RFC: connectionless Data Link Metalanguage (cldl) cldl Metalanguage Model. RFC for a connectionless Data Link Metalanguage

Transcription

1 RFC: connectionless Data Link Metalanguage (cldl) This RFC details a specification draft for a UDI metalanguage interfacing UDI Network Protocol drivers to UDI Data Link drivers. The metalanguage proposed here provides unreliable connectionless data link service to the network protocol driver. cldl Metalanguage Model This document identifies two entities: The Data Link Provider (DLP) and the Data Link Service User (DLU) (usually the network protocol driver). A DLP provides unreliable connectionless Data Link functionality above the MAC level. DLUs are children of the DLP. Any DLP can have multiple children, and any DLU can have multiple parents. A DLP instance enumerates all its children at the time it is instantiated by the MA. A DLU can then bind to the DLP by issuing the udi_dlp_bind_req operation over the initial bind channel established by the MA between the DLU and the DLP. A DLP can but need not act as the NSR (Network Service Requestor) as defined by the UDI Network Interface Metalanguage. There is one DLP instance per network interface for any one distinct Data Link protocol. There is one DLU instance for any one distinct network protocol (or entity providing network-level protocol functionality). Any network protocol for which operation over a given data link protocol is defined and desirable can be bound to the corresponding DLP. Consequently, a DLU can utilize various DLPs, according to the desired operation (i.e. IP over Ethernet vs. IP over Wireless LAN). Likewise, one DLP can be used by various DLUs (i.e. IP over Ethernet vs. IPX over Ethernet on the same interface). An external configuration mechanism is needed to set up legal bindings between DLPs and DLUs. Each DLP instance will enumerate one child for each such binding. These bindings shall be based on a system-specific description of the network-level protocol entities (DLUs). DLPs and DLUs implictly agree on an addressing format for the udi_dl_tx_req operation by binding to one another. The addr_type enumeration attribute contains a description of the addressing format a DLP understands. If the DLU understands the same addressing format, they can bind and that addressing format is used to describe destination endpoints. The addressing format also determines the format of the SAP address that the DLU specifies in the udi_dlp_rx_chan_req operation. During the bind operation, the DLP informs the DLU about the QoS guarantees it can make. When creating a transmit channel, the DLU can then specify a default set of QoS constraints to be used for transmission over that channel. However, each packet can also carry its own set of QoS constraints. The Data Link Metalanguage is solely concerned with data transmission and reception. Control operations (such as putting the underlying interface into/out of promiscuous mode, or having it join multicast groups) need to be addressed in a different manner. For instance, a DLP also acting as the NSR could provide a generic GIO interface to allow for configuration operations on the device it supports. Flow control is achieved in a manner similar to that of the NIC Metalanguage. The DLP allocates a pool of control blocks to be used for packet transmission, which it then passes to the DLU using the udi_dlu_tx_rdy operation. Similarly, the DLU allocates a supply of control blocks to be used for packet reception, which is made available to the DLP using the udi_dlp_rx_rdy operation. Page 1 of 29

2 connection-less DL Metalanguage Definitions udi_dlp_ctrl_ops_t typedef const struct { udi_channel_event_ind_op_t *channel_event_ind_op; udi_dlp_bind_req_op_t *dlp_bind_req_op; udi_dlp_unbind_req_op_t *dlp_unbind_req_op; udi_dlp_unbind_ack_op_t *dlp_unbind_ack_op; udi_dlp_rx_chan_req_op_t *dlp_rx_chan_req_op; udi_dlp_tx_chan_req_op_t *dlp_tx_chan_req_op; TODO: Do we need ctl_req? } udi_dlp_ctrl_ops_t; /* DLP control Ops Vector Number */ #define UDI_DLP_CTRL_OPS_NUM 1 A Data Link Driver uses the udi_dlp_ctrl_ops_t structure in a udi_dlp_ctrl_ops_t in a udi_ops_init_t as part of its udi_init_info in order to register its entry points for the Data Link Metalanguage control channel operations. Page 2 of 29

3 udi_dlp_tx_ops_t typedef const struct { udi_channel_event_ind_op_t *channel_event_ind_op; udi_dlp_tx_req_op_t *dlp_tx_req_op; TODO: Do we need expedited service at this level? } udi_dlp_tx_ops_t; /* DLP TX Ops Vector Number */ #define UDI_DLP_TX_OPS_NUM 2 A Data Link Driver uses the udi_dlp_tx_ops_t structure in a udi_ops_init_t as part of its udi_init_info in order to register its entry points for operations over a Data Link Metalanguage transmit channel. Page 3 of 29

