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1/* AF_RXRPC sendmsg() implementation.
2 *
3 * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/net.h>
15#include <linux/gfp.h>
16#include <linux/skbuff.h>
17#include <linux/export.h>
18#include <net/sock.h>
19#include <net/af_rxrpc.h>
20#include "ar-internal.h"
21
22enum rxrpc_command {
23 RXRPC_CMD_SEND_DATA, /* send data message */
24 RXRPC_CMD_SEND_ABORT, /* request abort generation */
25 RXRPC_CMD_ACCEPT, /* [server] accept incoming call */
26 RXRPC_CMD_REJECT_BUSY, /* [server] reject a call as busy */
27};
28
29/*
30 * wait for space to appear in the transmit/ACK window
31 * - caller holds the socket locked
32 */
33static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
34 struct rxrpc_call *call,
35 long *timeo)
36{
37 DECLARE_WAITQUEUE(myself, current);
38 int ret;
39
40 _enter(",{%u,%u,%u}",
41 call->tx_hard_ack, call->tx_top, call->tx_winsize);
42
43 add_wait_queue(&call->waitq, &myself);
44
45 for (;;) {
46 set_current_state(TASK_INTERRUPTIBLE);
47 ret = 0;
48 if (call->tx_top - call->tx_hard_ack <
49 min_t(unsigned int, call->tx_winsize,
50 call->cong_cwnd + call->cong_extra))
51 break;
52 if (call->state >= RXRPC_CALL_COMPLETE) {
53 ret = -call->error;
54 break;
55 }
56 if (signal_pending(current)) {
57 ret = sock_intr_errno(*timeo);
58 break;
59 }
60
61 trace_rxrpc_transmit(call, rxrpc_transmit_wait);
62 release_sock(&rx->sk);
63 *timeo = schedule_timeout(*timeo);
64 lock_sock(&rx->sk);
65 }
66
67 remove_wait_queue(&call->waitq, &myself);
68 set_current_state(TASK_RUNNING);
69 _leave(" = %d", ret);
70 return ret;
71}
72
73/*
74 * Schedule an instant Tx resend.
75 */
76static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
77{
78 spin_lock_bh(&call->lock);
79
80 if (call->state < RXRPC_CALL_COMPLETE) {
81 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
82 if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
83 rxrpc_queue_call(call);
84 }
85
86 spin_unlock_bh(&call->lock);
87}
88
89/*
90 * Queue a DATA packet for transmission, set the resend timeout and send the
91 * packet immediately
92 */
93static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
94 bool last)
95{
96 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
97 rxrpc_seq_t seq = sp->hdr.seq;
98 int ret, ix;
99 u8 annotation = RXRPC_TX_ANNO_UNACK;
100
101 _net("queue skb %p [%d]", skb, seq);
102
103 ASSERTCMP(seq, ==, call->tx_top + 1);
104
105 if (last)
106 annotation |= RXRPC_TX_ANNO_LAST;
107
108 /* We have to set the timestamp before queueing as the retransmit
109 * algorithm can see the packet as soon as we queue it.
110 */
111 skb->tstamp = ktime_get_real();
112
113 ix = seq & RXRPC_RXTX_BUFF_MASK;
114 rxrpc_get_skb(skb, rxrpc_skb_tx_got);
115 call->rxtx_annotations[ix] = annotation;
116 smp_wmb();
117 call->rxtx_buffer[ix] = skb;
118 call->tx_top = seq;
119 if (last)
120 trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
121 else
122 trace_rxrpc_transmit(call, rxrpc_transmit_queue);
123
124 if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
125 _debug("________awaiting reply/ACK__________");
126 write_lock_bh(&call->state_lock);
127 switch (call->state) {
128 case RXRPC_CALL_CLIENT_SEND_REQUEST:
129 call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
130 break;
131 case RXRPC_CALL_SERVER_ACK_REQUEST:
132 call->state = RXRPC_CALL_SERVER_SEND_REPLY;
133 call->ack_at = call->expire_at;
134 if (call->ackr_reason == RXRPC_ACK_DELAY)
135 call->ackr_reason = 0;
136 __rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply,
137 ktime_get_real());
138 if (!last)
139 break;
140 case RXRPC_CALL_SERVER_SEND_REPLY:
