1 files changed, 103 insertions, 0 deletions
diff --git a/vendor/github.com/google/gopacket/pcapgo/write.go b/vendor/github.com/google/gopacket/pcapgo/write.go
new file mode 100644
index 0000000..bfc312f
--- /dev/null
+++ b/vendor/github.com/google/gopacket/pcapgo/write.go
@@ -0,0 +1,103 @@
+// Copyright 2012 Google, Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+// Package pcapgo provides some native PCAP support, not requiring
+// C libpcap to be installed.
+package pcapgo
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"time"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+)
+
+// Writer wraps an underlying io.Writer to write packet data in PCAP
+// format.  See http://wiki.wireshark.org/Development/LibpcapFileFormat
+// for information on the file format.
+//
+// For those that care, we currently write v2.4 files with nanosecond
+// timestamp resolution and little-endian encoding.
+type Writer struct {
+	w io.Writer
+}
+
+const magicMicroseconds = 0xA1B2C3D4
+const versionMajor = 2
+const versionMinor = 4
+
+// NewWriter returns a new writer object, for writing packet data out
+// to the given writer.  If this is a new empty writer (as opposed to
+// an append), you must call WriteFileHeader before WritePacket.
+//
+//  // Write a new file:
+//  f, _ := os.Create("/tmp/file.pcap")
+//  w := pcapgo.NewWriter(f)
+//  w.WriteFileHeader(65536, layers.LinkTypeEthernet)  // new file, must do this.
+//  w.WritePacket(gopacket.CaptureInfo{...}, data1)
+//  f.Close()
+//  // Append to existing file (must have same snaplen and linktype)
+//  f2, _ := os.OpenFile("/tmp/file.pcap", os.O_APPEND, 0700)
+//  w2 := pcapgo.NewWriter(f2)
+//  // no need for file header, it's already written.
+//  w2.WritePacket(gopacket.CaptureInfo{...}, data2)
+//  f2.Close()
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{w: w}
+}
+
+// WriteFileHeader writes a file header out to the writer.
+// This must be called exactly once per output.
+func (w *Writer) WriteFileHeader(snaplen uint32, linktype layers.LinkType) error {
+	var buf [24]byte
+	binary.LittleEndian.PutUint32(buf[0:4], magicMicroseconds)
+	binary.LittleEndian.PutUint16(buf[4:6], versionMajor)
+	binary.LittleEndian.PutUint16(buf[6:8], versionMinor)
+	// bytes 8:12 stay 0 (timezone = UTC)
+	// bytes 12:16 stay 0 (sigfigs is always set to zero, according to
+	//   http://wiki.wireshark.org/Development/LibpcapFileFormat
+	binary.LittleEndian.PutUint32(buf[16:20], snaplen)
+	binary.LittleEndian.PutUint32(buf[20:24], uint32(linktype))
+	_, err := w.w.Write(buf[:])
+	return err
+}
+
+const nanosPerMicro = 1000
+
+func (w *Writer) writePacketHeader(ci gopacket.CaptureInfo) error {
+	var buf [16]byte
+
+	t := ci.Timestamp
+	if t.IsZero() {
+		t = time.Now()
+	}
+	secs := t.Unix()
+	usecs := t.Nanosecond() / nanosPerMicro
+	binary.LittleEndian.PutUint32(buf[0:4], uint32(secs))
+	binary.LittleEndian.PutUint32(buf[4:8], uint32(usecs))
+	binary.LittleEndian.PutUint32(buf[8:12], uint32(ci.CaptureLength))
+	binary.LittleEndian.PutUint32(buf[12:16], uint32(ci.Length))
+	_, err := w.w.Write(buf[:])
+	return err
+}
+
+// WritePacket writes the given packet data out to the file.
+func (w *Writer) WritePacket(ci gopacket.CaptureInfo, data []byte) error {
+	if ci.CaptureLength != len(data) {
+		return fmt.Errorf("capture length %d does not match data length %d", ci.CaptureLength, len(data))
+	}
+	if ci.CaptureLength > ci.Length {
+		return fmt.Errorf("invalid capture info %+v:  capture length > length", ci)
+	}
+	if err := w.writePacketHeader(ci); err != nil {
+		return fmt.Errorf("error writing packet header: %v", err)
+	}
+	_, err := w.w.Write(data)
+	return err
+}