sec_clr.cpp

伯克利做的SFTP安全文件传输协议

// sec_clr.cc
// code for sec_clr.h
// copyright SafeTP Development Group, Inc., 2000  Terms of use are as specified in license.txt

#include "sec_clr.h"      // this module
#include "datablok.h"     // DataBlock

#include <string.h>       // strcmp


// ------------------ CleartextDataSecurity --------------------------
DataSecurityLevel CleartextDataSecurity::getSupportedProtLevels() const
{
  return DSL_CLEAR;
}

char CleartextDataSecurity::getCodeForLevel(DataSecurityLevel level) const
{
  xassert(level == DSL_CLEAR);
  return 'C';
}

DataSecurityLevel CleartextDataSecurity::getLevelForCode(char code) const
{
  if (code == 'C') {
    return DSL_CLEAR;
  }
  else {
    return DSL_NONE;
  }
}


// --------------------- CleartextControl2 ---------------------------
char const * const CleartextControl2::serverFirst =
  "Cleartext2 first server ADAT";
char const * const CleartextControl2::clientFirst =
  "Cleartext2 first client ADAT";
char const * const CleartextControl2::serverSecond =
  "Cleartext2 second server ADAT";
char const * const CleartextControl2::clientSecond =
  "Cleartext2 second client ADAT";


bool CleartextControl2::hasOutgoingAdat() const
{
  if (isClient) {
    return state==1 || state==3;
  }
  else {    // server
    return state==0 || state==2;
  }
}


void CleartextControl2::getNextOutgoingAdat(DataBlock &block)
{
  if (isClient) {
    switch (state) {
      case 1:
        block.setFromString(clientFirst);
        break;

      case 3:
        block.setFromString(clientSecond);
        break;

      default:
        xassert(!"invalid state");
    }
  }

  else {    // server
    switch (state) {
      case 0:
        block.setFromString(serverFirst);
        break;

      case 2:
        block.setFromString(serverSecond);
        break;

      default:
        xassert(!"invalid state");
    }
  }

  state++;
}


bool CleartextControl2::expectingIncomingAdat() const
{
  if (isClient) {
    return state==0 || state==2;
  }
  else {    // server
    return state==1 || state==3;
  }
}


void CleartextControl2::checkAdat(
  DataBlock const &reallyIs, char const *shouldBe, char const *context)
{
  char const *really = (char const*)reallyIs.getDataC();
  if (0!=strcmp(really, shouldBe)) {
    xsecurity(stringb(context << " should be \"" << shouldBe <<
                      "\" but is \"" << really << "\""));
  }
}


void CleartextControl2::incomingAdat(DataBlock &block)
{
  if (isClient) {
    switch (state) {
      case 0:
        checkAdat(block, serverFirst, "Server's first adat");
        break;

      case 2:
        checkAdat(block, serverSecond, "Server's second adat");
        break;

      default:
        xassert(!"invalid state");
    }
  }

  else {     // server
    switch (state) {
      case 1:
        checkAdat(block, clientFirst, "Client's first adat");
        break;

      case 3:
        checkAdat(block, clientSecond, "Client's second adat");
        break;

      default:
        xassert(!"invalid state");
    }
  }

  state++;
}