probelabs/goreplay · error

BPF filter error: %q%s, interface: %q

Error message

BPF filter error: %q%s, interface: %q

What it means

PcapHandle fails when SetBPFFilter rejects the BPF expression (explicit config filter or the auto-generated one); the handle is closed and the error reports the offending filter and interface so startup cannot continue with a broken capture.

Source

Thrown at internal/capture/capture.go:476

	}
	err = inactive.SetTimeout(l.config.BufferTimeout)
	if err != nil {
		return nil, fmt.Errorf("handle buffer timeout error: %q, interface: %q", err, ifi.Name)
	}
	handle, err = inactive.Activate()
	if err != nil {
		return nil, fmt.Errorf("PCAP Activate device error: %q, interface: %q", err, ifi.Name)
	}

	bpfFilter := l.config.BPFFilter
	if bpfFilter == "" {
		bpfFilter = l.Filter(ifi)
	}
	fmt.Println("Interface:", ifi.Name, ". BPF Filter:", bpfFilter)
	err = handle.SetBPFFilter(bpfFilter)
	if err != nil {
		handle.Close()
		return nil, fmt.Errorf("BPF filter error: %q%s, interface: %q", err, bpfFilter, ifi.Name)
	}
	return
}

// SocketHandle returns new unix ethernet handle associated with this listener settings
func (l *Listener) SocketHandle(ifi pcap.Interface) (handle Socket, err error) {
	handle, err = NewSocket(ifi)
	if err != nil {
		return nil, fmt.Errorf("sock raw error: %q, interface: %q", err, ifi.Name)
	}
	if err = handle.SetPromiscuous(l.config.Promiscuous || l.config.Monitor); err != nil {
		return nil, fmt.Errorf("promiscuous mode error: %q, interface: %q", err, ifi.Name)
	}
	if l.config.BPFFilter == "" {
		l.config.BPFFilter = l.Filter(ifi)
	}
	fmt.Println("BPF Filter: ", l.config.BPFFilter)
	if err = handle.SetBPFFilter(l.config.BPFFilter); err != nil {

View on GitHub (pinned to 251e45abd2)

Solutions

1. Validate the --input-raw-bpf-filter expression syntax (tcpdump accepts the same syntax)
2. Test the filter with tcpdump -i <iface> '<filter>' before using gor
3. Check the auto-generated filter isn't malformed on odd interfaces

When it happens

Trigger: Thrown at internal/capture/capture.go:476 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of probelabs/goreplay@251e45abd2 (2026-09-02). Data as JSON: /api/errors/91c2bdb9d4ef7314. Report an issue: GitHub.