diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/udp_linux.go')
| -rw-r--r-- | vendor/github.com/miekg/dns/udp_linux.go | 220 |
1 files changed, 0 insertions, 220 deletions
diff --git a/vendor/github.com/miekg/dns/udp_linux.go b/vendor/github.com/miekg/dns/udp_linux.go deleted file mode 100644 index 13747ed34..000000000 --- a/vendor/github.com/miekg/dns/udp_linux.go +++ /dev/null @@ -1,220 +0,0 @@ -// +build linux,!appengine - -package dns - -// See: -// * http://stackoverflow.com/questions/3062205/setting-the-source-ip-for-a-udp-socket and -// * http://blog.powerdns.com/2012/10/08/on-binding-datagram-udp-sockets-to-the-any-addresses/ -// -// Why do we need this: When listening on 0.0.0.0 with UDP so kernel decides what is the outgoing -// interface, this might not always be the correct one. This code will make sure the egress -// packet's interface matched the ingress' one. - -import ( - "net" - "syscall" - "unsafe" - - "github.com/miekg/dns/internal/socket" -) - -const ( - sizeofInet6Pktinfo = 0x14 - sizeofInetPktinfo = 0xc - protocolIP = 0 - protocolIPv6 = 41 -) - -type inetPktinfo struct { - Ifindex int32 - Spec_dst [4]byte /* in_addr */ - Addr [4]byte /* in_addr */ -} - -type inet6Pktinfo struct { - Addr [16]byte /* in6_addr */ - Ifindex int32 -} - -type inetControlMessage struct { - Src net.IP // source address, specifying only - Dst net.IP // destination address, receiving only -} - -// setUDPSocketOptions sets the UDP socket options. -// This function is implemented on a per platform basis. See udp_*.go for more details -func setUDPSocketOptions(conn *net.UDPConn) error { - sa, err := getUDPSocketName(conn) - if err != nil { - return err - } - switch sa.(type) { - case *syscall.SockaddrInet6: - v6only, err := getUDPSocketOptions6Only(conn) - if err != nil { - return err - } - setUDPSocketOptions6(conn) - if !v6only { - setUDPSocketOptions4(conn) - } - case *syscall.SockaddrInet4: - setUDPSocketOptions4(conn) - } - return nil -} - -// setUDPSocketOptions4 prepares the v4 socket for sessions. -func setUDPSocketOptions4(conn *net.UDPConn) error { - file, err := conn.File() - if err != nil { - return err - } - if err := syscall.SetsockoptInt(int(file.Fd()), syscall.IPPROTO_IP, syscall.IP_PKTINFO, 1); err != nil { - file.Close() - return err - } - // Calling File() above results in the connection becoming blocking, we must fix that. - // See https://github.com/miekg/dns/issues/279 - err = syscall.SetNonblock(int(file.Fd()), true) - if err != nil { - file.Close() - return err - } - file.Close() - return nil -} - -// setUDPSocketOptions6 prepares the v6 socket for sessions. -func setUDPSocketOptions6(conn *net.UDPConn) error { - file, err := conn.File() - if err != nil { - return err - } - if err := syscall.SetsockoptInt(int(file.Fd()), syscall.IPPROTO_IPV6, syscall.IPV6_RECVPKTINFO, 1); err != nil { - file.Close() - return err - } - err = syscall.SetNonblock(int(file.Fd()), true) - if err != nil { - file.Close() - return err - } - file.Close() - return nil -} - -// getUDPSocketOption6Only return true if the socket is v6 only and false when it is v4/v6 combined -// (dualstack). -func getUDPSocketOptions6Only(conn *net.UDPConn) (bool, error) { - file, err := conn.File() - if err != nil { - return false, err - } - // dual stack. See