GSUP/SMS: introduce MO-/MT-FORWARD-SM messages

According to 3GPP TS 29.002, there are two services:

  - MAP-MO-FORWARD-SHORT-MESSAGE (see 12.2),
  - MAP-MT-FORWARD-SHORT-MESSAGE (see 12.9),

which are used to forward MO/MT short messages.

This change replicates both services as GSUP messages:

  - OSMO_GSUP_MSGT_MO_FORWARD_SM_*,
  - OSMO_GSUP_MSGT_MT_FORWARD_SM_*.

Please note, that only the 'must-have' IEs are introduced
by this change, in particular the following:

  - OSMO_GSUP_SM_RP_MR_IE (see note below),
  - OSMO_GSUP_SM_RP_DA_IE (see 7.6.8.1),
  - OSMO_GSUP_SM_RP_OA_IE (see 7.6.8.2),
  - OSMO_GSUP_SM_RP_UI_IE (see 7.6.8.4),
  - OSMO_GSUP_SM_RP_MMS_IE (see 7.6.8.7),
  - OSMO_GSUP_SM_RP_CAUSE_IE (see GSM TS 04.11, 8.2.5.4),

where both SM_RP_DA and SM_RP_OA IEs basically contain
a single nested TV of the following format:

  - T: identity type (see 'osmo_gsup_sms_sm_rp_oda_t'),
  - V: encoded identity itself (optional).

According to GSM TS 04.11, every single message on the SM-RL has
an unique message reference (see 8.2.3), that is used to link
an RP-ACK or RP-ERROR message to the associated (preceding)
RP-DATA or RP-SMMA message transfer attempt.

In case of TCAP/MAP, this message reference is being mapped to the
Invoke ID. But since GSUP has no 'Invoke ID' IE, and it is not
required for other applications (other than SMS), this change
introduces a special 'SM_RP_MR' IE that doesn't exist in MAP.

Change-Id: Ibe325c64ae2d6c626b232533bb4cbc65fc2b5d71
Related Change-Id: (docs) Ie0150756c33c1352bc4eb49421824542c711175c
Related Change-Id: (TTCN) Ibf49474a81235096c032ea21f217170f523bd94e
Related: OS#3587

4 files changed, 336 insertions, 2 deletions

diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am
index ccb38add..3d2c5606 100644
--- a/src/gsm/Makefile.am
+++ b/src/gsm/Makefile.am
@@ -29,7 +29,7 @@ libgsmint_la_SOURCES =  a5.c rxlev_stat.c tlv_parser.c comp128.c comp128v23.c \
 			auth_milenage.c milenage/aes-encblock.c gea.c \
 			milenage/aes-internal.c milenage/aes-internal-enc.c \
 			milenage/milenage.c gan.c ipa.c gsm0341.c apn.c \
-			gsup.c gprs_gea.c gsm0503_conv.c oap.c gsm0808_utils.c \
+			gsup.c gsup_sms.c gprs_gea.c gsm0503_conv.c oap.c gsm0808_utils.c \
 			gsm23003.c mncc.c bts_features.c oap_client.c \
 			gsm29118.c
 libgsmint_la_LDFLAGS = -no-undefined
diff --git a/src/gsm/gsup.c b/src/gsm/gsup.c
index 18b35806..e4339971 100644
--- a/src/gsm/gsup.c
+++ b/src/gsm/gsup.c
@@ -67,6 +67,14 @@ const struct value_string osmo_gsup_message_type_names[] = {
 	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_PROC_SS_ERROR),
 	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_PROC_SS_RESULT),
 
+	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_MO_FORWARD_SM_REQUEST),
+	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_MO_FORWARD_SM_ERROR),
+	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_MO_FORWARD_SM_RESULT),
+
+	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_MT_FORWARD_SM_REQUEST),
+	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_MT_FORWARD_SM_ERROR),
+	OSMO_VALUE_STRING(OSMO_GSUP_MSGT_MT_FORWARD_SM_RESULT),
+
 	{ 0, NULL }
 };
 
@@ -434,6 +442,35 @@ int osmo_gsup_decode(const uint8_t *const_data, size_t data_len,
 			gsup_msg->ss_info_len = value_len;
 			break;
 
