added HID support for Microsoft devices

modules/hid/build_microsoft.go

@@ -0,0 +1,69 @@
+package hid
+
+import (
+	"fmt"
+
+	"github.com/bettercap/bettercap/network"
+)
+
+type MicrosoftBuilder struct {
+	seqn uint16
+}
+
+func (b MicrosoftBuilder) frameFor(template []byte, cmd *Command) []byte {
+	data := make([]byte, len(template))
+	copy(data, template)
+
+	data[4] = byte(b.seqn & 0xff)
+	data[5] = byte((b.seqn >> 8) & 0xff)
+	data[7] = cmd.Mode
+	data[9] = cmd.HID
+	// MS checksum algorithm - as per KeyKeriki paper
+	sum := byte(0)
+	last := len(data) - 1
+	for i := 0; i < last; i++ {
+		sum ^= data[i]
+	}
+	sum = ^sum & 0xff
+	data[last] = sum
+
+	b.seqn++
+
+	return data
+}
+
+func (b MicrosoftBuilder) BuildFrames(dev *network.HIDDevice, commands []*Command) error {
+	tpl := ([]byte)(nil)
+	dev.EachPayload(func(p []byte) bool {
+		if len(p) == 19 {
+			tpl = p
+			return true
+		}
+		return false
+	})
+
+	if tpl == nil {
+		return fmt.Errorf("at least one packet of 19 bytes needed to hijack microsoft devices, try to hid.sniff the device first")
+	}
+
+	last := len(commands) - 1
+	for i, cmd := range commands {
+		next := (*Command)(nil)
+		if i < last {
+			next = commands[i+1]
+		}
+
+		if cmd.IsHID() {
+			cmd.AddFrame(b.frameFor(tpl, cmd), 5)
+			if next == nil || cmd.HID == next.HID || next.IsSleep() {
+				cmd.AddFrame(b.frameFor(tpl, &Command{}), 0)
+			}
+		} else if cmd.IsSleep() {
+			for i, num := 0, cmd.Sleep/10; i < num; i++ {
+				cmd.AddFrame(b.frameFor(tpl, &Command{}), 0)
+			}
+		}
+	}
+
+	return nil
+}