WIP: implement routing of SMS over GSUPfixeria/sms

Change-Id: Ibaa64edca06bd32d651e9c16ca0c8a56a6bc67b2

3 files changed, 352 insertions, 0 deletions

diff --git a/include/osmocom/hlr/hlr_sms.h b/include/osmocom/hlr/hlr_sms.h
index 8e06b9e..dc72d32 100644
--- a/include/osmocom/hlr/hlr_sms.h
+++ b/include/osmocom/hlr/hlr_sms.h
@@ -26,3 +26,13 @@ struct hlr_sms_route *sms_route_alloc(struct hlr *hlr,
 				      const char *pattern,
 				      const struct hlr_euse *euse);
 void sms_route_del(struct hlr_sms_route *rt);
+
+int forward_mo_sms(struct osmo_gsup_conn *conn,
+		   const struct osmo_gsup_message *gsup,
+		   struct msgb *msg);
+int forward_sm_res_or_err(struct osmo_gsup_conn *conn,
+			  const struct osmo_gsup_message *gsup,
+			  struct msgb *msg);
+int forward_mt_sms(struct osmo_gsup_conn *conn,
+		   const struct osmo_gsup_message *gsup,
+		   struct msgb *msg);
diff --git a/src/hlr.c b/src/hlr.c
index 770590c..22ad406 100644
--- a/src/hlr.c
+++ b/src/hlr.c
@@ -47,6 +47,7 @@
 #include <osmocom/hlr/luop.h>
 #include <osmocom/hlr/hlr_vty.h>
 #include <osmocom/hlr/hlr_ussd.h>
+#include <osmocom/hlr/hlr_sms.h>
 
 struct hlr *g_hlr;
 static void *hlr_ctx = NULL;
@@ -663,6 +664,28 @@ static int read_cb(struct osmo_gsup_conn *conn, struct msgb *msg)
 	case OSMO_GSUP_MSGT_PROC_SS_ERROR:
 		rx_proc_ss_error(conn, &gsup);
 		break;
+
+	/* Short Message from MSC/VLR towards SMSC */
+	case OSMO_GSUP_MSGT_MO_FORWARD_SM_REQUEST:
+	case OSMO_GSUP_MSGT_READY_FOR_SM_REQUEST:
+		forward_mo_sms(conn, &gsup, msg);
+		return 0; /* Do not free msgb */
+
+	/* Short Message from SMSC towards MSC/VLR */
+	case OSMO_GSUP_MSGT_MT_FORWARD_SM_REQUEST:
+		forward_mt_sms(conn, &gsup, msg);
+		return 0; /* Do not free msgb */
+
+	/* Short Message delivery status, to be forwarded 'as-is' */
+	case OSMO_GSUP_MSGT_MO_FORWARD_SM_RESULT:
+	case OSMO_GSUP_MSGT_MT_FORWARD_SM_RESULT:
+	case OSMO_GSUP_MSGT_MO_FORWARD_SM_ERROR:
+	case OSMO_GSUP_MSGT_MT_FORWARD_SM_ERROR:
+	case OSMO_GSUP_MSGT_READY_FOR_SM_RESULT:
+	case OSMO_GSUP_MSGT_READY_FOR_SM_ERROR:
+		forward_sm_res_or_err(conn, &gsup, msg);
+		return 0; /* Do not free msgb */
+
 	case OSMO_GSUP_MSGT_INSERT_DATA_ERROR:
 	case OSMO_GSUP_MSGT_INSERT_DATA_RESULT:
 	case OSMO_GSUP_MSGT_LOCATION_CANCEL_ERROR:
diff --git a/src/hlr_sms.c b/src/hlr_sms.c
index 7e2c145..8ee01f2 100644
--- a/src/hlr_sms.c
+++ b/src/hlr_sms.c
@@ -24,6 +24,10 @@
 #include <errno.h>
 
 #include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
+
+#include <osmocom/gsm/protocol/gsm_04_11.h>
+#include <osmocom/gsm/gsm48_ie.h>
 #include <osmocom/gsm/gsup.h>
 
 #include <osmocom/hlr/hlr.h>
@@ -77,3 +81,318 @@ void sms_route_del(struct hlr_sms_route *rt)
 	llist_del(&rt->list);
 	talloc_free(rt);
 }
+
+/* Common helper for preparing to be encoded GSUP message */
+static void gsup_prepare_sm_error(struct osmo_gsup_message *msg,
+				  const struct osmo_gsup_message *src_msg)
+{
+	/* Init a mew GSUP message */
+	*msg = (struct osmo_gsup_message) {
+		.message_type = OSMO_GSUP_TO_MSGT_ERROR(src_msg->message_type),
+		.message_class = OSMO_GSUP_MESSAGE_CLASS_SMS,
+		.sm_rp_mr = src_msg->sm_rp_mr,
+
+		/* Swap optional source and destination addresses */
