SoFunction
Updated on 2025-03-05

How to implement golang to grab tcp package

Implementation of golang crawling tcp package

To crawl a TCP requested packet, you can use the `packet` library and the `pcap` library in `golang`.

Here is a way to use these libraries to crawl TCP packets:

first:

Make sure the `pcap` library is installed

You can use the following command to install:

go get -u /google/gopacket

Next:

You can use the following code to grab the TCP packet

package main

import (
    "fmt"
    "log"
    "os"
    "time"

    "/google/gopacket"
    "/google/gopacket/pcap"
)

func main() {
    // Get the interface name, for example "eth0" or "en0"    device := [1]

    // Turn on the device    handle, err := (device, 1600, true, )
    if err != nil {
        (err)
    }
    defer ()

    // Set filtering rules to only crawl TCP packets    err = ("tcp")
    if err != nil {
        (err)
    }

    // Start capturing packets    packetSource := (handle, ())
    for packet := range () {
        // Get TCP packets        tcpLayer := ()
        if tcpLayer != nil {
            tcpPacket := tcpLayer.(*)

            // Print source address, source port, destination address, destination port            ("Source Address: %s:%d\n", ().NetworkFlow().Src().String(), )
            ("Destination address: %s:%d\n", ().NetworkFlow().Dst().String(), )
            
            // Print TCP data content            ("TCP Data:", string())
        }
    }

    // Stop catching the packet after capturing for a period of time    (10 * )
    ()
}

This sample code opens the specified network interface, sets the filtering rule to "tcp", and then starts capturing TCP packets.

For each captured packet, it checks whether it is a TCP packet and prints the contents of the source address, source port, destination address, destination port, and TCP data.

You can use the following command to run the code

and specify the network interface to crawl (for example "eth0" or "en0"):

```shell
go run tcp_packet_capture.go <Interface name>
```

Please note:

Executing this program requires administrator privileges or run as root.

Summarize

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