+		case OSMO_GSUP_SM_RP_MR_IE:
+			gsup_msg->sm_rp_mr = value;
+			break;
+
+		case OSMO_GSUP_SM_RP_DA_IE:
+			rc = osmo_gsup_sms_decode_sm_rp_da(gsup_msg, value, value_len);
+			if (rc)
+				return rc;
+			break;
+
+		case OSMO_GSUP_SM_RP_OA_IE:
+			rc = osmo_gsup_sms_decode_sm_rp_oa(gsup_msg, value, value_len);
+			if (rc)
+				return rc;
+			break;
+
+		case OSMO_GSUP_SM_RP_UI_IE:
+			gsup_msg->sm_rp_ui = value;
+			gsup_msg->sm_rp_ui_len = value_len;
+			break;
+
+		case OSMO_GSUP_SM_RP_MMS_IE:
+			gsup_msg->sm_rp_mms = value;
+			break;
+
+		case OSMO_GSUP_SM_RP_CAUSE_IE:
+			gsup_msg->sm_rp_cause = value;
+			break;
+
 		default:
 			LOGP(DLGSUP, LOGL_NOTICE,
 			     "GSUP IE type %d unknown\n", iei);
@@ -529,7 +566,7 @@ static void encode_auth_info(struct msgb *msg, enum osmo_gsup_iei iei,
 int osmo_gsup_encode(struct msgb *msg, const struct osmo_gsup_message *gsup_msg)
 {
 	uint8_t u8;
-	int idx;
+	int idx, rc;
 	uint8_t bcd_buf[GSM48_MI_SIZE] = {0};
 	size_t bcd_len;
 
@@ -626,6 +663,42 @@ int osmo_gsup_encode(struct msgb *msg, const struct osmo_gsup_message *gsup_msg)
 				gsup_msg->ss_info_len, gsup_msg->ss_info);
 	}
 
+	if (gsup_msg->sm_rp_mr) {
+		msgb_tlv_put(msg, OSMO_GSUP_SM_RP_MR_IE,
+				sizeof(*gsup_msg->sm_rp_mr), gsup_msg->sm_rp_mr);
+	}
+
+	if (gsup_msg->sm_rp_da_type) {
+		rc = osmo_gsup_sms_encode_sm_rp_da(msg, gsup_msg);
+		if (rc) {
+			LOGP(DLGSUP, LOGL_ERROR, "Failed to encode SM-RP-DA IE\n");
+			return -EINVAL;
+		}
+	}
+
+	if (gsup_msg->sm_rp_oa_type) {
+		rc = osmo_gsup_sms_encode_sm_rp_oa(msg, gsup_msg);
+		if (rc) {
+			LOGP(DLGSUP, LOGL_ERROR, "Failed to encode SM-RP-OA IE\n");
+			return -EINVAL;
+		}
+	}
+
+	if (gsup_msg->sm_rp_ui) {
+		msgb_tlv_put(msg, OSMO_GSUP_SM_RP_UI_IE,
+				gsup_msg->sm_rp_ui_len, gsup_msg->sm_rp_ui);
+	}
+
+	if (gsup_msg->sm_rp_mms) {
+		msgb_tlv_put(msg, OSMO_GSUP_SM_RP_MMS_IE,
+				sizeof(*gsup_msg->sm_rp_mms), gsup_msg->sm_rp_mms);
+	}
+
+	if (gsup_msg->sm_rp_cause) {
+		msgb_tlv_put(msg, OSMO_GSUP_SM_RP_CAUSE_IE,
+				sizeof(*gsup_msg->sm_rp_cause), gsup_msg->sm_rp_cause);
+	}
+
 	return 0;
 }
 
