Revert "TODO epan/dissectors/asn1/kerberos/packet-kerberos-template.c new GSS flags"

[wireshark-sm.git] / epan / reassemble.c

/* reassemble.c
 * Routines for {fragment,segment} reassembly
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <string.h>

#include <epan/packet.h>
#include <epan/exceptions.h>
#include <epan/reassemble.h>
#include <epan/tvbuff-int.h>

#include <wsutil/str_util.h>
#include <wsutil/ws_assert.h>

/*
 * Functions for reassembly tables where the endpoint addresses, and a
 * fragment ID, are used as the key.
 */
typedef struct _fragment_addresses_key {
        address src;
        address dst;
        uint32_t id;
} fragment_addresses_key;

GList* reassembly_table_list;

static unsigned
fragment_addresses_hash(const void *k)
{
        const fragment_addresses_key* key = (const fragment_addresses_key*) k;
        unsigned hash_val;
/*
        int i;
*/

        hash_val = 0;

/*      More than likely: in most captures src and dst addresses are the
        same, and would hash the same.
        We only use id as the hash as an optimization.

        for (i = 0; i < key->src.len; i++)
                hash_val += key->src.data[i];
        for (i = 0; i < key->dst.len; i++)
                hash_val += key->dst.data[i];
*/

        hash_val += key->id;

        return hash_val;
}

static int
fragment_addresses_equal(const void *k1, const void *k2)
{
        const fragment_addresses_key* key1 = (const fragment_addresses_key*) k1;
        const fragment_addresses_key* key2 = (const fragment_addresses_key*) k2;

        /*
         * key.id is the first item to compare since it's the item most
         * likely to differ between sessions, thus short-circuiting
         * the comparison of addresses.
         */
        return (key1->id == key2->id) &&
               (addresses_equal(&key1->src, &key2->src)) &&
               (addresses_equal(&key1->dst, &key2->dst));
}

/*
 * Create a fragment key for temporary use; it can point to non-
 * persistent data, and so must only be used to look up and
 * delete entries, not to add them.
 */
static void *
fragment_addresses_temporary_key(const packet_info *pinfo, const uint32_t id,
                                 const void *data _U_)
{
        fragment_addresses_key *key = g_slice_new(fragment_addresses_key);

        /*
         * Do a shallow copy of the addresses.
         */
        copy_address_shallow(&key->src, &pinfo->src);
        copy_address_shallow(&key->dst, &pinfo->dst);
        key->id = id;

        return (void *)key;
}

/*
 * Create a fragment key for permanent use; it must point to persistent
 * data, so that it can be used to add entries.
 */
static void *
fragment_addresses_persistent_key(const packet_info *pinfo, const uint32_t id,
                                  const void *data _U_)
{
        fragment_addresses_key *key = g_slice_new(fragment_addresses_key);

        /*
         * Do a deep copy of the addresses.
         */
        copy_address(&key->src, &pinfo->src);
        copy_address(&key->dst, &pinfo->dst);
        key->id = id;

        return (void *)key;
}

static void
fragment_addresses_free_temporary_key(void *ptr)
{
        fragment_addresses_key *key = (fragment_addresses_key *)ptr;
        g_slice_free(fragment_addresses_key, key);
}

static void
fragment_addresses_free_persistent_key(void *ptr)
{
        fragment_addresses_key *key = (fragment_addresses_key *)ptr;

        if(key){
                /*
                 * Free up the copies of the addresses from the old key.
                 */
                free_address(&key->src);
                free_address(&key->dst);

                g_slice_free(fragment_addresses_key, key);
        }
}

const reassembly_table_functions
addresses_reassembly_table_functions = {
        fragment_addresses_hash,
        fragment_addresses_equal,
        fragment_addresses_temporary_key,
        fragment_addresses_persistent_key,
        fragment_addresses_free_temporary_key,
        fragment_addresses_free_persistent_key
};

/*
 * Functions for reassembly tables where the endpoint addresses and ports,
 * and a fragment ID, are used as the key.
 */
typedef struct _fragment_addresses_ports_key {
        address src_addr;
        address dst_addr;
        uint32_t src_port;
        uint32_t dst_port;
        uint32_t id;
} fragment_addresses_ports_key;

static unsigned
fragment_addresses_ports_hash(const void *k)
{
        const fragment_addresses_ports_key* key = (const fragment_addresses_ports_key*) k;
        unsigned hash_val;
/*
        int i;
*/

        hash_val = 0;

/*      More than likely: in most captures src and dst addresses and ports
        are the same, and would hash the same.
        We only use id as the hash as an optimization.

        for (i = 0; i < key->src.len; i++)
                hash_val += key->src_addr.data[i];
        for (i = 0; i < key->dst.len; i++)
                hash_val += key->dst_addr.data[i];
        hash_val += key->src_port;
        hash_val += key->dst_port;
*/

        hash_val += key->id;

        return hash_val;
}

static int
fragment_addresses_ports_equal(const void *k1, const void *k2)
{
        const fragment_addresses_ports_key* key1 = (const fragment_addresses_ports_key*) k1;
        const fragment_addresses_ports_key* key2 = (const fragment_addresses_ports_key*) k2;

        /*
         * key.id is the first item to compare since it's the item most
         * likely to differ between sessions, thus short-circuiting
         * the comparison of addresses and ports.
         */
        return (key1->id == key2->id) &&
               (addresses_equal(&key1->src_addr, &key2->src_addr)) &&
               (addresses_equal(&key1->dst_addr, &key2->dst_addr)) &&
               (key1->src_port == key2->src_port) &&
               (key1->dst_port == key2->dst_port);
}

/*
 * Create a fragment key for temporary use; it can point to non-
 * persistent data, and so must only be used to look up and
 * delete entries, not to add them.
 */
static void *
fragment_addresses_ports_temporary_key(const packet_info *pinfo, const uint32_t id,
                                       const void *data _U_)
{
        fragment_addresses_ports_key *key = g_slice_new(fragment_addresses_ports_key);

        /*
         * Do a shallow copy of the addresses.
         */
        copy_address_shallow(&key->src_addr, &pinfo->src);
        copy_address_shallow(&key->dst_addr, &pinfo->dst);
        key->src_port = pinfo->srcport;
        key->dst_port = pinfo->destport;
        key->id = id;

        return (void *)key;
}

/*
 * Create a fragment key for permanent use; it must point to persistent
 * data, so that it can be used to add entries.
 */
static void *
fragment_addresses_ports_persistent_key(const packet_info *pinfo,
                                        const uint32_t id, const void *data _U_)
{
        fragment_addresses_ports_key *key = g_slice_new(fragment_addresses_ports_key);

        /*
         * Do a deep copy of the addresses.
         */
        copy_address(&key->src_addr, &pinfo->src);
        copy_address(&key->dst_addr, &pinfo->dst);
        key->src_port = pinfo->srcport;
        key->dst_port = pinfo->destport;
        key->id = id;

        return (void *)key;
}

static void
fragment_addresses_ports_free_temporary_key(void *ptr)
{
        fragment_addresses_ports_key *key = (fragment_addresses_ports_key *)ptr;
        g_slice_free(fragment_addresses_ports_key, key);
}

static void
fragment_addresses_ports_free_persistent_key(void *ptr)
{
        fragment_addresses_ports_key *key = (fragment_addresses_ports_key *)ptr;

        if(key){
                /*
                 * Free up the copies of the addresses from the old key.
                 */
                free_address(&key->src_addr);
                free_address(&key->dst_addr);

                g_slice_free(fragment_addresses_ports_key, key);
        }
}

const reassembly_table_functions
addresses_ports_reassembly_table_functions = {
        fragment_addresses_ports_hash,
        fragment_addresses_ports_equal,
        fragment_addresses_ports_temporary_key,
        fragment_addresses_ports_persistent_key,
        fragment_addresses_ports_free_temporary_key,
        fragment_addresses_ports_free_persistent_key
};

typedef struct _reassembled_key {
        uint32_t id;
        uint32_t frame;
} reassembled_key;

static int
reassembled_equal(const void *k1, const void *k2)
{
        const reassembled_key* key1 = (const reassembled_key*) k1;
        const reassembled_key* key2 = (const reassembled_key*) k2;

        /*
         * We assume that the frame numbers are unlikely to be equal,
         * so we check them first.
         */
        return key1->frame == key2->frame && key1->id == key2->id;
}

static unsigned
reassembled_hash(const void *k)
{
        const reassembled_key* key = (const reassembled_key*) k;

        return key->frame;
}

static void
reassembled_key_free(void *ptr)
{
        g_slice_free(reassembled_key, (reassembled_key *)ptr);
}

/*
 * For a fragment hash table entry, free the associated fragments.
 * The entry value (fd_chain) is freed herein and the entry is freed
 * when the key freeing routine is called (as a consequence of returning
 * true from this function).
 */
static gboolean
free_all_fragments(void *key_arg _U_, void *value, void *user_data _U_)
{
        fragment_head *fd_head;
        fragment_item *fd_i = NULL, *tmp_fd;

