[PATCH net-next v3 0/1] Add support of ECMPv6

[Nicolas Dichtel <nicolas.dichtel@6wind.com>]

Here is a proposal to add the support of ECMPv6. The previous patch
from Vincent against iproute2 can be used, but a little other patch is needed
too, see http://patchwork.ozlabs.org/patch/183277/

If the kernel patch is approved, I can submit formally the patch for
iproute2.

Here is an example of a command to add an ECMP route:
$ ip -6 route add 3ffe:304:124:2306::/64 \
	nexthop via fe80::230:1bff:feb4:e05c dev eth0 \
	nexthop via fe80::230:1bff:feb4:dd4f dev eth0

But note that this command is a shortcut and previous patches are not
mandatory to set ECMP routes. The following commands can be used too:
$ ip -6 route add 3ffe:304:124:2306::/64 via fe80::230:1bff:feb4:dd4f dev
eth0
$ ip -6 route append 3ffe:304:124:2306::/64 via fe80::230:1bff:feb4:e05c dev
eth0

Here is an example of a dump:
$ ip -6 route | grep 3ffe:304:124:2306::/64
3ffe:304:124:2306::/64 via fe80::230:1bff:feb4:dd4f dev eth0  metric 1024
3ffe:304:124:2306::/64 via fe80::230:1bff:feb4:e05c dev eth0  metric 1024

v2: rename CONFIG_IPV6_MULTIPATH_ROUTE to CONFIG_IPV6_MULTIPATH_HASH
    use flowlabel in the hash function
    add reference to RFC
    fix a small identation issue
    remove "If unsure, say N." from the help of CONFIG_IPV6_MULTIPATH

v3: rebase after updating net-next

Comments are welcome.

Regards,
Nicolas