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authorIdo Schimmel <idosch@OSS.NVIDIA.COM>2021-05-17 21:15:19 +0300
committerDavid S. Miller <davem@davemloft.net>2021-05-18 23:27:32 +0300
commit4253b4986f98da4bfcb6a24d3fc6ff19f28e8420 (patch)
treef6d5d7afd5f9dcd7c529212609df275417aaf7f8 /net/ipv4/route.c
parentce5c9c20d364f156c885efed8c71fca2945db00f (diff)
downloadlinux-4253b4986f98da4bfcb6a24d3fc6ff19f28e8420.tar.xz
ipv4: Add custom multipath hash policy
Add a new multipath hash policy where the packet fields used for hash calculation are determined by user space via the fib_multipath_hash_fields sysctl that was introduced in the previous patch. The current set of available packet fields includes both outer and inner fields, which requires two invocations of the flow dissector. Avoid unnecessary dissection of the outer or inner flows by skipping dissection if none of the outer or inner fields are required. In accordance with the existing policies, when an skb is not available, packet fields are extracted from the provided flow key. In which case, only outer fields are considered. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/route.c')
-rw-r--r--net/ipv4/route.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9d61e969446e..a4c477475f4c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1906,6 +1906,121 @@ out:
hash_keys->addrs.v4addrs.dst = key_iph->daddr;
}
+static u32 fib_multipath_custom_hash_outer(const struct net *net,
+ const struct sk_buff *skb,
+ bool *p_has_inner)
+{
+ u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+ struct flow_keys keys, hash_keys;
+
+ if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
+ return 0;
+
+ memset(&hash_keys, 0, sizeof(hash_keys));
+ skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
+
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
+ hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
+ hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
+ hash_keys.basic.ip_proto = keys.basic.ip_proto;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
+ hash_keys.ports.src = keys.ports.src;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
+ hash_keys.ports.dst = keys.ports.dst;
+
+ *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
+ return flow_hash_from_keys(&hash_keys);
+}
+
+static u32 fib_multipath_custom_hash_inner(const struct net *net,
+ const struct sk_buff *skb,
+ bool has_inner)
+{
+ u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+ struct flow_keys keys, hash_keys;
+
+ /* We assume the packet carries an encapsulation, but if none was
+ * encountered during dissection of the outer flow, then there is no
+ * point in calling the flow dissector again.
+ */
+ if (!has_inner)
+ return 0;
+
+ if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
+ return 0;
+
+ memset(&hash_keys, 0, sizeof(hash_keys));
+ skb_flow_dissect_flow_keys(skb, &keys, 0);
+
+ if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
+ return 0;
+
+ if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
+ hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
+ hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
+ } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
+ hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
+ hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
+ hash_keys.tags.flow_label = keys.tags.flow_label;
+ }
+
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
+ hash_keys.basic.ip_proto = keys.basic.ip_proto;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
+ hash_keys.ports.src = keys.ports.src;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
+ hash_keys.ports.dst = keys.ports.dst;
+
+ return flow_hash_from_keys(&hash_keys);
+}
+
+static u32 fib_multipath_custom_hash_skb(const struct net *net,
+ const struct sk_buff *skb)
+{
+ u32 mhash, mhash_inner;
+ bool has_inner = true;
+
+ mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
+ mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
+
+ return jhash_2words(mhash, mhash_inner, 0);
+}
+
+static u32 fib_multipath_custom_hash_fl4(const struct net *net,
+ const struct flowi4 *fl4)
+{
+ u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+ struct flow_keys hash_keys;
+
+ if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
+ return 0;
+
+ memset(&hash_keys, 0, sizeof(hash_keys));
+ hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
+ hash_keys.addrs.v4addrs.src = fl4->saddr;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
+ hash_keys.addrs.v4addrs.dst = fl4->daddr;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
+ hash_keys.basic.ip_proto = fl4->flowi4_proto;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
+ hash_keys.ports.src = fl4->fl4_sport;
+ if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
+ hash_keys.ports.dst = fl4->fl4_dport;
+
+ return flow_hash_from_keys(&hash_keys);
+}
+
/* if skb is set it will be used and fl4 can be NULL */
int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
const struct sk_buff *skb, struct flow_keys *flkeys)
@@ -1991,6 +2106,12 @@ int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
}
mhash = flow_hash_from_keys(&hash_keys);
break;
+ case 3:
+ if (skb)
+ mhash = fib_multipath_custom_hash_skb(net, skb);
+ else
+ mhash = fib_multipath_custom_hash_fl4(net, fl4);
+ break;
}
if (multipath_hash)