| // +build !windows |
| |
| package dns |
| |
| import ( |
| "net" |
| "syscall" |
| ) |
| |
| // SessionUDP holds the remote address and the associated |
| // out-of-band data. |
| type SessionUDP struct { |
| raddr *net.UDPAddr |
| context []byte |
| } |
| |
| // RemoteAddr returns the remote network address. |
| func (s *SessionUDP) RemoteAddr() net.Addr { return s.raddr } |
| |
| // 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 |
| } |
| |
| // ReadFromSessionUDP acts just like net.UDPConn.ReadFrom(), but returns a session object instead of a |
| // net.UDPAddr. |
| func ReadFromSessionUDP(conn *net.UDPConn, b []byte) (int, *SessionUDP, error) { |
| oob := make([]byte, 40) |
| n, oobn, _, raddr, err := conn.ReadMsgUDP(b, oob) |
| if err != nil { |
| return n, nil, err |
| } |
| return n, &SessionUDP{raddr, oob[:oobn]}, err |
| } |
| |
| // WriteToSessionUDP acts just like net.UDPConn.WritetTo(), but uses a *SessionUDP instead of a net.Addr. |
| func WriteToSessionUDP(conn *net.UDPConn, b []byte, session *SessionUDP) (int, error) { |
| n, _, err := conn.WriteMsgUDP(b, session.context, session.raddr) |
| return n, err |
| } |