        /* g_hash_table_new_full() was used to supply a function
         * to free the key and anything to which it points
         */
        fd_head = (fragment_head *)value;
        if (fd_head != NULL) {
                fd_i = fd_head->next;
                if(fd_head->tvb_data && !(fd_head->flags&FD_SUBSET_TVB))
                        tvb_free(fd_head->tvb_data);
                g_slice_free(fragment_head, fd_head);
        }

        for (; fd_i != NULL; fd_i = tmp_fd) {
                tmp_fd=fd_i->next;

                if(fd_i->tvb_data && !(fd_i->flags&FD_SUBSET_TVB))
                        tvb_free(fd_i->tvb_data);
                g_slice_free(fragment_item, fd_i);
        }

        return TRUE;
}

/* ------------------------- */
static fragment_head *new_head(const uint32_t flags)
{
        fragment_head *fd_head;
        /* If head/first structure in list only holds no other data than
        * 'datalen' then we don't have to change the head of the list
        * even if we want to keep it sorted
        */
        fd_head=g_slice_new0(fragment_head);

        fd_head->flags=flags;
        return fd_head;
}

/*
 * For a reassembled-packet hash table entry, free the fragment data
 * to which the value refers. (The key is freed by reassembled_key_free.)
 */
static void
free_fd_head(fragment_head *fd_head)
{
        fragment_item *fd_i, *tmp;

        if (fd_head->flags & FD_SUBSET_TVB)
                fd_head->tvb_data = NULL;
        if (fd_head->tvb_data)
                tvb_free(fd_head->tvb_data);
        for (fd_i = fd_head->next; fd_i; fd_i = tmp) {
                tmp = fd_i->next;
                if (fd_i->flags & FD_SUBSET_TVB)
                        fd_i->tvb_data = NULL;
                if (fd_i->tvb_data) {
                        tvb_free(fd_i->tvb_data);
                }
                g_slice_free(fragment_item, fd_i);
        }
        g_slice_free(fragment_head, fd_head);
}

static void
unref_fd_head(void *data)
{
        fragment_head *fd_head = (fragment_head *) data;
        fd_head->ref_count--;

        if (fd_head->ref_count == 0) {
                free_fd_head(fd_head);
        }
}

static void
reassembled_table_insert(GHashTable *reassembled_table, reassembled_key *key, fragment_head *fd_head)
{
        fragment_head *old_fd_head;
        fd_head->ref_count++;
        if ((old_fd_head = g_hash_table_lookup(reassembled_table, key)) != NULL) {
                if (old_fd_head->ref_count == 1) {
                        /* We're replacing the last entry in the reassembled
                         * table for an old reassembly. Does it have a tvb?
                         * We might still be using that tvb's memory for an
                         * address via set_address_tvb(). (See #19094.)
                         */
                        if (old_fd_head->tvb_data && fd_head->tvb_data) {
                                /* Free it when the new tvb is freed */
                                tvb_set_child_real_data_tvbuff(fd_head->tvb_data, old_fd_head->tvb_data);
                        }
                        /* XXX: Set the old data to NULL regardless. If we
                         * have old data but not new data, that is odd (we're
                         * replacing a reassembly with tvb data with something
                         * with no tvb data, possibly because a zero length or
                         * null tvb was passed into a defragment function,
                         * which is a dissector bug.)
                         * This leaks the tvb data if we couldn't add it to
                         * a new tvb's chain, but we might not be able to free
                         * it yet if set_address_tvb() was used.
                         */
                        old_fd_head->tvb_data = NULL;
                }
        }
        g_hash_table_insert(reassembled_table, key, fd_head);
}

typedef struct register_reassembly_table {
        reassembly_table *table;
        const reassembly_table_functions *funcs;
} register_reassembly_table_t;

/*
 * Register a reassembly table.
 */
void
reassembly_table_register(reassembly_table *table,
                      const reassembly_table_functions *funcs)
{
        register_reassembly_table_t* reg_table;

        DISSECTOR_ASSERT(table);
        DISSECTOR_ASSERT(funcs);

        reg_table = g_new(register_reassembly_table_t,1);

        reg_table->table = table;
        reg_table->funcs = funcs;

        reassembly_table_list = g_list_prepend(reassembly_table_list, reg_table);
}

/*
 * Initialize a reassembly table, with specified functions.
 */
void
reassembly_table_init(reassembly_table *table,
                      const reassembly_table_functions *funcs)
{
        if (table->temporary_key_func == NULL)
                table->temporary_key_func = funcs->temporary_key_func;
        if (table->persistent_key_func == NULL)
                table->persistent_key_func = funcs->persistent_key_func;
        if (table->free_temporary_key_func == NULL)
                table->free_temporary_key_func = funcs->free_temporary_key_func;
        if (table->fragment_table != NULL) {
                /*
                 * The fragment hash table exists.
                 *
                 * Remove all entries and free fragment data for each entry.
                 *
                 * The keys, and anything to which they point, are freed by
                 * calling the table's key freeing function.  The values
                 * are freed in free_all_fragments().
                 */
                g_hash_table_foreach_remove(table->fragment_table,
                                            free_all_fragments, NULL);
        } else {
                /* The fragment table does not exist. Create it */
                table->fragment_table = g_hash_table_new_full(funcs->hash_func,
                    funcs->equal_func, funcs->free_persistent_key_func, NULL);
        }

        if (table->reassembled_table != NULL) {
                /*
                 * The reassembled-packet hash table exists.
                 *
                 * Remove all entries and free reassembled packet
                 * data and key for each entry.
                 */
                g_hash_table_remove_all(table->reassembled_table);
        } else {
                /* The fragment table does not exist. Create it */
                table->reassembled_table = g_hash_table_new_full(reassembled_hash,
                    reassembled_equal, reassembled_key_free, unref_fd_head);
        }
}

/*
 * Destroy a reassembly table.
 */
void
reassembly_table_destroy(reassembly_table *table)
{
        /*
         * Clear the function pointers.
         */
        table->temporary_key_func = NULL;
        table->persistent_key_func = NULL;
        table->free_temporary_key_func = NULL;
        if (table->fragment_table != NULL) {
                /*
                 * The fragment hash table exists.
                 *
                 * Remove all entries and free fragment data for each entry.
                 *
                 * The keys, and anything to which they point, are freed by
                 * calling the table's key freeing function.  The values
                 * are freed in free_all_fragments().
                 */
                g_hash_table_foreach_remove(table->fragment_table,
                                            free_all_fragments, NULL);

                /*
                 * Now destroy the hash table.
                 */
                g_hash_table_destroy(table->fragment_table);
                table->fragment_table = NULL;
        }
        if (table->reassembled_table != NULL) {
                /*
                 * The reassembled-packet hash table exists.
                 *
                 * Remove all entries and free reassembled packet
                 * data and key for each entry.
                 */

                g_hash_table_remove_all(table->reassembled_table);

                /*
                 * Now destroy the hash table.
                 */
                g_hash_table_destroy(table->reassembled_table);
                table->reassembled_table = NULL;
        }
}

/*
 * Look up an fd_head in the fragment table, optionally returning the key
 * for it.
 */
static fragment_head *
lookup_fd_head(reassembly_table *table, const packet_info *pinfo,
               const uint32_t id, const void *data, void * *orig_keyp)
{
        void *key;
        void *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 void *
insert_fd_head(reassembly_table *table, fragment_head *fd_head,
               const packet_info *pinfo, const uint32_t id, const void *data)
{
        void *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 uint32_t id, const void *data)
{
        fragment_head *fd_head;
        fragment_item *fd;
        tvbuff_t *fd_tvb_data=NULL;
        void *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 uint32_t id, const void *data)
{
        return lookup_fd_head(table, pinfo, id, data, NULL);
}

fragment_head *
fragment_get_reassembled_id(reassembly_table *table, const packet_info *pinfo,
                            const uint32_t id)
{
        fragment_head *fd_head;
        reassembled_key key;

        /* create key to search hash with */
        key.frame = pinfo->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 uint32_t id,
                const void *data, const uint32_t fragment_offset)
{
        fragment_head *fd_head;

        fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
        if (!fd_head)
                return;

        /* Resetting the offset is not allowed */
        if ( fd_head->fragment_nr_offset != 0 )
                return;

        fd_head->fragment_nr_offset = fragment_offset;
}

static void
update_first_gap(fragment_head *fd_head, fragment_item *inserted, bool multi_insert)
{
        uint32_t frag_end = inserted->offset + inserted->len;
        fragment_item *iter;
        uint32_t contiguous;

        if (inserted->offset > fd_head->contiguous_len) {
                /* first inserted node is after first gap */
                return;
        } else if (fd_head->first_gap == NULL) {
                /* we haven't seen first fragment yet */
                if (inserted->offset != 0) {
                        /* inserted node is not first fragment */
                        return;
                }
                contiguous = inserted->len;
                iter = inserted;
        } else {
                contiguous = MAX(fd_head->contiguous_len, frag_end);
                iter = multi_insert ? inserted : fd_head->first_gap;
        }

        while (iter->next) {
                if (iter->next->offset > contiguous) {
                        break;
                }
                iter = iter->next;
                contiguous = MAX(contiguous, iter->offset + iter->len);
        }

        /* iter is either pointing to last fragment before gap or tail */
        fd_head->first_gap = iter;
        fd_head->contiguous_len = contiguous;
}

/*
 * Keeping first gap and contiguous length in sync significantly speeds up
 * LINK_FRAG() when fragments in capture file are mostly ordered. However, when
 * fragments are removed from the list, the first gap can point to fragments
 * that were either moved to another list or freed. Therefore when any fragment
 * before first gap is removed, the first gap (and contiguous length) must be
 * invalidated.
 */
static void fragment_reset_first_gap(fragment_head *fd_head)
{
        fd_head->first_gap = NULL;
        fd_head->contiguous_len = 0;
        if (fd_head->next) {
                bool multi_insert = (fd_head->next->next != NULL);
                update_first_gap(fd_head, fd_head->next, multi_insert);
        }
}

