Re: [lwip-users] UDP bind error due to address and port reuse

[Surya Chaitanya]

Hi,

There are 5 different applications running on 5 different port numbers 
respectively 
on the PC. That's why we are using 5 different ports on destination side. 
Moreover, 
the PC-side implementation is not in our control. It is being implemented by a 
different team and there are some headers above UDP to distinguish the packets.

We are using RAW_API to send the UDP packets. 

So now, as mentioned earlier, from the FPGA board, we are using one port 
number(say 
x) to send to 5 different port numbers(say a,b,c,d,e) on the PC. And we would 
like 
to receive UDP packets from (a,b,c,d,e) ports - all onto the port 'x' on the 
FPGA 
board. 

So to achieve this, can I do it on a single PCB and listen to all the ports 
a,b,c,d,e on a single port 'x' on the FPGA board or do I have to create 5 PCBs, 
each 
of them individually listening to a single port on the PC? Thank you.

Regards,
Surya

On Wed, 7 Dec 2016 09:45:48 +0000, Noam Weissman wrote
> Hi,
> 
> I do not understand the logic in your design. If you send data to one IP why 
> use 5 different ports ? Either send some header that differentiate the 5 
> messages and in one receive function filter them to different recipient ?
> 
> As for your question:
> First of all you listen on one single port, meaning you bind IP+port to one 
> PCB.
> 
> Secondly when you send data you use udp_sendto (RAW API) or similar if you 
> use 
> Netconn or Socket API
> 
> The udp_sendto  function accepts IP and port:
>       err_t udp_sendto(struct udp_pcb *pcb, struct pbuf *p,  ip_addr_t 
> *dst_ip,
>  u16_t dst_port)
> 
> As for reply UDP packets from remote you better add some data in the reply 
> that will give you the correlation with the data sent.
> 
> Hope that helped.
> 
> BR,
> Noam.
> 
> -----Original Message-----
> From: Surya Chaitanya [mailto:address@hidden 
> Sent: Wednesday, December 07, 2016 10:53 AM
> To: Mailing list for lwIP users
> Cc: Noam Weissman; address@hidden; address@hidden
> Subject: Re: [lwip-users] UDP bind error due to address and port reuse
> 
> Hi Noam,
> 
> Our situation is something like this:
> 
> We have a Xilinx FPGA board. From one source port on the board, we would like 
> to send 5 UDP request packets to 5 different destination port numbers on a 
> PC. 
> And, we would also like to receive 5 response packets, one from each of the 5 
> ports on the PC to the single port on the FPGA board. Please let us know how 
> to achieve this using the lwIP stack. Thank You.
> 
> Regards,
> Surya
> 
> On Sat, 3 Dec 2016 12:56:52 +0000, Noam Weissman wrote
> > Hi,
> > 
> > If I understand you correctly you are trying to bind IP:port several 
> > times on the same machine
> > 
> > without closing the previous bind ?
> > 
> > This is not an option. You can bind UDP and TCP separately with two 
> > different pcb's one for
> > 
> > TCP and one for UDP.
> > 
> > You cannot bind an IP:Port more then one time. This is the meaning of 
> > binding.
> > 
> > Its like a marriage between IP and a Port. Until you do not divorce 
> > you cannot marry again [UTF-8?][UTF-8?][😊]
> > 
> > BR,
> > 
> > Noam.
> > 
> > ________________________________
> > From: lwip-users <address@hidden> on 
> > behalf of Surya Chaitanya <address@hidden>
>  Sent: Saturday, December 3, 2016 10:44 AM
> 
> > To: address@hidden
>  Subject: [lwip-users] UDP bind error due to address 
> > and port reuse
> > 
> > Hi,
> > 
> > I've been trying to use lwip to transfer UDP packets. In my situation, 
> > in the client
>  application, I would like to create 5 UDP PCBs having the same IP 
> > address and port
>  number. Inspite of setting the SO_REUSE flag to 1, and 
> > setting the SOF_REUSEADDR flag
>  to 1 for all the PCBs, the UDP bind error 
> > still persists. Could somebody pls. help me
>  out? Thank You.
> > 
> > Disclaimer:
> > ----------
> > This email and any files transmitted with it are confidential and 
> > intended solely for
>  the use of the individual or entity to whom they are addressed.  
> > If you are not the
>  intended recipient you are notified that disclosing, 
> > copying, distributing or taking
>  any
>  action in reliance on the contents of 
> > this information is strictly prohibited. The
>  sender does not accept liability 
> > for any errors or omissions in the contents of this
>  message, which arise as a 
> > result of e-mail transmission.
> > 
> > --
> > Open WebMail Project (http://openwebmail.org) Open WebMail 
> > Project<http://openwebmail.org/> openwebmail.org INTRODUCTION. Open 
> > WebMail is a webmail system based on the Neomail version
> > 1.14 from Ernie Miller. Open WebMail is designed to manage very large 
> > mail folder ...
> > 
> > _______________________________________________
> > lwip-users mailing list
> > address@hidden
> > https://lists.nongnu.org/mailman/listinfo/lwip-users
> > lwip-users -- Mailing list for lwIP users -  
> > lists.nongnu.org<https://lists.nongnu.org/mailman/listinfo/lwip-users>
> 
> > lists.nongnu.org
>  Welcome to the lwip-users mailing list. Use it to ask 
> > questions, share your experience and discuss new ideas. To see the 
> > collection of prior postings to the list ...
> 
> Disclaimer:
> ----------
> This email and any files transmitted with it are confidential and intended 
> solely for the use of the individual or entity to whom they are addressed.  
> If you are not the intended recipient you are notified that disclosing,
>  copying, distributing or taking any action in reliance on the contents of 
> this information is strictly prohibited. The sender does not accept liability 
> for any errors or omissions in the contents of this message, which arise as a 
> result of e-mail transmission.
> 
> --
> Open WebMail Project (http://openwebmail.org)


Disclaimer:
----------
This email and any files transmitted with it are confidential and intended 
solely 
for 
the use of the individual or entity to whom they are addressed.  If you are 
not the 
intended recipient you are notified that disclosing, copying, distributing or 
taking 
any 
action in reliance on the contents of this information is strictly prohibited. 
The 
sender does not accept liability for any errors or omissions in the contents of 
this 
message, which arise as a result of e-mail transmission.

--
Open WebMail Project (http://openwebmail.org)