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Diffstat (limited to 'openbsc/src/rtp_proxy.c')
-rw-r--r--openbsc/src/rtp_proxy.c227
1 files changed, 222 insertions, 5 deletions
diff --git a/openbsc/src/rtp_proxy.c b/openbsc/src/rtp_proxy.c
index bfd494856..f9207d661 100644
--- a/openbsc/src/rtp_proxy.c
+++ b/openbsc/src/rtp_proxy.c
@@ -24,6 +24,10 @@
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
+#include <sys/time.h> /* gettimeofday() */
+#include <unistd.h> /* get..() */
+#include <time.h> /* clock() */
+#include <sys/utsname.h> /* uname() */
#include <openbsc/talloc.h>
#include <openbsc/gsm_data.h>
@@ -57,6 +61,169 @@ struct rtcp_hdr {
#define RTCP_IE_CNAME 1
+/* according to RFC 3550 */
+struct rtp_hdr {
+ u_int8_t csrc_count:4,
+ extension:1,
+ padding:1,
+ version:2;
+ u_int8_t payload_type:7,
+ marker:1;
+ u_int16_t sequence;
+ u_int32_t timestamp;
+ u_int32_t ssrc;
+} __attribute__((packed));
+
+struct rtp_x_hdr {
+ u_int16_t by_profile;
+ u_int16_t length;
+} __attribute__((packed));
+
+#define RTP_VERSION 2
+
+#define RTP_PT_GSM_FULL 3
+
+/* decode an rtp frame and create a new buffer with payload */
+static int rtp_decode(struct msgb *msg, u_int32_t callref, struct msgb **data)
+{
+ struct msgb *new_msg;
+ struct gsm_data_frame *frame;
+ struct rtp_hdr *rtph = (struct rtp_hdr *)msg->data;
+ struct rtp_x_hdr *rtpxh;
+ u_int8_t *payload;
+ int payload_len;
+ int msg_type;
+ int x_len;
+
+ if (msg->len < 12) {
+ DEBUGPC(DMUX, "received RTP frame too short (len = %d)\n",
+ msg->len);
+ return -EINVAL;
+ }
+ if (rtph->version != RTP_VERSION) {
+ DEBUGPC(DMUX, "received RTP version %d not supported.\n",
+ rtph->version);
+ return -EINVAL;
+ }
+ payload = msg->data + sizeof(struct rtp_hdr) + (rtph->csrc_count << 2);
+ payload_len = msg->len - sizeof(struct rtp_hdr) - (rtph->csrc_count << 2);
+ if (payload_len < 0) {
+ DEBUGPC(DMUX, "received RTP frame too short (len = %d, "
+ "csrc count = %d)\n", msg->len, rtph->csrc_count);
+ return -EINVAL;
+ }
+ if (rtph->extension) {
+ if (payload_len < sizeof(struct rtp_x_hdr)) {
+ DEBUGPC(DMUX, "received RTP frame too short for "
+ "extension header\n");
+ return -EINVAL;
+ }
+ rtpxh = (struct rtp_x_hdr *)payload;
+ x_len = ntohs(rtpxh->length) * 4 + sizeof(struct rtp_x_hdr);
+ payload += x_len;
+ payload_len -= x_len;
+ if (payload_len < 0) {
+ DEBUGPC(DMUX, "received RTP frame too short, "
+ "extension header exceeds frame length\n");
+ return -EINVAL;
+ }
+ }
+ if (rtph->padding) {
+ if (payload_len < 0) {
+ DEBUGPC(DMUX, "received RTP frame too short for "
+ "padding length\n");
+ return -EINVAL;
+ }
+ payload_len -= payload[payload_len - 1];
+ if (payload_len < 0) {
+ DEBUGPC(DMUX, "received RTP frame with padding "
+ "greater than payload\n");
+ return -EINVAL;
+ }
+ }
+
+ switch (rtph->payload_type) {
+ case RTP_PT_GSM_FULL:
+ msg_type = GSM_TCHF_FRAME;
+ if (payload_len != 33) {
+ DEBUGPC(DMUX, "received RTP full rate frame with "
+ "payload length != 32 (len = %d)\n",
+ payload_len);
+ return -EINVAL;
+ }
+ break;
+ default:
+ DEBUGPC(DMUX, "received RTP frame with unknown payload "
+ "type %d\n", rtph->payload_type);
+ return -EINVAL;
+ }
+
+ new_msg = msgb_alloc(sizeof(struct gsm_data_frame) + payload_len,
+ "GSM-DATA");
+ if (!new_msg)
+ return -ENOMEM;
+ frame = (struct gsm_data_frame *)(new_msg->data);
+ frame->msg_type = msg_type;
+ frame->callref = callref;
+ memcpy(frame->data, payload, payload_len);
+ msgb_put(new_msg, sizeof(struct gsm_data_frame) + payload_len);
+
+ *data = new_msg;
+ return 0;
+}
+
+/* encode and send a rtp frame */
+int rtp_send_frame(struct rtp_socket *rs, struct gsm_data_frame *frame)
+{
+ struct rtp_sub_socket *rss = &rs->rtp;
+ struct msgb *msg;
+ struct rtp_hdr *rtph;
+ int payload_type;
+ int payload_len;
