package netlink import ( "fmt" "net" "strings" "syscall" "unsafe" ) type IfAddrmsg struct { syscall.IfAddrmsg } func newIfAddrmsg(family int) *IfAddrmsg { return &IfAddrmsg{ IfAddrmsg: syscall.IfAddrmsg{ Family: uint8(family), }, } } // struct ifaddrmsg { // __u8 ifa_family; // __u8 ifa_prefixlen; /* The prefix length */ // __u8 ifa_flags; /* Flags */ // __u8 ifa_scope; /* Address scope */ // __u32 ifa_index; /* Link index */ // }; // type IfAddrmsg struct { // Family uint8 // Prefixlen uint8 // Flags uint8 // Scope uint8 // Index uint32 // } // SizeofIfAddrmsg = 0x8 func DeserializeIfAddrmsg(b []byte) *IfAddrmsg { return (*IfAddrmsg)(unsafe.Pointer(&b[0:syscall.SizeofIfAddrmsg][0])) } func (msg *IfAddrmsg) Serialize() []byte { return (*(*[syscall.SizeofIfAddrmsg]byte)(unsafe.Pointer(msg)))[:] } func (msg *IfAddrmsg) Len() int { return syscall.SizeofIfAddrmsg } // AddrAdd will add an IP address to a link device. // Equivalent to: `ip addr del $addr dev $link` func AddrAdd(link *Link, addr *Addr) error { req := newNetlinkRequest(syscall.RTM_NEWADDR, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK) return addrHandle(link, addr, req) } // AddrDel will delete an IP address from a link device. // Equivalent to: `ip addr del $addr dev $link` func AddrDel(link *Link, addr *Addr) error { req := newNetlinkRequest(syscall.RTM_DELADDR, syscall.NLM_F_ACK) return addrHandle(link, addr, req) } func addrHandle(link *Link, addr *Addr, req *NetlinkRequest) error { if addr.Label != "" && !strings.HasPrefix(addr.Label, link.Name) { return fmt.Errorf("label must begin with interface name") } ensureIndex(link) family := GetIPFamily(addr.IP) msg := newIfAddrmsg(family) msg.Index = uint32(link.Index) prefixlen, _ := addr.Mask.Size() msg.Prefixlen = uint8(prefixlen) req.AddData(msg) var addrData []byte if family == FAMILY_V4 { addrData = addr.IP.To4() } else { addrData = addr.IP.To16() } localData := newRtAttr(syscall.IFA_LOCAL, addrData) req.AddData(localData) addressData := newRtAttr(syscall.IFA_ADDRESS, addrData) req.AddData(addressData) if addr.Label != "" { labelData := newRtAttr(syscall.IFA_LABEL, zeroTerminated(addr.Label)) req.AddData(labelData) } _, err := req.Execute(syscall.NETLINK_ROUTE, 0) return err } // AddrList gets a list of IP addresses in the system. // Equivalent to: `ip addr show`. // The list can be filtered by link and ip family. func AddrList(link *Link, family int) ([]Addr, error) { req := newNetlinkRequest(syscall.RTM_GETADDR, syscall.NLM_F_DUMP) msg := newIfInfomsg(family) req.AddData(msg) msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWADDR) if err != nil { return nil, err } ensureIndex(link) res := make([]Addr, 0) for _, m := range msgs { msg := DeserializeIfAddrmsg(m) if link != nil && msg.Index != uint32(link.Index) { // Ignore messages from other interfaces continue } attrs, err := parseRouteAttr(m[msg.Len():]) if err != nil { return nil, err } var addr Addr for _, attr := range attrs { switch attr.Attr.Type { case syscall.IFA_ADDRESS: addr.IPNet = net.IPNet{ IP: attr.Value, Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)), } case syscall.IFA_LABEL: addr.Label = string(attr.Value[:len(attr.Value)-1]) } } res = append(res, addr) } return res, nil }