caddy/listeners.go at master · bit/caddy · GitHub

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// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

package caddy

import (

"context"

"crypto/tls"

"errors"

"fmt"

"io"

"net"

"net/netip"

"os"

"strconv"

"strings"

"sync"

"sync/atomic"

"syscall"

"time"

"github.com/lucas-clemente/quic-go"

"github.com/lucas-clemente/quic-go/http3"

"go.uber.org/zap"

)

// NetworkAddress represents one or more network addresses.

// It contains the individual components for a parsed network

// address of the form accepted by ParseNetworkAddress().

type NetworkAddress struct {

// Should be a network value accepted by Go's net package or

// by a plugin providing a listener for that network type.

Network string

// The "main" part of the network address is the host, which

// often takes the form of a hostname, DNS name, IP address,

// or socket path.

Host string

// For addresses that contain a port, ranges are given by

// [StartPort, EndPort]; i.e. for a single port, StartPort

// and EndPort are the same. For no port, they are 0.

StartPort uint

EndPort uint

}

// ListenAll calls Listen() for all addresses represented by this struct, i.e. all ports in the range.

// (If the address doesn't use ports or has 1 port only, then only 1 listener will be created.)

// It returns an error if any listener failed to bind, and closes any listeners opened up to that point.

// TODO: Experimental API: subject to change or removal.

func (na NetworkAddress) ListenAll(ctx context.Context, config net.ListenConfig) ([]any, error) {

var listeners []any

var err error

// if one of the addresses has a failure, we need to close

// any that did open a socket to avoid leaking resources

defer func() {

if err == nil {

return

}

for _, ln := range listeners {

if cl, ok := ln.(io.Closer); ok {

cl.Close()

}

}()

// an address can contain a port range, which represents multiple addresses;

// some addresses don't use ports at all and have a port range size of 1;

// whatever the case, iterate each address represented and bind a socket

for portOffset := uint(0); portOffset < na.PortRangeSize(); portOffset++ {

select {

case <-ctx.Done():

return nil, ctx.Err()

default:

}

// create (or reuse) the listener ourselves

var ln any

ln, err = na.Listen(ctx, portOffset, config)

if err != nil {

return nil, err

}

listeners = append(listeners, ln)

}

return listeners, nil

}

// Listen is similar to net.Listen, with a few differences:

// Listen announces on the network address using the port calculated by adding

// portOffset to the start port. (For network types that do not use ports, the

// portOffset is ignored.)

// The provided ListenConfig is used to create the listener. Its Control function,

// if set, may be wrapped by an internally-used Control function. The provided

// context may be used to cancel long operations early. The context is not used

// to close the listener after it has been created.

// Caddy's listeners can overlap each other: multiple listeners may be created on

// the same socket at the same time. This is useful because during config changes,

// the new config is started while the old config is still running. How this is

// accomplished varies by platform and network type. For example, on Unix, SO_REUSEPORT

// is set except on Unix sockets, for which the file descriptor is duplicated and

// reused; on Windows, the close logic is virtualized using timeouts. Like normal

// listeners, be sure to Close() them when you are done.

// This method returns any type, as the implementations of listeners for various

// network types are not interchangeable. The type of listener returned is switched

// on the network type. Stream-based networks ("tcp", "unix", "unixpacket", etc.)

// return a net.Listener; datagram-based networks ("udp", "unixgram", etc.) return

// a net.PacketConn; and so forth. The actual concrete types are not guaranteed to

// be standard, exported types (wrapping is necessary to provide graceful reloads).

// Unix sockets will be unlinked before being created, to ensure we can bind to

// it even if the previous program using it exited uncleanly; it will also be

// unlinked upon a graceful exit (or when a new config does not use that socket).

