src/ncm_protocol.h

 
#ifndef __NCM_PROTOCOL_H
#define __NCM_PROTOCOL_H
 
#include <stdint.h>
 
/*******************************************************************************
 * NCM Control Request Codes (CDC class-specific)
 ******************************************************************************/
#define NCM_SET_ETHERNET_MULTICAST_FILTERS      (0x40)
#define NCM_SET_ETHERNET_PM_PATTERN_FILTER      (0x41)
#define NCM_GET_ETHERNET_PM_PATTERN_FILTER      (0x42)
#define NCM_SET_ETHERNET_PACKET_FILTER          (0x43)
#define NCM_GET_ETHERNET_STATISTIC              (0x44)
#define NCM_GET_NTB_PARAMETERS                  (0x80)
#define NCM_GET_NET_ADDRESS                     (0x81)
#define NCM_SET_NET_ADDRESS                     (0x82)
#define NCM_GET_NTB_FORMAT                      (0x83)
#define NCM_SET_NTB_FORMAT                      (0x84)
#define NCM_GET_NTB_INPUT_SIZE                  (0x85)
#define NCM_SET_NTB_INPUT_SIZE                  (0x86)
#define NCM_GET_MAX_DATAGRAM_SIZE               (0x87)
#define NCM_SET_MAX_DATAGRAM_SIZE               (0x88)
#define NCM_GET_CRC_MODE                        (0x89)
#define NCM_SET_CRC_MODE                        (0x8A)
 
/*******************************************************************************
 * NCM Notification Codes
 ******************************************************************************/
#define NCM_NOTIFICATION_NETWORK_CONNECTION     (0x00)
#define NCM_NOTIFICATION_RESPONSE_AVAILABLE     (0x01)
#define NCM_NOTIFICATION_CONNECTION_SPEED_CHANGE (0x2A)
 
/*******************************************************************************
 * NCM NTB Signatures
 ******************************************************************************/
#define NCM_NTH16_SIGNATURE                     (0x484D434E)  // "NCMH" little-endian
#define NCM_NTH32_SIGNATURE                     (0x686D636E)  // "ncmh" little-endian
#define NCM_NDP16_SIGNATURE_NCM0                (0x304D434E)  // "NCM0" little-endian (no CRC)
#define NCM_NDP16_SIGNATURE_NCM1                (0x314D434E)  // "NCM1" little-endian (with CRC)
#define NCM_NDP32_SIGNATURE_NCM0                (0x306D636E)  // "ncm0" little-endian
#define NCM_NDP32_SIGNATURE_NCM1                (0x316D636E)  // "ncm1" little-endian
 
/*******************************************************************************
 * NCM Constants
 ******************************************************************************/
#define NCM_MAX_SEGMENT_SIZE                    (1514)   // Standard Ethernet frame
#define NCM_MAX_DATAGRAM_SIZE                   (1514)   // Max datagram (Ethernet MTU + header)
#define NCM_MIN_NTB_SIZE                        (2048)   // Minimum NTB size
#define NCM_MAX_NTB_SIZE                        (2048)   // Maximum NTB size we support (reduced for DTCM)
#define NCM_NTB_ALIGNMENT                       (4)      // NTB alignment requirement
#define NCM_NDP_ALIGNMENT                       (4)      // NDP alignment requirement
#define NCM_DATAGRAM_ALIGNMENT                  (4)      // Datagram alignment
 
// NTH16 header size
#define NCM_NTH16_SIZE                          (12)
 
// NDP16 header size (without entries)
#define NCM_NDP16_HEADER_SIZE                   (8)
 
// Each NDP16 entry is 4 bytes (2-byte index + 2-byte length)
#define NCM_NDP16_ENTRY_SIZE                    (4)
 
// Ethernet frame limits
#define NCM_ETHER_ADDR_SIZE                     (6)
#define NCM_ETHER_MAX_FRAME_SIZE                (1514)   // Without VLAN
#define NCM_ETHER_MTU                           (1500)
 
/*******************************************************************************
 * NCM Format Flags
 ******************************************************************************/
#define NCM_NTB_FORMAT_NTB16                    (0x0000)
#define NCM_NTB_FORMAT_NTB32                    (0x0001)
 
/*******************************************************************************
 * NCM bmNetworkCapabilities flags
 ******************************************************************************/
#define NCM_NCAP_PACKET_FILTER                  (1 << 0)
#define NCM_NCAP_NET_ADDRESS                    (1 << 1)
#define NCM_NCAP_ENCAP_COMMAND                  (1 << 2)
#define NCM_NCAP_MAX_DATAGRAM                   (1 << 3)
#define NCM_NCAP_CRC_MODE                       (1 << 4)
#define NCM_NCAP_NTB_INPUT_SIZE_8BYTE           (1 << 5)
 
