feat: peer wireguard (#2445)

agent/wireguard.go

@@ -0,0 +1,63 @@
+package agent
+
+import (
+	"context"
+
+	"golang.org/x/xerrors"
+	"inet.af/netaddr"
+
+	"cdr.dev/slog"
+	"github.com/coder/coder/peer/peerwg"
+)
+
+func (a *agent) startWireguard(ctx context.Context, addrs []netaddr.IPPrefix) error {
+	if a.network != nil {
+		_ = a.network.Close()
+		a.network = nil
+	}
+
+	// We can't create a wireguard network without these.
+	if len(addrs) == 0 || a.listenWireguardPeers == nil || a.postKeys == nil {
+		return xerrors.New("wireguard is enabled, but no addresses were provided or necessary functions were not provided")
+	}
+
+	wg, err := peerwg.New(a.logger.Named("wireguard"), addrs)
+	if err != nil {
+		return xerrors.Errorf("create wireguard network: %w", err)
+	}
+
+	// A new keypair is generated on each agent start.
+	// This keypair must be sent to Coder to allow for incoming connections.
+	err = a.postKeys(ctx, WireguardPublicKeys{
+		Public: wg.NodePrivateKey.Public(),
+		Disco:  wg.DiscoPublicKey,
+	})
+	if err != nil {
+		a.logger.Warn(ctx, "post keys", slog.Error(err))
+	}
+
+	go func() {
+		for {
+			ch, listenClose, err := a.listenWireguardPeers(ctx, a.logger)
+			if err != nil {
+				a.logger.Warn(ctx, "listen wireguard peers", slog.Error(err))
+				return
+			}
+
+			for {
+				peer, ok := <-ch
+				if !ok {
+					break
+				}
+
+				err := wg.AddPeer(peer)
+				a.logger.Info(ctx, "added wireguard peer", slog.F("peer", peer.NodePublicKey.ShortString()), slog.Error(err))
+			}
+
+			listenClose()
+		}
+	}()
+
+	a.network = wg
+	return nil
+}