source: trunk/server/source3/smbd/conn.c@ 992

/*
   Unix SMB/CIFS implementation.
   Manage connections_struct structures
   Copyright (C) Andrew Tridgell 1998
   Copyright (C) Alexander Bokovoy 2002
   Copyright (C) Jeremy Allison 2010

   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 "smbd/smbd.h"
#include "smbd/globals.h"
#include "rpc_server/rpc_ncacn_np.h"
#include "lib/util/bitmap.h"

/* The connections bitmap is expanded in increments of BITMAP_BLOCK_SZ. The
 * maximum size of the bitmap is the largest positive integer, but you will hit
 * the "max connections" limit, looong before that.
 */

#define BITMAP_BLOCK_SZ 128

/****************************************************************************
 Init the conn structures.
****************************************************************************/

void conn_init(struct smbd_server_connection *sconn)
{
        sconn->smb1.tcons.Connections = NULL;
        sconn->smb1.tcons.bmap = bitmap_talloc(sconn, BITMAP_BLOCK_SZ);
}

/****************************************************************************
 Return the number of open connections.
****************************************************************************/

int conn_num_open(struct smbd_server_connection *sconn)
{
        return sconn->num_tcons_open;
}

/****************************************************************************
 Check if a snum is in use.
****************************************************************************/

bool conn_snum_used(int snum)
{
        struct smbd_server_connection *sconn = smbd_server_conn;

        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *ptcon;

                        for (ptcon = sess->tcons.list; ptcon; ptcon = ptcon->next) {
                                if (ptcon->compat_conn &&
                                                ptcon->compat_conn->params &&
                                                (ptcon->compat_conn->params->service == snum)) {
                                        return true;
                                }
                        }
                }
        } else {
                /* SMB1 */
                connection_struct *conn;
                for (conn=sconn->smb1.tcons.Connections;conn;conn=conn->next) {
                        if (conn->params->service == snum) {
                                return true;
                        }
                }
        }
        return false;
}

/****************************************************************************
 Find a conn given a cnum.
****************************************************************************/

connection_struct *conn_find(struct smbd_server_connection *sconn,unsigned cnum)
{
        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *ptcon;

                        for (ptcon = sess->tcons.list; ptcon; ptcon = ptcon->next) {
                                if (ptcon->compat_conn &&
                                                ptcon->compat_conn->cnum == cnum) {
                                        return ptcon->compat_conn;
                                }
                        }
                }
        } else {
                /* SMB1 */
                int count=0;
                connection_struct *conn;
                for (conn=sconn->smb1.tcons.Connections;conn;conn=conn->next,count++) {
                        if (conn->cnum == cnum) {
                                if (count > 10) {
                                        DLIST_PROMOTE(sconn->smb1.tcons.Connections,
                                                conn);
                                }
                                return conn;
                        }
                }
        }

        return NULL;
}

/****************************************************************************
 Find first available connection slot, starting from a random position.
 The randomisation stops problems with the server dieing and clients
 thinking the server is still available.
****************************************************************************/

connection_struct *conn_new(struct smbd_server_connection *sconn)
{
        connection_struct *conn;
        int i;
        int find_offset = 1;

        if (sconn->using_smb2) {
                /* SMB2 */
                if (!(conn=TALLOC_ZERO_P(NULL, connection_struct)) ||
                    !(conn->params = TALLOC_P(conn, struct share_params))) {
                        DEBUG(0,("TALLOC_ZERO() failed!\n"));
                        TALLOC_FREE(conn);
                        return NULL;
                }
                conn->sconn = sconn;
                return conn;
        }

        /* SMB1 */
find_again:
        i = bitmap_find(sconn->smb1.tcons.bmap, find_offset);

        if (i == -1) {
                /* Expand the connections bitmap. */
                int             oldsz = sconn->smb1.tcons.bmap->n;
                int             newsz = sconn->smb1.tcons.bmap->n +
                                        BITMAP_BLOCK_SZ;
                struct bitmap * nbmap;

                if (newsz <= oldsz) {
                        /* Integer wrap. */
                        DEBUG(0,("ERROR! Out of connection structures\n"));
                        return NULL;
                }