/*
 * Determines whether list modification requires first gap reset. On entry
 * modified is NULL if all elements were removed, otherwise it points to
 * element (reachable from fd_head) whose next pointer was changed.
 */
static void fragment_items_removed(fragment_head *fd_head, fragment_item *modified)
{
        if ((fd_head->first_gap == modified) ||
            ((modified != NULL) && (modified->offset > fd_head->contiguous_len))) {
                /* Removed elements were after first gap */
                return;
        }
        fragment_reset_first_gap(fd_head);
}

/*
 * For use with fragment_add (and not the fragment_add_seq functions).
 * When the reassembled result is wrong (perhaps it needs to be extended), this
 * function clears any previous reassembly result, allowing the new reassembled
 * length to be set again.
 */
static void
fragment_reset_defragmentation(fragment_head *fd_head)
{
        /* Caller must ensure that this function is only called when
         * defragmentation is safe to undo. */
        DISSECTOR_ASSERT(fd_head->flags & FD_DEFRAGMENTED);

        for (fragment_item *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;
}

/* 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 uint32_t id, const void *data, const uint32_t tot_len)
{
        fragment_head *fd_head;
        fragment_item *fd;
        uint32_t       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?
         */
        if (fd_head->flags & FD_BLOCKSEQUENCE) {
                for (fd = fd_head->next; fd; fd = fd->next) {
                        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);
                                }
                        }
                }
        }

        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;
}

void
fragment_reset_tot_len(reassembly_table *table, const packet_info *pinfo,
                       const uint32_t id, const void *data, const uint32_t tot_len)
{
        fragment_head *fd_head;

        fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
        if (!fd_head)
                return;

        /*
         * If FD_PARTIAL_REASSEMBLY is set, it would make the next fragment_add
         * call set the reassembled length based on the fragment offset and
         * length. As the length is known now, be sure to disable that magic.
         */
        fd_head->flags &= ~FD_PARTIAL_REASSEMBLY;

        /* If the length is already as expected, there is nothing else to do. */
        if (tot_len == fd_head->datalen)
                return;

        if (fd_head->flags & FD_DEFRAGMENTED) {
                /*
                 * Fragments were reassembled before, clear it to allow
                 * increasing the reassembled length.
                 */
                fragment_reset_defragmentation(fd_head);
        }

        fd_head->datalen = tot_len;
        fd_head->flags |= FD_DATALEN_SET;
}

void
fragment_truncate(reassembly_table *table, const packet_info *pinfo,
                       const uint32_t id, const void *data, const uint32_t tot_len)

{
        tvbuff_t      *old_tvb_data;
        fragment_head *fd_head;

        fd_head = lookup_fd_head(table, pinfo, id, data, NULL);
        if (!fd_head)
                return;

        /* Caller must ensure that this function is only called when
         * we are defragmented. */
        DISSECTOR_ASSERT(fd_head->flags & FD_DEFRAGMENTED);

        /*
         * If FD_PARTIAL_REASSEMBLY is set, it would make the next fragment_add
         * call set the reassembled length based on the fragment offset and
         * length. As the length is known now, be sure to disable that magic.
         */
        fd_head->flags &= ~FD_PARTIAL_REASSEMBLY;

        /* If the length is already as expected, there is nothing else to do. */
        if (tot_len == fd_head->datalen)
                return;

        DISSECTOR_ASSERT(fd_head->datalen > tot_len);

        old_tvb_data=fd_head->tvb_data;
        fd_head->tvb_data = tvb_clone_offset_len(old_tvb_data, 0, tot_len);
        tvb_set_free_cb(fd_head->tvb_data, g_free);

        if (old_tvb_data)
                tvb_add_to_chain(fd_head->tvb_data, old_tvb_data);
        fd_head->datalen = tot_len;

        /* Keep the fragments before the split point, dividing any if
         * necessary.
         * XXX: In rare cases, there might be fragments marked as overlap that
         * have data both before and after the split point, and which only
         * overlap after the split point. In that case, after dividing the
         * fragments the first part no longer overlap.
         * However, at this point we can't test for overlap conflicts,
         * so we'll just leave the overlap flags as-is.
         */
        fd_head->flags &= ~(FD_OVERLAP|FD_OVERLAPCONFLICT|FD_TOOLONGFRAGMENT|FD_MULTIPLETAILS);
        fragment_item *fd_i, *prev_fd = NULL;
        for (fd_i = fd_head->next; fd_i && (fd_i->offset < tot_len); fd_i = fd_i->next) {
                fd_i->flags &= ~(FD_TOOLONGFRAGMENT|FD_MULTIPLETAILS);
                /* Check for the split point occurring in the middle of the
                 * fragment. */
                if (fd_i->offset + fd_i->len > tot_len) {
                        fd_i->len = tot_len - fd_i->offset;
                }
                fd_head->flags |= fd_i->flags & (FD_OVERLAP|FD_OVERLAPCONFLICT);
                prev_fd = fd_i;

                /* Below should do nothing since this is already defragmented */
                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;
        }

        /* Remove all the other fragments, as they are past the split point. */
        if (prev_fd) {
                prev_fd->next = NULL;
        } else {
                fd_head->next = NULL;
        }
        fd_head->contiguous_len = MIN(fd_head->contiguous_len, tot_len);
        fragment_items_removed(fd_head, prev_fd);
        fragment_item *tmp_fd;
        for (; fd_i; fd_i = tmp_fd) {
                tmp_fd=fd_i->next;

                if (fd_i->tvb_data && !(fd_i->flags & FD_SUBSET_TVB))
                        tvb_free(fd_i->tvb_data);
                g_slice_free(fragment_item, fd_i);
        }
}

uint32_t
fragment_get_tot_len(reassembly_table *table, const packet_info *pinfo,
                     const uint32_t 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 uint32_t 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, void *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 uint32_t id)
{
        reassembled_key *new_key;
        fragment_item *fd;

        fd_head->ref_count = 0;
        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->num;
                new_key->id = id;
                reassembled_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;
                        reassembled_table_insert(table->reassembled_table, new_key, fd_head);
                }
        }
        fd_head->flags |= FD_DEFRAGMENTED;
        fd_head->reassembled_in = pinfo->num;
        fd_head->reas_in_layer_num = pinfo->curr_layer_num;
}

/*
 * This function is a variant of the above for the single sequence
 * case, using id+offset (i.e., the original sequence number) for the id
 * in the key.
 */
static void
fragment_reassembled_single(reassembly_table *table, fragment_head *fd_head,
                            const packet_info *pinfo, const uint32_t id)
{
        reassembled_key *new_key;
        fragment_item *fd;

        fd_head->ref_count = 0;
        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->num;
                new_key->id = id;
                reassembled_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 + fd->offset;
                        reassembled_table_insert(table->reassembled_table, new_key, fd_head);
                }
        }
        fd_head->flags |= FD_DEFRAGMENTED;
        fd_head->reassembled_in = pinfo->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 */
        if (fd_head->next == NULL || fd->offset < fd_head->next->offset) {
                /* New first fragment */
                fd->next = fd_head->next;
                fd_head->next = fd;
        } else {
                fd_i = fd_head->next;
                if (fd_head->first_gap != NULL) {
                        if (fd->offset >= fd_head->first_gap->offset) {
                                /* fragment is after first gap */
                                fd_i = fd_head->first_gap;
                        }
                }
                for(; 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;
        }

        update_first_gap(fd_head, fd, false);
}

static void
MERGE_FRAG(fragment_head *fd_head, fragment_item *fd)
{
        fragment_item *fd_i, *tmp, *inserted = fd;
        bool multi_insert;

        if (fd == NULL) return;

        multi_insert = (fd->next != NULL);

        if (fd_head->next == NULL) {
                fd_head->next = fd;
                update_first_gap(fd_head, fd, multi_insert);
                return;
        }

        if ((fd_head->first_gap != NULL) &&
            (fd->offset >= fd_head->first_gap->offset)) {
                /* all new fragments go after first gap */
                fd_i = fd_head->first_gap;
        } else {
                /* at least one new fragment goes before first gap */
                if (fd->offset < fd_head->next->offset) {
                        /* inserted fragment is new head, "swap" the lists */
                        tmp = fd_head->next;
                        fd_head->next = fd;
                        fd = tmp;
                }
                fd_i = fd_head->next;
        }

        /* Traverse the list linked to fragment head ("main" list), checking if
         * fd pointer ("merge" list) should go before or after fd_i->next. Swap
         * fd_i->next ("main") and fd pointers ("merge") if "merge" list should
         * go before iterated element (fd_i). After the swap what formerly was
         * "merge" list essentially becomes part of "main" list (just detached
         * element, i.e. fd, is now head of new "merge list").
         */
        for(; fd_i->next; fd_i=fd_i->next) {
                if (fd->offset < fd_i->next->offset) {
                        tmp = fd_i->next;
                        fd_i->next = fd;
                        fd = tmp;
                }
        }
        /* Reached "main" list end, attach remaining elements */
        fd_i->next = fd;

        update_first_gap(fd_head, inserted, multi_insert);
}

/*
 * 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 bool
fragment_add_work(fragment_head *fd_head, tvbuff_t *tvb, const int offset,
                 const packet_info *pinfo, const uint32_t frag_offset,
                 const uint32_t frag_data_len, const bool more_frags,
                 const uint32_t frag_frame, const bool allow_overlaps)
{
        fragment_item *fd;
        fragment_item *fd_i;
        uint32_t dfpos, fraglen, overlap;
        tvbuff_t *old_tvb_data;
        uint8_t *data;

