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node.go
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node.go
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package diet256
import (
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"net/netip"
"sync"
"time"
"github.com/brendoncarroll/go-p2p"
"github.com/brendoncarroll/go-p2p/s/swarmutil"
"github.com/brendoncarroll/stdctx/logctx"
"github.com/inet256/diet256/internal/protocol"
"github.com/inet256/inet256/pkg/inet256"
"github.com/quic-go/quic-go"
"go.uber.org/zap"
"golang.org/x/sync/errgroup"
"google.golang.org/grpc"
)
type Node struct {
client *Client
privateKey inet256.PrivateKey
localAddr inet256.ID
tlsConfig *tls.Config
quicConfig *quic.Config
baseConn net.PacketConn
lis quic.Listener
tellHub *swarmutil.TellHub[inet256.Addr]
ctrlClientMu sync.Mutex
ctrlConn quic.Connection
ctrlClient protocol.ControlClient
mu sync.RWMutex
sessions map[sessionKey]quic.Connection
ctx context.Context
cf context.CancelFunc
eg errgroup.Group
}
func newNode(bgCtx context.Context, c *Client, privateKey inet256.PrivateKey) (*Node, error) {
baseConn, err := c.lpc(context.Background(), "udp4", "0.0.0.0:0")
if err != nil {
return nil, err
}
lis, err := quic.Listen(baseConn, generateServerTLS(privateKey), generateQUICConfig())
if err != nil {
return nil, err
}
ctx, cf := context.WithCancel(bgCtx)
th := swarmutil.NewTellHub[inet256.Addr]()
n := &Node{
client: c,
privateKey: privateKey,
localAddr: inet256.NewAddr(privateKey.Public()),
tlsConfig: generateClientTLS(privateKey),
quicConfig: generateQUICConfig(),
baseConn: baseConn,
lis: lis,
tellHub: &th,
sessions: make(map[sessionKey]quic.Connection),
ctx: ctx,
cf: cf,
}
n.eg.Go(func() error {
if err := n.baseReadLoop(ctx); errors.Is(err, context.Canceled) {
err = nil
}
return nil
})
n.eg.Go(func() error {
if err := n.listenLoop(ctx); err != nil {
err = nil
}
return nil
})
return n, nil
}
func (n *Node) Send(ctx context.Context, dst inet256.Addr, data []byte) error {
sess, err := n.getSession(ctx, dst)
if err != nil {
return err
}
return sess.SendMessage(data)
}
func (n *Node) Receive(ctx context.Context, fn func(inet256.Message)) error {
return n.tellHub.Receive(ctx, func(x p2p.Message[inet256.Addr]) {
fn(inet256.Message{
Src: x.Src,
Dst: x.Dst,
Payload: x.Payload,
})
})
}
func (n *Node) FindAddr(ctx context.Context, prefix []byte, nbits int) (inet256.Addr, error) {
return retryN(5, 100*time.Millisecond, func() (inet256.Addr, error) {
client, err := n.getControlClient(ctx)
if err != nil {
return inet256.Addr{}, err
}
res, err := client.FindAddr(ctx, &protocol.FindAddrReq{
Prefix: prefix,
Nbits: int32(nbits),
})
if err != nil {
return inet256.Addr{}, err
}
return inet256.AddrFromBytes(res.Addr), nil
}, func(err error) {
logctx.Warnf(ctx, "error during FindAddr %v, retrying...", err)
})
}
func (n *Node) LookupPublicKey(ctx context.Context, target inet256.Addr) (inet256.PublicKey, error) {
return retryN[inet256.PublicKey](5, 100*time.Millisecond, func() (inet256.PublicKey, error) {
client, err := n.getControlClient(ctx)
if err != nil {
return nil, err
}
res, err := client.LookupPublicKey(ctx, &protocol.LookupPublicKeyReq{
Target: target[:],
})
if err != nil {
return nil, err
}
return inet256.ParsePublicKey(res.PublicKey)
}, func(err error) {
logctx.Warnf(ctx, "error during LookupPublicKey %v, retrying...", err)
})
}
func (n *Node) LocalAddr() inet256.Addr {
return n.localAddr
}
func (n *Node) PublicKey() inet256.PublicKey {
return n.privateKey.Public()
}
func (n *Node) Close() error {
return n.client.Drop(context.TODO(), n.privateKey)
}
func (n *Node) close() error {
n.cf()
n.lis.Close()
return n.eg.Wait()
}
func (n *Node) getSession(ctx context.Context, dst inet256.Addr) (quic.Connection, error) {
n.mu.RLock()
sess1 := n.sessions[sessionKey{ID: dst, IsOutbound: false}]
sess2 := n.sessions[sessionKey{ID: dst, IsOutbound: true}]
n.mu.RUnlock()
var sess quic.Connection
switch {
case sess1 != nil:
sess = sess1
case sess2 != nil:
sess = sess2
default:
newSess, err := n.dialPeer(ctx, dst)
if err != nil {
return nil, err
}
sess = newSess
go n.serveSession(sess, true)
}
return sess, nil
}
// dialPeer looks up the address of peer using the control plane and then attempts to connect to it.
