netfilter: conntrack: switch to siphash

Replace jhash in conntrack and nat core with siphash.

While at it, use the netns mix value as part of the input key
rather than abuse the seed value.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 18 insertions, 13 deletions

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index cdd8a1dc2275..da2650f872e1 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -21,7 +21,6 @@
 #include <linux/stddef.h>
 #include <linux/slab.h>
 #include <linux/random.h>
-#include <linux/jhash.h>
 #include <linux/siphash.h>
 #include <linux/err.h>
 #include <linux/percpu.h>
@@ -184,25 +183,31 @@ EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
 unsigned int nf_conntrack_max __read_mostly;
 EXPORT_SYMBOL_GPL(nf_conntrack_max);
 seqcount_spinlock_t nf_conntrack_generation __read_mostly;
-static unsigned int nf_conntrack_hash_rnd __read_mostly;
+static siphash_key_t nf_conntrack_hash_rnd __read_mostly;
 
 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
 			      const struct net *net)
 {
-	unsigned int n;
-	u32 seed;
+	struct {
+		struct nf_conntrack_man src;
+		union nf_inet_addr dst_addr;
+		u32 net_mix;
+		u16 dport;
+		u16 proto;
+	} __aligned(SIPHASH_ALIGNMENT) combined;
 
 	get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
 
-	/* The direction must be ignored, so we hash everything up to the
-	 * destination ports (which is a multiple of 4) and treat the last
-	 * three bytes manually.
-	 */
-	seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
-	n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
-	return jhash2((u32 *)tuple, n, seed ^
-		      (((__force __u16)tuple->dst.u.all << 16) |
-		      tuple->dst.protonum));
+	memset(&combined, 0, sizeof(combined));
+
+	/* The direction must be ignored, so handle usable members manually. */
+	combined.src = tuple->src;
+	combined.dst_addr = tuple->dst.u3;
+	combined.net_mix = net_hash_mix(net);
+	combined.dport = (__force __u16)tuple->dst.u.all;
+	combined.proto = tuple->dst.protonum;
+
+	return (u32)siphash(&combined, sizeof(combined), &nf_conntrack_hash_rnd);
 }
 
 static u32 scale_hash(u32 hash)