1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright 2016 Joyent, Inc.
  24  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  25  * Copyright (c) 2013 by Delphix. All rights reserved.
  26  */
  27 /* Copyright (c) 1990 Mentat Inc. */
  28 
  29 #include <inet/ip.h>
  30 #include <inet/tcp_impl.h>
  31 #include <sys/multidata.h>
  32 #include <sys/sunddi.h>
  33 
  34 /* Max size IP datagram is 64k - 1 */
  35 #define TCP_MSS_MAX_IPV4 (IP_MAXPACKET - (sizeof (ipha_t) + sizeof (tcpha_t)))
  36 #define TCP_MSS_MAX_IPV6 (IP_MAXPACKET - (sizeof (ip6_t) + sizeof (tcpha_t)))
  37 
  38 /* Max of the above */
  39 #define TCP_MSS_MAX             TCP_MSS_MAX_IPV4
  40 
  41 /*
  42  * Set the RFC 1948 pass phrase
  43  */
  44 /* ARGSUSED */
  45 static int
  46 tcp_set_1948phrase(netstack_t *stack,  cred_t *cr, mod_prop_info_t *pinfo,
  47     const char *ifname, const void* pr_val, uint_t flags)
  48 {
  49         if (flags & MOD_PROP_DEFAULT)
  50                 return (ENOTSUP);
  51 
  52         /*
  53          * Basically, value contains a new pass phrase.  Pass it along!
  54          */
  55         tcp_iss_key_init((uint8_t *)pr_val, strlen(pr_val),
  56             stack->netstack_tcp);
  57         return (0);
  58 }
  59 
  60 /*
  61  * returns the current list of listener limit configuration.
  62  */
  63 /* ARGSUSED */
  64 static int
  65 tcp_listener_conf_get(netstack_t *stack, mod_prop_info_t *pinfo,
  66     const char *ifname, void *val, uint_t psize, uint_t flags)
  67 {
  68         tcp_stack_t     *tcps = stack->netstack_tcp;
  69         tcp_listener_t  *tl;
  70         char            *pval = val;
  71         size_t          nbytes = 0, tbytes = 0;
  72         uint_t          size;
  73         int             err = 0;
  74 
  75         bzero(pval, psize);
  76         size = psize;
  77 
  78         if (flags & (MOD_PROP_DEFAULT|MOD_PROP_PERM|MOD_PROP_POSSIBLE))
  79                 return (0);
  80 
  81         mutex_enter(&tcps->tcps_listener_conf_lock);
  82         for (tl = list_head(&tcps->tcps_listener_conf); tl != NULL;
  83             tl = list_next(&tcps->tcps_listener_conf, tl)) {
  84                 if (psize == size)
  85                         nbytes = snprintf(pval, size, "%d:%d",  tl->tl_port,
  86                             tl->tl_ratio);
  87                 else
  88                         nbytes = snprintf(pval, size, ",%d:%d",  tl->tl_port,
  89                             tl->tl_ratio);
  90                 size -= nbytes;
  91                 pval += nbytes;
  92                 tbytes += nbytes;
  93                 if (tbytes >= psize) {
  94                         /* Buffer overflow, stop copying information */
  95                         err = ENOBUFS;
  96                         break;
  97                 }
  98         }
  99 
 100         mutex_exit(&tcps->tcps_listener_conf_lock);
 101         return (err);
 102 }
 103 
 104 /*
 105  * add a new listener limit configuration.
