/*

* Session Tickets

* (C) 2012 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/tls_messages.h>

#include <botan/rng.h>

#include <botan/tls_callbacks.h>

#include <botan/tls_session.h>

#include <botan/tls_session_manager.h>

#include <botan/internal/loadstor.h>

#include <botan/internal/tls_handshake_hash.h>

#include <botan/internal/tls_handshake_io.h>

#include <botan/internal/tls_reader.h>

#include <botan/tls_exceptn.h>

#include <span>

namespace Botan::TLS {

New_Session_Ticket_12::New_Session_Ticket_12(Handshake_IO& io,

                                             Handshake_Hash& hash,

                                             Session_Ticket ticket,

                                             std::chrono::seconds lifetime) :

      m_ticket_lifetime_hint(lifetime), m_ticket(std::move(ticket)) {

   hash.update(io.send(*this));

}

New_Session_Ticket_12::New_Session_Ticket_12(Handshake_IO& io, Handshake_Hash& hash) {

   hash.update(io.send(*this));

}

New_Session_Ticket_12::New_Session_Ticket_12(const std::vector<uint8_t>& buf) {

   if(buf.size() < 6) {

      throw Decoding_Error("Session ticket message too short to be valid");

   }

   TLS_Data_Reader reader("SessionTicket", buf);

   m_ticket_lifetime_hint = std::chrono::seconds(reader.get_uint32_t());

   m_ticket = Session_Ticket(reader.get_range<uint8_t>(2, 0, 65535));

   reader.assert_done();

}

namespace {

template <typename lifetime_t = uint32_t>

void store_lifetime(std::span<uint8_t> sink, std::chrono::seconds lifetime) {

   BOTAN_ARG_CHECK(lifetime.count() >= 0 && lifetime.count() <= std::numeric_limits<lifetime_t>::max(),

                   "Ticket lifetime is out of range");

   store_be(static_cast<lifetime_t>(lifetime.count()), sink.data());

}

}  // namespace

std::vector<uint8_t> New_Session_Ticket_12::serialize() const {

   std::vector<uint8_t> buf(4);

   store_be(static_cast<uint32_t>(m_ticket_lifetime_hint.count()), buf.data());

   append_tls_length_value(buf, m_ticket.get(), 2);

   return buf;

}

#if defined(BOTAN_HAS_TLS_13)

New_Session_Ticket_13::New_Session_Ticket_13(Ticket_Nonce nonce,

                                             const Session& session,

                                             const Session_Handle& handle,

                                             Callbacks& callbacks) :

      m_ticket_lifetime_hint(session.lifetime_hint()),

      m_ticket_age_add(session.session_age_add()),

      m_ticket_nonce(std::move(nonce)),

      m_handle(handle.opaque_handle()) {

   callbacks.tls_modify_extensions(m_extensions, Connection_Side::Server, type());

}

New_Session_Ticket_13::New_Session_Ticket_13(const std::vector<uint8_t>& buf, Connection_Side from) {

   TLS_Data_Reader reader("New_Session_Ticket_13", buf);

   m_ticket_lifetime_hint = std::chrono::seconds(reader.get_uint32_t());

   // RFC 8446 4.6.1

   //    Servers MUST NOT use any value [of ticket_lifetime] greater than 604800

   //    seconds (7 days).

   if(m_ticket_lifetime_hint > std::chrono::days(7)) {

      throw TLS_Exception(Alert::IllegalParameter, "Received a session ticket with lifetime longer than one week.");

   }

   m_ticket_age_add = reader.get_uint32_t();

   m_ticket_nonce = Ticket_Nonce(reader.get_tls_length_value(1));

   m_handle = Opaque_Session_Handle(reader.get_tls_length_value(2));

   m_extensions.deserialize(reader, from, type());

   // RFC 8446 4.6.1

   //    The sole extension currently defined for NewSessionTicket is

   //    "early_data", indicating that the ticket may be used to send 0-RTT

   //    data [...]. Clients MUST ignore unrecognized extensions.

   if(m_extensions.contains_implemented_extensions_other_than({Extension_Code::EarlyData})) {

      throw TLS_Exception(Alert::IllegalParameter, "NewSessionTicket message contained unexpected extension");

   }

   reader.assert_done();

}

std::optional<uint32_t> New_Session_Ticket_13::early_data_byte_limit() const {

   if(!m_extensions.has<EarlyDataIndication>()) {

      return std::nullopt;

   }

   const EarlyDataIndication* ext = m_extensions.get<EarlyDataIndication>();

   BOTAN_ASSERT_NOMSG(ext->max_early_data_size().has_value());

   return ext->max_early_data_size();

}

std::vector<uint8_t> New_Session_Ticket_13::serialize() const {

   std::vector<uint8_t> result(8);

   store_lifetime(std::span(result.data(), 4), m_ticket_lifetime_hint);

   store_be(m_ticket_age_add, result.data() + 4);

   append_tls_length_value(result, m_ticket_nonce.get(), 1);

   append_tls_length_value(result, m_handle.get(), 2);

   // TODO: re-evaluate this construction when reworking message marshalling

   if(m_extensions.empty()) {

      result.push_back(0x00);

      result.push_back(0x00);

   } else {

      result += m_extensions.serialize(Connection_Side::Server);

   }

   return result;

}

#endif

}  // namespace Botan::TLS