        /* create new fd describing this fragment */
        fd = g_slice_new(fragment_item);
        fd->next = NULL;
        fd->flags = 0;
        fd->frame = frag_frame;
        fd->offset = frag_offset;
        fd->len  = frag_data_len;
        fd->tvb_data = 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?
                 */
                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.
                                 */
                                fragment_reset_defragmentation(fd_head);
                        } else if (!allow_overlaps) {
                                /*
                                 * 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 with extra
                                         * data, but the calling dissector
                                         * didn't set FD_PARTIAL_REASSEMBLY
                                         * so it won't be handled correctly.
                                         *
                                         * XXX: We could set FD_TOOLONGFRAGMENT
                                         * below instead.
                                         */
                                        THROW_MESSAGE(ReassemblyError, "New fragment overlaps old data (retransmission?)");
                                }
                        }
                } else {
                        /*
                         * No.  That means it overlaps the completed reassembly.
                         * This is probably a retransmission and normal
                         * behavior. (If not, it's because the dissector
                         * doesn't handle reused sequence numbers correctly,
                         * e.g. #10503). Handle below.
                         */
                }
        }

        /* 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) {
                uint32_t end_offset = fd->offset + fd->len;
                fd->flags          |= FD_OVERLAP;
                fd_head->flags |= FD_OVERLAP;
                /* make sure it's not too long */
                /* XXX: We probably don't call this, unlike the _seq()
                 * functions, because we throw an exception above.
                 */
                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. */
        if (fd_head->contiguous_len < 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 = (uint8_t *) 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->next;fd_i;fd_i=fd_i->next) {
                if (fd_i->len) {
                        /*
                         * The contiguous length check above 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_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 (fd_i->offset + fd_i->len < fd_i->offset) {
                                /* Integer overflow, unhandled by rest of
                                 * code so error out. This check handles
                                 * all possible remaining overflows.
                                 */
                                fd_head->error = "offset + len < offset";
                        } else if (!fd_i->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;
                                }
                                overlap = dfpos - fd_i->offset;
                                /* Guaranteed to be >= 0, previous code
                                 * has checked for gaps. */
                                if (overlap) {
                                        /* duplicate/retransmission/overlap */
                                        uint32_t cmp_len = MIN(fd_i->len,overlap);

                                        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;
                                        }
                                }
                                /* XXX: As in the fragment_add_seq funcs
                                 * like fragment_defragment_and_free() the
                                 * existing behavior does not overwrite
                                 * overlapping bytes even if there is a
                                 * conflict. It only adds new bytes.
                                 *
                                 * Since we only add fragments to a reassembly
                                 * if the reassembly isn't complete, the most
                                 * common case for overlap conflicts is when
                                 * an earlier reassembly isn't fully contained
                                 * in the capture, and we've reused an
                                 * indentification number / wrapped around
                                 * offset sequence numbers much later in the
                                 * capture. In that case, we probably *do*
                                 * want to overwrite conflicting bytes, since
                                 * the earlier fragments didn't form a complete
                                 * reassembly and should be effectively thrown
                                 * out rather than mixed with the new ones?
                                 */
                                if (fd_i->offset + fraglen > dfpos) {
                                        memcpy(data+dfpos,
                                                tvb_get_ptr(fd_i->tvb_data, overlap, fraglen-overlap),
                                                fraglen-overlap);
                                        dfpos = fd_i->offset + fraglen;
                                }
                        }

                        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->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 uint32_t id,
                    const void *data, const uint32_t frag_offset,
                    const uint32_t frag_data_len, const bool more_frags,
                    const bool check_already_added,
                    const uint32_t frag_frame)
{
        fragment_head *fd_head;
        fragment_item *fd_item;
        bool already_added;


        /*
         * Dissector shouldn't give us garbage tvb info.
         *
         * XXX - should this code take responsibility for preventing
         * reassembly if data is missing due to the packets being
         * sliced, rather than leaving it up to dissectors?
         */
        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->num, id, frag_offset, frag_data_len, more_frags, pinfo->fd->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->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 (frag_frame <= 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 (frag_frame == 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 (frag_frame > 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, frag_frame, false)) {
                /*
                 * 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 uint32_t id, const void *data,
             const uint32_t frag_offset, const uint32_t frag_data_len,
             const bool more_frags)
{
        return fragment_add_common(table, tvb, offset, pinfo, id, data,
                frag_offset, frag_data_len, more_frags, true, pinfo->num);
}

/*
 * 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 uint32_t id, const void *data,
                         const uint32_t frag_offset,
                         const uint32_t frag_data_len, const bool more_frags)
{
        return fragment_add_common(table, tvb, offset, pinfo, id, data,
                frag_offset, frag_data_len, more_frags, false, pinfo->num);
}

/*
 * For use in protocols like TCP when you are adding an out of order segment
 * that arrived in an earlier frame because the correct fragment id could not
 * be determined until later. By allowing fd->frame to be different than
 * pinfo->num, show_fragment_tree will display the correct fragment numbers.
 *
 * Note that pinfo is still used to set reassembled_in if we have all the
 * fragments, so that results on subsequent passes can be the same as the
 * first pass.
 */
fragment_head *
fragment_add_out_of_order(reassembly_table *table, tvbuff_t *tvb,
                          const int offset, const packet_info *pinfo,
                          const uint32_t id, const void *data,
                          const uint32_t frag_offset,
                          const uint32_t frag_data_len,
                          const bool more_frags, const uint32_t frag_frame)
{
        return fragment_add_common(table, tvb, offset, pinfo, id, data,
                frag_offset, frag_data_len, more_frags, true, frag_frame);
}

fragment_head *
fragment_add_check_with_fallback(reassembly_table *table, tvbuff_t *tvb, const int offset,
                   const packet_info *pinfo, const uint32_t id,
                   const void *data, const uint32_t frag_offset,
                   const uint32_t frag_data_len, const bool more_frags,
                   const uint32_t fallback_frame)
{
        reassembled_key reass_key;
        fragment_head *fd_head;
        void *orig_key;
        bool late_retransmission = false;

        /*
         * If this isn't the first pass, look for this frame in the table
         * of reassembled packets.
         */
        if (pinfo->fd->visited) {
                reass_key.frame = pinfo->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 bool 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) && (fallback_frame != pinfo->num)) {
                /* Check if there is completed reassembly reachable from fallback frame */
                reass_key.frame = fallback_frame;
                reass_key.id = id;
                fd_head = (fragment_head *)g_hash_table_lookup(table->reassembled_table, &reass_key);
                if (fd_head != NULL) {
                        /* Found completely reassembled packet, hash it with current frame number */
                        reassembled_key *new_key = g_slice_new(reassembled_key);
                        new_key->frame = pinfo->num;
                        new_key->id = id;
                        reassembled_table_insert(table->reassembled_table, new_key, fd_head);
                        late_retransmission = true;
                }
        }
        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_bytes_exist(tvb, offset, frag_data_len)) {
                return NULL;
        }

        if (fragment_add_work(fd_head, tvb, offset, pinfo, frag_offset,
                frag_data_len, more_frags, pinfo->num, late_retransmission)) {
                /* Nothing left to do if it was a late retransmission */
                if (late_retransmission) {
                        return fd_head;
                }
                /*
                 * 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;
        }
}

fragment_head *
fragment_add_check(reassembly_table *table, tvbuff_t *tvb, const int offset,
                   const packet_info *pinfo, const uint32_t id,
                   const void *data, const uint32_t frag_offset,
                   const uint32_t frag_data_len, const bool more_frags)
{
        return fragment_add_check_with_fallback(table, tvb, offset, pinfo, id, data,
                frag_offset, frag_data_len, more_frags, pinfo->num);
}

static void
fragment_defragment_and_free (fragment_head *fd_head, const packet_info *pinfo)
{
        fragment_item *fd_i = NULL;
        fragment_item *last_fd = NULL;
        uint32_t dfpos = 0, size = 0;
        tvbuff_t *old_tvb_data = NULL;
        uint8_t *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 = (uint8_t *) 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->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 bool
fragment_add_seq_work(fragment_head *fd_head, tvbuff_t *tvb, const int offset,
                 const packet_info *pinfo, const uint32_t frag_number,
                 const uint32_t frag_data_len, const bool more_frags)
{
        fragment_item *fd;
        fragment_item *fd_i;
        fragment_item *last_fd;
        uint32_t max, dfpos;
        uint32_t 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){
                uint32_t 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->num;
        fd->offset = frag_number_work;
        fd->len  = frag_data_len;
        fd->tvb_data = NULL;

        /* fd_head->frame is the maximum of the frame numbers of all the
         * fragments added to the reassembly. */
        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 ){
                                /* 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 uint32_t id, const void *data,
                        uint32_t frag_number, const uint32_t frag_data_len,
                        const bool more_frags, const uint32_t flags,
                        void * *orig_keyp)
{
        fragment_head *fd_head;
        void *orig_key;

        fd_head = lookup_fd_head(table, pinfo, id, data, &orig_key);

        /* have we already seen this frame ?*/
        if (pinfo->fd->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;
                        /* To save memory, we don't actually copy the
                         * fragment from the tvbuff to the fragment, and in
                         * process_reassembled_data just return back a subset
                         * of the original tvbuff (which must be passed in).
                         */
                        fd_head->len = frag_data_len;
                        fd_head->reassembled_in=pinfo->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->next; fd != NULL; fd = fd->next) {
                                if (fd->next == NULL)
                                        frag_number = fd->offset + 1;
                        }
                }
        }

