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"""Which handler answers which MNP message, and the guards that come before any
of them."""
import logging
from meshbay_common.protocol import MNP
log = logging.getLogger("meshbay_node.transport.webrtc_server")
# Bundle fetches are served in the pre-proof window (C4). Bounded and audited
# until the native client removes remote keypair bundles entirely.
MAX_PRE_PROOF_FETCHES = 4
# After the handshake: which method answers each message type, and whether it
# runs as a task of this session (`_spawn`) or before the next message is read.
# That choice is made per type, deliberately; the golden master in the tests
# records it for every type.
SPAWNED, INLINE = True, False
_HANDLERS = {
MNP.INDEX_SYNC: ("_do_index_sync", INLINE),
# Spawned rather than answered inline: the reply waits for room
# on the channel, and blocking the message loop for that would
# stop everything else this peer is doing — including the
# uploads whose acks free the very buffer we are waiting on.
# Chunks are matched by file and index on the client, so
# answering out of order is safe.
MNP.FILE_REQUEST: ("_do_file_request", SPAWNED),
MNP.CHAT_MESSAGE: ("_do_chat_message", INLINE),
MNP.CHAT_HISTORY: ("_do_chat_history", INLINE),
MNP.LINK_PREVIEW_REQ: ("_do_link_preview_request", SPAWNED),
MNP.PING: ("_do_ping", INLINE),
MNP.TRANSFER_OPEN: ("_do_transfer_open", INLINE),
MNP.TRANSFER_CLOSE: ("_do_transfer_close", INLINE),
MNP.FILE_UPLOAD: ("_do_file_upload", SPAWNED),
MNP.DIR_CREATE: ("_do_dir_create", SPAWNED),
MNP.DIR_DELETE: ("_do_dir_delete", SPAWNED),
MNP.FILE_DELETE: ("_do_file_delete", INLINE),
MNP.ADMIN_RESPONSE: ("_do_admin_response", INLINE),
MNP.INVITE_CREATE: ("_do_invite_create", INLINE),
MNP.INVITE_LINK_CREATE: ("_do_invite_link_create", INLINE),
MNP.INVITE_CANCEL: ("_do_invite_cancel", INLINE),
MNP.MEMBER_REVOKE: ("_do_member_revoke", INLINE),
MNP.DEVICE_REQUEST: ("_do_device_request", SPAWNED),
MNP.DEVICE_LOOKUP: ("_do_device_lookup", SPAWNED),
MNP.DEVICE_ADD: ("_do_device_add", SPAWNED),
MNP.DEVICE_LIST: ("_do_device_list", SPAWNED),
MNP.DEVICE_REVOKE: ("_do_device_revoke", SPAWNED),
MNP.DEVICE_HELLO: ("_do_device_hello", SPAWNED),
MNP.APPS_ENABLED: ("_do_apps_enabled", INLINE),
MNP.TRANSFER_LIMITS: ("_do_transfer_limits", INLINE),
MNP.SET_SCAN_SETTINGS: ("_do_set_scan_settings", INLINE),
MNP.TMDB_CONFIG: ("_do_tmdb_config", INLINE),
MNP.TMDB_ENABLED: ("_do_tmdb_enabled", INLINE),
MNP.APP_DIRECTORIES: ("_do_app_directories", INLINE),
MNP.CHAT_DIRECTORY: ("_do_chat_directory", INLINE),
MNP.CHAT_LINK_PREVIEW: ("_do_chat_link_preview", INLINE),
MNP.SEARCH_LISTED: ("_do_search_listed", INLINE),
MNP.CHAT_EPOCH: ("_do_chat_epoch", INLINE),
MNP.CHAT_KEYS_REQ: ("_do_chat_keys_req", SPAWNED),
MNP.GROUP_ROSTER_REQ: ("_do_group_roster_req", SPAWNED),
MNP.MEDIA_META_REQ: ("_do_media_meta_request", SPAWNED),
MNP.SEASON_META_REQ: ("_do_season_meta_request", SPAWNED),
MNP.TMDB_SEARCH_REQ: ("_do_tmdb_search_request", SPAWNED),
MNP.TMDB_OVERRIDE: ("_do_tmdb_override", INLINE),
MNP.TMDB_REMATCH: ("_do_tmdb_rematch", INLINE),
MNP.MUSICBRAINZ_ENABLED: ("_do_musicbrainz_enabled", INLINE),
MNP.MUSIC_META_REQ: ("_do_music_meta_request", SPAWNED),
MNP.AUDIO_TRANSCODE_REQ: ("_do_audio_transcode_request", SPAWNED),
MNP.SUBTITLE_REQ: ("_do_subtitle_request", SPAWNED),
MNP.MEMBER_UNPIN: ("_do_member_unpin", INLINE),
MNP.GEK_ROTATE: ("_do_gek_rotate", INLINE),
MNP.NODE_STATUS: ("_do_node_status", SPAWNED),
MNP.ROOT_ADD: ("_do_root_add", INLINE),
