As reported by Lennert the MPLS GSO code is failing to properly segment
large packets. There are a couple of problems:
1. the inner protocol is not set so the gso segment functions for inner
protocol layers are not getting run, and
2 MPLS labels for packets that use the "native" (non-OVS) MPLS code
are not properly accounted for in mpls_gso_segment.
The MPLS GSO code was added for OVS. It is re-using skb_mac_gso_segment
to call the gso segment functions for the higher layer protocols. That
means skb_mac_gso_segment is called twice -- once with the network
protocol set to MPLS and again with the network protocol set to the
inner protocol.
This patch sets the inner skb protocol addressing item 1 above and sets
the network_header and inner_network_header to mark where the MPLS labels
start and end. The MPLS code in OVS is also updated to set the two
network markers.
>From there the MPLS GSO code uses the difference between the network
header and the inner network header to know the size of the MPLS header
that was pushed. It then pulls the MPLS header, resets the mac_len and
protocol for the inner protocol and then calls skb_mac_gso_segment
to segment the skb.
Afterward the inner protocol segmentation is done the skb protocol
is set to mpls for each segment and the network and mac headers
restored.
Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In several gso_segment functions there are checks of gso_type against
a seemingly arbitrary list of SKB_GSO_* flags. This seems like an
attempt to identify unsupported GSO types, but since the stack is
the one that set these GSO types in the first place this seems
unnecessary to do. If a combination isn't valid in the first
place that stack should not allow setting it.
This is a code simplication especially for add new GSO types.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds support for TSO using IPv4 headers with a fixed IP ID
field. This is meant to allow us to do a lossless GRO in the case of TCP
flows that use a fixed IP ID such as those that convert IPv6 header to IPv4
headers.
In addition I am adding a feature that for now I am referring to TSO with
IP ID mangling. Basically when this flag is enabled the device has the
option to either output the flow with incrementing IP IDs or with a fixed
IP ID regardless of what the original IP ID ordering was. This is useful
in cases where the DF bit is set and we do not care if the original IP ID
value is maintained.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When we scan a packet for GRO processing, we want to see the most
common packet types in the front of the offload_base list.
So add a priority field so we can handle this properly.
IPv4/IPv6 get the highest priority with the implicit zero priority
field.
Next comes ethernet with a priority of 10, and then we have the MPLS
types with a priority of 15.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
They are all either written once or extremly rarely (e.g. from init
code), so we can move them to the .data..read_mostly section.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
MPLS and Tunnel GSO does not work together. Reject packet which
request such GSO.
Fixes: 0d89d2035f ("MPLS: Add limited GSO support").
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Device can export MPLS GSO support in dev->mpls_features same way
it export vlan features in dev->vlan_features. So it is safe to
remove NETIF_F_GSO_MPLS redundant flag.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
mpls gso handler needs to pull skb after segmenting skb.
CC: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_gso_segment() has a 'features' argument representing offload features
available to the output path.
A few handlers, e.g. GRE, instead re-fetch the features of skb->dev and use
those instead of the provided ones when handing encapsulation/tunnels.
Depending on dev->hw_enc_features of the output device skb_gso_segment() can
then return NULL even when the caller has disabled all GSO feature bits,
as segmentation of inner header thinks device will take care of segmentation.
This e.g. affects the tbf scheduler, which will silently drop GRE-encap GSO skbs
that did not fit the remaining token quota as the segmentation does not work
when device supports corresponding hw offload capabilities.
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The send_check logic was only interesting in cases of TCP offload and
UDP UFO where the checksum needed to be initialized to the pseudo
header checksum. Now we've moved that logic into the related
gso_segment functions so gso_send_check is no longer needed.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Call gso_make_checksum. This should have the benefit of using a
checksum that may have been previously computed for the packet.
This also adds NETIF_F_GSO_GRE_CSUM to differentiate devices that
offload GRE GSO with and without the GRE checksum offloaed.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now inet_gso_segment() is stackable, its relatively easy to
implement GSO/TSO support for IPIP
Performance results, when segmentation is done after tunnel
device (as no NIC is yet enabled for TSO IPIP support) :
Before patch :
lpq83:~# ./netperf -H 7.7.9.84 -Cc
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
87380 16384 16384 10.00 3357.88 5.09 3.70 2.983 2.167
After patch :
lpq83:~# ./netperf -H 7.7.9.84 -Cc
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
87380 16384 16384 10.00 7710.19 4.52 6.62 1.152 1.687
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the case where a non-MPLS packet is received and an MPLS stack is
added it may well be the case that the original skb is GSO but the
NIC used for transmit does not support GSO of MPLS packets.
The aim of this code is to provide GSO in software for MPLS packets
whose skbs are GSO.
SKB Usage:
When an implementation adds an MPLS stack to a non-MPLS packet it should do
the following to skb metadata:
* Set skb->inner_protocol to the old non-MPLS ethertype of the packet.
skb->inner_protocol is added by this patch.
* Set skb->protocol to the new MPLS ethertype of the packet.
* Set skb->network_header to correspond to the
end of the L3 header, including the MPLS label stack.
I have posted a patch, "[PATCH v3.29] datapath: Add basic MPLS support to
kernel" which adds MPLS support to the kernel datapath of Open vSwtich.
That patch sets the above requirements in datapath/actions.c:push_mpls()
and was used to exercise this code. The datapath patch is against the Open
vSwtich tree but it is intended that it be added to the Open vSwtich code
present in the mainline Linux kernel at some point.
Features:
I believe that the approach that I have taken is at least partially
consistent with the handling of other protocols. Jesse, I understand that
you have some ideas here. I am more than happy to change my implementation.
This patch adds dev->mpls_features which may be used by devices
to advertise features supported for MPLS packets.
A new NETIF_F_MPLS_GSO feature is added for devices which support
hardware MPLS GSO offload. Currently no devices support this
and MPLS GSO always falls back to software.
Alternate Implementation:
One possible alternate implementation is to teach netif_skb_features()
and skb_network_protocol() about MPLS, in a similar way to their
understanding of VLANs. I believe this would avoid the need
for net/mpls/mpls_gso.c and in particular the calls to
__skb_push() and __skb_push() in mpls_gso_segment().
I have decided on the implementation in this patch as it should
not introduce any overhead in the case where mpls_gso is not compiled
into the kernel or inserted as a module.
MPLS GSO suggested by Jesse Gross.
Based in part on "v4 GRE: Add TCP segmentation offload for GRE"
by Pravin B Shelar.
Cc: Jesse Gross <jesse@nicira.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
