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[deliverable/linux.git] / net / rxrpc / sendmsg.c
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
22 enum 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 */
33 static 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 < call->tx_winsize)
49 break;
50 if (call->state >= RXRPC_CALL_COMPLETE) {
51 ret = -call->error;
52 break;
53 }
54 if (signal_pending(current)) {
55 ret = sock_intr_errno(*timeo);
56 break;
57 }
58
59 release_sock(&rx->sk);
60 *timeo = schedule_timeout(*timeo);
61 lock_sock(&rx->sk);
62 }
63
64 remove_wait_queue(&call->waitq, &myself);
65 set_current_state(TASK_RUNNING);
66 _leave(" = %d", ret);
67 return ret;
68 }
69
70 /*
71 * Schedule an instant Tx resend.
72 */
73 static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
74 {
75 spin_lock_bh(&call->lock);
76
77 if (call->state < RXRPC_CALL_COMPLETE) {
78 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
79 if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
80 rxrpc_queue_call(call);
81 }
82
83 spin_unlock_bh(&call->lock);
84 }
85
86 /*
87 * Queue a DATA packet for transmission, set the resend timeout and send the
88 * packet immediately
89 */
90 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
91 bool last)
92 {
93 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
94 rxrpc_seq_t seq = sp->hdr.seq;
95 int ret, ix;
96
97 _net("queue skb %p [%d]", skb, seq);
98
99 ASSERTCMP(seq, ==, call->tx_top + 1);
100
101 ix = seq & RXRPC_RXTX_BUFF_MASK;
102 rxrpc_get_skb(skb);
103 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_UNACK;
104 smp_wmb();
105 call->rxtx_buffer[ix] = skb;
106 call->tx_top = seq;
107 if (last)
108 set_bit(RXRPC_CALL_TX_LAST, &call->flags);
109
110 if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
111 _debug("________awaiting reply/ACK__________");
112 write_lock_bh(&call->state_lock);
113 switch (call->state) {
114 case RXRPC_CALL_CLIENT_SEND_REQUEST:
115 call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
116 break;
117 case RXRPC_CALL_SERVER_ACK_REQUEST:
118 call->state = RXRPC_CALL_SERVER_SEND_REPLY;
119 if (!last)
120 break;
121 case RXRPC_CALL_SERVER_SEND_REPLY:
122 call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
123 break;
124 default:
125 break;
126 }
127 write_unlock_bh(&call->state_lock);
128 }
129
130 _proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
131
132 if (seq == 1 && rxrpc_is_client_call(call))
133 rxrpc_expose_client_call(call);
134
135 sp->resend_at = jiffies + rxrpc_resend_timeout;
136 ret = rxrpc_send_data_packet(call->conn, skb);
137 if (ret < 0) {
138 _debug("need instant resend %d", ret);
139 rxrpc_instant_resend(call, ix);
140 }
141
142 rxrpc_free_skb(skb);
143 _leave("");
144 }
145
146 /*
147 * Convert a host-endian header into a network-endian header.
148 */
149 static void rxrpc_insert_header(struct sk_buff *skb)
150 {
151 struct rxrpc_wire_header whdr;
152 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
153
154 whdr.epoch = htonl(sp->hdr.epoch);
155 whdr.cid = htonl(sp->hdr.cid);
156 whdr.callNumber = htonl(sp->hdr.callNumber);
157 whdr.seq = htonl(sp->hdr.seq);
158 whdr.serial = htonl(sp->hdr.serial);
159 whdr.type = sp->hdr.type;
160 whdr.flags = sp->hdr.flags;
161 whdr.userStatus = sp->hdr.userStatus;
162 whdr.securityIndex = sp->hdr.securityIndex;
163 whdr._rsvd = htons(sp->hdr._rsvd);
164 whdr.serviceId = htons(sp->hdr.serviceId);
