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direwolf/src/appserver.c

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// ****** PRELIMINARY - needs work ******
#define DEBUG 1
//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
#include "direwolf.h"
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <assert.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <getopt.h>
#include "ax25_pad.h"
#include "textcolor.h"
#include "agwlib.h" // Network TNC interface.
/*------------------------------------------------------------------
*
* Module: appserver.c
*
* Purpose: Simple application server for connected mode AX.25.
*
* This demonstrates how you can write a application that will wait for
* a connection from another station and respond to commands.
* It can be used as a starting point for developing your own applications.
*
* Description: This attaches to an instance of Dire Wolf via the AGW network interface.
* It processes commands from other radio stations and responds.
*
*---------------------------------------------------------------*/
static void usage()
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("Usage: \n");
dw_printf (" \n");
dw_printf ("appserver [ -h hostname ] [ -p port ] mycall \n");
dw_printf (" \n");
dw_printf (" -h hostname for TNC. Default is localhost. \n");
dw_printf (" \n");
dw_printf (" -p tcp port for TNC. Default is 8000. \n");
dw_printf (" \n");
dw_printf (" mycall is required because that is the callsign for \n");
dw_printf (" which the TNC will accept connections. \n");
dw_printf (" \n");
exit (EXIT_FAILURE);
}
static char mycall[AX25_MAX_ADDR_LEN]; /* Callsign, with SSID, for the application. */
/* Future? Could have multiple applications, on the same */
/* radio channel, each with its own SSID. */
static char tnc_hostname[80]; /* DNS host name or IPv4 address. */
/* Some of the code is there for IPv6 but */
/* needs more work. */
/* Defaults to "localhost" if not specified. */
static char tnc_port[8]; /* a TCP port number. Default 8000. */
/*
* Maintain information about connections from users which we will call "sessions."
* It should be possible to have multiple users connected at the same time.
*
* This allows a "who" command to see who is currently connected and a place to keep
* possible state information for each user.
*
* Each combination of channel & callsign is a separate session.
* The same user (callsign), on a different channel, is a different session.
*/
struct session_s {
char client_addr[AX25_MAX_ADDR_LEN]; // Callsign of other station.
// Clear to mean this table entry is not in use.
int channel; // Radio channel.
time_t login_time; // Time when connection established.
// For the timing test.
// Send specified number of frames, optional length.
// When finished summarize with statistics.
time_t tt_start_time;
volatile int tt_count; // Number to send.
int tt_length; // Bytes in info part.
int tt_next; // Next sequence to send.
volatile int tx_queue_len; // Number in transmit queue. For flow control.
};
#define MAX_SESSIONS 12
static struct session_s session[MAX_SESSIONS];
static int find_session (int chan, char *addr, int create);
static void poll_timing_test (void);
/*------------------------------------------------------------------
*
* Name: main
*
* Purpose: Attach to Dire Wolf TNC, wait for requests from users.
*
* Usage: Described above.
*
*---------------------------------------------------------------*/
int main (int argc, char *argv[])
{
int c;
char *p;
#if __WIN32__
setvbuf(stdout, NULL, _IONBF, 0);
#else
setlinebuf (stdout);
#endif
memset (session, 0, sizeof(session));
strlcpy (tnc_hostname, "localhost", sizeof(tnc_hostname));
strlcpy (tnc_port, "8000", sizeof(tnc_port));
/*
* Extract command line args.
*/
while ((c = getopt (argc, argv, "h:p:")) != -1) {
switch (c) {
case 'h':
strlcpy (tnc_hostname, optarg, sizeof(tnc_hostname));
break;
case 'p':
strlcpy (tnc_port, optarg, sizeof(tnc_port));
break;
default:
usage ();
}
}
if (argv[optind] == NULL) {
usage ();
}
strlcpy (mycall, argv[optind], sizeof(mycall));
// Force to upper case.
for (p = mycall; *p != '\0'; p++) {
if (islower(*p)) {
*p = toupper(*p);
}
}
/*
* Establish a TCP socket to the network TNC.
