diff --git a/src/ipnetwork.rs b/src/ipnetwork.rs
new file mode 100644
index 0000000..727b4cd
--- /dev/null
+++ b/src/ipnetwork.rs
@@ -0,0 +1,152 @@
+use std::fmt;
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+
+// A network
+#[derive(Debug)]
+pub enum IpNetwork {
+    V4(Ipv4Network),
+    V6(Ipv6Network),
+}
+
+pub struct Ipv4Network {
+    addr: Ipv4Addr,
+    prefix: u8,
+}
+
+pub struct Ipv6Network {
+    addr: Ipv6Addr,
+    prefix: u8,
+}
+
+impl Ipv4Network {
+    pub fn new(addr: Ipv4Addr, prefix: u8) -> Ipv4Network {
+        Ipv4Network { addr: addr, prefix: prefix }
+    }
+
+    pub fn ip(&self) -> &Ipv4Addr {
+        &(self.addr)
+    }
+
+    pub fn prefix(&self) -> u8 {
+        self.prefix
+    }
+
+    pub fn mask_int(&self) -> u32 {
+        let prefix = self.prefix;
+        !(0xffffffff >> prefix)
+    }
+
+    pub fn mask(&self) -> Ipv4Addr {
+        let mask = self.mask_int();
+        Ipv4Network::int_to_ip(mask)
+    }
+
+    pub fn network_int(&self) -> u32 {
+        Ipv4Network::ip_to_int(*(self.ip())) & self.mask_int()
+    }
+
+    pub fn network(&self) -> Ipv4Addr {
+        Ipv4Network::int_to_ip(self.network_int())
+    }
+
+    fn ip_to_int(addr: Ipv4Addr) -> u32 {
+        let ip = addr.octets();
+        ((ip[0] as u32) << 24) + ((ip[1] as u32) << 16) + ((ip[2] as u32) << 8) + (ip[3] as u32)
+    }
+
+    fn int_to_ip(ip: u32) -> Ipv4Addr {
+        Ipv4Addr::new(((ip >> 24) & 0xff) as u8, ((ip >> 16) & 0xff) as u8,
+                     ((ip >> 8) & 0xff) as u8, (ip & 0xff) as u8)
+    }
+}
+
+impl Ipv6Network {
+    pub fn new(addr: Ipv6Addr, prefix: u8) -> Ipv6Network {
+        Ipv6Network { addr: addr, prefix: prefix }
+    }
+
+    pub fn ip(&self) -> &Ipv6Addr {
+        &(self.addr)
+    }
+
+    pub fn prefix(&self) -> u8 {
+        self.prefix
+    }
+}
+
+impl IpNetwork {
+    pub fn new(ip: IpAddr, prefix: u8) -> IpNetwork {
+        match ip {
+            IpAddr::V4(a) => IpNetwork::V4(Ipv4Network::new(a, prefix)),
+            IpAddr::V6(a) => IpNetwork::V6(Ipv6Network::new(a, prefix)),
+        }
+    }
+
+    pub fn ip(&self) -> IpAddr {
+        match *self {
+            IpNetwork::V4(ref a) => IpAddr::V4(*a.ip()),
+            IpNetwork::V6(ref a) => IpAddr::V6(*a.ip()),
+        }
+    }
+
+    pub fn prefix(&self) -> u8 {
+        match *self {
+            IpNetwork::V4(ref a) => a.prefix(),
+            IpNetwork::V6(ref a) => a.prefix(),
+        }
+    }
+}
+
+impl fmt::Debug for Ipv4Network {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{}/{}", self.ip(), self.prefix())
+    }
+}
+
+impl fmt::Debug for Ipv6Network {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{}/{}", self.ip(), self.prefix())
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::net::{Ipv4Addr, Ipv6Addr};
+    use super::*;
+
+    #[test]
+    fn create_v4() {
+        let cidr = Ipv4Network::new(Ipv4Addr::new(77, 88, 21, 11), 24);
+        assert_eq!(cidr.prefix(), 24);
+    }
+
+    #[test]
+    fn create_v6() {
+        let cidr = Ipv6Network::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 24);
+        assert_eq!(cidr.prefix(), 24);
+    }
+
+    #[test]
+    fn mask_int_v4() {
+        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 29);
+        assert_eq!(cidr.mask_int(), 4294967288);
+    }
+
+    #[test]
+    fn mask_v4() {
+        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 29);
+        assert_eq!(cidr.mask(), Ipv4Addr::new(255, 255, 255, 248));
+    }
+
+    #[test]
+    fn network_int_v4() {
+        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 25);
+        assert_eq!(cidr.network_int(), 1249764096);
+    }
+
+    #[test]
+    fn network_v4() {
+        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 25);
+        assert_eq!(cidr.network(), Ipv4Addr::new(74, 125, 227, 0));