                DEBUG(4,("resizing connections bitmap from %d to %d\n",
                        oldsz, newsz));

                nbmap = bitmap_talloc(sconn, newsz);
                if (!nbmap) {
                        DEBUG(0,("ERROR! malloc fail.\n"));
                        return NULL;
                }

                bitmap_copy(nbmap, sconn->smb1.tcons.bmap);
                TALLOC_FREE(sconn->smb1.tcons.bmap);

                sconn->smb1.tcons.bmap = nbmap;
                find_offset = oldsz; /* Start next search in the new portion. */

                goto find_again;
        }

        /* The bitmap position is used below as the connection number
         * conn->cnum). This ends up as the TID field in the SMB header,
         * which is limited to 16 bits (we skip 0xffff which is the
         * NULL TID).
         */
        if (i > 65534) {
                DEBUG(0, ("Maximum connection limit reached\n"));
                return NULL;
        }

        if (!(conn=TALLOC_ZERO_P(NULL, connection_struct)) ||
            !(conn->params = TALLOC_P(conn, struct share_params))) {
                DEBUG(0,("TALLOC_ZERO() failed!\n"));
                TALLOC_FREE(conn);
                return NULL;
        }
        conn->sconn = sconn;
        conn->cnum = i;
        conn->force_group_gid = (gid_t)-1;

        bitmap_set(sconn->smb1.tcons.bmap, i);

        sconn->num_tcons_open++;

        string_set(&conn->connectpath,"");
        string_set(&conn->origpath,"");

        DLIST_ADD(sconn->smb1.tcons.Connections, conn);

        return conn;
}

/****************************************************************************
 Close all conn structures.
 Return true if any were closed.
****************************************************************************/

bool conn_close_all(struct smbd_server_connection *sconn)
{
        bool ret = false;
        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *tcon, *tc_next;

                        for (tcon = sess->tcons.list; tcon; tcon = tc_next) {
                                tc_next = tcon->next;
                                TALLOC_FREE(tcon);
                                ret = true;
                        }
                }
        } else {
                /* SMB1 */
                connection_struct *conn, *next;

                for (conn=sconn->smb1.tcons.Connections;conn;conn=next) {
                        next=conn->next;
                        set_current_service(conn, 0, True);
                        close_cnum(conn, conn->vuid);
                        ret = true;
                }
        }
        return ret;
}

/****************************************************************************
 Update last used timestamps.
****************************************************************************/

static void conn_lastused_update(struct smbd_server_connection *sconn,time_t t)
{
        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *ptcon;

                        for (ptcon = sess->tcons.list; ptcon; ptcon = ptcon->next) {
                                connection_struct *conn = ptcon->compat_conn;
                                /* Update if connection wasn't idle. */
                                if (conn && conn->lastused != conn->lastused_count) {
                                        conn->lastused = t;
                                        conn->lastused_count = t;
                                }
                        }
                }
        } else {
                /* SMB1 */
                connection_struct *conn;
                for (conn=sconn->smb1.tcons.Connections;conn;conn=conn->next) {
                        /* Update if connection wasn't idle. */
                        if (conn->lastused != conn->lastused_count) {
                                conn->lastused = t;
                                conn->lastused_count = t;
                        }
                }
        }
}

/****************************************************************************
 Idle inactive connections.
****************************************************************************/

bool conn_idle_all(struct smbd_server_connection *sconn, time_t t)
{
        int deadtime = lp_deadtime()*60;

        conn_lastused_update(sconn, t);

        if (deadtime <= 0) {
                deadtime = DEFAULT_SMBD_TIMEOUT;
        }

        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *ptcon;

                        for (ptcon = sess->tcons.list; ptcon; ptcon = ptcon->next) {
                                time_t age;
                                connection_struct *conn = ptcon->compat_conn;

                                if (conn == NULL) {
                                        continue;
                                }

                                age = t - conn->lastused;
                                /* close dirptrs on connections that are idle */
                                if (age > DPTR_IDLE_TIMEOUT) {
                                        dptr_idlecnum(conn);
                                }

                                if (conn->num_files_open > 0 || age < deadtime) {
                                        return false;
                                }
                        }
                }
        } else {
                /* SMB1 */
                connection_struct *conn;
                for (conn=sconn->smb1.tcons.Connections;conn;conn=conn->next) {
                        time_t age = t - conn->lastused;

                        /* close dirptrs on connections that are idle */
                        if (age > DPTR_IDLE_TIMEOUT) {
                                dptr_idlecnum(conn);
                        }

                        if (conn->num_files_open > 0 || age < deadtime) {
                                return false;
                        }
                }
        }

        /*
         * Check all pipes for any open handles. We cannot
         * idle with a handle open.
         */
        if (check_open_pipes()) {
                return false;
        }

        return true;
}

/****************************************************************************
 Clear a vuid out of the validity cache, and as the 'owner' of a connection.
****************************************************************************/

void conn_clear_vuid_caches(struct smbd_server_connection *sconn,uint16_t vuid)
{
        connection_struct *conn;

        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *ptcon;

