Tracker.h

#pragma once
#include "Utils.h"
#include <stdint.h>

#define ACTION_CONNECT 0
#define ACTION_ANNOUNCE 1
#define ACTION_SCRAPE 2
#define ACTION_ERROR 3

#define EVENT_NONE 0
#define EVENT_COMPLATED 1
#define EVENT_STARTED 2
#define EVENT_STOPPED 3

#define OK 0
#define ERROR_UNKNOWN_PROTOCOL 1
#define ERROR_OUT_OF_MEMORY 2

#define RESOURCE_PEERS_TABLE_SIZE 200

//////////////////////////////////////////////////////////
//// Struct - Protocol
//////////////////////////////////////////////////////////

//static InfoHash ZERO_INFOHASH = { 0 };

#pragma pack(push, 1)
typedef union HashInfo_u {
  char data[20];
  struct
  {
    uint32_t key;
    uint64_t pos;
    uint64_t offset;
  };
} InfoHash;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct TrackerRequest_t {
  uint64_t __pad;
  uint32_t action;
} TrackerRequest;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ConnectRequest_t {
  // protocol magic: 0x41727101980
  uint64_t protocol_id;
  uint32_t action;
  uint32_t transaction_id;
} ConnectRequest;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ConnectResponse_t {
  uint32_t action;
  uint32_t transaction_id;
  uint64_t connection_id;
} ConnectResponse;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct AnnounceRequest_t {
  uint64_t connection_id;
  uint32_t action;
  uint32_t transaction_id;
  InfoHash info_hash;
  unsigned char peer_id[20];
  uint64_t downloaded;
  uint64_t left;
  uint64_t uploaded;
  uint32_t event;
  // default = 0 (or IPv6 alway is zero)
  uint32_t address;
  uint32_t key;
  int32_t num_want;
  uint16_t port;
} AnnounceRequest;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct AnnounceResponse_t {
  uint32_t action;
  uint32_t transaction_id;
  uint32_t interval;
  uint32_t leechers;
  uint32_t seeders;
} AnnounceResponse;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct AnnounceResponseIPv4Address_t {
  uint32_t address;
  uint16_t port;
} AnnounceResponseIPv4Address;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct AnnounceResponseIPv6Address_t {
  unsigned char address[16];
  uint16_t port;
} AnnounceResponseIPv6Address;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ScrapeRequest_t {
  uint64_t connection_id;
  // action = 2
  uint32_t action;
  uint32_t transaction_id;
} ScrapeRequest;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ScrapeRequestInfoHash_t {
  InfoHash info_hash;
} ScrapeRequestInfoHash;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ScrapeResponse_t {
  // action = 2
  uint32_t action;
  uint32_t transaction_id;
} ScrapeResponse;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ScrapeResponseInfo_t {
  uint32_t seeders;
  uint32_t completed;
  uint32_t leechers;
} ScrapeResponseInfo;
#pragma pack(pop)


#pragma pack(push, 1)
typedef struct ErrorResponse_t {
  // action = 3
  uint32_t action;
  uint32_t transaction_id;
  char message[256];
} ErrorResponse;
#pragma pack(pop)


_Static_assert(20 == sizeof(InfoHash), "sizeof(union InfoHash_u) != 20");
_Static_assert(16 == sizeof(ConnectRequest), "sizeof(struct ConnectRequest_t) != 16");
_Static_assert(16 == sizeof(ConnectResponse), "sizeof(struct ConnectResponse_t) != 16");
_Static_assert(98 == sizeof(AnnounceRequest), "sizeof(struct AnnounceRequest_t) != 98");
_Static_assert(20 == sizeof(AnnounceResponse), "sizeof(struct AnnounceResponse_t) != 20");
_Static_assert(6 == sizeof(AnnounceResponseIPv4Address), "sizeof(struct AnnounceResponseIPv4Address_t) != 6");
_Static_assert(18 == sizeof(AnnounceResponseIPv6Address), "sizeof(struct AnnounceResponseIPv6Address_t) != 18");
_Static_assert(16 == sizeof(ScrapeRequest), "sizeof(struct ScrapeRequest_t) != 16");
_Static_assert(20 == sizeof(ScrapeRequestInfoHash), "sizeof(struct ScrapeRequestInfoHash_t) != 20");
_Static_assert(8 == sizeof(ScrapeResponse), "sizeof(struct ScrapeResponse_t) != 8");
_Static_assert(12 == sizeof(ScrapeResponseInfo), "sizeof(struct ScrapeResponseInfo_t) != 12");
_Static_assert(264 == sizeof(ErrorResponse), "sizeof(struct ErrorResponse_t) != 264");

//////////////////////////////////////////////////////////
//// Struct - Tables
//////////////////////////////////////////////////////////

typedef struct PeerConnV4_t
{
  uint16_t port;
  uint32_t address;
} PeerConnV4;


struct ResourcePeerIndexTable_t;

typedef struct Resource_t {
  int numOfPeers;
  InfoHash infoHash;
  uint32_t peerIdx[RESOURCE_PEERS_TABLE_SIZE];
} ResourceTable;

typedef struct TrackerContextConfig_t {
  uint32_t announceInterval;
  uint32_t numOfSupportPeers;
  uint32_t numOfSupportTorrents;
} TrackerContextConfig;

typedef struct TrackerContext_t {
  TrackerContextConfig* cfg;
  uint32_t numOfOnlinePeers;
  PeerConnV4* peerPool;
  ResourceTable* resourceTable;
  unsigned char* AvailableBitFieldsTables;
} TrackerContext;


//////////////////////////////////////////////////////////
//// Function
//////////////////////////////////////////////////////////

TrackerContext* CreateTrackerServer(TrackerContextConfig* cfg);
void DeinitTrackerServer(TrackerContext* ctx);
void HandleClientRequestV4(TrackerContext* ctx, uint32_t address, char* rxbuf, int32_t rxlen, char* txbuf, int32_t* txlen);