forked from osmocom/wireshark
![Evan Huus](/assets/img/avatar_default.png)
Trust that the files in epan/ immediately (not dissectors) know what they're doing so just blindly convert them to captured length. Change-Id: I872f7d58b2e15ae82c75fd56f4873996fbc97be7 Reviewed-on: https://code.wireshark.org/review/9083 Reviewed-by: Evan Huus <eapache@gmail.com>
2467 lines
70 KiB
C
2467 lines
70 KiB
C
/* reassemble.c
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* Routines 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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#include "config.h"
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#include <string.h>
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#include <epan/packet.h>
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#include <epan/exceptions.h>
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#include <epan/reassemble.h>
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#include <epan/tvbuff-int.h>
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/*
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* Functions for reassembly tables where the endpoint addresses, and a
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* fragment ID, are used as the key.
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*/
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typedef struct _fragment_addresses_key {
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address src;
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address dst;
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guint32 id;
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} fragment_addresses_key;
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static guint
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fragment_addresses_hash(gconstpointer k)
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{
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const fragment_addresses_key* key = (const fragment_addresses_key*) k;
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guint hash_val;
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/*
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int i;
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*/
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hash_val = 0;
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/* More than likely: in most captures src and dst addresses are the
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same, and would hash the same.
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We only use id as the hash as an optimization.
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for (i = 0; i < key->src.len; i++)
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hash_val += key->src.data[i];
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for (i = 0; i < key->dst.len; i++)
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hash_val += key->dst.data[i];
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*/
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hash_val += key->id;
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return hash_val;
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}
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static gint
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fragment_addresses_equal(gconstpointer k1, gconstpointer k2)
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{
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const fragment_addresses_key* key1 = (const fragment_addresses_key*) k1;
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const fragment_addresses_key* key2 = (const fragment_addresses_key*) k2;
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/*
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* key.id is the first item to compare since it's the item most
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* likely to differ between sessions, thus short-circuiting
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* the comparison of addresses.
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*/
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return (key1->id == key2->id) &&
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(ADDRESSES_EQUAL(&key1->src, &key2->src)) &&
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(ADDRESSES_EQUAL(&key1->dst, &key2->dst));
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}
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/*
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* Create a fragment key for temporary use; it can point to non-
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* persistent data, and so must only be used to look up and
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* delete entries, not to add them.
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*/
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static gpointer
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fragment_addresses_temporary_key(const packet_info *pinfo, const guint32 id,
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const void *data _U_)
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{
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fragment_addresses_key *key = g_slice_new(fragment_addresses_key);
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/*
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* Do a shallow copy of the addresses.
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*/
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key->src = pinfo->src;
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key->dst = pinfo->dst;
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key->id = id;
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return (gpointer)key;
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}
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/*
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* Create a fragment key for permanent use; it must point to persistent
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* data, so that it can be used to add entries.
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*/
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static gpointer
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fragment_addresses_persistent_key(const packet_info *pinfo, const guint32 id,
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const void *data _U_)
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{
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fragment_addresses_key *key = g_slice_new(fragment_addresses_key);
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/*
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* Do a deep copy of the addresses.
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*/
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COPY_ADDRESS(&key->src, &pinfo->src);
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COPY_ADDRESS(&key->dst, &pinfo->dst);
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key->id = id;
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return (gpointer)key;
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}
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static void
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fragment_addresses_free_temporary_key(gpointer ptr)
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{
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fragment_addresses_key *key = (fragment_addresses_key *)ptr;
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if(key)
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g_slice_free(fragment_addresses_key, key);
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}
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static void
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fragment_addresses_free_persistent_key(gpointer ptr)
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{
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fragment_addresses_key *key = (fragment_addresses_key *)ptr;
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if(key){
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/*
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* Free up the copies of the addresses from the old key.
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*/
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g_free((gpointer)key->src.data);
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g_free((gpointer)key->dst.data);
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g_slice_free(fragment_addresses_key, key);
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}
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}
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const reassembly_table_functions
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addresses_reassembly_table_functions = {
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fragment_addresses_hash,
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fragment_addresses_equal,
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fragment_addresses_temporary_key,
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fragment_addresses_persistent_key,
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fragment_addresses_free_temporary_key,
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fragment_addresses_free_persistent_key
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};
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/*
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* Functions for reassembly tables where the endpoint addresses and ports,
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* and a fragment ID, are used as the key.
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*/
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typedef struct _fragment_addresses_ports_key {
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address src_addr;
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address dst_addr;
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guint32 src_port;
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guint32 dst_port;
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guint32 id;
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} fragment_addresses_ports_key;
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static guint
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fragment_addresses_ports_hash(gconstpointer k)
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{
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const fragment_addresses_ports_key* key = (const fragment_addresses_ports_key*) k;
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guint hash_val;
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/*
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int i;
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*/
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hash_val = 0;
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/* More than likely: in most captures src and dst addresses and ports
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are the same, and would hash the same.
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We only use id as the hash as an optimization.
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for (i = 0; i < key->src.len; i++)
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hash_val += key->src_addr.data[i];
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for (i = 0; i < key->dst.len; i++)
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hash_val += key->dst_addr.data[i];
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hash_val += key->src_port;
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hash_val += key->dst_port;
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*/
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hash_val += key->id;
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return hash_val;
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}
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static gint
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fragment_addresses_ports_equal(gconstpointer k1, gconstpointer k2)
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{
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const fragment_addresses_ports_key* key1 = (const fragment_addresses_ports_key*) k1;
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const fragment_addresses_ports_key* key2 = (const fragment_addresses_ports_key*) k2;
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/*
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* key.id is the first item to compare since it's the item most
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* likely to differ between sessions, thus short-circuiting
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* the comparison of addresses and ports.
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*/
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return (key1->id == key2->id) &&
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(ADDRESSES_EQUAL(&key1->src_addr, &key2->src_addr)) &&
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(ADDRESSES_EQUAL(&key1->dst_addr, &key2->dst_addr)) &&
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(key1->src_port == key2->src_port) &&
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(key1->dst_port == key2->dst_port);
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}
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/*
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* Create a fragment key for temporary use; it can point to non-
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* persistent data, and so must only be used to look up and
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* delete entries, not to add them.
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*/
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static gpointer
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fragment_addresses_ports_temporary_key(const packet_info *pinfo, const guint32 id,
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const void *data _U_)
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{
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fragment_addresses_ports_key *key = g_slice_new(fragment_addresses_ports_key);
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/*
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* Do a shallow copy of the addresses.
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*/
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key->src_addr = pinfo->src;
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key->dst_addr = pinfo->dst;
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key->src_port = pinfo->srcport;
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key->dst_port = pinfo->destport;
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key->id = id;
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return (gpointer)key;
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}
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/*
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* Create a fragment key for permanent use; it must point to persistent
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* data, so that it can be used to add entries.
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*/
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static gpointer
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fragment_addresses_ports_persistent_key(const packet_info *pinfo,
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const guint32 id, const void *data _U_)
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{
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fragment_addresses_ports_key *key = g_slice_new(fragment_addresses_ports_key);
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/*
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* Do a deep copy of the addresses.
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*/
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COPY_ADDRESS(&key->src_addr, &pinfo->src);
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COPY_ADDRESS(&key->dst_addr, &pinfo->dst);
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key->src_port = pinfo->srcport;
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key->dst_port = pinfo->destport;
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key->id = id;
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return (gpointer)key;
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}
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static void
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fragment_addresses_ports_free_temporary_key(gpointer ptr)
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{
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fragment_addresses_ports_key *key = (fragment_addresses_ports_key *)ptr;
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if(key)
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g_slice_free(fragment_addresses_ports_key, key);
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}
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static void
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fragment_addresses_ports_free_persistent_key(gpointer ptr)
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{
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fragment_addresses_ports_key *key = (fragment_addresses_ports_key *)ptr;
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if(key){
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/*
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* Free up the copies of the addresses from the old key.
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*/
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g_free((gpointer)key->src_addr.data);
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g_free((gpointer)key->dst_addr.data);
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g_slice_free(fragment_addresses_ports_key, key);
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}
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}
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const reassembly_table_functions
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addresses_ports_reassembly_table_functions = {
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fragment_addresses_ports_hash,
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fragment_addresses_ports_equal,
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fragment_addresses_ports_temporary_key,
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fragment_addresses_ports_persistent_key,
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fragment_addresses_ports_free_temporary_key,
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fragment_addresses_ports_free_persistent_key
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};
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typedef struct _reassembled_key {
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guint32 id;
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guint32 frame;
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} reassembled_key;
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static gint
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reassembled_equal(gconstpointer k1, gconstpointer k2)
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{
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const reassembled_key* key1 = (const reassembled_key*) k1;
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const reassembled_key* key2 = (const reassembled_key*) k2;
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/*
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* We assume that the frame numbers are unlikely to be equal,
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* so we check them first.
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*/
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return key1->frame == key2->frame && key1->id == key2->id;
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}
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static guint
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reassembled_hash(gconstpointer k)
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{
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const reassembled_key* key = (const reassembled_key*) k;
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return key->frame;
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}
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/*
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* For a fragment hash table entry, free the associated fragments.
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* The entry value (fd_chain) is freed herein and the entry is freed
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* when the key freeing routine is called (as a consequence of returning
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* TRUE from this function).
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*/
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static gboolean
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free_all_fragments(gpointer key_arg _U_, gpointer value, gpointer user_data _U_)
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{
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fragment_head *fd_head;
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fragment_item *tmp_fd;
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/* g_hash_table_new_full() was used to supply a function
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* to free the key and anything to which it points
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*/
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for (fd_head = (fragment_head *)value; fd_head != NULL; fd_head = tmp_fd) {
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tmp_fd=fd_head->next;
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if(fd_head->tvb_data && !(fd_head->flags&FD_SUBSET_TVB))
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tvb_free(fd_head->tvb_data);
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g_slice_free(fragment_item, fd_head);
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}
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return TRUE;
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}
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/* ------------------------- */
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static fragment_head *new_head(const guint32 flags)
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{
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fragment_head *fd_head;
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/* If head/first structure in list only holds no other data than
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* 'datalen' then we don't have to change the head of the list
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* even if we want to keep it sorted
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*/
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fd_head=g_slice_new0(fragment_head);
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fd_head->flags=flags;
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return fd_head;
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}
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#define FD_VISITED_FREE 0xffff
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/*
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* For a reassembled-packet hash table entry, free the fragment data
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* to which the value refers and also the key itself.
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*/
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static gboolean
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free_all_reassembled_fragments(gpointer key_arg, gpointer value,
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gpointer user_data)
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{
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GPtrArray *allocated_fragments = (GPtrArray *) user_data;
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fragment_head *fd_head;
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for (fd_head = (fragment_head *)value; fd_head != NULL; fd_head = fd_head->next) {
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/*
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* A reassembled packet is inserted into the
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* hash table once for every frame that made
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* up the reassembled packet; add first seen
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* fragments to array and later free them in
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* free_fragments()
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*/
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if (fd_head->flags != FD_VISITED_FREE) {
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if (fd_head->flags & FD_SUBSET_TVB)
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fd_head->tvb_data = NULL;
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g_ptr_array_add(allocated_fragments, fd_head);
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fd_head->flags = FD_VISITED_FREE;
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}
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}
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g_slice_free(reassembled_key, (reassembled_key *)key_arg);
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return TRUE;
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}
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static void
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free_fragments(gpointer data, gpointer user_data _U_)
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{
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fragment_item *fd_head = (fragment_item *) data;
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if (fd_head->tvb_data)
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tvb_free(fd_head->tvb_data);
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g_slice_free(fragment_item, fd_head);
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}
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/*
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* Initialize a reassembly table, with specified functions.
