bsc: Move transaction.c from the libbsc to the libmsc

The BSC code does not use transactions, move it to the libmsc.
diff --git a/openbsc/src/libmsc/Makefile.am b/openbsc/src/libmsc/Makefile.am
index 17213ca..8d5034c 100644
--- a/openbsc/src/libmsc/Makefile.am
+++ b/openbsc/src/libmsc/Makefile.am
@@ -15,5 +15,6 @@
 			token_auth.c \
 			ussd.c \
 			vty_interface_layer3.c \
+			transaction.c \
 			osmo_msc.c
 
diff --git a/openbsc/src/libmsc/transaction.c b/openbsc/src/libmsc/transaction.c
new file mode 100644
index 0000000..8a181b7
--- /dev/null
+++ b/openbsc/src/libmsc/transaction.c
@@ -0,0 +1,151 @@
+/* GSM 04.07 Transaction handling */
+
+/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <openbsc/transaction.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/mncc.h>
+#include <openbsc/debug.h>
+#include <osmocom/core/talloc.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/gsm_04_08.h>
+#include <openbsc/mncc.h>
+#include <openbsc/paging.h>
+#include <openbsc/osmo_msc.h>
+
+void *tall_trans_ctx;
+
+void _gsm48_cc_trans_free(struct gsm_trans *trans);
+
+struct gsm_trans *trans_find_by_id(struct gsm_subscriber *subscr,
+				   uint8_t proto, uint8_t trans_id)
+{
+	struct gsm_trans *trans;
+	struct gsm_network *net = subscr->net;
+
+	llist_for_each_entry(trans, &net->trans_list, entry) {
+		if (trans->subscr == subscr &&
+		    trans->protocol == proto &&
+		    trans->transaction_id == trans_id)
+			return trans;
+	}
+	return NULL;
+}
+
+struct gsm_trans *trans_find_by_callref(struct gsm_network *net,
+					uint32_t callref)
+{
+	struct gsm_trans *trans;
+
+	llist_for_each_entry(trans, &net->trans_list, entry) {
+		if (trans->callref == callref)
+			return trans;
+	}
+	return NULL;
+}
+
+struct gsm_trans *trans_alloc(struct gsm_subscriber *subscr,
+			      uint8_t protocol, uint8_t trans_id,
+			      uint32_t callref)
+{
+	struct gsm_trans *trans;
+
+	DEBUGP(DCC, "subscr=%p, subscr->net=%p\n", subscr, subscr->net);
+
+	trans = talloc_zero(tall_trans_ctx, struct gsm_trans);
+	if (!trans)
+		return NULL;
+
+	trans->subscr = subscr;
+	subscr_get(trans->subscr);
+
+	trans->protocol = protocol;
+	trans->transaction_id = trans_id;
+	trans->callref = callref;
+
+	llist_add_tail(&trans->entry, &subscr->net->trans_list);
+
+	return trans;
+}
+
+void trans_free(struct gsm_trans *trans)
+{
+	switch (trans->protocol) {
+	case GSM48_PDISC_CC:
+		_gsm48_cc_trans_free(trans);
+		break;
+	case GSM48_PDISC_SMS:
+		_gsm411_sms_trans_free(trans);
+		break;
+	}
+
+	/* FIXME: implement a sane way to stop this. */
+	if (!trans->conn && trans->paging_request) {
+		LOGP(DNM, LOGL_ERROR,
+		     "Transaction freed while paging for sub: %llu\n",
+		     trans->subscr->id);
+		trans->paging_request = NULL;
+	}
+
+	if (trans->subscr)
+		subscr_put(trans->subscr);
+
+	llist_del(&trans->entry);
+
+	if (trans->conn)
+		msc_release_connection(trans->conn);
+
+
+	talloc_free(trans);
+}
+
+/* allocate an unused transaction ID for the given subscriber
+ * in the given protocol using the ti_flag specified */
+int trans_assign_trans_id(struct gsm_subscriber *subscr,
+			  uint8_t protocol, uint8_t ti_flag)
+{
+	struct gsm_network *net = subscr->net;
+	struct gsm_trans *trans;
+	unsigned int used_tid_bitmask = 0;
+	int i, j, h;
+
+	if (ti_flag)
+		ti_flag = 0x8;
+
+	/* generate bitmask of already-used TIDs for this (subscr,proto) */
+	llist_for_each_entry(trans, &net->trans_list, entry) {
+		if (trans->subscr != subscr ||
+		    trans->protocol != protocol ||
+		    trans->transaction_id == 0xff)
+			continue;
+		used_tid_bitmask |= (1 << trans->transaction_id);
+	}
+
+	/* find a new one, trying to go in a 'circular' pattern */
+	for (h = 6; h > 0; h--)
+		if (used_tid_bitmask & (1 << (h | ti_flag)))
+			break;
+	for (i = 0; i < 7; i++) {
+		j = ((h + i) % 7) | ti_flag;
+		if ((used_tid_bitmask & (1 << j)) == 0)
+			return j;
+	}
+
+	return -1;
+}