ooni-probe-cli/internal/netxlite/trace.go
DecFox 2301a30630
feat: context-based tracing to record delayed DNS responses (#870)
See https://github.com/ooni/probe/issues/2221

Co-authored-by: decfox <decfox@github.com>
Co-authored-by: Simone Basso <bassosimone@gmail.com>
2022-08-22 14:21:32 +02:00

101 lines
3.2 KiB
Go

package netxlite
//
// Context-based tracing
//
import (
"context"
"crypto/tls"
"net"
"time"
"github.com/lucas-clemente/quic-go"
"github.com/ooni/probe-cli/v3/internal/model"
"github.com/ooni/probe-cli/v3/internal/runtimex"
)
// traceKey is the private type used to set/retrieve the context's trace.
type traceKey struct{}
// ContextTraceOrDefault retrieves the trace bound to the context or returns
// a default implementation of the trace in case no tracing was configured.
func ContextTraceOrDefault(ctx context.Context) model.Trace {
t, _ := ctx.Value(traceKey{}).(model.Trace)
return traceOrDefault(t)
}
// ContextWithTrace returns a new context that binds to the given trace. If the
// given trace is nil, this function will call panic.
func ContextWithTrace(ctx context.Context, trace model.Trace) context.Context {
runtimex.PanicIfTrue(trace == nil, "netxlite.WithTrace passed a nil trace")
return context.WithValue(ctx, traceKey{}, trace)
}
// traceOrDefault takes in input a trace and returns in output the
// given trace, if not nil, or a default trace implementation.
func traceOrDefault(trace model.Trace) model.Trace {
if trace != nil {
return trace
}
return &traceDefault{}
}
// traceDefault is a default model.Trace implementation where each method is a no-op.
type traceDefault struct{}
var _ model.Trace = &traceDefault{}
// TimeNow implements model.Trace.TimeNow
func (*traceDefault) TimeNow() time.Time {
return time.Now()
}
// MaybeWrapNetConn implements model.Trace.MaybeWrapNetConn
func (*traceDefault) MaybeWrapNetConn(conn net.Conn) net.Conn {
return conn
}
// MaybeWrapUDPLikeConn implements model.Trace.MaybeWrapUDPLikeConn
func (*traceDefault) MaybeWrapUDPLikeConn(conn model.UDPLikeConn) model.UDPLikeConn {
return conn
}
// OnDNSRoundTripForLookupHost implements model.Trace.OnDNSRoundTripForLookupHost.
func (*traceDefault) OnDNSRoundTripForLookupHost(started time.Time, reso model.Resolver, query model.DNSQuery,
response model.DNSResponse, addrs []string, err error, finished time.Time) {
// nothing
}
// OnDelayedDNSResponse implements model.Trace.OnDelayedDNSResponse.
func (*traceDefault) OnDelayedDNSResponse(started time.Time, txp model.DNSTransport,
query model.DNSQuery, response model.DNSResponse, addrs []string, err error, finished time.Time) error {
return nil
}
// OnConnectDone implements model.Trace.OnConnectDone.
func (*traceDefault) OnConnectDone(
started time.Time, network, domain, remoteAddr string, err error, finished time.Time) {
// nothing
}
// OnTLSHandshakeStart implements model.Trace.OnTLSHandshakeStart.
func (*traceDefault) OnTLSHandshakeStart(now time.Time, remoteAddr string, config *tls.Config) {
// nothing
}
// OnTLSHandshakeDone implements model.Trace.OnTLSHandshakeDone.
func (*traceDefault) OnTLSHandshakeDone(started time.Time, remoteAddr string, config *tls.Config,
state tls.ConnectionState, err error, finished time.Time) {
// nothing
}
func (*traceDefault) OnQUICHandshakeStart(now time.Time, remoteAddr string, config *quic.Config) {
// nothing
}
func (*traceDefault) OnQUICHandshakeDone(started time.Time, remoteAddr string, qconn quic.EarlyConnection,
config *tls.Config, err error, finished time.Time) {
// nothing
}