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/tcp.h>
  41 #include <net/addrconf.h>
  42
  43 #include "rds.h"
  44 #include "tcp.h"
  45
  46 /* only for info exporting */
  47 static DEFINE_SPINLOCK(rds_tcp_tc_list_lock);
  48 static LIST_HEAD(rds_tcp_tc_list);
  49
  50 /* rds_tcp_tc_count counts only IPv4 connections.
  51  * rds6_tcp_tc_count counts both IPv4 and IPv6 connections.
  52  */
  53 static unsigned int rds_tcp_tc_count;
  54 #if IS_ENABLED(CONFIG_IPV6)
  55 static unsigned int rds6_tcp_tc_count;
  56 #endif
  57
  58 /* Track rds_tcp_connection structs so they can be cleaned up */
  59 static DEFINE_SPINLOCK(rds_tcp_conn_lock);
  60 static LIST_HEAD(rds_tcp_conn_list);
  61 static atomic_t rds_tcp_unloading = ATOMIC_INIT(0);
  62
  63 static struct kmem_cache *rds_tcp_conn_slab;
  64
  65 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
  66                                  void __user *buffer, size_t *lenp,
  67                                  loff_t *fpos);
  68
  69 static int rds_tcp_min_sndbuf = SOCK_MIN_SNDBUF;
  70 static int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;
  71
  72 static struct ctl_table rds_tcp_sysctl_table[] = {
  73 #define RDS_TCP_SNDBUF  0
  74         {
  75                 .procname       = "rds_tcp_sndbuf",
  76                 /* data is per-net pointer */
  77                 .maxlen         = sizeof(int),
  78                 .mode           = 0644,
  79                 .proc_handler   = rds_tcp_skbuf_handler,
  80                 .extra1         = &rds_tcp_min_sndbuf,
  81         },
  82 #define RDS_TCP_RCVBUF  1
  83         {
  84                 .procname       = "rds_tcp_rcvbuf",
  85                 /* data is per-net pointer */
  86                 .maxlen         = sizeof(int),
  87                 .mode           = 0644,
  88                 .proc_handler   = rds_tcp_skbuf_handler,
  89                 .extra1         = &rds_tcp_min_rcvbuf,
  90         },
  91         { }
  92 };
  93
  94 /* doing it this way avoids calling tcp_sk() */
  95 void rds_tcp_nonagle(struct socket *sock)
  96 {
  97         int val = 1;
  98
  99         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (void *)&val,
 100                               sizeof(val));
 101 }
 102
 103 u32 rds_tcp_write_seq(struct rds_tcp_connection *tc)
 104 {
 105         /* seq# of the last byte of data in tcp send buffer */
 106         return tcp_sk(tc->t_sock->sk)->write_seq;
 107 }
 108
 109 u32 rds_tcp_snd_una(struct rds_tcp_connection *tc)
 110 {
 111         return tcp_sk(tc->t_sock->sk)->snd_una;
 112 }
 113
 114 void rds_tcp_restore_callbacks(struct socket *sock,
 115                                struct rds_tcp_connection *tc)
 116 {
 117         rdsdebug("restoring sock %p callbacks from tc %p\n", sock, tc);
 118         write_lock_bh(&sock->sk->sk_callback_lock);
 119
 120         /* done under the callback_lock to serialize with write_space */
 121         spin_lock(&rds_tcp_tc_list_lock);
 122         list_del_init(&tc->t_list_item);
 123 #if IS_ENABLED(CONFIG_IPV6)
 124         rds6_tcp_tc_count--;
 125 #endif
 126         if (!tc->t_cpath->cp_conn->c_isv6)
 127                 rds_tcp_tc_count--;
 128         spin_unlock(&rds_tcp_tc_list_lock);
 129
 130         tc->t_sock = NULL;
 131
 132         sock->sk->sk_write_space = tc->t_orig_write_space;
 133         sock->sk->sk_data_ready = tc->t_orig_data_ready;
 134         sock->sk->sk_state_change = tc->t_orig_state_change;
 135         sock->sk->sk_user_data = NULL;
 136
 137         write_unlock_bh(&sock->sk->sk_callback_lock);
 138 }
 139
 140 /*
 141  * rds_tcp_reset_callbacks() switches the to the new sock and
 142  * returns the existing tc->t_sock.
