1 /* RxRPC packet reception 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 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/module.h> 15 #include <linux/net.h> 16 #include <linux/skbuff.h> 17 #include <linux/errqueue.h> 18 #include <linux/udp.h> 19 #include <linux/in.h> 20 #include <linux/in6.h> 21 #include <linux/icmp.h> 22 #include <linux/gfp.h> 23 #include <net/sock.h> 24 #include <net/af_rxrpc.h> 25 #include <net/ip.h> 26 #include <net/udp.h> 27 #include <net/net_namespace.h> 28 #include "ar-internal.h" 29 30 static void rxrpc_proto_abort(const char *why, 31 struct rxrpc_call *call, rxrpc_seq_t seq) 32 { 33 if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, EBADMSG)) { 34 set_bit(RXRPC_CALL_EV_ABORT, &call->events); 35 rxrpc_queue_call(call); 36 } 37 } 38 39 /* 40 * Do TCP-style congestion management [RFC 5681]. 41 */ 42 static void rxrpc_congestion_management(struct rxrpc_call *call, 43 struct sk_buff *skb, 44 struct rxrpc_ack_summary *summary, 45 rxrpc_serial_t acked_serial) 46 { 47 enum rxrpc_congest_change change = rxrpc_cong_no_change; 48 unsigned int cumulative_acks = call->cong_cumul_acks; 49 unsigned int cwnd = call->cong_cwnd; 50 bool resend = false; 51 52 summary->flight_size = 53 (call->tx_top - call->tx_hard_ack) - summary->nr_acks; 54 55 if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) { 56 summary->retrans_timeo = true; 57 call->cong_ssthresh = max_t(unsigned int, 58 summary->flight_size / 2, 2); 59 cwnd = 1; 60 if (cwnd >= call->cong_ssthresh && 61 call->cong_mode == RXRPC_CALL_SLOW_START) { 62 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; 63 call->cong_tstamp = skb->tstamp; 64 cumulative_acks = 0; 65 } 66 } 67 68 cumulative_acks += summary->nr_new_acks; 69 cumulative_acks += summary->nr_rot_new_acks; 70 if (cumulative_acks > 255) 71 cumulative_acks = 255; 72 73 summary->mode = call->cong_mode; 74 summary->cwnd = call->cong_cwnd; 75 summary->ssthresh = call->cong_ssthresh; 76 summary->cumulative_acks = cumulative_acks; 77 summary->dup_acks = call->cong_dup_acks; 78 79 switch (call->cong_mode) { 80 case RXRPC_CALL_SLOW_START: 81 if (summary->nr_nacks > 0) 82 goto packet_loss_detected; 83 if (summary->cumulative_acks > 0) 84 cwnd += 1; 85 if (cwnd >= call->cong_ssthresh) { 86 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; 87 call->cong_tstamp = skb->tstamp; 88 } 89 goto out; 90 91 case RXRPC_CALL_CONGEST_AVOIDANCE: 92 if (summary->nr_nacks > 0) 93 goto packet_loss_detected; 94 95 /* We analyse the number of packets that get ACK'd per RTT 96 * period and increase the window if we managed to fill it. 97 */ 98 if (call->peer->rtt_usage == 0) 99 goto out; 100 if (ktime_before(skb->tstamp, 101 ktime_add_ns(call->cong_tstamp, 102 call->peer->rtt))) 103 goto out_no_clear_ca; 104 change = rxrpc_cong_rtt_window_end; 105 call->cong_tstamp = skb->tstamp; 106 if (cumulative_acks >= cwnd) 107 cwnd++; 108 goto out; 109 110 case RXRPC_CALL_PACKET_LOSS: 111 if (summary->nr_nacks == 0) 112 goto resume_normality; 113 114 if (summary->new_low_nack) { 115 change = rxrpc_cong_new_low_nack; 116 call->cong_dup_acks = 1; 117 if (call->cong_extra > 1) 118 call->cong_extra = 1; 119 goto send_extra_data; 120 } 121 122 call->cong_dup_acks++; 123 if (call->cong_dup_acks < 3) 124 goto send_extra_data; 125 126 change = rxrpc_cong_begin_retransmission; 127 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT; 128 call->cong_ssthresh = max_t(unsigned int, 129 summary->flight_size / 2, 2); 130 cwnd = call->cong_ssthresh + 3; 131 call->cong_extra = 0; 132 call->cong_dup_acks = 0; 133 resend = true; 134 goto out; 135 136 case RXRPC_CALL_FAST_RETRANSMIT: 137 if (!summary->new_low_nack) { 138 if (summary->nr_new_acks == 0) 139 cwnd += 1; 140 call->cong_dup_acks++; 141 if (call->cong_dup_acks == 2) { 142 change = rxrpc_cong_retransmit_again; 143 call->cong_dup_acks = 0; 144 resend = true; 145 } 146 } else { 147 change = rxrpc_cong_progress; 148 cwnd = call->cong_ssthresh; 149 if (summary->nr_nacks == 0) 150 goto resume_normality; 151 } 152 goto out; 153 154 default: 155 BUG(); 156 goto out; 157 } 158 159 resume_normality: 160 change = rxrpc_cong_cleared_nacks; 161 call->cong_dup_acks = 0; 162 call->cong_extra = 0; 163 call->cong_tstamp = skb->tstamp; 164 if (cwnd < call->cong_ssthresh) 165 call->cong_mode = RXRPC_CALL_SLOW_START; 166 else 167 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; 168 out: 