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direwolf/kissnet.c

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//
// 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 <http://www.gnu.org/licenses/>.
//
/*------------------------------------------------------------------
*
* 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* Spec says it is obsolete but Xastir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 <winsock2.h>
#include <ws2tcpip.h> // _WIN32_WINNT must be set to 0x0501 before including this
#else
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#ifdef __OpenBSD__
#include <errno.h>
#else
#include <sys/errno.h>
#endif
#endif
#include <unistd.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#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; client<MAX_NET_CLIENTS; client++) {
client_sock[client] = -1;
memset (&(kf[client]), 0, sizeof(kf[client]));
}
if (kiss_port == 0) {
text_color_set(DW_COLOR_INFO);
dw_printf ("Disabled KISS network client port.\n");
return;
}
/*
* This waits for a client to connect and sets client_sock[n].
*/
#if __WIN32__
connect_listen_th = (HANDLE)_beginthreadex (NULL, 0, connect_listen_thread, (void *)kiss_port, 0, NULL);
if (connect_listen_th == NULL) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Could not create KISS socket connect listening thread\n");
return;
}
#else
e = pthread_create (&connect_listen_tid, NULL, connect_listen_thread, (void *)(long)kiss_port);
if (e != 0) {
text_color_set(DW_COLOR_ERROR);
perror("Could not create KISS socket connect listening thread");
return;
}
#endif
/*
* These read messages from client when client_sock[n] is valid.
* Currently we start up a separate thread for each potential connection.
* Possible later refinement. Start one now, others only as needed.
*/
for (client = 0; client < MAX_NET_CLIENTS; client++) {
#if __WIN32__
cmd_listen_th[client] = (HANDLE)_beginthreadex (NULL, 0, kissnet_listen_thread, (void*)client, 0, NULL);
if (cmd_listen_th[client] == NULL) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Could not create KISS socket command listening thread\n");
return;
}
#else
e = pthread_create (&(cmd_listen_tid[client]), NULL, kissnet_listen_thread, NULL);
if (e != 0) {
text_color_set(DW_COLOR_ERROR);
perror("Could not create KISS socket command listening thread");
return;
}
#endif
}
}
/*-------------------------------------------------------------------
*
* Name: connect_listen_thread
*
* Purpose: Wait for a connection request from an application.
*
* Inputs: arg - TCP port for server.
* Main program has default of 8001 but allows
* an alternative to be specified on the command line
*
* Outputs: client_sock - File descriptor for communicating with client app.
*
* Description: Wait for connection request from client and establish
* communication.
* Note that the client can go away and come back again and
* re-establish communication without restarting this application.
*
*--------------------------------------------------------------------*/
static THREAD_F connect_listen_thread (void *arg)
{
#if __WIN32__
struct addrinfo hints;
struct addrinfo *ai = NULL;
int err;
char kiss_port_str[12];
SOCKET listen_sock;
WSADATA wsadata;
snprintf (kiss_port_str, sizeof(kiss_port_str), "%d", (int)(long)arg);
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("DEBUG: kissnet port = %d = '%s'\n", (int)(long)arg, kiss_port_str);
#endif
err = WSAStartup (MAKEWORD(2,2), &wsadata);
if (err != 0) {
text_color_set(DW_COLOR_ERROR);
dw_printf("WSAStartup failed: %d\n", err);
return (0);
}
if (LOBYTE(wsadata.wVersion) != 2 || HIBYTE(wsadata.wVersion) != 2) {
text_color_set(DW_COLOR_ERROR);
dw_printf("Could not find a usable version of Winsock.dll\n");
WSACleanup();
//sleep (1);
return (0);
}
memset (&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
err = getaddrinfo(NULL, kiss_port_str, &hints, &ai);
if (err != 0) {
text_color_set(DW_COLOR_ERROR);
dw_printf("getaddrinfo failed: %d\n", err);
//sleep (1);
WSACleanup();
return (0);
}
listen_sock= socket(ai->ai_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 */
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