1 /* AF_RXRPC sendmsg() implementation. 2 * 3 * Copyright (C) 2007, 2016 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 Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/net.h> 15 #include <linux/gfp.h> 16 #include <linux/skbuff.h> 17 #include <linux/export.h> 18 #include <net/sock.h> 19 #include <net/af_rxrpc.h> 20 #include "ar-internal.h" 21 22 enum rxrpc_command { 23 RXRPC_CMD_SEND_DATA, /* send data message */ 24 RXRPC_CMD_SEND_ABORT, /* request abort generation */ 25 RXRPC_CMD_ACCEPT, /* [server] accept incoming call */ 26 RXRPC_CMD_REJECT_BUSY, /* [server] reject a call as busy */ 27 }; 28 29 /* 30 * wait for space to appear in the transmit/ACK window 31 * - caller holds the socket locked 32 */ 33 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx, 34 struct rxrpc_call *call, 35 long *timeo) 36 { 37 DECLARE_WAITQUEUE(myself, current); 38 int ret; 39 40 _enter(",{%u,%u,%u}", 41 call->tx_hard_ack, call->tx_top, call->tx_winsize); 42 43 add_wait_queue(&call->waitq, &myself); 44 45 for (;;) { 46 set_current_state(TASK_INTERRUPTIBLE); 47 ret = 0; 48 if (call->tx_top - call->tx_hard_ack < 49 min_t(unsigned int, call->tx_winsize, 50 call->cong_cwnd + call->cong_extra)) 51 break; 52 if (call->state >= RXRPC_CALL_COMPLETE) { 53 ret = -call->error; 54 break; 55 } 56 if (signal_pending(current)) { 57 ret = sock_intr_errno(*timeo); 58 break; 59 } 60 61 trace_rxrpc_transmit(call, rxrpc_transmit_wait); 62 release_sock(&rx->sk); 63 *timeo = schedule_timeout(*timeo); 64 lock_sock(&rx->sk); 65 } 66 67 remove_wait_queue(&call->waitq, &myself); 68 set_current_state(TASK_RUNNING); 69 _leave(" = %d", ret); 70 return ret; 71 } 72 73 /* 74 * Schedule an instant Tx resend. 75 */ 76 static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix) 77 { 78 spin_lock_bh(&call->lock); 79 80 if (call->state < RXRPC_CALL_COMPLETE) { 81 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS; 82 if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events)) 83 rxrpc_queue_call(call); 84 } 85 86 spin_unlock_bh(&call->lock); 87 } 88 89 /* 90 * Queue a DATA packet for transmission, set the resend timeout and send the 91 * packet immediately 92 */ 93 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb, 94 bool last) 95 { 96 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 97 rxrpc_seq_t seq = sp->hdr.seq; 98 int ret, ix; 99 u8 annotation = RXRPC_TX_ANNO_UNACK; 100 101 _net("queue skb %p [%d]", skb, seq); 102 103 ASSERTCMP(seq, ==, call->tx_top + 1); 104 105 if (last) 106 annotation |= RXRPC_TX_ANNO_LAST; 107 108 /* We have to set the timestamp before queueing as the retransmit 109 * algorithm can see the packet as soon as we queue it. 110 */ 111 skb->tstamp = ktime_get_real(); 112 113 ix = seq & RXRPC_RXTX_BUFF_MASK; 114 rxrpc_get_skb(skb, rxrpc_skb_tx_got); 115 call->rxtx_annotations[ix] = annotation; 116 smp_wmb(); 117 call->rxtx_buffer[ix] = skb; 118 call->tx_top = seq; 119 if (last) 120 trace_rxrpc_transmit(call, rxrpc_transmit_queue_last); 121 else 122 trace_rxrpc_transmit(call, rxrpc_transmit_queue); 123 124 if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) { 125 _debug("________awaiting reply/ACK__________"); 126 write_lock_bh(&call->state_lock); 127 switch (call->state) { 128 case