calculate version negotiation packet size to avoid bytes.Buffer growing the bytes

This commit is contained in:
mawei 2020-05-13 12:34:39 +08:00
parent 6bcb4e69ee
commit 38691a1278

View file

@ -11,7 +11,7 @@ import (
// ComposeVersionNegotiation composes a Version Negotiation
func ComposeVersionNegotiation(destConnID, srcConnID protocol.ConnectionID, versions []protocol.VersionNumber) ([]byte, error) {
greasedVersions := protocol.GetGreasedVersions(versions)
expectedLen := 1 /* type byte */ + 4 /* version field */ + 1 /* connection ID length field */ + destConnID.Len() + srcConnID.Len() + len(greasedVersions)*4
expectedLen := 1 /* type byte */ + 4 /* version field */ + 1 /* dest connection ID length field */ + destConnID.Len() + 1 /* src connection ID length field */ + srcConnID.Len() + len(greasedVersions)*4
buf := bytes.NewBuffer(make([]byte, 0, expectedLen))
r := make([]byte, 1)
_, _ = rand.Read(r) // ignore the error here. It is not critical to have perfect random here.