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// Copyright 2015 Matthew Holt and The Caddy Authors
//
// 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 reverseproxy
import (
"context"
"crypto/tls"
"crypto/x509"
"encoding/base64"
"fmt"
"net"
"net/http"
"reflect"
"time"
"github.com/caddyserver/caddy/v2"
)
func init() {
caddy.RegisterModule(HTTPTransport{})
}
// HTTPTransport is essentially a configuration wrapper for http.Transport.
// It defines a JSON structure useful when configuring the HTTP transport
// for Caddy's reverse proxy.
type HTTPTransport struct {
// TODO: It's possible that other transports (like fastcgi) might be
// able to borrow/use at least some of these config fields; if so,
// move them into a type called CommonTransport and embed it
TLS *TLSConfig `json:"tls,omitempty"`
KeepAlive *KeepAlive `json:"keep_alive,omitempty"`
Compression *bool `json:"compression,omitempty"`
MaxConnsPerHost int `json:"max_conns_per_host,omitempty"` // TODO: NOTE: we use our health check stuff to enforce max REQUESTS per host, but this is connections
DialTimeout caddy.Duration `json:"dial_timeout,omitempty"`
FallbackDelay caddy.Duration `json:"dial_fallback_delay,omitempty"`
ResponseHeaderTimeout caddy.Duration `json:"response_header_timeout,omitempty"`
ExpectContinueTimeout caddy.Duration `json:"expect_continue_timeout,omitempty"`
MaxResponseHeaderSize int64 `json:"max_response_header_size,omitempty"`
WriteBufferSize int `json:"write_buffer_size,omitempty"`
ReadBufferSize int `json:"read_buffer_size,omitempty"`
RoundTripper http.RoundTripper `json:"-"`
}
// CaddyModule returns the Caddy module information.
func (HTTPTransport) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
Name: "http.handlers.reverse_proxy.transport.http",
New: func() caddy.Module { return new(HTTPTransport) },
}
}
// Provision sets up h.RoundTripper with a http.Transport
// that is ready to use.
func (h *HTTPTransport) Provision(_ caddy.Context) error {
dialer := &net.Dialer{
Timeout: time.Duration(h.DialTimeout),
FallbackDelay: time.Duration(h.FallbackDelay),
// TODO: Resolver
}
rt := &http.Transport{
DialContext: func(ctx context.Context, network, address string) (net.Conn, error) {
// the proper dialing information should be embedded into the request's context
if dialInfoVal := ctx.Value(DialInfoCtxKey); dialInfoVal != nil {
dialInfo := dialInfoVal.(DialInfo)
network = dialInfo.Network
address = dialInfo.Address
}
return dialer.DialContext(ctx, network, address)
},
MaxConnsPerHost: h.MaxConnsPerHost,
ResponseHeaderTimeout: time.Duration(h.ResponseHeaderTimeout),
ExpectContinueTimeout: time.Duration(h.ExpectContinueTimeout),
MaxResponseHeaderBytes: h.MaxResponseHeaderSize,
WriteBufferSize: h.WriteBufferSize,
ReadBufferSize: h.ReadBufferSize,
}
if h.TLS != nil {
rt.TLSHandshakeTimeout = time.Duration(h.TLS.HandshakeTimeout)
var err error
rt.TLSClientConfig, err = h.TLS.MakeTLSClientConfig()
if err != nil {
return fmt.Errorf("making TLS client config: %v", err)
}
}
if h.KeepAlive != nil {
dialer.KeepAlive = time.Duration(h.KeepAlive.ProbeInterval)
if enabled := h.KeepAlive.Enabled; enabled != nil {
rt.DisableKeepAlives = !*enabled
}
rt.MaxIdleConns = h.KeepAlive.MaxIdleConns
rt.MaxIdleConnsPerHost = h.KeepAlive.MaxIdleConnsPerHost
rt.IdleConnTimeout = time.Duration(h.KeepAlive.IdleConnTimeout)
}
if h.Compression != nil {
rt.DisableCompression = !*h.Compression
}
h.RoundTripper = rt
return nil
}
// RoundTrip implements http.RoundTripper with h.RoundTripper.
func (h HTTPTransport) RoundTrip(req *http.Request) (*http.Response, error) {
return h.RoundTripper.RoundTrip(req)
}
// TLSConfig holds configuration related to the
// TLS configuration for the transport/client.
type TLSConfig struct {
RootCAPool []string `json:"root_ca_pool,omitempty"`
// TODO: Should the client cert+key config use caddytls.CertificateLoader modules?
ClientCertificateFile string `json:"client_certificate_file,omitempty"`
ClientCertificateKeyFile string `json:"client_certificate_key_file,omitempty"`
InsecureSkipVerify bool `json:"insecure_skip_verify,omitempty"`
HandshakeTimeout caddy.Duration `json:"handshake_timeout,omitempty"`
}
// MakeTLSClientConfig returns a tls.Config usable by a client to a backend.
// If there is no custom TLS configuration, a nil config may be returned.
func (t TLSConfig) MakeTLSClientConfig() (*tls.Config, error) {
cfg := new(tls.Config)
// client auth
if t.ClientCertificateFile != "" && t.ClientCertificateKeyFile == "" {
return nil, fmt.Errorf("client_certificate_file specified without client_certificate_key_file")
}
if t.ClientCertificateFile == "" && t.ClientCertificateKeyFile != "" {
return nil, fmt.Errorf("client_certificate_key_file specified without client_certificate_file")
}
if t.ClientCertificateFile != "" && t.ClientCertificateKeyFile != "" {
cert, err := tls.LoadX509KeyPair(t.ClientCertificateFile, t.ClientCertificateKeyFile)
if err != nil {
return nil, fmt.Errorf("loading client certificate key pair: %v", err)
}
cfg.Certificates = []tls.Certificate{cert}
}
// trusted root CAs
if len(t.RootCAPool) > 0 {
rootPool := x509.NewCertPool()
for _, encodedCACert := range t.RootCAPool {
caCert, err := decodeBase64DERCert(encodedCACert)
if err != nil {
return nil, fmt.Errorf("parsing CA certificate: %v", err)
}
rootPool.AddCert(caCert)
}
cfg.RootCAs = rootPool
}
// throw all security out the window
cfg.InsecureSkipVerify = t.InsecureSkipVerify
// only return a config if it's not empty
if reflect.DeepEqual(cfg, new(tls.Config)) {
return nil, nil
}
cfg.NextProtos = []string{"h2", "http/1.1"} // TODO: ensure that this actually enables HTTP/2
return cfg, nil
}
// decodeBase64DERCert base64-decodes, then DER-decodes, certStr.
func decodeBase64DERCert(certStr string) (*x509.Certificate, error) {
// decode base64
derBytes, err := base64.StdEncoding.DecodeString(certStr)
if err != nil {
return nil, err
}
// parse the DER-encoded certificate
return x509.ParseCertificate(derBytes)
}
// KeepAlive holds configuration pertaining to HTTP Keep-Alive.
type KeepAlive struct {
Enabled *bool `json:"enabled,omitempty"`
ProbeInterval caddy.Duration `json:"probe_interval,omitempty"`
MaxIdleConns int `json:"max_idle_conns,omitempty"`
MaxIdleConnsPerHost int `json:"max_idle_conns_per_host,omitempty"`
IdleConnTimeout caddy.Duration `json:"idle_timeout,omitempty"` // how long should connections be kept alive when idle
}
// Interface guards
var (
_ caddy.Provisioner = (*HTTPTransport)(nil)
_ http.RoundTripper = (*HTTPTransport)(nil)
)
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