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-rw-r--r--openbsc/include/openbsc/rtp_proxy.h70
-rw-r--r--openbsc/src/rtp_proxy.c282
2 files changed, 352 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 */
diff --git a/openbsc/src/rtp_proxy.c b/openbsc/src/rtp_proxy.c
new file mode 100644
index 000000000..f7eb8b835
--- /dev/null
+++ b/openbsc/src/rtp_proxy.c
@@ -0,0 +1,282 @@
+/* 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 <errno.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <openbsc/talloc.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/msgb.h>
+#include <openbsc/select.h>
+#include <openbsc/rtp_proxy.h>
+
+static LLIST_HEAD(rtp_sockets);
+
+enum rtp_bfd_priv {
+ RTP_PRIV_NONE,
+ RTP_PRIV_RTP,
+ RTP_PRIV_RTCP
+};
+
+#define RTP_ALLOC_SIZE 1500
+
+/* read from incoming RTP/RTCP socket */
+static int rtp_socket_read(struct rtp_socket *rs, struct rtp_sub_socket *rss)
+{
+ int rc;
+ struct msgb *msg = msgb_alloc(RTP_ALLOC_SIZE, "RTP/RTCP");
+ struct rtp_sub_socket *other_rss;
+
+ if (!msg)
+ return -ENOMEM;
+
+ rc = read(rss->bfd.fd, msg->data, RTP_ALLOC_SIZE);
+ if (rc <= 0) {
+ rss->bfd.when &= ~BSC_FD_READ;
+ return rc;
+ }
+
+ msgb_put(msg, rc);
+
+ switch (rs->rx_action) {
+ case RTP_PROXY:
+ if (rss->bfd.priv_nr == RTP_PRIV_RTP)
+ other_rss = &rs->proxy.other_sock->rtp;
+ else if (rss->bfd.priv_nr == RTP_PRIV_RTCP)
+ other_rss = &rs->proxy.other_sock->rtcp;
+ else {
+ msgb_free(msg);
+ return -EINVAL;
+ }
+ msgb_enqueue(&other_rss->tx_queue, msg);
+ other_rss->bfd.when |= BSC_FD_WRITE;
+ break;
+ /* FIXME: other cases */
+ }
+
+ return rc;
+}
+
+/* write from tx_queue to RTP/RTCP socket */
+static int rtp_socket_write(struct rtp_socket *rs, struct rtp_sub_socket *rss)
+{
+ struct msgb *msg;
+ int written;
+
+ msg = msgb_dequeue(&rss->tx_queue);
+ if (!msg) {
+ rss->bfd.when &= ~BSC_FD_WRITE;
+ return 0;
+ }
+
+ written = write(rss->bfd.fd, msg->data, msg->len);
+ if (written < msg->len) {
+ perror("short write");
+ msgb_free(msg);
+ return -EIO;
+ }
+
+ msgb_free(msg);
+
+ return 0;
+}
+
+
+/* callback for the select.c:bfd_* layer */
+static int rtp_bfd_cb(struct bsc_fd *bfd, unsigned int flags)
+{
+ struct rtp_socket *rs = bfd->data;
+ struct rtp_sub_socket *rss;
+
+ switch (bfd->priv_nr) {
+ case RTP_PRIV_RTP:
+ rss = &rs->rtp;
+ break;
+ case RTP_PRIV_RTCP:
+ rss = &rs->rtcp;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (flags & BSC_FD_READ)
+ rtp_socket_read(rs, rss);
+
+ if (flags & BSC_FD_WRITE)
+ rtp_socket_write(rs, rss);
+
+ return 0;
+}
+
+static void init_rss(struct rtp_sub_socket *rss,
+ struct rtp_socket *rs, int fd, int priv_nr)
+{
+ /* initialize bfd */
+ rss->bfd.fd = fd;
+ rss->bfd.data = rs;
+ rss->bfd.priv_nr = priv_nr;
+ rss->bfd.cb = rtp_bfd_cb;
+}
+
+struct rtp_socket *rtp_socket_create(void)
+{
+ int rc;
+ struct rtp_socket *rs;
+
+ rs = talloc_zero(tall_bsc_ctx, struct rtp_socket);
+ if (!rs)
+ return NULL;
+
+ INIT_LLIST_HEAD(&rs->rtp.tx_queue);
+ INIT_LLIST_HEAD(&rs->rtcp.tx_queue);
+
+ rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ if (rc < 0)
+ goto out_free;
+
+ init_rss(&rs->rtp, rs, rc, RTP_PRIV_RTP);
+ rc = bsc_register_fd(&rs->rtp.bfd);
+ if (rc < 0)
+ goto out_rtp_socket;
+
+ rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ if (rc < 0)
+ goto out_rtp_bfd;
+
+ init_rss(&rs->rtcp, rs, rc, RTP_PRIV_RTCP);
+ rc = bsc_register_fd(&rs->rtcp.bfd);
+ if (rc < 0)
+ goto out_rtcp_socket;
+
+ return rs;
+
+out_rtcp_socket:
+ close(rs->rtcp.bfd.fd);
+out_rtp_bfd:
+ bsc_unregister_fd(&rs->rtp.bfd);
+out_rtp_socket:
+ close(rs->rtp.bfd.fd);
+out_free:
+ talloc_free(rs);
+ return NULL;
+}
+
+static int rtp_sub_socket_bind(struct rtp_sub_socket *rss, u_int32_t ip,
+ u_int16_t port)
+{
+ rss->sin_local.sin_family = AF_INET;
+ rss->sin_local.sin_addr.s_addr = htonl(ip);
+ rss->sin_local.sin_port = htons(port);
+ rss->bfd.when |= BSC_FD_READ;
+
+ return bind(rss->bfd.fd, (struct sockaddr *)&rss->sin_local,
+ sizeof(rss->sin_local));
+}
+
+#define RTP_PORT_BASE 30000
+static u_int16_t next_udp_port = RTP_PORT_BASE;
+
+/* bind a RTP socket to a local address */
+int rtp_socket_bind(struct rtp_socket *rs, u_int32_t ip)
+{
+ int rc;
+
+ /* try to bind to a consecutive pair of ports */
+ for (next_udp_port; next_udp_port < 0xffff; next_udp_port += 2) {
+ rc = rtp_sub_socket_bind(&rs->rtp, ip, next_udp_port);
+ if (rc != 0)
+ continue;
+
+ rc = rtp_sub_socket_bind(&rs->rtcp, ip, next_udp_port+1);
+ if (rc == 0)
+ break;
+ }
+ if (rc < 0)
+ return rc;
+
+ return ntohs(rs->rtp.sin_local.sin_port);
+}
+
+static int rtp_sub_socket_connect(struct rtp_sub_socket *rss,
+ u_int32_t ip, u_int16_t port)
+{
+ rss->sin_remote.sin_family = AF_INET;
+ rss->sin_remote.sin_addr.s_addr = htonl(ip);
+ rss->sin_remote.sin_port = htons(port);
+
+ return connect(rss->bfd.fd, (struct sockaddr *) &rss->sin_remote,
+ sizeof(rss->sin_remote));
+}
+
+/* 'connect' a RTP socket to a remote peer */
+int rtp_socket_connect(struct rtp_socket *rs, u_int32_t ip, u_int16_t port)
+{
+ int rc;
+
+ rc = rtp_sub_socket_connect(&rs->rtp, ip, port);
+ if (rc < 0)
+ return rc;
+
+ return rtp_sub_socket_connect(&rs->rtcp, ip, port+1);
+}
+
+/* bind two RTP/RTCP sockets together */
+int rtp_socket_proxy(struct rtp_socket *this, struct rtp_socket *other)
+{
+ this->rx_action = RTP_PROXY;
+ this->proxy.other_sock = other;
+
+ other->rx_action = RTP_PROXY;
+ other->proxy.other_sock = this;
+
+ return 0;
+}
+
+static void free_tx_queue(struct rtp_sub_socket *rss)
+{
+ struct msgb *msg;
+
+ while ((msg = msgb_dequeue(&rss->tx_queue)))
+ msgb_free(msg);
+}
+
+int rtp_socket_free(struct rtp_socket *rs)
+{
+
+ /* make sure we don't leave references dangling to us */
+ if (rs->rx_action == RTP_PROXY &&
+ rs->proxy.other_sock)
+ rs->proxy.other_sock->proxy.other_sock = NULL;
+
+ bsc_unregister_fd(&rs->rtp.bfd);
+ close(rs->rtp.bfd.fd);
+ free_tx_queue(&rs->rtp);
+
+ bsc_unregister_fd(&rs->rtcp.bfd);
+ close(rs->rtcp.bfd.fd);
+ free_tx_queue(&rs->rtcp);
+
+ talloc_free(rs);
+
+ return 0;
+}
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