Re: Help on sending a UDP Packet

Gary,

Here's a tcpdump in my case of the UDP test on port 13 between two different systems 
(192.168.0.1 and 192.168.0.2) :

# tcpdump -i net1 -nn -n -A port 13
dropped privs to nobody
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on net1, link-type EN10MB (Ethernet), capture size 262144 bytes
20:15:17.760479 IP 192.168.0.1.49167 > 192.168.0.2.13: UDP, length 11
E..'.W.....................xhello world
20:15:17.767964 IP 192.168.0.2.13 > 192.168.0.1.49167: UDP, length 26
E..6....<..b............."..Tue Jan 12 20:15:16 2021

^C
2 packets captured

The host 192.168.0.1 is running GNU smalltalk.
The host 192.168.0.2 is the one running the datagram daytime service.

Regards,
David Stes

----- Op 12 jan 2021 om 17:28 schreef Gary Highberger [email protected]:

> Hi David and everybody,
> 
> I just sent my first UDP packet with Smalltalk Sockets. It's likely just me
> but there might be some instability in gst. Somehow my Datagram Socket got
> wiped out. I'm going to run tests and publish my findings here.
> 
> Have GNU Smalltalk Sockets and the VM been proven in real world
> applications?
> 
> Packet:
> $ sudo tcpdump -i 1 -nn -n -A port 49152
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on wlp3s0, link-type EN10MB (Ethernet), capture size 262144 bytes
> 10:53:15.131345 IP 192.168.1.114.49153 > 192.168.1.249.49152: UDP, length 27
> E..7..@[email protected].........#..  Hi sailor! New in town?
> 
> Smalltalk:
> st> PackageLoader fileInPackage: 'Sockets'
> "Global garbage collection... done"
> Loading package Sockets
> PackageLoader
> st> DgS := Sockets.DatagramSocket remote: '192.168.1.249' port: 49152
> local: '192.168.1.114' port: 49153
> Sockets.DatagramSocket[192.168.1.114:49153]
> st> DgD := Sockets.Datagram data: '  Hi sailor! New in town?  '
> a Datagram
> st> DgS nextPut: DgD
> Sockets.DatagramSocket[192.168.1.114:49153]
> Voila
> 
> Many thanks for the help everybody!
> 
> Gary
> 
> On Sun, Jan 10, 2021 at 1:49 PM Gary Highberger <[email protected]>
> wrote:
> 
>> Hello David and all,
>>
>> I have a few (noob) questions about the UDP example Smalltalk program.
>> More questions likely to follow as I come up to speed. Your patience is
>> much appreciated David and everybody.
>>
>> QUESTIONS:
>> •  Is "_" the preferred assignment operator? I've been seeing ":=" too. I
>> don't have a back arrow on my keyboard. I guess the PARC people used "_".
>>
>> •  Does statement 1)
>> assign the destination IP address? Note that for my application, the
>> source and destination addresses will be different.
>>
>> •  Does statement 3)
>> populate the (UDP) datagram socket with the message, port, and address?
>> Why a "#" symbol prefixing the message string, 'hello world'?
>>
>> •  Does statement 4)
>> create a listening socket?
>>
>> •  Does statement 5)
>> trigger the send?
>>
>> •  Does statement 6)
>> block until the UDP response?
>>
>> +---------------------------------------------------------+
>>
>> UDP Smalltalk (example) program:
>>
>> 1) h _ Sockets.SocketAddress createLoopbackHost.
>>
>> 2) s _ Sockets.DatagramSocket new.
>>
>> 3) d _ Sockets.Datagram data:#'hello world' address:h port:13.
>>
>> 4) answer _ Sockets.Datagram new.
>>
>> 5) s nextPut:d.
>>
>> 6) s receive:answer.
>>
>> 7) (answer data) asString printNl.
>>
>> 8) s close.
>>
>> Gary Highberger
>>
>>
>> On Sun, Jan 10, 2021, 8:48 AM Gary Highberger <[email protected]>
>> wrote:
>>
>>> Good morning David,
>>>
>>> I'm not familiar with 'daytime' but will come up to speed on it and get
>>> it and your use cases running and report my findings for everybody to see.
>>>
>>> Hopefully netTest.c explains what I'm trying to do with Smalltalk. It's
>>> very short and simple.
>>>
>>> https://www.dropbox.com/s/xc23wj6r5aqh153/netTest.c?dl=0
>>>
>>> I used my cell phone as the destination, my home WiFi as the network, and
>>> tcpdump to see the packet.
>>>
>>> Thank you David for the Smalltalk code fragments and introducing me to
>>> inetd and 'daytime'.
>>>
>>> Gary Highberger
>>>
>>>