Add excludes to filter module

src/filter/excludes.rs

@@ -0,0 +1,78 @@
+use regex::RegexSet;
+use std::net::IpAddr;
+
+use crate::Uri;
+
+/// Exclude configuration for the link checker.
+/// You can ignore links based on regex patterns or pre-defined IP ranges.
+#[derive(Clone, Debug)]
+pub struct Excludes {
+    pub regex: Option<RegexSet>,
+    /// Example: 192.168.0.1
+    pub private_ips: bool,
+    /// Example: 169.254.0.0
+    pub link_local_ips: bool,
+    /// For IPv4: 127.0. 0.1/8
+    /// For IPv6: ::1/128
+    pub loopback_ips: bool,
+    /// Example: octocat@github.com
+    pub mail: bool,
+}
+
+impl Default for Excludes {
+    fn default() -> Self {
+        Self {
+            regex: None,
+            private_ips: false,
+            link_local_ips: false,
+            loopback_ips: false,
+            mail: false,
+        }
+    }
+}
+
+impl Excludes {
+    pub fn regex(&self, input: &str) -> bool {
+        if let Some(excludes) = &self.regex {
+            if excludes.is_match(input) {
+                return true;
+            }
+        }
+        false
+    }
+
+    pub fn ip(&self, uri: &Uri) -> bool {
+        if let Some(ipaddr) = uri.host_ip() {
+            if self.loopback_ips && ipaddr.is_loopback() {
+                return true;
+            }
+
+            // Note: in a pathological case, an IPv6 address can be IPv4-mapped
+            //       (IPv4 address embedded in a IPv6).  We purposefully
+            //       don't deal with it here, and assume if an address is IPv6,
+            //       we shouldn't attempt to map it to IPv4.
+            //       See: https://tools.ietf.org/html/rfc4291#section-2.5.5.2
+            if let IpAddr::V4(v4addr) = ipaddr {
+                if self.private_ips && v4addr.is_private() {
+                    return true;
+                }
+                if self.link_local_ips && v4addr.is_link_local() {
+                    return true;
+                }
+            }
+        }
+
+        false
+    }
+
+    pub fn is_mail_excluded(&self) -> bool {
+        self.mail
+    }
+
+    pub fn is_empty(&self) -> bool {
+        match &self.regex {
+            None => true,
+            Some(regex_set) => regex_set.is_empty(),
+        }
+    }
+}