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Clean up the ATM dissection a bit. 

Have separate dissectors for ATM MPLS pseudo-wire traffic and regular
traffic.  That way, we can handle the regular traffic dissectors being
handed private data, e.g. an ATM pseudo-header from libwiretap.

Change-Id: I11e5abfdb1c3a5acc070ddaba8ef53813bc85e1a
Reviewed-on: https://code.wireshark.org/review/8921
Reviewed-by: Guy Harris <guy@alum.mit.edu>
This commit is contained in:
Guy Harris 2015-06-14 14:48:14 -07:00
parent 0e721578ee
commit 6625cf5e52
2 changed files with 164 additions and 140 deletions
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298
epan/dissectors/packet-atm.c
View File

@ -1353,136 +1353,18 @@ static const value_string ft_ad_vals[] = {
};
/*
* Check for OAM cells.
* OAM F4 is VCI 3 or 4 and PT 0X0.
* OAM F5 is PT 10X.
*/
gboolean
atm_is_oam_cell(const guint16 vci, const guint8 pt)
{
return (((vci == 3 || vci == 4) && ((pt & 0x5) == 0))
|| ((pt & 0x6) == 0x4));
}
static void
dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
proto_tree *atm_tree, guint aal, gboolean nni,
gboolean crc_stripped, const pwatm_private_data_t *pwpd)
dissect_atm_cell_payload(tvbuff_t *tvb, int offset, packet_info *pinfo,
proto_tree *tree, guint aal,
const pwatm_private_data_t *pwpd)
{
int offset;
proto_tree *aal_tree;
proto_item *ti;
guint8 octet, pt;
int err;
guint16 vpi, vci, aal3_4_hdr, crc10;
guint8 octet;
gint length;
guint16 aal3_4_hdr, crc10;
tvbuff_t *next_tvb;
if (NULL == pwpd) {
if (!nni) {
/*
* FF: ITU-T I.361 (Section 2.2) defines the cell header format
* and encoding at UNI reference point as:
*
* 8 7 6 5 4 3 2 1
* +-+-+-+-+-+-+-+-+
* | GFC | VPI |
* +-+-+-+-+-+-+-+-+
* | VPI | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI | PT |C|
* +-+-+-+-+-+-+-+-+
* | HEC (CRC) |
* +-+-+-+-+-+-+-+-+
*/
octet = tvb_get_guint8(tvb, 0);
proto_tree_add_item(atm_tree, hf_atm_gfc, tvb, 0, 1, ENC_NA);
vpi = (octet & 0xF) << 4;
octet = tvb_get_guint8(tvb, 1);
vpi |= octet >> 4;
proto_tree_add_uint(atm_tree, hf_atm_vpi, tvb, 0, 2, vpi);
} else {
/*
* FF: ITU-T I.361 (Section 2.3) defines the cell header format
* and encoding at NNI reference point as:
*
* 8 7 6 5 4 3 2 1
* +-+-+-+-+-+-+-+-+
* | VPI |
* +-+-+-+-+-+-+-+-+
* | VPI | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI | PT |C|
* +-+-+-+-+-+-+-+-+
* | HEC (CRC) |
* +-+-+-+-+-+-+-+-+
*/
octet = tvb_get_guint8(tvb, 0);
vpi = octet << 4;
octet = tvb_get_guint8(tvb, 1);
vpi |= (octet & 0xF0) >> 4;
proto_tree_add_uint(atm_tree, hf_atm_vpi, tvb, 0, 2, vpi);
}
vci = (octet & 0x0F) << 12;
octet = tvb_get_guint8(tvb, 2);
vci |= octet << 4;
octet = tvb_get_guint8(tvb, 3);
vci |= octet >> 4;
proto_tree_add_uint(atm_tree, hf_atm_vci, tvb, 1, 3, vci);
pt = (octet >> 1) & 0x7;
proto_tree_add_item(atm_tree, hf_atm_payload_type, tvb, 3, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(atm_tree, hf_atm_cell_loss_priority, tvb, 3, 1, ENC_BIG_ENDIAN);
if (!crc_stripped) {
/*
* FF: parse the Header Error Check (HEC).
*/
ti = proto_tree_add_item(atm_tree, hf_atm_header_error_check, tvb, 4, 1, ENC_BIG_ENDIAN);
err = get_header_err(tvb_get_ptr(tvb, 0, 5));
if (err == NO_ERROR_DETECTED)
proto_item_append_text(ti, " (correct)");
else if (err == UNCORRECTIBLE_ERROR)
proto_item_append_text(ti, " (uncorrectable error)");
else
proto_item_append_text(ti, " (error in bit %d)", err);
offset = 5;
} else {
/*
* FF: in some encapsulation modes (e.g. RFC 4717, ATM N-to-One
* Cell Mode) the Header Error Check (HEC) field is stripped.
* So we do nothing here.
*/
offset = 4;
}
}
else
{
offset = 0; /* For PWs. Header is decoded by PW dissector.*/
/* Not used !
vpi = pwpd->vpi;
*/
vci = pwpd->vci;
pt = pwpd->pti;
}
/*
* Check for OAM cells.