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*/
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void
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reassembly_table_init(reassembly_table *table,
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const reassembly_table_functions *funcs)
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{
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if (table->temporary_key_func == NULL)
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table->temporary_key_func = funcs->temporary_key_func;
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if (table->persistent_key_func == NULL)
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table->persistent_key_func = funcs->persistent_key_func;
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if (table->free_temporary_key_func == NULL)
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table->free_temporary_key_func = funcs->free_temporary_key_func;
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if (table->fragment_table != NULL) {
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/*
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* The fragment hash table exists.
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*
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* Remove all entries and free fragment data for each entry.
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*
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* The keys, and anything to which they point, are freed by
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* calling the table's key freeing function. The values
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* are freed in free_all_fragments().
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*/
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g_hash_table_foreach_remove(table->fragment_table,
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free_all_fragments, NULL);
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} else {
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/* The fragment table does not exist. Create it */
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table->fragment_table = g_hash_table_new_full(funcs->hash_func,
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funcs->equal_func, funcs->free_persistent_key_func, NULL);
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}
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if (table->reassembled_table != NULL) {
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GPtrArray *allocated_fragments;
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/*
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* The reassembled-packet hash table exists.
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*
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* Remove all entries and free reassembled packet
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* data and key for each entry.
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*/
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allocated_fragments = g_ptr_array_new();
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g_hash_table_foreach_remove(table->reassembled_table,
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free_all_reassembled_fragments, allocated_fragments);
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g_ptr_array_foreach(allocated_fragments, free_fragments, NULL);
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g_ptr_array_free(allocated_fragments, TRUE);
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} else {
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/* The fragment table does not exist. Create it */
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table->reassembled_table = g_hash_table_new(reassembled_hash,
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reassembled_equal);
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}
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}
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/*
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* Destroy a reassembly table.
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*/
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void
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reassembly_table_destroy(reassembly_table *table)
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{
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/*
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* Clear the function pointers.
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*/
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table->temporary_key_func = NULL;
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table->persistent_key_func = NULL;
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table->free_temporary_key_func = NULL;
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if (table->fragment_table != NULL) {
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/*
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* The fragment hash table exists.
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*
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* Remove all entries and free fragment data for each entry.
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*
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* The keys, and anything to which they point, are freed by
|
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* calling the table's key freeing function. The values
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* are freed in free_all_fragments().
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*/
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g_hash_table_foreach_remove(table->fragment_table,
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free_all_fragments, NULL);
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/*
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* Now destroy the hash table.
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*/
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g_hash_table_destroy(table->fragment_table);
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table->fragment_table = NULL;
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}
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if (table->reassembled_table != NULL) {
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GPtrArray *allocated_fragments;
|
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/*
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* The reassembled-packet hash table exists.
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*
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* Remove all entries and free reassembled packet
|
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* data and key for each entry.
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*/
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allocated_fragments = g_ptr_array_new();
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g_hash_table_foreach_remove(table->reassembled_table,
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free_all_reassembled_fragments, allocated_fragments);
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g_ptr_array_foreach(allocated_fragments, free_fragments, NULL);
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g_ptr_array_free(allocated_fragments, TRUE);
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/*
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* Now destroy the hash table.
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*/
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g_hash_table_destroy(table->reassembled_table);
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table->reassembled_table = NULL;
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}
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}
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|
|
/*
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* Look up an fd_head in the fragment table, optionally returning the key
|
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* for it.
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*/
|
|
static fragment_head *
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lookup_fd_head(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data, gpointer *orig_keyp)
|
|
{
|
|
gpointer key;
|
|
gpointer value;
|
|
|
|
/* Create key to search hash with */
|
|
key = table->temporary_key_func(pinfo, id, data);
|
|
|
|
/*
|
|
* Look up the reassembly in the fragment table.
|
|
*/
|
|
if (!g_hash_table_lookup_extended(table->fragment_table, key, orig_keyp,
|
|
&value))
|
|
value = NULL;
|
|
/* Free the key */
|
|
table->free_temporary_key_func(key);
|
|
|
|
return (fragment_head *)value;
|
|
}
|
|
|
|
/*
|
|
* Insert an fd_head into the fragment table, and return the key used.
|
|
*/
|
|
static gpointer
|
|
insert_fd_head(reassembly_table *table, fragment_head *fd_head,
|
|
const packet_info *pinfo, const guint32 id, const void *data)
|
|
{
|
|
gpointer key;
|
|
|
|
/*
|
|
* We're going to use the key to insert the fragment,
|
|
* so make a persistent version of it.
|
|
*/
|
|
key = table->persistent_key_func(pinfo, id, data);
|
|
g_hash_table_insert(table->fragment_table, key, fd_head);
|
|
return key;
|
|
}
|
|
|
|
/* This function cleans up the stored state and removes the reassembly data and
|
|
* (with one exception) all allocated memory for matching reassembly.
|
|
*
|
|
* The exception is :
|
|
* If the PDU was already completely reassembled, then the tvbuff containing the
|
|
* reassembled data WILL NOT be free()d, and the pointer to that tvbuff will be
|
|
* returned.
|
|
* Othervise the function will return NULL.
|
|
*
|
|
* So, if you call fragment_delete and it returns non-NULL, YOU are responsible
|
|
* to tvb_free() that tvbuff.
|
|
*/
|
|
tvbuff_t *
|
|
fragment_delete(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data)
|
|
{
|
|
fragment_head *fd_head;
|
|
fragment_item *fd;
|
|
tvbuff_t *fd_tvb_data=NULL;
|
|
gpointer key;
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, &key);
|
|
if(fd_head==NULL){
|
|
/* We do not recognize this as a PDU we have seen before. return */
|
|
return NULL;
|
|
}
|
|
|
|
fd_tvb_data=fd_head->tvb_data;
|
|
/* loop over all partial fragments and free any tvbuffs */
|
|
for(fd=fd_head->next;fd;){
|
|
fragment_item *tmp_fd;
|
|
tmp_fd=fd->next;
|
|
|
|
if (fd->tvb_data && !(fd->flags & FD_SUBSET_TVB))
|
|
tvb_free(fd->tvb_data);
|
|
g_slice_free(fragment_item, fd);
|
|
fd=tmp_fd;
|
|
}
|
|
g_slice_free(fragment_head, fd_head);
|
|
g_hash_table_remove(table->fragment_table, key);
|
|
|
|
return fd_tvb_data;
|
|
}
|
|
|
|
/* This function is used to check if there is partial or completed reassembly state
|
|
* matching this packet. I.e. Is there reassembly going on or not for this packet?
|
|
*/
|
|
fragment_head *
|
|
fragment_get(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data)
|
|
{
|
|
return lookup_fd_head(table, pinfo, id, data, NULL);
|
|
}
|
|
|
|
/* id *must* be the frame number for this to work! */
|
|
fragment_head *
|
|
fragment_get_reassembled(reassembly_table *table, const guint32 id)
|
|
{
|
|
fragment_head *fd_head;
|
|
reassembled_key key;
|
|
|
|
/* create key to search hash with */
|
|
key.frame = id;
|
|
key.id = id;
|
|
fd_head = (fragment_head *)g_hash_table_lookup(table->reassembled_table, &key);
|
|
|
|
return fd_head;
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_get_reassembled_id(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id)
|
|
{
|
|
fragment_head *fd_head;
|
|
reassembled_key key;
|
|
|
|
/* create key to search hash with */
|
|
key.frame = pinfo->fd->num;
|
|
key.id = id;
|
|
fd_head = (fragment_head *)g_hash_table_lookup(table->reassembled_table, &key);
|
|
|
|
return fd_head;
|
|
}
|
|
|
|
/* To specify the offset for the fragment numbering, the first fragment is added with 0, and
|
|
* afterwards this offset is set. All additional calls to off_seq_check will calculate
|
|
* the number in sequence in regards to the offset */
|
|
void
|
|
fragment_add_seq_offset(reassembly_table *table, const packet_info *pinfo, const guint32 id,
|
|
const void *data, const guint32 fragment_offset)
|
|
{
|
|
fragment_head *fd_head;
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
|
|
if (!fd_head)
|
|
return;
|
|
|
|
/* Reseting the offset is not allowed */
|
|
if ( fd_head->fragment_nr_offset != 0 )
|
|
return;
|
|
|
|
fd_head->fragment_nr_offset = fragment_offset;
|
|
}
|
|
|
|
/* This function can be used to explicitly set the total length (if known)
|
|
* for reassembly of a PDU.
|
|
* This is useful for reassembly of PDUs where one may have the total length specified
|
|
* in the first fragment instead of as for, say, IPv4 where a flag indicates which
|
|
* is the last fragment.
|
|
*
|
|
* Such protocols might fragment_add with a more_frags==TRUE for every fragment
|
|
* and just tell the reassembly engine the expected total length of the reassembled data
|
|
* using fragment_set_tot_len immediately after doing fragment_add for the first packet.
|
|
*
|
|
* 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(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data, const guint32 tot_len)
|
|
{
|
|
fragment_head *fd_head;
|
|
fragment_item *fd;
|
|
guint32 max_offset = 0;
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
|
|
if (!fd_head)
|
|
return;
|
|
|
|
/* If we're setting a block sequence number, verify that it
|
|
* doesn't conflict with values set by existing fragments.
|
|
* XXX - eliminate this check?
|
|
*/
|
|
fd = fd_head;
|
|
if (fd_head->flags & FD_BLOCKSEQUENCE) {
|
|
while (fd) {
|
|
if (fd->offset > max_offset) {
|
|
max_offset = fd->offset;
|
|
if (max_offset > tot_len) {
|
|
fd_head->error = "Bad total reassembly block count";
|
|
THROW_MESSAGE(ReassemblyError, fd_head->error);
|
|
}
|
|
}
|
|
fd = fd->next;
|
|
}
|
|
}
|
|
|
|
if (fd_head->flags & FD_DEFRAGMENTED) {
|
|
if (max_offset != tot_len) {
|
|
fd_head->error = "Defragmented complete but total length not satisfied";
|
|
THROW_MESSAGE(ReassemblyError, fd_head->error);
|
|
}
|
|
}
|
|
|
|
/* We got this far so the value is sane. */
|
|
fd_head->datalen = tot_len;
|
|
fd_head->flags |= FD_DATALEN_SET;
|
|
}
|
|
|
|
guint32
|
|
fragment_get_tot_len(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data)
|
|
{
|
|
fragment_head *fd_head;
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
|
|
|
|
if(fd_head){
|
|
return fd_head->datalen;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* This function will set the partial reassembly flag 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)
|
|
*/
|
|
|
|
void
|
|
fragment_set_partial_reassembly(reassembly_table *table,
|
|
const packet_info *pinfo, const guint32 id,
|
|
const void *data)
|
|
{
|
|
fragment_head *fd_head;
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
|
|
|
|
/*
|
|
* XXX - why not do all the stuff done early in "fragment_add_work()",
|
|
* turning off FD_DEFRAGMENTED and pointing the fragments' data
|
|
* pointers to the appropriate part of the already-reassembled
|
|
* data, and clearing the data length and "reassembled in" frame
|
|
* number, here? We currently have a hack in the TCP dissector
|
|
* not to set the "reassembled in" value if the "partial reassembly"
|
|
* flag is set, so that in the first pass through the packets
|
|
* we don't falsely set a packet as reassembled in that packet
|
|
* if the dissector decided that even more reassembly was needed.
|
|
*/
|
|
if(fd_head){
|
|
fd_head->flags |= FD_PARTIAL_REASSEMBLY;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This function gets rid of an entry from a fragment table, given
|
|
* a pointer to the key for that entry.
|
|
*
|
|
* The key freeing routine will be called by g_hash_table_remove().
|
|
*/
|
|
static void
|
|
fragment_unhash(reassembly_table *table, gpointer key)
|
|
{
|
|
/*
|
|
* Remove the entry from the fragment table.
|
|
*/
|
|
g_hash_table_remove(table->fragment_table, key);
|
|
}
|
|
|
|
/*
|
|
* This function adds fragment_head structure to a reassembled-packet
|
|
* hash table, using the frame numbers of each of the frames from
|
|
* which it was reassembled as keys, and sets the "reassembled_in"
|
|
* frame number.
|
|
*/
|
|
static void
|
|
fragment_reassembled(reassembly_table *table, fragment_head *fd_head,
|
|
const packet_info *pinfo, const guint32 id)
|
|
{
|
|
reassembled_key *new_key;
|
|
fragment_item *fd;
|
|
|
|
if (fd_head->next == NULL) {
|
|
/*
|
|
* This was not fragmented, so there's no fragment
|
|
* table; just hash it using the current frame number.
|
|
*/
|
|
new_key = g_slice_new(reassembled_key);
|
|
new_key->frame = pinfo->fd->num;
|
|
new_key->id = id;
|
|
g_hash_table_insert(table->reassembled_table, new_key, fd_head);
|
|
} else {
|
|
/*
|
|
* Hash it with the frame numbers for all the frames.
|
|
*/
|
|
for (fd = fd_head->next; fd != NULL; fd = fd->next){
|
|
new_key = g_slice_new(reassembled_key);
|
|
new_key->frame = fd->frame;
|
|
new_key->id = id;
|
|
g_hash_table_insert(table->reassembled_table, new_key,
|
|
fd_head);
|
|
}
|
|
}
|
|
fd_head->flags |= FD_DEFRAGMENTED;
|
|
fd_head->reassembled_in = pinfo->fd->num;
|
|
fd_head->reas_in_layer_num = pinfo->curr_layer_num;
|
|
}
|
|
|
|
static void
|
|
LINK_FRAG(fragment_head *fd_head,fragment_item *fd)
|
|
{
|
|
fragment_item *fd_i;
|
|
|
|
/* add fragment to list, keep list sorted */
|
|
for(fd_i= fd_head; fd_i->next;fd_i=fd_i->next) {
|
|
if (fd->offset < fd_i->next->offset )
|
|
break;
|
|
}
|
|
fd->next=fd_i->next;
|
|
fd_i->next=fd;
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* This function assumes frag_offset being a byte offset into the defragment
|
|
* packet.
|
|
*
|
|
* 01-2002
|
|
* Once the fh is defragmented (= FD_DEFRAGMENTED set), it can be
|
|
* extended using the FD_PARTIAL_REASSEMBLY flag. This flag should be set
|
|
* using fragment_set_partial_reassembly() before calling fragment_add
|
|
* with the new fragment. FD_TOOLONGFRAGMENT and FD_MULTIPLETAILS flags
|
|
* are lowered when a new extension process is started.
|
|
*/
|
|
static gboolean
|
|
fragment_add_work(fragment_head *fd_head, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 frag_offset,
|
|
const guint32 frag_data_len, const gboolean more_frags)
|
|
{
|
|
fragment_item *fd;
|
|
fragment_item *fd_i;
|
|
guint32 max, dfpos, fraglen;
|
|
tvbuff_t *old_tvb_data;
|
|
guint8 *data;
|
|
|
|
/* create new fd describing this fragment */
|
|
fd = g_slice_new(fragment_item);
|
|
fd->next = NULL;
|
|
fd->flags = 0;
|
|
fd->frame = pinfo->fd->num;
|
|
fd->offset = frag_offset;
|
|
fd->fragment_nr_offset = 0; /* will only be used with sequence */
|
|
fd->len = frag_data_len;
|
|
fd->tvb_data = NULL;
|
|
fd->error = NULL;
|
|
|
|
/*
|
|
* Are we adding to an already-completed reassembly?
|
|
*/
|
|
if (fd_head->flags & FD_DEFRAGMENTED) {
|
|
/*
|
|
* Yes. Does this fragment go past the end of the results
|
|
* of that reassembly?
|
|
* XXX - shouldn't this be ">"? If frag_offset + frag_data_len
|
|
* == fd_head->datalen, this overlaps the end of the
|
|
* reassembly, but doesn't go past it, right?
|
|
*/
|
|
if (frag_offset + frag_data_len >= fd_head->datalen) {
|
|
/*
|
|
* Yes. Have we been requested to continue reassembly?
|
|
*/
|
|
if (fd_head->flags & FD_PARTIAL_REASSEMBLY) {
|
|
/*
|
|
* Yes. Set flag in already empty fds &
|
|
* point old fds to malloc'ed data.
|
|
*/
|
|
for(fd_i=fd_head->next; fd_i; fd_i=fd_i->next){
|
|
if( !fd_i->tvb_data ) {
|
|
fd_i->tvb_data = tvb_new_subset_remaining(fd_head->tvb_data, fd_i->offset);
|
|
fd_i->flags |= FD_SUBSET_TVB;
|
|
}
|
|
fd_i->flags &= (~FD_TOOLONGFRAGMENT) & (~FD_MULTIPLETAILS);
|
|
}
|
|
fd_head->flags &= ~(FD_DEFRAGMENTED|FD_PARTIAL_REASSEMBLY|FD_DATALEN_SET);
|
|
fd_head->flags &= (~FD_TOOLONGFRAGMENT) & (~FD_MULTIPLETAILS);
|
|
fd_head->datalen=0;
|
|
fd_head->reassembled_in=0;
|
|
fd_head->reas_in_layer_num = 0;
|
|
} else {
|
|
/*
|
|
* No. Bail out since we have no idea what to
|
|
* do with this fragment (and if we keep going
|
|
* we'll run past the end of a buffer sooner
|
|
* or later).
|
|
*/
|
|
g_slice_free(fragment_item, fd);
|
|
|
|
/*
|
|
* This is an attempt to add a fragment to a
|
|
* reassembly that had already completed.
|
|
* If it had no error, we don't want to
|
|
* mark it with an error, and if it had an
|
|
* error, we don't want to overwrite it, so
|
|
* we don't set fd_head->error.
|
|
*/
|
|
if (frag_offset >= fd_head->datalen) {
|
|
/*
|
|
* The fragment starts past the end
|
|
* of the reassembled data.
|
|
*/
|
|
THROW_MESSAGE(ReassemblyError, "New fragment past old data limits");
|
|
} else {
|
|
/*
|
|
* The fragment starts before the end
|
|
* of the reassembled data, but
|
|
* runs past the end. That could
|
|
* just be a retransmission.
|
|
*/
|
|
THROW_MESSAGE(ReassemblyError, "New fragment overlaps old data (retransmission?)");
|
|
}
|
|
}
|
|
} else {
|
|
/*
|
|
* No. That means it still overlaps that, so report
|
|
* this as a problem, possibly a retransmission.
|
|
*/
|
|
g_slice_free(fragment_item, fd);
|
|
THROW_MESSAGE(ReassemblyError, "New fragment overlaps old data (retransmission?)");
|
|
}
|
|
}
|
|
|
|
/* Do this after we may have bailed out (above) so that we don't leave
|
|
* fd_head->frame in a bad state if we do */
|
|
if (fd->frame > fd_head->frame)
|
|
fd_head->frame = fd->frame;
|
|
|
|
if (!more_frags) {
|
|
/*
|
|
* This is the tail fragment in the sequence.
|
|
*/
|
|
if (fd_head->flags & FD_DATALEN_SET) {
|
|
/* ok we have already seen other tails for this packet
|
|
* it might be a duplicate.
|
|
*/
|
|
if (fd_head->datalen != (fd->offset + fd->len) ){
|
|
/* Oops, this tail indicates a different packet
|
|
* len than the previous ones. Something's wrong.
|
|
*/
|
|
fd->flags |= FD_MULTIPLETAILS;
|
|
fd_head->flags |= FD_MULTIPLETAILS;
|
|
}
|
|
} else {
|
|
/* This was the first tail fragment; now we know
|
|
* what the length of the packet should be.
|
|
*/
|
|
fd_head->datalen = fd->offset + fd->len;
|
|
fd_head->flags |= FD_DATALEN_SET;
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/* If the packet is already defragmented, this MUST be an overlap.
|
|
* The entire defragmented packet is in fd_head->data.
|
|
* Even if we have previously defragmented this packet, we still
|
|
* check it. Someone might play overlap and TTL games.
|
|
*/
|
|
if (fd_head->flags & FD_DEFRAGMENTED) {
|
|
guint32 end_offset = fd->offset + fd->len;
|
|
fd->flags |= FD_OVERLAP;
|
|
fd_head->flags |= FD_OVERLAP;
|
|
/* make sure it's not too long */
|
|
if (end_offset > fd_head->datalen || end_offset < fd->offset || end_offset < fd->len) {
|
|
fd->flags |= FD_TOOLONGFRAGMENT;
|
|
fd_head->flags |= FD_TOOLONGFRAGMENT;
|
|
}
|
|
/* make sure it doesn't conflict with previous data */
|
|
else if ( tvb_memeql(fd_head->tvb_data, fd->offset,
|
|
tvb_get_ptr(tvb,offset,fd->len),fd->len) ){
|
|
fd->flags |= FD_OVERLAPCONFLICT;
|
|
fd_head->flags |= FD_OVERLAPCONFLICT;
|
|
}
|
|
/* it was just an overlap, link it and return */
|
|
LINK_FRAG(fd_head,fd);
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
|
|
/* If we have reached this point, the packet is not defragmented yet.
|
|
* Save all payload in a buffer until we can defragment.
|
|
*/
|
|
if (!tvb_bytes_exist(tvb, offset, fd->len)) {
|
|
g_slice_free(fragment_item, fd);
|
|
THROW(BoundsError);
|
|
}
|
|
fd->tvb_data = tvb_clone_offset_len(tvb, offset, fd->len);
|
|
LINK_FRAG(fd_head,fd);
|
|
|
|
|
|
if( !(fd_head->flags & FD_DATALEN_SET) ){
|
|
/* if we don't know the datalen, there are still missing
|
|
* packets. Cheaper than the check below.
|
|
*/
|
|
return FALSE;
|
|
}
|
|
|
|
|
|
/*
|
|
* Check if we have received the entire fragment.
|
|
* This is easy since the list is sorted and the head is faked.
|
|
*
|
|
* First, we compute the amount of contiguous data that's
|
|
* available. (The check for fd_i->offset <= max rules out
|
|
* fragments that don't start before or at the end of the
|
|
* previous fragment, i.e. fragments that have a gap between
|
|
* them and the previous fragment.)
|
|
*/
|
|
max = 0;
|
|
for (fd_i=fd_head->next;fd_i;fd_i=fd_i->next) {
|
|
if ( ((fd_i->offset)<=max) &&
|
|
((fd_i->offset+fd_i->len)>max) ){
|
|
max = fd_i->offset+fd_i->len;
|
|
}
|
|
}
|
|
|
|
if (max < (fd_head->datalen)) {
|
|
/*
|
|
* The amount of contiguous data we have is less than the
|
|
* amount of data we're trying to reassemble, so we haven't
|
|
* received all packets yet.
|
|
*/
|
|
return FALSE;
|
|
}
|
|
|
|
/* we have received an entire packet, defragment it and
|
|
* free all fragments
|
|
*/
|
|
/* store old data just in case */
|
|
old_tvb_data=fd_head->tvb_data;
|
|
data = (guint8 *) g_malloc(fd_head->datalen);
|
|
fd_head->tvb_data = tvb_new_real_data(data, fd_head->datalen, fd_head->datalen);
|
|
tvb_set_free_cb(fd_head->tvb_data, g_free);
|
|
|
|
/* add all data fragments */
|
|
for (dfpos=0,fd_i=fd_head;fd_i;fd_i=fd_i->next) {
|
|
if (fd_i->len) {
|
|
/*
|
|
* The loop above that calculates max also
|
|
* ensures that the only gaps that exist here
|
|
* are ones where a fragment starts past the
|
|
* end of the reassembled datagram, and there's
|
|
* a gap between the previous fragment and
|
|
* that fragment.
|
|
*
|
|
* A "DESEGMENT_UNTIL_FIN" was involved wherein the
|
|
* FIN packet had an offset less than the highest
|
|
* fragment offset seen. [Seen from a fuzz-test:
|
|
* bug #2470]).
|
|
*
|
|
* Note that the "overlap" compare must only be
|
|
* done for fragments with (offset+len) <= fd_head->datalen
|
|
* and thus within the newly g_malloc'd buffer.
|
|
*/
|
|
if (fd_i->offset + fd_i->len > dfpos) {
|
|
if (fd_i->offset >= fd_head->datalen) {
|
|
/*
|
|
* Fragment starts after the end
|
|
* of the reassembled packet.
|
|
*
|
|
* This can happen if the length was
|
|
* set after the offending fragment
|
|
* was added to the reassembly.
|
|
*
|
|
* Flag this fragment, but don't
|
|
* try to extract any data from
|
|
* it, as there's no place to put
|
|
* it.
|
|
*
|
|
* XXX - add different flag value
|
|
* for this.
|
|
*/
|
|
fd_i->flags |= FD_TOOLONGFRAGMENT;
|
|
fd_head->flags |= FD_TOOLONGFRAGMENT;
|
|
} else if (dfpos < fd_i->offset) {
|
|
/*
|
|
* XXX - can this happen? We've
|
|
* already rejected fragments that
|
|
* start past the end of the
|
|
* reassembled datagram, and
|
|
* the loop that calculated max
|
|
* should have ruled out gaps,
|
|
* but could fd_i->offset +
|
|
* fd_i->len overflow?
|
|
*/
|
|
fd_head->error = "dfpos < offset";
|
|
} else if (dfpos - fd_i->offset > fd_i->len)
|
|
fd_head->error = "dfpos - offset > len";
|
|
else if (!fd_head->tvb_data)
|
|
fd_head->error = "no data";
|
|
else {
|
|
fraglen = fd_i->len;
|
|
if (fd_i->offset + fraglen > fd_head->datalen) {
|
|
/*
|
|
* Fragment goes past the end
|
|
* of the packet, as indicated
|
|
* by the last fragment.
|
|
*
|
|
* This can happen if the
|
|
* length was set after the
|
|
* offending fragment was
|
|
* added to the reassembly.
|
|
*
|
|
* Mark it as such, and only
|
|
* copy from it what fits in
|
|
* the packet.
|
|
*/
|
|
fd_i->flags |= FD_TOOLONGFRAGMENT;
|
|
fd_head->flags |= FD_TOOLONGFRAGMENT;
|
|
fraglen = fd_head->datalen - fd_i->offset;
|
|
}
|
|
if (fd_i->offset < dfpos) {
|
|
guint32 cmp_len = MIN(fd_i->len,(dfpos-fd_i->offset));
|
|
|
|
fd_i->flags |= FD_OVERLAP;
|
|
fd_head->flags |= FD_OVERLAP;
|
|
if ( memcmp(data + fd_i->offset,
|
|
tvb_get_ptr(fd_i->tvb_data, 0, cmp_len),
|
|
cmp_len)
|
|
) {
|
|
fd_i->flags |= FD_OVERLAPCONFLICT;
|
|
fd_head->flags |= FD_OVERLAPCONFLICT;
|
|
}
|
|
}
|
|
if (fraglen < dfpos - fd_i->offset) {
|
|
/*
|
|
* XXX - can this happen?
|
|
*/
|
|
fd_head->error = "fraglen < dfpos - offset";
|
|
} else {
|
|
memcpy(data+dfpos,
|
|
tvb_get_ptr(fd_i->tvb_data, (dfpos-fd_i->offset), fraglen-(dfpos-fd_i->offset)),
|
|
fraglen-(dfpos-fd_i->offset));
|
|
dfpos=MAX(dfpos, (fd_i->offset + fraglen));
|
|
}
|
|
}
|
|
} else {
|
|
if (fd_i->offset + fd_i->len < fd_i->offset) {
|
|
/* Integer overflow? */
|
|
fd_head->error = "offset + len < offset";
|
|
}
|
|
}
|
|
|
|
if (fd_i->flags & FD_SUBSET_TVB)
|
|
fd_i->flags &= ~FD_SUBSET_TVB;
|
|
else if (fd_i->tvb_data)
|
|
tvb_free(fd_i->tvb_data);
|
|
|
|
fd_i->tvb_data=NULL;
|
|
}
|
|
}
|
|
|
|
if (old_tvb_data)
|
|
tvb_add_to_chain(tvb, old_tvb_data);
|
|
/* mark this packet as defragmented.
|
|
allows us to skip any trailing fragments */
|
|
fd_head->flags |= FD_DEFRAGMENTED;
|
|
fd_head->reassembled_in=pinfo->fd->num;
|
|
fd_head->reas_in_layer_num = pinfo->curr_layer_num;
|
|
|
|
/* we don't throw until here to avoid leaking old_data and others */
|
|
if (fd_head->error) {
|
|
THROW_MESSAGE(ReassemblyError, fd_head->error);
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
static fragment_head *
|
|
fragment_add_common(reassembly_table *table, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 id,
|
|
const void *data, const guint32 frag_offset,
|
|
const guint32 frag_data_len, const gboolean more_frags,
|
|
const gboolean check_already_added)
|
|
{
|
|
fragment_head *fd_head;
|
|
fragment_item *fd_item;
|
|
gboolean already_added;
|
|
|
|
|
|
/* dissector shouldn't give us garbage tvb info */
|
|
DISSECTOR_ASSERT(tvb_bytes_exist(tvb, offset, frag_data_len));
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
|
|
|
|
#if 0
|
|
/* debug output of associated fragments. */
|
|
/* leave it here for future debugging sessions */
|
|
if(strcmp(pinfo->current_proto, "DCERPC") == 0) {
|
|
printf("proto:%s num:%u id:%u offset:%u len:%u more:%u visited:%u\n",
|
|
pinfo->current_proto, pinfo->fd->num, id, frag_offset, frag_data_len, more_frags, pinfo->fd->flags.visited);
|
|
if(fd_head != NULL) {
|
|
for(fd_item=fd_head->next;fd_item;fd_item=fd_item->next){
|
|
printf("fd_frame:%u fd_offset:%u len:%u datalen:%u\n",
|
|
fd_item->frame, fd_item->offset, fd_item->len, fd_item->datalen);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Is this the first pass through the capture?
|
|
*/
|
|
if (!pinfo->fd->flags.visited) {
|
|
/*
|
|
* Yes, so we could be doing reassembly. If
|
|
* "check_already_added" is true, and fd_head is non-null,
|
|
* meaning that this fragment would be added to an
|
|
* in-progress reassembly, check if we have seen this
|
|
* fragment before, i.e., if we have already added it to
|
|
* that reassembly. That can be true even on the first pass
|
|
* since we sometimes might call a subdissector multiple
|
|
* times.
|
|
*
|
|
* We check both the frame number and the fragment offset,
|
|
* so that we support multiple fragments from the same
|
|
* frame being added to the same reassembled PDU.
|
|
*/
|
|
if (check_already_added && fd_head != NULL) {
|
|
/*
|
|
* fd_head->frame is the maximum of the frame
|
|
* numbers of all the fragments added to this
|
|
* reassembly; if this frame is later than that
|
|
* frame, we know it hasn't been added yet.
|
|
*/
|
|
if (pinfo->fd->num <= fd_head->frame) {
|
|
already_added = FALSE;
|
|
/*
|
|
* The first item in the reassembly list
|
|
* is not a fragment, it's a data structure
|
|
* for the reassembled packet, so we
|
|
* start checking with the next item.
|
|
*/
|
|
for (fd_item = fd_head->next; fd_item;
|
|
fd_item = fd_item->next) {
|
|
if (pinfo->fd->num == fd_item->frame &&
|
|
frag_offset == fd_item->offset) {
|
|
already_added = TRUE;
|
|
break;
|
|
}
|
|
}
|
|
if (already_added) {
|
|
/*
|
|
* Have we already finished
|
|
* reassembling?
|
|
*/
|
|
if (fd_head->flags & FD_DEFRAGMENTED) {
|
|
/*
|
|
* Yes.
|
|
* XXX - can this ever happen?
|
|
*/
|
|
THROW_MESSAGE(ReassemblyError,
|
|
"Frame already added in first pass");
|
|
} else {
|
|
/*
|
|
* No.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
/*
|
|
* No, so we've already done all the reassembly and added
|
|
* all the fragments. Do we have a reassembly and, if so,
|
|
* have we finished reassembling?
|
|
*/
|
|
if (fd_head != NULL && fd_head->flags & FD_DEFRAGMENTED) {
|
|
/*
|
|
* Yes. This is probably being done after the
|
|
* first pass, and we've already done the work
|
|
* on the first pass.
|
|
*
|
|
* If the reassembly got a fatal error, throw that
|
|
* error again.
|
|
*/
|
|
if (fd_head->error)
|
|
THROW_MESSAGE(ReassemblyError, fd_head->error);
|
|
|
|
/*
|
|
* Is it later in the capture than all of the
|
|
* fragments in the reassembly?
|
|
*/
|
|
if (pinfo->fd->num > fd_head->frame) {
|
|
/*
|
|
* Yes, so report this as a problem,
|
|
* possibly a retransmission.
|
|
*/
|
|
THROW_MESSAGE(ReassemblyError, "New fragment overlaps old data (retransmission?)");
|
|
}
|
|
|
|
/*
|
|
* Does this fragment go past the end of the
|
|
* results of that reassembly?
|
|
*/
|
|
if (frag_offset + frag_data_len > fd_head->datalen) {
|
|
/*
|
|
* Yes.
|
|
*/
|
|
if (frag_offset >= fd_head->datalen) {
|
|
/*
|
|
* The fragment starts past the
|
|
* end of the reassembled data.
|
|
*/
|
|
THROW_MESSAGE(ReassemblyError, "New fragment past old data limits");
|
|
} else {
|
|
/*
|
|
* The fragment starts before the end
|
|
* of the reassembled data, but
|
|
* runs past the end. That could
|
|
* just be a retransmission.
|
|
*/
|
|
THROW_MESSAGE(ReassemblyError, "New fragment overlaps old data (retransmission?)");
|
|
}
|
|
}
|
|
|
|
return fd_head;
|
|
} else {
|
|
/*
|
|
* No.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
if (fd_head==NULL){
|
|
/* not found, this must be the first snooped fragment for this
|
|
* packet. Create list-head.
|
|
*/
|
|
fd_head = new_head(0);
|
|
|
|
/*
|
|
* Insert it into the hash table.
|
|
*/
|
|
insert_fd_head(table, fd_head, pinfo, id, data);
|
|
}
|
|
|
|
if (fragment_add_work(fd_head, tvb, offset, pinfo, frag_offset,
|
|
frag_data_len, more_frags)) {
|
|
/*
|
|
* Reassembly is complete.
|
|
*/
|
|
return fd_head;
|
|
} else {
|
|
/*
|
|
* Reassembly isn't complete.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_add(reassembly_table *table, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 id, const void *data,
|
|
const guint32 frag_offset, const guint32 frag_data_len,
|
|
const gboolean more_frags)
|
|
{
|
|
return fragment_add_common(table, tvb, offset, pinfo, id, data,
|
|
frag_offset, frag_data_len, more_frags, TRUE);
|
|
}
|
|
|
|
/*
|
|
* For use when you can have multiple fragments in the same frame added
|
|
* to the same reassembled PDU, e.g. with ONC RPC-over-TCP.
|
|
*/
|
|
fragment_head *
|
|
fragment_add_multiple_ok(reassembly_table *table, tvbuff_t *tvb,
|
|
const int offset, const packet_info *pinfo,
|
|
const guint32 id, const void *data,
|
|
const guint32 frag_offset,
|
|
const guint32 frag_data_len, const gboolean more_frags)
|
|
{
|
|
return fragment_add_common(table, tvb, offset, pinfo, id, data,
|
|
frag_offset, frag_data_len, more_frags, FALSE);
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_add_check(reassembly_table *table, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 id,
|
|
const void *data, const guint32 frag_offset,
|
|
const guint32 frag_data_len, const gboolean more_frags)
|
|
{
|
|
reassembled_key reass_key;
|
|
fragment_head *fd_head;
|
|
gpointer orig_key;
|
|
|
|
/*
|
|
* If this isn't the first pass, look for this frame in the table
|
|
* of reassembled packets.
|
|
*/
|
|
if (pinfo->fd->flags.visited) {
|
|
reass_key.frame = pinfo->fd->num;
|
|
reass_key.id = id;
|
|
return (fragment_head *)g_hash_table_lookup(table->reassembled_table, &reass_key);
|
|
}
|
|
|
|
/* Looks up a key in the GHashTable, returning the original key and the associated value
|
|
* and a gboolean which is TRUE if the key was found. This is useful if you need to free
|
|
* the memory allocated for the original key, for example before calling g_hash_table_remove()
|
|
*/
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, &orig_key);
|
|
if (fd_head == NULL) {
|
|
/* not found, this must be the first snooped fragment for this
|
|
* packet. Create list-head.
|
|
*/
|
|
fd_head = new_head(0);
|
|
|
|
/*
|
|
* Save the key, for unhashing it later.
|
|
*/
|
|
orig_key = insert_fd_head(table, fd_head, pinfo, id, data);
|
|
}
|
|
|
|
/*
|
|
* If this is a short frame, then we can't, and don't, do
|
|
* reassembly on it. We just give up.
|
|
*/
|
|
if (tvb_reported_length(tvb) > tvb_captured_length(tvb))
|
|
return NULL;
|
|
|
|
if (fragment_add_work(fd_head, tvb, offset, pinfo, frag_offset,
|
|
frag_data_len, more_frags)) {
|
|
/*
|
|
* Reassembly is complete.
|
|
* Remove this from the table of in-progress
|
|
* reassemblies, add it to the table of
|
|
* reassembled packets, and return it.
|
|
*/
|
|
|
|
/*
|
|
* Remove this from the table of in-progress reassemblies,
|
|
* and free up any memory used for it in that table.
|
|
*/
|
|
fragment_unhash(table, orig_key);
|
|
|
|
/*
|
|
* Add this item to the table of reassembled packets.
|
|
*/
|
|
fragment_reassembled(table, fd_head, pinfo, id);
|
|
return fd_head;
|
|
} else {
|
|
/*
|
|
* Reassembly isn't complete.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static void
|
|
fragment_defragment_and_free (fragment_head *fd_head, const packet_info *pinfo)
|
|
{
|
|
fragment_item *fd_i = NULL;
|
|
fragment_item *last_fd = NULL;
|
|
guint32 dfpos = 0, size = 0;
|
|
tvbuff_t *old_tvb_data = NULL;
|
|
guint8 *data;
|
|
|
|
for(fd_i=fd_head->next;fd_i;fd_i=fd_i->next) {
|
|
if(!last_fd || last_fd->offset!=fd_i->offset){
|
|
size+=fd_i->len;
|
|
}
|
|
last_fd=fd_i;
|
|
}
|
|
|
|
/* store old data in case the fd_i->data pointers refer to it */
|
|
old_tvb_data=fd_head->tvb_data;
|
|
data = (guint8 *) g_malloc(size);
|
|
fd_head->tvb_data = tvb_new_real_data(data, size, size);
|
|
tvb_set_free_cb(fd_head->tvb_data, g_free);
|
|
fd_head->len = size; /* record size for caller */
|
|
|
|
/* add all data fragments */
|
|
last_fd=NULL;
|
|
for (fd_i=fd_head->next; fd_i; fd_i=fd_i->next) {
|
|
if (fd_i->len) {
|
|
if(!last_fd || last_fd->offset != fd_i->offset) {
|
|
/* First fragment or in-sequence fragment */
|
|
memcpy(data+dfpos, tvb_get_ptr(fd_i->tvb_data, 0, fd_i->len), fd_i->len);
|
|
dfpos += fd_i->len;
|
|
} else {
|
|
/* duplicate/retransmission/overlap */
|
|
fd_i->flags |= FD_OVERLAP;
|
|
fd_head->flags |= FD_OVERLAP;
|
|
if(last_fd->len != fd_i->len
|
|
|| tvb_memeql(last_fd->tvb_data, 0, tvb_get_ptr(fd_i->tvb_data, 0, last_fd->len), last_fd->len) ) {
|
|
fd_i->flags |= FD_OVERLAPCONFLICT;
|
|
fd_head->flags |= FD_OVERLAPCONFLICT;
|
|
}
|
|
}
|
|
}
|
|
last_fd=fd_i;
|
|
}
|
|
|
|
/* we have defragmented the pdu, now free all fragments*/
|
|
for (fd_i=fd_head->next;fd_i;fd_i=fd_i->next) {
|
|
if (fd_i->flags & FD_SUBSET_TVB)
|
|
fd_i->flags &= ~FD_SUBSET_TVB;
|
|
else if (fd_i->tvb_data)
|
|
tvb_free(fd_i->tvb_data);
|
|
fd_i->tvb_data=NULL;
|
|
}
|
|
if (old_tvb_data)
|
|
tvb_free(old_tvb_data);
|
|
|
|
/* mark this packet as defragmented.
|
|
* allows us to skip any trailing fragments.
|
|
*/
|
|
fd_head->flags |= FD_DEFRAGMENTED;
|
|
fd_head->reassembled_in=pinfo->fd->num;
|
|
fd_head->reas_in_layer_num = pinfo->curr_layer_num;
|
|
}
|
|
|
|
/*
|
|
* This function adds a new fragment to the entry for a reassembly
|
|
* operation.
|
|
*
|
|
* The list of fragments for a specific datagram is kept sorted for
|
|
* easier handling.
|
|
*
|
|
* Returns TRUE if we have all the fragments, FALSE otherwise.
|
|
*
|
|
* This function assumes frag_number being a block sequence number.
|
|
* The bsn for the first block is 0.
|
|
*/
|
|
static gboolean
|
|
fragment_add_seq_work(fragment_head *fd_head, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 frag_number,
|
|
const guint32 frag_data_len, const gboolean more_frags)
|
|
{
|
|
fragment_item *fd;
|
|
fragment_item *fd_i;
|
|
fragment_item *last_fd;
|
|
guint32 max, dfpos;
|
|
guint32 frag_number_work;
|
|
|
|
/* Enables the use of fragment sequence numbers, which do not start with 0 */
|
|
frag_number_work = frag_number;
|
|
if ( fd_head->fragment_nr_offset != 0 )
|
|
if ( frag_number_work >= fd_head->fragment_nr_offset )
|
|
frag_number_work = frag_number - fd_head->fragment_nr_offset;
|
|
|
|
/* if the partial reassembly flag has been set, and we are extending
|
|
* the pdu, un-reassemble the pdu. This means pointing old fds to malloc'ed data.
|
|
*/
|
|
if(fd_head->flags & FD_DEFRAGMENTED && frag_number_work >= fd_head->datalen &&
|
|
fd_head->flags & FD_PARTIAL_REASSEMBLY){
|
|
guint32 lastdfpos = 0;
|
|
dfpos = 0;
|
|
for(fd_i=fd_head->next; fd_i; fd_i=fd_i->next){
|
|
if( !fd_i->tvb_data ) {
|
|
if( fd_i->flags & FD_OVERLAP ) {
|
|
/* this is a duplicate of the previous
|
|
* fragment. */
|
|
fd_i->tvb_data = tvb_new_subset_remaining(fd_head->tvb_data, lastdfpos);
|
|
} else {
|
|
fd_i->tvb_data = tvb_new_subset_remaining(fd_head->tvb_data, dfpos);
|
|
lastdfpos = dfpos;
|
|
dfpos += fd_i->len;
|
|
}
|
|
fd_i->flags |= FD_SUBSET_TVB;
|
|
}
|
|
fd_i->flags &= (~FD_TOOLONGFRAGMENT) & (~FD_MULTIPLETAILS);
|
|
}
|
|
fd_head->flags &= ~(FD_DEFRAGMENTED|FD_PARTIAL_REASSEMBLY|FD_DATALEN_SET);
|
|
fd_head->flags &= (~FD_TOOLONGFRAGMENT) & (~FD_MULTIPLETAILS);
|
|
fd_head->datalen=0;
|
|
fd_head->reassembled_in=0;
|
|
fd_head->reas_in_layer_num = 0;
|
|
}
|
|
|
|
|
|
/* create new fd describing this fragment */
|
|
fd = g_slice_new(fragment_item);
|
|
fd->next = NULL;
|
|
fd->flags = 0;
|
|
fd->frame = pinfo->fd->num;
|
|
fd->offset = frag_number_work;
|
|
fd->len = frag_data_len;
|
|
fd->tvb_data = NULL;
|
|
fd->error = NULL;
|
|
|
|
if (!more_frags) {
|
|
/*
|
|
* This is the tail fragment in the sequence.
|
|
*/
|
|
if (fd_head->flags&FD_DATALEN_SET) {
|
|
/* ok we have already seen other tails for this packet
|
|
* it might be a duplicate.
|
|
*/
|
|
if (fd_head->datalen != fd->offset ){
|
|
/* Oops, this tail indicates a different packet
|
|
* len than the previous ones. Something's wrong.
|
|
*/
|
|
fd->flags |= FD_MULTIPLETAILS;
|
|
fd_head->flags |= FD_MULTIPLETAILS;
|
|
}
|
|
} else {
|
|
/* this was the first tail fragment, now we know the
|
|
* sequence number of that fragment (which is NOT
|
|
* the length of the packet!)
|
|
*/
|
|
fd_head->datalen = fd->offset;
|
|
fd_head->flags |= FD_DATALEN_SET;
|
|
}
|
|
}
|
|
|
|
/* If the packet is already defragmented, this MUST be an overlap.
|
|
* The entire defragmented packet is in fd_head->data
|
|
* Even if we have previously defragmented this packet, we still check
|
|
* check it. Someone might play overlap and TTL games.
|
|
*/
|
|
if (fd_head->flags & FD_DEFRAGMENTED) {
|
|
fd->flags |= FD_OVERLAP;
|
|
fd_head->flags |= FD_OVERLAP;
|
|
|
|
/* make sure it's not past the end */
|
|
if (fd->offset > fd_head->datalen) {
|
|
/* new fragment comes after the end */
|
|
fd->flags |= FD_TOOLONGFRAGMENT;
|
|
fd_head->flags |= FD_TOOLONGFRAGMENT;
|
|
LINK_FRAG(fd_head,fd);
|
|
return TRUE;
|
|
}
|
|
/* make sure it doesn't conflict with previous data */
|
|
dfpos=0;
|
|
last_fd=NULL;
|
|
for (fd_i=fd_head->next;fd_i && (fd_i->offset!=fd->offset);fd_i=fd_i->next) {
|
|
if (!last_fd || last_fd->offset!=fd_i->offset){
|
|
dfpos += fd_i->len;
|
|
}
|
|
last_fd=fd_i;
|
|
}
|
|
if(fd_i){
|
|
/* new fragment overlaps existing fragment */
|
|
if(fd_i->len!=fd->len){
|
|
/*
|
|
* They have different lengths; this
|
|
* is definitely a conflict.
|
|
*/
|
|
fd->flags |= FD_OVERLAPCONFLICT;
|
|
fd_head->flags |= FD_OVERLAPCONFLICT;
|
|
LINK_FRAG(fd_head,fd);
|
|
return TRUE;
|
|
}
|
|
DISSECTOR_ASSERT(fd_head->len >= dfpos + fd->len);
|
|
if (tvb_memeql(fd_head->tvb_data, dfpos,
|
|
tvb_get_ptr(tvb,offset,fd->len),fd->len) ){
|
|
/*
|
|
* They have the same length, but the
|
|
* data isn't the same.
|
|
*/
|
|
fd->flags |= FD_OVERLAPCONFLICT;
|
|
fd_head->flags |= FD_OVERLAPCONFLICT;
|
|
LINK_FRAG(fd_head,fd);
|
|
return TRUE;
|
|
}
|
|
/* it was just an overlap, link it and return */
|
|
LINK_FRAG(fd_head,fd);
|
|
return TRUE;
|
|
} else {
|
|
/*
|
|
* New fragment doesn't overlap an existing
|
|
* fragment - there was presumably a gap in
|
|
* the sequence number space.
|
|
*
|
|
* XXX - what should we do here? Is it always
|
|
* the case that there are no gaps, or are there
|
|
* protcols using sequence numbers where there
|
|
* can be gaps?
|
|
*
|
|
* If the former, the check below for having
|
|
* received all the fragments should check for
|
|
* holes in the sequence number space and for the
|
|
* first sequence number being 0. If we do that,
|
|
* the only way we can get here is if this fragment
|
|
* is past the end of the sequence number space -
|
|
* but the check for "fd->offset > fd_head->datalen"
|
|
* would have caught that above, so it can't happen.
|
|
*
|
|
* If the latter, we don't have a good way of
|
|
* knowing whether reassembly is complete if we
|
|
* get packet out of order such that the "last"
|
|
* fragment doesn't show up last - but, unless
|
|
* in-order reliable delivery of fragments is
|
|
* guaranteed, an implementation of the protocol
|
|
* has no way of knowing whether reassembly is
|
|
* complete, either.
|
|
*
|
|
* For now, we just link the fragment in and
|
|
* return.
|
|
*/
|
|
LINK_FRAG(fd_head,fd);
|
|
return TRUE;
|
|
}
|
|
}
|
|
|
|
/* If we have reached this point, the packet is not defragmented yet.
|
|
* Save all payload in a buffer until we can defragment.
|
|
*/
|
|
/* check len, there may be a fragment with 0 len, that is actually the tail */
|
|
if (fd->len) {
|
|
if (!tvb_bytes_exist(tvb, offset, fd->len)) {
|
|
/* abort if we didn't capture the entire fragment due
|
|
* to a too-short snapshot length */
|
|
g_slice_free(fragment_item, fd);
|
|
return FALSE;
|
|
}
|
|
|
|
fd->tvb_data = tvb_clone_offset_len(tvb, offset, fd->len);
|
|
}
|
|
LINK_FRAG(fd_head,fd);
|
|
|
|
|
|
if( !(fd_head->flags & FD_DATALEN_SET) ){
|
|
/* if we don't know the sequence number of the last fragment,
|
|
* there are definitely still missing packets. Cheaper than
|
|
* the check below.
|
|
*/
|
|
return FALSE;
|
|
}
|
|
|
|
|
|
/* check if we have received the entire fragment
|
|
* this is easy since the list is sorted and the head is faked.
|
|
* common case the whole list is scanned.
|
|
*/
|
|
max = 0;
|
|
for(fd_i=fd_head->next;fd_i;fd_i=fd_i->next) {
|
|
if ( fd_i->offset==max ){
|
|
max++;
|
|
}
|
|
}
|
|
/* max will now be datalen+1 if all fragments have been seen */
|
|
|
|
if (max <= fd_head->datalen) {
|
|
/* we have not received all packets yet */
|
|
return FALSE;
|
|
}
|
|
|
|
|
|
if (max > (fd_head->datalen+1)) {
|
|
/* oops, too long fragment detected */
|
|
fd->flags |= FD_TOOLONGFRAGMENT;
|
|
fd_head->flags |= FD_TOOLONGFRAGMENT;
|
|
}
|
|
|
|
|
|
/* we have received an entire packet, defragment it and
|
|
* free all fragments
|
|
*/
|
|
fragment_defragment_and_free(fd_head, pinfo);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* Returns a pointer to the head of the fragment data list if we have all the
|
|
* fragments, NULL otherwise.
|
|
*
|
|
* This function assumes frag_number being a block sequence number.
|
|
* The bsn for the first block is 0.
|
|
*/
|
|
static fragment_head *
|
|
fragment_add_seq_common(reassembly_table *table, tvbuff_t *tvb,
|
|
const int offset, const packet_info *pinfo,
|
|
const guint32 id, const void *data,
|
|
guint32 frag_number, const guint32 frag_data_len,
|
|
const gboolean more_frags, const guint32 flags,
|
|
gpointer *orig_keyp)
|
|
{
|
|
fragment_head *fd_head;
|
|
gpointer orig_key;
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, &orig_key);
|
|
|
|
/* have we already seen this frame ?*/
|
|
if (pinfo->fd->flags.visited) {
|
|
if (fd_head != NULL && fd_head->flags & FD_DEFRAGMENTED) {
|
|
if (orig_keyp != NULL)
|
|
*orig_keyp = orig_key;
|
|
return fd_head;
|
|
} else {
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
if (fd_head==NULL){
|
|
/* not found, this must be the first snooped fragment for this
|
|
* packet. Create list-head.
|
|
*/
|
|
fd_head= new_head(FD_BLOCKSEQUENCE);
|
|
|
|
if((flags & (REASSEMBLE_FLAGS_NO_FRAG_NUMBER|REASSEMBLE_FLAGS_802_11_HACK))
|
|
&& !more_frags) {
|
|
/*
|
|
* This is the last fragment for this packet, and
|
|
* is the only one we've seen.
|
|
*
|
|
* Either we don't have sequence numbers, in which
|
|
* case we assume this is the first fragment for
|
|
* this packet, or we're doing special 802.11
|
|
* processing, in which case we assume it's one
|
|
* of those reassembled packets with a non-zero
|
|
* fragment number (see packet-80211.c); just
|
|
* return a pointer to the head of the list;
|
|
* fragment_add_seq_check will then add it to the table
|
|
* of reassembled packets.
|
|
*/
|
|
if (orig_keyp != NULL)
|
|
*orig_keyp = NULL;
|
|
fd_head->reassembled_in=pinfo->fd->num;
|
|
fd_head->reas_in_layer_num = pinfo->curr_layer_num;
|
|
return fd_head;
|
|
}
|
|
|
|
orig_key = insert_fd_head(table, fd_head, pinfo, id, data);
|
|
if (orig_keyp != NULL)
|
|
*orig_keyp = orig_key;
|
|
|
|
/*
|
|
* If we weren't given an initial fragment number,
|
|
* make it 0.
|
|
*/
|
|
if (flags & REASSEMBLE_FLAGS_NO_FRAG_NUMBER)
|
|
frag_number = 0;
|
|
} else {
|
|
if (orig_keyp != NULL)
|
|
*orig_keyp = orig_key;
|
|
|
|
if (flags & REASSEMBLE_FLAGS_NO_FRAG_NUMBER) {
|
|
fragment_item *fd;
|
|
/*
|
|
* If we weren't given an initial fragment number,
|
|
* use the next expected fragment number as the fragment
|
|
* number for this fragment.
|
|
*/
|
|
for (fd = fd_head; fd != NULL; fd = fd->next) {
|
|
if (fd->next == NULL)
|
|
frag_number = fd->offset + 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* XXX I've copied this over from the old separate
|
|
* fragment_add_seq_check_work, but I'm not convinced it's doing the
|
|
* right thing -- rav
|
|
*
|
|
* If we don't have all the data that is in this fragment,
|
|
* then we can't, and don't, do reassembly on it.
|
|
*
|
|
* If it's the first frame, handle it as an unfragmented packet.
|
|
* Otherwise, just handle it as a fragment.
|
|
*
|
|
* If "more_frags" isn't set, we get rid of the entry in the
|
|
* hash table for this reassembly, as we don't need it any more.
|
|
*/
|
|
if ((flags & REASSEMBLE_FLAGS_CHECK_DATA_PRESENT) &&
|
|
!tvb_bytes_exist(tvb, offset, frag_data_len)) {
|
|
fd_head -> flags |= FD_DATA_NOT_PRESENT;
|
|
if (frag_number == 0) {
|
|
return fd_head;
|
|
}
|
|
else {
|
|
if (!more_frags) {
|
|
/*
|
|
* Remove this from the table of in-progress
|
|
* reassemblies, and free up any memory used for
|
|
* it in that table.
|
|
*/
|
|
fragment_unhash(table, *orig_keyp);
|
|
free_all_fragments(NULL, fd_head, NULL);
|
|
}
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
if (fragment_add_seq_work(fd_head, tvb, offset, pinfo,
|
|
frag_number, frag_data_len, more_frags)) {
|
|
/*
|
|
* Reassembly is complete.
|
|
*/
|
|
return fd_head;
|
|
} else {
|
|
/*
|
|
* Reassembly isn't complete.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_add_seq(reassembly_table *table, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 id, const void *data,
|
|
const guint32 frag_number, const guint32 frag_data_len,
|
|
const gboolean more_frags, const guint32 flags)
|
|
{
|
|
return fragment_add_seq_common(table, tvb, offset, pinfo, id, data,
|
|
frag_number, frag_data_len,
|
|
more_frags, flags, NULL);
|
|
}
|
|
|
|
/*
|
|
* This does the work for "fragment_add_seq_check()" and
|
|
* "fragment_add_seq_next()".
|
|
*
|
|
* This function assumes frag_number being a block sequence number.
|
|
* The bsn for the first block is 0.
|
|
*
|
|
* If "no_frag_number" is TRUE, it uses the next expected fragment number
|
|
* as the fragment number if there is a reassembly in progress, otherwise
|
|
* it uses 0.
|
|
*
|
|
* If "no_frag_number" is FALSE, it uses the "frag_number" argument as
|
|
* the fragment number.
|
|
*
|
|
* If this is the first fragment seen for this datagram, a new
|
|
* "fragment_head" structure is allocated to refer to the reassembled
|
|
* packet.
|
|
*
|
|
* This fragment is added to the linked list of fragments for this packet.
|
|
*
|
|
* If "more_frags" is false and REASSEMBLE_FLAGS_802_11_HACK (as the name
|
|
* implies, a special hack for 802.11) or REASSEMBLE_FLAGS_NO_FRAG_NUMBER
|
|
* (implying messages must be in order since there's no sequence number) are
|
|
* set in "flags", then this (one element) list is returned.
|
|
*
|
|
* If, after processing this fragment, we have all the fragments,
|
|
* "fragment_add_seq_check_work()" removes that from the fragment hash
|
|
* table if necessary and adds it to the table of reassembled fragments,
|
|
* and returns a pointer to the head of the fragment list.
|
|
*
|
|
* Otherwise, it returns NULL.
|
|
*
|
|
* XXX - Should we simply return NULL for zero-length fragments?
|
|
*/
|
|
static fragment_head *
|
|
fragment_add_seq_check_work(reassembly_table *table, tvbuff_t *tvb,
|
|
const int offset, const packet_info *pinfo,
|
|
const guint32 id, const void *data,
|
|
const guint32 frag_number,
|
|
const guint32 frag_data_len,
|
|
const gboolean more_frags, const guint32 flags)
|
|
{
|
|
reassembled_key reass_key;
|
|
fragment_head *fd_head;
|
|
gpointer orig_key;
|
|
|
|
/*
|
|
* Have we already seen this frame?
|
|
* If so, look for it in the table of reassembled packets.
|
|
*/
|
|
if (pinfo->fd->flags.visited) {
|
|
reass_key.frame = pinfo->fd->num;
|
|
reass_key.id = id;
|
|
return (fragment_head *)g_hash_table_lookup(table->reassembled_table, &reass_key);
|
|
}
|
|
|
|
fd_head = fragment_add_seq_common(table, tvb, offset, pinfo, id, data,
|
|
frag_number, frag_data_len,
|
|
more_frags,
|
|
flags|REASSEMBLE_FLAGS_CHECK_DATA_PRESENT,
|
|
&orig_key);
|
|
if (fd_head) {
|
|
if(fd_head->flags & FD_DATA_NOT_PRESENT) {
|
|
/* this is the first fragment of a datagram with
|
|
* truncated fragments. Don't move it to the
|
|
* reassembled table. */
|
|
return fd_head;
|
|
}
|
|
|
|
/*
|
|
* Reassembly is complete.
|
|
*
|
|
* If this is in the table of in-progress reassemblies,
|
|
* remove it from that table. (It could be that this
|
|
* was the first and last fragment, so that no
|
|
* reassembly was done.)
|
|
*/
|
|
if (orig_key != NULL)
|
|
fragment_unhash(table, orig_key);
|
|
|
|
/*
|
|
* Add this item to the table of reassembled packets.
|
|
*/
|
|
fragment_reassembled(table, fd_head, pinfo, id);
|
|
return fd_head;
|
|
} else {
|
|
/*
|
|
* Reassembly isn't complete.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_add_seq_check(reassembly_table *table, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 id,
|
|
const void *data,
|
|
const guint32 frag_number, const guint32 frag_data_len,
|
|
const gboolean more_frags)
|
|
{
|
|
return fragment_add_seq_check_work(table, tvb, offset, pinfo, id, data,
|
|
frag_number, frag_data_len,
|
|
more_frags, 0);
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_add_seq_802_11(reassembly_table *table, tvbuff_t *tvb,
|
|
const int offset, const packet_info *pinfo,
|
|
const guint32 id, const void *data,
|
|
const guint32 frag_number, const guint32 frag_data_len,
|
|
const gboolean more_frags)
|
|
{
|
|
return fragment_add_seq_check_work(table, tvb, offset, pinfo, id, data,
|
|
frag_number, frag_data_len,
|
|
more_frags,
|
|
REASSEMBLE_FLAGS_802_11_HACK);
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_add_seq_next(reassembly_table *table, tvbuff_t *tvb, const int offset,
|
|
const packet_info *pinfo, const guint32 id,
|
|
const void *data, const guint32 frag_data_len,
|
|
const gboolean more_frags)
|
|
{
|
|
return fragment_add_seq_check_work(table, tvb, offset, pinfo, id, data,
|
|
0, frag_data_len, more_frags,
|
|
REASSEMBLE_FLAGS_NO_FRAG_NUMBER);
|
|
}
|
|
|
|
void
|
|
fragment_start_seq_check(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data,
|
|
const guint32 tot_len)
|
|
{
|
|
fragment_head *fd_head;
|
|
|
|
/* Have we already seen this frame ?*/
|
|
if (pinfo->fd->flags.visited) {
|
|
return;
|
|
}
|
|
|
|
/* Check if fragment data exists */
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
|
|
|
|
if (fd_head == NULL) {
|
|
/* Create list-head. */
|
|
fd_head = g_slice_new(fragment_head);
|
|
fd_head->next = NULL;
|
|
fd_head->datalen = tot_len;
|
|
fd_head->offset = 0;
|
|
fd_head->fragment_nr_offset = 0;
|
|
fd_head->len = 0;
|
|
fd_head->flags = FD_BLOCKSEQUENCE|FD_DATALEN_SET;
|
|
fd_head->tvb_data = NULL;
|
|
fd_head->reassembled_in = 0;
|
|
fd_head->reas_in_layer_num = 0;
|
|
fd_head->error = NULL;
|
|
|
|
insert_fd_head(table, fd_head, pinfo, id, data);
|
|
}
|
|
}
|
|
|
|
fragment_head *
|
|
fragment_end_seq_next(reassembly_table *table, const packet_info *pinfo,
|
|
const guint32 id, const void *data)
|
|
{
|
|
reassembled_key reass_key;
|
|
reassembled_key *new_key;
|
|
fragment_head *fd_head;
|
|
gpointer orig_key;
|
|
|
|
/*
|
|
* Have we already seen this frame?
|
|
* If so, look for it in the table of reassembled packets.
|
|
*/
|
|
if (pinfo->fd->flags.visited) {
|
|
reass_key.frame = pinfo->fd->num;
|
|
reass_key.id = id;
|
|
return (fragment_head *)g_hash_table_lookup(table->reassembled_table, &reass_key);
|
|
}
|
|
|
|
fd_head = lookup_fd_head(table, pinfo, id, data, &orig_key);
|
|
|
|
if (fd_head) {
|
|
if (fd_head->flags & FD_DATA_NOT_PRESENT) {
|
|
/* No data added */
|
|
return NULL;
|
|
}
|
|
|
|
fd_head->datalen = fd_head->offset;
|
|
fd_head->flags |= FD_DATALEN_SET;
|
|
|
|
fragment_defragment_and_free (fd_head, pinfo);
|
|
|
|
/*
|
|
* Remove this from the table of in-progress reassemblies,
|
|
* and free up any memory used for it in that table.
|
|
*/
|
|
fragment_unhash(table, orig_key);
|
|
|
|
/*
|
|
* Add this item to the table of reassembled packets.
|
|
*/
|
|
fragment_reassembled(table, fd_head, pinfo, id);
|
|
if (fd_head->next != NULL) {
|
|
new_key = g_slice_new(reassembled_key);
|
|
new_key->frame = pinfo->fd->num;
|
|
new_key->id = id;
|
|
g_hash_table_insert(table->reassembled_table, new_key, fd_head);
|
|
}
|
|
|
|
return fd_head;
|
|
} else {
|
|
/*
|
|
* Fragment data not found.
|
|
*/
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Process reassembled data; if we're on the frame in which the data
|
|
* was reassembled, 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.
|
|
*/
|
|
tvbuff_t *
|
|
process_reassembled_data(tvbuff_t *tvb, const int offset, packet_info *pinfo,
|
|
const char *name, fragment_head *fd_head, const fragment_items *fit,
|
|
gboolean *update_col_infop, proto_tree *tree)
|
|
{
|
|
tvbuff_t *next_tvb;
|
|
gboolean update_col_info;
|
|
proto_item *frag_tree_item;
|
|
|
|
if (fd_head != NULL && pinfo->fd->num == fd_head->reassembled_in && pinfo->curr_layer_num == fd_head->reas_in_layer_num) {
|
|
/*
|
|
* OK, we've reassembled this.
|
|
* Is this something that's been reassembled from more
|
|
* than one fragment?
|
|
*/
|
|
if (fd_head->next != NULL) {
|
|
/*
|
|
* Yes.
|
|
* Allocate a new tvbuff, referring to the
|
|
* reassembled payload, and set
|
|
* the tvbuff to the list of tvbuffs to which
|
|
* the tvbuff we were handed refers, so it'll get
|
|
* cleaned up when that tvbuff is cleaned up.
|
|
*/
|
|
next_tvb = tvb_new_chain(tvb, fd_head->tvb_data);
|
|
|
|
/* Add the defragmented data to the data source list. */
|
|
add_new_data_source(pinfo, next_tvb, name);
|
|
|
|
/* show all fragments */
|
|
if (fd_head->flags & FD_BLOCKSEQUENCE) {
|
|
update_col_info = !show_fragment_seq_tree(
|
|
fd_head, fit, tree, pinfo, next_tvb, &frag_tree_item);
|
|
} else {
|
|
update_col_info = !show_fragment_tree(fd_head,
|
|
fit, tree, pinfo, next_tvb, &frag_tree_item);
|
|
}
|
|
} else {
|
|
/*
|
|
* No.
|
|
* Return a tvbuff with the payload.
|
|
*/
|
|
next_tvb = tvb_new_subset_remaining(tvb, offset);
|
|
pinfo->fragmented = FALSE; /* one-fragment packet */
|
|
update_col_info = TRUE;
|
|
}
|
|
if (update_col_infop != NULL)
|
|
*update_col_infop = update_col_info;
|
|
} else {
|
|
/*
|
|
* We don't have the complete reassembled payload, or this
|
|
* isn't the final frame of that payload.
|
|
*/
|
|
next_tvb = NULL;
|
|
|
|
/*
|
|
* If we know what frame this was reassembled in,
|
|
* and if there's a field to use for the number of
|
|
* the frame in which the packet was reassembled,
|
|
* add it to the protocol tree.
|
|
*/
|
|
if (fd_head != NULL && fit->hf_reassembled_in != NULL) {
|
|
proto_tree_add_uint(tree,
|
|
*(fit->hf_reassembled_in), tvb,
|
|
0, 0, fd_head->reassembled_in);
|
|
}
|
|
}
|
|
return next_tvb;
|
|
}
|
|
|
|
/*
|
|
* Show a single fragment in a fragment subtree, and put information about
|
|
* it in the top-level item for that subtree.
|
|
*/
|
|
static void
|
|
show_fragment(fragment_item *fd, const int offset, const fragment_items *fit,
|
|
proto_tree *ft, proto_item *fi, const gboolean first_frag,
|
|
const guint32 count, tvbuff_t *tvb, packet_info *pinfo)
|
|
{
|
|
proto_item *fei=NULL;
|
|
int hf;
|
|
|
|
if (first_frag) {
|
|
gchar *name;
|
|
if (count == 1) {
|
|
name = g_strdup(proto_registrar_get_name(*(fit->hf_fragment)));
|
|
} else {
|
|
name = g_strdup(proto_registrar_get_name(*(fit->hf_fragments)));
|
|
}
|
|
proto_item_set_text(fi, "%u %s (%u byte%s): ", count, name, tvb_captured_length(tvb),
|
|
plurality(tvb_captured_length(tvb), "", "s"));
|
|
g_free(name);
|
|
} else {
|
|
proto_item_append_text(fi, ", ");
|
|
}
|
|
proto_item_append_text(fi, "#%u(%u)", fd->frame, fd->len);
|
|
|
|
if (fd->flags & (FD_OVERLAPCONFLICT
|
|
|FD_MULTIPLETAILS|FD_TOOLONGFRAGMENT) ) {
|
|
hf = *(fit->hf_fragment_error);
|
|
} else {
|
|
hf = *(fit->hf_fragment);
|
|
}
|
|
if (fd->len == 0) {
|
|
fei = proto_tree_add_uint_format(ft, hf,
|
|
tvb, offset, fd->len,
|
|
fd->frame,
|
|
"Frame: %u (no data)",
|
|
fd->frame);
|
|
} else {
|
|
fei = proto_tree_add_uint_format(ft, hf,
|
|
tvb, offset, fd->len,
|
|
fd->frame,
|
|
"Frame: %u, payload: %u-%u (%u byte%s)",
|
|
fd->frame,
|
|
offset,
|
|
offset+fd->len-1,
|
|
fd->len,
|
|
plurality(fd->len, "", "s"));
|
|
}
|
|
PROTO_ITEM_SET_GENERATED(fei);
|
|
mark_frame_as_depended_upon(pinfo, fd->frame);
|
|
if (fd->flags & (FD_OVERLAP|FD_OVERLAPCONFLICT
|
|
|FD_MULTIPLETAILS|FD_TOOLONGFRAGMENT) ) {
|
|
/* this fragment has some flags set, create a subtree
|
|
* for it and display the flags.
|
|
*/
|
|
proto_tree *fet=NULL;
|
|
|
|
fet = proto_item_add_subtree(fei, *(fit->ett_fragment));
|
|
if (fd->flags&FD_OVERLAP) {
|
|
fei=proto_tree_add_boolean(fet,
|
|
*(fit->hf_fragment_overlap),
|
|
tvb, 0, 0,
|
|
TRUE);
|
|
PROTO_ITEM_SET_GENERATED(fei);
|
|
}
|
|
if (fd->flags&FD_OVERLAPCONFLICT) {
|
|
fei=proto_tree_add_boolean(fet,
|
|
*(fit->hf_fragment_overlap_conflict),
|
|
tvb, 0, 0,
|
|
TRUE);
|
|
PROTO_ITEM_SET_GENERATED(fei);
|
|
}
|
|
if (fd->flags&FD_MULTIPLETAILS) {
|
|
fei=proto_tree_add_boolean(fet,
|
|
*(fit->hf_fragment_multiple_tails),
|
|
tvb, 0, 0,
|
|
TRUE);
|
|
PROTO_ITEM_SET_GENERATED(fei);
|
|
}
|
|
if (fd->flags&FD_TOOLONGFRAGMENT) {
|
|
fei=proto_tree_add_boolean(fet,
|
|
*(fit->hf_fragment_too_long_fragment),
|
|
tvb, 0, 0,
|
|
TRUE);
|
|
PROTO_ITEM_SET_GENERATED(fei);
|
|
}
|
|
}
|
|
}
|
|
|
|
static gboolean
|
|
show_fragment_errs_in_col(fragment_head *fd_head, const fragment_items *fit,
|
|
packet_info *pinfo)
|
|
{
|
|
if (fd_head->flags & (FD_OVERLAPCONFLICT
|
|
|FD_MULTIPLETAILS|FD_TOOLONGFRAGMENT) ) {
|
|
col_add_fstr(pinfo->cinfo, COL_INFO, "[Illegal %s]", fit->tag);
|
|
return TRUE;
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
/* This function will build the fragment subtree; it's for fragments
|
|
reassembled with "fragment_add()".
|
|
|
|
It will return TRUE if there were fragmentation errors
|
|
or FALSE if fragmentation was ok.
|
|
*/
|
|
gboolean
|
|
show_fragment_tree(fragment_head *fd_head, const fragment_items *fit,
|
|
proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, proto_item **fi)
|
|
{
|
|
fragment_item *fd;
|
|
proto_tree *ft;
|
|
gboolean first_frag;
|
|
guint32 count = 0;
|
|
/* It's not fragmented. */
|
|
pinfo->fragmented = FALSE;
|
|
|
|
*fi = proto_tree_add_item(tree, *(fit->hf_fragments), tvb, 0, -1, ENC_NA);
|
|
PROTO_ITEM_SET_GENERATED(*fi);
|
|
|
|
ft = proto_item_add_subtree(*fi, *(fit->ett_fragments));
|
|
first_frag = TRUE;
|
|
for (fd = fd_head->next; fd != NULL; fd = fd->next) {
|
|
count++;
|
|
}
|
|
for (fd = fd_head->next; fd != NULL; fd = fd->next) {
|
|
show_fragment(fd, fd->offset, fit, ft, *fi, first_frag, count, tvb, pinfo);
|
|
first_frag = FALSE;
|
|
}
|
|
|
|
if (fit->hf_fragment_count) {
|
|
proto_item *fli = proto_tree_add_uint(ft, *(fit->hf_fragment_count),
|
|
tvb, 0, 0, count);
|
|
PROTO_ITEM_SET_GENERATED(fli);
|
|
}
|
|
|
|
if (fit->hf_reassembled_length) {
|
|
proto_item *fli = proto_tree_add_uint(ft, *(fit->hf_reassembled_length),
|
|
tvb, 0, 0, tvb_captured_length (tvb));
|
|
PROTO_ITEM_SET_GENERATED(fli);
|
|
}
|
|
|
|
if (fit->hf_reassembled_data) {
|
|
proto_item *fli = proto_tree_add_item(ft, *(fit->hf_reassembled_data),
|
|
tvb, 0, tvb_captured_length(tvb), ENC_NA);
|
|
PROTO_ITEM_SET_GENERATED(fli);
|
|
}
|
|
|
|
return show_fragment_errs_in_col(fd_head, fit, pinfo);
|
|
}
|
|
|
|
/* This function will build the fragment subtree; it's for fragments
|
|
reassembled with "fragment_add_seq()" or "fragment_add_seq_check()".
|
|
|
|
It will return TRUE if there were fragmentation errors
|
|
or FALSE if fragmentation was ok.
|
|
*/
|
|
gboolean
|
|
show_fragment_seq_tree(fragment_head *fd_head, const fragment_items *fit,
|
|
proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, proto_item **fi)
|
|
{
|
|
guint32 offset, next_offset, count = 0;
|
|
fragment_item *fd, *last_fd;
|
|
proto_tree *ft;
|
|
gboolean first_frag;
|
|
|
|
/* It's not fragmented. */
|
|
pinfo->fragmented = FALSE;
|
|
|
|
*fi = proto_tree_add_item(tree, *(fit->hf_fragments), tvb, 0, -1, ENC_NA);
|
|
PROTO_ITEM_SET_GENERATED(*fi);
|
|
|
|
ft = proto_item_add_subtree(*fi, *(fit->ett_fragments));
|
|
offset = 0;
|
|
next_offset = 0;
|
|
last_fd = NULL;
|
|
first_frag = TRUE;
|
|
for (fd = fd_head->next; fd != NULL; fd = fd->next){
|
|
count++;
|
|
}
|
|
for (fd = fd_head->next; fd != NULL; fd = fd->next){
|
|
if (last_fd == NULL || last_fd->offset != fd->offset) {
|
|
offset = next_offset;
|
|
next_offset += fd->len;
|
|
}
|
|
last_fd = fd;
|
|
show_fragment(fd, offset, fit, ft, *fi, first_frag, count, tvb, pinfo);
|
|
first_frag = FALSE;
|
|
}
|
|
|
|
if (fit->hf_fragment_count) {
|
|
proto_item *fli = proto_tree_add_uint(ft, *(fit->hf_fragment_count),
|
|
tvb, 0, 0, count);
|
|
PROTO_ITEM_SET_GENERATED(fli);
|
|
}
|
|
|
|
if (fit->hf_reassembled_length) {
|
|
proto_item *fli = proto_tree_add_uint(ft, *(fit->hf_reassembled_length),
|
|
tvb, 0, 0, tvb_captured_length (tvb));
|
|
PROTO_ITEM_SET_GENERATED(fli);
|
|
}
|
|
|
|
if (fit->hf_reassembled_data) {
|
|
proto_item *fli = proto_tree_add_item(ft, *(fit->hf_reassembled_data),
|
|
tvb, 0, tvb_captured_length(tvb), ENC_NA);
|
|
PROTO_ITEM_SET_GENERATED(fli);
|
|
}
|
|
|
|
return show_fragment_errs_in_col(fd_head, fit, pinfo);
|
|
}
|
|
|
|
/*
|
|
* Editor modelines - http://www.wireshark.org/tools/modelines.html
|
|
*
|
|
* Local variables:
|
|
* c-basic-offset: 8
|
|
* tab-width: 8
|
|
* indent-tabs-mode: t
|
|
* End:
|
|
*
|
|
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
|
|
* :indentSize=8:tabSize=8:noTabs=false:
|
|
*/
|