blob: 8510a98b87e1e224b5ba524f2fe75a21d9b41370 [file] [log] [blame]
David Howells17926a72007-04-26 15:48:28 -07001/* RxRPC recvmsg() implementation
2 *
3 * Copyright (C) 2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
Joe Perches9b6d5392016-06-02 12:08:52 -070012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
David Howells17926a72007-04-26 15:48:28 -070014#include <linux/net.h>
15#include <linux/skbuff.h>
Paul Gortmakerbc3b2d72011-07-15 11:47:34 -040016#include <linux/export.h>
Ingo Molnar174cd4b2017-02-02 19:15:33 +010017#include <linux/sched/signal.h>
18
David Howells17926a72007-04-26 15:48:28 -070019#include <net/sock.h>
20#include <net/af_rxrpc.h>
21#include "ar-internal.h"
22
23/*
David Howells248f2192016-09-08 11:10:12 +010024 * Post a call for attention by the socket or kernel service. Further
25 * notifications are suppressed by putting recvmsg_link on a dummy queue.
26 */
27void rxrpc_notify_socket(struct rxrpc_call *call)
28{
29 struct rxrpc_sock *rx;
30 struct sock *sk;
31
32 _enter("%d", call->debug_id);
33
34 if (!list_empty(&call->recvmsg_link))
35 return;
36
37 rcu_read_lock();
38
39 rx = rcu_dereference(call->socket);
40 sk = &rx->sk;
41 if (rx && sk->sk_state < RXRPC_CLOSE) {
42 if (call->notify_rx) {
David Howells20acbd92017-11-02 15:06:08 +000043 spin_lock_bh(&call->notify_lock);
David Howells248f2192016-09-08 11:10:12 +010044 call->notify_rx(sk, call, call->user_call_ID);
David Howells20acbd92017-11-02 15:06:08 +000045 spin_unlock_bh(&call->notify_lock);
David Howells248f2192016-09-08 11:10:12 +010046 } else {
47 write_lock_bh(&rx->recvmsg_lock);
48 if (list_empty(&call->recvmsg_link)) {
49 rxrpc_get_call(call, rxrpc_call_got);
50 list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
51 }
52 write_unlock_bh(&rx->recvmsg_lock);
53
54 if (!sock_flag(sk, SOCK_DEAD)) {
55 _debug("call %ps", sk->sk_data_ready);
56 sk->sk_data_ready(sk);
57 }
58 }
59 }
60
61 rcu_read_unlock();
62 _leave("");
63}
64
65/*
66 * Pass a call terminating message to userspace.
67 */
68static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
69{
70 u32 tmp = 0;
71 int ret;
72
73 switch (call->completion) {
74 case RXRPC_CALL_SUCCEEDED:
75 ret = 0;
76 if (rxrpc_is_service_call(call))
77 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
78 break;
79 case RXRPC_CALL_REMOTELY_ABORTED:
80 tmp = call->abort_code;
81 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
82 break;
83 case RXRPC_CALL_LOCALLY_ABORTED:
84 tmp = call->abort_code;
85 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
86 break;
87 case RXRPC_CALL_NETWORK_ERROR:
David Howells3a927892017-04-06 10:11:56 +010088 tmp = -call->error;
David Howells248f2192016-09-08 11:10:12 +010089 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
90 break;
91 case RXRPC_CALL_LOCAL_ERROR:
David Howells3a927892017-04-06 10:11:56 +010092 tmp = -call->error;
David Howells248f2192016-09-08 11:10:12 +010093 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
94 break;
95 default:
96 pr_err("Invalid terminal call state %u\n", call->state);
97 BUG();
98 break;
99 }
100
David Howells84997902016-09-17 11:13:31 +0100101 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_terminal, call->rx_hard_ack,
102 call->rx_pkt_offset, call->rx_pkt_len, ret);
David Howells248f2192016-09-08 11:10:12 +0100103 return ret;
104}
105
106/*
107 * Pass back notification of a new call. The call is added to the
108 * to-be-accepted list. This means that the next call to be accepted might not
109 * be the last call seen awaiting acceptance, but unless we leave this on the
110 * front of the queue and block all other messages until someone gives us a
111 * user_ID for it, there's not a lot we can do.
