traefik/pkg/tcp/router.go

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package tcp
import (
"bufio"
"bytes"
"crypto/tls"
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"errors"
"io"
"net"
"net/http"
"strings"
"time"
"github.com/traefik/traefik/v2/pkg/log"
"github.com/traefik/traefik/v2/pkg/types"
)
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// Router is a TCP router.
type Router struct {
routingTable map[string]Handler
httpForwarder Handler
httpsForwarder Handler
httpHandler http.Handler
httpsHandler http.Handler
httpsTLSConfig *tls.Config // default TLS config
catchAllNoTLS Handler
hostHTTPTLSConfig map[string]*tls.Config // TLS configs keyed by SNI
}
// GetTLSGetClientInfo is called after a ClientHello is received from a client.
func (r *Router) GetTLSGetClientInfo() func(info *tls.ClientHelloInfo) (*tls.Config, error) {
return func(info *tls.ClientHelloInfo) (*tls.Config, error) {
if tlsConfig, ok := r.hostHTTPTLSConfig[info.ServerName]; ok {
return tlsConfig, nil
}
return r.httpsTLSConfig, nil
}
}
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// ServeTCP forwards the connection to the right TCP/HTTP handler.
func (r *Router) ServeTCP(conn WriteCloser) {
// FIXME -- Check if ProxyProtocol changes the first bytes of the request
if r.catchAllNoTLS != nil && len(r.routingTable) == 0 {
r.catchAllNoTLS.ServeTCP(conn)
return
}
br := bufio.NewReader(conn)
serverName, tls, peeked, err := clientHelloServerName(br)
if err != nil {
conn.Close()
return
}
// Remove read/write deadline and delegate this to underlying tcp server (for now only handled by HTTP Server)
err = conn.SetReadDeadline(time.Time{})
if err != nil {
log.WithoutContext().Errorf("Error while setting read deadline: %v", err)
}
err = conn.SetWriteDeadline(time.Time{})
if err != nil {
log.WithoutContext().Errorf("Error while setting write deadline: %v", err)
}
if !tls {
switch {
case r.catchAllNoTLS != nil:
r.catchAllNoTLS.ServeTCP(r.GetConn(conn, peeked))
case r.httpForwarder != nil:
r.httpForwarder.ServeTCP(r.GetConn(conn, peeked))
default:
conn.Close()
}
return
}
// FIXME Optimize and test the routing table before helloServerName
serverName = types.CanonicalDomain(serverName)
if r.routingTable != nil && serverName != "" {
if target, ok := r.routingTable[serverName]; ok {
target.ServeTCP(r.GetConn(conn, peeked))
return
}
}
// FIXME Needs tests
if target, ok := r.routingTable["*"]; ok {
target.ServeTCP(r.GetConn(conn, peeked))
return
}
if r.httpsForwarder != nil {
r.httpsForwarder.ServeTCP(r.GetConn(conn, peeked))
} else {
conn.Close()
}
}
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// AddRoute defines a handler for a given sniHost (* is the only valid option).
func (r *Router) AddRoute(sniHost string, target Handler) {
if r.routingTable == nil {
r.routingTable = map[string]Handler{}
}
r.routingTable[strings.ToLower(sniHost)] = target
}
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// AddRouteTLS defines a handler for a given sniHost and sets the matching tlsConfig.
func (r *Router) AddRouteTLS(sniHost string, target Handler, config *tls.Config) {
r.AddRoute(sniHost, &TLSHandler{
Next: target,
Config: config,
})
}
// AddRouteHTTPTLS defines a handler for a given sniHost and sets the matching tlsConfig.
func (r *Router) AddRouteHTTPTLS(sniHost string, config *tls.Config) {
if r.hostHTTPTLSConfig == nil {
r.hostHTTPTLSConfig = map[string]*tls.Config{}
}
r.hostHTTPTLSConfig[sniHost] = config
}
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// AddCatchAllNoTLS defines the fallback tcp handler.
func (r *Router) AddCatchAllNoTLS(handler Handler) {
r.catchAllNoTLS = handler
}
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// GetConn creates a connection proxy with a peeked string.
func (r *Router) GetConn(conn WriteCloser, peeked string) WriteCloser {
// FIXME should it really be on Router ?
conn = &Conn{
Peeked: []byte(peeked),
WriteCloser: conn,
}
return conn
}
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// GetHTTPHandler gets the attached http handler.
func (r *Router) GetHTTPHandler() http.Handler {
return r.httpHandler
}
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// GetHTTPSHandler gets the attached https handler.