// TODO: Experimental API: subject to change or removal.

func (na NetworkAddress) Listen(ctx context.Context, portOffset uint, config net.ListenConfig) (any, error) {

if na.IsUnixNetwork() {

unixSocketsMu.Lock()

defer unixSocketsMu.Unlock()

}

// check to see if plugin provides listener

if ln, err := getListenerFromPlugin(ctx, na.Network, na.JoinHostPort(portOffset), config); ln != nil || err != nil {

return ln, err

}

// create (or reuse) the listener ourselves

return na.listen(ctx, portOffset, config)

}

func (na NetworkAddress) listen(ctx context.Context, portOffset uint, config net.ListenConfig) (any, error) {

var ln any

var err error

address := na.JoinHostPort(portOffset)

// if this is a unix socket, see if we already have it open

if socket, err := reuseUnixSocket(na.Network, address); socket != nil || err != nil {

return socket, err

}

lnKey := listenerKey(na.Network, address)

switch na.Network {

case "tcp", "tcp4", "tcp6", "unix", "unixpacket":

ln, err = listenTCPOrUnix(ctx, lnKey, na.Network, address, config)

case "unixgram":

ln, err = config.ListenPacket(ctx, na.Network, address)

case "udp", "udp4", "udp6":

sharedPc, _, err := listenerPool.LoadOrNew(lnKey, func() (Destructor, error) {

pc, err := config.ListenPacket(ctx, na.Network, address)

if err != nil {

return nil, err

}

return &sharedPacketConn{PacketConn: pc, key: lnKey}, nil

})

if err != nil {

return nil, err

}

ln = &fakeClosePacketConn{sharedPacketConn: sharedPc.(*sharedPacketConn)}

}

if strings.HasPrefix(na.Network, "ip") {

ln, err = config.ListenPacket(ctx, na.Network, address)

}

if err != nil {

return nil, err

}

if ln == nil {

return nil, fmt.Errorf("unsupported network type: %s", na.Network)

}

// if new listener is a unix socket, make sure we can reuse it later

// (we do our own "unlink on close" -- not required, but more tidy)

one := int32(1)

switch unix := ln.(type) {

case *net.UnixListener:

unix.SetUnlinkOnClose(false)

ln = &unixListener{unix, lnKey, &one}

unixSockets[lnKey] = ln.(*unixListener)

case *net.UnixConn:

ln = &unixConn{unix, address, lnKey, &one}

unixSockets[lnKey] = ln.(*unixConn)

}

return ln, nil

}

// IsUnixNetwork returns true if na.Network is

// unix, unixgram, or unixpacket.

func (na NetworkAddress) IsUnixNetwork() bool {

return isUnixNetwork(na.Network)

}

// JoinHostPort is like net.JoinHostPort, but where the port

// is StartPort + offset.

func (na NetworkAddress) JoinHostPort(offset uint) string {

if na.IsUnixNetwork() {

return na.Host

}

return net.JoinHostPort(na.Host, strconv.Itoa(int(na.StartPort+offset)))

}

// Expand returns one NetworkAddress for each port in the port range.

// This is EXPERIMENTAL and subject to change or removal.

func (na NetworkAddress) Expand() []NetworkAddress {

size := na.PortRangeSize()

addrs := make([]NetworkAddress, size)

for portOffset := uint(0); portOffset < size; portOffset++ {

addrs[portOffset] = na.At(portOffset)

}

return addrs

}

// At returns a NetworkAddress with a port range of just 1

// at the given port offset; i.e. a NetworkAddress that

// represents precisely 1 address only.

func (na NetworkAddress) At(portOffset uint) NetworkAddress {

na2 := na

na2.StartPort, na2.EndPort = na.StartPort+portOffset, na.StartPort+portOffset

return na2

}

// PortRangeSize returns how many ports are in

// pa's port range. Port ranges are inclusive,

// so the size is the difference of start and

// end ports plus one.

