diff options
Diffstat (limited to 'net/rxrpc/input.c')
| -rw-r--r-- | net/rxrpc/input.c | 1299 |
1 files changed, 1299 insertions, 0 deletions
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c new file mode 100644 index 000000000000..24aceb183c2c --- /dev/null +++ b/net/rxrpc/input.c @@ -0,0 +1,1299 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Processing of received RxRPC packets + * + * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include "ar-internal.h" + +/* Override priority when generating ACKs for received DATA */ +static const u8 rxrpc_ack_priority[RXRPC_ACK__INVALID] = { + [RXRPC_ACK_IDLE] = 1, + [RXRPC_ACK_DELAY] = 2, + [RXRPC_ACK_REQUESTED] = 3, + [RXRPC_ACK_DUPLICATE] = 4, + [RXRPC_ACK_EXCEEDS_WINDOW] = 5, + [RXRPC_ACK_NOSPACE] = 6, + [RXRPC_ACK_OUT_OF_SEQUENCE] = 7, +}; + +static void rxrpc_proto_abort(struct rxrpc_call *call, rxrpc_seq_t seq, + enum rxrpc_abort_reason why) +{ + rxrpc_abort_call(call, seq, RX_PROTOCOL_ERROR, -EBADMSG, why); +} + +/* + * Do TCP-style congestion management [RFC5681]. + */ +static void rxrpc_congestion_management(struct rxrpc_call *call, + struct rxrpc_ack_summary *summary) +{ + summary->change = rxrpc_cong_no_change; + summary->in_flight = rxrpc_tx_in_flight(call); + + if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) { + summary->retrans_timeo = true; + call->cong_ssthresh = umax(summary->in_flight / 2, 2); + call->cong_cwnd = 1; + if (call->cong_cwnd >= call->cong_ssthresh && + call->cong_ca_state == RXRPC_CA_SLOW_START) { + call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE; + call->cong_tstamp = call->acks_latest_ts; + call->cong_cumul_acks = 0; + } + } + + call->cong_cumul_acks += summary->nr_new_sacks; + call->cong_cumul_acks += summary->nr_new_hacks; + if (call->cong_cumul_acks > 255) + call->cong_cumul_acks = 255; + + switch (call->cong_ca_state) { + case RXRPC_CA_SLOW_START: + if (call->acks_nr_snacks > 0) + goto packet_loss_detected; + if (call->cong_cumul_acks > 0) + call->cong_cwnd += 1; + if (call->cong_cwnd >= call->cong_ssthresh) { + call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE; + call->cong_tstamp = call->acks_latest_ts; + } + goto out; + + case RXRPC_CA_CONGEST_AVOIDANCE: + if (call->acks_nr_snacks > 0) + goto packet_loss_detected; + + /* We analyse the number of packets that get ACK'd per RTT + * period and increase the window if we managed to fill it. + */ + if (call->rtt_count == 0) + goto out; + if (ktime_before(call->acks_latest_ts, + ktime_add_us(call->cong_tstamp, + call->srtt_us >> 3))) + goto out_no_clear_ca; + summary->change = rxrpc_cong_rtt_window_end; + call->cong_tstamp = call->acks_latest_ts; + if (call->cong_cumul_acks >= call->cong_cwnd) + call->cong_cwnd++; + goto out; + + case RXRPC_CA_PACKET_LOSS: + if (call->acks_nr_snacks == 0) + goto resume_normality; + + if (summary->new_low_snack) { + summary->change = rxrpc_cong_new_low_nack; + call->cong_dup_acks = 1; + if (call->cong_extra > 1) + call->cong_extra = 1; + goto send_extra_data; + } + + call->cong_dup_acks++; + if (call->cong_dup_acks < 3) + goto send_extra_data; + + summary->change = rxrpc_cong_begin_retransmission; + call->cong_ca_state = RXRPC_CA_FAST_RETRANSMIT; + call->cong_ssthresh = umax(summary->in_flight / 2, 2); + call->cong_cwnd = call->cong_ssthresh + 3; + call->cong_extra = 0; + call->cong_dup_acks = 0; + summary->need_retransmit = true; + summary->in_fast_or_rto_recovery = true; + goto out; + + case RXRPC_CA_FAST_RETRANSMIT: + rxrpc_tlp_init(call); + summary->in_fast_or_rto_recovery = true; + if (!summary->new_low_snack) { + if (summary->nr_new_sacks == 0) + call->cong_cwnd += 1; + call->cong_dup_acks++; + if (call->cong_dup_acks == 2) { + summary->change = rxrpc_cong_retransmit_again; + call->cong_dup_acks = 0; + summary->need_retransmit = true; + } + } else { + summary->change = rxrpc_cong_progress; + call->cong_cwnd = call->cong_ssthresh; + if (call->acks_nr_snacks == 0) { + summary->exiting_fast_or_rto_recovery = true; + goto resume_normality; + } + } + goto out; + + default: + BUG(); + goto out; + } + +resume_normality: + summary->change = rxrpc_cong_cleared_nacks; + call->cong_dup_acks = 0; + call->cong_extra = 0; + call->cong_tstamp = call->acks_latest_ts; + if (call->cong_cwnd < call->cong_ssthresh) + call->cong_ca_state = RXRPC_CA_SLOW_START; + else + call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE; +out: + call->cong_cumul_acks = 0; +out_no_clear_ca: + if (call->cong_cwnd >= RXRPC_TX_MAX_WINDOW) + call->cong_cwnd = RXRPC_TX_MAX_WINDOW; + trace_rxrpc_congest(call, summary); + return; + +packet_loss_detected: + summary->change = rxrpc_cong_saw_nack; + call->cong_ca_state = RXRPC_CA_PACKET_LOSS; + call->cong_dup_acks = 0; + goto send_extra_data; + +send_extra_data: + /* Send some previously unsent DATA if we have some to advance the ACK + * state. + */ + if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) || + call->acks_nr_sacks != call->tx_top - call->tx_bottom) { + call->cong_extra++; + wake_up(&call->waitq); + } + goto out_no_clear_ca; +} + +/* + * Degrade the congestion window if we haven't transmitted a packet for >1RTT. + */ +void rxrpc_congestion_degrade(struct rxrpc_call *call) +{ + ktime_t rtt, now, time_since; + + if (call->cong_ca_state != RXRPC_CA_SLOW_START && + call->cong_ca_state != RXRPC_CA_CONGEST_AVOIDANCE) + return; + if (__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_AWAIT_REPLY) + return; + + rtt = ns_to_ktime(call->srtt_us * (NSEC_PER_USEC / 8)); + now = ktime_get_real(); + time_since = ktime_sub(now, call->tx_last_sent); + if (ktime_before(time_since, rtt)) + return; + + trace_rxrpc_reset_cwnd(call, time_since, rtt); + rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset); + call->tx_last_sent = now; + call->cong_ca_state = RXRPC_CA_SLOW_START; + call->cong_ssthresh = umax(call->cong_ssthresh, call->cong_cwnd * 3 / 4); + call->cong_cwnd = umax(call->cong_cwnd / 2, RXRPC_MIN_CWND); +} + +/* + * Add an RTT sample derived from an ACK'd DATA packet. + */ +static void rxrpc_add_data_rtt_sample(struct rxrpc_call *call, + struct rxrpc_ack_summary *summary, + struct rxrpc_txqueue *tq, + int ix) +{ + ktime_t xmit_ts = ktime_add_us(tq->xmit_ts_base, tq->segment_xmit_ts[ix]); + + rxrpc_call_add_rtt(call, rxrpc_rtt_rx_data_ack, -1, + summary->acked_serial, summary->ack_serial, + xmit_ts, call->acks_latest_ts); + __clear_bit(ix, &tq->rtt_samples); /* Prevent repeat RTT sample */ +} + +/* + * Apply a hard ACK by advancing the Tx window. + */ +static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to, + struct rxrpc_ack_summary *summary) +{ + struct rxrpc_txqueue *tq = call->tx_queue; + rxrpc_seq_t seq = call->tx_bottom + 1; + bool rot_last = false, trace = false; + + _enter("%x,%x", call->tx_bottom, to); + + trace_rxrpc_tx_rotate(call, seq, to); + trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate); + + if (call->acks_lowest_nak == call->tx_bottom) { + call->acks_lowest_nak = to; + } else if (after(to, call->acks_lowest_nak)) { + summary->new_low_snack = true; + call->acks_lowest_nak = to; + } + + /* We may have a left over fully-consumed buffer at the front that we + * couldn't drop before (rotate_and_keep below). + */ + if (seq == call->tx_qbase + RXRPC_NR_TXQUEUE) { + call->tx_qbase += RXRPC_NR_TXQUEUE; + call->tx_queue = tq->next; + trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_free); + kfree(tq); + tq = call->tx_queue; + } + + do { + unsigned int ix = seq - call->tx_qbase; + + _debug("tq=%x seq=%x i=%d f=%x", tq->qbase, seq, ix, tq->bufs[ix]->flags); + if (tq->bufs[ix]->flags & RXRPC_LAST_PACKET) { + set_bit(RXRPC_CALL_TX_LAST, &call->flags); + rot_last = true; + } + + if (summary->acked_serial == tq->segment_serial[ix] && + test_bit(ix, &tq->rtt_samples)) + rxrpc_add_data_rtt_sample(call, summary, tq, ix); + + if (ix == tq->nr_reported_acks) { + /* Packet directly hard ACK'd. */ + tq->nr_reported_acks++; + rxrpc_input_rack_one(call, summary, tq, ix); + if (seq == call->tlp_seq) + summary->tlp_probe_acked = true; + summary->nr_new_hacks++; + __set_bit(ix, &tq->segment_acked); + trace_rxrpc_rotate(call, tq, summary, seq, rxrpc_rotate_trace_hack); + } else if (test_bit(ix, &tq->segment_acked)) { + /* Soft ACK -> hard ACK. */ + call->acks_nr_sacks--; + trace_rxrpc_rotate(call, tq, summary, seq, rxrpc_rotate_trace_sack); + } else { + /* Soft NAK -> hard ACK. */ + call->acks_nr_snacks--; + rxrpc_input_rack_one(call, summary, tq, ix); + if (seq == call->tlp_seq) + summary->tlp_probe_acked = true; + summary->nr_new_hacks++; + __set_bit(ix, &tq->segment_acked); + trace_rxrpc_rotate(call, tq, summary, seq, rxrpc_rotate_trace_snak); + } + + call->tx_nr_sent--; + if (__test_and_clear_bit(ix, &tq->segment_lost)) + call->tx_nr_lost--; + if (__test_and_clear_bit(ix, &tq->segment_retransmitted)) + call->tx_nr_resent--; + __clear_bit(ix, &tq->ever_retransmitted); + + rxrpc_put_txbuf(tq->bufs[ix], rxrpc_txbuf_put_rotated); + tq->bufs[ix] = NULL; + + WRITE_ONCE(call->tx_bottom, seq); + trace_rxrpc_txqueue(call, (rot_last ? + rxrpc_txqueue_rotate_last : + rxrpc_txqueue_rotate)); + + seq++; + trace = true; + if (!