forked from osmocom/wireshark
385 lines
15 KiB
C
385 lines
15 KiB
C
/* reassemble.h
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* Declarations of outines for {fragment,segment} reassembly
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/* make sure that all flags that are set in a fragment entry is also set for
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* the flags field of fd_head !!!
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*/
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#ifndef REASSEMBLE_H
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#define REASSEMBLE_H
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#include "ws_symbol_export.h"
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/* only in fd_head: packet is defragmented */
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#define FD_DEFRAGMENTED 0x0001
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/* there are overlapping fragments */
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#define FD_OVERLAP 0x0002
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/* overlapping fragments contain different data */
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#define FD_OVERLAPCONFLICT 0x0004
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/* more than one fragment which indicates end-of data */
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#define FD_MULTIPLETAILS 0x0008
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/* fragment starts before the end of the datagram but extends
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past the end of the datagram */
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#define FD_TOOLONGFRAGMENT 0x0010
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/* fragment tvb is subset, don't tvb_free() it */
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#define FD_SUBSET_TVB 0x0020
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/* this flag is used to request fragment_add to continue the reassembly process */
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#define FD_PARTIAL_REASSEMBLY 0x0040
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/* fragment offset is indicated by sequence number and not byte offset
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into the defragmented packet */
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#define FD_BLOCKSEQUENCE 0x0100
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/* if REASSEMBLE_FLAGS_CHECK_DATA_PRESENT is set, and the first fragment is
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* incomplete, this flag is set in the flags word on the fd_head returned.
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*
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* It's all a fudge to preserve historical behaviour.
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*/
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#define FD_DATA_NOT_PRESENT 0x0200
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/* This flag is set in (only) fd_head to denote that datalen has been set to a valid value.
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* It's implied by FD_DEFRAGMENTED (we must know the total length of the
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* datagram if we have defragmented it...)
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*/
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#define FD_DATALEN_SET 0x0400
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typedef struct _fragment_item {
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struct _fragment_item *next;
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guint32 frame; /* XXX - does this apply to reassembly heads? */
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guint32 offset; /* XXX - does this apply to reassembly heads? */
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guint32 len; /* XXX - does this apply to reassembly heads? */
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guint32 fragment_nr_offset; /* offset for frame numbering, for sequences, where the
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* provided fragment number of the first fragment does
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* not start with 0
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* XXX - does this apply only to reassembly heads? */
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guint32 datalen; /* Only valid in first item of list and when
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* flags&FD_DATALEN_SET is set;
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* number of bytes or (if flags&FD_BLOCKSEQUENCE set)
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* segments in the datagram */
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guint32 reassembled_in; /* frame where this PDU was reassembled,
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only valid in the first item of the list
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and when FD_DEFRAGMENTED is set*/
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guint32 flags; /* XXX - do some of these apply only to reassembly
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heads and others only to fragments within
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a reassembly? */
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tvbuff_t *tvb_data;
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/*
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* Null if the reassembly had no error; non-null if it had
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* an error, in which case it's the string for the error.
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*
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* XXX - this is wasted in all but the reassembly head; we
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* should probably have separate data structures for a
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* reassembly and for the fragments in a reassembly.
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*/
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const char *error;
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} fragment_item, fragment_head;
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/*
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* Flags for fragment_add_seq_*
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*/
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/* we don't have any sequence numbers - fragments are assumed to appear in
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* order */
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#define REASSEMBLE_FLAGS_NO_FRAG_NUMBER 0x0001
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/* a special fudge for the 802.11 dissector */
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#define REASSEMBLE_FLAGS_802_11_HACK 0x0002
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/* causes fragment_add_seq_key to check that all the fragment data is present
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* in the tvb, and if not, do something a bit odd. */
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#define REASSEMBLE_FLAGS_CHECK_DATA_PRESENT 0x0004
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/* a function for creating temporary hash keys */
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typedef gpointer (*fragment_temporary_key)(const packet_info *pinfo,
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const guint32 id, const void *data);
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/* a function for creating persistent hash keys */
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typedef gpointer (*fragment_persistent_key)(const packet_info *pinfo,
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const guint32 id, const void *data);
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/*
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* Data structure to keep track of fragments and reassemblies.
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*/
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typedef struct {
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GHashTable *fragment_table;
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GHashTable *reassembled_table;
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fragment_temporary_key temporary_key_func;
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fragment_persistent_key persistent_key_func;
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GDestroyNotify free_temporary_key_func; /* temporary key destruction function */
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} reassembly_table;
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/*
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* Table of functions for a reassembly table.
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*/
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typedef struct {
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/* Functions for fragment table */
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GHashFunc hash_func; /* hash function */
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GEqualFunc equal_func; /* comparison function */
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fragment_temporary_key temporary_key_func; /* temporary key creation function */
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fragment_persistent_key persistent_key_func; /* persistent key creation function */
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GDestroyNotify free_temporary_key_func; /* temporary key destruction function */
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GDestroyNotify free_persistent_key_func; /* persistent key destruction function */
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} reassembly_table_functions;
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/*
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* Tables of functions exported for the benefit of dissectors that
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* don't need special items in their keys.
