--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/smsc-daemon/main.c	Thu Aug 17 22:56:49 2023 -0800
@@ -0,0 +1,126 @@
+/*
+ * This C module is part of proto-smsc-daemon concoction, a prototype/test
+ * implementation of a GSUP-based GSM SMSC.  It is based on the osmo-demo-euse
+ * program from OsmoHLR package.
+ *
+ * proto-smsc-daemon author: Mychaela N. Falconia <falcon@freecalypso.org>,
+ * no copyright.
+ *
+ * osmo-demo-euse author: Harald Welte <laforge@gnumonks.org>, (C) 2018, AGPL3+
+ */
+
+#include <ctype.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <signal.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/application.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/gsm/gsup.h>
+
+#include <osmocom/gsupclient/gsup_client.h>
+
+#include "logging.h"
+
+extern int gsupc_read_cb(struct osmo_gsup_client *gsupc, struct msgb *msg);
+
+char smsc_addr_num[21];		/* maximum of 20 digits per GSM 04.11 */
+uint8_t smsc_addr_ton_npi;
+FILE *smsc_log_file;
+char smsc_gsup_name[26];
+struct osmo_gsup_client *g_gc;
+
+static struct log_info_cat default_categories[] = {
+	[DMAIN] = {
+		.name = "DMAIN",
+		.description = "Main Program",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
+};
+
+static const struct log_info smsc_log_info = {
+	.cat = default_categories,
+	.num_cat = ARRAY_SIZE(default_categories),
+};
+
+static void parse_smsc_addr_arg(char *arg)
+{
+	char *cp, *dp, *endp;
+	unsigned ndig;
+
+	cp = arg;
+	dp = smsc_addr_num;
+	ndig = 0;
+	while (isdigit(*cp)) {
+		if (ndig >= 20) {
+			fprintf(stderr,
+	"error: SMSC address argument exceeds GSM 04.11 limit of 20 digits\n");
+			exit(1);
+		}
+		*dp++ = *cp++;
+		ndig++;
+	}
+	if (!ndig) {
+invalid:	fprintf(stderr,
+			"error: SMSC address argument \"%s\" is invalid\n",
+			arg);
+		exit(1);
+	}
+	if (!*cp) {
+		/* default to TON=1, NPI=1, i.e., a pretend Global Title */
+		smsc_addr_ton_npi = 0x91;
+		return;
+	}
+	if (*cp++ != ',')
+		goto invalid;
+	if (!*cp)
+		goto invalid;
+	smsc_addr_ton_npi = strtoul(cp, &endp, 0);
+	if (*endp)
+		goto invalid;
+}
+
+static void open_log_file(char *filename)
+{
+	smsc_log_file = fopen(filename, "a");
+	if (!smsc_log_file) {
+		perror(filename);
+		exit(1);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	char *server_host = "127.0.0.1";
+	uint16_t server_port = OSMO_GSUP_PORT;
+	void *ctx = talloc_named_const(NULL, 0, "proto-smsc");
+
+	osmo_init_logging2(ctx, &smsc_log_info);
+
+	if (argc != 3) {
+		fprintf(stderr, "usage: %s smsc-addr logfile\n", argv[0]);
+		exit(1);
+	}
+	parse_smsc_addr_arg(argv[1]);
+	open_log_file(argv[2]);
+
+	sprintf(smsc_gsup_name, "SMSC-%s", smsc_addr_num);
+	g_gc = osmo_gsup_client_create(ctx, smsc_gsup_name, server_host,
+					server_port, gsupc_read_cb, NULL);
+	if (!g_gc) {
+		fprintf(stderr, "error: osmo_gsup_client_create() failed\n");
+		exit(1);
+	}
+
+	while (1) {
+		osmo_select_main(0);
+	}
+
+	exit(0);
+}