112 */
113static int rxrpc_recvmsg_new_call(struct rxrpc_sock *rx,
114 struct rxrpc_call *call,
115 struct msghdr *msg, int flags)
116{
117 int tmp = 0, ret;
118
119 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &tmp);
120
121 if (ret == 0 && !(flags & MSG_PEEK)) {
122 _debug("to be accepted");
123 write_lock_bh(&rx->recvmsg_lock);
124 list_del_init(&call->recvmsg_link);
125 write_unlock_bh(&rx->recvmsg_lock);
126
David Howells3432a752016-09-13 09:05:14 +0100127 rxrpc_get_call(call, rxrpc_call_got);
David Howells248f2192016-09-08 11:10:12 +0100128 write_lock(&rx->call_lock);
129 list_add_tail(&call->accept_link, &rx->to_be_accepted);
130 write_unlock(&rx->call_lock);
131 }
132
David Howells84997902016-09-17 11:13:31 +0100133 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_to_be_accepted, 1, 0, 0, ret);
David Howells248f2192016-09-08 11:10:12 +0100134 return ret;
135}
136
137/*
138 * End the packet reception phase.
139 */
David Howellsb69d94d2016-09-24 18:05:27 +0100140static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
David Howells248f2192016-09-08 11:10:12 +0100141{
142 _enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
143
David Howells58dc63c2016-09-17 10:49:13 +0100144 trace_rxrpc_receive(call, rxrpc_receive_end, 0, call->rx_top);
David Howells816c9fc2016-09-17 10:49:11 +0100145 ASSERTCMP(call->rx_hard_ack, ==, call->rx_top);
146
David Howells248f2192016-09-08 11:10:12 +0100147 if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) {
David Howellsb69d94d2016-09-24 18:05:27 +0100148 rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, serial, true, false,
David Howells9c7ad432016-09-23 13:50:40 +0100149 rxrpc_propose_ack_terminal_ack);
David Howellsa5af7e12016-10-06 08:11:49 +0100150 rxrpc_send_ack_packet(call, false);
David Howells248f2192016-09-08 11:10:12 +0100151 }
152
153 write_lock_bh(&call->state_lock);
154
155 switch (call->state) {
156 case RXRPC_CALL_CLIENT_RECV_REPLY:
157 __rxrpc_call_completed(call);
David Howells9749fd22016-10-06 08:11:50 +0100158 write_unlock_bh(&call->state_lock);
David Howells248f2192016-09-08 11:10:12 +0100159 break;
160
161 case RXRPC_CALL_SERVER_RECV_REQUEST:
David Howells71f3ca42016-09-17 10:49:14 +0100162 call->tx_phase = true;
David Howells248f2192016-09-08 11:10:12 +0100163 call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
David Howells9749fd22016-10-06 08:11:50 +0100164 call->ack_at = call->expire_at;
165 write_unlock_bh(&call->state_lock);
166 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, 0, serial, false, true,
167 rxrpc_propose_ack_processing_op);
David Howells248f2192016-09-08 11:10:12 +0100168 break;
169 default:
David Howells9749fd22016-10-06 08:11:50 +0100170 write_unlock_bh(&call->state_lock);
David Howells248f2192016-09-08 11:10:12 +0100171 break;
172 }
David Howells248f2192016-09-08 11:10:12 +0100173}
174
175/*
176 * Discard a packet we've used up and advance the Rx window by one.
