violet/proxy/reverse-proxy.go

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2023-04-19 01:30:23 +01:00
package proxy
import (
"context"
"crypto/tls"
"errors"
"fmt"
"golang.org/x/net/proxy"
"log"
"net"
"net/http"
"net/http/httputil"
"sync"
"time"
)
type reverseProxyHostKey int
type ReverseProxyContext interface {
IsIgnoreCert() bool
UpdateHeaders(http.Header)
}
func SetReverseProxyHost(req *http.Request, hf ReverseProxyContext) *http.Request {
ctx := req.Context()
ctx2 := context.WithValue(ctx, reverseProxyHostKey(0), hf)
return req.WithContext(ctx2)
}
func CreateHybridReverseProxy() *httputil.ReverseProxy {
return &httputil.ReverseProxy{
Director: func(req *http.Request) {},
Transport: NewHybridTransport(),
ModifyResponse: func(rw *http.Response) error { return nil },
ErrorHandler: func(rw http.ResponseWriter, req *http.Request, err error) {
log.Printf("[ReverseProxy] Request: %#v\n -- Error: %s\n", req, err)
rw.WriteHeader(http.StatusBadGateway)
_, _ = rw.Write([]byte("502 Bad gateway\n"))
},
}
}
type HybridTransport struct {
baseDialer *net.Dialer
normalTransport http.RoundTripper
insecureTransport http.RoundTripper
socksSync *sync.RWMutex
socksTransport map[string]http.RoundTripper
}
func NewHybridTransport() *HybridTransport {
h := &HybridTransport{
baseDialer: &net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
},
socksSync: &sync.RWMutex{},
socksTransport: make(map[string]http.RoundTripper),
}
h.normalTransport = &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: h.baseDialer.DialContext,
ForceAttemptHTTP2: true,
MaxIdleConns: 15,
TLSHandshakeTimeout: 10 * time.Second,
IdleConnTimeout: 30 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
ResponseHeaderTimeout: 10 * time.Second,
}
h.insecureTransport = &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: h.baseDialer.DialContext,
ForceAttemptHTTP2: true,
MaxIdleConns: 15,
TLSHandshakeTimeout: 10 * time.Second,
IdleConnTimeout: 30 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
ResponseHeaderTimeout: 10 * time.Second,
TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
}
return h
}
func (h *HybridTransport) RoundTrip(req *http.Request) (*http.Response, error) {
newHost := req.Context().Value(reverseProxyHostKey(0))
hf, ok := newHost.(ReverseProxyContext)
if !ok {
return nil, errors.New("failed to detect reverse proxy configuration")
}
// Do a round trip using existing transports
var trip *http.Response
var err error
if hf.IsIgnoreCert() {
trip, err = h.insecureTransport.RoundTrip(req)
} else {
trip, err = h.normalTransport.RoundTrip(req)
}
if err != nil {
return nil, err
}
// Override headers
hf.UpdateHeaders(trip.Header)
return trip, nil
}
func (h *HybridTransport) getSocksProxy(addr string, insecure bool) (http.RoundTripper, error) {
if insecure {
addr = "%i-" + addr
}
h.socksSync.RLock()
s, ok := h.socksTransport[addr]
h.socksSync.RUnlock()
if ok {
return s, nil
}
dialer, err := proxy.SOCKS5("tcp", addr, nil, proxy.Direct)
if err != nil {
return nil, fmt.Errorf("cannot connect to the proxy: %s", err)
}
if f, ok := dialer.(proxy.ContextDialer); ok {
t := &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: f.DialContext,
ForceAttemptHTTP2: true,
MaxIdleConns: 15,
TLSHandshakeTimeout: 10 * time.Second,
IdleConnTimeout: 30 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
ResponseHeaderTimeout: 10 * time.Second,
DisableKeepAlives: true,
}
if insecure {
t.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
}
h.socksSync.Lock()
h.socksTransport[addr] = t
h.socksSync.Unlock()
return t, nil
}
return nil, errors.New("cannot create socks5 dialer")
}