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 2170b58..d808b18 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,156 +1,4 @@
 #![crate_type = "lib"]
 #![feature(ip_addr)]
 #[allow(dead_code)]
-
-use std::fmt;
-use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
-
-// A network
-#[derive(Debug)]
-pub enum IpNetwork {
-    V4(Ipv4Network),
-    V6(Ipv6Network),
-}
-
-pub struct Ipv4Network {
-    addr: Ipv4Addr,
-    prefix: u8,
-}
-
-pub struct Ipv6Network {
-    addr: Ipv6Addr,
-    prefix: u8,
-}
-
-impl Ipv4Network {
-    pub fn new(addr: Ipv4Addr, prefix: u8) -> Ipv4Network {
-        Ipv4Network { addr: addr, prefix: prefix }
-    }
-
-    pub fn ip(&self) -> &Ipv4Addr {
-        &(self.addr)
-    }
-
-    pub fn prefix(&self) -> u8 {
-        self.prefix
-    }
-
-    pub fn mask_int(&self) -> u32 {
-        let prefix = self.prefix;
-        !(0xffffffff >> prefix)
-    }
-
-    pub fn mask(&self) -> Ipv4Addr {
-        let mask = self.mask_int();
-        Ipv4Network::int_to_ip(mask)
-    }
-
-    pub fn network_int(&self) -> u32 {
-        Ipv4Network::ip_to_int(*(self.ip())) & self.mask_int()
-    }
-
-    pub fn network(&self) -> Ipv4Addr {
-        Ipv4Network::int_to_ip(self.network_int())
-    }
-
-    fn ip_to_int(addr: Ipv4Addr) -> u32 {
-        let ip = addr.octets();
-        ((ip[0] as u32) << 24) + ((ip[1] as u32) << 16) + ((ip[2] as u32) << 8) + (ip[3] as u32)
-    }
-
-    fn int_to_ip(ip: u32) -> Ipv4Addr {
-        Ipv4Addr::new(((ip >> 24) & 0xff) as u8, ((ip >> 16) & 0xff) as u8,
-                     ((ip >> 8) & 0xff) as u8, (ip & 0xff) as u8)
-    }
-}
-
-impl Ipv6Network {
-    pub fn new(addr: Ipv6Addr, prefix: u8) -> Ipv6Network {
-        Ipv6Network { addr: addr, prefix: prefix }
-    }
-
-    pub fn ip(&self) -> &Ipv6Addr {
-        &(self.addr)
-    }
-
-    pub fn prefix(&self) -> u8 {
-        self.prefix
-    }
-}
-
-impl IpNetwork {
-    pub fn new(ip: IpAddr, prefix: u8) -> IpNetwork {
-        match ip {
-            IpAddr::V4(a) => IpNetwork::V4(Ipv4Network::new(a, prefix)),
-            IpAddr::V6(a) => IpNetwork::V6(Ipv6Network::new(a, prefix)),
-        }
-    }
-
-    pub fn ip(&self) -> IpAddr {
-        match *self {
-            IpNetwork::V4(ref a) => IpAddr::V4(*a.ip()),
-            IpNetwork::V6(ref a) => IpAddr::V6(*a.ip()),
-        }
-    }
-
-    pub fn prefix(&self) -> u8 {
-        match *self {
-            IpNetwork::V4(ref a) => a.prefix(),
-            IpNetwork::V6(ref a) => a.prefix(),
-        }
-    }
-}
-
-impl fmt::Debug for Ipv4Network {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{}/{}", self.ip(), self.prefix())
-    }
-}
-
-impl fmt::Debug for Ipv6Network {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{}/{}", self.ip(), self.prefix())
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use std::net::{Ipv4Addr, Ipv6Addr};
-    use super::*;
-
-    #[test]
-    fn create_v4() {
-        let cidr = Ipv4Network::new(Ipv4Addr::new(77, 88, 21, 11), 24);
-        assert_eq!(cidr.prefix(), 24);
-    }
-
-    #[test]
-    fn create_v6() {
-        let cidr = Ipv6Network::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 24);
-        assert_eq!(cidr.prefix(), 24);
-    }
-
-    #[test]
-    fn mask_int_v4() {
-        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 29);
-        assert_eq!(cidr.mask_int(), 4294967288);
-    }
-
-    #[test]
-    fn mask_v4() {
-        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 29);
-        assert_eq!(cidr.mask(), Ipv4Addr::new(255, 255, 255, 248));
-    }
-
-    #[test]
-    fn network_int_v4() {
-        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 25);
-        assert_eq!(cidr.network_int(), 1249764096);
-    }
-
-    #[test]
-    fn network_v4() {
-        let cidr = Ipv4Network::new(Ipv4Addr::new(74, 125, 227, 0), 25);
-        assert_eq!(cidr.network(), Ipv4Addr::new(74, 125, 227, 0));
-    }
-}
+pub mod ipnetwork;