169 cumulative_acks = 0; 170 out_no_clear_ca: 171 if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1) 172 cwnd = RXRPC_RXTX_BUFF_SIZE - 1; 173 call->cong_cwnd = cwnd; 174 call->cong_cumul_acks = cumulative_acks; 175 trace_rxrpc_congest(call, summary, acked_serial, change); 176 if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events)) 177 rxrpc_queue_call(call); 178 return; 179 180 packet_loss_detected: 181 change = rxrpc_cong_saw_nack; 182 call->cong_mode = RXRPC_CALL_PACKET_LOSS; 183 call->cong_dup_acks = 0; 184 goto send_extra_data; 185 186 send_extra_data: 187 /* Send some previously unsent DATA if we have some to advance the ACK 188 * state. 189 */ 190 if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] & 191 RXRPC_TX_ANNO_LAST || 192 summary->nr_acks != call->tx_top - call->tx_hard_ack) { 193 call->cong_extra++; 194 wake_up(&call->waitq); 195 } 196 goto out_no_clear_ca; 197 } 198 199 /* 200 * Ping the other end to fill our RTT cache and to retrieve the rwind 201 * and MTU parameters. 202 */ 203 static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb, 204 int skew) 205 { 206 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 207 ktime_t now = skb->tstamp; 208 209 if (call->peer->rtt_usage < 3 || 210 ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now)) 211 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial, 212 true, true, 213 rxrpc_propose_ack_ping_for_params); 214 } 215 216 /* 217 * Apply a hard ACK by advancing the Tx window. 218 */ 219 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to, 220 struct rxrpc_ack_summary *summary) 221 { 222 struct sk_buff *skb, *list = NULL; 223 int ix; 224 u8 annotation; 225 226 if (call->acks_lowest_nak == call->tx_hard_ack) { 227 call->acks_lowest_nak = to; 228 } else if (before_eq(call->acks_lowest_nak, to)) { 229 summary->new_low_nack = true; 230 call->acks_lowest_nak = to; 231 } 232 233 spin_lock(&call->lock); 234 235 while (before(call->tx_hard_ack, to)) { 236 call->tx_hard_ack++; 237 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK; 238 skb = call->rxtx_buffer[ix]; 239 annotation = call->rxtx_annotations[ix]; 240 rxrpc_see_skb(skb, rxrpc_skb_tx_rotated); 241 call->rxtx_buffer[ix] = NULL; 242 call->rxtx_annotations[ix] = 0; 243 skb->next = list; 244 list = skb; 245 246 if (annotation & RXRPC_TX_ANNO_LAST) 247 set_bit(RXRPC_CALL_TX_LAST, &call->flags); 248 if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK) 249 summary->nr_rot_new_acks++; 250 } 251 252 spin_unlock(&call->lock); 253 254 trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ? 255 rxrpc_transmit_rotate_last : 256 rxrpc_transmit_rotate)); 257 wake_up(&call->waitq); 258 259 while (list) { 260 skb = list; 261 list = skb->next; 262 skb->next = NULL; 263 rxrpc_free_skb(skb, rxrpc_skb_tx_freed); 264 } 265 } 266 267 /* 268 * End the transmission phase of a call. 269 * 270 * This occurs when we get an ACKALL packet, the first DATA packet of a reply, 271 * or a final ACK packet. 272 */ 273 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun, 274 const char *abort_why) 275 { 276 277 ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags)); 278 279 write_lock(&call->state_lock); 280 281 switch (call->state) { 282 case RXRPC_CALL_CLIENT_SEND_REQUEST: 283 case RXRPC_CALL_CLIENT_AWAIT_REPLY: 284 if (reply_begun) 285 call->state = RXRPC_CALL_CLIENT_RECV_REPLY; 286 else 287 call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY; 288 break; 289 290 case RXRPC_CALL_SERVER_AWAIT_ACK: 291 __rxrpc_call_completed(call); 292 rxrpc_notify_socket(call); 293 break; 294 295 default: 296 goto bad_state; 297 } 298 299 write_unlock(&call->state_lock); 300 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) { 301 rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, false, true, 302 rxrpc_propose_ack_client_tx_end); 303 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply); 304 } else { 305 trace_rxrpc_transmit(call, rxrpc_transmit_end); 306 } 307 _leave(" = ok"); 308 return true; 309 310 bad_state: 311 write_unlock(&call->state_lock); 312 kdebug("end_tx %s", rxrpc_call_states[call->state]); 313 rxrpc_proto_abort(abort_why, call, call->tx_top); 314 return false; 315 } 316 317 /* 318 * Begin the reply reception phase of a call. 319 */ 320 static bool rxrpc_receiving_reply(struct rxrpc_call *call) 321 { 322 struct rxrpc_ack_summary summary = { 0 }; 323 rxrpc_seq_t top = READ_ONCE(call->tx_top); 