        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 uint32_t id, const void *data,
                 const uint32_t frag_number, const uint32_t frag_data_len,
                 const bool more_frags, const uint32_t 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 REASSEMBLE_FLAGS_NO_FRAG_NUMBER, it uses the next expected fragment number
 * as the fragment number if there is a reassembly in progress, otherwise
 * it uses 0.
 *
 * If not REASSEMBLE_FLAGS_NO_FRAG_NUMBER, 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 uint32_t id, const void *data,
                            const uint32_t frag_number,
                            const uint32_t frag_data_len,
                            const bool more_frags, const uint32_t flags)
{
        reassembled_key reass_key;
        fragment_head *fd_head;
        void *orig_key;

        /*
         * Have we already seen this frame?
         * If so, look for it in the table of reassembled packets.
         */
        if (pinfo->fd->visited) {
                reass_key.frame = pinfo->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,
                                          &orig_key);
        if (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 uint32_t id,
                       const void *data,
                       const uint32_t frag_number, const uint32_t frag_data_len,
                       const bool 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 uint32_t id, const void *data,
                        const uint32_t frag_number, const uint32_t frag_data_len,
                        const bool 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 uint32_t id,
                      const void *data, const uint32_t frag_data_len,
                      const bool more_frags)
{
        /* Use a dummy frag_number (0), it is ignored since
         * REASSEMBLE_FLAGS_NO_FRAG_NUMBER is set. */
        return fragment_add_seq_check_work(table, tvb, offset, pinfo, id, data,
                                           0, frag_data_len, more_frags,
                                           REASSEMBLE_FLAGS_NO_FRAG_NUMBER);
}

static void
fragment_add_seq_single_move(reassembly_table *table, const packet_info *pinfo,
                             const uint32_t id, const void *data,
                             const uint32_t offset)
{
        fragment_head *fh, *new_fh;
        fragment_item *fd, *prev_fd;
        tvbuff_t *old_tvb_data;
        if (offset == 0) {
                return;
        }
        fh = lookup_fd_head(table, pinfo, id, data, NULL);
        if (fh == NULL) {
                /* Shouldn't be called this way.
                 * Probably wouldn't hurt to just create fh in this case. */
                ws_assert_not_reached();
                return;
        }
        if (fh->flags & FD_DATALEN_SET && fh->datalen <= offset) {
                /* Don't take from past the end. <= because we don't
                 * want to take a First fragment from the next one
                 * either */
                return;
        }
        new_fh = lookup_fd_head(table, pinfo, id+offset, data, NULL);
        if (new_fh != NULL) {
                /* Attach to the end of the sorted list. */
                prev_fd = NULL;
                for(fd = fh->next; fd != NULL; fd=fd->next) {
                    prev_fd = fd;
                }
                /* Don't take a reassembly starting with a First fragment. */
                fd = new_fh->next;
                if (fd && fd->offset != 0) {
                        fragment_item *inserted = fd;
                        bool multi_insert = (inserted->next != NULL);
                        if (prev_fd) {
                                prev_fd->next = fd;
                        } else {
                                fh->next = fd;
                        }
                        for (; fd; fd=fd->next) {
                                fd->offset += offset;
                                if (fh->frame < fd->frame) {
                                        fh->frame = fd->frame;
                                }
                        }
                        update_first_gap(fh, inserted, multi_insert);
                        /* If previously found a Last fragment,
                         * transfer that info to the new one. */
                        if (new_fh->flags & FD_DATALEN_SET) {
                                fh->flags |= FD_DATALEN_SET;
                                fh->datalen = new_fh->datalen + offset;
                        }
                        /* Now remove and delete */
                        new_fh->next = NULL;
                        old_tvb_data = fragment_delete(table, pinfo, id+offset, data);
                        if (old_tvb_data)
                                tvb_free(old_tvb_data);
                }
        }
}

static fragment_head *
fragment_add_seq_single_work(reassembly_table *table, tvbuff_t *tvb,
                             const int offset, const packet_info *pinfo,
                             const uint32_t id, const void* data,
                             const uint32_t frag_data_len,
                             const bool first, const bool last,
                             const uint32_t max_frags, const uint32_t max_age,
                             const uint32_t flags)
{
        reassembled_key reass_key;
        tvbuff_t *old_tvb_data;
        void *orig_key;
        fragment_head *fh, *new_fh;
        fragment_item *fd, *prev_fd;
        uint32_t frag_number, tmp_offset;
        /* Have we already seen this frame?
         * If so, look for it in the table of reassembled packets.
         * Note here we store in the reassembly table by the single sequence
         * number rather than the sequence number of the First fragment. */
        if (pinfo->fd->visited) {
                reass_key.frame = pinfo->num;
                reass_key.id = id;
                fh = (fragment_head *)g_hash_table_lookup(table->reassembled_table, &reass_key);
                return fh;
        }
        /* First let's figure out where we want to add our new fragment */
        fh = NULL;
        if (first) {
                frag_number = 0;
                fh = lookup_fd_head(table, pinfo, id-frag_number, data, NULL);
                if ((flags & REASSEMBLE_FLAGS_AGING) &&
                    fh && ((fh->frame + max_age) < pinfo->num)) {
                        old_tvb_data = fragment_delete(table, pinfo, id-frag_number, data);
                        if (old_tvb_data)
                                tvb_free(old_tvb_data);
                        fh = NULL;
                }
                if (fh == NULL) {
                        /* Not found. Create list-head. */
                        fh = new_head(FD_BLOCKSEQUENCE);
                        insert_fd_head(table, fh, pinfo, id-frag_number, data);
                }
                /* As this is the first fragment, we might have added segments
                 * for this reassembly to the previous one in-progress. */
                fd = NULL;
                for (frag_number=1; frag_number < max_frags; frag_number++) {
                        new_fh = lookup_fd_head(table, pinfo, id-frag_number, data, NULL);
                        if (new_fh != NULL) {
                                prev_fd = NULL;
                                new_fh->frame = 0;
                                for (fd=new_fh->next; fd && fd->offset < frag_number; fd=fd->next) {
                                        prev_fd = fd;
                                        if (new_fh->frame < fd->frame) {
                                                new_fh->frame = fd->frame;
                                        }
                                }
                                if (prev_fd) {
                                        prev_fd->next = NULL;
                                } else {
                                        new_fh->next = NULL;
                                }
                                fragment_items_removed(new_fh, prev_fd);
                                break;
                        }
                }
                if (fd != NULL) {
                        tmp_offset = 0;
                        for (prev_fd = fd; prev_fd; prev_fd = prev_fd->next) {
                                prev_fd->offset -= frag_number;
                                tmp_offset = prev_fd->offset;
                                if (fh->frame < prev_fd->frame) {
                                        fh->frame = prev_fd->frame;
                                }
                        }
                        MERGE_FRAG(fh, fd);
                        if (new_fh != NULL) {
                                /* If we've moved a Last packet, change datalen.
                                 * Second part of this test prob. redundant? */
                                if (new_fh->flags & FD_DATALEN_SET &&
                                    new_fh->datalen >= frag_number) {
                                        fh->flags |= FD_DATALEN_SET;
                                        fh->datalen = new_fh->datalen - frag_number;
                                        new_fh->flags &= ~FD_DATALEN_SET;
                                        new_fh->datalen = 0;
                                }
                                /* If we've moved all the fragments,
                                 * delete the old head */
                                if (new_fh->next == NULL) {
                                        old_tvb_data = fragment_delete(table, pinfo, id-frag_number, data);
                                        if (old_tvb_data)
                                                tvb_free(old_tvb_data);
                                }
                        } else {
                        /* Look forward and take off the next (this is
                         * necessary in some edge cases where max_frags
                         * prevented some fragments from going on the
                         * previous First, but they can go on this one. */
                                fragment_add_seq_single_move(table, pinfo, id,
                                                             data, tmp_offset);
                        }
                }
                frag_number = 0; /* For the rest of the function */
        } else {
                for (frag_number=1; frag_number < max_frags; frag_number++) {
                        fh = lookup_fd_head(table, pinfo, id-frag_number, data, NULL);
                        if ((flags & REASSEMBLE_FLAGS_AGING) &&
                            fh && ((fh->frame + max_age) < pinfo->num)) {
                                old_tvb_data = fragment_delete(table, pinfo, id-frag_number, data);
                                if (old_tvb_data)
                                        tvb_free(old_tvb_data);
                                fh = NULL;
                        }
                        if (fh != NULL) {
                                if (fh->flags & FD_DATALEN_SET &&
                                    fh->datalen < frag_number) {
                                        /* This fragment is after the Last
                                         * fragment, so must go after here. */
                                        fh = NULL;
                                }
                                break;
                        }
                }
                if (fh == NULL) { /* Didn't find location, use default */
                        frag_number = 1;
                        /* Already looked for frag_number 1, so just create */
                        fh = new_head(FD_BLOCKSEQUENCE);
                        insert_fd_head(table, fh, pinfo, id-frag_number, data);
                }
        }
        if (last) {
                /* Look for fragments past the end set by this Last fragment. */
                prev_fd = NULL;
                for (fd=fh->next; fd && fd->offset <= frag_number; fd=fd->next) {
                        prev_fd = fd;
                }
                /* fd is now all fragments offset > frag_number (the Last).
                 * It shouldn't have a fragment with offset frag_number+1,
                 * as that would be a First fragment not marked as such.
                 * However, this can happen if we had unreassembled fragments
                 * (missing, or at the start of the capture) and we've also
                 * looped around on the sequence numbers. It can also happen
                 * if bit errors mess up Last or First. */
                if (fd != NULL) {
                        if (prev_fd) {
                                prev_fd->next = NULL;
                        } else {
                            fh->next = NULL;
                        }
                        fragment_items_removed(fh, prev_fd);
                        fh->frame = 0;
                        for (prev_fd=fh->next; prev_fd; prev_fd=prev_fd->next) {
                                if (fh->frame < prev_fd->frame) {
                                        fh->frame = prev_fd->frame;
                                }
                        }
                        while (fd && fd->offset == frag_number+1) {
                                /* Definitely have bad data here. Best to
                                 * delete these and leave unreassembled. */
                                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;
                        }
                }
                if (fd != NULL) {
                        /* Move these onto the next frame. */
                        new_fh = lookup_fd_head(table, pinfo, id+1, data, NULL);
                        if (new_fh==NULL) {
                                /* Not found. Create list-head. */
                                new_fh = new_head(FD_BLOCKSEQUENCE);
                                insert_fd_head(table, new_fh, pinfo, id+1, data);
                        }
                        tmp_offset = 0;
                        for (prev_fd = fd; prev_fd; prev_fd = prev_fd->next) {
                                prev_fd->offset -= (frag_number+1);
                                tmp_offset = prev_fd->offset;
                                if (new_fh->frame < fd->frame) {
                                        new_fh->frame = fd->frame;
                                }
                        }
                        MERGE_FRAG(new_fh, fd);
                        /* If we previously found a different Last fragment,
                         * transfer that information to the new reassembly. */
                        if (fh->flags & FD_DATALEN_SET &&
                            fh->datalen > frag_number) {
                                new_fh->flags |= FD_DATALEN_SET;
                                new_fh->datalen = fh->datalen - (frag_number+1);
                                fh->flags &= ~FD_DATALEN_SET;
                                fh->datalen = 0;
                        } else {
                        /* Look forward and take off the next (this is
                         * necessary in some edge cases where max_frags
                         * prevented some fragments from going on the
                         * previous First, but they can go on this one. */
                                fragment_add_seq_single_move(table, pinfo, id+1,
                                                             data, tmp_offset);
                        }
                }
        } else {
                fragment_add_seq_single_move(table, pinfo, id-frag_number, data,
                                             frag_number+1);
        }
        /* Having cleaned up everything, finally ready to add our new
         * fragment. Note that only this will ever complete a reassembly. */
        fh = fragment_add_seq_common(table, tvb, offset, pinfo,
                                         id-frag_number, data,
                                         frag_number, frag_data_len,
                                         !last, 0, &orig_key);
        if (fh) {
                /*
                 * 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_single(table, fh, pinfo, id-frag_number);
                return fh;
        } else {
                /*
                 * Reassembly isn't complete.
                 */
                return NULL;
        }
}

