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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* RxRPC packet transmission
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/net.h>
11#include <linux/gfp.h>
12#include <linux/skbuff.h>
13#include <linux/export.h>
14#include <net/sock.h>
15#include <net/af_rxrpc.h>
16#include <net/udp.h>
17#include "ar-internal.h"
18
19extern int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
20
21static ssize_t do_udp_sendmsg(struct socket *socket, struct msghdr *msg, size_t len)
22{
23 struct sockaddr *sa = msg->msg_name;
24 struct sock *sk = socket->sk;
25
26 if (IS_ENABLED(CONFIG_AF_RXRPC_IPV6)) {
27 if (sa->sa_family == AF_INET6) {
28 if (sk->sk_family != AF_INET6) {
29 pr_warn("AF_INET6 address on AF_INET socket\n");
30 return -ENOPROTOOPT;
31 }
32 return udpv6_sendmsg(sk, msg, len);
33 }
34 }
35 return udp_sendmsg(sk, msg, len);
36}
37
38struct rxrpc_abort_buffer {
39 struct rxrpc_wire_header whdr;
40 __be32 abort_code;
41};
42
43static const char rxrpc_keepalive_string[] = "";
44
45/*
46 * Increase Tx backoff on transmission failure and clear it on success.
47 */
48static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
49{
50 if (ret < 0) {
51 u16 tx_backoff = READ_ONCE(call->tx_backoff);
52
53 if (tx_backoff < HZ)
54 WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
55 } else {
56 WRITE_ONCE(call->tx_backoff, 0);
57 }
58}
59
60/*
61 * Arrange for a keepalive ping a certain time after we last transmitted. This
62 * lets the far side know we're still interested in this call and helps keep
63 * the route through any intervening firewall open.
64 *
65 * Receiving a response to the ping will prevent the ->expect_rx_by timer from
66 * expiring.
67 */
68static void rxrpc_set_keepalive(struct rxrpc_call *call)
69{
70 unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
71
72 keepalive_at += now;
73 WRITE_ONCE(call->keepalive_at, keepalive_at);
74 rxrpc_reduce_call_timer(call, keepalive_at, now,
75 rxrpc_timer_set_for_keepalive);
76}
77
78/*
79 * Fill out an ACK packet.
80 */
81static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
82 struct rxrpc_call *call,
83 struct rxrpc_txbuf *txb)
84{
85 struct rxrpc_ackinfo ackinfo;
86 unsigned int qsize;
87 rxrpc_seq_t window, wtop, wrap_point, ix, first;
88 int rsize;
89 u64 wtmp;
90 u32 mtu, jmax;
91 u8 *ackp = txb->acks;
92 u8 sack_buffer[sizeof(call->ackr_sack_table)] __aligned(8);
93
94 atomic_set(&call->ackr_nr_unacked, 0);
95 atomic_set(&call->ackr_nr_consumed, 0);
96 rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill);
97
98 /* Barrier against rxrpc_input_data(). */
99retry:
100 wtmp = atomic64_read_acquire(&call->ackr_window);
101 window = lower_32_bits(wtmp);
102 wtop = upper_32_bits(wtmp);
103 txb->ack.firstPacket = htonl(window);
104 txb->ack.nAcks = 0;
105
106 if (after(wtop, window)) {
107 /* Try to copy the SACK ring locklessly. We can use the copy,
108 * only if the now-current top of the window didn't go past the
109 * previously read base - otherwise we can't know whether we
110 * have old data or new data.
111 */
112 memcpy(sack_buffer, call->ackr_sack_table, sizeof(sack_buffer));
113 wrap_point = window + RXRPC_SACK_SIZE - 1;
114 wtmp = atomic64_read_acquire(&call->ackr_window);
115 window = lower_32_bits(wtmp);
116 wtop = upper_32_bits(wtmp);
117 if (after(wtop, wrap_point)) {
118 cond_resched();
119 goto retry;
120 }
121
122 /* The buffer is maintained as a ring with an invariant mapping
123 * between bit position and sequence number, so we'll probably
124 * need to rotate it.
