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Linux/net/rxrpc/ar-output.c

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  1 /* RxRPC packet transmission
  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/gfp.h>
 14 #include <linux/skbuff.h>
 15 #include <linux/circ_buf.h>
 16 #include <linux/export.h>
 17 #include <net/sock.h>
 18 #include <net/af_rxrpc.h>
 19 #include "ar-internal.h"
 20 
 21 int rxrpc_resend_timeout = 4;
 22 
 23 static int rxrpc_send_data(struct kiocb *iocb,
 24                            struct rxrpc_sock *rx,
 25                            struct rxrpc_call *call,
 26                            struct msghdr *msg, size_t len);
 27 
 28 /*
 29  * extract control messages from the sendmsg() control buffer
 30  */
 31 static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 32                               unsigned long *user_call_ID,
 33                               enum rxrpc_command *command,
 34                               u32 *abort_code,
 35                               bool server)
 36 {
 37         struct cmsghdr *cmsg;
 38         int len;
 39 
 40         *command = RXRPC_CMD_SEND_DATA;
 41 
 42         if (msg->msg_controllen == 0)
 43                 return -EINVAL;
 44 
 45         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 46                 if (!CMSG_OK(msg, cmsg))
 47                         return -EINVAL;
 48 
 49                 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
 50                 _debug("CMSG %d, %d, %d",
 51                        cmsg->cmsg_level, cmsg->cmsg_type, len);
 52 
 53                 if (cmsg->cmsg_level != SOL_RXRPC)
 54                         continue;
 55 
 56                 switch (cmsg->cmsg_type) {
 57                 case RXRPC_USER_CALL_ID:
 58                         if (msg->msg_flags & MSG_CMSG_COMPAT) {
 59                                 if (len != sizeof(u32))
 60                                         return -EINVAL;
 61                                 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
 62                         } else {
 63                                 if (len != sizeof(unsigned long))
 64                                         return -EINVAL;
 65                                 *user_call_ID = *(unsigned long *)
 66                                         CMSG_DATA(cmsg);
 67                         }
 68                         _debug("User Call ID %lx", *user_call_ID);
 69                         break;
 70 
 71                 case RXRPC_ABORT:
 72                         if (*command != RXRPC_CMD_SEND_DATA)
 73                                 return -EINVAL;
 74                         *command = RXRPC_CMD_SEND_ABORT;
 75                         if (len != sizeof(*abort_code))
 76                                 return -EINVAL;
 77                         *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
 78                         _debug("Abort %x", *abort_code);
 79                         if (*abort_code == 0)
 80                                 return -EINVAL;
 81                         break;
 82 
 83                 case RXRPC_ACCEPT:
 84                         if (*command != RXRPC_CMD_SEND_DATA)
 85                                 return -EINVAL;
 86                         *command = RXRPC_CMD_ACCEPT;
 87                         if (len != 0)
 88                                 return -EINVAL;
 89                         if (!server)
 90                                 return -EISCONN;
 91                         break;
 92 
 93                 default:
 94                         return -EINVAL;
 95                 }
 96         }
 97 
 98         _leave(" = 0");
 99         return 0;
100 }
101 
102 /*
103  * abort a call, sending an ABORT packet to the peer
104  */
105 static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
106 {
107         write_lock_bh(&call->state_lock);
108 
109         if (call->state <= RXRPC_CALL_COMPLETE) {
110                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
111                 call->abort_code = abort_code;
112                 set_bit(RXRPC_CALL_ABORT, &call->events);
113                 del_timer_sync(&call->resend_timer);
114                 del_timer_sync(&call->ack_timer);
115                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
116                 clear_bit(RXRPC_CALL_ACK, &call->events);
117                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
118                 rxrpc_queue_call(call);
119         }
120 
121         write_unlock_bh(&call->state_lock);
122 }
123 
124 /*
125  * send a message forming part of a client call through an RxRPC socket
126  * - caller holds the socket locked
127  * - the socket may be either a client socket or a server socket
128  */
