v0.2.1: fix PRI/HTTP2-preface leak + shrink SNI-rewrite list

Two bug fixes surfaced in user testing:

1. Invalid HTTP methods forwarded to Apps Script
   - Browser/xray sent HTTP/2 PRI preface through our MITM despite ALPN
     being set to http/1.1 only (some clients ignore ALPN).
   - Our parser accepted 'PRI' as a method and forwarded to Apps Script,
     which rejected it: 'Exception: parameter provided with invalid value: method'.
   - Fix: validate method against the standard list (GET/POST/PUT/DELETE/
     HEAD/OPTIONS/PATCH/TRACE/CONNECT) at parse time. Non-matching requests
     close the connection cleanly instead of forwarding garbage.

2. YouTube video playback broken by over-broad SNI-rewrite list
   - Previous list included googlevideo.com, ytimg.com, doubleclick.net,
     etc. -- but these are served from SEPARATE CDN pools, NOT from
     Google's 216.239.38.120 frontend. Rewriting sent traffic to the
     wrong backend, which Google dropped.
   - Shrunk to a conservative list that's actually served from the
     main Google frontend: youtube.com, youtu.be, youtube-nocookie.com,
     fonts.googleapis.com. Everything else falls through to MITM+relay
     (slower but actually works).
   - YouTube video chunks now route through Apps Script which is slow
     and quota-limited. This is a known limitation inherent to the
     approach; same issue exists in the original Python version.

Author: therealaleph

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "mhrv-rs"
-version = "0.2.0"
+version = "0.2.1"
 edition = "2021"
 description = "Rust port of MasterHttpRelayVPN -- DPI bypass via Google Apps Script relay with domain fronting"
 license = "MIT"

Cargo.toml

@@ -14,22 +14,16 @@ use crate::config::Config;
 use crate::domain_fronter::DomainFronter;
 use crate::mitm::MitmCertManager;
 
+// Domains that are served from Google's core frontend IP pool and therefore
+// respond correctly when we connect to `google_ip` with SNI=`front_domain`
+// and Host=<the real domain>. Kept conservative: anything on a separate CDN
+// (googlevideo, ytimg, doubleclick, etc.) is DROPPED because routing to the
+// wrong backend breaks rather than helps. Those fall through to the normal
+// MITM+relay path, where they'll work (slower) through Apps Script.
 const SNI_REWRITE_SUFFIXES: &[&str] = &[
     "youtube.com",
     "youtu.be",
     "youtube-nocookie.com",
-    "youtubeeducation.com",
-    "googlevideo.com",
-    "ytimg.com",
-    "ggpht.com",
-    "gvt1.com",
-    "gvt2.com",
-    "doubleclick.net",
-    "googlesyndication.com",
-    "googleadservices.com",
-    "google-analytics.com",
-    "googletagmanager.com",
-    "googletagservices.com",
     "fonts.googleapis.com",
 ];
 
@@ -229,6 +223,11 @@ fn parse_request_head(head: &[u8]) -> Option<(String, String, String, Vec<(Strin
     let method = parts.next()?.to_string();
     let target = parts.next()?.to_string();
     let version = parts.next().unwrap_or("HTTP/1.1").to_string();
+
+    if !is_valid_http_method(&method) {
+        return None;
+    }
+
     let mut headers = Vec::new();
     for l in lines {
         if l.is_empty() {
@@ -241,6 +240,21 @@ fn parse_request_head(head: &[u8]) -> Option<(String, String, String, Vec<(Strin
     Some((method, target, version, headers))
 }
 
+fn is_valid_http_method(m: &str) -> bool {
+    matches!(
+        m,
+        "GET"
+            | "POST"
+            | "PUT"
+            | "DELETE"
+            | "HEAD"
+            | "OPTIONS"
+            | "PATCH"
+            | "TRACE"
+            | "CONNECT"
+    )
+}
+
 // ---------- CONNECT handling ----------
 
 async fn do_connect(