new: centralized pcap capture configuration management

network/pcap.go

@@ -0,0 +1,71 @@
+package network
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/evilsocket/islazy/tui"
+	"github.com/google/gopacket/pcap"
+)
+
+const (
+	PCAP_DEFAULT_SETRF   = false
+	PCAP_DEFAULT_SNAPLEN = 65536
+	PCAP_DEFAULT_BUFSIZE = 2_097_152
+	PCAP_DEFAULT_PROMISC = true
+	PCAP_DEFAULT_TIMEOUT = pcap.BlockForever
+)
+
+var CAPTURE_DEFAULTS = CaptureOptions{
+	Monitor: PCAP_DEFAULT_SETRF,
+	Snaplen: PCAP_DEFAULT_SNAPLEN,
+	Bufsize: PCAP_DEFAULT_BUFSIZE,
+	Promisc: PCAP_DEFAULT_PROMISC,
+	Timeout: PCAP_DEFAULT_TIMEOUT,
+}
+
+type CaptureOptions struct {
+	Monitor bool
+	Snaplen int
+	Bufsize int
+	Promisc bool
+	Timeout time.Duration
+}
+
+func CaptureWithOptions(ifName string, options CaptureOptions) (*pcap.Handle, error) {
+	Debug("creating capture for '%s' with options: %+v", ifName, options)
+
+	ihandle, err := pcap.NewInactiveHandle(ifName)
+	if err != nil {
+		return nil, fmt.Errorf("error while opening interface %s: %s", ifName, err)
+	}
+	defer ihandle.CleanUp()
+
+	if options.Monitor {
+		if err = ihandle.SetRFMon(true); err != nil {
+			return nil, fmt.Errorf("error while setting interface %s in monitor mode: %s", tui.Bold(ifName), err)
+		}
+	}
+
+	if err = ihandle.SetSnapLen(options.Snaplen); err != nil {
+		return nil, fmt.Errorf("error while settng snapshot length: %s", err)
+	} else if err = ihandle.SetBufferSize(options.Bufsize); err != nil {
+		return nil, fmt.Errorf("error while settng buffer size: %s", err)
+	} else if err = ihandle.SetPromisc(options.Promisc); err != nil {
+		return nil, fmt.Errorf("error while settng promiscuous mode to %v: %s", options.Promisc, err)
+	} else if err = ihandle.SetTimeout(options.Timeout); err != nil {
+		return nil, fmt.Errorf("error while settng snapshot length: %s", err)
+	}
+
+	return ihandle.Activate()
+}
+
+func Capture(ifName string) (*pcap.Handle, error) {
+	return CaptureWithOptions(ifName, CAPTURE_DEFAULTS)
+}
+
+func CaptureWithTimeout(ifName string, timeout time.Duration) (*pcap.Handle, error) {
+	var opts = CAPTURE_DEFAULTS
+	opts.Timeout = timeout
+	return CaptureWithOptions(ifName, opts)
+}