dendrite/roomserver/internal/perform/perform_join.go

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// Copyright 2020 The Matrix.org Foundation C.I.C.
//
// 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 perform
import (
"context"
"errors"
"fmt"
"strings"
"time"
fsAPI "github.com/matrix-org/dendrite/federationsender/api"
"github.com/matrix-org/dendrite/internal/config"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/internal/helpers"
"github.com/matrix-org/dendrite/roomserver/internal/input"
"github.com/matrix-org/dendrite/roomserver/storage"
"github.com/matrix-org/gomatrixserverlib"
"github.com/sirupsen/logrus"
)
type Joiner struct {
ServerName gomatrixserverlib.ServerName
Cfg *config.RoomServer
FSAPI fsAPI.FederationSenderInternalAPI
DB storage.Database
Inputer *input.Inputer
}
// PerformJoin handles joining matrix rooms, including over federation by talking to the federationsender.
func (r *Joiner) PerformJoin(
ctx context.Context,
req *api.PerformJoinRequest,
res *api.PerformJoinResponse,
) {
roomID, err := r.performJoin(ctx, req)
if err != nil {
perr, ok := err.(*api.PerformError)
if ok {
res.Error = perr
} else {
res.Error = &api.PerformError{
Msg: err.Error(),
}
}
}
res.RoomID = roomID
}
func (r *Joiner) performJoin(
ctx context.Context,
req *api.PerformJoinRequest,
) (string, error) {
_, domain, err := gomatrixserverlib.SplitID('@', req.UserID)
if err != nil {
return "", &api.PerformError{
Code: api.PerformErrorBadRequest,
Msg: fmt.Sprintf("Supplied user ID %q in incorrect format", req.UserID),
}
}
if domain != r.Cfg.Matrix.ServerName {
return "", &api.PerformError{
Code: api.PerformErrorBadRequest,
Msg: fmt.Sprintf("User %q does not belong to this homeserver", req.UserID),
}
}
if strings.HasPrefix(req.RoomIDOrAlias, "!") {
return r.performJoinRoomByID(ctx, req)
}
if strings.HasPrefix(req.RoomIDOrAlias, "#") {
return r.performJoinRoomByAlias(ctx, req)
}
return "", &api.PerformError{
Code: api.PerformErrorBadRequest,
Msg: fmt.Sprintf("Room ID or alias %q is invalid", req.RoomIDOrAlias),
}
}
func (r *Joiner) performJoinRoomByAlias(
ctx context.Context,
req *api.PerformJoinRequest,
) (string, error) {
// Get the domain part of the room alias.
_, domain, err := gomatrixserverlib.SplitID('#', req.RoomIDOrAlias)
if err != nil {
return "", fmt.Errorf("Alias %q is not in the correct format", req.RoomIDOrAlias)
}
req.ServerNames = append(req.ServerNames, domain)
// Check if this alias matches our own server configuration. If it
// doesn't then we'll need to try a federated join.
var roomID string
if domain != r.Cfg.Matrix.ServerName {
// The alias isn't owned by us, so we will need to try joining using
// a remote server.
dirReq := fsAPI.PerformDirectoryLookupRequest{
RoomAlias: req.RoomIDOrAlias, // the room alias to lookup
ServerName: domain, // the server to ask
}
dirRes := fsAPI.PerformDirectoryLookupResponse{}
err = r.FSAPI.PerformDirectoryLookup(ctx, &dirReq, &dirRes)
if err != nil {
logrus.WithError(err).Errorf("error looking up alias %q", req.RoomIDOrAlias)
return "", fmt.Errorf("Looking up alias %q over federation failed: %w", req.RoomIDOrAlias, err)
}
roomID = dirRes.RoomID
req.ServerNames = append(req.ServerNames, dirRes.ServerNames...)
