local_object.c

  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		break;
219
220	default:
221		BUG();
222	}
223
224	io_thread = kthread_run(rxrpc_io_thread, local,
225				"krxrpcio/%u", ntohs(udp_conf.local_udp_port));
226	if (IS_ERR(io_thread)) {
227		ret = PTR_ERR(io_thread);
228		goto error_sock;
229	}
230
231	wait_for_completion(&local->io_thread_ready);
232	WRITE_ONCE(local->io_thread, io_thread);
233	_leave(" = 0");
234	return 0;
235
236error_sock:
237	kernel_sock_shutdown(local->socket, SHUT_RDWR);
238	local->socket->sk->sk_user_data = NULL;
239	sock_release(local->socket);
240	local->socket = NULL;
241	return ret;
242}
243
244/*
245 * Look up or create a new local endpoint using the specified local address.
246 */
247struct rxrpc_local *rxrpc_lookup_local(struct net *net,
248				       const struct sockaddr_rxrpc *srx)
249{
250	struct rxrpc_local *local;
251	struct rxrpc_net *rxnet = rxrpc_net(net);
252	struct hlist_node *cursor;
253	long diff;
254	int ret;
255
256	_enter("{%d,%d,%pISp}",
257	       srx->transport_type, srx->transport.family, &srx->transport);
258
259	mutex_lock(&rxnet->local_mutex);
260
261	hlist_for_each(cursor, &rxnet->local_endpoints) {
262		local = hlist_entry(cursor, struct rxrpc_local, link);
263
264		diff = rxrpc_local_cmp_key(local, srx);
265		if (diff != 0)
266			continue;
267
268		/* Services aren't allowed to share transport sockets, so
269		 * reject that here.  It is possible that the object is dying -
270		 * but it may also still have the local transport address that
271		 * we want bound.
272		 */
273		if (srx->srx_service) {
274			local = NULL;
275			goto addr_in_use;
276		}
277
278		/* Found a match.  We want to replace a dying object.
279		 * Attempting to bind the transport socket may still fail if
280		 * we're attempting to use a local address that the dying
281		 * object is still using.
282		 */
283		if (!rxrpc_use_local(local, rxrpc_local_use_lookup))
284			break;
285
286		goto found;
287	}
288
289	local = rxrpc_alloc_local(net, srx);
290	if (!local)
291		goto nomem;
292
293	ret = rxrpc_open_socket(local, net);
294	if (ret < 0)
295		goto sock_error;
296
297	if (cursor) {
298		hlist_replace_rcu(cursor, &local->link);
299		cursor->pprev = NULL;
300	} else {
301		hlist_add_head_rcu(&local->link, &rxnet->local_endpoints);
302	}
303
304found:
305	mutex_unlock(&rxnet->local_mutex);
306	_leave(" = %p", local);
307	return local;
308
309nomem:
310	ret = -ENOMEM;
311sock_error:
312	mutex_unlock(&rxnet->local_mutex);
313	if (local)
314		call_rcu(&local->rcu, rxrpc_local_rcu);
315	_leave(" = %d", ret);
316	return ERR_PTR(ret);
317
318addr_in_use:
319	mutex_unlock(&rxnet->local_mutex);
320	_leave(" = -EADDRINUSE");
321	return ERR_PTR(-EADDRINUSE);
322}
323
324/*
325 * Get a ref on a local endpoint.
326 */
327struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local,
328				    enum rxrpc_local_trace why)
329{
330	int r, u;
331
332	u = atomic_read(&local->active_users);
333	__refcount_inc(&local->ref, &r);
334	trace_rxrpc_local(local->debug_id, why, r + 1, u);
335	return local;
336}
337
338/*
339 * Get a ref on a local endpoint unless its usage has already reached 0.
340 */
341struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local,
342					  enum rxrpc_local_trace why)
343{
344	int r, u;
345
346	if (local && __refcount_inc_not_zero(&local->ref, &r)) {
347		u = atomic_read(&local->active_users);
348		trace_rxrpc_local(local->debug_id, why, r + 1, u);
349		return local;
350	}
351
352	return NULL;
353}
354
355/*
356 * Drop a ref on a local endpoint.