* XXX - do this for all AAL values, overriding whatever information
* Wiretap got from the file?
*/
if (aal == AAL_USER || aal == AAL_UNKNOWN) {
if (atm_is_oam_cell(vci,pt)) {
aal = AAL_OAMCELL;
}
}
switch (aal) {
case AAL_1:
@ -1583,6 +1465,125 @@ dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
}
}
/*
* Check for OAM cells.
* OAM F4 is VCI 3 or 4 and PT 0X0.
* OAM F5 is PT 10X.
*/
gboolean
atm_is_oam_cell(const guint16 vci, const guint8 pt)
{
return (((vci == 3 || vci == 4) && ((pt & 0x5) == 0))
|| ((pt & 0x6) == 0x4));
}
static void
dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
proto_tree *atm_tree, guint aal, gboolean nni,
gboolean crc_stripped)
{
int offset;
proto_item *ti;
guint8 octet, pt;
int err;
guint16 vpi, vci;
if (!nni) {
/*
* FF: ITU-T I.361 (Section 2.2) defines the cell header format
* and encoding at UNI reference point as:
*
* 8 7 6 5 4 3 2 1
* +-+-+-+-+-+-+-+-+
* | GFC | VPI |
* +-+-+-+-+-+-+-+-+
* | VPI | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI | PT |C|
* +-+-+-+-+-+-+-+-+
* | HEC (CRC) |
* +-+-+-+-+-+-+-+-+
*/
octet = tvb_get_guint8(tvb, 0);
proto_tree_add_item(atm_tree, hf_atm_gfc, tvb, 0, 1, ENC_NA);
vpi = (octet & 0xF) << 4;
octet = tvb_get_guint8(tvb, 1);
vpi |= octet >> 4;
proto_tree_add_uint(atm_tree, hf_atm_vpi, tvb, 0, 2, vpi);
} else {
/*
* FF: ITU-T I.361 (Section 2.3) defines the cell header format
* and encoding at NNI reference point as:
*
* 8 7 6 5 4 3 2 1
* +-+-+-+-+-+-+-+-+
* | VPI |
* +-+-+-+-+-+-+-+-+
* | VPI | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI |
* +-+-+-+-+-+-+-+-+
* | VCI | PT |C|
* +-+-+-+-+-+-+-+-+
* | HEC (CRC) |
* +-+-+-+-+-+-+-+-+
*/
octet = tvb_get_guint8(tvb, 0);
vpi = octet << 4;
octet = tvb_get_guint8(tvb, 1);
vpi |= (octet & 0xF0) >> 4;
proto_tree_add_uint(atm_tree, hf_atm_vpi, tvb, 0, 2, vpi);
}
vci = (octet & 0x0F) << 12;
octet = tvb_get_guint8(tvb, 2);
vci |= octet << 4;
octet = tvb_get_guint8(tvb, 3);
vci |= octet >> 4;
proto_tree_add_uint(atm_tree, hf_atm_vci, tvb, 1, 3, vci);
pt = (octet >> 1) & 0x7;
proto_tree_add_item(atm_tree, hf_atm_payload_type, tvb, 3, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(atm_tree, hf_atm_cell_loss_priority, tvb, 3, 1, ENC_BIG_ENDIAN);
if (!crc_stripped) {
/*
* FF: parse the Header Error Check (HEC).
*/
ti = proto_tree_add_item(atm_tree, hf_atm_header_error_check, tvb, 4, 1, ENC_BIG_ENDIAN);
err = get_header_err(tvb_get_ptr(tvb, 0, 5));
if (err == NO_ERROR_DETECTED)
proto_item_append_text(ti, " (correct)");
else if (err == UNCORRECTIBLE_ERROR)
proto_item_append_text(ti, " (uncorrectable error)");
else
proto_item_append_text(ti, " (error in bit %d)", err);
offset = 5;
} else {
/*
* FF: in some encapsulation modes (e.g. RFC 4717, ATM N-to-One
* Cell Mode) the Header Error Check (HEC) field is stripped.
* So we do nothing here.
*/
offset = 4;
}
/*
* Check for OAM cells.
* XXX - do this for all AAL values, overriding whatever information
* Wiretap got from the file?
*/
if (aal == AAL_USER || aal == AAL_UNKNOWN) {
if (atm_is_oam_cell(vci,pt)) {
aal = AAL_OAMCELL;
}
}
dissect_atm_cell_payload(tvb, offset, pinfo, tree, aal, NULL);
}
static int
dissect_atm_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
gboolean truncated, const pwatm_private_data_t *pwpd)
@ -1651,7 +1652,7 @@ dissect_atm_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
}
dissect_atm_cell(tvb, pinfo, tree, atm_tree,
pinfo->pseudo_header->atm.aal, FALSE,
pinfo->pseudo_header->atm.flags & ATM_NO_HEC, pwpd);
pinfo->pseudo_header->atm.flags & ATM_NO_HEC);
} else {
/* This is a reassembled PDU. */
@ -1668,7 +1669,13 @@ dissect_atm_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
}
static int
dissect_atm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
