feat: add congestion control to TCP implementation (#220)

Closes #219

This PR adds congestion control to the TCP implementation

Author: MegaRedHand

src/packets/ethernet.ts

@@ -116,7 +116,6 @@ export class EthernetFrame {
   type: number;
   // 46-1500 bytes
   // If the payload is smaller than 46 bytes, it is padded.
-  // TODO: make this an interface
   // The payload
   payload: FramePayload;
   // 4 bytes

src/programs/http_client.ts

@@ -9,19 +9,35 @@ import { ViewHost } from "../types/view-devices";
 import { TOOLTIP_KEYS } from "../utils/constants/tooltips_constants";
 import { ProgramBase } from "./program_base";
 
+const RESOURCE_MAP = new Map([
+  ["/small", generateResource(1024)],
+  ["/medium", generateResource(102400)],
+  ["/large", generateResource(10485760)],
+]);
+
+function generateResource(size: number): Uint8Array {
+  const resource = new Uint8Array(size);
+  for (let i = 0; i < size; i++) {
+    resource[i] = Math.floor(Math.random() * 256);
+  }
+  return resource;
+}
+
 export class HttpClient extends ProgramBase {
   static readonly PROGRAM_NAME = TOOLTIP_KEYS.SEND_HTTP_REQUEST;
 
   private dstId: DeviceId;
+  private resource: string;
 
   protected _parseInputs(inputs: string[]): void {
-    if (inputs.length !== 1) {
+    if (inputs.length !== 2) {
       console.error(
-        "HttpClient requires 1 input. " + inputs.length + " were given.",
+        "HttpClient requires 2 input. " + inputs.length + " were given.",
       );
       return;
     }
     this.dstId = parseInt(inputs[0]);
+    this.resource = inputs[1];
   }
 
   protected _run() {
@@ -51,19 +67,19 @@ export class HttpClient extends ProgramBase {
       return;
     }
 
-    // Encode dummy HTTP request
-    const httpRequest = "GET / HTTP/1.1\r\nHost: " + dstDevice.ip + "\r\n\r\n";
-    const content = new TextEncoder().encode(httpRequest);
+    // Encode HTTP request
+    const httpRequest = getContentRequest(
+      this.runner.ip.toString(),
+      this.resource,
+    );
 
     // Write request
     const socket = await this.runner.tcpConnect(this.dstId);
     if (!socket) {
-      console.warn(
-        "HttpClient failed to connect to socket. Program cancelled.",
-      );
+      console.warn("HttpClient failed to connect");
       return;
     }
-    const wrote = await socket.write(content);
+    const wrote = await socket.write(httpRequest);
     if (wrote < 0) {
       console.error("HttpClient failed to write to socket");
       return;
@@ -74,20 +90,39 @@ export class HttpClient extends ProgramBase {
 
     // Read response
     const buffer = new Uint8Array(1024);
-    const readLength = await socket.readAll(buffer);
-    if (readLength < 0) {
-      console.error("HttpClient failed to read from socket");
-      return;
+    const expectedLength = RESOURCE_MAP.get(this.resource)?.length || 0;
+    let totalRead = 0;
+    while (totalRead < expectedLength) {
+      const readLength = await socket.read(buffer);
+      if (readLength < 0) {
+        console.error("HttpClient failed to read from socket");
+        return;
+      }
+      totalRead += readLength;
     }
   }
 
   static getProgramInfo(viewgraph: ViewGraph, srcId: DeviceId): ProgramInfo {
+    const sizeOptions = [
+      { value: "/small", text: "1 KB" },
+      { value: "/medium", text: "100 KB" },
+      { value: "/large", text: "10 MB" },
+    ];
+
     const programInfo = new ProgramInfo(this.PROGRAM_NAME);
     programInfo.withDestinationDropdown(viewgraph, srcId, Layer.App);
+    programInfo.withDropdown("Size of requested resource", sizeOptions);
     return programInfo;
   }
 }
 
+function getContentRequest(host: string, resource: string): Uint8Array {
+  const httpRequest =
+    "GET " + resource + " HTTP/1.1\r\nHost: " + host + "\r\n\r\n";
+  const content = new TextEncoder().encode(httpRequest);
+  return content;
+}
+
 export class HttpServer extends ProgramBase {
   static readonly PROGRAM_NAME = TOOLTIP_KEYS.SERVE_HTTP_REQUESTS;
 
@@ -156,20 +191,37 @@ export class HttpServer extends ProgramBase {
     const buffer = new Uint8Array(1024).fill(0);
     const readLength = await socket.readAll(buffer);
 
-    // eslint-disable-next-line @typescript-eslint/no-unused-vars
     const readContents = buffer.slice(0, readLength);
     if (readLength < 0) {
       console.error("HttpServer failed to read from socket");
       return;
     }
 
-    // TODO: validate request
+    const requestContents = new TextDecoder().decode(readContents);
+    const matches = requestContents.match(/GET (.+) HTTP\/1.1/);
+    if (!matches || matches.length < 2) {
+      console.error("HttpServer failed to parse request");
+      return;
+    }
+    const resourceContents = RESOURCE_MAP.get(matches[1]);
+    if (!resourceContents) {
+      console.error("HttpServer failed to find requested resource");
+      return;
+    }
 
     // Encode dummy HTTP response
-    const httpResponse = "HTTP/1.1 200 OK\r\nContent-Length: 0\r\n\r\n";
+    const httpResponse =
+      "HTTP/1.1 200 OK\r\nContent-Length: " +
+      resourceContents.length +
+      "\r\n\r\n";
     const content = new TextEncoder().encode(httpResponse);
     const wrote = await socket.write(content);
-    if (wrote < 0) {
+    if (wrote <= 0) {
+      console.error("HttpServer failed to write to socket");
+      return;
+    }
+    const wrote2 = await socket.write(resourceContents);
+    if (wrote2 <= 0) {
       console.error("HttpServer failed to write to socket");
       return;
     }