Implement inbound contact request protocol

This implements a handler for inbound contact request connections,
taking advantage of the synchronous Process API.

This is largely untested code at the moment.

core/contactlist.go

@@ -298,7 +298,8 @@ func (cl *ContactList) RemoveInboundContactRequest(request *InboundContactReques
 		return errors.New("Request is not in contact list")
 	}
 
-	request.CloseConnection()
+	// Close connection asynchronously to avoid potential deadlocking
+	go request.CloseConnection()
 	// XXX Remove from config
 
 	delete(cl.inboundRequests, requestData.Address)

core/identity.go

@@ -197,9 +197,12 @@ func (me *Identity) handleInboundConnection(conn net.Conn) error {
 		return nil
 	}
 
-	// XXX-protocol Unknown contact, should pass to handler for contact requests
-	log.Printf("Inbound connection is a contact request, but that's not implemented yet")
-	return errors.New("inbound contact request connections aren't implemented")
+	err = HandleInboundRequestConnection(rc, me.contactList)
+	if err == nil {
+		// Connection now belongs to an accepted contact, don't close it
+		conn = nil
+	}
+	return err
 }
 
 func (me *Identity) Address() string {

core/inboundcontactrequest.go

@@ -3,6 +3,7 @@ package core
 import (
 	"errors"
 	"github.com/ricochet-im/ricochet-go/rpc"
+	channels "github.com/s-rah/go-ricochet/channels"
 	connection "github.com/s-rah/go-ricochet/connection"
 	"log"
 	"sync"
@@ -10,17 +11,165 @@ import (
 )
 
 type InboundContactRequest struct {
-	core      *Ricochet
-	mutex     sync.Mutex
-	data      ricochet.ContactRequest
-	conn      *connection.Connection
-	channelID int32
-	Address   string
+	core    *Ricochet
+	mutex   sync.Mutex
+	data    ricochet.ContactRequest
+	Address string
+
+	// If non-nil, sent the new contact on accept or nil on reject.
+	// Used to signal back to active connections when request state changes.
+	contactResultChan chan *Contact
 
 	// Called when the request state is changed
 	StatusChanged func(request *InboundContactRequest)
 }
 
