config.go

package main

import (
	"encoding/binary"
	"fmt"
	"net"
)

// Config is the configurations for the bpf program.
type Config struct {
	CatchCount uint64
	IP         string
	ip         uint32
	Proto      string
	proto      uint8
	IcmpID     uint16
	Port       uint16
	Pid        uint32
	NetNS      uint32
	DropStack  bool
	CallStack  bool
	Iptables   bool
	NoRoute    bool
	Time       bool
	Timestamp  bool
	Gops       string
}

var cfg Config

func init() {

	fs := rootCmd.PersistentFlags()
	fs.StringVarP(&cfg.IP, "ipaddr", "H", "", "ip address")
	fs.StringVar(&cfg.Proto, "proto", "", "tcp|udp|icmp|any")
	fs.Uint16Var(&cfg.IcmpID, "icmpid", 0, "trace icmp id")
	fs.Uint64VarP(&cfg.CatchCount, "catch-count", "c", 1000, "catch and print count")
	fs.Uint16VarP(&cfg.Port, "port", "P", 0, "udp or tcp port")
	fs.Uint32VarP(&cfg.Pid, "pid", "p", 0, "trace this PID only")
	fs.Uint32VarP(&cfg.NetNS, "netns", "N", 0, "trace this netns inode only")
	fs.BoolVar(&cfg.DropStack, "dropstack", false, "output kernel stack trace when drop packet")
	fs.BoolVar(&cfg.CallStack, "callstack", false, "output kernel stack trace")
	fs.BoolVar(&cfg.Iptables, "iptables", false, "output iptables path")
	fs.BoolVar(&cfg.NoRoute, "noroute", false, "do not output route path")
	fs.BoolVarP(&cfg.Time, "time", "T", true, "show HH:MM:SS timestamp")
	fs.BoolVarP(&cfg.Timestamp, "timestamp", "t", false, "show timestamp in seconds at us resolution")
	fs.StringVar(&cfg.Gops, "gops", "", "gops address")
}

func (c *Config) parse() error {

	ip := c.IP
	if ip != "" {
		ip := net.ParseIP(ip)
		ip = ip.To4()
		if ip == nil {
			return fmt.Errorf("invalid IPv4 addr(%s)", ip)
		}

		c.ip = binary.BigEndian.Uint32(ip)
	}

	proto := c.Proto
	if proto != "" {
		switch proto {
		case "tcp":
			c.proto = 6
		case "udp":
			c.proto = 17
		case "icmp":
			c.proto = 1
		case "any":
		default:
			return fmt.Errorf("invalid proto(%s)", proto)
		}
	}

	return nil
}