net/rds/tcp.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  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
  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 static unsigned int rds_tcp_tc_count;
  49
  50 /* Track rds_tcp_connection structs so they can be cleaned up */
  51 static DEFINE_SPINLOCK(rds_tcp_conn_lock);
  52 static LIST_HEAD(rds_tcp_conn_list);
  53
  54 static struct kmem_cache *rds_tcp_conn_slab;
  55
  56 #define RDS_TCP_DEFAULT_BUFSIZE (128 * 1024)
  57
  58 /* doing it this way avoids calling tcp_sk() */
  59 void rds_tcp_nonagle(struct socket *sock)
  60 {
  61         mm_segment_t oldfs = get_fs();
  62         int val = 1;
  63
  64         set_fs(KERNEL_DS);
  65         sock->ops->setsockopt(sock, SOL_TCP, TCP_NODELAY, (char __user *)&val,
  66                               sizeof(val));
  67         set_fs(oldfs);
  68 }
  69
  70 void rds_tcp_tune(struct socket *sock)
  71 {
  72         struct sock *sk = sock->sk;
  73
  74         rds_tcp_nonagle(sock);
  75
  76         /*
  77          * We're trying to saturate gigabit with the default,
  78          * see svc_sock_setbufsize().
  79          */
  80         lock_sock(sk);
  81         sk->sk_sndbuf = RDS_TCP_DEFAULT_BUFSIZE;
  82         sk->sk_rcvbuf = RDS_TCP_DEFAULT_BUFSIZE;
  83         sk->sk_userlocks |= SOCK_SNDBUF_LOCK|SOCK_RCVBUF_LOCK;
  84         release_sock(sk);
  85 }
  86
  87 u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc)
  88 {
  89         return tcp_sk(tc->t_sock->sk)->snd_nxt;
  90 }
  91
  92 u32 rds_tcp_snd_una(struct rds_tcp_connection *tc)
  93 {
  94         return tcp_sk(tc->t_sock->sk)->snd_una;
  95 }
  96
  97 void rds_tcp_restore_callbacks(struct socket *sock,
  98                                struct rds_tcp_connection *tc)
  99 {
 100         rdsdebug("restoring sock %p callbacks from tc %p\n", sock, tc);
 101         write_lock_bh(&sock->sk->sk_callback_lock);
 102
 103         /* done under the callback_lock to serialize with write_space */
 104         spin_lock(&rds_tcp_tc_list_lock);
 105         list_del_init(&tc->t_list_item);
 106         rds_tcp_tc_count--;
 107         spin_unlock(&rds_tcp_tc_list_lock);
 108
 109         tc->t_sock = NULL;
 110
 111         sock->sk->sk_write_space = tc->t_orig_write_space;
 112         sock->sk->sk_data_ready = tc->t_orig_data_ready;
 113         sock->sk->sk_state_change = tc->t_orig_state_change;
 114         sock->sk->sk_user_data = NULL;
 115
 116         write_unlock_bh(&sock->sk->sk_callback_lock);
 117 }
 118
 119 /*
 120  * This is the only path that sets tc->t_sock.  Send and receive trust that
 121  * it is set.  The RDS_CONN_CONNECTED bit protects those paths from being
 122  * called while it isn't set.