177 */
178static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
179{
David Howells816c9fc2016-09-17 10:49:11 +0100180 struct rxrpc_skb_priv *sp;
David Howells248f2192016-09-08 11:10:12 +0100181 struct sk_buff *skb;
David Howells58dc63c2016-09-17 10:49:13 +0100182 rxrpc_serial_t serial;
David Howells248f2192016-09-08 11:10:12 +0100183 rxrpc_seq_t hard_ack, top;
David Howells816c9fc2016-09-17 10:49:11 +0100184 u8 flags;
David Howells248f2192016-09-08 11:10:12 +0100185 int ix;
186
187 _enter("%d", call->debug_id);
188
189 hard_ack = call->rx_hard_ack;
190 top = smp_load_acquire(&call->rx_top);
191 ASSERT(before(hard_ack, top));
192
193 hard_ack++;
194 ix = hard_ack & RXRPC_RXTX_BUFF_MASK;
195 skb = call->rxtx_buffer[ix];
David Howells71f3ca42016-09-17 10:49:14 +0100196 rxrpc_see_skb(skb, rxrpc_skb_rx_rotated);
David Howells816c9fc2016-09-17 10:49:11 +0100197 sp = rxrpc_skb(skb);
198 flags = sp->hdr.flags;
David Howells58dc63c2016-09-17 10:49:13 +0100199 serial = sp->hdr.serial;
200 if (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO)
201 serial += (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) - 1;
202
David Howells248f2192016-09-08 11:10:12 +0100203 call->rxtx_buffer[ix] = NULL;
204 call->rxtx_annotations[ix] = 0;
205 /* Barrier against rxrpc_input_data(). */
206 smp_store_release(&call->rx_hard_ack, hard_ack);
207
David Howells71f3ca42016-09-17 10:49:14 +0100208 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
David Howells248f2192016-09-08 11:10:12 +0100209
David Howells816c9fc2016-09-17 10:49:11 +0100210 _debug("%u,%u,%02x", hard_ack, top, flags);
David Howells58dc63c2016-09-17 10:49:13 +0100211 trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
David Howells805b21b2016-09-24 18:05:26 +0100212 if (flags & RXRPC_LAST_PACKET) {
David Howellsb69d94d2016-09-24 18:05:27 +0100213 rxrpc_end_rx_phase(call, serial);
David Howells805b21b2016-09-24 18:05:26 +0100214 } else {
215 /* Check to see if there's an ACK that needs sending. */
216 if (after_eq(hard_ack, call->ackr_consumed + 2) ||
217 after_eq(top, call->ackr_seen + 2) ||
218 (hard_ack == top && after(hard_ack, call->ackr_consumed)))
219 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, 0, serial,
220 true, false,
221 rxrpc_propose_ack_rotate_rx);
222 if (call->ackr_reason)
David Howellsa5af7e12016-10-06 08:11:49 +0100223 rxrpc_send_ack_packet(call, false);
David Howells805b21b2016-09-24 18:05:26 +0100224 }
David Howells248f2192016-09-08 11:10:12 +0100225}
226
227/*
228 * Decrypt and verify a (sub)packet. The packet's length may be changed due to
229 * padding, but if this is the case, the packet length will be resident in the
230 * socket buffer. Note that we can't modify the master skb info as the skb may
231 * be the home to multiple subpackets.
232 */
233static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
234 u8 annotation,
235 unsigned int offset, unsigned int len)
236{
237 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
238 rxrpc_seq_t seq = sp->hdr.seq;
239 u16 cksum = sp->hdr.cksum;
240
241 _enter("");
242
243 /* For all but the head jumbo subpacket, the security checksum is in a
244 * jumbo header immediately prior to the data.
245 */
246 if ((annotation & RXRPC_RX_ANNO_JUMBO) > 1) {
247 __be16 tmp;
248 if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0)
249 BUG();
250 cksum = ntohs(tmp);
251 seq += (annotation & RXRPC_RX_ANNO_JUMBO) - 1;
252 }
253
254 return call->conn->security->verify_packet(call, skb, offset, len,
255 seq, cksum);
256}
257
258/*
259 * Locate the data within a packet. This is complicated by:
260 *
261 * (1) An skb may contain a jumbo packet - so we have to find the appropriate
262 * subpacket.
263 *
264 * (2) The (sub)packets may be encrypted and, if so, the encrypted portion
265 * contains an extra header which includes the true length of the data,
266 * excluding any encrypted padding.
267 */
268static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
269 u8 *_annotation,
270 unsigned int *_offset, unsigned int *_len)
271{
David Howells775e5b72016-09-30 13:26:03 +0100272 unsigned int offset = sizeof(struct rxrpc_wire_header);
David Howells248f2192016-09-08 11:10:12 +0100273 unsigned int len = *_len;
274 int ret;
275 u8 annotation = *_annotation;
276
David Howells248f2192016-09-08 11:10:12 +0100277 /* Locate the subpacket */
David Howells775e5b72016-09-30 13:26:03 +0100278 len = skb->len - offset;
David Howells248f2192016-09-08 11:10:12 +0100279 if ((annotation & RXRPC_RX_ANNO_JUMBO) > 0) {
280 offset += (((annotation & RXRPC_RX_ANNO_JUMBO) - 1) *
281 RXRPC_JUMBO_SUBPKTLEN);
282 len = (annotation & RXRPC_RX_ANNO_JLAST) ?
