diff options
Diffstat (limited to 'pjmedia/src/pjmedia/rtp.c')
| -rw-r--r-- | pjmedia/src/pjmedia/rtp.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/pjmedia/src/pjmedia/rtp.c b/pjmedia/src/pjmedia/rtp.c new file mode 100644 index 00000000..601c7d61 --- /dev/null +++ b/pjmedia/src/pjmedia/rtp.c @@ -0,0 +1,245 @@ +/* $Header: /pjproject-0.3/pjmedia/src/pjmedia/rtp.c 5 10/14/05 12:23a Bennylp $ */
+
+#include <pjmedia/rtp.h>
+#include <pj/log.h>
+#include <pj/os.h> /* pj_gettimeofday() */
+#include <pj/sock.h> /* pj_htonx, pj_htonx */
+#include <string.h> /* memset() */
+
+#define THIS_FILE "rtp.c"
+
+#define RTP_VERSION 2
+
+#define RTP_SEQ_MOD (1 << 16)
+#define MAX_DROPOUT ((pj_int16_t)3000)
+#define MAX_MISORDER ((pj_int16_t)100)
+#define MIN_SEQUENTIAL ((pj_int16_t)2)
+
+
+PJ_DEF(pj_status_t) pj_rtp_session_init( pj_rtp_session *ses,
+ int default_pt, pj_uint32_t sender_ssrc )
+{
+ PJ_LOG(4, (THIS_FILE, "pj_rtp_session_init: ses=%p, default_pt=%d, ssrc=0x%x",
+ ses, default_pt, sender_ssrc));
+
+ /* Check RTP header packing. */
+ if (sizeof(struct pj_rtp_hdr) != 12) {
+ pj_assert(!"Wrong RTP header packing!");
+ return PJ_RTP_ERR_RTP_PACKING;
+ }
+
+ /* If sender_ssrc is not specified, create from time value. */
+ if (sender_ssrc == 0 || sender_ssrc == (pj_uint32_t)-1) {
+ pj_time_val tv;
+
+ pj_gettimeofday(&tv);
+ sender_ssrc = (pj_uint32_t) pj_htonl(tv.sec);
+ } else {
+ sender_ssrc = pj_htonl(sender_ssrc);
+ }
+
+ /* Initialize session. */
+ ses->out_extseq = 0;
+ ses->peer_ssrc = 0;
+
+ /* Sequence number will be initialized when the first RTP packet is receieved. */
+
+ /* Build default header for outgoing RTP packet. */
+ memset(ses, 0, sizeof(*ses));
+ ses->out_hdr.v = RTP_VERSION;
+ ses->out_hdr.p = 0;
+ ses->out_hdr.x = 0;
+ ses->out_hdr.cc = 0;
+ ses->out_hdr.m = 0;
+ ses->out_hdr.pt = (pj_uint8_t) default_pt;
+ ses->out_hdr.seq = (pj_uint16_t) pj_htons( (pj_uint16_t)ses->out_extseq );
+ ses->out_hdr.ts = 0;
+ ses->out_hdr.ssrc = sender_ssrc;
+
+ /* Keep some arguments as session defaults. */
+ ses->out_pt = (pj_uint16_t) default_pt;
+
+ return PJ_SUCCESS;
+}
+
+
+PJ_DEF(pj_status_t) pj_rtp_encode_rtp( pj_rtp_session *ses, int pt, int m,
+ int payload_len, int ts_len,
+ const void **rtphdr, int *hdrlen )
+{
+ PJ_UNUSED_ARG(payload_len)
+
+ PJ_LOG(6, (THIS_FILE,
+ "pj_rtp_encode_rtp: ses=%p, pt=%d, m=%d, pt_len=%d, ts_len=%d",
+ ses, pt, m, payload_len, ts_len));
+
+ /* Update session. */
+ ses->out_extseq++;
+ ses->out_hdr.ts = pj_htonl(pj_ntohl(ses->out_hdr.ts)+ts_len);
+
+ /* Create outgoing header. */
+ ses->out_hdr.pt = (pj_uint8_t) ((pt == -1) ? ses->out_pt : pt);
+ ses->out_hdr.m = (pj_uint16_t) m;
+ ses->out_hdr.seq = pj_htons( (pj_uint16_t) ses->out_extseq);
+
+ /* Return values */
+ *rtphdr = &ses->out_hdr;
+ *hdrlen = sizeof(pj_rtp_hdr);
+
+ return PJ_SUCCESS;
+}
+
+
+PJ_DEF(pj_status_t) pj_rtp_decode_rtp( pj_rtp_session *ses,
+ const void *pkt, int pkt_len,
+ const pj_rtp_hdr **hdr,
+ const void **payload,
+ unsigned *payloadlen)
+{
+ int offset;
+
+ PJ_UNUSED_ARG(ses)
+
+ PJ_LOG(6, (THIS_FILE,
+ "pj_rtp_decode_rtp: ses=%p, pkt=%p, pkt_len=%d",
+ ses, pkt, pkt_len));
+
+ /* Assume RTP header at the start of packet. We'll verify this later. */
+ *hdr = (pj_rtp_hdr*)pkt;
+
+ /* Check RTP header sanity. */
+ if ((*hdr)->v != RTP_VERSION) {
+ PJ_LOG(4, (THIS_FILE, " invalid RTP version!"));
+ return PJ_RTP_ERR_INVALID_VERSION;
+ }
+
+ /* Payload is located right after header plus CSRC */
