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proxy.go
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proxy.go
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package proxy
import (
"bufio"
"crypto/tls"
"encoding/base64"
"fmt"
"net"
"net/http"
"net/url"
"strings"
"time"
"github.com/VictoriaMetrics/fasthttp"
"github.com/cprobe/cprobe/lib/logger"
"github.com/cprobe/cprobe/lib/promauth"
"golang.org/x/net/proxy"
)
var validURLSchemes = []string{"http", "https", "socks5", "tls+socks5"}
func isURLSchemeValid(scheme string) bool {
for _, vs := range validURLSchemes {
if scheme == vs {
return true
}
}
return false
}
// URL implements YAML.Marshaler and yaml.Unmarshaler interfaces for url.URL.
type URL struct {
URL *url.URL
}
// MustNewURL returns new URL for the given u.
func MustNewURL(u string) *URL {
pu, err := url.Parse(u)
if err != nil {
logger.Panicf("BUG: cannot parse u=%q: %s", u, err)
}
return &URL{
URL: pu,
}
}
// GetURL return the underlying url.
func (u *URL) GetURL() *url.URL {
if u == nil || u.URL == nil {
return nil
}
return u.URL
}
// IsHTTPOrHTTPS returns true if u is http or https
func (u *URL) IsHTTPOrHTTPS() bool {
pu := u.GetURL()
if pu == nil {
return false
}
scheme := u.URL.Scheme
return scheme == "http" || scheme == "https"
}
// String returns string representation of u.
func (u *URL) String() string {
pu := u.GetURL()
if pu == nil {
return ""
}
return pu.String()
}
// SetHeaders sets headers to req according to u and ac configs.
func (u *URL) SetHeaders(ac *promauth.Config, req *http.Request) error {
ah, err := u.getAuthHeader(ac)
if err != nil {
return fmt.Errorf("cannot obtain Proxy-Authorization headers: %w", err)
}
if ah != "" {
req.Header.Set("Proxy-Authorization", ah)
}
return ac.SetHeaders(req, false)
}
// SetFasthttpHeaders sets headers to req according to u and ac configs.
func (u *URL) SetFasthttpHeaders(ac *promauth.Config, req *fasthttp.Request) error {
ah, err := u.getAuthHeader(ac)
if err != nil {
return fmt.Errorf("cannot obtain Proxy-Authorization headers: %w", err)
}
if ah != "" {
req.Header.Set("Proxy-Authorization", ah)
}
return ac.SetFasthttpHeaders(req, false)
}
// getAuthHeader returns Proxy-Authorization auth header for the given u and ac.
func (u *URL) getAuthHeader(ac *promauth.Config) (string, error) {
authHeader := ""
if ac != nil {
var err error
authHeader, err = ac.GetAuthHeader()
if err != nil {
return "", err
}
}
if u == nil || u.URL == nil {
return authHeader, nil
}
pu := u.URL
if pu.User != nil && len(pu.User.Username()) > 0 {
userPasswordEncoded := base64.StdEncoding.EncodeToString([]byte(pu.User.String()))
authHeader = "Basic " + userPasswordEncoded
}
return authHeader, nil
}
// MarshalYAML implements yaml.Marshaler interface.
func (u *URL) MarshalYAML() (interface{}, error) {
if u.URL == nil {
return nil, nil
}
return u.URL.String(), nil
}
// UnmarshalYAML implements yaml.Unmarshaler interface.
func (u *URL) UnmarshalYAML(unmarshal func(interface{}) error) error {
var s string
if err := unmarshal(&s); err != nil {
return err
}
parsedURL, err := url.Parse(s)
if err != nil {
return fmt.Errorf("cannot parse proxy_url=%q as *url.URL: %w", s, err)
}
if !isURLSchemeValid(parsedURL.Scheme) {
return fmt.Errorf("cannot parse proxy_url=%q unsupported scheme format=%q, valid schemes: %s", s, parsedURL.Scheme, validURLSchemes)
}
u.URL = parsedURL
return nil
}
func (u *URL) UnmarshalTOML(b []byte) error {
parsedURL, err := url.Parse(string(b))
if err != nil {
return fmt.Errorf("cannot parse proxy_url=%q as *url.URL: %w", string(b), err)
}
u.URL = parsedURL
return nil
}
func (u *URL) UnmarshalText(b []byte) error {
return u.UnmarshalTOML(b)
}
// NewDialFunc returns dial func for the given u and ac.