125 */
126 txb->ack.nAcks = wtop - window;
127 ix = window % RXRPC_SACK_SIZE;
128 first = sizeof(sack_buffer) - ix;
129
130 if (ix + txb->ack.nAcks <= RXRPC_SACK_SIZE) {
131 memcpy(txb->acks, sack_buffer + ix, txb->ack.nAcks);
132 } else {
133 memcpy(txb->acks, sack_buffer + ix, first);
134 memcpy(txb->acks + first, sack_buffer,
135 txb->ack.nAcks - first);
136 }
137
138 ackp += txb->ack.nAcks;
139 } else if (before(wtop, window)) {
140 pr_warn("ack window backward %x %x", window, wtop);
141 } else if (txb->ack.reason == RXRPC_ACK_DELAY) {
142 txb->ack.reason = RXRPC_ACK_IDLE;
143 }
144
145 mtu = conn->peer->if_mtu;
146 mtu -= conn->peer->hdrsize;
147 jmax = rxrpc_rx_jumbo_max;
148 qsize = (window - 1) - call->rx_consumed;
149 rsize = max_t(int, call->rx_winsize - qsize, 0);
150 ackinfo.rxMTU = htonl(rxrpc_rx_mtu);
151 ackinfo.maxMTU = htonl(mtu);
152 ackinfo.rwind = htonl(rsize);
153 ackinfo.jumbo_max = htonl(jmax);
154
155 *ackp++ = 0;
156 *ackp++ = 0;
157 *ackp++ = 0;
158 memcpy(ackp, &ackinfo, sizeof(ackinfo));
159 return txb->ack.nAcks + 3 + sizeof(ackinfo);
160}
161
162/*
163 * Record the beginning of an RTT probe.
164 */
165static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
166 enum rxrpc_rtt_tx_trace why)
167{
168 unsigned long avail = call->rtt_avail;
169 int rtt_slot = 9;
170
171 if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
172 goto no_slot;
173
174 rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
175 if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
176 goto no_slot;
177
178 call->rtt_serial[rtt_slot] = serial;
179 call->rtt_sent_at[rtt_slot] = ktime_get_real();
180 smp_wmb(); /* Write data before avail bit */
181 set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
182
183 trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
184 return rtt_slot;
185
186no_slot:
187 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
188 return -1;
189}
190
191/*
192 * Cancel an RTT probe.
193 */
194static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call,
195 rxrpc_serial_t serial, int rtt_slot)
196{
197 if (rtt_slot != -1) {
198 clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
199 smp_wmb(); /* Clear pending bit before setting slot */
200 set_bit(rtt_slot, &call->rtt_avail);
201 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial);
202 }
203}
204
205/*
206 * Transmit an ACK packet.
207 */
208int rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
209{
210 struct rxrpc_connection *conn;
211 struct msghdr msg;
212 struct kvec iov[1];
213 rxrpc_serial_t serial;
214 size_t len, n;
215 int ret, rtt_slot = -1;
216
217 if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
218 return -ECONNRESET;
219
220 conn = call->conn;
221
222 msg.msg_name = &call->peer->srx.transport;
223 msg.msg_namelen = call->peer->srx.transport_len;
224 msg.msg_control = NULL;
225 msg.msg_controllen = 0;
226 msg.msg_flags = 0;
227
228 if (txb->ack.reason == RXRPC_ACK_PING)
229 txb->wire.flags |= RXRPC_REQUEST_ACK;
230
231 n = rxrpc_fill_out_ack(conn, call, txb);
232 if (n == 0)
233 return 0;
234
235 iov[0].iov_base = &txb->wire;
236 iov[0].iov_len = sizeof(txb->wire) + sizeof(txb->ack) + n;
237 len = iov[0].iov_len;
238
239 serial = atomic_inc_return(&conn->serial);
240 txb->wire.serial = htonl(serial);
241 trace_rxrpc_tx_ack(call->debug_id, serial,
242 ntohl(txb->ack.firstPacket),
243 ntohl(txb->ack.serial), txb->ack.reason, txb->ack.nAcks);
244
245 if (txb->ack.reason == RXRPC_ACK_PING)
246 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
247
248 rxrpc_inc_stat(call->rxnet, stat_tx_ack_send);
249
250 /* Grab the highest received seq as late as possible */
251 txb->ack.previousPacket = htonl(call->rx_highest_seq);
252
253 iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
254 ret = do_udp_sendmsg(conn->local->socket, &msg, len);
255 call->peer->last_tx_at = ktime_get_seconds();
256 if (ret < 0)
257 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
258 rxrpc_tx_point_call_ack);
259 else
260 trace_rxrpc_tx_packet(call->debug_id, &txb->wire,
261 rxrpc_tx_point_call_ack);
262 rxrpc_tx_backoff(call, ret);
263
264 if (!__rxrpc_call_is_complete(call)) {
265 if (ret < 0)
266 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
267 rxrpc_set_keepalive(call);
268 }
269
270 return ret;
271}
272
273/*
274 * Send an ABORT call packet.
