Botan::TLS::Datagram_Handshake_IO Class Reference

#include <tls_handshake_io.h>

Inheritance diagram for Botan::TLS::Datagram_Handshake_IO:

Public Types
typedef std::function< void(uint16_t, uint8_t, const std::vector< uint8_t > &)>	writer_fn

Public Member Functions
void	add_record (const std::vector< uint8_t > &record, Record_Type type, uint64_t sequence_number) override
	Datagram_Handshake_IO (writer_fn writer, class Connection_Sequence_Numbers &seq, uint16_t mtu, uint64_t initial_timeout_ms, uint64_t max_timeout_ms)
std::vector< uint8_t >	format (const std::vector< uint8_t > &handshake_msg, Handshake_Type handshake_type) const override
std::pair< Handshake_Type, std::vector< uint8_t > >	get_next_record (bool expecting_ccs) override
Protocol_Version	initial_record_version () const override
std::vector< uint8_t >	send (const Handshake_Message &msg) override
bool	timeout_check () override

Detailed Description

Handshake IO for datagram-based handshakes

Definition at line 95 of file tls_handshake_io.h.

Member Typedef Documentation

writer_fn

typedef std::function<void (uint16_t, uint8_t, const std::vector<uint8_t>&)> Botan::TLS::Datagram_Handshake_IO::writer_fn

Definition at line 98 of file tls_handshake_io.h.

Constructor & Destructor Documentation

Datagram_Handshake_IO()

Botan::TLS::Datagram_Handshake_IO::Datagram_Handshake_IO ( writer_fn  writer, class Connection_Sequence_Numbers &  seq, uint16_t  mtu, uint64_t  initial_timeout_ms, uint64_t  max_timeout_ms  )

inline

Definition at line 100 of file tls_handshake_io.h.

                                                                                                :
         m_seqs(seq),
         m_flights(1),
         m_initial_timeout(initial_timeout_ms),
         m_max_timeout(max_timeout_ms),
         m_send_hs(writer),
         m_mtu(mtu)
         {}

Member Function Documentation

add_record()

void Botan::TLS::Datagram_Handshake_IO::add_record ( const std::vector< uint8_t > &  record, Record_Type  type, uint64_t  sequence_number  )

overridevirtual

Implements Botan::TLS::Handshake_IO.

Definition at line 196 of file tls_handshake_io.cpp.

References Botan::TLS::CHANGE_CIPHER_SPEC, and Botan::load_be< uint16_t >().

   {
   const uint16_t epoch = static_cast<uint16_t>(record_sequence >> 48);

   if(record_type == CHANGE_CIPHER_SPEC)
      {
      // TODO: check this is otherwise empty
      m_ccs_epochs.insert(epoch);
      return;
      }

   const size_t DTLS_HANDSHAKE_HEADER_LEN = 12;

   const uint8_t* record_bits = record.data();
   size_t record_size = record.size();

   while(record_size)
      {
      if(record_size < DTLS_HANDSHAKE_HEADER_LEN)
         return; // completely bogus? at least degenerate/weird

      const uint8_t msg_type = record_bits[0];
      const size_t msg_len = load_be24(&record_bits[1]);
      const uint16_t message_seq = load_be<uint16_t>(&record_bits[4], 0);
      const size_t fragment_offset = load_be24(&record_bits[6]);
      const size_t fragment_length = load_be24(&record_bits[9]);

      const size_t total_size = DTLS_HANDSHAKE_HEADER_LEN + fragment_length;

      if(record_size < total_size)
         throw Decoding_Error("Bad lengths in DTLS header");

      if(message_seq >= m_in_message_seq)
         {
         m_messages[message_seq].add_fragment(&record_bits[DTLS_HANDSHAKE_HEADER_LEN],
                                              fragment_length,
                                              fragment_offset,
                                              epoch,
                                              msg_type,
                                              msg_len);
         }
      else
         {
         // TODO: detect retransmitted flight
         }

      record_bits += total_size;
      record_size -= total_size;
      }
   }

format()

std::vector< uint8_t > Botan::TLS::Datagram_Handshake_IO::format ( const std::vector< uint8_t > &  handshake_msg, Handshake_Type  handshake_type  ) const

overridevirtual

Implements Botan::TLS::Handshake_IO.