+ int duration; /* in samples */
+
+ if (rs->tx_action != RTP_SEND_DOWNSTREAM) {
+ /* initialize sequences */
+ rs->tx_action = RTP_SEND_DOWNSTREAM;
+ rs->transmit.ssrc = rand();
+ rs->transmit.sequence = random();
+ rs->transmit.timestamp = random();
+ }
+
+ switch (frame->msg_type) {
+ case GSM_TCHF_FRAME:
+ payload_type = RTP_PT_GSM_FULL;
+ payload_len = 33;
+ duration = 160;
+ break;
+ default:
+ DEBUGPC(DMUX, "unsupported message type %d\n",
+ frame->msg_type);
+ return -EINVAL;
+ }
+
+ msg = msgb_alloc(sizeof(struct rtp_hdr) + payload_len, "RTP-GSM-FULL");
+ if (!msg)
+ return -ENOMEM;
+ rtph = (struct rtp_hdr *)msg->data;
+ rtph->version = RTP_VERSION;
+ rtph->padding = 0;
+ rtph->extension = 0;
+ rtph->csrc_count = 0;
+ rtph->marker = 0;
+ rtph->payload_type = payload_type;
+ rtph->sequence = htons(rs->transmit.sequence++);
+ rtph->timestamp = htonl(rs->transmit.timestamp);
+ rs->transmit.timestamp += duration;
+ rtph->ssrc = htonl(rs->transmit.ssrc);
+ memcpy(msg->data + sizeof(struct rtp_hdr), frame->data, payload_len);
+ msgb_put(msg, sizeof(struct rtp_hdr) + payload_len);
+ msgb_enqueue(&rss->tx_queue, msg);
+ rss->bfd.when |= BSC_FD_WRITE;
+
+ return 0;
+}
+
/* iterate over all chunks in one RTCP message, look for CNAME IEs and
* replace all of those with 'new_cname' */
static int rtcp_sdes_cname_mangle(struct msgb *msg, struct rtcp_hdr *rh,
@@ -123,10 +290,16 @@ static int rtcp_mangle(struct msgb *msg, struct rtp_socket *rs)
if (!mangle_rtcp_cname)
return 0;
+ printf("RTCP\n");
/* iterate over list of RTCP messages */
rtph = (struct rtcp_hdr *)msg->data;
- while ((void *)rtph + sizeof(*rtph) < (void *)msg->data + msg->len) {
+ while ((void *)rtph + sizeof(*rtph) <= (void *)msg->data + msg->len) {
old_len = (ntohs(rtph->length) + 1) * 4;
+ if ((void *)rtph + old_len > (void *)msg->data + msg->len) {
+ DEBUGPC(DMUX, "received RTCP packet too short for "
+ "length element\n");
+ return -EINVAL;
+ }
if (rtph->type == RTCP_TYPE_SDES) {
char new_cname[255];
strncpy(new_cname, inet_ntoa(rss->sin_local.sin_addr),
@@ -148,6 +321,7 @@ 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 msgb *new_msg;
struct rtp_sub_socket *other_rss;
if (!msg)
@@ -184,13 +358,40 @@ static int rtp_socket_read(struct rtp_socket *rs, struct rtp_sub_socket *rss)
break;
case RTP_RECV_UPSTREAM:
- case RTP_NONE:
- /* FIXME: other cases */
- DEBUGP(DMUX, "unhandled action: %d\n", rs->rx_action);
+ if (!rs->receive.callref || !rs->receive.net) {
+ rc = -EIO;
+ goto out_free;
+ }
+ if (rss->bfd.priv_nr == RTP_PRIV_RTCP) {
+ if (!mangle_rtcp_cname) {
+ msgb_free(msg);
+ break;
+ }
+ /* modify RTCP SDES CNAME */
+ rc = rtcp_mangle(msg, rs);
+ if (rc < 0)
+ goto out_free;
+ msgb_enqueue(&rss->tx_queue, msg);
+ rss->bfd.when |= BSC_FD_WRITE;
+ break;
+ }
+ if (rss->bfd.priv_nr != RTP_PRIV_RTP) {
+ rc = -EINVAL;
+ goto out_free;
+ }
+ rc = rtp_decode(msg, rs->receive.callref, &new_msg);
+ if (rc < 0)
+ goto out_free;
+ msgb_free(msg);
+ msgb_enqueue(&rs->receive.net->upqueue, new_msg);
+ break;
+
+ case RTP_NONE: /* if socket exists, but disabled by app */
+ msgb_free(msg);
break;
}
- return rc;
+ return 0;
out_free:
msgb_free(msg);
@@ -420,6 +621,22 @@ int rtp_socket_proxy(struct rtp_socket *this, struct rtp_socket *other)
return 0;
}
+/* bind RTP/RTCP socket to application */
+int rtp_socket_upstream(struct rtp_socket *this, struct gsm_network *net, u_int32_t callref)
+{
+ DEBUGP(DMUX, "rtp_socket_proxy(this=%p, callref=%lu)\n",
+ this, callref);
+
+ if (callref) {
+ this->rx_action = RTP_RECV_UPSTREAM;
+ this->receive.net = net;
+ this->receive.callref = callref;
+ } else
+ this->rx_action = RTP_NONE;
+
+ return 0;
+}
+
static void free_tx_queue(struct rtp_sub_socket *rss)
{
struct msgb *msg;
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-19 10:02:07 +0000