141 call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
142 break;
143 default:
144 break;
145 }
146 write_unlock_bh(&call->state_lock);
147 }
148
149 if (seq == 1 && rxrpc_is_client_call(call))
150 rxrpc_expose_client_call(call);
151
152 ret = rxrpc_send_data_packet(call, skb, false);
153 if (ret < 0) {
154 _debug("need instant resend %d", ret);
155 rxrpc_instant_resend(call, ix);
156 } else {
157 ktime_t now = ktime_get_real(), resend_at;
158
159 resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
160
161 if (ktime_before(resend_at, call->resend_at)) {
162 call->resend_at = resend_at;
163 rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
164 }
165 }
166
167 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
168 _leave("");
169}
170
171/*
172 * send data through a socket
173 * - must be called in process context
174 * - caller holds the socket locked
175 */
176static int rxrpc_send_data(struct rxrpc_sock *rx,
177 struct rxrpc_call *call,
178 struct msghdr *msg, size_t len)
179{
180 struct rxrpc_skb_priv *sp;
181 struct sk_buff *skb;
182 struct sock *sk = &rx->sk;
183 long timeo;
184 bool more;
185 int ret, copied;
186
187 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
188
189 /* this should be in poll */
190 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
191
192 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
193 return -EPIPE;
194
195 more = msg->msg_flags & MSG_MORE;
196
197 skb = call->tx_pending;
198 call->tx_pending = NULL;
199 rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
200
201 copied = 0;
202 do {
203 /* Check to see if there's a ping ACK to reply to. */
204 if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
205 rxrpc_send_ack_packet(call, false);
206
207 if (!skb) {
208 size_t size, chunk, max, space;
209
210 _debug("alloc");
211
212 if (call->tx_top - call->tx_hard_ack >=
213 min_t(unsigned int, call->tx_winsize,
214 call->cong_cwnd + call->cong_extra)) {
215 ret = -EAGAIN;
216 if (msg->msg_flags & MSG_DONTWAIT)
217 goto maybe_error;
218 ret = rxrpc_wait_for_tx_window(rx, call,
219 &timeo);
220 if (ret < 0)
221 goto maybe_error;
222 }
223
224 max = RXRPC_JUMBO_DATALEN;
225 max -= call->conn->security_size;
226 max &= ~(call->conn->size_align - 1UL);
227
228 chunk = max;
229 if (chunk > msg_data_left(msg) && !more)
230 chunk = msg_data_left(msg);
231
232 space = chunk + call->conn->size_align;
233 space &= ~(call->conn->size_align - 1UL);
234
235 size = space + call->conn->security_size;
236
237 _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
238
239 /* create a buffer that we can retain until it's ACK'd */
240 skb = sock_alloc_send_skb(
241 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
242 if (!skb)
243 goto maybe_error;
244
245 rxrpc_new_skb(skb, rxrpc_skb_tx_new);
246
247 _debug("ALLOC SEND %p", skb);
248
249 ASSERTCMP(skb->mark, ==, 0);
250
251 _debug("HS: %u", call->conn->security_size);
252 skb_reserve(skb, call->conn->security_size);
253 skb->len += call->conn->security_size;
254
255 sp = rxrpc_skb(skb);
256 sp->remain = chunk;
257 if (sp->remain > skb_tailroom(skb))
258 sp->remain = skb_tailroom(skb);
259
260 _net("skb: hr %d, tr %d, hl %d, rm %d",
261 skb_headroom(skb),
262 skb_tailroom(skb),
263 skb_headlen(skb),
264 sp->remain);
265
266 skb->ip_summed = CHECKSUM_UNNECESSARY;
267 }
268
269 _debug("append");
270 sp = rxrpc_skb(skb);
271
272 /* append next segment of data to the current buffer */
273 if (msg_data_left(msg) > 0) {
274 int copy = skb_tailroom(skb);
275 ASSERTCMP(copy, >, 0);
276 if (copy > msg_data_left(msg))
277 copy = msg_data_left(msg);
278 if (copy > sp->remain)
279 copy = sp->remain;
280
281 _debug("add");
