1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* connection-level event handling
3 *
4 * Copyright (C) 2007 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/errqueue.h>
14 #include <net/sock.h>
15 #include <net/af_rxrpc.h>
16 #include <net/ip.h>
17 #include "ar-internal.h"
18
19 /*
20 * Set the completion state on an aborted connection.
21 */
rxrpc_set_conn_aborted(struct rxrpc_connection * conn,s32 abort_code,int err,enum rxrpc_call_completion compl)22 static bool rxrpc_set_conn_aborted(struct rxrpc_connection *conn,
23 s32 abort_code, int err,
24 enum rxrpc_call_completion compl)
25 {
26 bool aborted = false;
27
28 if (conn->state != RXRPC_CONN_ABORTED) {
29 spin_lock_irq(&conn->state_lock);
30 if (conn->state != RXRPC_CONN_ABORTED) {
31 conn->abort_code = abort_code;
32 conn->error = err;
33 conn->completion = compl;
34 /* Order the abort info before the state change. */
35 smp_store_release(&conn->state, RXRPC_CONN_ABORTED);
36 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
37 set_bit(RXRPC_CONN_EV_ABORT_CALLS, &conn->events);
38 aborted = true;
39 }
40 spin_unlock_irq(&conn->state_lock);
41 }
42
43 return aborted;
44 }
45
46 /*
47 * Mark a socket buffer to indicate that the connection it's on should be aborted.
48 */
rxrpc_abort_conn(struct rxrpc_connection * conn,struct sk_buff * skb,s32 abort_code,int err,enum rxrpc_abort_reason why)49 int rxrpc_abort_conn(struct rxrpc_connection *conn, struct sk_buff *skb,
50 s32 abort_code, int err, enum rxrpc_abort_reason why)
51 {
52
53 u32 cid = conn->proto.cid, call = 0, seq = 0;
54
55 if (skb) {
56 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
57
58 cid = sp->hdr.cid;
59 call = sp->hdr.callNumber;
60 seq = sp->hdr.seq;
61 }
62
63 if (rxrpc_set_conn_aborted(conn, abort_code, err,
64 RXRPC_CALL_LOCALLY_ABORTED)) {
65 trace_rxrpc_abort(0, why, cid, call, seq, abort_code, err);
66 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_abort);
67 }
68 return -EPROTO;
69 }
70
71 /*
72 * Mark a connection as being remotely aborted.
73 */
rxrpc_input_conn_abort(struct rxrpc_connection * conn,struct sk_buff * skb)74 static void rxrpc_input_conn_abort(struct rxrpc_connection *conn,
75 struct sk_buff *skb)
76 {
77 trace_rxrpc_rx_conn_abort(conn, skb);
78 rxrpc_set_conn_aborted(conn, skb->priority, -ECONNABORTED,
79 RXRPC_CALL_REMOTELY_ABORTED);
80 }
81
82 /*
83 * Retransmit terminal ACK or ABORT of the previous call.
84 */
rxrpc_conn_retransmit_call(struct rxrpc_connection * conn,struct sk_buff * skb,unsigned int channel)85 void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
86 struct sk_buff *skb,
87 unsigned int channel)
88 {
89 struct rxrpc_skb_priv *sp = skb ? rxrpc_skb(skb) : NULL;
90 struct rxrpc_channel *chan;
91 struct msghdr msg;
92 struct kvec iov[3];
93 struct {
94 struct rxrpc_wire_header whdr;
95 union {
96 __be32 abort_code;
97 struct rxrpc_ackpacket ack;
98 };
99 } __attribute__((packed)) pkt;
100 struct rxrpc_acktrailer trailer;
101 size_t len;
102 int ret, ioc;
103 u32 serial, max_mtu, if_mtu, call_id, padding;
104
105 _enter("%d", conn->debug_id);
106
107 if (sp && sp->hdr.type == RXRPC_PACKET_TYPE_ACK) {
108 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
109 &pkt.ack, sizeof(pkt.ack)) < 0)
110 return;
111 if (pkt.ack.reason == RXRPC_ACK_PING_RESPONSE)
112 return;
113 }
114
115 chan = &conn->channels[channel];
116
117 /* If the last call got moved on whilst we were waiting to run, just
118 * ignore this packet.
