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Commit 363887a2 authored by Stephen Suryaputra's avatar Stephen Suryaputra Committed by David S. Miller
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ipv4: Support multipath hashing on inner IP pkts for GRE tunnel 



Multipath hash policy value of 0 isn't distributing since the outer IP
dest and src aren't varied eventhough the inner ones are. Since the flow
is on the inner ones in the case of tunneled traffic, hashing on them is
desired.

This is done mainly for IP over GRE, hence only tested for that. But
anything else supported by flow dissection should work.

v2: Use skb_flow_dissect_flow_keys() directly so that other tunneling
    can be supported through flow dissection (per Nikolay Aleksandrov).
v3: Remove accidental inclusion of ports in the hash keys and clarify
    the documentation (Nikolay Alexandrov).
Signed-off-by: default avatarStephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 31c03aef

Documentation/networking/ip-sysctl.txt

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ fib_multipath_hash_policy - INTEGER 
	Possible values:

	0 - Layer 3

	1 - Layer 4

	2 - Layer 3 or inner Layer 3 if present



fib_sync_mem - UNSIGNED INTEGER

	Amount of dirty memory from fib entries that can be backlogged before

net/ipv4/route.c

+17 −0
Original line number Diff line number Diff line
@@ -1930,6 +1930,23 @@ int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 
			hash_keys.basic.ip_proto = fl4->flowi4_proto;

		}

		break;

	case 2:

		memset(&hash_keys, 0, sizeof(hash_keys));

		hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;

		/* skb is currently provided only when forwarding */

		if (skb) {

			struct flow_keys keys;



			skb_flow_dissect_flow_keys(skb, &keys, 0);



			hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;

			hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;

		} else {

			/* Same as case 0 */

			hash_keys.addrs.v4addrs.src = fl4->saddr;

			hash_keys.addrs.v4addrs.dst = fl4->daddr;

		}

		break;

	}

	mhash = flow_hash_from_keys(&hash_keys);

net/ipv4/sysctl_net_ipv4.c

+1 −1
Original line number Diff line number Diff line
@@ -1008,7 +1008,7 @@ static struct ctl_table ipv4_net_table[] = { 
		.mode		= 0644,

		.proc_handler	= proc_fib_multipath_hash_policy,

		.extra1		= &zero,

		.extra2		= &one,

		.extra2		= &two,

	},

#endif

	{