probelabs/goreplay · error

BPF filter error: %q, filter: %s

Error message

BPF filter error: %q, filter: %s

What it means

activatePcapFile fails when the BPF filter derived for the offline file cannot be applied via SetBPFFilter; the handle is closed and the error names the exact filter string that was rejected.

Source

Thrown at internal/capture/capture.go:696

	}
	return nil
}

func (l *Listener) activatePcapFile() (err error) {
	var handle *pcap.Handle
	var e error
	if handle, e = pcap.OpenOffline(l.host); e != nil {
		return fmt.Errorf("open pcap file error: %q", e)
	}

	tmp := l.host
	l.host = ""
	l.config.BPFFilter = l.Filter(pcap.Interface{})
	l.host = tmp

	if e = handle.SetBPFFilter(l.config.BPFFilter); e != nil {
		handle.Close()
		return fmt.Errorf("BPF filter error: %q, filter: %s", e, l.config.BPFFilter)
	}

	fmt.Println("BPF Filter:", l.config.BPFFilter)

	l.Handles["pcap_file"] = packetHandle{
		handler: handle,
	}
	return
}

func (l *Listener) activateAFPacket() error {
	szFrame, szBlock, numBlocks, err := afpacketComputeSize(32, 32<<10, os.Getpagesize())
	if err != nil {
		return err
	}

	var msg string
	for _, ifi := range l.Interfaces {

View on GitHub (pinned to 251e45abd2)

Solutions

1. Check the --input-raw-bpf-filter expression for syntax errors
2. Test the filter against the file with tcpdump -r <file> '<filter>'
3. Simplify the filter to isolate which clause is invalid

When it happens

Trigger: Thrown at internal/capture/capture.go:696 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/842cca6d6c6f1b7b. Report an issue: GitHub.