func (u *URL) NewDialFunc(ac *promauth.Config) (fasthttp.DialFunc, error) {
if u == nil || u.URL == nil {
return defaultDialFunc, nil
}
pu := u.URL
if !isURLSchemeValid(pu.Scheme) {
return nil, fmt.Errorf("unknown scheme=%q for proxy_url=%q, must be in %s", pu.Scheme, pu.Redacted(), validURLSchemes)
}
isTLS := (pu.Scheme == "https" || pu.Scheme == "tls+socks5")
proxyAddr := addMissingPort(pu.Host, isTLS)
var tlsCfg *tls.Config
if isTLS {
var err error
tlsCfg, err = ac.NewTLSConfig()
if err != nil {
return nil, fmt.Errorf("cannot initialize tls config: %w", err)
}
if !tlsCfg.InsecureSkipVerify && tlsCfg.ServerName == "" {
tlsCfg.ServerName = tlsServerName(proxyAddr)
}
}
if pu.Scheme == "socks5" || pu.Scheme == "tls+socks5" {
return socks5DialFunc(proxyAddr, pu, tlsCfg)
}
dialFunc := func(addr string) (net.Conn, error) {
proxyConn, err := defaultDialFunc(proxyAddr)
if err != nil {
return nil, fmt.Errorf("cannot connect to proxy %q: %w", pu.Redacted(), err)
}
if isTLS {
proxyConn = tls.Client(proxyConn, tlsCfg)
}
authHeader, err := u.getAuthHeader(ac)
if err != nil {
return nil, fmt.Errorf("cannot obtain Proxy-Authorization header: %w", err)
}
if authHeader != "" {
authHeader = "Proxy-Authorization: " + authHeader + "\r\n"
authHeader += ac.HeadersNoAuthString()
}
conn, err := sendConnectRequest(proxyConn, proxyAddr, addr, authHeader)
if err != nil {
_ = proxyConn.Close()
return nil, fmt.Errorf("error when sending CONNECT request to proxy %q: %w", pu.Redacted(), err)
}
return conn, nil
}
return dialFunc, nil
}
func socks5DialFunc(proxyAddr string, pu *url.URL, tlsCfg *tls.Config) (fasthttp.DialFunc, error) {
var sac *proxy.Auth
if pu.User != nil {
username := pu.User.Username()
password, _ := pu.User.Password()
sac = &proxy.Auth{
User: username,
Password: password,
}
}
// network := netutil.GetTCPNetwork()
network := "tcp"
var dialer proxy.Dialer = proxy.Direct
if tlsCfg != nil {
dialer = &tls.Dialer{
Config: tlsCfg,
}
}
d, err := proxy.SOCKS5(network, proxyAddr, sac, dialer)
if err != nil {
return nil, fmt.Errorf("cannot create socks5 proxy for url: %s, err: %w", pu.Redacted(), err)
}
dialFunc := func(addr string) (net.Conn, error) {
return d.Dial(network, addr)
}
return dialFunc, nil
}
func addMissingPort(addr string, isTLS bool) string {
if strings.IndexByte(addr, ':') >= 0 {
return addr
}
port := "80"
if isTLS {
port = "443"
}
return addr + ":" + port
}
func tlsServerName(addr string) string {
host, _, err := net.SplitHostPort(addr)
if err != nil {
return addr
}
return host
}
func defaultDialFunc(addr string) (net.Conn, error) {
// network := netutil.GetTCPNetwork()
network := "tcp"
// Do not use fasthttp.Dial because of https://github.com/VictoriaMetrics/VictoriaMetrics/issues/987
return net.DialTimeout(network, addr, 5*time.Second)
}
// sendConnectRequest sends CONNECT request to proxyConn for the given addr and authHeader and returns the established connection to dstAddr.
func sendConnectRequest(proxyConn net.Conn, proxyAddr, dstAddr, authHeader string) (net.Conn, error) {
req := "CONNECT " + dstAddr + " HTTP/1.1\r\nHost: " + proxyAddr + "\r\n" + authHeader + "\r\n"
if _, err := proxyConn.Write([]byte(req)); err != nil {
return nil, fmt.Errorf("cannot send CONNECT request for dstAddr=%q: %w", dstAddr, err)
}
var res fasthttp.Response
res.SkipBody = true
conn := &bufferedReaderConn{
br: bufio.NewReader(proxyConn),
Conn: proxyConn,
}
if err := res.Read(conn.br); err != nil {
return nil, fmt.Errorf("cannot read CONNECT response for dstAddr=%q: %w", dstAddr, err)
}
if statusCode := res.Header.StatusCode(); statusCode != 200 {
return nil, fmt.Errorf("unexpected status code received: %d; want: 200; response body: %q", statusCode, res.Body())
}
return conn, nil
}
type bufferedReaderConn struct {
net.Conn
br *bufio.Reader
}
func (brc *bufferedReaderConn) Read(p []byte) (int, error) {
return brc.br.Read(p)
}