[PATCH net-next 0/3] ip: improve tcp sock multipath routing

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

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

Improve layer 4 multipath hash policy for local tcp connections:

patch 1: Select a source address that matches the nexthop device.
         Due to tcp_v4_connect making separate route lookups for saddr
         and route, the two can currently be inconsistent.

patch 2: Use all paths when opening multiple local tcp connections to
         the same ip address and port.

patch 3: Test the behavior of patch 2. Extend the fib_nexthops.sh
         testsuite with one opening many connections, and count SYNs
         on both egress devices.

Willem de Bruijn (3):
  ipv4: prefer multipath nexthop that matches source address
  ip: load balance tcp connections to single dst addr and port
  selftests/net: test tcp connection load balancing

 include/net/flow.h                          |  1 +
 include/net/ip_fib.h                        |  3 +-
 include/net/route.h                         |  3 +
 net/ipv4/fib_semantics.c                    | 39 ++++++----
 net/ipv4/route.c                            | 15 +++-
 net/ipv6/route.c                            | 13 +++-
 net/ipv6/tcp_ipv6.c                         |  2 +
 tools/testing/selftests/net/fib_nexthops.sh | 83 +++++++++++++++++++++
 8 files changed, 137 insertions(+), 22 deletions(-)

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2.49.0.805.g082f7c87e0-goog