275 */
276int rxrpc_send_abort_packet(struct rxrpc_call *call)
277{
278 struct rxrpc_connection *conn;
279 struct rxrpc_abort_buffer pkt;
280 struct msghdr msg;
281 struct kvec iov[1];
282 rxrpc_serial_t serial;
283 int ret;
284
285 /* Don't bother sending aborts for a client call once the server has
286 * hard-ACK'd all of its request data. After that point, we're not
287 * going to stop the operation proceeding, and whilst we might limit
288 * the reply, it's not worth it if we can send a new call on the same
289 * channel instead, thereby closing off this call.
290 */
291 if (rxrpc_is_client_call(call) &&
292 test_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags))
293 return 0;
294
295 if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
296 return -ECONNRESET;
297
298 conn = call->conn;
299
300 msg.msg_name = &call->peer->srx.transport;
301 msg.msg_namelen = call->peer->srx.transport_len;
302 msg.msg_control = NULL;
303 msg.msg_controllen = 0;
304 msg.msg_flags = 0;
305
306 pkt.whdr.epoch = htonl(conn->proto.epoch);
307 pkt.whdr.cid = htonl(call->cid);
308 pkt.whdr.callNumber = htonl(call->call_id);
309 pkt.whdr.seq = 0;
310 pkt.whdr.type = RXRPC_PACKET_TYPE_ABORT;
311 pkt.whdr.flags = conn->out_clientflag;
312 pkt.whdr.userStatus = 0;
313 pkt.whdr.securityIndex = call->security_ix;
314 pkt.whdr._rsvd = 0;
315 pkt.whdr.serviceId = htons(call->dest_srx.srx_service);
316 pkt.abort_code = htonl(call->abort_code);
317
318 iov[0].iov_base = &pkt;
319 iov[0].iov_len = sizeof(pkt);
320
321 serial = atomic_inc_return(&conn->serial);
322 pkt.whdr.serial = htonl(serial);
323
324 iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, sizeof(pkt));
325 ret = do_udp_sendmsg(conn->local->socket, &msg, sizeof(pkt));
326 conn->peer->last_tx_at = ktime_get_seconds();
327 if (ret < 0)
328 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
329 rxrpc_tx_point_call_abort);
330 else
331 trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
332 rxrpc_tx_point_call_abort);
333 rxrpc_tx_backoff(call, ret);
334 return ret;
335}
336
337/*
338 * send a packet through the transport endpoint
339 */
340int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
341{
342 enum rxrpc_req_ack_trace why;
343 struct rxrpc_connection *conn = call->conn;
344 struct msghdr msg;
345 struct kvec iov[1];
346 rxrpc_serial_t serial;
347 size_t len;
348 int ret, rtt_slot = -1;
349
350 _enter("%x,{%d}", txb->seq, txb->len);
351
352 /* Each transmission of a Tx packet needs a new serial number */
353 serial = atomic_inc_return(&conn->serial);
354 txb->wire.serial = htonl(serial);
355
356 if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
357 txb->seq == 1)
358 txb->wire.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
359
360 iov[0].iov_base = &txb->wire;
361 iov[0].iov_len = sizeof(txb->wire) + txb->len;
362 len = iov[0].iov_len;
363 iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
364
365 msg.msg_name = &call->peer->srx.transport;
366 msg.msg_namelen = call->peer->srx.transport_len;
367 msg.msg_control = NULL;
368 msg.msg_controllen = 0;
369 msg.msg_flags = 0;
370
371 /* If our RTT cache needs working on, request an ACK. Also request
372 * ACKs if a DATA packet appears to have been lost.
373 *
374 * However, we mustn't request an ACK on the last reply packet of a
375 * service call, lest OpenAFS incorrectly send us an ACK with some
376 * soft-ACKs in it and then never follow up with a proper hard ACK.