RXRPC_CALL_CLIENT_SEND_REQUEST: 129 call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY; 130 break; 131 case RXRPC_CALL_SERVER_ACK_REQUEST: 132 call->state = RXRPC_CALL_SERVER_SEND_REPLY; 133 call->ack_at = call->expire_at; 134 if (call->ackr_reason == RXRPC_ACK_DELAY) 135 call->ackr_reason = 0; 136 __rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply, 137 ktime_get_real()); 138 if (!last) 139 break; 140 case RXRPC_CALL_SERVER_SEND_REPLY: 141 call->state = RXRPC_CALL_SERVER_AWAIT_ACK; 142 break; 143 default: 144 break; 145 } 146 write_unlock_bh(&call->state_lock); 147 } 148 149 if (seq == 1 && rxrpc_is_client_call(call)) 150 rxrpc_expose_client_call(call); 151 152 ret = rxrpc_send_data_packet(call, skb, false); 153 if (ret < 0) { 154 _debug("need instant resend %d", ret); 155 rxrpc_instant_resend(call, ix); 156 } else { 157 ktime_t now = ktime_get_real(), resend_at; 158 159 resend_at = ktime_add_ms(now, rxrpc_resend_timeout); 160 161 if (ktime_before(resend_at, call->resend_at)) { 162 call->resend_at = resend_at; 163 rxrpc_set_timer(call, rxrpc_timer_set_for_send, now); 164 } 165 } 166 167 rxrpc_free_skb(skb, rxrpc_skb_tx_freed); 168 _leave(""); 169 } 170 171 /* 172 * send data through a socket 173 * - must be called in process context 174 * - caller holds the socket locked 175 */ 176 static int rxrpc_send_data(struct rxrpc_sock *rx, 177 struct rxrpc_call *call, 178 struct msghdr *msg, size_t len) 179 { 180 struct rxrpc_skb_priv *sp; 181 struct sk_buff *skb; 182 struct sock *sk = &rx->sk; 183 long timeo; 184 bool more; 185 int ret, copied; 186 187 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 188 189 /* this should be in poll */ 190 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); 191 192 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 193 return -EPIPE; 194 195 more = msg->msg_flags & MSG_MORE; 196 197 skb = call->tx_pending; 198 call->tx_pending = NULL; 199 rxrpc_see_skb(skb, rxrpc_skb_tx_seen); 200 201 copied = 0; 202 do { 203 /* Check to see if there's a ping ACK to reply to. */ 204 if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE) 205 rxrpc_send_ack_packet(call, false); 206 207 if (!skb) { 208 size_t size, chunk, max, space; 209 210 _debug("alloc"); 211 212 if (call->tx_top - call->tx_hard_ack >= 213 min_t(unsigned int, call->tx_winsize, 214 call->cong_cwnd + call->cong_extra)) { 215 ret = -EAGAIN; 216 if (msg->msg_flags & MSG_DONTWAIT) 217 goto maybe_error; 218 ret = rxrpc_wait_for_tx_window(rx, call, 219 &timeo); 220 if (ret < 0) 221 goto maybe_error; 222 } 223 224 max = RXRPC_JUMBO_DATALEN; 225 max -= call->conn->security_size; 226 max &= ~(call->conn->size_align - 1UL); 227 228 chunk = max; 229 if (chunk > msg_data_left(msg) && !more) 230 chunk = msg_data_left(msg); 231 232 space = chunk + call->conn->size_align; 233 space &= ~(call->conn->size_align - 1UL); 234 235 size = space + call->conn->security_size; 236 237 _debug("SIZE: %zu/%zu/%zu", chunk, space, size); 238 239 /* create a buffer that we can retain until it's ACK'd */ 240 skb = sock_alloc_send_skb( 241 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret); 242 if (!skb) 243 goto maybe_error; 244 245 rxrpc_new_skb(skb, rxrpc_skb_tx_new); 246 247 _debug("ALLOC SEND %p", skb); 248 249 ASSERTCMP(skb->mark, ==, 