 106  */
 107 /* ARGSUSED */
 108 static int
 109 tcp_listener_conf_add(netstack_t *stack, cred_t *cr, mod_prop_info_t *pinfo,
 110     const char *ifname, const void* pval, uint_t flags)
 111 {
 112         tcp_listener_t  *new_tl;
 113         tcp_listener_t  *tl;
 114         long            lport;
 115         long            ratio;
 116         char            *colon;
 117         tcp_stack_t     *tcps = stack->netstack_tcp;
 118 
 119         if (flags & MOD_PROP_DEFAULT)
 120                 return (ENOTSUP);
 121 
 122         if (ddi_strtol(pval, &colon, 10, &lport) != 0 || lport <= 0 ||
 123             lport > USHRT_MAX || *colon != ':') {
 124                 return (EINVAL);
 125         }
 126         if (ddi_strtol(colon + 1, NULL, 10, &ratio) != 0 || ratio <= 0)
 127                 return (EINVAL);
 128 
 129         mutex_enter(&tcps->tcps_listener_conf_lock);
 130         for (tl = list_head(&tcps->tcps_listener_conf); tl != NULL;
 131             tl = list_next(&tcps->tcps_listener_conf, tl)) {
 132                 /* There is an existing entry, so update its ratio value. */
 133                 if (tl->tl_port == lport) {
 134                         tl->tl_ratio = ratio;
 135                         mutex_exit(&tcps->tcps_listener_conf_lock);
 136                         return (0);
 137                 }
 138         }
 139 
 140         if ((new_tl = kmem_alloc(sizeof (tcp_listener_t), KM_NOSLEEP)) ==
 141             NULL) {
 142                 mutex_exit(&tcps->tcps_listener_conf_lock);
 143                 return (ENOMEM);
 144         }
 145 
 146         new_tl->tl_port = lport;
 147         new_tl->tl_ratio = ratio;
 148         list_insert_tail(&tcps->tcps_listener_conf, new_tl);
 149         mutex_exit(&tcps->tcps_listener_conf_lock);
 150         return (0);
 151 }
 152 
 153 /*
 154  * remove a listener limit configuration.
 155  */
 156 /* ARGSUSED */
 157 static int
 158 tcp_listener_conf_del(netstack_t *stack, cred_t *cr, mod_prop_info_t *pinfo,
 159     const char *ifname, const void* pval, uint_t flags)
 160 {
 161         tcp_listener_t  *tl;
 162         long            lport;
 163         tcp_stack_t     *tcps = stack->netstack_tcp;
 164 
 165         if (flags & MOD_PROP_DEFAULT)
 166                 return (ENOTSUP);
 167 
 168         if (ddi_strtol(pval, NULL, 10, &lport) != 0 || lport <= 0 ||
 169             lport > USHRT_MAX) {
 170                 return (EINVAL);
 171         }
 172         mutex_enter(&tcps->tcps_listener_conf_lock);
 173         for (tl = list_head(&tcps->tcps_listener_conf); tl != NULL;
 174             tl = list_next(&tcps->tcps_listener_conf, tl)) {
 175                 if (tl->tl_port == lport) {
 176                         list_remove(&tcps->tcps_listener_conf, tl);
 177                         mutex_exit(&tcps->tcps_listener_conf_lock);
 178                         kmem_free(tl, sizeof (tcp_listener_t));
 179                         return (0);
 180                 }
 181         }
 182         mutex_exit(&tcps->tcps_listener_conf_lock);
 183         return (ESRCH);
 184 }
 185 
 186 static int
 187 tcp_set_buf_prop(netstack_t *stack, cred_t *cr, mod_prop_info_t *pinfo,
 188     const char *ifname, const void *pval, uint_t flags)
 189 {
 190         return (mod_set_buf_prop(stack->netstack_tcp->tcps_propinfo_tbl, stack,
 191             cr, pinfo, ifname, pval, flags));
 192 }
 193 
 194 static int
 195 tcp_get_buf_prop(netstack_t *stack, mod_prop_info_t *pinfo, const char *ifname,
 196     void *val, uint_t psize, uint_t flags)
 197 {
 198         return (mod_get_buf_prop(stack->netstack_tcp->tcps_propinfo_tbl, stack,
 199             pinfo, ifname, val, psize, flags));
 200 }
 201 
 202 /*
 203  * Special checkers for smallest/largest anonymous port so they don't
 204  * ever happen to be (largest < smallest).