283 skb->len - offset : RXRPC_JUMBO_SUBPKTLEN;
284 }
285
286 if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) {
287 ret = rxrpc_verify_packet(call, skb, annotation, offset, len);
288 if (ret < 0)
289 return ret;
290 *_annotation |= RXRPC_RX_ANNO_VERIFIED;
291 }
292
293 *_offset = offset;
294 *_len = len;
295 call->conn->security->locate_data(call, skb, _offset, _len);
296 return 0;
297}
298
299/*
300 * Deliver messages to a call. This keeps processing packets until the buffer
301 * is filled and we find either more DATA (returns 0) or the end of the DATA
302 * (returns 1). If more packets are required, it returns -EAGAIN.
303 */
304static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
305 struct msghdr *msg, struct iov_iter *iter,
306 size_t len, int flags, size_t *_offset)
307{
308 struct rxrpc_skb_priv *sp;
309 struct sk_buff *skb;
310 rxrpc_seq_t hard_ack, top, seq;
311 size_t remain;
312 bool last;
313 unsigned int rx_pkt_offset, rx_pkt_len;
David Howells816c9fc2016-09-17 10:49:11 +0100314 int ix, copy, ret = -EAGAIN, ret2;
David Howells248f2192016-09-08 11:10:12 +0100315
David Howells248f2192016-09-08 11:10:12 +0100316 rx_pkt_offset = call->rx_pkt_offset;
317 rx_pkt_len = call->rx_pkt_len;
318
David Howells816c9fc2016-09-17 10:49:11 +0100319 if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
320 seq = call->rx_hard_ack;
321 ret = 1;
322 goto done;
323 }
324
David Howells248f2192016-09-08 11:10:12 +0100325 /* Barriers against rxrpc_input_data(). */
326 hard_ack = call->rx_hard_ack;
David Howellsd7e15832017-02-24 21:57:13 +0000327 seq = hard_ack + 1;
328 while (top = smp_load_acquire(&call->rx_top),
329 before_eq(seq, top)
330 ) {
David Howells248f2192016-09-08 11:10:12 +0100331 ix = seq & RXRPC_RXTX_BUFF_MASK;
332 skb = call->rxtx_buffer[ix];
David Howells84997902016-09-17 11:13:31 +0100333 if (!skb) {
334 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_hole, seq,
335 rx_pkt_offset, rx_pkt_len, 0);
David Howells248f2192016-09-08 11:10:12 +0100336 break;
David Howells84997902016-09-17 11:13:31 +0100337 }
David Howells248f2192016-09-08 11:10:12 +0100338 smp_rmb();
David Howells71f3ca42016-09-17 10:49:14 +0100339 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
David Howells248f2192016-09-08 11:10:12 +0100340 sp = rxrpc_skb(skb);
341
David Howells58dc63c2016-09-17 10:49:13 +0100342 if (!(flags & MSG_PEEK))
343 trace_rxrpc_receive(call, rxrpc_receive_front,
344 sp->hdr.serial, seq);
345
David Howells248f2192016-09-08 11:10:12 +0100346 if (msg)
347 sock_recv_timestamp(msg, sock->sk, skb);
348
David Howells2e2ea512016-09-17 10:49:11 +0100349 if (rx_pkt_offset == 0) {
David Howells816c9fc2016-09-17 10:49:11 +0100350 ret2 = rxrpc_locate_data(call, skb,
351 &call->rxtx_annotations[ix],
352 &rx_pkt_offset, &rx_pkt_len);
David Howells84997902016-09-17 11:13:31 +0100353 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_next, seq,
354 rx_pkt_offset, rx_pkt_len, ret2);
David Howells816c9fc2016-09-17 10:49:11 +0100355 if (ret2 < 0) {
356 ret = ret2;
David Howells2e2ea512016-09-17 10:49:11 +0100357 goto out;
David Howells816c9fc2016-09-17 10:49:11 +0100358 }
David Howells84997902016-09-17 11:13:31 +0100359 } else {
360 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_cont, seq,
361 rx_pkt_offset, rx_pkt_len, 0);
David Howells2e2ea512016-09-17 10:49:11 +0100362 }
David Howells248f2192016-09-08 11:10:12 +0100363
364 /* We have to handle short, empty and used-up DATA packets. */
365 remain = len - *_offset;
366 copy = rx_pkt_len;
367 if (copy > remain)
368 copy = remain;
369 if (copy > 0) {
David Howells816c9fc2016-09-17 10:49:11 +0100370 ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
371 copy);
372 if (ret2 < 0) {
373 ret = ret2;
David Howells248f2192016-09-08 11:10:12 +0100374 goto out;
David Howells816c9fc2016-09-17 10:49:11 +0100375 }
David Howells248f2192016-09-08 11:10:12 +0100376
377 /* handle piecemeal consumption of data packets */
David Howells248f2192016-09-08 11:10:12 +0100378 rx_pkt_offset += copy;
379 rx_pkt_len -= copy;
380 *_offset += copy;
381 }
382
383 if (rx_pkt_len > 0) {
