Pull a lot of common code for handling 802.3 frames (i.e., frames with a

length field rather than an Ethernet type field) into a
"dissect_802_3()" routine.

In that routine, catch exceptions thrown by the IPX or LLC dissector or
dissectors under them, so that the trailer information is added to the
tree even if an exception is thrown (similar to what "ethertype()"
does).

svn path=/trunk/; revision=3002

1 files changed, 7 insertions, 62 deletions

diff --git a/packet-vlan.c b/packet-vlan.c
index cf072f79e0..d0430b0a20 100644
--- a/packet-vlan.c
+++ b/packet-vlan.c
@@ -1,7 +1,7 @@
 /* packet-vlan.c
  * Routines for VLAN 802.1Q ethernet header disassembly
  *
- * $Id: packet-vlan.c,v 1.32 2001/02/05 02:47:31 guy Exp $
+ * $Id: packet-vlan.c,v 1.33 2001/02/08 07:08:05 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -37,6 +37,7 @@
 
 #include <glib.h>
 #include "packet.h"
+#include "packet-ieee8023.h"
 #include "packet-ipx.h"
 #include "packet-llc.h"
 #include "etypes.h"
@@ -51,9 +52,6 @@ static int hf_vlan_trailer = -1;
 
 static gint ett_vlan = -1;
 
-static dissector_handle_t ipx_handle;
-static dissector_handle_t llc_handle;
-
 void
 capture_vlan(const u_char *pd, int offset, packet_counts *ld ) {
   guint16 encap_proto;
@@ -79,8 +77,6 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
   proto_tree *ti;
   guint16 tci,encap_proto;
   volatile gboolean is_802_2;
-  tvbuff_t *volatile next_tvb;
-  tvbuff_t *volatile trailer_tvb;
   proto_tree *volatile vlan_tree;
 
   if (check_col(pinfo->fd, COL_PROTOCOL))
@@ -106,37 +102,8 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     proto_tree_add_uint(vlan_tree, hf_vlan_id, tvb, 0, 2, tci);
   }
 
-  encap_proto = tvb_get_ntohs( tvb, 2 );
-  if ( encap_proto <= IEEE_802_3_MAX_LEN) {
-    /* Give the next dissector only 'encap_proto' number of bytes */
-    proto_tree_add_uint(vlan_tree, hf_vlan_len, tvb, 2, 2, encap_proto);
-    TRY {
-       next_tvb = tvb_new_subset(tvb, 4, encap_proto, encap_proto);
-       trailer_tvb = tvb_new_subset(tvb, 4 + encap_proto, -1, -1);
-    }
-    CATCH2(BoundsError, ReportedBoundsError) {
-      /* Either:
-
-           the packet doesn't have "encap_proto" bytes worth of
-           captured data left in it - or it may not even have
-           "encap_proto" bytes worth of data in it, period -
-           so the "tvb_new_subset()" creating "next_tvb"
-           threw an exception
-
-         or
-
-           the packet has exactly "encap_proto" bytes worth of
-           captured data left in it, so the "tvb_new_subset()"
-           creating "trailer_tvb" threw an exception.
-
-         In either case, this means that all the data in the frame
-         is within the length value, so we give all the data to the
-         next protocol and have no trailer. */
-      next_tvb = tvb_new_subset(tvb, 4, -1, encap_proto);
-      trailer_tvb = NULL;
-    }
-    ENDTRY;
-
+  encap_proto = tvb_get_ntohs(tvb, 2);
+  if (encap_proto <= IEEE_802_3_MAX_LEN) {
     /* Is there an 802.2 layer? I can tell by looking at the first 2
        bytes after the VLAN header. If they are 0xffff, then what
        follows the VLAN header is an IPX payload, meaning no 802.2.
@@ -146,7 +113,7 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
        802.2 layer inside the VLAN layer */
     is_802_2 = TRUE;
     TRY {
-	    if (tvb_get_ntohs(next_tvb, 2) == 0xffff) {
+	    if (tvb_get_ntohs(tvb, 4) == 0xffff) {
 	      is_802_2 = FALSE;
 	    }
     }
@@ -155,25 +122,9 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 
     }
     ENDTRY;
-    if (is_802_2 ) {
-      /* 802.2 LLC */
-      call_dissector(llc_handle, next_tvb, pinfo, tree);
-    } else {
-      call_dissector(ipx_handle, next_tvb, pinfo, tree);
-    }
 
-    /* If there's some bytes left over, mark them. */
-    if (trailer_tvb && tree) {
-      int trailer_length;
-      const guint8    *ptr;
-
-      trailer_length = tvb_length(trailer_tvb);
-      if (trailer_length > 0) {
-        ptr = tvb_get_ptr(trailer_tvb, 0, trailer_length);
-        proto_tree_add_bytes(vlan_tree, hf_vlan_trailer, trailer_tvb, 0,
-			     trailer_length, ptr);
-      }
-    }
+    dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vlan_tree,
+		  hf_vlan_len, hf_vlan_trailer);
   } else {
     ethertype(encap_proto, tvb, 4, pinfo, tree, vlan_tree,
 		       hf_vlan_etype, hf_vlan_trailer);
@@ -215,11 +166,5 @@ proto_register_vlan(void)
 void
 proto_reg_handoff_vlan(void)
 {
-  /*
-   * Get handles for the IPX and LLC dissectors.
-   */
-  llc_handle = find_dissector("llc");
-  ipx_handle = find_dissector("ipx");
-
   dissector_add("ethertype", ETHERTYPE_VLAN, dissect_vlan, proto_vlan);
 }