added main source file

connet.service

@@ -0,0 +1,25 @@
+
+[Unit]
+Description=MACVLAN setup
+#Documentation=man:systemd-networkd.service(8)
+ConditionCapability=CAP_NET_ADMIN
+DefaultDependencies=no
+# dbus.service can be dropped once on kdbus, and systemd-udevd.service can be
+# dropped once tuntap is moved to netlink
+After=systemd-udevd.service dbus.service network-pre.target systemd-sysusers.service systemd-sysctl.service
+Before=network.target multi-user.target shutdown.target
+Conflicts=shutdown.target
+Wants=network.target
+
+
+[Service]
+# the VT is cleared by TTYVTDisallocate
+RemainAfterExit=yes
+#Environment=IP_ADDR= GATEWAY_ADDR=
+EnvironmentFile=/proc/1/environ
+ExecStart=/connet
+Type=oneshot
+[Install]
+WantedBy=multi-user.target
+
+

main.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+    "github.com/vishvananda/netlink"
+    "io/ioutil"
+    "strings"
+    "net"
+    "fmt"
+    "os"
+    "regexp"
+)
+
+var env map[string]string=make(map[string]string)
+
+func main(){
+   readInitEnviron()
+
+   macAddr,_ := net.ParseMAC(getEnv("IF_ADDR"))
+//   fpAddr,_ := netlink.ParseAddr(getEnv("IP_ADDR"))
+//   gatewayAddr := net.ParseIP(getEnv("GATEWAY_ADDR"))
+
+   linkInterfaceType:=getEnvWithDefault("IF_TYPE","macvlan")
+
+   link:=findFirstInterface(linkInterfaceType)
+
+   renameInterface(link,"eth0")
+
+   renameMacAddress(link,macAddr)
+
+/*
+   #netlink.AddrAdd(link,ipAddr)
+
+   #netlink.LinkSetUp(link)
+
+   #addRoute(gatewayAddr,link)
+*/
+}
+
+func readInitEnviron(){
+    envFilePath:="/proc/1/environ"
+    content, err := ioutil.ReadFile(envFilePath)
+    kvParseRegex,_:=regexp.Compile("^([^=]+)=(.+)$")
+    if err != nil {
+        panic(fmt.Sprintf("environ file  %s not existed!",envFilePath))
+    }
+    lines := strings.Split(string(content), "\x00")
+    for _,element := range lines {
+        result_slice := kvParseRegex.FindStringSubmatch(element)
+        if len(result_slice) < 2 {
+            continue
+        }else{
+            env[result_slice[1]]=result_slice[2]
+        }
+    }
+}
+func renameMacAddress(link netlink.Link,new_name net.HardwareAddr){
+  err:=netlink.LinkSetHardwareAddr(link,new_name)
+  if(err != nil){
+        panic(fmt.Sprintf("cannot rename mac address %s -> %s",link.Attrs().HardwareAddr,new_name))
+   } else {
+        fmt.Printf("rename mac address %s -> %s\n",link.Attrs().HardwareAddr,new_name)
+   }
+
+}
+
+func renameInterface(link netlink.Link,new_name string) {
+   err:=netlink.LinkSetName(link,new_name)
+   if(err != nil){
+        panic(fmt.Sprintf("cannot rename interface %s -> %s",link.Attrs().Name,new_name))
+   } else {
+        fmt.Printf("rename interface %s -> %s\n",link.Attrs().Name,new_name)
+   }
+}
+
+func findFirstInterface(if_type string) netlink.Link {
+   links,_:=netlink.LinkList()
+   for _,element := range links {
+       if(element.Type() == if_type){
+           fmt.Println(element.Attrs().Name)
+           return element
+       }
+   }
+   panic(fmt.Sprintf("cannot get type: %s interface",if_type))
+}
+
+func getEnv(variable string) string {
+   envValue,ok:=env[variable]
+   if ok {
+       return envValue
+   }
+   envValue=os.Getenv(variable)
+
+   if(envValue == ""){
+       panic(fmt.Sprintf("cannot get ${%s}",variable))
+   } else{
+       return envValue
+   }
+}
+
+func getEnvWithDefault(variable string, ret_is_empty string) string {
+   envValue,ok:=env[variable]
+   if ok {
+       return envValue
+   }
+   envValue=os.Getenv(variable)
+
+   if(envValue == ""){
+       return ret_is_empty
+   } else{
+       return envValue
+   }
+}
+
+func addRoute(gateway net.IP,link netlink.Link){
+	default_network := &net.IPNet{
+		IP:   net.IPv4(0, 0, 0, 0),
+		Mask: net.CIDRMask(0, 32),
+	}
+
+	route := &netlink.Route{LinkIndex: link.Attrs().Index, Dst: default_network, Gw:gateway}
+
+	netlink.RouteAdd(route)
+}