+		.destination_name_len = src_msg->source_name_len,
+		.destination_name = src_msg->source_name,
+	};
+
+	/* Fill in subscriber's IMSI */
+	OSMO_STRLCPY_ARRAY(msg->imsi, src_msg->imsi);
+}
+
+static int gsup_conn_enc_send(struct osmo_gsup_conn *conn,
+			      struct osmo_gsup_message *msg)
+{
+	struct msgb *gsup_msgb;
+	int rc;
+
+	gsup_msgb = msgb_alloc_headroom(512, 64, __func__);
+	if (!gsup_msgb) {
+		LOGP(DLSMS, LOGL_ERROR, "Failed to allocate a GSUP message\n");
+		return -ENOMEM;
+	}
+
+	rc = osmo_gsup_encode(gsup_msgb, msg);
+	if (rc) {
+		LOGP(DLSMS, LOGL_ERROR, "Failed to encode GSUP message '%s' (rc=%d)\n",
+		     osmo_gsup_message_type_name(msg->message_type), rc);
+		return rc;
+	}
+
+	rc = osmo_gsup_conn_send(conn, gsup_msgb);
+	if (rc) {
+		LOGP(DLSMS, LOGL_ERROR, "Failed to send GSUP message '%s' (rc=%d)\n",
+		     osmo_gsup_message_type_name(msg->message_type), rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+/* Short Message delivery status, to be forwarded 'as-is' */
+int forward_sm_res_or_err(struct osmo_gsup_conn *conn,
+			  const struct osmo_gsup_message *gsup,
+			  struct msgb *msg)
+{
+	struct hlr_subscriber subscr;
+	char src_name_buf[32];
+	char dst_name_buf[32];
+	int rc;
+
+	rc = db_subscr_get_by_imsi(g_hlr->dbc, gsup->imsi, &subscr);
+	if (rc) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' for unknown subscriber IMSI-%s\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		/* TODO: send some error back? */
+		msgb_free(msg);
+		return -ENODEV;
+	}
+
+	/* Make sure destination name is present */
+	if (gsup->destination_name == NULL || !gsup->destination_name_len) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' (IMSI-%s) without destination name\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		/* TODO: send some error back? */
+		msgb_free(msg);
+		return -EINVAL;
+	}
+
+	/* Make sure source name is present */
+	if (gsup->source_name == NULL || !gsup->source_name_len) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' (IMSI-%s) without source name\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		/* TODO: send some error back? */
+		msgb_free(msg);
+		return -EINVAL;
+	}
+
+	LOGP(DLSMS, LOGL_INFO, "Forward '%s' (IMSI-%s) from %s to %s\n",
+	     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi,
+	     osmo_quote_str_buf2(src_name_buf, sizeof(src_name_buf),
+				 (const char *) gsup->source_name,
+				 gsup->source_name_len),
+	     osmo_quote_str_buf2(dst_name_buf, sizeof(dst_name_buf),
+				 (const char *) gsup->destination_name,
+				 gsup->destination_name_len));
+
+	rc = osmo_gsup_addr_send(conn->server, gsup->destination_name,
+				 gsup->destination_name_len, msg);
+	if (rc) {
+		LOGP(DLSMS, LOGL_NOTICE, "Failed to forward '%s' (IMSI-%s)\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		/* osmo_gsup_addr_send() free()d msg */
+		return rc;
+	}
+
+	return 0;
+}
+
+static const struct hlr_euse *find_euse(const struct hlr_subscriber *subscr,
+					const char *smsc_addr)
+{
+	struct hlr_sms_route *rt;
+	const char *pattern;
+
+	/* Iterate over all known routes */
+	llist_for_each_entry(rt, &g_hlr->sms_routes, list) {
+		switch (rt->type) {
+		case HLR_SMS_RT_SMSC_ADDR:
+			pattern = smsc_addr;
