59 lines
1.5 KiB
Go
59 lines
1.5 KiB
Go
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// +build !windows,!plan9
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package dns
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import (
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"net"
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"syscall"
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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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// setUDPSocketOptions sets the UDP socket options.
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// This function is implemented on a per platform basis. See udp_*.go for more details
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func setUDPSocketOptions(conn *net.UDPConn) error {
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sa, err := getUDPSocketName(conn)
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if err != nil {
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return err
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}
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switch sa.(type) {
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case *syscall.SockaddrInet6:
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v6only, err := getUDPSocketOptions6Only(conn)
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if err != nil {
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return err
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}
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setUDPSocketOptions6(conn)
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if !v6only {
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setUDPSocketOptions4(conn)
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}
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case *syscall.SockaddrInet4:
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setUDPSocketOptions4(conn)
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}
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return nil
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}
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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.WritetTo(), 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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n, _, err := conn.WriteMsgUDP(b, session.context, session.raddr)
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return n, err
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}
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