func (na NetworkAddress) PortRangeSize() uint {

if na.EndPort < na.StartPort {

return 0

}

return (na.EndPort - na.StartPort) + 1

}

func (na NetworkAddress) isLoopback() bool {

if na.IsUnixNetwork() {

return true

}

if na.Host == "localhost" {

return true

}

if ip, err := netip.ParseAddr(na.Host); err == nil {

return ip.IsLoopback()

}

return false

}

func (na NetworkAddress) isWildcardInterface() bool {

if na.Host == "" {

return true

}

if ip, err := netip.ParseAddr(na.Host); err == nil {

return ip.IsUnspecified()

}

return false

}

func (na NetworkAddress) port() string {

if na.StartPort == na.EndPort {

return strconv.FormatUint(uint64(na.StartPort), 10)

}

return fmt.Sprintf("%d-%d", na.StartPort, na.EndPort)

}

// String reconstructs the address string for human display.

// The output can be parsed by ParseNetworkAddress(). If the

// address is a unix socket, any non-zero port will be dropped.

func (na NetworkAddress) String() string {

if na.Network == "tcp" && (na.Host != "" || na.port() != "") {

na.Network = "" // omit default network value for brevity

}

return JoinNetworkAddress(na.Network, na.Host, na.port())

}

func isUnixNetwork(netw string) bool {

return netw == "unix" || netw == "unixgram" || netw == "unixpacket"

}

// ParseNetworkAddress parses addr into its individual

// components. The input string is expected to be of

// the form "network/host:port-range" where any part is

// optional. The default network, if unspecified, is tcp.

// Port ranges are inclusive.

// Network addresses are distinct from URLs and do not

// use URL syntax.

func ParseNetworkAddress(addr string) (NetworkAddress, error) {

var host, port string

network, host, port, err := SplitNetworkAddress(addr)

if err != nil {

return NetworkAddress{}, err

}

if network == "" {

network = "tcp"

}

if isUnixNetwork(network) {

return NetworkAddress{

Network: network,

Host: host,

}, nil

}

var start, end uint64

if port != "" {

before, after, found := strings.Cut(port, "-")

if !found {

after = before

}

start, err = strconv.ParseUint(before, 10, 16)

if err != nil {

return NetworkAddress{}, fmt.Errorf("invalid start port: %v", err)

}

end, err = strconv.ParseUint(after, 10, 16)

if err != nil {

return NetworkAddress{}, fmt.Errorf("invalid end port: %v", err)

}

if end < start {

return NetworkAddress{}, fmt.Errorf("end port must not be less than start port")

}

if (end - start) > maxPortSpan {

return NetworkAddress{}, fmt.Errorf("port range exceeds %d ports", maxPortSpan)

}

return NetworkAddress{

Network: network,

Host: host,

StartPort: uint(start),

EndPort: uint(end),

}, nil

}

// SplitNetworkAddress splits a into its network, host, and port components.

// Note that port may be a port range (:X-Y), or omitted for unix sockets.

func SplitNetworkAddress(a string) (network, host, port string, err error) {

beforeSlash, afterSlash, slashFound := strings.Cut(a, "/")

if slashFound {

network = strings.ToLower(strings.TrimSpace(beforeSlash))

a = afterSlash

}

if isUnixNetwork(network) {

host = a

return

}

host, port, err = net.SplitHostPort(a)

if err == nil || a == "" {

return

}

// in general, if there was an error, it was likely "missing port",

// so try adding a bogus port to take advantage of standard library's

// robust parser, then strip the artificial port before returning

// (don't overwrite original error though; might still be relevant)

var err2 error

host, port, err2 = net.SplitHostPort(a + ":0")

if err2 == nil {

err = nil

port = ""

}

return

}

// JoinNetworkAddress combines network, host, and port into a single

// address string of the form accepted by ParseNetworkAddress(). For

// unix sockets, the network should be "unix" (or "unixgram" or

// "unixpacket") and the path to the socket should be given as the

// host parameter.

func JoinNetworkAddress(network, host, port string) string {

var a string

if network != "" {

a = network + "/"

