Allow embedding of CORS proxy in fetch relay_url (#1189)

Extends the syntax of relay_url for fetch to:

    fetch[:CORS-PROXY-URL]

where CORS-PROXY-URL is a full URL pointing to the CORS proxy server, for example:

    fetch:https://example.com/?url=

* pass options.net_device to NetworkAdapter constructors

- aligned construction of WispNetworkAdapter and FetchNetworkAdapter classes
- supported members in object options.net_device (all optional):
  id, router_mac, router_ip, vm_ip, masquerade, dns_method, doh_server, cors_proxy
- completed support for free choice between fake network DNS methods "static" and "doh"

src/browser/fetch_network.js

@@ -16,9 +16,10 @@ function FetchNetworkAdapter(bus, config)
     this.vm_ip = new Uint8Array((config.vm_ip || "192.168.86.100").split(".").map(function(x) { return parseInt(x, 10); }));
     this.masquerade = config.masquerade === undefined || !!config.masquerade;
     this.vm_mac = new Uint8Array(6);
+    this.dns_method = config.dns_method || "static";
+    this.doh_server = config.doh_server;
     this.tcp_conn = {};
     this.eth_encoder_buf = create_eth_encoder_buf();
-    this.dns_method = "static";
 
     // Ex: 'https://corsproxy.io/?'
     this.cors_proxy = config.cors_proxy;

src/browser/main.js

@@ -1737,6 +1737,11 @@
             settings.relay_url = $("relay_url").value;
             if(!DEFAULT_NETWORKING_PROXIES.includes(settings.relay_url)) new_query_args.set("relay_url", settings.relay_url);
         }
+        if(settings.relay_url.startsWith("fetch:"))
+        {
+            settings.cors_proxy = settings.relay_url.slice(6);
+            settings.relay_url = "fetch";
+        }
         settings.disable_audio = $("disable_audio").checked || settings.disable_audio;
         if(settings.disable_audio) new_query_args.set("mute", "1");
 
@@ -1852,6 +1857,7 @@
             net_device: {
                 type: settings.net_device_type || "ne2k",
                 relay_url: settings.relay_url,
+                cors_proxy: settings.cors_proxy
             },
             autostart: true,
 

src/browser/starter.js

@@ -313,11 +313,11 @@ V86.prototype.continue_init = async function(emulator, options)
         // TODO: remove bus, use direct calls instead
         if(relay_url === "fetch")
         {
-            this.network_adapter = new FetchNetworkAdapter(this.bus);
+            this.network_adapter = new FetchNetworkAdapter(this.bus, options.net_device);
         }
         else if(relay_url.startsWith("wisp://") || relay_url.startsWith("wisps://"))
         {
-            this.network_adapter = new WispNetworkAdapter(relay_url, this.bus, options);
+            this.network_adapter = new WispNetworkAdapter(relay_url, this.bus, options.net_device);
         }
         else
         {

src/browser/wisp_network.js

@@ -3,6 +3,7 @@
 /**
  * @constructor
  *
+ * @param {String} wisp_url
  * @param {BusConnector} bus
  * @param {*=} config
  */
@@ -21,10 +22,10 @@ function WispNetworkAdapter(wisp_url, bus, config)
     this.vm_ip = new Uint8Array((config.vm_ip || "192.168.86.100").split(".").map(function(x) { return parseInt(x, 10); }));
     this.masquerade = config.masquerade === undefined || !!config.masquerade;
     this.vm_mac = new Uint8Array(6);
+    this.dns_method = config.dns_method || "doh";
+    this.doh_server = config.doh_server;
     this.tcp_conn = {};
     this.eth_encoder_buf = create_eth_encoder_buf();
-    this.dns_method = "doh";
-    this.doh_server = config.doh_server;
 
     this.bus.register("net" + this.id + "-mac", function(mac) {
         this.vm_mac = new Uint8Array(mac.split(":").map(function(x) { return parseInt(x, 16); }));