Q.933 doesn't define the use of an NLPID in the payload of a Frame Relay
packet (Q.922 doesn't really do so, either, but...). Do a full dissection of the octets of the address field, don't just assume a 2-octet address field. Clear the Info column. svn path=/trunk/; revision=8333
This commit is contained in:
Guy Harris
parent
9d603ccc2c
commit
8aee4ddf4a
262
packet-fr.c
262
packet-fr.c
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@ -3,7 +3,7 @@
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*
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* Copyright 2001, Paul Ionescu <paul@acorp.ro>
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*
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* $Id: packet-fr.c,v 1.34 2003/04/29 17:56:47 guy Exp $
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* $Id: packet-fr.c,v 1.35 2003/09/02 18:33:11 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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@ -27,7 +27,7 @@
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*
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* http://www.protocols.com/pbook/frame.htm
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* http://www.frforum.com/5000/Approved/FRF.3/FRF.3.2.pdf
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* ITU Recommendation Q.933
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* ITU Recommendations Q.922 and Q.933
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* RFC-1490
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* RFC-2427
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* Cisco encapsulation
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@ -57,30 +57,38 @@
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/*
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* Bits in the address field.
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*/
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#define FRELAY_DLCI 0xfcf0 /* 2 byte DLCI Address */
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#define FRELAY_CR 0x0200 /* Command/Response bit */
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#define FRELAY_EA 0x0001 /* Address Extension bit */
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#define FRELAY_FECN 0x0008 /* Forward Explicit Congestion Notification */
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#define FRELAY_BECN 0x0004 /* Backward Explicit Congestion Notification */
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#define FRELAY_DE 0x0002 /* Discard Eligibility */
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#define FRELAY_DC 0x0002 /* Control bits */
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#define FRELAY_EA 0x01 /* Address field extension bit */
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/*
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* Extract the DLCI from the address field.
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*/
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#define EXTRACT_DLCI(addr) ((((addr)&0xfc00) >> 6) | (((addr)&0xf0) >> 4))
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#define FRELAY_UPPER_DLCI 0xFC /* Upper DLCI */
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#define FRELAY_CR 0x02 /* Command/response bit in first octet */
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#define FRELAY_SECOND_DLCI 0xF0 /* DLCI bits in FECN/BECN/DE octet */
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#define FRELAY_FECN 0x08 /* Forward Explicit Congestion Notification */
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#define FRELAY_BECN 0x04 /* Backward Explicit Congestion Notification */
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#define FRELAY_DE 0x02 /* Discard Eligibility */
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#define FRELAY_THIRD_DLCI 0xFE /* DLCI bits in third octet, if any */
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#define FRELAY_LOWER_DLCI 0xFC /* Lower DLCI */
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#define FRELAY_DC 0x02 /* DLCI or DL-CORE control indicator in last octet */
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#define FROM_DCE 0x80 /* for direction setting */
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static gint proto_fr = -1;
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static gint ett_fr = -1;
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static gint hf_fr_dlci = -1;
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static gint hf_fr_cr = -1;
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static gint hf_fr_becn = -1;
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static gint hf_fr_fecn = -1;
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static gint hf_fr_de = -1;
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static gint ett_fr_address = -1;
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static gint hf_fr_ea = -1;
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static gint hf_fr_upper_dlci = -1;
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static gint hf_fr_cr = -1;
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static gint hf_fr_second_dlci = -1;
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static gint hf_fr_fecn = -1;
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static gint hf_fr_becn = -1;
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static gint hf_fr_de = -1;
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static gint hf_fr_third_dlci = -1;
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static gint hf_fr_dlcore_control = -1;
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static gint hf_fr_lower_dlci = -1;
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static gint hf_fr_dc = -1;
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static gint hf_fr_dlci = -1;
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static gint hf_fr_nlpid = -1;
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static gint hf_fr_oui = -1;
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static gint hf_fr_pid = -1;
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@ -141,15 +149,20 @@ static void dissect_fr_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
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static void dissect_fr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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int offset = 0;
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proto_item *ti = NULL;
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proto_tree *fr_tree = NULL;
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guint16 fr_header,fr_type,offset=2; /* default header length of FR is 2 bytes */
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guint16 address;
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char buf[32];
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proto_item *octet_item = NULL;
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proto_tree *octet_tree = NULL;
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guint8 fr_octet;
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guint32 address;
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guint8 fr_ctrl;
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guint16 fr_type;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "FR");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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if (pinfo->pseudo_header->x25.flags & FROM_DCE) {
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if(check_col(pinfo->cinfo, COL_RES_DL_DST))
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@ -164,34 +177,137 @@ static void dissect_fr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
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}
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/*XXX We should check the EA bits and use that to generate the address. */
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/*
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* OK, fetch the address field - keep going until we get an EA bit.
