net/rds/tcp.c

   1 /*
   2  * Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/slab.h>
  35 #include <linux/in.h>
  36 #include <linux/module.h>
  37 #include <net/tcp.h>
  38 #include <net/net_namespace.h>
  39 #include <net/netns/generic.h>
  40 #include <net/addrconf.h>
  41
  42 #include "rds.h"
  43 #include "tcp.h"
  44
  45 /* only for info exporting */
  46 static DEFINE_SPINLOCK(rds_tcp_tc_list_lock);
  47 static LIST_HEAD(rds_tcp_tc_list);
  48
  49 /* rds_tcp_tc_count counts only IPv4 connections.
  50  * rds6_tcp_tc_count counts both IPv4 and IPv6 connections.
  51  */
  52 static unsigned int rds_tcp_tc_count;
  53 #if IS_ENABLED(CONFIG_IPV6)
  54 static unsigned int rds6_tcp_tc_count;
  55 #endif
  56
  57 /* Track rds_tcp_connection structs so they can be cleaned up */
  58 static DEFINE_SPINLOCK(rds_tcp_conn_lock);
  59 static LIST_HEAD(rds_tcp_conn_list);
  60 static atomic_t rds_tcp_unloading = ATOMIC_INIT(0);
  61
  62 static struct kmem_cache *rds_tcp_conn_slab;
  63
  64 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
  65                                  void *buffer, size_t *lenp, loff_t *fpos);
  66
  67 static int rds_tcp_min_sndbuf = SOCK_MIN_SNDBUF;
  68 static int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;
  69
  70 static struct ctl_table rds_tcp_sysctl_table[] = {
  71 #define RDS_TCP_SNDBUF  0
  72         {
  73                 .procname       = "rds_tcp_sndbuf",
  74                 /* data is per-net pointer */
  75                 .maxlen         = sizeof(int),
  76                 .mode           = 0644,
  77                 .proc_handler   = rds_tcp_skbuf_handler,
  78                 .extra1         = &rds_tcp_min_sndbuf,
  79         },
  80 #define RDS_TCP_RCVBUF  1
  81         {
  82                 .procname       = "rds_tcp_rcvbuf",
  83                 /* data is per-net pointer */
  84                 .maxlen         = sizeof(int),
  85                 .mode           = 0644,
  86                 .proc_handler   = rds_tcp_skbuf_handler,
  87                 .extra1         = &rds_tcp_min_rcvbuf,
  88         },
  89         { }
  90 };
  91
  92 u32 rds_tcp_write_seq(struct rds_tcp_connection *tc)
  93 {
  94         /* seq# of the last byte of data in tcp send buffer */
  95         return tcp_sk(tc->t_sock->sk)->write_seq;
  96 }
  97
  98 u32 rds_tcp_snd_una(struct rds_tcp_connection *tc)
  99 {
 100         return tcp_sk(tc->t_sock->sk)->snd_una;
 101 }
 102
 103 void rds_tcp_restore_callbacks(struct socket *sock,
 104                                struct rds_tcp_connection *tc)
 105 {
 106         rdsdebug("restoring sock %p callbacks from tc %p\n", sock, tc);
 107         write_lock_bh(&sock->sk->sk_callback_lock);
 108
 109         /* done under the callback_lock to serialize with write_space */
 110         spin_lock(&rds_tcp_tc_list_lock);
 111         list_del_init(&tc->t_list_item);
 112 #if IS_ENABLED(CONFIG_IPV6)
 113         rds6_tcp_tc_count--;
 114 #endif
 115         if (!tc->t_cpath->cp_conn->c_isv6)
 116                 rds_tcp_tc_count--;
 117         spin_unlock(&rds_tcp_tc_list_lock);
 118
 119         tc->t_sock = NULL;
 120
 121         sock->sk->sk_write_space = tc->t_orig_write_space;
 122         sock->sk->sk_data_ready = tc->t_orig_data_ready;
 123         sock->sk->sk_state_change = tc->t_orig_state_change;
 124         sock->sk->sk_user_data = NULL;
 125
 126         write_unlock_bh(&sock->sk->sk_callback_lock);
 127 }
 128
 129 /*
 130  * rds_tcp_reset_callbacks() switches the to the new sock and
 131  * returns the existing tc->t_sock.
