// // This file is part of Dire Wolf, an amateur radio packet TNC. // // Copyright (C) 2011-2014, 2015, 2017 John Langner, WB2OSZ // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 2 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program. If not, see . // /*------------------------------------------------------------------ * * Module: kissnet.c * * Purpose: Provide service to other applications via KISS protocol via TCP socket. * * Input: * * Outputs: * * Description: This provides a TCP socket for communication with a client application. * * It implements the KISS TNS protocol as described in: * http://www.ka9q.net/papers/kiss.html * * Briefly, a frame is composed of * * * FEND (0xC0) * * Contents - with special escape sequences so a 0xc0 * byte in the data is not taken as end of frame. * as part of the data. * * FEND * * The first byte of the frame contains: * * * port number in upper nybble. * * command in lower nybble. * * * Commands from application recognized: * * _0 Data Frame AX.25 frame in raw format. * * _1 TXDELAY See explanation in xmit.c. * * _2 Persistence " " * * _3 SlotTime " " * * _4 TXtail " " * Spec says it is obsolete but Xastir * sends it and we respect it. * * _5 FullDuplex Ignored. * * _6 SetHardware TNC specific. * * FF Return Exit KISS mode. Ignored. * * * Messages sent to client application: * * _0 Data Frame Received AX.25 frame in raw format. * * * * * References: Getting Started with Winsock * http://msdn.microsoft.com/en-us/library/windows/desktop/bb530742(v=vs.85).aspx * * Future: Originally we had: * KISS over serial port. * AGW over socket. * This is the two of them munged together and we end up with duplicate code. * It would have been better to separate out the transport and application layers. * Maybe someday. * *---------------------------------------------------------------*/ /* * Native Windows: Use the Winsock interface. * Linux: Use the BSD socket interface. */ #include "direwolf.h" // Sets _WIN32_WINNT for XP API level needed by ws2tcpip.h #if __WIN32__ #include #include // _WIN32_WINNT must be set to 0x0501 before including this #else #include #include #include #include #include #ifdef __OpenBSD__ #include #else #include #endif #endif #include #include #include #include #include "tq.h" #include "ax25_pad.h" #include "textcolor.h" #include "audio.h" #include "kissnet.h" #include "kiss_frame.h" #include "xmit.h" void hex_dump (unsigned char *p, int len); // This should be in a .h file. /* * Early on we allowed one AGW connection and one KISS TCP connection at a time. * In version 1.1, we allowed multiple concurrent client apps to attach with the AGW network protocol. * In Version 1.5, we do essentially the same here to allow multiple concurrent KISS TCP clients. * The default is a limit of 3 client applications at the same time. * You can increase the limit by changing the line below. * A larger number consumes more resources so don't go crazy by making it larger than needed. */ #define MAX_NET_CLIENTS 3 static int client_sock[MAX_NET_CLIENTS]; /* File descriptor for socket for */ /* communication with client application. */ /* Set to -1 if not connected. */ /* (Don't use SOCKET type because it is unsigned.) */ static kiss_frame_t kf[MAX_NET_CLIENTS]; /* Accumulated KISS frame and state of decoder. */ // TODO: define in one place, use everywhere. #if __WIN32__ #define THREAD_F unsigned __stdcall #else #define THREAD_F void * #endif static THREAD_F connect_listen_thread (void *arg); static THREAD_F kissnet_listen_thread (void *arg); static int kiss_debug = 0; /* Print information flowing from and to client. */ void kiss_net_set_debug (int n) { kiss_debug = n; } /*------------------------------------------------------------------- * * Name: kissnet_init * * Purpose: Set up a server to listen for connection requests from * an application such as Xastir or APRSIS32. * * Inputs: mc->kiss_port - TCP port for server. * Main program has default of 8000 but allows * an alternative to be specified on the command line * * 0 means disable. New in version 1.2. * * Outputs: * * Description: This starts two threads: * * to listen for a connection from client app. * * to listen for commands from client app. * so the main application doesn't block while we wait for these. * *--------------------------------------------------------------------*/ void