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kdhcp
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checkpoint

This commit is contained in:
Kyle Isom 2023-05-01 14:37:52 +00:00
parent 25642eff64
commit 9eb32a3174
9 changed files with 193 additions and 82 deletions
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5
cmd/kdhcpd/BUILD.bazel
View File

@ -5,7 +5,10 @@ go_library(
srcs = ["main.go"],
importpath = "git.wntrmute.dev/kyle/kdhcp/cmd/kdhcpd",
visibility = ["//visibility:private"],
deps = ["//server"],
deps = [
"//log",
"//server",
],
)
go_binary(

23
cmd/kdhcpd/main.go
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@ -2,18 +2,33 @@ package main
import (
"flag"
"log"
"git.wntrmute.dev/kyle/kdhcp/log"
"git.wntrmute.dev/kyle/kdhcp/server"
)
func main() {
cfg := &server.Config{}
flag.StringVar(&cfg.Device, "i", "eth0", "network `interface` to listen on")
cfg := server.DefaultConfig()
var level, tag string
flag.StringVar(&level, "l", "DEBUG", "log level") // TODO(kyle): change this warning later
flag.IntVar(&cfg.Port, "p", cfg.Port, "port to listen on")
flag.StringVar(&tag, "t", "kdhcpd", "logging tag")
flag.Parse()
_, err := server.NewServer(cfg)
log.Setup(level, tag)
srv, err := server.NewServer(cfg)
if err != nil {
log.Fatal(err)
}
for {
packet, err := srv.ReadFrom()
if err != nil {
log.Warning(err)
continue
}
log.Debugf("receive %d byte packet from %s", len(packet.Data), packet.Addr)
}
}

2
log/BUILD.bazel
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@ -5,5 +5,5 @@ go_library(
srcs = ["logger.go"],
importpath = "git.wntrmute.dev/kyle/kdhcp/log",
visibility = ["//visibility:public"],
deps = ["@com_github_hashicorp_go_syslog//:go-syslog"],
deps = ["//bazel-kdhcp/external/com_github_hashicorp_go_syslog:go-syslog"],
)

49
log/logger.go
View File

@ -2,6 +2,8 @@ package log
import (
"fmt"
"os"
"strings"
"time"
gsyslog "github.com/hashicorp/go-syslog"
@ -13,6 +15,10 @@ type logger struct {
}
func (log *logger) printf(p gsyslog.Priority, format string, args ...interface{}) {
if !strings.HasSuffix(format, "\n") {
format += "\n"
}
if p <= log.p {
fmt.Printf("%s [%s] ", prioritiev[p], timestamp())
fmt.Printf(format, args...)
@ -158,34 +164,45 @@ func Emergln(args ...interface{}) {
log.println(gsyslog.LOG_EMERG, args...)
}
func Debugf(args ...interface{}) {
log.printf(gsyslog.LOG_DEBUG, args...)
func Debugf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_DEBUG, format, args...)
}
func Infof(args ...interface{}) {
log.printf(gsyslog.LOG_INFO, args...)
func Infof(format string, args ...interface{}) {
log.printf(gsyslog.LOG_INFO, format, args...)
}
func Noticef(args ...interface{}) {
log.printf(gsyslog.LOG_NOTICE, args...)
func Noticef(format string, args ...interface{}) {
log.printf(gsyslog.LOG_NOTICE, format, args...)
}
func Warningf(args ...interface{}) {
log.print(gsyslog.LOG_WARNING, args...)
func Warningf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_WARNING, format, args...)
}
func Errf(args ...interface{}) {
log.printf(gsyslog.LOG_ERR, args...)
func Errf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_ERR, format, args...)
}
func Critf(args ...interface{}) {
log.printf(gsyslog.LOG_CRIT, args...)
func Critf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_CRIT, format, args...)
}
func Alertf(args ...interface{}) {
log.printf(gsyslog.LOG_ALERT, args...)
func Alertf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_ALERT, format, args...)
}
func Emergf(args ...interface{}) {
log.printf(gsyslog.LOG_EMERG, args...)
func Emergf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_EMERG, format, args...)
os.Exit(1)
}
func Fatal(args ...interface{}) {
log.println(gsyslog.LOG_ERR, args...)
os.Exit(1)
}
func Fatalf(format string, args ...interface{}) {
log.printf(gsyslog.LOG_ERR, format, args...)
os.Exit(1)
}

12
server/BUILD.bazel
View File

@ -2,8 +2,16 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library")
go_library(
name = "server",
srcs = ["server.go"],
srcs = [
"addr.go",
"config.go",
"packet.go",
"server.go",
],
importpath = "git.wntrmute.dev/kyle/kdhcp/server",
visibility = ["//visibility:public"],
deps = ["@com_github_davecgh_go_spew//spew"],
deps = [
"//bazel-kdhcp/external/com_github_davecgh_go_spew/spew",
"//log",
],
)

