[PATCH v4 net-next 07/11] net: Get rid of IPv6 hash addresses flow keys

[Tom Herbert <tom@herbertland.com>]

We don't need to return the IPv6 address hash as part of flow keys.
In general, using the IPv6 address hash is risky in a hash value
since the underlying use of xor provides no entropy. If someone
really needs the hash value they can get it from the full IPv6
addresses in flow keys (e.g. from flow_get_u32_src).

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 include/net/flow_dissector.h |  1 -
 net/core/flow_dissector.c    | 17 -----------------
 2 files changed, 18 deletions(-)

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 3ee606a..59f00f9 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -103,7 +103,6 @@ enum flow_dissector_key_id {
 	FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
 	FLOW_DISSECTOR_KEY_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
 	FLOW_DISSECTOR_KEY_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
-	FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS, /* struct flow_dissector_key_addrs */
 	FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
 	FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
 	FLOW_DISSECTOR_KEY_TIPC_ADDRS, /* struct flow_dissector_key_tipc_addrs */
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 8d6f089..44e47c5 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -200,19 +200,6 @@ ipv6:
 		nhoff += sizeof(struct ipv6hdr);
 
 		if (skb_flow_dissector_uses_key(flow_dissector,
-						FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
-			key_addrs = skb_flow_dissector_target(flow_dissector,
-							      FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
-							      target_container);
-
-			key_addrs->v4addrs.src =
-				(__force __be32)ipv6_addr_hash(&iph->saddr);
-			key_addrs->v4addrs.dst =
-				(__force __be32)ipv6_addr_hash(&iph->daddr);
-			key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
-			goto flow_label;
-		}
-		if (skb_flow_dissector_uses_key(flow_dissector,
 						FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 			struct flow_dissector_key_ipv6_addrs *key_ipv6_addrs;
 
@@ -651,10 +638,6 @@ static const struct flow_dissector_key flow_keys_dissector_keys[] = {
 		.offset = offsetof(struct flow_keys, addrs.v6addrs),
 	},
 	{
-		.key_id = FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
-		.offset = offsetof(struct flow_keys, addrs.v4addrs),
-	},
-	{
 		.key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 		.offset = offsetof(struct flow_keys, addrs.tipcaddrs),
 	},
-- 
1.8.1