add ipv6 support

README.md

@@ -5,7 +5,10 @@
 [![Go Doc](https://godoc.org/github.com/exaring/pmtud?status.svg)](https://godoc.org/github.com/exaring/pmtud)
 
 In ECMP or L4 load balanced environments ICMP messages are mostly routed to the wrong servers.
-Path MTU Discovery Daemon solves this problem by "broadcasting" received ICMP packet too big messages to all backend instances of an L3/L4 load balanced service using IPIP encapsulation.
+Path MTU Discovery Daemon solves this problem by "broadcasting" received ICMP packet too big messages to all backend
+instances of an L3/L4 load balanced service using IPIP ([RFC2003](https://datatracker.ietf.org/doc/html/rfc2003))
+(legacy IP) and IPv6 Encapsulation ([RFC2473](https://datatracker.ietf.org/doc/html/rfc2473#section-3) (IPv6).
+
 Some Details:
 
   * https://tools.ietf.org/html/draft-jaeggli-v6ops-pmtud-ecmp-problem-00
@@ -31,4 +34,6 @@ interfaces: ["enp4s0"]
 backends:
   - 10.0.0.0
   - 10.0.0.1
+  - 2001:db8::1
+  - 2001:db8::2
 ```

config.yaml

@@ -2,3 +2,5 @@ interfaces: ["enp4s0"]
 backends:
   - 192.0.2.0
   - 192.0.2.1
+  - 2001:db8::1
+  - 2001:db8::2

go.mod

@@ -1,14 +1,24 @@
 module github.com/exaring/pmtud
 
-go 1.15
+go 1.23
 
 require (
 	github.com/google/gopacket v1.1.19
-	github.com/pkg/errors v0.9.1
-	github.com/prometheus/client_golang v1.9.0
-	github.com/q3k/goveralls v0.1.0
-	github.com/sirupsen/logrus v1.8.1
-	go.uber.org/zap v1.16.0
-	golang.org/x/net v0.0.0-20210316092652-d523dce5a7f4
+	github.com/prometheus/client_golang v1.20.3
+	go.uber.org/zap v1.27.0
+	golang.org/x/net v0.29.0
 	gopkg.in/yaml.v2 v2.4.0
 )
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/klauspost/compress v1.17.9 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/prometheus/client_model v0.6.1 // indirect
+	github.com/prometheus/common v0.59.1 // indirect
+	github.com/prometheus/procfs v0.15.1 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/sys v0.25.0 // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
+)

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"flag"
+	"log"
 	"net/http"
 
 	"github.com/exaring/pmtud/pkg/config"
@@ -10,8 +11,6 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-
-	log "github.com/sirupsen/logrus"
 )
 
 var (
@@ -23,24 +22,28 @@ func main() {
 
 	cfg, err := config.GetConfig(*cfgFilePath)
 	if err != nil {
-		log.WithError(err).Fatal("Unable to get config")
+		log.Fatalf("unable to get config: %s", err)
 	}
 
 	relays := make([]*icmp34relay.Relay, 0)
 	for _, ifa := range cfg.Interfaces {
 		relay, err := icmp34relay.New(ifa, cfg.GetBackends())
 		if err != nil {
-			log.WithError(err).Fatal("Unable to get ICMP34 relay")
+			log.Fatalf("unable to get ICMP34 relay: %s", err)
 		}
 
 		err = relay.Start()
 		if err != nil {
-			log.WithError(err).Fatal("Unable to start relay")
+			log.Fatalf("unable to start relay: %s", err)
 		}
 
 		relays = append(relays, relay)
 	}
 
+	if len(relays) == 0 {
+		log.Fatal("no matching interface found")
+	}
+
 	m := metrics.New(relays)
 	prometheus.Register(m)
 

pkg/config/config.go

@@ -1,42 +1,42 @@
 package config
 
 import (
-	"io/ioutil"
-	"net"
+	"fmt"
+	"net/netip"
+	"os"
 
-	"github.com/pkg/errors"
 	"gopkg.in/yaml.v2"
 )
 
 // Config represents a config file
 type Config struct {
 	Interfaces []string `yaml:"interfaces"`
 	Backends   []string `yaml:"backends"`
-	backends   []net.IP
+	backends   []netip.Addr
 }
 
 // GetConfig gets the config
 func GetConfig(fp string) (*Config, error) {
-	fc, err := ioutil.ReadFile(fp)
+	fc, err := os.ReadFile(fp)
 	if err != nil {
-		return nil, errors.Wrap(err, "Unable to read file")
+		return nil, fmt.Errorf("Unable to read file: %w", err)
 	}
 
 	cfg := &Config{
 		Interfaces: make([]string, 0),
 		Backends:   make([]string, 0),
-		backends:   make([]net.IP, 0),
+		backends:   make([]netip.Addr, 0),
 	}
 
 	err = yaml.Unmarshal(fc, cfg)
 	if err != nil {
-		return nil, errors.Wrap(err, "Unable to unmarshal YAML file")
+		return nil, fmt.Errorf("Unable to unmarshal YAML file: %w", err)
 	}
 
 	for _, b := range cfg.Backends {
-		a := net.ParseIP(b)
-		if a == nil {
-			return nil, errors.Wrapf(err, "Unable to parse IP: %s", b)
+		a, err := netip.ParseAddr(b)
+		if err != nil {
+			return nil, fmt.Errorf("Unable to parse IP '%s': %w", b, err)
 		}
 
 		cfg.backends = append(cfg.backends, a)
@@ -46,6 +46,6 @@ func GetConfig(fp string) (*Config, error) {
 }
 
 // GetBackends gets the backends
-func (c *Config) GetBackends() []net.IP {
+func (c *Config) GetBackends() []netip.Addr {
 	return c.backends
 }