165
166 memcpy(skb->head, &whdr, sizeof(whdr));
167 }
168
169 /*
170 * send data through a socket
171 * - must be called in process context
172 * - caller holds the socket locked
173 */
174 static int rxrpc_send_data(struct rxrpc_sock *rx,
175 struct rxrpc_call *call,
176 struct msghdr *msg, size_t len)
177 {
178 struct rxrpc_skb_priv *sp;
179 struct sk_buff *skb;
180 struct sock *sk = &rx->sk;
181 long timeo;
182 bool more;
183 int ret, copied;
184
185 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
186
187 /* this should be in poll */
188 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
189
190 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
191 return -EPIPE;
192
193 more = msg->msg_flags & MSG_MORE;
194
195 skb = call->tx_pending;
196 call->tx_pending = NULL;
197 rxrpc_see_skb(skb);
198
199 copied = 0;
200 do {
201 if (!skb) {
202 size_t size, chunk, max, space;
203
204 _debug("alloc");
205
206 if (call->tx_top - call->tx_hard_ack >=
207 call->tx_winsize) {
208 ret = -EAGAIN;
209 if (msg->msg_flags & MSG_DONTWAIT)
210 goto maybe_error;
211 ret = rxrpc_wait_for_tx_window(rx, call,
212 &timeo);
213 if (ret < 0)
214 goto maybe_error;
215 }
216
217 max = call->conn->params.peer->maxdata;
218 max -= call->conn->security_size;
219 max &= ~(call->conn->size_align - 1UL);
220
221 chunk = max;
222 if (chunk > msg_data_left(msg) && !more)
223 chunk = msg_data_left(msg);
224
225 space = chunk + call->conn->size_align;
226 space &= ~(call->conn->size_align - 1UL);
227
228 size = space + call->conn->header_size;
229
230 _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
231
232 /* create a buffer that we can retain until it's ACK'd */
233 skb = sock_alloc_send_skb(
234 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
235 if (!skb)
236 goto maybe_error;
237
238 rxrpc_new_skb(skb);
239
240 _debug("ALLOC SEND %p", skb);
241
242 ASSERTCMP(skb->mark, ==, 0);
243
244 _debug("HS: %u", call->conn->header_size);
245 skb_reserve(skb, call->conn->header_size);
246 skb->len += call->conn->header_size;
247
248 sp = rxrpc_skb(skb);
249 sp->remain = chunk;
250 if (sp->remain > skb_tailroom(skb))
251 sp->remain = skb_tailroom(skb);
252
253 _net("skb: hr %d, tr %d, hl %d, rm %d",
254 skb_headroom(skb),
255 skb_tailroom(skb),
256 skb_headlen(skb),
257 sp->remain);
258
259 skb->ip_summed = CHECKSUM_UNNECESSARY;
260 }
261
262 _debug("append");
263 sp = rxrpc_skb(skb);
264
265 /* append next segment of data to the current buffer */
266 if (msg_data_left(msg) > 0) {
267 int copy = skb_tailroom(skb);
268 ASSERTCMP(copy, >, 0);
269 if (copy > msg_data_left(msg))
270 copy = msg_data_left(msg);
271 if (copy > sp->remain)
272 copy = sp->remain;
273
274 _debug("add");
275 ret = skb_add_data(skb, &msg->msg_iter, copy);
276 _debug("added");
277 if (ret < 0)
278 goto efault;
279 sp->remain -= copy;
280 skb->mark += copy;
281 copied += copy;
282 }
283
284 /* check for the far side aborting the call or a network error
285 * occurring */
286 if (call->state == RXRPC_CALL_COMPLETE)
287 goto call_terminated;
288
289 /* add the packet to the send queue if it's now full */
290 if (sp->remain <= 0 ||
291 (msg_data_left(msg) == 0 && !more)) {
292 struct rxrpc_connection *conn = call->conn;
293 uint32_t seq;
294 size_t pad;
295
296 /* pad out if we're using security */
297 if (conn->security_ix) {
298 pad = conn->security_size + skb->mark;
299 pad = conn->size_align - pad;
