added ipv4 and udp checksum calclulation, fixed sime arpspoof related functions

Author: shadowy-pycoder

README.md

@@ -31,7 +31,6 @@ sudo setcap cap_net_raw+ep ~/go/bin/mshark
 
 ```shell
 mshark -h
-
                 ______   __                            __
                /      \ |  \                          |  \
  ______ ____  |  $$$$$$\| $$____    ______    ______  | $$   __
@@ -49,22 +48,23 @@ GitHub: https://github.com/shadowy-pycoder/mshark
 Usage: mshark [OPTIONS]
 Options:
   -h    Show this help message and exit.
-  -D    Display list of interfaces and exit.
+  -D	Display list of interfaces and exit.
+  -V	Show version and build information
   -b int
-        The maximum size of packet queue. (default 8192)
+    	The maximum size of packet queue. (default 8192)
   -c int
-        The maximum number of packets to capture.
+    	The maximum number of packets to capture.
   -e string
-        BPF filter expression. Example: "ip proto tcp"
+    	BPF filter expression. Example: "ip proto tcp".
   -f value
-        File extension(s) to write captured data. Supported formats: stdout, txt, pcap, pcapng
+    	File extension(s) to write captured data. Supported formats: stdout, txt, pcap, pcapng
   -i string
-        The name of the network interface. Example: eth0 (default "any")
-  -p    Promiscuous mode. This setting is ignored for "any" interface. Defaults to false.
+    	The name of the network interface. Example: eth0 (default "any")
+  -p	Promiscuous mode. This setting is ignored for "any" interface. Defaults to false.
   -s int
-        The maximum length of each packet snapshot. Defaults to 65535.
+    	The maximum length of each packet snapshot. Defaults to 65535.
   -t duration
-        The maximum duration of the packet capture process. Example: 5s
+    	The maximum duration of the packet capture process. Example: 5s
   -v	Display full packet info when capturing to stdout or txt.
 ```
 

arpspoof/arpspoof.go

@@ -87,7 +87,7 @@ func (at *ARPTable) Delete(ip netip.Addr) {
 func (at *ARPTable) Refresh() error {
 	at.Lock()
 	defer at.Unlock()
-	cmd := exec.Command("sh", "-c", "ip -br neigh")
+	cmd := exec.Command("sh", "-c", "ip -4 -br neigh")
 	out, err := cmd.Output()
 	if err != nil {
 		return err
@@ -175,7 +175,7 @@ func NewARPSpoofer(conf *ARPSpoofConfig) (*ARPSpoofer, error) {
 		arpspoofer.gwIP = gwIP
 	}
 	if gwMAC, ok := arpspoofer.arpTable.Get(arpspoofer.gwIP); !ok {
-		probeIP(arpspoofer.gwIP)
+		doPing(arpspoofer.gwIP)
 		time.Sleep(probeThrottling)
 		err = arpspoofer.arpTable.Refresh()
 		if err != nil {
@@ -294,8 +294,7 @@ func (ar *ARPSpoofer) Stop() error {
 	return err
 }
 
-func doProbe(ip netip.Addr) error {
-	// TODO: add manual packet crafting
+func doPing(ip netip.Addr) error {
 	ping := exec.Command("sh", "-c", fmt.Sprintf("ping -c1 -t1 -w1 %s", ip))
 	if err := ping.Start(); err != nil {
 		return err
@@ -306,8 +305,14 @@ func doProbe(ip netip.Addr) error {
 	return nil
 }
 
-func probeIP(ip netip.Addr) error {
-	return doProbe(ip)
+func (ar *ARPSpoofer) doProbe(ip netip.Addr) error {
+	// TODO: add parsing ARP replies
+	ap, err := ar.newARPRequest(ar.hostMAC, ar.hostIP, ip)
+	if err != nil {
+		return err
+	}
+	ar.packets <- ap
+	return nil
 }
 
 func (ar *ARPSpoofer) probeTargetsOnce() {
@@ -316,7 +321,7 @@ func (ar *ARPSpoofer) probeTargetsOnce() {
 		wg.Add(1)
 		go func(ip netip.Addr) {
 			defer wg.Done()
-			doProbe(ip)
+			doPing(ip)
 		}(ip)
 		time.Sleep(probeThrottling)
 	}
@@ -338,7 +343,7 @@ func (ar *ARPSpoofer) probeTargets() {
 				wg.Add(1)
 				go func(ip netip.Addr) {
 					defer wg.Done()
-					doProbe(ip)
+					doPing(ip)
 				}(ip)
 				time.Sleep(probeThrottling)
 			}
@@ -390,6 +395,20 @@ func (ar *ARPSpoofer) newARPReply(srcMAC, dstMAC net.HardwareAddr, srcIP, dstIP
 	return &Packet{addr: dstMAC, data: eth.ToBytes()}, nil
 }
 
+func (ar *ARPSpoofer) newARPRequest(srcMAC net.HardwareAddr, srcIP, dstIP netip.Addr) (*Packet, error) {
+	arp, err := layers.NewARPPacket(layers.OperationRequest, srcMAC, srcIP, network.LoopbackMAC, dstIP)
+	if err != nil {
+		ar.logger.Debug().Msg(err.Error())
+		return nil, err
+	}
+	eth, err := layers.NewEthernetFrame(network.BroadcastMAC, srcMAC, layers.EtherTypeARP, arp.ToBytes())
+	if err != nil {
+		ar.logger.Debug().Msg(err.Error())
+		return nil, err
+	}
+	return &Packet{addr: network.BroadcastMAC, data: eth.ToBytes()}, nil
+}
+
 func (ar *ARPSpoofer) spoofTargets() {
 	for _, targetIP := range ar.targets {
 		if targetMAC, ok := ar.arpTable.Get(targetIP); !ok {

cmd/mshark/cli.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"runtime"
 	"slices"
 	"strings"
 	"time"
@@ -17,8 +18,7 @@ import (
 
 const app string = "mshark"
 
-const usagePrefix string = `
-                ______   __                            __
+const usagePrefix string = `                ______   __                            __
                /      \ |  \                          |  \
  ______ ____  |  $$$$$$\| $$____    ______    ______  | $$   __
 |      \    \ | $$___\$$| $$    \  |      \  /      \ | $$  /  \
@@ -108,6 +108,11 @@ func root(args []string) error {
 		fmt.Print(usagePrefix)
 		flags.PrintDefaults()
 	}
+	flags.BoolFunc("V", "Show version and build information", func(flagValue string) error {
+		fmt.Printf("%s (built for %s %s with %s)\n", ms.Version, runtime.GOOS, runtime.GOARCH, runtime.Version())
+		os.Exit(0)
+		return nil
+	})
 
 	if err := flags.Parse(args); err != nil {
 		return err