} else {
// Otherwise, look up if we know this room alias locally.
roomID, err = r.DB.GetRoomIDForAlias(ctx, req.RoomIDOrAlias)
if err != nil {
return "", fmt.Errorf("Lookup room alias %q failed: %w", req.RoomIDOrAlias, err)
}
}
// If the room ID is empty then we failed to look up the alias.
if roomID == "" {
return "", fmt.Errorf("Alias %q not found", req.RoomIDOrAlias)
}
// If we do, then pluck out the room ID and continue the join.
req.RoomIDOrAlias = roomID
return r.performJoinRoomByID(ctx, req)
}
// TODO: Break this function up a bit
// nolint:gocyclo
func (r *Joiner) performJoinRoomByID(
ctx context.Context,
req *api.PerformJoinRequest,
) (string, error) {
// Get the domain part of the room ID.
_, domain, err := gomatrixserverlib.SplitID('!', req.RoomIDOrAlias)
if err != nil {
return "", &api.PerformError{
Code: api.PerformErrorBadRequest,
Msg: fmt.Sprintf("Room ID %q is invalid: %s", req.RoomIDOrAlias, err),
}
}
// If the server name in the room ID isn't ours then it's a
// possible candidate for finding the room via federation. Add
// it to the list of servers to try.
if domain != r.Cfg.Matrix.ServerName {
req.ServerNames = append(req.ServerNames, domain)
}
// Prepare the template for the join event.
userID := req.UserID
eb := gomatrixserverlib.EventBuilder{
Type: gomatrixserverlib.MRoomMember,
Sender: userID,
StateKey: &userID,
RoomID: req.RoomIDOrAlias,
Redacts: "",
}
if err = eb.SetUnsigned(struct{}{}); err != nil {
return "", fmt.Errorf("eb.SetUnsigned: %w", err)
}
// It is possible for the request to include some "content" for the
// event. We'll always overwrite the "membership" key, but the rest,
// like "display_name" or "avatar_url", will be kept if supplied.
if req.Content == nil {
req.Content = map[string]interface{}{}
}
req.Content["membership"] = gomatrixserverlib.Join
if err = eb.SetContent(req.Content); err != nil {
return "", fmt.Errorf("eb.SetContent: %w", err)
}
// Force a federated join if we aren't in the room and we've been
// given some server names to try joining by.
serverInRoom, _ := helpers.IsServerCurrentlyInRoom(ctx, r.DB, r.ServerName, req.RoomIDOrAlias)
forceFederatedJoin := len(req.ServerNames) > 0 && !serverInRoom
// Force a federated join if we're dealing with a pending invite
// and we aren't in the room.
isInvitePending, inviteSender, _, err := helpers.IsInvitePending(ctx, r.DB, req.RoomIDOrAlias, req.UserID)
if err == nil && isInvitePending {
_, inviterDomain, ierr := gomatrixserverlib.SplitID('@', inviteSender)
if ierr != nil {
return "", fmt.Errorf("gomatrixserverlib.SplitID: %w", err)
}
// If we were invited by someone from another server then we can
// assume they are in the room so we can join via them.
if inviterDomain != r.Cfg.Matrix.ServerName {
req.ServerNames = append(req.ServerNames, inviterDomain)
forceFederatedJoin = true
}
}
// If we should do a forced federated join then do that.
if forceFederatedJoin {
return req.RoomIDOrAlias, r.performFederatedJoinRoomByID(ctx, req)
}
// Try to construct an actual join event from the template.
// If this succeeds then it is a sign that the room already exists
// locally on the homeserver.