+type inboundRequestHandler struct {
+	Name    string
+	Message string
+
+	RequestReceivedChan chan struct{}
+	ResponseChan        chan string
+}
+
+func (irh *inboundRequestHandler) ContactRequestRejected() {}
+func (irh *inboundRequestHandler) ContactRequestAccepted() {}
+func (irh *inboundRequestHandler) ContactRequestError()    {}
+func (irh *inboundRequestHandler) ContactRequest(name, message string) string {
+	if len(name) > 0 && !IsNicknameAcceptable(name) {
+		log.Printf("protocol: Stripping unacceptable nickname from inbound request; encoded: %x", []byte(name))
+		name = ""
+	}
+	irh.Name = name
+	if len(message) > 0 && !IsMessageAcceptable(message) {
+		log.Printf("protocol: Stripping unacceptable message from inbound request; len: %d, encoded: %x", len(message), []byte(message))
+		message = ""
+	}
+	irh.Message = message
+
+	// Signal to the goroutine that a request was received
+	irh.RequestReceivedChan <- struct{}{}
+	// Wait for a response
+	response := <-irh.ResponseChan
+	return response
+}
+
+// HandleInboundRequestConnection takes an authenticated connection that does not
+// associate to any known contact and handles inbound contact request channels.
+// If no request is seen after a short timeout, the connection will be closed.
+// If a valid request is received, the connection will stay open to wait for the
+// user's reply.
+//
+// This function takes full ownership of the connection. On return, the connection
+// will be either closed and a non-nil error returned, or will be assigned to an
+// existing Contact along with a nil return value.
+func HandleInboundRequestConnection(conn *connection.Connection, contactList *ContactList) error {
+	log.Printf("Handling inbound contact request connection")
+	ach := &connection.AutoConnectionHandler{}
+	ach.Init()
+
+	// There may only ever be one contact request channel on the connection
+	req := &inboundRequestHandler{
+		RequestReceivedChan: make(chan struct{}),
+		ResponseChan:        make(chan string),
+	}
+	// XXX should close conn if the channel goes away...
+	ach.RegisterChannelHandler("im.ricochet.contact.request", func() channels.Handler {
+		return &channels.ContactRequestChannel{Handler: req}
+	})
+
+	processChan := make(chan error)
+	go func() {
+		processChan <- conn.Process(ach)
+	}()
+
+	address, ok := AddressFromPlainHost(conn.RemoteHostname)
+	if !ok {
+		conn.Conn.Close()
+		return <-processChan
+	}
+
+	// Expecting to receive request data within 15 seconds
+	select {
+	case <-req.RequestReceivedChan:
+		break
+	case err := <-processChan:
+		if err == nil {
+			conn.Conn.Close()
+			err = errors.New("unexpected break")
+		}
+		return err
+	case <-time.After(15 * time.Second):
+		// Didn't receive a contact request fast enough
+		conn.Conn.Close()
+		return <-processChan
+	}
+
+	// Function to respond to the request; changed after the initial response
+	respond := func(status string) { req.ResponseChan <- status }
+
+	request, contact := contactList.AddOrUpdateInboundContactRequest(address, req.Name, req.Message)
+	if contact == nil && request != nil && !request.IsRejected() {
+		// Pending request; keep connection open and wait for a user response
+		respond("Pending")
+		contactChan := request.getContactResultChannel()
+		select {
+		case c, ok := <-contactChan:
+			if !ok {
+				// Replaced by a different connection or otherwise cancelled without reply
+				conn.Conn.Close()
+				return <-processChan
+			}
+			// Set contact and fall out to handle the reply
+			contact = c
+			break
+		case err := <-processChan:
+			request.clearContactResultChannel(contactChan)
+			for {
+				_, ok := <-contactChan
+				if !ok {
+					break
+				}
+			}
+			return err
+		}
+
+		// Change how future responses are sent
+		respond = func(status string) {
+			conn.Do(func() error {
+				channel := conn.Channel("im.ricochet.contact.request", channels.Inbound)
+				if channel == nil {
+					return errors.New("no channel")
+				}
+				channel.Handler.(*channels.ContactRequestChannel).SendResponse(status)
+				// Also close the channel; this was a final response
+				channel.CloseChannel()
+				return nil
+			})
+		}
+	}
+
+	// Have a response (either immediately or after pending)
+	if contact != nil {
+		// Accepted
+		respond("Accepted")
+		if err := conn.Break(); err != nil {
+			// Connection lost; but request was accepted anyway, so it'll get reconnected later
+			return err
+		}
+		contact.AssignConnection(conn)
+		return nil
+	} else {
+		// Rejected
+		respond("Rejected")
+		if request != nil {
+			contactList.RemoveInboundContactRequest(request)
+		}
+		conn.Conn.Close()
+		return <-processChan
+	}
+}
+
 // CreateInboundContactRequest constructs a new InboundContactRequest, usually from a newly
 // received request on an open connection. Requests are managed through the ContactList, so
 // generally you should use ContactList.AddOrUpdateInboundContactRequest instead of calling
@@ -41,23 +190,35 @@ func CreateInboundContactRequest(core *Ricochet, address, nickname, message stri
 	return cr
 }
 
-// XXX-protocol There should be stricter management & a timeout for this connection
-func (cr *InboundContactRequest) SetConnection(conn *connection.Connection, channelID int32) {
+// getContactResultChannel returns a channel that will be sent a Contact if the request is
+// accepted, nil if the request is rejected, or closed if the channel is no longer used.
+// This is used to communciate with active connections for pending requests.
+func (cr *InboundContactRequest) getContactResultChannel() chan *Contact {
 	cr.mutex.Lock()
 	defer cr.mutex.Unlock()
 
