streaming

commit e3efd43f94e6f502942e52c0a77474c1ab474962
parent 97693535acd9ae096cffa7e635491aa97264c4a1
Author: Joshua Callary <joshuacallary@miraitechnologies.com.au>
Date:   Fri,  2 Aug 2024 02:47:13 +1000

pcap: Added Encoding function to encode to .pcap

Diffstat:
M
pcap/parser.go
 | 
27
+++++++++++++++++++++++----
M
pcap/parser_test.go
 | 
45
+++++++++++++++++++++++++++++++++++++++++++++
A
pcap/testing/pcap_file_encode.pcap
 | 
0

3 files changed, 68 insertions(+), 4 deletions(-)
diff --git a/pcap/parser.go b/pcap/parser.go
@@ -1,8 +1,10 @@
 package pcap
 
 import (
+	"bytes"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 )
 
@@ -35,9 +37,8 @@ type File struct {
 
 func decode(reader io.Reader) (*File, error) {
 	var header GlobalHeader
-	err := binary.Read(reader, binary.LittleEndian, &header)
 
-	if err != nil {
+	if err := binary.Read(reader, binary.LittleEndian, &header); err != nil {
 		return nil, err
 	}
 
@@ -58,8 +59,7 @@ func decode(reader io.Reader) (*File, error) {
 		}
 
 		data := make([]byte, header.InclLen)
-		_, err = io.ReadFull(reader, data)
-		if err != nil {
+		if _, err = io.ReadFull(reader, data); err != nil {
 			return nil, err
 		}
 
@@ -74,3 +74,22 @@ func decode(reader io.Reader) (*File, error) {
 		Packets: packets,
 	}, nil
 }
+
+func encode(file *File) ([]byte, error) {
+	buf := new(bytes.Buffer)
+
+	if err := binary.Write(buf, binary.LittleEndian, &file.Header); err != nil {
+		return nil, fmt.Errorf("global header: %v", err)
+	}
+
+	for _, packet := range file.Packets {
+		if err := binary.Write(buf, binary.LittleEndian, &packet.Header); err != nil {
+			return nil, fmt.Errorf("Packet Header: %v", err)
+		}
+		if err := binary.Write(buf, binary.LittleEndian, &packet.Data); err != nil {
+			return nil, fmt.Errorf("Packet Data: %v", err)
+		}
+	}
+
+	return buf.Bytes(), nil
+}
diff --git a/pcap/parser_test.go b/pcap/parser_test.go
@@ -31,4 +31,49 @@ func TestReadFile(t *testing.T) {
 
 		fmt.Printf("Data %d: %x\n", i, packet.Data)
 	}
+
+	encodePcapFile, err := encode(pcapFile)
+
+	if err != nil {
+		t.Fatalf("encode file: %v", err)
+	}
+
+	fmt.Printf("Encoded PCAP: %x\n", encodePcapFile)
+
+	f, err := os.Create("testing/pcap_file_encode.pcap")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	_, err = f.Write(encodePcapFile)
+	if err != nil {
+		t.Fatalf("Failed to write to PCAP file")
+	}
+
+	filePathTwo := "testing/pcap_file_encode.pcap"
+
+	fileTwo, err := os.Open(filePathTwo)
+	if err != nil {
+		t.Fatal("Failed to open file")
+	}
+	defer fileTwo.Close()
+
+	pcap, err := decode(fileTwo)
+	if err != nil {
+		t.Fatalf("Failed to read PCAP file: %v", err)
+	}
+
+	if len(pcap.Packets) == 0 {
+		t.Fatal("Should be at least one packet but there is 0")
+	}
+
+	fmt.Printf("PCAP Header: %+v\n", pcap.Header)
+
+	for i, packet := range pcap.Packets {
+		fmt.Printf("Packet %d: %+v\n", i, packet.Header)
+
+		fmt.Printf("Data %d: %x\n", i, packet.Data)
+	}
+
 }
diff --git a/pcap/testing/pcap_file_encode.pcap b/pcap/testing/pcap_file_encode.pcap
Binary files differ.