kissnet_init (struct misc_config_s *mc) { int client; #if __WIN32__ HANDLE connect_listen_th; HANDLE cmd_listen_th[MAX_NET_CLIENTS]; #else pthread_t connect_listen_tid; pthread_t cmd_listen_tid[MAX_NET_CLIENTS]; int e; #endif int kiss_port = mc->kiss_port; #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("kissnet_init ( %d )\n", kiss_port); #endif for (client=0; clientai_family, ai->ai_socktype, ai->ai_protocol); if (listen_sock == INVALID_SOCKET) { text_color_set(DW_COLOR_ERROR); dw_printf ("connect_listen_thread: Socket creation failed, err=%d", WSAGetLastError()); return (0); } #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf("Binding to port %s ... \n", kiss_port_str); #endif err = bind( listen_sock, ai->ai_addr, (int)ai->ai_addrlen); if (err == SOCKET_ERROR) { text_color_set(DW_COLOR_ERROR); dw_printf("Bind failed with error: %d\n", WSAGetLastError()); // TODO: provide corresponding text. dw_printf("Some other application is probably already using port %s.\n", kiss_port_str); dw_printf("Try using a different port number with KISSPORT in the configuration file.\n"); freeaddrinfo(ai); closesocket(listen_sock); WSACleanup(); return (0); } freeaddrinfo(ai); #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf("opened KISS socket as fd (%d) on port (%s) for stream i/o\n", listen_sock, kiss_port_str ); #endif while (1) { int client; int c; client = -1; for (c = 0; c < MAX_NET_CLIENTS && client < 0; c++) { if (client_sock[c] <= 0) { client = c; } } /* * Listen for connection if we have not reached maximum. */ if (client >= 0) { if(listen(listen_sock, MAX_NET_CLIENTS) == SOCKET_ERROR) { text_color_set(DW_COLOR_ERROR); dw_printf("Listen failed with error: %d\n", WSAGetLastError()); return (0); } text_color_set(DW_COLOR_INFO); dw_printf("Ready to accept KISS TCP client application %d on port %s ...\n", client, kiss_port_str); client_sock[client] = accept(listen_sock, NULL, NULL); if (client_sock[client] == -1) { text_color_set(DW_COLOR_ERROR); dw_printf("Accept failed with error: %d\n", WSAGetLastError()); closesocket(listen_sock); WSACleanup(); return (0); } text_color_set(DW_COLOR_INFO); dw_printf("\nAttached to KISS TCP client application %d ...\n\n", client); // Reset the state and buffer. memset (&(kf[client]), 0, sizeof(kf[client])); } else { SLEEP_SEC(1); /* wait then check again if more clients allowed. */ } } #else /* End of Windows case, now Linux. */ struct sockaddr_in sockaddr; /* Internet socket address stuct */ socklen_t sockaddr_size = sizeof(struct sockaddr_in); int kiss_port = (int)(long)arg; int listen_sock; int bcopt = 1; listen_sock= socket(AF_INET,SOCK_STREAM,0); if (listen_sock == -1) { text_color_set(DW_COLOR_ERROR); perror ("connect_listen_thread: Socket creation failed"); return (NULL); } /* Version 1.3 - as suggested by G8BPQ. */ /* Without this, if you kill the application then try to run it */ /* again quickly the port number is unavailable for a while. */ /* Don't try doing the same thing On Windows; It has a different meaning. */ /* http://stackoverflow.com/questions/14388706/socket-options-so-reuseaddr-and-so-reuseport-how-do-they-differ-do-they-mean-t */ setsockopt (listen_sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&bcopt, 4); sockaddr.sin_addr.s_addr = INADDR_ANY; sockaddr.sin_port = htons(kiss_port); sockaddr.sin_family = AF_INET; #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf("Binding to port %d ... \n", kiss_port); #endif if (bind(listen_sock,(struct sockaddr*)&sockaddr,sizeof(sockaddr)) == -1) { text_color_set(DW_COLOR_ERROR); dw_printf("Bind failed with error: %d\n", errno); dw_printf("%s\n", strerror(errno)); dw_printf("Some other application is probably already using port %d.\n", kiss_port); dw_printf("Try using a different port number with KISSPORT in the configuration file.\n"); return (NULL); } getsockname( listen_sock, (struct sockaddr *)(&sockaddr), &sockaddr_size); #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf("opened KISS TCP socket as fd (%d) on port (%d) for stream i/o\n", listen_sock, ntohs(sockaddr.sin_port) ); #endif while (1) { int client; int c; client = -1; for (c = 0; c < MAX_NET_CLIENTS && client < 0; c++) { if (client_sock[c] <= 0) { client = c; } } if (client >= 0) { if(listen(listen_sock,MAX_NET_CLIENTS) == -1) { text_color_set(DW_COLOR_ERROR); perror ("connect_listen_thread: Listen failed"); return (NULL); } text_color_set(DW_COLOR_INFO); dw_printf("Ready to accept KISS TCP client application %d on port %d ...