Definition at line 383 of file tls_handshake_io.cpp.

References type.

   {
   return format_w_seq(msg, type, m_in_message_seq - 1);
   }

get_next_record()

std::pair< Handshake_Type, std::vector< uint8_t > > Botan::TLS::Datagram_Handshake_IO::get_next_record ( bool  expecting_ccs )

overridevirtual

Returns (HANDSHAKE_NONE, std::vector<>()) if no message currently available

Implements Botan::TLS::Handshake_IO.

Definition at line 250 of file tls_handshake_io.cpp.

References Botan::TLS::HANDSHAKE_CCS, and Botan::TLS::HANDSHAKE_NONE.

   {
   // Expecting a message means the last flight is concluded
   if(!m_flights.rbegin()->empty())
      m_flights.push_back(std::vector<uint16_t>());

   if(expecting_ccs)
      {
      if(!m_messages.empty())
         {
         const uint16_t current_epoch = m_messages.begin()->second.epoch();

         if(m_ccs_epochs.count(current_epoch))
            return std::make_pair(HANDSHAKE_CCS, std::vector<uint8_t>());
         }
      return std::make_pair(HANDSHAKE_NONE, std::vector<uint8_t>());
      }

   auto i = m_messages.find(m_in_message_seq);

   if(i == m_messages.end() || !i->second.complete())
      return std::make_pair(HANDSHAKE_NONE, std::vector<uint8_t>());

   m_in_message_seq += 1;

   return i->second.message();
   }

initial_record_version()

Protocol_Version Botan::TLS::Datagram_Handshake_IO::initial_record_version ( ) const

overridevirtual

Implements Botan::TLS::Handshake_IO.

Definition at line 139 of file tls_handshake_io.cpp.

References Botan::TLS::Protocol_Version::DTLS_V10.

   {
   return Protocol_Version::DTLS_V10;
   }

send()

std::vector< uint8_t > Botan::TLS::Datagram_Handshake_IO::send ( const Handshake_Message &  msg )

overridevirtual

Implements Botan::TLS::Handshake_IO.

Definition at line 391 of file tls_handshake_io.cpp.

References Botan::TLS::CHANGE_CIPHER_SPEC, Botan::TLS::Connection_Sequence_Numbers::current_write_epoch(), Botan::TLS::HANDSHAKE_CCS, Botan::TLS::Handshake_Message::serialize(), and Botan::TLS::Handshake_Message::type().

   {
   const std::vector<uint8_t> msg_bits = msg.serialize();
   const uint16_t epoch = m_seqs.current_write_epoch();
   const Handshake_Type msg_type = msg.type();

   if(msg_type == HANDSHAKE_CCS)
      {
      m_send_hs(epoch, CHANGE_CIPHER_SPEC, msg_bits);
      return std::vector<uint8_t>(); // not included in handshake hashes
      }

   // Note: not saving CCS, instead we know it was there due to change in epoch
   m_flights.rbegin()->push_back(m_out_message_seq);
   m_flight_data[m_out_message_seq] = Message_Info(epoch, msg_type, msg_bits);

   m_out_message_seq += 1;
   m_last_write = steady_clock_ms();
   m_next_timeout = m_initial_timeout;

   return send_message(m_out_message_seq - 1, epoch, msg_type, msg_bits);
   }

timeout_check()

bool Botan::TLS::Datagram_Handshake_IO::timeout_check ( )

overridevirtual

Implements Botan::TLS::Handshake_IO.

Definition at line 174 of file tls_handshake_io.cpp.

   {
   if(m_last_write == 0 || (m_flights.size() > 1 && !m_flights.rbegin()->empty()))
      {
      /*
      If we haven't written anything yet obviously no timeout.
      Also no timeout possible if we are mid-flight,
      */
      return false;
      }

   const uint64_t ms_since_write = steady_clock_ms() - m_last_write;

   if(ms_since_write < m_next_timeout)
      return false;

   retransmit_last_flight();

   m_next_timeout = std::min(2 * m_next_timeout, m_max_timeout);
   return true;
   }

---

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

• src/lib/tls/tls_handshake_io.h
• src/lib/tls/tls_handshake_io.cpp