edge: Add experimental support for uplink CRBB
Currently only uncompressed bitmaps (URBB) are supported in
PACKET UPLINK ACK/NACK messages.
Extend decode_egprs_acknack_bits to decode compressed bitmaps (CRBB),
too.
Note that this code is only active, if the macro WITH_CRBB_DECODING
is defined.
Sponsored-by: On-Waves ehf
diff --git a/src/decoding.cpp b/src/decoding.cpp
index f4cd880..7c20c48 100644
--- a/src/decoding.cpp
+++ b/src/decoding.cpp
@@ -23,6 +23,9 @@
extern "C" {
#include <osmocom/core/utils.h>
+#if WITH_CRBB_DECODING
+#include <osmocom/core/bitcomp.h>
+#endif
}
#include <arpa/inet.h>
@@ -548,37 +551,74 @@
num_blocks += implicitly_acked_blocks;
}
- if (have_bitmap) {
- /* next bit refers to V(Q) and thus is always zero (and not
- * transmitted) */
- bitvec_set_bit(bits, ZERO);
- num_blocks += 1;
+ if (!have_bitmap)
+ goto aborted;
- if (crbb_len > 0) {
- int old_len = bits->cur_bit;
- /*
- decode_t4_rle(bits, desc->CRBB, desc->CRBB_LENGTH,
- desc->CRBB_STARTING_COLOR_CODE);
- */
+ /* next bit refers to V(Q) and thus is always zero (and not
+ * transmitted) */
+ bitvec_set_bit(bits, ZERO);
+ num_blocks += 1;
- num_blocks += (bits->cur_bit - old_len);
+ if (crbb_len > 0) {
+ int old_len = bits->cur_bit;
+#if WITH_CRBB_DECODING
+#warning "Experimental CRBB decoding enabled"
+ struct bitvec crbb;
+ int rc;
+
+ crbb.data = (uint8_t *)desc->CRBB;
+ crbb.data_len = sizeof(desc->CRBB);
+ crbb.cur_bit = desc->CRBB_LENGTH;
+
+ rc = osmo_t4_decode(&crbb, desc->CRBB_STARTING_COLOR_CODE,
+ bits);
+
+ if (rc < 0) {
+ LOGP(DRLCMACUL, LOGL_NOTICE,
+ "Failed to decode CRBB: "
+ "length %d, data '%s'\n",
+ desc->CRBB_LENGTH,
+ osmo_hexdump(crbb.data, crbb.data_len));
+ /* We don't know the SSN offset for the URBB,
+ * return what we have so far and assume the
+ * bitmap has stopped here */
+ goto aborted;
}
+#else
+ LOGP(DRLCMACUL, LOGL_ERROR, "ERROR: CRBB not supported, "
+ "please set window size to 64\n");
- urbb.cur_bit = 0;
- urbb.data = (uint8_t *)desc->URBB;
- urbb.data_len = sizeof(desc->URBB);
+ /* We don't know the SSN offset for the URBB, return
+ * what we have so far and assume the bitmap has
+ * stopped here */
+ goto aborted;
+#endif
+ LOGP(DRLCMACDL, LOGL_DEBUG,
+ "CRBB len: %d, decoded len: %d, cc: %d, crbb: '%s'\n",
+ desc->CRBB_LENGTH, bits->cur_bit - old_len,
+ desc->CRBB_STARTING_COLOR_CODE,
+ osmo_hexdump(
+ desc->CRBB, (desc->CRBB_LENGTH + 7)/8)
+ );
- for (i = urbb_len; i > 0; i--) {
- /*
- * Set bit at the appropriate position (see 3GPP TS
- * 44.060 12.3.1)
- */
- int is_ack = bitvec_get_bit_pos(&urbb, i-1);
- bitvec_set_bit(bits, is_ack == 1 ? ONE : ZERO);
- }
- num_blocks += urbb_len;
+ num_blocks += (bits->cur_bit - old_len);
}
+ urbb.cur_bit = 0;
+ urbb.data = (uint8_t *)desc->URBB;
+ urbb.data_len = sizeof(desc->URBB);
+
+ for (i = urbb_len; i > 0; i--) {
+ /*
+ * Set bit at the appropriate position (see 3GPP TS
+ * 44.060 12.3.1)
+ */
+ int is_ack = bitvec_get_bit_pos(&urbb, i-1);
+ bitvec_set_bit(bits, is_ack == 1 ? ONE : ZERO);
+ }
+ num_blocks += urbb_len;
+
+aborted:
*bsn_begin = window->v_a();
*bsn_end = window->mod_sns(*bsn_begin + num_blocks);