0); 250 251 _debug("HS: %u", call->conn->security_size); 252 skb_reserve(skb, call->conn->security_size); 253 skb->len += call->conn->security_size; 254 255 sp = rxrpc_skb(skb); 256 sp->remain = chunk; 257 if (sp->remain > skb_tailroom(skb)) 258 sp->remain = skb_tailroom(skb); 259 260 _net("skb: hr %d, tr %d, hl %d, rm %d", 261 skb_headroom(skb), 262 skb_tailroom(skb), 263 skb_headlen(skb), 264 sp->remain); 265 266 skb->ip_summed = CHECKSUM_UNNECESSARY; 267 } 268 269 _debug("append"); 270 sp = rxrpc_skb(skb); 271 272 /* append next segment of data to the current buffer */ 273 if (msg_data_left(msg) > 0) { 274 int copy = skb_tailroom(skb); 275 ASSERTCMP(copy, >, 0); 276 if (copy > msg_data_left(msg)) 277 copy = msg_data_left(msg); 278 if (copy > sp->remain) 279 copy = sp->remain; 280 281 _debug("add"); 282 ret = skb_add_data(skb, &msg->msg_iter, copy); 283 _debug("added"); 284 if (ret < 0) 285 goto efault; 286 sp->remain -= copy; 287 skb->mark += copy; 288 copied += copy; 289 } 290 291 /* check for the far side aborting the call or a network error 292 * occurring */ 293 if (call->state == RXRPC_CALL_COMPLETE) 294 goto call_terminated; 295 296 /* add the packet to the send queue if it's now full */ 297 if (sp->remain <= 0 || 298 (msg_data_left(msg) == 0 && !more)) { 299 struct rxrpc_connection *conn = call->conn; 300 uint32_t seq; 301 size_t pad; 302 303 /* pad out if we're using security */ 304 if (conn->security_ix) { 305 pad = conn->security_size + skb->mark; 306 pad = conn->size_align - pad; 307 pad &= conn->size_align - 1; 308 _debug("pad %zu", pad); 309 if (pad) 310 memset(skb_put(skb, pad), 0, pad); 311 } 312 313 seq = call->tx_top + 1; 314 315 sp->hdr.seq = seq; 316 sp->hdr._rsvd = 0; 317 sp->hdr.flags = conn->out_clientflag; 318 319 if (msg_data_left(msg) == 0 && !more) 320 sp->hdr.flags |= RXRPC_LAST_PACKET; 321 else if (call->tx_top - call->tx_hard_ack < 322 call->tx_winsize) 323 sp->hdr.flags |= RXRPC_MORE_PACKETS; 324 325 ret = conn->security->secure_packet( 326 call, skb, skb->mark, skb->head); 327 if (ret < 0) 328 goto out; 329 330 rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more); 331 skb = NULL; 332 } 333 } while (msg_data_left(msg) > 0); 334 335 success: 336 ret = copied; 337 out: 338 call->tx_pending = skb; 339 _leave(" = %d", ret); 340 return ret; 341 342 call_terminated: 343 rxrpc_free_skb(skb, rxrpc_skb_tx_freed); 344 _leave(" = %d", -call->error); 345 return -call->error; 346 347 maybe_error: 348 if (copied) 349 goto success; 350 goto out; 351 352 efault: 353 ret = -EFAULT; 354 goto out; 355 } 356 357 /* 358 * extract control messages from the sendmsg() control buffer 359 */ 360 static int rxrpc_sendmsg_cmsg(struct msghdr *msg, 361 unsigned long *user_call_ID, 362 enum rxrpc_command *command, 363 u32 *abort_code, 364 bool *_exclusive) 365 { 366 struct cmsghdr *cmsg; 367 bool got_user_ID = false; 368 int len; 369 370 *command = RXRPC_CMD_SEND_DATA; 371 372 if (msg->msg_controllen == 0) 373 return -EINVAL; 374 375 for_each_cmsghdr(cmsg, msg) { 376 if (!CMSG_OK(msg, cmsg)) 377 return -EINVAL; 378 379 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr)); 380 _debug("CMSG %d, %d, %d", 381 cmsg->cmsg_level, cmsg->cmsg_type, len); 382 383 if (cmsg->cmsg_level != SOL_RXRPC) 