Date: Thu, 19 Apr 2007 11:35:25 +0400 From: Yar Tikhiy <yar@comp.chem.msu.su> To: Alan Garfield <alan@fromorbit.com> Cc: freebsd-net@freebsd.org Subject: Re: rtentry and rtrequest Message-ID: <20070419073525.GA60301@comp.chem.msu.su> In-Reply-To: <1176947814.4175.39.camel@hiro.auspc.com.au> References: <1176861009.4426.21.camel@hiro.auspc.com.au> <20070418120622.GF40826@comp.chem.msu.su> <1176947814.4175.39.camel@hiro.auspc.com.au>
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On Thu, Apr 19, 2007 at 11:56:54AM +1000, Alan Garfield wrote:
> On Wed, 2007-04-18 at 16:06 +0400, Yar Tikhiy wrote:
> >
> > > I just want an idea of the structures involved, and what I need to
> > > implement to intercept and injecting a fake MAC so my buffer driver can
> > > communicate with the other side without ARP errors.
> >
> > Could you tell more details on the problem you are trying to solve
> > now. Sorry, but I fail to see what errors you get, and why. Doesn't
> > the Service Processor on the other side of that little Ethernet
> > link behave as a conventional IP host?
>
> Well it sort of does and it sort of doesn't unfortunately. It's MAC
> addresses are faked in the driver on both sides, and any ARP requests
> are caught and a fake response is generated. It's a wee bit ugly.
I wonder if this hack can be avoided... The other side could
just respond to our ARP requests.
> >From the GPL Linux driver
> ----
>
> int jnet_tx(struct sk_buff *skb, struct net_device *dev)
> {
>
> [...]
>
> if(htons(eth->h_proto) == ETH_P_ARP &&
> arp->ar_op == ARPOP_REQUEST) {
> //send fake response.
> jnet_arpResponse(dev);
> netif_wake_queue(jnet_devs);
> priv->fifoFull = FALSE;
> dev_kfree_skb(skb); // Free the SKB for arps too.
> } else {
> //so send the data
>
> [...]
> }
> }
>
> ----
>
> void jnet_arpResponse( struct net_device *dev )
> {
>
> [...]
>
> //Fill in all the blanks.
> memcpy(ðArp.eth.h_dest, localMac, sizeof(localMac));
> memcpy(ðArp.eth.h_source, remoteMac, sizeof(remoteMac));
> ethArp.eth.h_proto = ETH_P_ARP;
>
> ethArp.arp.ar_hrd = htons(ARPHRD_ETHER);
> ethArp.arp.ar_pro = htons(ETH_P_IP);
> ethArp.arp.ar_hln = sizeof(localMac);
> ethArp.arp.ar_pln = sizeof(uint32_t);
> ethArp.arp.ar_op = htons(ARPOP_REPLY);
>
> memcpy(ðArp.ar_sha, remoteMac, sizeof(remoteMac));
> memcpy(ðArp.ar_sip, &priv->myConfigIpSettings.platIp,
> sizeof(uint32_t));
>
> memcpy(ðArp.ar_tha, localMac, sizeof(localMac));
> memcpy(ðArp.ar_tip, &priv->myConfigIpSettings.spIp,
> sizeof(uint32_t));
>
> [...]
>
> }
>
> ----
>
> The problem I'm really seeing is I'm getting no mbuf's in my
> jnet_start(). It always returns zero.
>
> ----
>
> static void
> jnet_start_locked(struct ifnet* ifp)
> {
> // {{{
> struct jnet_softc *sc = ifp->if_softc;
>
> struct mbuf *m0, *m;
>
> device_printf(sc->dev, "jnet_start_locked() called.\n");
>
> JNET_ASSERT_LOCKED(sc);
>
> outputloop:
>
> // Check if there are buffered packets and an we're idle which
> // shouldn't happen at this point
> if (sc->txb_inuse && (sc->tx_busy == 0)) {
> device_printf(sc->dev, "packets buffered, but tx
> idle.\n");
> jnet_tx(sc);
> }
>
> // Check if there is room to put another packet in the buffer.
> if (sc->txb_inuse == sc->txb_cnt) {
>
> device_printf(sc->dev, "No room left in tx buffer.\n");
>
> // No room left. Set OACTIVE to tell everyone
> ifp->if_drv_flags |= IFF_DRV_OACTIVE;
> return;
> }
>
> IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
>
> if (m == 0) {
>
> device_printf(sc->dev, "m == 0.\n");
>
> // If buffers aren't filled we can still accept
> // more packets. So reset OACTIVE
> ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
> return;
> }
>
> // Copy mbuf to PRS
> m0 = m;
>
> //set address counter to zero, then read the entire fifo
> //bus_space_write_1(sc->iot[JNET_IOREGS], sc->ioh[JNET_IOREGS],
> JNET_STS_OFFSET, 0x00);
>
>
> device_printf(sc->dev, "mbuf len: %i.\n", m0->m_len);
>
> // Output to PRS buffer
> [...]
>
> sc->txb_inuse++;
>
> m_freem(m0);
>
> // Loop to top to possibly buffer more packets
> goto outputloop;
>
>
> // }}}
> }
>
> ----
>
> ... and I get these ARP errors.
>
> ----
> jnet0: <JNet Ethernet System Interface> port 0xa8,0xae-0xaf irq 19 on
> acpi0
> jnet0: Ethernet address: 00:09:3d:00:00:03
> jnet0: jnet_start_locked() called.
> jnet0: m == 0.
> jnet0: RTM_ADD.
> arplookup 169.254.101.2 failed: could not allocate llinfo
> arpresolve: can't allocate route for 169.254.101.2
> ----
>
> ... whenever I try and send anything.
Did you set the maximum lengths for the output queue and the driver
queue in the attach function?
--
Yar
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