282 ret = skb_add_data(skb, &msg->msg_iter, copy);
283 _debug("added");
284 if (ret < 0)
285 goto efault;
286 sp->remain -= copy;
287 skb->mark += copy;
288 copied += copy;
289 }
290
291 /* check for the far side aborting the call or a network error
292 * occurring */
293 if (call->state == RXRPC_CALL_COMPLETE)
294 goto call_terminated;
295
296 /* add the packet to the send queue if it's now full */
297 if (sp->remain <= 0 ||
298 (msg_data_left(msg) == 0 && !more)) {
299 struct rxrpc_connection *conn = call->conn;
300 uint32_t seq;
301 size_t pad;
302
303 /* pad out if we're using security */
304 if (conn->security_ix) {
305 pad = conn->security_size + skb->mark;
306 pad = conn->size_align - pad;
307 pad &= conn->size_align - 1;
308 _debug("pad %zu", pad);
309 if (pad)
310 memset(skb_put(skb, pad), 0, pad);
311 }
312
313 seq = call->tx_top + 1;
314
315 sp->hdr.seq = seq;
316 sp->hdr._rsvd = 0;
317 sp->hdr.flags = conn->out_clientflag;
318
319 if (msg_data_left(msg) == 0 && !more)
320 sp->hdr.flags |= RXRPC_LAST_PACKET;
321 else if (call->tx_top - call->tx_hard_ack <
322 call->tx_winsize)
323 sp->hdr.flags |= RXRPC_MORE_PACKETS;
324
325 ret = conn->security->secure_packet(
326 call, skb, skb->mark, skb->head);
327 if (ret < 0)
328 goto out;
329
330 rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
331 skb = NULL;
332 }
333 } while (msg_data_left(msg) > 0);
334
335success:
336 ret = copied;
337out:
338 call->tx_pending = skb;
339 _leave(" = %d", ret);
340 return ret;
341
342call_terminated:
343 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
344 _leave(" = %d", -call->error);
345 return -call->error;
346
347maybe_error:
348 if (copied)
349 goto success;
350 goto out;
351
352efault:
353 ret = -EFAULT;
354 goto out;
355}
356
357/*
358 * extract control messages from the sendmsg() control buffer
359 */
360static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
361 unsigned long *user_call_ID,
362 enum rxrpc_command *command,
363 u32 *abort_code,
364 bool *_exclusive)
365{
366 struct cmsghdr *cmsg;
367 bool got_user_ID = false;
368 int len;
369
370 *command = RXRPC_CMD_SEND_DATA;
371
372 if (msg->msg_controllen == 0)
373 return -EINVAL;
374
375 for_each_cmsghdr(cmsg, msg) {
376 if (!CMSG_OK(msg, cmsg))
377 return -EINVAL;
378
379 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
380 _debug("CMSG %d, %d, %d",
381 cmsg->cmsg_level, cmsg->cmsg_type, len);
382
383 if (cmsg->cmsg_level != SOL_RXRPC)
384 continue;
385
386 switch (cmsg->cmsg_type) {
387 case RXRPC_USER_CALL_ID:
388 if (msg->msg_flags & MSG_CMSG_COMPAT) {
389 if (len != sizeof(u32))
390 return -EINVAL;
391 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
392 } else {
393 if (len != sizeof(unsigned long))
394 return -EINVAL;
395 *user_call_ID = *(unsigned long *)
396 CMSG_DATA(cmsg);
397 }
398 _debug("User Call ID %lx", *user_call_ID);
399 got_user_ID = true;
400 break;
401
402 case RXRPC_ABORT:
403 if (*command != RXRPC_CMD_SEND_DATA)
404 return -EINVAL;
405 *command = RXRPC_CMD_SEND_ABORT;
406 if (len != sizeof(*abort_code))
407 return -EINVAL;
408 *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
409 _debug("Abort %x", *abort_code);
410 if (*abort_code == 0)
411 return -EINVAL;
412 break;
413
414 case RXRPC_ACCEPT:
415 if (*command != RXRPC_CMD_SEND_DATA)
416 return -EINVAL;
417 *command = RXRPC_CMD_ACCEPT;
418 if (len != 0)
419 return -EINVAL;
420 break;
421
422 case RXRPC_EXCLUSIVE_CALL:
423 *_exclusive = true;
424 if (len != 0)
425 return -EINVAL;
426 break;
427 default:
428 return -EINVAL;
429 }
430 }
431
432 if (!got_user_ID)
433 return -EINVAL;
434 _leave(" = 0");
435 return 0;
436}
437
438/*
439 * Create a new client call for sendmsg().