}

if (host != "" && port == "") || isUnixNetwork(network) {

a += host

} else if port != "" {

a += net.JoinHostPort(host, port)

}

return a

}

// DEPRECATED: Use NetworkAddress.Listen instead. This function will likely be changed or removed in the future.

func Listen(network, addr string) (net.Listener, error) {

// a 0 timeout means Go uses its default

return ListenTimeout(network, addr, 0)

}

// DEPRECATED: Use NetworkAddress.Listen instead. This function will likely be changed or removed in the future.

func ListenTimeout(network, addr string, keepalivePeriod time.Duration) (net.Listener, error) {

netAddr, err := ParseNetworkAddress(JoinNetworkAddress(network, addr, ""))

if err != nil {

return nil, err

}

ln, err := netAddr.Listen(context.TODO(), 0, net.ListenConfig{KeepAlive: keepalivePeriod})

if err != nil {

return nil, err

}

return ln.(net.Listener), nil

}

// DEPRECATED: Use NetworkAddress.Listen instead. This function will likely be changed or removed in the future.

func ListenPacket(network, addr string) (net.PacketConn, error) {

netAddr, err := ParseNetworkAddress(JoinNetworkAddress(network, addr, ""))

if err != nil {

return nil, err

}

ln, err := netAddr.Listen(context.TODO(), 0, net.ListenConfig{})

if err != nil {

return nil, err

}

return ln.(net.PacketConn), nil

}

// ListenQUIC returns a quic.EarlyListener suitable for use in a Caddy module.

// The network will be transformed into a QUIC-compatible type (if unix, then

// unixgram will be used; otherwise, udp will be used).

// NOTE: This API is EXPERIMENTAL and may be changed or removed.

// TODO: See if we can find a more elegant solution closer to the new NetworkAddress.Listen API.

func ListenQUIC(ln net.PacketConn, tlsConf *tls.Config, activeRequests *int64) (quic.EarlyListener, error) {

lnKey := listenerKey("quic+"+ln.LocalAddr().Network(), ln.LocalAddr().String())

sharedEarlyListener, _, err := listenerPool.LoadOrNew(lnKey, func() (Destructor, error) {

earlyLn, err := quic.ListenEarly(ln, http3.ConfigureTLSConfig(tlsConf), &quic.Config{

RequireAddressValidation: func(clientAddr net.Addr) bool {

var highLoad bool

if activeRequests != nil {

highLoad = atomic.LoadInt64(activeRequests) > 1000 // TODO: make tunable?

}

return highLoad

})

if err != nil {

return nil, err

}

return &sharedQuicListener{EarlyListener: earlyLn, key: lnKey}, nil

})

if err != nil {

return nil, err

}

// TODO: to serve QUIC over a unix socket, currently we need to hold onto

// the underlying net.PacketConn (which we wrap as unixConn to keep count

// of closes) because closing the quic.EarlyListener doesn't actually close

// the underlying PacketConn, but we need to for unix sockets since we dup

// the file descriptor and thus need to close the original; track issue:

// https://github.com/lucas-clemente/quic-go/issues/3560#issuecomment-1258959608

var unix *unixConn

if uc, ok := ln.(*unixConn); ok {

unix = uc

}

ctx, cancel := context.WithCancel(context.Background())

return &fakeCloseQuicListener{

sharedQuicListener: sharedEarlyListener.(*sharedQuicListener),

uc: unix,

context: ctx,

contextCancel: cancel,

}, nil

}

// ListenerUsage returns the current usage count of the given listener address.

func ListenerUsage(network, addr string) int {

count, _ := listenerPool.References(listenerKey(network, addr))

return count

}

// sharedQuicListener is like sharedListener, but for quic.EarlyListeners.

type sharedQuicListener struct {

quic.EarlyListener

key string

}

// Destruct closes the underlying QUIC listener.

func (sql *sharedQuicListener) Destruct() error {

return sql.EarlyListener.Close()