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*/
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fr_octet = tvb_get_guint8(tvb, offset);
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, -1, "Frame Relay");
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fr_tree = proto_item_add_subtree(ti, ett_fr);
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}
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if (fr_octet & FRELAY_EA) {
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/*
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* Bogus! There should be at least 2 octets.
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*/
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address = 0;
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if (tree) {
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proto_tree_add_text(fr_tree, tvb, offset, 1,
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"Bogus 1-octet address field");
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offset++;
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}
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} else {
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/*
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* The first octet contains the upper 6 bits of the DLCI, as well
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* as the C/R bit.
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*/
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address = (fr_octet & 0xFC) >> 2;
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if (tree) {
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octet_item = proto_tree_add_text(fr_tree, tvb, offset, 1,
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"First address octet: 0x%02x", fr_octet);
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octet_tree = proto_item_add_subtree(octet_item, ett_fr_address);
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proto_tree_add_uint(octet_tree, hf_fr_upper_dlci, tvb, offset, 1, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_cr, tvb, offset, 1, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_ea, tvb, offset, 1, fr_octet);
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}
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offset++;
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/*
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* The second octet contains 4 more bits of DLCI, as well as FECN,
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* BECN, and DE.
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*/
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fr_octet = tvb_get_guint8(tvb, offset);
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address = (address << 4) | ((fr_octet & 0xF0) >> 4);
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if (tree) {
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octet_item = proto_tree_add_text(fr_tree, tvb, offset, 1,
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"Second address octet: 0x%02x",
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fr_octet);
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octet_tree = proto_item_add_subtree(octet_item, ett_fr_address);
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proto_tree_add_uint(octet_tree, hf_fr_second_dlci, tvb, offset, 1, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_fecn, tvb, 0, offset, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_becn, tvb, 0, offset, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_de, tvb, 0, offset, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_ea, tvb, offset, 1, fr_octet);
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}
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offset++;
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if (!(fr_octet & FRELAY_EA)) {
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/*
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* We have 3 or more address octets.
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*
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* The third octet contains 7 more bits of DLCI if EA isn't set,
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* and lower DLCI or DL-CORE control plus the DLCI or DL-CORE
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* control indicator flag if EA is set.
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*/
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fr_octet = tvb_get_guint8(tvb, offset);
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if (!(fr_octet & FRELAY_EA)) {
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/*
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* 7 more bits of DLCI.
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*/
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address = (address << 7) | ((fr_octet & 0xFE) >> 1);
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if (tree) {
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octet_item = proto_tree_add_text(fr_tree, tvb, offset, 1,
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"Third address octet: 0x%02x",
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fr_octet);
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octet_tree = proto_item_add_subtree(octet_item, ett_fr_address);
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proto_tree_add_uint(octet_tree, hf_fr_third_dlci, tvb, offset, 1, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_ea, tvb, offset, 1, fr_octet);
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}
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offset++;
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fr_octet = tvb_get_guint8(tvb, offset);
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while (!(fr_octet & FRELAY_EA)) {
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/*
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* Bogus! More than 4 octets of address.
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*/
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if (tree) {
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proto_tree_add_text(fr_tree, tvb, offset, 1,
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"Bogus extra address octet");
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}
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offset++;
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fr_octet = tvb_get_guint8(tvb, offset);
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}
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}
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if (tree) {
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octet_item = proto_tree_add_text(fr_tree, tvb, offset, 1,
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"Final address octet: 0x%02x",
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fr_octet);
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octet_tree = proto_item_add_subtree(octet_item, ett_fr_address);
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}
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/*
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* Last octet - contains lower DLCI or DL-CORE control, DLCI or
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* DL-CORE control indicator flag.
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*/
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if (fr_octet & FRELAY_DC) {
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/*
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* DL-CORE.
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*/
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proto_tree_add_uint(octet_tree, hf_fr_dlcore_control, tvb, offset, 1, fr_octet);
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} else {
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/*
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* Last 6 bits of DLCI.
