From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Horman Subject: Re: [PATCH net-next v10 2/5] openvswitch: set skb protocol and mac_len when receiving on internal device Date: Fri, 17 Jun 2016 14:53:34 +0900 Message-ID: <20160617055331.GA24833@vergenet.net> References: <1464848686-7656-1-git-send-email-simon.horman@netronome.com> <1464848686-7656-3-git-send-email-simon.horman@netronome.com> <20160607030809.GE31696@vergenet.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux Kernel Network Developers , ovs dev To: pravin shelar Return-path: Received: from mail-pf0-f177.google.com ([209.85.192.177]:35924 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752172AbcFQFxn (ORCPT ); Fri, 17 Jun 2016 01:53:43 -0400 Received: by mail-pf0-f177.google.com with SMTP id t190so27410968pfb.3 for ; Thu, 16 Jun 2016 22:53:43 -0700 (PDT) Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Jun 07, 2016 at 03:45:27PM -0700, pravin shelar wrote: > On Mon, Jun 6, 2016 at 8:08 PM, Simon Horman wrote: > > On Thu, Jun 02, 2016 at 03:01:47PM -0700, pravin shelar wrote: > >> On Wed, Jun 1, 2016 at 11:24 PM, Simon Horman > >> wrote: > >> > * Set skb protocol based on contents of packet. I have observed this is > >> > necessary to get actual protocol of a packet when it is injected into an > >> > internal device e.g. by libnet in which case skb protocol will be set to > >> > ETH_ALL. > >> > > >> > * Set the mac_len which has been observed to not be set up correctly when > >> > an ARP packet is generated and sent via an openvswitch bridge. > >> > My test case is a scenario where there are two open vswtich bridges. > >> > One outputs to a tunnel port which egresses on the other. > >> > > >> > The motivation for this is that support for outputting to layer 3 (non-tap) > >> > GRE tunnels as implemented by a subsequent patch depends on protocol and > >> > mac_len being set correctly on receive. > >> > > >> > Signed-off-by: Simon Horman > >> > > >> > --- > >> > v10 > >> > * Set mac_len > >> > > >> > v9 > >> > * New patch > >> > --- > >> > net/openvswitch/vport-internal_dev.c | 4 ++++ > >> > 1 file changed, 4 insertions(+) > >> > > >> > diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c > >> > index 2ee48e447b72..f89b1efa88f1 100644 > >> > --- a/net/openvswitch/vport-internal_dev.c > >> > +++ b/net/openvswitch/vport-internal_dev.c > >> > @@ -48,6 +48,10 @@ static int internal_dev_xmit(struct sk_buff *skb, struct net_device *netdev) > >> > { > >> > int len, err; > >> > > >> > + skb->protocol = eth_type_trans(skb, netdev); > >> > + skb_push(skb, ETH_HLEN); > >> > + skb_reset_mac_len(skb); > >> > + > >> resetting mac-len breaks the assumption about mac_len for referencing > >> MPLS header ref: skb_mpls_header(). > > > > Thanks I had overlooked this. I think it is actually safe as > > the mac_len is recalculated quite soon in key_extract() and IIRC > > the most important thing is for mac_len to be 0 or non-zero > > for the benefit of ovs_flow_key_extract(). None the less it does > > seem untidy and moreover inconsistent with the handling in > > netdev_port_receive() by a latter patch which does the following: > > > > eth_type = eth_type_trans(skb, skb->dev); > > skb->mac_len = skb->data - skb_mac_header(skb); > > __skb_push(skb, skb->mac_len); > > > > if (eth_type == htons(ETH_P_8021Q)) > > skb->mac_len += VLAN_HLEN; > > > > Perhaps that logic ought to be in a helper used by both internal_dev_xmit() > > and netdev_port_receive(). Or somehow centralised in ovs_vport_receive(). > > This does looks bit complex. Can we use other skb metadata like > skb_mac_header_was_set()? Yes, I think that can be made to work if skb->mac_header is unset for l3 packets in netdev_port_receive(). The following is an incremental patch on the entire series. Is this the kind of thing you had in mind? diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c index 86f2cfb19de3..42587d5bf894 100644 --- a/net/openvswitch/flow.c +++ b/net/openvswitch/flow.c @@ -729,7 +729,7 @@ int ovs_flow_key_extract(const struct ip_tunnel_info *tun_info, key->phy.skb_mark = skb->mark; ovs_ct_fill_key(skb, key); key->ovs_flow_hash = 0; - key->phy.is_layer3 = skb->mac_len == 0; + key->phy.is_layer3 = skb_mac_header_was_set(skb) == 0; key->recirc_id = 0; err = key_extract(skb, key); diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c index 484ba529c682..8973d4db509b 100644 --- a/net/openvswitch/vport-internal_dev.c +++ b/net/openvswitch/vport-internal_dev.c @@ -50,7 +50,6 @@ static int internal_dev_xmit(struct sk_buff *skb, struct net_device *netdev) skb->protocol = eth_type_trans(skb, netdev); skb_push(skb, ETH_HLEN); - skb_reset_mac_len(skb); len = skb->len; rcu_read_lock(); diff --git a/net/openvswitch/vport-netdev.c b/net/openvswitch/vport-netdev.c index 3df36df62ee9..4cf3f12ffc99 100644 --- a/net/openvswitch/vport-netdev.c +++ b/net/openvswitch/vport-netdev.c @@ -60,22 +60,9 @@ static void netdev_port_receive(struct sk_buff *skb) if (vport->dev->type == ARPHRD_ETHER) { skb_push(skb, ETH_HLEN); skb_postpush_rcsum(skb, skb->data, ETH_HLEN); - } else if (vport->dev->type == ARPHRD_NONE) { - if (skb->protocol == htons(ETH_P_TEB)) { - __be16 eth_type; - - if (unlikely(skb->len < ETH_HLEN)) - goto error; - - eth_type = eth_type_trans(skb, skb->dev); - skb->mac_len = skb->data - skb_mac_header(skb); - __skb_push(skb, skb->mac_len); - - if (eth_type == htons(ETH_P_8021Q)) - skb->mac_len += VLAN_HLEN; - } else { - skb->mac_len = 0; - } + } else if (vport->dev->type == ARPHRD_NONE && + skb->protocol != htons(ETH_P_TEB)) { + skb->mac_header = (typeof(skb->mac_header))~0U; } ovs_vport_receive(vport, skb, skb_tunnel_info(skb));