netbird/client/iface/wgproxy/ebpf/wrapper.go

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//go:build linux && !android
package ebpf
import (
"context"
"errors"
"fmt"
"io"
"net"
"sync"
log "github.com/sirupsen/logrus"
)
// ProxyWrapper help to keep the remoteConn instance for net.Conn.Close function call
type ProxyWrapper struct {
WgeBPFProxy *WGEBPFProxy
remoteConn net.Conn
ctx context.Context
cancel context.CancelFunc
wgEndpointAddr *net.UDPAddr
pausedMu sync.Mutex
paused bool
isStarted bool
}
func (p *ProxyWrapper) AddTurnConn(ctx context.Context, endpoint *net.UDPAddr, remoteConn net.Conn) error {
addr, err := p.WgeBPFProxy.AddTurnConn(remoteConn)
if err != nil {
return fmt.Errorf("add turn conn: %w", err)
}
p.remoteConn = remoteConn
p.ctx, p.cancel = context.WithCancel(ctx)
p.wgEndpointAddr = addr
return err
}
func (p *ProxyWrapper) EndpointAddr() *net.UDPAddr {
return p.wgEndpointAddr
}
func (p *ProxyWrapper) Work() {
if p.remoteConn == nil {
return
}
p.pausedMu.Lock()
p.paused = false
p.pausedMu.Unlock()
if !p.isStarted {
p.isStarted = true
go p.proxyToLocal(p.ctx)
}
}
func (p *ProxyWrapper) Pause() {
if p.remoteConn == nil {
return
}
log.Tracef("pause proxy reading from: %s", p.remoteConn.RemoteAddr())
p.pausedMu.Lock()
p.paused = true
p.pausedMu.Unlock()
}
// CloseConn close the remoteConn and automatically remove the conn instance from the map
func (e *ProxyWrapper) CloseConn() error {
if e.cancel == nil {
return fmt.Errorf("proxy not started")
}
e.cancel()
if err := e.remoteConn.Close(); err != nil {
return fmt.Errorf("failed to close remote conn: %w", err)
}
return nil
}
func (p *ProxyWrapper) proxyToLocal(ctx context.Context) {
defer p.WgeBPFProxy.removeTurnConn(uint16(p.wgEndpointAddr.Port))
buf := make([]byte, 1500)
for {
n, err := p.readFromRemote(ctx, buf)
if err != nil {
return
}
p.pausedMu.Lock()
if p.paused {
p.pausedMu.Unlock()
continue
}
err = p.WgeBPFProxy.sendPkg(buf[:n], p.wgEndpointAddr.Port)
p.pausedMu.Unlock()
if err != nil {
if ctx.Err() != nil {
return
}
log.Errorf("failed to write out turn pkg to local conn: %v", err)
}
}
}
func (p *ProxyWrapper) readFromRemote(ctx context.Context, buf []byte) (int, error) {
n, err := p.remoteConn.Read(buf)
if err != nil {
if ctx.Err() != nil {
return 0, ctx.Err()
}
if !errors.Is(err, io.EOF) {
log.Errorf("failed to read from turn conn (endpoint: :%d): %s", p.wgEndpointAddr.Port, err)
}
return 0, err
}
return n, nil
}