                        for (ptcon = sess->tcons.list; ptcon; ptcon = ptcon->next) {
                                if (ptcon->compat_conn) {
                                        if (ptcon->compat_conn->vuid == vuid) {
                                                ptcon->compat_conn->vuid = UID_FIELD_INVALID;
                                        }
                                        conn_clear_vuid_cache(ptcon->compat_conn, vuid);
                                }
                        }
                }
        } else {
                /* SMB1 */
                for (conn=sconn->smb1.tcons.Connections;conn;conn=conn->next) {
                        if (conn->vuid == vuid) {
                                conn->vuid = UID_FIELD_INVALID;
                        }
                        conn_clear_vuid_cache(conn, vuid);
                }
        }
}

/****************************************************************************
 Free a conn structure - internal part.
****************************************************************************/

static void conn_free_internal(connection_struct *conn)
{
        vfs_handle_struct *handle = NULL, *thandle = NULL;
        struct trans_state *state = NULL;

        /* Free vfs_connection_struct */
        handle = conn->vfs_handles;
        while(handle) {
                thandle = handle->next;
                DLIST_REMOVE(conn->vfs_handles, handle);
                if (handle->free_data)
                        handle->free_data(&handle->data);
                handle = thandle;
        }

        /* Free any pending transactions stored on this conn. */
        for (state = conn->pending_trans; state; state = state->next) {
                /* state->setup is a talloc child of state. */
                SAFE_FREE(state->param);
                SAFE_FREE(state->data);
        }

        free_namearray(conn->veto_list);
        free_namearray(conn->hide_list);
        free_namearray(conn->veto_oplock_list);
        free_namearray(conn->aio_write_behind_list);

        string_free(&conn->connectpath);
        string_free(&conn->origpath);

        ZERO_STRUCTP(conn);
        talloc_destroy(conn);
}

/****************************************************************************
 Free a conn structure.
****************************************************************************/

void conn_free(connection_struct *conn)
{
        if (conn->sconn == NULL) {
                conn_free_internal(conn);
                return;
        }

        if (conn->sconn->using_smb2) {
                /* SMB2 */
                conn_free_internal(conn);
                return;
        }

        /* SMB1 */
        DLIST_REMOVE(conn->sconn->smb1.tcons.Connections, conn);

        if (conn->sconn->smb1.tcons.bmap != NULL) {
                /*
                 * Can be NULL for fake connections created by
                 * create_conn_struct()
                 */
                bitmap_clear(conn->sconn->smb1.tcons.bmap, conn->cnum);
        }

        SMB_ASSERT(conn->sconn->num_tcons_open > 0);
        conn->sconn->num_tcons_open--;

        conn_free_internal(conn);
}

/****************************************************************************
 Receive a smbcontrol message to forcibly unmount a share.
 The message contains just a share name and all instances of that
 share are unmounted.
 The special sharename '*' forces unmount of all shares.
****************************************************************************/

void msg_force_tdis(struct messaging_context *msg,
                    void *private_data,
                    uint32_t msg_type,
                    struct server_id server_id,
                    DATA_BLOB *data)
{
        struct smbd_server_connection *sconn;
        connection_struct *conn, *next;
        fstring sharename;

        sconn = msg_ctx_to_sconn(msg);
        if (sconn == NULL) {
                DEBUG(1, ("could not find sconn\n"));
                return;
        }

        fstrcpy(sharename, (const char *)data->data);

        if (strcmp(sharename, "*") == 0) {
                DEBUG(1,("Forcing close of all shares\n"));
                conn_close_all(sconn);
                goto done;
        }

        if (sconn->using_smb2) {
                /* SMB2 */
                struct smbd_smb2_session *sess;
                for (sess = sconn->smb2.sessions.list; sess; sess = sess->next) {
                        struct smbd_smb2_tcon *tcon, *tc_next;

                        for (tcon = sess->tcons.list; tcon; tcon = tc_next) {
                                tc_next = tcon->next;
                                if (tcon->compat_conn &&
                                                strequal(lp_servicename(SNUM(tcon->compat_conn)),
                                                                sharename)) {
                                        DEBUG(1,("Forcing close of share %s cnum=%d\n",
                                                sharename, tcon->compat_conn->cnum));
                                        TALLOC_FREE(tcon);
                                }
                        }
                }
        } else {
                /* SMB1 */
                for (conn=sconn->smb1.tcons.Connections;conn;conn=next) {
                        next=conn->next;
                        if (strequal(lp_servicename(SNUM(conn)), sharename)) {
                                DEBUG(1,("Forcing close of share %s cnum=%d\n",
                                        sharename, conn->cnum));
                                close_cnum(conn, (uint16)-1);
                        }
                }
        }

 done:

        change_to_root_user();
        reload_services(msg, -1, true);
}