440 */
441static struct rxrpc_call *
442rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
443 unsigned long user_call_ID, bool exclusive)
444{
445 struct rxrpc_conn_parameters cp;
446 struct rxrpc_call *call;
447 struct key *key;
448
449 DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
450
451 _enter("");
452
453 if (!msg->msg_name)
454 return ERR_PTR(-EDESTADDRREQ);
455
456 key = rx->key;
457 if (key && !rx->key->payload.data[0])
458 key = NULL;
459
460 memset(&cp, 0, sizeof(cp));
461 cp.local = rx->local;
462 cp.key = rx->key;
463 cp.security_level = rx->min_sec_level;
464 cp.exclusive = rx->exclusive | exclusive;
465 cp.service_id = srx->srx_service;
466 call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
467
468 _leave(" = %p\n", call);
469 return call;
470}
471
472/*
473 * send a message forming part of a client call through an RxRPC socket
474 * - caller holds the socket locked
475 * - the socket may be either a client socket or a server socket
476 */
477int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
478{
479 enum rxrpc_command cmd;
480 struct rxrpc_call *call;
481 unsigned long user_call_ID = 0;
482 bool exclusive = false;
483 u32 abort_code = 0;
484 int ret;
485
486 _enter("");
487
488 ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
489 &exclusive);
490 if (ret < 0)
491 return ret;
492
493 if (cmd == RXRPC_CMD_ACCEPT) {
494 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
495 return -EINVAL;
496 call = rxrpc_accept_call(rx, user_call_ID, NULL);
497 if (IS_ERR(call))
498 return PTR_ERR(call);
499 rxrpc_put_call(call, rxrpc_call_put);
500 return 0;
501 }
502
503 call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
504 if (!call) {
505 if (cmd != RXRPC_CMD_SEND_DATA)
506 return -EBADSLT;
507 call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
508 exclusive);
509 if (IS_ERR(call))
510 return PTR_ERR(call);
511 }
512
513 _debug("CALL %d USR %lx ST %d on CONN %p",
514 call->debug_id, call->user_call_ID, call->state, call->conn);
515
516 if (call->state >= RXRPC_CALL_COMPLETE) {
517 /* it's too late for this call */
518 ret = -ESHUTDOWN;
519 } else if (cmd == RXRPC_CMD_SEND_ABORT) {
520 ret = 0;
521 if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
522 ret = rxrpc_send_abort_packet(call);
523 } else if (cmd != RXRPC_CMD_SEND_DATA) {
524 ret = -EINVAL;
525 } else if (rxrpc_is_client_call(call) &&
526 call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
527 /* request phase complete for this client call */
528 ret = -EPROTO;
529 } else if (rxrpc_is_service_call(call) &&
530 call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
531 call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
532 /* Reply phase not begun or not complete for service call. */
533 ret = -EPROTO;
534 } else {
535 ret = rxrpc_send_data(rx, call, msg, len);
536 }
537
538 rxrpc_put_call(call, rxrpc_call_put);
539 _leave(" = %d", ret);
540 return ret;
541}
542
543/**
544 * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
545 * @sock: The socket the call is on
546 * @call: The call to send data through
547 * @msg: The data to send
548 * @len: The amount of data to send
549 *
550 * Allow a kernel service to send data on a call. The call must be in an state
551 * appropriate to sending data. No control data should be supplied in @msg,
552 * nor should an address be supplied. MSG_MORE should be flagged if there's
553 * more data to come, otherwise this data will end the transmission phase.
554 */
555int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
556 struct msghdr *msg, size_t len)
557{
558 int ret;
559
560 _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
561
562 ASSERTCMP(msg->msg_name, ==, NULL);
563 ASSERTCMP(msg->msg_control, ==, NULL);
564
565 lock_sock(sock->sk);
566
567 _debug("CALL %d USR %lx ST %d on CONN %p",
568 call->debug_id, call->user_call_ID, call->state, call->conn);
569
570 if (call->state >= RXRPC_CALL_COMPLETE) {
571 ret = -ESHUTDOWN; /* it's too late for this call */
572 } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
573 call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
574 call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
575 ret = -EPROTO; /* request phase complete for this client call */
576 } else {
577 ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
578 }
579
580 release_sock(sock->sk);
581 _leave(" = %d", ret);
582 return ret;
583}
584EXPORT_SYMBOL(rxrpc_kernel_send_data);
585
586/**
587 * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
588 * @sock: The socket the call is on
589 * @call: The call to be aborted
590 * @abort_code: The abort code to stick into the ABORT packet
591 * @error: Local error value
592 * @why: 3-char string indicating why.
593 *
594 * Allow a kernel service to abort a call, if it's still in an abortable state.
595 */
596void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
597 u32 abort_code, int error, const char *why)
598{
599 _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
600
601 lock_sock(sock->sk);
602
603 if (rxrpc_abort_call(why, call, 0, abort_code, error))
604 rxrpc_send_abort_packet(call);
605
606 release_sock(sock->sk);
607 _leave("");
608}
609
610EXPORT_SYMBOL(rxrpc_kernel_abort_call);