dendrite/federationapi/routing/send.go

334 lines
12 KiB
Go

// Copyright 2017 Vector Creations Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package routing
import (
"context"
"encoding/json"
"fmt"
"net/http"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
"github.com/matrix-org/dendrite/clientapi/producers"
"github.com/matrix-org/dendrite/common/config"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
// Send implements /_matrix/federation/v1/send/{txnID}
func Send(
httpReq *http.Request,
request *gomatrixserverlib.FederationRequest,
txnID gomatrixserverlib.TransactionID,
cfg *config.Dendrite,
query api.RoomserverQueryAPI,
producer *producers.RoomserverProducer,
eduProducer *producers.EDUServerProducer,
keys gomatrixserverlib.KeyRing,
federation *gomatrixserverlib.FederationClient,
) util.JSONResponse {
t := txnReq{
context: httpReq.Context(),
query: query,
producer: producer,
eduProducer: eduProducer,
keys: keys,
federation: federation,
}
var txnEvents struct {
PDUs []json.RawMessage `json:"pdus"`
EDUs []gomatrixserverlib.EDU `json:"edus"`
}
if err := json.Unmarshal(request.Content(), &txnEvents); err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
}
}
// TODO: Really we should have a function to convert FederationRequest to txnReq
t.PDUs = txnEvents.PDUs
t.EDUs = txnEvents.EDUs
t.Origin = request.Origin()
t.TransactionID = txnID
t.Destination = cfg.Matrix.ServerName
util.GetLogger(httpReq.Context()).Infof("Received transaction %q containing %d PDUs, %d EDUs", txnID, len(t.PDUs), len(t.EDUs))
resp, err := t.processTransaction()
switch err.(type) {
// No error? Great! Send back a 200.
case nil:
return util.JSONResponse{
Code: http.StatusOK,
JSON: resp,
}
// Handle known error cases as we will return a 400 error for these.
case roomNotFoundError:
case unmarshalError:
case verifySigError:
// Handle unknown error cases. Sending 500 errors back should be a last
// resort as this can make other homeservers back off sending federation
// events.
default:
util.GetLogger(httpReq.Context()).WithError(err).Error("t.processTransaction failed")
return jsonerror.InternalServerError()
}
// Return a 400 error for bad requests as fallen through from above.
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(err.Error()),
}
}
type txnReq struct {
gomatrixserverlib.Transaction
context context.Context
query api.RoomserverQueryAPI
producer *producers.RoomserverProducer
eduProducer *producers.EDUServerProducer
keys gomatrixserverlib.KeyRing
federation *gomatrixserverlib.FederationClient
}
func (t *txnReq) processTransaction() (*gomatrixserverlib.RespSend, error) {
results := make(map[string]gomatrixserverlib.PDUResult)
var pdus []gomatrixserverlib.HeaderedEvent
for _, pdu := range t.PDUs {
var header struct {
RoomID string `json:"room_id"`
}
if err := json.Unmarshal(pdu, &header); err != nil {
util.GetLogger(t.context).WithError(err).Warn("Transaction: Failed to extract room ID from event")
return nil, unmarshalError{err}
}
verReq := api.QueryRoomVersionForRoomRequest{RoomID: header.RoomID}
verRes := api.QueryRoomVersionForRoomResponse{}
if err := t.query.QueryRoomVersionForRoom(t.context, &verReq, &verRes); err != nil {
util.GetLogger(t.context).WithError(err).Warn("Transaction: Failed to query room version for room", verReq.RoomID)
return nil, roomNotFoundError{verReq.RoomID}
}
event, err := gomatrixserverlib.NewEventFromUntrustedJSON(pdu, verRes.RoomVersion)
if err != nil {
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Failed to parse event JSON of event %q", event.EventID())
return nil, unmarshalError{err}
}
if err := gomatrixserverlib.VerifyAllEventSignatures(t.context, []gomatrixserverlib.Event{event}, t.keys); err != nil {
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
return nil, verifySigError{event.EventID(), err}
}
pdus = append(pdus, event.Headered(verRes.RoomVersion))
}
// Process the events.
for _, e := range pdus {
err := t.processEvent(e.Unwrap())
if err != nil {
// If the error is due to the event itself being bad then we skip
// it and move onto the next event. We report an error so that the
// sender knows that we have skipped processing it.
//
// However if the event is due to a temporary failure in our server
// such as a database being unavailable then we should bail, and
// hope that the sender will retry when we are feeling better.
//
// It is uncertain what we should do if an event fails because
// we failed to fetch more information from the sending server.
// For example if a request to /state fails.
// If we skip the event then we risk missing the event until we
// receive another event referencing it.
// If we bail and stop processing then we risk wedging incoming
// transactions from that server forever.
switch err.(type) {
case roomNotFoundError:
case *gomatrixserverlib.NotAllowed:
default:
// Any other error should be the result of a temporary error in
// our server so we should bail processing the transaction entirely.
return nil, err
}
results[e.EventID()] = gomatrixserverlib.PDUResult{
Error: err.Error(),
}
util.GetLogger(t.context).WithError(err).WithField("event_id", e.EventID()).Warn("Failed to process incoming federation event, skipping it.")
