Date: Tue, 30 Dec 2008 23:03:18 -0600 From: "Gerry Weaver" <gerryw@compvia.com> To: "Ferner Cilloniz" <fernercc@gmail.com>, freebsd-net@freebsd.org Subject: Re: kernel network Message-ID: <20081231050318.616ef838@mail01.compvia.com> In-Reply-To: 1230672967.4966.26.camel@mobiliare.Belkin
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=5F=5F=5F=5F=5F =20
From: Ferner Cilloniz [mailto:fernercc@gmail.com]
To: freebsd-net@freebsd.org
Sent: Tue, 30 Dec 2008 15:36:07 -0600
Subject: Re: kernel network
I tried another approach. The code is below. However, wireshark does not
pick up anything happening. I don't know what is going on.
=20
static int my=5Fudp=5Fsend(struct thread *td, void *syscall=5Fargs)
{
struct socket *sock =3D NULL;
=20
if( socreate(AF=5FINET, &sock, SOCK=5FDGRAM, 0, td->td=5Fproc->p=
=5Fucred,
td) !=3D 0 ) {
uprintf("socreate() returned error\n");
return -1;
}
=20
struct sockaddr=5Fin sin;
sin.sin=5Flen =3D sizeof(struct sockaddr=5Fin);
sin.sin=5Ffamily =3D AF=5FINET;
sin.sin=5Fport =3D htons(8080);
inet=5Faton("192.168.2.2", &sin.sin=5Faddr);
=20
struct mbuf *top =3D m=5Fgetclr(M=5FTRYWAIT, MT=5FCONTROL);
=20
// IP is 0
int sosend=5Ferror =3D sosend(sock, (struct sockaddr *)&sin, NULL,=
top,
NULL, 0, td);
uprintf("sosend(): %d\n", sosend=5Ferror);
=20
soclose(sock);
=20
return 0;
}
=20
=20
=20
=20
On Tue, 2008-12-30 at 17:16 +0000, Ferner Cilloniz wrote:
> I have been tackling this today. This is what i have so far:
>=20
> --------------------------------------------------------------------=
-----
> static int my=5Fudp=5Fsend(struct thread *td, void *syscall=5Fargs)
> {
> struct socket *sock =3D NULL;
>=20
> if( socreate(AF=5FINET, &sock, SOCK=5FDGRAM, 0, td->td=5Fproc->p=
=5Fucred,
> td) !=3D 0 ) {
> uprintf("socreate() returned error\n");
> return -1;
> }
>=20
> struct sockaddr sa;
> sa.sa=5Flen =3D sizeof(struct sockaddr=5Fin);
>=20
> struct sockaddr=5Fin *sin =3D (struct sockaddr=5Fin *)&sa;
> sin->sin=5Ffamily =3D AF=5FINET;
> inet=5Faton("192.168.2.2", (struct sockaddr=5Fin *)&sin->sin=5Fa=
ddr);
> sin->sin=5Fport =3D htons(8080);
> sin->sin=5Flen =3D sizeof(*sin);
> memset(sin->sin=5Fzero, 0, sizeof(sin->sin=5Fzero));
>=20
> // int soconnect=5Ferror =3D soconnect(sock, (struct sockaddr *)s=
in, td);
> // uprintf("soconnect(): %d\n", soconnect=5Ferror);
>=20
> struct mbuf *top =3D m=5Fgetclr(M=5FTRYWAIT, MT=5FCONTROL);
>=20
> // IP is 0
> int sosend=5Ferror =3D sosend(sock, (struct sockaddr *)sin, NULL=
, top,
> NULL, 0, td);
> uprintf("sosend(): %d\n", sosend=5Ferror);
>=20
> soclose(sock);
>=20
> return 0;
> }
> --------------------------------------------------------------------=
-----
>=20
>=20
> However, when listening to my home network using wireshark, I filter=
out
> everything but UDP packets with the 192.168.2.2 address on them. I'm
> afraid to say that there aren't any packets showing.
>=20
> Am i doing something wrong=3F Note, that I am not filling in the mbu=
f and
> all the wacking casting done.
>=20
> Thanks.=20
>=20
> On Tue, 2008-12-30 at 18:46 +0000, Robert Watson wrote:
> > On Tue, 30 Dec 2008, Max Laier wrote:
> >=20
> > > On Tuesday 30 December 2008 12:49:55 Ferner Cilloniz wrote:
> > >
> > >> I do not think I could ever be more tired of this topic but I c=
annot seem=20
> > >> to understand what to do. I have tried more about a month now t=
o send=20
> > >> arbitrary UDP packets from a kernel module but cannot achieve i=
t. I have=20
> > >> looked at udp=5Fsend but found that building a socket* was much=
to tedious.=20
> > >> Later i looked at in-kernel webservers (http://openketa.sourcef=
orge.net/)=20
> > >> but could not find anything useful.
> > >>
> > >> Netgraph is a possibility, but there isn't any documentation on=
accessing=20
> > >> the network from kernel space.
> > >>
> > >> What do you all suggest=3F
> > >
> > > $ man 9 socket
> >=20
> > Definitely the preferred solution, if it meets the application mod=
el. Call=20
> > socreate(9) to allocate the socket, sobind(9) if required, calls t=
o sosend(9)=20
> > to generate packets, and soclose(9) when done. Direct calls to th=
e=20
> > udp=5Foutput() and udp=5Fsend() functions won't work without a soc=
ket context, and=20
> > doing sosend(9) will isolate in-kernel consumers from future chang=
es in UDP=20
> > internals. ip=5Foutput() could be invoked directly to generate IP=
packets, but=20
> > won't allow you to easily receive replies, etc.
> >=20
> > Robert N M Watson
> > Computer Laboratory
> > University of Cambridge
--=20
Cilloniz Bicchi, Ferner
=20
Research Assistant
Dept. of Computer Sciences
The University of Texas at Austin
http://www.cs.utexas.edu/~fernercc
fernercc@cs.utexas.edu
=20
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=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F
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Hello Ferner,
I believe you need a packet header in your mbuf. Try m=5Fgethdr instead =
of=20
m=5Fgetclr.
Thanks,
Gerry
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