Date: Mon, 8 Dec 1997 09:54:53 -0500 (EST) From: Feiyi Wang <fwang2@unity.ncsu.edu> To: Ruslan Ermilov <ru@ucb.crimea.ua> Cc: hackers@FreeBSD.ORG Subject: Re: help: divert sockets question Message-ID: <Pine.SOL.3.96.971208095136.16834B-100000@loki.csc.ncsu.edu> In-Reply-To: <199712081231.OAA07525@relay.ucb.crimea.ua>
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Hi,
It will work. Here is the way I did it
-- snip --
/* this is readIncoming() */
inbytes = recvfrom( fd,
inPacketBuf,
sizeof inPacketBuf,
0,
(struct sockaddr*) &inPacketAddr,
&addrsize);
/* this is writeIncoming() */
writeIncoming(int fd)
{
int wrote;
wrote = sendto( fd,
inPacketBuf,
inPacketLen,
0,
(struct sockaddr *) &inPacketAddr,
sizeof inPacketAddr);
if ( wrote != inPacketLen )
fprintf(stderr, "failed to write packet back\n");
else
return wrote;
}
On Mon, 8 Dec 1997, Ruslan Ermilov wrote:
> Hi, Hackers!
>
> I'm in process of writing a small `iptunnel' program
> which lets me tunnel IP traffic thru UDP.
>
> My program uses two sockets: UDP and divert.
>
> It reads IP-packet from divert socket and
> sends it to the remote machine thru UDP.
> Remote machine then reads it from UDP and
> reinjects the IP-packet by writing it to the
> divert socket.
>
> And vice versa.
>
> It works greatly!
>
> Problem:
>
> I want to reinject received thru UDP IP-packet
> as incoming. `man ipdivert' says that I should
> use sendto() syscall with a destination address
> equal to IP address of some my local interface.
>
> I did it and it doesn't works.
>
> It seems to me like a kernel is just dropping such a packet.
> But no error returned from sendto(), no packets travel
> thru the firewall.
>
> Can anyone point me a way to write packet as incoming?
> Should I change some IP-packet fields?
>
> TIA,
> --
> Ruslan A. Ermilov System Administrator
> ru@ucb.crimea.ua United Commercial Bank
> +380-652-247647 Simferopol, Crimea
> 2426679 ICQ Network, UIN
>
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