cloudflare/cloudflared
Publicmirrored from https://github.com/cloudflare/cloudflaredAvailable
connection/http2.go
332lines · modecode
| 1 | package connection |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "fmt" |
| 6 | "io" |
| 7 | "math" |
| 8 | "net" |
| 9 | "net/http" |
| 10 | "strings" |
| 11 | "sync" |
| 12 | |
| 13 | "github.com/pkg/errors" |
| 14 | "github.com/rs/zerolog" |
| 15 | "golang.org/x/net/http2" |
| 16 | |
| 17 | tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs" |
| 18 | ) |
| 19 | |
| 20 | // note: these constants are exported so we can reuse them in the edge-side code |
| 21 | const ( |
| 22 | InternalUpgradeHeader = "Cf-Cloudflared-Proxy-Connection-Upgrade" |
| 23 | InternalTCPProxySrcHeader = "Cf-Cloudflared-Proxy-Src" |
| 24 | WebsocketUpgrade = "websocket" |
| 25 | ControlStreamUpgrade = "control-stream" |
| 26 | ) |
| 27 | |
| 28 | var errEdgeConnectionClosed = fmt.Errorf("connection with edge closed") |
| 29 | |
| 30 | // HTTP2Connection represents a net.Conn that uses HTTP2 frames to proxy traffic from the edge to cloudflared on the |
| 31 | // origin. |
| 32 | type HTTP2Connection struct { |
| 33 | conn net.Conn |
| 34 | server *http2.Server |
| 35 | config *Config |
| 36 | namedTunnel *NamedTunnelConfig |
| 37 | connOptions *tunnelpogs.ConnectionOptions |
| 38 | observer *Observer |
| 39 | connIndexStr string |
| 40 | connIndex uint8 |
| 41 | // newRPCClientFunc allows us to mock RPCs during testing |
| 42 | newRPCClientFunc func(context.Context, io.ReadWriteCloser, *zerolog.Logger) NamedTunnelRPCClient |
| 43 | |
| 44 | log *zerolog.Logger |
| 45 | activeRequestsWG sync.WaitGroup |
| 46 | connectedFuse ConnectedFuse |
| 47 | gracefulShutdownC <-chan struct{} |
| 48 | stoppedGracefully bool |
| 49 | controlStreamErr error // result of running control stream handler |
| 50 | } |
| 51 | |
| 52 | // NewHTTP2Connection returns a new instance of HTTP2Connection. |
| 53 | func NewHTTP2Connection( |
| 54 | conn net.Conn, |
| 55 | config *Config, |
| 56 | namedTunnelConfig *NamedTunnelConfig, |
| 57 | connOptions *tunnelpogs.ConnectionOptions, |
| 58 | observer *Observer, |
| 59 | connIndex uint8, |
| 60 | connectedFuse ConnectedFuse, |
| 61 | log *zerolog.Logger, |
| 62 | gracefulShutdownC <-chan struct{}, |
| 63 | ) *HTTP2Connection { |
| 64 | return &HTTP2Connection{ |
| 65 | conn: conn, |
| 66 | server: &http2.Server{ |
| 67 | MaxConcurrentStreams: math.MaxUint32, |
| 68 | }, |
| 69 | config: config, |
| 70 | namedTunnel: namedTunnelConfig, |
| 71 | connOptions: connOptions, |
| 72 | observer: observer, |
| 73 | connIndexStr: uint8ToString(connIndex), |
| 74 | connIndex: connIndex, |
| 75 | newRPCClientFunc: newRegistrationRPCClient, |
| 76 | connectedFuse: connectedFuse, |
| 77 | log: log, |
| 78 | gracefulShutdownC: gracefulShutdownC, |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | // Serve serves an HTTP2 server that the edge can talk to. |
| 83 | func (c *HTTP2Connection) Serve(ctx context.Context) error { |
| 84 | go func() { |
| 85 | <-ctx.Done() |
| 86 | c.close() |
| 87 | }() |
| 88 | c.server.ServeConn(c.conn, &http2.ServeConnOpts{ |
| 89 | Context: ctx, |
| 90 | Handler: c, |
| 91 | }) |
| 92 | |
| 93 | switch { |
| 94 | case c.stoppedGracefully: |
| 95 | return nil |
| 96 | case c.controlStreamErr != nil: |
| 97 | return c.controlStreamErr |
| 98 | default: |
| 99 | c.observer.log.Info().Uint8(LogFieldConnIndex, c.connIndex).Msg("Lost connection with the edge") |
| 100 | return errEdgeConnectionClosed |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | func (c *HTTP2Connection) ServeHTTP(w http.ResponseWriter, r *http.Request) { |
| 105 | c.activeRequestsWG.Add(1) |
| 106 | defer c.activeRequestsWG.Done() |
| 107 | |
| 108 | connType := determineHTTP2Type(r) |
| 109 | handleMissingRequestParts(connType, r) |
| 110 | |
| 111 | respWriter, err := newHTTP2RespWriter(r, w, connType) |
| 112 | if err != nil { |
| 113 | c.observer.log.Error().Msg(err.Error()) |
| 114 | return |
| 115 | } |
| 116 | |
| 117 | switch connType { |