 132  *
 133  * The only functions that set tc->t_sock are rds_tcp_set_callbacks
 134  * and rds_tcp_reset_callbacks.  Send and receive trust that
 135  * it is set.  The absence of RDS_CONN_UP bit protects those paths
 136  * from being called while it isn't set.
 137  */
 138 void rds_tcp_reset_callbacks(struct socket *sock,
 139                              struct rds_conn_path *cp)
 140 {
 141         struct rds_tcp_connection *tc = cp->cp_transport_data;
 142         struct socket *osock = tc->t_sock;
 143
 144         if (!osock)
 145                 goto newsock;
 146
 147         /* Need to resolve a duelling SYN between peers.
 148          * We have an outstanding SYN to this peer, which may
 149          * potentially have transitioned to the RDS_CONN_UP state,
 150          * so we must quiesce any send threads before resetting
 151          * cp_transport_data. We quiesce these threads by setting
 152          * cp_state to something other than RDS_CONN_UP, and then
 153          * waiting for any existing threads in rds_send_xmit to
 154          * complete release_in_xmit(). (Subsequent threads entering
 155          * rds_send_xmit() will bail on !rds_conn_up().
 156          *
 157          * However an incoming syn-ack at this point would end up
 158          * marking the conn as RDS_CONN_UP, and would again permit
 159          * rds_send_xmi() threads through, so ideally we would
 160          * synchronize on RDS_CONN_UP after lock_sock(), but cannot
 161          * do that: waiting on !RDS_IN_XMIT after lock_sock() may
 162          * end up deadlocking with tcp_sendmsg(), and the RDS_IN_XMIT
 163          * would not get set. As a result, we set c_state to
 164          * RDS_CONN_RESETTTING, to ensure that rds_tcp_state_change
 165          * cannot mark rds_conn_path_up() in the window before lock_sock()
 166          */
 167         atomic_set(&cp->cp_state, RDS_CONN_RESETTING);
 168         wait_event(cp->cp_waitq, !test_bit(RDS_IN_XMIT, &cp->cp_flags));
 169         lock_sock(osock->sk);
 170         /* reset receive side state for rds_tcp_data_recv() for osock  */
 171         cancel_delayed_work_sync(&cp->cp_send_w);
 172         cancel_delayed_work_sync(&cp->cp_recv_w);
 173         if (tc->t_tinc) {
 174                 rds_inc_put(&tc->t_tinc->ti_inc);
 175                 tc->t_tinc = NULL;
 176         }
 177         tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 178         tc->t_tinc_data_rem = 0;
 179         rds_tcp_restore_callbacks(osock, tc);
 180         release_sock(osock->sk);
 181         sock_release(osock);
 182 newsock:
 183         rds_send_path_reset(cp);
 184         lock_sock(sock->sk);
 185         rds_tcp_set_callbacks(sock, cp);
 186         release_sock(sock->sk);
 187 }
 188
 189 /* Add tc to rds_tcp_tc_list and set tc->t_sock. See comments
 190  * above rds_tcp_reset_callbacks for notes about synchronization
 191  * with data path
 192  */
 193 void rds_tcp_set_callbacks(struct socket *sock, struct rds_conn_path *cp)
 194 {
 195         struct rds_tcp_connection *tc = cp->cp_transport_data;
 196
 197         rdsdebug("setting sock %p callbacks to tc %p\n", sock, tc);