119 */
120 call_id = chan->last_call;
121 if (skb && call_id != sp->hdr.callNumber)
122 return;
123
124 msg.msg_name = &conn->peer->srx.transport;
125 msg.msg_namelen = conn->peer->srx.transport_len;
126 msg.msg_control = NULL;
127 msg.msg_controllen = 0;
128 msg.msg_flags = 0;
129
130 iov[0].iov_base = &pkt;
131 iov[0].iov_len = sizeof(pkt.whdr);
132 iov[1].iov_base = &padding;
133 iov[1].iov_len = 3;
134 iov[2].iov_base = &trailer;
135 iov[2].iov_len = sizeof(trailer);
136
137 serial = rxrpc_get_next_serial(conn);
138
139 pkt.whdr.epoch = htonl(conn->proto.epoch);
140 pkt.whdr.cid = htonl(conn->proto.cid | channel);
141 pkt.whdr.callNumber = htonl(call_id);
142 pkt.whdr.serial = htonl(serial);
143 pkt.whdr.seq = 0;
144 pkt.whdr.type = chan->last_type;
145 pkt.whdr.flags = conn->out_clientflag;
146 pkt.whdr.userStatus = 0;
147 pkt.whdr.securityIndex = conn->security_ix;
148 pkt.whdr._rsvd = 0;
149 pkt.whdr.serviceId = htons(conn->service_id);
150
151 len = sizeof(pkt.whdr);
152 switch (chan->last_type) {
153 case RXRPC_PACKET_TYPE_ABORT:
154 pkt.abort_code = htonl(chan->last_abort);
155 iov[0].iov_len += sizeof(pkt.abort_code);
156 len += sizeof(pkt.abort_code);
157 ioc = 1;
158 break;
159
160 case RXRPC_PACKET_TYPE_ACK:
161 if_mtu = conn->peer->if_mtu - conn->peer->hdrsize;
162 if (conn->peer->ackr_adv_pmtud) {
163 max_mtu = umax(conn->peer->max_data, rxrpc_rx_mtu);
164 } else {
165 if_mtu = umin(1444, if_mtu);
166 max_mtu = if_mtu;
167 }
168 pkt.ack.bufferSpace = 0;
169 pkt.ack.maxSkew = htons(skb ? skb->priority : 0);
170 pkt.ack.firstPacket = htonl(chan->last_seq + 1);
171 pkt.ack.previousPacket = htonl(chan->last_seq);
172 pkt.ack.serial = htonl(skb ? sp->hdr.serial : 0);
173 pkt.ack.reason = skb ? RXRPC_ACK_DUPLICATE : RXRPC_ACK_IDLE;
174 pkt.ack.nAcks = 0;
175 trailer.maxMTU = htonl(max_mtu);
176 trailer.ifMTU = htonl(if_mtu);
177 trailer.rwind = htonl(rxrpc_rx_window_size);
178 trailer.jumbo_max = 0;
179 pkt.whdr.flags |= RXRPC_SLOW_START_OK;
180 padding = 0;
181 iov[0].iov_len += sizeof(pkt.ack);
182 len += sizeof(pkt.ack) + 3 + sizeof(trailer);
183 ioc = 3;
184
185 trace_rxrpc_tx_ack(chan->call_debug_id, serial,
186 ntohl(pkt.ack.firstPacket),
187 ntohl(pkt.ack.serial),
188 pkt.ack.reason, 0, rxrpc_rx_window_size,
189 rxrpc_propose_ack_retransmit);
190 break;
191
192 default:
193 return;
194 }
195
196 ret = kernel_sendmsg(conn->local->socket, &msg, iov, ioc, len);
197 rxrpc_peer_mark_tx(conn->peer);
198 if (ret < 0)
199 trace_rxrpc_tx_fail(chan->call_debug_id, serial, ret,
200 rxrpc_tx_point_call_final_resend);
201 else
202 trace_rxrpc_tx_packet(chan->call_debug_id, &pkt.whdr,
203 rxrpc_tx_point_call_final_resend);
204
205 _leave("");
206 }
207
208 /*
209 * pass a connection-level abort onto all calls on that connection
210 */
rxrpc_abort_calls(struct rxrpc_connection * conn)211 static void rxrpc_abort_calls(struct rxrpc_connection *conn)
212 {
213 struct rxrpc_call *call;
214 int i;
215
216 _enter("{%d},%x", conn->debug_id, conn->abort_code);
217
218 for (i = 0; i < RXRPC_MAXCALLS; i++) {
219 call = conn->channels[i].call;
220 if (call) {
221 rxrpc_see_call(call, rxrpc_call_see_conn_abort);
222 rxrpc_set_call_completion(call,
223 conn->completion,
224 conn->abort_code,
225 conn->error);
226 rxrpc_poke_call(call, rxrpc_call_poke_conn_abort);
227 }
228 }
229
230 _leave("");
231 }
232
233 /*
234 * mark a call as being on a now-secured channel
235 * - must be called with BH's disabled.
