1 files changed, 124 insertions, 0 deletions
diff --git a/epan/stream.h b/epan/stream.h
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+++ b/epan/stream.h
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+/** @file
+ *
+ * Definititions for handling circuit-switched protocols
+ * which are handled as streams, and don't have lengths
+ * and IDs such as are required for reassemble.h
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef STREAM_H
+#define STREAM_H
+
+#include <epan/tvbuff.h>
+#include <epan/reassemble.h>
+#include "ws_symbol_export.h"
+
+struct _fragment_items;
+
+/* A stream represents the concept of an arbitrary stream of data,
+   divided up into frames for transmission, where the frames have
+   little or no correspondence to the PDUs of the protocol being
+   streamed, and those PDUs are just delineated by a magic number.
+
+   For example, we stream H.223 over IAX2. IAX2 has no concept of
+   H.223 PDUs and just divides the H.223 stream into 160-byte
+   frames. H.223 PDUs are delineated by two-byte magic numbers (which
+   may, of course, straddle an IAX2 frame boundary).
+
+   Essentially we act as a wrapper to reassemble.h, by making up
+   PDU ids and keeping some additional data on fragments to allow the
+   PDUs to be defragmented again.
+*/
+
+
+/* A stream_t represents a stream. There might be one or two streams
+   in a circuit, depending on whether that circuit is mono- or bi-directional.
+*/
+typedef struct stream stream_t;
+
+/* Fragments in a PDU are represented using a stream_pdu_fragment_t,
+   and placed in a linked-list with other fragments in the PDU.
+
+   (They're also placed in a hash so we can find them again later)
+*/
+typedef struct stream_pdu_fragment stream_pdu_fragment_t;
+
+
+struct conversation;
+
+/* initialise a new stream. Call this when you first identify a distinct
+ * stream. The conversation pointer is just used as a key to look up the stream.
+ */
+WS_DLL_PUBLIC stream_t *stream_new ( const struct conversation *conv, int p2p_dir );
+
+/* retrieve a previously-created stream.
+ *
+ * Returns null if no matching stream was found.
+ */
+WS_DLL_PUBLIC stream_t *find_stream ( const struct conversation *conv, int p2p_dir );
+
+
+
+/* see if we've seen this fragment before.
+
+   The framenum and offset are just hash keys, so can be any values unique
+   to this frame, but the idea is that you use the number of the frame being
+   disassembled, and the byte-offset within that frame.
+*/
+WS_DLL_PUBLIC stream_pdu_fragment_t *stream_find_frag( stream_t *stream, guint32 framenum, guint32 offset );
+
+/* add a new fragment to the fragment tables for the stream. The framenum and
+ * offset are keys allowing future access with stream_find_frag(), tvb is the
+ * fragment to be added, and pinfo is the information for the frame containing
+ * this fragment. more_frags should be set if this is the final fragment in the
+ * PDU.
+ *
+ * * the fragment must be later in the stream than any previous fragment
+ *   (ie, framenum.offset must be greater than those passed on the previous
+ *   call)
+ *
+ * This essentially means that you can only add fragments on the first pass
+ * through the stream.
+ */
+WS_DLL_PUBLIC stream_pdu_fragment_t *stream_add_frag( stream_t *stream, guint32 framenum, guint32 offset,
+					tvbuff_t *tvb, packet_info *pinfo, gboolean more_frags );
+
+/* Get the length of a fragment previously found by stream_find_frag().
+ */
+extern guint32 stream_get_frag_length( const stream_pdu_fragment_t *frag);
+
+/* Get a handle on the top of the chain of fragment_datas underlying this PDU
+ * frag can be any fragment within a PDU, and it will always return the head of
+ * the chain
+ *
+ * Returns NULL until the last fragment is added.
+ */
+extern fragment_head *stream_get_frag_data( const stream_pdu_fragment_t *frag);
+
+/*
+ * Process reassembled data; if this is the last fragment, put the fragment
+ * information into the protocol tree, and construct a tvbuff with the
+ * reassembled data, otherwise just put a "reassembled in" item into the
+ * protocol tree.
+ */
+WS_DLL_PUBLIC tvbuff_t *stream_process_reassembled(
+    tvbuff_t *tvb, int offset, packet_info *pinfo,
+    const char *name, const stream_pdu_fragment_t *frag,
+    const struct _fragment_items *fit,
+    gboolean *update_col_infop, proto_tree *tree);
+
+/* Get the PDU number. PDUs are numbered from zero within a stream.
+ * frag can be any fragment within a PDU.
+ */
+extern guint32 stream_get_pdu_no( const stream_pdu_fragment_t *frag);
+
+/* initialise the stream routines */
+void stream_init( void );
+void stream_cleanup( void );
+
+#endif /* STREAM_H */