feat(protocol): define gateway control envelopes

tools/native_conformance.rs

@@ -53,10 +53,119 @@ fn evaluate(kind: &str, input: &str) -> &'static str {
         }
         "tunnel" => "invalid:unsupported_version",
         "datagram" => classify_datagram(values.get("hex").map(String::as_str).unwrap_or_default()),
+        "gateway_input" => classify_gateway_input(values.get("hex").map(String::as_str).unwrap_or_default()),
+        "gateway_feedback" => classify_gateway_feedback(values.get("hex").map(String::as_str).unwrap_or_default()),
+        "gateway_clipboard" if values.contains_key("file") => "invalid:forbidden",
+        "gateway_clipboard"
+            if matches!(values.get("direction").map(String::as_str), Some("client_to_provider") | Some("provider_to_client"))
+                && values.get("encoding").map(String::as_str) == Some("utf-8")
+                && values.get("loop_token").map_or(false, |value| (16..=128).contains(&value.len()))
+                && values.get("text").map_or(false, |value| value.len() <= 65536) => "valid",
+        "gateway_clipboard" => "invalid:clipboard",
+        "gateway_clipboard_audit" if values.contains_key("text") => "invalid:forbidden",
+        "gateway_clipboard_audit"
+            if matches!(values.get("direction").map(String::as_str), Some("client_to_provider") | Some("provider_to_client"))
+                && matches!(values.get("outcome").map(String::as_str), Some("forwarded") | Some("suppressed") | Some("rejected"))
+                && matches!(values.get("reason").map(String::as_str), Some("forwarded") | Some("loop") | Some("policy") | Some("rate") | Some("provider") | Some("malformed"))
+                && values.get("text_bytes").and_then(|value| value.parse::<usize>().ok()).map_or(false, |size| size <= 65536) => "valid",
+        "gateway_clipboard_audit" => "invalid:clipboard_audit",
         _ => "invalid:unknown_kind",
     }
 }
 
+fn classify_gateway_input(encoded: &str) -> &'static str {
+    let raw = match decode_hex(encoded) {
+        Some(raw) => raw,
+        None => return "invalid:hex",
+    };
+    if raw.len() < 6 {
+        return "invalid:truncated";
+    }
+    if raw[0..4] != *b"VGI1" {
+        return "invalid:magic";
+    }
+    let kind = raw[4];
+    let body = &raw[6..];
+    if body.len() != raw[5] as usize {
+        return "invalid:length";
+    }
+    match kind {
+        1 if body.len() == 4 && body[0] <= 1 && (body[2] != 0 || body[3] != 0) => "valid",
+        1 => "invalid:field",
+        2 if body.len() != 3 => "invalid:length",
+        2 if body[0] > 1 || !(1..=5).contains(&body[1]) => "invalid:field",
+        2 if body[2] != 0 => "invalid:reserved",
+        2 => "valid",
+        3 if body.len() == 4 => "valid",
+        3 => "invalid:length",
+        4 if (1..=4).contains(&body.len()) && std::str::from_utf8(body).ok().map_or(false, |value| value.chars().count() == 1) => "valid",
+        4 => "invalid:utf8",
+        5 if body.len() != 17 => "invalid:length",
+        5 if body[0] > 15 => "invalid:field",
+        5 if body[1] == 0 && body[2] == 0 && body[3..].iter().any(|value| *value != 0) => "invalid:field",
+        5 => "valid",
+        _ => "invalid:kind",
+    }
+}
+
+fn classify_gateway_feedback(encoded: &str) -> &'static str {
+    let raw = match decode_hex(encoded) {
+        Some(raw) => raw,
+        None => return "invalid:hex",
+    };
+    if raw.len() < 8 {
+        return "invalid:truncated";
+    }
+    if raw[0..4] != *b"VGF1" {
+        return "invalid:magic";
+    }
+    let direction = raw[4];
+    let kind = raw[5];
+    let body = &raw[8..];
+    if body.len() != ((raw[6] as usize) << 8 | raw[7] as usize) {
+        return "invalid:length";
+    }
+    if direction > 1 {
+        return "invalid:direction";
+    }
+    if direction == 0 {
+        if (0x10..=0x12).contains(&kind) {
+            return "invalid:direction";
+        }
+        return match kind {
+            1 if body.is_empty() => "valid",
+            1 => "invalid:length",
+            2 if valid_fec_status(body) => "valid",
+            2 => "invalid:field",
+            _ => "invalid:type",
+        };
+    }
+    if kind == 1 || kind == 2 {
+        return "invalid:direction";
+    }
+    match kind {
+        0x10 if body.len() == 4 => "valid",
+        0x10 => "invalid:length",
+        0x11 if body.len() != 5 => "invalid:length",
+        0x11 if body[0] <= 15 => "valid",
+        0x11 => "invalid:field",
+        0x12 if body.len() != 1 => "invalid:length",
+        0x12 if body[0] <= 1 => "valid",
+        0x12 => "invalid:field",
+        _ => "invalid:type",
+    }
+}
+
+fn valid_fec_status(body: &[u8]) -> bool {
+    body.len() == 21
+        && ((body[10] as u16) << 8 | body[11] as u16) > 0
+        && ((body[14] as u16) << 8 | body[15] as u16) <= ((body[10] as u16) << 8 | body[11] as u16)
+        && ((body[16] as u16) << 8 | body[17] as u16) <= ((body[12] as u16) << 8 | body[13] as u16)
+        && body[18] <= 100
+        && body[20] > 0
+        && body[19] < body[20]
+}
+
 fn decode_hex(input: &str) -> Option<Vec<u8>> {
     if input.len() % 2 != 0 {
         return None;