377 */
378 if (txb->wire.flags & RXRPC_REQUEST_ACK)
379 why = rxrpc_reqack_already_on;
380 else if (test_bit(RXRPC_TXBUF_LAST, &txb->flags) && rxrpc_sending_to_client(txb))
381 why = rxrpc_reqack_no_srv_last;
382 else if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
383 why = rxrpc_reqack_ack_lost;
384 else if (test_bit(RXRPC_TXBUF_RESENT, &txb->flags))
385 why = rxrpc_reqack_retrans;
386 else if (call->cong_mode == RXRPC_CALL_SLOW_START && call->cong_cwnd <= 2)
387 why = rxrpc_reqack_slow_start;
388 else if (call->tx_winsize <= 2)
389 why = rxrpc_reqack_small_txwin;
390 else if (call->peer->rtt_count < 3 && txb->seq & 1)
391 why = rxrpc_reqack_more_rtt;
392 else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime_get_real()))
393 why = rxrpc_reqack_old_rtt;
394 else
395 goto dont_set_request_ack;
396
397 rxrpc_inc_stat(call->rxnet, stat_why_req_ack[why]);
398 trace_rxrpc_req_ack(call->debug_id, txb->seq, why);
399 if (why != rxrpc_reqack_no_srv_last)
400 txb->wire.flags |= RXRPC_REQUEST_ACK;
401dont_set_request_ack:
402
403 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
404 static int lose;
405 if ((lose++ & 7) == 7) {
406 ret = 0;
407 trace_rxrpc_tx_data(call, txb->seq, serial,
408 txb->wire.flags,
409 test_bit(RXRPC_TXBUF_RESENT, &txb->flags),
410 true);
411 goto done;
412 }
413 }
414
415 trace_rxrpc_tx_data(call, txb->seq, serial, txb->wire.flags,
416 test_bit(RXRPC_TXBUF_RESENT, &txb->flags), false);
417
418 /* Track what we've attempted to transmit at least once so that the
419 * retransmission algorithm doesn't try to resend what we haven't sent
420 * yet. However, this can race as we can receive an ACK before we get
421 * to this point. But, OTOH, if we won't get an ACK mentioning this
422 * packet unless the far side received it (though it could have
423 * discarded it anyway and NAK'd it).
424 */
425 cmpxchg(&call->tx_transmitted, txb->seq - 1, txb->seq);
426
427 /* send the packet with the don't fragment bit set if we currently
428 * think it's small enough */
429 if (txb->len >= call->peer->maxdata)
430 goto send_fragmentable;
431
432 down_read(&conn->local->defrag_sem);
433
434 txb->last_sent = ktime_get_real();
435 if (txb->wire.flags & RXRPC_REQUEST_ACK)
436 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
437
438 /* send the packet by UDP
439 * - returns -EMSGSIZE if UDP would have to fragment the packet
440 * to go out of the interface
441 * - in which case, we'll have processed the ICMP error
442 * message and update the peer record
443 */
444 rxrpc_inc_stat(call->rxnet, stat_tx_data_send);
445 ret = do_udp_sendmsg(conn->local->socket, &msg, len);
446 conn->peer->last_tx_at = ktime_get_seconds();
447
448 up_read(&conn->local->defrag_sem);
449 if (ret < 0) {
450 rxrpc_inc_stat(call->rxnet, stat_tx_data_send_fail);
451 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
452 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
453 rxrpc_tx_point_call_data_nofrag);
454 } else {
455 trace_rxrpc_tx_packet(call->debug_id, &txb->wire,
456 rxrpc_tx_point_call_data_nofrag);
457 }
458
459 rxrpc_tx_backoff(call, ret);
460 if (ret == -EMSGSIZE)
461 goto send_fragmentable;
462
463done:
464 if (ret >= 0) {
465 call->tx_last_sent = txb->last_sent;
466 if (txb->wire.flags & RXRPC_REQUEST_ACK) {
467 call->peer->rtt_last_req = txb->last_sent;
468 if (call->peer->rtt_count > 1) {
469 unsigned long nowj = jiffies, ack_lost_at;
470
471 ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
472 ack_lost_at += nowj;
473 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
474 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
475 rxrpc_timer_set_for_lost_ack);
476 }
477 }
478
479 if (txb->seq == 1 &&
480 !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
481 &call->flags)) {
482 unsigned long nowj = jiffies, expect_rx_by;
483
484 expect_rx_by = nowj + call->next_rx_timo;
485 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
486 rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
487 rxrpc_timer_set_for_normal);
488 }
489
490 rxrpc_set_keepalive(call);
491 } else {
492 /* Cancel the call if the initial transmission fails,
493 * particularly if that's due to network routing issues that
494 * aren't going away anytime soon. The layer above can arrange
495 * the retransmission.
