Typedefs of enums and structs visible to all files that include the library header file. More...

Collaboration diagram for Public Types:

Data Structures
struct	snap_header_t
	Bit field that stores every field of the frame header. It defines the format of the frame. More...

struct	snap_fields_t
	Structure that stores every data necessary to build a new frame (i.e. every field value and size, except the hash bytes). More...

struct	snap_frame_t
	This is the main structure of the library, used in frame decoding, encapsulation, and decapsulation. More...

Enumerations
enum	snap_fieldType_t { SNAP_FIELD_HEADER = 0 , SNAP_FIELD_DEST_ADDRESS = 1 , SNAP_FIELD_SOURCE_ADDRESS = 2 , SNAP_FIELD_PROTOCOL_FLAGS = 3 , SNAP_FIELD_DATA = 4 , SNAP_FIELD_HASH = 5 }
	Values that identify each field of a frame. More...

enum	snap_hdb2_dab_t { SNAP_HDB2_DAB_NO_DEST_ADDRESS = 0 , SNAP_HDB2_DAB_1BYTE_DEST_ADDRESS = 1 , SNAP_HDB2_DAB_2BYTE_DEST_ADDRESS = 2 , SNAP_HDB2_DAB_3BYTE_DEST_ADDRESS = 3 }
	Values for the DAB field of the HDB2 header byte. It defines the number of destination address bytes. More...

enum	snap_hdb2_sab_t { SNAP_HDB2_SAB_NO_SOURCE_ADDRESS = 0 , SNAP_HDB2_SAB_1BYTE_SOURCE_ADDRESS = 1 , SNAP_HDB2_SAB_2BYTE_SOURCE_ADDRESS = 2 , SNAP_HDB2_SAB_3BYTE_SOURCE_ADDRESS = 3 }
	Values for the SAB field of the HDB2 header byte. It defines the number of source address bytes. More...

enum	snap_hdb2_pfb_t { SNAP_HDB2_PFB_NO_PROTOCOL_FLAGS = 0 , SNAP_HDB2_PFB_1BYTE_PROTOCOL_FLAGS = 1 , SNAP_HDB2_PFB_2BYTE_PROTOCOL_FLAGS = 2 , SNAP_HDB2_PFB_3BYTE_PROTOCOL_FLAGS = 3 }
	Values for the PFB field of the HDB2 header byte. It defines the number of protocol specific flags bytes. More...

enum	snap_hdb2_ack_t { SNAP_HDB2_ACK_NOT_REQUESTED = 0 , SNAP_HDB2_ACK_REQUESTED = 1 , SNAP_HDB2_ACK_RESPONSE_ACK = 2 , SNAP_HDB2_ACK_RESPONSE_NACK = 3 }
	Values for the ACK field of the HDB2 header byte. It defines if the sending node requests an ACK/NACK packet in return. It also acts as the actual ACK/NACK response sent from the receiving node. More...

enum	snap_hdb1_cmd_t { SNAP_HDB1_CMD_MODE_DISABLED = 0 , SNAP_HDB1_CMD_MODE_ENABLED = 1 }
	Values for the CMD field of the HDB1 header byte. It indicates whether the command mode is enabled or not. More...

enum	snap_hdb1_edm_t { SNAP_HDB1_EDM_NO_ERROR_DETECTION = 0 , SNAP_HDB1_EDM_3_RETRANSMISSION = 1 , SNAP_HDB1_EDM_8BIT_CHECKSUM = 2 , SNAP_HDB1_EDM_8BIT_CRC = 3 , SNAP_HDB1_EDM_16BIT_CRC = 4 , SNAP_HDB1_EDM_32BIT_CRC = 5 , SNAP_HDB1_EDM_FEC = 6 , SNAP_HDB1_EDM_USER_SPECIFIED = 7 }
	Values for the EDM field of the HDB1 header byte. It defines the error detection method used on the frame. More...

enum	snap_hdb1_ndb_t { SNAP_HDB1_NDB_NO_DATA = 0 , SNAP_HDB1_NDB_1BYTE_DATA = 1 , SNAP_HDB1_NDB_2BYTE_DATA = 2 , SNAP_HDB1_NDB_3BYTE_DATA = 3 , SNAP_HDB1_NDB_4BYTE_DATA = 4 , SNAP_HDB1_NDB_5BYTE_DATA = 5 , SNAP_HDB1_NDB_6BYTE_DATA = 6 , SNAP_HDB1_NDB_7BYTE_DATA = 7 , SNAP_HDB1_NDB_8BYTE_DATA = 8 , SNAP_HDB1_NDB_16BYTE_DATA = 9 , SNAP_HDB1_NDB_32BYTE_DATA = 10 , SNAP_HDB1_NDB_64BYTE_DATA = 11 , SNAP_HDB1_NDB_128BYTE_DATA = 12 , SNAP_HDB1_NDB_256BYTE_DATA = 13 , SNAP_HDB1_NDB_512BYTE_DATA = 14 , SNAP_HDB1_NDB_USER_SPECIFIED = 15 }
	Values for the NDB field of the HDB1 header byte. It defines the number of data/payload bytes. More...