129 int rxrpc_client_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
130                          struct rxrpc_transport *trans, struct msghdr *msg,
131                          size_t len)
132 {
133         struct rxrpc_conn_bundle *bundle;
134         enum rxrpc_command cmd;
135         struct rxrpc_call *call;
136         unsigned long user_call_ID = 0;
137         struct key *key;
138         __be16 service_id;
139         u32 abort_code = 0;
140         int ret;
141 
142         _enter("");
143 
144         ASSERT(trans != NULL);
145 
146         ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
147                                  false);
148         if (ret < 0)
149                 return ret;
150 
151         bundle = NULL;
152         if (trans) {
153                 service_id = rx->service_id;
154                 if (msg->msg_name) {
155                         struct sockaddr_rxrpc *srx =
156                                 (struct sockaddr_rxrpc *) msg->msg_name;
157                         service_id = htons(srx->srx_service);
158                 }
159                 key = rx->key;
160                 if (key && !rx->key->payload.data)
161                         key = NULL;
162                 bundle = rxrpc_get_bundle(rx, trans, key, service_id,
163                                           GFP_KERNEL);
164                 if (IS_ERR(bundle))
165                         return PTR_ERR(bundle);
166         }
167 
168         call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
169                                      abort_code == 0, GFP_KERNEL);
170         if (trans)
171                 rxrpc_put_bundle(trans, bundle);
172         if (IS_ERR(call)) {
173                 _leave(" = %ld", PTR_ERR(call));
174                 return PTR_ERR(call);
175         }
176 
177         _debug("CALL %d USR %lx ST %d on CONN %p",
178                call->debug_id, call->user_call_ID, call->state, call->conn);
179 
180         if (call->state >= RXRPC_CALL_COMPLETE) {
181                 /* it's too late for this call */
182                 ret = -ESHUTDOWN;
183         } else if (cmd == RXRPC_CMD_SEND_ABORT) {
184                 rxrpc_send_abort(call, abort_code);
185         } else if (cmd != RXRPC_CMD_SEND_DATA) {
186                 ret = -EINVAL;
187         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
188                 /* request phase complete for this client call */
189                 ret = -EPROTO;
190         } else {
191                 ret = rxrpc_send_data(iocb, rx, call, msg, len);
192         }
193 
194         rxrpc_put_call(call);
195         _leave(" = %d", ret);
196         return ret;
197 }
198 
199 /**
200  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
201  * @call: The call to send data through
202  * @msg: The data to send
203  * @len: The amount of data to send
204  *
205  * Allow a kernel service to send data on a call.  The call must be in an state
206  * appropriate to sending data.  No control data should be supplied in @msg,
207  * nor should an address be supplied.  MSG_MORE should be flagged if there's
208  * more data to come, otherwise this data will end the transmission phase.
209  */
210 int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
211                            size_t len)
212 {
213         int ret;
214 
215         _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
216 
217         ASSERTCMP(msg->msg_name, ==, NULL);
218         ASSERTCMP(msg->msg_control, ==, NULL);
219 
220         lock_sock(&call->socket->sk);
221 
222         _debug("CALL %d USR %lx ST %d on CONN %p",
223                call->debug_id, call->user_call_ID, call->state, call->conn);
224 
225         if (call->state >= RXRPC_CALL_COMPLETE) {
226                 ret = -ESHUTDOWN; /* it's too late for this call */
227         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
228                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
229                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
230                 ret = -EPROTO; /* request phase complete for this client call */
231         } else {
232                 mm_segment_t oldfs = get_fs();
233                 set_fs(KERNEL_DS);
234                 ret = rxrpc_send_data(NULL, call->socket, call, msg, len);
235                 set_fs(oldfs);
236         }
237 
238         release_sock(&call->socket->sk);
239         _leave(" = %d", ret);
240         return ret;
241 }
242 
243 EXPORT_SYMBOL(rxrpc_kernel_send_data);
244 
245 /**
246  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
247  * @call: The call to be aborted
248  * @abort_code: The abort code to stick into the ABORT packet
249  *
250  * Allow a kernel service to abort a call, if it's still in an abortable state.