324 325 if (call->ackr_reason) { 326 spin_lock_bh(&call->lock); 327 call->ackr_reason = 0; 328 call->resend_at = call->expire_at; 329 call->ack_at = call->expire_at; 330 spin_unlock_bh(&call->lock); 331 rxrpc_set_timer(call, rxrpc_timer_init_for_reply, 332 ktime_get_real()); 333 } 334 335 if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) 336 rxrpc_rotate_tx_window(call, top, &summary); 337 if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) { 338 rxrpc_proto_abort("TXL", call, top); 339 return false; 340 } 341 if (!rxrpc_end_tx_phase(call, true, "ETD")) 342 return false; 343 call->tx_phase = false; 344 return true; 345 } 346 347 /* 348 * Scan a jumbo packet to validate its structure and to work out how many 349 * subpackets it contains. 350 * 351 * A jumbo packet is a collection of consecutive packets glued together with 352 * little headers between that indicate how to change the initial header for 353 * each subpacket. 354 * 355 * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but 356 * the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any 357 * size. 358 */ 359 static bool rxrpc_validate_jumbo(struct sk_buff *skb) 360 { 361 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 362 unsigned int offset = sizeof(struct rxrpc_wire_header); 363 unsigned int len = skb->len; 364 int nr_jumbo = 1; 365 u8 flags = sp->hdr.flags; 366 367 do { 368 nr_jumbo++; 369 if (len - offset < RXRPC_JUMBO_SUBPKTLEN) 370 goto protocol_error; 371 if (flags & RXRPC_LAST_PACKET) 372 goto protocol_error; 373 offset += RXRPC_JUMBO_DATALEN; 374 if (skb_copy_bits(skb, offset, &flags, 1) < 0) 375 goto protocol_error; 376 offset += sizeof(struct rxrpc_jumbo_header); 377 } while (flags & RXRPC_JUMBO_PACKET); 378 379 sp->nr_jumbo = nr_jumbo; 380 return true; 381 382 protocol_error: 383 return false; 384 } 385 386 /* 387 * Handle reception of a duplicate packet. 388 * 389 * We have to take care to avoid an attack here whereby we're given a series of 390 * jumbograms, each with a sequence number one before the preceding one and 391 * filled up to maximum UDP size. If they never send us the first packet in 392 * the sequence, they can cause us to have to hold on to around 2MiB of kernel 393 * space until the call times out. 394 * 395 * We limit the space usage by only accepting three duplicate jumbo packets per 396 * call. After that, we tell the other side we're no longer accepting jumbos 397 * (that information is encoded in the ACK packet). 398 */ 399 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq, 400 u8 annotation, bool *_jumbo_bad) 401 { 402 /* Discard normal packets that are duplicates. */ 403 if (annotation == 0) 404 return; 405 406 /* Skip jumbo subpackets that are duplicates. When we've had three or 407 * more partially duplicate jumbo packets, we refuse to take any more 408 * jumbos for this call. 409 */ 410 if (!*_jumbo_bad) { 411 call->nr_jumbo_bad++; 412 *_jumbo_bad = true; 413 } 414 } 415 416 /* 417 * Process a DATA packet, adding the packet to the Rx ring. 418 */ 419 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb, 420 u16 skew) 421 { 422 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 423 unsigned int offset = sizeof(struct rxrpc_wire_header); 424 unsigned int ix; 425 rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0; 426 rxrpc_seq_t seq = sp->hdr.seq, hard_ack; 427 bool immediate_ack = false, jumbo_bad = false, queued; 428 u16 len; 429 u8 ack = 0, flags, annotation = 0; 430 431 _enter("{%u,%u},{%u,%u}", 432 call->rx_hard_ack, call->rx_top, skb->len, seq); 433 434 _proto("Rx DATA %%%u { #%u f=%02x }", 435 sp->hdr.serial, seq, sp->hdr.flags); 436 437 if (call->state >= RXRPC_CALL_COMPLETE) 438 return; 439 440 /* Received data implicitly ACKs all of the request packets we sent 441 * when we're acting as a client. 