 205  */
 206 /* ARGSUSED */
 207 static int
 208 tcp_smallest_anon_set(netstack_t *stack, cred_t *cr, mod_prop_info_t *pinfo,
 209     const char *ifname, const void *pval, uint_t flags)
 210 {
 211         unsigned long new_value;
 212         tcp_stack_t *tcps = stack->netstack_tcp;
 213         int err;
 214 
 215         if ((err = mod_uint32_value(pval, pinfo, flags, &new_value)) != 0)
 216                 return (err);
 217         /* mod_uint32_value() + pinfo guarantees we're in TCP port range. */
 218         if ((uint32_t)new_value > tcps->tcps_largest_anon_port)
 219                 return (ERANGE);
 220         pinfo->prop_cur_uval = (uint32_t)new_value;
 221         return (0);
 222 }
 223 
 224 /* ARGSUSED */
 225 static int
 226 tcp_largest_anon_set(netstack_t *stack, cred_t *cr, mod_prop_info_t *pinfo,
 227     const char *ifname, const void *pval, uint_t flags)
 228 {
 229         unsigned long new_value;
 230         tcp_stack_t *tcps = stack->netstack_tcp;
 231         int err;
 232 
 233         if ((err = mod_uint32_value(pval, pinfo, flags, &new_value)) != 0)
 234                 return (err);
 235         /* mod_uint32_value() + pinfo guarantees we're in TCP port range. */
 236         if ((uint32_t)new_value < tcps->tcps_smallest_anon_port)
 237                 return (ERANGE);
 238         pinfo->prop_cur_uval = (uint32_t)new_value;
 239         return (0);
 240 }
 241 
 242 /*
 243  * All of these are alterable, within the min/max values given, at run time.
 244  *
 245  * Note: All those tunables which do not start with "_" are Committed and
 246  * therefore are public. See PSARC 2010/080.
 247  */
 248 mod_prop_info_t tcp_propinfo_tbl[] = {
 249         /* tunable - 0 */
 250         { "_time_wait_interval", MOD_PROTO_TCP,
 251             mod_set_uint32, mod_get_uint32,
 252             {1*SECONDS, TCP_TIME_WAIT_MAX, 1*MINUTES}, {1*MINUTES} },
 253 
 254         { "_conn_req_max_q", MOD_PROTO_TCP,
 255             mod_set_uint32, mod_get_uint32,
 256             {1, UINT32_MAX, 128}, {128} },
 257 
 258         { "_conn_req_max_q0", MOD_PROTO_TCP,
 259             mod_set_uint32, mod_get_uint32,
 260             {0, UINT32_MAX, 1024}, {1024} },
 261 
 262         { "_conn_req_min", MOD_PROTO_TCP,
 263             mod_set_uint32, mod_get_uint32,
 264             {1, 1024, 1}, {1} },
 265 
 266         { "_conn_grace_period", MOD_PROTO_TCP,
 267             mod_set_uint32, mod_get_uint32,
 268             {0*MS, 20*SECONDS, 0*MS}, {0*MS} },
 269 
 270         { "_cwnd_max", MOD_PROTO_TCP,
 271             mod_set_uint32, mod_get_uint32,
 272             {128, ULP_MAX_BUF, 1024*1024}, {1024*1024} },
 273 
 274         { "_debug", MOD_PROTO_TCP,
 275             mod_set_uint32, mod_get_uint32,
 276             {0, 10, 0}, {0} },
 277 
 278         { "smallest_nonpriv_port", MOD_PROTO_TCP,
 279             mod_set_uint32, mod_get_uint32,
 280             {1024, (32*1024), 1024}, {1024} },
 281 
 282         { "_ip_abort_cinterval", MOD_PROTO_TCP,
 283             mod_set_uint32, mod_get_uint32,
 284             {1*SECONDS, UINT32_MAX, 3*MINUTES}, {3*MINUTES} },
 285 
 286         { "_ip_abort_linterval", MOD_PROTO_TCP,