| 118 | case TypeControlStream: |
| 119 | if err := c.serveControlStream(r.Context(), respWriter); err != nil { |
| 120 | c.controlStreamErr = err |
| 121 | c.log.Error().Err(err) |
| 122 | respWriter.WriteErrorResponse() |
| 123 | } |
| 124 | |
| 125 | case TypeWebsocket, TypeHTTP: |
| 126 | stripWebsocketUpgradeHeader(r) |
| 127 | if err := c.config.OriginProxy.ProxyHTTP(respWriter, r, connType == TypeWebsocket); err != nil { |
| 128 | err := fmt.Errorf("Failed to proxy HTTP: %w", err) |
| 129 | c.log.Error().Err(err) |
| 130 | respWriter.WriteErrorResponse() |
| 131 | } |
| 132 | |
| 133 | case TypeTCP: |
| 134 | host, err := getRequestHost(r) |
| 135 | if err != nil { |
| 136 | err := fmt.Errorf(`cloudflared recieved a warp-routing request with an empty host value: %w`, err) |
| 137 | c.log.Error().Err(err) |
| 138 | respWriter.WriteErrorResponse() |
| 139 | } |
| 140 | |
| 141 | rws := NewHTTPResponseReadWriterAcker(respWriter, r) |
| 142 | if err := c.config.OriginProxy.ProxyTCP(r.Context(), rws, &TCPRequest{ |
| 143 | Dest: host, |
| 144 | CFRay: FindCfRayHeader(r), |
| 145 | LBProbe: IsLBProbeRequest(r), |
| 146 | }); err != nil { |
| 147 | respWriter.WriteErrorResponse() |
| 148 | } |
| 149 | |
| 150 | default: |
| 151 | err := fmt.Errorf("Received unknown connection type: %s", connType) |
| 152 | c.log.Error().Err(err) |
| 153 | respWriter.WriteErrorResponse() |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | func (c *HTTP2Connection) serveControlStream(ctx context.Context, respWriter *http2RespWriter) error { |
| 158 | rpcClient := c.newRPCClientFunc(ctx, respWriter, c.observer.log) |
| 159 | defer rpcClient.Close() |
| 160 | |
| 161 | if err := rpcClient.RegisterConnection(ctx, c.namedTunnel, c.connOptions, c.connIndex, c.observer); err != nil { |
| 162 | return err |
| 163 | } |
| 164 | c.connectedFuse.Connected() |
| 165 | |
| 166 | // wait for connection termination or start of graceful shutdown |
| 167 | select { |
| 168 | case <-ctx.Done(): |
| 169 | break |
| 170 | case <-c.gracefulShutdownC: |
| 171 | c.stoppedGracefully = true |
| 172 | } |
| 173 | |
| 174 | c.observer.sendUnregisteringEvent(c.connIndex) |
| 175 | rpcClient.GracefulShutdown(ctx, c.config.GracePeriod) |
| 176 | c.observer.log.Info().Uint8(LogFieldConnIndex, c.connIndex).Msg("Unregistered tunnel connection") |
| 177 | return nil |
| 178 | } |
| 179 | |
| 180 | func (c *HTTP2Connection) close() { |
| 181 | // Wait for all serve HTTP handlers to return |
| 182 | c.activeRequestsWG.Wait() |
| 183 | c.conn.Close() |
| 184 | } |
| 185 | |
| 186 | type http2RespWriter struct { |
| 187 | r io.Reader |
| 188 | w http.ResponseWriter |
| 189 | flusher http.Flusher |
| 190 | shouldFlush bool |
| 191 | } |
| 192 | |
| 193 | func newHTTP2RespWriter(r *http.Request, w http.ResponseWriter, connType Type) (*http2RespWriter, error) { |
| 194 | flusher, isFlusher := w.(http.Flusher) |
| 195 | if !isFlusher { |
| 196 | respWriter := &http2RespWriter{ |
| 197 | r: r.Body, |
| 198 | w: w, |
| 199 | } |
| 200 | respWriter.WriteErrorResponse() |
| 201 | return nil, fmt.Errorf("%T doesn't implement http.Flusher", w) |
| 202 | } |
| 203 | |
| 204 | return &http2RespWriter{ |
| 205 | r: r.Body, |
| 206 | w: w, |
| 207 | flusher: flusher, |
| 208 | shouldFlush: connType.shouldFlush(), |
| 209 | }, nil |
| 210 | } |
| 211 | |
| 212 | func (rp *http2RespWriter) WriteRespHeaders(status int, header http.Header) error { |
| 213 | dest := rp.w.Header() |
| 214 | userHeaders := make(http.Header, len(header)) |
| 215 | for name, values := range header { |
| 216 | // Since these are http2 headers, they're required to be lowercase |
| 217 | h2name := strings.ToLower(name) |
| 218 | if h2name == "content-length" { |
| 219 | // This header has meaning in HTTP/2 and will be used by the edge, |
| 220 | // so it should be sent as an HTTP/2 response header. |
| 221 | dest[name] = values |
| 222 | // Since these are http2 headers, they're required to be lowercase |
| 223 | } else if !IsControlHeader(h2name) || IsWebsocketClientHeader(h2name) { |