 198         write_lock_bh(&sock->sk->sk_callback_lock);
 199
 200         /* done under the callback_lock to serialize with write_space */
 201         spin_lock(&rds_tcp_tc_list_lock);
 202         list_add_tail(&tc->t_list_item, &rds_tcp_tc_list);
 203 #if IS_ENABLED(CONFIG_IPV6)
 204         rds6_tcp_tc_count++;
 205 #endif
 206         if (!tc->t_cpath->cp_conn->c_isv6)
 207                 rds_tcp_tc_count++;
 208         spin_unlock(&rds_tcp_tc_list_lock);
 209
 210         /* accepted sockets need our listen data ready undone */
 211         if (sock->sk->sk_data_ready == rds_tcp_listen_data_ready)
 212                 sock->sk->sk_data_ready = sock->sk->sk_user_data;
 213
 214         tc->t_sock = sock;
 215         tc->t_cpath = cp;
 216         tc->t_orig_data_ready = sock->sk->sk_data_ready;
 217         tc->t_orig_write_space = sock->sk->sk_write_space;
 218         tc->t_orig_state_change = sock->sk->sk_state_change;
 219
 220         sock->sk->sk_user_data = cp;
 221         sock->sk->sk_data_ready = rds_tcp_data_ready;
 222         sock->sk->sk_write_space = rds_tcp_write_space;
 223         sock->sk->sk_state_change = rds_tcp_state_change;
 224
 225         write_unlock_bh(&sock->sk->sk_callback_lock);
 226 }
 227
 228 /* Handle RDS_INFO_TCP_SOCKETS socket option.  It only returns IPv4
 229  * connections for backward compatibility.
 230  */
 231 static void rds_tcp_tc_info(struct socket *rds_sock, unsigned int len,
 232                             struct rds_info_iterator *iter,
 233                             struct rds_info_lengths *lens)
 234 {
 235         struct rds_info_tcp_socket tsinfo;
 236         struct rds_tcp_connection *tc;
 237         unsigned long flags;
 238
 239         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
 240
 241         if (len / sizeof(tsinfo) < rds_tcp_tc_count)
 242                 goto out;
 243
 244         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
 245                 struct inet_sock *inet = inet_sk(tc->t_sock->sk);
 246
 247                 if (tc->t_cpath->cp_conn->c_isv6)
 248                         continue;
 249
 250                 tsinfo.local_addr = inet->inet_saddr;
 251                 tsinfo.local_port = inet->inet_sport;
 252                 tsinfo.peer_addr = inet->inet_daddr;
 253                 tsinfo.peer_port = inet->inet_dport;
 254
 255                 tsinfo.hdr_rem = tc->t_tinc_hdr_rem;
 256                 tsinfo.data_rem = tc->t_tinc_data_rem;
 257                 tsinfo.last_sent_nxt = tc->t_last_sent_nxt;
 258                 tsinfo.last_expected_una = tc->t_last_expected_una;
 259                 tsinfo.last_seen_una = tc->t_last_seen_una;
 260                 tsinfo.tos = tc->t_cpath->cp_conn->c_tos;
 261
 262                 rds_info_copy(iter, &tsinfo, sizeof(tsinfo));
 263         }
 264
 265 out:
 266         lens->nr = rds_tcp_tc_count;
 267         lens->each = sizeof(tsinfo);
 268
 269         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
 270 }
 271
 272 #if IS_ENABLED(CONFIG_IPV6)
 273 /* Handle RDS6_INFO_TCP_SOCKETS socket option. It returns both IPv4 and
 274  * IPv6 connections. IPv4 connection address is returned in an IPv4 mapped
 275  * address.
