From Paul Ollis:

  epan/sigcomp_state_hdlr.c epan/sigcomp_state_hdlr.h
  ---------------------------------------------------

    Function udvm_state_access:

        1. Removed the state_vars_valid parameter. It is no longer used.

        2. The function now correctly updates each of state_length,
           state_address and state_instruction with saved state value.

           [Previously this was only done for state referenced in the SigComp
            message header.]

        3. Removed code that (incorrectly) read byte_copy_left from UDVM memory
           within the loop that writes the state to UDVM memory.

        4. Removed the code that set the useful values in UDVM memory. This
           should only be done for state referenced in the SigComp message
           header. (The decompress_sigcomp_message function, sets the useful
           values.)


  epan/sigcomp-udvm.c epan/sigcomp-udvm.h
  ---------------------------------------

    Function decompress_sigcomp_message:

        1. Added three new parameters; header_len, byte_code_state_len,
           byte_code_id_len.  The byte_code_state_len and byte_code_id_len
           are used to set the useful values in UDVM memory. The
           header_len is required to calculate the cycles available
           for decompression.

        2. Various minor corrections to spellings, etc in generated
           messages.

        3. Reduced the number of lines of output for print_level_1. Now
           the execution trace shows the instruction name and parameter
           values on one line.

           [This was done because, we found that even at the lowest
           level of detail ethereal became unusably slow; running on
           a 500 MHz SPARC. This seems to be related to the number of
           lines produced by the SigComp trace, which can easily be over
           1000 with the modified code.]

        4. Removed the used of some floating point functions. In all
           cases they were unnecessary and could potentially cause the
           code to produce the wrong results on some platforms (although
           this is unlikely).

        5. The useful values are now set correctly, using the new
           byte_code_state_len and byte_code_id_len parameters.

        6. The message header length is now included in the calculation of
           maximum_UDVM_cycles. Previously, the calculation could underestimate
           the value, resulting in the (small) chance that some legitimate
           messages might fail to decompress.

           Note: The calculation might now slightly over-estimate the cycles
           but this is a reasonable thing to do.

        7. Implemented the PUSH, POP, CALL and RETURN instructions.

           Note: The two SORT instructions and the CRC and SHA-1 instructions
           are still not implemented.

        8. The COPY and COPY-LITERAL instructions now apply the
           byte-copying-rules to the source address as well as the destination
           address.

        9. The COPY-LITERAL and COPY-OFFSET now correctly handle the
           destination operand. Previously, it was possible for the destination
           to be left at byte_copy_right when it should be left at
           byte_copy_left.

        10. All three COPY instructions will now behave correctly if the source
            or destination start at byte_copy_right; i.e. they read/write to
            byte_copy_right, byte_copy_right+1, etc. Previously the parameters
            would wrap to byte_copy_left.

        11. The COPY-OFFSET instruction now correctly calculates the source
            address for all values of offset. Previously a very large offset
            (greater than the circular buffer size) could cause the starting
            position to be mis-calculated.

        12. Modulo 65536 arithmetic has been added in some places where it was
            missing.

            [Only when noticed, we have not been able to check all the code.]

        13. Some redundant code was removed for the INPUT-BITS instruction.
            Also, INPUT-BITS (0, x, x) now correctly discards spare bits when
            the P-bit, has changed.

        14. Corrected the cycles used calculation for the INPUT-BITS
            instruction.

        15. Corrected some minor cases where the used_udvm_cycles was not
            incremented.

            [Not really a problem, but it allowed us to verify correctness with
            some of the SigComp torture tests.]

        16. Removed some redundant code in INPUT-HUFFMAN (and reorganised some
            comments to keep them making sense).


    Function decomp_dispatch_get_bits:

        1. This has been rewritten. The original version could not correctly
           handle requests for more than 8 bits. The new version is cleaner and
           correctly handles all cases.

svn path=/trunk/; revision=14666

1 files changed, 45 insertions, 45 deletions

diff --git a/epan/sigcomp_state_hdlr.h b/epan/sigcomp_state_hdlr.h
index f33e9a1483..29bf893145 100644
--- a/epan/sigcomp_state_hdlr.h
+++ b/epan/sigcomp_state_hdlr.h
@@ -1,45 +1,45 @@
-/* sigcomp_state_hdlr.c

- * Routines making up the State handler of the Univerasl Decompressor Virtual Machine (UDVM) 

- * used for Signaling Compression (SigComp) dissection.

