rpc: make max_body_bytes and max_header_bytes configurable (#3818)

* rpc: make max_body_bytes and max_header_bytes configurable

* update changelog pending

rpc/lib/server/handlers.go

@@ -448,6 +448,9 @@ type wsConnection struct {
 	// Send pings to server with this period. Must be less than readWait, but greater than zero.
 	pingPeriod time.Duration
 
+	// Maximum message size.
+	readLimit int64
+
 	// callback which is called upon disconnect
 	onDisconnect func(remoteAddr string)
 
@@ -467,7 +470,6 @@ func NewWSConnection(
 	cdc *amino.Codec,
 	options ...func(*wsConnection),
 ) *wsConnection {
-	baseConn.SetReadLimit(maxBodyBytes)
 	wsc := &wsConnection{
 		remoteAddr:        baseConn.RemoteAddr().String(),
 		baseConn:          baseConn,
@@ -481,6 +483,7 @@ func NewWSConnection(
 	for _, option := range options {
 		option(wsc)
 	}
+	wsc.baseConn.SetReadLimit(wsc.readLimit)
 	wsc.BaseService = *cmn.NewBaseService(nil, "wsConnection", wsc)
 	return wsc
 }
@@ -525,6 +528,14 @@ func PingPeriod(pingPeriod time.Duration) func(*wsConnection) {
 	}
 }
 
+// ReadLimit sets the maximum size for reading message.
+// It should only be used in the constructor - not Goroutine-safe.
+func ReadLimit(readLimit int64) func(*wsConnection) {
+	return func(wsc *wsConnection) {
+		wsc.readLimit = readLimit
+	}
+}
+
 // OnStart implements cmn.Service by starting the read and write routines. It
 // blocks until the connection closes.
 func (wsc *wsConnection) OnStart() error {