 287             mod_set_uint32, mod_get_uint32,
 288             {1*SECONDS, UINT32_MAX, 3*MINUTES}, {3*MINUTES} },
 289 
 290         /* tunable - 10 */
 291         { "_ip_abort_interval", MOD_PROTO_TCP,
 292             mod_set_uint32, mod_get_uint32,
 293             {500*MS, UINT32_MAX, 5*MINUTES}, {5*MINUTES} },
 294 
 295         { "_ip_notify_cinterval", MOD_PROTO_TCP,
 296             mod_set_uint32, mod_get_uint32,
 297             {1*SECONDS, UINT32_MAX, 10*SECONDS},
 298             {10*SECONDS} },
 299 
 300         { "_ip_notify_interval", MOD_PROTO_TCP,
 301             mod_set_uint32, mod_get_uint32,
 302             {500*MS, UINT32_MAX, 10*SECONDS}, {10*SECONDS} },
 303 
 304         { "_ipv4_ttl", MOD_PROTO_TCP,
 305             mod_set_uint32, mod_get_uint32,
 306             {1, 255, 64}, {64} },
 307 
 308         { "_keepalive_interval", MOD_PROTO_TCP,
 309             mod_set_uint32, mod_get_uint32,
 310             {1*SECONDS, 10*DAYS, 2*HOURS}, {2*HOURS} },
 311 
 312         { "_maxpsz_multiplier", MOD_PROTO_TCP,
 313             mod_set_uint32, mod_get_uint32,
 314             {0, 100, 10}, {10} },
 315 
 316         { "_mss_def_ipv4", MOD_PROTO_TCP,
 317             mod_set_uint32, mod_get_uint32,
 318             {1, TCP_MSS_MAX_IPV4, 536}, {536} },
 319 
 320         { "_mss_max_ipv4", MOD_PROTO_TCP,
 321             mod_set_uint32, mod_get_uint32,
 322             {1, TCP_MSS_MAX_IPV4, TCP_MSS_MAX_IPV4},
 323             {TCP_MSS_MAX_IPV4} },
 324 
 325         { "_mss_min", MOD_PROTO_TCP,
 326             mod_set_uint32, mod_get_uint32,
 327             {1, TCP_MSS_MAX, 108}, {108} },
 328 
 329         { "_naglim_def", MOD_PROTO_TCP,
 330             mod_set_uint32, mod_get_uint32,
 331             {1, (64*1024)-1, (4*1024)-1}, {(4*1024)-1} },
 332 
 333         /* tunable - 20 */
 334         { "_rexmit_interval_initial", MOD_PROTO_TCP,
 335             mod_set_uint32, mod_get_uint32,
 336             {1*MS, 20*SECONDS, 1*SECONDS}, {1*SECONDS} },
 337 
 338         { "_rexmit_interval_max", MOD_PROTO_TCP,
 339             mod_set_uint32, mod_get_uint32,
 340             {1*MS, 2*HOURS, 60*SECONDS}, {60*SECONDS} },
 341 
 342         { "_rexmit_interval_min", MOD_PROTO_TCP,
 343             mod_set_uint32, mod_get_uint32,
 344             {1*MS, 2*HOURS, 400*MS}, {400*MS} },
 345 
 346         { "_deferred_ack_interval", MOD_PROTO_TCP,
 347             mod_set_uint32, mod_get_uint32,
 348             {1*MS, 1*MINUTES, 100*MS}, {100*MS} },
 349 
 350         { "_snd_lowat_fraction", MOD_PROTO_TCP,
 351             mod_set_uint32, mod_get_uint32,
 352             {0, 16, 10}, {10} },
 353 
 354         { "_dupack_fast_retransmit", MOD_PROTO_TCP,
 355             mod_set_uint32, mod_get_uint32,
 356             {1, 10000, 3}, {3} },
 357 
 358         { "_ignore_path_mtu", MOD_PROTO_TCP,
 359             mod_set_boolean, mod_get_boolean,
 360             {B_FALSE}, {B_FALSE} },
 361 
 362         { "smallest_anon_port", MOD_PROTO_TCP,
 363             tcp_smallest_anon_set, mod_get_uint32,
 364             {1024, ULP_MAX_PORT, 32*1024}, {32*1024} },
 365 
 366         { "largest_anon_port", MOD_PROTO_TCP,