384 continue; 385 386 switch (cmsg->cmsg_type) { 387 case RXRPC_USER_CALL_ID: 388 if (msg->msg_flags & MSG_CMSG_COMPAT) { 389 if (len != sizeof(u32)) 390 return -EINVAL; 391 *user_call_ID = *(u32 *) CMSG_DATA(cmsg); 392 } else { 393 if (len != sizeof(unsigned long)) 394 return -EINVAL; 395 *user_call_ID = *(unsigned long *) 396 CMSG_DATA(cmsg); 397 } 398 _debug("User Call ID %lx", *user_call_ID); 399 got_user_ID = true; 400 break; 401 402 case RXRPC_ABORT: 403 if (*command != RXRPC_CMD_SEND_DATA) 404 return -EINVAL; 405 *command = RXRPC_CMD_SEND_ABORT; 406 if (len != sizeof(*abort_code)) 407 return -EINVAL; 408 *abort_code = *(unsigned int *) CMSG_DATA(cmsg); 409 _debug("Abort %x", *abort_code); 410 if (*abort_code == 0) 411 return -EINVAL; 412 break; 413 414 case RXRPC_ACCEPT: 415 if (*command != RXRPC_CMD_SEND_DATA) 416 return -EINVAL; 417 *command = RXRPC_CMD_ACCEPT; 418 if (len != 0) 419 return -EINVAL; 420 break; 421 422 case RXRPC_EXCLUSIVE_CALL: 423 *_exclusive = true; 424 if (len != 0) 425 return -EINVAL; 426 break; 427 default: 428 return -EINVAL; 429 } 430 } 431 432 if (!got_user_ID) 433 return -EINVAL; 434 _leave(" = 0"); 435 return 0; 436 } 437 438 /* 439 * Create a new client call for sendmsg(). 440 */ 441 static struct rxrpc_call * 442 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, 443 unsigned long user_call_ID, bool exclusive) 444 { 445 struct rxrpc_conn_parameters cp; 446 struct rxrpc_call *call; 447 struct key *key; 448 449 DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name); 450 451 _enter(""); 452 453 if (!msg->msg_name) 454 return ERR_PTR(-EDESTADDRREQ); 455 456 key = rx->key; 457 if (key && !rx->key->payload.data[0]) 458 key = NULL; 459 460 memset(&cp, 0, sizeof(cp)); 461 cp.local = rx->local; 462 cp.key = rx->key; 463 cp.security_level = rx->min_sec_level; 464 cp.exclusive = rx->exclusive | exclusive; 465 cp.service_id = srx->srx_service; 466 call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL); 467 468 _leave(" = %p\n", call); 469 return call; 470 } 471 472 /* 473 * send a message forming part of a client call through an RxRPC socket 474 * - caller holds the socket locked 475 * - the socket may be either a client socket or a server socket 476 */ 477 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) 478 { 479 enum rxrpc_command cmd; 480 struct rxrpc_call *call; 481 unsigned long user_call_ID = 0; 482 bool exclusive = false; 483 u32 abort_code = 0; 484 int ret; 485 486 _enter(""); 487 488 ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code, 489 &exclusive); 490 if (ret < 0) 491 return ret; 492 493 if (cmd == RXRPC_CMD_ACCEPT) { 494 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) 495 return -EINVAL; 496 call = rxrpc_accept_call(rx, user_call_ID, NULL); 497 if (IS_ERR(call)) 498 return PTR_ERR(call); 499 rxrpc_put_call(call, rxrpc_call_put); 500 return 0; 501 } 502 503 call = rxrpc_find_call_by_user_ID(rx, user_call_ID); 504 if (!call) { 505 if (cmd != RXRPC_CMD_SEND_DATA) 506 return -EBADSLT; 507 call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID, 508 exclusive); 509 if (IS_ERR(call)) 510 return PTR_ERR(call); 511 } 512 513 _debug("CALL %d USR %lx ST %d on CONN %p", 514 call->debug_id, call->user_call_ID, call->state, call->conn); 