46 lines
1.3 KiB
Go
46 lines
1.3 KiB
Go
// +build !windows
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package dns
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import (
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"net"
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)
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// SessionUDP holds the remote address and the associated
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// out-of-band data.
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type SessionUDP struct {
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raddr *net.UDPAddr
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context []byte
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}
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// RemoteAddr returns the remote network address.
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func (s *SessionUDP) RemoteAddr() net.Addr { return s.raddr }
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// ReadFromSessionUDP acts just like net.UDPConn.ReadFrom(), but returns a session object instead of a
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// net.UDPAddr.
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func ReadFromSessionUDP(conn *net.UDPConn, b []byte) (int, *SessionUDP, error) {
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oob := make([]byte, 40)
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n, oobn, _, raddr, err := conn.ReadMsgUDP(b, oob)
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if err != nil {
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return n, nil, err
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}
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return n, &SessionUDP{raddr, oob[:oobn]}, err
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}
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// WriteToSessionUDP acts just like net.UDPConn.WriteTo(), but uses a *SessionUDP instead of a net.Addr.
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func WriteToSessionUDP(conn *net.UDPConn, b []byte, session *SessionUDP) (int, error) {
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oob := correctSource(session.context)
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n, _, err := conn.WriteMsgUDP(b, oob, session.raddr)
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return n, err
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}
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// correctSource takes oob data and returns new oob data with the Src equal to the Dst
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func correctSource(oob []byte) []byte {
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dst, err := parseUDPSocketDst(oob)
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// If the destination could not be determined, ignore.
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if err != nil || dst == nil {
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return nil
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}
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return marshalUDPSocketSrc(dst)
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}
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