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// +build !windows,!plan9
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
}
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