/* reassemble.h * Declarations of outines for {fragment,segment} reassembly * * $Id: reassemble.h,v 1.6 2002/04/17 08:25:05 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* make sure that all flags that are set in a fragment entry is also set for * the flags field of fd_head !!! */ /* only in fd_head: packet is defragmented */ #define FD_DEFRAGMENTED 0x0001 /* there are overlapping fragments */ #define FD_OVERLAP 0x0002 /* overlapping fragments contain different data */ #define FD_OVERLAPCONFLICT 0x0004 /* more than one fragment which indicates end-of data */ #define FD_MULTIPLETAILS 0x0008 /* fragment contains data past the end of the datagram */ #define FD_TOOLONGFRAGMENT 0x0010 /* fragment data not alloced, fd->data pointing to fd_head->data+fd->offset */ #define FD_NOT_MALLOCED 0x0020 /* this flag is used to request fragment_add to continue the reassembly process */ #define FD_PARTIAL_REASSEMBLY 0x0040 /* fragment offset is indicated by sequence number and not byte offset into the defragmented packet */ #define FD_BLOCKSEQUENCE 0x0100 typedef struct _fragment_data { struct _fragment_data *next; guint32 frame; guint32 offset; guint32 len; guint32 datalen; /*Only valid in first item of list */ guint32 flags; unsigned char *data; } fragment_data; /* * Initialize a fragment table. */ void fragment_table_init(GHashTable **fragment_table); /* * Initialize a reassembled-packet table. */ void reassembled_table_init(GHashTable **reassembled_table); /* * Free up all space allocated for fragment keys and data. */ void reassemble_init(void); /* * This function adds a new fragment to the fragment hash table. * If this is the first fragment seen for this datagram, a new entry * is created in the hash table, otherwise this fragment is just added * to the linked list of fragments for this packet. * The list of fragments for a specific datagram is kept sorted for * easier handling. * * Returns a pointer to the head of the fragment data list if we have all the * fragments, NULL otherwise. */ fragment_data *fragment_add(tvbuff_t *tvb, int offset, packet_info *pinfo, guint32 id, GHashTable *fragment_table, guint32 frag_offset, guint32 frag_data_len, gboolean more_frags); /* same as fragment_add() but this one assumes frag_number is a block sequence number. note that frag_number is 0 for the first fragment. */ fragment_data *fragment_add_seq(tvbuff_t *tvb, int offset, packet_info *pinfo, guint32 id, GHashTable *fragment_table, guint32 frag_number, guint32 frag_data_len, gboolean more_frags); /* * This function adds a new fragment to the fragment hash table. * If this is the first fragment seen for this datagram, a new * "fragment_data" structure is allocated to refer to the reassembled, * packet, and: * * if "more_frags" is false, the structure is not added to * the hash table, and not given any fragments to refer to, * but is just returned; * * if "more_frags" is true, this fragment is added to the linked * list of fragments for this packet, and the "fragment_data" * structure is put into the hash table. * * Otherwise, this fragment is just added to the linked list of fragments * for this packet. * * Returns a pointer to the head of the fragment data list, and removes * that from the fragment hash table if necessary and adds it to the * table of reassembled fragments, if we have all the fragments or if * this is the only fragment and "more_frags" is false, returns NULL * otherwise. * * This function assumes frag_number being a block sequence number. * The bsn for the first block is 0. */ fragment_data * fragment_add_seq_check(tvbuff_t *tvb, int offset, packet_info *pinfo, guint32 id, GHashTable *fragment_table, GHashTable *reassembled_table, guint32 frag_number, guint32 frag_data_len, gboolean more_frags); /* to specify how much to reassemble, for fragmentation where last fragment can not be * identified by flags or such. * note that for FD_BLOCKSEQUENCE tot_len is the index for the tail fragment. * i.e. since the block numbers start at 0, if we specify tot_len==2, that * actually means we want to defragment 3 blocks, block 0, 1 and 2. * */ void fragment_set_tot_len(packet_info *pinfo, guint32 id, GHashTable *fragment_table, guint32 tot_len); /* * This function will set the partial reassembly flag(FD_PARTIAL_REASSEMBLY) for a fh. * When this function is called, the fh MUST already exist, i.e. * the fh MUST be created by the initial call to fragment_add() before * this function is called. Also note that this function MUST be called to indicate * a fh will be extended (increase the already stored data). After calling this function, * and if FD_DEFRAGMENTED is set, the reassembly process will be continued. */ void fragment_set_partial_reassembly(packet_info *pinfo, guint32 id, GHashTable *fragment_table); /* This function is used to check if there is partial or completed reassembly state * matching this packet. I.e. Are there reassembly going on or not for this packet? */ fragment_data * fragment_get(packet_info *pinfo, guint32 id, GHashTable *fragment_table); /* This will free up all resources and delete reassembly state for this PDU. * Except if the PDU is completely reassembled, then it would NOT deallocate the * buffer holding the reassembled data but instead return the pointer to that * buffer. * * So, if you call fragment_delete and it returns non-NULL, YOU are responsible to * g_free() that buffer. */ unsigned char * fragment_delete(packet_info *pinfo, guint32 id, GHashTable *fragment_table);