 123  */
 124 void rds_tcp_set_callbacks(struct socket *sock, struct rds_connection *conn)
 125 {
 126         struct rds_tcp_connection *tc = conn->c_transport_data;
 127
 128         rdsdebug("setting sock %p callbacks to tc %p\n", sock, tc);
 129         write_lock_bh(&sock->sk->sk_callback_lock);
 130
 131         /* done under the callback_lock to serialize with write_space */
 132         spin_lock(&rds_tcp_tc_list_lock);
 133         list_add_tail(&tc->t_list_item, &rds_tcp_tc_list);
 134         rds_tcp_tc_count++;
 135         spin_unlock(&rds_tcp_tc_list_lock);
 136
 137         /* accepted sockets need our listen data ready undone */
 138         if (sock->sk->sk_data_ready == rds_tcp_listen_data_ready)
 139                 sock->sk->sk_data_ready = sock->sk->sk_user_data;
 140
 141         tc->t_sock = sock;
 142         tc->conn = conn;
 143         tc->t_orig_data_ready = sock->sk->sk_data_ready;
 144         tc->t_orig_write_space = sock->sk->sk_write_space;
 145         tc->t_orig_state_change = sock->sk->sk_state_change;
 146
 147         sock->sk->sk_user_data = conn;
 148         sock->sk->sk_data_ready = rds_tcp_data_ready;
 149         sock->sk->sk_write_space = rds_tcp_write_space;
 150         sock->sk->sk_state_change = rds_tcp_state_change;
 151
 152         write_unlock_bh(&sock->sk->sk_callback_lock);
 153 }
 154
 155 static void rds_tcp_tc_info(struct socket *sock, unsigned int len,
 156                             struct rds_info_iterator *iter,
 157                             struct rds_info_lengths *lens)
 158 {
 159         struct rds_info_tcp_socket tsinfo;
 160         struct rds_tcp_connection *tc;
 161         unsigned long flags;
 162         struct sockaddr_in sin;
 163         int sinlen;
 164
 165         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
 166
 167         if (len / sizeof(tsinfo) < rds_tcp_tc_count)
 168                 goto out;
 169
 170         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
 171
 172                 sock->ops->getname(sock, (struct sockaddr *)&sin, &sinlen, 0);
 173                 tsinfo.local_addr = sin.sin_addr.s_addr;
 174                 tsinfo.local_port = sin.sin_port;
 175                 sock->ops->getname(sock, (struct sockaddr *)&sin, &sinlen, 1);
 176                 tsinfo.peer_addr = sin.sin_addr.s_addr;
 177                 tsinfo.peer_port = sin.sin_port;
 178
 179                 tsinfo.hdr_rem = tc->t_tinc_hdr_rem;
 180                 tsinfo.data_rem = tc->t_tinc_data_rem;
 181                 tsinfo.last_sent_nxt = tc->t_last_sent_nxt;
 182                 tsinfo.last_expected_una = tc->t_last_expected_una;
 183                 tsinfo.last_seen_una = tc->t_last_seen_una;
 184
 185                 rds_info_copy(iter, &tsinfo, sizeof(tsinfo));
 186         }
 187
 188 out:
 189         lens->nr = rds_tcp_tc_count;
 190         lens->each = sizeof(tsinfo);
 191
 192         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
 193 }
 194
 195 static int rds_tcp_laddr_check(struct net *net, __be32 addr)
 196 {
 197         if (inet_addr_type(net, addr) == RTN_LOCAL)
 198                 return 0;
 199         return -EADDRNOTAVAIL;
 200 }
 201
 202 static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
 203 {
 204         struct rds_tcp_connection *tc;
 205
 206         tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
 207         if (!tc)
 208                 return -ENOMEM;
 209
 210         tc->t_sock = NULL;
 211         tc->t_tinc = NULL;
 212         tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 213         tc->t_tinc_data_rem = 0;
 214
 215         conn->c_transport_data = tc;
 216
 217         spin_lock_irq(&rds_tcp_conn_lock);
 218         list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
 219         spin_unlock_irq(&rds_tcp_conn_lock);
 220
 221         rdsdebug("alloced tc %p\n", conn->c_transport_data);
 222         return 0;
 223 }
 224
 225 static void rds_tcp_conn_free(void *arg)
 226 {
 227         struct rds_tcp_connection *tc = arg;
