tests: Introduce a very basic gsm0808 test

This tests verifies the content of the GSM 08.08 messages, it does
not verify the remaining headroom (which the SCCP/IPA code relies
on being plenty to prepend the header). More to come in the future.
diff --git a/tests/gsm0808/gsm0808_test.c b/tests/gsm0808/gsm0808_test.c
new file mode 100644
index 0000000..50838c8
--- /dev/null
+++ b/tests/gsm0808/gsm0808_test.c
@@ -0,0 +1,261 @@
+/*
+ * (C) 2012 by Holger Hans Peter Freyther
+ * 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 <osmocom/gsm/gsm0808.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define VERIFY(msg, data, len) 						\
+	if (msgb_l3len(msg) != len) {					\
+		printf("%s:%d Length don't match: %d vs. %d. %s\n", 	\
+			__func__, __LINE__, msgb_l3len(msg), len,	\
+			osmo_hexdump(msg->l3h, msgb_l3len(msg))); 	\
+		abort();						\
+	} else if (memcmp(msg->l3h, data, len) != 0) {			\
+		printf("%s:%d didn't match: got: %s\n",			\
+			__func__, __LINE__,				\
+			osmo_hexdump(msg->l3h, msgb_l3len(msg)));	\
+		abort();						\
+	}
+
+
+static void test_create_layer3(void)
+{
+	static const uint8_t res[] = {
+		0x00, 0x0e, 0x57, 0x05, 0x08, 0x00, 0x77, 0x62,
+		0x83, 0x33, 0x66, 0x44, 0x88, 0x17, 0x01, 0x23 };
+	struct msgb *msg, *in_msg;
+	printf("Testing creating Layer3\n");
+
+	in_msg = msgb_alloc_headroom(512, 128, "foo");
+	in_msg->l3h = in_msg->data;
+	msgb_v_put(in_msg, 0x23);
+
+	msg = gsm0808_create_layer3(in_msg, 0x1122, 0x2244, 0x3366, 0x4488);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+	msgb_free(in_msg);
+}
+
+static void test_create_reset()
+{
+	static const uint8_t res[] = { 0x00, 0x04, 0x30, 0x04, 0x01, 0x20 };
+	struct msgb *msg;
+
+	printf("Testing creating Reset\n");
+	msg = gsm0808_create_reset();
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_clear_command()
+{
+	static const uint8_t res[] = { 0x20, 0x04, 0x01, 0x23 };
+	struct msgb *msg;
+
+	printf("Testing creating Clear Command\n");
+	msg = gsm0808_create_clear_command(0x23);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_clear_complete()
+{
+	static const uint8_t res[] = { 0x00, 0x01, 0x21 };
+	struct msgb *msg;
+
+	printf("Testing creating Clear Complete\n");
+	msg = gsm0808_create_clear_complete();
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_cipher_complete()
+{
+	static const uint8_t res1[] = {
+		0x00, 0x08, 0x55, 0x20, 0x03, 0x23, 0x42, 0x21, 0x2c, 0x04 };
+	static const uint8_t res2[] = { 0x00, 0x03, 0x55, 0x2c, 0x04};
+	struct msgb *l3, *msg;
+
+	printf("Testing creating Cipher Complete\n");
+	l3 = msgb_alloc_headroom(512, 128, "l3h");
+	l3->l3h = l3->data;
+	msgb_v_put(l3, 0x23);
+	msgb_v_put(l3, 0x42);
+	msgb_v_put(l3, 0x21);
+
+	/* with l3 data */
+	msg = gsm0808_create_cipher_complete(l3, 4);
+	VERIFY(msg, res1, ARRAY_SIZE(res1));
+	msgb_free(msg);
+
+	/* with l3 data but short */
+	l3->len -= 1;
+	l3->tail -= 1;
+	msg = gsm0808_create_cipher_complete(l3, 4);
+	VERIFY(msg, res2, ARRAY_SIZE(res2));
+	msgb_free(msg);
+
+	/* without l3 data */
+	msg = gsm0808_create_cipher_complete(NULL, 4);
+	VERIFY(msg, res2, ARRAY_SIZE(res2));
+	msgb_free(msg);
+
+
+	msgb_free(l3);
+}
+
+static void test_create_cipher_reject()
+{
+	static const uint8_t res[] = { 0x00, 0x02, 0x59, 0x23 };
+	struct msgb *msg;
+
