#include <tls_handshake_transitions.h>

Public Member Functions
bool	change_cipher_spec_expected () const

void	confirm_transition_to (Handshake_Type msg_type)

bool	received_handshake_msg (Handshake_Type msg_type) const

void	set_expected_next (const std::vector< Handshake_Type > &msg_types)

void	set_expected_next (Handshake_Type msg_type)

Detailed Description

Manages the expectations for incoming handshake messages in both TLS 1.2 and 1.3. This does not bear any knowledge about the actual state machine but is a mere helper to implement state transition validation.

Definition at line 24 of file tls_handshake_transitions.h.

Member Function Documentation

◆ change_cipher_spec_expected()

bool Botan::TLS::Handshake_Transitions::change_cipher_spec_expected ( ) const

Check whether a Change Cipher Spec must be expected

Definition at line 175 of file tls_handshake_transitions.cpp.

175 {

176 return (bitmask_for_handshake_type(Handshake_Type::HandshakeCCS) & m_hand_expecting_mask) != 0;

177}

Botan::TLS::Handshake_Type::HandshakeCCS

@ HandshakeCCS

Definition tls_magic.h:75

References Botan::TLS::HandshakeCCS.

◆ confirm_transition_to()

void Botan::TLS::Handshake_Transitions::confirm_transition_to ( Handshake_Type msg_type )

Confirm that we were expecting this message type

Parameters

msg_type the message type

Definition at line 131 of file tls_handshake_transitions.cpp.

                                                                         {
   const uint32_t mask = bitmask_for_handshake_type(msg_type);
 
   m_hand_received_mask |= mask;
 
   const bool ok = (m_hand_expecting_mask & mask) != 0;  // overlap?
 
   if(!ok) {
      const uint32_t seen_so_far = m_hand_received_mask & ~mask;
 
      std::ostringstream msg;
 
      msg << "Unexpected state transition in handshake got a " << handshake_type_to_string(msg_type);
 
      if(m_hand_expecting_mask == 0) {
         msg << " not expecting messages";
      } else {
         msg << " expected " << handshake_mask_to_string(m_hand_expecting_mask, '|');
      }
 
      if(seen_so_far != 0) {
         msg << " seen " << handshake_mask_to_string(seen_so_far, '+');
      }
 
      throw Unexpected_Message(msg.str());
   }
 
   /* We don't know what to expect next, so force a call to
      set_expected_next; if it doesn't happen, the next transition
      check will always fail which is what we want.
   */
   m_hand_expecting_mask = 0;
}

References Botan::TLS::handshake_type_to_string().

◆ received_handshake_msg()

bool Botan::TLS::Handshake_Transitions::received_handshake_msg ( Handshake_Type msg_type ) const

Return true iff we have received a particular message already

Parameters

msg_type the message type

Definition at line 125 of file tls_handshake_transitions.cpp.

                                                                                {
   const uint32_t mask = bitmask_for_handshake_type(msg_type);
 
   return (m_hand_received_mask & mask) != 0;
}

◆ set_expected_next() [1/2]

void Botan::TLS::Handshake_Transitions::set_expected_next ( const std::vector< Handshake_Type > & msg_types )

Record that we are expecting one of the enumerated message types next. Note that receiving any of the expected messages in confirm_transition_to resets all the expectations.

Parameters

msg_types the message types

Definition at line 169 of file tls_handshake_transitions.cpp.

                                                                                        {
   for(const auto type : msg_types) {
      set_expected_next(type);
   }
}