Initially implement the new osmo-mgw and libosmo-mgcp

Leave the old osmo-bsc_mgcp and libosmo-legacy-mgcp as it is; on a copy thereof
(added by a previous commit), apply changes to initially implement the new
osmo-mgw.

Adjust build system and debian packaging to accomodate the new libosmo-mgcp and
osmo-mgw.

The main differences:

*) use a list to manage rtp connections.

Aggregate all rtp related information inside a single struct.

Use a linked list to manage the both connections (net and bts).
The idea behind using a list is that we might support conference
calls at some later point.

Store the linked list in struct mgcp_endpoint, have a private linked
list for each endpoint. The list contains connection items which are
implemented in struct mgcp_conn. A connection is allocated and freed
using the functions in mgcp_conn.c. A connection is allocated on the
reception of a CRCX command and freed with the reception of a DLCX
command.

*) remove external transcoder feature

Fortunatelly the external transcoder feature is not needed
anymore. This patch removes the related code.

*) vty: get rid of CONN_BTS and CONN_NET

Since the new connection model does not make a difference
between BTS and NET connections the VTY should not use
the fixed CONN_BTS and CONN_NET constants.

- Handle the conns list inside the endpoint directly
- introduce function to dump basic rtp connection info
- introduce human readable names for connections

Parts of the code adjusted to use generalized connections instead of explicit
BTS/NET ones:

- teach mgcp_send_dummy() to send dummy packets to any RTP connection
- network: generalize mgcp_bind_net/bts_rtp_port()
- network: generalize mgcp_send()
- tap: generalize call tapping feature
- stat: generalize statistics
- Replace rtp_data_net() and rtp_data_bts() with generalized rtp_data_rx()

*) mgcp_protocol.c fixes:

- check ci string before it is converted:
  In case of missing ci, a nullpointer is delivered to strtoul().
  Add a function that takes ci, checks it and converts it to an
  uint32_t. Use the return code to react on missing ci.
- output error message on missing CI.
- when parsing the mode, print log message when mode is missing.
- use mode_orig when mode is missing.
- fix ptime formatstring to use %u rather than %d.
- cosmetic: log when connection is deleted on DLCX.
- change loglevels of CRCX, MDCX, DLCX events from DEBUG to NOTICE.

*) mgcp_test

- apply rename of strline_r() to mgcp_strline().
- MGCP command macros:
  - Add 'I: 1' parameters.
  - Use proper port numbers:
    from m=audio 0 RTP/AVP 126
    to   m=audio 16002 RTP/AVP 128
  - Change ptime to 'a=ptime:40' because this is what the MGW currently
    returns.  CRCX generally feed a ptime:40 and this is expected to be
    returned.
- struct mgcp_test: Use only one ptype, there are no explicit BTS and NET
  endpoints anymore.
  Hence remove one column from tests[].
- test_messages():
  - Enable: remove '#if 0'
  - Remove concept of BTS and NET endpoints: test only one conn, as they are
    now interchangeable anyway.
  - remove endpoint init, now done internally.
  - add false asserts in error cases.
- test_retransmission():
  - remove endpoint init, now done internally.
  - add false asserts in error cases.
- test_packet_error_detection():
  - Remove concept of BTS and NET endpoints: test only one conn, as they are
    now interchangeable anyway. Use arbitrary conn ids (e.g. 4711).
  - remove endpoint init, now done internally.
  - add false assert in error case.
  - Assert that a conn really vanishes on DLCX, previously the conn would
    remain and just be unused, now it is actually discarded.
- test_no_cycle()
  - Remove concept of BTS and NET endpoints: test only one conn, as they are
    now interchangeable anyway. Use arbitrary conn ids (e.g. 4711).
- test_no_name()
  - Enable: remove '#if 0'.
  - remove endpoint init, now done internally.
  - add false assert in error case.
- mgcp_test.ok: adjust expected results to status quo:
  - We now see two dummy packets instead of one, now sent to both sides because
    we don't know of BTS or NET side. (maybe drop dummy packets later...)
  - packet duration, conn mode: now sane defaults show instead of unset.
- various whitespace and formatting changes from lindent.

Change-Id: Ie008599136c7ed8a0dfbb0cf803188975a499fc5
diff --git a/include/osmocom/mgcp/mgcp_conn.h b/include/osmocom/mgcp/mgcp_conn.h
new file mode 100644
index 0000000..e0ae021
--- /dev/null
+++ b/include/osmocom/mgcp/mgcp_conn.h
@@ -0,0 +1,40 @@
+/* Message connection list handling */
+
+/*
+ * (C) 2017 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * 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/>.
+ *
+ */
+
+#pragma once
+
+#include <osmocom/mgcp/mgcp_internal.h>
+#include <osmocom/core/linuxlist.h>
+#include <inttypes.h>
+
+struct mgcp_conn *mgcp_conn_alloc(void *ctx, struct mgcp_endpoint *endp,
+				  uint32_t id, enum mgcp_conn_type type,
+				  char *name);
+struct mgcp_conn *mgcp_conn_get(struct mgcp_endpoint *endp, uint32_t id);
+struct mgcp_conn_rtp *mgcp_conn_get_rtp(struct mgcp_endpoint *endp,
+					uint32_t id);
+void mgcp_conn_free(struct mgcp_endpoint *endp, uint32_t id);
+void mgcp_conn_free_oldest(struct mgcp_endpoint *endp);
+void mgcp_conn_free_all(struct mgcp_endpoint *endp);
+char *mgcp_conn_dump(struct mgcp_conn *conn);
+struct mgcp_conn *mgcp_find_dst_conn(struct mgcp_conn *conn);