442 */ 443 if ((call->state == RXRPC_CALL_CLIENT_SEND_REQUEST || 444 call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) && 445 !rxrpc_receiving_reply(call)) 446 return; 447 448 call->ackr_prev_seq = seq; 449 450 hard_ack = READ_ONCE(call->rx_hard_ack); 451 if (after(seq, hard_ack + call->rx_winsize)) { 452 ack = RXRPC_ACK_EXCEEDS_WINDOW; 453 ack_serial = serial; 454 goto ack; 455 } 456 457 flags = sp->hdr.flags; 458 if (flags & RXRPC_JUMBO_PACKET) { 459 if (call->nr_jumbo_bad > 3) { 460 ack = RXRPC_ACK_NOSPACE; 461 ack_serial = serial; 462 goto ack; 463 } 464 annotation = 1; 465 } 466 467 next_subpacket: 468 queued = false; 469 ix = seq & RXRPC_RXTX_BUFF_MASK; 470 len = skb->len; 471 if (flags & RXRPC_JUMBO_PACKET) 472 len = RXRPC_JUMBO_DATALEN; 473 474 if (flags & RXRPC_LAST_PACKET) { 475 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && 476 seq != call->rx_top) 477 return rxrpc_proto_abort("LSN", call, seq); 478 } else { 479 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && 480 after_eq(seq, call->rx_top)) 481 return rxrpc_proto_abort("LSA", call, seq); 482 } 483 484 trace_rxrpc_rx_data(call, seq, serial, flags, annotation); 485 if (before_eq(seq, hard_ack)) { 486 ack = RXRPC_ACK_DUPLICATE; 487 ack_serial = serial; 488 goto skip; 489 } 490 491 if (flags & RXRPC_REQUEST_ACK && !ack) { 492 ack = RXRPC_ACK_REQUESTED; 493 ack_serial = serial; 494 } 495 496 if (call->rxtx_buffer[ix]) { 497 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad); 498 if (ack != RXRPC_ACK_DUPLICATE) { 499 ack = RXRPC_ACK_DUPLICATE; 500 ack_serial = serial; 501 } 502 immediate_ack = true; 503 goto skip; 504 } 505 506 /* Queue the packet. We use a couple of memory barriers here as need 507 * to make sure that rx_top is perceived to be set after the buffer 508 * pointer and that the buffer pointer is set after the annotation and 509 * the skb data. 510 * 511 * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window() 512 * and also rxrpc_fill_out_ack(). 513 */ 514 rxrpc_get_skb(skb, rxrpc_skb_rx_got); 515 call->rxtx_annotations[ix] = annotation; 516 smp_wmb(); 517 call->rxtx_buffer[ix] = skb; 518 if (after(seq, call->rx_top)) { 519 smp_store_release(&call->rx_top, seq); 520 } else if (before(seq, call->rx_top)) { 521 /* Send an immediate ACK if we fill in a hole */ 522 if (!ack) { 523 ack = RXRPC_ACK_DELAY; 524 ack_serial = serial; 525 } 526 immediate_ack = true; 527 } 528 if (flags & RXRPC_LAST_PACKET) { 529 set_bit(RXRPC_CALL_RX_LAST, &call->flags); 530 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq); 531 } else { 532 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq); 533 } 534 queued = true; 535 536 if (after_eq(seq, call->rx_expect_next)) { 537 if (after(seq, call->rx_expect_next)) { 538 _net("OOS %u > %u", seq, call->rx_expect_next); 539 ack = RXRPC_ACK_OUT_OF_SEQUENCE; 540 ack_serial = serial; 541 } 542 call->rx_expect_next = seq + 1; 543 } 544 545 skip: 546 offset += len; 547 if (flags & RXRPC_JUMBO_PACKET) { 548 if (skb_copy_bits(skb, offset, &flags, 1) < 0) 549 return rxrpc_proto_abort("XJF", call, seq); 550 offset += sizeof(struct rxrpc_jumbo_header); 551 seq++; 552 serial++; 553 annotation++; 554 if (flags & RXRPC_JUMBO_PACKET) 555 annotation |= RXRPC_RX_ANNO_JLAST; 556 if (after(seq, hard_ack + call->rx_winsize)) { 557 ack = RXRPC_ACK_EXCEEDS_WINDOW; 558 ack_serial = serial; 559 if (!jumbo_bad) { 560 call->nr_jumbo_bad++; 561 jumbo_bad = true; 562 } 563 goto ack; 564 } 565 566 _proto("Rx DATA Jumbo %%%u", serial); 567 goto next_subpacket; 568 } 569 570 if (queued && flags & RXRPC_LAST_PACKET && !ack) { 571 ack = RXRPC_ACK_DELAY; 572 ack_serial = serial; 573 } 574 575 ack: 576 if (ack) 577 rxrpc_propose_ACK(call, ack, skew, ack_serial, 578 immediate_ack, true, 579 rxrpc_propose_ack_input_data); 580 581 if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1) 582 rxrpc_notify_socket(call); 583 _leave(" [queued]"); 584 } 585 586 /* 587 * Process a requested ACK. 588 */ 589 static void rxrpc_input_requested_ack(struct rxrpc_call *call, 590 ktime_t resp_time, 591 rxrpc_serial_t orig_serial, 592 rxrpc_serial_t ack_serial) 593 { 594 struct rxrpc_skb_priv *sp; 595 struct sk_buff *skb; 596 ktime_t sent_at; 597 int ix; 598 599 for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) { 600 skb = call->rxtx_buffer[ix]; 601 if (!skb) 602 continue; 603 604 sp = rxrpc_skb(skb); 605 if (sp->hdr.serial != orig_serial) 606 continue; 607 smp_rmb(); 608 sent_at = skb->tstamp; 609 goto found; 610 } 611 return; 612 613 found: 614 rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack, 615 orig_serial, ack_serial, sent_at, resp_time); 616 } 617 618 /* 619 * Process a ping response. 