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*/
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address = (address << 6) | ((fr_octet & 0xFC) >> 2);
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proto_tree_add_uint(octet_tree, hf_fr_lower_dlci, tvb, offset, 1, fr_octet);
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}
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proto_tree_add_boolean(octet_tree, hf_fr_dc, tvb, offset, 1, fr_octet);
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proto_tree_add_boolean(octet_tree, hf_fr_ea, tvb, offset, 1, fr_octet);
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}
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}
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if (tree) {
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/* Put the full DLCI into the protocol tree. */
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proto_tree_add_uint(fr_tree, hf_fr_dlci, tvb, 0, offset, address);
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}
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fr_header = tvb_get_ntohs(tvb, 0);
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fr_ctrl = tvb_get_guint8( tvb, 2);
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address = EXTRACT_DLCI(fr_header);
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pinfo->ctype = CT_DLCI;
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pinfo->circuit_id = address;
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if (check_col(pinfo->cinfo, COL_INFO))
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col_add_fstr(pinfo->cinfo, COL_INFO, "DLCI %u", address);
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, 3, "Frame Relay");
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fr_tree = proto_item_add_subtree(ti, ett_fr);
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decode_bitfield_value(buf, fr_header, FRELAY_DLCI, 16);
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proto_tree_add_uint_format(fr_tree, hf_fr_dlci, tvb, 0, 2, address,
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"%sDLCI: %u", buf, address);
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proto_tree_add_boolean(fr_tree, hf_fr_cr, tvb, 0, offset, fr_header);
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proto_tree_add_boolean(fr_tree, hf_fr_fecn, tvb, 0, offset, fr_header);
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proto_tree_add_boolean(fr_tree, hf_fr_becn, tvb, 0, offset, fr_header);
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proto_tree_add_boolean(fr_tree, hf_fr_de, tvb, 0, offset, fr_header);
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proto_tree_add_boolean(fr_tree, hf_fr_ea, tvb, 0, offset, fr_header);
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}
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fr_ctrl = tvb_get_guint8(tvb, offset);
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if (fr_ctrl == XDLC_U) {
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if (tree) {
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proto_tree_add_text(fr_tree, tvb, offset, 0, "------- Q.933 Encapsulation -------");
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proto_tree_add_text(fr_tree, tvb, offset, 0, "------- Q.922 Encapsulation -------");
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/*
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* XXX - if we're going to show this as Unnumbered
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* Information, should we just hand it to
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@ -225,7 +341,7 @@ static void dissect_fr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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if (ti != NULL) {
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/* Include the Cisco HDLC type in the top-level protocol
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tree item. */
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proto_item_set_len(ti, offset+2);
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proto_item_set_end(ti, tvb, offset+2);
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}
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chdlctype(fr_type, tvb, offset+2, pinfo, tree, fr_tree, hf_fr_chdlctype);
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}
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@ -244,7 +360,7 @@ static void dissect_fr_uncompressed(tvbuff_t *tvb, packet_info *pinfo,
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col_clear(pinfo->cinfo, COL_INFO);
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, 4, "Frame Relay");
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ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, -1, "Frame Relay");
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fr_tree = proto_item_add_subtree(ti, ett_fr);
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}
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dissect_fr_nlpid(tvb, 0, pinfo, tree, ti, fr_tree, XDLC_U);
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@ -257,6 +373,12 @@ static void dissect_fr_nlpid(tvbuff_t *tvb, int offset, packet_info *pinfo,
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guint8 fr_nlpid;
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tvbuff_t *next_tvb;
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/*
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* Tentatively set the Frame Relay item not to include the NLPID,
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* as OSI network layer protocols consider it to be part of
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* the OSI PDU.
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*/
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proto_item_set_end(ti, tvb, offset);
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fr_nlpid = tvb_get_guint8 (tvb,offset);
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if (fr_nlpid == 0) {
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if (tree)
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@ -264,7 +386,7 @@ static void dissect_fr_nlpid(tvbuff_t *tvb, int offset, packet_info *pinfo,
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offset++;
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if (ti != NULL) {
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/* Include the padding in the top-level protocol tree item. */
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proto_item_set_len(ti, offset);
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proto_item_set_end(ti, tvb, offset);
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}
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fr_nlpid=tvb_get_guint8( tvb,offset);