4 udi_dlp_rx_ops_t typedef const struct { udi_channel_event_ind_op_t *channel_event_ind_op; udi_dlp_rx_rdy_op_t *dlp_rx_rdy_op; } udi_dlp_rx_ops_t; /* DLP TX Ops Vector Number */ #define UDI_DLP_RX_OPS_NUM 3 A Data Link Driver uses the udi_dlp_rx_ops_t structure in a udi_ops_init_t as part of its udi_init_info in order to register its entry points for operations over a Data Link Metalanguage receive channel. Page 4 of 29

5 udi_dlu_ctrl_ops_t typedef const struct { udi_channel_event_ind_op_t *channel_event_ind_op; udi_dlu_bind_ack_op_t *dlu_bind_ack_op; udi_dlu_unbind_ack_op_t *dlu_unbind_ack_op; udi_dlu_unbind_req_op_t *dlu_unbind_req_op; udi_dlu_rx_chan_ack_op_t *dlu_rx_chan_ack_op; udi_dlu_tx_chan_ack_op_t *dlu_tx_chan_ack_op; TODO: Do we need ctrl_req? } udi_dlu_ctrl_ops_t; /* DLU control Ops Vector Number */ #define UDI_DLU_CTRL_OPS_NUM 4 A Network Protocol Driver uses the udi_dlu_ctrl_ops_t structure in a udi_dlp_ctrl_ops_t in a udi_ops_init_t as part of its udi_init_info in order to register its entry points for the Data Link Metalanguage control channel operations. Page 5 of 29

6 udi_dlu_tx_ops_t typedef const struct { udi_channel_event_ind_op_t *channel_event_ind_op; udi_dlu_tx_rdy_op_t *dlu_tx_rdy_op; } udi_dlu_tx_ops_t; /* DLU TX Ops Vector Number */ #define UDI_DLU_TX_OPS_NUM 5 A Network Protocol Driver uses the udi_dlu_tx_ops_t structure in a udi_ops_init_t as part of its udi_init_info in order to register its entry points for operations over a Data Link Metalanguage transmit channel. Page 6 of 29

7 udi_dlu_rx_ops_t typedef const struct { udi_channel_event_ind_op_t *channel_event_ind_op; udi_dlu_rx_ind_op_t *dlu_rx_ind_op; TODO: Do we need expedited data delivery? } udi_dlu_tx_ops_t; /* DLP RX Ops Vector Number */ #define UDI_DLU_RX_OPS_NUM 6 A Network Protocol Driver uses the udi_dlu_rx_ops_t structure in a udi_ops_init_t as part of its udi_init_info in order to register its entry points for operations over a Data Link Metalanguage receive channel. Page 7 of 29

8 udi_dl_cb_t typedef struct { udi_cb_t gcb; } udi_dl_cb_t; /* Data Link Standard Control Block Number */ #define UDI_DL_STD_CB_NUM 1 The udi_dl_cb_t structure is used for channel operations between a child (DLU) and its parent (DLP) where there is no additional metalanguage information needed in the control block. This control block must be declared by specifying the control block index value UDI_DL_STD_CB_NUM in a udi_cb_init_t in the driver s udi_init_info. Page 8 of 29