620 */ 621 static void rxrpc_input_ping_response(struct rxrpc_call *call, 622 ktime_t resp_time, 623 rxrpc_serial_t orig_serial, 624 rxrpc_serial_t ack_serial) 625 { 626 rxrpc_serial_t ping_serial; 627 ktime_t ping_time; 628 629 ping_time = call->ping_time; 630 smp_rmb(); 631 ping_serial = call->ping_serial; 632 633 if (!test_bit(RXRPC_CALL_PINGING, &call->flags) || 634 before(orig_serial, ping_serial)) 635 return; 636 clear_bit(RXRPC_CALL_PINGING, &call->flags); 637 if (after(orig_serial, ping_serial)) 638 return; 639 640 rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response, 641 orig_serial, ack_serial, ping_time, resp_time); 642 } 643 644 /* 645 * Process the extra information that may be appended to an ACK packet 646 */ 647 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb, 648 struct rxrpc_ackinfo *ackinfo) 649 { 650 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 651 struct rxrpc_peer *peer; 652 unsigned int mtu; 653 u32 rwind = ntohl(ackinfo->rwind); 654 655 _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }", 656 sp->hdr.serial, 657 ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU), 658 rwind, ntohl(ackinfo->jumbo_max)); 659 660 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1) 661 rwind = RXRPC_RXTX_BUFF_SIZE - 1; 662 call->tx_winsize = rwind; 663 if (call->cong_ssthresh > rwind) 664 call->cong_ssthresh = rwind; 665 666 mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU)); 667 668 peer = call->peer; 669 if (mtu < peer->maxdata) { 670 spin_lock_bh(&peer->lock); 671 peer->maxdata = mtu; 672 peer->mtu = mtu + peer->hdrsize; 673 spin_unlock_bh(&peer->lock); 674 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata); 675 } 676 } 677 678 /* 679 * Process individual soft ACKs. 680 * 681 * Each ACK in the array corresponds to one packet and can be either an ACK or 682 * a NAK. If we get find an explicitly NAK'd packet we resend immediately; 683 * packets that lie beyond the end of the ACK list are scheduled for resend by 684 * the timer on the basis that the peer might just not have processed them at 685 * the time the ACK was sent. 686 */ 687 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks, 688 rxrpc_seq_t seq, int nr_acks, 689 struct rxrpc_ack_summary *summary) 690 { 691 int ix; 692 u8 annotation, anno_type; 693 694 for (; nr_acks > 0; nr_acks--, seq++) { 695 ix = seq & RXRPC_RXTX_BUFF_MASK; 696 annotation = call->rxtx_annotations[ix]; 697 anno_type = annotation & RXRPC_TX_ANNO_MASK; 698 annotation &= ~RXRPC_TX_ANNO_MASK; 699 switch (*acks++) { 700 case RXRPC_ACK_TYPE_ACK: 701 summary->nr_acks++; 702 if (anno_type == RXRPC_TX_ANNO_ACK) 703 continue; 704 summary->nr_new_acks++; 705 call->rxtx_annotations[ix] = 706 RXRPC_TX_ANNO_ACK | annotation; 707 break; 708 case RXRPC_ACK_TYPE_NACK: 709 if (!summary->nr_nacks && 710 call->acks_lowest_nak != seq) { 711 call->acks_lowest_nak = seq; 712 summary->new_low_nack = true; 713 } 714 summary->nr_nacks++; 715 if (anno_type == RXRPC_TX_ANNO_NAK) 716 continue; 717 summary->nr_new_nacks++; 718 if (anno_type == RXRPC_TX_ANNO_RETRANS) 719 continue; 720 call->rxtx_annotations[ix] = 721 RXRPC_TX_ANNO_NAK | annotation; 722 break; 723 default: 724 return rxrpc_proto_abort("SFT", call, 0); 725 } 726 } 727 } 728 729 /* 730 * Process an ACK packet. 731 * 732 * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet 733 * in the ACK array. Anything before that is hard-ACK'd and may be discarded. 734 * 735 * A hard-ACK means that a packet has been processed and may be discarded; a 736 * soft-ACK means that the packet may be discarded and retransmission 737 * requested. A phase is complete when all packets are hard-ACK'd. 738 */ 739 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, 740 u16 skew) 741 { 742 struct rxrpc_ack_summary summary = { 0 }; 743 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 744 union { 745 struct rxrpc_ackpacket ack; 746 struct rxrpc_ackinfo info; 747 u8 acks[RXRPC_MAXACKS]; 748 } buf; 749 rxrpc_serial_t acked_serial; 750 rxrpc_seq_t first_soft_ack, hard_ack; 751 int nr_acks, offset, ioffset; 752 753 _enter(""); 754 755 offset = sizeof(struct rxrpc_wire_header); 756 if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) { 757 _debug("extraction failure"); 758 return rxrpc_proto_abort("XAK", call, 0); 759 } 760 offset += sizeof(buf.ack); 761 762 acked_serial = ntohl(buf.ack.serial); 763 first_soft_ack = ntohl(buf.ack.firstPacket); 764 hard_ack = first_soft_ack - 1; 765 nr_acks = buf.ack.nAcks; 766 summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ? 