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}
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@ -333,7 +455,7 @@ static void dissect_fr_nlpid(tvbuff_t *tvb, int offset, packet_info *pinfo,
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if (ti != NULL) {
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/* Include the NLPID and SNAP header in the top-level
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protocol tree item. */
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proto_item_set_len(ti, offset+5);
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proto_item_set_end(ti, tvb, offset+5);
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}
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dissect_snap(tvb, offset, pinfo, tree, fr_tree, fr_ctrl,
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hf_fr_oui, hf_fr_snaptype, hf_fr_pid, 0);
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@ -342,7 +464,7 @@ static void dissect_fr_nlpid(tvbuff_t *tvb, int offset, packet_info *pinfo,
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default:
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if (ti != NULL) {
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/* Include the NLPID in the top-level protocol tree item. */
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proto_item_set_len(ti, offset);
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proto_item_set_end(ti, tvb, offset);
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}
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next_tvb = tvb_new_subset(tvb,offset,-1,-1);
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if (!dissector_try_port(fr_subdissector_table,fr_nlpid,
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@ -367,29 +489,42 @@ static void dissect_fr_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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void proto_register_fr(void)
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{
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static hf_register_info hf[] = {
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{ &hf_fr_dlci, {
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"DLCI", "fr.dlci", FT_UINT16, BASE_DEC,
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NULL, FRELAY_DLCI, "Data-Link Connection Identifier", HFILL }},
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{ &hf_fr_ea, {
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"EA", "fr.ea", FT_BOOLEAN, 8, TFS(&ea_string),
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FRELAY_EA, "Extended Address", HFILL }},
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{ &hf_fr_upper_dlci, {
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"Upper DLCI", "fr.upper_dlci", FT_UINT8, BASE_HEX,
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NULL, FRELAY_UPPER_DLCI, "Upper bits of DLCI", HFILL }},
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{ &hf_fr_cr, {
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"CR", "fr.cr", FT_BOOLEAN, 16, TFS(&cmd_string),
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"CR", "fr.cr", FT_BOOLEAN, 8, TFS(&cmd_string),
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FRELAY_CR, "Command/Response", HFILL }},
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{ &hf_fr_second_dlci, {
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"Second DLCI", "fr.second_dlci", FT_UINT8, BASE_HEX,
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NULL, FRELAY_SECOND_DLCI, "Bits below upper bits of DLCI", HFILL }},
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{ &hf_fr_fecn, {
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"FECN", "fr.fecn", FT_BOOLEAN, 8,
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NULL, FRELAY_FECN, "Forward Explicit Congestion Notification", HFILL }},
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{ &hf_fr_becn, {
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"BECN", "fr.becn", FT_BOOLEAN, 8,
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NULL, FRELAY_BECN, "Backward Explicit Congestion Notification", HFILL }},
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{ &hf_fr_de, {
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"DE", "fr.de", FT_BOOLEAN, 8,
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NULL, FRELAY_DE, "Discard Eligibility", HFILL }},
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{ &hf_fr_third_dlci, {
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"Third DLCI", "fr.third_dlci", FT_UINT8, BASE_HEX,
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NULL, FRELAY_THIRD_DLCI, "Additional bits of DLCI", HFILL }},
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{ &hf_fr_dlcore_control, {
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"DL-CORE Control", "fr.dlcore_control", FT_UINT8, BASE_HEX,
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NULL, FRELAY_LOWER_DLCI, "DL-Core control bits", HFILL }},
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{ &hf_fr_lower_dlci, {
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"Lower DLCI", "fr.lower_dlci", FT_UINT8, BASE_HEX,
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NULL, FRELAY_LOWER_DLCI, "Lower bits of DLCI", HFILL }},
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{ &hf_fr_dc, {
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"DC", "fr.dc", FT_BOOLEAN, 16, TFS(&ctrl_string),
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FRELAY_CR, "Address/Control", HFILL }},
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{ &hf_fr_fecn, {
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"FECN", "fr.fecn", FT_BOOLEAN, 16,
|
||||
NULL, FRELAY_FECN, "Forward Explicit Congestion Notification", HFILL }},
|
||||
{ &hf_fr_becn, {
|
||||
"BECN", "fr.becn", FT_BOOLEAN, 16,
|
||||
NULL, FRELAY_BECN, "Backward Explicit Congestion Notification", HFILL }},
|
||||
{ &hf_fr_de, {
|
||||
"DE", "fr.de", FT_BOOLEAN, 16,
|
||||
NULL, FRELAY_DE, "Discard Eligibility", HFILL }},
|
||||
{ &hf_fr_ea, {
|
||||
"EA", "fr.ea", FT_BOOLEAN, 16, TFS(&ea_string),
|
||||
FRELAY_EA, "Extended Address", HFILL }},
|
||||
{ &hf_fr_dlci, {
|
||||
"DLCI", "fr.dlci", FT_UINT32, BASE_DEC,
|
||||
NULL, 0x0, "Data-Link Connection Identifier", HFILL }},
|
||||
{ &hf_fr_nlpid, {
|
||||
"NLPID", "fr.nlpid", FT_UINT8, BASE_HEX,
|
||||
VALS(fr_nlpid_vals), 0x0, "FrameRelay Encapsulated Protocol NLPID", HFILL }},
|
||||
|
|
@ -411,6 +546,7 @@ void proto_register_fr(void)
|
|||
/* Setup protocol subtree array */
|
||||
static gint *ett[] = {
|
||||
&ett_fr,
|
||||
&ett_fr_address,
|
||||
};
|
||||
|
||||
proto_fr = proto_register_protocol("Frame Relay", "FR", "fr");
|
||||
|
|
|
|||
Loading…
Reference in New Issue