* add trau_mux implementation to relay from one incoming TRAU
channel to another one (simple voice call switching)
* add a way more generic E1 input layer, abstracting out the misdn
low-level interface. This also adds infrastructure for multiple TRX
in one BTS, as well as multiple BTS on one E1 link
* add a E1 subchannel multiplexer for sending multiple 16kbit sub-channels
one one 64kBps E1 channel
* add TRAU IDLE frame generation
* terminate bsc_hack in case there is a E1 / mISDN init error
* introduce 'e1_config.c' file with static configuration of our
E1 setup (which TRX/BTS is configured for which TEI/SAPI/E1). This should
later become a config file rather than a compiled C file.
WARNING: all this compiles but is not tested yet. Expect fix-up committs over
the next hours or so
diff --git a/src/subchan_demux.c b/src/subchan_demux.c
index da1b090..78ba2da 100644
--- a/src/subchan_demux.c
+++ b/src/subchan_demux.c
@@ -1,4 +1,4 @@
-/* A E1 sub-channel demultiplexer with TRAU frame sync */
+/* A E1 sub-channel (de)multiplexer with TRAU frame sync */
/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
* All Rights Reserved
@@ -26,8 +26,9 @@
#include <errno.h>
#include <openbsc/subchan_demux.h>
+#include <openbsc/trau_frame.h>
-static inline void append_bit(struct subch *sch, u_int8_t bit)
+static inline void append_bit(struct demux_subch *sch, u_int8_t bit)
{
sch->out_bitbuf[sch->out_idx++] = bit;
}
@@ -37,7 +38,7 @@
/* 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 subch *sch)
+static int sync_hdr_complete(struct demux_subch *sch)
{
int rc;
int bits_at_end = 0;
@@ -62,7 +63,7 @@
}
/* resynchronize to current location */
-static void resync_to_here(struct subch *sch)
+static void resync_to_here(struct demux_subch *sch)
{
#if 0
u_int8_t tmp[TRAU_FRAME_BITS];
@@ -98,7 +99,7 @@
dmx->chan_activ = 0;
for (i = 0; i < NR_SUBCH; i++) {
- struct subch *sch = &dmx->subch[i];
+ struct demux_subch *sch = &dmx->subch[i];
sch->out_idx = 0;
memset(sch->out_bitbuf, 0xff, sizeof(sch->out_bitbuf));
}
@@ -119,7 +120,7 @@
u_int8_t inbyte = data[i];
for (c = 0; c < NR_SUBCH; c++) {
- struct subch *sch = &dmx->subch[c];
+ struct demux_subch *sch = &dmx->subch[c];
u_int8_t bit;
/* ignore inactive subchannels */
@@ -177,3 +178,134 @@
dmx->chan_activ &= ~(1 << subch);
return 0;
}
+
+/* MULTIPLEXER */
+
+static int alloc_add_idle_frame(struct subch_mux *mx, int sch_nr)
+{
+ /* FIXME: allocate and initialize with idle pattern */
+ return subchan_mux_enqueue(mx, sch_nr, trau_idle_frame(),
+ TRAU_FRAME_BITS);
+}
+
+/* return the requested number of bits from the specified subchannel */
+static int get_subch_bits(struct subch_mux *mx, int subch,
+ u_int8_t *bits, int num_requested)
+{
+ struct mux_subch *sch = &mx->subch[subch];
+ int num_bits = 0;
+
+ while (num_bits < num_requested) {
+ struct subch_txq_entry *txe;
+ int num_bits_left;
+ int num_bits_thistime;
+
+ /* make sure we have a valid entry at top of tx queue.
+ * if not, add an idle frame */
+ if (llist_empty(&sch->tx_queue))
+ alloc_add_idle_frame(mx, subch);
+
+ if (llist_empty(&sch->tx_queue))
+ return -EIO;
+
+ txe = llist_entry(&sch->tx_queue, struct subch_txq_entry, list);
+ num_bits_left = txe->bit_len - txe->next_bit;
+
+ if (num_bits_left < num_requested)
+ num_bits_thistime = num_bits_left;
+ else
+ num_bits_thistime = num_requested;
+
+ /* pull the bits from the txe */
+ memcpy(bits + num_bits, txe->bits + txe->next_bit, num_requested);
+ txe->next_bit += num_bits_thistime;
+
+ /* free the tx_queue entry if it is fully consumed */
+ if (txe->next_bit >= txe->bit_len) {
+ llist_del(&txe->list);
+ free(txe);
+ }
+
+ /* increment global number of bits dequeued */
+ num_bits += num_bits_thistime;
+ }
+
+ return num_requested;
+}
+
+/* compact an array of 8 single-bit bytes into one byte of 8 bits */
+static u_int8_t compact_bits(u_int8_t *bits)
+{
+ u_int8_t ret = 0;
+ int i;
+
+ for (i = 0; i < 8; i++)
+ ret |= (bits[i] ? 1 : 0) << i;
+
+ return ret;
+}
+
+/* obtain a single output byte from the subchannel muxer */
+static int mux_output_byte(struct subch_mux *mx, u_int8_t *byte)
+{
+ u_int8_t bits[8];
+ 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);
+
+ if (!rc)
+ *byte = compact_bits(bits);
+
+ return rc;
+}
+
+/* Request the output of some muxed bytes from the subchan muxer */
+int subchan_mux_out(struct subch_mux *mx, u_int8_t *data, int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++) {
+ int rc;
+ rc = mux_output_byte(mx, &data[i]);
+ if (rc < 0)
+ break;
+ }
+ return i;
+}
+
+/* enqueue some data into the tx_queue of a given subchannel */
+int subchan_mux_enqueue(struct subch_mux *mx, int s_nr, const u_int8_t *data,
+ int len)
+{
+ struct mux_subch *sch = &mx->subch[s_nr];
+ struct subch_txq_entry *tqe = malloc(sizeof(*tqe) + len);
+
+ if (!tqe)
+ return -ENOMEM;
+
+ memset(tqe, 0, sizeof(*tqe));
+ tqe->bit_len = len;
+ memcpy(tqe->bits, data, len);
+
+ llist_add(&tqe->list, &sch->tx_queue);
+
+ return 0;
+}
+
+/* initialize one subchannel muxer instance */
+int subchan_mux_init(struct subch_mux *mx)
+{
+ int i;
+
+ memset(mx, 0, sizeof(*mx));
+ for (i = 0; i < NR_SUBCH; i++) {
+ struct mux_subch *sch = &mx->subch[i];
+ INIT_LLIST_HEAD(&sch->tx_queue);
+ }
+
+ return 0;
+}