 276  */
 277 static void rds6_tcp_tc_info(struct socket *sock, unsigned int len,
 278                              struct rds_info_iterator *iter,
 279                              struct rds_info_lengths *lens)
 280 {
 281         struct rds6_info_tcp_socket tsinfo6;
 282         struct rds_tcp_connection *tc;
 283         unsigned long flags;
 284
 285         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
 286
 287         if (len / sizeof(tsinfo6) < rds6_tcp_tc_count)
 288                 goto out;
 289
 290         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
 291                 struct sock *sk = tc->t_sock->sk;
 292                 struct inet_sock *inet = inet_sk(sk);
 293
 294                 tsinfo6.local_addr = sk->sk_v6_rcv_saddr;
 295                 tsinfo6.local_port = inet->inet_sport;
 296                 tsinfo6.peer_addr = sk->sk_v6_daddr;
 297                 tsinfo6.peer_port = inet->inet_dport;
 298
 299                 tsinfo6.hdr_rem = tc->t_tinc_hdr_rem;
 300                 tsinfo6.data_rem = tc->t_tinc_data_rem;
 301                 tsinfo6.last_sent_nxt = tc->t_last_sent_nxt;
 302                 tsinfo6.last_expected_una = tc->t_last_expected_una;
 303                 tsinfo6.last_seen_una = tc->t_last_seen_una;
 304
 305                 rds_info_copy(iter, &tsinfo6, sizeof(tsinfo6));
 306         }
 307
 308 out:
 309         lens->nr = rds6_tcp_tc_count;
 310         lens->each = sizeof(tsinfo6);
 311
 312         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
 313 }
 314 #endif
 315
 316 static int rds_tcp_laddr_check(struct net *net, const struct in6_addr *addr,
 317                                __u32 scope_id)
 318 {
 319         struct net_device *dev = NULL;
 320 #if IS_ENABLED(CONFIG_IPV6)
 321         int ret;
 322 #endif
 323
 324         if (ipv6_addr_v4mapped(addr)) {
 325                 if (inet_addr_type(net, addr->s6_addr32[3]) == RTN_LOCAL)
 326                         return 0;
 327                 return -EADDRNOTAVAIL;
 328         }
 329
 330         /* If the scope_id is specified, check only those addresses
 331          * hosted on the specified interface.
 332          */
 333         if (scope_id != 0) {
 334                 rcu_read_lock();
 335                 dev = dev_get_by_index_rcu(net, scope_id);
 336                 /* scope_id is not valid... */
 337                 if (!dev) {
 338                         rcu_read_unlock();
 339                         return -EADDRNOTAVAIL;
 340                 }
 341                 rcu_read_unlock();
 342         }
 343 #if IS_ENABLED(CONFIG_IPV6)
 344         ret = ipv6_chk_addr(net, addr, dev, 0);
 345         if (ret)
 346                 return 0;
 347 #endif
 348         return -EADDRNOTAVAIL;
 349 }
 350
 351 static void rds_tcp_conn_free(void *arg)
 352 {
 353         struct rds_tcp_connection *tc = arg;
 354         unsigned long flags;
 355
 356         rdsdebug("freeing tc %p\n", tc);
 357
 358         spin_lock_irqsave(&rds_tcp_conn_lock, flags);
 359         if (!tc->t_tcp_node_detached)
 360                 list_del(&tc->t_tcp_node);
 361         spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
 362
 363         kmem_cache_free(rds_tcp_conn_slab, tc);
 364 }
 365
 366 static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
 367 {
 368         struct rds_tcp_connection *tc;
 369         int i, j;
 370         int ret = 0;
 371
 372         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 373                 tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
 374                 if (!tc) {
 375                         ret = -ENOMEM;
 376                         goto fail;
 377                 }
 378                 mutex_init(&tc->t_conn_path_lock);
 379                 tc->t_sock = NULL;
 380                 tc->t_tinc = NULL;
 381                 tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 382                 tc->t_tinc_data_rem = 0;
 383
 384                 conn->c_path[i].cp_transport_data = tc;
