add new rtp_proxy code, but not use it yet

The rtp_proxy.[ch] code is intended to be used as a transparent
RTP/RTCP proxy, relaying the media streams from one ip.access BTS
to another.  In an 'ideal' network, this is obviously not needed,
since the BTS's can send those streams directly between each other.

However, for debugging, 'lawful interception', transcoding or interfacing
a TRAU/E1 based BTS, we actually need to process those RTP streams
ourselves.

1 files changed, 70 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/rtp_proxy.h b/openbsc/include/openbsc/rtp_proxy.h
new file mode 100644
index 000000000..e9fc157cf
--- /dev/null
+++ b/openbsc/include/openbsc/rtp_proxy.h
@@ -0,0 +1,70 @@
+#ifndef _RTP_PROXY_H
+#define _RTP_PROXY_H
+
+/* RTP proxy handling for ip.access nanoBTS */
+
+/* (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 General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+
+#include <netinet/in.h>
+
+#include <openbsc/linuxlist.h>
+#include <openbsc/select.h>
+
+enum rtp_rx_action {
+	RTP_NONE,
+	RTP_PROXY,
+	RTP_RECV_UPSTREAM,
+};
+
+struct rtp_sub_socket {
+	struct sockaddr_in sin_local;
+	struct sockaddr_in sin_remote;
+
+	struct bsc_fd bfd;
+	/* linked list of to-be-transmitted msgb's */
+	struct llist_head tx_queue;
+};
+
+struct rtp_socket {
+	struct llist_head list;
+
+	struct rtp_sub_socket rtp;
+	struct rtp_sub_socket rtcp;
+
+	/* what should we do on receive? */
+	enum rtp_rx_action rx_action;
+	union {
+		struct {
+			struct rtp_socket *other_sock;
+		} proxy;
+		struct {
+			void (*recv_cb)(struct msgb *msg);
+		} receive;
+	};
+};
+
+struct rtp_socket *rtp_socket_create(void);
+int rtp_socket_bind(struct rtp_socket *rs, u_int32_t ip);
+int rtp_socket_connect(struct rtp_socket *rs, u_int32_t ip, u_int16_t port);
+int rtp_socket_proxy(struct rtp_socket *this, struct rtp_socket *other);
+int rtp_socket_free(struct rtp_socket *rs);
+
+#endif /* _RTP_PROXY_H */