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 conn->peer->last_tx_at = ktime_get_seconds();
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 int ret;
251
252 if (conn->state == RXRPC_CONN_ABORTED)
253 return -ECONNABORTED;
254
255 _enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
256
257 switch (sp->hdr.type) {
258 case RXRPC_PACKET_TYPE_CHALLENGE:
259 ret = conn->security->respond_to_challenge(conn, skb);
260 sp->chall.conn = NULL;
261 rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
262 return ret;
263
264 case RXRPC_PACKET_TYPE_RESPONSE:
265 ret = conn->security->verify_response(conn, skb);
266 if (ret < 0)
267 return ret;
268
269 ret = conn->security->init_connection_security(
270 conn, conn->key->payload.data[0]);
271 if (ret < 0)
272 return ret;
273
274 spin_lock_irq(&conn->state_lock);
275 if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING)
276 conn->state = RXRPC_CONN_SERVICE;
277 spin_unlock_irq(&conn->state_lock);
278
279 if (conn->state == RXRPC_CONN_SERVICE) {
280 /* Offload call state flipping to the I/O thread. As
281 * we've already received the packet, put it on the
282 * front of the queue.
283 */
284 sp->poke_conn = rxrpc_get_connection(
285 conn, rxrpc_conn_get_poke_secured);
286 skb->mark = RXRPC_SKB_MARK_SERVICE_CONN_SECURED;
287 rxrpc_get_skb(skb, rxrpc_skb_get_conn_secured);
288 skb_queue_head(&conn->local->rx_queue, skb);
289 rxrpc_wake_up_io_thread(conn->local);
290 }
291 return 0;
292
293 default:
294 WARN_ON_ONCE(1);
295 return -EPROTO;
296 }
297 }
298
299 /*
300 * set up security and issue a challenge
301 */
rxrpc_secure_connection(struct rxrpc_connection * conn)302 static void rxrpc_secure_connection(struct rxrpc_connection *conn)
303 {
304 if (conn->security->issue_challenge(conn) < 0)
305 rxrpc_abort_conn(conn, NULL, RX_CALL_DEAD, -ENOMEM,
306 rxrpc_abort_nomem);
307 }
308
309 /*
310 * Process delayed final ACKs that we haven't subsumed into a subsequent call.
311 */
rxrpc_process_delayed_final_acks(struct rxrpc_connection * conn,bool force)312 void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn, bool force)
313 {
314 unsigned long j = jiffies, next_j;
315 unsigned int channel;
316 bool set;
317
318 again:
319 next_j = j + LONG_MAX;
320 set = false;
321 for (channel = 0; channel < RXRPC_MAXCALLS; channel++) {
322 struct rxrpc_channel *chan = &conn->channels[channel];
323 unsigned long ack_at;
324
325 if (!test_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags))
326 continue;
327
328 ack_at = chan->final_ack_at;
329 if (time_before(j, ack_at) && !force) {
330 if (time_before(ack_at, next_j)) {
331 next_j = ack_at;
332 set = true;
333 }
334 continue;
335 }
336
337 if (test_and_clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel,
338 &conn->flags))
339 rxrpc_conn_retransmit_call(conn, NULL, channel);
340 }
341
342 j = jiffies;
343 if (time_before_eq(next_j, j))
344 goto again;
345 if (set)
346 rxrpc_reduce_conn_timer(conn, next_j);
347 }
348
349 /*
350 * connection-level event processor
351 */
rxrpc_do_process_connection(struct rxrpc_connection * conn)352 static void rxrpc_do_process_connection(struct rxrpc_connection *conn)
353 {
354 struct sk_buff *skb;
355 int ret;
356
357 if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
358 rxrpc_secure_connection(conn);
359
360 /* go through the conn-level event packets, releasing the ref on this
361 * connection that each one has when we've finished with it */
362 while ((skb = skb_dequeue(&conn->rx_queue))) {
363 rxrpc_see_skb(skb, rxrpc_skb_see_conn_work);
364 ret = rxrpc_process_event(conn, skb);
365 switch (ret) {
366 case -ENOMEM:
367 case -EAGAIN:
368 skb_queue_head(&conn->rx_queue, skb);
369 rxrpc_queue_conn(conn, rxrpc_conn_queue_retry_work);
370 break;
371 default:
372 rxrpc_free_skb(skb, rxrpc_skb_put_conn_work);
373 break;
374 }
375 }
376 }
377
rxrpc_process_connection(struct work_struct * work)378 void rxrpc_process_connection(struct work_struct *work)
379 {
380 struct rxrpc_connection *conn =
381 container_of(work, struct rxrpc_connection, processor);
382
383 rxrpc_see_connection(conn, rxrpc_conn_see_work);
384
385 if (__rxrpc_use_local(conn->local, rxrpc_local_use_conn_work)) {
386 rxrpc_do_process_connection(conn);
387 rxrpc_unuse_local(conn->local, rxrpc_local_unuse_conn_work);
388 }
389 }
390
391 /*
392 * post connection-level events to the connection
393 * - this includes challenges, responses, some aborts and call terminal packet
394 * retransmission.
395 */
rxrpc_post_packet_to_conn(struct rxrpc_connection * conn,struct sk_buff * skb)396 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
397 struct sk_buff *skb)
398 {
399 _enter("%p,%p", conn, skb);
400
401 rxrpc_get_skb(skb, rxrpc_skb_get_conn_work);
402 skb_queue_tail(&conn->rx_queue, skb);
403 rxrpc_queue_conn(conn, rxrpc_conn_queue_rx_work);
404 }
405
406 /*
407 * Post a CHALLENGE packet to the socket of one of a connection's calls so that
408 * it can get application data to include in the packet, possibly querying
409 * userspace.