 385                 tc->t_cpath = &conn->c_path[i];
 386                 tc->t_tcp_node_detached = true;
 387
 388                 rdsdebug("rds_conn_path [%d] tc %p\n", i,
 389                          conn->c_path[i].cp_transport_data);
 390         }
 391         spin_lock_irq(&rds_tcp_conn_lock);
 392         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 393                 tc = conn->c_path[i].cp_transport_data;
 394                 tc->t_tcp_node_detached = false;
 395                 list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
 396         }
 397         spin_unlock_irq(&rds_tcp_conn_lock);
 398 fail:
 399         if (ret) {
 400                 for (j = 0; j < i; j++)
 401                         rds_tcp_conn_free(conn->c_path[j].cp_transport_data);
 402         }
 403         return ret;
 404 }
 405
 406 static bool list_has_conn(struct list_head *list, struct rds_connection *conn)
 407 {
 408         struct rds_tcp_connection *tc, *_tc;
 409
 410         list_for_each_entry_safe(tc, _tc, list, t_tcp_node) {
 411                 if (tc->t_cpath->cp_conn == conn)
 412                         return true;
 413         }
 414         return false;
 415 }
 416
 417 static void rds_tcp_set_unloading(void)
 418 {
 419         atomic_set(&rds_tcp_unloading, 1);
 420 }
 421
 422 static bool rds_tcp_is_unloading(struct rds_connection *conn)
 423 {
 424         return atomic_read(&rds_tcp_unloading) != 0;
 425 }
 426
 427 static void rds_tcp_destroy_conns(void)
 428 {
 429         struct rds_tcp_connection *tc, *_tc;
 430         LIST_HEAD(tmp_list);
 431
 432         /* avoid calling conn_destroy with irqs off */
 433         spin_lock_irq(&rds_tcp_conn_lock);
 434         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 435                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
 436                         list_move_tail(&tc->t_tcp_node, &tmp_list);
 437         }
 438         spin_unlock_irq(&rds_tcp_conn_lock);
 439
 440         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
 441                 rds_conn_destroy(tc->t_cpath->cp_conn);
 442 }
 443
 444 static void rds_tcp_exit(void);
 445
 446 static u8 rds_tcp_get_tos_map(u8 tos)
 447 {
 448         /* all user tos mapped to default 0 for TCP transport */
 449         return 0;
 450 }
 451
 452 struct rds_transport rds_tcp_transport = {
 453         .laddr_check            = rds_tcp_laddr_check,
 454         .xmit_path_prepare      = rds_tcp_xmit_path_prepare,
 455         .xmit_path_complete     = rds_tcp_xmit_path_complete,
 456         .xmit                   = rds_tcp_xmit,
 457         .recv_path              = rds_tcp_recv_path,
 458         .conn_alloc             = rds_tcp_conn_alloc,
 459         .conn_free              = rds_tcp_conn_free,
 460         .conn_path_connect      = rds_tcp_conn_path_connect,
 461         .conn_path_shutdown     = rds_tcp_conn_path_shutdown,
 462         .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
 463         .inc_free               = rds_tcp_inc_free,
 464         .stats_info_copy        = rds_tcp_stats_info_copy,
 465         .exit                   = rds_tcp_exit,
 466         .get_tos_map            = rds_tcp_get_tos_map,
 467         .t_owner                = THIS_MODULE,
 468         .t_name                 = "tcp",
 469         .t_type                 = RDS_TRANS_TCP,
 470         .t_prefer_loopback      = 1,
 471         .t_mp_capable           = 1,
 472         .t_unloading            = rds_tcp_is_unloading,
 473 };
 474
 475 static unsigned int rds_tcp_netid;
 476
 477 /* per-network namespace private data for this module */
 478 struct rds_tcp_net {
 479         struct socket *rds_tcp_listen_sock;
 480         struct work_struct rds_tcp_accept_w;
 481         struct ctl_table_header *rds_tcp_sysctl;
 482         struct ctl_table *ctl_table;
 483         int sndbuf_size;
 484         int rcvbuf_size;
 485 };
 486
 487 /* All module specific customizations to the RDS-TCP socket should be done in
 488  * rds_tcp_tune() and applied after socket creation.
