commit 74f37d9a32edee08cbbf3824dfc64eb9cfc6d7cc Author: David Fifield david@bamsoftware.com Date: Sun Nov 25 22:51:56 2012 -0800

Move WebSocket code to its own file. --- websocket-transport/Makefile | 2 +- websocket-transport/websocket-server.go | 132 +----------------------- websocket-transport/websocket.go | 172 +++++++++++++++++++++++++++++++ 3 files changed, 178 insertions(+), 128 deletions(-)

diff --git a/websocket-transport/Makefile b/websocket-transport/Makefile index 1fb2f76..013debd 100644 --- a/websocket-transport/Makefile +++ b/websocket-transport/Makefile @@ -3,7 +3,7 @@ PROGRAMS = websocket-client websocket-server all: $(PROGRAMS)

websocket-client: websocket-client.go socks.go pt.go -websocket-server: websocket-server.go pt.go +websocket-server: websocket-server.go pt.go websocket.go

%: %.go go build -o $@ $^ diff --git a/websocket-transport/websocket-server.go b/websocket-transport/websocket-server.go index c6effe4..a2f3652 100644 --- a/websocket-transport/websocket-server.go +++ b/websocket-transport/websocket-server.go @@ -1,15 +1,11 @@ package main

import ( - "bufio" - "crypto/sha1" - "encoding/base64" "fmt" "net" "net/http" "os" "os/signal" - "strings" )

const defaultPort = 9901 @@ -22,128 +18,8 @@ func logDebug(format string, v ...interface{}) { fmt.Fprintf(os.Stderr, format+"\n", v...) }

-func httpError(w http.ResponseWriter, bufrw *bufio.ReadWriter, code int) { - w.Header().Set("Connection", "close") - bufrw.WriteString(fmt.Sprintf("HTTP/1.0 %d %s\r\n", code, http.StatusText(code))) - w.Header().Write(bufrw) - bufrw.WriteString("\r\n") - bufrw.Flush() -} - -func commaSplit(s string) []string { - var result []string - if strings.TrimSpace(s) == "" { - return result - } - for _, e := range strings.Split(s, ",") { - result = append(result, strings.TrimSpace(e)) - } - return result -} - -func containsCase(haystack []string, needle string) bool { - for _, e := range haystack { - if strings.ToLower(e) == strings.ToLower(needle) { - return true - } - } - return false -} - -func sha1Hash(data string) []byte { - h := sha1.New() - h.Write([]byte(data)) - return h.Sum(nil) -} - -func handler(w http.ResponseWriter, req *http.Request) { - conn, bufrw, err := w.(http.Hijacker).Hijack() - if err != nil { - http.Error(w, err.Error(), http.StatusInternalServerError) - return - } - defer conn.Close() - - // See RFC 6455 section 4.2.1 for this sequence of checks. - - // 1. An HTTP/1.1 or higher GET request, including a "Request-URI"... - if req.Method != "GET" { - httpError(w, bufrw, http.StatusMethodNotAllowed) - return - } - if req.URL.Path != "/" { - httpError(w, bufrw, http.StatusNotFound) - return - } - // 2. A |Host| header field containing the server's authority. - // We deliberately skip this test. - // 3. An |Upgrade| header field containing the value "websocket", - // treated as an ASCII case-insensitive value. - if !containsCase(commaSplit(req.Header.Get("Upgrade")), "websocket") { - httpError(w, bufrw, http.StatusBadRequest) - return - } - // 4. A |Connection| header field that includes the token "Upgrade", - // treated as an ASCII case-insensitive value. - if !containsCase(commaSplit(req.Header.Get("Connection")), "Upgrade") { - httpError(w, bufrw, http.StatusBadRequest) - return - } - // 5. A |Sec-WebSocket-Key| header field with a base64-encoded value - // that, when decoded, is 16 bytes in length. - websocketKey := req.Header.Get("Sec-WebSocket-Key") - key, err := base64.StdEncoding.DecodeString(websocketKey) - if err != nil || len(key) != 16 { - httpError(w, bufrw, http.StatusBadRequest) - return - } - // 6. A |Sec-WebSocket-Version| header field, with a value of 13. - // We also allow 8 from draft-ietf-hybi-thewebsocketprotocol-10. - var knownVersions = []string{"8", "13"} - websocketVersion := req.Header.Get("Sec-WebSocket-Version") - if !containsCase(knownVersions, websocketVersion) { - // "If this version does not match a version understood by the - // server, the server MUST abort the WebSocket handshake - // described in this section and instead send an appropriate - // HTTP error code (such as 426 Upgrade Required) and a - // |Sec-WebSocket-Version| header field indicating the - // version(s) the server is capable of understanding." - w.Header().Set("Sec-WebSocket-Version", strings.Join(knownVersions, ", ")) - httpError(w, bufrw, 426) - return - } - // 7. Optionally, an |Origin| header field. - // 8. Optionally, a |Sec-WebSocket-Protocol| header field, with a list of - // values indicating which protocols the client would like to speak, ordered - // by preference. - _ = commaSplit(req.Header.Get("Sec-WebSocket-Protocol")) - // 9. Optionally, a |Sec-WebSocket-Extensions| header field... - // 10. Optionally, other header fields... - - // See RFC 6455 section 4.2.2, item 5 for these steps. - - // 1. A Status-Line with a 101 response code as per RFC 2616. - bufrw.WriteString(fmt.Sprintf("HTTP/1.0 %d %s\r\n", http.StatusSwitchingProtocols, http.StatusText(http.StatusSwitchingProtocols))) - // 2. An |Upgrade| header field with value "websocket" as per RFC 2616. - w.Header().Set("Upgrade", "websocket") - // 3. A |Connection| header field with value "Upgrade". - w.Header().Set("Connection", "Upgrade") - // 4. A |Sec-WebSocket-Accept| header field. The value of this header - // field is constructed by concatenating /key/, defined above in step 4 - // in Section 4.2.2, with the string - // "258EAFA5-E914-47DA-95CA-C5AB0DC85B11", taking the SHA-1 hash of this - // concatenated value to obtain a 20-byte value and base64-encoding (see - // Section 4 of [RFC4648]) this 20-byte hash. - const magicGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" - acceptKey := base64.StdEncoding.EncodeToString(sha1Hash(websocketKey + magicGUID)) - w.Header().Set("Sec-WebSocket-Accept", acceptKey) - // 5. Optionally, a |Sec-WebSocket-Protocol| header field, with a value - // /subprotocol/ as defined in step 4 in Section 4.2.2. - // w.Header().Set("Sec-WebSocket-Protocol", "base64") - // 6. Optionally, a |Sec-WebSocket-Extensions| header field... - w.Header().Write(bufrw) - bufrw.WriteString("\r\n") - bufrw.Flush() +func websocketHandler(ws *websocket) { + fmt.Printf("blah\n") }