9 udi_dl_bind_cb_t typedef struct { udi_cb_t gcb; udi_ubit32_t min_dlpdu_size; udi_ubit32_t max_dlpdu_size; void *qos_caps; TODO: Do we need anything else here? Like media/if type? I think not, rather, everything else should be enumeration attributes, so that we can match drivers based on e.g. if type } udi_dl_bind_cb_t; /* Data Link Bind Control Block Number */ #define UDI_DL_BIND_CB_NUM 2 MEMBERS gcb is the generic control block header which includes a pointer to the scratch space associated with this block and the channel context for the associated channel. The driver may use the scratch space while it owns the control block, but the values are not guaranteed to persist across channel operations. min_dlpdu_size is the minimum size of a Data Link Protocol Data Unit. This represents the minimum number of bytes that make up one packet sent or received by the DLP, including the data link header attached by the DLP. The DLP sets this value in the bind ack operation. max_dlpdu_size is the maximum size of a Data Link Protocol Data Unit. This represents the maximum number of bytes that make up one packet sent or received by the DLP, including the data link header attached by the DLP. The DLP sets this value in the bind ack operation. qos_caps is a pointer to an inline memory structure specifying the quality of service parameters the DLP supports. The DLP sets the contents of this structure before calling the bind ack operation. If NULL, the DLP does not make any quality-of- Service guarantees and any constraints specified for packet transmission will be ignored by the DLP. The udi_dl_bind_cb_t structure is used for the udi_dlp_bind_req and udi_dlu_bind_ack operations between a child (DLU) and its parent (DLP). This structure is empty on the udi_dlp_bind_req operation, and its members are filled in by the DLP for the corresponding udi_dlu_bind_ack operation. This control block must be declared by specifying the control block index value UDI_DL_BIND_CB_NUM in a udi_cb_init_t in the driver s udi_init_info. Page 9 of 29

10 The structure pointed to by the qos_caps member is defined as follows: struct udi_qos_capabilities { udi_ubit8_t qos_type; /* type of constraints supported; either QOS_GENERIC or QOS_EXPLICIT */ udi_boolean_t flows_supported; udi_ubit8_t service_class_supported; /* bit mask of SVC_* constants for each supported service class */ udi_uibt32_t max_pdv; udi_ubit32_t max_pdv_tolerance; udi_ubit32_t max_plr; udi_ubit32_t max_ptd; udi_ubit32_t max_mbs; udi_ubit32_t max_mdr; udi_ubit32_t max_pdr; udi_ubit32_t max_sdr; }; #define QOS_GENERIC 0 /* supports generic QoS constraints */ #define QOS_EXPLICIT 1 /* supports explicit constraints */ #define SVC_CBR 1 /* constant bit rate service */ #define SVC_VBR_RT 2 /* real-time variable bit rate */ #define SVC_VBR_NRT 4 /* non-real-time variable bit rate */ #define SVC_ABR 8 /* available bit rate service */ #define SVC_UBR 16 /* unspecified bit rate service */ Each max_* field will be set to the maximum value supported by the DLP, or to 0 if the corresponding field in a QoS constraint structure is not supported. Page 10 of 29

11 udi_dlp_bind_req void udi_dlp_bind_req ( udi_dl_bind_cb_t *cb); ARGUMENTS cb is a pointer to a Data Link Metalanguage bind control block. The fields of this control block are to be initialized by the binding DLP, which will return the control block to the DLU in a subsequent udi_dlu_bind_ack operation. TARGET CHANNEL The udi_dlp_bind_req operation is issued over the Data Link Metalanguage control channel, which is also the primary channel initially established by the MA to bind the primary region of the DLP to the primary region of the DLU. udi_dlp_bind_req is used to associate, or bind a channel between the DLU and the DLP. Page 11 of 29

12 udi_dlu_bind_ack void udi_dlu_bind_ack ( udi_dl_bind_cb_t *cb, udi_status_t status); ARGUMENTS cb is a pointer to a Data Link Metalanguage bind control block. status indicates the sucess or failure of the data link bind request. TARGET CHANNEL The udi_dlu_bind_ack operation is issued over the Data Link Metalanguage control channel over which the corresponding udi_dlp_bind_req operation was received. Response to a udi_dlp_bind_req operation. The DLP uses this to acknowledge the bind operation to the DLU and to signal the success of the bind operation. TODO: Explain Status codes. Page 12 of 29

13 udi_dlp_unbind_req void udi_dlp_unbind_req ( udi_dl_cb_t *cb); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. TARGET CHANNEL The udi_dlp_unbind_req operation is issued over the Data Link Metalanguage control channel. The udi_dlp_unbind_req operation is used when the DLU wishes to close down an active binding between itself and the DLP. All data transfer ceases, any queued data is discarded, and the data channel(s) are closed. The control channel may be used to issuse a subsequent udi_dlp_bind_req to the DLP if desired or it may also be closed. Page 13 of 29

