From 62a1d8a2d312c61673f868878efdcb747c63f772 Mon Sep 17 00:00:00 2001
From: Matthew Wild <mwild1@gmail.com>
Date: Sat, 18 May 2013 16:45:29 +0100
Subject: util.ip: Add CIDR notation parsing and matching

---
 util/ip.lua | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

(limited to 'util/ip.lua')

diff --git a/util/ip.lua b/util/ip.lua
index 20ea3dd7..8cf0076e 100644
--- a/util/ip.lua
+++ b/util/ip.lua
@@ -215,5 +215,28 @@ function ip_methods:private()
 	return private;
 end
 
+local function parse_cidr(cidr)
+	local bits;
+	local ip_len = cidr:find("/", 1, true);
+	if ip_len then
+		bits = tonumber(cidr:sub(ip_len+1, -1));
+		cidr = cidr:sub(1, ip_len-1);
+	end
+	return new_ip(cidr), bits;
+end
+
+local function match(ipA, ipB, bits)
+	local common_bits = commonPrefixLength(ipA, ipB);
+	if not bits then
+		return ipA == ipB;
+	end
+	if bits and ipB.proto == "IPv4" then
+		common_bits = common_bits - 96; -- v6 mapped addresses always share these bits
+	end
+	return common_bits >= bits;
+end
+
 return {new_ip = new_ip,
-	commonPrefixLength = commonPrefixLength};
+	commonPrefixLength = commonPrefixLength,
+	parse_cidr = parse_cidr,
+	match=match};
-- 
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