David Howells84997902016-09-17 11:13:31 +0100384 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_full, seq,
385 rx_pkt_offset, rx_pkt_len, 0);
David Howells248f2192016-09-08 11:10:12 +0100386 ASSERTCMP(*_offset, ==, len);
David Howells816c9fc2016-09-17 10:49:11 +0100387 ret = 0;
David Howells248f2192016-09-08 11:10:12 +0100388 break;
389 }
390
391 /* The whole packet has been transferred. */
392 last = sp->hdr.flags & RXRPC_LAST_PACKET;
393 if (!(flags & MSG_PEEK))
394 rxrpc_rotate_rx_window(call);
395 rx_pkt_offset = 0;
396 rx_pkt_len = 0;
397
David Howells816c9fc2016-09-17 10:49:11 +0100398 if (last) {
399 ASSERTCMP(seq, ==, READ_ONCE(call->rx_top));
400 ret = 1;
401 goto out;
402 }
David Howellsd7e15832017-02-24 21:57:13 +0000403
404 seq++;
David Howells248f2192016-09-08 11:10:12 +0100405 }
406
David Howells248f2192016-09-08 11:10:12 +0100407out:
408 if (!(flags & MSG_PEEK)) {
409 call->rx_pkt_offset = rx_pkt_offset;
410 call->rx_pkt_len = rx_pkt_len;
411 }
David Howells816c9fc2016-09-17 10:49:11 +0100412done:
David Howells84997902016-09-17 11:13:31 +0100413 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_data_return, seq,
414 rx_pkt_offset, rx_pkt_len, ret);
David Howells248f2192016-09-08 11:10:12 +0100415 return ret;
416}
417
418/*
419 * Receive a message from an RxRPC socket
David Howells17926a72007-04-26 15:48:28 -0700420 * - we need to be careful about two or more threads calling recvmsg
421 * simultaneously
422 */
Ying Xue1b784142015-03-02 15:37:48 +0800423int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
424 int flags)
David Howells17926a72007-04-26 15:48:28 -0700425{
David Howells248f2192016-09-08 11:10:12 +0100426 struct rxrpc_call *call;
David Howells17926a72007-04-26 15:48:28 -0700427 struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
David Howells248f2192016-09-08 11:10:12 +0100428 struct list_head *l;
429 size_t copied = 0;
David Howells17926a72007-04-26 15:48:28 -0700430 long timeo;
David Howells248f2192016-09-08 11:10:12 +0100431 int ret;
David Howells17926a72007-04-26 15:48:28 -0700432
433 DEFINE_WAIT(wait);
434
David Howells84997902016-09-17 11:13:31 +0100435 trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_enter, 0, 0, 0, 0);
David Howells17926a72007-04-26 15:48:28 -0700436
437 if (flags & (MSG_OOB | MSG_TRUNC))
438 return -EOPNOTSUPP;
439
David Howells17926a72007-04-26 15:48:28 -0700440 timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
David Howells17926a72007-04-26 15:48:28 -0700441
David Howells248f2192016-09-08 11:10:12 +0100442try_again:
David Howells17926a72007-04-26 15:48:28 -0700443 lock_sock(&rx->sk);
444
David Howells248f2192016-09-08 11:10:12 +0100445 /* Return immediately if a client socket has no outstanding calls */
446 if (RB_EMPTY_ROOT(&rx->calls) &&
447 list_empty(&rx->recvmsg_q) &&
448 rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
449 release_sock(&rx->sk);
450 return -ENODATA;
451 }
452
453 if (list_empty(&rx->recvmsg_q)) {
454 ret = -EWOULDBLOCK;
David Howells84997902016-09-17 11:13:31 +0100455 if (timeo == 0) {
456 call = NULL;
David Howells248f2192016-09-08 11:10:12 +0100457 goto error_no_call;
David Howells84997902016-09-17 11:13:31 +0100458 }
David Howells248f2192016-09-08 11:10:12 +0100459
460 release_sock(&rx->sk);
461
462 /* Wait for something to happen */
463 prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
464 TASK_INTERRUPTIBLE);
465 ret = sock_error(&rx->sk);
466 if (ret)
467 goto wait_error;
468
469 if (list_empty(&rx->recvmsg_q)) {
470 if (signal_pending(current))
471 goto wait_interrupted;
David Howells84997902016-09-17 11:13:31 +0100472 trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_wait,
473 0, 0, 0, 0);
David Howells248f2192016-09-08 11:10:12 +0100474 timeo = schedule_timeout(timeo);
David Howells17926a72007-04-26 15:48:28 -0700475 }
David Howells248f2192016-09-08 11:10:12 +0100476 finish_wait(sk_sleep(&rx->sk), &wait);
477 goto try_again;
478 }
David Howells17926a72007-04-26 15:48:28 -0700479
David Howells248f2192016-09-08 11:10:12 +0100480 /* Find the next call and dequeue it if we're not just peeking. If we
481 * do dequeue it, that comes with a ref that we will need to release.