14 udi_dlu_unbind_ack void udi_dlu_unbind_ack ( udi_dl_cb_t *cb, udi_status_t status); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. status indicates the success or failure of the data link unbind request. TARGET CHANNEL The udi_dlu_unbind_ack operation is issued over the Data Link Metalanguage control channel over which the corresponding udi_dlp_unbind_req operation was received. Response to a udi_dlp_unbind_req operation. After this operation is performed, the DLU will no longer attempt to transmit packets or to establish additional data transfer channels between itself and the DLP unless another udi_dlp_bind_req has been issued and handshaked before. Likewise, the DLP will stop delivering incoming packets to the DLU unless it has been bound again. TODO: Explain Status codes. Page 14 of 29

15 udi_dlu_unbind_req void udi_dlu_unbind_req ( udi_dl_cb_t *cb); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. TARGET CHANNEL The udi_dlu_unbind_req operation is issued over the Data Link Metalanguage control channel. The udi_dlu_unbind_req operation is used when the DLP wishes to close down an active binding between itself and the DLU. All data transfer ceases, any queued data is discarded, and the data channel(s) are closed. The control channel may be used by the DLU to issue a subsequent udi_dlp_bind_req to the DLP if desired or it may also be closed. Page 15 of 29

16 udi_dlp_unbind_ack void udi_dlp_unbind_ack ( udi_dl_cb_t *cb, udi_status_t status); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. status indicates the sucess or failure of the data link unbind request. TARGET CHANNEL The udi_dlp_unbind_ack operation is issued over the same Data Link Metalanguage control channel through which the corresponding udi_dlu_unbind_req operation was received. Response to a udi_dlu_unbind_req operation. After this operation is performed, the DLU will no longer attempt to transmit packets or to establish additional data transfer channels between itself and the DLP unless another udi_dlp_bind_req has been issued and handshaked before. Likewise, the DLP will stop delivering incoming packets to the DLU unless it has been bound again. TODO: Explain Status codes. Page 16 of 29

17 udi_dlp_rx_chan_req void udi_dlp_rx_chan_req ( udi_dl_cb_t *cb, udi_index_t rx_chan_index, void *dlp_sap_addr); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. rx_chan_index is the index of the data receive channel to be created between the DLP and the DLU by synchronizing via udi_channel_spawn operations. dlp_sap_addr is a protocol-specific description of a service access point address to be used for that receive channel. The service access point address specifies which datalink packet should be forwarded over the requested receive channel. The pointer itself is set by the environment, and must not be modified by the driver. TARGET CHANNEL The udi_dlp_rx_chan_req operation is issued over the Data Link Metalanguage control channel. The udi_dlp_rx_chan_req operation is used to establish a receive data transfer channel between the DLP and the DLU. The DLU spawns one end of the data transfer channel and then issues this request, which shall cause the DLP to create its end of the same channel (using the rx_chan_index parameter to identify the channel being spawned). This channel will then be used by the DLP to report incoming packets to the DLU. The dlp_sap_addr parameter encodes the address of a service access point (or service user) in a protocol-specific manner. This parameter allows the DLP to decide which incoming packets should be indicated to the service user over the receive channel. The size and layout of the dlp_sap_addr structure must be specified using the inline_size and inline_layout members of the udi_cb_init_t structure used to associate this control block to a control block index (i.e. dlp_sap_addr is a UDI_DL_INLINE_DRIVER_TYPED field). TODO: Better explain SAP address. Rename SAP address, as this is probably a misnomer. What s a better name? Page 17 of 29

18 udi_dlu_rx_chan_ack void udi_dlu_rx_chan_ack ( udi_dl_cb_t *cb, udi_status_t status ); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. status indicates the success or failure of the channel allocation request. TARGET CHANNEL The udi_dlu_rx_chan_ack operation is issued over the same Data Link Metalanguage control channel that the corresponding udi_dlp_rx_chan_req was delivered over. Response to udi_dlp_rx_chan_req. The udi_dlu_rx_chan_ack operation acknowledges the channel creation request and informs the DLU about the success of the request. If the operation was successful, the DLP will henceforward deliver incoming packets over the newly-bound channel that match the SAP specification identified by the dlp_sap parameter in the udi_dlp_chan_req operation. TODO: Explain Status codes. Page 18 of 29