diff --git a/src/gsm/gsup_sms.c b/src/gsm/gsup_sms.c
new file mode 100644
index 00000000..d49cf20a
--- /dev/null
+++ b/src/gsm/gsup_sms.c
@@ -0,0 +1,256 @@
+/*
+ * (C) 2018 by Vadim Yanitskiy <axilirator@gmail.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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+#include <osmocom/core/logging.h>
+#include <osmocom/core/msgb.h>
+
+#include <osmocom/gsm/gsup.h>
+#include <osmocom/gsm/tlv.h>
+
+/*! \addtogroup gsup
+ *  @{
+ *  \file gsup_sms.c
+ *  SMS (Short Message Service) extensions for Osmocom GSUP.
+ */
+
+/*! Encode SM-RP-DA IE (see 7.6.8.1), Destination Address.
+ * \param[out] msg      target message buffer (caller-allocated)
+ * \param[in]  gsup_msg abstract GSUP message structure
+ * \returns 0 in case of success, negative in case of error
+ */
+int osmo_gsup_sms_encode_sm_rp_da(struct msgb *msg,
+	const struct osmo_gsup_message *gsup_msg)
+{
+	uint8_t *id_enc;
+
+	switch (gsup_msg->sm_rp_da_type) {
+	case OSMO_GSUP_SMS_SM_RP_ODA_IMSI:
+	case OSMO_GSUP_SMS_SM_RP_ODA_MSISDN:
+	case OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR:
+		/* Prevent NULL-pointer (or empty) dereference */
+		if (gsup_msg->sm_rp_da == NULL || gsup_msg->sm_rp_da_len == 0) {
+			LOGP(DLGSUP, LOGL_ERROR, "Empty?!? SM-RP-DA ID "
+				"(type=0x%02x)!\n", gsup_msg->sm_rp_da_type);
+			return -EINVAL;
+		}
+		break;
+
+	/* Special case for noSM-RP-DA */
+	case OSMO_GSUP_SMS_SM_RP_ODA_NULL:
+		break;
+
+	case OSMO_GSUP_SMS_SM_RP_ODA_NONE:
+	default:
+		LOGP(DLGSUP, LOGL_ERROR, "Unexpected SM-RP-DA ID "
+			"(type=0x%02x)!\n", gsup_msg->sm_rp_da_type);
+		return -EINVAL;
+	}
+
+	/* SM-RP-DA tag | len | ... */
+	msgb_tv_put(msg, OSMO_GSUP_SM_RP_DA_IE, gsup_msg->sm_rp_da_len + 1);
+	msgb_v_put(msg, gsup_msg->sm_rp_da_type); /* ... | id_type */
+
+	if (gsup_msg->sm_rp_da_type == OSMO_GSUP_SMS_SM_RP_ODA_NULL)
+		return 0;
+
+	/* ... | id_enc */
+	id_enc = msgb_put(msg, gsup_msg->sm_rp_da_len);
+	memcpy(id_enc, gsup_msg->sm_rp_da, gsup_msg->sm_rp_da_len);
+
+	return 0;
+}
+
+/*! Decode SM-RP-DA IE (see 7.6.8.1), Destination Address.
+ * \param[out] gsup_msg abstract GSUP message structure
+ * \param[in]  data     pointer to the raw IE payload
+ * \param[in]  data_len length of IE pointed by \ref data
+ * \returns 0 in case of success, negative in case of error
+ */
+int osmo_gsup_sms_decode_sm_rp_da(struct osmo_gsup_message *gsup_msg,
+	uint8_t *data, size_t data_len)
+{
+	uint8_t *ptr = data;
+	uint8_t id_type;
+
+	/* There should be at least id_type */
+	if (data_len < 1) {
+		LOGP(DLGSUP, LOGL_ERROR, "Corrupted SM-RP-DA IE "
+			"(missing identity type)\n");
+		return -EINVAL;
+	}
+
+	/* ... | id_type | id_enc (optional) */
+	id_type = *ptr++;
+	data_len--;
+
+	/* Parse ID type */
+	switch (id_type) {
+	case OSMO_GSUP_SMS_SM_RP_ODA_IMSI:
+	case OSMO_GSUP_SMS_SM_RP_ODA_MSISDN:
+	case OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR:
+		if (!data_len) {
+			/* ID shall not be empty (if its type != NULL) */
+			LOGP(DLGSUP, LOGL_ERROR, "Corrupted SM-RP-DA IE "
+				"(missing encoded identity)\n");
+			return -EINVAL;
+		}
+
+		gsup_msg->sm_rp_da_type = id_type;
+		gsup_msg->sm_rp_da_len = data_len;
+		gsup_msg->sm_rp_da = ptr;
+		break;
+
+	/* Special case for noSM-RP-DA */
+	case OSMO_GSUP_SMS_SM_RP_ODA_NULL:
+		if (data_len != 0) {
+			LOGP(DLGSUP, LOGL_ERROR, "Unexpected SM-RP-DA ID, "
+				"(id_len != 0) for noSM-RP-DA!\n");
+			return -EINVAL;
+		}
+
+		gsup_msg->sm_rp_da_type = id_type;
+		gsup_msg->sm_rp_da_len = 0;
+		gsup_msg->sm_rp_da = NULL;
+		break;
+
+	case OSMO_GSUP_SMS_SM_RP_ODA_NONE:
+	default:
+		LOGP(DLGSUP, LOGL_ERROR, "Unexpected SM-RP-DA ID "