func (r *Router) GetHTTPSHandler() http.Handler {
return r.httpsHandler
}
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// HTTPForwarder sets the tcp handler that will forward the connections to an http handler.
func (r *Router) HTTPForwarder(handler Handler) {
r.httpForwarder = handler
}
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// HTTPSForwarder sets the tcp handler that will forward the TLS connections to an http handler.
func (r *Router) HTTPSForwarder(handler Handler) {
for sniHost, tlsConf := range r.hostHTTPTLSConfig {
r.AddRouteTLS(sniHost, handler, tlsConf)
}
r.httpsForwarder = &TLSHandler{
Next: handler,
Config: r.httpsTLSConfig,
}
}
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// HTTPHandler attaches http handlers on the router.
func (r *Router) HTTPHandler(handler http.Handler) {
r.httpHandler = handler
}
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// HTTPSHandler attaches https handlers on the router.
func (r *Router) HTTPSHandler(handler http.Handler, config *tls.Config) {
r.httpsHandler = handler
r.httpsTLSConfig = config
}
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// Conn is a connection proxy that handles Peeked bytes.
type Conn struct {
// Peeked are the bytes that have been read from Conn for the
// purposes of route matching, but have not yet been consumed
// by Read calls. It set to nil by Read when fully consumed.
Peeked []byte
// Conn is the underlying connection.
// It can be type asserted against *net.TCPConn or other types
// as needed. It should not be read from directly unless
// Peeked is nil.
WriteCloser
}
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// Read reads bytes from the connection (using the buffer prior to actually reading).
func (c *Conn) Read(p []byte) (n int, err error) {
if len(c.Peeked) > 0 {
n = copy(p, c.Peeked)
c.Peeked = c.Peeked[n:]
if len(c.Peeked) == 0 {
c.Peeked = nil
}
return n, nil
}
return c.WriteCloser.Read(p)
}
// clientHelloServerName returns the SNI server name inside the TLS ClientHello,
// without consuming any bytes from br.
// On any error, the empty string is returned.
func clientHelloServerName(br *bufio.Reader) (string, bool, string, error) {
hdr, err := br.Peek(1)
if err != nil {
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var opErr *net.OpError
if !errors.Is(err, io.EOF) && (!errors.As(err, &opErr) || opErr.Timeout()) {
log.WithoutContext().Debugf("Error while Peeking first byte: %s", err)
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}
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return "", false, "", err
}
// No valid TLS record has a type of 0x80, however SSLv2 handshakes
// start with a uint16 length where the MSB is set and the first record
// is always < 256 bytes long. Therefore typ == 0x80 strongly suggests
// an SSLv2 client.
const recordTypeSSLv2 = 0x80
const recordTypeHandshake = 0x16
if hdr[0] != recordTypeHandshake {
if hdr[0] == recordTypeSSLv2 {
// we consider SSLv2 as TLS and it will be refuse by real TLS handshake.
return "", true, getPeeked(br), nil
}
return "", false, getPeeked(br), nil // Not TLS.
}
const recordHeaderLen = 5
hdr, err = br.Peek(recordHeaderLen)
if err != nil {
log.Errorf("Error while Peeking hello: %s", err)
return "", false, getPeeked(br), nil
}
recLen := int(hdr[3])<<8 | int(hdr[4]) // ignoring version in hdr[1:3]
helloBytes, err := br.Peek(recordHeaderLen + recLen)
if err != nil {
log.Errorf("Error while Hello: %s", err)
return "", true, getPeeked(br), nil
}
sni := ""
server := tls.Server(sniSniffConn{r: bytes.NewReader(helloBytes)}, &tls.Config{
GetConfigForClient: func(hello *tls.ClientHelloInfo) (*tls.Config, error) {
sni = hello.ServerName
return nil, nil
},
})
_ = server.Handshake()
return sni, true, getPeeked(br), nil
}
func getPeeked(br *bufio.Reader) string {
peeked, err := br.Peek(br.Buffered())
if err != nil {
log.Errorf("Could not get anything: %s", err)
return ""
}
return string(peeked)
}
// sniSniffConn is a net.Conn that reads from r, fails on Writes,
// and crashes otherwise.
type sniSniffConn struct {
r io.Reader
net.Conn // nil; crash on any unexpected use
}
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// Read reads from the underlying reader.
func (c sniSniffConn) Read(p []byte) (int, error) { return c.r.Read(p) }
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// Write crashes all the time.
func (sniSniffConn) Write(p []byte) (int, error) { return 0, io.EOF }