Hi Luiz,
On Fri, Oct 24, 2014 at 2:25 AM, Luiz Augusto von Dentz
<luiz.dentz@xxxxxxxxx> wrote:
> Hi Arman,
>
> On Tue, Oct 21, 2014 at 12:00 AM, Arman Uguray <armansito@xxxxxxxxxxxx> wrote:
>> This patch implements the ATT protocol "Read By Type" request for
>> shared/gatt-server. Logic is implemented that allows asynchronous
>> reading of non-standard attribute values via the registered read and
>> read completion callbacks.
>> ---
>> src/shared/gatt-server.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++-
>> 1 file changed, 270 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/shared/gatt-server.c b/src/shared/gatt-server.c
>> index 3233b21..6c5ea2b 100644
>> --- a/src/shared/gatt-server.c
>> +++ b/src/shared/gatt-server.c
>> @@ -38,6 +38,16 @@
>> #define MIN(a, b) ((a) < (b) ? (a) : (b))
>> #endif
>>
>> +struct async_read_op {
>> + struct bt_gatt_server *server;
>> + uint8_t opcode;
>> + bool done;
>> + uint8_t *pdu;
>> + size_t pdu_len;
>> + int value_len;
>> + struct queue *db_data;
>> +};
>> +
>> struct bt_gatt_server {
>> struct gatt_db *db;
>> struct bt_att *att;
>> @@ -46,6 +56,9 @@ struct bt_gatt_server {
>>
>> unsigned int mtu_id;
>> unsigned int read_by_grp_type_id;
>> + unsigned int read_by_type_id;
>> +
>> + struct async_read_op *pending_read_op;
>>
>> bt_gatt_server_debug_func_t debug_callback;
>> bt_gatt_server_destroy_func_t debug_destroy;
>> @@ -59,8 +72,12 @@ static void bt_gatt_server_free(struct bt_gatt_server *server)
>>
>> bt_att_unregister(server->att, server->mtu_id);
>> bt_att_unregister(server->att, server->read_by_grp_type_id);
>> + bt_att_unregister(server->att, server->read_by_type_id);
>> bt_att_unref(server->att);
>>
>> + if (server->pending_read_op)
>> + server->pending_read_op->server = NULL;
>> +
>> free(server);
>> }
>>
>> @@ -124,21 +141,21 @@ static bool encode_read_by_grp_type_rsp(struct gatt_db *db, struct queue *q,
>> * value is seen.
>> */
>> if (iter == 0) {
>> - data_val_len = value_len;
>> + data_val_len = MIN(MIN(mtu - 6, 251), value_len);
>> pdu[0] = data_val_len + 4;
>> iter++;
>> } else if (value_len != data_val_len)
>> break;
>>
>> /* Stop if this unit would surpass the MTU */
>> - if (iter + data_val_len + 4 > mtu)
>> + if (iter + data_val_len + 4 > mtu - 1)
>> break;
>>
>> end_handle = gatt_db_get_end_handle(db, start_handle);
>>
>> put_le16(start_handle, pdu + iter);
>> put_le16(end_handle, pdu + iter + 2);
>> - memcpy(pdu + iter + 4, value, value_len);
>> + memcpy(pdu + iter + 4, value, data_val_len);
>>
>> iter += data_val_len + 4;
>> }
>> @@ -235,6 +252,248 @@ done:
>> NULL, NULL, NULL);
>> }
>>
>> +static void async_read_op_destroy(struct async_read_op *op)
>> +{
>> + if (op->server)
>> + op->server->pending_read_op = NULL;
>> +
>> + queue_destroy(op->db_data, NULL);
>> + free(op->pdu);
>> + free(op);
>> +}
>> +
>> +static void process_read_by_type(struct async_read_op *op);
>> +
>> +static void read_by_type_read_complete_cb(uint16_t handle, uint16_t att_ecode,
>> + const uint8_t *value, size_t len,
>> + void *complete_data)
>> +{
>> + struct async_read_op *op = complete_data;
>> + struct bt_gatt_server *server = op->server;
>> + uint16_t mtu;
>> +
>> + if (!server) {
>> + async_read_op_destroy(op);
>> + return;
>> + }
>> +
>> + mtu = bt_att_get_mtu(server->att);
>> +
>> + /* Terminate the operation if there was an error */
>> + if (att_ecode) {
>> + uint8_t pdu[4];
>> +
>> + encode_error_rsp(BT_ATT_OP_READ_BY_TYPE_REQ, handle, att_ecode,
>> + pdu);
>> + bt_att_send(server->att, BT_ATT_OP_ERROR_RSP, pdu, 4, NULL,
>> + NULL, NULL);
>> + async_read_op_destroy(op);
>> + return;
>> + }
>> +
>> + if (op->pdu_len == 0) {
>> + op->value_len = MIN(MIN(mtu - 4, 253), len);
>> + op->pdu[0] = op->value_len + 2;
>> + op->pdu_len++;
>> + } else if (len != op->value_len) {
>> + op->done = true;
>> + goto done;
>> + }
>> +
>> + /* Stop if this would surpass the MTU */
>> + if (op->pdu_len + op->value_len + 2 > mtu - 1) {
>> + op->done = true;
>> + goto done;
>> + }
>> +
>> + /* Encode the current value */
>> + put_le16(handle, op->pdu + op->pdu_len);
>> + memcpy(op->pdu + op->pdu_len + 2, value, op->value_len);
>> +
>> + op->pdu_len += op->value_len + 2;
>> +
>> + if (op->pdu_len == mtu - 1)
>> + op->done = true;
>
> The code above is duplicated and it is actually causing some warnings
> comparing unsigned with signed (usually cause by '-' operation) which
> I started fixing myself but stop once I realize this was the result of
> gatt_db_read having 2 modes to read, sync and async, which I don't
> think is a good idea.
