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.
> +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.
> + 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
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