Restore removePeer method

src/admin/removepeer.go

@@ -1,5 +1,10 @@
 package admin
 
+import (
+	"fmt"
+	"net/url"
+)
+
 type RemovePeerRequest struct {
 	Uri   string `json:"uri"`
 	Sintf string `json:"interface,omitempty"`
@@ -8,5 +13,9 @@ type RemovePeerRequest struct {
 type RemovePeerResponse struct{}
 
 func (a *AdminSocket) removePeerHandler(req *RemovePeerRequest, res *RemovePeerResponse) error {
-	return a.core.RemovePeer(req.Uri, req.Sintf)
+	u, err := url.Parse(req.Uri)
+	if err != nil {
+		return fmt.Errorf("unable to parse peering URI: %w", err)
+	}
+	return a.core.RemovePeer(u, req.Sintf)
 }

src/core/api.go

@@ -3,7 +3,6 @@ package core
 import (
 	"crypto/ed25519"
 	"encoding/json"
-	"fmt"
 	"net"
 	"net/url"
 	"sync/atomic"
@@ -192,28 +191,8 @@ func (c *Core) AddPeer(u *url.URL, sintf string) error {
 
 // RemovePeer removes a peer. The peer should be specified in URI format, see AddPeer.
 // The peer is not disconnected immediately.
-func (c *Core) RemovePeer(uri string, sourceInterface string) error {
-	return fmt.Errorf("not implemented yet")
-	/*
-		var err error
-		phony.Block(c, func() {
-			peer := Peer{uri, sourceInterface}
-			linkInfo, ok := c.config._peers[peer]
-			if !ok {
-				err = fmt.Errorf("peer not configured")
-				return
-			}
-			if ok && linkInfo != nil {
-				c.links.Act(nil, func() {
-					if link := c.links._links[*linkInfo]; link != nil {
-						_ = link.conn.Close()
-					}
-				})
-			}
-			delete(c.config._peers, peer)
-		})
-		return err
-	*/
+func (c *Core) RemovePeer(u *url.URL, sintf string) error {
+	return c.links.remove(u, sintf, linkTypePersistent)
 }
 
 // CallPeer calls a peer once. This should be specified in the peer URI format,

src/core/link.go

@@ -53,6 +53,8 @@ type linkInfo struct {
 
 // link tracks the state of a connection, either persistent or non-persistent
 type link struct {
+	ctx       context.Context    // Connection context
+	cancel    context.CancelFunc // Stop future redial attempts (when peer removed)
 	kick      chan struct{}      // Attempt to reconnect now, if backing off
 	linkType  linkType           // Type of link, i.e. outbound/inbound, persistent/ephemeral
 	linkProto string             // Protocol carrier of link, e.g. TCP, AWDL
@@ -129,6 +131,7 @@ type linkError string
 func (e linkError) Error() string { return string(e) }
 
 const ErrLinkAlreadyConfigured = linkError("peer is already configured")
+const ErrLinkNotConfigured = linkError("peer is not configured")
 const ErrLinkPriorityInvalid = linkError("priority value is invalid")
 const ErrLinkPinnedKeyInvalid = linkError("pinned public key is invalid")
 const ErrLinkPasswordInvalid = linkError("password is invalid")
@@ -199,6 +202,7 @@ func (l *links) add(u *url.URL, sintf string, linkType linkType) error {
 			linkProto: strings.ToUpper(u.Scheme),
 			kick:      make(chan struct{}),
 		}
+		state.ctx, state.cancel = context.WithCancel(l.core.ctx)
 
 		// Store the state of the link so that it can be queried later.
 		l._links[info] = state
@@ -218,12 +222,14 @@ func (l *links) add(u *url.URL, sintf string, linkType linkType) error {
 			backoff++
 			duration := time.Second * time.Duration(math.Exp2(float64(backoff)))
 			select {
-			case <-time.After(duration):
-				return true
 			case <-state.kick:
 				return true
+			case <-state.ctx.Done():
+				return false
 			case <-l.core.ctx.Done():
 				return false
+			case <-time.After(duration):
+				return true
 			}
 		}
 
@@ -232,19 +238,25 @@ func (l *links) add(u *url.URL, sintf string, linkType linkType) error {
 		// then the loop will run endlessly, using backoffs as needed.
 		// Otherwise the loop will end, cleaning up the link entry.
 		go func() {
-			defer func() {
-				phony.Block(l, func() {
+			defer phony.Block(l, func() {
 				if l._links[info] == state {
 					delete(l._links, info)
 				}
 			})
-			}()
 
 			// This loop will run each and every time we want to attempt
 			// a connection to this peer.
 			// TODO get rid of this loop, this is *exactly* what time.AfterFunc is for, we should just send a signal to the links actor to kick off a goroutine as needed
 			for {
-				conn, err := l.connect(u, info, options)
+				select {
+				case <-state.ctx.Done():
+					// The peering context has been cancelled, so don't try
+					// to dial again.
+					return
+				default:
+				}
+
+				conn, err := l.connect(state.ctx, u, info, options)
 				if err != nil {
 					if linkType == linkTypePersistent {
 						// If the link is a persistent configured peering,
@@ -319,13 +331,39 @@ func (l *links) add(u *url.URL, sintf string, linkType linkType) error {
 					}
 					return
 				}
-				break
 			}
 		}()
 	})
 	return retErr
 }
 
+func (l *links) remove(u *url.URL, sintf string, linkType linkType) error {
+	var retErr error
+	phony.Block(l, func() {
+		// Generate the link info and see whether we think we already
+		// have an open peering to this peer.
+		lu := urlForLinkInfo(*u)
+		info := linkInfo{
+			uri:   lu.String(),
+			sintf: sintf,
+		}
+
+		// If this peer is already configured then we will close the
+		// connection and stop it from retrying.
+		state, ok := l._links[info]
+		if ok && state != nil {
+			state.cancel()
+			if conn := state._conn; conn != nil {
+				retErr = conn.Close()
+			}
+			return
+		}
+
+		retErr = ErrLinkNotConfigured
+	})
+	return retErr
+}
+
 func (l *links) listen(u *url.URL, sintf string) (*Listener, error) {
 	ctx, cancel := context.WithCancel(l.core.ctx)
 	var protocol linkProtocol
@@ -453,7 +491,7 @@ func (l *links) listen(u *url.URL, sintf string) (*Listener, error) {
 	return li, nil
 }
 
-func (l *links) connect(u *url.URL, info linkInfo, options linkOptions) (net.Conn, error) {
+func (l *links) connect(ctx context.Context, u *url.URL, info linkInfo, options linkOptions) (net.Conn, error) {
 	var dialer linkProtocol
 	switch strings.ToLower(u.Scheme) {
 	case "tcp":
@@ -485,7 +523,7 @@ func (l *links) connect(u *url.URL, info linkInfo, options linkOptions) (net.Con
 	default:
 		return nil, ErrLinkUnrecognisedSchema
 	}
-	return dialer.dial(l.core.ctx, u, info, options)
+	return dialer.dial(ctx, u, info, options)
 }
 
 func (l *links) handler(linkType linkType, options linkOptions, conn net.Conn) error {