init

workers/session-proxy/ip-parser.ts

@@ -0,0 +1,64 @@
+export default class IPParser {
+  /**
+   * Parse and validate an IP address (IPv4 only for simplicity).
+   * @param {string} ip - The IP address to parse.
+   * @returns {number[]} - Parsed IP address as an array of numbers.
+   * @throws {Error} - If the IP is invalid.
+   */
+  static parseIP(ip) {
+    const octets = ip?.split(".");
+    if (octets?.length !== 4) {
+      throw new Error("Invalid IP address format");
+    }
+    return octets.map((octet) => {
+      const num = parseInt(octet, 10);
+      if (isNaN(num) || num < 0 || num > 255) {
+        throw new Error("Invalid IP address octet");
+      }
+      return num;
+    });
+  }
+
+  /**
+   * Convert an IP address to a 32-bit integer for comparison.
+   * @param {number[]} ipArray - IP address as an array of numbers.
+   * @returns {number} - 32-bit integer representation of the IP.
+   * @private
+   */
+  static #ipToInt(ipArray) {
+    return (
+      ((ipArray[0] << 24) |
+        (ipArray[1] << 16) |
+        (ipArray[2] << 8) |
+        ipArray[3]) >>>
+      0
+    ); // Ensure unsigned 32-bit
+  }
+
+  /**
+   * Check if an IP is within a given CIDR range.
+   * @param {string} ip - The IP address to check.
+   * @param {string} cidr - CIDR range (e.g., "192.168.0.0/24").
+   * @returns {boolean} - True if the IP is within the range, otherwise false.
+   * @throws {Error} - If either the IP or CIDR format is invalid.
+   */
+  static isInRange(ip, cidr) {
+    if (!cidr || typeof cidr !== "string" || cidr.length < 0) {
+      return false;
+    }
+
+    const [range, prefixLength] = cidr.split("/");
+    if (!prefixLength) {
+      throw new Error("Invalid CIDR format");
+    }
+
+    const ipArray = IPParser.parseIP(ip);
+    const rangeArray = IPParser.parseIP(range);
+
+    const ipInt = IPParser.#ipToInt(ipArray);
+    const rangeInt = IPParser.#ipToInt(rangeArray);
+
+    const mask = ~(2 ** (32 - parseInt(prefixLength, 10)) - 1) >>> 0;
+    return (rangeInt & mask) === (ipInt & mask);
+  }
+}