 228         unsigned long flags;
 229         rdsdebug("freeing tc %p\n", tc);
 230
 231         spin_lock_irqsave(&rds_tcp_conn_lock, flags);
 232         list_del(&tc->t_tcp_node);
 233         spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
 234
 235         kmem_cache_free(rds_tcp_conn_slab, tc);
 236 }
 237
 238 static void rds_tcp_destroy_conns(void)
 239 {
 240         struct rds_tcp_connection *tc, *_tc;
 241         LIST_HEAD(tmp_list);
 242
 243         /* avoid calling conn_destroy with irqs off */
 244         spin_lock_irq(&rds_tcp_conn_lock);
 245         list_splice(&rds_tcp_conn_list, &tmp_list);
 246         INIT_LIST_HEAD(&rds_tcp_conn_list);
 247         spin_unlock_irq(&rds_tcp_conn_lock);
 248
 249         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
 250                 if (tc->conn->c_passive)
 251                         rds_conn_destroy(tc->conn->c_passive);
 252                 rds_conn_destroy(tc->conn);
 253         }
 254 }
 255
 256 static void rds_tcp_exit(void);
 257
 258 struct rds_transport rds_tcp_transport = {
 259         .laddr_check            = rds_tcp_laddr_check,
 260         .xmit_prepare           = rds_tcp_xmit_prepare,
 261         .xmit_complete          = rds_tcp_xmit_complete,
 262         .xmit                   = rds_tcp_xmit,
 263         .recv                   = rds_tcp_recv,
 264         .conn_alloc             = rds_tcp_conn_alloc,
 265         .conn_free              = rds_tcp_conn_free,
 266         .conn_connect           = rds_tcp_conn_connect,
 267         .conn_shutdown          = rds_tcp_conn_shutdown,
 268         .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
 269         .inc_free               = rds_tcp_inc_free,
 270         .stats_info_copy        = rds_tcp_stats_info_copy,
 271         .exit                   = rds_tcp_exit,
 272         .t_owner                = THIS_MODULE,
 273         .t_name                 = "tcp",
 274         .t_type                 = RDS_TRANS_TCP,
 275         .t_prefer_loopback      = 1,
 276 };
 277
 278 static int rds_tcp_netid;
 279
 280 /* per-network namespace private data for this module */
 281 struct rds_tcp_net {
 282         struct socket *rds_tcp_listen_sock;
 283         struct work_struct rds_tcp_accept_w;
 284 };
 285
 286 static void rds_tcp_accept_worker(struct work_struct *work)
 287 {
 288         struct rds_tcp_net *rtn = container_of(work,
 289                                                struct rds_tcp_net,
 290                                                rds_tcp_accept_w);
 291
 292         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
 293                 cond_resched();
 294 }
 295
 296 void rds_tcp_accept_work(struct sock *sk)
 297 {
 298         struct net *net = sock_net(sk);
 299         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 300
 301         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
 302 }
 303
 304 static __net_init int rds_tcp_init_net(struct net *net)
 305 {
 306         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 307
 308         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net);
 309         if (!rtn->rds_tcp_listen_sock) {
 310                 pr_warn("could not set up listen sock\n");
 311                 return -EAFNOSUPPORT;
 312         }
 313         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
 314         return 0;
 315 }
 316
 317 static void __net_exit rds_tcp_exit_net(struct net *net)
 318 {
 319         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 320
 321         /* If rds_tcp_exit_net() is called as a result of netns deletion,
 322          * the rds_tcp_kill_sock() device notifier would already have cleaned
 323          * up the listen socket, thus there is no work to do in this function.
 324          *
 325          * If rds_tcp_exit_net() is called as a result of module unload,
 326          * i.e., due to rds_tcp_exit() -> unregister_pernet_subsys(), then
 327          * we do need to clean up the listen socket here.