251  */
252 void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
253 {
254         _enter("{%d},%d", call->debug_id, abort_code);
255 
256         lock_sock(&call->socket->sk);
257 
258         _debug("CALL %d USR %lx ST %d on CONN %p",
259                call->debug_id, call->user_call_ID, call->state, call->conn);
260 
261         if (call->state < RXRPC_CALL_COMPLETE)
262                 rxrpc_send_abort(call, abort_code);
263 
264         release_sock(&call->socket->sk);
265         _leave("");
266 }
267 
268 EXPORT_SYMBOL(rxrpc_kernel_abort_call);
269 
270 /*
271  * send a message through a server socket
272  * - caller holds the socket locked
273  */
274 int rxrpc_server_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
275                          struct msghdr *msg, size_t len)
276 {
277         enum rxrpc_command cmd;
278         struct rxrpc_call *call;
279         unsigned long user_call_ID = 0;
280         u32 abort_code = 0;
281         int ret;
282 
283         _enter("");
284 
285         ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
286                                  true);
287         if (ret < 0)
288                 return ret;
289 
290         if (cmd == RXRPC_CMD_ACCEPT) {
291                 call = rxrpc_accept_call(rx, user_call_ID);
292                 if (IS_ERR(call))
293                         return PTR_ERR(call);
294                 rxrpc_put_call(call);
295                 return 0;
296         }
297 
298         call = rxrpc_find_server_call(rx, user_call_ID);
299         if (!call)
300                 return -EBADSLT;
301         if (call->state >= RXRPC_CALL_COMPLETE) {
302                 ret = -ESHUTDOWN;
303                 goto out;
304         }
305 
306         switch (cmd) {
307         case RXRPC_CMD_SEND_DATA:
308                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
309                     call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
310                     call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
311                         /* Tx phase not yet begun for this call */
312                         ret = -EPROTO;
313                         break;
314                 }
315 
316                 ret = rxrpc_send_data(iocb, rx, call, msg, len);
317                 break;
318 
319         case RXRPC_CMD_SEND_ABORT:
320                 rxrpc_send_abort(call, abort_code);
321                 break;
322         default:
323                 BUG();
324         }
325 
326         out:
327         rxrpc_put_call(call);
328         _leave(" = %d", ret);
329         return ret;
330 }
331 
332 /*
333  * send a packet through the transport endpoint
334  */
335 int rxrpc_send_packet(struct rxrpc_transport *trans, struct sk_buff *skb)
336 {
337         struct kvec iov[1];
338         struct msghdr msg;
339         int ret, opt;
340 
341         _enter(",{%d}", skb->len);
342 
343         iov[0].iov_base = skb->head;
344         iov[0].iov_len = skb->len;
345 
346         msg.msg_name = &trans->peer->srx.transport.sin;
347         msg.msg_namelen = sizeof(trans->peer->srx.transport.sin);
348         msg.msg_control = NULL;
349         msg.msg_controllen = 0;
350         msg.msg_flags = 0;
351 
352         /* send the packet with the don't fragment bit set if we currently
353          * think it's small enough */
354         if (skb->len - sizeof(struct rxrpc_header) < trans->peer->maxdata) {
355                 down_read(&trans->local->defrag_sem);
356                 /* send the packet by UDP
357                  * - returns -EMSGSIZE if UDP would have to fragment the packet
358                  *   to go out of the interface
359                  *   - in which case, we'll have processed the ICMP error
360                  *     message and update the peer record
361                  */
362                 ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
363                                      iov[0].iov_len);
364 
365                 up_read(&trans->local->defrag_sem);
366                 if (ret == -EMSGSIZE)
367                         goto send_fragmentable;
368 
369                 _leave(" = %d [%u]", ret, trans->peer->maxdata);
370                 return ret;
371         }
372 
373 send_fragmentable:
374         /* attempt to send this message with fragmentation enabled */
375         _debug("send fragment");
376 
377         down_write(&trans->local->defrag_sem);
378         opt = IP_PMTUDISC_DONT;
379         ret = kernel_setsockopt(trans->local->socket, SOL_IP, IP_MTU_DISCOVER,
380                                 (char *) &opt, sizeof(opt));
381         if (ret == 0) {
382                 ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
