New bus address scheme

1 files changed, 94 insertions, 8 deletions

diff --git a/comm/BusAccess.cc b/comm/BusAccess.cc
index 826146a..5383e91 100644
--- a/comm/BusAccess.cc
+++ b/comm/BusAccess.cc
@@ -24,8 +24,12 @@
 #include <ostream.h>
 #include <regex.h>
 #include <stdarg.h>
+#include <ctype.h>
 
 int UchBusAccess::Version = 3;
+const char* const UchBusAccess::DefaultBus = "127:2010";
+const sword UchBusAccess::DefaultBusPort = 2010;
+const char* const UchBusAccess::DefaultBusNet = "127";
 
 static int _BusDebug = 0;
 
@@ -407,19 +411,39 @@ UchBusAgent :: Emit (int id, const char* fmt, ...)
 	WriteString ("\n");
 }
 
-UchBusAccess :: UchBusAccess (const char* name, sword port)
+UchBusAccess :: UchBusAccess (const char* name, const char* bus)
 : UchDatagram (),
   UchBaseSignalHandler (*UchMpx, SigInt),
   Name (name),
   ListenPort (0),
-  BroadcastPort (port),
+  BroadcastPort (0),
   Server (0),
   Agents (),
   IdToSubscription (256),
   LocalSubscriptions ()
 {
-	/** set up datagram **/
-	UchInetAddress* a = new UchInetAddress (ANYADDR, port);
+
+
+	/** determine network list as well as broadcast port **/
+	/* (we accept addresses such as 123.231,123.123:2000 or 123.231 or :2000) */
+
+	/* first, let's find something to parse */
+	if (!bus || !*bus)
+		bus = getenv ("IVYBUS");
+	if (!bus || !*bus)
+		bus = DefaultBus;
+
+	/* then, let's get a port number. We'll parse network list later.*/
+	sword port;
+	char* q = strchr (bus, ':');
+	if (bus && (port = atoi (q+1)))
+		BroadcastPort = port;
+	else
+		BroadcastPort = DefaultBusPort;
+
+
+	/** set up UDP broadcast socket **/
+	UchInetAddress* a = new UchInetAddress (ANYADDR, BroadcastPort);
 	BindTo (a);
 	if (!Open ()) {
 		perror ("Cannot open socket: ");
@@ -435,7 +459,7 @@ UchBusAccess :: UchBusAccess (const char* name, sword port)
 	}
 
 	if (Bind () < 0) {
-		cerr << "cannot bind socket to port " << port << "\n";
+		cerr << "cannot bind socket to port " << BroadcastPort << "\n";
 		return;
 	}
 //	SetMode (IOReadWrite);
@@ -450,11 +474,73 @@ UchBusAccess :: UchBusAccess (const char* name, sword port)
 	}
 	ListenPort = a->Port ();
 	
-	/** emit handshake on datagram **/
+	/** broadcast handshakes on every network **/
 	char handshake[32];
 	sprintf (handshake, "%d %hu\n", Version, ListenPort);
-	UchInetAddress ba (BROADCAST, BroadcastPort);
-	Send ((byte*)handshake, strlen (handshake), ba);
+
+	/* if we only have a port number, resort to default value for network */
+	if (bus == q)
+		bus = DefaultBusNet;
+
+	/* parse network list and send broadcast handshakes.
+	   This is long and painful but inet_aton is sloppy.
+	   If someone knows other builtin routines that do that... */
+	unsigned long mask = 0xffffffff; 
+	unsigned char elem = 0;
+	int numdigit = 0;
+	int numelem = 0;
+	int error = 0;
+
+	for (;;) {
+		/* address elements are up to 3 digits... */
+		if (!error && isdigit (*bus)) {
+			if (numdigit < 3 && numelem < 4) {
+				elem = 10 * elem +  *bus -'0';
+			} else {
+				error = 1;
+			}
+
+		/* ... terminated by a point, a comma or a colon, or the end of string */
+		} else if (!error && (*bus == '.' || *bus == ',' || *bus == ':' || *bus == '\0')) {
+			mask = (mask ^ (0xff << (8*(3-numelem)))) | (elem << (8*(3-numelem)));
+
+			/* after a point, expect next address element */
+			if (*bus == '.') {
+				numelem++;
+
+			/* addresses are terminated by a comma or end of string */
+			} else {
+				printf ("Broadcasting on network %lx, port %d\n", mask, BroadcastPort);
+				UchInetAddress ba (mask, BroadcastPort);
+				Send ((byte*)handshake, strlen (handshake), ba);
+				numelem = 0;
+				mask = 0xffffffff;
+			}
+			numdigit = 0;
+			elem = 0;
+
+		/* recover from bad addresses at next comma or colon or at end of string */
+		} else if (*bus == ',' || *bus == ':' || *bus == '\0') {
+			fprintf (stderr, "bad broadcast address\n");
+			elem = 0;
+			numelem = 0;
+			numdigit = 0;
+			mask = 0xffffffff;
+			error = 0;
+
+		/* ignore spaces */
+		} else if (*bus == ' ') {
+
+		  /* everything else is illegal */
+		} else {
+			error = 1;
+		}
+
+		/* end of string or colon */
+		if (*bus == '\0' || *bus == ':')
+			break;
+		++bus;
+	}
 
 	/* add to main loop */
 	Add (UchMpx);