496 */
497 if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
498 rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
499 RX_USER_ABORT, ret);
500 }
501
502 _leave(" = %d [%u]", ret, call->peer->maxdata);
503 return ret;
504
505send_fragmentable:
506 /* attempt to send this message with fragmentation enabled */
507 _debug("send fragment");
508
509 down_write(&conn->local->defrag_sem);
510
511 txb->last_sent = ktime_get_real();
512 if (txb->wire.flags & RXRPC_REQUEST_ACK)
513 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
514
515 switch (conn->local->srx.transport.family) {
516 case AF_INET6:
517 case AF_INET:
518 ip_sock_set_mtu_discover(conn->local->socket->sk,
519 IP_PMTUDISC_DONT);
520 rxrpc_inc_stat(call->rxnet, stat_tx_data_send_frag);
521 ret = do_udp_sendmsg(conn->local->socket, &msg, len);
522 conn->peer->last_tx_at = ktime_get_seconds();
523
524 ip_sock_set_mtu_discover(conn->local->socket->sk,
525 IP_PMTUDISC_DO);
526 break;
527
528 default:
529 BUG();
530 }
531
532 if (ret < 0) {
533 rxrpc_inc_stat(call->rxnet, stat_tx_data_send_fail);
534 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
535 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
536 rxrpc_tx_point_call_data_frag);
537 } else {
538 trace_rxrpc_tx_packet(call->debug_id, &txb->wire,
539 rxrpc_tx_point_call_data_frag);
540 }
541 rxrpc_tx_backoff(call, ret);
542
543 up_write(&conn->local->defrag_sem);
544 goto done;
545}
546
547/*
548 * Transmit a connection-level abort.
549 */
550void rxrpc_send_conn_abort(struct rxrpc_connection *conn)
551{
552 struct rxrpc_wire_header whdr;
553 struct msghdr msg;
554 struct kvec iov[2];
555 __be32 word;
556 size_t len;
557 u32 serial;
558 int ret;
559
560 msg.msg_name = &conn->peer->srx.transport;
561 msg.msg_namelen = conn->peer->srx.transport_len;
562 msg.msg_control = NULL;
563 msg.msg_controllen = 0;
564 msg.msg_flags = 0;
565
566 whdr.epoch = htonl(conn->proto.epoch);
567 whdr.cid = htonl(conn->proto.cid);
568 whdr.callNumber = 0;
569 whdr.seq = 0;
570 whdr.type = RXRPC_PACKET_TYPE_ABORT;
571 whdr.flags = conn->out_clientflag;
572 whdr.userStatus = 0;
573 whdr.securityIndex = conn->security_ix;
574 whdr._rsvd = 0;
575 whdr.serviceId = htons(conn->service_id);
576
577 word = htonl(conn->abort_code);
578
579 iov[0].iov_base = &whdr;
580 iov[0].iov_len = sizeof(whdr);
581 iov[1].iov_base = &word;
582 iov[1].iov_len = sizeof(word);
583
584 len = iov[0].iov_len + iov[1].iov_len;
585
586 serial = atomic_inc_return(&conn->serial);
587 whdr.serial = htonl(serial);
588
589 iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
590 ret = do_udp_sendmsg(conn->local->socket, &msg, len);
591 if (ret < 0) {
592 trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
593 rxrpc_tx_point_conn_abort);
594 _debug("sendmsg failed: %d", ret);
595 return;
596 }
597
598 trace_rxrpc_tx_packet(conn->debug_id, &whdr, rxrpc_tx_point_conn_abort);
599
600 conn->peer->last_tx_at = ktime_get_seconds();
601}
602
603/*
604 * Reject a packet through the local endpoint.
