f-51: netif: poser l'adresse VTEP locale des VXLAN #51

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/netif/vxlan.go

@@ -1,14 +1,31 @@
 package netif
 
 import (
+	"fmt"
+	"net"
+	"syscall"
+
 	"github.com/vishvananda/netlink"
 )
 
+const (
+	scopeUniverse    = 0
+	addressSecondary = 0x01
+)
+
 func CreateVxlan(name string, vxlanID int, localIface string, mtu int) error {
 	link, err := netlink.LinkByName(localIface)
 	if err != nil {
 		return err
 	}
+	addrs, err := netlink.AddrList(link, syscall.AF_INET)
+	if err != nil {
+		return err
+	}
+	local, err := vtepAddress(localIface, addrs)
+	if err != nil {
+		return err
+	}
 	vxlan := &netlink.Vxlan{
 		LinkAttrs: netlink.LinkAttrs{
 			Name: name,
@@ -17,7 +34,18 @@ func CreateVxlan(name string, vxlanID int, localIface string, mtu int) error {
 		VxlanId:      vxlanID,
 		Port:         4789,
 		VtepDevIndex: link.Attrs().Index,
+		SrcAddr:      local,
 		Learning:     false,
 	}
 	return netlink.LinkAdd(vxlan)
 }
+
+func vtepAddress(iface string, addrs []netlink.Addr) (net.IP, error) {
+	for _, a := range addrs {
+		if a.IPNet == nil || a.IP.To4() == nil || a.Scope != scopeUniverse || a.Flags&addressSecondary != 0 {
+			continue
+		}
+		return a.IP.To4(), nil
+	}
+	return nil, fmt.Errorf("no primary global IPv4 address on %s for the VXLAN local endpoint", iface)
+}