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tailscale/net/netstat/netstat_windows.go

289 lines
7.9 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package netstat returns the local machine's network connection table.
package netstat
import (
"errors"
"fmt"
"math/bits"
"net/netip"
"unsafe"
"golang.org/x/sys/cpu"
"golang.org/x/sys/windows"
"tailscale.com/net/netaddr"
)
// OSMetadata includes any additional OS-specific information that may be
// obtained during the retrieval of a given Entry.
type OSMetadata interface {
// GetModule returns the entry's module name.
//
// It returns ("", nil) if no entry is found. As of 2023-01-27, any returned
// error is silently discarded by its sole caller in portlist_windows.go and
// treated equivalently as returning ("", nil), but this may change in the
// future. An error should only be returned in casees that are worthy of
// being logged at least.
GetModule() (string, error)
}
// See https://docs.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getextendedtcptable
// TCP_TABLE_OWNER_MODULE_ALL means to include the PID and module. The table type
// we get back from Windows depends on AF_INET vs AF_INET6:
// MIB_TCPTABLE_OWNER_MODULE for v4 or MIB_TCP6TABLE_OWNER_MODULE for v6.
const tcpTableOwnerModuleAll = 8
// TCPIP_OWNER_MODULE_BASIC_INFO means to request "basic information" about the
// owner module.
const tcpipOwnerModuleBasicInfo = 0
var (
iphlpapi = windows.NewLazySystemDLL("iphlpapi.dll")
getTCPTable = iphlpapi.NewProc("GetExtendedTcpTable")
getOwnerModuleFromTcpEntry = iphlpapi.NewProc("GetOwnerModuleFromTcpEntry")
getOwnerModuleFromTcp6Entry = iphlpapi.NewProc("GetOwnerModuleFromTcp6Entry")
// TODO: GetExtendedUdpTable also? if/when needed.
)
// See https://web.archive.org/web/20221219211913/https://learn.microsoft.com/en-us/windows/win32/api/tcpmib/ns-tcpmib-mib_tcprow_owner_module
type _MIB_TCPROW_OWNER_MODULE struct {
state uint32
localAddr uint32
localPort uint32
remoteAddr uint32
remotePort uint32
pid uint32
createTimestamp int64
owningModuleInfo [16]uint64
}
func (row *_MIB_TCPROW_OWNER_MODULE) asEntry() Entry {
return Entry{
Local: ipport4(row.localAddr, port(&row.localPort)),
Remote: ipport4(row.remoteAddr, port(&row.remotePort)),
Pid: int(row.pid),
State: state(row.state),
OSMetadata: row,
}
}
type _MIB_TCPTABLE_OWNER_MODULE struct {
numEntries uint32
table _MIB_TCPROW_OWNER_MODULE
}
func (m *_MIB_TCPTABLE_OWNER_MODULE) getRows() []_MIB_TCPROW_OWNER_MODULE {
return unsafe.Slice(&m.table, m.numEntries)
}
// See https://web.archive.org/web/20221219212442/https://learn.microsoft.com/en-us/windows/win32/api/tcpmib/ns-tcpmib-mib_tcp6row_owner_module
type _MIB_TCP6ROW_OWNER_MODULE struct {
localAddr [16]byte
localScope uint32
localPort uint32
remoteAddr [16]byte
remoteScope uint32
remotePort uint32
state uint32
pid uint32
createTimestamp int64
owningModuleInfo [16]uint64
}
func (row *_MIB_TCP6ROW_OWNER_MODULE) asEntry() Entry {
return Entry{
Local: ipport6(row.localAddr, row.localScope, port(&row.localPort)),
Remote: ipport6(row.remoteAddr, row.remoteScope, port(&row.remotePort)),
Pid: int(row.pid),
State: state(row.state),
OSMetadata: row,
}
}
type _MIB_TCP6TABLE_OWNER_MODULE struct {
numEntries uint32
table _MIB_TCP6ROW_OWNER_MODULE
}
func (m *_MIB_TCP6TABLE_OWNER_MODULE) getRows() []_MIB_TCP6ROW_OWNER_MODULE {
return unsafe.Slice(&m.table, m.numEntries)
}
// See https://web.archive.org/web/20221219213143/https://learn.microsoft.com/en-us/windows/win32/api/iprtrmib/ns-iprtrmib-tcpip_owner_module_basic_info
type _TCPIP_OWNER_MODULE_BASIC_INFO struct {
moduleName *uint16
modulePath *uint16
}
func get() (*Table, error) {
t := new(Table)
if err := t.addEntries(windows.AF_INET); err != nil {
return nil, fmt.Errorf("failed to get IPv4 entries: %w", err)
}