\n", client, kiss_port); client_sock[client] = accept(listen_sock, (struct sockaddr*)(&sockaddr),&sockaddr_size); text_color_set(DW_COLOR_INFO); dw_printf("\nAttached to KISS TCP client application %d...\n\n", client); // Reset the state and buffer. memset (&(kf[client]), 0, sizeof(kf[client])); } else { SLEEP_SEC(1); /* wait then check again if more clients allowed. */ } } #endif } /*------------------------------------------------------------------- * * Name: kissnet_send_rec_packet * * Purpose: Send a received packet to the client app. * * Inputs: chan - Channel number where packet was received. * 0 = first, 1 = second if any. * // TODO: add kiss_cmd * * fbuf - Address of raw received frame buffer * or a text string. * * kiss_cmd - Usually KISS_CMD_DATA_FRAME but we can also have * KISS_CMD_SET_HARDWARE when responding to a query. * * flen - Number of bytes for AX.25 frame. * When called from kiss_rec_byte, flen will be -1 * indicating a text string rather than frame content. * This is used to fake out an application that thinks * it is using a traditional TNC and tries to put it * into KISS mode. * * tcpclient - It is possible to have more than client attached * at the same time with TCP KISS. * When a frame is received from the radio we want it * to go to all of the clients. In this case specify -1. * When responding to a command from the client, we want * to send only to that one client app. In this case * use the value 0 .. MAX_NET_CLIENTS-1. * * Description: Send message to client(s) if connected. * Disconnect from client, and notify user, if any error. * *--------------------------------------------------------------------*/ void kissnet_send_rec_packet (int chan, int kiss_cmd, unsigned char *fbuf, int flen, int tcpclient) { unsigned char kiss_buff[2 * AX25_MAX_PACKET_LEN]; int kiss_len; int err; int first, last, client; // Something received over the radio would be sent to all attached clients. // However, there are times we want to send a response only to a particular client. // In the case of a serial port or pseudo terminal, there is only one potential client. // so the response would be sent to only one place. A new parameter has been added for this. if (tcpclient >= 0 && tcpclient < MAX_NET_CLIENTS) { first = tcpclient; last = tcpclient; } else if (tcpclient == -1) { first = 0; last = MAX_NET_CLIENTS - 1; } else { text_color_set(DW_COLOR_ERROR); dw_printf ("KISS TCP: Internal error, kissnet_send_rec_packet, tcpclient = %d.\n", tcpclient); return; } for (client = first; client <= last; client++) { if (client_sock[client] != -1) { if (flen < 0) { // A client app might think it is attached to a traditional TNC. // It might try sending commands over and over again trying to get the TNC into KISS mode. // We recognize this attempt and send it something to keep it happy. text_color_set(DW_COLOR_ERROR); dw_printf ("KISS TCP: Something unexpected from client application.\n"); dw_printf ("Is client app treating this like an old TNC with command mode?\n"); flen = strlen((char*)fbuf); if (kiss_debug) { kiss_debug_print (TO_CLIENT, "Fake command prompt", fbuf, flen); } strlcpy ((char *)kiss_buff, (char *)fbuf, sizeof(kiss_buff)); kiss_len = strlen((char *)kiss_buff); } else { unsigned char stemp[AX25_MAX_PACKET_LEN + 1]; assert (flen < (int)(sizeof(stemp))); stemp[0] = (chan << 4) | kiss_cmd; memcpy (stemp+1, fbuf, flen); if (kiss_debug >= 2) { /* AX.25 frame with the CRC removed. */ text_color_set(DW_COLOR_DEBUG); dw_printf ("\n"); dw_printf ("Packet content before adding KISS framing and any escapes:\n"); hex_dump (fbuf, flen); } kiss_len = kiss_encapsulate (stemp, flen+1, kiss_buff); /* This has the escapes and the surrounding FENDs. */ if (kiss_debug) { kiss_debug_print (TO_CLIENT, NULL, kiss_buff, kiss_len); } } #if __WIN32__ err = send (client_sock[client], (char*)kiss_buff, kiss_len, 0); if (err == SOCKET_ERROR) { text_color_set(DW_COLOR_ERROR); dw_printf ("\nError %d sending message to KISS client application. Closing connection.\n\n", WSAGetLastError()); closesocket (client_sock[client]); client_sock[client] = -1; WSACleanup(); } #else err = write (client_sock[client], kiss_buff, kiss_len); if (err <= 0) { text_color_set(DW_COLOR_ERROR); dw_printf ("\nError sending message to KISS client application. Closing connection.