Add geoip data and 451 handler

src/web/ip_blocking.rs

@@ -0,0 +1,58 @@
+use std::net::Ipv4Addr;
+
+struct IpBlocking {
+    upper_ips: Vec<u32>,
+    lower_ips: Vec<u32>,
+}
+
+type E = Box<dyn std::error::Error>;
+
+impl IpBlocking {
+    fn from_path(path: &str) -> Result<Self, E> {
+        let mut upper_ips: Vec<u32> = vec![];
+        let mut lower_ips: Vec<u32> = vec![];
+        let mut reader = csv::Reader::from_path(path)?;
+
+        for record in reader.records() {
+            let record = record?;
+            let ip_range: Option<(u32, u32)> =
+                record.get(0).map(|ip| ip.parse::<Ipv4Addr>().ok()).flatten().and_then(
+                    |ip_start| {
+                        record
+                            .get(1)
+                            .map(|ip| ip.parse::<Ipv4Addr>().ok())
+                            .flatten()
+                            .map(|ip_end| (ip_start.into(), ip_end.into()))
+                    },
+                );
+
+            if let Some((ip_start, ip_end)) = ip_range {
+                upper_ips.push(ip_end);
+                lower_ips.push(ip_start);
+            }
+        }
+
+        // Should already be sorted but just in case
+        upper_ips.sort_unstable();
+        lower_ips.sort_unstable();
+
+        Ok(Self { upper_ips, lower_ips })
+    }
+
+    fn contains<I: Into<u32>>(&self, ip: I) -> bool {
+        let ip: u32 = ip.into();
+
+        let mut prev_index = self.upper_ips.len() - 1;
+        let mut index = self.upper_ips.len() / 2;
+        loop {
+            if self.upper_ips[index] <= ip && self.lower_ips[index] >= ip {
+                return true;
+            }
+
+            let diff = self.upper_ips.len() - index;
+            if self.upper_ips[index] < ip {
+                index += diff / 2;
+            }
+        }
+    }
+}