mirror of
https://github.com/deneraraujo/OpenVPNAdapter.git
synced 2026-04-24 00:00:05 +08:00
Sergey Abramchuk
f65d76170b
git-subtree-dir: OpenVPN Adapter/Vendors/openvpn git-subtree-split: da99df69492256d7a18bbea303ae98457782a4bf
39 lines
929 B
C++
39 lines
929 B
C++
// OpenVPN
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// Copyright (C) 2012-2017 OpenVPN Technologies, Inc.
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// All rights reserved
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#ifndef OPENVPN_SSL_IS_OPENVPN_PROTOCOL_H
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#define OPENVPN_SSL_IS_OPENVPN_PROTOCOL_H
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#include <algorithm> // for std::min
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#include <openvpn/common/size.hpp> // for size_t
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namespace openvpn {
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// Peek at the first few bytes of a session and
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// distinguishing between OpenVPN or SSL protocols.
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inline bool is_openvpn_protocol(const unsigned char *p, const size_t len)
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{
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const int CONTROL_HARD_RESET_CLIENT_V2 = 7;
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const int OPCODE_SHIFT = 3;
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const int MIN_INITIAL_PKT_SIZE = 14;
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switch (std::min(len, size_t(3)))
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{
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case 3:
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return p[0] == 0
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&& p[1] >= MIN_INITIAL_PKT_SIZE
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&& p[2] == (CONTROL_HARD_RESET_CLIENT_V2 << OPCODE_SHIFT);
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case 2:
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return p[0] == 0 && p[1] >= MIN_INITIAL_PKT_SIZE;
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case 1:
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return p[0] == 0;
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default:
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return true;
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}
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}
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}
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#endif
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