482 */
483 write_lock_bh(&rx->recvmsg_lock);
484 l = rx->recvmsg_q.next;
485 call = list_entry(l, struct rxrpc_call, recvmsg_link);
486 if (!(flags & MSG_PEEK))
487 list_del_init(&call->recvmsg_link);
488 else
David Howellsfff724292016-09-07 14:34:21 +0100489 rxrpc_get_call(call, rxrpc_call_got);
David Howells248f2192016-09-08 11:10:12 +0100490 write_unlock_bh(&rx->recvmsg_lock);
David Howells17926a72007-04-26 15:48:28 -0700491
David Howells84997902016-09-17 11:13:31 +0100492 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0);
David Howells17926a72007-04-26 15:48:28 -0700493
David Howells540b1c42017-02-27 15:43:06 +0000494 /* We're going to drop the socket lock, so we need to lock the call
495 * against interference by sendmsg.
496 */
497 if (!mutex_trylock(&call->user_mutex)) {
498 ret = -EWOULDBLOCK;
499 if (flags & MSG_DONTWAIT)
500 goto error_requeue_call;
501 ret = -ERESTARTSYS;
502 if (mutex_lock_interruptible(&call->user_mutex) < 0)
503 goto error_requeue_call;
504 }
505
506 release_sock(&rx->sk);
507
David Howells248f2192016-09-08 11:10:12 +0100508 if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
David Howells17926a72007-04-26 15:48:28 -0700509 BUG();
David Howells248f2192016-09-08 11:10:12 +0100510
511 if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
512 if (flags & MSG_CMSG_COMPAT) {
513 unsigned int id32 = call->user_call_ID;
514
515 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
516 sizeof(unsigned int), &id32);
517 } else {
518 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
519 sizeof(unsigned long),
520 &call->user_call_ID);
David Howellsf5c17aa2016-08-30 09:49:28 +0100521 }
David Howells248f2192016-09-08 11:10:12 +0100522 if (ret < 0)
David Howells540b1c42017-02-27 15:43:06 +0000523 goto error_unlock_call;
David Howells248f2192016-09-08 11:10:12 +0100524 }
525
526 if (msg->msg_name) {
David Howells68d6d1a2017-06-05 14:30:49 +0100527 struct sockaddr_rxrpc *srx = msg->msg_name;
528 size_t len = sizeof(call->peer->srx);
529
530 memcpy(msg->msg_name, &call->peer->srx, len);
531 srx->srx_service = call->service_id;
David Howells248f2192016-09-08 11:10:12 +0100532 msg->msg_namelen = len;
533 }
534
David Howells146d8fe2017-03-04 00:01:41 +0000535 switch (READ_ONCE(call->state)) {
David Howells248f2192016-09-08 11:10:12 +0100536 case RXRPC_CALL_SERVER_ACCEPTING:
537 ret = rxrpc_recvmsg_new_call(rx, call, msg, flags);
David Howells17926a72007-04-26 15:48:28 -0700538 break;
David Howells248f2192016-09-08 11:10:12 +0100539 case RXRPC_CALL_CLIENT_RECV_REPLY:
540 case RXRPC_CALL_SERVER_RECV_REQUEST:
541 case RXRPC_CALL_SERVER_ACK_REQUEST:
542 ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
543 flags, &copied);
544 if (ret == -EAGAIN)
545 ret = 0;
David Howells33b603f2016-09-13 22:36:21 +0100546
547 if (after(call->rx_top, call->rx_hard_ack) &&
548 call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK])
549 rxrpc_notify_socket(call);
David Howells17926a72007-04-26 15:48:28 -0700550 break;
551 default:
David Howells248f2192016-09-08 11:10:12 +0100552 ret = 0;
David Howells17926a72007-04-26 15:48:28 -0700553 break;
554 }
555
556 if (ret < 0)
