source: vendor/3.6.0/source4/smb_server/tcon.c

/* 
   Unix SMB/CIFS implementation.
   Manage smbsrv_tcon structures
   Copyright (C) Andrew Tridgell 1998
   Copyright (C) Alexander Bokovoy 2002
   Copyright (C) Stefan Metzmacher 2005-2006
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "smb_server/smb_server.h"
#include "smbd/service_stream.h"
#include "lib/tsocket/tsocket.h"
#include "ntvfs/ntvfs.h"

/****************************************************************************
init the tcon structures
****************************************************************************/
static NTSTATUS smbsrv_init_tcons(struct smbsrv_tcons_context *tcons_ctx, TALLOC_CTX *mem_ctx, uint32_t limit)
{
        /* 
         * the idr_* functions take 'int' as limit,
         * and only work with a max limit 0x00FFFFFF
         */
        limit &= 0x00FFFFFF;

        tcons_ctx->idtree_tid   = idr_init(mem_ctx);
        NT_STATUS_HAVE_NO_MEMORY(tcons_ctx->idtree_tid);
        tcons_ctx->idtree_limit = limit;
        tcons_ctx->list         = NULL;

        return NT_STATUS_OK;
}

NTSTATUS smbsrv_smb_init_tcons(struct smbsrv_connection *smb_conn)
{
        return smbsrv_init_tcons(&smb_conn->smb_tcons, smb_conn, UINT16_MAX);
}

NTSTATUS smbsrv_smb2_init_tcons(struct smbsrv_session *smb_sess)
{
        return smbsrv_init_tcons(&smb_sess->smb2_tcons, smb_sess, UINT32_MAX);
}

/****************************************************************************
find a tcon given a tid for SMB
****************************************************************************/
static struct smbsrv_tcon *smbsrv_tcon_find(struct smbsrv_tcons_context *tcons_ctx,
                                            uint32_t tid, struct timeval request_time)
{
        void *p;
        struct smbsrv_tcon *tcon;

        if (tid == 0) return NULL;

        if (tid > tcons_ctx->idtree_limit) return NULL;

        p = idr_find(tcons_ctx->idtree_tid, tid);
        if (!p) return NULL;

        tcon = talloc_get_type(p, struct smbsrv_tcon);
        if (!tcon) return NULL;

        tcon->statistics.last_request_time = request_time;

        return tcon;
}

struct smbsrv_tcon *smbsrv_smb_tcon_find(struct smbsrv_connection *smb_conn,
                                         uint32_t tid, struct timeval request_time)
{
        return smbsrv_tcon_find(&smb_conn->smb_tcons, tid, request_time);
}

struct smbsrv_tcon *smbsrv_smb2_tcon_find(struct smbsrv_session *smb_sess,
                                          uint32_t tid, struct timeval request_time)
{
        if (!smb_sess) return NULL;
        return smbsrv_tcon_find(&smb_sess->smb2_tcons, tid, request_time);
}

/*
  destroy a connection structure
*/
static int smbsrv_tcon_destructor(struct smbsrv_tcon *tcon)
{
        struct smbsrv_tcons_context *tcons_ctx;
        struct tsocket_address *client_addr;

        client_addr = tcon->smb_conn->connection->remote_address;

        DEBUG(3,("%s closed connection to service %s\n",
                 tsocket_address_string(client_addr, tcon),
                 tcon->share_name));

        /* tell the ntvfs backend that we are disconnecting */
        if (tcon->ntvfs) {
                ntvfs_disconnect(tcon->ntvfs);
                tcon->ntvfs = NULL;
        }

        if (tcon->smb2.session) {
                tcons_ctx = &tcon->smb2.session->smb2_tcons;
        } else {
                tcons_ctx = &tcon->smb_conn->smb_tcons;
        }

        idr_remove(tcons_ctx->idtree_tid, tcon->tid);
        DLIST_REMOVE(tcons_ctx->list, tcon);
        return 0;
}

/*
  find first available connection slot
*/
static struct smbsrv_tcon *smbsrv_tcon_new(struct smbsrv_connection *smb_conn,
                                           struct smbsrv_session *smb_sess,
                                           const char *share_name)
{
        TALLOC_CTX *mem_ctx;
        struct smbsrv_tcons_context *tcons_ctx;
        uint32_t handle_uint_max;
        struct smbsrv_tcon *tcon;
        NTSTATUS status;
        int i;

        if (smb_sess) {
                mem_ctx = smb_sess;
                tcons_ctx = &smb_sess->smb2_tcons;
                handle_uint_max = UINT32_MAX;
        } else {
                mem_ctx = smb_conn;
                tcons_ctx = &smb_conn->smb_tcons;
                handle_uint_max = UINT16_MAX;
        }

        tcon = talloc_zero(mem_ctx, struct smbsrv_tcon);
        if (!tcon) return NULL;
        tcon->smb_conn          = smb_conn;
        tcon->smb2.session      = smb_sess;
        tcon->share_name        = talloc_strdup(tcon, share_name);
        if (!tcon->share_name) goto failed;

        /*
         * the use -1 here, because we don't want to give away the wildcard
         * fnum used in SMBflush
         */
        status = smbsrv_init_handles(tcon, handle_uint_max - 1);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(1,("ERROR! failed to init handles: %s\n", nt_errstr(status)));
                goto failed;
        }

        i = idr_get_new_random(tcons_ctx->idtree_tid, tcon, tcons_ctx->idtree_limit);
        if (i == -1) {
                DEBUG(1,("ERROR! Out of connection structures\n"));
                goto failed;
        }
        tcon->tid = i;

        DLIST_ADD(tcons_ctx->list, tcon);
        talloc_set_destructor(tcon, smbsrv_tcon_destructor);

        /* now fill in some statistics */
        tcon->statistics.connect_time = timeval_current();

        return tcon;

failed:
        talloc_free(tcon);
        return NULL;
}

struct smbsrv_tcon *smbsrv_smb_tcon_new(struct smbsrv_connection *smb_conn, const char *share_name)
{
        return smbsrv_tcon_new(smb_conn, NULL, share_name);
}

struct smbsrv_tcon *smbsrv_smb2_tcon_new(struct smbsrv_session *smb_sess, const char *share_name)
{
        return smbsrv_tcon_new(smb_sess->smb_conn, smb_sess, share_name);
}