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// +build !windows
package dns
import (
"net"
)
// 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 }
// 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.WriteTo(), but uses a *SessionUDP instead of a net.Addr.
func WriteToSessionUDP(conn *net.UDPConn, b []byte, session *SessionUDP) (int, error) {
oob := correctSource(session.context)
n, _, err := conn.WriteMsgUDP(b, oob, session.raddr)
return n, err
}
// correctSource takes oob data and returns new oob data with the Src equal to the Dst
func correctSource(oob []byte) []byte {
dst, err := parseUDPSocketDst(oob)
// If the destination could not be determined, ignore.
if err != nil || dst == nil {
return nil
}
return marshalUDPSocketSrc(dst)
}
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