Issue 186 - Copy KISS frames between TCP KISS clients.

Author: wb2osz

config.c

@@ -854,6 +854,7 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	p_misc_config->agwpe_port = DEFAULT_AGWPE_PORT;
 	p_misc_config->kiss_port = DEFAULT_KISS_PORT;
 	p_misc_config->enable_kiss_pt = 0;				/* -p option */
+	p_misc_config->kiss_copy = 0;
 
 	/* Defaults from http://info.aprs.net/index.php?title=SmartBeaconing */
 
@@ -4332,6 +4333,16 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	    }
 	  }
 
+
+/*
+ * KISSCOPY 		- Data from network KISS client is copied to all others.
+ */
+
+	  else if (strcasecmp(t, "KISSCOPY") == 0) {
+	    p_misc_config->kiss_copy = 1;
+	  }
+
+
 /*
  * GPSNMEA		- Device name for reading from GPS receiver.
  */
@@ -4712,6 +4723,7 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	      p_misc_config->maxframe_basic = n;
 	    }
 	    else {
+	      p_misc_config->maxframe_basic = AX25_K_MAXFRAME_BASIC_DEFAULT;
 	      text_color_set(DW_COLOR_ERROR);
               dw_printf ("Line %d: Invalid MAXFRAME value outside range of %d to %d. Using default %d.\n",
 			line, AX25_K_MAXFRAME_BASIC_MIN, AX25_K_MAXFRAME_BASIC_MAX, p_misc_config->maxframe_basic);
@@ -4737,6 +4749,7 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	      p_misc_config->maxframe_extended = n;
 	    }
 	    else {
+	      p_misc_config->maxframe_extended = AX25_K_MAXFRAME_EXTENDED_DEFAULT;
 	      text_color_set(DW_COLOR_ERROR);
               dw_printf ("Line %d: Invalid EMAXFRAME value outside of range %d to %d. Using default %d.\n",
 			line, AX25_K_MAXFRAME_EXTENDED_MIN, AX25_K_MAXFRAME_EXTENDED_MAX, p_misc_config->maxframe_extended);

config.h

@@ -35,6 +35,7 @@ struct misc_config_s {
 
 	int agwpe_port;		/* Port number for the "AGW TCPIP Socket Interface" */
 	int kiss_port;		/* Port number for the "TCP KISS" protocol. */
+	int kiss_copy;		/* Data from network KISS client is copied to all others. */
 	int enable_kiss_pt;	/* Enable pseudo terminal for KISS. */
 				/* Want this to be off by default because it hangs */
 				/* after a while if nothing is reading from other end. */

kiss_frame.c

@@ -93,6 +93,7 @@
 #include "tq.h"
 #include "xmit.h"
 #include "version.h"
+#include "kissnet.h"
 
 
 /* In server.c.  Should probably move to some misc. function file. */
@@ -506,7 +507,7 @@ void kiss_rec_byte (kiss_frame_t *kf, unsigned char ch, int debug, int client, v
  *		debug		- Debug option is selected.
  *
  *		client		- Client app number for TCP KISS.
- *				  Ignored for pseudo termal and serial port.
+ *				  Should be -1 for pseudo termal and serial port.
  *
  *		sendfun		- Function to send something to the client application.
  *				  "Set Hardware" can send a response.
@@ -522,7 +523,7 @@ void kiss_rec_byte (kiss_frame_t *kf, unsigned char ch, int debug, int client, v
 
 void kiss_process_msg (unsigned char *kiss_msg, int kiss_len, int debug, int client, void (*sendfun)(int,int,unsigned char*,int,int))
 {
-	int port;
+	int port;		// Should rename to chan because that's what we use everywhere else.
 	int cmd;
 	packet_t pp;
 	alevel_t alevel;
@@ -534,6 +535,10 @@ void kiss_process_msg (unsigned char *kiss_msg, int kiss_len, int debug, int cli
 	{
 	  case KISS_CMD_DATA_FRAME:				/* 0 = Data Frame */
 
+	    if (client >= 0) {
+	      kissnet_copy (kiss_msg, kiss_len, port, cmd, client);
+	    }
+
 	    /* Special hack - Discard apparently bad data from Linux AX25. */
 
 	    /* Note July 2017: There is a variant of of KISS, called SMACK, that assumes */
@@ -545,6 +550,36 @@ void kiss_process_msg (unsigned char *kiss_msg, int kiss_len, int debug, int cli
 	    /* Our current default is a maximum of 6 channels but it is easily */
 	    /* increased by changing one number and recompiling. */
 
