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[OSC] implement SLIP framing via TCP for OSC-1.1. 

OSC-1.1 requires OSC packets to be double SLIP encoded on a TCP stream
for framing, whereas OSC-1.0 frames packets via a int32 size prefix.

As only either OSC-1.0 or OSC-1.1 will ever be used on the same
connection, the tcp part of the OSC dissector should handle both.
'dissect_osc_tcp' now merely acts as a fork into one of both versions.

Changes:
* Reassembly for OSC-1.0 TCP is left untouched.
* Reassembly for OSC-1.1 TCP is implemented in second reassembly mode.
* OSC is no protocol per se, it's merely an encoding, renamed accordingly.
* Fix logical vs binary OR typo in MIDI pitch bend calculation.

Capture file:
* Mixed framing (OSC-1.0, OSC-1.1) OSC TCP pcap: Bug 11976

Change-Id: I5d26db023ef3ee659ae5a668b1665abef40b54c3
Reviewed-on: https://code.wireshark.org/review/13112
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Hanspeter Portner 2016-01-07 20:05:08 +01:00 committed by Anders Broman
parent fe7cbcad86
commit f83e20202f
1 changed files with 185 additions and 6 deletions
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191
epan/dissectors/packet-osc.c
View File

@ -22,14 +22,28 @@
*/
/*
* Specification 1.1 (http://opensoundcontrol.org/spec-1_1)
* - TCP dissection with: SLIP framing
* Specification 1.0 (http://opensoundcontrol.org/spec-1_0)
* - based on default argument types: i,f,s,b
* - including widely used extension types: T,F,N,I,h,d,t,S,c,r,m
* - TCP dissection with: int32 size prefix framing
* References
* - Schmeder, A., Freed, A., and Wessel, D.,
* "Best practices for Open Sound Control",
* Linux Audio Conference, Utrecht, The Netherlands, 2010.
* - Freed, A., Schmeder, A.,
* "Features and Future of Open Sound Control version 1.1 for NIME",
* NIME Conference 2009.
* - Wright, M., Freed, A.,
* "Open Sound Control: A New Protocol for Communicating with Sound Synthesizers",
* International Computer Music Conference, Thessaloniki, Greece, 1997.
* - https://tools.ietf.org/html/rfc1055 (SLIP)
*/
#include "config.h"
#include <string.h>
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/exceptions.h>
@ -604,7 +618,7 @@ dissect_osc_message(tvbuff_t *tvb, proto_item *ti, proto_tree *osc_tree, gint of
}
case MIDI_STATUS_PITCH_BENDER:
{
const gint bender = (((gint)data2 << 7) || (gint)data1) - 0x2000;
const gint bender = (((gint)data2 << 7) | (gint)data1) - 0x2000;
mi = proto_tree_add_none_format(message_tree, hf_osc_message_midi_type, tvb, offset, 4,
"MIDI: Port %i, Channel %i, %s, %i",
@ -687,7 +701,7 @@ dissect_osc_message(tvbuff_t *tvb, proto_item *ti, proto_tree *osc_tree, gint of
}
case MIDI_STATUS_PITCH_BENDER:
{
const gint bender = (((gint)data2 << 7) || (gint)data1) - 0x2000;
const gint bender = (((gint)data2 << 7) | (gint)data1) - 0x2000;
proto_tree_add_int(midi_tree, hf_osc_message_midi_bender_type, tvb, offset, 2, bender);
offset += 2;
@ -833,7 +847,7 @@ dissect_osc_pdu_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
}
}
/* OSC TCP */
/* OSC TCP (OSC-1.0) */
static guint
get_osc_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
@ -852,13 +866,178 @@ dissect_osc_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *d
}
static int
dissect_osc_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
dissect_osc_tcp_1_0(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
tcp_dissect_pdus(tvb, pinfo, tree, TRUE, 4, get_osc_pdu_len,
dissect_osc_tcp_pdu, data);
return tvb_reported_length(tvb);
}
/* OSC TCP (OSC-1.1) */
#define SLIP_END 0xC0 /* 300 (octal), 192 (decimal), indicates end of packet */
#define SLIP_ESC 0xDB /* 333 (octal), 219 (decimal), indicates byte stuffing */