383                                      iov[0].iov_len);
384 
385                 opt = IP_PMTUDISC_DO;
386                 kernel_setsockopt(trans->local->socket, SOL_IP,
387                                   IP_MTU_DISCOVER, (char *) &opt, sizeof(opt));
388         }
389 
390         up_write(&trans->local->defrag_sem);
391         _leave(" = %d [frag %u]", ret, trans->peer->maxdata);
392         return ret;
393 }
394 
395 /*
396  * wait for space to appear in the transmit/ACK window
397  * - caller holds the socket locked
398  */
399 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
400                                     struct rxrpc_call *call,
401                                     long *timeo)
402 {
403         DECLARE_WAITQUEUE(myself, current);
404         int ret;
405 
406         _enter(",{%d},%ld",
407                CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),
408                *timeo);
409 
410         add_wait_queue(&call->tx_waitq, &myself);
411 
412         for (;;) {
413                 set_current_state(TASK_INTERRUPTIBLE);
414                 ret = 0;
415                 if (CIRC_SPACE(call->acks_head, call->acks_tail,
416                                call->acks_winsz) > 0)
417                         break;
418                 if (signal_pending(current)) {
419                         ret = sock_intr_errno(*timeo);
420                         break;
421                 }
422 
423                 release_sock(&rx->sk);
424                 *timeo = schedule_timeout(*timeo);
425                 lock_sock(&rx->sk);
426         }
427 
428         remove_wait_queue(&call->tx_waitq, &myself);
429         set_current_state(TASK_RUNNING);
430         _leave(" = %d", ret);
431         return ret;
432 }
433 
434 /*
435  * attempt to schedule an instant Tx resend
436  */
437 static inline void rxrpc_instant_resend(struct rxrpc_call *call)
438 {
439         read_lock_bh(&call->state_lock);
440         if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
441                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
442                 if (call->state < RXRPC_CALL_COMPLETE &&
443                     !test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
444                         rxrpc_queue_call(call);
445         }
446         read_unlock_bh(&call->state_lock);
447 }
448 
449 /*
450  * queue a packet for transmission, set the resend timer and attempt
451  * to send the packet immediately
452  */
453 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
454                                bool last)
455 {
456         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
457         int ret;
458 
459         _net("queue skb %p [%d]", skb, call->acks_head);
460 
461         ASSERT(call->acks_window != NULL);
462         call->acks_window[call->acks_head] = (unsigned long) skb;
463         smp_wmb();
464         call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
465 
466         if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
467                 _debug("________awaiting reply/ACK__________");
468                 write_lock_bh(&call->state_lock);
469                 switch (call->state) {
470                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
471                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
472                         break;
473                 case RXRPC_CALL_SERVER_ACK_REQUEST:
474                         call->state = RXRPC_CALL_SERVER_SEND_REPLY;
475                         if (!last)
476                                 break;
477                 case RXRPC_CALL_SERVER_SEND_REPLY:
478                         call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
479                         break;
480                 default:
481                         break;
482                 }
483                 write_unlock_bh(&call->state_lock);
484         }
485 
486         _proto("Tx DATA %%%u { #%u }",
487                ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
488 
489         sp->need_resend = false;
490         sp->resend_at = jiffies + rxrpc_resend_timeout * HZ;
491         if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
492                 _debug("run timer");
493                 call->resend_timer.expires = sp->resend_at;
494                 add_timer(&call->resend_timer);
495         }
496 
497         /* attempt to cancel the rx-ACK timer, deferring reply transmission if
498          * we're ACK'ing the request phase of an incoming call */
499         ret = -EAGAIN;
500         if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
501                 /* the packet may be freed by rxrpc_process_call() before this