 143  *
 144  * The only functions that set tc->t_sock are rds_tcp_set_callbacks
 145  * and rds_tcp_reset_callbacks.  Send and receive trust that
 146  * it is set.  The absence of RDS_CONN_UP bit protects those paths
 147  * from being called while it isn't set.
 148  */
 149 void rds_tcp_reset_callbacks(struct socket *sock,
 150                              struct rds_conn_path *cp)
 151 {
 152         struct rds_tcp_connection *tc = cp->cp_transport_data;
 153         struct socket *osock = tc->t_sock;
 154
 155         if (!osock)
 156                 goto newsock;
 157
 158         /* Need to resolve a duelling SYN between peers.
 159          * We have an outstanding SYN to this peer, which may
 160          * potentially have transitioned to the RDS_CONN_UP state,
 161          * so we must quiesce any send threads before resetting
 162          * cp_transport_data. We quiesce these threads by setting
 163          * cp_state to something other than RDS_CONN_UP, and then
 164          * waiting for any existing threads in rds_send_xmit to
 165          * complete release_in_xmit(). (Subsequent threads entering
 166          * rds_send_xmit() will bail on !rds_conn_up().
 167          *
 168          * However an incoming syn-ack at this point would end up
 169          * marking the conn as RDS_CONN_UP, and would again permit
 170          * rds_send_xmi() threads through, so ideally we would
 171          * synchronize on RDS_CONN_UP after lock_sock(), but cannot
 172          * do that: waiting on !RDS_IN_XMIT after lock_sock() may
 173          * end up deadlocking with tcp_sendmsg(), and the RDS_IN_XMIT
 174          * would not get set. As a result, we set c_state to
 175          * RDS_CONN_RESETTTING, to ensure that rds_tcp_state_change
 176          * cannot mark rds_conn_path_up() in the window before lock_sock()
 177          */
 178         atomic_set(&cp->cp_state, RDS_CONN_RESETTING);
 179         wait_event(cp->cp_waitq, !test_bit(RDS_IN_XMIT, &cp->cp_flags));
 180         lock_sock(osock->sk);
 181         /* reset receive side state for rds_tcp_data_recv() for osock  */
 182         cancel_delayed_work_sync(&cp->cp_send_w);
 183         cancel_delayed_work_sync(&cp->cp_recv_w);
 184         if (tc->t_tinc) {
 185                 rds_inc_put(&tc->t_tinc->ti_inc);
 186                 tc->t_tinc = NULL;
 187         }
 188         tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 189         tc->t_tinc_data_rem = 0;
 190         rds_tcp_restore_callbacks(osock, tc);
 191         release_sock(osock->sk);
 192         sock_release(osock);
 193 newsock:
 194         rds_send_path_reset(cp);
 195         lock_sock(sock->sk);
 196         rds_tcp_set_callbacks(sock, cp);
 197         release_sock(sock->sk);
 198 }
 199
 200 /* Add tc to rds_tcp_tc_list and set tc->t_sock. See comments
 201  * above rds_tcp_reset_callbacks for notes about synchronization
 202  * with data path
 203  */
 204 void rds_tcp_set_callbacks(struct socket *sock, struct rds_conn_path *cp)
 205 {
 206         struct rds_tcp_connection *tc = cp->cp_transport_data;
 207
 208         rdsdebug("setting sock %p callbacks to tc %p\n", sock, tc);
