2 * Declarations of outines for {fragment,segment} reassembly
4 * $Id: reassemble.h,v 1.6 2002/04/17 08:25:05 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 * Initialize a reassembled-packet table.
72 void reassembled_table_init(GHashTable **reassembled_table);
75 * Free up all space allocated for fragment keys and data.
77 void reassemble_init(void);
80 * This function adds a new fragment to the fragment hash table.
81 * If this is the first fragment seen for this datagram, a new entry
82 * is created in the hash table, otherwise this fragment is just added
83 * to the linked list of fragments for this packet.
84 * The list of fragments for a specific datagram is kept sorted for
87 * Returns a pointer to the head of the fragment data list if we have all the
88 * fragments, NULL otherwise.
90 fragment_data *fragment_add(tvbuff_t *tvb, int offset, packet_info *pinfo,
91 guint32 id, GHashTable *fragment_table, guint32 frag_offset,
92 guint32 frag_data_len, gboolean more_frags);
94 /* same as fragment_add() but this one assumes frag_number is a block
95 sequence number. note that frag_number is 0 for the first fragment. */
96 fragment_data *fragment_add_seq(tvbuff_t *tvb, int offset, packet_info *pinfo,
97 guint32 id, GHashTable *fragment_table, guint32 frag_number,
98 guint32 frag_data_len, gboolean more_frags);
101 * This function adds a new fragment to the fragment hash table.
102 * If this is the first fragment seen for this datagram, a new
103 * "fragment_data" structure is allocated to refer to the reassembled,
106 * if "more_frags" is false, the structure is not added to
107 * the hash table, and not given any fragments to refer to,
108 * but is just returned;
110 * if "more_frags" is true, this fragment is added to the linked
111 * list of fragments for this packet, and the "fragment_data"
112 * structure is put into the hash table.
114 * Otherwise, this fragment is just added to the linked list of fragments
117 * Returns a pointer to the head of the fragment data list, and removes
118 * that from the fragment hash table if necessary and adds it to the
119 * table of reassembled fragments, if we have all the fragments or if
120 * this is the only fragment and "more_frags" is false, returns NULL
123 * This function assumes frag_number being a block sequence number.
124 * The bsn for the first block is 0.
127 fragment_add_seq_check(tvbuff_t *tvb, int offset, packet_info *pinfo,
128 guint32 id, GHashTable *fragment_table,
129 GHashTable *reassembled_table, guint32 frag_number,
130 guint32 frag_data_len, gboolean more_frags);
132 /* to specify how much to reassemble, for fragmentation where last fragment can not be
133 * identified by flags or such.
134 * note that for FD_BLOCKSEQUENCE tot_len is the index for the tail fragment.
135 * i.e. since the block numbers start at 0, if we specify tot_len==2, that
136 * actually means we want to defragment 3 blocks, block 0, 1 and 2.
140 fragment_set_tot_len(packet_info *pinfo, guint32 id, GHashTable *fragment_table,
143 * This function will set the partial reassembly flag(FD_PARTIAL_REASSEMBLY) for a fh.
144 * When this function is called, the fh MUST already exist, i.e.
145 * the fh MUST be created by the initial call to fragment_add() before
146 * this function is called. Also note that this function MUST be called to indicate
147 * a fh will be extended (increase the already stored data). After calling this function,
148 * and if FD_DEFRAGMENTED is set, the reassembly process will be continued.
151 fragment_set_partial_reassembly(packet_info *pinfo, guint32 id, GHashTable *fragment_table);
153 /* This function is used to check if there is partial or completed reassembly state
154 * matching this packet. I.e. Are there reassembly going on or not for this packet?
157 fragment_get(packet_info *pinfo, guint32 id, GHashTable *fragment_table);
159 /* This will free up all resources and delete reassembly state for this PDU.
160 * Except if the PDU is completely reassembled, then it would NOT deallocate the
161 * buffer holding the reassembled data but instead return the pointer to that
164 * So, if you call fragment_delete and it returns non-NULL, YOU are responsible to
165 * g_free() that buffer.
168 fragment_delete(packet_info *pinfo, guint32 id, GHashTable *fragment_table);