cwtch/server/send/server_send_channel.go

100 lines
3.4 KiB
Go

package send
import (
"cwtch.im/cwtch/protocol"
"cwtch.im/cwtch/protocol/spam"
"errors"
"git.openprivacy.ca/openprivacy/libricochet-go/channels"
"git.openprivacy.ca/openprivacy/libricochet-go/wire/control"
"github.com/golang/protobuf/proto"
"log"
)
// CwtchServerSendChannel implements the ChannelHandler interface for a channel of
// type "im.cwtch.server.send - this implementation only handles server-side logic.
type CwtchServerSendChannel struct {
// Methods of Handler are called for Cwtch events on this channel
Handler CwtchServerSendChannelHandler
channel *channels.Channel
spamguard spam.Guard
}
// CwtchServerSendChannelHandler defines the interface needed to interact with this channel
type CwtchServerSendChannelHandler interface {
HandleGroupMessage(*protocol.GroupMessage)
}
// Type returns the type string for this channel, e.g. "im.ricochet.Cwtch".
func (cc *CwtchServerSendChannel) Type() string {
return "im.cwtch.server.send"
}
// Closed is called when the channel is closed for any reason.
func (cc *CwtchServerSendChannel) Closed(err error) {
}
// OnlyClientCanOpen - for Cwtch channels any side can open
func (cc *CwtchServerSendChannel) OnlyClientCanOpen() bool {
return true
}
// Singleton - for Cwtch channels there can only be one instance per direction
func (cc *CwtchServerSendChannel) Singleton() bool {
return true
}
// Bidirectional - for Cwtch channels are not bidrectional
func (cc *CwtchServerSendChannel) Bidirectional() bool {
return false
}
// RequiresAuthentication - Cwtch channels require hidden service auth
func (cc *CwtchServerSendChannel) RequiresAuthentication() string {
return "none"
}
// OpenInbound is the first method called for an inbound channel request.
// If an error is returned, the channel is rejected. If a RawMessage is
// returned, it will be sent as the ChannelResult message.
func (cc *CwtchServerSendChannel) OpenInbound(channel *channels.Channel, raw *Protocol_Data_Control.OpenChannel) ([]byte, error) {
cc.channel = channel
cc.spamguard.Difficulty = 2
return cc.spamguard.GenerateChallenge(channel.ID), nil
}
// OpenOutbound is the first method called for an outbound channel request.
// If an error is returned, the channel is not opened. If a RawMessage is
// returned, it will be sent as the OpenChannel message.
func (cc *CwtchServerSendChannel) OpenOutbound(channel *channels.Channel) ([]byte, error) {
return nil, errors.New("server does not open send channel")
}
// OpenOutboundResult is called when a response is received for an
// outbound OpenChannel request. If `err` is non-nil, the channel was
// rejected and Closed will be called immediately afterwards. `raw`
// contains the raw protocol message including any extension data.
func (cc *CwtchServerSendChannel) OpenOutboundResult(err error, crm *Protocol_Data_Control.ChannelResult) {
// NOTE: Should never be called
}
// Packet is called for each raw packet received on this channel.
func (cc *CwtchServerSendChannel) Packet(data []byte) {
csp := &protocol.CwtchServerPacket{}
err := proto.Unmarshal(data, csp)
if err == nil {
if csp.GetGroupMessage() != nil {
gm := csp.GetGroupMessage()
ok := cc.spamguard.ValidateChallenge(gm.GetCiphertext(), gm.GetSpamguard())
if ok {
cc.Handler.HandleGroupMessage(gm)
} else {
log.Printf("[ERROR] Failed to validate spamguard %v\n", gm)
}
}
} else {
log.Printf("[ERROR] Failed to decode packet on SEND channel %v\n", err)
}
cc.channel.CloseChannel()
}