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*/
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WS_DLL_PUBLIC const reassembly_table_functions
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addresses_reassembly_table_functions; /* keys have endpoint addresses and an ID */
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WS_DLL_PUBLIC const reassembly_table_functions
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addresses_ports_reassembly_table_functions; /* keys have endpoint addresses and ports and an ID */
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/*
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* Initialize/destroy a reassembly table.
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*
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* init: If table doesn't exist: create table;
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* else: just remove any entries;
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* destroy: remove entries and destroy table;
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*/
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WS_DLL_PUBLIC void
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reassembly_table_init(reassembly_table *table,
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const reassembly_table_functions *funcs);
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WS_DLL_PUBLIC void
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reassembly_table_destroy(reassembly_table *table);
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/*
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* This function adds a new fragment to the reassembly table
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* If this is the first fragment seen for this datagram, a new entry
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* is created in the table, otherwise this fragment is just added
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* to the linked list of fragments for this packet.
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* The list of fragments for a specific datagram is kept sorted for
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* easier handling.
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*
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* Returns a pointer to the head of the fragment data list if we have all the
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* fragments, NULL otherwise.
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*/
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WS_DLL_PUBLIC fragment_head *
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fragment_add(reassembly_table *table, tvbuff_t *tvb, const int offset,
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const packet_info *pinfo, const guint32 id, const void *data,
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const guint32 frag_offset, const guint32 frag_data_len,
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const gboolean more_frags);
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WS_DLL_PUBLIC fragment_head *
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fragment_add_multiple_ok(reassembly_table *table, tvbuff_t *tvb,
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const int offset, const packet_info *pinfo,
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const guint32 id, const void *data,
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const guint32 frag_offset,
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const guint32 frag_data_len,
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const gboolean more_frags);
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/*
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* This routine extends fragment_add to use a "reassembled_table"
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* included in the reassembly table.
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*
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* If, after processing this fragment, we have all the fragments, they
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* remove that from the fragment hash table if necessary and add it
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* to the table of reassembled fragments, and return a pointer to the
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* head of the fragment list.
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*/
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WS_DLL_PUBLIC fragment_head *
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fragment_add_check(reassembly_table *table, tvbuff_t *tvb, const int offset,
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const packet_info *pinfo, const guint32 id,
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const void *data, const guint32 frag_offset,
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const guint32 frag_data_len, const gboolean more_frags);
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/* same as fragment_add() but this one assumes frag_number is a block
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sequence number. note that frag_number is 0 for the first fragment. */
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/*
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* These functions add a new fragment to the fragment hash table,
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* assuming that frag_number is a block sequence number (starting from zero for
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* the first fragment of each datagram).
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*
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* If this is the first fragment seen for this datagram, a new
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* "fragment_head" structure is allocated to refer to the reassembled
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* packet, and:
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*
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* if "more_frags" is false, and either we have no sequence numbers, or
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* are using the 802.11 hack, it is assumed that this is the only fragment
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* in the datagram. The structure is not added to the hash
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* table, and not given any fragments to refer to, but is just returned.
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*
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* In this latter case reassembly wasn't done (since there was only one
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* fragment in the packet); dissectors can check the 'next' pointer on the
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* returned list to see if this case was hit or not.
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*
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* Otherwise, this fragment is just added to the linked list of fragments
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* for this packet; the fragment_item is also added to the fragment hash if
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* necessary.
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*
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* If this packet completes assembly, these functions return the head of the
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* fragment data; otherwise, they return null.
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*/
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WS_DLL_PUBLIC fragment_head *
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fragment_add_seq(reassembly_table *table, tvbuff_t *tvb, const int offset,
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const packet_info *pinfo, const guint32 id, const void *data,
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const guint32 frag_number, const guint32 frag_data_len,
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const gboolean more_frags, const guint32 flags);
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/*
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* These routines extend fragment_add_seq to use the "reassembled_table".
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*
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* If, after processing this fragment, we have all the fragments, they
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* remove that from the fragment hash table if necessary and add it
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* to the table of reassembled fragments, and return a pointer to the
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* head of the fragment list.
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*/
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WS_DLL_PUBLIC fragment_head *
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fragment_add_seq_check(reassembly_table *table, tvbuff_t *tvb, const int offset,
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const packet_info *pinfo, const guint32 id,
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const void *data,
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const guint32 frag_number, const guint32 frag_data_len,
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const gboolean more_frags);
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WS_DLL_PUBLIC fragment_head *
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fragment_add_seq_802_11(reassembly_table *table, tvbuff_t *tvb,
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const int offset, const packet_info *pinfo,
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const guint32 id, const void *data,
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const guint32 frag_number, const guint32 frag_data_len,
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const gboolean more_frags);
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WS_DLL_PUBLIC fragment_head *
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fragment_add_seq_next(reassembly_table *table, tvbuff_t *tvb, const int offset,
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const packet_info *pinfo, const guint32 id,
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const void *data, const guint32 frag_data_len,
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const gboolean more_frags);
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WS_DLL_PUBLIC void
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fragment_start_seq_check(reassembly_table *table, const packet_info *pinfo,
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const guint32 id, const void *data,
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const guint32 tot_len);
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WS_DLL_PUBLIC fragment_head *
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fragment_end_seq_next(reassembly_table *table, const packet_info *pinfo,
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const guint32 id, const void *data);
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/* To specify the offset for the fragment numbering, the first fragment is added with 0, and
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* afterwards this offset is set. All additional calls to off_seq_check will calculate
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* the number in sequence in regards to the offset */
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WS_DLL_PUBLIC void
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fragment_add_seq_offset(reassembly_table *table, const packet_info *pinfo, const guint32 id,
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const void *data, const guint32 fragment_offset);
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/* to specify how much to reassemble, for fragmentation where last fragment can not be
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* identified by flags or such.
