84 lines
2.8 KiB
C++
84 lines
2.8 KiB
C++
#pragma once
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/** A packet to be transmitted or received over the VPN socket */
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#include <cstdlib>
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#include <memory>
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#include "ip_header.hpp"
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/** VPN packet layout:
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*
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* +-------+-------+-------+-------+-------+-------+-------+-------+
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* | 1B | 1B | 1B | 1B | 1B | 1B | 1B | 1B |
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* +-------+-------+-------+-------+-------+-------+-------+-------+
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* | Sequence number [4B] | Sending timestamp (μs) [4B] |
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* +---------------------------------------------------------------+
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* | Nested packet (payload) |
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* +---------------------------------------------------------------+
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*/
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class VpnPeer;
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class VpnPacket {
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public:
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static const size_t VPN_HEADER_BYTES;
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VpnPacket(size_t mtu);
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~VpnPacket();
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/// Set packet peer -- used for sequence numbers
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void set_peer(std::shared_ptr<VpnPeer> peer) { _peer = peer; }
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/// Try to parse the packet as IPv6, return `false` upon failure.
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bool parse_as_ipv6();
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bool ipv6_parsed() const { return _ipv6_parsed; }
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const IPv6Header& get_ipv6_header() const { return _ipv6_header; }
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const char* get_payload() const { return _data + VPN_HEADER_BYTES; }
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char* get_payload() { return _data + VPN_HEADER_BYTES; }
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size_t get_payload_space() const {
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return _data_space - VPN_HEADER_BYTES; }
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size_t get_payload_size() const {
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return _data_size - VPN_HEADER_BYTES; }
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void set_payload_size(size_t payload_size) {
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_data_size = payload_size + VPN_HEADER_BYTES; }
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const char* get_data() const { return _data; }
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char* get_data() { return _data; }
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size_t get_data_space() const { return _data_space; }
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size_t get_data_size() const { return _data_size; }
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void set_data_size(size_t data_size) { _data_size = data_size; }
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uint32_t get_seqno() const;
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uint32_t get_sending_timestamp() const;
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uint32_t get_reception_timestamp() const { return _reception_timestamp; }
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/** Fill the headers of the packet. This method must be called as close
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* to the time the packet is actually sent as possible, as it handles
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* timestamps. */
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void prepare_for_sending();
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/** Do what must be done at reception, eg. keep the reception
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* timestamp. This method must be called as close to the time the
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* packet is actually received as possible, as it handles timestamps.
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*/
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void upon_reception();
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private: // methods
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inline uint32_t next_seqno();
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private:
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std::shared_ptr<VpnPeer> _peer;
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char* _data;
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size_t _data_space, _data_size;
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bool _ipv6_parsed;
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IPv6Header _ipv6_header;
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uint32_t _reception_timestamp;
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static uint32_t _next_general_seqno;
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};
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