dat-thang/extra/dat-dpi/inc/dat_wire.h

#ifndef DAT_WIRE_H
#define DAT_WIRE_H
#include <stddef.h>
#include <stdint.h>

enum dat_message_type {
	DAT_MSG_FEED = 0,
	DAT_MSG_HANDSHAKE = 1,
	DAT_MSG_INFO = 2,
	DAT_MSG_HAVE = 3,
	DAT_MSG_UNHAVE = 4,
	DAT_MSG_WANT = 5,
	DAT_MSG_UNWANT = 6,
	DAT_MSG_REQUEST = 7,
	DAT_MSG_CANCEL = 8,
	DAT_MSG_DATA = 9,
	DAT_MSG_EXTENSION = 15
};

typedef struct dat_feed_open {
	uint8_t discovery_key[32];
	uint8_t nonce[24];
	int has_nonce;
} dat_feed_open_t;

typedef struct dat_wire_message {
	uint64_t channel;
	uint64_t type;
	const uint8_t *payload;
	size_t payload_len;
} dat_wire_message_t;

#define DAT_PROTOCOL_BYTES 32u
#define DAT_PEER_ID_BYTES 32u
#ifndef DAT_NETWORK_PROTOCOL
#define DAT_NETWORK_PROTOCOL "cesspool"
#endif
/*
 * The exact protocol token lives in the repository-root NETWORK_PROTOCOL
 * file. The Cesspool handshake carries it in `userData`; legacy Hypercore V6
 * omits that application-owned field and uses the token to select its
 * discovery namespace and wire mode. This checkout defaults to `cesspool`.
 */
typedef struct dat_handshake {
	uint8_t protocol[DAT_PROTOCOL_BYTES];
	uint8_t peer_id[DAT_PEER_ID_BYTES];
	uint64_t capabilities;
	int has_peer_id;
} dat_handshake_t;
int dat_handshake_init(dat_handshake_t *handshake,
		       const uint8_t peer_id[DAT_PEER_ID_BYTES],
		       uint64_t capabilities);
int dat_handshake_protocol_matches(const dat_handshake_t *handshake);
typedef struct dat_range { uint64_t start; uint64_t length; } dat_range_t;
typedef struct dat_info { uint8_t uploading; uint8_t downloading; } dat_info_t;
typedef struct dat_request { uint64_t index; uint64_t bytes; uint8_t want_hash; uint8_t want_nodes; } dat_request_t;
#define DAT_DATA_MAX_NODES 128u
typedef struct dat_data_node {
	uint64_t index;
	uint64_t length;
	uint8_t hash[32];
} dat_data_node_t;
typedef struct dat_data {
	uint64_t index;
	const uint8_t *value;
	size_t value_len;
	const uint8_t *proof;
	size_t proof_len;
	dat_data_node_t nodes[DAT_DATA_MAX_NODES];
	size_t node_count;
	uint8_t signature[64];
	int has_signature;
} dat_data_t;
typedef struct dat_cancel { uint64_t index; } dat_cancel_t;
typedef struct dat_extension {
	uint64_t id;
	const uint8_t *message;
	size_t message_len;
} dat_extension_t;

/* Hypercore frames are length-prefixed; headers pack channel and type. */
int dat_wire_encode(const dat_wire_message_t *message, uint8_t *out,
		    size_t capacity, size_t *written);
int dat_wire_decode(dat_wire_message_t *message, const uint8_t *input,
		    size_t input_len, size_t *consumed);
int dat_handshake_encode(const dat_handshake_t *handshake, uint8_t *out,
			 size_t capacity, size_t *written);
int dat_handshake_decode(dat_handshake_t *handshake, const uint8_t *input,
			 size_t input_len);
int dat_feed_open_encode(const dat_feed_open_t *feed, uint8_t *out,
			 size_t capacity, size_t *written);
int dat_feed_open_decode(dat_feed_open_t *feed, const uint8_t *input,
			 size_t input_len);
int dat_range_encode(const dat_range_t *range, uint8_t *out, size_t capacity, size_t *written);
int dat_range_decode(dat_range_t *range, const uint8_t *input, size_t input_len);
/* WANT omits length to mean through the current end of a non-live feed. */
int dat_want_decode(dat_range_t *range, const uint8_t *input, size_t input_len,
		    uint64_t feed_length);
int dat_info_encode(const dat_info_t *info, uint8_t *out, size_t capacity,
		    size_t *written);
int dat_info_decode(dat_info_t *info, const uint8_t *input, size_t input_len);
int dat_request_encode(const dat_request_t *request, uint8_t *out, size_t capacity, size_t *written);
int dat_request_decode(dat_request_t *request, const uint8_t *input, size_t input_len);
int dat_data_encode(const dat_data_t *data, uint8_t *out, size_t capacity, size_t *written);
int dat_data_decode(dat_data_t *data, const uint8_t *input, size_t input_len);
int dat_cancel_encode(const dat_cancel_t *cancel, uint8_t *out, size_t capacity, size_t *written);
int dat_cancel_decode(dat_cancel_t *cancel, const uint8_t *input, size_t input_len);
int dat_extension_encode(const dat_extension_t *extension, uint8_t *out, size_t capacity, size_t *written);
int dat_extension_decode(dat_extension_t *extension, const uint8_t *input, size_t input_len);
#endif