main.c

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <stdlib.h>

#include "Tracker.h"

#pragma comment(lib, "ws2_32.lib")

void PrintClientHostnameAndPort(SOCKADDR_IN clientAddr) {
  char hostname[16] = { 0 };
  inet_ntop(AF_INET, &clientAddr.sin_addr, hostname, 16);
  printf("%s:%u ", hostname, swap16(clientAddr.sin_port));
}

int Run(TrackerContext* ctx) {
  WSADATA wsaData;
  WORD wVersionRequested = MAKEWORD(2, 2);
  int err;
  err = WSAStartup(wVersionRequested, &wsaData);
  if (err != 0) {
    printf("WSAStartup failed with error: %d\n", err);
    return 1;
  }
  if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2) {
    printf("Could not find a usable version of Winsock.dll\n");
    WSACleanup();
    return 1;
  }
  SOCKET serverSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  if (serverSocket == INVALID_SOCKET) {
    printf("socket creation failed with error: %d\n", WSAGetLastError());
    WSACleanup();
    return 1;
  }
  SOCKADDR_IN serverAddr;
  serverAddr.sin_family = AF_INET;
  serverAddr.sin_addr.s_addr = INADDR_ANY;
  serverAddr.sin_port = htons(6969);

  if (bind(serverSocket, (LPSOCKADDR)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
    printf("bind failed with error: %d\n", WSAGetLastError());
    closesocket(serverSocket);
    WSACleanup();
    return 1;
  }

  printf("UDP server is listening on port 6969\n");

  char buf[1500];
  SOCKADDR_IN clientAddr;
  int addrLen = sizeof(clientAddr);

  int txLen, recvLen;
  while (1) {
    recvLen = recvfrom(serverSocket, buf, sizeof(buf), 0, (LPSOCKADDR)&clientAddr, &addrLen);
    if (recvLen == SOCKET_ERROR) {
      printf("recvfrom failed with error: %d\n", WSAGetLastError());
      break;
    }
    PrintClientHostnameAndPort(clientAddr);
    HandleClientRequestV4(ctx, clientAddr.sin_addr.s_addr, buf, recvLen, buf, &txLen);
    if (txLen != -1) {
      sendto(serverSocket, buf, txLen, 0, (LPSOCKADDR)&clientAddr, addrLen);
    }
  }
  closesocket(serverSocket);
  WSACleanup();
}

int main() {
  uint32_t NUM_OF_SUPPORT_PEERS = 16384;
  uint32_t NUM_OF_SUPPORT_TORRENTS = 16384;

  TrackerContextConfig cfg = {
    .announceInterval = 15 * 60,
    .numOfSupportPeers = NUM_OF_SUPPORT_PEERS,
    .numOfSupportTorrents = NUM_OF_SUPPORT_TORRENTS,
  };

  printf("Non-intelligent BitTorrent tracker server\n");
  TrackerContext* ctx = CreateTrackerServer(&cfg);
  if (ctx) { Run(ctx); DeinitTrackerServer(ctx); }
  else { printf("Create tracker server is failure.\n"); }
  return 0;
}