+// Additional information, from Mike Playle, December 2018, for Issue #42
+//
+//	I came across this the other day with Xastir, and took a quick look.
+//	The problem is fixable without the kiss_frame.c hack, which doesn't help with Xastir anyway.
+//
+//	Workaround
+//
+//	After the kissattach command, put the interface into CRC mode "none" with a command like this:
+//
+//	# kissparms -c 1 -p radio
+//
+//	Analysis
+//
+//	The source of this behaviour is the kernel's KISS implementation:
+//
+//	https://elixir.bootlin.com/linux/v4.9/source/drivers/net/hamradio/mkiss.c#L489
+//
+//	It defaults to starting in state CRC_MODE_SMACK_TEST and ending up in mode CRC_NONE
+//	after the first two packets, which have their framing byte modified by this code in the process.
+//	It looks to me like deliberate behaviour on the kernel's part.
+//
+//	Setting the CRC mode explicitly before sending any packets stops this state machine from running.
+//
+//	Is this a bug? I don't know - that's up to you! Maybe it would make sense for Direwolf to set
+//	the CRC mode itself, or to expect this behaviour and ignore these flags on the first packets
+//	received from the Linux pty.
+//
+//	This workaround seems sound to me, though, so perhaps this is just a documentation issue.
+
+
 	    if (kiss_len > 16 &&
 	        (port == 2 || port == 8) &&
 		 kiss_msg[1] == 'Q' << 1 &&

kissnet.c

@@ -159,6 +159,7 @@ static THREAD_F connect_listen_thread (void *arg);
 static THREAD_F kissnet_listen_thread (void *arg);
 
 
+static struct misc_config_s *s_misc_config_p;
 
 static int kiss_debug = 0;		/* Print information flowing from and to client. */
 
@@ -204,6 +205,8 @@ void kissnet_init (struct misc_config_s *mc)
 	pthread_t cmd_listen_tid[MAX_NET_CLIENTS];
 	int e;
 #endif
+	s_misc_config_p = mc;
+
 	int kiss_port = mc->kiss_port;		/* default 8001 but easily changed. */
 
 
@@ -650,6 +653,90 @@ void kissnet_send_rec_packet (int chan, int kiss_cmd, unsigned char *fbuf, int f
 } /* end kissnet_send_rec_packet */
 
 
+/*-------------------------------------------------------------------
+ *
+ * Name:        kissnet_copy
+ *
+ * Purpose:     Send data from one network KISS client to all others.
+ *
+ * Inputs:	in_msg		- KISS frame data without the framing or escapes.
+ *				  The first byte is channel (port) and command (should be data).
+ *
+ *		in_len 		- Number of bytes in above.
+ *
+ *		chan		- Channel.  Redundant because it is also in first byte of kiss_msg.
+ *				  Not currently used.
+ *
+ *		cmd		- KISS command nybble.  Redundant because it is in first byte.
+ *				  Should be 0 because I'm expecting this only for data.
+ *
+ *		from_client	- Number of network (TCP) client instance.
+ *				  Should be 0, 1, 2, ...
+ *
+ *
+ * Global In:	kiss_copy	- From misc. configuration.
+ *				  This enables the feature.
+ *
+ *
+ * Description:	Send message to any attached network KISS clients, other than the one where it came from.
+ *		Enable this by putting KISSCOPY in the configuration file.
+ *		Note that this applies only to network (TCP) KISS clients, not serial port, or pseudo terminal.
+ *
+ *
+ *--------------------------------------------------------------------*/
+
+
+void kissnet_copy (unsigned char *in_msg, int in_len, int chan, int cmd, int from_client)
+{
+	unsigned char kiss_buff[2 * AX25_MAX_PACKET_LEN];
+	int kiss_len;
+	int err;
+	int send_to;
+
+	(void) chan;
+	(void) cmd;
+
+	if (s_misc_config_p->kiss_copy) {
+
+	  for (send_to = 0; send_to < MAX_NET_CLIENTS;  send_to++) {
+
+	    if (send_to != from_client && client_sock[send_to] != -1) {
+
+	      kiss_len = kiss_encapsulate (in_msg, in_len, 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 = SOCK_SEND(client_sock[send_to], (char*)kiss_buff, kiss_len);
+	      if (err == SOCKET_ERROR)
+	      {
+	        text_color_set(DW_COLOR_ERROR);
+	        dw_printf ("\nError %d copying message to KISS client %d application.  Closing connection.\n\n", WSAGetLastError(), send_to);
+	        closesocket (client_sock[send_to]);
+	        client_sock[send_to] = -1;
+	        WSACleanup();
+	      }
+#else
+              err = SOCK_SEND (client_sock[send_to], kiss_buff, kiss_len);
+	      if (err <= 0)
+	      {
+	        text_color_set(DW_COLOR_ERROR);
+	        dw_printf ("\nError copying message to KISS client %d application.  Closing connection.\n\n", send_to);
+	        close (client_sock[send_to]);
+	        client_sock[send_to] = -1;
+	      }
+#endif
+	    } // if origin and destination different.
+	  } // loop over all KISS network clients.
+	} // Feature enabled.
+
+} /* end kissnet_copy */
+
+
 
 /*-------------------------------------------------------------------
  *

kissnet.h

@@ -17,5 +17,7 @@ void kissnet_send_rec_packet (int chan, int kiss_cmd, unsigned char *fbuf,  int
 
 void kiss_net_set_debug (int n);
 
+void kissnet_copy (unsigned char *kiss_msg, int kiss_len, int chan, int cmd, int from_client);
+
 
 /* end kissnet.h */