 209         write_lock_bh(&sock->sk->sk_callback_lock);
 210
 211         /* done under the callback_lock to serialize with write_space */
 212         spin_lock(&rds_tcp_tc_list_lock);
 213         list_add_tail(&tc->t_list_item, &rds_tcp_tc_list);
 214 #if IS_ENABLED(CONFIG_IPV6)
 215         rds6_tcp_tc_count++;
 216 #endif
 217         if (!tc->t_cpath->cp_conn->c_isv6)
 218                 rds_tcp_tc_count++;
 219         spin_unlock(&rds_tcp_tc_list_lock);
 220
 221         /* accepted sockets need our listen data ready undone */
 222         if (sock->sk->sk_data_ready == rds_tcp_listen_data_ready)
 223                 sock->sk->sk_data_ready = sock->sk->sk_user_data;
 224
 225         tc->t_sock = sock;
 226         tc->t_cpath = cp;
 227         tc->t_orig_data_ready = sock->sk->sk_data_ready;
 228         tc->t_orig_write_space = sock->sk->sk_write_space;
 229         tc->t_orig_state_change = sock->sk->sk_state_change;
 230
 231         sock->sk->sk_user_data = cp;
 232         sock->sk->sk_data_ready = rds_tcp_data_ready;
 233         sock->sk->sk_write_space = rds_tcp_write_space;
 234         sock->sk->sk_state_change = rds_tcp_state_change;
 235
 236         write_unlock_bh(&sock->sk->sk_callback_lock);
 237 }
 238
 239 /* Handle RDS_INFO_TCP_SOCKETS socket option.  It only returns IPv4
 240  * connections for backward compatibility.
 241  */
 242 static void rds_tcp_tc_info(struct socket *rds_sock, unsigned int len,
 243                             struct rds_info_iterator *iter,
 244                             struct rds_info_lengths *lens)
 245 {
 246         struct rds_info_tcp_socket tsinfo;
 247         struct rds_tcp_connection *tc;
 248         unsigned long flags;
 249
 250         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
 251
 252         if (len / sizeof(tsinfo) < rds_tcp_tc_count)
 253                 goto out;
 254
 255         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
 256                 struct inet_sock *inet = inet_sk(tc->t_sock->sk);
 257
 258                 if (tc->t_cpath->cp_conn->c_isv6)
 259                         continue;
 260
 261                 tsinfo.local_addr = inet->inet_saddr;
 262                 tsinfo.local_port = inet->inet_sport;
 263                 tsinfo.peer_addr = inet->inet_daddr;
 264                 tsinfo.peer_port = inet->inet_dport;
 265
 266                 tsinfo.hdr_rem = tc->t_tinc_hdr_rem;
 267                 tsinfo.data_rem = tc->t_tinc_data_rem;
 268                 tsinfo.last_sent_nxt = tc->t_last_sent_nxt;
 269                 tsinfo.last_expected_una = tc->t_last_expected_una;
 270                 tsinfo.last_seen_una = tc->t_last_seen_una;
 271
 272                 rds_info_copy(iter, &tsinfo, sizeof(tsinfo));
 273         }
 274
 275 out:
 276         lens->nr = rds_tcp_tc_count;
 277         lens->each = sizeof(tsinfo);
 278
 279         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
 280 }
 281
 282 #if IS_ENABLED(CONFIG_IPV6)
 283 /* Handle RDS6_INFO_TCP_SOCKETS socket option. It returns both IPv4 and
 284  * IPv6 connections. IPv4 connection address is returned in an IPv4 mapped
 285  * address.