* It starts up a thread, which listens for messages from the TNC,
* and calls the corresponding agw_cb_... callback functions.
*
* After attaching to the TNC, the specified init function is called.
* We pass it to the library, rather than doing it here, so it can
* repeated automatically if the TNC goes away and comes back again.
* We need to reestablish what it knows about the application.
*/
if (agwlib_init (tnc_hostname, tnc_port, agwlib_G_ask_port_information) != 0) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Could not attach to network TNC %s:%s.\n", tnc_hostname, tnc_port);
exit (EXIT_FAILURE);
}
/*
* Send command to ask what channels are available.
* The response will be handled by agw_cb_G_port_information.
*/
// FIXME: Need to do this again if we lose TNC and reattach to it.
/// should happen automatically now. agwlib_G_ask_port_information ();
while (1) {
SLEEP_SEC(1); // other places based on 1 second assumption.
poll_timing_test ();
}
} /* end main */
static void poll_timing_test (void)
{
int s;
for (s = 0; s < MAX_SESSIONS; s++) {
if (session[s].tt_count == 0) {
continue; // nothing to do
}
else if (session[s].tt_next <= session[s].tt_count) {
int rem = session[s].tt_count - session[s].tt_next + 1; // remaining to send.
agwlib_Y_outstanding_frames_for_station (session[s].channel, mycall, session[s].client_addr);
SLEEP_MS(10);
if (session[s].tx_queue_len > 128) continue; // enough queued up for now.
if (rem > 64) rem = 64; // add no more than 64 at a time.
int i;
for (i = 0; i < rem; i++) {
char c = 'a';
char stuff[AX25_MAX_INFO_LEN+2];
snprintf (stuff, sizeof(stuff), "%06d ", session[s].tt_next);
int k;
for (k = strlen(stuff); k < session[s].tt_length - 1; k++) {
stuff[k] = c;
c++;
if (c == 'z' + 1) c = 'A';
if (c == 'Z' + 1) c = '0';
if (c == '9' + 1) c = 'a';
}
stuff[k++] = '\r';
stuff[k++] = '\0';
agwlib_D_send_connected_data (session[s].channel, 0xF0, mycall, session[s].client_addr, strlen(stuff), stuff);
session[s].tt_next++;
}
}
else {
// All done queuing up the packets.
// Wait until they have all been sent and ack'ed by other end.
agwlib_Y_outstanding_frames_for_station (session[s].channel, mycall, session[s].client_addr);
SLEEP_MS(10);
if (session[s].tx_queue_len > 0) continue; // not done yet.
int elapsed = time(NULL) - session[s].tt_start_time;
if (elapsed <= 0) elapsed = 1; // avoid divide by 0
int byte_count = session[s].tt_count * session[s].tt_length;
char summary[100];
snprintf (summary, sizeof(summary), "%d bytes in %d seconds, %d bytes/sec, efficiency %d%% at 1200, %d%% at 9600.\r",
byte_count, elapsed, byte_count/elapsed,
byte_count * 8 * 100 / elapsed / 1200,
byte_count * 8 * 100 / elapsed / 9600);
agwlib_D_send_connected_data (session[s].channel, 0xF0, mycall, session[s].client_addr, strlen(summary), summary);
session[s].tt_count = 0; // all done.
}
}
} // end poll_timing_test
/*-------------------------------------------------------------------
*
* Name: agw_cb_C_connection_received
*
* Purpose: Callback for the "connection received" command from the TNC.
*
* Inputs: chan - Radio channel, first is 0.
*
* call_from - Address of other station.
*
* call_to - Callsign I responded to. (could be an alias.)
*
* data_len - Length of data field.
*
* data - Should look something like this for incoming:
* *** CONNECTED to Station xxx\r
*
* Description: Add to the sessions table.