+ offset = sizeof(pj_rtp_hdr) + ((*hdr)->cc * sizeof(pj_uint32_t));
+
+ /* Adjust offset if RTP extension is used. */
+ if ((*hdr)->x) {
+ pj_rtp_ext_hdr *ext = (pj_rtp_ext_hdr*) (((pj_uint8_t*)pkt) + offset);
+ offset += (pj_ntohs(ext->length) * sizeof(pj_uint32_t));
+ }
+
+ /* Check that offset is less than packet size */
+ if (offset >= pkt_len)
+ return PJ_RTP_ERR_INVALID_PACKET;
+
+ /* Find and set payload. */
+ *payload = ((pj_uint8_t*)pkt) + offset;
+ *payloadlen = pkt_len - offset;
+
+ return PJ_SUCCESS;
+}
+
+
+PJ_DEF(pj_status_t) pj_rtp_session_update( pj_rtp_session *ses, const pj_rtp_hdr *hdr)
+{
+ int status;
+
+ /* Check SSRC. */
+ if (ses->peer_ssrc == 0) ses->peer_ssrc = pj_ntohl(hdr->ssrc);
+ /*
+ if (pj_ntohl(ses->peer_ssrc) != hdr->ssrc) {
+ PJ_LOG(4, (THIS_FILE, "pj_rtp_session_update: ses=%p, invalid ssrc 0x%p (!=0x%p)",
+ ses, pj_ntohl(hdr->ssrc), ses->peer_ssrc));
+ return PJ_RTP_ERR_INVALID_SSRC;
+ }
+ */
+
+ /* Check payload type. */
+ if (hdr->pt != ses->out_pt) {
+ PJ_LOG(4, (THIS_FILE, "pj_rtp_session_update: ses=%p, invalid payload type %d (!=%d)",
+ ses, hdr->pt, ses->out_pt));
+ return PJ_RTP_ERR_INVALID_PT;
+ }
+
+ /* Initialize sequence number on first packet received. */
+ if (ses->received == 0)
+ pj_rtp_seq_init( &ses->seq_ctrl, pj_ntohs(hdr->seq) );
+
+ /* Check sequence number to see if remote session has been restarted. */
+ status = pj_rtp_seq_update( &ses->seq_ctrl, pj_ntohs(hdr->seq));
+ if (status == PJ_RTP_ERR_SESSION_RESTARTED) {
+ pj_rtp_seq_restart( &ses->seq_ctrl, pj_ntohs(hdr->seq));
+ ++ses->received;
+ } else if (status == 0 || status == PJ_RTP_ERR_SESSION_PROBATION) {
+ ++ses->received;
+ }
+
+
+ return status;
+}
+
+
+void pj_rtp_seq_restart(pj_rtp_seq_session *sctrl, pj_uint16_t seq)
+{
+ sctrl->base_seq = seq;
+ sctrl->max_seq = seq;
+ sctrl->bad_seq = RTP_SEQ_MOD + 1;
+ sctrl->cycles = 0;
+}
+
+
+void pj_rtp_seq_init(pj_rtp_seq_session *sctrl, pj_uint16_t seq)
+{
+ pj_rtp_seq_restart(sctrl, seq);
+
+ sctrl->max_seq = (pj_uint16_t) (seq - 1);
+ sctrl->probation = MIN_SEQUENTIAL;
+}
+
+
+int pj_rtp_seq_update(pj_rtp_seq_session *sctrl, pj_uint16_t seq)
+{
+ pj_uint16_t udelta = (pj_uint16_t) (seq - sctrl->max_seq);
+
+ /*
+ * Source is not valid until MIN_SEQUENTIAL packets with
+ * sequential sequence numbers have been received.
+ */
+ if (sctrl->probation) {
+ /* packet is in sequence */
+ if (seq == sctrl->max_seq+ 1) {
+ sctrl->probation--;
+ sctrl->max_seq = seq;
+ if (sctrl->probation == 0) {
+ return PJ_RTP_ERR_SESSION_RESTARTED;
+ }
+ } else {
+ sctrl->probation = MIN_SEQUENTIAL - 1;
+ sctrl->max_seq = seq;
+ }
+ return PJ_RTP_ERR_SESSION_PROBATION;
+
+ } else if (udelta < MAX_DROPOUT) {
+ /* in order, with permissible gap */
+ if (seq < sctrl->max_seq) {
+ /* Sequence number wrapped - count another 64K cycle. */
+ sctrl->cycles += RTP_SEQ_MOD;
+ }
+ sctrl->max_seq = seq;
+
+ } else if (udelta <= (RTP_SEQ_MOD - MAX_MISORDER)) {
+ /* the sequence number made a very large jump */
+ if (seq == sctrl->bad_seq) {
+ /*
+ * Two sequential packets -- assume that the other side
+ * restarted without telling us so just re-sync
+ * (i.e., pretend this was the first packet).
+ */
+ return PJ_RTP_ERR_SESSION_RESTARTED;
+ }
+ else {
+ sctrl->bad_seq = (seq + 1) & (RTP_SEQ_MOD-1);
+ return PJ_RTP_ERR_BAD_SEQUENCE;
+ }
+ } else {
+ /* duplicate or reordered packet */
+ }
+
+ return 0;
+}
+
+
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