 286  */
 287 static void rds6_tcp_tc_info(struct socket *sock, unsigned int len,
 288                              struct rds_info_iterator *iter,
 289                              struct rds_info_lengths *lens)
 290 {
 291         struct rds6_info_tcp_socket tsinfo6;
 292         struct rds_tcp_connection *tc;
 293         unsigned long flags;
 294
 295         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
 296
 297         if (len / sizeof(tsinfo6) < rds6_tcp_tc_count)
 298                 goto out;
 299
 300         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
 301                 struct sock *sk = tc->t_sock->sk;
 302                 struct inet_sock *inet = inet_sk(sk);
 303
 304                 tsinfo6.local_addr = sk->sk_v6_rcv_saddr;
 305                 tsinfo6.local_port = inet->inet_sport;
 306                 tsinfo6.peer_addr = sk->sk_v6_daddr;
 307                 tsinfo6.peer_port = inet->inet_dport;
 308
 309                 tsinfo6.hdr_rem = tc->t_tinc_hdr_rem;
 310                 tsinfo6.data_rem = tc->t_tinc_data_rem;
 311                 tsinfo6.last_sent_nxt = tc->t_last_sent_nxt;
 312                 tsinfo6.last_expected_una = tc->t_last_expected_una;
 313                 tsinfo6.last_seen_una = tc->t_last_seen_una;
 314
 315                 rds_info_copy(iter, &tsinfo6, sizeof(tsinfo6));
 316         }
 317
 318 out:
 319         lens->nr = rds6_tcp_tc_count;
 320         lens->each = sizeof(tsinfo6);
 321
 322         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
 323 }
 324 #endif
 325
 326 static int rds_tcp_laddr_check(struct net *net, const struct in6_addr *addr,
 327                                __u32 scope_id)
 328 {
 329         struct net_device *dev = NULL;
 330 #if IS_ENABLED(CONFIG_IPV6)
 331         int ret;
 332 #endif
 333
 334         if (ipv6_addr_v4mapped(addr)) {
 335                 if (inet_addr_type(net, addr->s6_addr32[3]) == RTN_LOCAL)
 336                         return 0;
 337                 return -EADDRNOTAVAIL;
 338         }
 339
 340         /* If the scope_id is specified, check only those addresses
 341          * hosted on the specified interface.
 342          */
 343         if (scope_id != 0) {
 344                 rcu_read_lock();
 345                 dev = dev_get_by_index_rcu(net, scope_id);
 346                 /* scope_id is not valid... */
 347                 if (!dev) {
 348                         rcu_read_unlock();
 349                         return -EADDRNOTAVAIL;
 350                 }
 351                 rcu_read_unlock();
 352         }
 353 #if IS_ENABLED(CONFIG_IPV6)
 354         ret = ipv6_chk_addr(net, addr, dev, 0);
 355         if (ret)
 356                 return 0;
 357 #endif
 358         return -EADDRNOTAVAIL;
 359 }
 360
 361 static void rds_tcp_conn_free(void *arg)
 362 {
 363         struct rds_tcp_connection *tc = arg;
 364         unsigned long flags;
 365
 366         rdsdebug("freeing tc %p\n", tc);
 367
 368         spin_lock_irqsave(&rds_tcp_conn_lock, flags);
 369         if (!tc->t_tcp_node_detached)
 370                 list_del(&tc->t_tcp_node);
 371         spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
 372
 373         kmem_cache_free(rds_tcp_conn_slab, tc);
 374 }
 375
 376 static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
 377 {
 378         struct rds_tcp_connection *tc;
 379         int i, j;
 380         int ret = 0;
 381
 382         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 383                 tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
 384                 if (!tc) {
 385                         ret = -ENOMEM;
 386                         goto fail;
 387                 }
 388                 mutex_init(&tc->t_conn_path_lock);
 389                 tc->t_sock = NULL;
 390                 tc->t_tinc = NULL;
 391                 tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 392                 tc->t_tinc_data_rem = 0;