+			"(type=0x%02x)!\n", id_type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*! Encode SM-RP-OA IE (see 7.6.8.2), Originating Address.
+ * \param[out] msg      target message buffer (caller-allocated)
+ * \param[in]  gsup_msg abstract GSUP message structure
+ * \returns 0 in case of success, negative in case of error
+ */
+int osmo_gsup_sms_encode_sm_rp_oa(struct msgb *msg,
+	const struct osmo_gsup_message *gsup_msg)
+{
+	uint8_t *id_enc;
+
+	switch (gsup_msg->sm_rp_oa_type) {
+	case OSMO_GSUP_SMS_SM_RP_ODA_MSISDN:
+	case OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR:
+		/* Prevent NULL-pointer (or empty) dereference */
+		if (gsup_msg->sm_rp_oa == NULL || gsup_msg->sm_rp_oa_len == 0) {
+			LOGP(DLGSUP, LOGL_ERROR, "Empty?!? SM-RP-OA ID "
+				"(type=0x%02x)!\n", gsup_msg->sm_rp_oa_type);
+			return -EINVAL;
+		}
+		break;
+
+	/* Special case for noSM-RP-OA */
+	case OSMO_GSUP_SMS_SM_RP_ODA_NULL:
+		break;
+
+	case OSMO_GSUP_SMS_SM_RP_ODA_NONE:
+	default:
+		LOGP(DLGSUP, LOGL_ERROR, "Unexpected SM-RP-OA ID "
+			"(type=0x%02x)!\n", gsup_msg->sm_rp_oa_type);
+		return -EINVAL;
+	}
+
+	/* SM-RP-OA tag | len | ... */
+	msgb_tv_put(msg, OSMO_GSUP_SM_RP_OA_IE, gsup_msg->sm_rp_oa_len + 1);
+	msgb_v_put(msg, gsup_msg->sm_rp_oa_type); /* ... | id_type */
+
+	if (gsup_msg->sm_rp_oa_type == OSMO_GSUP_SMS_SM_RP_ODA_NULL)
+		return 0;
+
+	/* ... | id_enc */
+	id_enc = msgb_put(msg, gsup_msg->sm_rp_oa_len);
+	memcpy(id_enc, gsup_msg->sm_rp_oa, gsup_msg->sm_rp_oa_len);
+
+	return 0;
+}
+
+/*! Decode SM-RP-OA IE (see 7.6.8.2), Originating Address.
+ * \param[out] gsup_msg abstract GSUP message structure
+ * \param[in]  data     pointer to the raw IE payload
+ * \param[in]  data_len length of IE pointed by \ref data
+ * \returns 0 in case of success, negative in case of error
+ */
+int osmo_gsup_sms_decode_sm_rp_oa(struct osmo_gsup_message *gsup_msg,
+	uint8_t *data, size_t data_len)
+{
+	uint8_t *ptr = data;
+	uint8_t id_type;
+
+	/* There should be at least id_type */
+	if (data_len < 1) {
+		LOGP(DLGSUP, LOGL_ERROR, "Corrupted SM-RP-OA IE "
+			"(missing identity type)\n");
+		return -EINVAL;
+	}
+
+	/* ... | id_type | id_enc (optional) */
+	id_type = *ptr++;
+	data_len--;
+
+	/* Parse ID type */
+	switch (id_type) {
+	case OSMO_GSUP_SMS_SM_RP_ODA_IMSI:
+	case OSMO_GSUP_SMS_SM_RP_ODA_MSISDN:
+	case OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR:
+		if (!data_len) {
+			/* ID shall not be empty (if its type != NULL) */
+			LOGP(DLGSUP, LOGL_ERROR, "Corrupted SM-RP-OA IE "
+				"(missing encoded identity)\n");
+			return -EINVAL;
+		}
+
+		gsup_msg->sm_rp_oa_type = id_type;
+		gsup_msg->sm_rp_oa_len = data_len;
+		gsup_msg->sm_rp_oa = ptr;
+		break;
+
+	/* Special case for noSM-RP-DA */
+	case OSMO_GSUP_SMS_SM_RP_ODA_NULL:
+		if (data_len != 0) {
+			LOGP(DLGSUP, LOGL_ERROR, "Unexpected SM-RP-OA ID, "
+				"(id_len != 0) for noSM-RP-DA!\n");
+			return -EINVAL;
+		}
+
+		gsup_msg->sm_rp_oa_type = id_type;
+		gsup_msg->sm_rp_oa_len = 0;
+		gsup_msg->sm_rp_oa = NULL;
+		break;
+
+	case OSMO_GSUP_SMS_SM_RP_ODA_NONE:
+	default:
+		LOGP(DLGSUP, LOGL_ERROR, "Unexpected SM-RP-OA ID "
+			"(type=0x%02x)!\n", id_type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*! @} */
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 959d1827..90c21954 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -523,6 +523,11 @@ osmo_gsup_message_type_names;
 osmo_gsup_session_state_names;
 osmo_gsup_get_err_msg_type;
 
+osmo_gsup_sms_encode_sm_rp_da;
+osmo_gsup_sms_decode_sm_rp_da;
+osmo_gsup_sms_encode_sm_rp_oa;
+osmo_gsup_sms_decode_sm_rp_oa;
+
 osmo_oap_encode;
 osmo_oap_decode;