"the big fix", of the E1 subchannel [de]multiplexer. I don't even remember how
many bugs I fixed during the last couple of hours. It was never working at
any time before.
diff --git a/src/subchan_demux.c b/src/subchan_demux.c
index d8bf29f..86ddc86 100644
--- a/src/subchan_demux.c
+++ b/src/subchan_demux.c
@@ -27,6 +27,7 @@
#include <openbsc/subchan_demux.h>
#include <openbsc/trau_frame.h>
+#include <openbsc/debug.h>
static inline void append_bit(struct demux_subch *sch, u_int8_t bit)
{
@@ -38,55 +39,25 @@
/* check if we have just completed the 16 bit zero sync header,
* in accordance with GSM TS 08.60 Chapter 4.8.1 */
-static int sync_hdr_complete(struct demux_subch *sch)
+static int sync_hdr_complete(struct demux_subch *sch, u_int8_t bit)
{
- int rc;
- int bits_at_end = 0;
- int bits_at_front;
-
- if (sch->out_idx < SYNC_HDR_BITS)
- bits_at_end = SYNC_HDR_BITS - sch->out_idx;
- bits_at_front = sch->out_idx;
+ if (bit == 0)
+ sch->consecutive_zeros++;
+ else
+ sch->consecutive_zeros = 0;
- if (bits_at_end) {
- rc = memcmp(sch->out_bitbuf + sizeof(sch->out_bitbuf) - bits_at_end,
- nullbytes, bits_at_end);
- if (rc)
- return 0;
+ if (sch->consecutive_zeros >= SYNC_HDR_BITS) {
+ sch->consecutive_zeros = 0;
+ return 1;
}
- rc = memcmp(sch->out_bitbuf + sch->out_idx, nullbytes,
- bits_at_front);
- if (rc)
- return 0;
-
- return 1;
+
+ return 0;
}
/* resynchronize to current location */
static void resync_to_here(struct demux_subch *sch)
{
-#if 0
- u_int8_t tmp[TRAU_FRAME_BITS];
- int sync_hdr_start = sch->out_idx - SYNC_HDR_BITS;
- int bytes_at_end;
-
- /* first make copy of old bitbuf */
- memcpy(tmp, sch->out_bitbuf, sizeof(tmp));
-
- if (sync_hdr_start < 0)
- sync_hdr_start += TRAU_FRAME_BITS;
-
- bytes_at_end = TRAU_FRAME_BITS - sync_hdr_start;
-
- /* copy part after sync_hdr_start */
- memcpy(sch->out_bitbuf, tmp + sync_hdr_start, bytes_at_end);
-
- /* copy part before sync_hdr_start */
- memcpy(sch->out_bitbuf + bytes_at_end, tmp,
- SYNC_HDR_BITS - bytes_at_end);
-#else
memset(sch->out_bitbuf, 0, SYNC_HDR_BITS);
-#endif
/* set index in a way that we can continue receiving bits after
* the end of the SYNC header */
@@ -121,29 +92,32 @@
for (c = 0; c < NR_SUBCH; c++) {
struct demux_subch *sch = &dmx->subch[c];
+ u_int8_t inbits;
u_int8_t bit;
/* ignore inactive subchannels */
if (!(dmx->chan_activ & (1 << c)))
continue;
+ inbits = inbyte >> ((3-c)*2);
+
/* two bits for each subchannel */
- if ((inbyte >> (c * 2)) & 0x01)
+ if (inbits & 0x01)
bit = 1;
else
bit = 0;
append_bit(sch, bit);
- if (sync_hdr_complete(sch))
+ if (sync_hdr_complete(sch, bit))
resync_to_here(sch);
- if ((inbyte >> (c * 2)) & 0x02)
+ if (inbits & 0x02)
bit = 1;
else
bit = 0;
append_bit(sch, bit);
- if (sync_hdr_complete(sch))
+ if (sync_hdr_complete(sch, bit))
resync_to_here(sch);
/* FIXME: verify the first bit in octet 2, 4, 6, ...
@@ -183,7 +157,7 @@
static int alloc_add_idle_frame(struct subch_mux *mx, int sch_nr)
{
- /* FIXME: allocate and initialize with idle pattern */
+ /* allocate and initialize with idle pattern */
return subchan_mux_enqueue(mx, sch_nr, trau_idle_frame(),
TRAU_FRAME_BITS);
}
@@ -217,7 +191,7 @@
num_bits_thistime = num_requested;
/* pull the bits from the txe */
- memcpy(bits + num_bits, txe->bits + txe->next_bit, num_requested);
+ memcpy(bits + num_bits, txe->bits + txe->next_bit, num_bits_thistime);
txe->next_bit += num_bits_thistime;
/* free the tx_queue entry if it is fully consumed */
@@ -234,7 +208,7 @@
}
/* compact an array of 8 single-bit bytes into one byte of 8 bits */
-static u_int8_t compact_bits(u_int8_t *bits)
+static u_int8_t compact_bits(const u_int8_t *bits)
{
u_int8_t ret = 0;
int i;
@@ -252,13 +226,12 @@
int rc;
/* combine two bits of every subchan */
- rc = get_subch_bits(mx, 0, &bits[0], 2);
- rc = get_subch_bits(mx, 1, &bits[2], 2);
- rc = get_subch_bits(mx, 2, &bits[4], 2);
- rc = get_subch_bits(mx, 3, &bits[6], 2);
+ rc = get_subch_bits(mx, 3, &bits[0], 2);
+ rc = get_subch_bits(mx, 2, &bits[2], 2);
+ rc = get_subch_bits(mx, 1, &bits[4], 2);
+ rc = get_subch_bits(mx, 0, &bits[6], 2);
- if (!rc)
- *byte = compact_bits(bits);
+ *byte = compact_bits(bits);
return rc;
}