func (n *Node) dialPeer(ctx context.Context, dst inet256.Addr) (ret quic.Connection, retErr error) {
log := logctx.FromContext(ctx)
log = log.With(zap.Any("peer", dst))
log.Info("begin dial loop")
defer func() {
if retErr == nil {
log.Info("connected to peer", zap.Any("remote_addr", ret.RemoteAddr()))
}
}()
return retryN(10, 100*time.Millisecond, func() (quic.Connection, error) {
client, err := n.getControlClient(ctx)
if err != nil {
return nil, err
}
res, err := client.Dial(ctx, &protocol.DialReq{Target: dst[:]})
if err != nil {
return nil, err
}
raddr, err := netip.ParseAddrPort(res.Addr)
if err != nil {
return nil, err
}
raddr = fixAddrPort(raddr)
return n.dialPeerAt(ctx, dst, raddr)
}, func(err error) {
log.Warn("error dialing. retying...")
})
}
// dialPeerAddr connects to a specific peer at a specific netip.AddrPort
func (n *Node) dialPeerAt(ctx context.Context, id inet256.Addr, raddr netip.AddrPort) (quic.Connection, error) {
log := logctx.FromContext(ctx)
log = log.With(zap.Any("peer", id), zap.Any("raddr", raddr), zap.Any("laddr", n.baseConn.LocalAddr()))
udpAddr := net.UDPAddrFromAddrPort(raddr)
// TODO: lock the remote address
log.Info("dialing peer")
sess, err := quic.DialContext(ctx, n.baseConn, udpAddr, "", n.tlsConfig.Clone(), n.quicConfig)
if err != nil {
return nil, err
}
actualID, _, err := peerFromQUICConn(sess)
if err != nil {
return nil, err
}
if actualID != id {
return nil, fmt.Errorf("got bad peer ID HAVE: %v WANT: %v", actualID, id)
}
return sess, nil
}
func (n *Node) listenLoop(ctx context.Context) error {
return retryForever(ctx, time.Second, func() error {
client, err := n.getControlClient(ctx)
if err != nil {
return err
}
lc, err := client.Listen(ctx, &protocol.ListenReq{})
if err != nil {
return err
}
for {
lr, err := lc.Recv()
if err != nil {
if errors.Is(err, io.EOF) {
return nil
}
return err
}
id := inet256.AddrFromBytes(lr.Id)
addrPort, err := netip.ParseAddrPort(lr.Addr)
if err != nil {
return err
}
addrPort = fixAddrPort(addrPort)
go func() {
sess, err := retryN(1, 100*time.Millisecond, func() (quic.Connection, error) {
return n.dialPeerAt(n.ctx, id, addrPort)
}, func(error) {})
if err != nil {
logctx.Warnln(ctx, "error during pre-emptive dial", err)
} else {
n.serveSession(sess, true)
}
}()
}
}, func(err error) {
logctx.Warnln(ctx, "error in listen loop: ", err)
})
}
func (node *Node) getControlClient(ctx context.Context) (protocol.ControlClient, error) {
node.ctrlClientMu.Lock()
defer node.ctrlClientMu.Unlock()
if node.ctrlClient != nil {
return node.ctrlClient, nil
}
cc, err := node.dialControlClient(ctx)
if err != nil {
return nil, err
}
node.ctrlClient = cc
return cc, nil
}
func (node *Node) dialControlClient(ctx context.Context) (protocol.ControlClient, error) {
tlsConfig := generateClientTLS(node.privateKey)