300 pad &= conn->size_align - 1;
301 _debug("pad %zu", pad);
302 if (pad)
303 memset(skb_put(skb, pad), 0, pad);
304 }
305
306 seq = call->tx_top + 1;
307
308 sp->hdr.epoch = conn->proto.epoch;
309 sp->hdr.cid = call->cid;
310 sp->hdr.callNumber = call->call_id;
311 sp->hdr.seq = seq;
312 sp->hdr.serial = atomic_inc_return(&conn->serial);
313 sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
314 sp->hdr.userStatus = 0;
315 sp->hdr.securityIndex = call->security_ix;
316 sp->hdr._rsvd = 0;
317 sp->hdr.serviceId = call->service_id;
318
319 sp->hdr.flags = conn->out_clientflag;
320 if (msg_data_left(msg) == 0 && !more)
321 sp->hdr.flags |= RXRPC_LAST_PACKET;
322 else if (call->tx_top - call->tx_hard_ack <
323 call->tx_winsize)
324 sp->hdr.flags |= RXRPC_MORE_PACKETS;
325 if (more && seq & 1)
326 sp->hdr.flags |= RXRPC_REQUEST_ACK;
327
328 ret = conn->security->secure_packet(
329 call, skb, skb->mark,
330 skb->head + sizeof(struct rxrpc_wire_header));
331 if (ret < 0)
332 goto out;
333
334 rxrpc_insert_header(skb);
335 rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
336 skb = NULL;
337 }
338 } while (msg_data_left(msg) > 0);
339
340 success:
341 ret = copied;
342 out:
343 call->tx_pending = skb;
344 _leave(" = %d", ret);
345 return ret;
346
347 call_terminated:
348 rxrpc_free_skb(skb);
349 _leave(" = %d", -call->error);
350 return -call->error;
351
352 maybe_error:
353 if (copied)
354 goto success;
355 goto out;
356
357 efault:
358 ret = -EFAULT;
359 goto out;
360 }
361
362 /*
363 * extract control messages from the sendmsg() control buffer
364 */
365 static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
366 unsigned long *user_call_ID,
367 enum rxrpc_command *command,
368 u32 *abort_code,
369 bool *_exclusive)
370 {
371 struct cmsghdr *cmsg;
372 bool got_user_ID = false;
373 int len;
374
375 *command = RXRPC_CMD_SEND_DATA;
376
377 if (msg->msg_controllen == 0)
378 return -EINVAL;
379
380 for_each_cmsghdr(cmsg, msg) {
381 if (!CMSG_OK(msg, cmsg))
382 return -EINVAL;
383
384 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
385 _debug("CMSG %d, %d, %d",
386 cmsg->cmsg_level, cmsg->cmsg_type, len);
387
388 if (cmsg->cmsg_level != SOL_RXRPC)
389 continue;
390
391 switch (cmsg->cmsg_type) {
392 case RXRPC_USER_CALL_ID:
393 if (msg->msg_flags & MSG_CMSG_COMPAT) {
394 if (len != sizeof(u32))
395 return -EINVAL;
396 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
397 } else {
398 if (len != sizeof(unsigned long))
399 return -EINVAL;
400 *user_call_ID = *(unsigned long *)
401 CMSG_DATA(cmsg);
402 }
403 _debug("User Call ID %lx", *user_call_ID);
404 got_user_ID = true;
405 break;
406
407 case RXRPC_ABORT:
408 if (*command != RXRPC_CMD_SEND_DATA)
409 return -EINVAL;
410 *command = RXRPC_CMD_SEND_ABORT;
411 if (len != sizeof(*abort_code))
412 return -EINVAL;
413 *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
414 _debug("Abort %x", *abort_code);
415 if (*abort_code == 0)
416 return -EINVAL;
417 break;
418
419 case RXRPC_ACCEPT:
420 if (*command != RXRPC_CMD_SEND_DATA)
421 return -EINVAL;
422 *command = RXRPC_CMD_ACCEPT;
423 if (len != 0)
424 return -EINVAL;
425 break;
426
427 case RXRPC_EXCLUSIVE_CALL:
428 *_exclusive = true;
429 if (len != 0)
430 return -EINVAL;
431 break;
432 default:
433 return -EINVAL;
434 }
435 }
436
437 if (!got_user_ID)
438 return -EINVAL;
439 _leave(" = 0");
440 return 0;
441 }
442
443 /*
444 * Create a new client call for sendmsg().
