feat(protocol): carry complete encoded media frames

tools/validate_frames.py

@@ -7,47 +7,58 @@ import binascii
 import pathlib
 
 ROOT = pathlib.Path(__file__).resolve().parents[1]
-HEADER_BYTES = 21
-MAX_FRAME_BYTES = 65536
-CHANNEL_LIMITS = {1: 1024, 2: 2048, 3: 65515, 10: 1179, 11: 1179, 12: 1179}
+V1_CHANNEL_LIMITS = {1: 1024, 2: 2048, 3: 65515, 10: 1179, 11: 1179, 12: 1179}
+V2_CHANNEL_LIMITS = {10: 1177, 11: 1177}
 
 
 def classify(raw: bytes) -> str:
-    if len(raw) < HEADER_BYTES:
+    if len(raw) < 3:
         return "invalid:truncated"
     if raw[:2] != b"VD":
         return "invalid:magic"
-    if raw[2] != 1:
+    if raw[2] not in (1, 2):
         return "invalid:unsupported_version"
-    if raw[3] not in CHANNEL_LIMITS:
+    header_bytes = 21 if raw[2] == 1 else 23
+    if len(raw) < header_bytes:
+        return "invalid:truncated"
+    limits = V1_CHANNEL_LIMITS if raw[2] == 1 else V2_CHANNEL_LIMITS
+    if raw[3] not in limits:
         return "invalid:unknown_channel"
     if raw[4] != 0:
         return "invalid:flags"
-    fragment_index, fragment_count = raw[17], raw[18]
+    if raw[2] == 1:
+        fragment_index, fragment_count = raw[17], raw[18]
+        payload_length = int.from_bytes(raw[19:21], "big")
+    else:
+        fragment_index = int.from_bytes(raw[17:19], "big")
+        fragment_count = int.from_bytes(raw[19:21], "big")
+        payload_length = int.from_bytes(raw[21:23], "big")
+        if fragment_count > 891:
+            return "invalid:fragment_limit"
     if fragment_count == 0 or fragment_index >= fragment_count:
         return "invalid:fragment"
-    payload_length = int.from_bytes(raw[19:21], "big")
-    if payload_length > CHANNEL_LIMITS[raw[3]]:
+    if payload_length > limits[raw[3]]:
         return "invalid:payload_limit"
-    if len(raw) != HEADER_BYTES + payload_length:
+    if len(raw) != header_bytes + payload_length:
         return "invalid:length_mismatch"
-    if len(raw) > MAX_FRAME_BYTES:
+    if raw[2] == 1 and len(raw) > 65536 or raw[2] == 2 and len(raw) > 1200:
         return "invalid:frame_limit"
     return "valid"
 
 
 def main() -> None:
-    lines = (ROOT / "fixtures/conformance/datagram-v1.tsv").read_text(encoding="utf-8").splitlines()
-    assert lines[0] == "id\tversion\tkind\tinput\texpected"
-    for line in lines[1:]:
-        identifier, version, kind, input_value, expected = line.split("\t")
-        assert kind == "datagram" and version == "1"
-        encoded = input_value.removeprefix("hex=")
-        try:
-            actual = classify(binascii.unhexlify(encoded))
-        except binascii.Error:
-            actual = "invalid:hex"
-        assert actual == expected, f"{identifier}: {actual} != {expected}"
+    for fixture in ("datagram-v1.tsv", "datagram-v2.tsv"):
+        lines = (ROOT / "fixtures/conformance" / fixture).read_text(encoding="utf-8").splitlines()
+        assert lines[0] == "id\tversion\tkind\tinput\texpected"
+        for line in lines[1:]:
+            identifier, version, kind, input_value, expected = line.split("\t")
+            assert kind == "datagram" and version in ("1", "2")
+            encoded = input_value.removeprefix("hex=")
+            try:
+                actual = classify(binascii.unhexlify(encoded))
+            except binascii.Error:
+                actual = "invalid:hex"
+            assert actual == expected, f"{fixture}:{identifier}: {actual} != {expected}"
     print("Datagram frame validation passed")