package netlink // Network namespace ID functions // // The kernel has a weird concept called the network namespace ID. // This is different from the file reference in proc (and any bind-mounted // namespaces, etc.) // // Instead, namespaces can be assigned a numeric ID at any time. Once set, // the ID is fixed. The ID can either be set manually by the user, or // automatically, triggered by certain kernel actions. The most common kernel // action that triggers namespace ID creation is moving one end of a veth pair // in to that namespace. import ( "fmt" "github.com/vishvananda/netlink/nl" "golang.org/x/sys/unix" ) // These can be replaced by the values from sys/unix when it is next released. const ( _ = iota NETNSA_NSID NETNSA_PID NETNSA_FD ) // GetNetNsIdByPid looks up the network namespace ID for a given pid (really thread id). // Returns -1 if the namespace does not have an ID set. func (h *Handle) GetNetNsIdByPid(pid int) (int, error) { return h.getNetNsId(NETNSA_PID, uint32(pid)) } // GetNetNsIdByPid looks up the network namespace ID for a given pid (really thread id). // Returns -1 if the namespace does not have an ID set. func GetNetNsIdByPid(pid int) (int, error) { return pkgHandle.GetNetNsIdByPid(pid) } // SetNetNSIdByPid sets the ID of the network namespace for a given pid (really thread id). // The ID can only be set for namespaces without an ID already set. func (h *Handle) SetNetNsIdByPid(pid, nsid int) error { return h.setNetNsId(NETNSA_PID, uint32(pid), uint32(nsid)) } // SetNetNSIdByPid sets the ID of the network namespace for a given pid (really thread id). // The ID can only be set for namespaces without an ID already set. func SetNetNsIdByPid(pid, nsid int) error { return pkgHandle.SetNetNsIdByPid(pid, nsid) } // GetNetNsIdByFd looks up the network namespace ID for a given fd. // fd must be an open file descriptor to a namespace file. // Returns -1 if the namespace does not have an ID set. func (h *Handle) GetNetNsIdByFd(fd int) (int, error) { return h.getNetNsId(NETNSA_FD, uint32(fd)) } // GetNetNsIdByFd looks up the network namespace ID for a given fd. // fd must be an open file descriptor to a namespace file. // Returns -1 if the namespace does not have an ID set. func GetNetNsIdByFd(fd int) (int, error) { return pkgHandle.GetNetNsIdByFd(fd) } // SetNetNSIdByFd sets the ID of the network namespace for a given fd. // fd must be an open file descriptor to a namespace file. // The ID can only be set for namespaces without an ID already set. func (h *Handle) SetNetNsIdByFd(fd, nsid int) error { return h.setNetNsId(NETNSA_FD, uint32(fd), uint32(nsid)) } // SetNetNSIdByFd sets the ID of the network namespace for a given fd. // fd must be an open file descriptor to a namespace file. // The ID can only be set for namespaces without an ID already set. func SetNetNsIdByFd(fd, nsid int) error { return pkgHandle.SetNetNsIdByFd(fd, nsid) } // getNetNsId requests the netnsid for a given type-val pair // type should be either NETNSA_PID or NETNSA_FD func (h *Handle) getNetNsId(attrType int, val uint32) (int, error) { req := h.newNetlinkRequest(unix.RTM_GETNSID, unix.NLM_F_REQUEST) rtgen := nl.NewRtGenMsg() req.AddData(rtgen) b := make([]byte, 4) native.PutUint32(b, val) attr := nl.NewRtAttr(attrType, b) req.AddData(attr) msgs, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWNSID) if err != nil { return 0, err } for _, m := range msgs { msg := nl.DeserializeRtGenMsg(m) attrs, err := nl.ParseRouteAttr(m[msg.Len():]) if err != nil { return 0, err } for _, attr := range attrs { switch attr.Attr.Type { case NETNSA_NSID: return int(int32(native.Uint32(attr.Value))), nil } } } return 0, fmt.Errorf("unexpected empty result") } // setNetNsId sets the netnsid for a given type-val pair // type should be either NETNSA_PID or NETNSA_FD // The ID can only be set for namespaces without an ID already set func (h *Handle) setNetNsId(attrType int, val uint32, newnsid uint32) error { req := h.newNetlinkRequest(unix.RTM_NEWNSID, unix.NLM_F_REQUEST|unix.NLM_F_ACK) rtgen := nl.NewRtGenMsg() req.AddData(rtgen) b := make([]byte, 4) native.PutUint32(b, val) attr := nl.NewRtAttr(attrType, b) req.AddData(attr) b1 := make([]byte, 4) native.PutUint32(b1, newnsid) attr1 := nl.NewRtAttr(NETNSA_NSID, b1) req.AddData(attr1) _, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWNSID) return err }