net/rxrpc/ar-output.c

   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 /*
  22  * Time till packet resend (in jiffies).
  23  */
  24 unsigned rxrpc_resend_timeout = 4 * HZ;
  25
  26 static int rxrpc_send_data(struct kiocb *iocb,
  27                            struct rxrpc_sock *rx,
  28                            struct rxrpc_call *call,
  29                            struct msghdr *msg, size_t len);
  30
  31 /*
  32  * extract control messages from the sendmsg() control buffer
  33  */
  34 static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
  35                               unsigned long *user_call_ID,
  36                               enum rxrpc_command *command,
  37                               u32 *abort_code,
  38                               bool server)
  39 {
  40         struct cmsghdr *cmsg;
  41         int len;
  42
  43         *command = RXRPC_CMD_SEND_DATA;
  44
  45         if (msg->msg_controllen == 0)
  46                 return -EINVAL;
  47
  48         for_each_cmsghdr(cmsg, msg) {
  49                 if (!CMSG_OK(msg, cmsg))
  50                         return -EINVAL;
  51
  52                 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
  53                 _debug("CMSG %d, %d, %d",
  54                        cmsg->cmsg_level, cmsg->cmsg_type, len);
  55
  56                 if (cmsg->cmsg_level != SOL_RXRPC)
  57                         continue;
  58
  59                 switch (cmsg->cmsg_type) {
  60                 case RXRPC_USER_CALL_ID:
  61                         if (msg->msg_flags & MSG_CMSG_COMPAT) {
  62                                 if (len != sizeof(u32))
  63                                         return -EINVAL;
  64                                 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
  65                         } else {
  66                                 if (len != sizeof(unsigned long))
  67                                         return -EINVAL;
  68                                 *user_call_ID = *(unsigned long *)
  69                                         CMSG_DATA(cmsg);
  70                         }
  71                         _debug("User Call ID %lx", *user_call_ID);
  72                         break;
  73
  74                 case RXRPC_ABORT:
  75                         if (*command != RXRPC_CMD_SEND_DATA)
  76                                 return -EINVAL;
  77                         *command = RXRPC_CMD_SEND_ABORT;
  78                         if (len != sizeof(*abort_code))
  79                                 return -EINVAL;
  80                         *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
  81                         _debug("Abort %x", *abort_code);
  82                         if (*abort_code == 0)
  83                                 return -EINVAL;
  84                         break;
  85
  86                 case RXRPC_ACCEPT:
  87                         if (*command != RXRPC_CMD_SEND_DATA)
  88                                 return -EINVAL;
  89                         *command = RXRPC_CMD_ACCEPT;
  90                         if (len != 0)
  91                                 return -EINVAL;
  92                         if (!server)
  93                                 return -EISCONN;
  94                         break;
  95
  96                 default:
  97                         return -EINVAL;
  98                 }
  99         }
 100
 101         _leave(" = 0");
 102         return 0;
 103 }
 104
 105 /*
 106  * abort a call, sending an ABORT packet to the peer
 107  */
 108 static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
 109 {
 110         write_lock_bh(&call->state_lock);
 111
 112         if (call->state <= RXRPC_CALL_COMPLETE) {
 113                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 114                 call->abort_code = abort_code;
 115                 set_bit(RXRPC_CALL_ABORT, &call->events);
 116                 del_timer_sync(&call->resend_timer);
 117                 del_timer_sync(&call->ack_timer);
 118                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 119                 clear_bit(RXRPC_CALL_ACK, &call->events);
 120                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 121                 rxrpc_queue_call(call);
 122         }
 123
 124         write_unlock_bh(&call->state_lock);
 125 }
 126
 127 /*
 128  * send a message forming part of a client call through an RxRPC socket
 129  * - caller holds the socket locked
 130  * - the socket may be either a client socket or a server socket
 131  */
 132 int rxrpc_client_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
 133                          struct rxrpc_transport *trans, struct msghdr *msg,
 134                          size_t len)
 135 {
 136         struct rxrpc_conn_bundle *bundle;
 137         enum rxrpc_command cmd;
 138         struct rxrpc_call *call;
 139         unsigned long user_call_ID = 0;
 140         struct key *key;
 141         __be16 service_id;
 142         u32 abort_code = 0;
 143         int ret;
 144
 145         _enter("");
 146
 147         ASSERT(trans != NULL);
 148
 149         ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
 150                                  false);
 151         if (ret < 0)
 152                 return ret;
 153
 154         bundle = NULL;
 155         if (trans) {
 156                 service_id = rx->service_id;
 157                 if (msg->msg_name) {
 158                         DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx,
 159                                          msg->msg_name);
 160                         service_id = htons(srx->srx_service);