236 */
rxrpc_call_is_secure(struct rxrpc_call * call)237 static void rxrpc_call_is_secure(struct rxrpc_call *call)
238 {
239 if (call && __test_and_clear_bit(RXRPC_CALL_CONN_CHALLENGING, &call->flags))
240 rxrpc_notify_socket(call);
241 }
242
243 /*
244 * connection-level Rx packet processor
245 */
rxrpc_process_event(struct rxrpc_connection * conn,struct sk_buff * skb)246 static int rxrpc_process_event(struct rxrpc_connection *conn,
247 struct sk_buff *skb)
248 {
249 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
250 bool secured = false;
251 int ret;
252
253 if (conn->state == RXRPC_CONN_ABORTED)
254 return -ECONNABORTED;
255
256 _enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
257
258 switch (sp->hdr.type) {
259 case RXRPC_PACKET_TYPE_CHALLENGE:
260 ret = conn->security->respond_to_challenge(conn, skb);
261 sp->chall.conn = NULL;
262 rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
263 return ret;
264
265 case RXRPC_PACKET_TYPE_RESPONSE:
266 spin_lock_irq(&conn->state_lock);
267 if (conn->state != RXRPC_CONN_SERVICE_CHALLENGING) {
268 spin_unlock_irq(&conn->state_lock);
269 return 0;
270 }
271 spin_unlock_irq(&conn->state_lock);
272
273 ret = conn->security->verify_response(conn, skb);
274 if (ret < 0)
275 return ret;
276
277 ret = conn->security->init_connection_security(
278 conn, conn->key->payload.data[0]);
279 if (ret < 0)
280 return ret;
281
282 spin_lock_irq(&conn->state_lock);
283 if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
284 conn->state = RXRPC_CONN_SERVICE;
285 secured = true;
286 }
287 spin_unlock_irq(&conn->state_lock);
288
289 if (secured) {
290 /* Offload call state flipping to the I/O thread. As
291 * we've already received the packet, put it on the
292 * front of the queue.
293 */
294 sp->poke_conn = rxrpc_get_connection(
295 conn, rxrpc_conn_get_poke_secured);
296 skb->mark = RXRPC_SKB_MARK_SERVICE_CONN_SECURED;
297 rxrpc_get_skb(skb, rxrpc_skb_get_conn_secured);
298 skb_queue_head(&conn->local->rx_queue, skb);
299 rxrpc_wake_up_io_thread(conn->local);
300 }
301 return 0;
302
303 default:
304 WARN_ON_ONCE(1);
305 return -EPROTO;
306 }
307 }
308
309 /*
310 * set up security and issue a challenge
311 */
rxrpc_secure_connection(struct rxrpc_connection * conn)312 static void rxrpc_secure_connection(struct rxrpc_connection *conn)
313 {
314 if (conn->security->issue_challenge(conn) < 0)
315 rxrpc_abort_conn(conn, NULL, RX_CALL_DEAD, -ENOMEM,
316 rxrpc_abort_nomem);
317 }
318
319 /*
320 * Process delayed final ACKs that we haven't subsumed into a subsequent call.