502                  * returns */
503                 ret = rxrpc_send_packet(call->conn->trans, skb);
504                 _net("sent skb %p", skb);
505         } else {
506                 _debug("failed to delete ACK timer");
507         }
508 
509         if (ret < 0) {
510                 _debug("need instant resend %d", ret);
511                 sp->need_resend = true;
512                 rxrpc_instant_resend(call);
513         }
514 
515         _leave("");
516 }
517 
518 /*
519  * send data through a socket
520  * - must be called in process context
521  * - caller holds the socket locked
522  */
523 static int rxrpc_send_data(struct kiocb *iocb,
524                            struct rxrpc_sock *rx,
525                            struct rxrpc_call *call,
526                            struct msghdr *msg, size_t len)
527 {
528         struct rxrpc_skb_priv *sp;
529         unsigned char __user *from;
530         struct sk_buff *skb;
531         struct iovec *iov;
532         struct sock *sk = &rx->sk;
533         long timeo;
534         bool more;
535         int ret, ioc, segment, copied;
536 
537         _enter(",,,{%zu},%zu", msg->msg_iovlen, len);
538 
539         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
540 
541         /* this should be in poll */
542         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
543 
544         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
545                 return -EPIPE;
546 
547         iov = msg->msg_iov;
548         ioc = msg->msg_iovlen - 1;
549         from = iov->iov_base;
550         segment = iov->iov_len;
551         iov++;
552         more = msg->msg_flags & MSG_MORE;
553 
554         skb = call->tx_pending;
555         call->tx_pending = NULL;
556 
557         copied = 0;
558         do {
559                 int copy;
560 
561                 if (segment > len)
562                         segment = len;
563 
564                 _debug("SEGMENT %d @%p", segment, from);
565 
566                 if (!skb) {
567                         size_t size, chunk, max, space;
568 
569                         _debug("alloc");
570 
571                         if (CIRC_SPACE(call->acks_head, call->acks_tail,
572                                        call->acks_winsz) <= 0) {
573                                 ret = -EAGAIN;
574                                 if (msg->msg_flags & MSG_DONTWAIT)
575                                         goto maybe_error;
576                                 ret = rxrpc_wait_for_tx_window(rx, call,
577                                                                &timeo);
578                                 if (ret < 0)
579                                         goto maybe_error;
580                         }
581 
582                         max = call->conn->trans->peer->maxdata;
583                         max -= call->conn->security_size;
584                         max &= ~(call->conn->size_align - 1UL);
585 
586                         chunk = max;
587                         if (chunk > len && !more)
588                                 chunk = len;
589 
590                         space = chunk + call->conn->size_align;
591                         space &= ~(call->conn->size_align - 1UL);
592 
593                         size = space + call->conn->header_size;
594 
595                         _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
596 
597                         /* create a buffer that we can retain until it's ACK'd */
598                         skb = sock_alloc_send_skb(
599                                 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
600                         if (!skb)
601                                 goto maybe_error;
602 
603                         rxrpc_new_skb(skb);
604 
605                         _debug("ALLOC SEND %p", skb);
606 
607                         ASSERTCMP(skb->mark, ==, 0);
608 
609                         _debug("HS: %u", call->conn->header_size);
610                         skb_reserve(skb, call->conn->header_size);
611                         skb->len += call->conn->header_size;
612 
613                         sp = rxrpc_skb(skb);
614                         sp->remain = chunk;
615                         if (sp->remain > skb_tailroom(skb))
616                                 sp->remain = skb_tailroom(skb);
617 
618                         _net("skb: hr %d, tr %d, hl %d, rm %d",
619                                skb_headroom(skb),
620                                skb_tailroom(skb),
621                                skb_headlen(skb),
622                                sp->remain);
623 
624                         skb->ip_summed = CHECKSUM_UNNECESSARY;