fragment_head *
fragment_add_seq_single(reassembly_table *table, tvbuff_t *tvb,
                             const int offset, const packet_info *pinfo,
                             const uint32_t id, const void* data,
                             const uint32_t frag_data_len,
                             const bool first, const bool last,
                             const uint32_t max_frags)
{
        return fragment_add_seq_single_work(table, tvb, offset, pinfo,
                                            id, data, frag_data_len,
                                            first, last, max_frags, 0, 0);
}

fragment_head *
fragment_add_seq_single_aging(reassembly_table *table, tvbuff_t *tvb,
                             const int offset, const packet_info *pinfo,
                             const uint32_t id, const void* data,
                             const uint32_t frag_data_len,
                             const bool first, const bool last,
                             const uint32_t max_frags, const uint32_t max_age)
{
        return fragment_add_seq_single_work(table, tvb, offset, pinfo,
                                            id, data, frag_data_len,
                                            first, last, max_frags, max_age,
                                            REASSEMBLE_FLAGS_AGING);
}

void
fragment_start_seq_check(reassembly_table *table, const packet_info *pinfo,
                         const uint32_t id, const void *data,
                         const uint32_t tot_len)
{
        fragment_head *fd_head;

        /* Have we already seen this frame ?*/
        if (pinfo->fd->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->first_gap = NULL;
                fd_head->contiguous_len = 0;
                fd_head->frame = 0;
                fd_head->len = 0;
                fd_head->fragment_nr_offset = 0;
                fd_head->datalen = tot_len;
                fd_head->reassembled_in = 0;
                fd_head->reas_in_layer_num = 0;
                fd_head->flags = FD_BLOCKSEQUENCE|FD_DATALEN_SET;
                fd_head->tvb_data = NULL;
                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 uint32_t id, const void *data)
{
        reassembled_key reass_key;
        reassembled_key *new_key;
        fragment_head *fd_head;
        fragment_item *fd;
        void *orig_key;
        uint32_t max_offset = 0;

        /*
         * Have we already seen this frame?
         * If so, look for it in the table of reassembled packets.
         */
        if (pinfo->fd->visited) {
                reass_key.frame = pinfo->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) {
                for (fd = fd_head->next; fd; fd = fd->next) {
                        if (fd->offset > max_offset) {
                                max_offset = fd->offset;
                        }
                }
                fd_head->datalen = max_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->num;
                        new_key->id = id;
                        reassembled_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.
 * offset from start of tvb, result up to end of tvb
 */
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,
        bool *update_col_infop, proto_tree *tree)
{
        tvbuff_t *next_tvb;
        bool update_col_info;
        proto_item *frag_tree_item;

        if (fd_head != NULL && pinfo->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, a subset of the
                         * tvbuff passed in. (The dissector SHOULD pass in
                         * the correct tvbuff and offset.)
                         */
                        int len;
                        /* For FD_BLOCKSEQUENCE, len is the length in bytes,
                         * datalen is the number of fragments.
                         */
                        if (fd_head->flags & FD_BLOCKSEQUENCE) {
                                len = fd_head->len;
                        } else {
                                // XXX Do the non-seq functions have this optimization?
                                len = fd_head->datalen;
                        }
                        next_tvb = tvb_new_subset_length(tvb, offset, len);
                        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_item *fei = proto_tree_add_uint(tree,
                                *(fit->hf_reassembled_in), tvb,
                                0, 0, fd_head->reassembled_in);
                        proto_item_set_generated(fei);
                }
        }
        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 bool first_frag,
        const uint32_t count, tvbuff_t *tvb, packet_info *pinfo)
{
        proto_item *fei=NULL;
        int hf;

        if (first_frag) {
                char *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, 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 bool
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.
*/
bool
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;
        bool first_frag;
        uint32_t 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.
*/
bool
show_fragment_seq_tree(fragment_head *fd_head, const fragment_items *fit,
        proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, proto_item **fi)
{
        uint32_t offset, next_offset, count = 0;
        fragment_item *fd, *last_fd;
        proto_tree *ft;
        bool 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);
}

static void
reassembly_table_init_reg_table(void *p, void *user_data _U_)
{
        register_reassembly_table_t* reg_table = (register_reassembly_table_t*)p;
        reassembly_table_init(reg_table->table, reg_table->funcs);
}

static void
reassembly_table_init_reg_tables(void)
{
        g_list_foreach(reassembly_table_list, reassembly_table_init_reg_table, NULL);
}

static void
reassembly_table_cleanup_reg_table(void *p, void *user_data _U_)
{
        register_reassembly_table_t* reg_table = (register_reassembly_table_t*)p;
        reassembly_table_destroy(reg_table->table);
}

static void
reassembly_table_cleanup_reg_tables(void)
{
        g_list_foreach(reassembly_table_list, reassembly_table_cleanup_reg_table, NULL);
}

void reassembly_tables_init(void)
{
        register_init_routine(&reassembly_table_init_reg_tables);
        register_cleanup_routine(&reassembly_table_cleanup_reg_tables);
}

static void
reassembly_table_free(void *p, void *user_data _U_)
{
        register_reassembly_table_t* reg_table = (register_reassembly_table_t*)p;
        reassembly_table_destroy(reg_table->table);
        g_free(reg_table);
}

void
reassembly_table_cleanup(void)
{
        g_list_foreach(reassembly_table_list, reassembly_table_free, NULL);
        g_list_free(reassembly_table_list);
}

/* One instance of this structure is created for each pdu that spans across
 * multiple segments. (MSP) */
typedef struct _multisegment_pdu_t {
        uint64_t first_frame;
        uint64_t last_frame;
        unsigned start_offset_at_first_frame;
        unsigned end_offset_at_last_frame;
        int length; /* length of this MSP */
        uint32_t streaming_reassembly_id;
        /* pointer to previous multisegment_pdu */
        struct _multisegment_pdu_t* prev_msp;
} multisegment_pdu_t;

/* struct for keeping the reassembly information of each stream */
struct streaming_reassembly_info_t {
        /* This map is keyed by frame num and keeps track of all MSPs for this
         * stream. Different frames will point to the same MSP if they contain
         * part data of this MSP. If a frame contains data that
         * belongs to two MSPs, it will point to the second MSP. */
        wmem_map_t* multisegment_pdus;
        /* This map is keyed by frame num and keeps track of the frag_offset
         * of the first byte of frames for fragment_add() after first scan. */
        wmem_map_t* frame_num_frag_offset_map;
        /* how many bytes the current uncompleted MSP still needs. (only valid for first scan) */
        int prev_deseg_len;
        /* the current uncompleted MSP (only valid for first scan) */
        multisegment_pdu_t* last_msp;
};

static uint32_t
create_streaming_reassembly_id(void)
{
        static uint32_t global_streaming_reassembly_id = 0;
        return ++global_streaming_reassembly_id;
}

streaming_reassembly_info_t*
streaming_reassembly_info_new(void)
{
        return wmem_new0(wmem_file_scope(), streaming_reassembly_info_t);
}