357 */
358void rxrpc_put_local(struct rxrpc_local *local, enum rxrpc_local_trace why)
359{
360	unsigned int debug_id;
361	bool dead;
362	int r, u;
363
364	if (local) {
365		debug_id = local->debug_id;
366
367		u = atomic_read(&local->active_users);
368		dead = __refcount_dec_and_test(&local->ref, &r);
369		trace_rxrpc_local(debug_id, why, r, u);
370
371		if (dead)
372			call_rcu(&local->rcu, rxrpc_local_rcu);
373	}
374}
375
376/*
377 * Start using a local endpoint.
378 */
379struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local,
380				    enum rxrpc_local_trace why)
381{
382	local = rxrpc_get_local_maybe(local, rxrpc_local_get_for_use);
383	if (!local)
384		return NULL;
385
386	if (!__rxrpc_use_local(local, why)) {
387		rxrpc_put_local(local, rxrpc_local_put_for_use);
388		return NULL;
389	}
390
391	return local;
392}
393
394/*
395 * Cease using a local endpoint.  Once the number of active users reaches 0, we
396 * start the closure of the transport in the I/O thread..
397 */
398void rxrpc_unuse_local(struct rxrpc_local *local, enum rxrpc_local_trace why)
399{
400	unsigned int debug_id;
401	int r, u;
402
403	if (local) {
404		debug_id = local->debug_id;
405		r = refcount_read(&local->ref);
406		u = atomic_dec_return(&local->active_users);
407		trace_rxrpc_local(debug_id, why, r, u);
408		if (u == 0)
409			kthread_stop(local->io_thread);
410	}
411}
412
413/*
414 * Destroy a local endpoint's socket and then hand the record to RCU to dispose
415 * of.
416 *
417 * Closing the socket cannot be done from bottom half context or RCU callback
418 * context because it might sleep.
419 */
420void rxrpc_destroy_local(struct rxrpc_local *local)
421{
422	struct socket *socket = local->socket;
423	struct rxrpc_net *rxnet = local->rxnet;
424
425	_enter("%d", local->debug_id);
426
427	local->dead = true;
428
429	mutex_lock(&rxnet->local_mutex);
430	hlist_del_init_rcu(&local->link);
431	mutex_unlock(&rxnet->local_mutex);
432
433	rxrpc_clean_up_local_conns(local);
434	rxrpc_service_connection_reaper(&rxnet->service_conn_reaper);
435	ASSERT(!local->service);
436
437	if (socket) {
438		local->socket = NULL;
439		kernel_sock_shutdown(socket, SHUT_RDWR);
440		socket->sk->sk_user_data = NULL;
441		sock_release(socket);
442	}
443
444	/* At this point, there should be no more packets coming in to the
445	 * local endpoint.
446	 */
447#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
448	rxrpc_purge_queue(&local->rx_delay_queue);
449#endif
450	rxrpc_purge_queue(&local->rx_queue);
451	rxrpc_purge_client_connections(local);
452	page_frag_cache_drain(&local->tx_alloc);
453}
454
455/*
456 * Destroy a local endpoint after the RCU grace period expires.
457 */
458static void rxrpc_local_rcu(struct rcu_head *rcu)
459{
460	struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
461
462	rxrpc_see_local(local, rxrpc_local_free);
463	kfree(local);
464}
465
466/*
467 * Verify the local endpoint list is empty by this point.
468 */
469void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
470{
471	struct rxrpc_local *local;
472
473	_enter("");
474
475	flush_workqueue(rxrpc_workqueue);
476
477	if (!hlist_empty(&rxnet->local_endpoints)) {
478		mutex_lock(&rxnet->local_mutex);
479		hlist_for_each_entry(local, &rxnet->local_endpoints, link) {
480			pr_err("AF_RXRPC: Leaked local %p {%d}\n",
481			       local, refcount_read(&local->ref));
482		}
483		mutex_unlock(&rxnet->local_mutex);
484		BUG();
485	}
486}