>
Yes, please see my response to your other comment in this patch set.
>> +done:
>> + process_read_by_type(op);
>> +}
>> +
>> +static void process_read_by_type(struct async_read_op *op)
>> +{
>> + struct bt_gatt_server *server = op->server;
>> + uint16_t mtu = bt_att_get_mtu(server->att);
>> + uint8_t rsp_opcode;
>> + uint8_t rsp_len;
>> + uint8_t ecode;
>> + uint16_t ehandle;
>> + uint16_t start_handle;
>> + uint8_t *value;
>> + int value_len;
>> + uint32_t perm;
>> +
>> + if (op->done) {
>> + rsp_opcode = BT_ATT_OP_READ_BY_TYPE_RSP;
>> + rsp_len = op->pdu_len;
>> + goto done;
>> + }
>> +
>> + while (queue_peek_head(op->db_data)) {
>> + start_handle = PTR_TO_UINT(queue_pop_head(op->db_data));
>> + value = NULL;
>> + value_len = 0;
>> +
>> + if (!gatt_db_get_attribute_permissions(server->db, start_handle,
>> + &perm)) {
>> + ecode = BT_ATT_ERROR_UNLIKELY;
>> + goto error;
>> + }
>> +
>> + /*
>> + * Check for the READ access permission. Encryption,
>> + * authentication, and authorization permissions need to be
>> + * checked by the read handler, since bt_att is agnostic to
>> + * connection type and doesn't have security information on it.
>> + */
>> + if (perm && !(perm & BT_ATT_PERM_READ)) {
>> + ecode = BT_ATT_ERROR_READ_NOT_PERMITTED;
>> + goto error;
>> + }
>
> I would suggest moving this check to gatt_db_read which should return
> -EPERM or the actual code if it is too hard to have errno mapping for
> each error code.
>
gatt_db currently has this nice property that the permissions field is
just a uint32_t. This means that while shared/gatt-server can use the
new permission macros I added to shared/att-types, the android code
can still use the Android platform definitions. Of course, once
android starts using shared/gatt-server it'll have to use the new
macros but for now we can have gatt-db support both types by keeping
the permission checks outside of gatt-db and this would make the whole
transition easier. Makes sense?
>> + if (!gatt_db_read(server->db, start_handle, 0, op->opcode, NULL,
>> + &value, &value_len,
>> + read_by_type_read_complete_cb, op)) {
>> + ecode = BT_ATT_ERROR_UNLIKELY;
>> + goto error;
>> + }
>> +
>> + /* The read has been deferred to the upper layer if |value_len|
>> + * is less than 0.
