mirror of
https://github.com/deneraraujo/OpenVPNAdapter.git
synced 2026-04-24 00:00:05 +08:00
Sergey Abramchuk
e2ad2ab5d5
git-subtree-dir: Sources/OpenVPNAdapter/Libraries/Vendors/openvpn git-subtree-split: 554d8b88817d3a7b836e78940ed61bb11ed2bd9b
57 lines
1.8 KiB
C++
57 lines
1.8 KiB
C++
// OpenVPN -- An application to securely tunnel IP networks
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// over a single port, with support for SSL/TLS-based
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// session authentication and key exchange,
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// packet encryption, packet authentication, and
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// packet compression.
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//
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// Copyright (C) 2012-2017 OpenVPN Inc.
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License Version 3
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// as published by the Free Software Foundation.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program in the COPYING file.
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// If not, see <http://www.gnu.org/licenses/>.
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//
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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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