767 buf.ack.reason : RXRPC_ACK__INVALID); 768 769 trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial, 770 first_soft_ack, ntohl(buf.ack.previousPacket), 771 summary.ack_reason, nr_acks); 772 773 if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE) 774 rxrpc_input_ping_response(call, skb->tstamp, acked_serial, 775 sp->hdr.serial); 776 if (buf.ack.reason == RXRPC_ACK_REQUESTED) 777 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial, 778 sp->hdr.serial); 779 780 if (buf.ack.reason == RXRPC_ACK_PING) { 781 _proto("Rx ACK %%%u PING Request", sp->hdr.serial); 782 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE, 783 skew, sp->hdr.serial, true, true, 784 rxrpc_propose_ack_respond_to_ping); 785 } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) { 786 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, 787 skew, sp->hdr.serial, true, true, 788 rxrpc_propose_ack_respond_to_ack); 789 } 790 791 ioffset = offset + nr_acks + 3; 792 if (skb->len >= ioffset + sizeof(buf.info)) { 793 if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0) 794 return rxrpc_proto_abort("XAI", call, 0); 795 rxrpc_input_ackinfo(call, skb, &buf.info); 796 } 797 798 if (first_soft_ack == 0) 799 return rxrpc_proto_abort("AK0", call, 0); 800 801 /* Ignore ACKs unless we are or have just been transmitting. */ 802 switch (call->state) { 803 case RXRPC_CALL_CLIENT_SEND_REQUEST: 804 case RXRPC_CALL_CLIENT_AWAIT_REPLY: 805 case RXRPC_CALL_SERVER_SEND_REPLY: 806 case RXRPC_CALL_SERVER_AWAIT_ACK: 807 break; 808 default: 809 return; 810 } 811 812 /* Discard any out-of-order or duplicate ACKs. */ 813 if (before_eq(sp->hdr.serial, call->acks_latest)) { 814 _debug("discard ACK %d <= %d", 815 sp->hdr.serial, call->acks_latest); 816 return; 817 } 818 call->acks_latest_ts = skb->tstamp; 819 call->acks_latest = sp->hdr.serial; 820 821 if (before(hard_ack, call->tx_hard_ack) || 822 after(hard_ack, call->tx_top)) 823 return rxrpc_proto_abort("AKW", call, 0); 824 if (nr_acks > call->tx_top - hard_ack) 825 return rxrpc_proto_abort("AKN", call, 0); 826 827 if (after(hard_ack, call->tx_hard_ack)) 828 rxrpc_rotate_tx_window(call, hard_ack, &summary); 829 830 if (nr_acks > 0) { 831 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) 832 return rxrpc_proto_abort("XSA", call, 0); 833 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks, 834 &summary); 835 } 836 837 if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) { 838 rxrpc_end_tx_phase(call, false, "ETA"); 839 return; 840 } 841 842 if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] & 843 RXRPC_TX_ANNO_LAST && 844 summary.nr_acks == call->tx_top - hard_ack && 845 rxrpc_is_client_call(call)) 846 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial, 847 false, true, 848 rxrpc_propose_ack_ping_for_lost_reply); 849 850 return rxrpc_congestion_management(call, skb, &summary, acked_serial); 851 } 852 853 /* 854 * Process an ACKALL packet. 855 */ 856 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb) 857 { 858 struct rxrpc_ack_summary summary = { 0 }; 859 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 860 861 _proto("Rx ACKALL %%%u", sp->hdr.serial); 862 863 rxrpc_rotate_tx_window(call, call->tx_top, &summary); 864 if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) 865 rxrpc_end_tx_phase(call, false, "ETL"); 866 } 867 868 /* 869 * Process an ABORT packet. 870 */ 871 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb) 872 { 873 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 874 __be32 wtmp; 875 u32 abort_code = RX_CALL_DEAD; 876 877 _enter(""); 878 879 if (skb->len >= 4 && 880 skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), 881 &wtmp, sizeof(wtmp)) >= 0) 882 abort_code = ntohl(wtmp); 883 884 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code); 885 886 if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, 887 abort_code, ECONNABORTED)) 888 rxrpc_notify_socket(call); 889 } 890 891 /* 892 * Process an incoming call packet. 893 */ 894 static void rxrpc_input_call_packet(struct rxrpc_call *call, 895 struct sk_buff *skb, u16 skew) 896 { 897 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 898 899 _enter("%p,%p", call, skb); 900 901 switch (sp->hdr.type) { 902 case RXRPC_PACKET_TYPE_DATA: 903 rxrpc_input_data(call, skb, skew); 904 break; 905 906 case RXRPC_PACKET_TYPE_ACK: 907 rxrpc_input_ack(call, skb, skew); 908 break; 909 910 case RXRPC_PACKET_TYPE_BUSY: 911 _proto("Rx BUSY %%%u", sp->hdr.serial); 912 913 /* Just ignore BUSY packets from the server; the retry and 914 * lifespan timers will take care of business. BUSY packets 915 * from the client don't make sense. 