 328          */
 329         if (rtn->rds_tcp_listen_sock) {
 330                 rds_tcp_listen_stop(rtn->rds_tcp_listen_sock);
 331                 rtn->rds_tcp_listen_sock = NULL;
 332                 flush_work(&rtn->rds_tcp_accept_w);
 333         }
 334 }
 335
 336 static struct pernet_operations rds_tcp_net_ops = {
 337         .init = rds_tcp_init_net,
 338         .exit = rds_tcp_exit_net,
 339         .id = &rds_tcp_netid,
 340         .size = sizeof(struct rds_tcp_net),
 341 };
 342
 343 static void rds_tcp_kill_sock(struct net *net)
 344 {
 345         struct rds_tcp_connection *tc, *_tc;
 346         struct sock *sk;
 347         LIST_HEAD(tmp_list);
 348         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 349
 350         rds_tcp_listen_stop(rtn->rds_tcp_listen_sock);
 351         rtn->rds_tcp_listen_sock = NULL;
 352         flush_work(&rtn->rds_tcp_accept_w);
 353         spin_lock_irq(&rds_tcp_conn_lock);
 354         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 355                 struct net *c_net = read_pnet(&tc->conn->c_net);
 356
 357                 if (net != c_net || !tc->t_sock)
 358                         continue;
 359                 list_move_tail(&tc->t_tcp_node, &tmp_list);
 360         }
 361         spin_unlock_irq(&rds_tcp_conn_lock);
 362         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
 363                 sk = tc->t_sock->sk;
 364                 sk->sk_prot->disconnect(sk, 0);
 365                 tcp_done(sk);
 366                 if (tc->conn->c_passive)
 367                         rds_conn_destroy(tc->conn->c_passive);
 368                 rds_conn_destroy(tc->conn);
 369         }
 370 }
 371
 372 static int rds_tcp_dev_event(struct notifier_block *this,
 373                              unsigned long event, void *ptr)
 374 {
 375         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 376
 377         /* rds-tcp registers as a pernet subys, so the ->exit will only
 378          * get invoked after network acitivity has quiesced. We need to
 379          * clean up all sockets  to quiesce network activity, and use
 380          * the unregistration of the per-net loopback device as a trigger
 381          * to start that cleanup.
 382          */
 383         if (event == NETDEV_UNREGISTER_FINAL &&
 384             dev->ifindex == LOOPBACK_IFINDEX)
 385                 rds_tcp_kill_sock(dev_net(dev));
 386
 387         return NOTIFY_DONE;
 388 }
 389
 390 static struct notifier_block rds_tcp_dev_notifier = {
 391         .notifier_call        = rds_tcp_dev_event,
 392         .priority = -10, /* must be called after other network notifiers */
 393 };
 394
 395 static void rds_tcp_exit(void)
 396 {
 397         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 398         unregister_pernet_subsys(&rds_tcp_net_ops);
 399         if (unregister_netdevice_notifier(&rds_tcp_dev_notifier))
 400                 pr_warn("could not unregister rds_tcp_dev_notifier\n");
 401         rds_tcp_destroy_conns();
 402         rds_trans_unregister(&rds_tcp_transport);
 403         rds_tcp_recv_exit();
 404         kmem_cache_destroy(rds_tcp_conn_slab);
 405 }
 406 module_exit(rds_tcp_exit);
 407
 408 static int rds_tcp_init(void)
 409 {
 410         int ret;
 411
 412         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
 413                                               sizeof(struct rds_tcp_connection),
 414                                               0, 0, NULL);
 415         if (!rds_tcp_conn_slab) {
 416                 ret = -ENOMEM;
 417                 goto out;
 418         }
 419
 420         ret = register_netdevice_notifier(&rds_tcp_dev_notifier);
 421         if (ret) {
 422                 pr_warn("could not register rds_tcp_dev_notifier\n");
 423                 goto out;
 424         }
 425
 426         ret = register_pernet_subsys(&rds_tcp_net_ops);
 427         if (ret)
 428                 goto out_slab;
 429
 430         ret = rds_tcp_recv_init();
 431         if (ret)
 432                 goto out_slab;
 433
 434         ret = rds_trans_register(&rds_tcp_transport);
 435         if (ret)
 436                 goto out_recv;
 437
 438         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 439
 440         goto out;
 441
 442 out_recv:
 443         rds_tcp_recv_exit();
 444 out_slab:
 445         unregister_pernet_subsys(&rds_tcp_net_ops);
 446         kmem_cache_destroy(rds_tcp_conn_slab);
 447 out:
 448         return ret;
 449 }
 450 module_init(rds_tcp_init);
 451
 452 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
 453 MODULE_DESCRIPTION("RDS: TCP transport");
 454 MODULE_LICENSE("Dual BSD/GPL");
 455