Merge branch 'master' into theme-auto-detection

src/core/config/Categories.json

@@ -235,6 +235,7 @@
             "Parse IP range",
             "Parse IPv6 address",
             "Parse IPv4 header",
+            "Strip IPv4 header",
             "Parse TCP",
             "Strip TCP header",
             "Parse TLS record",

src/core/operations/AddLineNumbers.mjs

@@ -22,7 +22,13 @@ class AddLineNumbers extends Operation {
         this.description = "Adds line numbers to the output.";
         this.inputType = "string";
         this.outputType = "string";
-        this.args = [];
+        this.args = [
+            {
+                "name": "Offset",
+                "type": "number",
+                "value": 0
+            }
+        ];
     }
 
     /**
@@ -33,10 +39,11 @@ class AddLineNumbers extends Operation {
     run(input, args) {
         const lines = input.split("\n"),
             width = lines.length.toString().length;
+        const offset = args[0] ? parseInt(args[0], 10) : 0;
         let output = "";
 
         for (let n = 0; n < lines.length; n++) {
-            output += (n+1).toString().padStart(width, " ") + " " + lines[n] + "\n";
+            output += (n+1+offset).toString().padStart(width, " ") + " " + lines[n] + "\n";
         }
         return output.slice(0, output.length-1);
     }

src/core/operations/StripIPv4Header.mjs

@@ -0,0 +1,57 @@
+/**
+ * @author c65722 []
+ * @copyright Crown Copyright 2024
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import Stream from "../lib/Stream.mjs";
+
+/**
+ * Strip IPv4 header operation
+ */
+class StripIPv4Header extends Operation {
+
+    /**
+     * StripIPv4Header constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Strip IPv4 header";
+        this.module = "Default";
+        this.description = "Strips the IPv4 header from an IPv4 packet, outputting the payload.";
+        this.infoURL = "https://wikipedia.org/wiki/IPv4";
+        this.inputType = "ArrayBuffer";
+        this.outputType = "ArrayBuffer";
+        this.args = [];
+    }
+
+    /**
+     * @param {ArrayBuffer} input
+     * @param {Object[]} args
+     * @returns {ArrayBuffer}
+     */
+    run(input, args) {
+        const MIN_HEADER_LEN = 20;
+
+        const s = new Stream(new Uint8Array(input));
+        if (s.length < MIN_HEADER_LEN) {
+            throw new OperationError("Input length is less than minimum IPv4 header length");
+        }
+
+        const ihl = s.readInt(1) & 0x0f;
+        const dataOffsetBytes = ihl * 4;
+        if (s.length < dataOffsetBytes) {
+            throw new OperationError("Input length is less than IHL");
+        }
+
+        s.moveTo(dataOffsetBytes);
+
+        return s.getBytes().buffer;
+    }
+
+}
+
+export default StripIPv4Header;