Re: [lwip-users] How to get the ip address of the remote host in a connection

[Jonathan Larmour]

Antonio de Angelis wrote:
> In data 25 agosto 2008 alle ore 22:57:43, Jonathan Larmour
> <address@hidden> ha scritto:
> 
>> Antonio de Angelis wrote:
>>> Hi all,
>>> I've built a simple server application for the Win32 port. But now I
>>> want to implement a simple mechanism to refuse incoming connections
>>> from certain ip addresses... how can I get the ip address of a remote
>>> host that has just connected to the server? Thanks
>>
>> Which API are you using? Sockets, netconn (also known as sequential
>> API) or raw?
> 
> raw api.

First of all, just to be clear, lwIP is not able to refuse incoming
connections with anything like a "connection refused" ICMP message. It's
deliberately simple in that respect, in line with its general ethos, so it
doesn't have packet filtering capabilities. What you can do easily instead
is simply close the connection immediately after it is established. So when
your accept function is called, you can check the remote IP then.

The remote IP is simply available inside the PCB, e.g. assuming struct
tcp_pcb *pcb :

pcb->ip->remote_ip

Less officially, you would probably not find it hard to hack in a callback
in tcp_listen_input in src/core/tcp_in.c.

Hope this helps,

Jifl
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