[Asterisk-cvs] asterisk rtp.c,1.146,1.147
russell
russell
Wed Oct 12 16:50:34 CDT 2005
Update of /usr/cvsroot/asterisk
In directory mongoose.digium.com:/tmp/cvs-serv13905
Modified Files:
rtp.c
Log Message:
fix some formatting and add some comments (issue #5403)
Index: rtp.c
===================================================================
RCS file: /usr/cvsroot/asterisk/rtp.c,v
retrieving revision 1.146
retrieving revision 1.147
diff -u -d -r1.146 -r1.147
--- rtp.c 14 Sep 2005 20:46:49 -0000 1.146
+++ rtp.c 12 Oct 2005 20:45:18 -0000 1.147
@@ -16,12 +16,11 @@
* at the top of the source tree.
*/
-/*
- *
- * Real-time Protocol Support
- * Supports RTP and RTCP with Symmetric RTP support for NAT
- * traversal
+/*!
+ * \file rtp.c
+ * \brief Supports RTP and RTCP with Symmetric RTP support for NAT traversal.
*
+ * RTP is deffined in RFC 3550.
*/
#include <stdio.h>
@@ -59,7 +58,7 @@
#define RTP_MTU 1200
-static int dtmftimeout = 3000; /* 3000 samples */
+static int dtmftimeout = 3000; /* 3000 samples */
static int rtpstart = 0;
static int rtpend = 0;
@@ -87,6 +86,7 @@
char resp;
struct ast_frame f;
unsigned char rawdata[8192 + AST_FRIENDLY_OFFSET];
+ /*! Synchronization source, RFC 3550, page 10. */
unsigned int ssrc;
unsigned int lastts;
unsigned int lastdigitts;
@@ -101,13 +101,16 @@
unsigned int dtmfduration;
int nat;
unsigned int flags;
+ /*! Socket representation of the local endpoint. */
struct sockaddr_in us;
+ /*! Socket representation of the remote endpoint. */
struct sockaddr_in them;
struct timeval rxcore;
struct timeval txcore;
struct timeval dtmfmute;
struct ast_smoother *smoother;
int *ioid;
+ /*! Sequence number, RFC 3550, page 13. */
unsigned short seqno;
unsigned short rxseqno;
struct sched_context *sched;
@@ -115,16 +118,30 @@
void *data;
ast_rtp_callback callback;
struct rtpPayloadType current_RTP_PT[MAX_RTP_PT];
- int rtp_lookup_code_cache_isAstFormat; /* a cache for the result of rtp_lookup_code(): */
+ /*! a cache for the result of rtp_lookup_code(): */
+ int rtp_lookup_code_cache_isAstFormat;
int rtp_lookup_code_cache_code;
int rtp_lookup_code_cache_result;
int rtp_offered_from_local;
struct ast_rtcp *rtcp;
};
+/*!
+ * \brief Structure defining an RTCP session.
+ *
+ * The concept "RTCP session" is not defined in RFC 3550, but since
+ * this structure is analogous to ast_rtp, which tracks a RTP session,
+ * it is logical to think of this as a RTCP session.
+ *
+ * RTCP packet is defined on page 9 of RFC 3550.
+ *
+ */
struct ast_rtcp {
- int s; /* Socket */
+ /*! Socket */
+ int s;
+ /*! Socket representation of the local endpoint. */
struct sockaddr_in us;
+ /*! Socket representation of the remote endpoint. */
struct sockaddr_in them;
};
@@ -230,9 +247,17 @@
return f;
}
-/* process_rfc2833: Process RTP DTMF and events according to RFC 2833:
- "RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals"
-*/
+/*!
+ * \brief Process RTP DTMF and events according to RFC 2833.
+ *
+ * RFC 2833 is "RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals".
+ *
+ * \param rtp
+ * \param data
+ * \param len
+ * \param seqno
+ * \returns
+ */
static struct ast_frame *process_rfc2833(struct ast_rtp *rtp, unsigned char *data, int len, unsigned int seqno)
{
unsigned int event;
@@ -282,8 +307,11 @@
return f;
}
-/*--- process_rfc3389: Process Comfort Noise RTP.
- This is incomplete at the moment.
+/*!
+ * \brief Process Comfort Noise RTP.
+ *
+ * This is incomplete at the moment.
