inet_ntop() not returning IP address

Hi,

I am trying to track an incoming request to a TCP/IP server, the reason is we are trying to figure out who is doing a port scan on the listening port we use so that we can identify the responsible party. I have researched the available API's and how to implement and come up with the above API, however when I get the data back from the API all I get is an IP address of 0.0.0.0?

There are plenty of non IBM i examples out there and looking through the IBM documentation the API should work in the same manner as other implementations, one of the caveats is that IBM suggests the use of a structure structaddr_storage for the collection which needs to be cast on the call to the API.

Here is a summary of the code that I am using, I have not added all of the code (there is a lot of other code running which is not relevant to this).

int listen_sd, accept_sd = 0; // socket ints
socklen_t addr_len; // address struct len
struct sockaddr_storage addr_in; // socket address structure

// set up the address in structure
memset(&addr_in, 0, sizeof(addr_in));
addr_len = sizeof(addr_in);

// we set up the socket in another program and pass in
// via spawn request
listen_sd = atoi(argv[1]);

// set up the accept, we pass in the address structure cast to correct type which should get filled in when the connection is made with the source IP address
accept_sd = accept(listen_sd,(struct sockaddr *)&addr_in, &addr_len);

// recv the data from the client, this is not relevant but this is where we notice the problem
rc = recv(accept_sd, recv_buf,_IP_BUF_SIZE, 0);

// extract the remote IP address using the inet_ntop API
inet_ntop(AF_INET,(struct sockaddr *)&addr_in._ss_align,ip_addr,16);
len = sprintf(msg_dta,"Recv address %.16s",ip_addr);

// we should see the IP address the connection request came from
// but all we see is 'Recv address 0.0.0.0'

Has anyone else used this API successfully? Can they see something glaringly obviously wrong?

Thanks in advance.

Chris...

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Chris Hird
Director at Shield Advanced Solutions Ltd.

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