enum	snap_status_t { SNAP_STATUS_IDLE = 0 , SNAP_STATUS_INCOMPLETE = 1 , SNAP_STATUS_VALID = 2 , SNAP_STATUS_ERROR_HASH = -1 , SNAP_STATUS_ERROR_OVERFLOW = -2 }
	Values for the frame status. The frame structure will always be in one of these states. More...

Detailed Description

Typedefs of enums and structs visible to all files that include the library header file.

Enumeration Type Documentation

◆ snap_fieldType_t

enum snap_fieldType_t

Values that identify each field of a frame.

Enumerator
SNAP_FIELD_HEADER	Header (HDB2 and HDB1 bytes).
SNAP_FIELD_DEST_ADDRESS	Destination address.
SNAP_FIELD_SOURCE_ADDRESS	Source address.
SNAP_FIELD_PROTOCOL_FLAGS	Protocol specific flags.
SNAP_FIELD_DATA	Data (payload).
SNAP_FIELD_HASH	Hash value (checksum, CRC-8, CRC-16, etc).

◆ snap_hdb2_dab_t

enum snap_hdb2_dab_t

Values for the DAB field of the HDB2 header byte. It defines the number of destination address bytes.

Enumerator
SNAP_HDB2_DAB_NO_DEST_ADDRESS	Frame has no destination address.
SNAP_HDB2_DAB_1BYTE_DEST_ADDRESS	Frame has a 1-byte destination address.
SNAP_HDB2_DAB_2BYTE_DEST_ADDRESS	Frame has a 2-byte destination address.
SNAP_HDB2_DAB_3BYTE_DEST_ADDRESS	Frame has a 3-byte destination address.

◆ snap_hdb2_sab_t

enum snap_hdb2_sab_t

Values for the SAB field of the HDB2 header byte. It defines the number of source address bytes.

Enumerator
SNAP_HDB2_SAB_NO_SOURCE_ADDRESS	Frame has no source address.
SNAP_HDB2_SAB_1BYTE_SOURCE_ADDRESS	Frame has a 1-byte source address.
SNAP_HDB2_SAB_2BYTE_SOURCE_ADDRESS	Frame has a 2-byte source address.
SNAP_HDB2_SAB_3BYTE_SOURCE_ADDRESS	Frame has a 3-byte source address.

◆ snap_hdb2_pfb_t

enum snap_hdb2_pfb_t

Values for the PFB field of the HDB2 header byte. It defines the number of protocol specific flags bytes.

Enumerator
SNAP_HDB2_PFB_NO_PROTOCOL_FLAGS	Frame has no protocol specific flags.
SNAP_HDB2_PFB_1BYTE_PROTOCOL_FLAGS	Frame has 1 byte of protocol specific flags.
SNAP_HDB2_PFB_2BYTE_PROTOCOL_FLAGS	Frame has 2 bytes of protocol specific flags.
SNAP_HDB2_PFB_3BYTE_PROTOCOL_FLAGS	Frame has 3 bytes of protocol specific flags.

◆ snap_hdb2_ack_t

enum snap_hdb2_ack_t

Values for the ACK field of the HDB2 header byte. It defines if the sending node requests an ACK/NACK packet in return. It also acts as the actual ACK/NACK response sent from the receiving node.

Enumerator
SNAP_HDB2_ACK_NOT_REQUESTED	Sending node does not request an ACK/NACK packet in return.
SNAP_HDB2_ACK_REQUESTED	Sending node requests an ACK/NACK packet in return.
SNAP_HDB2_ACK_RESPONSE_ACK	Receiving node sends an ACK response.
SNAP_HDB2_ACK_RESPONSE_NACK	Receiving node sends an NACK response.

◆ snap_hdb1_cmd_t

enum snap_hdb1_cmd_t

Values for the CMD field of the HDB1 header byte. It indicates whether the command mode is enabled or not.

