mirror of
https://github.com/OpenVPN/openvpn3.git
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0c0af6781e
When receiving packed from tun which size exceeds mssfix value minus encap overhead, send ICMP "destination unreachable" / "fragmentation needed" (for IPv4) or "packet too big" (for IPv6) response. This is required for non-TCP based protocols, since for TCP we alter MSS in SYN segments. Signed-off-by: Lev Stipakov <lev@openvpn.net>
68 lines
1.7 KiB
C++
68 lines
1.7 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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// Define the ICMPv4 header
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#pragma once
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#include <cstdint> // for std::uint32_t, uint16_t, uint8_t
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#include <openvpn/ip/ip4.hpp>
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#pragma pack(push)
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#pragma pack(1)
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namespace openvpn {
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struct ICMPv4 {
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enum {
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ECHO_REQUEST = 8,
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ECHO_REPLY = 0,
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DEST_UNREACH = 3,
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FRAG_NEEDED = 4,
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MIN_DATA_SIZE = 8
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};
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struct IPv4Header head;
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union {
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struct {
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std::uint8_t type;
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std::uint8_t code;
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};
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std::uint16_t type_code;
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};
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std::uint16_t checksum;
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union {
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struct {
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std::uint16_t id;
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std::uint16_t seq_num;
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};
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struct {
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std::uint16_t unused;
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std::uint16_t nexthop_mtu;
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};
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};
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};
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}
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#pragma pack(pop)
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