515 516 if (call->state >= RXRPC_CALL_COMPLETE) { 517 /* it's too late for this call */ 518 ret = -ESHUTDOWN; 519 } else if (cmd == RXRPC_CMD_SEND_ABORT) { 520 ret = 0; 521 if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED)) 522 ret = rxrpc_send_abort_packet(call); 523 } else if (cmd != RXRPC_CMD_SEND_DATA) { 524 ret = -EINVAL; 525 } else if (rxrpc_is_client_call(call) && 526 call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) { 527 /* request phase complete for this client call */ 528 ret = -EPROTO; 529 } else if (rxrpc_is_service_call(call) && 530 call->state != RXRPC_CALL_SERVER_ACK_REQUEST && 531 call->state != RXRPC_CALL_SERVER_SEND_REPLY) { 532 /* Reply phase not begun or not complete for service call. */ 533 ret = -EPROTO; 534 } else { 535 ret = rxrpc_send_data(rx, call, msg, len); 536 } 537 538 rxrpc_put_call(call, rxrpc_call_put); 539 _leave(" = %d", ret); 540 return ret; 541 } 542 543 /** 544 * rxrpc_kernel_send_data - Allow a kernel service to send data on a call 545 * @sock: The socket the call is on 546 * @call: The call to send data through 547 * @msg: The data to send 548 * @len: The amount of data to send 549 * 550 * Allow a kernel service to send data on a call. The call must be in an state 551 * appropriate to sending data. No control data should be supplied in @msg, 552 * nor should an address be supplied. MSG_MORE should be flagged if there's 553 * more data to come, otherwise this data will end the transmission phase. 554 */ 555 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call, 556 struct msghdr *msg, size_t len) 557 { 558 int ret; 559 560 _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]); 561 562 ASSERTCMP(msg->msg_name, ==, NULL); 563 ASSERTCMP(msg->msg_control, ==, NULL); 564 565 lock_sock(sock->sk); 566 567 _debug("CALL %d USR %lx ST %d on CONN %p", 568 call->debug_id, call->user_call_ID, call->state, call->conn); 569 570 if (call->state >= RXRPC_CALL_COMPLETE) { 571 ret = -ESHUTDOWN; /* it's too late for this call */ 572 } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST && 573 call->state != RXRPC_CALL_SERVER_ACK_REQUEST && 574 call->state != RXRPC_CALL_SERVER_SEND_REPLY) { 575 ret = -EPROTO; /* request phase complete for this client call */ 576 } else { 577 ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len); 578 } 579 580 release_sock(sock->sk); 581 _leave(" = %d", ret); 582 return ret; 583 } 584 EXPORT_SYMBOL(rxrpc_kernel_send_data); 585 586 /** 587 * rxrpc_kernel_abort_call - Allow a kernel service to abort a call 588 * @sock: The socket the call is on 589 * @call: The call to be aborted 590 * @abort_code: The abort code to stick into the ABORT packet 591 * @error: Local error value 592 * @why: 3-char string indicating why. 593 * 594 * Allow a kernel service to abort a call, if it's still in an abortable state. 595 */ 596 void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call, 597 u32 abort_code, int error, const char *why) 598 { 599 _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why); 600 601 lock_sock(sock->sk); 602 603 if (rxrpc_abort_call(why, call, 0, abort_code, error)) 604 rxrpc_send_abort_packet(call); 605 606 release_sock(sock->sk); 607 _leave(""); 608 } 609 610 EXPORT_SYMBOL(rxrpc_kernel_abort_call); 611