1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Local endpoint object management
3 *
4 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/module.h>
11#include <linux/net.h>
12#include <linux/skbuff.h>
13#include <linux/slab.h>
14#include <linux/udp.h>
15#include <linux/ip.h>
16#include <linux/hashtable.h>
17#include <net/sock.h>
18#include <net/udp.h>
19#include <net/udp_tunnel.h>
20#include <net/af_rxrpc.h>
21#include "ar-internal.h"
22
23static void rxrpc_local_rcu(struct rcu_head *);
24
25/*
26 * Handle an ICMP/ICMP6 error turning up at the tunnel.  Push it through the
27 * usual mechanism so that it gets parsed and presented through the UDP
28 * socket's error_report().
29 */
30static void rxrpc_encap_err_rcv(struct sock *sk, struct sk_buff *skb, int err,
31				__be16 port, u32 info, u8 *payload)
32{
33	if (ip_hdr(skb)->version == IPVERSION)
34		return ip_icmp_error(sk, skb, err, port, info, payload);
35	if (IS_ENABLED(CONFIG_AF_RXRPC_IPV6))
36		return ipv6_icmp_error(sk, skb, err, port, info, payload);
37}
38
39/*
40 * Set or clear the Don't Fragment flag on a socket.
41 */
42void rxrpc_local_dont_fragment(const struct rxrpc_local *local, bool set)
43{
44	if (set)
45		ip_sock_set_mtu_discover(local->socket->sk, IP_PMTUDISC_DO);
46	else
47		ip_sock_set_mtu_discover(local->socket->sk, IP_PMTUDISC_DONT);
48}
49
50/*
51 * Compare a local to an address.  Return -ve, 0 or +ve to indicate less than,
52 * same or greater than.
53 *
54 * We explicitly don't compare the RxRPC service ID as we want to reject
55 * conflicting uses by differing services.  Further, we don't want to share
56 * addresses with different options (IPv6), so we don't compare those bits
57 * either.
58 */
59static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
60				const struct sockaddr_rxrpc *srx)
61{
62	long diff;
63
64	diff = ((local->srx.transport_type - srx->transport_type) ?:
65		(local->srx.transport_len - srx->transport_len) ?:
66		(local->srx.transport.family - srx->transport.family));
67	if (diff != 0)
68		return diff;
69
70	switch (srx->transport.family) {
71	case AF_INET:
72		/* If the choice of UDP port is left up to the transport, then
73		 * the endpoint record doesn't match.
74		 */
75		return ((u16 __force)local->srx.transport.sin.sin_port -
76			(u16 __force)srx->transport.sin.sin_port) ?:
77			memcmp(&local->srx.transport.sin.sin_addr,
78			       &srx->transport.sin.sin_addr,
79			       sizeof(struct in_addr));
80#ifdef CONFIG_AF_RXRPC_IPV6
81	case AF_INET6:
82		/* If the choice of UDP6 port is left up to the transport, then
83		 * the endpoint record doesn't match.
84		 */
85		return ((u16 __force)local->srx.transport.sin6.sin6_port -
86			(u16 __force)srx->transport.sin6.sin6_port) ?:
87			memcmp(&local->srx.transport.sin6.sin6_addr,
88			       &srx->transport.sin6.sin6_addr,
89			       sizeof(struct in6_addr));
90#endif
91	default:
92		BUG();
93	}
94}
95
96static void rxrpc_client_conn_reap_timeout(struct timer_list *timer)
97{
98	struct rxrpc_local *local =
99		container_of(timer, struct rxrpc_local, client_conn_reap_timer);
100
101	if (!local->kill_all_client_conns &&
102	    test_and_set_bit(RXRPC_CLIENT_CONN_REAP_TIMER, &local->client_conn_flags))
103		rxrpc_wake_up_io_thread(local);
104}
105
106/*
107 * Allocate a new local endpoint.