605 */
606void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
607{
608 struct rxrpc_wire_header whdr;
609 struct sockaddr_rxrpc srx;
610 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
611 struct msghdr msg;
612 struct kvec iov[2];
613 size_t size;
614 __be32 code;
615 int ret, ioc;
616
617 rxrpc_see_skb(skb, rxrpc_skb_see_reject);
618
619 iov[0].iov_base = &whdr;
620 iov[0].iov_len = sizeof(whdr);
621 iov[1].iov_base = &code;
622 iov[1].iov_len = sizeof(code);
623
624 msg.msg_name = &srx.transport;
625 msg.msg_control = NULL;
626 msg.msg_controllen = 0;
627 msg.msg_flags = 0;
628
629 memset(&whdr, 0, sizeof(whdr));
630
631 switch (skb->mark) {
632 case RXRPC_SKB_MARK_REJECT_BUSY:
633 whdr.type = RXRPC_PACKET_TYPE_BUSY;
634 size = sizeof(whdr);
635 ioc = 1;
636 break;
637 case RXRPC_SKB_MARK_REJECT_ABORT:
638 whdr.type = RXRPC_PACKET_TYPE_ABORT;
639 code = htonl(skb->priority);
640 size = sizeof(whdr) + sizeof(code);
641 ioc = 2;
642 break;
643 default:
644 return;
645 }
646
647 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
648 msg.msg_namelen = srx.transport_len;
649
650 whdr.epoch = htonl(sp->hdr.epoch);
651 whdr.cid = htonl(sp->hdr.cid);
652 whdr.callNumber = htonl(sp->hdr.callNumber);
653 whdr.serviceId = htons(sp->hdr.serviceId);
654 whdr.flags = sp->hdr.flags;
655 whdr.flags ^= RXRPC_CLIENT_INITIATED;
656 whdr.flags &= RXRPC_CLIENT_INITIATED;
657
658 iov_iter_kvec(&msg.msg_iter, WRITE, iov, ioc, size);
659 ret = do_udp_sendmsg(local->socket, &msg, size);
660 if (ret < 0)
661 trace_rxrpc_tx_fail(local->debug_id, 0, ret,
662 rxrpc_tx_point_reject);
663 else
664 trace_rxrpc_tx_packet(local->debug_id, &whdr,
665 rxrpc_tx_point_reject);
666 }
667}
668
669/*
670 * Send a VERSION reply to a peer as a keepalive.
671 */
672void rxrpc_send_keepalive(struct rxrpc_peer *peer)
673{
674 struct rxrpc_wire_header whdr;
675 struct msghdr msg;
676 struct kvec iov[2];
677 size_t len;
678 int ret;
679
680 _enter("");
681
682 msg.msg_name = &peer->srx.transport;
683 msg.msg_namelen = peer->srx.transport_len;
684 msg.msg_control = NULL;
685 msg.msg_controllen = 0;
686 msg.msg_flags = 0;
687
688 whdr.epoch = htonl(peer->local->rxnet->epoch);
689 whdr.cid = 0;
690 whdr.callNumber = 0;
691 whdr.seq = 0;
692 whdr.serial = 0;
693 whdr.type = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
694 whdr.flags = RXRPC_LAST_PACKET;
695 whdr.userStatus = 0;
696 whdr.securityIndex = 0;
697 whdr._rsvd = 0;
698 whdr.serviceId = 0;
699
700 iov[0].iov_base = &whdr;
701 iov[0].iov_len = sizeof(whdr);
702 iov[1].iov_base = (char *)rxrpc_keepalive_string;
703 iov[1].iov_len = sizeof(rxrpc_keepalive_string);
704
705 len = iov[0].iov_len + iov[1].iov_len;
706
707 iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
708 ret = do_udp_sendmsg(peer->local->socket, &msg, len);
709 if (ret < 0)
710 trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
711 rxrpc_tx_point_version_keepalive);
712 else
713 trace_rxrpc_tx_packet(peer->debug_id, &whdr,
714 rxrpc_tx_point_version_keepalive);
715
716 peer->last_tx_at = ktime_get_seconds();
717 _leave("");
718}
719
720/*
721 * Schedule an instant Tx resend.
722 */
723static inline void rxrpc_instant_resend(struct rxrpc_call *call,
724 struct rxrpc_txbuf *txb)
725{
726 if (!__rxrpc_call_is_complete(call))
727 kdebug("resend");
728}
729
730/*
731 * Transmit one packet.
732 */
733void rxrpc_transmit_one(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
734{
735 int ret;
736
737 ret = rxrpc_send_data_packet(call, txb);
738 if (ret < 0) {
739 switch (ret) {
740 case -ENETUNREACH:
741 case -EHOSTUNREACH:
742 case -ECONNREFUSED:
743 rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
744 0, ret);
745 break;
746 default:
747 _debug("need instant resend %d", ret);
748 rxrpc_instant_resend(call, txb);
749 }
750 } else {
751 unsigned long now = jiffies;
752 unsigned long resend_at = now + call->peer->rto_j;
753
754 WRITE_ONCE(call->resend_at, resend_at);
755 rxrpc_reduce_call_timer(call, resend_at, now,
756 rxrpc_timer_set_for_send);
757 }
758}