 367             tcp_largest_anon_set, mod_get_uint32,
 368             {1024, ULP_MAX_PORT, ULP_MAX_PORT},
 369             {ULP_MAX_PORT} },
 370 
 371         { "send_buf", MOD_PROTO_TCP,
 372             tcp_set_buf_prop, tcp_get_buf_prop,
 373             {TCP_XMIT_LOWATER, ULP_MAX_BUF, TCP_XMIT_HIWATER},
 374             {TCP_XMIT_HIWATER} },
 375 
 376         /* tunable - 30 */
 377         { "_xmit_lowat", MOD_PROTO_TCP,
 378             mod_set_uint32, mod_get_uint32,
 379             {TCP_XMIT_LOWATER, ULP_MAX_BUF, TCP_XMIT_LOWATER},
 380             {TCP_XMIT_LOWATER} },
 381 
 382         { "recv_buf", MOD_PROTO_TCP,
 383             tcp_set_buf_prop, tcp_get_buf_prop,
 384             {TCP_RECV_LOWATER, ULP_MAX_BUF, TCP_RECV_HIWATER},
 385             {TCP_RECV_HIWATER} },
 386 
 387         { "_recv_hiwat_minmss", MOD_PROTO_TCP,
 388             mod_set_uint32, mod_get_uint32,
 389             {1, 65536, 4}, {4} },
 390 
 391         { "_fin_wait_2_flush_interval", MOD_PROTO_TCP,
 392             mod_set_uint32, mod_get_uint32,
 393             {1*SECONDS, 2*HOURS, 60*SECONDS},
 394             {60*SECONDS} },
 395 
 396         { "max_buf", MOD_PROTO_TCP,
 397             mod_set_uint32, mod_get_uint32,
 398             {8192, ULP_MAX_BUF, 1024*1024}, {1024*1024} },
 399 
 400         { "_strong_iss", MOD_PROTO_TCP,
 401             mod_set_uint32, mod_get_uint32,
 402             {0, 2, 2}, {2} },
 403 
 404         { "_rtt_updates", MOD_PROTO_TCP,
 405             mod_set_uint32, mod_get_uint32,
 406             {0, 65536, 20}, {20} },
 407 
 408         { "_wscale_always", MOD_PROTO_TCP,
 409             mod_set_boolean, mod_get_boolean,
 410             {B_TRUE}, {B_TRUE} },
 411 
 412         { "_tstamp_always", MOD_PROTO_TCP,
 413             mod_set_boolean, mod_get_boolean,
 414             {B_FALSE}, {B_FALSE} },
 415 
 416         { "_tstamp_if_wscale", MOD_PROTO_TCP,
 417             mod_set_boolean, mod_get_boolean,
 418             {B_TRUE}, {B_TRUE} },
 419 
 420         /* tunable - 40 */
 421         { "_rexmit_interval_extra", MOD_PROTO_TCP,
 422             mod_set_uint32, mod_get_uint32,
 423             {0*MS, 2*HOURS, 0*MS}, {0*MS} },
 424 
 425         { "_deferred_acks_max", MOD_PROTO_TCP,
 426             mod_set_uint32, mod_get_uint32,
 427             {0, 16, 2}, {2} },
 428 
 429         { "_slow_start_after_idle", MOD_PROTO_TCP,
 430             mod_set_uint32, mod_get_uint32,
 431             {0, 16384, 0}, {0} },
 432 
 433         { "_slow_start_initial", MOD_PROTO_TCP,
 434             mod_set_uint32, mod_get_uint32,
 435             {0, 16, 0}, {0} },
 436 
 437         { "sack", MOD_PROTO_TCP,
 438             mod_set_uint32, mod_get_uint32,
 439             {0, 2, 2}, {2} },
 440 
 441         { "_ipv6_hoplimit", MOD_PROTO_TCP,
 442             mod_set_uint32, mod_get_uint32,
 443             {0, IPV6_MAX_HOPS, IPV6_DEFAULT_HOPS},
 444             {IPV6_DEFAULT_HOPS} },
 445 
 446         { "_mss_def_ipv6", MOD_PROTO_TCP,
 447             mod_set_uint32, mod_get_uint32,
 448             {1, TCP_MSS_MAX_IPV6, 1220}, {1220} },
 449 
 450         { "_mss_max_ipv6", MOD_PROTO_TCP,