 393
 394                 conn->c_path[i].cp_transport_data = tc;
 395                 tc->t_cpath = &conn->c_path[i];
 396                 tc->t_tcp_node_detached = true;
 397
 398                 rdsdebug("rds_conn_path [%d] tc %p\n", i,
 399                          conn->c_path[i].cp_transport_data);
 400         }
 401         spin_lock_irq(&rds_tcp_conn_lock);
 402         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 403                 tc = conn->c_path[i].cp_transport_data;
 404                 tc->t_tcp_node_detached = false;
 405                 list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
 406         }
 407         spin_unlock_irq(&rds_tcp_conn_lock);
 408 fail:
 409         if (ret) {
 410                 for (j = 0; j < i; j++)
 411                         rds_tcp_conn_free(conn->c_path[j].cp_transport_data);
 412         }
 413         return ret;
 414 }
 415
 416 static bool list_has_conn(struct list_head *list, struct rds_connection *conn)
 417 {
 418         struct rds_tcp_connection *tc, *_tc;
 419
 420         list_for_each_entry_safe(tc, _tc, list, t_tcp_node) {
 421                 if (tc->t_cpath->cp_conn == conn)
 422                         return true;
 423         }
 424         return false;
 425 }
 426
 427 static void rds_tcp_set_unloading(void)
 428 {
 429         atomic_set(&rds_tcp_unloading, 1);
 430 }
 431
 432 static bool rds_tcp_is_unloading(struct rds_connection *conn)
 433 {
 434         return atomic_read(&rds_tcp_unloading) != 0;
 435 }
 436
 437 static void rds_tcp_destroy_conns(void)
 438 {
 439         struct rds_tcp_connection *tc, *_tc;
 440         LIST_HEAD(tmp_list);
 441
 442         /* avoid calling conn_destroy with irqs off */
 443         spin_lock_irq(&rds_tcp_conn_lock);
 444         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 445                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
 446                         list_move_tail(&tc->t_tcp_node, &tmp_list);
 447         }
 448         spin_unlock_irq(&rds_tcp_conn_lock);
 449
 450         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
 451                 rds_conn_destroy(tc->t_cpath->cp_conn);
 452 }
 453
 454 static void rds_tcp_exit(void);
 455
 456 struct rds_transport rds_tcp_transport = {
 457         .laddr_check            = rds_tcp_laddr_check,
 458         .xmit_path_prepare      = rds_tcp_xmit_path_prepare,
 459         .xmit_path_complete     = rds_tcp_xmit_path_complete,
 460         .xmit                   = rds_tcp_xmit,
 461         .recv_path              = rds_tcp_recv_path,
 462         .conn_alloc             = rds_tcp_conn_alloc,
 463         .conn_free              = rds_tcp_conn_free,
 464         .conn_path_connect      = rds_tcp_conn_path_connect,
 465         .conn_path_shutdown     = rds_tcp_conn_path_shutdown,
 466         .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
 467         .inc_free               = rds_tcp_inc_free,
 468         .stats_info_copy        = rds_tcp_stats_info_copy,
 469         .exit                   = rds_tcp_exit,
 470         .t_owner                = THIS_MODULE,
 471         .t_name                 = "tcp",
 472         .t_type                 = RDS_TRANS_TCP,
 473         .t_prefer_loopback      = 1,
 474         .t_mp_capable           = 1,
 475         .t_unloading            = rds_tcp_is_unloading,
 476 };
 477
 478 static unsigned int rds_tcp_netid;
 479
 480 /* per-network namespace private data for this module */
 481 struct rds_tcp_net {
 482         struct socket *rds_tcp_listen_sock;
 483         struct work_struct rds_tcp_accept_w;
 484         struct ctl_table_header *rds_tcp_sysctl;
 485         struct ctl_table *ctl_table;
 486         int sndbuf_size;
 487         int rcvbuf_size;
 488 };
 489
 490 /* All module specific customizations to the RDS-TCP socket should be done in
 491  * rds_tcp_tune() and applied after socket creation.
