From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [Xen-devel] [PATCH 6/6] xen-netback: don't disconnect frontend when seeing oversize frame Date: Mon, 25 Mar 2013 12:58:34 -0400 Message-ID: <20130325165834.GC25740@phenom.dumpdata.com> References: <1364209702-12437-1-git-send-email-wei.liu2@citrix.com> <1364209702-12437-7-git-send-email-wei.liu2@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: xen-devel@lists.xen.org, netdev@vger.kernel.org, annie.li@oracle.com, david.vrabel@citrix.com, ian.campbell@citrix.com To: Wei Liu Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:25664 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932231Ab3CYQ6q (ORCPT ); Mon, 25 Mar 2013 12:58:46 -0400 Content-Disposition: inline In-Reply-To: <1364209702-12437-7-git-send-email-wei.liu2@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Mar 25, 2013 at 11:08:22AM +0000, Wei Liu wrote: > Some buggy frontends may generate frames larger than 64 KiB. We should > aggresively consume all slots and drop the packet instead of disconnecting the > frontend. > > Signed-off-by: David Vrabel > Signed-off-by: Wei Liu CC stable@vger.kernel.org ? > --- > drivers/net/xen-netback/netback.c | 32 ++++++++++++++++++++++++++------ > 1 file changed, 26 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index a634dc5..1971623 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -924,10 +924,12 @@ static void netbk_fatal_tx_err(struct xenvif *vif) > static int netbk_count_requests(struct xenvif *vif, > struct xen_netif_tx_request *first, > struct xen_netif_tx_request *txp, > - int work_to_do) > + int work_to_do, > + RING_IDX first_idx) > { > RING_IDX cons = vif->tx.req_cons; > int slots = 0; > + bool drop = false; > > if (!(first->flags & XEN_NETTXF_more_data)) > return 0; > @@ -947,10 +949,21 @@ static int netbk_count_requests(struct xenvif *vif, > > memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), > sizeof(*txp)); > - if (txp->size > first->size) { > - netdev_err(vif->dev, "Packet is bigger than frame.\n"); > - netbk_fatal_tx_err(vif); > - return -EIO; > + > + /* If the guest submitted a frame >= 64 KiB then > + * first->size overflowed and following slots will > + * appear to be larger than the frame. > + * > + * This cannot be fatal error as there are buggy > + * frontends that do this. > + * > + * Consume all slots and drop the packet. > + */ > + if (!drop && txp->size > first->size) { > + if (net_ratelimit()) > + netdev_dbg(vif->dev, > + "Packet is bigger than frame.\n"); > + drop = true; > } > > first->size -= txp->size; > @@ -963,6 +976,12 @@ static int netbk_count_requests(struct xenvif *vif, > return -EINVAL; > } > } while ((txp++)->flags & XEN_NETTXF_more_data); > + > + if (drop) { > + netbk_tx_err(vif, first, first_idx + slots); > + return -EIO; > + } > + > return slots; > } > > @@ -1429,7 +1448,8 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) > continue; > } > > - ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do); > + ret = netbk_count_requests(vif, &txreq, txfrags, > + work_to_do, idx); > if (unlikely(ret < 0)) > continue; > > -- > 1.7.10.4 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel >