2 * Declarations of outines for {fragment,segment} reassembly
4 * $Id: reassemble.h,v 1.4 2002/02/03 23:28:38 guy Exp $
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@ethereal.com>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
25 /* make sure that all flags that are set in a fragment entry is also set for
26 * the flags field of fd_head !!!
29 /* only in fd_head: packet is defragmented */
30 #define FD_DEFRAGMENTED 0x0001
32 /* there are overlapping fragments */
33 #define FD_OVERLAP 0x0002
35 /* overlapping fragments contain different data */
36 #define FD_OVERLAPCONFLICT 0x0004
38 /* more than one fragment which indicates end-of data */
39 #define FD_MULTIPLETAILS 0x0008
41 /* fragment contains data past the end of the datagram */
42 #define FD_TOOLONGFRAGMENT 0x0010
44 /* fragment data not alloced, fd->data pointing to fd_head->data+fd->offset */
45 #define FD_NOT_MALLOCED 0x0020
47 /* this flag is used to request fragment_add to continue the reassembly process */
48 #define FD_PARTIAL_REASSEMBLY 0x0040
50 /* fragment offset is indicated by sequence number and not byte offset
51 into the defragmented packet */
52 #define FD_BLOCKSEQUENCE 0x0100
54 typedef struct _fragment_data {
55 struct _fragment_data *next;
59 guint32 datalen; /*Only valid in first item of list */
65 * Initialize a fragment table.
67 void fragment_table_init(GHashTable **fragment_table);
70 * Free up all space allocated for fragment keys and data.
72 void reassemble_init(void);
75 * This function adds a new fragment to the fragment hash table.
76 * If this is the first fragment seen for this datagram, a new entry
77 * is created in the hash table, otherwise this fragment is just added
78 * to the linked list of fragments for this packet.
79 * The list of fragments for a specific datagram is kept sorted for
82 * Returns a pointer to the head of the fragment data list if we have all the
83 * fragments, NULL otherwise.
85 fragment_data *fragment_add(tvbuff_t *tvb, int offset, packet_info *pinfo,
86 guint32 id, GHashTable *fragment_table, guint32 frag_offset,
87 guint32 frag_data_len, gboolean more_frags);
89 /* same as fragment_add() but this one assumes frag_offset is a block
90 sequence number. note that frag_offset is 0 for the first fragment. */
91 fragment_data *fragment_add_seq(tvbuff_t *tvb, int offset, packet_info *pinfo,
92 guint32 id, GHashTable *fragment_table, guint32 frag_offset,
93 guint32 frag_data_len, gboolean more_frags);
95 /* to specify how much to reassemble, for fragmentation where last fragment can not be
96 * identified by flags or such.
97 * note that for FD_BLOCKSEQUENCE tot_len is the index for the tail fragment.
98 * i.e. since the block numbers start at 0, if we specify tot_len==2, that
99 * actually means we want to defragment 3 blocks, block 0, 1 and 2.
103 fragment_set_tot_len(packet_info *pinfo, guint32 id, GHashTable *fragment_table,
106 * This function will set the partial reassembly flag(FD_PARTIAL_REASSEMBLY) for a fh.
107 * When this function is called, the fh MUST already exist, i.e.
108 * the fh MUST be created by the initial call to fragment_add() before
109 * this function is called. Also note that this function MUST be called to indicate
110 * a fh will be extended (increase the already stored data). After calling this function,
111 * and if FD_DEFRAGMENTED is set, the reassembly process will be continued.
114 fragment_set_partial_reassembly(packet_info *pinfo, guint32 id, GHashTable *fragment_table);
116 /* This function is used to check if there is partial or completed reassembly state
117 * matching this packet. I.e. Are there reassembly going on or not for this packet?
120 fragment_get(packet_info *pinfo, guint32 id, GHashTable *fragment_table);
122 /* This will free up all resources and delete reassembly state for this PDU.
123 * Except if the PDU is completely reassembled, then it would NOT deallocate the
124 * buffer holding the reassembled data but instead return the pointer to that
127 * So, if you call fragment_delete and it returns non-NULL, YOU are responsible to
128 * g_free() that buffer.
131 fragment_delete(packet_info *pinfo, guint32 id, GHashTable *fragment_table);