linux_dsm_epyc7002/net/core
Simon Horman 0d89d2035f MPLS: Add limited GSO support
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>
2013-05-27 22:50:59 -07:00
..
datagram.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-04-30 03:55:20 -04:00
dev_addr_lists.c net: add dev_uc_sync_multiple() and dev_mc_sync_multiple() api 2013-04-15 16:10:47 -04:00
dev_ioctl.c net: move ioctl functions into a separated file 2013-02-18 12:27:32 -05:00
dev.c MPLS: Add limited GSO support 2013-05-27 22:50:59 -07:00
drop_monitor.c drop_monitor: dont sleep in atomic context 2012-06-04 11:42:01 -04:00
dst.c net: add skb_dst_set_noref_force 2013-04-02 00:22:53 +02:00
ethtool.c MPLS: Add limited GSO support 2013-05-27 22:50:59 -07:00
fib_rules.c rtnetlink: Remove passing of attributes into rtnl_doit functions 2013-03-22 10:31:16 -04:00
filter.c filter: add ANC_PAY_OFFSET instruction for loading payload start offset 2013-03-20 13:15:45 -04:00
flow_dissector.c net: flow_dissector: add __skb_get_poff to get a start offset to payload 2013-03-20 13:15:45 -04:00
flow.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-04-01 13:36:50 -04:00
gen_estimator.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
gen_stats.c gen_stats: Stop using NLA_PUT*(). 2012-04-02 04:33:44 -04:00
iovec.c Hoist memcpy_fromiovec/memcpy_toiovec into lib/ 2013-05-20 10:24:22 +09:30
link_watch.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2012-10-02 13:38:27 -07:00
Makefile net: move procfs code to net/core/net-procfs.c 2013-02-19 00:51:10 -05:00
neighbour.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
net_namespace.c proc: Split the namespace stuff out into linux/proc_ns.h 2013-05-01 17:29:39 -04:00
net-procfs.c rps: selective flow shedding during softnet overflow 2013-05-20 13:48:04 -07:00
net-sysfs.c rps_dev_flow_table_release(): no need to delay vfree() 2013-05-06 11:06:51 -04:00
net-sysfs.h xps: Add CONFIG_XPS 2010-11-28 18:24:14 -08:00
net-traces.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netevent.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netpoll.c netpoll: inverted down_trylock() test 2013-05-06 11:06:52 -04:00
netprio_cgroup.c Revert "netprio_cgroup: make local table static" 2013-04-12 03:06:44 -04:00
pktgen.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
request_sock.c tcp: fix a panic on UP machines in reqsk_fastopen_remove 2013-01-14 18:10:05 -05:00
rtnetlink.c net: fix address check in rtnl_fdb_del 2013-04-25 04:14:08 -04:00
scm.c netprio_cgroup: remove task_struct parameter from sock_update_netprio() 2013-04-09 13:19:37 -04:00
secure_seq.c net: defer net_secret[] initialization 2013-04-29 15:14:02 -04:00
skbuff.c net: Loosen constraints for recalculating checksum in skb_segment() 2013-05-22 15:06:13 -07:00
sock_diag.c sock_diag: allow to dump bpf filters 2013-04-29 13:21:30 -04:00
sock.c ipv6: do not clear pinet6 field 2013-05-11 16:26:38 -07:00
stream.c net: Fix the condition passed to sk_wait_event() 2010-10-03 20:41:32 -07:00
sysctl_net_core.c rps: selective flow shedding during softnet overflow 2013-05-20 13:48:04 -07:00
timestamping.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
user_dma.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
utils.c net: core: let's use native isxdigit instead of custom 2013-03-27 12:48:32 -04:00