+			break;
+		case HLR_SMS_RT_SENDER_MSISDN:
+			pattern = subscr->msisdn;
+			break;
+		case HLR_SMS_RT_SENDER_IMSI:
+			pattern = subscr->imsi;
+			break;
+		default:
+			/* Shall not happen, make Coverity happy */
+			continue;
+		}
+
+		if (strcmp(rt->match_pattern, pattern) == 0)
+			return rt->euse;
+	}
+
+	/* Fall-back to default route if nothing will be found */
+	return g_hlr->sms_euse_default;
+}
+
+static const struct osmo_gsup_conn *find_conn(struct osmo_gsup_server *srv,
+					      const struct hlr_euse *euse)
+{
+	char euse_addr[128];
+	int rc;
+
+	rc = snprintf(euse_addr, sizeof(euse_addr), "EUSE-%s", euse->name);
+	return gsup_route_find(srv, (uint8_t *) euse_addr, rc + 1);
+}
+
+/* Short Message from MSC/VLR towards SMSC */
+int forward_mo_sms(struct osmo_gsup_conn *conn,
+		   const struct osmo_gsup_message *gsup,
+		   struct msgb *msg)
+{
+	char smsc_addr[GSM23003_MSISDN_MAX_DIGITS + 1];
+	struct osmo_gsup_message rsp_msg;
+	struct hlr_subscriber subscr;
+	uint8_t ext, ton, npi;
+	uint8_t sm_rp_cause;
+	int rc;
+
+	rc = db_subscr_get_by_imsi(g_hlr->dbc, gsup->imsi, &subscr);
+	if (rc) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' for unknown subscriber IMSI-%s\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		rsp_msg.cause = GMM_CAUSE_IMSI_UNKNOWN;
+		goto exit_error;
+	}
+
+	/* Make sure SM-RP-DA (SMSC address) is present */
+	if (gsup->sm_rp_da == NULL || !gsup->sm_rp_da_len) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' (IMSI-%s) without mandatory SM-RP-DA\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		rsp_msg.cause = GMM_CAUSE_INV_MAND_INFO;
+		goto exit_error;
+	}
+
+	if (gsup->sm_rp_da_type != OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' (IMSI-%s) with unexpected SM-RP-DA 0x%02x\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi,
+		     gsup->sm_rp_da_type);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		rsp_msg.cause = GMM_CAUSE_INV_MAND_INFO;
+		goto exit_error;
+	}
+
+	/* Parse ToN (Type of Number) / NPI (Numbering Plan Indicator) */
+	ext = (gsup->sm_rp_da[0] >> 7) ^ 0x01; /* NOTE: inversed */
+	ton = (gsup->sm_rp_da[0] >> 4) & 0x07;
+	npi = gsup->sm_rp_da[0] & 0x0f;
+
+	/* We only support International ISDN/telephone format */
+	if (ext || ton != 0x01 || npi != 0x01) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' (IMSI-%s) with unsupported SMSC address format: "
+					 "ToN=0x%02x, NPI=0x%02x\n, extension=%s\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi,
+		     ton, npi, ext ? "yes" : "no");
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		rsp_msg.cause = GMM_CAUSE_SEM_INCORR_MSG;
+		goto exit_error;
+	}
+
+	/* Decode SMSC address from SM-RP-DA */
+	rc = osmo_bcd2str(smsc_addr, sizeof(smsc_addr), gsup->sm_rp_da + 1,
+			  2, (gsup->sm_rp_da_len - 1) * 2, true);
+	if (rc < 0 || rc >= sizeof(smsc_addr)) {
+		LOGP(DLSMS, LOGL_NOTICE, "Failed to decode SMSC address from '%s' (IMSI-%s): rc=%d\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi, rc);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		rsp_msg.cause = GMM_CAUSE_SEM_INCORR_MSG;
+		goto exit_error;
+	}
+
+	/* Attempt to find a EUSE */
+	const struct hlr_euse *euse = find_euse(&subscr, smsc_addr);