\n\n"); close (client_sock[client]); client_sock[client] = -1; } #endif } } } /* end kissnet_send_rec_packet */ /*------------------------------------------------------------------- * * Name: read_from_socket * * Purpose: Read from socket until we have desired number of bytes. * * Inputs: fd - file descriptor. * ptr - address where data should be placed. * len - desired number of bytes. * * Description: Just a wrapper for the "read" system call but it should * never return fewer than the desired number of bytes. * * Not really needed for KISS because we are dealing with * a stream of bytes rather than message blocks. * *--------------------------------------------------------------------*/ static int read_from_socket (int fd, char *ptr, int len) { int got_bytes = 0; #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("read_from_socket (%d, %p, %d)\n", fd, ptr, len); #endif while (got_bytes < len) { int n; #if __WIN32__ n = recv (fd, ptr + got_bytes, len - got_bytes, 0); #else n = read (fd, ptr + got_bytes, len - got_bytes); #endif //Would be useful to have more detailed explanation from the error code. #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("read_from_socket: n = %d\n", n); #endif if (n <= 0) { return (n); } got_bytes += n; } assert (got_bytes >= 0 && got_bytes <= len); #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("read_from_socket: return %d\n", got_bytes); #endif return (got_bytes); } /*------------------------------------------------------------------- * * Name: kissnet_listen_thread * * Purpose: Wait for KISS messages from an application. * * Inputs: arg - client number, 0 .. MAX_NET_CLIENTS-1 * * Outputs: client_sock[n] - File descriptor for communicating with client app. * * Description: Process messages from the client application. * Note that the client can go away and come back again and * re-establish communication without restarting this application. * *--------------------------------------------------------------------*/ /* Return one byte (value 0 - 255) */ static int kiss_get (int client) { unsigned char ch; int n; while (1) { while (client_sock[client] <= 0) { SLEEP_SEC(1); /* Not connected. Try again later. */ } /* Just get one byte at a time. */ n = read_from_socket (client_sock[client], (char *)(&ch), 1); if (n == 1) { #if DEBUG9 dw_printf (log_fp, "%02x %c %c", ch, isprint(ch) ? ch : '.' , (isupper(ch>>1) || isdigit(ch>>1) || (ch>>1) == ' ') ? (ch>>1) : '.'); if (ch == FEND) fprintf (log_fp, " FEND"); if (ch == FESC) fprintf (log_fp, " FESC"); if (ch == TFEND) fprintf (log_fp, " TFEND"); if (ch == TFESC) fprintf (log_fp, " TFESC"); if (ch == '\r') fprintf (log_fp, " CR"); if (ch == '\n') fprintf (log_fp, " LF"); fprintf (log_fp, "\n"); if (ch == FEND) fflush (log_fp); #endif return(ch); } text_color_set(DW_COLOR_ERROR); dw_printf ("\nError reading KISS byte from client application %d. Closing connection.\n\n", client); #if __WIN32__ closesocket (client_sock[client]); #else close (client_sock[client]); #endif client_sock[client] = -1; } } static THREAD_F kissnet_listen_thread (void *arg) { unsigned char ch; #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("kissnet_listen_thread ( socket = %d )\n", client_sock); #endif int client = (int)(long)arg; assert (client >= 0 && client < MAX_NET_CLIENTS); // So why is kissnet_send_rec_packet mentioned here for incoming from the client app? // The logic exists for the serial port case where the client might think it is // attached to a traditional TNC. It might try sending commands over and over again // trying to get the TNC into KISS mode. To keep it happy, we recognize this attempt // and send it something to keep it happy. // In the case of a serial port or pseudo terminal, there is only one potential client // so the response would be sent to only one place. // Starting in version 1.5, this now can have multiple attached clients. We wouldn't // want to send the response to all of them. Actually, we should be providing only // "Simply KISS" as some call it. while (1) { ch = kiss_get(client); kiss_rec_byte (&(kf[client]), ch, kiss_debug, client, kissnet_send_rec_packet); } #if __WIN32__ return(0); #else return (THREAD_F) 0; /* Unreachable but avoids compiler warning. */ #endif } /* end kissnet_listen_thread */ /* end kissnet.c */