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-rw-r--r--nxcomp/ServerReadBuffer.cpp235
1 files changed, 235 insertions, 0 deletions
diff --git a/nxcomp/ServerReadBuffer.cpp b/nxcomp/ServerReadBuffer.cpp
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--- /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;
+}