410 */
rxrpc_post_challenge(struct rxrpc_connection * conn,struct sk_buff * skb)411 static bool rxrpc_post_challenge(struct rxrpc_connection *conn,
412 struct sk_buff *skb)
413 {
414 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
415 struct rxrpc_call *call = NULL;
416 struct rxrpc_sock *rx;
417 bool respond = false;
418
419 sp->chall.conn =
420 rxrpc_get_connection(conn, rxrpc_conn_get_challenge_input);
421
422 if (!conn->security->challenge_to_recvmsg) {
423 rxrpc_post_packet_to_conn(conn, skb);
424 return true;
425 }
426
427 rcu_read_lock();
428
429 for (int i = 0; i < ARRAY_SIZE(conn->channels); i++) {
430 if (conn->channels[i].call) {
431 call = conn->channels[i].call;
432 rx = rcu_dereference(call->socket);
433 if (!rx) {
434 call = NULL;
435 continue;
436 }
437
438 respond = true;
439 if (test_bit(RXRPC_SOCK_MANAGE_RESPONSE, &rx->flags))
440 break;
441 call = NULL;
442 }
443 }
444
445 if (!respond) {
446 rcu_read_unlock();
447 rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
448 sp->chall.conn = NULL;
449 return false;
450 }
451
452 if (call)
453 rxrpc_notify_socket_oob(call, skb);
454 rcu_read_unlock();
455
456 if (!call)
457 rxrpc_post_packet_to_conn(conn, skb);
458 return true;
459 }
460
461 /*
462 * Input a connection-level packet.
463 */
rxrpc_input_conn_packet(struct rxrpc_connection * conn,struct sk_buff * skb)464 bool rxrpc_input_conn_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
465 {
466 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
467
468 switch (sp->hdr.type) {
469 case RXRPC_PACKET_TYPE_BUSY:
470 /* Just ignore BUSY packets for now. */
471 return true;
472
473 case RXRPC_PACKET_TYPE_ABORT:
474 if (rxrpc_is_conn_aborted(conn))
475 return true;
476 rxrpc_input_conn_abort(conn, skb);
477 rxrpc_abort_calls(conn);
478 return true;
479
480 case RXRPC_PACKET_TYPE_CHALLENGE:
481 rxrpc_see_skb(skb, rxrpc_skb_see_oob_challenge);
482 if (rxrpc_is_conn_aborted(conn)) {
483 if (conn->completion == RXRPC_CALL_LOCALLY_ABORTED)
484 rxrpc_send_conn_abort(conn);
485 return true;
486 }
487 if (!conn->security->validate_challenge(conn, skb))
488 return false;
489 return rxrpc_post_challenge(conn, skb);
490
491 case RXRPC_PACKET_TYPE_RESPONSE:
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 rxrpc_post_packet_to_conn(conn, skb);
498 return true;
499
500 default:
501 WARN_ON_ONCE(1);
502 return true;
503 }
504 }
505
506 /*
507 * Input a connection event.
508 */
rxrpc_input_conn_event(struct rxrpc_connection * conn,struct sk_buff * skb)509 void rxrpc_input_conn_event(struct rxrpc_connection *conn, struct sk_buff *skb)
510 {
511 unsigned int loop;
512
513 if (test_and_clear_bit(RXRPC_CONN_EV_ABORT_CALLS, &conn->events))
514 rxrpc_abort_calls(conn);
515
516 if (conn->tx_response) {
517 struct sk_buff *skb;
518
519 spin_lock_irq(&conn->local->lock);
520 skb = conn->tx_response;
521 conn->tx_response = NULL;
522 spin_unlock_irq(&conn->local->lock);
523
524 if (conn->state != RXRPC_CONN_ABORTED)
525 rxrpc_send_response(conn, skb);
526 rxrpc_free_skb(skb, rxrpc_skb_put_response);
527 }
528
529 if (skb) {
530 switch (skb->mark) {
531 case RXRPC_SKB_MARK_SERVICE_CONN_SECURED:
532 if (conn->state != RXRPC_CONN_SERVICE)
533 break;
534
535 for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
536 rxrpc_call_is_secure(conn->channels[loop].call);
537 break;
538 }
539 }
540
541 /* Process delayed ACKs whose time has come. */
542 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
543 rxrpc_process_delayed_final_acks(conn, false);
544 }
545
546 /*
547 * Post a RESPONSE message to the I/O thread for transmission.
548 */
rxrpc_post_response(struct rxrpc_connection * conn,struct sk_buff * skb)549 void rxrpc_post_response(struct rxrpc_connection *conn, struct sk_buff *skb)
550 {
551 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
552 struct rxrpc_local *local = conn->local;
553 struct sk_buff *old;
554
555 _enter("%x", sp->resp.challenge_serial);
556
557 spin_lock_irq(&local->lock);
558 old = conn->tx_response;
559 if (old) {
560 struct rxrpc_skb_priv *osp = rxrpc_skb(skb);
561
562 /* Always go with the response to the most recent challenge. */
563 if (after(sp->resp.challenge_serial, osp->resp.challenge_serial))
564 conn->tx_response = old;
565 else
566 old = skb;
567 } else {
568 conn->tx_response = skb;
569 }
570 spin_unlock_irq(&local->lock);
571 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_response);
572 }
573