- * Copyright 2004, Anders Broman <anders.broman@ericsson.com>

- *

- * $Id: udvm.c 11445 2004-07-20 19:04:48Z etxrab $

- *

- * Ethereal - Network traffic analyzer

- * By Gerald Combs <gerald@ethereal.com>

- * Copyright 1998 Gerald Combs

- *

- * This program is free software; you can redistribute it and/or

- * modify it under the terms of the GNU General Public License

- * as published by the Free Software Foundation; either version 2

- * of the License, or (at your option) any later version.

- * 

- * This program is distributed in the hope that it will be useful,

- * but WITHOUT ANY WARRANTY; without even the implied warranty of

- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

- * GNU General Public License for more details.

- * 

- * You should have received a copy of the GNU General Public License

- * along with this program; if not, write to the Free Software

- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

- * References:

- * http://www.ietf.org/rfc/rfc3320.txt?number=3320

- * http://www.ietf.org/rfc/rfc3321.txt?number=3321

- * Useful links :

- * http://www.ietf.org/internet-drafts/draft-ietf-rohc-sigcomp-impl-guide-03.txt

- * http://www.ietf.org/internet-drafts/draft-ietf-rohc-sigcomp-sip-01.txt

- */

-

-#ifndef SIGCOMP_STATE_HDLR_H

-#define SIGCOMP_STATE_HDLR_H

-

-extern const value_string result_code_vals[];

-extern int udvm_state_access(tvbuff_t *tvb, proto_tree *tree,guint8 *buff,guint16 p_id_start, guint16 p_id_length, guint16 state_begin, guint16 *state_length, 

-								guint16 *state_address, guint16 state_instruction, gboolean state_vars_valid, gint hf_id);

-

-extern void udvm_state_create(guint8 *state_buff,guint8 *state_identifier_buff,guint16 p_id_length);

-extern void udvm_state_free(guint8 buff[],guint16 p_id_start,guint16 p_id_length);

-

-extern void sigcomp_init_udvm(void);

-#endif 

-/* SIGCOMP_STATE_HDLR_H */

+/* sigcomp_state_hdlr.c
+ * Routines making up the State handler of the Univerasl Decompressor Virtual Machine (UDVM) 
+ * used for Signaling Compression (SigComp) dissection.
+ * Copyright 2004, Anders Broman <anders.broman@ericsson.com>
+ *
+ * $Id: udvm.c 11445 2004-07-20 19:04:48Z etxrab $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * References:
+ * http://www.ietf.org/rfc/rfc3320.txt?number=3320
+ * http://www.ietf.org/rfc/rfc3321.txt?number=3321
+ * Useful links :
+ * http://www.ietf.org/internet-drafts/draft-ietf-rohc-sigcomp-impl-guide-03.txt
+ * http://www.ietf.org/internet-drafts/draft-ietf-rohc-sigcomp-sip-01.txt
+ */
+
+#ifndef SIGCOMP_STATE_HDLR_H
+#define SIGCOMP_STATE_HDLR_H
+
+extern const value_string result_code_vals[];
+extern int udvm_state_access(tvbuff_t *tvb, proto_tree *tree,guint8 *buff,guint16 p_id_start, guint16 p_id_length, guint16 state_begin, guint16 *state_length, 
+								guint16 *state_address, guint16 *state_instruction, gint hf_id);
+
+extern void udvm_state_create(guint8 *state_buff,guint8 *state_identifier_buff,guint16 p_id_length);
+extern void udvm_state_free(guint8 buff[],guint16 p_id_start,guint16 p_id_length);
+
+extern void sigcomp_init_udvm(void);
+#endif 
+/* SIGCOMP_STATE_HDLR_H */