[src/trunk]: src/sys/net/npf sess_hash_bucket: convert to murmurhash2, includ...

[rmind <rmind%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3cacabf711a6
branches:  trunk
changeset: 790202:3cacabf711a6
user:      rmind <rmind%NetBSD.org@localhost>
date:      Thu Sep 26 00:24:36 2013 +0000

description:
sess_hash_bucket: convert to murmurhash2, include ports, use random seed.

diffstat:

 sys/net/npf/npf_session.c |  20 +++++++++++---------
 1 files changed, 11 insertions(+), 9 deletions(-)

diffs (63 lines):

diff -r d80fcf638a4e -r 3cacabf711a6 sys/net/npf/npf_session.c
--- a/sys/net/npf/npf_session.c Wed Sep 25 19:39:47 2013 +0000
+++ b/sys/net/npf/npf_session.c Thu Sep 26 00:24:36 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: npf_session.c,v 1.24 2013/06/02 02:20:04 rmind Exp $   */
+/*     $NetBSD: npf_session.c,v 1.25 2013/09/26 00:24:36 rmind Exp $   */
 
 /*-
  * Copyright (c) 2010-2013 The NetBSD Foundation, Inc.
@@ -92,7 +92,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: npf_session.c,v 1.24 2013/06/02 02:20:04 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: npf_session.c,v 1.25 2013/09/26 00:24:36 rmind Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -102,6 +102,7 @@
 
 #include <sys/atomic.h>
 #include <sys/condvar.h>
+#include <sys/cprng.h>
 #include <sys/hash.h>
 #include <sys/kmem.h>
 #include <sys/kthread.h>
@@ -200,6 +201,7 @@
 static kmutex_t                        sess_lock       __cacheline_aligned;
 static kcondvar_t              sess_cv         __cacheline_aligned;
 static struct npf_sesslist     sess_gc_list    __cacheline_aligned;
+static uint32_t                        sess_hash_seed  __read_mostly;
 
 static void    npf_session_worker(void);
 static void    npf_session_destroy(npf_session_t *);
@@ -222,6 +224,7 @@
        LIST_INIT(&sess_gc_list);
        sess_hashtbl = NULL;
 
+       sess_hash_seed = cprng_fast32();
        npf_worker_register(npf_session_worker);
 }
 
@@ -305,14 +308,13 @@
     const npf_sentry_t *sen)
 {
        const int sz = sen->se_alen;
-       uint32_t hash, mix;
+       uint32_t hash, mix[2];
 
-       /*
-        * Sum protocol, interface and both addresses (for both directions).
-        */
-       mix = scid->proto + scid->if_idx;
-       mix += npf_addr_sum(sz, &sen->se_src_addr, &sen->se_dst_addr);
-       hash = hash32_buf(&mix, sizeof(uint32_t), HASH32_BUF_INIT);
+       mix[0] = (scid->proto ^ scid->if_idx) << 16;
+       mix[0] |= sen->se_src_id ^ sen->se_dst_id;
+       mix[1] = npf_addr_sum(sz, &sen->se_src_addr, &sen->se_dst_addr);
+       hash = murmurhash2(mix, sizeof(mix), sess_hash_seed);
+
        return &stbl[hash & SESS_HASH_MASK];
 }