Common library for all Osmocom projects (libosmocore, libosmogsm, libosmovty, libosmogb, libosmosim, libosmousb, ...) https://osmocom.org/projects/libosmocore
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libosmocore/src/gsm/gsm0480.c

461 lines
11 KiB

/* Format functions for GSM 04.80 */
/*
* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2009 by Mike Haben <michael.haben@btinternet.com>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <osmocore/gsm0480.h>
#include <osmocore/gsm_utils.h>
#include <osmocore/logging.h>
#include <osmocore/protocol/gsm_04_08.h>
#include <osmocore/protocol/gsm_04_80.h>
#include <string.h>
static inline unsigned char *msgb_wrap_with_TL(struct msgb *msgb, uint8_t tag)
{
uint8_t *data = msgb_push(msgb, 2);
data[0] = tag;
data[1] = msgb->len - 2;
return data;
}
static inline unsigned char *msgb_push_TLV1(struct msgb *msgb, uint8_t tag,
uint8_t value)
{
uint8_t *data = msgb_push(msgb, 3);
data[0] = tag;
data[1] = 1;
data[2] = value;
return data;
}
/* wrap an invoke around it... the other way around
*
* 1.) Invoke Component tag
* 2.) Invoke ID Tag
* 3.) Operation
* 4.) Data
*/
int gsm0480_wrap_invoke(struct msgb *msg, int op, int link_id)
{
/* 3. operation */
msgb_push_TLV1(msg, GSM0480_OPERATION_CODE, op);
/* 2. invoke id tag */
msgb_push_TLV1(msg, GSM0480_COMPIDTAG_INVOKE_ID, link_id);
/* 1. component tag */
msgb_wrap_with_TL(msg, GSM0480_CTYPE_INVOKE);
return 0;
}
/* wrap the GSM 04.08 Facility IE around it */
int gsm0480_wrap_facility(struct msgb *msg)
{
msgb_wrap_with_TL(msg, GSM0480_IE_FACILITY);
return 0;
}
struct msgb *gsm0480_create_unstructuredSS_Notify(int alertPattern, const char *text)
{
struct msgb *msg;
uint8_t *seq_len_ptr, *ussd_len_ptr, *data;
int len;
msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
if (!msg)
return NULL;
/* SEQUENCE { */
msgb_put_u8(msg, GSM_0480_SEQUENCE_TAG);
seq_len_ptr = msgb_put(msg, 1);
/* DCS { */
msgb_put_u8(msg, ASN1_OCTET_STRING_TAG);
msgb_put_u8(msg, 1);
msgb_put_u8(msg, 0x0F);
/* } DCS */
/* USSD-String { */
msgb_put_u8(msg, ASN1_OCTET_STRING_TAG);
ussd_len_ptr = msgb_put(msg, 1);
data = msgb_put(msg, 0);
len = gsm_7bit_encode(data, text);
msgb_put(msg, len);
ussd_len_ptr[0] = len;
/* USSD-String } */
/* alertingPattern { */
msgb_put_u8(msg, ASN1_OCTET_STRING_TAG);
msgb_put_u8(msg, 1);
msgb_put_u8(msg, alertPattern);
/* } alertingPattern */
seq_len_ptr[0] = 3 + 2 + ussd_len_ptr[0] + 3;
/* } SEQUENCE */
return msg;
}
struct msgb *gsm0480_create_notifySS(const char *text)
{
struct msgb *msg;
uint8_t *data, *tmp_len;
uint8_t *seq_len_ptr, *cal_len_ptr, *opt_len_ptr, *nam_len_ptr;
int len;
len = strlen(text);
if (len < 1 || len > 160)
return NULL;
msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
if (!msg)
return NULL;
msgb_put_u8(msg, GSM_0480_SEQUENCE_TAG);
seq_len_ptr = msgb_put(msg, 1);
/* ss_code for CNAP { */
msgb_put_u8(msg, 0x81);
msgb_put_u8(msg, 1);
msgb_put_u8(msg, 0x19);
/* } ss_code */
/* nameIndicator { */
msgb_put_u8(msg, 0xB4);
nam_len_ptr = msgb_put(msg, 1);
/* callingName { */
msgb_put_u8(msg, 0xA0);
opt_len_ptr = msgb_put(msg, 1);
msgb_put_u8(msg, 0xA0);
cal_len_ptr = msgb_put(msg, 1);
/* namePresentationAllowed { */
/* add the DCS value */
msgb_put_u8(msg, 0x80);
msgb_put_u8(msg, 1);
msgb_put_u8(msg, 0x0F);
/* add the lengthInCharacters */
msgb_put_u8(msg, 0x81);
msgb_put_u8(msg, 1);
msgb_put_u8(msg, strlen(text));