*
*--------------------------------------------------------------------*/
/*-------------------------------------------------------------------
*
* Name: on_C_connection_received
*
* Purpose: Callback for the "connection received" command from the TNC.
*
* Inputs: chan - Radio channel, first is 0.
*
* call_from - Address of other station.
*
* call_to - My call.
* In the case of an incoming connect request (i.e. to
* a server) this is the callsign I responded to.
* It is possible to define additional aliases and respond
* to any one of them. It would be possible to have a server
* that responds to multiple names and behaves differently
* depending on the name.
*
* incoming - true(1) if other station made connect request.
* false(0) if I made request and other statio accepted.
*
* data - Should look something like this for incoming:
* *** CONNECTED to Station xxx\r
* and this for my request being accepted:
* *** CONNECTED With Station xxx\r
*
* session_id - Session id to be used in data transfer and
* other control functions related to this connection.
* Think of it like a file handle. Once it is open
* we usually don't care about the name anymore and
* and just refer to the handle. This is used to
* keep track of multiple connections at the same
* time. e.g. a server could be handling multiple
* clients at once on the same or different channels.
*
* Description: Add to the table of clients.
*
*--------------------------------------------------------------------*/
// old void agw_cb_C_connection_received (int chan, char *call_from, char *call_to, int data_len, char *data)
void on_C_connection_received (int chan, char *call_from, char *call_to, int incoming, char *data)
{
int s;
char *p;
char greeting[256];
for (p = data; *p != '\0'; p++) {
if (! isprint(*p)) *p = '\0'; // Remove any \r character at end.
}
s = find_session (chan, call_from, 1);
if (s >= 0) {
text_color_set(DW_COLOR_INFO);
dw_printf ("Begin session %d: %s\n", s, data);
// Send greeting.
snprintf (greeting, sizeof(greeting), "Welcome! Type ? for list of commands or HELP <command> for details.\r");
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
}
else {
text_color_set(DW_COLOR_INFO);
dw_printf ("Too many users already: %s\n", data);
// Sorry, too many users already.
snprintf (greeting, sizeof(greeting), "Sorry, maximum number of users has been exceeded. Try again later.\r");
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
// FIXME: Ideally we'd want to wait until nothing in the outgoing queue
// to that station so we know the rejection message was received.
SLEEP_SEC (10);
agwlib_d_disconnect (chan, mycall, call_from);
}
} /* end agw_cb_C_connection_received */
/*-------------------------------------------------------------------
*
* Name: agw_cb_d_disconnected
*
* Purpose: Process the "disconnected" command from the TNC.
*
* Inputs: chan - Radio channel.
*
* call_from - Address of other station.
*
* call_to - Callsign I responded to. (could be aliases.)
*
* data_len - Length of data field.
*
* data - Should look something like one of these:
* *** DISCONNECTED RETRYOUT With xxx\r
* *** DISCONNECTED From Station xxx\r
*
* Description: Remove from the sessions table.
*
*--------------------------------------------------------------------*/
void agw_cb_d_disconnected (int chan, char *call_from, char *call_to, int data_len, char *data)
{
int s;
char *p;
s = find_session (chan, call_from, 0);
for (p = data; *p != '\0'; p++) {
if (! isprint(*p)) *p = '\0'; // Remove any \r character at end.
}
text_color_set(DW_COLOR_INFO);
dw_printf ("End session %d: %s\n", s, data);
// Remove from session table.
if (s >= 0) {
memset (&(session[s]), 0, sizeof(struct session_s));
}
} /* end agw_cb_d_disconnected */
/*-------------------------------------------------------------------
*
* Name: agw_cb_D_connected_data
*
* Purpose: Process "connected ax.25 data" from the TNC.
*
* Inputs: chan - Radio channel.
*
* addr - Address of other station.
*
* msg - What the user sent us. Probably a command.