445 */
446 static struct rxrpc_call *
447 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
448 unsigned long user_call_ID, bool exclusive)
449 {
450 struct rxrpc_conn_parameters cp;
451 struct rxrpc_call *call;
452 struct key *key;
453
454 DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
455
456 _enter("");
457
458 if (!msg->msg_name)
459 return ERR_PTR(-EDESTADDRREQ);
460
461 key = rx->key;
462 if (key && !rx->key->payload.data[0])
463 key = NULL;
464
465 memset(&cp, 0, sizeof(cp));
466 cp.local = rx->local;
467 cp.key = rx->key;
468 cp.security_level = rx->min_sec_level;
469 cp.exclusive = rx->exclusive | exclusive;
470 cp.service_id = srx->srx_service;
471 call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
472
473 _leave(" = %p\n", call);
474 return call;
475 }
476
477 /*
478 * send a message forming part of a client call through an RxRPC socket
479 * - caller holds the socket locked
480 * - the socket may be either a client socket or a server socket
481 */
482 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
483 {
484 enum rxrpc_command cmd;
485 struct rxrpc_call *call;
486 unsigned long user_call_ID = 0;
487 bool exclusive = false;
488 u32 abort_code = 0;
489 int ret;
490
491 _enter("");
492
493 ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
494 &exclusive);
495 if (ret < 0)
496 return ret;
497
498 if (cmd == RXRPC_CMD_ACCEPT) {
499 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
500 return -EINVAL;
501 call = rxrpc_accept_call(rx, user_call_ID, NULL);
502 if (IS_ERR(call))
503 return PTR_ERR(call);
504 rxrpc_put_call(call, rxrpc_call_put);
505 return 0;
506 }
507
508 call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
509 if (!call) {
510 if (cmd != RXRPC_CMD_SEND_DATA)
511 return -EBADSLT;
512 call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
513 exclusive);
514 if (IS_ERR(call))
515 return PTR_ERR(call);
516 }
517
518 _debug("CALL %d USR %lx ST %d on CONN %p",
519 call->debug_id, call->user_call_ID, call->state, call->conn);
520
521 if (call->state >= RXRPC_CALL_COMPLETE) {
522 /* it's too late for this call */
523 ret = -ESHUTDOWN;
524 } else if (cmd == RXRPC_CMD_SEND_ABORT) {
525 ret = 0;
526 if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
527 ret = rxrpc_send_call_packet(call,
528 RXRPC_PACKET_TYPE_ABORT);
529 } else if (cmd != RXRPC_CMD_SEND_DATA) {
530 ret = -EINVAL;
531 } else if (rxrpc_is_client_call(call) &&
532 call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
533 /* request phase complete for this client call */
534 ret = -EPROTO;
535 } else if (rxrpc_is_service_call(call) &&
536 call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
537 call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
538 /* Reply phase not begun or not complete for service call. */
539 ret = -EPROTO;
540 } else {
541 ret = rxrpc_send_data(rx, call, msg, len);
542 }
543
544 rxrpc_put_call(call, rxrpc_call_put);
545 _leave(" = %d", ret);
546 return ret;
547 }
548
549 /**
550 * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
551 * @sock: The socket the call is on
552 * @call: The call to send data through
553 * @msg: The data to send
554 * @len: The amount of data to send
555 *
556 * Allow a kernel service to send data on a call. The call must be in an state
557 * appropriate to sending data. No control data should be supplied in @msg,
558 * nor should an address be supplied. MSG_MORE should be flagged if there's
559 * more data to come, otherwise this data will end the transmission phase.
560 */
561 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
562 struct msghdr *msg, size_t len)
563 {
564 int ret;
565
566 _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
567
568 ASSERTCMP(msg->msg_name, ==, NULL);
569 ASSERTCMP(msg->msg_control, ==, NULL);
570
571 lock_sock(sock->sk);
572
573 _debug("CALL %d USR %lx ST %d on CONN %p",
574 call->debug_id, call->user_call_ID, call->state, call->conn);
575
576 if (call->state >= RXRPC_CALL_COMPLETE) {
577 ret = -ESHUTDOWN; /* it's too late for this call */
578 } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
579 call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
580 call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
581 ret = -EPROTO; /* request phase complete for this client call */
582 } else {
583 ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
584 }
585
586 release_sock(sock->sk);
587 _leave(" = %d", ret);
588 return ret;
589 }
590 EXPORT_SYMBOL(rxrpc_kernel_send_data);
591
592 /**
593 * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
594 * @sock: The socket the call is on
595 * @call: The call to be aborted
596 * @abort_code: The abort code to stick into the ABORT packet
597 * @error: Local error value
598 * @why: 3-char string indicating why.
599 *
600 * Allow a kernel service to abort a call, if it's still in an abortable state.
601 */
602 void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
603 u32 abort_code, int error, const char *why)
604 {
605 _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
606
607 lock_sock(sock->sk);
608
609 if (rxrpc_abort_call(why, call, 0, abort_code, error))
610 rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
611
612 release_sock(sock->sk);
613 _leave("");
614 }
615
616 EXPORT_SYMBOL(rxrpc_kernel_abort_call);
Linux kernel - Deliverables
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