Don't hardcode source prefix in behaviors with ctrl

Author: louisroyer

internal/netfunc/headend-ctrl.go

@@ -24,14 +24,22 @@ func NewHeadendWithCtrl(he *config.Headend, ttl uint8, hopLimit uint8, setup_reg
 		if !ok {
 			return nil, fmt.Errorf("No database in the registry")
 		}
-		return NewNetFunc(NewHeadendEncapsWithCtrl(p, ttl, hopLimit, db)), nil
+		srcAddressPrefix, err := netip.ParsePrefix(*he.SourceAddressPrefix)
+		if err != nil {
+			return nil, err
+		}
+		return NewNetFunc(NewHeadendEncapsWithCtrl(p, srcAddressPrefix, ttl, hopLimit, db)), nil
 	case config.H_M_GTP4_D:
 		db, ok := setup_registry.DB()
 		if !ok {
 			return nil, fmt.Errorf("No database in the registry")
 		}
+		srcAddressPrefix, err := netip.ParsePrefix(*he.SourceAddressPrefix)
+		if err != nil {
+			return nil, err
+		}
 
-		g, err := NewHeadendGTP4WithCtrl(p, ttl, hopLimit, db)
+		g, err := NewHeadendGTP4WithCtrl(p, srcAddressPrefix, ttl, hopLimit, db)
 		if err != nil {
 			return nil, err
 		}

internal/netfunc/headend-encaps-ctrl.go

@@ -6,24 +6,29 @@ package netfunc
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"net/netip"
 
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
+
 	gopacket_srv6 "github.com/nextmn/gopacket-srv6"
+	"github.com/nextmn/rfc9433/encoding"
 	db_api "github.com/nextmn/srv6/internal/database/api"
 )
 
 type HeadendEncapsWithCtrl struct {
 	BaseHandler
-	db db_api.Downlink
+	db        db_api.Downlink
+	srcPrefix netip.Prefix
 }
 
-func NewHeadendEncapsWithCtrl(prefix netip.Prefix, ttl uint8, hopLimit uint8, db db_api.Downlink) *HeadendEncapsWithCtrl {
+func NewHeadendEncapsWithCtrl(prefix netip.Prefix, srcPrefix netip.Prefix, ttl uint8, hopLimit uint8, db db_api.Downlink) *HeadendEncapsWithCtrl {
 	return &HeadendEncapsWithCtrl{
 		BaseHandler: NewBaseHandler(prefix, ttl, hopLimit),
 		db:          db,
+		srcPrefix:   srcPrefix,
 	}
 }
 
@@ -40,7 +45,13 @@ func (h HeadendEncapsWithCtrl) Handle(ctx context.Context, packet []byte) ([]byt
 	if err != nil {
 		return nil, err
 	}
-	src := net.ParseIP("fc00:3:1:0A03:0001:0868::30") // FIXME: dont hardcode
+	srgw_gtp_ip := netip.MustParseAddr("10.3.0.1")                            // FIXME: dont hardcode
+	ipv6Src := encoding.NewMGTP4IPv6Src(h.srcPrefix, srgw_gtp_ip.As4(), 2152) // FIXME:dont hardcode udp port number to 2152
+	src, err := ipv6Src.Marshal()
+	if err != nil {
+		return nil, fmt.Errorf("Error during serialization of IPv6 SA: %w", err)
+	}
+
 	nextHop := action.NextHop.AsSlice()
 	ipheader := &layers.IPv6{
 		SrcIP: src,

internal/netfunc/headend-gtp4-ctrl.go

@@ -16,19 +16,20 @@ import (
 
 	gopacket_srv6 "github.com/nextmn/gopacket-srv6"
 	"github.com/nextmn/rfc9433/encoding"
-
 	db_api "github.com/nextmn/srv6/internal/database/api"
 )
 
 type HeadendGTP4WithCtrl struct {
 	BaseHandler
-	db db_api.Uplink
+	db        db_api.Uplink
+	srcPrefix netip.Prefix
 }
 
-func NewHeadendGTP4WithCtrl(prefix netip.Prefix, ttl uint8, hopLimit uint8, db db_api.Uplink) (*HeadendGTP4WithCtrl, error) {
+func NewHeadendGTP4WithCtrl(prefix netip.Prefix, srcPrefix netip.Prefix, ttl uint8, hopLimit uint8, db db_api.Uplink) (*HeadendGTP4WithCtrl, error) {
 	return &HeadendGTP4WithCtrl{
 		BaseHandler: NewBaseHandler(prefix, ttl, hopLimit),
 		db:          db,
+		srcPrefix:   srcPrefix,
 	}, nil
 }
 
@@ -83,12 +84,11 @@ func (h HeadendGTP4WithCtrl) Handle(ctx context.Context, packet []byte) ([]byte,
 	ipv4SA := pqt.NetworkLayer().NetworkFlow().Src().Raw()
 	udpSP := pqt.TransportLayer().TransportFlow().Src().Raw()
 
-	srcPrefix := netip.MustParsePrefix("fc00:1:1::/48") // FIXME: dont hardcode
-	ipv6SA := encoding.NewMGTP4IPv6Src(srcPrefix, [4]byte(ipv4SA), binary.BigEndian.Uint16(udpSP))
+	ipv6SA := encoding.NewMGTP4IPv6Src(h.srcPrefix, [4]byte(ipv4SA), binary.BigEndian.Uint16(udpSP))
 
 	src, err := ipv6SA.Marshal()
 	if err != nil {
-		return nil, fmt.Errorf("Error during serialization of IPv6 SA: %s", err)
+		return nil, fmt.Errorf("Error during serialization of IPv6 SA: %w", err)
 	}
 	nextHop := action.NextHop.AsSlice()