19 udi_dlp_tx_chan_req void udi_dlp_tx_chan_req ( udi_dl_cb_t *cb, udi_index_t tx_chan_index, void *default_qos ); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. tx_chan_index is the index of the data transmit channel to be created between the DLP and the DLU by synchronizing via udi_channel_spawn operations. default_qos is a pointer to an inlined memory structure describing the default Quality-of- Service constraints to be used for transmitting on the transmit channel to be created. This parameter can be NULL, indicating that the DLU does not request default QoS constraints. TARGET CHANNEL The udi_dlp_tx_chan_req operation is issued over the Data Link Metalanguage control channel. The udi_dlp_tx_chan_req operation is used to establish a transmit data transfer channel between the DLP and the DLU. The DLU spawns one end of the data transfer channel and then issues this request, which shall cause the DLP to create its end of the same channel (using the tx_chan_index parameter to identify the channel). This channel will then be used by the DLU to transmit data over the DLP. The format of the structure pointed to by the default_qos argument is as follows: struct udi_qos_constraints { union { udi_ubit32_t flow_id; /* id of flow for this packet */ udi_ubit32_t flow_type; /* type of flow for this packet */ } _u; }; struct { udi_ubit32_t expiry; /* system ticks at which packet expires */ udi_ubit32_t priority; /* priority of packet */ } generic; struct { udi_ubit8_t service_class; /* type of service guarantee */ udi_ubit32_t pdv; /* packet delay variation */ udi_ubit32_t pdv_tolerance; /* tolerance of pdv */ udi_ubit32_t plr; /* packet loss ratio */ udi_ubit32_t ptd; /* packet transfer delay */ udi_ubit32_t mbs; /* maximum burst size */ udi_ubit32_t mdr; /* minimum data rate */ udi_ubit32_t pdr; /* peak data rate */ udi_ubit32_t sdr; /* sustainable data rate */ } explicit; Page 19 of 29

20 #define SVC_CBR 1 /* constant bit rate service */ #define SVC_VBR_RT 2 /* real-time variable bit rate */ #define SVC_VBR_NRT 4 /* non-real-time variable bit rate */ #define SVC_ABR 8 /* available bit rate service */ #define SVC_UBR 16 /* unspecified bit rate service */ The DLU should only set constraint options that the DLP supports. The DLP must ignore options that it does not support. The DLU must only use ranges for each option that are supported by the DLP. Page 20 of 29

21 udi_dlu_tx_chan_ack void udi_dlu_tx_chan_ack ( udi_dl_cb_t *cb, udi_status_t status ); ARGUMENTS cb is a pointer to a Data Link Metalanguage standard control block. status indicates the success or failure of the channel allocation request. TARGET CHANNEL The udi_dlu_tx_chan_ack operation is issued over the same Data Link Metalanguage control channel that the corresponding udi_dlp_tx_chan_req was delivered over. Response to udi_dlp_tx_chan_req. The udi_dlu_tx_chan_ack operation acknowledges the channel creation request and informs the DLU about the success of the request. If the operation was successful, the DLU can start transmitting packets over the newly-bound channel. TODO: Explain Status codes. Page 21 of 29

22 udi_dl_tx_cb_t typedef struct ( udi_cb_t gcb; udi_dl_tx_cb_t *chain; udi_buf_t *tx_buf; void *tx_addr; void *qos_constraints; TODO: Do we need completion_urgent or anything else? } udi_dl_tx_cb_t; /* Data Link Transmit Control Block Group Number */ #define UDI_DL_TX_CB_NUM 3 MEMBERS gcb is the generic control block which includes a pointer to the scratch space associated with this block and the channel context for the associated channel. The driver may use the scratch space while it owns the control block, but the values are not guaranteed to persist across channel operations. chain is a pointer to the next udi_dl_tx_cb_t structure (and associated SDU buffer) for this operation. The DLP and DLU will use this field to batch a number of transmit requests or ready s into a single metalanguage operation. The DLP, DLU, or environment are free to divide a chain at any point and implement explicit operations for each resulting portion of the chain, but performance concerns would indicate that processing the entire chain as a batch is highly desirable. The end of a chain is indicated by a NULL pointer. tx_buf is the buffer describing the SDU to be transmitted. This field must be NULL for the udi_dlu_tx_rdy operation and is used only for the udi_dlp_tx_req operation, for which the contents of the buffer are guaranteed to be preserved across a channel. tx_addr is a pointer to an inline memory structure describing the address to which the attached SDU should be sent. The format of this structure is protocol-specific. The pointer itself is set by the environment when the control block is allocated, and must not be modified by the driver. qos_constraints is a pointer to an inline memory structure describing the Quality-of- Service constraints associated with the attached SDU. The pointer itself is set by the environment when the control block is allocated, and must not be modified by the driver. For the format of this structure, refer to the description of udi_dlp_tx_chan_req. The udi_dl_tx_cb_t structure is passed from the DLP to the DLU to indicate a capability for transmitting a SDU; the DLU subsequently attaches an SDU buffer to this control block and returns it to the DLP for transmission. The DLU can only pass SDUs to the DLP when it has available control blocks, thereby implementing flow control between the Page 22 of 29

