can't call
>> + * gatt_db_write until the entire queue is atomically processed during
>> + * an "Execute Write" request. Figure out how to make this check here.
>> + */
>> + if (!(perm & BT_ATT_PERM_WRITE)) {
>> + ecode = BT_ATT_ERROR_WRITE_NOT_PERMITTED;
>> + goto error;
>> + }
>> +
>> + prep_data = new0(struct prep_write_data, 1);
>> + if (!prep_data) {
>> + ecode = BT_ATT_ERROR_INSUFFICIENT_RESOURCES;
>> + goto error;
>> + }
>> +
>> + prep_data->length = length - 4;
>> + if (prep_data->length) {
>> + prep_data->value = malloc(prep_data->length);
>> + if (!prep_data->value) {
>> + ecode = BT_ATT_ERROR_INSUFFICIENT_RESOURCES;
>> + goto error;
>> + }
>> + }
>> +
>> + prep_data->server = server;
>> + prep_data->handle = handle;
>> + prep_data->offset = offset;
>> + memcpy(prep_data->value, pdu + 4, prep_data->length);
>> +
>> + queue_push_tail(server->prep_queue, prep_data);
>> +
>> + /* Create the response */
>> + rsp_len = length;
>> + rsp_opcode = BT_ATT_OP_PREP_WRITE_RSP;
>> + memcpy(rsp_pdu, pdu, rsp_len);
>> +
>> + goto done;
>> +
>> +error:
>> + if (prep_data)
>> + prep_write_data_destroy(prep_data);
>> +
>> + rsp_opcode = BT_ATT_OP_ERROR_RSP;
>> + rsp_len = 4;
>> + encode_error_rsp(opcode, handle, ecode, rsp_pdu);
>> +
>> +done:
>> + bt_att_send(server->att, rsp_opcode, rsp_pdu, rsp_len, NULL, NULL,
>> + NULL);
>> +}
>> +
>> static void exchange_mtu_cb(uint8_t opcode, const void *pdu,
>> uint16_t length, void *user_data)
>> {
>> @@ -1015,6 +1132,13 @@ static bool gatt_server_register_att_handlers(struct bt_gatt_server *server)
>> if (!server->read_blob_id)
>> return false;
>>
>> + /* Prepare Write Request */
>> + server->prep_write_id = bt_att_register(server->att,
>> + BT_ATT_OP_PREP_WRITE_REQ,
>> + prep_write_cb, server, NULL);
>> + if (!server->prep_write_id)
>> + return false;
>> +
>> return true;
>> }
>>
>> @@ -1033,6 +1157,13 @@ struct bt_gatt_server *bt_gatt_server_new(struct gatt_db *db,
>> server->db = db;
>> server->att = bt_att_ref(att);
>> server->mtu = MAX(mtu, BT_ATT_DEFAULT_LE_MTU);
>> + server->max_prep_queue_len = DEFAULT_MAX_PREP_QUEUE_LEN;
>> +
>> + server->prep_queue = queue_new();
>> + if (!server->prep_queue) {
>> + bt_gatt_server_free(server);
>> + return NULL;
>> + }
>>
>> if (!gatt_server_register_att_handlers(server)) {
>> bt_gatt_server_free(server);
>> @@ -1078,6 +1209,17 @@ bool bt_gatt_server_set_debug(struct bt_gatt_server *server,
>> return true;
>> }
>>
>> +bool bt_gatt_server_set_max_prep_queue_length(struct bt_gatt_server *server,
>> + unsigned int length)
>> +{
>> + if (!server || !length)
>> + return false;
>> +
>> + server->max_prep_queue_len = length;
>> +
>> + return true;
>> +}
>> +
>> bool bt_gatt_server_send_notification(struct bt_gatt_server *server,
>> uint16_t handle, const uint8_t *value,
>> uint16_t length)
>> diff --git a/src/shared/gatt-server.h b/src/shared/gatt-server.h
>> index 0e480e1..a95613c 100644
>> --- a/src/shared/gatt-server.h
>> +++ b/src/shared/gatt-server.h
>> @@ -40,6 +40,9 @@ bool bt_gatt_server_set_debug(struct bt_gatt_server *server,
>> void *user_data,
>> bt_gatt_server_destroy_func_t destroy);
>>
>> +bool bt_gatt_server_set_max_prep_queue_length(struct bt_gatt_server *server,
>> + unsigned int length);
>
> Perhaps we should leave this API for later, Im not really sure if this
> will be ever used except perhaps for the TS in that case perhaps we
> should find a shorter name.
>
In our case would it even make sense to have a maximum queue length? I
only added because there is an error for it and an application with
memory constraints may want to limit the size perhaps? Anyway, for now
I can set this to something arbitrary for v2.
>> bool bt_gatt_server_send_notification(struct bt_gatt_server *server,
>> uint16_t handle, const uint8_t *value,
>> uint16_t length);
>> --
>> 2.1.0.rc2.206.gedb03e5
>>
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>
>
>
> --
> Luiz Augusto von Dentz
Cheers,
Arman
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