Have "get_xdlc_control()" and "dissect_xdlc_control()" just return a

Boolean indicating whether the frame has any payload to dissect or not.

svn path=/trunk/; revision=556

3 files changed, 59 insertions, 59 deletions

diff --git a/packet-llc.c b/packet-llc.c
index 819cd1b65a..76aeb58af8 100644
--- a/packet-llc.c
+++ b/packet-llc.c
@@ -2,7 +2,7 @@
  * Routines for IEEE 802.2 LLC layer
  * Gilbert Ramirez <gramirez@tivoli.com>
  *
- * $Id: packet-llc.c,v 1.20 1999/08/23 22:47:13 guy Exp $
+ * $Id: packet-llc.c,v 1.21 1999/08/23 23:24:35 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@unicom.net>
@@ -163,7 +163,7 @@ void
 capture_llc(const u_char *pd, int offset, guint32 cap_len, packet_counts *ld) {
 
 	int		is_snap;
-	int		control;
+	int		has_payload;
 	guint16		etype;
 	capture_func_t	*capture;
 
@@ -184,13 +184,12 @@ capture_llc(const u_char *pd, int offset, guint32 cap_len, packet_counts *ld) {
 	 * extended operation, so we don't need to determine whether
 	 * it's basic or extended operation; is that the case?
 	 */
-	control = get_xdlc_control(pd, offset+2, pd[offset+1] & 0x01, TRUE);
+	has_payload = get_xdlc_control(pd, offset+2, pd[offset+1] & 0x01, TRUE);
 
 	if (is_snap) {
-		if (control == XDLC_I || control == (XDLC_U|XDLC_UI)) {
+		if (has_payload) {
 			/*
-			 * Unnumbered Information - analyze it based on
-			 * the Ethernet packet type.
+			 * This frame has a payload to be analyzed.
 			 */
 			etype  = (pd[offset+6] << 8) | pd[offset+7];
 			offset += 8;
@@ -198,10 +197,9 @@ capture_llc(const u_char *pd, int offset, guint32 cap_len, packet_counts *ld) {
 		}
 	}		
 	else {
-		if (control == XDLC_I || control == (XDLC_U|XDLC_UI)) {
+		if (has_payload) {
 			/*
-			 * Unnumbered Information - analyze it based on
-			 * the DSAP.
+			 * This frame has a payload to be analyzed.
 			 */
 			capture = sap_capture_func(pd[offset]);
 
@@ -224,7 +222,7 @@ dissect_llc(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
 	proto_tree	*llc_tree = NULL;
 	proto_item	*ti;
 	int		is_snap;
-	int		control;
+	int		has_payload;
 	guint16		etype;
 	dissect_func_t	*dissect;
 
@@ -257,8 +255,8 @@ dissect_llc(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
 	 * extended operation, so we don't need to determine whether
 	 * it's basic or extended operation; is that the case?
 	 */
-	control = dissect_xdlc_control(pd, offset+2, fd, llc_tree, hf_llc_ctrl,
-	    pd[offset+1] & 0x01, TRUE);
+	has_payload = dissect_xdlc_control(pd, offset+2, fd, llc_tree,
+				hf_llc_ctrl, pd[offset+1] & 0x01, TRUE);
 
 	/*
 	 * XXX - do we want to append the SAP information to the stuff
@@ -273,10 +271,9 @@ dissect_llc(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
 			proto_tree_add_item(llc_tree, hf_llc_oui, offset+3, 3,
 				pd[offset+3] << 16 | pd[offset+4] << 8 | pd[offset+5]);
 		}
-		if (control == (XDLC_U|XDLC_UI)) {
+		if (has_payload) {
 			/*
-			 * Unnumbered Information - dissect it based on
-			 * the Ethernet packet type.
+			 * This frame has a payload to be analyzed.
 			 */
 			etype = pntohs(&pd[offset+6]);
 			offset += 8;
@@ -291,10 +288,9 @@ dissect_llc(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
 				val_to_str(pd[offset], sap_vals, "%02x"));
 		}
 
-		if (control == (XDLC_U|XDLC_UI)) {
+		if (has_payload) {
 			/*
-			 * Unnumbered Information - dissect it based on
-			 * the DSAP.
+			 * This frame has a payload to be analyzed.
 			 */
 			dissect = sap_dissect_func(pd[offset]);
 
diff --git a/xdlc.c b/xdlc.c
index 896b52ab33..02a4e60a2d 100644
--- a/xdlc.c
+++ b/xdlc.c
@@ -2,7 +2,7 @@
  * Routines for use by various SDLC-derived protocols, such as HDLC
  * and its derivatives LAPB, IEEE 802.2 LLC, etc..
  *
- * $Id: xdlc.c,v 1.4 1999/08/23 22:47:13 guy Exp $
+ * $Id: xdlc.c,v 1.5 1999/08/23 23:24:36 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@unicom.net>
@@ -66,6 +66,31 @@
 #define XDLC_REJ		0x08	/* Reject */
 #define XDLC_SREJ		0x0C	/* Selective reject */
 
