Botan::TLS::Datagram_Sequence_Numbers Class Reference

#include <tls_seq_numbers.h>

Inheritance diagram for Botan::TLS::Datagram_Sequence_Numbers:

Public Member Functions
bool	already_seen (uint64_t sequence) const override
uint16_t	current_read_epoch () const override
uint16_t	current_write_epoch () const override
	Datagram_Sequence_Numbers ()
void	new_read_cipher_state () override
void	new_write_cipher_state () override
uint64_t	next_read_sequence () override
uint64_t	next_write_sequence (uint16_t epoch) override
void	read_accept (uint64_t sequence) override
void	reset () override

Detailed Description

Definition at line 87 of file tls_seq_numbers.h.

Constructor & Destructor Documentation

Datagram_Sequence_Numbers()

Botan::TLS::Datagram_Sequence_Numbers::Datagram_Sequence_Numbers ( )

inline

Definition at line 89 of file tls_seq_numbers.h.

{ Datagram_Sequence_Numbers::reset(); }

References reset().

Member Function Documentation

already_seen()

bool Botan::TLS::Datagram_Sequence_Numbers::already_seen ( uint64_t sequence ) const

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 129 of file tls_seq_numbers.h.

                                                          {
         const uint16_t epoch = static_cast<uint16_t>(sequence >> 48);
         const uint64_t record_sequence = sequence & 0x0000FFFFFFFFFFFF;
         const auto window = m_read_windows.find(epoch);
 
         if(window == m_read_windows.end()) {
            return false;
         }
 
         const size_t window_size = sizeof(window->second.bits) * 8;
 
         if(record_sequence > window->second.highest) {
            return false;
         }
 
         const uint64_t offset = window->second.highest - record_sequence;
 
         if(offset >= window_size) {
            return true;  // really old?
         }
 
         return (((window->second.bits >> offset) & 1) == 1);
      }

current_read_epoch()

uint16_t Botan::TLS::Datagram_Sequence_Numbers::current_read_epoch ( ) const

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 112 of file tls_seq_numbers.h.

{ return m_read_epoch; }

current_write_epoch()

uint16_t Botan::TLS::Datagram_Sequence_Numbers::current_write_epoch ( ) const

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 114 of file tls_seq_numbers.h.

{ return m_write_epoch; }

new_read_cipher_state()

void Botan::TLS::Datagram_Sequence_Numbers::new_read_cipher_state ( )

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 100 of file tls_seq_numbers.h.

                                            {
         m_read_epoch = next_epoch(m_read_epoch);
         m_read_windows.try_emplace(m_read_epoch);
         prune_epochs(m_read_windows, m_read_epoch);
      }

new_write_cipher_state()

void Botan::TLS::Datagram_Sequence_Numbers::new_write_cipher_state ( )

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 106 of file tls_seq_numbers.h.

                                             {
         m_write_epoch = next_epoch(m_write_epoch);
         m_write_seqs[m_write_epoch] = 0;
         prune_epochs(m_write_seqs, m_write_epoch);
      }

next_read_sequence()

uint64_t Botan::TLS::Datagram_Sequence_Numbers::next_read_sequence ( )

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 127 of file tls_seq_numbers.h.

{ throw Invalid_State("DTLS uses explicit sequence numbers"); }

next_write_sequence()

uint64_t Botan::TLS::Datagram_Sequence_Numbers::next_write_sequence ( uint16_t epoch )

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 116 of file tls_seq_numbers.h.

                                                            {
         auto i = m_write_seqs.find(epoch);
         if(i == m_write_seqs.end()) {
            throw Invalid_State("DTLS epoch not found");
         }
         if(i->second > 0x0000FFFFFFFFFFFF) {
            throw Invalid_State("DTLS write sequence number overflow");
         }
         return (static_cast<uint64_t>(epoch) << 48) | i->second++;
      }

read_accept()

void Botan::TLS::Datagram_Sequence_Numbers::read_accept ( uint64_t sequence )

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 153 of file tls_seq_numbers.h.

                                                   {
         const uint16_t epoch = static_cast<uint16_t>(sequence >> 48);
         const uint64_t record_sequence = sequence & 0x0000FFFFFFFFFFFF;
         auto& window = m_read_windows[epoch];
         const size_t window_size = sizeof(window.bits) * 8;
 
         if(record_sequence > window.highest) {
            // We've received a later sequence which advances our window
            const uint64_t offset = record_sequence - window.highest;
            window.highest += offset;
 
            if(offset >= window_size) {
               window.bits = 0;
            } else {
               window.bits <<= offset;
            }
 
            window.bits |= 0x01;
         } else {
            const uint64_t offset = window.highest - record_sequence;
 
            if(offset < window_size) {
               // We've received an old sequence but still within our window
               window.bits |= (static_cast<uint64_t>(1) << offset);
            } else {
               // DTLS reconnection: recenter the window on this sequence. Bit 0
               // marks the sequence itself as seen so an immediate replay is
               // detected; the other branches above set this implicitly.
               window.highest = record_sequence;
               window.bits = 1;
            }
         }
      }

reset()

void Botan::TLS::Datagram_Sequence_Numbers::reset ( )

inlineoverridevirtual

Implements Botan::TLS::Connection_Sequence_Numbers.

Definition at line 91 of file tls_seq_numbers.h.

                            {
         m_write_seqs.clear();
         m_write_seqs[0] = 0;
         m_write_epoch = 0;
         m_read_epoch = 0;
         m_read_windows.clear();
         m_read_windows[0] = Replay_Window{};
      }

Referenced by Datagram_Sequence_Numbers().

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The documentation for this class was generated from the following file:

• src/lib/tls/tls12/tls_seq_numbers.h