A node that implements this functionality can respond to requests from other nodes, even when it does not support the format of the received packet. If the command mode is enabled, the first data byte contains a command byte (request or response). Commands in the range 0~127 are requests, and commands in the range 128~255 are responses. The commands 0/128 are for discovering if the node supports the command mode. The commands 1/129 are for discovering the preferred packet structure of the node. The other command values are reserved but not yet defined.

Enumerator
SNAP_HDB1_CMD_MODE_DISABLED	Command mode is disabled.
SNAP_HDB1_CMD_MODE_ENABLED	Command mode is enabled.

◆ snap_hdb1_edm_t

enum snap_hdb1_edm_t

Values for the EDM field of the HDB1 header byte. It defines the error detection method used on the frame.

Note: Some options are not fully supported by this library (see the notes).

Enumerator
SNAP_HDB1_EDM_NO_ERROR_DETECTION	Frame does not contain any information about error detection/correction.
SNAP_HDB1_EDM_3_RETRANSMISSION	The sending node must send the same frame 3 times, and the receiving node should compare the frames in order to detect errors. Note Not supported by this library. It produces the same result as EDM = 0.
SNAP_HDB1_EDM_8BIT_CHECKSUM	Frame has an 8-bit checksum at the end.
SNAP_HDB1_EDM_8BIT_CRC	Frame has an 8-bit CRC at the end.
SNAP_HDB1_EDM_16BIT_CRC	Frame has a 16-bit CRC at the end.
SNAP_HDB1_EDM_32BIT_CRC	Frame has a 32-bit CRC at the end.
SNAP_HDB1_EDM_FEC	Specific FEC (Forward Error Correction) standard to be determined. Note Not supported by this library. It produces the same result as EDM = 0.
SNAP_HDB1_EDM_USER_SPECIFIED	Error detection method defined by the user. Note This library only supports methods that append a hash value of up to 4 bytes into the end of the frame (like the CRC options). The user can only define the hash function (by overriding snap_calculateUserHash()) and the hash value size (by overriding SNAP_SIZE_USER_HASH).

◆ snap_hdb1_ndb_t

enum snap_hdb1_ndb_t

Values for the NDB field of the HDB1 header byte. It defines the number of data/payload bytes.

Enumerator
SNAP_HDB1_NDB_NO_DATA	Frame has no data bytes.
SNAP_HDB1_NDB_1BYTE_DATA	Frame has 1 data byte.
SNAP_HDB1_NDB_2BYTE_DATA	Frame has 2 data bytes.
SNAP_HDB1_NDB_3BYTE_DATA	Frame has 3 data bytes.
SNAP_HDB1_NDB_4BYTE_DATA	Frame has 4 data bytes.
SNAP_HDB1_NDB_5BYTE_DATA	Frame has 5 data bytes.
SNAP_HDB1_NDB_6BYTE_DATA	Frame has 6 data bytes.
SNAP_HDB1_NDB_7BYTE_DATA	Frame has 7 data bytes.
SNAP_HDB1_NDB_8BYTE_DATA	Frame has 8 data bytes.
SNAP_HDB1_NDB_16BYTE_DATA	Frame has 16 data bytes (it might contain padding bytes).
SNAP_HDB1_NDB_32BYTE_DATA	Frame has 32 data bytes (it might contain padding bytes).
SNAP_HDB1_NDB_64BYTE_DATA	Frame has 64 data bytes (it might contain padding bytes).
SNAP_HDB1_NDB_128BYTE_DATA	Frame has 128 data bytes (it might contain padding bytes).
SNAP_HDB1_NDB_256BYTE_DATA	Frame has 256 data bytes (it might contain padding bytes).
SNAP_HDB1_NDB_512BYTE_DATA	Frame has 512 data bytes (it might contain padding bytes).
SNAP_HDB1_NDB_USER_SPECIFIED	Number of data bytes is defined by the user. Note Not supported by this library. It produces the same result as NDB = 0.

◆ snap_status_t

enum snap_status_t

Values for the frame status. The frame structure will always be in one of these states.

Enumerator
SNAP_STATUS_IDLE	Frame is considered empty (it has not received the sync byte yet). The frame structure must be in this state before decoding a new frame.
SNAP_STATUS_INCOMPLETE	Frame has received the sync byte, but it is not complete yet. This state is used only during the decoding process.
SNAP_STATUS_VALID	Frame buffer contains a complete and valid frame.
SNAP_STATUS_ERROR_HASH	The hash value received does not match the value calculated. This state is used only during the decoding process.
SNAP_STATUS_ERROR_OVERFLOW	Frame buffer does not have enough space to store the complete frame.

Data Structures

Enumerations