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divert_embedded.go
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151 lines (128 loc) · 2.86 KB
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//go:build windows && (divert_rsrc || divert_embed) && (amd64 || 386 || arm64)
package divert
import (
"fmt"
"strconv"
"strings"
"sync"
"sync/atomic"
"syscall"
"unsafe"
"golang.org/x/sys/windows"
"github.com/imgk/divert-go/memmod"
)
var (
winDivert = (*lazyDLL)(nil)
winDivertOpen = (*lazyProc)(nil)
winDivertCalcChecksums = (*lazyProc)(nil)
)
// Open is ...
func Open(filter string, layer Layer, priority int16, flags uint64) (h *Handle, err error) {
once.Do(func() {
dll := newLazyDLL("WinDivert.dll", nil)
if er := dll.Load(); er != nil {
err = er
return
}
winDivert = dll
proc := winDivert.NewProc("WinDivertOpen")
if er := proc.Find(); er != nil {
err = er
return
}
winDivertOpen = proc
proc = winDivert.NewProc("WinDivertHelperCalcChecksums")
if er := proc.Find(); er != nil {
err = er
return
}
winDivertCalcChecksums = proc
vers := map[string]struct{}{
"2.0": {},
"2.1": {},
"2.2": {},
}
ver, er := func() (ver string, err error) {
h, err := open("false", LayerNetwork, PriorityDefault, FlagDefault)
if err != nil {
return
}
defer func() {
err = h.Close()
}()
major, err := h.GetParam(VersionMajor)
if err != nil {
return
}
minor, err := h.GetParam(VersionMinor)
if err != nil {
return
}
ver = strings.Join([]string{strconv.Itoa(int(major)), strconv.Itoa(int(minor))}, ".")
return
}()
if er != nil {
err = er
return
}
if _, ok := vers[ver]; !ok {
err = fmt.Errorf("unsupported windivert version: %v", ver)
}
})
if err != nil {
return
}
return open(filter, layer, priority, flags)
}
type lazyDLL struct {
Name string
Base windows.Handle
mu sync.Mutex
module *memmod.Module
onLoad func(d *lazyDLL)
}
func (p *lazyProc) nameToAddr() (uintptr, error) {
return p.dll.module.ProcAddressByName(p.Name)
}
func newLazyDLL(name string, onLoad func(d *lazyDLL)) *lazyDLL {
return &lazyDLL{Name: name, onLoad: onLoad}
}
func (d *lazyDLL) NewProc(name string) *lazyProc {
return &lazyProc{dll: d, Name: name}
}
type lazyProc struct {
Name string
mu sync.Mutex
dll *lazyDLL
addr uintptr
}
func (p *lazyProc) Find() error {
if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr))) != nil {
return nil
}
p.mu.Lock()
defer p.mu.Unlock()
if p.addr != 0 {
return nil
}
err := p.dll.Load()
if err != nil {
return fmt.Errorf("Error loading %v DLL: %w", p.dll.Name, err)
}
addr, err := p.nameToAddr()
if err != nil {
return fmt.Errorf("Error getting %v address: %w", p.Name, err)
}
atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr)), unsafe.Pointer(addr))
return nil
}
func (p *lazyProc) Addr() uintptr {
err := p.Find()
if err != nil {
panic(err)
}
return p.addr
}
func (p *lazyProc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) {
return syscall.SyscallN(p.Addr(), a...)
}