/* Following is an example of ProtoA and ProtoB protocols from the declaration of this function in 'reassemble.h':
 *
 *                 +------------------ A Multisegment PDU of ProtoB ----------------------+
 *                 |                                                                      |
 * +--- ProtoA payload1 ---+   +- payload2 -+  +- Payload3 -+  +- Payload4 -+   +- ProtoA payload5 -+
 * | EoMSP | OmNFP | BoMSP |   |    MoMSP   |  |    MoMSP   |  |    MoMSP   |   |  EoMSP  |  BoMSP  |
 * +-------+-------+-------+   +------------+  +------------+  +------------+   +---------+---------+
 *                 |                                                                      |
 *                 +----------------------------------------------------------------------+
 *
 * For a ProtoA payload composed of EoMSP + OmNFP + BoMSP will call fragment_add() twice on EoMSP and BoMSP; and call
 * process_reassembled_data() once for generating tvb of a MSP to which EoMSP belongs; and call subdissector twice on
 * reassembled MSP of EoMSP and OmNFP + BoMSP. After that finds BoMSP is a beginning of a MSP at first scan.
 *
 * The rules are:
 *
 *  - If a ProtoA payload contains EoMSP, we will need call fragment_add(), process_reassembled_data() and subdissector
 *    once on it to end a MSP. (May run twice or more times at first scan, because subdissector may only return the
 *    head length of message by pinfo->desegment_len. We need run second time for subdissector to determine the length
 *    of entire message).
 *
 * - If a ProtoA payload contains OmNFP, we will need only call subdissector once on it. The subdissector need dissect
 *    all non-fragment PDUs in it. (no desegment_len should output)
 *
 *  - If a ProtoA payload contains BoMSP, we will need call subdissector once on BoMSP or OmNFP+BoMSP (because unknown
 *    during first scan). The subdissector will output desegment_len (!= 0). Then we will call fragment_add()
 *    with a new reassembly id on BoMSP for starting a new MSP.
 *
 *  - If a ProtoA payload only contains MoMSP (entire payload is part of a MSP), we will only call fragment_add() once
 *    or twice (at first scan) on it. The subdissector will not be called.
 *
 * In this implementation, only multisegment PDUs are recorded in multisegment_pdus map keyed by the numbers (uint64_t)
 * of frames belongs to MSPs. Each MSP in the map has a pointer referred to previous MSP, because we may need
 * two MSPs to dissect a ProtoA payload that contains EoMSP + BoMSP at the same time. The multisegment_pdus map is built
 * during first scan (pinfo->visited == false) with help of prev_deseg_len and last_msp fields of streaming_reassembly_info_t
 * for each direction of a ProtoA STREAM. The prev_deseg_len record how many bytes of subsequent ProtoA payloads belong to
 * previous PDU during first scan. The last_msp member of streaming_reassembly_info_t is always point to last MSP which
 * is created during scan previous or early ProtoA payloads. Since subdissector might return only the head length of entire
 * message (by pinfo->desegment_len) when there is not enough data to determine the message length, we need to reopen
 * reassembly fragments for adding more bytes during scanning the next ProtoA payload. We have to use fragment_add()
 * instead of fragment_add_check() or fragment_add_seq_next().
 *
 * Read more: please refer to comments of the declaration of this function in 'reassemble.h'.
 */
int
reassemble_streaming_data_and_call_subdissector(
        tvbuff_t* tvb, packet_info* pinfo, unsigned offset, int length,
        proto_tree* segment_tree, proto_tree* reassembled_tree, reassembly_table streaming_reassembly_table,
        streaming_reassembly_info_t* reassembly_info, uint64_t cur_frame_num,
        dissector_handle_t subdissector_handle, proto_tree* subdissector_tree, void* subdissector_data,
        const char* label, const fragment_items* frag_hf_items, int hf_segment_data
)
{
        int orig_length = length;
        int datalen = 0;
        int bytes_belong_to_prev_msp = 0; /* bytes belong to previous MSP */
        uint32_t reassembly_id = 0, frag_offset = 0;
        fragment_head* head = NULL;
        bool need_more = false;
        bool found_BoMSP = false;
        multisegment_pdu_t* cur_msp = NULL, * prev_msp = NULL;
        uint16_t save_can_desegment;
        int save_desegment_offset;
        uint32_t save_desegment_len;
        uint64_t* frame_ptr;

        save_can_desegment = pinfo->can_desegment;
        save_desegment_offset = pinfo->desegment_offset;
        save_desegment_len = pinfo->desegment_len;

        /* calculate how many bytes of this payload belongs to previous MSP (EoMSP) */
        if (!PINFO_FD_VISITED(pinfo)) {
                /* this is first scan */
                if (reassembly_info->prev_deseg_len == DESEGMENT_ONE_MORE_SEGMENT) {
                        /* assuming the entire tvb belongs to the previous MSP */
                        bytes_belong_to_prev_msp = length;
                        reassembly_info->prev_deseg_len = length;
                } else if (reassembly_info->prev_deseg_len > 0) {
                        /* part or all of current payload belong to previous MSP */
                        bytes_belong_to_prev_msp = MIN(reassembly_info->prev_deseg_len, length);
                        reassembly_info->prev_deseg_len -= bytes_belong_to_prev_msp;
                        need_more = (reassembly_info->prev_deseg_len > 0);
                } /* else { beginning of a new PDU (might be a NFP or MSP) } */

                if (bytes_belong_to_prev_msp > 0) {
                        DISSECTOR_ASSERT(reassembly_info->last_msp != NULL);
                        reassembly_id = reassembly_info->last_msp->streaming_reassembly_id;
                        frag_offset = reassembly_info->last_msp->length;
                        if (reassembly_info->frame_num_frag_offset_map == NULL) {
                                reassembly_info->frame_num_frag_offset_map = wmem_map_new(wmem_file_scope(), g_int64_hash, g_int64_equal);
                        }
                        frame_ptr = (uint64_t*)wmem_memdup(wmem_file_scope(), &cur_frame_num, sizeof(uint64_t));
                        wmem_map_insert(reassembly_info->frame_num_frag_offset_map, frame_ptr, GUINT_TO_POINTER(frag_offset));
                        /* This payload contains the data of previous msp, so we point to it. That may be overridden late. */
                        wmem_map_insert(reassembly_info->multisegment_pdus, frame_ptr, reassembly_info->last_msp);
                }
        } else {
                /* not first scan, use information of multisegment_pdus built during first scan */
                if (reassembly_info->multisegment_pdus) {
                        cur_msp = (multisegment_pdu_t*)wmem_map_lookup(reassembly_info->multisegment_pdus, &cur_frame_num);
                }
                if (cur_msp) {
                        if (cur_msp->first_frame == cur_frame_num) {
                                /* Current payload contains a beginning of a MSP. (BoMSP)
                                 * The cur_msp contains information about the beginning MSP.
                                 * If prev_msp is not null, that means this payload also contains
                                 * the last part of previous MSP. (EoMSP) */
                                prev_msp = cur_msp->prev_msp;
                        } else {
                                /* Current payload is not a first frame of a MSP (not include BoMSP). */
                                prev_msp = cur_msp;
                                cur_msp = NULL;
                        }
                }

                if (prev_msp && prev_msp->last_frame >= cur_frame_num) {
                        if (prev_msp->last_frame == cur_frame_num) {
                                /* this payload contains part of previous MSP (contains EoMSP) */
                                bytes_belong_to_prev_msp = prev_msp->end_offset_at_last_frame - offset;
                        } else { /* if (prev_msp->last_frame > cur_frame_num) */
                            /* this payload all belongs to previous MSP */
                                bytes_belong_to_prev_msp = length;
                                need_more = true;
                        }
                        reassembly_id = prev_msp->streaming_reassembly_id;
                }
                if (reassembly_info->frame_num_frag_offset_map) {
                        frag_offset = GPOINTER_TO_UINT(wmem_map_lookup(reassembly_info->frame_num_frag_offset_map, &cur_frame_num));
                }
        }

        /* handling EoMSP or MoMSP (entire payload being middle part of a MSP) */
        while (bytes_belong_to_prev_msp > 0) {
                tvbuff_t* reassembled_tvb = NULL;
                DISSECTOR_ASSERT(reassembly_id > 0);
                pinfo->can_desegment = 2; /* this will be decreased one while passing to subdissector */
                pinfo->desegment_offset = 0;
                pinfo->desegment_len = 0;

                head = fragment_add(&streaming_reassembly_table, tvb, offset, pinfo, reassembly_id, NULL,
                        frag_offset, bytes_belong_to_prev_msp, need_more);

                if (head) {
                        if (frag_hf_items->hf_reassembled_in) {
                                proto_item_set_generated(
                                        proto_tree_add_uint(segment_tree, *(frag_hf_items->hf_reassembled_in), tvb, offset,
                                                bytes_belong_to_prev_msp, head->reassembled_in)
                                );
                        }