321 */
rxrpc_process_delayed_final_acks(struct rxrpc_connection * conn,bool force)322 void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn, bool force)
323 {
324 unsigned long j = jiffies, next_j;
325 unsigned int channel;
326 bool set;
327
328 again:
329 next_j = j + LONG_MAX;
330 set = false;
331 for (channel = 0; channel < RXRPC_MAXCALLS; channel++) {
332 struct rxrpc_channel *chan = &conn->channels[channel];
333 unsigned long ack_at;
334
335 if (!test_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags))
336 continue;
337
338 ack_at = chan->final_ack_at;
339 if (time_before(j, ack_at) && !force) {
340 if (time_before(ack_at, next_j)) {
341 next_j = ack_at;
342 set = true;
343 }
344 continue;
345 }
346
347 if (test_and_clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel,
348 &conn->flags))
349 rxrpc_conn_retransmit_call(conn, NULL, channel);
350 }
351
352 j = jiffies;
353 if (time_before_eq(next_j, j))
354 goto again;
355 if (set)
356 rxrpc_reduce_conn_timer(conn, next_j);
357 }
358
359 /*
360 * connection-level event processor
361 */
rxrpc_do_process_connection(struct rxrpc_connection * conn)362 static void rxrpc_do_process_connection(struct rxrpc_connection *conn)
363 {
364 struct sk_buff *skb;
365 int ret;
366
367 if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
368 rxrpc_secure_connection(conn);
369
370 /* go through the conn-level event packets, releasing the ref on this
371 * connection that each one has when we've finished with it */
372 while ((skb = skb_dequeue(&conn->rx_queue))) {
373 rxrpc_see_skb(skb, rxrpc_skb_see_conn_work);
374 ret = rxrpc_process_event(conn, skb);
375 switch (ret) {
376 case -ENOMEM:
377 case -EAGAIN:
378 skb_queue_head(&conn->rx_queue, skb);
379 rxrpc_queue_conn(conn, rxrpc_conn_queue_retry_work);
380 break;
381 default:
382 rxrpc_free_skb(skb, rxrpc_skb_put_conn_work);
383 break;
384 }
385 }
386 }
387
rxrpc_process_connection(struct work_struct * work)388 void rxrpc_process_connection(struct work_struct *work)
389 {
390 struct rxrpc_connection *conn =
391 container_of(work, struct rxrpc_connection, processor);
392
393 rxrpc_see_connection(conn, rxrpc_conn_see_work);
394
395 if (__rxrpc_use_local(conn->local, rxrpc_local_use_conn_work)) {
396 rxrpc_do_process_connection(conn);
397 rxrpc_unuse_local(conn->local, rxrpc_local_unuse_conn_work);
398 }
399 }
400
401 /*
402 * post connection-level events to the connection
403 * - this includes challenges, responses, some aborts and call terminal packet
404 * retransmission.
405 */
rxrpc_post_packet_to_conn(struct rxrpc_connection * conn,struct sk_buff * skb)406 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
407 struct sk_buff *skb)
408 {
409 _enter("%p,%p", conn, skb);
410
411 rxrpc_get_skb(skb, rxrpc_skb_get_conn_work);
412 skb_queue_tail(&conn->rx_queue, skb);
413 rxrpc_queue_conn(conn, rxrpc_conn_queue_rx_work);
414 }
415
416 /*
417 * Post a CHALLENGE packet to the socket of one of a connection's calls so that
418 * it can get application data to include in the packet, possibly querying
419 * userspace.
420 */
rxrpc_post_challenge(struct rxrpc_connection * conn,struct sk_buff * skb)421 static bool rxrpc_post_challenge(struct rxrpc_connection *conn,
422 struct sk_buff *skb)
423 {
424 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
425 struct rxrpc_call *call = NULL;
426 struct rxrpc_sock *rx;
427 bool respond = false;
428
429 sp->chall.conn =
430 rxrpc_get_connection(conn, rxrpc_conn_get_challenge_input);
431
432 if (!conn->security->challenge_to_recvmsg) {
433 rxrpc_post_packet_to_conn(conn, skb);
434 return true;
435 }
436
437 rcu_read_lock();
438
439 for (int i = 0; i < ARRAY_SIZE(conn->channels); i++) {
440 if (conn->channels[i].call) {
441 call = conn->channels[i].call;
442 rx = rcu_dereference(call->socket);
443 if (!rx) {
444 call = NULL;
445 continue;
446 }
447
448 respond = true;
449 if (test_bit(RXRPC_SOCK_MANAGE_RESPONSE, &rx->flags))
450 break;
451 call = NULL;
452 }
453 }
454
455 if (!respond) {
456 rcu_read_unlock();
457 rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
458 sp->chall.conn = NULL;
459 return false;
460 }
461
462 if (call)
463 rxrpc_notify_socket_oob(call, skb);
464 rcu_read_unlock();
465
466 if (!call)
467 rxrpc_post_packet_to_conn(conn, skb);
468 return true;
469 }
470
471 /*
472 * Input a connection-level packet.