625                 }
626 
627                 _debug("append");
628                 sp = rxrpc_skb(skb);
629 
630                 /* append next segment of data to the current buffer */
631                 copy = skb_tailroom(skb);
632                 ASSERTCMP(copy, >, 0);
633                 if (copy > segment)
634                         copy = segment;
635                 if (copy > sp->remain)
636                         copy = sp->remain;
637 
638                 _debug("add");
639                 ret = skb_add_data(skb, from, copy);
640                 _debug("added");
641                 if (ret < 0)
642                         goto efault;
643                 sp->remain -= copy;
644                 skb->mark += copy;
645                 copied += copy;
646 
647                 len -= copy;
648                 segment -= copy;
649                 from += copy;
650                 while (segment == 0 && ioc > 0) {
651                         from = iov->iov_base;
652                         segment = iov->iov_len;
653                         iov++;
654                         ioc--;
655                 }
656                 if (len == 0) {
657                         segment = 0;
658                         ioc = 0;
659                 }
660 
661                 /* check for the far side aborting the call or a network error
662                  * occurring */
663                 if (call->state > RXRPC_CALL_COMPLETE)
664                         goto call_aborted;
665 
666                 /* add the packet to the send queue if it's now full */
667                 if (sp->remain <= 0 || (segment == 0 && !more)) {
668                         struct rxrpc_connection *conn = call->conn;
669                         size_t pad;
670 
671                         /* pad out if we're using security */
672                         if (conn->security) {
673                                 pad = conn->security_size + skb->mark;
674                                 pad = conn->size_align - pad;
675                                 pad &= conn->size_align - 1;
676                                 _debug("pad %zu", pad);
677                                 if (pad)
678                                         memset(skb_put(skb, pad), 0, pad);
679                         }
680 
681                         sp->hdr.epoch = conn->epoch;
682                         sp->hdr.cid = call->cid;
683                         sp->hdr.callNumber = call->call_id;
684                         sp->hdr.seq =
685                                 htonl(atomic_inc_return(&call->sequence));
686                         sp->hdr.serial =
687                                 htonl(atomic_inc_return(&conn->serial));
688                         sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
689                         sp->hdr.userStatus = 0;
690                         sp->hdr.securityIndex = conn->security_ix;
691                         sp->hdr._rsvd = 0;
692                         sp->hdr.serviceId = conn->service_id;
693 
694                         sp->hdr.flags = conn->out_clientflag;
695                         if (len == 0 && !more)
696                                 sp->hdr.flags |= RXRPC_LAST_PACKET;
697                         else if (CIRC_SPACE(call->acks_head, call->acks_tail,
698                                             call->acks_winsz) > 1)
699                                 sp->hdr.flags |= RXRPC_MORE_PACKETS;
700 
701                         ret = rxrpc_secure_packet(
702                                 call, skb, skb->mark,
703                                 skb->head + sizeof(struct rxrpc_header));
704                         if (ret < 0)
705                                 goto out;
706 
707                         memcpy(skb->head, &sp->hdr,
708                                sizeof(struct rxrpc_header));
709                         rxrpc_queue_packet(call, skb, segment == 0 && !more);
710                         skb = NULL;
711                 }
712 
713         } while (segment > 0);
714 
715 success:
716         ret = copied;
717 out:
718         call->tx_pending = skb;
719         _leave(" = %d", ret);
720         return ret;
721 
722 call_aborted:
723         rxrpc_free_skb(skb);
724         if (call->state == RXRPC_CALL_NETWORK_ERROR)
725                 ret = call->conn->trans->peer->net_error;
726         else
727                 ret = -ECONNABORTED;
728         _leave(" = %d", ret);
729         return ret;
730 
731 maybe_error:
732         if (copied)
733                 goto success;
734         goto out;
735 
736 efault:
737         ret = -EFAULT;
738         goto out;
739 }
740 

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