}

// sharedPacketConn is like sharedListener, but for net.PacketConns.

type sharedPacketConn struct {

net.PacketConn

key string

}

// Destruct closes the underlying socket.

func (spc *sharedPacketConn) Destruct() error {

return spc.PacketConn.Close()

}

// fakeClosedErr returns an error value that is not temporary

// nor a timeout, suitable for making the caller think the

// listener is actually closed

func fakeClosedErr(l interface{ Addr() net.Addr }) error {

return &net.OpError{

Op: "accept",

Net: l.Addr().Network(),

Addr: l.Addr(),

Err: errFakeClosed,

}

// errFakeClosed is the underlying error value returned by

// fakeCloseListener.Accept() after Close() has been called,

// indicating that it is pretending to be closed so that the

// server using it can terminate, while the underlying

// socket is actually left open.

var errFakeClosed = fmt.Errorf("listener 'closed' 😉")

// fakeClosePacketConn is like fakeCloseListener, but for PacketConns.

type fakeClosePacketConn struct {

closed int32 // accessed atomically; belongs to this struct only

*sharedPacketConn // embedded, so we also become a net.PacketConn

}

func (fcpc *fakeClosePacketConn) Close() error {

if atomic.CompareAndSwapInt32(&fcpc.closed, 0, 1) {

_, _ = listenerPool.Delete(fcpc.sharedPacketConn.key)

}

return nil

}

// Supports QUIC implementation: https://github.com/caddyserver/caddy/issues/3998

func (fcpc fakeClosePacketConn) SetReadBuffer(bytes int) error {

if conn, ok := fcpc.PacketConn.(interface{ SetReadBuffer(int) error }); ok {

return conn.SetReadBuffer(bytes)

}

return fmt.Errorf("SetReadBuffer() not implemented for %T", fcpc.PacketConn)

}

// Supports QUIC implementation: https://github.com/caddyserver/caddy/issues/3998

func (fcpc fakeClosePacketConn) SyscallConn() (syscall.RawConn, error) {

if conn, ok := fcpc.PacketConn.(interface {

SyscallConn() (syscall.RawConn, error)

}); ok {

return conn.SyscallConn()

}

return nil, fmt.Errorf("SyscallConn() not implemented for %T", fcpc.PacketConn)

}

type fakeCloseQuicListener struct {

closed int32 // accessed atomically; belongs to this struct only

*sharedQuicListener // embedded, so we also become a quic.EarlyListener

uc *unixConn // underlying unix socket, if UDS

context context.Context

contextCancel context.CancelFunc

}

// Currently Accept ignores the passed context, however a situation where

// someone would need a hotswappable QUIC-only (not http3, since it uses context.Background here)

// server on which Accept would be called with non-empty contexts

// (mind that the default net listeners' Accept doesn't take a context argument)

// sounds way too rare for us to sacrifice efficiency here.

func (fcql *fakeCloseQuicListener) Accept(_ context.Context) (quic.EarlyConnection, error) {

conn, err := fcql.sharedQuicListener.Accept(fcql.context)

if err == nil {

return conn, nil

}

// if the listener is "closed", return a fake closed error instead

if atomic.LoadInt32(&fcql.closed) == 1 && errors.Is(err, context.Canceled) {

return nil, fakeClosedErr(fcql)

}

return nil, err

}

func (fcql *fakeCloseQuicListener) Close() error {

if atomic.CompareAndSwapInt32(&fcql.closed, 0, 1) {

fcql.contextCancel()

_, _ = listenerPool.Delete(fcql.sharedQuicListener.key)

if fcql.uc != nil {

// unix sockets need to be closed ourselves because we dup() the file

// descriptor when we reuse them, so this avoids a resource leak

fcql.uc.Close()

}

return nil

}

// RegisterNetwork registers a network type with Caddy so that if a listener is

// created for that network type, getListener will be invoked to get the listener.

