More completely decode the frame control field of an FDDI frame.

In the summary display for FDDI frames, make the protocol FDDI and the
info field the description of the frame control field (which will be
overridden by other protocols, if the frame is an async LLC frame).

svn path=/trunk/; revision=558

1 files changed, 93 insertions, 6 deletions

diff --git a/packet-fddi.c b/packet-fddi.c
index 73ab41344d..81847521b4 100644
--- a/packet-fddi.c
+++ b/packet-fddi.c
@@ -3,7 +3,7 @@
  *
  * Laurent Deniel <deniel@worldnet.fr>
  *
- * $Id: packet-fddi.c,v 1.18 1999/08/24 03:19:22 guy Exp $
+ * $Id: packet-fddi.c,v 1.19 1999/08/24 06:01:45 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -33,6 +33,7 @@
 # include <sys/types.h>
 #endif
 
+#include <stdio.h>
 #include <glib.h>
 #include "packet.h"
 #include "resolv.h"
@@ -69,6 +70,15 @@ static int hf_fddi_src = -1;
 #define FDDI_FC_IMP_ASYNC_MAX	0x6f
 #define FDDI_FC_IMP_SYNC	0xe0		/* Implementor Synch. */
 
+#define FDDI_FC_CLFF		0xF0		/* Class/Length/Format bits */
+#define FDDI_FC_ZZZZ		0x0F		/* Control bits */
+
+/*
+ * Async frame ZZZZ bits:
+ */
+#define FDDI_FC_ASYNC_R		0x08		/* Reserved */
+#define FDDI_FC_ASYNC_PRI	0x07		/* Priority */
+
 #define FDDI_HEADER_SIZE	13
 
 /* field positions */
@@ -166,12 +176,84 @@ capture_fddi(const u_char *pd, guint32 cap_len, packet_counts *ld) {
 
 } /* capture_fddi */
 
+static gchar *
+fddifc_to_str(int fc)
+{
+  static gchar strbuf[128+1];
+
+  switch (fc) {
+
+  case FDDI_FC_VOID:			/* Void frame */
+    return "Void frame";
+
+  case FDDI_FC_NRT:			/* Nonrestricted token */
+    return "Nonrestricted token";
+
+  case FDDI_FC_RT:			/* Restricted token */
+    return "Restricted token";
+
+  case FDDI_FC_SMT_INFO:		/* SMT Info */
+    return "SMT info";
+
+  case FDDI_FC_SMT_NSA:			/* SMT Next station adrs */
+    return "SMT Next station address";
+
+  case FDDI_FC_MAC_BEACON:		/* MAC Beacon frame */
+    return "MAC beacon";
+
+  case FDDI_FC_MAC_CLAIM:		/* MAC Claim frame */
+    return "MAC claim token";
+
+  default:
+    switch (fc & FDDI_FC_CLFF) {
+
+    case FDDI_FC_MAC:
+      sprintf(strbuf, "MAC frame, control %x", fc & FDDI_FC_ZZZZ);
+      return strbuf;
+
+    case FDDI_FC_SMT:
+      sprintf(strbuf, "SMT frame, control %x", fc & FDDI_FC_ZZZZ);
+      return strbuf;
+
+    case FDDI_FC_LLC_ASYNC:
+      if (fc & FDDI_FC_ASYNC_R)
+        sprintf(strbuf, "Async LLC frame, control %x", fc & FDDI_FC_ZZZZ);
+      else
+        sprintf(strbuf, "Async LLC frame, priority %d",
+			fc & FDDI_FC_ASYNC_PRI);
+      return strbuf;
+
+    case FDDI_FC_LLC_SYNC:
+      if (fc & FDDI_FC_ZZZZ) {
+        sprintf(strbuf, "Sync LLC frame, control %x", fc & FDDI_FC_ZZZZ);
+        return strbuf;
+      } else
+        return "Sync LLC frame";
+
+    case FDDI_FC_IMP_ASYNC:
+      sprintf(strbuf, "Implementor async frame, control %x",
+			fc & FDDI_FC_ZZZZ);
+      return strbuf;
+
+    case FDDI_FC_IMP_SYNC:
+      sprintf(strbuf, "Implementor sync frame, control %x",
+			fc & FDDI_FC_ZZZZ);
+      return strbuf;
+      break;
+
+    default:
+      return NULL;
+    }
+  }
+}
+
 void dissect_fddi(const u_char *pd, frame_data *fd, proto_tree *tree,
 		gboolean bitswapped)
 {
   int        offset = 0, fc;
   proto_tree *fh_tree;
   proto_item *ti;
+  gchar      *fc_str;
   u_char     src[6], dst[6];
   u_char     src_swapped[6], dst_swapped[6];
 
@@ -191,6 +273,7 @@ void dissect_fddi(const u_char *pd, frame_data *fd, proto_tree *tree,
   }
 
   fc = (int) pd[FDDI_P_FC];
+  fc_str = fddifc_to_str(fc);
 
   if (check_col(fd, COL_RES_DL_SRC))
     col_add_str(fd, COL_RES_DL_SRC, get_ether_name(src));
@@ -201,17 +284,16 @@ void dissect_fddi(const u_char *pd, frame_data *fd, proto_tree *tree,
   if (check_col(fd, COL_UNRES_DL_DST))
     col_add_str(fd, COL_UNRES_DL_DST, ether_to_str(dst));
   if (check_col(fd, COL_PROTOCOL))
-    col_add_str(fd, COL_PROTOCOL, "N/A");
+    col_add_str(fd, COL_PROTOCOL, "FDDI");
   if (check_col(fd, COL_INFO))
-    col_add_str(fd, COL_INFO, "FDDI");
+    col_add_str(fd, COL_INFO, fc_str);
 
   offset = FDDI_HEADER_SIZE;
 
   if (tree) {
 	ti = proto_tree_add_item_format(tree, proto_fddi, 0, offset, NULL,
 		"Fiber Distributed Data Interface, %s",
-		(fc >= FDDI_FC_LLC_ASYNC_MIN && fc <= FDDI_FC_LLC_ASYNC_MAX) ?
-			  "Async LLC" : "unsupported FC");
+		(fc_str == NULL) ? "Unknown frame type" : fc_str);
 
       swap_mac_addr(dst_swapped, (u_char*)&pd[FDDI_P_DHOST]);
       swap_mac_addr(src_swapped, (u_char*)&pd[FDDI_P_SHOST]);
@@ -225,7 +307,7 @@ void dissect_fddi(const u_char *pd, frame_data *fd, proto_tree *tree,
       proto_tree_add_item_hidden(fh_tree, hf_fddi_dst, FDDI_P_DHOST, 6, dst_swapped);
       proto_tree_add_item_hidden(fh_tree, hf_fddi_dst, FDDI_P_SHOST, 6, src_swapped);
 
-    }
+  }
   switch (fc) {
 
     /* From now, only 802.2 SNAP (Async. LCC frame) is supported */
@@ -261,6 +343,11 @@ proto_register_fddi(void)
 {
 	static hf_register_info hf[] = {
 
+		/*
+		 * XXX - we want this guy to have his own private formatting
+		 * routine, using "fc_to_str()"; if "fc_to_str()" returns
+		 * NULL, just show the hex value, else show the string.
+		 */
 		{ &hf_fddi_fc,
 		{ "Frame Control",	"fddi.fc", FT_UINT8, NULL }},