>> + */
>> + if (value_len < 0)
>> + return;
>> +
>> + if (op->pdu_len == 0) {
>> + op->value_len = MIN(MIN(mtu - 4, 253), value_len);
>> + op->pdu[0] = op->value_len + 2;
>> + op->pdu_len++;
>> + } else if (value_len != op->value_len)
>> + break;
>> +
>> + /* Stop if this would surpass the MTU */
>> + if (op->pdu_len + op->value_len + 2 > mtu - 1)
>> + break;
>> +
>> + /* Encode the current value */
>> + put_le16(start_handle, op->pdu + op->pdu_len);
>> + memcpy(op->pdu + op->pdu_len + 2, value, op->value_len);
>> +
>> + op->pdu_len += op->value_len + 2;
>> +
>> + if (op->pdu_len == mtu - 1)
>> + break;
>> + }
>> +
>> + rsp_opcode = BT_ATT_OP_READ_BY_TYPE_RSP;
>> + rsp_len = op->pdu_len;
>> +
>> + goto done;
>> +
>> +error:
>> + rsp_opcode = BT_ATT_OP_ERROR_RSP;
>> + rsp_len = 4;
>> + encode_error_rsp(BT_ATT_OP_READ_BY_TYPE_REQ, ehandle, ecode, op->pdu);
>> +
>> +done:
>> + bt_att_send(server->att, rsp_opcode, op->pdu, rsp_len, NULL,
>> + NULL, NULL);
>> + async_read_op_destroy(op);
>> +}
>> +
>> +static void read_by_type_cb(uint8_t opcode, const void *pdu,
>> + uint16_t length, void *user_data)
>> +{
>> + struct bt_gatt_server *server = user_data;
>> + uint16_t start, end;
>> + bt_uuid_t type;
>> + uint8_t rsp_pdu[4];
>> + uint16_t ehandle = 0;
>> + uint8_t ecode;
>> + struct queue *q = NULL;
>> + struct async_read_op *op;
>> +
>> + if (length != 6 && length != 20) {
>> + ecode = BT_ATT_ERROR_INVALID_PDU;
>> + goto error;
>> + }
>> +
>> + q = queue_new();
>> + if (!q) {
>> + ecode = BT_ATT_ERROR_INSUFFICIENT_RESOURCES;
>> + goto error;
>> + }
>> +
>> + start = get_le16(pdu);
>> + end = get_le16(pdu + 2);
>> + get_uuid_le(pdu + 4, length - 4, &type);
>> +
>> + util_debug(server->debug_callback, server->debug_data,
>> + "Read By Type - start: 0x%04x end: 0x%04x",
>> + start, end);
>> +
>> + if (!start || !end) {
>> + ecode = BT_ATT_ERROR_INVALID_HANDLE;
>> + goto error;
>> + }
>> +
>> + ehandle = start;
>> +
>> + if (start > end) {
>> + ecode = BT_ATT_ERROR_INVALID_HANDLE;
>> + goto error;
>> + }
>> +
>> + gatt_db_read_by_type(server->db, start, end, type, q);
>> +
>> + if (queue_isempty(q)) {
>> + ecode = BT_ATT_ERROR_ATTRIBUTE_NOT_FOUND;
>> + goto error;
>> + }
>> +
>> + if (server->pending_read_op) {
>> + ecode = BT_ATT_ERROR_UNLIKELY;
>> + goto error;
>> + }
>> +
>> + op = new0(struct async_read_op, 1);
>> + if (!op) {
>> + ecode = BT_ATT_ERROR_INSUFFICIENT_RESOURCES;
>> + goto error;
>> + }
>> +
>> + op->pdu = malloc(bt_att_get_mtu(server->att));
>> + if (!op->pdu) {
>> + free(op);
>> + ecode = BT_ATT_ERROR_INSUFFICIENT_RESOURCES;
>> + goto error;
>> + }
>> +
>> + op->opcode = opcode;
>> + op->server = server;
>> + op->db_data = q;
>> + server->pending_read_op = op;
>> +
>> + process_read_by_type(op);
>> +
>> + return;
>> +
>> +error:
>> + encode_error_rsp(opcode, ehandle, ecode, rsp_pdu);
>> + queue_destroy(q, NULL);
>> + bt_att_send(server->att, BT_ATT_OP_ERROR_RSP, rsp_pdu, 4,
>> + NULL, NULL, NULL);
>> +}
>> +
>> static void exchange_mtu_cb(uint8_t opcode, const void *pdu,
>> uint16_t length, void *user_data)
>> {
>> @@ -283,6 +542,14 @@ static bool gatt_server_register_att_handlers(struct bt_gatt_server *server)
>> if (!server->read_by_grp_type_id)
>> return false;
>>
>> + /* Read By Type */
>> + server->read_by_type_id = bt_att_register(server->att,
>> + BT_ATT_OP_READ_BY_TYPE_REQ,
>> + read_by_type_cb,
>> + server, NULL);
>> + if (!server->read_by_type_id)
>> + return false;
>> +
>> return true;
>> }
>>
>> --
>> 2.1.0.rc2.206.gedb03e5
>>
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>
>
>
> --
> Luiz Augusto von Dentz
Cheers,
Arman
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