dendrite/federationsender/internal/perform/join.go

106 lines
3.6 KiB
Go

package perform
import (
"context"
"fmt"
"github.com/matrix-org/gomatrixserverlib"
)
// This file contains helpers for the PerformJoin function.
type joinContext struct {
federation *gomatrixserverlib.FederationClient
keyRing *gomatrixserverlib.KeyRing
}
// Returns a new join context.
func JoinContext(f *gomatrixserverlib.FederationClient, k *gomatrixserverlib.KeyRing) *joinContext {
return &joinContext{
federation: f,
keyRing: k,
}
}
// checkSendJoinResponse checks that all of the signatures are correct
// and that the join is allowed by the supplied state.
func (r joinContext) CheckSendJoinResponse(
ctx context.Context,
event gomatrixserverlib.Event,
server gomatrixserverlib.ServerName,
respMakeJoin gomatrixserverlib.RespMakeJoin,
respSendJoin gomatrixserverlib.RespSendJoin,
) (*gomatrixserverlib.RespState, error) {
// A list of events that we have retried, if they were not included in
// the auth events supplied in the send_join.
retries := map[string][]gomatrixserverlib.Event{}
// Define a function which we can pass to Check to retrieve missing
// auth events inline. This greatly increases our chances of not having
// to repeat the entire set of checks just for a missing event or two.
missingAuth := func(roomVersion gomatrixserverlib.RoomVersion, eventIDs []string) ([]gomatrixserverlib.Event, error) {
returning := []gomatrixserverlib.Event{}
// See if we have retry entries for each of the supplied event IDs.
for _, eventID := range eventIDs {
// If we've already satisfied a request for this event ID before then
// just append the results. We won't retry the request.
if retry, ok := retries[eventID]; ok {
if retry == nil {
return nil, fmt.Errorf("missingAuth: not retrying failed event ID %q", eventID)
}
returning = append(returning, retry...)
continue
}
// Make a note of the fact that we tried to do something with this
// event ID, even if we don't succeed.
retries[event.EventID()] = nil
// Try to retrieve the event from the server that sent us the send
// join response.
tx, txerr := r.federation.GetEvent(ctx, server, eventID)
if txerr != nil {
return nil, fmt.Errorf("missingAuth r.federation.GetEvent: %w", txerr)
}
// For each event returned, add it to the set of return events. We
// also will populate the retries, in case someone asks for this
// event ID again.
for _, pdu := range tx.PDUs {
// Try to parse the event.
ev, everr := gomatrixserverlib.NewEventFromUntrustedJSON(pdu, roomVersion)
if everr != nil {
return nil, fmt.Errorf("missingAuth gomatrixserverlib.NewEventFromUntrustedJSON: %w", everr)
}
// Check the signatures of the event.
if res, err := gomatrixserverlib.VerifyEventSignatures(ctx, []gomatrixserverlib.Event{ev}, r.keyRing); err != nil {
return nil, fmt.Errorf("missingAuth VerifyEventSignatures: %w", err)
} else {
for _, err := range res {
if err != nil {
return nil, fmt.Errorf("missingAuth VerifyEventSignatures: %w", err)
}
}
}
// If the event is OK then add it to the results and the retry map.
returning = append(returning, ev)
retries[event.EventID()] = append(retries[event.EventID()], ev)
retries[ev.EventID()] = append(retries[ev.EventID()], ev)
}
}
return returning, nil
}
// TODO: Can we expand Check here to return a list of missing auth
// events rather than failing one at a time?
rs, err := respSendJoin.Check(ctx, r.keyRing, event, missingAuth)
if err != nil {
return nil, fmt.Errorf("respSendJoin: %w", err)
}
return rs, nil
}