GNU Linux-libre 6.6.31-gnu
[releases.git] / 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         /* reset receive side state for rds_tcp_data_recv() for osock  */
170         cancel_delayed_work_sync(&cp->cp_send_w);
171         cancel_delayed_work_sync(&cp->cp_recv_w);
172         lock_sock(osock->sk);
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 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 bool 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;
495
496         tcp_sock_set_nodelay(sock->sk);
497         lock_sock(sk);
498         /* TCP timer functions might access net namespace even after
499          * a process which created this net namespace terminated.
500          */
501         if (!sk->sk_net_refcnt) {
502                 if (!maybe_get_net(net)) {
503                         release_sock(sk);
504                         return false;
505                 }
506                 /* Update ns_tracker to current stack trace and refcounted tracker */
507                 __netns_tracker_free(net, &sk->ns_tracker, false);
508
509                 sk->sk_net_refcnt = 1;
510                 netns_tracker_alloc(net, &sk->ns_tracker, GFP_KERNEL);
511                 sock_inuse_add(net, 1);
512         }
513         rtn = net_generic(net, rds_tcp_netid);
514         if (rtn->sndbuf_size > 0) {
515                 sk->sk_sndbuf = rtn->sndbuf_size;
516                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
517         }
518         if (rtn->rcvbuf_size > 0) {
519                 sk->sk_rcvbuf = rtn->rcvbuf_size;
520                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
521         }
522         release_sock(sk);
523         return true;
524 }
525
526 static void rds_tcp_accept_worker(struct work_struct *work)
527 {
528         struct rds_tcp_net *rtn = container_of(work,
529                                                struct rds_tcp_net,
530                                                rds_tcp_accept_w);
531
532         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
533                 cond_resched();
534 }
535
536 void rds_tcp_accept_work(struct sock *sk)
537 {
538         struct net *net = sock_net(sk);
539         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
540
541         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
542 }
543
544 static __net_init int rds_tcp_init_net(struct net *net)
545 {
546         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
547         struct ctl_table *tbl;
548         int err = 0;
549
550         memset(rtn, 0, sizeof(*rtn));
551
552         /* {snd, rcv}buf_size default to 0, which implies we let the
553          * stack pick the value, and permit auto-tuning of buffer size.
554          */
555         if (net == &init_net) {
556                 tbl = rds_tcp_sysctl_table;
557         } else {
558                 tbl = kmemdup(rds_tcp_sysctl_table,
559                               sizeof(rds_tcp_sysctl_table), GFP_KERNEL);
560                 if (!tbl) {
561                         pr_warn("could not set allocate sysctl table\n");
562                         return -ENOMEM;
563                 }
564                 rtn->ctl_table = tbl;
565         }
566         tbl[RDS_TCP_SNDBUF].data = &rtn->sndbuf_size;
567         tbl[RDS_TCP_RCVBUF].data = &rtn->rcvbuf_size;
568         rtn->rds_tcp_sysctl = register_net_sysctl_sz(net, "net/rds/tcp", tbl,
569                                                      ARRAY_SIZE(rds_tcp_sysctl_table));
570         if (!rtn->rds_tcp_sysctl) {
571                 pr_warn("could not register sysctl\n");
572                 err = -ENOMEM;
573                 goto fail;
574         }
575
576 #if IS_ENABLED(CONFIG_IPV6)
577         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, true);
578 #else
579         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
580 #endif
581         if (!rtn->rds_tcp_listen_sock) {
582                 pr_warn("could not set up IPv6 listen sock\n");
583
584 #if IS_ENABLED(CONFIG_IPV6)
585                 /* Try IPv4 as some systems disable IPv6 */
586                 rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
587                 if (!rtn->rds_tcp_listen_sock) {
588 #endif
589                         unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
590                         rtn->rds_tcp_sysctl = NULL;
591                         err = -EAFNOSUPPORT;
592                         goto fail;
593 #if IS_ENABLED(CONFIG_IPV6)
594                 }
595 #endif
596         }
597         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
598         return 0;
599
600 fail:
601         if (net != &init_net)
602                 kfree(tbl);
603         return err;
604 }
605
606 static void rds_tcp_kill_sock(struct net *net)
607 {
608         struct rds_tcp_connection *tc, *_tc;
609         LIST_HEAD(tmp_list);
610         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
611         struct socket *lsock = rtn->rds_tcp_listen_sock;
612