916 */ 917 break; 918 919 case RXRPC_PACKET_TYPE_ABORT: 920 rxrpc_input_abort(call, skb); 921 break; 922 923 case RXRPC_PACKET_TYPE_ACKALL: 924 rxrpc_input_ackall(call, skb); 925 break; 926 927 default: 928 break; 929 } 930 931 _leave(""); 932 } 933 934 /* 935 * Handle a new call on a channel implicitly completing the preceding call on 936 * that channel. 937 * 938 * TODO: If callNumber > call_id + 1, renegotiate security. 939 */ 940 static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn, 941 struct rxrpc_call *call) 942 { 943 switch (call->state) { 944 case RXRPC_CALL_SERVER_AWAIT_ACK: 945 rxrpc_call_completed(call); 946 break; 947 case RXRPC_CALL_COMPLETE: 948 break; 949 default: 950 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, ESHUTDOWN)) { 951 set_bit(RXRPC_CALL_EV_ABORT, &call->events); 952 rxrpc_queue_call(call); 953 } 954 break; 955 } 956 957 trace_rxrpc_improper_term(call); 958 __rxrpc_disconnect_call(conn, call); 959 rxrpc_notify_socket(call); 960 } 961 962 /* 963 * post connection-level events to the connection 964 * - this includes challenges, responses, some aborts and call terminal packet 965 * retransmission. 966 */ 967 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn, 968 struct sk_buff *skb) 969 { 970 _enter("%p,%p", conn, skb); 971 972 skb_queue_tail(&conn->rx_queue, skb); 973 rxrpc_queue_conn(conn); 974 } 975 976 /* 977 * post endpoint-level events to the local endpoint 978 * - this includes debug and version messages 979 */ 980 static void rxrpc_post_packet_to_local(struct rxrpc_local *local, 981 struct sk_buff *skb) 982 { 983 _enter("%p,%p", local, skb); 984 985 skb_queue_tail(&local->event_queue, skb); 986 rxrpc_queue_local(local); 987 } 988 989 /* 990 * put a packet up for transport-level abort 991 */ 992 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb) 993 { 994 CHECK_SLAB_OKAY(&local->usage); 995 996 skb_queue_tail(&local->reject_queue, skb); 997 rxrpc_queue_local(local); 998 } 999 1000 /* 1001 * Extract the wire header from a packet and translate the byte order. 1002 */ 1003 static noinline 1004 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb) 1005 { 1006 struct rxrpc_wire_header whdr; 1007 1008 /* dig out the RxRPC connection details */ 1009 if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) 1010 return -EBADMSG; 1011 1012 memset(sp, 0, sizeof(*sp)); 1013 sp->hdr.epoch = ntohl(whdr.epoch); 1014 sp->hdr.cid = ntohl(whdr.cid); 1015 sp->hdr.callNumber = ntohl(whdr.callNumber); 1016 sp->hdr.seq = ntohl(whdr.seq); 1017 sp->hdr.serial = ntohl(whdr.serial); 1018 sp->hdr.flags = whdr.flags; 1019 sp->hdr.type = whdr.type; 1020 sp->hdr.userStatus = whdr.userStatus; 1021 sp->hdr.securityIndex = whdr.securityIndex; 1022 sp->hdr._rsvd = ntohs(whdr._rsvd); 1023 sp->hdr.serviceId = ntohs(whdr.serviceId); 1024 return 0; 1025 } 1026 1027 /* 1028 * handle data received on the local endpoint 1029 * - may be called in interrupt context 1030 * 1031 * The socket is locked by the caller and this prevents the socket from being 1032 * shut down and the local endpoint from going away, thus sk_user_data will not 1033 * be cleared until this function returns. 1034 */ 1035 void rxrpc_data_ready(struct sock *udp_sk) 1036 { 1037 struct rxrpc_connection *conn; 1038 struct rxrpc_channel *chan; 1039 struct rxrpc_call *call; 1040 struct rxrpc_skb_priv *sp; 1041 struct rxrpc_local *local = udp_sk->sk_user_data; 1042 struct sk_buff *skb; 1043 unsigned int channel; 1044 int ret, skew; 1045 1046 _enter("%p", udp_sk); 1047 1048 ASSERT(!irqs_disabled()); 1049 1050 skb = skb_recv_udp(udp_sk, 0, 1, &ret); 1051 if (!skb) { 1052 if (ret == -EAGAIN) 1053 return; 1054 _debug("UDP socket error %d", ret); 1055 return; 1056 } 1057 1058 rxrpc_new_skb(skb, rxrpc_skb_rx_received); 1059 1060 _net("recv skb %p", skb); 1061 1062 /* we'll probably need to checksum it (didn't call sock_recvmsg) */ 1063 if (skb_checksum_complete(skb)) { 1064 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 1065 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0); 1066 _leave(" [CSUM failed]"); 1067 return; 1068 } 1069 1070 __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0); 1071 1072 /* The UDP protocol already released all skb resources; 1073 * we are free to add our own data there. 