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* note that for FD_BLOCKSEQUENCE tot_len is the index for the tail fragment.
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* i.e. since the block numbers start at 0, if we specify tot_len==2, that
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* actually means we want to defragment 3 blocks, block 0, 1 and 2.
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*
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*/
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WS_DLL_PUBLIC void
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fragment_set_tot_len(reassembly_table *table, const packet_info *pinfo,
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const guint32 id, const void *data, const guint32 tot_len);
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/* to resad whatever totlen previously set */
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WS_DLL_PUBLIC guint32
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fragment_get_tot_len(reassembly_table *table, const packet_info *pinfo,
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const guint32 id, const void *data);
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/*
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* This function will set the partial reassembly flag(FD_PARTIAL_REASSEMBLY) for a fh.
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* When this function is called, the fh MUST already exist, i.e.
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* the fh MUST be created by the initial call to fragment_add() before
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* this function is called. Also note that this function MUST be called to indicate
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* a fh will be extended (increase the already stored data). After calling this function,
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* and if FD_DEFRAGMENTED is set, the reassembly process will be continued.
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*/
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WS_DLL_PUBLIC void
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fragment_set_partial_reassembly(reassembly_table *table,
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const packet_info *pinfo, const guint32 id,
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const void *data);
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/* This function is used to check if there is partial or completed reassembly state
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* matching this packet. I.e. Are there reassembly going on or not for this packet?
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*/
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WS_DLL_PUBLIC fragment_head *
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fragment_get(reassembly_table *table, const packet_info *pinfo,
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const guint32 id, const void *data);
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/* The same for the reassemble table */
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/* id *must* be the frame number for this to work! */
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WS_DLL_PUBLIC fragment_head *
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fragment_get_reassembled(reassembly_table *table, const guint32 id);
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WS_DLL_PUBLIC fragment_head *
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fragment_get_reassembled_id(reassembly_table *table, const packet_info *pinfo,
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const guint32 id);
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/* This will free up all resources and delete reassembly state for this PDU.
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* Except if the PDU is completely reassembled, then it would NOT deallocate the
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* buffer holding the reassembled data but instead return the TVB
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*
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* So, if you call fragment_delete and it returns non-NULL, YOU are responsible to
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* tvb_free() .
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*/
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WS_DLL_PUBLIC tvbuff_t *
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fragment_delete(reassembly_table *table, const packet_info *pinfo,
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const guint32 id, const void *data);
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/* This struct holds references to all the tree and field handles used when
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* displaying the reassembled fragment tree in the packet details view. A
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* dissector will populate this structure with its own tree and field handles
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* and then invoke show_fragement_tree to have those items added to the packet
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* details tree.
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*/
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typedef struct _fragment_items {
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gint *ett_fragment;
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gint *ett_fragments;
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int *hf_fragments; /* FT_NONE */
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int *hf_fragment; /* FT_FRAMENUM */
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int *hf_fragment_overlap; /* FT_BOOLEAN */
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int *hf_fragment_overlap_conflict; /* FT_BOOLEAN */
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int *hf_fragment_multiple_tails; /* FT_BOOLEAN */
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int *hf_fragment_too_long_fragment; /* FT_BOOLEAN */
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int *hf_fragment_error; /* FT_FRAMENUM */
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int *hf_fragment_count; /* FT_UINT32 */
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int *hf_reassembled_in; /* FT_FRAMENUM */
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int *hf_reassembled_length; /* FT_UINT32 */
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int *hf_reassembled_data; /* FT_BYTES */
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const char *tag;
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} fragment_items;
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WS_DLL_PUBLIC tvbuff_t *
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process_reassembled_data(tvbuff_t *tvb, const int offset, packet_info *pinfo,
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const char *name, fragment_head *fd_head, const fragment_items *fit,
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gboolean *update_col_infop, proto_tree *tree);
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WS_DLL_PUBLIC gboolean
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show_fragment_tree(fragment_head *ipfd_head, const fragment_items *fit,
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proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, proto_item **fi);
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WS_DLL_PUBLIC gboolean
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show_fragment_seq_tree(fragment_head *ipfd_head, const fragment_items *fit,
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proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, proto_item **fi);
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#endif
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