*
* Global In: tnc_sock - Socket for TNC.
*
* Description: Remove from the session table.
*
*--------------------------------------------------------------------*/
void agw_cb_D_connected_data (int chan, char *call_from, char *call_to, int data_len, char *data)
{
int s;
char *p;
char logit[AX25_MAX_INFO_LEN+100];
char *pcmd;
char *save;
s = find_session (chan, call_from, 0);
for (p = data; *p != '\0'; p++) {
if (! isprint(*p)) *p = '\0'; // Remove any \r character at end.
}
// TODO: Should timestamp to all output.
snprintf (logit, sizeof(logit), "%d,%d,%s: %s\n", s, chan, call_from, data);
text_color_set(DW_COLOR_INFO);
dw_printf ("%s", logit);
if (s < 0) {
// Uh oh. Data from some station when not connected.
text_color_set(DW_COLOR_ERROR);
dw_printf ("Internal error. Incoming data, no corresponding session.\n");
return;
}
// Process the command from user.
pcmd = strtok_r (data, " ", &save);
if (pcmd == NULL || strlen(pcmd) == 0) {
char greeting[80];
strlcpy (greeting, "Type ? for list of commands or HELP <command> for details.\r", sizeof(greeting));
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
return;
}
if (strcasecmp(pcmd, "who") == 0) {
// who - list people currently logged in.
int n;
char greeting[128];
snprintf (greeting, sizeof(greeting), "Session Channel User Since\r");
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
for (n = 0; n < MAX_SESSIONS; n++) {
if (session[n].client_addr[0]) {
// I think compiler is confused. It says up to 520 characters can be written.
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-truncation"
snprintf (greeting, sizeof(greeting), " %2d %d %-9s [time later]\r",
n, session[n].channel, session[n].client_addr);
#pragma GCC diagnostic pop
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
}
}
}
else if (strcasecmp(pcmd, "test") == 0) {
// test - timing test
// Send specified number of frames with optional length.
char *pcount = strtok_r (NULL, " ", &save);
char *plength = strtok_r (NULL, " ", &save);
session[s].tt_start_time = time(NULL);
session[s].tt_next = 1;
session[s].tt_length = 256;
session[s].tt_count = 1;
if (plength != NULL) {
session[s].tt_length = atoi(plength);
if (session[s].tt_length < 16) session[s].tt_length = 16;
if (session[s].tt_length > AX25_MAX_INFO_LEN) session[s].tt_length = AX25_MAX_INFO_LEN;
}
if (pcount != NULL) {
session[s].tt_count = atoi(pcount);
}
// The background polling will take it from here.
}
else if (strcasecmp(pcmd, "bye") == 0) {
// bye - disconnect.
char greeting[80];
strlcpy (greeting, "Thank you folks for kindly droppin' in. Y'all come on back now, ya hear?\r", sizeof(greeting));
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
// Ideally we'd want to wait until nothing in the outgoing queue
// to that station so we know the message was received.
SLEEP_SEC (10);
agwlib_d_disconnect (chan, mycall, call_from);
}
else if (strcasecmp(pcmd, "help") == 0 || strcasecmp(pcmd, "?") == 0) {
// help.
char greeting[80];
strlcpy (greeting, "Help not yet available.\r", sizeof(greeting));
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
}
else {
// command not recognized.
char greeting[80];
strlcpy (greeting, "Invalid command. Type ? for list of commands or HELP <command> for details.\r", sizeof(greeting));
agwlib_D_send_connected_data (chan, 0xF0, mycall, call_from, strlen(greeting), greeting);
}
} /* end agw_cb_D_connected_data */
/*-------------------------------------------------------------------
*
* Name: agw_cb_G_port_information
*
* Purpose: Process the port information "radio channels available" response from the TNC.
*
*
* Inputs: num_chan_avail - Number of radio channels available.
*
* chan_descriptions - Array of string pointers to form "Port99 description".
