SRv6 endpoint encoding

Author: wnagele

main.go

@@ -2,11 +2,14 @@ package main
 
 import (
 	"context"
+	"encoding/binary"
 	"fmt"
 	"golang.org/x/sync/errgroup"
 	"log"
+	"net"
 	"os"
 	"os/signal"
+	"strconv"
 	"syscall"
 
 	"github.com/spf13/cobra"
@@ -19,6 +22,7 @@ import (
 var configFile string
 
 func initConfig() {
+	viper.SetDefault("srv6_net", "fc00::/56")
 	viper.SetDefault("socket_path", "/var/run/galactic/agent.sock")
 	viper.SetDefault("mqtt_host", "mqtt")
 	viper.SetDefault("mqtt_port", 1883)
@@ -52,16 +56,35 @@ func main() {
 			ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 			defer stop() //nolint:errcheck
 
+			_, err := EncodeVPCToSRv6Endpoint(viper.GetString("srv6_net"), "ffffffffffff", "ffff")
+			if err != nil {
+				log.Fatalf("srv6_endpoint invalid: %v", err)
+			}
+
 			l = local.Local{
 				SocketPath: viper.GetString("socket_path"),
 				RegisterHandler: func(vpc, vpcAttachment string, networks []string) error {
-					log.Printf("REGISTER:   vpc='%v', vpcattachment='%v', networks='%v'\n", vpc, vpcAttachment, networks)
-					r.Send(fmt.Sprintf("REGISTER:   vpc='%v', vpcattachment='%v', networks='%v'", vpc, vpcAttachment, networks))
+					srv6_endpoint, err := EncodeVPCToSRv6Endpoint(viper.GetString("srv6_net"), vpc, vpcAttachment)
+					if err != nil {
+						return err
+					}
+					for _, n := range networks {
+						payload := fmt.Sprintf("REGISTER: network='%s', srv6_endpoint='%s'", n, srv6_endpoint)
+						log.Println(payload)
+						r.Send(payload)
+					}
 					return nil
 				},
 				DeregisterHandler: func(vpc, vpcAttachment string, networks []string) error {
-					log.Printf("DEREGISTER: vpc='%v', vpcattachment='%v', networks='%v'\n", vpc, vpcAttachment, networks)
-					r.Send(fmt.Sprintf("DEREGISTER: vpc='%v', vpcattachment='%v', networks='%v'", vpc, vpcAttachment, networks))
+					srv6_endpoint, err := EncodeVPCToSRv6Endpoint(viper.GetString("srv6_net"), vpc, vpcAttachment)
+					if err != nil {
+						return err
+					}
+					for _, n := range networks {
+						payload := fmt.Sprintf("DEREGISTER: network='%s', srv6_endpoint='%s'", n, srv6_endpoint)
+						log.Println(payload)
+						r.Send(payload)
+					}
 					return nil
 				},
 			}
@@ -96,3 +119,29 @@ func main() {
 		log.Fatalf("Execution failed: %v", err)
 	}
 }
+
+func EncodeVPCToSRv6Endpoint(srv6_net, vpc, vpcAttachment string) (string, error) {
+	ip, ipnet, err := net.ParseCIDR(srv6_net)
+	if err != nil {
+		return "", err
+	}
+	if ip.To4() != nil {
+		return "", fmt.Errorf("provided srv6_net is not IPv6: %s", srv6_net)
+	}
+	mask_len, _ := ipnet.Mask.Size()
+	if mask_len > 64 {
+		return "", fmt.Errorf("srv6_net must be at least 64 bits long")
+	}
+
+	vpcInt, err := strconv.ParseUint(vpc, 16, 64)
+	if err != nil {
+		return "", fmt.Errorf("invalid vpc %q: %w", vpc, err)
+	}
+	vpcAttachmentInt, err := strconv.ParseUint(vpcAttachment, 16, 16)
+	if err != nil {
+		return "", fmt.Errorf("invalid vpcAttachment %q: %w", vpcAttachment, err)
+	}
+
+	binary.BigEndian.PutUint64(ip[8:16], (vpcInt<<16)|vpcAttachmentInt)
+	return ip.String(), nil
+}