tests/rlcmac: also verify encoding of MS RA Capability
The main idea of this change is to demonstrate a weakness of the
CSN.1 codec that most likely causes a unit test breakage in [1].
The problem seems to be that the transitional structures, where
the CSN.1 decoder stores the results, do not contain any details
about presence of the optional fields (such as M_UINT_OR_NULL).
In other words, it's impossible to know whether some optional
field is omitted in the encoded message (NULL), or is it just
set to 0. This means that the encoder will always include all
optional fields, even if they're not present in the original
message.
[1] Ibb4cbd3f5865415fd547e95fc24ff31df1aed4c0
Change-Id: Ic46d6e56768f516203d27d8e7a5adb77afdf32b7
diff --git a/tests/rlcmac/RLCMACTest.cpp b/tests/rlcmac/RLCMACTest.cpp
index de63fe6..b8506b1 100644
--- a/tests/rlcmac/RLCMACTest.cpp
+++ b/tests/rlcmac/RLCMACTest.cpp
@@ -214,12 +214,16 @@
msgb_free(m);
}
+int encode_gsm_ra_cap(bitvec * vector, MS_Radio_Access_capability_t * data);
+
void testRAcap(void *test_ctx)
{
printf("*** %s ***\n", __func__);
MS_Radio_Access_capability_t data;
memset(&data, 0, sizeof(data));
- bitvec *vector = bitvec_alloc(23, test_ctx);
+ bitvec *bv_dec = bitvec_alloc(23, test_ctx);
+ bitvec *bv_enc = bitvec_alloc(23, test_ctx);
+ unsigned int len_dec, len_enc;
int rc;
/*
MS RA capability 1
@@ -235,9 +239,10 @@
.... ..00 011. .... = GPRS multislot class: Max Rx-Slot/TDMA:2 Max Tx-Slot/TDMA:2 Max-Sum-Slot/TDMA:3 Tta:3 Ttb:2 Tra:3 Trb:1 Type:1 (3)
...0 .... = GPRS Extended Dynamic Allocation Capability: Not Implemented
*/
- bitvec_unhex(vector, "13a5146200");
+ bitvec_unhex(bv_dec, "13a5146200");
- rc = decode_gsm_ra_cap(vector, &data);
+ printf("=== Test decoding of MS RA Capability ===\n");
+ rc = decode_gsm_ra_cap(bv_dec, &data);
OSMO_ASSERT(rc == 0);
/* Make sure there's 1 value (currently fails due to failed decoding) */
@@ -247,14 +252,30 @@
printf("GPRS multislot class = %u\n", Decoding::get_ms_class_by_capability(&data));
printf("EGPRS multislot class = %u\n", Decoding::get_egprs_ms_class_by_capability(&data));
+ /* Test encoding of decoded MS RA Capability */
+ printf("=== Test encoding of MS RA Capability ===\n");
+ rc = encode_gsm_ra_cap(bv_enc, &data);
+ printf("encode_gsm_ra_cap() returns %d\n", rc);
+
+ bv_dec->cur_bit = 4;
+ len_dec = bitvec_get_uint(bv_dec, 7);
+ bv_enc->cur_bit = 4;
+ len_enc = bitvec_get_uint(bv_enc, 7);
+
+ /* NOTE: vector2 is expected to be different because there is actually no
+ * way to distinguish between NULL and 0 in MS_Radio_Access_capability_t.
+ * The difference is in length indicator: 29 bits vs 50 bits. */
+ printf("vector1 (len_ind=%u) = %s\n", len_dec, osmo_hexdump(bv_dec->data, bv_dec->data_len));
+ printf("vector2 (len_ind=%u) = %s\n", len_enc, osmo_hexdump(bv_enc->data, bv_enc->data_len));
+
/* Mangle the length indicator (set it to 21) */
unsigned int writeIndex = 4;
- rc = bitvec_write_field(vector, &writeIndex, 21, 7);
+ rc = bitvec_write_field(bv_dec, &writeIndex, 21, 7);
OSMO_ASSERT(rc == 0);
/* Make sure decoding attempt fails */
- printf("Test decoding of a malformed vector (short length indicator)\n");
- rc = decode_gsm_ra_cap(vector, &data);
+ printf("=== Test decoding of a malformed vector (short length indicator) ===\n");
+ rc = decode_gsm_ra_cap(bv_dec, &data);
printf("decode_gsm_ra_cap() returns %d\n", rc);
}