diff options
Diffstat (limited to 'conn/bind_linux.go')
| -rw-r--r-- | conn/bind_linux.go | 585 |
1 files changed, 0 insertions, 585 deletions
diff --git a/conn/bind_linux.go b/conn/bind_linux.go deleted file mode 100644 index 7b970e6..0000000 --- a/conn/bind_linux.go +++ /dev/null @@ -1,585 +0,0 @@ -/* SPDX-License-Identifier: MIT - * - * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved. - */ - -package conn - -import ( - "errors" - "net" - "strconv" - "sync" - "syscall" - "unsafe" - - "golang.org/x/sys/unix" -) - -type ipv4Source struct { - Src [4]byte - Ifindex int32 -} - -type ipv6Source struct { - src [16]byte - // ifindex belongs in dst.ZoneId -} - -type LinuxSocketEndpoint struct { - mu sync.Mutex - dst [unsafe.Sizeof(unix.SockaddrInet6{})]byte - src [unsafe.Sizeof(ipv6Source{})]byte - isV6 bool -} - -func (endpoint *LinuxSocketEndpoint) Src4() *ipv4Source { return endpoint.src4() } -func (endpoint *LinuxSocketEndpoint) Dst4() *unix.SockaddrInet4 { return endpoint.dst4() } -func (endpoint *LinuxSocketEndpoint) IsV6() bool { return endpoint.isV6 } - -func (endpoint *LinuxSocketEndpoint) src4() *ipv4Source { - return (*ipv4Source)(unsafe.Pointer(&endpoint.src[0])) -} - -func (endpoint *LinuxSocketEndpoint) src6() *ipv6Source { - return (*ipv6Source)(unsafe.Pointer(&endpoint.src[0])) -} - -func (endpoint *LinuxSocketEndpoint) dst4() *unix.SockaddrInet4 { - return (*unix.SockaddrInet4)(unsafe.Pointer(&endpoint.dst[0])) -} - -func (endpoint *LinuxSocketEndpoint) dst6() *unix.SockaddrInet6 { - return (*unix.SockaddrInet6)(unsafe.Pointer(&endpoint.dst[0])) -} - -// LinuxSocketBind uses sendmsg and recvmsg to implement a full bind with sticky sockets on Linux. -type LinuxSocketBind struct { - // mu guards sock4 and sock6 and the associated fds. - // As long as someone holds mu (read or write), the associated fds are valid. - mu sync.RWMutex - sock4 int - sock6 int -} - -func NewLinuxSocketBind() Bind { return &LinuxSocketBind{sock4: -1, sock6: -1} } -func NewDefaultBind() Bind { return NewLinuxSocketBind() } - -var _ Endpoint = (*LinuxSocketEndpoint)(nil) -var _ Bind = (*LinuxSocketBind)(nil) - -func (*LinuxSocketBind) ParseEndpoint(s string) (Endpoint, error) { - var end LinuxSocketEndpoint - addr, err := parseEndpoint(s) - if err != nil { - return nil, err - } - - ipv4 := addr.IP.To4() - if ipv4 != nil { - dst := end.dst4() - end.isV6 = false - dst.Port = addr.Port - copy(dst.Addr[:], ipv4) - end.ClearSrc() - return &end, nil - } - - ipv6 := addr.IP.To16() - if ipv6 != nil { - zone, err := zoneToUint32(addr.Zone) - if err != nil { - return nil, err - } - dst := end.dst6() - end.isV6 = true - dst.Port = addr.Port - dst.ZoneId = zone - copy(dst.Addr[:], ipv6[:]) - end.ClearSrc() - return &end, nil - } - - return nil, errors.New("invalid IP address") -} - -func (bind *LinuxSocketBind) Open(port uint16) ([]ReceiveFunc, uint16, error) { - bind.mu.Lock() - defer bind.mu.Unlock() - - var err error - var newPort uint16 - var tries int - - if bind.sock4 != -1 || bind.sock6 != -1 { - return nil, 0, ErrBindAlreadyOpen - } - - originalPort := port - -again: - port = originalPort - var sock4, sock6 int - // Attempt ipv6 bind, update port if successful. - sock6, newPort, err = create6(port) - if err != nil { - if !errors.Is(err, syscall.EAFNOSUPPORT) { - return nil, 0, err - } - } else { - port = newPort - } - - // Attempt ipv4 bind, update port if successful. - sock4, newPort, err = create4(port) - if err != nil { - if originalPort == 0 && errors.Is(err, syscall.EADDRINUSE) && tries < 100 { - unix.Close(sock6) - tries++ - goto again - } - if !errors.Is(err, syscall.EAFNOSUPPORT) { - unix.Close(sock6) - return nil, 0, err - } - } else { - port = newPort - } - - var fns []ReceiveFunc - if sock4 != -1 { - bind.sock4 = sock4 - fns = append(fns, bind.receiveIPv4) - } - if sock6 != -1 { - bind.sock6 = sock6 - fns = append(fns, bind.receiveIPv6) - } - if len(fns) == 0 { - return nil, 0, syscall.EAFNOSUPPORT - } - return fns, port, nil -} - -func (bind *LinuxSocketBind) SetMark(value uint32) error { - bind.mu.RLock() - defer bind.mu.RUnlock() - - if bind.sock6 != -1 { - err := unix.SetsockoptInt( - bind.sock6, - unix.SOL_SOCKET, - unix.SO_MARK, - int(value), - ) - - if err != nil { - return err - } - } - - if bind.sock4 != -1 { - err := unix.SetsockoptInt( - bind.sock4, - unix.SOL_SOCKET, - unix.SO_MARK, - int(value), - ) - - if err != nil { - return err - } - } - - return nil -} - -func (bind *LinuxSocketBind) Close() error { - // Take a readlock to shut down the sockets... - bind.mu.RLock() - if bind.sock6 != -1 { - unix.Shutdown(bind.sock6, unix.SHUT_RDWR) - } - if bind.sock4 != -1 { - unix.Shutdown(bind.sock4, unix.SHUT_RDWR) - } - bind.mu.RUnlock() - // ...and a write lock to close the fd. - // This ensures that no one else is using the fd. - bind.mu.Lock() - defer bind.mu.Unlock() - var err1, err2 error - if bind.sock6 != -1 { - err1 = unix.Close(bind.sock6) - bind.sock6 = -1 - } - if bind.sock4 != -1 { - err2 = unix.Close(bind.sock4) - bind.sock4 = -1 - } - - if err1 != nil { - return err1 - } - return err2 -} - -func (bind *LinuxSocketBind) receiveIPv4(buf []byte) (int, Endpoint, error) { - bind.mu.RLock() - defer bind.mu.RUnlock() - if bind.sock4 == -1 { - return 0, nil, net.ErrClosed - } - var end LinuxSocketEndpoint - n, err := receive4(bind.sock4, buf, &end) - return n, &end, err -} - -func (bind *LinuxSocketBind) receiveIPv6(buf []byte) (int, Endpoint, error) { - bind.mu.RLock() - defer bind.mu.RUnlock() - if bind.sock6 == -1 { - return 0, nil, net.ErrClosed - } - var end LinuxSocketEndpoint - n, err := receive6(bind.sock6, buf, &end) - return n, &end, err -} - -func (bind *LinuxSocketBind) Send(buff []byte, end Endpoint) error { - nend, ok := end.(*LinuxSocketEndpoint) - if !ok { - return ErrWrongEndpointType - } - bind.mu.RLock() - defer bind.mu.RUnlock() - if !nend.isV6 { - if bind.sock4 == -1 { - return net.ErrClosed - } - return send4(bind.sock4, nend, buff) - } else { - if bind.sock6 == -1 { - return net.ErrClosed - } - return send6(bind.sock6, nend, buff) - } -} - -func (end *LinuxSocketEndpoint) SrcIP() net.IP { - if !end.isV6 { - return net.IPv4( - end.src4().Src[0], - end.src4().Src[1], - end.src4().Src[2], - end.src4().Src[3], - ) - } else { - return end.src6().src[:] - } -} - -func (end *LinuxSocketEndpoint) DstIP() net.IP { - if !end.isV6 { - return net.IPv4( - end.dst4().Addr[0], - end.dst4().Addr[1], - end.dst4().Addr[2], - end.dst4().Addr[3], - ) - } else { - return end.dst6().Addr[:] - } -} - -func (end *LinuxSocketEndpoint) DstToBytes() []byte { - if !end.isV6 { - return (*[unsafe.Offsetof(end.dst4().Addr) + unsafe.Sizeof(end.dst4().Addr)]byte)(unsafe.Pointer(end.dst4()))[:] - } else { - return (*[unsafe.Offsetof(end.dst6().Addr) + unsafe.Sizeof(end.dst6().Addr)]byte)(unsafe.Pointer(end.dst6()))[:] - } -} - -func (end *LinuxSocketEndpoint) SrcToString() string { - return end.SrcIP().String() -} - -func (end *LinuxSocketEndpoint) DstToString() string { - var udpAddr net.UDPAddr - udpAddr.IP = end.DstIP() - if !end.isV6 { - udpAddr.Port = end.dst4().Port - } else { - udpAddr.Port = end.dst6().Port - } - return udpAddr.String() -} - -func (end *LinuxSocketEndpoint) ClearDst() { - for i := range end.dst { - end.dst[i] = 0 - } -} - -func (end *LinuxSocketEndpoint) ClearSrc() { - for i := range end.src { - end.src[i] = 0 - } -} - -func zoneToUint32(zone string) (uint32, error) { - if zone == "" { - return 0, nil - } - if intr, err := net.InterfaceByName(zone); err == nil { - return uint32(intr.Index), nil - } - n, err := strconv.ParseUint(zone, 10, 32) - return uint32(n), err -} - -func create4(port uint16) (int, uint16, error) { - - // create socket - - fd, err := unix.Socket( - unix.AF_INET, - unix.SOCK_DGRAM, - 0, - ) - - if err != nil { - return -1, 0, err - } - - addr := unix.SockaddrInet4{ - Port: int(port), - } - - // set sockopts and bind - - if err := func() error { - if err := unix.SetsockoptInt( - fd, - unix.IPPROTO_IP, - unix.IP_PKTINFO, - 1, - ); err != nil { - return err - } - - return unix.Bind(fd, &addr) - }(); err != nil { - unix.Close(fd) - return -1, 0, err - } - - sa, err := unix.Getsockname(fd) - if err == nil { - addr.Port = sa.