From 54ac0beceedb9b36eb58dd8599ba903c668382f6 Mon Sep 17 00:00:00 2001
From: Jan Moskyto Matejka <mq@ucw.cz>
Date: Thu, 12 May 2016 16:16:25 +0200
Subject: [PATCH] Hash: fixed rta hashing wrt. structure padding

---
 lib/hash.h     | 38 +++++++++++++++++++++++++++++---------
 nest/rt-attr.c | 19 +++++++++++++++++--
 2 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/lib/hash.h b/lib/hash.h
index b0641466..b86a2eb1 100644
--- a/lib/hash.h
+++ b/lib/hash.h
@@ -178,16 +178,36 @@
 
 #define HASH_WALK_FILTER_END } while (0)
 
-static inline uint
-mem_hash(void *p, int s)
-{
-  const char *pp = p;
-  const u64 multiplier = 0xb38bc09a61202731ULL;
-  u64 value = 0x001047d54778bcafULL;
-  int i;
-  for (i=0;i<s;i++)
-    value = value*multiplier + pp[i];
+typedef mem_hash_t  u64;
 
+static inline void
+mem_hash_init(mem_hash_t *h)
+{
+  *h = 0x001047d54778bcafULL;
+}
+
+static inline void
+mem_hash_mix(mem_hash_t *h, void *p, int s)
+{
+  const u64 multiplier = 0xb38bc09a61202731ULL;
+  const char *pp = p;
+  uint i;
+  for (i=0; i<s; i++)
+    *h = *h * multiplier + pp[i];
+}
+
+static inline uint
+mem_hash_value(mem_hash_t *h)
+{
   return ((value >> 32) ^ (value & 0xffffffff));
 }
 
+static inline uint
+mem_hash(void *p, int s)
+{
+  static mem_hash_t h;
+  mem_hash_init(&h);
+  mem_hash_mix(&h, p, s);
+  return mem_hash_value(&h);
+}
+
diff --git a/nest/rt-attr.c b/nest/rt-attr.c
index 7d9605c2..62340530 100644
--- a/nest/rt-attr.c
+++ b/nest/rt-attr.c
@@ -946,8 +946,23 @@ rta_alloc_hash(void)
 static inline uint
 rta_hash(rta *a)
 {
-  return mem_hash(((void *)a) + offsetof(rta, src), sizeof(rta) - offsetof(rta, src)) ^
-	 mpnh_hash(a->nexthops) ^ ea_hash(a->eattrs);
+  mem_hash_t h;
+  mem_hash_init(&h);
+#define MIX(f) mem_hash_mix(&h, &(rta->f), sizeof(rta->f));
+  MIX(src);
+  MIX(hostentry);
+  MIX(iface);
+  MIX(gw);
+  MIX(from);
+  MIX(igp_metric);
+  MIX(source);
+  MIX(scope);
+  MIX(cast);
+  MIX(dest);
+  MIX(flags);
+  MIX(aflags);
+
+  return mem_hash_value(&h) ^ mpnh_hash(a->nexthops) ^ ea_hash(a->eattrs);
 }
 
 static inline int