Add LAPDm collision test (contention resolution on network side)
diff --git a/tests/lapd/lapd_test.c b/tests/lapd/lapd_test.c
index 1f986bc..1a06cb1 100644
--- a/tests/lapd/lapd_test.c
+++ b/tests/lapd/lapd_test.c
@@ -179,6 +179,32 @@
return 0;
}
+static int send_sabm(struct lapdm_channel *chan, int second_ms)
+{
+ struct osmo_phsap_prim pp;
+ struct msgb *msg;
+ int rc;
+
+ msg = msgb_alloc_headroom(128, 64, "PH-DATA.ind");
+ osmo_prim_init(&pp.oph, SAP_GSM_PH, PRIM_PH_DATA,
+ PRIM_OP_INDICATION, msg);
+ /* copy over actual MAC block */
+ msg->l2h = msgb_put(msg, 23);
+ msg->l2h[0] = 0x01;
+ msg->l2h[1] = 0x3f;
+ msg->l2h[2] = 0x01 | (sizeof(cm) << 2);
+ memcpy(msg->l2h + 3, cm_padded, sizeof(cm_padded));
+ msg->l2h[3] += second_ms; /* alter message, for second mobile */
+
+ /* LAPDm requires those... */
+ pp.u.data.chan_nr = 0;
+ pp.u.data.link_id = 0;
+ /* feed into the LAPDm code of libosmogsm */
+ rc = lapdm_phsap_up(&pp.oph, &chan->lapdm_dcch);
+ ASSERT(rc == 0 || rc == -EBUSY);
+ return 0;
+}
+
/*
* I get called from the LAPDm code when something was sent my way...
*/
@@ -417,6 +443,49 @@
lapdm_channel_exit(&bts_to_ms_channel);
}
+static void test_lapdm_contention_resolution()
+{
+ printf("I test contention resultion by having two mobiles collide and "
+ "first mobile repeating SABM.\n");
+
+ int rc;
+ struct lapdm_polling_state test_state;
+ struct osmo_phsap_prim pp;
+
+ /* Configure LAPDm on both sides */
+ struct lapdm_channel bts_to_ms_channel;
+ memset(&bts_to_ms_channel, 0, sizeof(bts_to_ms_channel));
+
+ memset(&test_state, 0, sizeof(test_state));
+ test_state.bts = &bts_to_ms_channel;
+
+ /* BTS to MS in polling mode */
+ lapdm_channel_init(&bts_to_ms_channel, LAPDM_MODE_BTS);
+ lapdm_channel_set_flags(&bts_to_ms_channel, LAPDM_ENT_F_POLLING_ONLY);
+ lapdm_channel_set_l1(&bts_to_ms_channel, NULL, &test_state);
+ lapdm_channel_set_l3(&bts_to_ms_channel, bts_to_ms_tx_cb, &test_state);
+
+ /* Send SABM MS 1, we must get UA */
+ send_sabm(&bts_to_ms_channel, 0);
+ rc = lapdm_phsap_dequeue_prim(&bts_to_ms_channel.lapdm_dcch, &pp);
+ CHECK_RC(rc);
+ ASSERT(memcmp(pp.oph.msg->l2h, ua, ARRAY_SIZE(ua)) == 0);
+
+ /* Send SABM MS 2, we must get nothing, due to collision */
+ send_sabm(&bts_to_ms_channel, 1);
+ rc = lapdm_phsap_dequeue_prim(&bts_to_ms_channel.lapdm_dcch, &pp);
+ ASSERT(rc == -ENODEV);
+
+ /* Send SABM MS 1 again, we must get UA gain */
+ send_sabm(&bts_to_ms_channel, 0);
+ rc = lapdm_phsap_dequeue_prim(&bts_to_ms_channel.lapdm_dcch, &pp);
+ CHECK_RC(rc);
+ ASSERT(memcmp(pp.oph.msg->l2h, ua, ARRAY_SIZE(ua)) == 0);
+
+ /* clean up */
+ lapdm_channel_exit(&bts_to_ms_channel);
+}
+
int main(int argc, char **argv)
{
osmo_init_logging(&info);