From d235e2c6a5788ec4a6cff15a16f56b38a3876a0d Mon Sep 17 00:00:00 2001 From: Determinant Date: Sun, 28 Jun 2020 14:47:41 -0400 Subject: ... --- rpc/websocket.go | 175 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 175 insertions(+) create mode 100644 rpc/websocket.go (limited to 'rpc/websocket.go') diff --git a/rpc/websocket.go b/rpc/websocket.go new file mode 100644 index 0000000..d87e8a5 --- /dev/null +++ b/rpc/websocket.go @@ -0,0 +1,175 @@ +// Copyright 2015 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see . + +package rpc + +import ( + "context" + "encoding/base64" + "fmt" + "net/http" + "net/url" + "os" + "strings" + "sync" + + mapset "github.com/deckarep/golang-set" + "github.com/ava-labs/go-ethereum/log" + "github.com/gorilla/websocket" +) + +const ( + wsReadBuffer = 1024 + wsWriteBuffer = 1024 +) + +var wsBufferPool = new(sync.Pool) + +// NewWSServer creates a new websocket RPC server around an API provider. +// +// Deprecated: use Server.WebsocketHandler +func NewWSServer(allowedOrigins []string, srv *Server) *http.Server { + return &http.Server{Handler: srv.WebsocketHandler(allowedOrigins)} +} + +// WebsocketHandler returns a handler that serves JSON-RPC to WebSocket connections. +// +// allowedOrigins should be a comma-separated list of allowed origin URLs. +// To allow connections with any origin, pass "*". +func (s *Server) WebsocketHandler(allowedOrigins []string) http.Handler { + var upgrader = websocket.Upgrader{ + ReadBufferSize: wsReadBuffer, + WriteBufferSize: wsWriteBuffer, + WriteBufferPool: wsBufferPool, + CheckOrigin: wsHandshakeValidator(allowedOrigins), + } + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + conn, err := upgrader.Upgrade(w, r, nil) + if err != nil { + log.Debug("WebSocket upgrade failed", "err", err) + return + } + codec := newWebsocketCodec(conn) + s.ServeCodec(codec, OptionMethodInvocation|OptionSubscriptions) + }) +} + +// wsHandshakeValidator returns a handler that verifies the origin during the +// websocket upgrade process. When a '*' is specified as an allowed origins all +// connections are accepted. +func wsHandshakeValidator(allowedOrigins []string) func(*http.Request) bool { + origins := mapset.NewSet() + allowAllOrigins := false + + for _, origin := range allowedOrigins { + if origin == "*" { + allowAllOrigins = true + } + if origin != "" { + origins.Add(strings.ToLower(origin)) + } + } + // allow localhost if no allowedOrigins are specified. + if len(origins.ToSlice()) == 0 { + origins.Add("http://localhost") + if hostname, err := os.Hostname(); err == nil { + origins.Add("http://" + strings.ToLower(hostname)) + } + } + log.Debug(fmt.Sprintf("Allowed origin(s) for WS RPC interface %v", origins.ToSlice())) + + f := func(req *http.Request) bool { + // Skip origin verification if no Origin header is present. The origin check + // is supposed to protect against browser based attacks. Browsers always set + // Origin. Non-browser software can put anything in origin and checking it doesn't + // provide additional security. + if _, ok := req.Header["Origin"]; !ok { + return true + } + // Verify origin against whitelist. + origin := strings.ToLower(req.Header.Get("Origin")) + if allowAllOrigins || origins.Contains(origin) { + return true + } + log.Warn("Rejected WebSocket connection", "origin", origin) + return false + } + + return f +} + +type wsHandshakeError struct { + err error + status string +} + +func (e wsHandshakeError) Error() string { + s := e.err.Error() + if e.status != "" { + s += " (HTTP status " + e.status + ")" + } + return s +} + +// DialWebsocket creates a new RPC client that communicates with a JSON-RPC server +// that is listening on the given endpoint. +// +// The context is used for the initial connection establishment. It does not +// affect subsequent interactions with the client. +func DialWebsocket(ctx context.Context, endpoint, origin string) (*Client, error) { + endpoint, header, err := wsClientHeaders(endpoint, origin) + if err != nil { + return nil, err + } + dialer := websocket.Dialer{ + ReadBufferSize: wsReadBuffer, + WriteBufferSize: wsWriteBuffer, + WriteBufferPool: wsBufferPool, + } + return newClient(ctx, func(ctx context.Context) (ServerCodec, error) { + conn, resp, err := dialer.DialContext(ctx, endpoint, header) + if err != nil { + hErr := wsHandshakeError{err: err} + if resp != nil { + hErr.status = resp.Status + } + return nil, hErr + } + return newWebsocketCodec(conn), nil + }) +} + +func wsClientHeaders(endpoint, origin string) (string, http.Header, error) { + endpointURL, err := url.Parse(endpoint) + if err != nil { + return endpoint, nil, err + } + header := make(http.Header) + if origin != "" { + header.Add("origin", origin) + } + if endpointURL.User != nil { + b64auth := base64.StdEncoding.EncodeToString([]byte(endpointURL.User.String())) + header.Add("authorization", "Basic "+b64auth) + endpointURL.User = nil + } + return endpointURL.String(), header, nil +} + +func newWebsocketCodec(conn *websocket.Conn) ServerCodec { + conn.SetReadLimit(maxRequestContentLength) + return newCodec(conn, conn.WriteJSON, conn.ReadJSON) +} -- cgit v1.2.3-70-g09d2