/* add the actual string */
msgb_put_u8(msg, 0x82);
tmp_len = msgb_put(msg, 1);
data = msgb_put(msg, 0);
len = gsm_7bit_encode(data, text);
tmp_len[0] = len;
msgb_put(msg, len);
/* }; namePresentationAllowed */
cal_len_ptr[0] = 3 + 3 + 2 + len;
opt_len_ptr[0] = cal_len_ptr[0] + 2;
/* }; callingName */
nam_len_ptr[0] = opt_len_ptr[0] + 2;
/* ); nameIndicator */
/* write the lengths... */
seq_len_ptr[0] = 3 + nam_len_ptr[0] + 2;
return msg;
}
/* Forward declarations */
static int parse_ussd(const struct gsm48_hdr *hdr,
uint16_t len, struct ussd_request *req);
static int parse_ussd_info_elements(const uint8_t *ussd_ie, uint16_t len,
struct ussd_request *req);
static int parse_facility_ie(const uint8_t *facility_ie, uint16_t length,
struct ussd_request *req);
static int parse_ss_invoke(const uint8_t *invoke_data, uint16_t length,
struct ussd_request *req);
static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length,
struct ussd_request *req);
/* Decode a mobile-originated USSD-request message */
int gsm0480_decode_ussd_request(const struct gsm48_hdr *hdr, uint16_t len,
struct ussd_request *req)
{
int rc = 0;
if (len < sizeof(*hdr) + 2) {
LOGP(0, LOGL_DEBUG, "USSD Request is too short.\n");
return 0;
}
if ((hdr->proto_discr & 0x0f) == GSM48_PDISC_NC_SS) {
req->transaction_id = hdr->proto_discr & 0x70;
rc = parse_ussd(hdr, len, req);
}
if (!rc)
LOGP(0, LOGL_DEBUG, "Error occurred while parsing received USSD!\n");
return rc;
}
static int parse_ussd(const struct gsm48_hdr *hdr, uint16_t len, struct ussd_request *req)
{
int rc = 1;
uint8_t msg_type = hdr->msg_type & 0xBF; /* message-type - section 3.4 */
switch (msg_type) {
case GSM0480_MTYPE_RELEASE_COMPLETE:
LOGP(0, LOGL_DEBUG, "USS Release Complete\n");
/* could also parse out the optional Cause/Facility data */
req->text[0] = 0xFF;
break;
case GSM0480_MTYPE_REGISTER:
case GSM0480_MTYPE_FACILITY:
rc &= parse_ussd_info_elements(&hdr->data[0], len - sizeof(*hdr), req);
break;
default:
LOGP(0, LOGL_DEBUG, "Unknown GSM 04.80 message-type field 0x%02x\n",
hdr->msg_type);
rc = 0;
break;
}
return rc;
}
static int parse_ussd_info_elements(const uint8_t *ussd_ie, uint16_t len,
struct ussd_request *req)
{
int rc = -1;
/* Information Element Identifier - table 3.2 & GSM 04.08 section 10.5 */
uint8_t iei;
uint8_t iei_length;
iei = ussd_ie[0];
iei_length = ussd_ie[1];
/* If the data does not fit, report an error */
if (len - 2 < iei_length)
return 0;
switch (iei) {
case GSM48_IE_CAUSE:
break;
case GSM0480_IE_FACILITY:
rc = parse_facility_ie(ussd_ie+2, iei_length, req);
break;
case GSM0480_IE_SS_VERSION:
break;
default:
LOGP(0, LOGL_DEBUG, "Unhandled GSM 04.08 or 04.80 IEI 0x%02x\n",
iei);
rc = 0;
break;
}
return rc;
}
static int parse_facility_ie(const uint8_t *facility_ie, uint16_t length,
struct ussd_request *req)
{
int rc = 1;
uint8_t offset = 0;
while (offset + 2 <= length) {
/* Component Type tag - table 3.7 */
uint8_t component_type = facility_ie[offset];
uint8_t component_length = facility_ie[offset+1];
/* size check */
if (offset + 2 + component_length > length) {
LOGP(0, LOGL_ERROR, "Component does not fit.\n");
return 0;
}
switch (component_type) {
case GSM0480_CTYPE_INVOKE:
rc &= parse_ss_invoke(facility_ie+2,
component_length,
req);
break;
case GSM0480_CTYPE_RETURN_RESULT:
break;
case GSM0480_CTYPE_RETURN_ERROR:
break;
case GSM0480_CTYPE_REJECT:
break;
default:
LOGP(0, LOGL_DEBUG, "Unknown GSM 04.80 Facility "
