1/**********
2This library is free software; you can redistribute it and/or modify it under
3the terms of the GNU Lesser General Public License as published by the
4Free Software Foundation; either version 3 of the License, or (at your
5option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
6
7This library is distributed in the hope that it will be useful, but WITHOUT
8ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
9FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
10more details.
11
12You should have received a copy of the GNU Lesser General Public License
13along with this library; if not, write to the Free Software Foundation, Inc.,
1451 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
15**********/
16// "liveMedia"
17// Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved.
18// A simple UDP source, where every UDP payload is a complete frame
19// Implementation
20
21#include "BasicUDPSource.hh"
22#include <GroupsockHelper.hh>
23
24BasicUDPSource* BasicUDPSource::createNew(UsageEnvironment& env,
25 Groupsock* inputGS) {
26 return new BasicUDPSource(env, inputGS);
27}
28
29BasicUDPSource::BasicUDPSource(UsageEnvironment& env, Groupsock* inputGS)
30 : FramedSource(env), fInputGS(inputGS), fHaveStartedReading(False) {
31 // Try to use a large receive buffer (in the OS):
32 increaseReceiveBufferTo(env, inputGS->socketNum(), 50*1024);
33
34 // Make the socket non-blocking, even though it will be read from only asynchronously, when packets arrive.
35 // The reason for this is that, in some OSs, reads on a blocking socket can (allegedly) sometimes block,
36 // even if the socket was previously reported (e.g., by "select()") as having data available.
37 // (This can supposedly happen if the UDP checksum fails, for example.)
38 makeSocketNonBlocking(fInputGS->socketNum());
39}
40
41BasicUDPSource::~BasicUDPSource(){
42 envir().taskScheduler().turnOffBackgroundReadHandling(fInputGS->socketNum());
43}
44
45void BasicUDPSource::doGetNextFrame() {
46 if (!fHaveStartedReading) {
47 // Await incoming packets:
48 envir().taskScheduler().turnOnBackgroundReadHandling(fInputGS->socketNum(),
49 (TaskScheduler::BackgroundHandlerProc*)&incomingPacketHandler, this);
50 fHaveStartedReading = True;
51 }
52}
53
54void BasicUDPSource::doStopGettingFrames() {
55 envir().taskScheduler().turnOffBackgroundReadHandling(fInputGS->socketNum());
56 fHaveStartedReading = False;
57}
58
59
60void BasicUDPSource::incomingPacketHandler(BasicUDPSource* source, int /*mask*/){
61 source->incomingPacketHandler1();
62}
63
64void BasicUDPSource::incomingPacketHandler1() {
65 if (!isCurrentlyAwaitingData()) return; // we're not ready for the data yet
66
67 // Read the packet into our desired destination:
68 struct sockaddr_in fromAddress;
69 if (!fInputGS->handleRead(fTo, fMaxSize, fFrameSize, fromAddress)) return;
70
71 // Tell our client that we have new data:
72 afterGetting(this); // we're preceded by a net read; no infinite recursion
73}
74