if err := t.addEntries(windows.AF_INET6); err != nil {
return nil, fmt.Errorf("failed to get IPv6 entries: %w", err)
}
return t, nil
}
func (t *Table) addEntries(fam int) error {
var size uint32
var addr unsafe.Pointer
var buf []byte
for {
err, _, _ := getTCPTable.Call(
uintptr(addr),
uintptr(unsafe.Pointer(&size)),
1, // sorted
uintptr(fam),
tcpTableOwnerModuleAll,
0, // reserved; "must be zero"
)
if err == 0 {
break
}
if err == uintptr(windows.ERROR_INSUFFICIENT_BUFFER) {
const maxSize = 10 << 20
if size > maxSize || size < 4 {
return fmt.Errorf("unreasonable kernel-reported size %d", size)
}
buf = make([]byte, size)
addr = unsafe.Pointer(&buf[0])
continue
}
return windows.Errno(err)
}
if len(buf) < int(size) {
return errors.New("unexpected size growth from system call")
}
buf = buf[:size]
switch fam {
case windows.AF_INET:
info := (*_MIB_TCPTABLE_OWNER_MODULE)(unsafe.Pointer(&buf[0]))
rows := info.getRows()
for _, row := range rows {
t.Entries = append(t.Entries, row.asEntry())
}
case windows.AF_INET6:
info := (*_MIB_TCP6TABLE_OWNER_MODULE)(unsafe.Pointer(&buf[0]))
rows := info.getRows()
for _, row := range rows {
t.Entries = append(t.Entries, row.asEntry())
}
}
return nil
}
var states = []string{
"",
"CLOSED",
"LISTEN",
"SYN-SENT",
"SYN-RECEIVED",
"ESTABLISHED",
"FIN-WAIT-1",
"FIN-WAIT-2",
"CLOSE-WAIT",
"CLOSING",
"LAST-ACK",
"DELETE-TCB",
}
func state(v uint32) string {
if v < uint32(len(states)) {
return states[v]
}
return fmt.Sprintf("unknown-state-%d", v)
}
func ipport4(addr uint32, port uint16) netip.AddrPort {
if !cpu.IsBigEndian {
addr = bits.ReverseBytes32(addr)
}
return netip.AddrPortFrom(
netaddr.IPv4(byte(addr>>24), byte(addr>>16), byte(addr>>8), byte(addr)),
port)
}
func ipport6(addr [16]byte, scope uint32, port uint16) netip.AddrPort {
ip := netip.AddrFrom16(addr).Unmap()
if scope != 0 {
// TODO: something better here?
ip = ip.WithZone(fmt.Sprint(scope))
}
return netip.AddrPortFrom(ip, port)
}
func port(v *uint32) uint16 {
if !cpu.IsBigEndian {
return uint16(bits.ReverseBytes32(*v) >> 16)
}
return uint16(*v >> 16)
}
type moduleInfoConstraint interface {
_MIB_TCPROW_OWNER_MODULE | _MIB_TCP6ROW_OWNER_MODULE
}
// moduleInfo implements OSMetadata.GetModule. It calls
// getOwnerModuleFromTcpEntry or getOwnerModuleFromTcp6Entry.
//
// See
// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getownermodulefromtcpentry
//
// It may return "", nil indicating a successful call but with empty data.
func moduleInfo[entryType moduleInfoConstraint](entry *entryType, proc *windows.LazyProc) (string, error) {
var buf []byte
var desiredLen uint32
var addr unsafe.Pointer
for {
e, _, _ := proc.Call(
uintptr(unsafe.Pointer(entry)),
uintptr(tcpipOwnerModuleBasicInfo),
uintptr(addr),
uintptr(unsafe.Pointer(&desiredLen)),
)
err := windows.Errno(e)
if err == windows.ERROR_SUCCESS {
break
}
if err == windows.ERROR_NOT_FOUND {
return "", nil
}
if err != windows.ERROR_INSUFFICIENT_BUFFER {
return "", err
}
if desiredLen > 1<<20 {
// Sanity check before allocating too much.
return "", nil
}
buf = make([]byte, desiredLen)
addr = unsafe.Pointer(&buf[0])
}
if addr == nil {
// GetOwnerModuleFromTcp*Entry can apparently return ERROR_SUCCESS
// (NO_ERROR) on the first call without the usual first
// ERROR_INSUFFICIENT_BUFFER result. Windows said success, so interpret
// that was sucessfully not having data.
return "", nil
}
basicInfo := (*_TCPIP_OWNER_MODULE_BASIC_INFO)(addr)
return windows.UTF16PtrToString(basicInfo.moduleName), nil
}
// GetModule implements OSMetadata.
func (m *_MIB_TCPROW_OWNER_MODULE) GetModule() (string, error) {
return moduleInfo(m, getOwnerModuleFromTcpEntry)
}
// GetModule implements OSMetadata.
func (m *_MIB_TCP6ROW_OWNER_MODULE) GetModule() (string, error) {
return moduleInfo(m, getOwnerModuleFromTcp6Entry)
}