"Component Type 0x%02x\n", component_type);
rc = 0;
break;
}
offset += (component_length+2);
};
return rc;
}
/* Parse an Invoke component - see table 3.3 */
static int parse_ss_invoke(const uint8_t *invoke_data, uint16_t length,
struct ussd_request *req)
{
int rc = 1;
uint8_t offset;
if (length < 3)
return 0;
/* mandatory part */
if (invoke_data[0] != GSM0480_COMPIDTAG_INVOKE_ID) {
LOGP(0, LOGL_DEBUG, "Unexpected GSM 04.80 Component-ID tag "
"0x%02x (expecting Invoke ID tag)\n", invoke_data[0]);
}
offset = invoke_data[1] + 2;
req->invoke_id = invoke_data[2];
/* look ahead once */
if (offset + 1 > length)
return 0;
/* optional part */
if (invoke_data[offset] == GSM0480_COMPIDTAG_LINKED_ID)
offset += invoke_data[offset+1] + 2; /* skip over it */
/* mandatory part */
if (invoke_data[offset] == GSM0480_OPERATION_CODE) {
if (offset + 2 > length)
return 0;
uint8_t operation_code = invoke_data[offset+2];
switch (operation_code) {
case GSM0480_OP_CODE_PROCESS_USS_REQ:
rc = parse_process_uss_req(invoke_data + offset + 3,
length - offset - 3,
req);
break;
default:
LOGP(0, LOGL_DEBUG, "GSM 04.80 operation code 0x%02x "
"is not yet handled\n", operation_code);
rc = 0;
break;
}
} else {
LOGP(0, LOGL_DEBUG, "Unexpected GSM 04.80 Component-ID tag 0x%02x "
"(expecting Operation Code tag)\n",
invoke_data[0]);
rc = 0;
}
return rc;
}
/* Parse the parameters of a Process UnstructuredSS Request */
static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length,
struct ussd_request *req)
{
int rc = 0;
int num_chars;
uint8_t dcs;
/* we need at least that much */
if (length < 8)
return 0;
if (uss_req_data[0] == GSM_0480_SEQUENCE_TAG) {
if (uss_req_data[2] == ASN1_OCTET_STRING_TAG) {
dcs = uss_req_data[4];
if ((dcs == 0x0F) &&
(uss_req_data[5] == ASN1_OCTET_STRING_TAG)) {
num_chars = (uss_req_data[6] * 8) / 7;
/* Prevent a mobile-originated buffer-overrun! */
if (num_chars > MAX_LEN_USSD_STRING)
num_chars = MAX_LEN_USSD_STRING;
gsm_7bit_decode(req->text,
&(uss_req_data[7]), num_chars);
rc = 1;
}
}
}
return rc;
}
struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const char *text)
{
struct msgb *msg;
struct gsm48_hdr *gh;
uint8_t *ptr8;
int response_len;
msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
if (!msg)
return NULL;
/* First put the payload text into the message */
ptr8 = msgb_put(msg, 0);
response_len = gsm_7bit_encode(ptr8, text);
msgb_put(msg, response_len);
/* Then wrap it as an Octet String */
msgb_wrap_with_TL(msg, ASN1_OCTET_STRING_TAG);
/* Pre-pend the DCS octet string */
msgb_push_TLV1(msg, ASN1_OCTET_STRING_TAG, 0x0F);
/* Then wrap these as a Sequence */
msgb_wrap_with_TL(msg, GSM_0480_SEQUENCE_TAG);
/* Pre-pend the operation code */
msgb_push_TLV1(msg, GSM0480_OPERATION_CODE,
GSM0480_OP_CODE_PROCESS_USS_REQ);
/* Wrap the operation code and IA5 string as a sequence */
msgb_wrap_with_TL(msg, GSM_0480_SEQUENCE_TAG);
/* Pre-pend the invoke ID */
msgb_push_TLV1(msg, GSM0480_COMPIDTAG_INVOKE_ID, invoke_id);
/* Wrap this up as a Return Result component */
msgb_wrap_with_TL(msg, GSM0480_CTYPE_RETURN_RESULT);
/* Wrap the component in a Facility message */
msgb_wrap_with_TL(msg, GSM0480_IE_FACILITY);
/* And finally pre-pend the L3 header */
gh = (struct gsm48_hdr *) msgb_push(msg, sizeof(*gh));
gh->proto_discr = GSM48_PDISC_NC_SS | trans_id
| (1<<7); /* TI direction = 1 */
gh->msg_type = GSM0480_MTYPE_RELEASE_COMPLETE;
return msg;
}