473 */
rxrpc_input_conn_packet(struct rxrpc_connection * conn,struct sk_buff * skb)474 bool rxrpc_input_conn_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
475 {
476 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
477
478 switch (sp->hdr.type) {
479 case RXRPC_PACKET_TYPE_BUSY:
480 /* Just ignore BUSY packets for now. */
481 return true;
482
483 case RXRPC_PACKET_TYPE_ABORT:
484 if (rxrpc_is_conn_aborted(conn))
485 return true;
486 rxrpc_input_conn_abort(conn, skb);
487 rxrpc_abort_calls(conn);
488 return true;
489
490 case RXRPC_PACKET_TYPE_CHALLENGE:
491 rxrpc_see_skb(skb, rxrpc_skb_see_oob_challenge);
492 if (rxrpc_is_conn_aborted(conn)) {
493 if (conn->completion == RXRPC_CALL_LOCALLY_ABORTED)
494 rxrpc_send_conn_abort(conn);
495 return true;
496 }
497 if (!conn->security->validate_challenge(conn, skb))
498 return false;
499 return rxrpc_post_challenge(conn, skb);
500
501 case RXRPC_PACKET_TYPE_RESPONSE:
502 if (rxrpc_is_conn_aborted(conn)) {
503 if (conn->completion == RXRPC_CALL_LOCALLY_ABORTED)
504 rxrpc_send_conn_abort(conn);
505 return true;
506 }
507 rxrpc_post_packet_to_conn(conn, skb);
508 return true;
509
510 default:
511 WARN_ON_ONCE(1);
512 return true;
513 }
514 }
515
516 /*
517 * Input a connection event.
518 */
rxrpc_input_conn_event(struct rxrpc_connection * conn,struct sk_buff * skb)519 void rxrpc_input_conn_event(struct rxrpc_connection *conn, struct sk_buff *skb)
520 {
521 unsigned int loop;
522
523 if (test_and_clear_bit(RXRPC_CONN_EV_ABORT_CALLS, &conn->events))
524 rxrpc_abort_calls(conn);
525
526 if (conn->tx_response) {
527 struct sk_buff *skb;
528
529 spin_lock_irq(&conn->local->lock);
530 skb = conn->tx_response;
531 conn->tx_response = NULL;
532 spin_unlock_irq(&conn->local->lock);
533
534 if (conn->state != RXRPC_CONN_ABORTED)
535 rxrpc_send_response(conn, skb);
536 rxrpc_free_skb(skb, rxrpc_skb_put_response);
537 }
538
539 if (skb) {
540 switch (skb->mark) {
541 case RXRPC_SKB_MARK_SERVICE_CONN_SECURED:
542 if (conn->state != RXRPC_CONN_SERVICE)
543 break;
544
545 for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
546 rxrpc_call_is_secure(conn->channels[loop].call);
547 break;
548 }
549 }
550
551 /* Process delayed ACKs whose time has come. */
552 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
553 rxrpc_process_delayed_final_acks(conn, false);
554 }
555
556 /*
557 * Post a RESPONSE message to the I/O thread for transmission.
558 */
rxrpc_post_response(struct rxrpc_connection * conn,struct sk_buff * skb)559 void rxrpc_post_response(struct rxrpc_connection *conn, struct sk_buff *skb)
560 {
561 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
562 struct rxrpc_local *local = conn->local;
563 struct sk_buff *old;
564
565 _enter("%x", sp->resp.challenge_serial);
566
567 spin_lock_irq(&local->lock);
568 old = conn->tx_response;
569 if (old) {
570 struct rxrpc_skb_priv *osp = rxrpc_skb(old);
571
572 /* Always go with the response to the most recent challenge. */
573 if (after(sp->resp.challenge_serial, osp->resp.challenge_serial))
574 conn->tx_response = skb;
575 else
576 old = skb;
577 } else {
578 conn->tx_response = skb;
579 }
580 spin_unlock_irq(&local->lock);
581 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_response);
582 rxrpc_free_skb(old, rxrpc_skb_put_old_response);
583 }
584