                        if (!need_more) {
                                reassembled_tvb = process_reassembled_data(tvb, offset, pinfo,
                                        wmem_strdup_printf(pinfo->pool, "Reassembled %s", label),
                                        head, frag_hf_items, NULL, reassembled_tree);
                        }
                }

                proto_tree_add_bytes_format(segment_tree, hf_segment_data, tvb, offset,
                        bytes_belong_to_prev_msp, NULL, "%s Segment data (%u byte%s)", label,
                        bytes_belong_to_prev_msp, plurality(bytes_belong_to_prev_msp, "", "s"));

                if (reassembled_tvb) {
                        /* normally, this stage will dissect one or more completed pdus */
                        /* Note, don't call_dissector_with_data because sometime the pinfo->curr_layer_num will changed
                         * after calling that will make reassembly failed! */
                        call_dissector_only(subdissector_handle, reassembled_tvb, pinfo, subdissector_tree, subdissector_data);
                }

                if (pinfo->desegment_len) {
                        /* that must only happen during first scan the reassembly_info->prev_deseg_len might be only the
                         * head length of entire message. */
                        DISSECTOR_ASSERT(!PINFO_FD_VISITED(pinfo));
                        DISSECTOR_ASSERT_HINT(pinfo->desegment_len != DESEGMENT_UNTIL_FIN, "Subdissector MUST NOT "
                                "set pinfo->desegment_len to DESEGMENT_UNTIL_FIN. Instead, it can set pinfo->desegment_len to "
                                " DESEGMENT_ONE_MORE_SEGMENT or the length of head if the length of entire message is not able to be determined.");

                        if (pinfo->desegment_offset > 0) {
                                DISSECTOR_ASSERT_HINT(pinfo->desegment_offset > reassembly_info->last_msp->length
                                        && pinfo->desegment_offset < reassembly_info->last_msp->length + bytes_belong_to_prev_msp,
                                        wmem_strdup_printf(pinfo->pool,
                                                "Subdissector MUST NOT set pinfo->desegment_offset(%d) in previous or next part of MSP, must between (%d, %d).",
                                                pinfo->desegment_offset, reassembly_info->last_msp->length, reassembly_info->last_msp->length + bytes_belong_to_prev_msp));

                                /* shorten the bytes_belong_to_prev_msp and just truncate the reassembled tvb */
                                bytes_belong_to_prev_msp = pinfo->desegment_offset - reassembly_info->last_msp->length;
                                fragment_truncate(&streaming_reassembly_table, pinfo, reassembly_id, NULL, pinfo->desegment_offset);
                                found_BoMSP = true;
                        } else {
                                if (pinfo->desegment_len == DESEGMENT_ONE_MORE_SEGMENT) {
                                        /* just need more bytes, all remaining bytes belongs to previous MSP (to run fragment_add again) */
                                        bytes_belong_to_prev_msp = length;
                                }

                                /* Remove the data added by previous fragment_add(), and reopen fragments for adding more bytes. */
                                fragment_truncate(&streaming_reassembly_table, pinfo, reassembly_id, NULL, reassembly_info->last_msp->length);
                                fragment_set_partial_reassembly(&streaming_reassembly_table, pinfo, reassembly_id, NULL);

                                reassembly_info->prev_deseg_len = bytes_belong_to_prev_msp + pinfo->desegment_len;
                                bytes_belong_to_prev_msp = MIN(reassembly_info->prev_deseg_len, length);
                                reassembly_info->prev_deseg_len -= bytes_belong_to_prev_msp;
                                need_more = (reassembly_info->prev_deseg_len > 0);
                                continue;
                        }
                }

                if (pinfo->desegment_len == 0 || found_BoMSP) {
                        /* We will arrive here, only when the MSP is defragmented and dissected or this
                         * payload all belongs to previous MSP (only fragment_add() with need_more=true called)
                         * or BoMSP is parsed while pinfo->desegment_offset > 0 and pinfo->desegment_len != 0
                         */
                        offset += bytes_belong_to_prev_msp;
                        length -= bytes_belong_to_prev_msp;
                        DISSECTOR_ASSERT(length >= 0);
                        if (!PINFO_FD_VISITED(pinfo)) {
                                reassembly_info->last_msp->length += bytes_belong_to_prev_msp;
                        }

                        if (!PINFO_FD_VISITED(pinfo) && reassembled_tvb) {
                                /* completed current msp */
                                reassembly_info->last_msp->last_frame = cur_frame_num;
                                reassembly_info->last_msp->end_offset_at_last_frame = offset;
                                reassembly_info->prev_deseg_len = pinfo->desegment_len;
                        }
                        bytes_belong_to_prev_msp = 0; /* break */
                }
        }

        /* to find and handle OmNFP, and find BoMSP at first scan. */
        if (length > 0 && !found_BoMSP) {
                if (!PINFO_FD_VISITED(pinfo)) {
                        /* It is first scan, to dissect remaining bytes to find whether it is OmNFP only, or BoMSP only or OmNFP + BoMSP. */
                        datalen = length;
                        DISSECTOR_ASSERT(cur_msp == NULL);
                } else {
                        /* Not first scan */
                        if (cur_msp) {
                                /* There's a BoMSP. Let's calculate the length of OmNFP between EoMSP and BoMSP */
                                datalen = cur_msp->start_offset_at_first_frame - offset; /* if result is zero that means no OmNFP */
                        } else {
                                /* This payload is not a beginning of MSP. The remaining bytes all belong to OmNFP without BoMSP */
                                datalen = length;
                        }
                }
                DISSECTOR_ASSERT(datalen >= 0);

                /* Dissect the remaining of this payload. If (datalen == 0) means remaining only have one BoMSP without OmNFP. */
                if (datalen > 0) {
                        /* we dissect if it is not dissected before or it is a non-fragment pdu (between two multisegment pdus) */
                        pinfo->can_desegment = 2;
                        pinfo->desegment_offset = 0;
                        pinfo->desegment_len = 0;

                        call_dissector_only(subdissector_handle, tvb_new_subset_length(tvb, offset, datalen),
                                pinfo, subdissector_tree, subdissector_data);

                        if (pinfo->desegment_len) {
                                DISSECTOR_ASSERT_HINT(pinfo->desegment_len != DESEGMENT_UNTIL_FIN, "Subdissector MUST NOT "
                                        "set pinfo->desegment_len to DESEGMENT_UNTIL_FIN. Instead, it can set pinfo->desegment_len to "
                                        " DESEGMENT_ONE_MORE_SEGMENT or the length of head if the length of entire message is not able to be determined.");
                                /* only happen during first scan */
                                DISSECTOR_ASSERT(!PINFO_FD_VISITED(pinfo) && datalen == length);
                                offset += pinfo->desegment_offset;
                                length -= pinfo->desegment_offset;
                        } else {
                                /* all remaining bytes are consumed by subdissector */
                                offset += datalen;
                                length -= datalen;
                        }
                        if (!PINFO_FD_VISITED(pinfo)) {
                                reassembly_info->prev_deseg_len = pinfo->desegment_len;
                        }
                } /* else all remaining bytes (BoMSP) belong to a new MSP  */
                DISSECTOR_ASSERT(length >= 0);
        }

        /* handling BoMSP */
        if (length > 0) {
                col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "[%s segment of a reassembled PDU] ", label);
                if (!PINFO_FD_VISITED(pinfo)) {
                        /* create a msp for current frame during first scan */
                        cur_msp = wmem_new0(wmem_file_scope(), multisegment_pdu_t);
                        cur_msp->first_frame = cur_frame_num;
                        cur_msp->last_frame = UINT64_MAX;
                        cur_msp->start_offset_at_first_frame = offset;
                        cur_msp->length = length;
                        cur_msp->streaming_reassembly_id = reassembly_id = create_streaming_reassembly_id();
                        cur_msp->prev_msp = reassembly_info->last_msp;
                        reassembly_info->last_msp = cur_msp;
                        if (reassembly_info->multisegment_pdus == NULL) {
                                reassembly_info->multisegment_pdus = wmem_map_new(wmem_file_scope(), g_int64_hash, g_int64_equal);
                        }
                        frame_ptr = (uint64_t*)wmem_memdup(wmem_file_scope(), &cur_frame_num, sizeof(uint64_t));
                        wmem_map_insert(reassembly_info->multisegment_pdus, frame_ptr, cur_msp);
                } else {
                        DISSECTOR_ASSERT(cur_msp && cur_msp->start_offset_at_first_frame == offset);
                        reassembly_id = cur_msp->streaming_reassembly_id;
                }
                /* add first fragment of the new MSP to reassembly table */
                head = fragment_add(&streaming_reassembly_table, tvb, offset, pinfo, reassembly_id,
                        NULL, 0, length, true);

                if (head && frag_hf_items->hf_reassembled_in) {
                        proto_item_set_generated(
                                proto_tree_add_uint(segment_tree, *(frag_hf_items->hf_reassembled_in),
                                        tvb, offset, length, head->reassembled_in)
                        );
                }
                proto_tree_add_bytes_format(segment_tree, hf_segment_data, tvb, offset, length,
                        NULL, "%s Segment data (%u byte%s)", label, length, plurality(length, "", "s"));
        }

        pinfo->can_desegment = save_can_desegment;
        pinfo->desegment_offset = save_desegment_offset;
        pinfo->desegment_len = save_desegment_len;

        return orig_length;
}

int
additional_bytes_expected_to_complete_reassembly(streaming_reassembly_info_t* reassembly_info)
{
        return reassembly_info->prev_deseg_len;
}

/*
 * Editor modelines  -  https://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:
 */