23 DLP and the DLU by requiring the DLP to supply the DLU with all usable udi_dl_tx_cb_t structures (i.e. the DLU must not allocate structures of this type). This control block must be declared by specifying the control block index value UDI_DL_TX_CB_NUM in a udi_cb_init_t in the driver s udi_init_info. The size and layout of the tx_addr structure must be specified using the inline_size and inline_layout members of that udi_cb_init_t structure (i.e. tx_addr is a UDI_DL_INLINE_DRIVER_TYPED field). The members of the qos_constraints structure must be set by the DLU prior to requesting SDU delivery using the udi_dl_tx_req operation. Only members supported by the DLP should be set by the DLU. Unsupported members must be ignored by the DLP. Only values from the ranges supported by the DLP must be used by the DLU. The DLP informs the DLU of the members and ranges it supports by filling in the members of the qos_constraints structure using the bind ack operation. Page 23 of 29

24 udi_dlu_tx_rdy void udi_dlu_tx_rdy ( udi_dl_tx_cb_t *cb ); ARGUMENTS cb is a pointer to a Data Link Metalanguage transmit control block. TARGET CHANNEL The udi_dlu_tx_rdy operation is issued over a Data Link Metalanguage transmit channel that was previously established using the udi_dlp_tx_chan_req and udi_dlu_tx_chan_ack operations. The udi_dlu_tx_rdy operation is used to indicate to the DLU that the DLP can transmit a SDU when the DLU has one available. The DLU maintains a pool of control blocks of type udi_dl_tx_cb_t for SDU transmission. The udi_dlu_tx_rdy operation makes an additional control block available to the DLU, which can then start or continue transmitting over the channel associated with the control block. This is used to perform flow control. Multiple udi_dl_tx_cb_t structures can be chained together (using the chain pointer). Single control blocks as well as a chain of control blocks can be passed using this operation. Page 24 of 29

25 udi_dlp_tx_req void udi_dlp_tx_req ( udi_dl_tx_cb_t *cb ); ARGUMENTS cb is a pointer to a Data Link Metalanguage transmit control block. TARGET CHANNEL The udi_dlp_tx_req operation is issued over a Data Link Metalanguage transmit channel that was previously established using the udi_dlp_tx_chan_req and udi_dlu_tx_chan_ack operations. The udi_dlp_tx_req operation is called by the DLU to pass one or more SDU buffers to the DLP for transmission over the DLP's associated interface. Each SDU buffer is attached to a udi_dl_tx_cb_t control block. Multiple packet buffers may be passed by chaining control blocks together (using the chain field in the udi_dl_tx_cb_t structure). Each packet buffer represents one Data Link SDU (Service Data Unit), i.e. one higher-level protocol PDU (Protocol Data Unit). Each control block has a Quality-of-Service constraint structure associated with it, which the DLP will typically use to enforce the imposed requirements at the data-link level. Page 25 of 29