#define SLIP_END_REPLACE 0xDC /* 334 (octal), 220 (decimal), ESC ESC_END means END data byte */
#define SLIP_ESC_REPLACE 0xDD /* 335 (octal), 221 (decimal), ESC ESC_ESC means ESC data byte */
static inline gint
slip_decoded_len(const guint8 *src, guint available)
{
const guint8 *ptr;
const guint8 *end = src + available;
gint decoded_len = 0;
gboolean escaped = FALSE;
for(ptr = src; ptr < end; ptr++)
{
if(escaped)
{
switch(*ptr)
{
case SLIP_END_REPLACE:
/* fall-through */
case SLIP_ESC_REPLACE:
escaped = FALSE;
decoded_len++;
break;
default:
return -1; /* decode failed */
}
}
else /* !escaped */
{
switch(*ptr)
{
case SLIP_END:
return decoded_len;
case SLIP_ESC:
escaped = TRUE;
break;
default:
decoded_len++;
break;
}
}
}
return -1; /* decode failed */
}
static inline void
slip_decode(guint8 *dst, const guint8 *src, guint available)
{
const guint8 *ptr;
guint8 *tar = dst;
const guint8 *end = src + available;
for(ptr = src; ptr < end; ptr++)
{
switch(*ptr)
{
case SLIP_END:
return;
case SLIP_ESC:
break;
case SLIP_END_REPLACE:
*tar++ = SLIP_END;
break;
case SLIP_ESC_REPLACE:
*tar++ = SLIP_ESC;
break;
default:
*tar++ = *ptr;
break;
}
}
}
static int
dissect_osc_tcp_1_1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
guint offset = 0;
while(offset < tvb_reported_length(tvb))
{
const gint available = tvb_reported_length_remaining(tvb, offset);
const guint8 *encoded_buf = tvb_get_ptr(tvb, offset, -1);
const guint8 *slip_end_found = (const guint8 *)memchr(encoded_buf, SLIP_END, available);
guint encoded_len;
gint decoded_len;
guint8 *decoded_buf;
tvbuff_t *next_tvb;
if(!slip_end_found) /* no SLIP'd stream ending in this chunk */
{
/* we ran out of data: ask for more */
pinfo->desegment_offset = offset;
pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
return (offset + available);
}
encoded_len = (guint)(slip_end_found + 1 - encoded_buf);
if(encoded_len > 1) /* we have a non-empty SLIP'd stream*/
{
decoded_len = slip_decoded_len(encoded_buf, encoded_len);
if(decoded_len != -1) /* is a valid SLIP'd stream */
{
decoded_buf = (guint8 *)g_malloc(decoded_len);
if(decoded_buf)
{
slip_decode(decoded_buf, encoded_buf, encoded_len);
next_tvb = tvb_new_child_real_data(tvb, decoded_buf, decoded_len, decoded_len);
tvb_set_free_cb(next_tvb, g_free);
add_new_data_source(pinfo, next_tvb, "SLIP-decoded Data");
dissect_osc_pdu_common(next_tvb, pinfo, tree, data, 0, decoded_len);
}
else
{
return 0; /* failed to allocate new buffer */
}
}
else
{
return 0; /* failed to decode SLIP'd stream */
}
}
offset += encoded_len;
}
/* end of the tvb coincided with the end of a SLIP'd stream */
return tvb_captured_length(tvb);
}
/* OSC TCP (OSC-1.0, OSC-1.1 fork) */
static int
dissect_osc_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
/*
* int32 size prefix framing (OSC-1.0)
* ... {(int32 size)(OSC packet)} ... {(int32 size)(OSC packet)} ...
*/
/*
* SLIP framing (OSC-1.1)
* ... {SLIP'd(OSC packet)} ... {SLIP'd(OSC)} ...
*/
const guint8 first_byte = tvb_get_guint8(tvb, 0);
const gboolean slip_encoded = (first_byte == SLIP_END) /* empty SLIP frame*/
|| (first_byte == '/') /* SLIP'd OSC message frame */
|| (first_byte == '#'); /* SLIP'd OSC bundle frame */
if(slip_encoded)
{
/* assume SLIP framing (OSC-1.1) */
return dissect_osc_tcp_1_1(tvb, pinfo, tree, data);
}
/* assume int32 size-prefixed framing (OSC-1.0) */
return dissect_osc_tcp_1_0(tvb, pinfo, tree, data);
}
/* OSC UDP */
static int
@ -1114,7 +1293,7 @@ proto_register_osc(void)
module_t *osc_module;
proto_osc = proto_register_protocol("Open Sound Control Protocol", "OSC", "osc");
proto_osc = proto_register_protocol("Open Sound Control Encoding", "OSC", "osc");
proto_register_field_array(proto_osc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));