initial import from gitlab... more clean up required.

Author: dmabry

.gitignore

@@ -1,21 +1,25 @@
-# If you prefer the allow list template instead of the deny list, see community template:
-# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
-#
 # Binaries for programs and plugins
 *.exe
 *.exe~
 *.dll
 *.so
 *.dylib
+*.tgz
 
 # Test binary, built with `go test -c`
 *.test
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
+# Leave out idea
+.idea/
+
 # Dependency directories (remove the comment below to include it)
-# vendor/
+vendor/
+# Ignore default recorded_flows dir
+recorded_flows/
+# Ignore all prod
+prod_*
 
-# Go workspace file
-go.work
+dist/

Dockerfile

@@ -0,0 +1,26 @@
+# ---- Base ----
+FROM docker.ena.net/alpine/base AS build-stage
+LABEL application=flowproxy-build
+
+COPY . /opt/go/src/gitlab.ena.net/netflow/flowproxy
+WORKDIR /opt/go/src/gitlab.ena.net/netflow/flowproxy
+
+RUN apk add --update make libpcap-dev
+
+# build
+RUN make build
+
+# deploy
+FROM docker.ena.net/alpine/deploy AS deploy
+LABEL application=flowproxy
+
+# add some alpine deps
+RUN apk add --update --no-cache tzdata
+
+ENV CONSUL_HTTP_ADDR http://cnl01.dev.ena.net:8500
+
+WORKDIR /opt/flowproxy/
+# copy executable
+COPY --from=build-stage /opt/go/src/gitlab.ena.net/netflow/flowproxy/flowproxy ./
+# copy docroot
+# COPY --from=build-stage /opt/go/src/gitlab.ena.net/netflow/flowproxy/docroot      ./docroot

common/common.go

@@ -0,0 +1,111 @@
+package common
+
+import (
+	"bytes"
+	crand "crypto/rand"
+	"encoding/binary"
+	"fmt"
+	"github.com/mostlygeek/arp"
+	"log"
+	"math/big"
+	"net"
+	"os/exec"
+	"runtime"
+	"strings"
+)
+
+func CryptoRandomNumber(max int64) int64 {
+	n, err := crand.Int(crand.Reader, big.NewInt(max))
+	if err != nil {
+		panic(fmt.Errorf("crypto number failed to read bytes %v", err))
+	}
+	return n.Int64()
+}
+
+// RandomNum Generates a random number between the given min and max
+func RandomNum(min, max int) int {
+	return int(CryptoRandomNumber(int64(max-min))) + min
+}
+
+func BinaryReader(reader *bytes.Reader, dests ...interface{}) error {
+	for _, dest := range dests {
+		err := binary.Read(reader, binary.BigEndian, dest)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func LookupMACAddr(ipAddr net.IP) (macAddr net.HardwareAddr, e error) {
+	// check if ipAddr is local
+	// find all devices
+	devices, err := net.Interfaces()
+	if err != nil {
+		return nil, err
+	}
+
+	for _, device := range devices {
+		//DEBUG
+		//fmt.Printf("device: %s mac: %s\n", device.Name, device.HardwareAddr)
+		addresses, _ := device.Addrs()
+		for _, address := range addresses {
+			//DEBUG
+			//fmt.Printf("\taddress: %s\n", address)
+			deviceIPAddr, _, _ := net.ParseCIDR(address.String())
+			if deviceIPAddr != nil {
+				if ipAddr.Equal(deviceIPAddr) {
+					// found IP locally, grab the interface and return it
+					return device.HardwareAddr, nil
+				}
+			} else {
+				deviceIPAddr = net.ParseIP(address.String())
+				if ipAddr.Equal(deviceIPAddr) {
+					return device.HardwareAddr, nil
+				}
+			}
+		}
+	}
+	// give ipAddr was not found locally, so lets move on to ARP
+	// ping first to force the OS to resolve mac address
+	cmd := exec.Command("ping", "-c", "1", ipAddr.String())
+	err = cmd.Run()
+	if err != nil {
+		log.Printf("Failed to ping %s: %s", ipAddr, err)
+		return nil, err
+	}
+	mac := arp.Search(ipAddr.String())
+	if runtime.GOOS == "darwin" {
+		mac = DarwinMACFormat(mac)
+	}
+	macParsed, err := net.ParseMAC(mac)
+	if err != nil {
+		fmt.Printf("Error parsing destination MAC: %s - %s\n", mac, err)
+		return nil, err
+	}
+	return macParsed, nil
+}
+
+// DarwinMACFormat fixes the issue that macOS returns oddly formatted arp -a results
+func DarwinMACFormat(macString string) string {
+	var group int
+	var builder strings.Builder
+	for i := 0; i < len(macString); i++ {
+		r := macString[i]
+		if r == ':' {
+			for chars := group; chars < 2; chars++ {
+				builder.WriteString("0")
+			}
+			builder.WriteString(macString[i-group : i])
+			builder.WriteString(":")
+			group = 0
+			continue
+		}
+		group++
+	}
+	for chars := group; chars < 2; chars++ {
+		builder.WriteString("0")
+	}
+	builder.WriteString(macString[len(macString)-group:])
+	return builder.String()
+}