 451             mod_set_uint32, mod_get_uint32,
 452             {1, TCP_MSS_MAX_IPV6, TCP_MSS_MAX_IPV6},
 453             {TCP_MSS_MAX_IPV6} },
 454 
 455         { "_rev_src_routes", MOD_PROTO_TCP,
 456             mod_set_boolean, mod_get_boolean,
 457             {B_FALSE}, {B_FALSE} },
 458 
 459         { "_local_dack_interval", MOD_PROTO_TCP,
 460             mod_set_uint32, mod_get_uint32,
 461             {10*MS, 500*MS, 50*MS}, {50*MS} },
 462 
 463         /* tunable - 50 */
 464         { "_local_dacks_max", MOD_PROTO_TCP,
 465             mod_set_uint32, mod_get_uint32,
 466             {0, 16, 8}, {8} },
 467 
 468         { "ecn", MOD_PROTO_TCP,
 469             mod_set_uint32, mod_get_uint32,
 470             {0, 2, 1}, {1} },
 471 
 472         { "_rst_sent_rate_enabled", MOD_PROTO_TCP,
 473             mod_set_boolean, mod_get_boolean,
 474             {B_TRUE}, {B_TRUE} },
 475 
 476         { "_rst_sent_rate", MOD_PROTO_TCP,
 477             mod_set_uint32, mod_get_uint32,
 478             {0, UINT32_MAX, 40}, {40} },
 479 
 480         { "_push_timer_interval", MOD_PROTO_TCP,
 481             mod_set_uint32, mod_get_uint32,
 482             {0, 100*MS, 50*MS}, {50*MS} },
 483 
 484         { "_use_smss_as_mss_opt", MOD_PROTO_TCP,
 485             mod_set_boolean, mod_get_boolean,
 486             {B_FALSE}, {B_FALSE} },
 487 
 488         { "_keepalive_abort_interval", MOD_PROTO_TCP,
 489             mod_set_uint32, mod_get_uint32,
 490             {0, UINT32_MAX, 8*MINUTES}, {8*MINUTES} },
 491 
 492         /*
 493          * tcp_wroff_xtra is the extra space in front of TCP/IP header for link
 494          * layer header.  It has to be a multiple of 8.
 495          */
 496         { "_wroff_xtra", MOD_PROTO_TCP,
 497             mod_set_aligned, mod_get_uint32,
 498             {0, 256, 32}, {32} },
 499 
 500         { "_dev_flow_ctl", MOD_PROTO_TCP,
 501             mod_set_boolean, mod_get_boolean,
 502             {B_FALSE}, {B_FALSE} },
 503 
 504         { "_reass_timeout", MOD_PROTO_TCP,
 505             mod_set_uint32, mod_get_uint32,
 506             {0, UINT32_MAX, 100*SECONDS}, {100*SECONDS} },
 507 
 508         /* tunable - 60 */
 509         { "extra_priv_ports", MOD_PROTO_TCP,
 510             mod_set_extra_privports, mod_get_extra_privports,
 511             {1, ULP_MAX_PORT, 0}, {0} },
 512 
 513         { "_1948_phrase", MOD_PROTO_TCP,
 514             tcp_set_1948phrase, NULL, {0}, {0} },
 515 
 516         { "_listener_limit_conf", MOD_PROTO_TCP,
 517             NULL, tcp_listener_conf_get, {0}, {0} },
 518 
 519         { "_listener_limit_conf_add", MOD_PROTO_TCP,
 520             tcp_listener_conf_add, NULL, {0}, {0} },
 521 
 522         { "_listener_limit_conf_del", MOD_PROTO_TCP,
 523             tcp_listener_conf_del, NULL, {0}, {0} },
 524 
 525         { "_iss_incr", MOD_PROTO_TCP,
 526             mod_set_uint32, mod_get_uint32,
 527             {1, ISS_INCR, ISS_INCR},
 528             {ISS_INCR} },
 529 
 530         { "?", MOD_PROTO_TCP, NULL, mod_get_allprop, {0}, {0} },
 531 
 532         { NULL, 0, NULL, NULL, {0}, {0} }
 533 };
 534 
 535 int tcp_propinfo_count = A_CNT(tcp_propinfo_tbl);