26 udi_dl_rx_cb_t typedef struct ( udi_cb_t gcb; udi_dl_rx_cb_t *chain; void *qos_constraints; TODO: Do we need rx_status or anything else? Do we even need qos_constraints? } udi_dl_rx_cb_t; /* Data Link Transmit Control Block Group Number */ #define UDI_DL_RX_CB_NUM 4 MEMBERS gcb is the generic control block which includes a pointer to the scratch space associated with this block and the channel context for the associated channel. The driver may use the scratch space while it owns the control block, but the values are not guaranteed to persist across channel operations. chain is a pointer to the next udi_dl_rx_cb_t structure (and associated SDU buffer) for this operation. The DLP and DLU will use this field to batch a number of transmit requests or ready s into a single metalanguage operation. The DLP, DLU, or environment are free to divide a chain at any point and implement explicit operations for each resulting portion of the chain, but performance concerns would indicate that processing the entire chain as a batch is highly desirable. The end of a chain is indicated by a NULL pointer. rx_buf is the buffer containing the SDU that has been received. This field is used to pass an empty buffer to the DLP (rx_buf->buf_size == 0) in the udi_dlp_rx_rdy operation. It is filled in with the actual SDU for each udi_dlu_rx_ind operation. qos_constraints is a pointer to an inline memory structure describing the Quality-of- Service constraints associated with the attached SDU. The pointer itself is set by the environment and must not be modified by the driver. The format of the structure pointed to by this pointer is specified in the definition of the udi_dl_tx_cb_t structure. The udi_dl_rx_cb_t structure is passed from the DLU to the DLP to indicate a capability for receiving a SDU; the DLP subsequently attaches SDU and QoS-constraint buffers to this control block and returns it to the DLU upon valid reception of a relevant SDU. Only successfully received SDUs will be processed and reported to the DLU. This control block must be declared by specifying the control block index value UDI_DL_RX_CB_NUM in a udi_cb_init_t in the driver s udi_init_info. Page 26 of 29

27 udi_dlp_rx_rdy void udi_dlp_rx_rdy ( udi_dl_rx_cb_t *cb ); ARGUMENTS cb is a pointer to a Data Link Metalanguage receive control block. TARGET CHANNEL The udi_dlp_rx_rdy operation is issued over a Data Link Metalanguage receive channel that was previously established using the udi_dlp_rx_chan_req and udi_dlu_rx_chan_ack operations. The udi_dlp_rx_rdy operation is used to indicate to the DLP that the DLU can process a SDU when the DLP receives one from the underlying interface. The DLP maintains a pool of control blocks of type udi_dl_rx_cb_t for SDU reception. The udi_dlp_rx_rdy operation makes an additional colntrol block available to the DLU, which can then start or continue transmitting over the channel associated with the control block. This is used to perform flow control. Multiple udi_dl_rx_cb_t structures can be chained together (using the chain pointer). Single control blocks as well as a chain of control blocks can be passed using this operation. Page 27 of 29

28 udi_dlu_rx_ind void udi_dlu_rx_ind ( udi_dl_rx_cb_t *cb ); ARGUMENTS cb is a pointer to a Data Link Metalanguage receive control block. TARGET CHANNEL The udi_dlu_rx_ind operation is issued over a Data Link Metalanguage receive channel that was previously established using the udi_dlp_rx_chan_req and udi_dlu_rx_chan_ack operations. The udi_dlu_rx_ind operation is called by the DLP to indicate to the DLU that a relevant network-level SDU has been received by the data link driver. Only SDUs that match the SAP address specified when the receive channel was created will be reported over that receive channel. Only valid SDUs will be reported, erroneous data link packets will be silently dropped. The cb can point to a single udi_dl_rx_cb_t structure, or multiple structures can be chained together using the chain pointer in the structure. Once the DLU is done processing the SDU contained in this (these) control block s (blocks ) rx_buf field, the control block (blocks) are returned to the DLP using the udi_dlp_rx_rdy operation. Page 28 of 29

29 Enumeration Attributes Note: For all attributes of type UDI_ATTR_TYPE_STRING in the following table, the size range indication includes the terminating NUL character. ATTRIBUTE TYPE SIZE dl_name UDI_ATTR_STRING Name of the Data Link Protocol supported by this DLP. TODO: Define known names in this spec. dl_rev UDI_ATTR_UBIT32 4 addr_type UDI_ATTR_STRING np_name UDI_ATTR_STRING Revision of the Data Link Protocol supported by this DLP. Name identifying a format for addressing information understood by this DLP. System name of a network-level protocol entity that can be bound to this DLP. TODO: Do we need this? Shouldn t bindings be enforced by directed enumeration? if_name UDI_ATTR_STRING System Interface name this DLP is bound to. if_media UDI_ATTR_STRING 1..8 Media type string as defined in NIC meta. identifier UDI_ATTR_STRING physical_label UDI_ATTR_STRING String representation of the Factory MAC address of the interface that this DLP supports, encoded in the same way as the attribute with the same name in the NIC meta. Driver-specified string uniquely identifying this DLP instance (optional). TODO: Define Attribute Ranking- Page 29 of 29