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Date: Mon, 12 Jan 2004 16:21:19 +0100
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Thread-Topic: verrevpath in ip_input (need help)
Thread-Index: AcPZH7qOtNw31iWmT9+RPP1nzEuMfg==
From: =?iso-8859-1?Q?Sten_Daniel_S=F8rsdal?= <sten.daniel.sorsdal@wan.no>
To: <freebsd-net@freebsd.org>
Subject: verrevpath in ip_input (need help)
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Has anyone made a patch to add ipfw2's verrev functionality in ip_input =
(or similar place) ?
I've tried for a few days to write it myself but it keeps panicing on =
(among other things) deleting of default route (i suspect that i really =
ask the route for 0.0.0.0).
I plan to add an ifconfig flag when this basic one works so i can =
enable/disable this feature pr interface.

this compiles but bombs on "route delete default", i dont have a monitor =
on this box because no monitor is available atm, so i cant really see =
what happens.=20


compilation flags are: -O -pipe -funroll-loops -ffast-math =20
os version: FreeBSD devil.wan.no 4.9-RELEASE-p1 FreeBSD 4.9-RELEASE-p1 =
(...) i386
can anyone spot the bug?=20


static int      ip_verrevinterface =3D 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, verrevinterface, CTLFLAG_RW,
    &ip_verrevinterface, 0, "Verify packet reverse path");
...
void ip_input (struct mbuf *m)
{
struct route verrev_ro;
...

iphack:
...
right after "if (fr_checkp) {" clause
...=09
        if (ip_verrevinterface && m->m_pkthdr.rcvif !=3D NULL && =
((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) =3D=3D 0)) {

                struct sockaddr_in *verrev_dst;

                verrev_dst =3D (struct sockaddr_in =
*)&(verrev_ro.ro_dst);

                /* Check if we've cached the route from the previous =
call. */
                verrev_ro.ro_rt =3D NULL;

                bzero(verrev_dst, sizeof(*verrev_dst));
                verrev_dst->sin_family =3D AF_INET;
                verrev_dst->sin_len =3D sizeof(*verrev_dst);
                verrev_dst->sin_addr =3D ip->ip_src;
                rtalloc_ign(&verrev_ro, RTF_CLONING|RTF_PRCLONING);

                if ((verrev_ro.ro_rt =3D=3D NULL) || =
(verrev_ro.ro_rt->rt_ifp->if_index !=3D m->m_pkthdr.rcvif->if_index)) {
                        printf("ip_input: verrevpath expected %d but got =
%d\n",
                         m->m_pkthdr.rcvif->if_index, =
verrev_ro.ro_rt->rt_ifp->if_index );
                }
        }
...


// sten