diff options
Diffstat (limited to 'src/connections.cc')
| -rw-r--r-- | src/connections.cc | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/src/connections.cc b/src/connections.cc new file mode 100644 index 0000000..5fd885f --- /dev/null +++ b/src/connections.cc @@ -0,0 +1,554 @@ +#include "login.hh" + +// TODO(fusion): Support windows eventually? +#if OS_LINUX +# include <errno.h> +# include <fcntl.h> +# include <netinet/in.h> +# include <poll.h> +# include <sys/socket.h> +# include <unistd.h> +# include <time.h> +#else +# error "Operating system not currently supported." +#endif + +static const int TERMINALVERSION[] = {770, 770, 770}; +static RSAKey *g_PrivateKey = NULL; +static int g_Listener = -1; +static TConnection *g_Connections = NULL; + +// Connection Handling +//============================================================================== +// NOTE(fusion): This is very similar to the connection handling code used by the +// query manager with a few subtle differences including the encryption scheme. +int ListenerBind(uint16 Port){ + int Socket = socket(AF_INET, SOCK_STREAM, 0); + if(Socket == -1){ + LOG_ERR("Failed to create listener socket: (%d) %s", errno, strerrordesc_np(errno)); + return -1; + } + + int ReuseAddr = 1; + if(setsockopt(Socket, SOL_SOCKET, SO_REUSEADDR, &ReuseAddr, sizeof(ReuseAddr)) == -1){ + LOG_ERR("Failed to set SO_REUSADDR: (%d) %s", errno, strerrordesc_np(errno)); + close(Socket); + return -1; + } + + int Flags = fcntl(Socket, F_GETFL); + if(Flags == -1){ + LOG_ERR("Failed to get socket flags: (%d) %s", errno, strerrordesc_np(errno)); + close(Socket); + return -1; + } + + if(fcntl(Socket, F_SETFL, Flags | O_NONBLOCK) == -1){ + LOG_ERR("Failed to set socket flags: (%d) %s", errno, strerrordesc_np(errno)); + close(Socket); + return -1; + } + + sockaddr_in Addr = {}; + Addr.sin_family = AF_INET; + Addr.sin_port = htons(Port); + Addr.sin_addr.s_addr = htonl(INADDR_ANY); + if(bind(Socket, (sockaddr*)&Addr, sizeof(Addr)) == -1){ + LOG_ERR("Failed to bind socket to port %d: (%d) %s", Port, errno, strerrordesc_np(errno)); + close(Socket); + return -1; + } + + if(listen(Socket, 128) == -1){ + LOG_ERR("Failed to listen to port %d: (%d) %s", Port, errno, strerrordesc_np(errno)); + close(Socket); + return -1; + } + + return Socket; +} + +int ListenerAccept(int Listener, uint32 *OutAddr, uint16 *OutPort){ + while(true){ + sockaddr_in SocketAddr = {}; + socklen_t SocketAddrLen = sizeof(SocketAddr); + int Socket = accept(Listener, (sockaddr*)&SocketAddr, &SocketAddrLen); + if(Socket == -1){ + if(errno != EAGAIN){ + LOG_ERR("Failed to accept connection: (%d) %s", errno, strerrordesc_np(errno)); + } + return -1; + } + + int Flags = fcntl(Socket, F_GETFL); + if(Flags == -1){ + LOG_ERR("Failed to get socket flags: (%d) %s", errno, strerrordesc_np(errno)); + close(Socket); + continue; + } + + if(fcntl(Socket, F_SETFL, Flags | O_NONBLOCK) == -1){ + LOG_ERR("Failed to set socket flags: (%d) %s", errno, strerrordesc_np(errno)); + close(Socket); + continue; + } + + if(OutAddr){ + *OutAddr = ntohl(SocketAddr.sin_addr.s_addr); + } + + if(OutPort){ + *OutPort = ntohs(SocketAddr.sin_port); + } + + return Socket; + } +} + +void CloseConnection(TConnection *Connection){ + if(Connection->Socket != -1){ + close(Connection->Socket); + Connection->Socket = -1; + } +} + +TConnection *AssignConnection(int Socket, uint32 Addr, uint16 Port){ + int ConnectionIndex = -1; + for(int i = 0; i < g_MaxConnections; i += 1){ + if(g_Connections[i].State == CONNECTION_FREE){ + ConnectionIndex = i; + break; + } + } + + TConnection *Connection = NULL; + if(ConnectionIndex != -1){ + Connection = &g_Connections[ConnectionIndex]; + Connection->State = CONNECTION_HANDSHAKE; + Connection->Socket = Socket; + Connection->StartTime = g_MonotonicTimeMS; + Connection->RandomSeed = (uint32)rand(); + snprintf(Connection->IPAddress, sizeof(Connection->IPAddress), + "%d.