61
server/addr.go Normal file
View File

@ -0,0 +1,61 @@
package server
import (
"fmt"
"net"
"git.wntrmute.dev/kyle/kdhcp/bazel-kdhcp/external/com_github_davecgh_go_spew/spew"
"git.wntrmute.dev/kyle/kdhcp/log"
)
type addr struct {
ifi *net.Interface
IP net.IP
ipn *net.IPNet
}
func addrsForDevice(dev string) ([]addr, error) {
netInterface, err := net.InterfaceByName(dev)
if err != nil {
return nil, fmt.Errorf("while selecting interface %s: %w", dev, err)
}
spew.Dump(netInterface)
var addrs []addr
devAddrs, err := netInterface.Addrs()
if err != nil {
return nil, err
}
for _, devAddr := range devAddrs {
log.Debugf("consider %s", devAddr.String())
ip, ipn, err := net.ParseCIDR(devAddr.String())
if err != nil {
continue
}
if ip == nil {
continue // address isn't an IP address
}
log.Debugf("found IP: %s", ip)
ip = ip.To4()
// DHCP should only listen on private addresses.
if !ip.IsPrivate() {
log.Debugln("skipping non-private")
continue
}
// only support IPv4 for now
if len(ip) != 4 {
log.Debugf("%d IP, only supporting v4 right now", len(ip))
continue
}
addrs = append(addrs, addr{netInterface, ip, ipn})
}
return addrs, nil
}

19
server/config.go Normal file
View File

@ -0,0 +1,19 @@
package server
const (
DefaultPort = 67
DefaultMaxPacketSize = 512
DefaultNetwork = "udp4"
)
type Config struct {
Port int
MaxPacketSize int
}
func DefaultConfig() *Config {
return &Config{
Port: DefaultPort,
MaxPacketSize: DefaultMaxPacketSize,
}
}

8
server/packet.go Normal file
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@ -0,0 +1,8 @@
package server
import "net"
type Packet struct {
Data []byte
Addr net.Addr
}

96
server/server.go
View File

@ -1,82 +1,62 @@
package server
import (
"errors"
"log"
"fmt"
"net"
"github.com/davecgh/go-spew/spew"
"git.wntrmute.dev/kyle/kdhcp/log"
)
// github.com/insomniacslk/dhcp
type addr struct {
IP net.IP
ipn *net.IPNet
}
type Config struct {
Device string `yaml:"device"`
}
type Server struct {
addrs []net.IP
l net.Listener
cfg *Config
conn net.PacketConn
}
func addrsForDevice(dev string) ([]addr, error) {
netInterface, err := net.InterfaceByName(dev)
func (srv *Server) Listen() (err error) {
if srv.conn != nil {
srv.conn.Close()
}
log.Debugf("attempting to set up packet listener on %s 0.0.0.0:%d", DefaultNetwork, srv.cfg.Port)
srv.conn, err = net.ListenPacket(DefaultNetwork, fmt.Sprintf(":%d", srv.cfg.Port))
if err != nil {
return err
}
return nil
}
func (srv *Server) Close() error {
if srv.conn != nil {
return srv.conn.Close()
}
return nil
}
func (srv *Server) ReadFrom() (*Packet, error) {
b := make([]byte, srv.cfg.MaxPacketSize)
n, addr, err := srv.conn.ReadFrom(b)
if err != nil {
return nil, err
}
spew.Dump(netInterface)
var addrs []addr
devAddrs, err := netInterface.Addrs()
if err != nil {
return nil, err
}
for _, devAddr := range devAddrs {
log.Printf("consider %s", devAddr.String())
ip, ipn, err := net.ParseCIDR(devAddr.String())
if err != nil {
continue
}
if ip == nil {
continue // address isn't an IP address
}
log.Printf("found IP: %s", ip)
ip = ip.To4()
// DHCP should only listen on private addresses.
if !ip.IsPrivate() {
log.Println("skipping non-private")
continue
}
// only support IPv4 for now
if len(ip) != 4 {
log.Printf("%d IP, only supporting v4 right now", len(ip))
continue
}
addrs = append(addrs, addr{ip, ipn})
}
return addrs, nil
return &Packet{
Data: b[:n],
Addr: addr,
}, nil
}
func NewServer(cfg *Config) (*Server, error) {
addrs, err := addrsForDevice(cfg.Device)
srv := &Server{
cfg: cfg,
}
err := srv.Listen()
if err != nil {
return nil, err
}
log.Println("server IP list: ", addrs)
return nil, errors.New("not implemented")
return srv, nil
}