 489  */
 490 void rds_tcp_tune(struct socket *sock)
 491 {
 492         struct sock *sk = sock->sk;
 493         struct net *net = sock_net(sk);
 494         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 495
 496         tcp_sock_set_nodelay(sock->sk);
 497         lock_sock(sk);
 498         if (rtn->sndbuf_size > 0) {
 499                 sk->sk_sndbuf = rtn->sndbuf_size;
 500                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
 501         }
 502         if (rtn->rcvbuf_size > 0) {
 503                 sk->sk_sndbuf = rtn->rcvbuf_size;
 504                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
 505         }
 506         release_sock(sk);
 507 }
 508
 509 static void rds_tcp_accept_worker(struct work_struct *work)
 510 {
 511         struct rds_tcp_net *rtn = container_of(work,
 512                                                struct rds_tcp_net,
 513                                                rds_tcp_accept_w);
 514
 515         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
 516                 cond_resched();
 517 }
 518
 519 void rds_tcp_accept_work(struct sock *sk)
 520 {
 521         struct net *net = sock_net(sk);
 522         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 523
 524         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
 525 }
 526
 527 static __net_init int rds_tcp_init_net(struct net *net)
 528 {
 529         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 530         struct ctl_table *tbl;
 531         int err = 0;
 532
 533         memset(rtn, 0, sizeof(*rtn));
 534
 535         /* {snd, rcv}buf_size default to 0, which implies we let the
 536          * stack pick the value, and permit auto-tuning of buffer size.
 537          */
 538         if (net == &init_net) {
 539                 tbl = rds_tcp_sysctl_table;
 540         } else {
 541                 tbl = kmemdup(rds_tcp_sysctl_table,
 542                               sizeof(rds_tcp_sysctl_table), GFP_KERNEL);
 543                 if (!tbl) {
 544                         pr_warn("could not set allocate sysctl table\n");
 545                         return -ENOMEM;
 546                 }
 547                 rtn->ctl_table = tbl;
 548         }
 549         tbl[RDS_TCP_SNDBUF].data = &rtn->sndbuf_size;
 550         tbl[RDS_TCP_RCVBUF].data = &rtn->rcvbuf_size;
 551         rtn->rds_tcp_sysctl = register_net_sysctl(net, "net/rds/tcp", tbl);
 552         if (!rtn->rds_tcp_sysctl) {
 553                 pr_warn("could not register sysctl\n");
 554                 err = -ENOMEM;
 555                 goto fail;
 556         }
 557
 558 #if IS_ENABLED(CONFIG_IPV6)
 559         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, true);
 560 #else
 561         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
 562 #endif
 563         if (!rtn->rds_tcp_listen_sock) {
 564                 pr_warn("could not set up IPv6 listen sock\n");
 565
 566 #if IS_ENABLED(CONFIG_IPV6)
 567                 /* Try IPv4 as some systems disable IPv6 */
 568                 rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
 569                 if (!rtn->rds_tcp_listen_sock) {
 570 #endif
 571                         unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
 572                         rtn->rds_tcp_sysctl = NULL;
 573                         err = -EAFNOSUPPORT;
 574                         goto fail;
 575 #if IS_ENABLED(CONFIG_IPV6)
 576                 }
 577 #endif
 578         }
 579         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
 580         return 0;
 581
 582 fail:
 583         if (net != &init_net)
 584                 kfree(tbl);
 585         return err;
 586 }
 587
 588 static void rds_tcp_kill_sock(struct net *net)
 589 {
 590         struct rds_tcp_connection *tc, *_tc;
 591         LIST_HEAD(tmp_list);
 592         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 593         struct socket *lsock = rtn->rds_tcp_listen_sock;
 594
 595         rtn->rds_tcp_listen_sock = NULL;
 596         rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w);
 597         spin_lock_irq(&rds_tcp_conn_lock);
 598         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 599                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
 600
 601                 if (net != c_net)
 602                         continue;
 603                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
 604                         list_move_tail(&tc->t_tcp_node, &tmp_list);
 605                 } else {
 606                         list_del(&tc->t_tcp_node);
 607                         tc->t_tcp_node_detached = true;
 608                 }
 609         }
 610         spin_unlock_irq(&rds_tcp_conn_lock);
 611         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
 612                 rds_conn_destroy(tc->t_cpath->cp_conn);
 613 }
 614
 615 static void __net_exit rds_tcp_exit_net(struct net *net)
 616 {
 617         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 618
 619         rds_tcp_kill_sock(net);
 620
 621         if (rtn->rds_tcp_sysctl)
 622                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
 623
 624         if (net != &init_net)
 625                 kfree(rtn->ctl_table);
 626 }
 627
 628 static struct pernet_operations rds_tcp_net_ops = {
 629         .init = rds_tcp_init_net,
 630         .exit = rds_tcp_exit_net,
 631         .id = &rds_tcp_netid,
 632         .size = sizeof(struct rds_tcp_net),
 633 };
 634
 635 void *rds_tcp_listen_sock_def_readable(struct net *net)
 636 {
 637         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 638         struct socket *lsock = rtn->rds_tcp_listen_sock;
 639
 640         if (!lsock)
 641                 return NULL;
 642
 643         return lsock->sk->sk_user_data;
 644 }
 645
 646 /* when sysctl is used to modify some kernel socket parameters,this
 647  * function  resets the RDS connections in that netns  so that we can
 648  * restart with new parameters.  The assumption is that such reset
 649  * events are few and far-between.