MNP.ROOT_REMOVE: ("_do_root_remove", INLINE),
MNP.ROOT_UPDATE: ("_do_root_update", INLINE),
MNP.ROOT_EJECT: ("_do_root_eject", INLINE),
MNP.ROOT_PLUG: ("_do_root_plug", INLINE),
MNP.ROSTER_READ: ("_do_roster_read", SPAWNED),
MNP.DENYLIST_READ: ("_do_denylist_read", SPAWNED),
MNP.DENYLIST_CLEAR: ("_do_denylist_clear", SPAWNED),
MNP.GROUP_ATTACH: ("_do_group_attach", INLINE),
MNP.GROUP_DETACH: ("_do_group_detach", INLINE),
MNP.NODE_SETTINGS_SET: ("_do_node_settings_set", SPAWNED),
MNP.NODE_RELOAD: ("_do_node_reload", SPAWNED),
MNP.KEYPAIR_BUNDLE_STORE: ("_do_keypair_bundle_store", SPAWNED),
MNP.KEYPAIR_BUNDLE_DELETE: ("_do_keypair_bundle_delete", SPAWNED),
MNP.USER_BLOB_STORE: ("_do_user_blob_store", SPAWNED),
MNP.USER_BLOB_FETCH: ("_do_user_blob_fetch", SPAWNED),
MNP.USER_BLOB_LIST: ("_do_user_blob_list", SPAWNED),
MNP.USER_BLOB_DELETE: ("_do_user_blob_delete", SPAWNED),
MNP.STREAM_REQUEST: ("_do_stream_request", INLINE),
MNP.STREAM_MORE: ("_grant_stream_credit", INLINE),
'client_diag': ("_do_client_diag", INLINE),
MNP.STREAM_STOP: ("_do_stream_stop", INLINE),
}
# The handlers that are called without the message.
_TAKES_NO_MESSAGE = frozenset({
"_do_index_sync",
"_do_keypair_bundle_delete",
"_do_stream_stop",
"_do_user_blob_list",
})
class DispatchMixin:
def _dispatch_message(self, msg: dict) -> None:
mtype = msg.get("type")
log.debug("WebRTC recv: %s", mtype)
try:
if mtype == MNP.HANDSHAKE:
self._do_handshake(msg)
elif mtype == MNP.HANDSHAKE_RESPONSE:
self._do_handshake_response(msg)
elif mtype in (MNP.GEK_BUNDLE_FETCH, MNP.KEYPAIR_BUNDLE_FETCH) \
and self._gek_challenge is not None:
# Served before the GEK proof by necessity: the client needs its
# wrapped bundle in order to compute the proof. That window is a
# disclosure surface (C4) — a hub that forges a JWT reaches it — so
# it is bounded and audited here, and closed properly when clients
# stop storing keypair bundles on other people's nodes.
self._pre_proof_fetches += 1
if self._pre_proof_fetches > MAX_PRE_PROOF_FETCHES:
self._audit_auth_failed(
getattr(self, "_pending_group", ""), "pre-proof fetch flood")
self._send({"type": "error", "detail": "Too many requests"})
return
self._audit_pre_proof_fetch(mtype)
if mtype == MNP.GEK_BUNDLE_FETCH:
self._spawn(self._do_gek_bundle_fetch())
else:
self._spawn(self._do_keypair_bundle_fetch())
elif mtype == MNP.JOIN_REQUEST and self._nonce_node:
# Valid both before the GEK proof (a new member has no GEK to prove
# with) and after it (an operator pairing a browser is already
# connected). Authority comes from the pairing code and the
# signature, never from the session state.
self._spawn(self._do_join_request(msg))
elif self._user_id is None:
self._send({"type": "error", "detail": "Handshake required"})
else:
try:
entry = _HANDLERS.get(mtype)
except TypeError:
# A list or a map is a legal msgpack value for `type` and not a
# key: it names no handler, as it matched no comparison before.
entry = None
if entry is None:
log.warning("Unknown MNP message type on DataChannel: %s", mtype)
else:
name, spawned = entry
method = getattr(self, name)
result = method() if name in _TAKES_NO_MESSAGE else method(msg)
if spawned:
self._spawn(result)
except Exception as e:
# Log the detail locally; send the peer a generic message. Exception
# text here carries filesystem paths and internal state (finding L3).
log.error("Error handling %s on DataChannel: %s", mtype, e, exc_info=True)
self._send({"type": "error", "detail": "Request failed"})
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