(*unix.SockaddrInet4).Port - } - - return fd, uint16(addr.Port), err -} - -func create6(port uint16) (int, uint16, error) { - - // create socket - - fd, err := unix.Socket( - unix.AF_INET6, - unix.SOCK_DGRAM, - 0, - ) - - if err != nil { - return -1, 0, err - } - - // set sockopts and bind - - addr := unix.SockaddrInet6{ - Port: int(port), - } - - if err := func() error { - if err := unix.SetsockoptInt( - fd, - unix.IPPROTO_IPV6, - unix.IPV6_RECVPKTINFO, - 1, - ); err != nil { - return err - } - - if err := unix.SetsockoptInt( - fd, - unix.IPPROTO_IPV6, - unix.IPV6_V6ONLY, - 1, - ); err != nil { - return err - } - - return unix.Bind(fd, &addr) - - }(); err != nil { - unix.Close(fd) - return -1, 0, err - } - - sa, err := unix.Getsockname(fd) - if err == nil { - addr.Port = sa.(*unix.SockaddrInet6).Port - } - - return fd, uint16(addr.Port), err -} - -func send4(sock int, end *LinuxSocketEndpoint, buff []byte) error { - - // construct message header - - cmsg := struct { - cmsghdr unix.Cmsghdr - pktinfo unix.Inet4Pktinfo - }{ - unix.Cmsghdr{ - Level: unix.IPPROTO_IP, - Type: unix.IP_PKTINFO, - Len: unix.SizeofInet4Pktinfo + unix.SizeofCmsghdr, - }, - unix.Inet4Pktinfo{ - Spec_dst: end.src4().Src, - Ifindex: end.src4().Ifindex, - }, - } - - end.mu.Lock() - _, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0) - end.mu.Unlock() - - if err == nil { - return nil - } - - // clear src and retry - - if err == unix.EINVAL { - end.ClearSrc() - cmsg.pktinfo = unix.Inet4Pktinfo{} - end.mu.Lock() - _, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0) - end.mu.Unlock() - } - - return err -} - -func send6(sock int, end *LinuxSocketEndpoint, buff []byte) error { - - // construct message header - - cmsg := struct { - cmsghdr unix.Cmsghdr - pktinfo unix.Inet6Pktinfo - }{ - unix.Cmsghdr{ - Level: unix.IPPROTO_IPV6, - Type: unix.IPV6_PKTINFO, - Len: unix.SizeofInet6Pktinfo + unix.SizeofCmsghdr, - }, - unix.Inet6Pktinfo{ - Addr: end.src6().src, - Ifindex: end.dst6().ZoneId, - }, - } - - if cmsg.pktinfo.Addr == [16]byte{} { - cmsg.pktinfo.Ifindex = 0 - } - - end.mu.Lock() - _, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0) - end.mu.Unlock() - - if err == nil { - return nil - } - - // clear src and retry - - if err == unix.EINVAL { - end.ClearSrc() - cmsg.pktinfo = unix.Inet6Pktinfo{} - end.mu.Lock() - _, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0) - end.mu.Unlock() - } - - return err -} - -func receive4(sock int, buff []byte, end *LinuxSocketEndpoint) (int, error) { - - // construct message header - - var cmsg struct { - cmsghdr unix.Cmsghdr - pktinfo unix.Inet4Pktinfo - } - - size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0) - - if err != nil { - return 0, err - } - end.isV6 = false - - if newDst4, ok := newDst.(*unix.SockaddrInet4); ok { - *end.dst4() = *newDst4 - } - - // update source cache - - if cmsg.cmsghdr.Level == unix.IPPROTO_IP && - cmsg.cmsghdr.Type == unix.IP_PKTINFO && - cmsg.cmsghdr.Len >= unix.SizeofInet4Pktinfo { - end.src4().Src = cmsg.pktinfo.Spec_dst - end.src4().Ifindex = cmsg.pktinfo.Ifindex - } - - return size, nil -} - -func receive6(sock int, buff []byte, end *LinuxSocketEndpoint) (int, error) { - - // construct message header - - var cmsg struct { - cmsghdr unix.Cmsghdr - pktinfo unix.Inet6Pktinfo - } - - size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0) - - if err != nil { - return 0, err - } - end.isV6 = true - - if newDst6, ok := newDst.(*unix.SockaddrInet6); ok { - *end.dst6() = *newDst6 - } - - // update source cache - - if cmsg.cmsghdr.Level == unix.IPPROTO_IPV6 && - cmsg.cmsghdr.Type == unix.IPV6_PKTINFO && - cmsg.cmsghdr.Len >= unix.SizeofInet6Pktinfo { - end.src6().src = cmsg.pktinfo.Addr - end.dst6().ZoneId = cmsg.pktinfo.Ifindex - } - - return size, nil -} |