+/*
+ * U-format modifiers.
+ */
+#define XDLC_U_MODIFIER_MASK	0xEC
+#define XDLC_UI		0x00	/* Unnumbered Information */
+#define XDLC_UP		0x20	/* Unnumbered Poll */
+#define XDLC_DISC	0x40	/* Disconnect (command) */
+#define XDLC_RD		0x40	/* Request Disconnect (response) */
+#define XDLC_UA		0x60	/* Unnumbered Acknowledge */
+#define XDLC_SNRM	0x80	/* Set Normal Response Mode */
+#define XDLC_TEST	0xC0	/* Test */
+#define XDLC_SIM	0x04	/* Set Initialization Mode (command) */
+#define XDLC_RIM	0x04	/* Request Initialization Mode (response) */
+#define XDLC_FRMR	0x84	/* Frame reject */
+#define XDLC_CFGR	0xC4	/* Configure */
+#define XDLC_SARM	0x0C	/* Set Asynchronous Response Mode (command) */
+#define XDLC_DM		0x0C	/* Disconnected mode (response) */
+#define XDLC_SABM	0x2C	/* Set Asynchronous Balanced Mode */
+#define XDLC_SARME	0x4C	/* Set Asynchronous Response Mode Extended */
+#define XDLC_SABME	0x6C	/* Set Asynchronous Balanced Mode Extended */
+#define XDLC_RESET	0x8C	/* Reset */
+#define XDLC_XID	0xAC	/* Exchange identification */
+#define XDLC_SNRME	0xCC	/* Set Normal Response Mode Extended */
+#define XDLC_BCN	0xEC	/* Beacon */
+
 static const value_string stype_vals[] = {
     { XDLC_RR,   "Receiver ready" },
     { XDLC_RNR,  "Receiver not ready" },
@@ -167,9 +192,9 @@ get_xdlc_control(const u_char *pd, int offset, int is_response, int is_extended)
 
     case XDLC_S:
         /*
-	 * Supervisory frame.
+	 * Supervisory frame - no higher-layer payload.
 	 */
-	return XDLC_S;
+	return FALSE;
 
     case XDLC_U:
 	/*
@@ -185,17 +210,15 @@ get_xdlc_control(const u_char *pd, int offset, int is_response, int is_extended)
 	control = pd[offset];
 
 	/*
-	 * Return the modifier as well as the XDLC_U bits, so that
-	 * our caller knows whether the packet is UI or something
-	 * else.
+	 * This frame has payload only if it's a UI frame.
 	 */
-	return control & (XDLC_U_MODIFIER_MASK|0x03);
+	return (control & XDLC_U_MODIFIER_MASK) == XDLC_UI;
 
     default:
 	/*
-	 * Information frame.
+	 * Information frame - has higher-layer payload.
 	 */
-	return XDLC_I;
+	return TRUE;
     }
 }
 
@@ -297,7 +320,11 @@ dissect_xdlc_control(const u_char *pd, int offset, frame_data *fd,
 			"Supervisory frame", NULL));
 	    }
 	}
-	return XDLC_S;
+
+	/*
+	 * Supervisory frames have no higher-layer payload to be analyzed.
+	 */
+	return FALSE;
 
     case XDLC_U:
 	/*
@@ -349,11 +376,9 @@ dissect_xdlc_control(const u_char *pd, int offset, frame_data *fd,
 	}
 
 	/*
-	 * Return the modifier as well as the XDLC_U bits, so that
-	 * our caller knows whether the packet is UI or something
-	 * else.
+	 * This frame has payload only if it's a UI frame.
 	 */
-	return control & (XDLC_U_MODIFIER_MASK|0x03);
+	return (control & XDLC_U_MODIFIER_MASK) == XDLC_UI;
 
     default:
 	/*
@@ -415,6 +440,10 @@ dissect_xdlc_control(const u_char *pd, int offset, frame_data *fd,
 			NULL, "Information frame"));
 	    }
 	}
-	return XDLC_I;
+
+	/*
+	 * Information frames have higher-layer payload to be analyzed.
+	 */
+	return TRUE;
     }
 }
diff --git a/xdlc.h b/xdlc.h
index 3f2bc0e8bf..69fb908c34 100644
--- a/xdlc.h
+++ b/xdlc.h
@@ -2,7 +2,7 @@
  * Define *DLC frame types, and routine to dissect the control field of
  * a *DLC frame.
  *
- * $Id: xdlc.h,v 1.2 1999/08/23 22:47:13 guy Exp $
+ * $Id: xdlc.h,v 1.3 1999/08/23 23:24:36 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@unicom.net>
@@ -32,31 +32,6 @@
 #define XDLC_S		0x01	/* Supervisory frames */
 #define XDLC_U		0x03	/* Unnumbered frames */
 
-/*
- * U-format modifiers.
- */
-#define XDLC_U_MODIFIER_MASK	0xEC
-#define XDLC_UI		0x00	/* Unnumbered Information */
-#define XDLC_UP		0x20	/* Unnumbered Poll */
-#define XDLC_DISC	0x40	/* Disconnect (command) */
-#define XDLC_RD		0x40	/* Request Disconnect (response) */
-#define XDLC_UA		0x60	/* Unnumbered Acknowledge */
-#define XDLC_SNRM	0x80	/* Set Normal Response Mode */
-#define XDLC_TEST	0xC0	/* Test */
-#define XDLC_SIM	0x04	/* Set Initialization Mode (command) */
-#define XDLC_RIM	0x04	/* Request Initialization Mode (response) */
-#define XDLC_FRMR	0x84	/* Frame reject */
-#define XDLC_CFGR	0xC4	/* Configure */
-#define XDLC_SARM	0x0C	/* Set Asynchronous Response Mode (command) */
-#define XDLC_DM		0x0C	/* Disconnected mode (response) */
-#define XDLC_SABM	0x2C	/* Set Asynchronous Balanced Mode */
-#define XDLC_SARME	0x4C	/* Set Asynchronous Response Mode Extended */
-#define XDLC_SABME	0x6C	/* Set Asynchronous Balanced Mode Extended */
-#define XDLC_RESET	0x8C	/* Reset */
-#define XDLC_XID	0xAC	/* Exchange identification */
-#define XDLC_SNRME	0xCC	/* Set Normal Response Mode Extended */
-#define XDLC_BCN	0xEC	/* Beacon */
-
 int get_xdlc_control(const u_char *pd, int offset, int is_response,
   int extended);