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Old 12-30-2004, 12:53 PM   #1
brianvdc
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Registered: Feb 2003
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Socket programming question


All,

I am trying to receive a UDP packet from a socket and determine the IP address it came from. Is this possible?

I am currently able to receive the packet using a bind to any IP address with a specific port.

However, the recv call only returns the number of bytes read with no information about the incoming packet (other than the actual data).

Thanks in advance.

Brian
 
Old 12-30-2004, 01:06 PM   #2
deiussum
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For UDP packets, you should be using recvfrom instead of recv. That will get you an address that you are receiving from.
 
Old 12-30-2004, 01:36 PM   #3
Nerox
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Yes, it's possible to determine the IP address it came from. The IP address is stored in a sockaddr_in struct type whose address you have supplied to recvfrom as a pointer. The IP is in its sin_addr field.
The following code will print the foreign IP address:
Code:
printf("%s", inet_ntoa(client.sin_addr)); /* which client is your sockaddr_in struct */
I hope it helps

Last edited by Nerox; 12-30-2004 at 01:37 PM.
 
  


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