/* packet-vlan.c
* Routines for VLAN 802.1Q ethernet header disassembly
*
- * $Id: packet-vlan.c,v 1.12 2000/05/11 22:04:17 gram Exp $
+ * $Id: packet-vlan.c,v 1.28 2001/01/09 06:31:44 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
#include "etypes.h"
static int proto_vlan = -1;
-static int hf_vlan_etype = -1;
static int hf_vlan_priority = -1;
-static int hf_vlan_id = -1;
static int hf_vlan_cfi = -1;
+static int hf_vlan_id = -1;
+static int hf_vlan_etype = -1;
+static int hf_vlan_len = -1;
+static int hf_vlan_trailer = -1;
static gint ett_vlan = -1;
+static dissector_handle_t llc_handle;
+
void
capture_vlan(const u_char *pd, int offset, packet_counts *ld ) {
guint32 encap_proto;
}
static void
-dissect_vlan(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
- proto_tree *ti, *vlan_tree = NULL;
+dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+ proto_tree *ti;
guint16 tci,encap_proto;
- tvbuff_t *next_tvb;
+ volatile gboolean is_802_2;
+ tvbuff_t *volatile next_tvb;
+ tvbuff_t *volatile trailer_tvb;
+ proto_tree *volatile vlan_tree;
+ guint length_before, length;
- if (!BYTES_ARE_IN_FRAME(offset, 2*sizeof(guint16))) {
- return;
- }
+ CHECK_DISPLAY_AS_DATA(proto_vlan, tvb, pinfo, tree);
- if (check_col(fd, COL_PROTOCOL))
- col_add_str(fd, COL_PROTOCOL, "VLAN");
+ pinfo->current_proto = "VLAN";
- tci = pntohs( &pd[offset] );
- encap_proto = pntohs( &pd[offset+2] );
+ if (check_col(pinfo->fd, COL_PROTOCOL))
+ col_set_str(pinfo->fd, COL_PROTOCOL, "VLAN");
- if (check_col(fd, COL_INFO)) {
- col_add_fstr(fd, COL_INFO, "PRI: %d CFI: %d ID: %d",
+ tci = tvb_get_ntohs( tvb, 0 );
+ encap_proto = tvb_get_ntohs( tvb, 2 );
+
+ if (check_col(pinfo->fd, COL_INFO)) {
+ col_add_fstr(pinfo->fd, COL_INFO, "PRI: %d CFI: %d ID: %d",
(tci >> 13), ((tci >> 12) & 1), (tci & 0xFFF));
}
+ vlan_tree = NULL;
+
if (tree) {
- ti = proto_tree_add_item(tree, proto_vlan, NullTVB, offset, 4);
+ ti = proto_tree_add_item(tree, proto_vlan, tvb, 0, 4, FALSE);
vlan_tree = proto_item_add_subtree(ti, ett_vlan);
- proto_tree_add_item(vlan_tree, hf_vlan_priority, NullTVB, offset, 2, tci);
- proto_tree_add_item(vlan_tree, hf_vlan_cfi, NullTVB, offset, 2, tci);
- proto_tree_add_item(vlan_tree, hf_vlan_id, NullTVB, offset, 2, tci);
+ proto_tree_add_uint(vlan_tree, hf_vlan_priority, tvb, 0, 2, tci);
+ proto_tree_add_uint(vlan_tree, hf_vlan_cfi, tvb, 0, 2, tci);
+ proto_tree_add_uint(vlan_tree, hf_vlan_id, tvb, 0, 2, tci);
}
- next_tvb = tvb_new_subset(pi.compat_top_tvb, offset+4, -1);
if ( encap_proto <= IEEE_802_3_MAX_LEN) {
- if ( pd[offset+4] == 0xff && pd[offset+5] == 0xff ) {
- dissect_ipx(pd,offset+4,fd,tree);
- } else {
- dissect_llc(next_tvb, &pi, tree);
+ /* 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;
+
+ /* 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.
+ (IPX/SPX is they only thing that can be contained inside a
+ straight 802.3 packet, so presumably the same applies for
+ Ethernet VLAN packets). A non-0xffff value means that there's an
+ 802.2 layer inside the VLAN layer */
+ is_802_2 = TRUE;
+ TRY {
+ if (tvb_get_ntohs(next_tvb, 2) == 0xffff) {
+ is_802_2 = FALSE;
+ }
+ }
+ CATCH2(BoundsError, ReportedBoundsError) {
+ ; /* do nothing */
+
+ }
+ ENDTRY;
+ if (is_802_2 ) {
+ /* 802.2 LLC */
+ call_dissector(llc_handle, next_tvb, pinfo, tree);
+ } else {
+ dissect_ipx(next_tvb, pinfo, tree);
}
} else {
- ethertype(encap_proto, offset+4, pd, fd, tree, vlan_tree, hf_vlan_etype);
+ length_before = tvb_reported_length(tvb);
+ length = ethertype(encap_proto, tvb, 4, pinfo, tree, vlan_tree,
+ hf_vlan_etype) + 4;
+ if (length < length_before) {
+ /*
+ * Create a tvbuff for the padding.
+ */
+ TRY {
+ trailer_tvb = tvb_new_subset(tvb, length, -1, -1);
+ }
+ CATCH2(BoundsError, ReportedBoundsError) {
+ /* The packet doesn't have "length" bytes worth of captured
+ data left in it. No trailer to display. */
+ trailer_tvb = NULL;
+ }
+ ENDTRY;
+ } else {
+ /* No padding. */
+ trailer_tvb = NULL;
+ }
+ }
+
+ /* 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);
+ }
}
}
proto_register_vlan(void)
{
static hf_register_info hf[] = {
- { &hf_vlan_etype, {
- "Type", "vlan.etype", FT_UINT16, BASE_HEX,
- VALS(etype_vals), 0x0, "Type" }},
{ &hf_vlan_priority, {
"Priority", "vlan.priority", FT_UINT16, BASE_BIN,
0, 0xE000, "Priority" }},
{ &hf_vlan_cfi, {
"CFI", "vlan.cfi", FT_UINT16, BASE_BIN,
- 0, 0x1000, "CFI" }},
+ 0, 0x1000, "CFI" }}, /* XXX - Boolean? */
{ &hf_vlan_id, {
"ID", "vlan.id", FT_UINT16, BASE_BIN,
0, 0x0FFF, "ID" }},
+ { &hf_vlan_etype, {
+ "Type", "vlan.etype", FT_UINT16, BASE_HEX,
+ VALS(etype_vals), 0x0, "Type" }},
+ { &hf_vlan_len, {
+ "Length", "vlan.len", FT_UINT16, BASE_DEC,
+ NULL, 0x0, "Length" }},
+ { &hf_vlan_trailer, {
+ "Trailer", "vlan.trailer", FT_BYTES, BASE_NONE,
+ NULL, 0x0, "VLAN Trailer" }}
};
static gint *ett[] = {
&ett_vlan,
};
- proto_vlan = proto_register_protocol("802.1q Virtual LAN", "vlan");
+ proto_vlan = proto_register_protocol("802.1q Virtual LAN", "VLAN", "vlan");
proto_register_field_array(proto_vlan, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_vlan(void)
{
- dissector_add("ethertype", ETHERTYPE_VLAN, dissect_vlan);
+ /*
+ * Get a handle for the LLC dissector.
+ */
+ llc_handle = find_dissector("llc");
+
+ dissector_add("ethertype", ETHERTYPE_VLAN, dissect_vlan, proto_vlan);
}
git.samba.org / obnox / wireshark / wip.git / blobdiff