/*******************************************************************************
 * NCM Packet Filter Bits (same as NDIS/RNDIS)
 ******************************************************************************/
#define NCM_PACKET_TYPE_PROMISCUOUS             (1 << 0)
#define NCM_PACKET_TYPE_ALL_MULTICAST           (1 << 1)
#define NCM_PACKET_TYPE_DIRECTED                (1 << 2)
#define NCM_PACKET_TYPE_BROADCAST               (1 << 3)
#define NCM_PACKET_TYPE_MULTICAST               (1 << 4)
 
/*******************************************************************************
 * NCM Structures
 ******************************************************************************/
 
#pragma pack(push, 1)

typedef struct {
    uint16_t wLength;               // Size of this structure (28)
    uint16_t bmNtbFormatsSupported; // Bit 0: 16-bit NTB, Bit 1: 32-bit NTB
    uint32_t dwNtbInMaxSize;        // Max IN NTB size
    uint16_t wNdpInDivisor;         // Divisor for IN NDP alignment
    uint16_t wNdpInPayloadRemainder;// Remainder for IN NDP alignment
    uint16_t wNdpInAlignment;       // Alignment for IN NDP
    uint16_t wReserved;             // Reserved (0)
    uint32_t dwNtbOutMaxSize;       // Max OUT NTB size
    uint16_t wNdpOutDivisor;        // Divisor for OUT NDP alignment
    uint16_t wNdpOutPayloadRemainder;// Remainder for OUT NDP alignment
    uint16_t wNdpOutAlignment;      // Alignment for OUT NDP
    uint16_t wNtbOutMaxDatagrams;   // Max datagrams per OUT NTB (0 = no limit)
} ncm_ntb_parameters_t;

typedef struct {
    uint32_t dwSignature;           // "NCMH" = 0x484D434E
    uint16_t wHeaderLength;         // Size of this header (12)
    uint16_t wSequence;             // Sequence number, wraps
    uint16_t wBlockLength;          // Total NTB size in bytes
    uint16_t wNdpIndex;             // Offset to first NDP16
} ncm_nth16_t;

typedef struct {
    uint16_t wDatagramIndex;        // Offset of datagram in NTB
    uint16_t wDatagramLength;       // Length of datagram
} ncm_ndp16_entry_t;

typedef struct {
    uint32_t dwSignature;           // "NCM0" = 0x304D434E (no CRC)
    uint16_t wLength;               // Size of NDP16 including entries
    uint16_t wNextNdpIndex;         // Offset to next NDP16 or 0
    // ncm_ndp16_entry_t entries[];  // Variable length array follows
} ncm_ndp16_t;

typedef struct {
    uint8_t  bmRequestType;         // 0xA1 (Device-to-host, Class, Interface)
    uint8_t  bNotificationCode;     // NETWORK_CONNECTION
    uint16_t wValue;                // 0 = disconnected, 1 = connected
    uint16_t wIndex;                // Interface number
    uint16_t wLength;               // 0
} ncm_notification_network_t;

typedef struct {
    uint8_t  bmRequestType;         // 0xA1
    uint8_t  bNotificationCode;     // CONNECTION_SPEED_CHANGE
    uint16_t wValue;                // 0
    uint16_t wIndex;                // Interface number
    uint16_t wLength;               // 8
    uint32_t DLBitRate;             // Downstream bit rate (bps)
    uint32_t ULBitRate;             // Upstream bit rate (bps)
} ncm_notification_speed_t;

typedef struct {
    uint32_t dwNtbInMaxSize;        // Max NTB size host will send
    uint16_t wNtbInMaxDatagrams;    // Max datagrams per NTB
    uint16_t wReserved;             // Reserved
} ncm_ntb_input_size_t;
 
#pragma pack(pop)

typedef enum {
    NCM_STATE_DISCONNECTED = 0,     // USB not configured or alt setting 0
    NCM_STATE_CONFIGURED,           // USB configured, alt setting 0 (no data endpoints)
    NCM_STATE_CONNECTED             // Alt setting 1 selected, data endpoints active
} ncm_state_t;

typedef enum {
    NCM_TX_IDLE = 0,
    NCM_TX_SENDING,
    NCM_TX_COMPLETE
} ncm_tx_state_t;

typedef enum {
    NCM_RX_IDLE = 0,
    NCM_RX_RECEIVING,
    NCM_RX_PROCESSING,
    NCM_RX_COMPLETE
} ncm_rx_state_t;
 
#endif /* __NCM_PROTOCOL_H */