dissect_atm_truncated(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
return dissect_atm_common(tvb, pinfo, tree, TRUE, NULL);
}
static int
dissect_atm_pw_truncated(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
const pwatm_private_data_t *pwpd = (const pwatm_private_data_t *)data;
@ -1676,7 +1683,13 @@ dissect_atm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
}
static int
dissect_atm_untruncated(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
dissect_atm_untruncated(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
return dissect_atm_common(tvb, pinfo, tree, FALSE, NULL);
}
static int
dissect_atm_pw_untruncated(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
const pwatm_private_data_t *pwpd = (const pwatm_private_data_t *)data;
@ -1684,21 +1697,29 @@ dissect_atm_untruncated(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
}
static int
dissect_atm_oam_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
dissect_atm_oam_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_tree *atm_tree = NULL;
proto_item *atm_ti = NULL;
const pwatm_private_data_t *pwpd = (const pwatm_private_data_t *)data;
gboolean pseudowire_mode = (NULL != pwpd);
proto_tree *atm_tree;
proto_item *atm_ti;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "ATM");
if (!pseudowire_mode) {
atm_ti = proto_tree_add_item(tree, proto_atm, tvb, 0, 0, ENC_NA);
atm_tree = proto_item_add_subtree(atm_ti, ett_atm);
}
atm_ti = proto_tree_add_item(tree, proto_atm, tvb, 0, 0, ENC_NA);
atm_tree = proto_item_add_subtree(atm_ti, ett_atm);
dissect_atm_cell(tvb, pinfo, tree, atm_tree, AAL_OAMCELL, FALSE, FALSE);
return tvb_reported_length(tvb);
}
static int
dissect_atm_pw_oam_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
const pwatm_private_data_t *pwpd = (const pwatm_private_data_t *)data;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "ATM");
dissect_atm_cell_payload(tvb, 0, pinfo, tree, AAL_OAMCELL, pwpd);
dissect_atm_cell(tvb, pinfo, tree, atm_tree, AAL_OAMCELL, FALSE, FALSE, pwpd);
return tvb_reported_length(tvb);
}
@ -1978,9 +1999,12 @@ proto_register_atm(void)
atm_type_aal2_table = register_dissector_table("atm.aal2.type", "ATM AAL_2 type subdissector", FT_UINT32, BASE_DEC);
atm_type_aal5_table = register_dissector_table("atm.aal5.type", "ATM AAL_5 type subdissector", FT_UINT32, BASE_DEC);
atm_handle = new_register_dissector("atm_truncated", dissect_atm, proto_atm);
atm_handle = new_register_dissector("atm_truncated", dissect_atm_truncated, proto_atm);
new_register_dissector("atm_pw_truncated", dissect_atm_pw_truncated, proto_atm);
atm_untruncated_handle = new_register_dissector("atm_untruncated", dissect_atm_untruncated, proto_atm);
new_register_dissector("atm_pw_untruncated", dissect_atm_pw_untruncated, proto_atm);
new_register_dissector("atm_oam_cell", dissect_atm_oam_cell, proto_oamaal);
new_register_dissector("atm_pw_oam_cell", dissect_atm_pw_oam_cell, proto_oamaal);
atm_module = prefs_register_protocol ( proto_atm, NULL );
prefs_register_bool_preference(atm_module, "dissect_lane_as_sscop", "Dissect LANE as SSCOP",

6
epan/dissectors/packet-pw-atm.c
View File

@ -1971,9 +1971,9 @@ proto_reg_handoff_pw_atm_ata(void)
dh_cell = find_dissector("mpls_pw_atm_cell");
dh_cell_header = find_dissector("mpls_pw_atm_cell_header");
dh_control_word = find_dissector("mpls_pw_atm_control_word");
dh_atm_truncated = find_dissector("atm_truncated");
dh_atm_untruncated = find_dissector("atm_untruncated");
dh_atm_oam_cell = find_dissector("atm_oam_cell");
dh_atm_truncated = find_dissector("atm_pw_truncated");
dh_atm_untruncated = find_dissector("atm_pw_untruncated");
dh_atm_oam_cell = find_dissector("atm_pw_oam_cell");
dh_padding = find_dissector("pw_padding");
dh_data = find_dissector("data");
}