kernel network

[Ferner Cilloniz]

Thanks! That solved it.

On Tue, 2008-12-30 at 23:03 -0600, Gerry Weaver wrote:
>         
>         ______________________________________________________________
>         From: Ferner Cilloniz [mailto:fernercc at gmail.com]
>         To: freebsd-net at 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.
>         
>         static int my_udp_send(struct thread *td, void *syscall_args)
>         {
>         struct socket *sock = NULL;
>         
>         if( socreate(AF_INET, &sock, SOCK_DGRAM, 0,
>         td->td_proc->p_ucred,
>         td) != 0 ) {
>         uprintf("socreate() returned error\n");
>         return -1;
>         }
>         
>         struct sockaddr_in sin;
>         sin.sin_len = sizeof(struct sockaddr_in);
>         sin.sin_family = AF_INET;
>         sin.sin_port = htons(8080);
>         inet_aton("192.168.2.2", &sin.sin_addr);
>         
>         struct mbuf *top = m_getclr(M_TRYWAIT, MT_CONTROL);
>         
>         // IP is 0
>         int sosend_error = sosend(sock, (struct sockaddr *)&sin, NULL,
>         top,
>         NULL, 0, td);
>         uprintf("sosend(): %d\n", sosend_error);
>         
>         soclose(sock);
>         
>         return 0;
>         }
>         
>         
>         
>         
>         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:
>         > 
>         >
>         -------------------------------------------------------------------------
>         > static int my_udp_send(struct thread *td, void
>         *syscall_args)
>         > {
>         > struct socket *sock = NULL;
>         > 
>         > if( socreate(AF_INET, &sock, SOCK_DGRAM, 0,
>         td->td_proc->p_ucred,
>         > td) != 0 ) {
>         > uprintf("socreate() returned error\n");
>         > return -1;
>         > }
>         > 
>         > struct sockaddr sa;
>         > sa.sa_len = sizeof(struct sockaddr_in);
>         > 
>         > struct sockaddr_in *sin = (struct sockaddr_in *)&sa;
>         > sin->sin_family = AF_INET;
>         > inet_aton("192.168.2.2", (struct sockaddr_in
>         *)&sin->sin_addr);
>         > sin->sin_port = htons(8080);
>         > sin->sin_len = sizeof(*sin);
>         > memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
>         > 
>         > // int soconnect_error = soconnect(sock, (struct sockaddr
>         *)sin, td);
>         > // uprintf("soconnect(): %d\n", soconnect_error);
>         > 
>         > struct mbuf *top = m_getclr(M_TRYWAIT, MT_CONTROL);
>         > 
>         > // IP is 0
>         > int sosend_error = sosend(sock, (struct sockaddr *)sin,
>         NULL, top,
>         > NULL, 0, td);
>         > uprintf("sosend(): %d\n", sosend_error);
>         > 
>         > soclose(sock);
>         > 
>         > return 0;
>         > }
>         >
>         -------------------------------------------------------------------------
>         > 
>         > 
>         > 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.
>         > 
>         > Am i doing something wrong? Note, that I am not filling in
>         the mbuf and
>         > all the wacking casting done.
>         > 
>         > Thanks. 
>         > 
>         > On Tue, 2008-12-30 at 18:46 +0000, Robert Watson wrote:
>         > > On Tue, 30 Dec 2008, Max Laier wrote:
>         > > 
>         > > > 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 cannot seem 
>         > > >> to understand what to do. I have tried more about a
>         month now to send 
>         > > >> arbitrary UDP packets from a kernel module but cannot
>         achieve it. I have 
>         > > >> looked at udp_send but found that building a socket*
>         was much to tedious. 
>         > > >> Later i looked at in-kernel webservers
>         (http://openketa.sourceforge.net/) 
>         > > >> but could not find anything useful.
>         > > >>
>         > > >> Netgraph is a possibility, but there isn't any
>         documentation on accessing 
>         > > >> the network from kernel space.
>         > > >>
>         > > >> What do you all suggest?
>         > > >
>         > > > $ man 9 socket
>         > > 
>         > > Definitely the preferred solution, if it meets the
>         application model. Call 
>         > > socreate(9) to allocate the socket, sobind(9) if required,
>         calls to sosend(9) 
>         > > to generate packets, and soclose(9) when done. Direct
>         calls to the 
>         > > udp_output() and udp_send() functions won't work without a
>         socket context, and 
>         > > doing sosend(9) will isolate in-kernel consumers from
>         future changes in UDP 
>         > > internals. ip_output() could be invoked directly to
>         generate IP packets, but 
>         > > won't allow you to easily receive replies, etc.
>         > > 
>         > > Robert N M Watson
>         > > Computer Laboratory
>         > > University of Cambridge
>         -- 
>         Cilloniz Bicchi, Ferner
>         
>         Research Assistant
>         Dept. of Computer Sciences
>         The University of Texas at Austin
>         http://www.cs.utexas.edu/~fernercc
>         fernercc at cs.utexas.edu
>         
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> Hello Ferner,
> 
> I believe you need a packet header in your mbuf. Try m_gethdr instead
> of 
> m_getclr.
> 
> Thanks,
> Gerry
-- 
Cilloniz Bicchi, Ferner

Research Assistant
Dept. of Computer Sciences
The University of Texas at Austin
http://www.cs.utexas.edu/~fernercc
fernercc at cs.utexas.edu