Merge branch 'nxcomp'

1 files changed, 235 insertions, 0 deletions

diff --git a/nxcomp/ServerReadBuffer.cpp b/nxcomp/ServerReadBuffer.cpp
new file mode 100644
index 000000000..53c1dec57
--- /dev/null
+++ b/nxcomp/ServerReadBuffer.cpp
@@ -0,0 +1,235 @@
+/**************************************************************************/
+/*                                                                        */
+/* Copyright (c) 2001, 2010 NoMachine, http://www.nomachine.com/.         */
+/*                                                                        */
+/* NXCOMP, NX protocol compression and NX extensions to this software     */
+/* are copyright of NoMachine. Redistribution and use of the present      */
+/* software is allowed according to terms specified in the file LICENSE   */
+/* which comes in the source distribution.                                */
+/*                                                                        */
+/* Check http://www.nomachine.com/licensing.html for applicability.       */
+/*                                                                        */
+/* NX and NoMachine are trademarks of Medialogic S.p.A.                   */
+/*                                                                        */
+/* All rights reserved.                                                   */
+/*                                                                        */
+/**************************************************************************/
+
+#include "ServerReadBuffer.h"
+#include "ServerChannel.h"
+
+//
+// Set the verbosity level.
+//
+
+#define PANIC
+#define WARNING
+#undef  TEST
+#undef  DEBUG
+
+unsigned int ServerReadBuffer::suggestedLength(unsigned int pendingLength)
+{
+  //
+  // Always read all the data that
+  // is available.
+  //
+
+  int readable = transport_ -> readable();
+
+  unsigned int readLength = (readable == -1 ? 0 : (unsigned int) readable);
+
+  if (readLength < pendingLength)
+  {
+    readLength = pendingLength;
+  }
+
+  //
+  // Even if the readable data is not
+  // enough to make a complete message,
+  // resize the buffer to accomodate
+  // it all.
+  //
+
+  if (pendingLength < remaining_)
+  {
+    readLength = remaining_;
+  }
+
+  return readLength;
+}  
+
+int ServerReadBuffer::locateMessage(const unsigned char *start,
+                                        const unsigned char *end,
+                                            unsigned int &controlLength,
+                                                unsigned int &dataLength,
+                                                    unsigned int &trailerLength)
+{
+  unsigned int size = end - start;
+
+  #ifdef TEST
+  *logofs << "ServerReadBuffer: Locating message for FD#"
+          << transport_ -> fd() << " with " << size
+          << " bytes.\n" << logofs_flush;
+  #endif
+
+  if (firstMessage_)
+  {
+    if (size < 8)
+    {
+      remaining_ = 8 - size;
+
+      #ifdef TEST
+      *logofs << "ServerReadBuffer: No message was located "
+              << "with remaining " << remaining_ << ".\n"
+              << logofs_flush;
+      #endif
+
+      return 0;
+    }
+
+    dataLength = 8 + (GetUINT(start + 6, bigEndian_) << 2);
+  }
+  else
+  {
+    if (size < 32)
+    {
+      remaining_ = 32 - size;
+
+      #ifdef TEST
+      *logofs << "ServerReadBuffer: No message was located "
+              << "with remaining " << remaining_ << ".\n"
+              << logofs_flush;
+      #endif
+
+      return 0;
+    }
+
+    if (*start == 1)
+    {
+      dataLength = 32 + (GetULONG(start + 4, bigEndian_) << 2);
+    }
+    else
+    {
+      dataLength = 32;
+    }
+
+    if (dataLength < 32)
+    {
+      #ifdef TEST
+      *logofs << "ServerReadBuffer: WARNING! Assuming length 32 "
+              << "for suspicious message of length " << dataLength
+              << ".\n" << logofs_flush;
+      #endif
+
+      dataLength = 32;
+    }
+  }
+
+  #ifdef TEST
+  *logofs << "ServerReadBuffer: Length of the next message is "
+          << dataLength << ".\n" << logofs_flush;
+  #endif
+
+  if (size < dataLength)
+  {
+    remaining_ = dataLength - size;
+
+    #ifdef TEST
+    *logofs << "ServerReadBuffer: No message was located "
+            << "with remaining " << remaining_ << ".\n"
+            << logofs_flush;
+    #endif
+
+    return 0;
+  }
+
+  firstMessage_ = 0;
+
+  controlLength = 0;
+  trailerLength = 0;
+
+  remaining_ = 0;
+
+  #ifdef TEST
+  *logofs << "ServerReadBuffer: Located message with "
+          << "remaining " << remaining_ << ".\n"
+          << logofs_flush;
+  #endif
+
+  return 1;
+}
+
+//
+// Check if the data already read contains a
+// message matching the opcode and sequence,
+// starting at the given offset.
+//
+
+unsigned char *ServerReadBuffer::peekMessage(unsigned int &offset, unsigned char opcode,
+                                                 unsigned short sequence)
+{
+  #ifdef TEST
+  *logofs << "ServerReadBuffer: Peeking message "
+          << "for FD#" << transport_ -> fd() << " with size "
+          << length_ << " offset " << offset << " opcode "
+          << (unsigned int) opcode << " and sequence "
+          << sequence << ".\n" << logofs_flush;
+  #endif
+
+  if (firstMessage_)
+  {
+    return NULL;
+  }
+
+  unsigned char *next = buffer_ + start_ + offset;
+  unsigned char *end  = buffer_ + start_ + length_;
+
+  int found = 0;
+
+  while (end - next >= 32)
+  {
+    #ifdef DEBUG
+    *logofs << "ServerReadBuffer: Checking opcode "
+            << (unsigned int) *next << " sequence "
+            << GetUINT(next + 2, bigEndian_)
+            << " at " << next - buffer_ + start_
+            << ".\n" << logofs_flush;
+    #endif
+
+    if (*next == opcode && GetUINT(next + 2, bigEndian_) == sequence)
+    {
+      found = 1;
+
+      break;
+    }
+    else if (*next == 1)
+    {
+      next += (32 + (GetULONG(next + 4, bigEndian_) << 2));
+    }
+    else
+    {
+      next += 32;
+    }
+  }
+
+  offset = next - buffer_ + start_;
+
+  if (found == 1)
+  {
+    #ifdef TEST
+    *logofs << "ServerReadBuffer: Found message at "
+            << "offset " << next - buffer_ + start_
+            << ".\n" << logofs_flush;
+    #endif
+
+    return next;
+  }
+
+  #ifdef TEST
+  *logofs << "ServerReadBuffer: Quitting loop at "
+          << "offset " << next - buffer_ + start_
+          << ".\n" << logofs_flush;
+  #endif
+
+  return NULL;
+}