* Port1 is channel 0.
*
*--------------------------------------------------------------------*/
void agw_cb_G_port_information (int num_chan_avail, char *chan_descriptions[])
{
char *p;
int n;
text_color_set(DW_COLOR_INFO);
dw_printf("TNC has %d radio channel%s available:\n", num_chan_avail, (num_chan_avail != 1) ? "s" : "");
for (n = 0; n < num_chan_avail; n++) {
p = chan_descriptions[n];
// Expecting something like this: "Port1 first soundcard mono"
if (strncasecmp(p, "Port", 4) == 0 && isdigit(p[4])) {
int chan = atoi(p+4) - 1; // "Port1" is our channel 0.
if (chan >= 0 && chan < MAX_CHANS) {
char *desc = p + 4;
while (*desc != '\0' && (*desc == ' ' || isdigit(*desc))) {
desc++;
}
text_color_set(DW_COLOR_INFO);
dw_printf(" Channel %d: %s\n", chan, desc);
// Later? Use 'g' to get speed and maybe other properties?
// Though I'm not sure why we would care here.
/*
* Send command to register my callsign for incoming connect requests.
*/
agwlib_X_register_callsign (chan, mycall);
}
else {
text_color_set(DW_COLOR_ERROR);
dw_printf("Radio channel number is out of bounds: %s\n", p);
}
}
else {
text_color_set(DW_COLOR_ERROR);
dw_printf("Radio channel description not in expected format: %s\n", p);
}
}
} /* end agw_cb_G_port_information */
/*-------------------------------------------------------------------
*
* Name: agw_cb_Y_outstanding_frames_for_station
*
* Purpose: Process the "disconnected" command from the TNC.
*
* Inputs: chan - Radio channel.
*
* call_from - Should be my call.
*
* call_to - Callsign of other station.
*
* frame_count
*
* Description: Remove from the sessions table.
*
*--------------------------------------------------------------------*/
void agw_cb_Y_outstanding_frames_for_station (int chan, char *call_from, char *call_to, int frame_count)
{
int s;
s = find_session (chan, call_to, 0);
text_color_set(DW_COLOR_DEBUG); // FIXME temporary
dw_printf ("debug ----------------------> session %d, callback Y outstanding frame_count %d\n", s, frame_count);
// Update the transmit queue length
if (s >= 0) {
session[s].tx_queue_len = frame_count;
}
else {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Oops! Did not expect to be here.\n");
}
} /* end agw_cb_Y_outstanding_frames_for_station */
/*-------------------------------------------------------------------
*
* Name: find_session
*
* Purpose: Given a channel number and address (callsign), find existing
* table entry or create a new one.
*
* Inputs: chan - Radio channel number.
*
* addr - Address of station contacting us.
*
* create - If true, try create a new entry if not already there.
*
* Returns: "session id" which is an index into "session" array or -1 for failure.
*
*--------------------------------------------------------------------*/
static int find_session (int chan, char *addr, int create)
{
int i;
int s = -1;
// Is it there already?
//#if DEBUG
//
// text_color_set(DW_COLOR_DEBUG);
// dw_printf("find_session (%d, %s, %d)\n", chan, addr, create);
//#endif
for (i = 0; i < MAX_SESSIONS; i++) {
if (session[i].channel == chan && strcmp(session[i].client_addr, addr) == 0) {
s = i;
break;
}
}
if (s >= 0) return (s);
if (! create) return (-1);
// No, and there is a request to add a new entry.
// See if we have any available space.
s = -1;
for (i = 0; i < MAX_SESSIONS; i++) {
if (strlen(session[i].client_addr) == 0) {
s = i;
break;
}
}
if (s < 0) return (-1);
strlcpy (session[s].client_addr, addr, sizeof(session[s].client_addr));
session[s].channel = chan;
session[s].login_time = time(NULL);
return (s);
} /* end find_session */
/* end appserver.c */
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