gsm: Add APN conversion functions

These functions are currently part of openbsc but also needed by
other projects.

The function have been renamed as follows:

  gprs_apn_to_str -> osmo_apn_to_str
  gprs_str_to_apn -> osmo_apn_from_str

Sponsored-by: On-Waves ehf

2 files changed, 123 insertions, 0 deletions

diff --git a/tests/gprs/gprs_test.c b/tests/gprs/gprs_test.c
new file mode 100644
index 00000000..be80e5c0
--- /dev/null
+++ b/tests/gprs/gprs_test.c
@@ -0,0 +1,122 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include <osmocom/core/application.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/gsm/apn.h>
+
+static void apn_round_trip(const uint8_t *input, size_t len, const char *wanted_output)
+{
+	char output[len ? len : 1];
+	uint8_t encoded[len + 50];
+	char *out_str;
+	int enc_len;
+
+	/* decode and verify we have what we want */
+	out_str = osmo_apn_to_str(output, input, len);
+	OSMO_ASSERT(out_str);
+	OSMO_ASSERT(out_str == &output[0]);
+	OSMO_ASSERT(strlen(out_str) == strlen(wanted_output));
+	OSMO_ASSERT(strcmp(out_str, wanted_output) == 0);
+
+	/* encode and verify it */
+	if (len != 0) {
+		enc_len = osmo_apn_from_str(encoded, ARRAY_SIZE(encoded), wanted_output);
+		OSMO_ASSERT(enc_len == len);
+		OSMO_ASSERT(memcmp(encoded, input, enc_len) == 0);
+	} else {
+		enc_len = osmo_apn_from_str(encoded, 0, wanted_output);
+		OSMO_ASSERT(enc_len == -1);
+	}
+}
+
+static void test_gsm_03_03_apn(void)
+{
+
+	{
+		/* test invalid writes */
+		const uint8_t ref[10] = { 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF };
+		uint8_t output[10];
+		int enc_len;
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 0, "");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref, output, ARRAY_SIZE(ref)) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 0, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref, output, ARRAY_SIZE(ref)) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 1, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref + 1, output + 1, ARRAY_SIZE(ref) - 1) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 2, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref + 2, output + 2, ARRAY_SIZE(ref) - 2) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 3, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref + 3, output + 3, ARRAY_SIZE(ref) - 3) == 0);
+	}
+
+	{
+		/* single empty label */
+		uint8_t input[] = { 0x0 };
+		const char *output = "";
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+	}
+
+	{
+		/* no label */
+		uint8_t input[] = { };
+		const char *output = "";
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+	}
+
+	{
+		/* single label with A */
+		uint8_t input[] = { 0x1, 65 };
+		const char *output = "A";
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+		OSMO_ASSERT(osmo_apn_to_str(NULL, input, ARRAY_SIZE(input) - 1) == NULL);
+	}
+
+	{
+		uint8_t input[] = { 0x3, 65, 66, 67, 0x2, 90, 122 };
+		const char *output = "ABC.Zz";
+		char tmp[strlen(output) + 1];
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 1) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 2) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 4) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 5) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 6) == NULL);
+	}
+}
+
+const struct log_info_cat default_categories[] = {
+};
+
+static struct log_info info = {
+	.cat = default_categories,
+	.num_cat = ARRAY_SIZE(default_categories),
+};
+
+int main(int argc, char **argv)
+{
+	osmo_init_logging(&info);
+
+	test_gsm_03_03_apn();
+
+	printf("Done.\n");
+	return EXIT_SUCCESS;
+}
diff --git a/tests/gprs/gprs_test.ok b/tests/gprs/gprs_test.ok
new file mode 100644
index 00000000..619c5618
--- /dev/null
+++ b/tests/gprs/gprs_test.ok
@@ -0,0 +1 @@
+Done.