 492  */
 493 void rds_tcp_tune(struct socket *sock)
 494 {
 495         struct sock *sk = sock->sk;
 496         struct net *net = sock_net(sk);
 497         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 498
 499         rds_tcp_nonagle(sock);
 500         lock_sock(sk);
 501         if (rtn->sndbuf_size > 0) {
 502                 sk->sk_sndbuf = rtn->sndbuf_size;
 503                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
 504         }
 505         if (rtn->rcvbuf_size > 0) {
 506                 sk->sk_sndbuf = rtn->rcvbuf_size;
 507                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
 508         }
 509         release_sock(sk);
 510 }
 511
 512 static void rds_tcp_accept_worker(struct work_struct *work)
 513 {
 514         struct rds_tcp_net *rtn = container_of(work,
 515                                                struct rds_tcp_net,
 516                                                rds_tcp_accept_w);
 517
 518         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
 519                 cond_resched();
 520 }
 521
 522 void rds_tcp_accept_work(struct sock *sk)
 523 {
 524         struct net *net = sock_net(sk);
 525         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 526
 527         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
 528 }
 529
 530 static __net_init int rds_tcp_init_net(struct net *net)
 531 {
 532         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 533         struct ctl_table *tbl;
 534         int err = 0;
 535
 536         memset(rtn, 0, sizeof(*rtn));
 537
 538         /* {snd, rcv}buf_size default to 0, which implies we let the
 539          * stack pick the value, and permit auto-tuning of buffer size.
 540          */
 541         if (net == &init_net) {
 542                 tbl = rds_tcp_sysctl_table;
 543         } else {
 544                 tbl = kmemdup(rds_tcp_sysctl_table,
 545                               sizeof(rds_tcp_sysctl_table), GFP_KERNEL);
 546                 if (!tbl) {
 547                         pr_warn("could not set allocate syctl table\n");
 548                         return -ENOMEM;
 549                 }
 550                 rtn->ctl_table = tbl;
 551         }
 552         tbl[RDS_TCP_SNDBUF].data = &rtn->sndbuf_size;
 553         tbl[RDS_TCP_RCVBUF].data = &rtn->rcvbuf_size;
 554         rtn->rds_tcp_sysctl = register_net_sysctl(net, "net/rds/tcp", tbl);
 555         if (!rtn->rds_tcp_sysctl) {
 556                 pr_warn("could not register sysctl\n");
 557                 err = -ENOMEM;
 558                 goto fail;
 559         }
 560
 561 #if IS_ENABLED(CONFIG_IPV6)
 562         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, true);
 563 #else
 564         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
 565 #endif
 566         if (!rtn->rds_tcp_listen_sock) {
 567                 pr_warn("could not set up IPv6 listen sock\n");
 568
 569 #if IS_ENABLED(CONFIG_IPV6)
 570                 /* Try IPv4 as some systems disable IPv6 */
 571                 rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
 572                 if (!rtn->rds_tcp_listen_sock) {
 573 #endif
 574                         unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
 575                         rtn->rds_tcp_sysctl = NULL;
 576                         err = -EAFNOSUPPORT;
 577                         goto fail;
 578 #if IS_ENABLED(CONFIG_IPV6)
 579                 }
 580 #endif
 581         }
 582         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
 583         return 0;
 584
 585 fail:
 586         if (net != &init_net)
 587                 kfree(tbl);
 588         return err;
 589 }
 590
 591 static void rds_tcp_kill_sock(struct net *net)
 592 {
 593         struct rds_tcp_connection *tc, *_tc;
 594         LIST_HEAD(tmp_list);
 595         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 596         struct socket *lsock = rtn->rds_tcp_listen_sock;
 597
 598         rtn->rds_tcp_listen_sock = NULL;
 599         rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w);
 600         spin_lock_irq(&rds_tcp_conn_lock);
 601         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 602                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
 603
 604                 if (net != c_net || !tc->t_sock)
 605                         continue;
 606                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
 607                         list_move_tail(&tc->t_tcp_node, &tmp_list);
 608                 } else {
 609                         list_del(&tc->t_tcp_node);
 610                         tc->t_tcp_node_detached = true;
 611                 }
 612         }
 613         spin_unlock_irq(&rds_tcp_conn_lock);
 614         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
 615                 rds_conn_destroy(tc->t_cpath->cp_conn);
 616 }
 617
 618 static void __net_exit rds_tcp_exit_net(struct net *net)
 619 {
 620         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 621
 622         rds_tcp_kill_sock(net);
 623
 624         if (rtn->rds_tcp_sysctl)
 625                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
 626
 627         if (net != &init_net && rtn->ctl_table)
 628                 kfree(rtn->ctl_table);
 629 }
 630
 631 static struct pernet_operations rds_tcp_net_ops = {
 632         .init = rds_tcp_init_net,
 633         .exit = rds_tcp_exit_net,
 634         .id = &rds_tcp_netid,
 635         .size = sizeof(struct rds_tcp_net),
 636 };
 637
 638 void *rds_tcp_listen_sock_def_readable(struct net *net)
 639 {
 640         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 641         struct socket *lsock = rtn->rds_tcp_listen_sock;
 642
 643         if (!lsock)
 644                 return NULL;
 645
 646         return lsock->sk->sk_user_data;
 647 }
 648
 649 /* when sysctl is used to modify some kernel socket parameters,this
 650  * function  resets the RDS connections in that netns  so that we can
 651  * restart with new parameters.  The assumption is that such reset
 652  * events are few and far-between.
