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dendrite/roomserver/internal/perform_join.go

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package internal
import (
"context"
"errors"
"fmt"
"strings"
"time"
fsAPI "github.com/matrix-org/dendrite/federationsender/api"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/sirupsen/logrus"
)
// PerformJoin handles joining matrix rooms, including over federation by talking to the federationsender.
func (r *RoomserverInternalAPI) 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 *RoomserverInternalAPI) 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 *RoomserverInternalAPI) 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 *RoomserverInternalAPI) 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)
}
// First work out if this is in response to an existing invite
// from a federated server. If it is then we avoid the situation
// where we might think we know about a room in the following
// section but don't know the latest state as all of our users
// have left.
isInvitePending, inviteSender, _, err := r.isInvitePending(ctx, req.RoomIDOrAlias, req.UserID)
if err == nil && isInvitePending {
// Check if there's an invite pending.
_, inviterDomain, ierr := gomatrixserverlib.SplitID('@', inviteSender)
if ierr != nil {
return "", fmt.Errorf("gomatrixserverlib.SplitID: %w", err)
}
// Check that the domain isn't ours. If it's local then we don't
// need to do anything as our own copy of the room state will be
// up-to-date.
if inviterDomain != r.Cfg.Matrix.ServerName {
// Add the server of the person who invited us to the server list,
// as they should be a fairly good bet.
req.ServerNames = append(req.ServerNames, inviterDomain)
// Perform a federated room join.
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.
buildRes := api.QueryLatestEventsAndStateResponse{}
event, err := eventutil.BuildEvent(
ctx, // the request context
&eb, // the template join event
r.Cfg.Matrix, // the server configuration
time.Now(), // the event timestamp to use
r, // the roomserver API to use
&buildRes, // the query response
)
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 membership, merr := se.Membership(); merr == nil {
if se.StateKey() != nil && *se.StateKey() == *event.StateKey() {
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.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 *RoomserverInternalAPI) 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
}