gc, err := grpc.DialContext(ctx, "", grpc.WithContextDialer(func(ctx context.Context, raddr string) (net.Conn, error) {
serverAddr, err := node.client.getServerUDPAddr()
if err != nil {
return nil, err
}
var ctrlConn quic.Connection
if node.ctrlConn != nil && node.ctrlConn.Context().Err() != nil {
node.ctrlConn.CloseWithError(0, "connection errored")
node.ctrlConn = nil
}
if node.ctrlConn == nil {
logctx.Infof(ctx, "dialing control plane %v...", serverAddr)
sess, err := quic.Dial(node.baseConn, serverAddr, "", tlsConfig, generateQUICConfig())
if err != nil {
return nil, err
}
ctrlConn = sess
}
stream, err := ctrlConn.OpenStream()
if err != nil {
return nil, err
}
return newConn(ctrlConn, stream), nil
}), grpc.WithTransportCredentials(transportCreds{ServerID: node.client.getServerID()}))
if err != nil {
return nil, err
}
return protocol.NewControlClient(gc), nil
}
func (node *Node) baseReadLoop(ctx context.Context) error {
for {
sess, err := node.lis.Accept(ctx)
if err != nil {
return err
}
serverAddr, err := node.client.getServerUDPAddr()
if err != nil {
return err
}
if sess.RemoteAddr().String() == serverAddr.String() {
sess.CloseWithError(quic.ApplicationErrorCode(1), "server should not dial client")
continue
}
go node.serveSession(sess, false)
}
}
func (node *Node) serveSession(sess quic.Connection, isOutbound bool) error {
ctx := node.ctx
defer sess.CloseWithError(1, "closing session")
from, _, err := peerFromQUICConn(sess)
if err != nil {
return err
}
sk := sessionKey{ID: from, IsOutbound: isOutbound}
node.mu.Lock()
if old, exists := node.sessions[sk]; exists {
old.CloseWithError(1, "newer session")
delete(node.sessions, sk)
}
node.sessions[sk] = sess
node.mu.Unlock()
defer func() {
node.mu.Lock()
delete(node.sessions, sk)
node.mu.Unlock()
}()
for {
data, err := sess.ReceiveMessage()
if err != nil {
return err
}
if err := func() error {
return node.tellHub.Deliver(ctx, p2p.Message[inet256.Addr]{
Src: from,
Dst: node.localAddr,
Payload: data,
})
}(); err != nil {
logctx.Warnln(ctx, "error handling stream", err)
}
}
}
type sessionKey struct {
ID inet256.ID
IsOutbound bool
}
func retryN[T any](n int, d time.Duration, fn func() (T, error), onError func(err error)) (T, error) {
var retErr error
for i := 0; i < n; i++ {
y, err := fn()
if err != nil {
onError(err)
retErr = err
} else {
return y, nil
}
time.Sleep(d)
}
var y T
return y, retErr
}
func retryForever(ctx context.Context, d time.Duration, fn func() error, onErr func(error)) error {
for {
if err := fn(); err != nil {
onErr(err)
}
select {
case <-ctx.Done():
return ctx.Err()
case <-time.After(d):
}
}
}
func fixAddrPort(x netip.AddrPort) netip.AddrPort {
ip := x.Addr()
if ip.Is4In6() {
return netip.AddrPortFrom(netip.AddrFrom4(ip.As4()), x.Port())
}
return x
}