 650  */
 651 static void rds_tcp_sysctl_reset(struct net *net)
 652 {
 653         struct rds_tcp_connection *tc, *_tc;
 654
 655         spin_lock_irq(&rds_tcp_conn_lock);
 656         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 657                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
 658
 659                 if (net != c_net || !tc->t_sock)
 660                         continue;
 661
 662                 /* reconnect with new parameters */
 663                 rds_conn_path_drop(tc->t_cpath, false);
 664         }
 665         spin_unlock_irq(&rds_tcp_conn_lock);
 666 }
 667
 668 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
 669                                  void *buffer, size_t *lenp, loff_t *fpos)
 670 {
 671         struct net *net = current->nsproxy->net_ns;
 672         int err;
 673
 674         err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
 675         if (err < 0) {
 676                 pr_warn("Invalid input. Must be >= %d\n",
 677                         *(int *)(ctl->extra1));
 678                 return err;
 679         }
 680         if (write)
 681                 rds_tcp_sysctl_reset(net);
 682         return 0;
 683 }
 684
 685 static void rds_tcp_exit(void)
 686 {
 687         rds_tcp_set_unloading();
 688         synchronize_rcu();
 689         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 690 #if IS_ENABLED(CONFIG_IPV6)
 691         rds_info_deregister_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
 692 #endif
 693         unregister_pernet_device(&rds_tcp_net_ops);
 694         rds_tcp_destroy_conns();
 695         rds_trans_unregister(&rds_tcp_transport);
 696         rds_tcp_recv_exit();
 697         kmem_cache_destroy(rds_tcp_conn_slab);
 698 }
 699 module_exit(rds_tcp_exit);
 700
 701 static int rds_tcp_init(void)
 702 {
 703         int ret;
 704
 705         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
 706                                               sizeof(struct rds_tcp_connection),
 707                                               0, 0, NULL);
 708         if (!rds_tcp_conn_slab) {
 709                 ret = -ENOMEM;
 710                 goto out;
 711         }
 712
 713         ret = rds_tcp_recv_init();
 714         if (ret)
 715                 goto out_slab;
 716
 717         ret = register_pernet_device(&rds_tcp_net_ops);
 718         if (ret)
 719                 goto out_recv;
 720
 721         rds_trans_register(&rds_tcp_transport);
 722
 723         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 724 #if IS_ENABLED(CONFIG_IPV6)
 725         rds_info_register_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
 726 #endif
 727
 728         goto out;
 729 out_recv:
 730         rds_tcp_recv_exit();
 731 out_slab:
 732         kmem_cache_destroy(rds_tcp_conn_slab);
 733 out:
 734         return ret;
 735 }
 736 module_init(rds_tcp_init);
 737
 738 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
 739 MODULE_DESCRIPTION("RDS: TCP transport");
 740 MODULE_LICENSE("Dual BSD/GPL");