func startListener(addr *net.TCPAddr) (*net.TCPListener, error) { @@ -152,7 +28,9 @@ func startListener(addr *net.TCPAddr) (*net.TCPListener, error) { return nil, err } go func() { - http.HandleFunc("/", handler) + var config websocketConfig + config.Subprotocols = []string{"base64"} + http.Handle("/", config.Handler(websocketHandler)) err = http.Serve(ln, nil) if err != nil { panic("http.Serve: " + err.Error()) diff --git a/websocket-transport/websocket.go b/websocket-transport/websocket.go new file mode 100644 index 0000000..9ac9754 --- /dev/null +++ b/websocket-transport/websocket.go @@ -0,0 +1,172 @@ +package main + +import ( + "bufio" + "crypto/sha1" + "encoding/base64" + "fmt" + "net" + "net/http" + "strings" +) + +type websocketConfig struct { + Subprotocols []string +} + +type websocket struct { + Conn net.Conn + Bufrw *bufio.ReadWriter + // Whether we are a client or a server implications for masking. + IsClient bool + Subprotocol string +} + +func commaSplit(s string) []string { + var result []string + if strings.TrimSpace(s) == "" { + return result + } + for _, e := range strings.Split(s, ",") { + result = append(result, strings.TrimSpace(e)) + } + return result +} + +func containsCase(haystack []string, needle string) bool { + for _, e := range haystack { + if strings.ToLower(e) == strings.ToLower(needle) { + return true + } + } + return false +} + +func sha1Hash(data string) []byte { + h := sha1.New() + h.Write([]byte(data)) + return h.Sum(nil) +} + +func httpError(w http.ResponseWriter, bufrw *bufio.ReadWriter, code int) { + w.Header().Set("Connection", "close") + bufrw.WriteString(fmt.Sprintf("HTTP/1.0 %d %s\r\n", code, http.StatusText(code))) + w.Header().Write(bufrw) + bufrw.WriteString("\r\n") + bufrw.Flush() +} + +type WebSocketHTTPHandler struct { + config *websocketConfig + websocketCallback func(*websocket) +} + +func (handler *WebSocketHTTPHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) { + conn, bufrw, err := w.(http.Hijacker).Hijack() + if err != nil { + http.Error(w, err.Error(), http.StatusInternalServerError) + return + } + defer conn.Close() + + // See RFC 6455 section 4.2.1 for this sequence of checks. + + // 1. An HTTP/1.1 or higher GET request, including a "Request-URI"... + if req.Method != "GET" { + httpError(w, bufrw, http.StatusMethodNotAllowed) + return + } + if req.URL.Path != "/" { + httpError(w, bufrw, http.StatusNotFound) + return + } + // 2. A |Host| header field containing the server's authority. + // We deliberately skip this test. + // 3. An |Upgrade| header field containing the value "websocket", + // treated as an ASCII case-insensitive value. + if !containsCase(commaSplit(req.Header.Get("Upgrade")), "websocket") { + httpError(w, bufrw, http.StatusBadRequest) + return + } + // 4. A |Connection| header field that includes the token "Upgrade", + // treated as an ASCII case-insensitive value. + if !containsCase(commaSplit(req.Header.Get("Connection")), "Upgrade") { + httpError(w, bufrw, http.StatusBadRequest) + return + } + // 5. A |Sec-WebSocket-Key| header field with a base64-encoded value + // that, when decoded, is 16 bytes in length. + websocketKey := req.Header.Get("Sec-WebSocket-Key") + key, err := base64.StdEncoding.DecodeString(websocketKey) + if err != nil || len(key) != 16 { + httpError(w, bufrw, http.StatusBadRequest) + return + } + // 6. A |Sec-WebSocket-Version| header field, with a value of 13. + // We also allow 8 from draft-ietf-hybi-thewebsocketprotocol-10. + var knownVersions = []string{"8", "13"} + websocketVersion := req.Header.Get("Sec-WebSocket-Version") + if !containsCase(knownVersions, websocketVersion) { + // "If this version does not match a version understood by the + // server, the server MUST abort the WebSocket handshake + // described in this section and instead send an appropriate + // HTTP error code (such as 426 Upgrade Required) and a + // |Sec-WebSocket-Version| header field indicating the + // version(s) the server is capable of understanding." + w.Header().Set("Sec-WebSocket-Version", strings.Join(knownVersions, ", ")) + httpError(w, bufrw, 426) + return + } + // 7. Optionally, an |Origin| header field. + // 8. Optionally, a |Sec-WebSocket-Protocol| header field, with a list of + // values indicating which protocols the client would like to speak, ordered + // by preference. + clientProtocols := commaSplit(req.Header.Get("Sec-WebSocket-Protocol")) + // 9. Optionally, a |Sec-WebSocket-Extensions| header field... + // 10. Optionally, other header fields... + + var ws websocket + ws.Conn = conn + ws.Bufrw = bufrw + ws.IsClient = false + + // See RFC 6455 section 4.2.2, item 5 for these steps. + + // 1. A Status-Line with a 101 response code as per RFC 2616. + bufrw.WriteString(fmt.Sprintf("HTTP/1.0 %d %s\r\n", http.StatusSwitchingProtocols, http.StatusText(http.StatusSwitchingProtocols))) + // 2. An |Upgrade| header field with value "websocket" as per RFC 2616. + w.Header().Set("Upgrade", "websocket") + // 3. A |Connection| header field with value "Upgrade". + w.Header().Set("Connection", "Upgrade") + // 4. A |Sec-WebSocket-Accept| header field. The value of this header + // field is constructed by concatenating /key/, defined above in step 4 + // in Section 4.2.2, with the string + // "258EAFA5-E914-47DA-95CA-C5AB0DC85B11", taking the SHA-1 hash of this + // concatenated value to obtain a 20-byte value and base64-encoding (see + // Section 4 of [RFC4648]) this 20-byte hash. + const magicGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" + acceptKey := base64.StdEncoding.EncodeToString(sha1Hash(websocketKey + magicGUID)) + w.Header().Set("Sec-WebSocket-Accept", acceptKey) + // 5. Optionally, a |Sec-WebSocket-Protocol| header field, with a value + // /subprotocol/ as defined in step 4 in Section 4.2.2. + for _, clientProto := range clientProtocols { + for _, serverProto := range handler.config.Subprotocols { + if clientProto == serverProto { + ws.Subprotocol = clientProto + w.Header().Set("Sec-WebSocket-Protocol", clientProto) + break + } + } + } + // 6. Optionally, a |Sec-WebSocket-Extensions| header field... + w.Header().Write(bufrw) + bufrw.WriteString("\r\n") + bufrw.Flush() + + // Call the WebSocket-specific handler. + handler.websocketCallback(&ws) +} + +func (config *websocketConfig) Handler(f func(*websocket)) http.Handler { + return &WebSocketHTTPHandler{config, f} +}