 161                 }
 162                 key = rx->key;
 163                 if (key && !rx->key->payload.data)
 164                         key = NULL;
 165                 bundle = rxrpc_get_bundle(rx, trans, key, service_id,
 166                                           GFP_KERNEL);
 167                 if (IS_ERR(bundle))
 168                         return PTR_ERR(bundle);
 169         }
 170
 171         call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
 172                                      abort_code == 0, GFP_KERNEL);
 173         if (trans)
 174                 rxrpc_put_bundle(trans, bundle);
 175         if (IS_ERR(call)) {
 176                 _leave(" = %ld", PTR_ERR(call));
 177                 return PTR_ERR(call);
 178         }
 179
 180         _debug("CALL %d USR %lx ST %d on CONN %p",
 181                call->debug_id, call->user_call_ID, call->state, call->conn);
 182
 183         if (call->state >= RXRPC_CALL_COMPLETE) {
 184                 /* it's too late for this call */
 185                 ret = -ESHUTDOWN;
 186         } else if (cmd == RXRPC_CMD_SEND_ABORT) {
 187                 rxrpc_send_abort(call, abort_code);
 188         } else if (cmd != RXRPC_CMD_SEND_DATA) {
 189                 ret = -EINVAL;
 190         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
 191                 /* request phase complete for this client call */
 192                 ret = -EPROTO;
 193         } else {
 194                 ret = rxrpc_send_data(iocb, rx, call, msg, len);
 195         }
 196
 197         rxrpc_put_call(call);
 198         _leave(" = %d", ret);
 199         return ret;
 200 }
 201
 202 /**
 203  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
 204  * @call: The call to send data through
 205  * @msg: The data to send
 206  * @len: The amount of data to send
 207  *
 208  * Allow a kernel service to send data on a call.  The call must be in an state
 209  * appropriate to sending data.  No control data should be supplied in @msg,
 210  * nor should an address be supplied.  MSG_MORE should be flagged if there's
 211  * more data to come, otherwise this data will end the transmission phase.
 212  */
 213 int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
 214                            size_t len)
 215 {
 216         int ret;
 217
 218         _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
 219
 220         ASSERTCMP(msg->msg_name, ==, NULL);
 221         ASSERTCMP(msg->msg_control, ==, NULL);
 222
 223         lock_sock(&call->socket->sk);
 224
 225         _debug("CALL %d USR %lx ST %d on CONN %p",
 226                call->debug_id, call->user_call_ID, call->state, call->conn);
 227
 228         if (call->state >= RXRPC_CALL_COMPLETE) {
 229                 ret = -ESHUTDOWN; /* it's too late for this call */
 230         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 231                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 232                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 233                 ret = -EPROTO; /* request phase complete for this client call */
 234         } else {
 235                 ret = rxrpc_send_data(NULL, call->socket, call, msg, len);
 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;
 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         struct sk_buff *skb;
 530         struct sock *sk = &rx->sk;
 531         long timeo;
 532         bool more;
 533         int ret, copied;
 534
 535         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 536
 537         /* this should be in poll */
 538         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 539
 540         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 541                 return -EPIPE;
 542
 543         more = msg->msg_flags & MSG_MORE;
 544
 545         skb = call->tx_pending;
 546         call->tx_pending = NULL;
 547
 548         copied = 0;
 549         if (len > iov_iter_count(&msg->msg_iter))
 550                 len = iov_iter_count(&msg->msg_iter);
 551         while (len) {
 552                 int copy;
 553
 554                 if (!skb) {
 555                         size_t size, chunk, max, space;
 556
 557                         _debug("alloc");
 558
 559                         if (CIRC_SPACE(call->acks_head, call->acks_tail,
 560                                        call->acks_winsz) <= 0) {
 561                                 ret = -EAGAIN;
 562                                 if (msg->msg_flags & MSG_DONTWAIT)
 563                                         goto maybe_error;
 564                                 ret = rxrpc_wait_for_tx_window(rx, call,
 565                                                                &timeo);
 566                                 if (ret < 0)
 567                                         goto maybe_error;
 568                         }
 569
 570                         max = call->conn->trans->peer->maxdata;
 571                         max -= call->conn->security_size;
 572                         max &= ~(call->conn->size_align - 1UL);
 573
 574                         chunk = max;
 575                         if (chunk > len && !more)
 576                                 chunk = len;
 577
 578                         space = chunk + call->conn->size_align;
 579                         space &= ~(call->conn->size_align - 1UL);
 580
 581                         size = space + call->conn->header_size;
 582
 583                         _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
 584
 585                         /* create a buffer that we can retain until it's ACK'd */
