[PATCH net-next RFC 0/8] udp and configurable gro

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

From: Willem de Bruijn <willemb@google.com>

This is a *very rough* draft. Mainly for discussion while we also
look at another partially overlapping approach [1].

Reduce UDP receive cost for bulk traffic by enabling datagram
coalescing with GRO.

Before adding more GRO callbacks, make GRO configurable by the
administrator to optionally reduce the attack surface of this
early receive path. See also [2].

Introduce sysctls net.(core|ipv4|ipv6).gro that expose the table of
protocols for which GRO is support. Allow the administrator to disable
individual entries in the table.

To have a single infrastructure, convert dev_offloads to the
table-based approach to existing inet(6)_offloads. Additional small
benefit is that ipv6 will no longer take two list lookups to find.

Patch 1 converts dev_offloads to the infra of inet(6)_offloads
Patch 2 deduplicates gro_complete logic now that all share infra
Patch 3 does the same for gro_receive, in anticipation of adding
        a branch to check whether gro_receive is enabled
Patch 4 harmonizes ipv6 header opts, so that those, too can be
        optionally disabled.
Patch 5 makes inet(6)_offloads non-const to allow disabling a flag
Patch 6 introduces the administrative sysctl
Patch 7 avoids udp gro cost if no udp gro callback is register
Patch 8 introduces udp gro

[1] http://patchwork.ozlabs.org/project/netdev/list/?series=65741
[2] http://vger.kernel.org/netconf2017_files/rx_hardening_and_udp_gso.pdf

Willem de Bruijn (8):
  gro: convert device offloads to net_offload
  gro: deduplicate gro_complete
  gro: add net_gro_receive
  ipv6: remove offload exception for hopopts
  net: deconstify net_offload
  net: make gro configurable
  udp: gro behind static key
  udp: add gro

 drivers/net/geneve.c       |  11 +---
 drivers/net/vxlan.c        |   8 +++
 include/linux/netdevice.h  |  64 +++++++++++++++++++--
 include/net/protocol.h     |  19 ++-----
 include/net/udp.h          |   2 +
 include/uapi/linux/udp.h   |   1 +
 net/8021q/vlan.c           |  12 +---
 net/core/dev.c             | 112 ++++++++-----------------------------
 net/core/sysctl_net_core.c |  60 ++++++++++++++++++++
 net/ethernet/eth.c         |  13 +----
 net/ipv4/af_inet.c         |  21 ++-----
 net/ipv4/esp4_offload.c    |   2 +-
 net/ipv4/fou.c             |  41 ++++----------
 net/ipv4/gre_offload.c     |  26 ++++-----
 net/ipv4/protocol.c        |  10 ++--
 net/ipv4/sysctl_net_ipv4.c |   7 +++
 net/ipv4/tcp_offload.c     |   2 +-
 net/ipv4/udp.c             |  73 +++++++++++++++++++++++-
 net/ipv4/udp_offload.c     |  19 +++----
 net/ipv6/esp6_offload.c    |   2 +-
 net/ipv6/exthdrs_offload.c |  17 +++++-
 net/ipv6/ip6_offload.c     |  69 +++++++++--------------
 net/ipv6/protocol.c        |  10 ++--
 net/ipv6/sysctl_net_ipv6.c |   8 +++
 net/ipv6/tcpv6_offload.c   |   2 +-
 net/ipv6/udp.c             |   2 +-
 net/ipv6/udp_offload.c     |   4 +-
 net/sctp/offload.c         |   2 +-
 28 files changed, 344 insertions(+), 275 deletions(-)

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2.19.0.397.gdd90340f6a-goog