WriteFileHeader writes a file header out to the writer. This must be called exactly once per output.
(snaplen uint32, linktype layers.LinkType)
| 78 | // WriteFileHeader writes a file header out to the writer. |
| 79 | // This must be called exactly once per output. |
| 80 | func (w *Writer) WriteFileHeader(snaplen uint32, linktype layers.LinkType) error { |
| 81 | var buf [24]byte |
| 82 | if w.tsScaler == nanosPerMicro { |
| 83 | binary.LittleEndian.PutUint32(buf[0:4], magicMicroseconds) |
| 84 | } else { |
| 85 | binary.LittleEndian.PutUint32(buf[0:4], magicNanoseconds) |
| 86 | } |
| 87 | binary.LittleEndian.PutUint16(buf[4:6], versionMajor) |
| 88 | binary.LittleEndian.PutUint16(buf[6:8], versionMinor) |
| 89 | // bytes 8:12 stay 0 (timezone = UTC) |
| 90 | // bytes 12:16 stay 0 (sigfigs is always set to zero, according to |
| 91 | // http://wiki.wireshark.org/Development/LibpcapFileFormat |
| 92 | binary.LittleEndian.PutUint32(buf[16:20], snaplen) |
| 93 | binary.LittleEndian.PutUint32(buf[20:24], uint32(linktype)) |
| 94 | _, err := w.w.Write(buf[:]) |
| 95 | return err |
| 96 | } |
| 97 | |
| 98 | const nanosPerMicro = 1000 |
| 99 | const nanosPerNano = 1 |