vendor update github.com/gorilla/websocket

vendor/golang.org/x/net/ipv4/header.go

@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"net"
 	"runtime"
-	"syscall"
 
 	"golang.org/x/net/internal/socket"
 )
@@ -52,9 +51,13 @@ func (h *Header) String() string {
 }
 
 // Marshal returns the binary encoding of h.
+//
+// The returned slice is in the format used by a raw IP socket on the
+// local system.
+// This may differ from the wire format, depending on the system.
 func (h *Header) Marshal() ([]byte, error) {
 	if h == nil {
-		return nil, syscall.EINVAL
+		return nil, errNilHeader
 	}
 	if h.Len < HeaderLen {
 		return nil, errHeaderTooShort
@@ -99,13 +102,20 @@ func (h *Header) Marshal() ([]byte, error) {
 }
 
 // Parse parses b as an IPv4 header and stores the result in h.
+//
+// The provided b must be in the format used by a raw IP socket on the
+// local system.
+// This may differ from the wire format, depending on the system.
 func (h *Header) Parse(b []byte) error {
-	if h == nil || len(b) < HeaderLen {
+	if h == nil || b == nil {
+		return errNilHeader
+	}
+	if len(b) < HeaderLen {
 		return errHeaderTooShort
 	}
 	hdrlen := int(b[0]&0x0f) << 2
-	if hdrlen > len(b) {
-		return errBufferTooShort
+	if len(b) < hdrlen {
+		return errExtHeaderTooShort
 	}
 	h.Version = int(b[0] >> 4)
 	h.Len = hdrlen
@@ -150,6 +160,10 @@ func (h *Header) Parse(b []byte) error {
 }
 
 // ParseHeader parses b as an IPv4 header.
+//
+// The provided b must be in the format used by a raw IP socket on the
+// local system.
+// This may differ from the wire format, depending on the system.
 func ParseHeader(b []byte) (*Header, error) {
 	h := new(Header)
 	if err := h.Parse(b); err != nil {