1074 */ 1075 sp = rxrpc_skb(skb); 1076 1077 /* dig out the RxRPC connection details */ 1078 if (rxrpc_extract_header(sp, skb) < 0) 1079 goto bad_message; 1080 1081 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) { 1082 static int lose; 1083 if ((lose++ & 7) == 7) { 1084 trace_rxrpc_rx_lose(sp); 1085 rxrpc_lose_skb(skb, rxrpc_skb_rx_lost); 1086 return; 1087 } 1088 } 1089 1090 trace_rxrpc_rx_packet(sp); 1091 1092 _net("Rx RxRPC %s ep=%x call=%x:%x", 1093 sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient", 1094 sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber); 1095 1096 if (sp->hdr.type >= RXRPC_N_PACKET_TYPES || 1097 !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) { 1098 _proto("Rx Bad Packet Type %u", sp->hdr.type); 1099 goto bad_message; 1100 } 1101 1102 switch (sp->hdr.type) { 1103 case RXRPC_PACKET_TYPE_VERSION: 1104 rxrpc_post_packet_to_local(local, skb); 1105 goto out; 1106 1107 case RXRPC_PACKET_TYPE_BUSY: 1108 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) 1109 goto discard; 1110 1111 case RXRPC_PACKET_TYPE_DATA: 1112 if (sp->hdr.callNumber == 0) 1113 goto bad_message; 1114 if (sp->hdr.flags & RXRPC_JUMBO_PACKET && 1115 !rxrpc_validate_jumbo(skb)) 1116 goto bad_message; 1117 break; 1118 } 1119 1120 rcu_read_lock(); 1121 1122 conn = rxrpc_find_connection_rcu(local, skb); 1123 if (conn) { 1124 if (sp->hdr.securityIndex != conn->security_ix) 1125 goto wrong_security; 1126 1127 if (sp->hdr.callNumber == 0) { 1128 /* Connection-level packet */ 1129 _debug("CONN %p {%d}", conn, conn->debug_id); 1130 rxrpc_post_packet_to_conn(conn, skb); 1131 goto out_unlock; 1132 } 1133 1134 /* Note the serial number skew here */ 1135 skew = (int)sp->hdr.serial - (int)conn->hi_serial; 1136 if (skew >= 0) { 1137 if (skew > 0) 1138 conn->hi_serial = sp->hdr.serial; 1139 } else { 1140 skew = -skew; 1141 skew = min(skew, 65535); 1142 } 1143 1144 /* Call-bound packets are routed by connection channel. */ 1145 channel = sp->hdr.cid & RXRPC_CHANNELMASK; 1146 chan = &conn->channels[channel]; 1147 1148 /* Ignore really old calls */ 1149 if (sp->hdr.callNumber < chan->last_call) 1150 goto discard_unlock; 1151 1152 if (sp->hdr.callNumber == chan->last_call) { 1153 /* For the previous service call, if completed successfully, we 1154 * discard all further packets. 1155 */ 1156 if (rxrpc_conn_is_service(conn) && 1157 (chan->last_type == RXRPC_PACKET_TYPE_ACK || 1158 sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)) 1159 goto discard_unlock; 1160 1161 /* But otherwise we need to retransmit the final packet from 1162 * data cached in the connection record. 1163 */ 1164 rxrpc_post_packet_to_conn(conn, skb); 1165 goto out_unlock; 1166 } 1167 1168 call = rcu_dereference(chan->call); 1169 1170 if (sp->hdr.callNumber > chan->call_id) { 1171 if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) { 1172 rcu_read_unlock(); 1173 goto reject_packet; 1174 } 1175 if (call) 1176 rxrpc_input_implicit_end_call(conn, call); 1177 call = NULL; 1178 } 1179 } else { 1180 skew = 0; 1181 call = NULL; 1182 } 1183 1184 if (!call || atomic_read(&call->usage) == 0) { 1185 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) || 1186 sp->hdr.callNumber == 0 || 1187 sp->hdr.type != RXRPC_PACKET_TYPE_DATA) 1188 goto bad_message_unlock; 1189 if (sp->hdr.seq != 1) 1190 goto discard_unlock; 1191 call = rxrpc_new_incoming_call(local, conn, skb); 1192 if (!call) { 1193 rcu_read_unlock(); 1194 goto reject_packet; 1195 } 1196 rxrpc_send_ping(call, skb, skew); 1197 mutex_unlock(&call->user_mutex); 1198 } 1199 1200 rxrpc_input_call_packet(call, skb, skew); 1201 goto discard_unlock; 1202 1203 discard_unlock: 1204 rcu_read_unlock(); 1205 discard: 1206 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 1207 out: 1208 trace_rxrpc_rx_done(0, 0); 1209 return; 1210 1211 out_unlock: 1212 rcu_read_unlock(); 1213 goto out; 1214 1215 wrong_security: 1216 rcu_read_unlock(); 1217 trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, 1218 RXKADINCONSISTENCY, EBADMSG); 1219 skb->priority = RXKADINCONSISTENCY; 1220 goto post_abort; 1221 1222 bad_message_unlock: 1223 rcu_read_unlock(); 1224 bad_message: 1225 trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, 1226 RX_PROTOCOL_ERROR, EBADMSG); 1227 skb->priority = RX_PROTOCOL_ERROR; 1228 post_abort: 1229 skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT; 1230 reject_packet: 1231 trace_rxrpc_rx_done(skb->mark, skb->priority); 1232 rxrpc_reject_packet(local, skb); 1233 _leave(" [badmsg]"); 1234 } 1235