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/* 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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