Merge branch 'ipv6-Add-support-for-non-equal-cost-multipath'

Ido Schimmel says:

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ipv6: Add support for non-equal-cost multipath

This set aims to add support for IPv6 non-equal-cost multipath routes.
The first three patches convert multipath selection to use the
hash-threshold method (RFC 2992) instead of modulo-N. The same method is
employed by the IPv4 routing code since commit 0e884c78ee19 ("ipv4: L3
hash-based multipath").

Unlike modulo-N, with hash-threshold only the flows near the region
boundaries are affected when a nexthop is added or removed. In addition,
it allows us to easily add support for non-equal-cost multipath in the
last patch by sizing the different regions according to the provided
weights.
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Signed-off-by: David S. Miller <davem@davemloft.net>