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1/* 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
12#include <linux/net.h>
13#include <linux/skbuff.h>
14#include <linux/export.h>
15#include <net/sock.h>
16#include <net/af_rxrpc.h>
17#include "ar-internal.h"
18
19/*
20 * removal a call's user ID from the socket tree to make the user ID available
21 * again and so that it won't be seen again in association with that call
22 */
23void rxrpc_remove_user_ID(struct rxrpc_sock *rx, struct rxrpc_call *call)
24{
25 _debug("RELEASE CALL %d", call->debug_id);
26
27 if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
28 write_lock_bh(&rx->call_lock);
29 rb_erase(&call->sock_node, &call->socket->calls);
30 clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
31 write_unlock_bh(&rx->call_lock);
32 }
33
34 read_lock_bh(&call->state_lock);
35 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
36 !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
37 rxrpc_queue_call(call);
38 read_unlock_bh(&call->state_lock);
39}
40
41/*
42 * receive a message from an RxRPC socket
43 * - we need to be careful about two or more threads calling recvmsg
44 * simultaneously
45 */
46int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock,
47 struct msghdr *msg, size_t len, int flags)
48{
49 struct rxrpc_skb_priv *sp;
50 struct rxrpc_call *call = NULL, *continue_call = NULL;
51 struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
52 struct sk_buff *skb;
53 long timeo;
54 int copy, ret, ullen, offset, copied = 0;
55 u32 abort_code;
56
57 DEFINE_WAIT(wait);
58
59 _enter(",,,%zu,%d", len, flags);
60
61 if (flags & (MSG_OOB | MSG_TRUNC))
62 return -EOPNOTSUPP;
63
64 ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
65
66 timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
67 msg->msg_flags |= MSG_MORE;
68
69 lock_sock(&rx->sk);
70
71 for (;;) {
72 /* return immediately if a client socket has no outstanding
73 * calls */
74 if (RB_EMPTY_ROOT(&rx->calls)) {
75 if (copied)
76 goto out;
77 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
78 release_sock(&rx->sk);
79 if (continue_call)
80 rxrpc_put_call(continue_call);
81 return -ENODATA;
82 }
83 }
84
85 /* get the next message on the Rx queue */
86 skb = skb_peek(&rx->sk.sk_receive_queue);
87 if (!skb) {
88 /* nothing remains on the queue */
89 if (copied &&
90 (msg->msg_flags & MSG_PEEK || timeo == 0))
91 goto out;
92
93 /* wait for a message to turn up */
94 release_sock(&rx->sk);
95 prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
96 TASK_INTERRUPTIBLE);
97 ret = sock_error(&rx->sk);
98 if (ret)
99 goto wait_error;
100
101 if (skb_queue_empty(&rx->sk.sk_receive_queue)) {
102 if (signal_pending(current))
103 goto wait_interrupted;
104 timeo = schedule_timeout(timeo);
105 }
106 finish_wait(sk_sleep(&rx->sk), &wait);
107 lock_sock(&rx->sk);
108 continue;
109 }
110
111 peek_next_packet:
112 sp = rxrpc_skb(skb);
113 call = sp->call;
114 ASSERT(call != NULL);
115
116 _debug("next pkt %s", rxrpc_pkts[sp->hdr.type]);
117
118 /* make sure we wait for the state to be updated in this call */
119 spin_lock_bh(&call->lock);
120 spin_unlock_bh(&call->lock);
121
122 if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
123 _debug("packet from released call");
124 if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
125 BUG();
126 rxrpc_free_skb(skb);
127 continue;
128 }
129
130 /* determine whether to continue last data receive */
131 if (continue_call) {
132 _debug("maybe cont");
133 if (call != continue_call ||
134 skb->mark != RXRPC_SKB_MARK_DATA) {
135 release_sock(&rx->sk);
136 rxrpc_put_call(continue_call);
137 _leave(" = %d [noncont]", copied);
138 return copied;
139 }
140 }
141
142 rxrpc_get_call(call);
143
144 /* copy the peer address and timestamp */
145 if (!continue_call) {
146 if (msg->msg_name && msg->msg_namelen > 0)
147 memcpy(msg->msg_name,