+ *
*/
static struct ast_frame *process_rfc3389(struct ast_rtp *rtp, unsigned char *data, int len)
{
@@ -483,7 +511,7 @@
ast_verbose("Got RTP packet from %s:%d (type %d, seq %d, ts %d, len %d)\n"
, ast_inet_ntoa(iabuf, sizeof(iabuf), sin.sin_addr), ntohs(sin.sin_port), payloadtype, seqno, timestamp,res - hdrlen);
- rtpPT = ast_rtp_lookup_pt(rtp, payloadtype);
+ rtpPT = ast_rtp_lookup_pt(rtp, payloadtype);
if (!rtpPT.isAstFormat) {
/* This is special in-band data that's not one of our codecs */
if (rtpPT.code == AST_RTP_DTMF) {
@@ -503,37 +531,37 @@
duration &= 0xFFFF;
ast_verbose("Got rfc2833 RTP packet from %s:%d (type %d, seq %d, ts %d, len %d, mark %d, event %08x, end %d, duration %d) \n", ast_inet_ntoa(iabuf, sizeof(iabuf), sin.sin_addr), ntohs(sin.sin_port), payloadtype, seqno, timestamp, res - hdrlen, (mark?1:0), event, ((event_end & 0x80)?1:0), duration);
}
- if (rtp->lasteventseqn <= seqno || rtp->resp == 0 || (rtp->lasteventseqn >= 65530 && seqno <= 6)) {
- f = process_rfc2833(rtp, rtp->rawdata + AST_FRIENDLY_OFFSET + hdrlen, res - hdrlen, seqno);
- rtp->lasteventseqn = seqno;
- } else
+ if (rtp->lasteventseqn <= seqno || rtp->resp == 0 || (rtp->lasteventseqn >= 65530 && seqno <= 6)) {
+ f = process_rfc2833(rtp, rtp->rawdata + AST_FRIENDLY_OFFSET + hdrlen, res - hdrlen, seqno);
+ rtp->lasteventseqn = seqno;
+ } else
f = NULL;
- if (f)
- return f;
- else
+ if (f)
+ return f;
+ else
return &null_frame;
- } else if (rtpPT.code == AST_RTP_CISCO_DTMF) {
- /* It's really special -- process it the Cisco way */
- if (rtp->lasteventseqn <= seqno || rtp->resp == 0 || (rtp->lasteventseqn >= 65530 && seqno <= 6)) {
- f = process_cisco_dtmf(rtp, rtp->rawdata + AST_FRIENDLY_OFFSET + hdrlen, res - hdrlen);
- rtp->lasteventseqn = seqno;
- } else
+ } else if (rtpPT.code == AST_RTP_CISCO_DTMF) {
+ /* It's really special -- process it the Cisco way */
+ if (rtp->lasteventseqn <= seqno || rtp->resp == 0 || (rtp->lasteventseqn >= 65530 && seqno <= 6)) {
+ f = process_cisco_dtmf(rtp, rtp->rawdata + AST_FRIENDLY_OFFSET + hdrlen, res - hdrlen);
+ rtp->lasteventseqn = seqno;
+ } else
f = NULL;
- if (f)
+ if (f)
return f;
else
return &null_frame;
- } else if (rtpPT.code == AST_RTP_CN) {
- /* Comfort Noise */
- f = process_rfc3389(rtp, rtp->rawdata + AST_FRIENDLY_OFFSET + hdrlen, res - hdrlen);
- if (f)
+ } else if (rtpPT.code == AST_RTP_CN) {
+ /* Comfort Noise */
+ f = process_rfc3389(rtp, rtp->rawdata + AST_FRIENDLY_OFFSET + hdrlen, res - hdrlen);
+ if (f)
return f;
else
return &null_frame;
- } else {
- ast_log(LOG_NOTICE, "Unknown RTP codec %d received\n", payloadtype);
- return &null_frame;
- }
+ } else {
+ ast_log(LOG_NOTICE, "Unknown RTP codec %d received\n", payloadtype);
+ return &null_frame;
+ }
}
rtp->f.subclass = rtpPT.code;
if (rtp->f.subclass < AST_FORMAT_MAX_AUDIO)
@@ -862,6 +890,11 @@
return s;
}
+/*!
+ * \brief Initialize a new RTCP session.
+ *
+ * \returns The newly initialized RTCP session.
+ */
static struct ast_rtcp *ast_rtcp_new(void)
{
struct ast_rtcp *rtcp;
@@ -903,16 +936,21 @@
rtp->sched = sched;
rtp->rtcp = ast_rtcp_new();
}
- /* Find us a place */
+
+ /* Select a random port number in the range of possible RTP */
x = (rand() % (rtpend-rtpstart)) + rtpstart;
x = x & ~1;
+ /* Save it for future references. */
startplace = x;
+ /* Iterate tring to bind that port and incrementing it otherwise untill a port was found or no ports are available. */
for (;;) {
/* Must be an even port number by RTP spec */
rtp->us.sin_port = htons(x);
rtp->us.sin_addr = addr;
+ /* If there's rtcp, initialize it as well. */
if (rtp->rtcp)
rtp->rtcp->us.sin_port = htons(x + 1);
+ /* Try to bind it/them. */
if (!(first = bind(rtp->s, (struct sockaddr *)&rtp->us, sizeof(rtp->us))) &&
(!rtp->rtcp || !bind(rtp->rtcp->s, (struct sockaddr *)&rtp->rtcp->us, sizeof(rtp->rtcp->us))))
break;
@@ -922,6 +960,7 @@
rtp->s = rtp_socket();
}
if (errno != EADDRINUSE) {
+ /* We got an error that wasn't expected, abort! */
ast_log(LOG_ERROR, "Unexpected bind error: %s\n", strerror(errno));
close(rtp->s);
if (rtp->rtcp) {
@@ -931,10 +970,15 @@
free(rtp);
return NULL;
}
+ /* The port was used, increment it (by two). */
x += 2;
+ /* Did we go over the limit ? */
if (x > rtpend)
+ /* then, start from the begingig. */
x = (rtpstart + 1) & ~1;
+ /* Check if we reached the place were we started. */
if (x == startplace) {
+ /* If so, there's no ports available. */
ast_log(LOG_ERROR, "No RTP ports remaining. Can't setup media stream for this call.\n");
close(rtp->s);
if (rtp->rtcp) {
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