ciphering: Handle ciphering support for A5/3 correctly

This was found and debugged by Sylvain. The BTS will always support
A5/0 so we do not keep track of that, the first bit of the flags is
used for A5/1, second for A5/2... but for RSL there is an offset to
go from RSL to A5(x). Add a testcase and change the code.

3 files changed, 139 insertions, 0 deletions

diff --git a/tests/cipher/Makefile.am b/tests/cipher/Makefile.am
new file mode 100644
index 00000000..bd6f15b3
--- /dev/null
+++ b/tests/cipher/Makefile.am
@@ -0,0 +1,8 @@
+INCLUDES = $(all_includes) -I$(top_srcdir)/include -I$(OPENBSC_INCDIR)
+AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(LIBOSMOTRAU_CFLAGS)
+LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOTRAU_LIBS) -lortp
+noinst_PROGRAMS = cipher_test
+EXTRA_DIST = cipher_test.ok
+
+cipher_test_SOURCES = cipher_test.c
+cipher_test_LDADD = $(top_builddir)/src/common/libbts.a $(LDADD)
diff --git a/tests/cipher/cipher_test.c b/tests/cipher/cipher_test.c
new file mode 100644
index 00000000..7d037c21
--- /dev/null
+++ b/tests/cipher/cipher_test.c
@@ -0,0 +1,130 @@
+/* (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 Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <osmo-bts/bts.h>
+#include <osmo-bts/logging.h>
+#include <osmo-bts/paging.h>
+#include <osmo-bts/gsm_data.h>
+
+#include <osmocom/core/talloc.h>
+
+#include <errno.h>
+#include <unistd.h>
+
+static struct gsm_bts *bts;
+static struct gsm_bts_role_bts *btsb;
+int pcu_direct = 0;
+
+#define ASSERT_TRUE(rc) \
+	if (!(rc)) { \
+		printf("Assert failed in %s:%d.\n",  \
+		       __FILE__, __LINE__);          \
+		abort();			     \
+	}
+
+static void test_cipher_parsing(void)
+{
+	int i;
+
+	btsb->support.ciphers = 0;
+
+	/* always support A5/0 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x0) == -ENOTSUP);
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x1) == 1); /* A5/0 */
+	for (i = 2; i <= 8; ++i) {
+		ASSERT_TRUE(bts_supports_cipher(btsb, i) == 0);
+	}
+
+	/* checking default A5/1 to A5/3 support */
+	btsb->support.ciphers = CIPHER_A5(1) | CIPHER_A5(2) | CIPHER_A5(3);
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x0) == -ENOTSUP);
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x1) == 1); /* A5/0 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x2) == 1); /* A5/1 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x3) == 1); /* A5/2 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x4) == 1); /* A5/3 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x5) == 0); /* A5/4 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x6) == 0); /* A5/5 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x7) == 0); /* A5/6 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x8) == 0); /* A5/7 */
+	ASSERT_TRUE(bts_supports_cipher(btsb, 0x9) == -ENOTSUP);
+}
+
+int main(int argc, char **argv)
+{
+	void *tall_msgb_ctx;
+
+	tall_bts_ctx = talloc_named_const(NULL, 1, "OsmoBTS context");
+	tall_msgb_ctx = talloc_named_const(tall_bts_ctx, 1, "msgb");
+	msgb_set_talloc_ctx(tall_msgb_ctx);
+
+	bts_log_init(NULL);
+
+	bts = gsm_bts_alloc(tall_bts_ctx);
+	if (bts_init(bts) < 0) {
+		fprintf(stderr, "unable to to open bts\n");
+		exit(1);
+	}
+
+	btsb = bts_role_bts(bts);
+	test_cipher_parsing();
+	printf("Success\n");
+
+	return 0;
+}
+
+/* stub to link */
+const uint8_t abis_mac[6] = { 0,1,2,3,4,5 };
+const char *software_version = "0815";
+
+int bts_model_chg_adm_state(struct gsm_bts *bts, struct gsm_abis_mo *mo,
+			    void *obj, uint8_t adm_state)
+{ return 0; }
+int bts_model_init(struct gsm_bts *bts)
+{ return 0; }
+int bts_model_apply_oml(struct gsm_bts *bts, struct msgb *msg,
+			struct tlv_parsed *new_attr, void *obj)
+{ return 0; }
+int bts_model_rsl_chan_rel(struct gsm_lchan *lchan)
+{ return 0;}
+
+int bts_model_rsl_deact_sacch(struct gsm_lchan *lchan)
+{ return 0; }
+
+int bts_model_trx_deact_rf(struct gsm_bts_trx *trx)
+{ return 0; }
+int bts_model_check_oml(struct gsm_bts *bts, uint8_t msg_type,
+			struct tlv_parsed *old_attr, struct tlv_parsed *new_attr,
+			void *obj)
+{ return 0; }
+int bts_model_opstart(struct gsm_bts *bts, struct gsm_abis_mo *mo,
+		      void *obj)
+{ return 0; }
+int bts_model_rsl_chan_act(struct gsm_lchan *lchan, struct tlv_parsed *tp)
+{ return 0; }
+int bts_model_rsl_mode_modify(struct gsm_lchan *lchan)
+{ return 0; }
+void bts_model_rtp_rx_cb(struct osmo_rtp_socket *rs, const uint8_t *rtp_pl,
+			 unsigned int rtp_pl_len) {}
+
+int l1if_pdch_req(struct gsm_bts_trx_ts *ts, int is_ptcch, uint32_t fn,
+        uint16_t arfcn, uint8_t block_nr, uint8_t *data, uint8_t len)
+{ return 0; }
+
+uint32_t trx_get_hlayer1(struct gsm_bts_trx *trx)
+{ return 0; }
diff --git a/tests/cipher/cipher_test.ok b/tests/cipher/cipher_test.ok
new file mode 100644
index 00000000..35821117
--- /dev/null
+++ b/tests/cipher/cipher_test.ok
@@ -0,0 +1 @@
+Success