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TOMOYO Linux Cross Reference
Linux/net/rds/tcp.c

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  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         lock_sock(osock->sk);
180         /* reset receive side state for rds_tcp_data_recv() for osock  */
181         cancel_delayed_work_sync(&cp->cp_send_w);
182         cancel_delayed_work_sync(&cp->cp_recv_w);
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                 tsinfo.tos = tc->t_cpath->cp_conn->c_tos;
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 static u8 rds_tcp_get_tos_map(u8 tos)
457 {
458         /* all user tos mapped to default 0 for TCP transport */
459         return 0;
460 }
461 
462 struct rds_transport rds_tcp_transport = {
463         .laddr_check            = rds_tcp_laddr_check,
464         .xmit_path_prepare      = rds_tcp_xmit_path_prepare,
465         .xmit_path_complete     = rds_tcp_xmit_path_complete,
466         .xmit                   = rds_tcp_xmit,
467         .recv_path              = rds_tcp_recv_path,
468         .conn_alloc             = rds_tcp_conn_alloc,
469         .conn_free              = rds_tcp_conn_free,
470         .conn_path_connect      = rds_tcp_conn_path_connect,
471         .conn_path_shutdown     = rds_tcp_conn_path_shutdown,
472         .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
473         .inc_free               = rds_tcp_inc_free,
474         .stats_info_copy        = rds_tcp_stats_info_copy,
475         .exit                   = rds_tcp_exit,
476         .get_tos_map            = rds_tcp_get_tos_map,
477         .t_owner                = THIS_MODULE,
478         .t_name                 = "tcp",
479         .t_type                 = RDS_TRANS_TCP,
480         .t_prefer_loopback      = 1,
481         .t_mp_capable           = 1,
482         .t_unloading            = rds_tcp_is_unloading,
483 };
484 
485 static unsigned int rds_tcp_netid;
486 
487 /* per-network namespace private data for this module */
488 struct rds_tcp_net {
489         struct socket *rds_tcp_listen_sock;
490         struct work_struct rds_tcp_accept_w;
491         struct ctl_table_header *rds_tcp_sysctl;
492         struct ctl_table *ctl_table;
493         int sndbuf_size;
494         int rcvbuf_size;
495 };
496 
497 /* All module specific customizations to the RDS-TCP socket should be done in
498  * rds_tcp_tune() and applied after socket creation.
499  */
500 void rds_tcp_tune(struct socket *sock)
501 {
502         struct sock *sk = sock->sk;
503         struct net *net = sock_net(sk);
504         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
505 
506         rds_tcp_nonagle(sock);
507         lock_sock(sk);
508         if (rtn->sndbuf_size > 0) {
509                 sk->sk_sndbuf = rtn->sndbuf_size;
510                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
511         }
512         if (rtn->rcvbuf_size > 0) {
513                 sk->sk_sndbuf = rtn->rcvbuf_size;
514                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
515         }
516         release_sock(sk);
517 }
518 
519 static void rds_tcp_accept_worker(struct work_struct *work)
520 {
521         struct rds_tcp_net *rtn = container_of(work,
522                                                struct rds_tcp_net,
523                                                rds_tcp_accept_w);
524 
525         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
526                 cond_resched();
527 }
528 
529 void rds_tcp_accept_work(struct sock *sk)
530 {
531         struct net *net = sock_net(sk);
532         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
533 
534         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
535 }
536 
537 static __net_init int rds_tcp_init_net(struct net *net)
538 {
539         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
540         struct ctl_table *tbl;
541         int err = 0;
542 
543         memset(rtn, 0, sizeof(*rtn));
544 
545         /* {snd, rcv}buf_size default to 0, which implies we let the
546          * stack pick the value, and permit auto-tuning of buffer size.