David Howells540b1c42017-02-27 15:43:06 +0000557 goto error_unlock_call;
David Howells17926a72007-04-26 15:48:28 -0700558
David Howells248f2192016-09-08 11:10:12 +0100559 if (call->state == RXRPC_CALL_COMPLETE) {
560 ret = rxrpc_recvmsg_term(call, msg);
561 if (ret < 0)
David Howells540b1c42017-02-27 15:43:06 +0000562 goto error_unlock_call;
David Howells248f2192016-09-08 11:10:12 +0100563 if (!(flags & MSG_PEEK))
564 rxrpc_release_call(rx, call);
565 msg->msg_flags |= MSG_EOR;
566 ret = 1;
David Howells17926a72007-04-26 15:48:28 -0700567 }
568
David Howells248f2192016-09-08 11:10:12 +0100569 if (ret == 0)
570 msg->msg_flags |= MSG_MORE;
571 else
572 msg->msg_flags &= ~MSG_MORE;
573 ret = copied;
David Howells17926a72007-04-26 15:48:28 -0700574
David Howells540b1c42017-02-27 15:43:06 +0000575error_unlock_call:
576 mutex_unlock(&call->user_mutex);
David Howellsfff724292016-09-07 14:34:21 +0100577 rxrpc_put_call(call, rxrpc_call_put);
David Howells540b1c42017-02-27 15:43:06 +0000578 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
579 return ret;
580
581error_requeue_call:
582 if (!(flags & MSG_PEEK)) {
583 write_lock_bh(&rx->recvmsg_lock);
584 list_add(&call->recvmsg_link, &rx->recvmsg_q);
585 write_unlock_bh(&rx->recvmsg_lock);
586 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_requeue, 0, 0, 0, 0);
587 } else {
588 rxrpc_put_call(call, rxrpc_call_put);
589 }
David Howells248f2192016-09-08 11:10:12 +0100590error_no_call:
591 release_sock(&rx->sk);
David Howells84997902016-09-17 11:13:31 +0100592 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
David Howells17926a72007-04-26 15:48:28 -0700593 return ret;
594
David Howells17926a72007-04-26 15:48:28 -0700595wait_interrupted:
596 ret = sock_intr_errno(timeo);
597wait_error:
Eric Dumazet4a4771a2010-04-25 22:20:06 +0000598 finish_wait(sk_sleep(&rx->sk), &wait);
David Howells84997902016-09-17 11:13:31 +0100599 call = NULL;
600 goto error_no_call;
David Howellsd0016482016-08-30 20:42:14 +0100601}
David Howells651350d2007-04-26 15:50:17 -0700602
603/**
David Howellsd0016482016-08-30 20:42:14 +0100604 * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
605 * @sock: The socket that the call exists on
606 * @call: The call to send data through
607 * @buf: The buffer to receive into
608 * @size: The size of the buffer, including data already read
609 * @_offset: The running offset into the buffer.
610 * @want_more: True if more data is expected to be read
611 * @_abort: Where the abort code is stored if -ECONNABORTED is returned
David Howellsa68f4a22017-10-18 11:36:39 +0100612 * @_service: Where to store the actual service ID (may be upgraded)
David Howells651350d2007-04-26 15:50:17 -0700613 *
David Howellsd0016482016-08-30 20:42:14 +0100614 * Allow a kernel service to receive data and pick up information about the
615 * state of a call. Returns 0 if got what was asked for and there's more
616 * available, 1 if we got what was asked for and we're at the end of the data
617 * and -EAGAIN if we need more data.
618 *
619 * Note that we may return -EAGAIN to drain empty packets at the end of the
620 * data, even if we've already copied over the requested data.