 653  */
 654 static void rds_tcp_sysctl_reset(struct net *net)
 655 {
 656         struct rds_tcp_connection *tc, *_tc;
 657
 658         spin_lock_irq(&rds_tcp_conn_lock);
 659         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 660                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
 661
 662                 if (net != c_net || !tc->t_sock)
 663                         continue;
 664
 665                 /* reconnect with new parameters */
 666                 rds_conn_path_drop(tc->t_cpath, false);
 667         }
 668         spin_unlock_irq(&rds_tcp_conn_lock);
 669 }
 670
 671 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
 672                                  void __user *buffer, size_t *lenp,
 673                                  loff_t *fpos)
 674 {
 675         struct net *net = current->nsproxy->net_ns;
 676         int err;
 677
 678         err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
 679         if (err < 0) {
 680                 pr_warn("Invalid input. Must be >= %d\n",
 681                         *(int *)(ctl->extra1));
 682                 return err;
 683         }
 684         if (write)
 685                 rds_tcp_sysctl_reset(net);
 686         return 0;
 687 }
 688
 689 static void rds_tcp_exit(void)
 690 {
 691         rds_tcp_set_unloading();
 692         synchronize_rcu();
 693         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 694 #if IS_ENABLED(CONFIG_IPV6)
 695         rds_info_deregister_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
 696 #endif
 697         unregister_pernet_device(&rds_tcp_net_ops);
 698         rds_tcp_destroy_conns();
 699         rds_trans_unregister(&rds_tcp_transport);
 700         rds_tcp_recv_exit();
 701         kmem_cache_destroy(rds_tcp_conn_slab);
 702 }
 703 module_exit(rds_tcp_exit);
 704
 705 static int rds_tcp_init(void)
 706 {
 707         int ret;
 708
 709         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
 710                                               sizeof(struct rds_tcp_connection),
 711                                               0, 0, NULL);
 712         if (!rds_tcp_conn_slab) {
 713                 ret = -ENOMEM;
 714                 goto out;
 715         }
 716
 717         ret = rds_tcp_recv_init();
 718         if (ret)
 719                 goto out_slab;
 720
 721         ret = register_pernet_device(&rds_tcp_net_ops);
 722         if (ret)
 723                 goto out_recv;
 724
 725         rds_trans_register(&rds_tcp_transport);
 726
 727         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 728 #if IS_ENABLED(CONFIG_IPV6)
 729         rds_info_register_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
 730 #endif
 731
 732         goto out;
 733 out_recv:
 734         rds_tcp_recv_exit();
 735 out_slab:
 736         kmem_cache_destroy(rds_tcp_conn_slab);
 737 out:
 738         return ret;
 739 }
 740 module_init(rds_tcp_init);
 741
 742 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
 743 MODULE_DESCRIPTION("RDS: TCP transport");
 744 MODULE_LICENSE("Dual BSD/GPL");