} else {
results[e.EventID()] = gomatrixserverlib.PDUResult{}
}
}
t.processEDUs(t.EDUs)
util.GetLogger(t.context).Infof("Processed %d PDUs from transaction %q", len(results), t.TransactionID)
return &gomatrixserverlib.RespSend{PDUs: results}, nil
}
type roomNotFoundError struct {
roomID string
}
type unmarshalError struct {
err error
}
type verifySigError struct {
eventID string
err error
}
func (e roomNotFoundError) Error() string { return fmt.Sprintf("room %q not found", e.roomID) }
func (e unmarshalError) Error() string { return fmt.Sprintf("unable to parse event: %s", e.err) }
func (e verifySigError) Error() string {
return fmt.Sprintf("unable to verify signature of event %q: %s", e.eventID, e.err)
}
func (t *txnReq) processEDUs(edus []gomatrixserverlib.EDU) {
for _, e := range edus {
switch e.Type {
case gomatrixserverlib.MTyping:
// https://matrix.org/docs/spec/server_server/latest#typing-notifications
var typingPayload struct {
RoomID string `json:"room_id"`
UserID string `json:"user_id"`
Typing bool `json:"typing"`
}
if err := json.Unmarshal(e.Content, &typingPayload); err != nil {
util.GetLogger(t.context).WithError(err).Error("Failed to unmarshal typing event")
continue
}
if err := t.eduProducer.SendTyping(t.context, typingPayload.UserID, typingPayload.RoomID, typingPayload.Typing, 30*1000); err != nil {
util.GetLogger(t.context).WithError(err).Error("Failed to send typing event to edu server")
}
default:
util.GetLogger(t.context).WithField("type", e.Type).Warn("unhandled edu")
}
}
}
func (t *txnReq) processEvent(e gomatrixserverlib.Event) error {
prevEventIDs := e.PrevEventIDs()
// Fetch the state needed to authenticate the event.
needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{e})
stateReq := api.QueryStateAfterEventsRequest{
RoomID: e.RoomID(),
PrevEventIDs: prevEventIDs,
StateToFetch: needed.Tuples(),
}
var stateResp api.QueryStateAfterEventsResponse
if err := t.query.QueryStateAfterEvents(t.context, &stateReq, &stateResp); err != nil {
return err
}
if !stateResp.RoomExists {
// TODO: When synapse receives a message for a room it is not in it
// asks the remote server for the state of the room so that it can
// check if the remote server knows of a join "m.room.member" event
// that this server is unaware of.
// However generally speaking we should reject events for rooms we
// aren't a member of.
return roomNotFoundError{e.RoomID()}
}
if !stateResp.PrevEventsExist {
return t.processEventWithMissingState(e, stateResp.RoomVersion)
}
// Check that the event is allowed by the state at the event.
var events []gomatrixserverlib.Event
for _, headeredEvent := range stateResp.StateEvents {
events = append(events, headeredEvent.Unwrap())
}
if err := checkAllowedByState(e, events); err != nil {
return err
}
// TODO: Check that the roomserver has a copy of all of the auth_events.
// TODO: Check that the event is allowed by its auth_events.
// pass the event to the roomserver
_, err := t.producer.SendEvents(
t.context,
[]gomatrixserverlib.HeaderedEvent{
e.Headered(stateResp.RoomVersion),
},
api.DoNotSendToOtherServers,
nil,
)
return err
}
func checkAllowedByState(e gomatrixserverlib.Event, stateEvents []gomatrixserverlib.Event) error {
authUsingState := gomatrixserverlib.NewAuthEvents(nil)
for i := range stateEvents {
err := authUsingState.AddEvent(&stateEvents[i])
if err != nil {
return err
}
}
return gomatrixserverlib.Allowed(e, &authUsingState)
}
func (t *txnReq) processEventWithMissingState(e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion) error {
// We are missing the previous events for this events.
// This means that there is a gap in our view of the history of the
// room. There two ways that we can handle such a gap:
// 1) We can fill in the gap using /get_missing_events
// 2) We can leave the gap and request the state of the room at
// this event from the remote server using either /state_ids
// or /state.
// Synapse will attempt to do 1 and if that fails or if the gap is
// too large then it will attempt 2.
// Synapse will use /state_ids if possible since usually the state
// is largely unchanged and it is more efficient to fetch a list of
// event ids and then use /event to fetch the individual events.
// However not all version of synapse support /state_ids so you may
// need to fallback to /state.
// TODO: Attempt to fill in the gap using /get_missing_events
// TODO: Attempt to fetch the state using /state_ids and /events
state, err := t.federation.LookupState(t.context, t.Origin, e.RoomID(), e.EventID(), roomVersion)
if err != nil {
return err
}
// Check that the returned state is valid.
if err := state.Check(t.context, t.keys); err != nil {
return err
}
// Check that the event is allowed by the state.
retryAllowedState:
if err := checkAllowedByState(e, state.StateEvents); err != nil {
switch missing := err.(type) {
case gomatrixserverlib.MissingAuthEventError:
// An auth event was missing so let's look up that event over federation
for _, s := range state.StateEvents {
if s.EventID() != missing.AuthEventID {
continue
}
err = t.processEventWithMissingState(s, roomVersion)
// If there was no error retrieving the event from federation then
// we assume that it succeeded, so retry the original state check
if err == nil {
goto retryAllowedState
}
}
default:
}
return err
}
// pass the event along with the state to the roomserver
return t.producer.SendEventWithState(t.context, state, e.Headered(roomVersion))
}