// TODO: Check what happens if the room exists on the server
// but everyone has since left. I suspect it does the wrong thing.
event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
switch err {
case nil:
// The room join is local. Send the new join event into the
// roomserver. First of all check that the user isn't already
// a member of the room.
alreadyJoined := false
for _, se := range buildRes.StateEvents {
if !se.StateKeyEquals(userID) {
continue
}
if membership, merr := se.Membership(); merr == nil {
alreadyJoined = (membership == gomatrixserverlib.Join)
break
}
}
// If we haven't already joined the room then send an event
// into the room changing our membership status.
if !alreadyJoined {
inputReq := api.InputRoomEventsRequest{
InputRoomEvents: []api.InputRoomEvent{
{
Kind: api.KindNew,
Event: event.Headered(buildRes.RoomVersion),
AuthEventIDs: event.AuthEventIDs(),
SendAsServer: string(r.Cfg.Matrix.ServerName),
},
},
}
inputRes := api.InputRoomEventsResponse{}
if err = r.Inputer.InputRoomEvents(ctx, &inputReq, &inputRes); err != nil {
var notAllowed *gomatrixserverlib.NotAllowed
if errors.As(err, &notAllowed) {
return "", &api.PerformError{
Code: api.PerformErrorNotAllowed,
Msg: fmt.Sprintf("InputRoomEvents auth failed: %s", err),
}
}
return "", fmt.Errorf("r.InputRoomEvents: %w", err)
}
}
case eventutil.ErrRoomNoExists:
// The room doesn't exist locally. If the room ID looks like it should
// be ours then this probably means that we've nuked our database at
// some point.
if domain == r.Cfg.Matrix.ServerName {
// If there are no more server names to try then give up here.
// Otherwise we'll try a federated join as normal, since it's quite
// possible that the room still exists on other servers.
if len(req.ServerNames) == 0 {
return "", &api.PerformError{
Code: api.PerformErrorNoRoom,
Msg: fmt.Sprintf("Room ID %q does not exist", req.RoomIDOrAlias),
}
}
}
// Perform a federated room join.
return req.RoomIDOrAlias, r.performFederatedJoinRoomByID(ctx, req)
default:
// Something else went wrong.
return "", fmt.Errorf("Error joining local room: %q", err)
}
// By this point, if req.RoomIDOrAlias contained an alias, then
// it will have been overwritten with a room ID by performJoinRoomByAlias.
// We should now include this in the response so that the CS API can
// return the right room ID.
return req.RoomIDOrAlias, nil
}
func (r *Joiner) performFederatedJoinRoomByID(
ctx context.Context,
req *api.PerformJoinRequest,
) error {
// Try joining by all of the supplied server names.
fedReq := fsAPI.PerformJoinRequest{
RoomID: req.RoomIDOrAlias, // the room ID to try and join
UserID: req.UserID, // the user ID joining the room
ServerNames: req.ServerNames, // the server to try joining with
Content: req.Content, // the membership event content
}
fedRes := fsAPI.PerformJoinResponse{}
r.FSAPI.PerformJoin(ctx, &fedReq, &fedRes)
if fedRes.LastError != nil {
return &api.PerformError{
Code: api.PerformErrRemote,
Msg: fedRes.LastError.Message,
RemoteCode: fedRes.LastError.Code,
}
}
return nil
}
func buildEvent(
ctx context.Context, db storage.Database, cfg *config.Global, builder *gomatrixserverlib.EventBuilder,
) (*gomatrixserverlib.HeaderedEvent, *api.QueryLatestEventsAndStateResponse, error) {
eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
if err != nil {
return nil, nil, fmt.Errorf("gomatrixserverlib.StateNeededForEventBuilder: %w", err)
}
if len(eventsNeeded.Tuples()) == 0 {
return nil, nil, errors.New("expecting state tuples for event builder, got none")
}
var queryRes api.QueryLatestEventsAndStateResponse
err = helpers.QueryLatestEventsAndState(ctx, db, &api.QueryLatestEventsAndStateRequest{
RoomID: builder.RoomID,
StateToFetch: eventsNeeded.Tuples(),
}, &queryRes)
if err != nil {
return nil, nil, fmt.Errorf("QueryLatestEventsAndState: %w", err)
}
ev, err := eventutil.BuildEvent(ctx, builder, cfg, time.Now(), &eventsNeeded, &queryRes)
if err != nil {
return nil, nil, err
}
return ev, &queryRes, nil
}