cwtch/client/send/peer_send_channel.go

package listen

import (
	"errors"
	"git.mascherari.press/cwtch/protocol"
	"git.mascherari.press/cwtch/protocol/spam"
	"github.com/golang/protobuf/proto"
	"github.com/s-rah/go-ricochet/channels"
	"github.com/s-rah/go-ricochet/utils"
	"github.com/s-rah/go-ricochet/wire/control"
)

// CwtchChannel implements the ChannelHandler interface for a channel of
// type "im.ricochet.Cwtch". The channel may be inbound or outbound.
//
// CwtchChannel implements protocol-level sanity and state validation, but
// does not handle or acknowledge Cwtch messages. The application must provide
// a CwtchChannelHandler implementation to handle Cwtch events.
type CwtchPeerSendChannel struct {
	channel *channels.Channel
	spamGuard spam.SpamGuard
	challenge []byte
}

// Type returns the type string for this channel, e.g. "im.ricochet.Cwtch".
func (cc *CwtchPeerSendChannel) Type() string {
	return "im.cwtch.server.send"
}

// Closed is called when the channel is closed for any reason.
func (cc *CwtchPeerSendChannel) Closed(err error) {

}

// OnlyClientCanOpen  - for Cwtch channels any side can open
func (cc *CwtchPeerSendChannel) OnlyClientCanOpen() bool {
	return true
}

// Singleton - for Cwtch channels there can only be one instance per direction
func (cc *CwtchPeerSendChannel) Singleton() bool {
	return true
}

// Bidirectional - for Cwtch channels are not bidrectional
func (cc *CwtchPeerSendChannel) Bidirectional() bool {
	return false
}

// RequiresAuthentication - Cwtch channels require hidden service auth
func (cc *CwtchPeerSendChannel) 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 *CwtchPeerSendChannel) OpenInbound(channel *channels.Channel, raw *Protocol_Data_Control.OpenChannel) ([]byte, error) {
	return nil, errors.New("client does not receive inbound listen channels")
}

// 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 (cplc *CwtchPeerSendChannel) OpenOutbound(channel *channels.Channel) ([]byte, error) {
        cplc.spamGuard.Difficulty = 2
	cplc.channel = channel
	messageBuilder := new(utils.MessageBuilder)
	return messageBuilder.OpenChannel(channel.ID, cplc.Type()), nil
}

// 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 (cplc *CwtchPeerSendChannel) OpenOutboundResult(err error, crm *Protocol_Data_Control.ChannelResult) {
	if err == nil {
		if crm.GetOpened() {
			cplc.channel.Pending = false
			ce, _ := proto.GetExtension(crm, protocol.E_ServerNonce)
		        cplc.challenge = ce.([]byte)[:]
		}
	}
}


// SendGroupMessage
func (cplc *CwtchPeerSendChannel) SendGroupMessage(gm *protocol.GroupMessage) {
        sgsolve := cplc.spamGuard.SolveChallenge(cplc.challenge, gm.GetCiphertext())
        gm.Spamguard = sgsolve
	csp := &protocol.CwtchServerPacket{
		GroupMessage: gm,
	}
	packet, _ := proto.Marshal(csp)
	cplc.channel.SendMessage(packet)
}

// Packet is called for each raw packet received on this channel.
func (cc *CwtchPeerSendChannel) Packet(data []byte) {
	// If we receive a packet on this channel, close the connection
	cc.channel.CloseChannel()
}