feat(protocol): carry complete encoded media frames

tools/native_conformance.rs

@@ -189,36 +189,50 @@ fn classify_datagram(encoded: &str) -> &'static str {
         Some(raw) => raw,
         None => return "invalid:hex",
     };
-    if raw.len() < 21 {
+    if raw.len() < 3 {
         return "invalid:truncated";
     }
     if raw[0..2] != *b"VD" {
         return "invalid:magic";
     }
-    if raw[2] != 1 {
+    if raw[2] != 1 && raw[2] != 2 {
         return "invalid:unsupported_version";
     }
-    let limit = match raw[3] {
-        1 => 1024,
-        2 => 2048,
-        3 => 65515,
-        10 | 11 | 12 => 1179,
+    let header_bytes = if raw[2] == 1 { 21 } else { 23 };
+    if raw.len() < header_bytes {
+        return "invalid:truncated";
+    }
+    let limit = match (raw[2], raw[3]) {
+        (1, 1) => 1024,
+        (1, 2) => 2048,
+        (1, 3) => 65515,
+        (1, 10 | 11 | 12) => 1179,
+        (2, 10 | 11) => 1177,
         _ => return "invalid:unknown_channel",
     };
     if raw[4] != 0 {
         return "invalid:flags";
     }
-    if raw[18] == 0 || raw[17] >= raw[18] {
+    let (fragment_index, fragment_count, payload_offset) = if raw[2] == 1 {
+        (raw[17] as usize, raw[18] as usize, 19)
+    } else {
+        let count = ((raw[19] as usize) << 8) | raw[20] as usize;
+        if count > 891 {
+            return "invalid:fragment_limit";
+        }
+        ((((raw[17] as usize) << 8) | raw[18] as usize), count, 21)
+    };
+    if fragment_count == 0 || fragment_index >= fragment_count {
         return "invalid:fragment";
     }
-    let payload_length = ((raw[19] as usize) << 8) | raw[20] as usize;
+    let payload_length = ((raw[payload_offset] as usize) << 8) | raw[payload_offset + 1] as usize;
     if payload_length > limit {
         return "invalid:payload_limit";
     }
-    if raw.len() != 21 + payload_length {
+    if raw.len() != header_bytes + payload_length {
         return "invalid:length_mismatch";
     }
-    if raw.len() > 65536 {
+    if raw[2] == 1 && raw.len() > 65536 || raw[2] == 2 && raw.len() > 1200 {
         return "invalid:frame_limit";
     }
     "valid"