| 224 | // User headers, on the other hand, must all be serialized so that |
| 225 | // HTTP/2 header validation won't be applied to HTTP/1 header values |
| 226 | userHeaders[name] = values |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | // Perform user header serialization and set them in the single header |
| 231 | dest.Set(CanonicalResponseUserHeaders, SerializeHeaders(userHeaders)) |
| 232 | rp.setResponseMetaHeader(responseMetaHeaderOrigin) |
| 233 | // HTTP2 removes support for 101 Switching Protocols https://tools.ietf.org/html/rfc7540#section-8.1.1 |
| 234 | if status == http.StatusSwitchingProtocols { |
| 235 | status = http.StatusOK |
| 236 | } |
| 237 | rp.w.WriteHeader(status) |
| 238 | if IsServerSentEvent(header) { |
| 239 | rp.shouldFlush = true |
| 240 | } |
| 241 | if rp.shouldFlush { |
| 242 | rp.flusher.Flush() |
| 243 | } |
| 244 | return nil |
| 245 | } |
| 246 | |
| 247 | func (rp *http2RespWriter) WriteErrorResponse() { |
| 248 | rp.setResponseMetaHeader(responseMetaHeaderCfd) |
| 249 | rp.w.WriteHeader(http.StatusBadGateway) |
| 250 | } |
| 251 | |
| 252 | func (rp *http2RespWriter) setResponseMetaHeader(value string) { |
| 253 | rp.w.Header().Set(CanonicalResponseMetaHeader, value) |
| 254 | } |
| 255 | |
| 256 | func (rp *http2RespWriter) Read(p []byte) (n int, err error) { |
| 257 | return rp.r.Read(p) |
| 258 | } |
| 259 | |
| 260 | func (rp *http2RespWriter) Write(p []byte) (n int, err error) { |
| 261 | defer func() { |
| 262 | // Implementer of OriginClient should make sure it doesn't write to the connection after Proxy returns |
| 263 | // Register a recover routine just in case. |
| 264 | if r := recover(); r != nil { |
| 265 | println("Recover from http2 response writer panic, error", r) |
| 266 | } |
| 267 | }() |
| 268 | n, err = rp.w.Write(p) |
| 269 | if err == nil && rp.shouldFlush { |
| 270 | rp.flusher.Flush() |
| 271 | } |
| 272 | return n, err |
| 273 | } |
| 274 | |
| 275 | func (rp *http2RespWriter) Close() error { |
| 276 | return nil |
| 277 | } |
| 278 | |
| 279 | func determineHTTP2Type(r *http.Request) Type { |
| 280 | switch { |
| 281 | case isWebsocketUpgrade(r): |
| 282 | return TypeWebsocket |
| 283 | case IsTCPStream(r): |
| 284 | return TypeTCP |
| 285 | case isControlStreamUpgrade(r): |
| 286 | return TypeControlStream |
| 287 | default: |
| 288 | return TypeHTTP |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | func handleMissingRequestParts(connType Type, r *http.Request) { |
| 293 | if connType == TypeHTTP { |
| 294 | // http library has no guarantees that we receive a filled URL. If not, then we fill it, as we reuse the request |
| 295 | // for proxying. We use the same values as we used to in h2mux. For proxying they should not matter since we |
| 296 | // control the dialer on every egress proxied. |
| 297 | if len(r.URL.Scheme) == 0 { |
| 298 | r.URL.Scheme = "http" |
| 299 | } |
| 300 | if len(r.URL.Host) == 0 { |
| 301 | r.URL.Host = "localhost:8080" |
| 302 | } |
| 303 | } |
| 304 | } |
| 305 | |
| 306 | func isControlStreamUpgrade(r *http.Request) bool { |
| 307 | return r.Header.Get(InternalUpgradeHeader) == ControlStreamUpgrade |
| 308 | } |
| 309 | |
| 310 | func isWebsocketUpgrade(r *http.Request) bool { |
| 311 | return r.Header.Get(InternalUpgradeHeader) == WebsocketUpgrade |
| 312 | } |
| 313 | |
| 314 | // IsTCPStream discerns if the connection request needs a tcp stream proxy. |
| 315 | func IsTCPStream(r *http.Request) bool { |
| 316 | return r.Header.Get(InternalTCPProxySrcHeader) != "" |
| 317 | } |
| 318 | |
| 319 | func stripWebsocketUpgradeHeader(r *http.Request) { |
| 320 | r.Header.Del(InternalUpgradeHeader) |
| 321 | } |
| 322 | |
| 323 | // getRequestHost returns the host of the http.Request. |
| 324 | func getRequestHost(r *http.Request) (string, error) { |
| 325 | if r.Host != "" { |
| 326 | return r.Host, nil |
| 327 | } |
| 328 | if r.URL != nil { |
| 329 | return r.URL.Host, nil |
| 330 | } |
| 331 | return "", errors.New("host not set in incoming request") |
| 332 | } |
| 333 | |