148 &call->conn->trans->peer->srx,
149 sizeof(call->conn->trans->peer->srx));
150 sock_recv_ts_and_drops(msg, &rx->sk, skb);
151 }
152
153 /* receive the message */
154 if (skb->mark != RXRPC_SKB_MARK_DATA)
155 goto receive_non_data_message;
156
157 _debug("recvmsg DATA #%u { %d, %d }",
158 ntohl(sp->hdr.seq), skb->len, sp->offset);
159
160 if (!continue_call) {
161 /* only set the control data once per recvmsg() */
162 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
163 ullen, &call->user_call_ID);
164 if (ret < 0)
165 goto copy_error;
166 ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
167 }
168
169 ASSERTCMP(ntohl(sp->hdr.seq), >=, call->rx_data_recv);
170 ASSERTCMP(ntohl(sp->hdr.seq), <=, call->rx_data_recv + 1);
171 call->rx_data_recv = ntohl(sp->hdr.seq);
172
173 ASSERTCMP(ntohl(sp->hdr.seq), >, call->rx_data_eaten);
174
175 offset = sp->offset;
176 copy = skb->len - offset;
177 if (copy > len - copied)
178 copy = len - copied;
179
180 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
181 ret = skb_copy_datagram_iovec(skb, offset,
182 msg->msg_iov, copy);
183 } else {
184 ret = skb_copy_and_csum_datagram_iovec(skb, offset,
185 msg->msg_iov);
186 if (ret == -EINVAL)
187 goto csum_copy_error;
188 }
189
190 if (ret < 0)
191 goto copy_error;
192
193 /* handle piecemeal consumption of data packets */
194 _debug("copied %d+%d", copy, copied);
195
196 offset += copy;
197 copied += copy;
198
199 if (!(flags & MSG_PEEK))
200 sp->offset = offset;
201
202 if (sp->offset < skb->len) {
203 _debug("buffer full");
204 ASSERTCMP(copied, ==, len);
205 break;
206 }
207
208 /* we transferred the whole data packet */
209 if (sp->hdr.flags & RXRPC_LAST_PACKET) {
210 _debug("last");
211 if (call->conn->out_clientflag) {
212 /* last byte of reply received */
213 ret = copied;
214 goto terminal_message;
215 }
216
217 /* last bit of request received */
218 if (!(flags & MSG_PEEK)) {
219 _debug("eat packet");
220 if (skb_dequeue(&rx->sk.sk_receive_queue) !=
221 skb)
222 BUG();
223 rxrpc_free_skb(skb);
224 }
225 msg->msg_flags &= ~MSG_MORE;
226 break;
227 }
228
229 /* move on to the next data message */
230 _debug("next");
231 if (!continue_call)
232 continue_call = sp->call;
233 else
234 rxrpc_put_call(call);
235 call = NULL;
236
237 if (flags & MSG_PEEK) {
238 _debug("peek next");
239 skb = skb->next;
240 if (skb == (struct sk_buff *) &rx->sk.sk_receive_queue)
241 break;
242 goto peek_next_packet;
243 }
244
245 _debug("eat packet");
246 if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
247 BUG();
248 rxrpc_free_skb(skb);
249 }
250
251 /* end of non-terminal data packet reception for the moment */
252 _debug("end rcv data");
253out:
254 release_sock(&rx->sk);
255 if (call)
256 rxrpc_put_call(call);
257 if (continue_call)
258 rxrpc_put_call(continue_call);
259 _leave(" = %d [data]", copied);
260 return copied;
261
262 /* handle non-DATA messages such as aborts, incoming connections and
263 * final ACKs */
264receive_non_data_message:
265 _debug("non-data");
266
267 if (skb->mark == RXRPC_SKB_MARK_NEW_CALL) {
268 _debug("RECV NEW CALL");
269 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &abort_code);
270 if (ret < 0)
271 goto copy_error;
272 if (!(flags & MSG_PEEK)) {
273 if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
274 BUG();
275 rxrpc_free_skb(skb);
276 }
277 goto out;
278 }
279
280 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
281 ullen, &call->user_call_ID);
282 if (ret < 0)
283 goto copy_error;
284 ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
285
286 switch (skb->mark) {
287 case RXRPC_SKB_MARK_DATA:
288 BUG();
289 case RXRPC_SKB_MARK_FINAL_ACK:
290 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
291 break;
292 case RXRPC_SKB_MARK_BUSY:
293 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
294 break;
295 case RXRPC_SKB_MARK_REMOTE_ABORT:
296 abort_code = call->abort_code;
297 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
298 break;
299 case RXRPC_SKB_MARK_NET_ERROR:
300 _debug("RECV NET ERROR %d", sp->error);
301 abort_code = sp->error;
302 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &abort_code);
303 break;
304 case RXRPC_SKB_MARK_LOCAL_ERROR:
305 _debug("RECV LOCAL ERROR %d", sp->error);
306 abort_code = sp->error;
307 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
308 &abort_code);
309 break;
310 default:
311 BUG();
312 break;
313 }
314
315 if (ret < 0)
316 goto copy_error;
317
318terminal_message:
319 _debug("terminal");
320 msg->msg_flags &= ~MSG_MORE;
321 msg->msg_flags |= MSG_EOR;
322
323 if (!(flags & MSG_PEEK)) {
324 _net("free terminal skb %p", skb);
325 if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
326 BUG();
327 rxrpc_free_skb(skb);
328 rxrpc_remove_user_ID(rx, call);
329 }
330
331 release_sock(&rx->sk);
332 rxrpc_put_call(call);
333 if (continue_call)
334 rxrpc_put_call(continue_call);
335 _leave(" = %d", ret);
336 return ret;
337
338copy_error:
339 _debug("copy error");
340 release_sock(&rx->sk);
341 rxrpc_put_call(call);
342 if (continue_call)
343 rxrpc_put_call(continue_call);
344 _leave(" = %d", ret);
345 return ret;
346
347csum_copy_error:
348 _debug("csum error");
349 release_sock(&rx->sk);
350 if (continue_call)
351 rxrpc_put_call(continue_call);
352 rxrpc_kill_skb(skb);
353 skb_kill_datagram(&rx->sk, skb, flags);
354 rxrpc_put_call(call);
355 return -EAGAIN;
356
357wait_interrupted:
358 ret = sock_intr_errno(timeo);
359wait_error:
360 finish_wait(sk_sleep(&rx->sk), &wait);
361 if (continue_call)
362 rxrpc_put_call(continue_call);
363 if (copied)
364 copied = ret;
365 _leave(" = %d [waitfail %d]", copied, ret);
366 return copied;
367
368}
369
370/**
371 * rxrpc_kernel_data_delivered - Record delivery of data message
372 * @skb: Message holding data
373 *
374 * Record the delivery of a data message. This permits RxRPC to keep its
375 * tracking correct. The socket buffer will be deleted.
376 */
377void rxrpc_kernel_data_delivered(struct sk_buff *skb)
378{
379 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
380 struct rxrpc_call *call = sp->call;
381
382 ASSERTCMP(ntohl(sp->hdr.seq), >=, call->rx_data_recv);
383 ASSERTCMP(ntohl(sp->hdr.seq), <=, call->rx_data_recv + 1);
384 call->rx_data_recv = ntohl(sp->hdr.seq);
385
386 ASSERTCMP(ntohl(sp->hdr.seq), >, call->rx_data_eaten);
387 rxrpc_free_skb(skb);
388}
389
390EXPORT_SYMBOL(rxrpc_kernel_data_delivered);
391
392/**
393 * rxrpc_kernel_is_data_last - Determine if data message is last one
394 * @skb: Message holding data
395 *
396 * Determine if data message is last one for the parent call.
397 */
398bool rxrpc_kernel_is_data_last(struct sk_buff *skb)
399{
400 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
401
402 ASSERTCMP(skb->mark, ==, RXRPC_SKB_MARK_DATA);
403
404 return sp->hdr.flags & RXRPC_LAST_PACKET;
405}
406
407EXPORT_SYMBOL(rxrpc_kernel_is_data_last);
408
409/**
410 * rxrpc_kernel_get_abort_code - Get the abort code from an RxRPC abort message
411 * @skb: Message indicating an abort
412 *
413 * Get the abort code from an RxRPC abort message.
414 */
415u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb)
416{
417 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
418
419 ASSERTCMP(skb->mark, ==, RXRPC_SKB_MARK_REMOTE_ABORT);
420
421 return sp->call->abort_code;
422}
423
424EXPORT_SYMBOL(rxrpc_kernel_get_abort_code);
425
426/**
427 * rxrpc_kernel_get_error - Get the error number from an RxRPC error message
428 * @skb: Message indicating an error
429 *
430 * Get the error number from an RxRPC error message.
431 */
432int rxrpc_kernel_get_error_number(struct sk_buff *skb)
433{
434 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
435
436 return sp->error;
437}
438
439EXPORT_SYMBOL(rxrpc_kernel_get_error_number);