547          */
548         if (net == &init_net) {
549                 tbl = rds_tcp_sysctl_table;
550         } else {
551                 tbl = kmemdup(rds_tcp_sysctl_table,
552                               sizeof(rds_tcp_sysctl_table), GFP_KERNEL);
553                 if (!tbl) {
554                         pr_warn("could not set allocate sysctl table\n");
555                         return -ENOMEM;
556                 }
557                 rtn->ctl_table = tbl;
558         }
559         tbl[RDS_TCP_SNDBUF].data = &rtn->sndbuf_size;
560         tbl[RDS_TCP_RCVBUF].data = &rtn->rcvbuf_size;
561         rtn->rds_tcp_sysctl = register_net_sysctl(net, "net/rds/tcp", tbl);
562         if (!rtn->rds_tcp_sysctl) {
563                 pr_warn("could not register sysctl\n");
564                 err = -ENOMEM;
565                 goto fail;
566         }
567 
568 #if IS_ENABLED(CONFIG_IPV6)
569         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, true);
570 #else
571         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
572 #endif
573         if (!rtn->rds_tcp_listen_sock) {
574                 pr_warn("could not set up IPv6 listen sock\n");
575 
576 #if IS_ENABLED(CONFIG_IPV6)
577                 /* Try IPv4 as some systems disable IPv6 */
578                 rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net, false);
579                 if (!rtn->rds_tcp_listen_sock) {
580 #endif
581                         unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
582                         rtn->rds_tcp_sysctl = NULL;
583                         err = -EAFNOSUPPORT;
584                         goto fail;
585 #if IS_ENABLED(CONFIG_IPV6)
586                 }
587 #endif
588         }
589         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
590         return 0;
591 
592 fail:
593         if (net != &init_net)
594                 kfree(tbl);
595         return err;
596 }
597 
598 static void rds_tcp_kill_sock(struct net *net)
599 {
600         struct rds_tcp_connection *tc, *_tc;
601         LIST_HEAD(tmp_list);
602         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
603         struct socket *lsock = rtn->rds_tcp_listen_sock;
604 
605         rtn->rds_tcp_listen_sock = NULL;
606         rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w);
607         spin_lock_irq(&rds_tcp_conn_lock);
608         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
609                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
610 
611                 if (net != c_net)
612                         continue;
613                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
614                         list_move_tail(&tc->t_tcp_node, &tmp_list);
615                 } else {
616                         list_del(&tc->t_tcp_node);
617                         tc->t_tcp_node_detached = true;
618                 }
619         }
620         spin_unlock_irq(&rds_tcp_conn_lock);
621         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
622                 rds_conn_destroy(tc->t_cpath->cp_conn);
623 }
624 
625 static void __net_exit rds_tcp_exit_net(struct net *net)
626 {
627         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
628 
629         rds_tcp_kill_sock(net);
630 
631         if (rtn->rds_tcp_sysctl)
632                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
633 
634         if (net != &init_net)
635                 kfree(rtn->ctl_table);
636 }
637 
638 static struct pernet_operations rds_tcp_net_ops = {
639         .init = rds_tcp_init_net,
640         .exit = rds_tcp_exit_net,
641         .id = &rds_tcp_netid,
642         .size = sizeof(struct rds_tcp_net),
643 };
644 
645 void *rds_tcp_listen_sock_def_readable(struct net *net)
646 {
647         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
648         struct socket *lsock = rtn->rds_tcp_listen_sock;
649 
650         if (!lsock)
651                 return NULL;
652 
653         return lsock->sk->sk_user_data;
654 }
655 
656 /* when sysctl is used to modify some kernel socket parameters,this
657  * function  resets the RDS connections in that netns  so that we can
658  * restart with new parameters.  The assumption is that such reset
659  * events are few and far-between.
660  */
661 static void rds_tcp_sysctl_reset(struct net *net)
662 {
663         struct rds_tcp_connection *tc, *_tc;
664 
665         spin_lock_irq(&rds_tcp_conn_lock);
666         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
667                 struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
668 
669                 if (net != c_net || !tc->t_sock)
670                         continue;
671 
672                 /* reconnect with new parameters */
673                 rds_conn_path_drop(tc->t_cpath, false);
674         }
675         spin_unlock_irq(&rds_tcp_conn_lock);
676 }
677 
678 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
679                                  void __user *buffer, size_t *lenp,
680                                  loff_t *fpos)
681 {
682         struct net *net = current->nsproxy->net_ns;
683         int err;
684 
685         err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
686         if (err < 0) {
687                 pr_warn("Invalid input. Must be >= %d\n",
688                         *(int *)(ctl->extra1));
689                 return err;
690         }
691         if (write)
692                 rds_tcp_sysctl_reset(net);
693         return 0;
694 }
695 
696 static void rds_tcp_exit(void)
697 {
698         rds_tcp_set_unloading();
699         synchronize_rcu();
700         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
701 #if IS_ENABLED(CONFIG_IPV6)
702         rds_info_deregister_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
703 #endif
704         unregister_pernet_device(&rds_tcp_net_ops);
705         rds_tcp_destroy_conns();
706         rds_trans_unregister(&rds_tcp_transport);
707         rds_tcp_recv_exit();
708         kmem_cache_destroy(rds_tcp_conn_slab);
709 }
710 module_exit(rds_tcp_exit);
711 
712 static int rds_tcp_init(void)
713 {
714         int ret;
715 
716         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
717                                               sizeof(struct rds_tcp_connection),
718                                               0, 0, NULL);
719         if (!rds_tcp_conn_slab) {
720                 ret = -ENOMEM;
721                 goto out;
722         }
723 
724         ret = rds_tcp_recv_init();
725         if (ret)
726                 goto out_slab;
727 
728         ret = register_pernet_device(&rds_tcp_net_ops);
729         if (ret)
730                 goto out_recv;
731 
732         rds_trans_register(&rds_tcp_transport);
733 
734         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
735 #if IS_ENABLED(CONFIG_IPV6)
736         rds_info_register_func(RDS6_INFO_TCP_SOCKETS, rds6_tcp_tc_info);
737 #endif
738 
739         goto out;
740 out_recv:
741         rds_tcp_recv_exit();
742 out_slab:
743         kmem_cache_destroy(rds_tcp_conn_slab);
744 out:
745         return ret;
746 }
747 module_init(rds_tcp_init);
748 
749 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
750 MODULE_DESCRIPTION("RDS: TCP transport");
751 MODULE_LICENSE("Dual BSD/GPL");
752 

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