From 8b235297a596f3ddd6050994c845e2d7e22e72b2 Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Mon, 23 Nov 2015 15:24:33 +0100
Subject: [PATCH] util: add function for IP address hashing

Move the hashing function from find_slot() in ntp_sources to make it
available to clientlog and improve the hashing a bit.
---
 ntp_sources.c | 20 +++++---------------
 util.c        | 28 ++++++++++++++++++++++++++++
 util.h        |  1 +
 3 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/ntp_sources.c b/ntp_sources.c
index eca681cc..e6ac8b0b 100644
--- a/ntp_sources.c
+++ b/ntp_sources.c
@@ -202,26 +202,16 @@ find_slot(NTP_Remote_Address *remote_addr, int *slot, int *found)
   uint32_t hash;
   unsigned int i, size;
   unsigned short port;
-  uint8_t *ip6;
 
   size = ARR_GetSize(records);
   
-  switch (remote_addr->ip_addr.family) {
-    case IPADDR_INET6:
-      ip6 = remote_addr->ip_addr.addr.in6;
-      hash = (ip6[0] ^ ip6[4] ^ ip6[8] ^ ip6[12]) |
-           (ip6[1] ^ ip6[5] ^ ip6[9] ^ ip6[13]) << 8 |
-           (ip6[2] ^ ip6[6] ^ ip6[10] ^ ip6[14]) << 16 |
-           (ip6[3] ^ ip6[7] ^ ip6[11] ^ ip6[15]) << 24;
-      break;
-    case IPADDR_INET4:
-      hash = remote_addr->ip_addr.addr.in4;
-      break;
-    default:
-      *found = *slot = 0;
-      return;
+  if (remote_addr->ip_addr.family != IPADDR_INET4 &&
+      remote_addr->ip_addr.family != IPADDR_INET6) {
+    *found = *slot = 0;
+    return;
   }
 
+  hash = UTI_IPToHash(&remote_addr->ip_addr);
   port = remote_addr->port;
 
   for (i = 0; i < size / 2; i++) {
diff --git a/util.c b/util.c
index fc3a81c3..da70f0bd 100644
--- a/util.c
+++ b/util.c
@@ -359,6 +359,34 @@ UTI_IPToRefid(IPAddr *ip)
 
 /* ================================================== */
 
+uint32_t
+UTI_IPToHash(IPAddr *ip)
+{
+  unsigned char *addr;
+  unsigned int i, len;
+  uint32_t hash;
+
+  switch (ip->family) {
+    case IPADDR_INET4:
+      addr = (unsigned char *)&ip->addr.in4;
+      len = sizeof (ip->addr.in4);
+      break;
+    case IPADDR_INET6:
+      addr = ip->addr.in6;
+      len = sizeof (ip->addr.in6);
+      break;
+    default:
+      return 0;
+  }
+
+  for (i = 0, hash = 0; i < len; i++)
+    hash = 71 * hash + addr[i];
+
+  return hash;
+}
+
+/* ================================================== */
+
 void
 UTI_IPHostToNetwork(IPAddr *src, IPAddr *dest)
 {
diff --git a/util.h b/util.h
index f0cb6105..78b7d71a 100644
--- a/util.h
+++ b/util.h
@@ -82,6 +82,7 @@ extern char *UTI_IPToString(IPAddr *ip);
 
 extern int UTI_StringToIP(const char *addr, IPAddr *ip);
 extern uint32_t UTI_IPToRefid(IPAddr *ip);
+extern uint32_t UTI_IPToHash(IPAddr *ip);
 extern void UTI_IPHostToNetwork(IPAddr *src, IPAddr *dest);
 extern void UTI_IPNetworkToHost(IPAddr *src, IPAddr *dest);
 extern int UTI_CompareIPs(IPAddr *a, IPAddr *b, IPAddr *mask);
-- 
2.47.2