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032fbabc82
Previously, the oob data was just stored and sent to WriteMsgUDP but it ignores the Src field when writing. Instead, now it is setting the Src to the original Dst and handling IPv4 IPs over IPv6 correctly.
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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