// This should be called during init() and will panic if the network type is standard

// or reserved, or if it is already registered. EXPERIMENTAL and subject to change.

func RegisterNetwork(network string, getListener ListenerFunc) {

network = strings.TrimSpace(strings.ToLower(network))

if network == "tcp" || network == "tcp4" || network == "tcp6" ||

network == "udp" || network == "udp4" || network == "udp6" ||

network == "unix" || network == "unixpacket" || network == "unixgram" ||

strings.HasPrefix("ip:", network) || strings.HasPrefix("ip4:", network) || strings.HasPrefix("ip6:", network) {

panic("network type " + network + " is reserved")

}

if _, ok := networkTypes[strings.ToLower(network)]; ok {

panic("network type " + network + " is already registered")

}

networkTypes[network] = getListener

}

type unixListener struct {

*net.UnixListener

mapKey string

count *int32 // accessed atomically

}

func (uln *unixListener) Close() error {

newCount := atomic.AddInt32(uln.count, -1)

if newCount == 0 {

defer func() {

addr := uln.Addr().String()

unixSocketsMu.Lock()

delete(unixSockets, uln.mapKey)

unixSocketsMu.Unlock()

_ = syscall.Unlink(addr)

}()

}

return uln.UnixListener.Close()

}

type unixConn struct {

*net.UnixConn

filename string

mapKey string

count *int32 // accessed atomically

}

func (uc *unixConn) Close() error {

newCount := atomic.AddInt32(uc.count, -1)

if newCount == 0 {

defer func() {

unixSocketsMu.Lock()

delete(unixSockets, uc.mapKey)

unixSocketsMu.Unlock()

_ = syscall.Unlink(uc.filename)

}()

}

return uc.UnixConn.Close()

}

// unixSockets keeps track of the currently-active unix sockets

// so we can transfer their FDs gracefully during reloads.

var (

unixSockets = make(map[string]interface {

File() (*os.File, error)

})

unixSocketsMu sync.Mutex

)

// getListenerFromPlugin returns a listener on the given network and address

// if a plugin has registered the network name. It may return (nil, nil) if

// no plugin can provide a listener.

func getListenerFromPlugin(ctx context.Context, network, addr string, config net.ListenConfig) (any, error) {

// get listener from plugin if network type is registered

if getListener, ok := networkTypes[network]; ok {

Log().Debug("getting listener from plugin", zap.String("network", network))

return getListener(ctx, network, addr, config)

}

return nil, nil

}

func listenerKey(network, addr string) string {

return network + "/" + addr

}

// ListenerFunc is a function that can return a listener given a network and address.

// The listeners must be capable of overlapping: with Caddy, new configs are loaded

// before old ones are unloaded, so listeners may overlap briefly if the configs

// both need the same listener. EXPERIMENTAL and subject to change.

type ListenerFunc func(ctx context.Context, network, addr string, cfg net.ListenConfig) (any, error)

var networkTypes = map[string]ListenerFunc{}

// ListenerWrapper is a type that wraps a listener

// so it can modify the input listener's methods.

// Modules that implement this interface are found

// in the caddy.listeners namespace. Usually, to

// wrap a listener, you will define your own struct

// type that embeds the input listener, then

// implement your own methods that you want to wrap,

// calling the underlying listener's methods where

// appropriate.

type ListenerWrapper interface {

WrapListener(net.Listener) net.Listener

}

// listenerPool stores and allows reuse of active listeners.

var listenerPool = NewUsagePool()

const maxPortSpan = 65535

// Interface guards (see https://github.com/caddyserver/caddy/issues/3998)

var (

_ (interface{ SetReadBuffer(int) error }) = (*fakeClosePacketConn)(nil)

_ (interface {

SyscallConn() (syscall.RawConn, error)

}) = (*fakeClosePacketConn)(nil)

)

caddy/listeners.go at master · bit/caddy · GitHub

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