-	if cr.conn != nil && cr.conn != conn {
-		log.Printf("Replacing connection on an inbound contact request")
-		cr.conn.Conn.Close()
+	if cr.contactResultChan != nil {
+		close(cr.contactResultChan)
+	}
+	cr.contactResultChan = make(chan *Contact)
+	return cr.contactResultChan
+}
+
+func (cr *InboundContactRequest) clearContactResultChannel(c chan *Contact) {
+	cr.mutex.Lock()
+	defer cr.mutex.Unlock()
+	if cr.contactResultChan == c {
+		close(cr.contactResultChan)
+		cr.contactResultChan = nil
 	}
-	cr.conn = conn
-	cr.channelID = channelID
 }
 
 func (cr *InboundContactRequest) CloseConnection() {
-	if cr.conn != nil {
-		cr.conn.Conn.Close()
-		cr.conn = nil
+	cr.mutex.Lock()
+	defer cr.mutex.Unlock()
+	if cr.contactResultChan != nil {
+		close(cr.contactResultChan)
+		cr.contactResultChan = nil
 	}
 }
 
@@ -117,27 +278,32 @@ func (cr *InboundContactRequest) Accept() (*Contact, error) {
 		return nil, err
 	}
 
-	if err := cr.AcceptWithContact(contact); err != nil {
+	if err := cr.acceptWithContact(contact); err != nil {
 		return contact, err
 	}
 	return contact, nil
 }
 
 func (cr *InboundContactRequest) AcceptWithContact(contact *Contact) error {
+	cr.mutex.Lock()
+	defer cr.mutex.Unlock()
+	return cr.acceptWithContact(contact)
+}
+
+// Assumes mutex
+func (cr *InboundContactRequest) acceptWithContact(contact *Contact) error {
 	if contact.Address() != cr.data.Address {
 		return errors.New("Contact address does not match request in accept")
 	}
 
-	cr.core.Identity.ContactList().RemoveInboundContactRequest(cr)
-
-	// Pass the open connection to the new contact
-	if cr.conn != nil {
-		// XXX-protocol cr.conn.AckContactRequest(cr.channelID, "Accepted")
-		// XXX-protocol cr.conn.CloseChannel(cr.channelID)
-		contact.AssignConnection(cr.conn)
-		cr.conn = nil
+	// Send to active connection if present
+	if cr.contactResultChan != nil {
+		cr.contactResultChan <- contact
+		close(cr.contactResultChan)
+		cr.contactResultChan = nil
 	}
 
+	cr.core.Identity.ContactList().RemoveInboundContactRequest(cr)
 	return nil
 }
 
@@ -152,20 +318,19 @@ func (cr *InboundContactRequest) Reject() {
 	log.Printf("Rejecting contact request from %s", cr.data.Address)
 	cr.data.Rejected = true
 
+	// Signal to the active connection
+	if cr.contactResultChan != nil {
+		cr.contactResultChan <- nil
+		close(cr.contactResultChan)
+		cr.contactResultChan = nil
+	}
+
 	// Signal update to the callback (probably from ContactList)
 	if cr.StatusChanged != nil {
 		cr.StatusChanged(cr)
 	}
 
-	if cr.conn != nil {
-		// XXX-protocol cr.conn.AckContactRequest(cr.channelID, "Rejected")
-		// XXX-protocol cr.conn.CloseChannel(cr.channelID)
-		cr.conn.Conn.Close()
-		cr.conn = nil
-
-		// The request can be removed once a protocol response is sent
-		cr.core.Identity.ContactList().RemoveInboundContactRequest(cr)
-	}
+	cr.core.Identity.ContactList().RemoveInboundContactRequest(cr)
 }
 
 func (cr *InboundContactRequest) Data() ricochet.ContactRequest {