(seq & RXRPC_TXQ_MASK)) { + trace_rxrpc_rack_update(call, summary); + trace = false; + prefetch(tq->next); + if (tq != call->tx_qtail) { + call->tx_qbase += RXRPC_NR_TXQUEUE; + call->tx_queue = tq->next; + trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_free); + kfree(tq); + tq = call->tx_queue; + } else { + trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_keep); + tq = NULL; + break; + } + } + + } while (before_eq(seq, to)); + + if (trace) + trace_rxrpc_rack_update(call, summary); + + if (rot_last) { + set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags); + if (tq) { + trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_free); + kfree(tq); + call->tx_queue = NULL; + } + } + + _debug("%x,%x,%x,%d", to, call->tx_bottom, call->tx_top, rot_last); + + wake_up(&call->waitq); + return rot_last; +} + +/* + * End the transmission phase of a call. + * + * This occurs when we get an ACKALL packet, the first DATA packet of a reply, + * or a final ACK packet. + */ +static void rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun, + enum rxrpc_abort_reason abort_why) +{ + ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags)); + + call->rack_timer_mode = RXRPC_CALL_RACKTIMER_OFF; + call->rack_timo_at = KTIME_MAX; + trace_rxrpc_rack_timer(call, 0, false); + trace_rxrpc_timer_can(call, rxrpc_timer_trace_rack_off + call->rack_timer_mode); + + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_CLIENT_AWAIT_REPLY: + if (reply_begun) { + rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_RECV_REPLY); + trace_rxrpc_txqueue(call, rxrpc_txqueue_end); + break; + } + + rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY); + trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply); + break; + + case RXRPC_CALL_SERVER_AWAIT_ACK: + rxrpc_call_completed(call); + trace_rxrpc_txqueue(call, rxrpc_txqueue_end); + break; + + default: + kdebug("end_tx %s", rxrpc_call_states[__rxrpc_call_state(call)]); + rxrpc_proto_abort(call, call->tx_top, abort_why); + break; + } +} + +/* + * Begin the reply reception phase of a call. + */ +static bool rxrpc_receiving_reply(struct rxrpc_call *call) +{ + struct rxrpc_ack_summary summary = { 0 }; + rxrpc_seq_t top = READ_ONCE(call->tx_top); + + if (call->ackr_reason) { + call->delay_ack_at = KTIME_MAX; + trace_rxrpc_timer_can(call, rxrpc_timer_trace_delayed_ack); + } + + if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) { + if (!rxrpc_rotate_tx_window(call, top, &summary)) { + rxrpc_proto_abort(call, top, rxrpc_eproto_early_reply); + return false; + } + } + + rxrpc_end_tx_phase(call, true, rxrpc_eproto_unexpected_reply); + return true; +} + +/* + * End the packet reception phase. + */ +static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial) +{ + rxrpc_seq_t whigh = READ_ONCE(call->rx_highest_seq); + + _enter("%d,%s", call->debug_id, rxrpc_call_states[__rxrpc_call_state(call)]); + + trace_rxrpc_receive(call, rxrpc_receive_end, 0, whigh); + + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_RECV_REPLY: + rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_terminal_ack); + rxrpc_call_completed(call); + break; + + case RXRPC_CALL_SERVER_RECV_REQUEST: + rxrpc_set_call_state(call, RXRPC_CALL_SERVER_ACK_REQUEST); + call->expect_req_by = KTIME_MAX; + rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_processing_op); + break; + + default: + break; + } +} + +static void rxrpc_input_update_ack_window(struct rxrpc_call *call, + rxrpc_seq_t window, rxrpc_seq_t wtop) +{ + call->ackr_window = window; + call->ackr_wtop = wtop; +} + +/* + * Push a DATA packet onto the Rx queue. + */ +static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb, + rxrpc_seq_t window, rxrpc_seq_t wtop, + enum rxrpc_receive_trace why) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + bool last = sp->hdr.flags & RXRPC_LAST_PACKET; + + spin_lock_irq(&call->recvmsg_queue.lock); + + __skb_queue_tail(&call->recvmsg_queue, skb); + rxrpc_input_update_ack_window(call, window, wtop); + trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq); + if (last) + /* Change the state inside the lock so that recvmsg syncs + * correctly with it and using sendmsg() to send a reply + * doesn't race. + */ + rxrpc_end_rx_phase(call, sp->hdr.serial); + + spin_unlock_irq(&call->recvmsg_queue.lock); +} + +/* + * Process a DATA packet. + */ +static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb, + bool *_notify, rxrpc_serial_t *_ack_serial, int *_ack_reason) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + struct sk_buff *oos; + rxrpc_serial_t serial = sp->hdr.serial; + unsigned int sack = call->ackr_sack_base; + rxrpc_seq_t window = call->ackr_window; + rxrpc_seq_t wtop = call->ackr_wtop; + rxrpc_seq_t wlimit = window + call->rx_winsize - 1; + rxrpc_seq_t seq = sp->hdr.seq; + bool last = sp->hdr.flags & RXRPC_LAST_PACKET; + int ack_reason = -1; + + rxrpc_inc_stat(call->rxnet, stat_rx_data); + if (sp->hdr.flags & RXRPC_REQUEST_ACK) + rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack); + if (sp->hdr.flags & RXRPC_JUMBO_PACKET) + rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo); + + if (last) { + if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) && + seq + 1 != wtop) + return rxrpc_proto_abort(call, seq, rxrpc_eproto_different_last); + } else { + if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && + after_eq(seq, wtop)) { + pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n", + call->debug_id, seq, window, wtop, wlimit); + return rxrpc_proto_abort(call, seq, rxrpc_eproto_data_after_last); + } + } + + if (after(seq, call->rx_highest_seq)) + call->rx_highest_seq = seq; + + trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags); + + if (before(seq, window)) { + ack_reason = RXRPC_ACK_DUPLICATE; + goto send_ack; + } + if (after(seq, wlimit)) { + ack_reason = RXRPC_ACK_EXCEEDS_WINDOW; + goto send_ack; + } + + /* Queue the packet. */ + if (seq == window) { + if (sp->hdr.flags & RXRPC_REQUEST_ACK) + ack_reason = RXRPC_ACK_REQUESTED; + /* Send an immediate ACK if we fill in a hole */ + else if (!skb_queue_empty(&call->rx_oos_queue)) + ack_reason = RXRPC_ACK_DELAY; + + window++; + if (after(window, wtop)) { + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_none); + wtop = window; + } else { + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_advance); + sack = (sack + 1) % RXRPC_SACK_SIZE; + } + + + rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg); + + rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue); + *_notify = true; + + while ((oos = skb_peek(&call->rx_oos_queue))) { + struct rxrpc_skb_priv *osp = rxrpc_skb(oos); + + if (after(osp->hdr.seq, window)) + break; + + __skb_unlink(oos, &call->rx_oos_queue); + last = osp->hdr.flags & RXRPC_LAST_PACKET; + seq = osp->hdr.seq; + call->ackr_sack_table[sack] = 0; + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_fill); + sack = (sack + 1) % RXRPC_SACK_SIZE; + + window++; + rxrpc_input_queue_data(call, oos, window, wtop, + rxrpc_receive_queue_oos); + } + + call->ackr_sack_base = sack; + } else { + unsigned int slot; + + ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE; + + slot = seq - window; + sack = (sack + slot) % RXRPC_SACK_SIZE; + + if (call->ackr_sack_table[sack % RXRPC_SACK_SIZE]) { + ack_reason = RXRPC_ACK_DUPLICATE; + goto send_ack; + } + + call->ackr_sack_table[sack % RXRPC_SACK_SIZE] |= 1; + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_oos); + + if (after(seq + 1, wtop)) { + wtop = seq + 1; + rxrpc_input_update_ack_window(call, window, wtop); + } + + skb_queue_walk(&call->rx_oos_queue, oos) { + struct rxrpc_skb_priv *osp = rxrpc_skb(oos); + + if (after(osp->hdr.seq, seq)) { + rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos); + __skb_queue_before(&call->rx_oos_queue, oos, skb); + goto oos_queued; + } + } + + rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos); + __skb_queue_tail(&call->rx_oos_queue, skb); + oos_queued: + trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos, + sp->hdr.serial, sp->hdr.seq); + } + +send_ack: + if (ack_reason >= 0) { + if (rxrpc_ack_priority[ack_reason] > rxrpc_ack_priority[*_ack_reason]) { + *_ack_serial = serial; + *_ack_reason = ack_reason; + } else if (rxrpc_ack_priority[ack_reason] == rxrpc_ack_priority[*_ack_reason] && + ack_reason == RXRPC_ACK_REQUESTED) { + *_ack_serial = serial; + *_ack_reason = ack_reason; + } + } +} + +/* + * Split a jumbo packet and file the bits separately. + */ +static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_jumbo_header jhdr; + struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp; + struct sk_buff *jskb; + rxrpc_serial_t ack_serial = 0; + unsigned int offset = sizeof(struct rxrpc_wire_header); + unsigned int len = skb->len - offset; + bool notify = false; + int ack_reason = 0, count = 1, stat_ix; + + while (sp->hdr.flags & RXRPC_JUMBO_PACKET) { + if (len < RXRPC_JUMBO_SUBPKTLEN) + goto protocol_error; + if (sp->hdr.flags & RXRPC_LAST_PACKET) + goto protocol_error; + if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN, + &jhdr, sizeof(jhdr)) < 0) + goto protocol_error; + + jskb = skb_clone(skb, GFP_NOFS); + if (!jskb) { + kdebug("couldn't clone"); + return false; + } + rxrpc_new_skb(jskb, rxrpc_skb_new_jumbo_subpacket); + jsp = rxrpc_skb(jskb); + jsp->offset = offset; + jsp->len = RXRPC_JUMBO_DATALEN; + rxrpc_input_data_one(call, jskb, ¬ify, &ack_serial, &ack_reason); + rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket); + + sp->hdr.flags = jhdr.flags; + sp->hdr._rsvd = ntohs(jhdr._rsvd); + sp->hdr.seq++; + sp->hdr.serial++; + offset += RXRPC_JUMBO_SUBPKTLEN; + len -= RXRPC_JUMBO_SUBPKTLEN; + count++; + } + + sp->offset = offset; + sp->len = len; + rxrpc_input_data_one(call, skb, ¬ify, &ack_serial, &ack_reason); + + stat_ix = umin(count, ARRAY_SIZE(call->rxnet->stat_rx_jumbo)) - 1; + atomic_inc(&call->rxnet->stat_rx_jumbo[stat_ix]); + + if (ack_reason > 0) { + rxrpc_send_ACK(call, ack_reason, ack_serial, + rxrpc_propose_ack_input_data); + } else { + call->ackr_nr_unacked++; + rxrpc_propose_delay_ACK(call, sp->hdr.serial, + rxrpc_propose_ack_input_data); + } + if (notify && !test_bit(RXRPC_CALL_CONN_CHALLENGING, &call->flags)) { + trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial); + rxrpc_notify_socket(call); + } + return true; + +protocol_error: + return false; +} + +/* + * Process a DATA packet, adding the packet to the Rx ring. The caller's + * packet ref must be passed on or discarded. + */ +static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + rxrpc_serial_t serial = sp->hdr.serial; + rxrpc_seq_t seq0 = sp->hdr.seq; + + _enter("{%x,%x,%x},{%u,%x}", + call->ackr_window, call->ackr_wtop, call->rx_highest_seq, + skb->len, seq0); + + if (__rxrpc_call_is_complete(call)) + return; + + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_CLIENT_AWAIT_REPLY: + /* Received data implicitly ACKs all of the request + * packets we sent when we're acting as a client. + */ + if (!rxrpc_receiving_reply(call)) + goto out_notify; + break; + + case RXRPC_CALL_SERVER_RECV_REQUEST: { + unsigned long timo = READ_ONCE(call->next_req_timo); + + if (timo) { + ktime_t delay = ms_to_ktime(timo); + + call->expect_req_by = ktime_add(ktime_get_real(), delay); + trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_idle); + } + break; + } + + default: + break; + } + + if (!rxrpc_input_split_jumbo(call, skb)) { + rxrpc_proto_abort(call, sp->hdr.seq, rxrpc_badmsg_bad_jumbo); + goto out_notify; + } + return; + +out_notify: + trace_rxrpc_notify_socket(call->debug_id, serial); + rxrpc_notify_socket(call); + _leave(" [queued]"); +} + +/* + * See if there's a cached RTT probe to complete. + */ +static void rxrpc_complete_rtt_probe(struct rxrpc_call *call, + ktime_t resp_time, + rxrpc_serial_t acked_serial, + rxrpc_serial_t ack_serial, + enum rxrpc_rtt_rx_trace type) +{ + rxrpc_serial_t orig_serial; + unsigned long avail; + ktime_t sent_at; + bool matched = false; + int i; + + avail = READ_ONCE(call->rtt_avail); + smp_rmb(); /* Read avail bits before accessing data. */ + + for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) { + if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail)) + continue; + + sent_at = call->rtt_sent_at[i]; + orig_serial = call->rtt_serial[i]; + + if (orig_serial == acked_serial) { + clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); + smp_mb(); /* Read data before setting avail bit */ + set_bit(i, &call->rtt_avail); + rxrpc_call_add_rtt(call, type, i, acked_serial, ack_serial, + sent_at, resp_time); + matched = true; + } + + /* If a later serial is being acked, then mark this slot as + * being available. + */ + if (after(acked_serial, orig_serial)) { + trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i, + orig_serial, acked_serial, 0, 0, 0); + clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); + smp_wmb(); + set_bit(i, &call->rtt_avail); + } + } + + if (!matched) + trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0, 0); +} + +/* + * Process the extra information that may be appended to an ACK packet + */ +static void rxrpc_input_ack_trailer(struct rxrpc_call *call, struct sk_buff *skb, + struct rxrpc_acktrailer *trailer) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + struct rxrpc_peer *peer = call->peer; + unsigned int max_data, capacity; + bool wake = false; + u32 max_mtu = ntohl(trailer->maxMTU); + //u32 if_mtu = ntohl(trailer->ifMTU); + u32 rwind = ntohl(trailer->rwind); + u32 jumbo_max = ntohl(trailer->jumbo_max); + + if (rwind > RXRPC_TX_MAX_WINDOW) + rwind = RXRPC_TX_MAX_WINDOW; + if (call->tx_winsize != rwind) { + if (rwind > call->tx_winsize) + wake = true; + trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake); + call->tx_winsize = rwind; + } + + max_mtu = clamp(max_mtu, 500, 65535); + peer->ackr_max_data = max_mtu; + + if (max_mtu < peer->max_data) { + trace_rxrpc_pmtud_reduce(peer, sp->hdr.serial, max_mtu, + rxrpc_pmtud_reduce_ack); + peer->max_data = max_mtu; + } + + max_data = umin(max_mtu, peer->max_data); + capacity = max_data; + capacity += sizeof(struct rxrpc_jumbo_header); /* First subpacket has main hdr, not jumbo */ + capacity /= sizeof(struct rxrpc_jumbo_header) + RXRPC_JUMBO_DATALEN; + + if (jumbo_max == 0) { + /* The peer says it supports pmtu discovery */ + peer->ackr_adv_pmtud = true; + } else { + peer->ackr_adv_pmtud = false; + capacity = clamp(capacity, 1, jumbo_max); + } + + call->tx_jumbo_max = capacity; + + if (wake) + wake_up(&call->waitq); +} + +#if defined(CONFIG_X86) && __GNUC__ && !defined(__clang__) +/* Clang doesn't support the %z constraint modifier */ +#define shiftr_adv_rotr(shift_from, rotate_into) ({ \ + asm(" shr%z1 %1\n" \ + " inc %0\n" \ + " rcr%z2 %2\n" \ + : "+d"(shift_from), "+m"(*(shift_from)), "+rm"(rotate_into) \ + ); \ + }) +#else +#define shiftr_adv_rotr(shift_from, rotate_into) ({ \ + typeof(rotate_into) __bit0 = *(shift_from) & 1; \ + *(shift_from) >>= 1; \ + shift_from++; \ + rotate_into >>= 1; \ + rotate_into |= __bit0 << (sizeof(rotate_into) * 8 - 1); \ + }) +#endif + +/* + * Deal with RTT samples from soft ACKs. + */ +static void rxrpc_input_soft_rtt(struct rxrpc_call *call, + struct rxrpc_ack_summary *summary, + struct rxrpc_txqueue *tq) +{ + for (int ix = 0; ix < RXRPC_NR_TXQUEUE; ix++) + if (summary->acked_serial == tq->segment_serial[ix]) + return rxrpc_add_data_rtt_sample(call, summary, tq, ix); +} + +/* + * Process a batch of soft ACKs specific to a transmission queue segment. + */ +static void rxrpc_input_soft_ack_tq(struct rxrpc_call *call, + struct rxrpc_ack_summary *summary, + struct rxrpc_txqueue *tq, + unsigned long extracted_acks, + int nr_reported, + rxrpc_seq_t seq, + rxrpc_seq_t *lowest_nak) +{ + unsigned long old_reported = 0, flipped, new_acks = 0; + unsigned long a_to_n, n_to_a = 0; + int new, a, n; + + if (tq->nr_reported_acks > 0) + old_reported = ~0UL >> (RXRPC_NR_TXQUEUE - tq->nr_reported_acks); + + _enter("{%x,%lx,%d},%lx,%d,%x", + tq->qbase, tq->segment_acked, tq->nr_reported_acks, + extracted_acks, nr_reported, seq); + + _debug("[%x]", tq->qbase); + _debug("tq %16lx %u", tq->segment_acked, tq->nr_reported_acks); + _debug("sack %16lx %u", extracted_acks, nr_reported); + + /* See how many previously logged ACKs/NAKs have flipped. */ + flipped = (tq->segment_acked ^ extracted_acks) & old_reported; + if (flipped) { + n_to_a = ~tq->segment_acked & flipped; /* Old NAK -> ACK */ + a_to_n = tq->segment_acked & flipped; /* Old ACK -> NAK */ + a = hweight_long(n_to_a); + n = hweight_long(a_to_n); + _debug("flip %16lx", flipped); + _debug("ntoa %16lx %d", n_to_a, a); + _debug("aton %16lx %d", a_to_n, n); + call->acks_nr_sacks += a - n; + call->acks_nr_snacks += n - a; + summary->nr_new_sacks += a; + summary->nr_new_snacks += n; + } + + /* See how many new ACKs/NAKs have been acquired. */ + new = nr_reported - tq->nr_reported_acks; + if (new > 0) { + new_acks = extracted_acks & ~old_reported; + if (new_acks) { + a = hweight_long(new_acks); + n = new - a; + _debug("new_a %16lx new=%d a=%d n=%d", new_acks, new, a, n); + call->acks_nr_sacks += a; + call->acks_nr_snacks += n; + summary->nr_new_sacks += a; + summary->nr_new_snacks += n; + } else { + call->acks_nr_snacks += new; + summary->nr_new_snacks += new; + } + } + + tq->nr_reported_acks = nr_reported; + tq->segment_acked = extracted_acks; + trace_rxrpc_apply_acks(call, tq); + + if (extracted_acks != ~0UL) { + rxrpc_seq_t lowest = seq + ffz(extracted_acks); + + if (before(lowest, *lowest_nak)) + *lowest_nak = lowest; + } + + if (summary->acked_serial) + rxrpc_input_soft_rtt(call, summary, tq); + + new_acks |= n_to_a; + if (new_acks) + rxrpc_input_rack(call, summary, tq, new_acks); + + if (call->tlp_serial && + rxrpc_seq_in_txq(tq, call->tlp_seq) && + test_bit(call->tlp_seq - tq->qbase, &new_acks)) + summary->tlp_probe_acked = true; +} + +/* + * Process individual soft ACKs. + * + * Each ACK in the array corresponds to one packet and can be either an ACK or + * a NAK. If we get find an explicitly NAK'd packet we resend immediately; + * packets that lie beyond the end of the ACK list are scheduled for resend by + * the timer on the basis that the peer might just not have processed them at + * the time the ACK was sent. + */ +static void rxrpc_input_soft_acks(struct rxrpc_call *call, + struct rxrpc_ack_summary *summary, + struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + struct rxrpc_txqueue *tq = call->tx_queue; + unsigned long extracted = ~0UL; + unsigned int nr = 0; + rxrpc_seq_t seq = call->acks_hard_ack + 1; + rxrpc_seq_t lowest_nak = seq + sp->ack.nr_acks; + u8 *acks = skb->data + sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket); + + _enter("%x,%x,%u", tq->qbase, seq, sp->ack.nr_acks); + + while (after(seq, tq->qbase + RXRPC_NR_TXQUEUE - 1)) + tq = tq->next; + + for (unsigned int i = 0; i < sp->ack.nr_acks; i++) { + /* Decant ACKs until we hit a txqueue boundary. */ + shiftr_adv_rotr(acks, extracted); + if (i == 256) { + acks -= i; + i = 0; + } + seq++; + nr++; + if ((seq & RXRPC_TXQ_MASK) != 0) + continue; + + _debug("bound %16lx %u", extracted, nr); + + rxrpc_input_soft_ack_tq(call, summary, tq, extracted, RXRPC_NR_TXQUEUE, + seq - RXRPC_NR_TXQUEUE, &lowest_nak); + extracted = ~0UL; + nr = 0; + tq = tq->next; + prefetch(tq); + } + + if (nr) { + unsigned int nr_reported = seq & RXRPC_TXQ_MASK; + + extracted >>= RXRPC_NR_TXQUEUE - nr_reported; + _debug("tail %16lx %u", extracted, nr_reported); + rxrpc_input_soft_ack_tq(call, summary, tq, extracted, nr_reported, + seq & ~RXRPC_TXQ_MASK, &lowest_nak); + } + + /* We *can* have more nacks than we did - the peer is permitted to drop + * packets it has soft-acked and re-request them. Further, it is + * possible for the nack distribution to change whilst the number of + * nacks stays the same or goes down. + */ + if (lowest_nak != call->acks_lowest_nak) { + call->acks_lowest_nak = lowest_nak; + summary->new_low_snack = true; + } + + _debug("summary A=%d+%d N=%d+%d", + call->acks_nr_sacks, summary->nr_new_sacks, + call->acks_nr_snacks, summary->nr_new_snacks); +} + +/* + * Return true if the ACK is valid - ie. it doesn't appear to have regressed + * with respect to the ack state conveyed by preceding ACKs. + */ +static bool rxrpc_is_ack_valid(struct rxrpc_call *call, + rxrpc_seq_t hard_ack, rxrpc_seq_t prev_pkt) +{ + rxrpc_seq_t base = READ_ONCE(call->acks_hard_ack); + + if (after(hard_ack, base)) + return true; /* The window advanced */ + + if (before(hard_ack, base)) + return false; /* firstPacket regressed */ + + if (after_eq(prev_pkt, call->acks_prev_seq)) + return true; /* previousPacket hasn't regressed. */ + + /* Some rx implementations put a serial number in previousPacket. */ + if (after(prev_pkt, base + call->tx_winsize)) + return false; + return true; +} + +/* + * Process an ACK packet. + * + * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet + * in the ACK array. Anything before that is hard-ACK'd and may be discarded. + * + * A hard-ACK means that a packet has been processed and may be discarded; a + * soft-ACK means that the packet may be discarded and retransmission + * requested. A phase is complete when all packets are hard-ACK'd. + */ +static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_ack_summary summary = { 0 }; + struct rxrpc_acktrailer trailer; + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt; + int nr_acks, offset, ioffset; + + _enter(""); + + offset = sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket); + + summary.ack_serial = sp->hdr.serial; + first_soft_ack = sp->ack.first_ack; + prev_pkt = sp->ack.prev_ack; + nr_acks = sp->ack.nr_acks; + hard_ack = first_soft_ack - 1; + summary.acked_serial = sp->ack.acked_serial; + summary.ack_reason = (sp->ack.reason < RXRPC_ACK__INVALID ? + sp->ack.reason : RXRPC_ACK__INVALID); + + trace_rxrpc_rx_ack(call, sp); + rxrpc_inc_stat(call->rxnet, stat_rx_acks[summary.ack_reason]); + prefetch(call->tx_queue); + + /* If we get an EXCEEDS_WINDOW ACK from the server, it probably + * indicates that the client address changed due to NAT. The server + * lost the call because it switched to a different peer. + */ + if (unlikely(summary.ack_reason == RXRPC_ACK_EXCEEDS_WINDOW) && + hard_ack == 0 && + prev_pkt == 0 && + rxrpc_is_client_call(call)) { + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + 0, -ENETRESET); + goto send_response; + } + + /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also + * indicate a change of address. However, we can retransmit the call + * if we still have it buffered to the beginning. + */ + if (unlikely(summary.ack_reason == RXRPC_ACK_OUT_OF_SEQUENCE) && + hard_ack == 0 && + prev_pkt == 0 && + call->tx_bottom == 0 && + rxrpc_is_client_call(call)) { + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + 0, -ENETRESET); + goto send_response; + } + + /* Discard any out-of-order or duplicate ACKs (outside lock). */ + if (!rxrpc_is_ack_valid(call, hard_ack, prev_pkt)) { + trace_rxrpc_rx_discard_ack(call, summary.ack_serial, hard_ack, prev_pkt); + goto send_response; /* Still respond if requested. */ + } + + trailer.maxMTU = 0; + ioffset = offset + nr_acks + 3; + if (skb->len >= ioffset + sizeof(trailer) && + skb_copy_bits(skb, ioffset, &trailer, sizeof(trailer)) < 0) + return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_trailer); + + if (nr_acks > 0) + skb_condense(skb); + + call->acks_latest_ts = ktime_get_real(); + call->acks_hard_ack = hard_ack; + call->acks_prev_seq = prev_pkt; + + if (summary.acked_serial) { + switch (summary.ack_reason) { + case RXRPC_ACK_PING_RESPONSE: + rxrpc_complete_rtt_probe(call, call->acks_latest_ts, + summary.acked_serial, summary.ack_serial, + rxrpc_rtt_rx_ping_response); + break; + default: + if (after(summary.acked_serial, call->acks_highest_serial)) + call->acks_highest_serial = summary.acked_serial; + summary.rtt_sample_avail = true; + break; + } + } + + /* Parse rwind and mtu sizes if provided. */ + if (trailer.maxMTU) + rxrpc_input_ack_trailer(call, skb, &trailer); + + if (hard_ack + 1 == 0) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_zero); + + /* Ignore ACKs unless we are or have just been transmitting. */ + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_CLIENT_AWAIT_REPLY: + case RXRPC_CALL_SERVER_SEND_REPLY: + case RXRPC_CALL_SERVER_AWAIT_ACK: + break; + default: + goto send_response; + } + + if (before(hard_ack, call->tx_bottom) || + after(hard_ack, call->tx_top)) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_outside_window); + if (nr_acks > call->tx_top - hard_ack) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_sack_overflow); + + if (after(hard_ack, call->tx_bottom)) { + if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) { + rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack); + goto send_response; + } + } + + if (nr_acks > 0) { + if (offset > (int)skb->len - nr_acks) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_short_sack); + rxrpc_input_soft_acks(call, &summary, skb); + } + + if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) && + call->acks_nr_sacks == call->tx_top - hard_ack && + rxrpc_is_client_call(call)) + rxrpc_propose_ping(call, summary.ack_serial, + rxrpc_propose_ack_ping_for_lost_reply); + + /* Drive the congestion management algorithm first and then RACK-TLP as + * the latter depends on the state/change in state in the former. + */ + rxrpc_congestion_management(call, &summary); + rxrpc_rack_detect_loss_and_arm_timer(call, &summary); + rxrpc_tlp_process_ack(call, &summary); + if (call->tlp_serial && after_eq(summary.acked_serial, call->tlp_serial)) + call->tlp_serial = 0; + +send_response: + if (summary.ack_reason == RXRPC_ACK_PING) + rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, summary.ack_serial, + rxrpc_propose_ack_respond_to_ping); + else if (sp->hdr.flags & RXRPC_REQUEST_ACK) + rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, summary.ack_serial, + rxrpc_propose_ack_respond_to_ack); +} + +/* + * Process an ACKALL packet. + */ +static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_ack_summary summary = { 0 }; + + if (rxrpc_rotate_tx_window(call, call->tx_top, &summary)) + rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ackall); +} + +/* + * Process an ABORT packet directed at a call. + */ +static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + + trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority); + + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + skb->priority, -ECONNABORTED); +} + +/* + * Process an incoming call packet. + */ +void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + unsigned long timo; + + _enter("%p,%p", call, skb); + + if (sp->hdr.serviceId != call->dest_srx.srx_service) + call->dest_srx.srx_service = sp->hdr.serviceId; + if ((int)sp->hdr.serial - (int)call->rx_serial > 0) + call->rx_serial = sp->hdr.serial; + if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags)) + set_bit(RXRPC_CALL_RX_HEARD, &call->flags); + + timo = READ_ONCE(call->next_rx_timo); + if (timo) { + ktime_t delay = ms_to_ktime(timo); + + call->expect_rx_by = ktime_add(ktime_get_real(), delay); + trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_expect_rx); + } + + switch (sp->hdr.type) { + case RXRPC_PACKET_TYPE_DATA: + return rxrpc_input_data(call, skb); + + case RXRPC_PACKET_TYPE_ACK: + return rxrpc_input_ack(call, skb); + + case RXRPC_PACKET_TYPE_BUSY: + /* Just ignore BUSY packets from the server; the retry and + * lifespan timers will take care of business. BUSY packets + * from the client don't make sense. + */ + return; + + case RXRPC_PACKET_TYPE_ABORT: + return rxrpc_input_abort(call, skb); + + case RXRPC_PACKET_TYPE_ACKALL: + return rxrpc_input_ackall(call, skb); + + default: + break; + } +} + +/* + * Handle a new service call on a channel implicitly completing the preceding + * call on that channel. This does not apply to client conns. + * + * TODO: If callNumber > call_id + 1, renegotiate security. + */ +void rxrpc_implicit_end_call(struct rxrpc_call *call, struct sk_buff *skb) +{ + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_SERVER_AWAIT_ACK: + rxrpc_call_completed(call); + fallthrough; + case RXRPC_CALL_COMPLETE: + break; + default: + rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ESHUTDOWN, + rxrpc_eproto_improper_term); + trace_rxrpc_improper_term(call); + break; + } + + rxrpc_input_call_event(call); +} |