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