108 */
109static struct rxrpc_local *rxrpc_alloc_local(struct net *net,
110					     const struct sockaddr_rxrpc *srx)
111{
112	struct rxrpc_local *local;
113	u32 tmp;
114
115	local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
116	if (local) {
117		refcount_set(&local->ref, 1);
118		atomic_set(&local->active_users, 1);
119		local->net = net;
120		local->rxnet = rxrpc_net(net);
121		INIT_HLIST_NODE(&local->link);
122		init_completion(&local->io_thread_ready);
123#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
124		skb_queue_head_init(&local->rx_delay_queue);
125#endif
126		skb_queue_head_init(&local->rx_queue);
127		INIT_LIST_HEAD(&local->conn_attend_q);
128		INIT_LIST_HEAD(&local->call_attend_q);
129
130		local->client_bundles = RB_ROOT;
131		spin_lock_init(&local->client_bundles_lock);
132		local->kill_all_client_conns = false;
133		INIT_LIST_HEAD(&local->idle_client_conns);
134		timer_setup(&local->client_conn_reap_timer,
135			    rxrpc_client_conn_reap_timeout, 0);
136
137		spin_lock_init(&local->lock);
138		rwlock_init(&local->services_lock);
139		local->debug_id = atomic_inc_return(&rxrpc_debug_id);
140		memcpy(&local->srx, srx, sizeof(*srx));
141		local->srx.srx_service = 0;
142		idr_init(&local->conn_ids);
143		get_random_bytes(&tmp, sizeof(tmp));
144		tmp &= 0x3fffffff;
145		if (tmp == 0)
146			tmp = 1;
147		idr_set_cursor(&local->conn_ids, tmp);
148		INIT_LIST_HEAD(&local->new_client_calls);
149		spin_lock_init(&local->client_call_lock);
150
151		trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, 1);
152	}
153
154	_leave(" = %p", local);
155	return local;
156}
157
158/*
159 * create the local socket
160 * - must be called with rxrpc_local_mutex locked
161 */
162static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
163{
164	struct udp_tunnel_sock_cfg tuncfg = {NULL};
165	struct sockaddr_rxrpc *srx = &local->srx;
166	struct udp_port_cfg udp_conf = {0};
167	struct task_struct *io_thread;
168	struct sock *usk;
169	int ret;
170
171	_enter("%p{%d,%d}",
172	       local, srx->transport_type, srx->transport.family);
173
174	udp_conf.family = srx->transport.family;
175	udp_conf.use_udp_checksums = true;
176	if (udp_conf.family == AF_INET) {
177		udp_conf.local_ip = srx->transport.sin.sin_addr;
178		udp_conf.local_udp_port = srx->transport.sin.sin_port;
179#if IS_ENABLED(CONFIG_AF_RXRPC_IPV6)
180	} else {
181		udp_conf.local_ip6 = srx->transport.sin6.sin6_addr;
182		udp_conf.local_udp_port = srx->transport.sin6.sin6_port;
183		udp_conf.use_udp6_tx_checksums = true;
184		udp_conf.use_udp6_rx_checksums = true;
185#endif
186	}
187	ret = udp_sock_create(net, &udp_conf, &local->socket);
188	if (ret < 0) {
189		_leave(" = %d [socket]", ret);
190		return ret;
191	}
192
193	tuncfg.encap_type = UDP_ENCAP_RXRPC;
194	tuncfg.encap_rcv = rxrpc_encap_rcv;
195	tuncfg.encap_err_rcv = rxrpc_encap_err_rcv;
196	tuncfg.sk_user_data = local;
197	setup_udp_tunnel_sock(net, local->socket, &tuncfg);
198
199	/* set the socket up */
200	usk = local->socket->sk;
201	usk->sk_error_report = rxrpc_error_report;
202
203	switch (srx->transport.family) {
204	case AF_INET6:
205		/* we want to receive ICMPv6 errors */
206		ip6_sock_set_recverr(usk);
207
208		/* Fall through and set IPv4 options too otherwise we don't get
209		 * errors from IPv4 packets sent through the IPv6 socket.