http://stackoverflow.com/questions/1618240/how-to-support-both-ipv4-and-ipv6-connections - v6only, err := syscall.GetsockoptInt(int(file.Fd()), syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY) - if err != nil { - file.Close() - return false, err - } - file.Close() - return v6only == 1, nil -} - -func getUDPSocketName(conn *net.UDPConn) (syscall.Sockaddr, error) { - file, err := conn.File() - if err != nil { - return nil, err - } - defer file.Close() - return syscall.Getsockname(int(file.Fd())) -} - -// marshalInetPacketInfo marshals a ipv4 control message, returning -// the byte slice for the next marshal, if any -func marshalInetPacketInfo(b []byte, cm *inetControlMessage) []byte { - m := socket.ControlMessage(b) - m.MarshalHeader(protocolIP, syscall.IP_PKTINFO, sizeofInetPktinfo) - if cm != nil { - pi := (*inetPktinfo)(unsafe.Pointer(&m.Data(sizeofInetPktinfo)[0])) - if ip := cm.Src.To4(); ip != nil { - copy(pi.Spec_dst[:], ip) - } - } - return m.Next(sizeofInetPktinfo) -} - -// marshalInet6PacketInfo marshals a ipv6 control message, returning -// the byte slice for the next marshal, if any -func marshalInet6PacketInfo(b []byte, cm *inetControlMessage) []byte { - m := socket.ControlMessage(b) - m.MarshalHeader(protocolIPv6, syscall.IPV6_PKTINFO, sizeofInet6Pktinfo) - if cm != nil { - pi := (*inet6Pktinfo)(unsafe.Pointer(&m.Data(sizeofInet6Pktinfo)[0])) - if ip := cm.Src.To16(); ip != nil && ip.To4() == nil { - copy(pi.Addr[:], ip) - } - } - return m.Next(sizeofInet6Pktinfo) -} - -func parseInetPacketInfo(cm *inetControlMessage, b []byte) { - pi := (*inetPktinfo)(unsafe.Pointer(&b[0])) - if len(cm.Dst) < net.IPv4len { - cm.Dst = make(net.IP, net.IPv4len) - } - copy(cm.Dst, pi.Addr[:]) -} - -func parseInet6PacketInfo(cm *inetControlMessage, b []byte) { - pi := (*inet6Pktinfo)(unsafe.Pointer(&b[0])) - if len(cm.Dst) < net.IPv6len { - cm.Dst = make(net.IP, net.IPv6len) - } - copy(cm.Dst, pi.Addr[:]) -} - -// parseUDPSocketDst takes out-of-band data from ReadMsgUDP and parses it for -// the Dst address -func parseUDPSocketDst(oob []byte) (net.IP, error) { - cm := new(inetControlMessage) - ms, err := socket.ControlMessage(oob).Parse() - if err != nil { - return nil, err - } - for _, m := range ms { - lvl, typ, l, err := m.ParseHeader() - if err != nil { - return nil, err - } - if lvl == protocolIPv6 { // IPv6 - if typ == syscall.IPV6_PKTINFO && l >= sizeofInet6Pktinfo { - parseInet6PacketInfo(cm, m.Data(l)) - } - } else if lvl == protocolIP { // IPv4 - if typ == syscall.IP_PKTINFO && l >= sizeofInetPktinfo { - parseInetPacketInfo(cm, m.Data(l)) - } - } - } - return cm.Dst, nil -} - -// marshalUDPSocketSrc takes the given src address and returns out-of-band data -// to give to WriteMsgUDP -func marshalUDPSocketSrc(src net.IP) []byte { - var oob []byte - // If the dst is definitely an ipv6, then use ipv6 control to respond - // otherwise use ipv4 because the ipv6 marshal ignores ipv4 messages. - // See marshalInet6PacketInfo - cm := new(inetControlMessage) - cm.Src = src - if src.To4() == nil { - oob = make([]byte, socket.ControlMessageSpace(sizeofInet6Pktinfo)) - marshalInet6PacketInfo(oob, cm) - } else { - oob = make([]byte, socket.ControlMessageSpace(sizeofInetPktinfo)) - marshalInetPacketInfo(oob, cm) - } - return oob -} |