 586                         skb = sock_alloc_send_skb(
 587                                 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
 588                         if (!skb)
 589                                 goto maybe_error;
 590
 591                         rxrpc_new_skb(skb);
 592
 593                         _debug("ALLOC SEND %p", skb);
 594
 595                         ASSERTCMP(skb->mark, ==, 0);
 596
 597                         _debug("HS: %u", call->conn->header_size);
 598                         skb_reserve(skb, call->conn->header_size);
 599                         skb->len += call->conn->header_size;
 600
 601                         sp = rxrpc_skb(skb);
 602                         sp->remain = chunk;
 603                         if (sp->remain > skb_tailroom(skb))
 604                                 sp->remain = skb_tailroom(skb);
 605
 606                         _net("skb: hr %d, tr %d, hl %d, rm %d",
 607                                skb_headroom(skb),
 608                                skb_tailroom(skb),
 609                                skb_headlen(skb),
 610                                sp->remain);
 611
 612                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 613                 }
 614
 615                 _debug("append");
 616                 sp = rxrpc_skb(skb);
 617
 618                 /* append next segment of data to the current buffer */
 619                 copy = skb_tailroom(skb);
 620                 ASSERTCMP(copy, >, 0);
 621                 if (copy > len)
 622                         copy = len;
 623                 if (copy > sp->remain)
 624                         copy = sp->remain;
 625
 626                 _debug("add");
 627                 ret = skb_add_data(skb, &msg->msg_iter, copy);
 628                 _debug("added");
 629                 if (ret < 0)
 630                         goto efault;
 631                 sp->remain -= copy;
 632                 skb->mark += copy;
 633                 copied += copy;
 634
 635                 len -= copy;
 636
 637                 /* check for the far side aborting the call or a network error
 638                  * occurring */
 639                 if (call->state > RXRPC_CALL_COMPLETE)
 640                         goto call_aborted;
 641
 642                 /* add the packet to the send queue if it's now full */
 643                 if (sp->remain <= 0 || (!len && !more)) {
 644                         struct rxrpc_connection *conn = call->conn;
 645                         uint32_t seq;
 646                         size_t pad;
 647
 648                         /* pad out if we're using security */
 649                         if (conn->security) {
 650                                 pad = conn->security_size + skb->mark;
 651                                 pad = conn->size_align - pad;
 652                                 pad &= conn->size_align - 1;
 653                                 _debug("pad %zu", pad);
 654                                 if (pad)
 655                                         memset(skb_put(skb, pad), 0, pad);
 656                         }
 657
 658                         seq = atomic_inc_return(&call->sequence);
 659
 660                         sp->hdr.epoch = conn->epoch;
 661                         sp->hdr.cid = call->cid;
 662                         sp->hdr.callNumber = call->call_id;
 663                         sp->hdr.seq = htonl(seq);
 664                         sp->hdr.serial =
 665                                 htonl(atomic_inc_return(&conn->serial));
 666                         sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
 667                         sp->hdr.userStatus = 0;
 668                         sp->hdr.securityIndex = conn->security_ix;
 669                         sp->hdr._rsvd = 0;
 670                         sp->hdr.serviceId = conn->service_id;
 671
 672                         sp->hdr.flags = conn->out_clientflag;
 673                         if (len == 0 && !more)
 674                                 sp->hdr.flags |= RXRPC_LAST_PACKET;
 675                         else if (CIRC_SPACE(call->acks_head, call->acks_tail,
 676                                             call->acks_winsz) > 1)
 677                                 sp->hdr.flags |= RXRPC_MORE_PACKETS;
 678                         if (more && seq & 1)
 679                                 sp->hdr.flags |= RXRPC_REQUEST_ACK;
 680
 681                         ret = rxrpc_secure_packet(
 682                                 call, skb, skb->mark,
 683                                 skb->head + sizeof(struct rxrpc_header));
 684                         if (ret < 0)
 685                                 goto out;
 686
 687                         memcpy(skb->head, &sp->hdr,
 688                                sizeof(struct rxrpc_header));
 689                         rxrpc_queue_packet(call, skb, !iov_iter_count(&msg->msg_iter) && !more);
 690                         skb = NULL;
 691                 }
 692         }
 693
 694 success:
 695         ret = copied;
 696 out:
 697         call->tx_pending = skb;
 698         _leave(" = %d", ret);
 699         return ret;
 700
 701 call_aborted:
 702         rxrpc_free_skb(skb);
 703         if (call->state == RXRPC_CALL_NETWORK_ERROR)
 704                 ret = call->conn->trans->peer->net_error;
 705         else
 706                 ret = -ECONNABORTED;
 707         _leave(" = %d", ret);
 708         return ret;
 709
 710 maybe_error:
 711         if (copied)
 712                 goto success;
 713         goto out;
 714
 715 efault:
 716         ret = -EFAULT;
 717         goto out;
 718 }