[PATCH net-next v2 2/3] ipv6: Support multipath hashing on inner IP pkts

[Stephen Suryaputra]

Make the same support as commit 363887a2cdfe ("ipv4: Support multipath
hashing on inner IP pkts for GRE tunnel") for outer IPv6. The hashing
considers both IPv4 and IPv6 pkts when they are tunneled by IPv6 GRE.

Signed-off-by: Stephen Suryaputra <ssuryae...@gmail.com>
---
 Documentation/networking/ip-sysctl.txt |  1 +
 net/ipv6/route.c                       | 36 ++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/Documentation/networking/ip-sysctl.txt 
b/Documentation/networking/ip-sysctl.txt
index f0e6d1f53485..48c79e78817b 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1473,6 +1473,7 @@ fib_multipath_hash_policy - INTEGER
        Possible values:
        0 - Layer 3 (source and destination addresses plus flow label)
        1 - Layer 4 (standard 5-tuple)
+       2 - Layer 3 or inner Layer 3 if present
 
 anycast_src_echo_reply - BOOLEAN
        Controls the use of anycast addresses as source addresses for ICMPv6
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 39361f57351a..4d2e6b31a8d6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2370,6 +2370,42 @@ u32 rt6_multipath_hash(const struct net *net, const 
struct flowi6 *fl6,
                        hash_keys.basic.ip_proto = fl6->flowi6_proto;
                }
                break;
+       case 2:
+               memset(&hash_keys, 0, sizeof(hash_keys));
+               hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+               if (skb) {
+                       struct flow_keys keys;
+
+                       if (!flkeys) {
+                               skb_flow_dissect_flow_keys(skb, &keys, 0);
+                               flkeys = &keys;
+                       }
+
+                       /* Inner can be v4 or v6 */
+                       if (flkeys->control.addr_type == 
FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
+                               hash_keys.control.addr_type = 
FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+                               hash_keys.addrs.v4addrs.src = 
flkeys->addrs.v4addrs.src;
+                               hash_keys.addrs.v4addrs.dst = 
flkeys->addrs.v4addrs.dst;
+                       } else if (flkeys->control.addr_type == 
FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
+                               hash_keys.control.addr_type = 
FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+                               hash_keys.addrs.v6addrs.src = 
flkeys->addrs.v6addrs.src;
+                               hash_keys.addrs.v6addrs.dst = 
flkeys->addrs.v6addrs.dst;
+                               hash_keys.tags.flow_label = 
flkeys->tags.flow_label;
+                               hash_keys.basic.ip_proto = 
flkeys->basic.ip_proto;
+                       } else {
+                               /* Same as case 0 */
+                               hash_keys.control.addr_type = 
FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+                               ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
+                       }
+               } else {
+                       /* Same as case 0 */
+                       hash_keys.control.addr_type = 
FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+                       hash_keys.addrs.v6addrs.src = fl6->saddr;
+                       hash_keys.addrs.v6addrs.dst = fl6->daddr;
+                       hash_keys.tags.flow_label = (__force 
u32)flowi6_get_flowlabel(fl6);
+                       hash_keys.basic.ip_proto = fl6->flowi6_proto;
+               }
+               break;
        }
        mhash = flow_hash_from_keys(&hash_keys);
 
-- 
2.17.1