This patch moves the GSM-specific functions to the new library

libosmogsm which is provided by libosmocore.

I have also moved generate_backtrace() to backtrace.c instead
of gsm_utils.c, otherwise the timer and msgfile tests depend on
libosmogsm.

Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>

1 files changed, 461 insertions, 0 deletions

diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
new file mode 100644
index 00000000..b6b345cb
--- /dev/null
+++ b/src/gsm/gsm0480.c
@@ -0,0 +1,461 @@
+/* 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;
+}