613         rtn->rds_tcp_listen_sock = NULL;
614         rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w);
615         spin_lock_irq(&rds_tcp_conn_lock);
616         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
617                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
618
619                 if (net != c_net)
620                         continue;
621                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
622                         list_move_tail(&tc->t_tcp_node, &tmp_list);
623                 } else {
624                         list_del(&tc->t_tcp_node);
625                         tc->t_tcp_node_detached = true;
626                 }
627         }
628         spin_unlock_irq(&rds_tcp_conn_lock);
629         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
630                 rds_conn_destroy(tc->t_cpath->cp_conn);
631 }
632
633 static void __net_exit rds_tcp_exit_net(struct net *net)
634 {
635         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
636
637         rds_tcp_kill_sock(net);
638
639         if (rtn->rds_tcp_sysctl)
640                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
641
642         if (net != &init_net)
643                 kfree(rtn->ctl_table);
644 }
645
646 static struct pernet_operations rds_tcp_net_ops = {
647         .init = rds_tcp_init_net,
648         .exit = rds_tcp_exit_net,
649         .id = &rds_tcp_netid,
650         .size = sizeof(struct rds_tcp_net),
651 };
652
653 void *rds_tcp_listen_sock_def_readable(struct net *net)
654 {
655         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
656         struct socket *lsock = rtn->rds_tcp_listen_sock;
657
658         if (!lsock)
659                 return NULL;
660
661         return lsock->sk->sk_user_data;
662 }
663
664 /* when sysctl is used to modify some kernel socket parameters,this
665  * function  resets the RDS connections in that netns  so that we can
666  * restart with new parameters.  The assumption is that such reset
667  * events are few and far-between.
668  */
669 static void rds_tcp_sysctl_reset(struct net *net)
670 {
671         struct rds_tcp_connection *tc, *_tc;
672
673         spin_lock_irq(&rds_tcp_conn_lock);
674         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
675                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
676
677                 if (net != c_net || !tc->t_sock)
678                         continue;
679
680                 /* reconnect with new parameters */
681                 rds_conn_path_drop(tc->t_cpath, false);
682         }
683         spin_unlock_irq(&rds_tcp_conn_lock);
684 }
685
686 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
687                                  void *buffer, size_t *lenp, loff_t *fpos)
688 {
689         struct net *net = current->nsproxy->net_ns;
690         int err;
691
692         err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
693         if (err < 0) {
694                 pr_warn("Invalid input. Must be >= %d\n",
695                         *(int *)(ctl->extra1));
696                 return err;
697         }
698         if (write)
699                 rds_tcp_sysctl_reset(net);
700         return 0;
701 }
702
703 static void rds_tcp_exit(void)
704 {
705         rds_tcp_set_unloading();
706         synchronize_rcu();
707         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
708 #if IS_ENABLED(CONFIG_IPV6)
709         rds_info_deregister_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
710 #endif
711         unregister_pernet_device(&rds_tcp_net_ops);
712         rds_tcp_destroy_conns();
713         rds_trans_unregister(&rds_tcp_transport);
714         rds_tcp_recv_exit();
715         kmem_cache_destroy(rds_tcp_conn_slab);
716 }
717 module_exit(rds_tcp_exit);
718
719 static int __init rds_tcp_init(void)
720 {
721         int ret;
722
723         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
724                                               sizeof(struct rds_tcp_connection),
725                                               0, 0, NULL);
726         if (!rds_tcp_conn_slab) {
727                 ret = -ENOMEM;
728                 goto out;
729         }
730
731         ret = rds_tcp_recv_init();
732         if (ret)
733                 goto out_slab;
734
735         ret = register_pernet_device(&rds_tcp_net_ops);
736         if (ret)
737                 goto out_recv;
738
739         rds_trans_register(&rds_tcp_transport);
740
741         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
742 #if IS_ENABLED(CONFIG_IPV6)
743         rds_info_register_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
744 #endif
745
746         goto out;
747 out_recv:
748         rds_tcp_recv_exit();
749 out_slab:
750         kmem_cache_destroy(rds_tcp_conn_slab);
751 out:
752         return ret;
753 }
754 module_init(rds_tcp_init);
755
756 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
757 MODULE_DESCRIPTION("RDS: TCP transport");
758 MODULE_LICENSE("Dual BSD/GPL");