From 363887a2cdfeb6af52a9b78d84697662adf6f8d5 Mon Sep 17 00:00:00 2001
From: Stephen Suryaputra <ssuryaextr@gmail.com>
Date: Thu, 13 Jun 2019 14:38:58 -0400
Subject: [PATCH] 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: Stephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
Documentation/networking/ip-sysctl.txt | 1 +
net/ipv4/route.c | 17 +++++++++++++++++
net/ipv4/sysctl_net_ipv4.c | 2 +-
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index f4b1043e92edc..dc473354d90b1 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -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
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 0700a7d598118..66cbe8a7a168b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -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);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 90f09e47198bf..0edfa810f9b97 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -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
{
--
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