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