621 *
622 * This function adds the amount it transfers to *_offset, so this should be
623 * precleared as appropriate. Note that the amount remaining in the buffer is
624 * taken to be size - *_offset.
625 *
626 * *_abort should also be initialised to 0.
David Howells651350d2007-04-26 15:50:17 -0700627 */
David Howellsd0016482016-08-30 20:42:14 +0100628int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
629 void *buf, size_t size, size_t *_offset,
David Howellsa68f4a22017-10-18 11:36:39 +0100630 bool want_more, u32 *_abort, u16 *_service)
David Howells651350d2007-04-26 15:50:17 -0700631{
David Howellsd0016482016-08-30 20:42:14 +0100632 struct iov_iter iter;
633 struct kvec iov;
634 int ret;
David Howells651350d2007-04-26 15:50:17 -0700635
David Howells248f2192016-09-08 11:10:12 +0100636 _enter("{%d,%s},%zu/%zu,%d",
637 call->debug_id, rxrpc_call_states[call->state],
638 *_offset, size, want_more);
David Howellsd0016482016-08-30 20:42:14 +0100639
640 ASSERTCMP(*_offset, <=, size);
641 ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING);
642
643 iov.iov_base = buf + *_offset;
644 iov.iov_len = size - *_offset;
645 iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset);
646
David Howells540b1c42017-02-27 15:43:06 +0000647 mutex_lock(&call->user_mutex);
David Howellsd0016482016-08-30 20:42:14 +0100648
David Howells146d8fe2017-03-04 00:01:41 +0000649 switch (READ_ONCE(call->state)) {
David Howellsd0016482016-08-30 20:42:14 +0100650 case RXRPC_CALL_CLIENT_RECV_REPLY:
651 case RXRPC_CALL_SERVER_RECV_REQUEST:
652 case RXRPC_CALL_SERVER_ACK_REQUEST:
David Howells248f2192016-09-08 11:10:12 +0100653 ret = rxrpc_recvmsg_data(sock, call, NULL, &iter, size, 0,
654 _offset);
David Howellsd0016482016-08-30 20:42:14 +0100655 if (ret < 0)
656 goto out;
657
658 /* We can only reach here with a partially full buffer if we
659 * have reached the end of the data. We must otherwise have a
660 * full buffer or have been given -EAGAIN.
661 */
662 if (ret == 1) {
663 if (*_offset < size)
664 goto short_data;
665 if (!want_more)
666 goto read_phase_complete;
667 ret = 0;
668 goto out;
669 }
670
671 if (!want_more)
672 goto excess_data;
673 goto out;
674
675 case RXRPC_CALL_COMPLETE:
676 goto call_complete;
677
678 default:
David Howellsd0016482016-08-30 20:42:14 +0100679 ret = -EINPROGRESS;
680 goto out;
681 }
682
683read_phase_complete:
684 ret = 1;
685out:
David Howellsa68f4a22017-10-18 11:36:39 +0100686 if (_service)
687 *_service = call->service_id;
David Howells540b1c42017-02-27 15:43:06 +0000688 mutex_unlock(&call->user_mutex);
David Howellsd0016482016-08-30 20:42:14 +0100689 _leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
690 return ret;
691
692short_data:
David Howellsfb46f6e2017-04-06 10:12:00 +0100693 trace_rxrpc_rx_eproto(call, 0, tracepoint_string("short_data"));
David Howellsd0016482016-08-30 20:42:14 +0100694 ret = -EBADMSG;
695 goto out;
696excess_data:
David Howellsfb46f6e2017-04-06 10:12:00 +0100697 trace_rxrpc_rx_eproto(call, 0, tracepoint_string("excess_data"));
David Howellsd0016482016-08-30 20:42:14 +0100698 ret = -EMSGSIZE;
699 goto out;
700call_complete:
701 *_abort = call->abort_code;
David Howells3a927892017-04-06 10:11:56 +0100702 ret = call->error;
David Howellsd0016482016-08-30 20:42:14 +0100703 if (call->completion == RXRPC_CALL_SUCCEEDED) {
704 ret = 1;
705 if (size > 0)
706 ret = -ECONNRESET;
707 }
708 goto out;
David Howells651350d2007-04-26 15:50:17 -0700709}
David Howellsd0016482016-08-30 20:42:14 +0100710EXPORT_SYMBOL(rxrpc_kernel_recv_data);