+	printf("Testing creating Cipher Reject\n");
+	msg = gsm0808_create_cipher_reject(0x23);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_cm_u()
+{
+	static const uint8_t res[] = { 0x00, 0x02, 0x54, 0x23 };
+	struct msgb *msg;
+	const uint8_t cm = 0x23;
+
+	printf("Testing creating CM U\n");
+	msg = gsm0808_create_classmark_update(&cm, 1);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_sapi_reject()
+{
+	static const uint8_t res[] = { 0x00, 0x03, 0x25, 0x03, 0x25 };
+	struct msgb *msg;
+
+	printf("Testing creating SAPI Reject\n");
+	msg = gsm0808_create_sapi_reject(3);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_ass_compl()
+{
+	static const uint8_t res1[] = {
+		0x00, 0x09, 0x02, 0x15, 0x23, 0x21, 0x42, 0x2c,
+		0x11, 0x40, 0x22 };
+	static const uint8_t res2[] = {
+		0x00, 0x07, 0x02, 0x15, 0x23, 0x21, 0x42, 0x2c, 0x11};
+	struct msgb *msg;
+
+	printf("Testing creating Assignment Complete\n");
+	msg = gsm0808_create_assignment_completed(0x23, 0x42, 0x11, 0x22);
+	VERIFY(msg, res1, ARRAY_SIZE(res1));
+	msgb_free(msg);
+
+	msg = gsm0808_create_assignment_completed(0x23, 0x42, 0x11, 0);
+	VERIFY(msg, res2, ARRAY_SIZE(res2));
+	msgb_free(msg);
+}
+
+static void test_create_ass_fail()
+{
+	static const uint8_t res1[] = { 0x00, 0x04, 0x03, 0x04, 0x01, 0x23 };
+	static const uint8_t res2[] = {
+		0x00, 0x06, 0x03, 0x04, 0x01, 0x23, 0x15, 0x02};
+	uint8_t rr_res = 2;
+	struct msgb *msg;
+
+	printf("Testing creating Assignment Failure\n");
+	msg = gsm0808_create_assignment_failure(0x23, NULL);
+	VERIFY(msg, res1, ARRAY_SIZE(res1));
+	msgb_free(msg);
+
+	msg = gsm0808_create_assignment_failure(0x23, &rr_res);
+	VERIFY(msg, res2, ARRAY_SIZE(res2));
+	msgb_free(msg);
+}
+
+static void test_create_clear_rqst()
+{
+	static const uint8_t res[] = { 0x00, 0x04, 0x22, 0x04, 0x01, 0x23 };
+	struct msgb *msg;
+
+	printf("Testing creating Clear Request\n");
+	msg = gsm0808_create_clear_rqst(0x23);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+}
+
+static void test_create_dtap()
+{
+	static const uint8_t res[] = { 0x01, 0x03, 0x02, 0x23, 0x42 };
+	struct msgb *msg, *l3;
+
+	printf("Testing creating DTAP\n");
+	l3 = msgb_alloc_headroom(512, 128, "test");
+	l3->l3h = l3->data;
+	msgb_v_put(l3, 0x23);
+	msgb_v_put(l3, 0x42);
+
+	msg = gsm0808_create_dtap(l3, 0x3);
+	VERIFY(msg, res, ARRAY_SIZE(res));
+	msgb_free(msg);
+	msgb_free(l3);
+}
+
+static void test_prepend_dtap()
+{
+	static const uint8_t res[] = { 0x01, 0x03, 0x02, 0x23, 0x42 };
+	struct msgb *in_msg;
+
+	printf("Testing prepend DTAP\n");
+
+	in_msg = msgb_alloc_headroom(512, 128, "test");
+	msgb_v_put(in_msg, 0x23);
+	msgb_v_put(in_msg, 0x42);
+
+	gsm0808_prepend_dtap_header(in_msg, 0x3);
+	in_msg->l3h = in_msg->data;
+	VERIFY(in_msg, res, ARRAY_SIZE(res));
+	msgb_free(in_msg);
+}
+
+int main(int argc, char **argv)
+{
+	printf("Testing generation of GSM0808 messages\n");
+	test_create_layer3();
+	test_create_reset();
+	test_create_clear_command();
+	test_create_clear_complete();
+	test_create_cipher_complete();
+	test_create_cipher_reject();
+	test_create_cm_u();
+	test_create_sapi_reject();
+	test_create_ass_compl();
+	test_create_ass_fail();
+	test_create_clear_rqst();
+	test_create_dtap();
+	test_prepend_dtap();
+
+	printf("Done\n");
+	return EXIT_SUCCESS;
+}