+	if (euse == NULL) {
+		LOGP(DLSMS, LOGL_NOTICE, "Failed to find a route for '%s' (IMSI-%s, MR-0x%02x)\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi, *gsup->sm_rp_mr);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		sm_rp_cause = GSM411_RP_CAUSE_MO_NUM_UNASSIGNED;
+		rsp_msg.sm_rp_cause = &sm_rp_cause;
+		goto exit_error;
+	}
+
+	const struct osmo_gsup_conn *euse_conn = find_conn(conn->server, euse);
+	if (euse_conn == NULL) {
+		LOGP(DLSMS, LOGL_ERROR, "EUSE '%s' is not connected!\n", euse->name);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		sm_rp_cause = GSM411_RP_CAUSE_MO_TEMP_FAIL;
+		rsp_msg.sm_rp_cause = &sm_rp_cause;
+		goto exit_error;
+	}
+
+	LOGP(DLSMS, LOGL_INFO, "Forwarding '%s' (IMSI-%s, MR-0x%02x) to SMSC '%s'\n",
+	     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi,
+	     *gsup->sm_rp_mr, euse->name);
+
+	/* HACK: make sure source name is present, fill in if needed */
+	if (gsup->source_name == NULL || !gsup->source_name_len) {
+		/* FIXME: distinguish between MSC/VLR and SGSN */
+		msgb_tlv_put(msg, OSMO_GSUP_SOURCE_NAME_IE,
+			     strlen(subscr.vlr_number) + 1,
+			     (uint8_t *) subscr.vlr_number);
+	}
+
+	/* Ensure the buffer has enough headroom to put IPA headers */
+	msgb_pull_to_l2(msg);
+
+	/* Finally forward the original message */
+	rc = osmo_gsup_conn_send((struct osmo_gsup_conn *) euse_conn, msg);
+	if (rc) {
+		LOGP(DLSMS, LOGL_ERROR, "Failed to send GSUP message '%s' (rc=%d)\n",
+		     osmo_gsup_message_type_name(gsup->message_type), rc);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		sm_rp_cause = GSM411_RP_CAUSE_MO_TEMP_FAIL;
+		rsp_msg.sm_rp_cause = &sm_rp_cause;
+		msg = NULL; /* free()d by osmo_gsup_conn_send() */
+		goto exit_error;
+	}
+
+	return 0;
+
+exit_error:
+	gsup_conn_enc_send(conn, &rsp_msg);
+	if (msg != NULL)
+		talloc_free(msg);
+	return rc;
+}
+
+/* Short Message from SMSC towards MSC/VLR */
+int forward_mt_sms(struct osmo_gsup_conn *conn,
+		   const struct osmo_gsup_message *gsup,
+		   struct msgb *msg)
+{
+	struct osmo_gsup_message rsp_msg;
+	struct hlr_subscriber subscr;
+	uint8_t sm_rp_cause;
+	int rc;
+
+	rc = db_subscr_get_by_imsi(g_hlr->dbc, gsup->imsi, &subscr);
+	if (rc) {
+		LOGP(DLSMS, LOGL_NOTICE, "Rx '%s' for unknown subscriber IMSI-%s\n",
+		     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		rsp_msg.cause = GMM_CAUSE_IMSI_UNKNOWN;
+		goto exit_error;
+	}
+
+#if 0
+	LOGP(DLSMS, LOGL_INFO, "Forwarding '%s' (IMSI-%s, MR-0x%02x) to MSC/VLR '%s'\n",
+	     osmo_gsup_message_type_name(gsup->message_type), gsup->imsi,
+	     *gsup->sm_rp_mr, FIXME!);
+
+	/* Finally forward the original message */
+	rc = osmo_gsup_conn_send(subscr_conn, msg);
+	if (rc) {
+		LOGP(DLSMS, LOGL_ERROR, "Failed to send GSUP message '%s' (rc=%d)\n",
+		     osmo_gsup_message_type_name(gsup->message_type), rc);
+		gsup_prepare_sm_error(&rsp_msg, gsup);
+		sm_rp_cause = GSM411_RP_CAUSE_MO_TEMP_FAIL;
+		rsp_msg.sm_rp_cause = &sm_rp_cause;
+		msg = NULL; /* free()d by osmo_gsup_conn_send() */
+		goto exit_error;
+	}
+#endif
+
+	return 0;
+
+exit_error:
+	gsup_conn_enc_send(conn, &rsp_msg);
+	if (msg != NULL)
+		talloc_free(msg);
+	return rc;
+}