210		 */
211		fallthrough;
212	case AF_INET:
213		/* we want to receive ICMP errors */
214		ip_sock_set_recverr(usk);
215
216		/* we want to set the don't fragment bit */
217		rxrpc_local_dont_fragment(local, true);
218
219		/* We want receive timestamps. */
220		sock_enable_timestamps(usk);
221		break;
222
223	default:
224		BUG();
225	}
226
227	io_thread = kthread_run(rxrpc_io_thread, local,
228				"krxrpcio/%u", ntohs(udp_conf.local_udp_port));
229	if (IS_ERR(io_thread)) {
230		ret = PTR_ERR(io_thread);
231		goto error_sock;
232	}
233
234	wait_for_completion(&local->io_thread_ready);
235	local->io_thread = io_thread;
236	_leave(" = 0");
237	return 0;
238
239error_sock:
240	kernel_sock_shutdown(local->socket, SHUT_RDWR);
241	local->socket->sk->sk_user_data = NULL;
242	sock_release(local->socket);
243	local->socket = NULL;
244	return ret;
245}
246
247/*
248 * Look up or create a new local endpoint using the specified local address.
249 */
250struct rxrpc_local *rxrpc_lookup_local(struct net *net,
251				       const struct sockaddr_rxrpc *srx)
252{
253	struct rxrpc_local *local;
254	struct rxrpc_net *rxnet = rxrpc_net(net);
255	struct hlist_node *cursor;
256	long diff;
257	int ret;
258
259	_enter("{%d,%d,%pISp}",
260	       srx->transport_type, srx->transport.family, &srx->transport);
261
262	mutex_lock(&rxnet->local_mutex);
263
264	hlist_for_each(cursor, &rxnet->local_endpoints) {
265		local = hlist_entry(cursor, struct rxrpc_local, link);
266
267		diff = rxrpc_local_cmp_key(local, srx);
268		if (diff != 0)
269			continue;
270
271		/* Services aren't allowed to share transport sockets, so
272		 * reject that here.  It is possible that the object is dying -
273		 * but it may also still have the local transport address that
274		 * we want bound.
275		 */
276		if (srx->srx_service) {
277			local = NULL;
278			goto addr_in_use;
279		}
280
281		/* Found a match.  We want to replace a dying object.
282		 * Attempting to bind the transport socket may still fail if
283		 * we're attempting to use a local address that the dying
284		 * object is still using.
285		 */
286		if (!rxrpc_use_local(local, rxrpc_local_use_lookup))
287			break;
288
289		goto found;
290	}
291
292	local = rxrpc_alloc_local(net, srx);
293	if (!local)
294		goto nomem;
295
296	ret = rxrpc_open_socket(local, net);
297	if (ret < 0)
298		goto sock_error;
299
300	if (cursor) {
301		hlist_replace_rcu(cursor, &local->link);
302		cursor->pprev = NULL;
303	} else {
304		hlist_add_head_rcu(&local->link, &rxnet->local_endpoints);
305	}
306
307found:
308	mutex_unlock(&rxnet->local_mutex);
309	_leave(" = %p", local);
310	return local;
311
312nomem:
313	ret = -ENOMEM;
314sock_error:
315	mutex_unlock(&rxnet->local_mutex);
316	if (local)
317		call_rcu(&local->rcu, rxrpc_local_rcu);
318	_leave(" = %d", ret);
319	return ERR_PTR(ret);
320
321addr_in_use:
322	mutex_unlock(&rxnet->local_mutex);
323	_leave(" = -EADDRINUSE");
324	return ERR_PTR(-EADDRINUSE);
325}
326
327/*
328 * Get a ref on a local endpoint.
329 */
330struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local,
331				    enum rxrpc_local_trace why)
332{
333	int r, u;
334
335	u = atomic_read(&local->active_users);
336	__refcount_inc(&local->ref, &r);
337	trace_rxrpc_local(local->debug_id, why, r + 1, u);
338	return local;
339}
340
341/*
342 * Get a ref on a local endpoint unless its usage has already reached 0.
343 */
344struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local,
345					  enum rxrpc_local_trace why)
346{
347	int r, u;
348
349	if (local && __refcount_inc_not_zero(&local->ref, &r)) {
350		u = atomic_read(&local->active_users);
351		trace_rxrpc_local(local->debug_id, why, r + 1, u);
352		return local;
353	}
354
355	return NULL;
356}
357
358/*
359 * Drop a ref on a local endpoint.
360 */
361void rxrpc_put_local(struct rxrpc_local *local, enum rxrpc_local_trace why)
362{
363	unsigned int debug_id;
364	bool dead;
365	int r, u;
366
367	if (local) {
368		debug_id = local->debug_id;
369
370		u = atomic_read(&local->active_users);
371		dead = __refcount_dec_and_test(&local->ref, &r);
372		trace_rxrpc_local(debug_id, why, r, u);
373
374		if (dead)
375			call_rcu(&local->rcu, rxrpc_local_rcu);
376	}
377}
378
379/*
380 * Start using a local endpoint.
381 */
382struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local,
383				    enum rxrpc_local_trace why)
384{
385	local = rxrpc_get_local_maybe(local, rxrpc_local_get_for_use);
386	if (!local)
387		return NULL;
388
389	if (!__rxrpc_use_local(local, why)) {
390		rxrpc_put_local(local, rxrpc_local_put_for_use);
391		return NULL;
392	}
393
394	return local;
395}
396
397/*
398 * Cease using a local endpoint.  Once the number of active users reaches 0, we
399 * start the closure of the transport in the I/O thread..
400 */
401void rxrpc_unuse_local(struct rxrpc_local *local, enum rxrpc_local_trace why)
402{
403	unsigned int debug_id;
404	int r, u;
405
406	if (local) {
407		debug_id = local->debug_id;
408		r = refcount_read(&local->ref);
409		u = atomic_dec_return(&local->active_users);
410		trace_rxrpc_local(debug_id, why, r, u);
411		if (u == 0)
412			kthread_stop(local->io_thread);
413	}
414}
415
416/*
417 * Destroy a local endpoint's socket and then hand the record to RCU to dispose
418 * of.
419 *
420 * Closing the socket cannot be done from bottom half context or RCU callback
421 * context because it might sleep.
422 */
423void rxrpc_destroy_local(struct rxrpc_local *local)
424{
425	struct socket *socket = local->socket;
426	struct rxrpc_net *rxnet = local->rxnet;
427
428	_enter("%d", local->debug_id);
429
430	local->dead = true;
431
432	mutex_lock(&rxnet->local_mutex);
433	hlist_del_init_rcu(&local->link);
434	mutex_unlock(&rxnet->local_mutex);
435
436	rxrpc_clean_up_local_conns(local);
437	rxrpc_service_connection_reaper(&rxnet->service_conn_reaper);
438	ASSERT(!local->service);
439
440	if (socket) {
441		local->socket = NULL;
442		kernel_sock_shutdown(socket, SHUT_RDWR);
443		socket->sk->sk_user_data = NULL;
444		sock_release(socket);
445	}
446
447	/* At this point, there should be no more packets coming in to the
448	 * local endpoint.
449	 */
450#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
451	rxrpc_purge_queue(&local->rx_delay_queue);
452#endif
453	rxrpc_purge_queue(&local->rx_queue);
454	rxrpc_purge_client_connections(local);
455	if (local->tx_alloc.va)
456		__page_frag_cache_drain(virt_to_page(local->tx_alloc.va),
457					local->tx_alloc.pagecnt_bias);
458}
459
460/*
461 * Destroy a local endpoint after the RCU grace period expires.
462 */
463static void rxrpc_local_rcu(struct rcu_head *rcu)
464{
465	struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
466
467	rxrpc_see_local(local, rxrpc_local_free);
468	kfree(local);
469}
470
471/*
472 * Verify the local endpoint list is empty by this point.
473 */
474void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
475{
476	struct rxrpc_local *local;
477
478	_enter("");
479
480	flush_workqueue(rxrpc_workqueue);
481
482	if (!hlist_empty(&rxnet->local_endpoints)) {
483		mutex_lock(&rxnet->local_mutex);
484		hlist_for_each_entry(local, &rxnet->local_endpoints, link) {
485			pr_err("AF_RXRPC: Leaked local %p {%d}\n",
486			       local, refcount_read(&local->ref));
487		}
488		mutex_unlock(&rxnet->local_mutex);
489		BUG();
490	}
491}
492