%d.%d.%d", ((int)(Addr >> 24) & 0xFF), ((int)(Addr >> 16) & 0xFF), + ((int)(Addr >> 8) & 0xFF), ((int)(Addr >> 0) & 0xFF)); + snprintf(Connection->RemoteAddress, sizeof(Connection->RemoteAddress), + "%s:%d", Connection->IPAddress, (int)Port); + LOG("Connection %s assigned to slot %d", + Connection->RemoteAddress, ConnectionIndex); + } + return Connection; +} + +void ReleaseConnection(TConnection *Connection){ + if(Connection->State != CONNECTION_FREE){ + LOG("Connection %s released", Connection->RemoteAddress); + CloseConnection(Connection); + memset(Connection, 0, sizeof(TConnection)); + Connection->State = CONNECTION_FREE; + } +} + +void CheckConnectionInput(TConnection *Connection, int Events){ + if((Events & POLLIN) == 0 || Connection->Socket == -1){ + return; + } + + if(Connection->State != CONNECTION_HANDSHAKE){ + LOG_ERR("Connection %s (State: %d) sending out-of-order data", + Connection->RemoteAddress, Connection->State); + CloseConnection(Connection); + return; + } + + while(true){ + int ReadSize = Connection->RWSize; + if(ReadSize == 0){ + ReadSize = 2 - Connection->RWPosition; + ASSERT(ReadSize > 0); + } + + int BytesRead = read(Connection->Socket, + (Connection->Buffer + Connection->RWPosition), + (ReadSize - Connection->RWPosition)); + if(BytesRead == -1){ + if(errno != EAGAIN){ + // NOTE(fusion): Connection error. + CloseConnection(Connection); + } + break; + }else if(BytesRead == 0){ + // NOTE(fusion): Graceful close. + CloseConnection(Connection); + break; + } + + Connection->RWPosition += BytesRead; + if(Connection->RWPosition >= ReadSize){ + if(Connection->RWSize == 0){ + int PayloadSize = BufferRead16LE(Connection->Buffer); + if(PayloadSize <= 0 || PayloadSize > NARRAY(Connection->Buffer)){ + CloseConnection(Connection); + break; + } + + Connection->RWSize = PayloadSize; + Connection->RWPosition = 0; + }else{ + Connection->State = CONNECTION_LOGIN; + break; + } + } + } + + if(Connection->State == CONNECTION_LOGIN){ + ProcessLoginRequest(Connection); + } +} + +void CheckConnectionOutput(TConnection *Connection, int Events){ + if((Events & POLLOUT) == 0 || Connection->Socket == -1){ + return; + } + + if(Connection->State != CONNECTION_WRITE){ + return; + } + + while(true){ + int BytesWritten = write(Connection->Socket, + (Connection->Buffer + Connection->RWPosition), + (Connection->RWSize - Connection->RWPosition)); + if(BytesWritten == -1){ + if(errno != EAGAIN){ + CloseConnection(Connection); + } + break; + } + + Connection->RWPosition += BytesWritten; + if(Connection->RWPosition >= Connection->RWSize){ + CloseConnection(Connection); + break; + } + } +} + +void CheckConnection(TConnection *Connection, int Events){ + ASSERT((Events & POLLNVAL) == 0); + + if((Events & (POLLERR | POLLHUP)) != 0){ + CloseConnection(Connection); + } + + if(g_LoginTimeout > 0){ + int LoginTime = (g_MonotonicTimeMS - Connection->StartTime); + if(LoginTime >= g_LoginTimeout){ + LOG_WARN("Connection %s TIMEDOUT (LoginTime: %dms, Timeout: %dms)", + Connection->RemoteAddress, LoginTime, g_LoginTimeout); + CloseConnection(Connection); + } + } + + if(Connection->Socket == -1){ + ReleaseConnection(Connection); + } +} + +void ProcessConnections(void){ + // NOTE(fusion): Accept new connections. + while(true){ + uint32 Addr; + uint16 Port; + int Socket = ListenerAccept(g_Listener, &Addr, &Port); + if(Socket == -1){ + break; + } + + if(AssignConnection(Socket, Addr, Port) == NULL){ + LOG_ERR("Rejecting connection from %08X due to max number of" + " connections being reached (%d)", Addr, g_MaxConnections); + close(Socket); + } + } + + // NOTE(fusion): Gather active connections. + int NumConnections = 0; + int *ConnectionIndices = (int*)alloca(g_MaxConnections * sizeof(int)); + pollfd *ConnectionFds = (pollfd*)alloca(g_MaxConnections * sizeof(pollfd)); + for(int i = 0; i < g_MaxConnections; i += 1){ + if(g_Connections[i].State == CONNECTION_FREE || g_Connections[i].Socket == -1){ + continue; + } + + ConnectionIndices[NumConnections] = i; + ConnectionFds[NumConnections].fd = g_Connections[i].Socket; + ConnectionFds[NumConnections].events = POLLIN | POLLOUT; + ConnectionFds[NumConnections].revents = 0; + NumConnections += 1; + } + + if(NumConnections <= 0){ + return; + } + + // NOTE(fusion): Poll connections. + int NumEvents = poll(ConnectionFds, NumConnections, 0); + if(NumEvents == -1){ + LOG_ERR("Failed to poll connections: (%d) %s", errno, strerrordesc_np(errno)); + return; + } + + // NOTE(fusion): Process connections. + for(int i = 0; i < NumConnections; i += 1){ + TConnection *Connection = &g_Connections[ConnectionIndices[i]]; + int Events = (int)ConnectionFds[i].revents; + CheckConnectionInput(Connection, Events); + CheckConnectionOutput(Connection, Events); + CheckConnection(Connection, Events); + } +} + +bool InitConnections(void){ + ASSERT(g_Listener == -1); + ASSERT(g_Connections == NULL); + + LOG("Login port: %d", g_LoginPort); + LOG("Max connections: %d", g_MaxConnections); + LOG("Login timeout: %dms", g_LoginTimeout); + + g_PrivateKey = RSALoadPEM("tibia.pem"); + if(g_PrivateKey == NULL){ + LOG_ERR("Failed to load RSA key"); + return false; + } + + g_Listener = ListenerBind(g_LoginPort); + if(g_Listener == -1){ + LOG_ERR("Failed to bind listener"); + return false; + } + + g_Connections = (TConnection*)calloc(g_MaxConnections, sizeof(TConnection)); + for(int i = 0; i < g_MaxConnections; i += 1){ + g_Connections[i].State = CONNECTION_FREE; + } + + return true; +} + +void ExitConnections(void){ + if(g_PrivateKey != NULL){ + RSAFree(g_PrivateKey); + g_PrivateKey = NULL; + } + + if(g_Listener != -1){ + close(g_Listener); + g_Listener = -1; + } + + if(g_Connections != NULL){ + for(int i = 0; i < g_MaxConnections; i += 1){ + ReleaseConnection(&g_Connections[i]); + } + + free(g_Connections); + g_Connections = NULL; + } +} + +// Connection Requests +//============================================================================== +TWriteBuffer PrepareResponse(TConnection *Connection){ + if(Connection->State != CONNECTION_LOGIN){ + LOG_ERR("Connection %s is not processing login (State: %d)", + Connection->RemoteAddress, Connection->State); + CloseConnection(Connection); + return TWriteBuffer(NULL, 0); + } + + TWriteBuffer WriteBuffer(Connection->Buffer, sizeof(Connection->Buffer)); + WriteBuffer.Write16(0); // Encrypted Size + WriteBuffer.Write16(0); // Data Size + return WriteBuffer; +} + +void SendResponse(TConnection *Connection, TWriteBuffer *WriteBuffer){ + if(Connection->State != CONNECTION_LOGIN){ + LOG_ERR("Connection %s is not processing login (State: %d)", + Connection->RemoteAddress, Connection->State); + CloseConnection(Connection); + return; + } + + ASSERT(WriteBuffer != NULL + && WriteBuffer->Buffer == Connection->Buffer + && WriteBuffer->Size == sizeof(Connection->Buffer) + && WriteBuffer->Position > 4); + + int DataSize = WriteBuffer->Position - 4; + int EncryptedSize = WriteBuffer->Position - 2; + while((EncryptedSize % 8) != 0){ + WriteBuffer->Write8(rand_r(&Connection->RandomSeed)); + EncryptedSize += 1; + } + + if(WriteBuffer->Overflowed()){ + LOG_ERR("Write buffer overflowed when writing response to %s", + Connection->RemoteAddress); + CloseConnection(Connection); + return; + } + + WriteBuffer->Rewrite16(0, EncryptedSize); + WriteBuffer->Rewrite16(2, DataSize); + XTEAEncrypt(Connection->XTEA, + WriteBuffer->Buffer + 2, + WriteBuffer->Position - 2); + Connection->State = CONNECTION_WRITE; + Connection->RWSize = WriteBuffer->Position; + Connection->RWPosition = 0; +} + +void SendLoginError(TConnection *Connection, const char *Message){ + TWriteBuffer WriteBuffer = PrepareResponse(Connection); + WriteBuffer.Write8(10); // LOGIN_ERROR + WriteBuffer.WriteString(Message); + SendResponse(Connection, &WriteBuffer); +} + +void SendCharacterList(TConnection *Connection, int NumCharacters, + TCharacterLoginData *Characters, int PremiumDays){ + TWriteBuffer WriteBuffer = PrepareResponse(Connection); + + if(g_Motd[0] != 0){ + WriteBuffer.Write8(20); // MOTD + WriteBuffer.WriteString(g_Motd); + } + + WriteBuffer.Write8(100); // CHARACTER_LIST + if(NumCharacters > UINT8_MAX){ + NumCharacters = UINT8_MAX; + } + WriteBuffer.Write8(NumCharacters); + for(int i = 0; i < NumCharacters; i += 1){ + WriteBuffer.WriteString(Characters[i].Name); + WriteBuffer.WriteString(Characters[i].WorldName); + WriteBuffer.Write32BE((uint32)Characters[i].WorldAddress); + WriteBuffer.Write16((uint16)Characters[i].WorldPort); + } + WriteBuffer.Write16((uint16)PremiumDays); + + SendResponse(Connection, &WriteBuffer); +} + +void ProcessLoginRequest(TConnection *Connection){ + if(Connection->RWSize != 145){ + LOG_ERR("Invalid login request size %d from %s (expected 145)", + Connection->RWSize, Connection->RemoteAddress); + CloseConnection(Connection); + return; + } + + TReadBuffer InputBuffer(Connection->Buffer, Connection->RWSize); + int Command = InputBuffer.Read8(); + if(Command != 1){ + LOG_ERR("Invalid login command %d from %s (expected 1)", + Command, Connection->RemoteAddress); + CloseConnection(Connection); + return; + } + + int TerminalType = InputBuffer.Read16(); + int TerminalVersion = InputBuffer.Read16(); + InputBuffer.Read32(); // DATSIGNATURE + InputBuffer.Read32(); // SPRSIGNATURE + InputBuffer.Read32(); // PICSIGNATURE + + uint8 AsymmetricData[128]; + InputBuffer.ReadBytes(AsymmetricData, sizeof(AsymmetricData)); + if(InputBuffer.Overflowed()){ + LOG_ERR("Input buffer overflowed while reading login command from %s", + Connection->RemoteAddress); + CloseConnection(Connection); + return; + } + + if(!RSADecrypt(g_PrivateKey, AsymmetricData, sizeof(AsymmetricData))){ + LOG_ERR("Failed to decrypt asymmetric data from %s", + Connection->RemoteAddress); + CloseConnection(Connection); + return; + } + + TReadBuffer Buffer(AsymmetricData, sizeof(AsymmetricData)); + Buffer.Read8(); // always zero + Connection->XTEA[0] = Buffer.Read32(); + Connection->XTEA[1] = Buffer.Read32(); + Connection->XTEA[2] = Buffer.Read32(); + Connection->XTEA[3] = Buffer.Read32(); + + if(TerminalType < 0 || TerminalType >= NARRAY(TERMINALVERSION) + || TERMINALVERSION[TerminalType] != TerminalVersion){ + SendLoginError(Connection, + "Your terminal version is too old.\n" + "Please get a new version at\n" + "http://www.tibia.com."); + return; + } + + char Password[30]; + int AccountID = Buffer.Read32(); + Buffer.ReadString(Password, sizeof(Password)); + if(Buffer.Overflowed()){ + LOG_ERR("Malformed asymmetric data from %s", Connection->RemoteAddress); + CloseConnection(Connection); + return; + } + + int NumCharacters = 0; + int PremiumDays = 0; + TCharacterLoginData Characters[50]; + int LoginCode = LoginAccount(AccountID, Password, Connection->IPAddress, + NARRAY(Characters), &NumCharacters, Characters, &PremiumDays); + switch(LoginCode){ + case 0:{ + SendCharacterList(Connection, NumCharacters, Characters, PremiumDays); + break; + } + + case 1: // Invalid account number + case 2:{ // Invalid password + SendLoginError(Connection, "Accountnumber or password is not correct."); + break; + } + + case 3:{ + SendLoginError(Connection, "Account disabled for five minutes. Please wait."); + break; + } + + case 4:{ + SendLoginError(Connection, "IP address blocked for 30 minutes. Please wait."); + break; + } + + case 5:{ + SendLoginError(Connection, "Your account is banished."); + break; + } + + case 6:{ + SendLoginError(Connection, "Your IP address is banished."); + break; + } + + default:{ + if(LoginCode != -1){ + LOG_ERR("Invalid login code %d", LoginCode); + } + SendLoginError(Connection, "Internal error, closing connection."); + break; + } + } +} |