Date: Sun, 02 Nov 2014 11:10:20 +0800 From: Julian Elischer <julian@freebsd.org> To: Hooman Fazaeli <hoomanfazaeli@gmail.com>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: transparent udp proxy Message-ID: <5455A09C.6030808@freebsd.org> In-Reply-To: <5455853E.2030700@freebsd.org> References: <54535B82.405@gmail.com> <5455853E.2030700@freebsd.org>
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On 11/2/14, 9:13 AM, Julian Elischer wrote: > On 10/31/14, 5:50 PM, Hooman Fazaeli wrote: >> Hi, >> >> I my setup, I use a fwd rule to forward all udp traffic to my local >> proxy: >> >> ipfw add 10 fwd localhost,7000 udp from any to any recv em1 > just as a nit, I'd add "in" as well sometimes outgoing packets can > have a receive interface if they were routed. > >> >> The proxy needs to know the original destination address of >> forwarded datagrams, but >> there seems to be no way to obtain that address. > hmm that used to work.. >> >> Using recvmsg with IP_RECVDSTADDR does not help because it returns >> next-hop address >> instead of original destination. This is because udp_input() >> overwrites packet's destination >> with next-hop address before doing ip_savecontrol. > This behaviour may be new since IPFORWARD was added.. My memory is > that you could do this. >> >> It seems easy to change udp_input to pass the original dest. >> address to ip_savecontrol. >> Another soultion would be to implement IP_RECVDSTSOCKADDR option, >> which records the original >> destination address:port as a 'struct sockaddr_in[6]' in packet's >> control data. >> >> Comments/suggestions are welcome. apply the following patches to your kernel http://svnweb.freebsd.org/base/stable/9/sys/netinet/udp_usrreq.c?r1=225043&r2=225044&; and http://svnweb.freebsd.org/base/stable/9/sys/netinet/udp_usrreq.c?r1=243585&r2=243586&; >> >> > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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