1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
function udpcrossping(servermode, hostname, port)
count = 0;
% Open udpsocket and bind udp port adress to it.
udp=pnet('udpsocket', port);
% Act as server or client?
if servermode
% Server waits for echo-requests and then responds with his system
% time:
% Use timeout to not block forever, makes it possible to update resized window.
while count < 1000
% Wait/Read udp packet to read buffer
len=pnet(udp,'readpacket');
if len>0,
% if packet larger then 1 byte then read maximum of 1 doubles in network byte order
data=pnet(udp,'read',1,'double');
%figure(fg);
% .... and plot doubles in axis.
%plot(data);
end
% Send reply:
pnet(udp,'write', GetSecs); % Write system time to write buffer
% [ip,rport]=pnet(udp, 'gethost');
pnet(udp,'writepacket', hostname, port); % Send buffer as UDP packet
% Increment count:
count = count + 1;
end
else
% Client sends request, waits for answer, times roundtrip:
localtime=zeros(1,1000);
remotetime=zeros(1,1000);
for i=1:1000
% Send local time:
pnet(udp,'write', GetSecs); % Write system time to write buffer
tpresend=GetSecs;
pnet(udp,'writepacket', hostname, port); % Send buffer as UDP packet
tpostsend=GetSecs;
tsent = (tpresend + tpostsend)/2;
% Wait for response:
len=pnet(udp,'readpacket');
tpostreceive = GetSecs;
roundtriptime = tpostreceive - tsent;
if len>0,
% if packet larger then 1 byte then read maximum of 1 doubles in network byte order
remotetimesample=pnet(udp,'read',1,'double');
%figure(fg);
% .... and plot doubles in axis.
%plot(data);
end
localtime(i)=tsent + 0.5 * roundtriptime;
remotetime(i)=remotetimesample;
end
end
% Close udp connection.
pnet(udp,'close');
if ~servermode
% Absolute values:
plot(localtime, remotetime);
% Realtive values:
figure;
baseline = min(localtime, remotetime);
plot(localtime - baseline, remotetime - baseline);
end
% End.
return;
|
