new: SNI packet sniffer + sniffer refactoring.

modules/net_sniff_sni.go

@@ -0,0 +1,41 @@
+package modules
+
+import (
+	"fmt"
+
+	"github.com/evilsocket/bettercap-ng/core"
+	"regexp"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+)
+
+// poor man's TLS Client Hello with SNI extension parser :P
+var sniRe = regexp.MustCompile("\x00\x00.{4}\x00.{2}([a-z0-9]+([\\-\\.]{1}[a-z0-9]+)*\\.[a-z]{2,6})\x00")
+
+func sniParser(ip *layers.IPv4, pkt gopacket.Packet, tcp *layers.TCP) bool {
+	data := tcp.Payload
+	dataSize := len(data)
+
+	if dataSize < 2 || data[0] != 0x16 || data[1] != 0x03 {
+		return false
+	}
+
+	m := sniRe.FindSubmatch(data)
+	if len(m) < 2 {
+		return false
+	}
+
+	domain := string(m[1])
+	if tcp.DstPort != 443 {
+		domain = fmt.Sprintf("%s:%d", domain, tcp.DstPort)
+	}
+
+	fmt.Printf("[%s] %s %s > %s\n",
+		vTime(pkt.Metadata().Timestamp),
+		core.W(core.BG_YELLOW+core.FG_WHITE, "sni"),
+		vIP(ip.SrcIP),
+		core.Yellow("https://"+domain))
+
+	return true
+}