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Fix for Bug 3116 

wrong decoding IMSI with GSM MAP protocol

svn path=/trunk/; revision=31764
This commit is contained in:
Gerasimos Dimitriadis 2010-02-01 21:19:56 +00:00
parent f1e8ec9007
commit ba32bc6d54
5 changed files with 98 additions and 4 deletions
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2
asn1/gsm_map/packet-gsm_map-template.c
View File

@ -738,7 +738,7 @@ dissect_gsm_map_msisdn(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
if ((na == 1) && (np==1))/*International Number & E164*/
dissect_e164_cc(tvb, tree, 1, TRUE);
else if(np==6)
dissect_e212_mcc_mnc(tvb, pinfo, tree, 1);
dissect_e212_mcc_mnc_in_address(tvb, pinfo, tree, 1);
}

96
epan/dissectors/packet-e212.c
View File

@ -133,6 +133,7 @@ const value_string E212_codes[] = {
{ 401, "Kazakhstan (Republic of)" },
{ 402, "Bhutan (Kingdom of)" },
{ 404, "India (Republic of)" },
{ 405, "India (Republic of)" },
{ 410, "Pakistan (Islamic Republic of)" },
{ 412, "Afghanistan" },
{ 413, "Sri Lanka (Democratic Socialist Republic of)" },
@ -1604,8 +1605,6 @@ static int hf_E212_msin = -1;
* | MNC digit 2 | MNC digit 1 | octet x+2
* +---------------+---------------+
*/
int
dissect_e212_mcc_mnc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset){
@ -1650,6 +1649,99 @@ dissect_e212_mcc_mnc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int of
return offset;
}
/*
* When we want to decode the MCC/MNC pair in an address that is encoded according to E.212
* the main problem is that we do not know whether we are dealing with a length 2 or length 3
* MNC. Initially, it was possible to find the length of the MNC by checking the MCC code.
* Originally each country employed a pure 2 digit or 3 digit MNC scheme. However, it is possible
* to find countries now that employ both lengths for the MNC (e.g. Canada, India).
* Since in these cases we can be sure that an MNC cannot possible be a prefix for another MNC, we
* initially assume that the MNC is 2 digits long. If the MCC/MNC combination gives a match in our
* mcc_mnc_codes list then we can be sure that we deal with an MNC that is 2 digits long. Otherwise,
* assume that the MNC is 3 digits long.
*
* MNC of length 2:
*
* 8 7 6 5 4 3 2 1
* +---+---+---+---+---+---+---+---+
* | MCC digit 2 | MCC digit 1 | octet x
* +---------------+---------------+
* | MNC digit 1 | MCC digit 3 | octet x+1
* +---------------+---------------+
* | addr digit 1 | MNC digit 2 | octet x+2
* +---------------+---------------+
*
* MNC of length 3:
*
* 8 7 6 5 4 3 2 1
* +---+---+---+---+---+---+---+---+
* | MCC digit 2 | MCC digit 1 | octet x
* +---------------+---------------+
* | MNC digit 1 | MCC digit 3 | octet x+1
* +---------------+---------------+
* | MNC digit 3 | MNC digit 2 | octet x+2
* +---------------+---------------+
*
* This function will consume either 2.5 or 3 octets. For this reason it returns
* the number of nibbles consumed, i.e. 5 or 6 (2 or 3 digits long MNC respectively)
*/
int
dissect_e212_mcc_mnc_in_address(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset)
{
guint32 start_offset;
guint8 octet;
guint16 mcc, mnc;
guint8 mcc1, mcc2, mcc3, mnc1, mnc2, mnc3;
proto_item *item;
gboolean long_mnc;
long_mnc = FALSE;
start_offset = offset;
/* MCC digits 1 and 2 */
octet = tvb_get_guint8(tvb,offset);
mcc1 = octet & 0x0f;
mcc2 = octet >> 4;
offset++;
/* MCC digit 3 and MNC digit 1 */
octet = tvb_get_guint8(tvb,offset);
mcc3 = octet & 0x0f;
mnc1 = octet >> 4;
offset++;
/* MNC digits 2 and 3 */
octet = tvb_get_guint8(tvb,offset);
mnc2 = octet & 0x0f;
mnc3 = octet >> 4;
mcc = 100 * mcc1 + 10 * mcc2 + mcc3;
mnc = 10 * mnc1 + mnc2;
/* Try to match the MCC and 2 digits MNC with an entry in our list of operators */
if (!match_strval(mcc * 1000 + mnc, mcc_mnc_codes)) {
mnc = 10 * mnc + mnc3;
long_mnc = TRUE;
}
item = proto_tree_add_uint(tree, hf_E212_mcc , tvb, start_offset, 2, mcc );
if ((mcc1 > 9) || (mcc2 > 9) || (mcc3 > 9))
expert_add_info_format(pinfo, item, PI_MALFORMED, PI_WARN, "MCC contains non-decimal digits");
item = proto_tree_add_uint_format(tree, hf_E212_mnc , tvb, start_offset + 1, 2, mnc,
"Mobile Network Code (MNC): %s (%u)",
val_to_str(mcc * 1000 + mnc, mcc_mnc_codes, "Unknown"),
mnc);
if ((mnc1 > 9) || (mnc2 > 9) || (long_mnc && (mnc3 > 9)))
expert_add_info_format(pinfo, item, PI_MALFORMED, PI_WARN, "MNC contains non-decimal digits");
if(long_mnc)
return 6;
else
return 5;
}
/*
* Register the protocol with Wireshark.
*

1
epan/dissectors/packet-e212.h
View File

@ -31,6 +31,7 @@
extern const value_string E212_codes[];
int dissect_e212_mcc_mnc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset);
int dissect_e212_mcc_mnc_in_address(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset);
#endif /* __PACKET_E212_H__ */

2
epan/dissectors/packet-gsm_map.c
View File

@ -2699,7 +2699,7 @@ dissect_gsm_map_msisdn(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
if ((na == 1) && (np==1))/*International Number & E164*/
dissect_e164_cc(tvb, tree, 1, TRUE);
else if(np==6)
dissect_e212_mcc_mnc(tvb, pinfo, tree, 1);
dissect_e212_mcc_mnc_in_address(tvb, pinfo, tree, 1);
}

1
epan/libwireshark.def
View File

@ -226,6 +226,7 @@ dissect_dcom_VARIANT
dissect_dcom_VARTYPE
dissect_e164_cc
dissect_e212_mcc_mnc
dissect_e212_mcc_mnc_in_address
dissect_gsm_map_GlobalCellId
dissect_gsm_map_IMSI
dissect_gsm_map_ISDN_AddressString