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-rw-r--r--net/rxrpc/call_event.c547
1 files changed, 547 insertions, 0 deletions
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
new file mode 100644
index 0000000000..e363f21a20
--- /dev/null
+++ b/net/rxrpc/call_event.c
@@ -0,0 +1,547 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/circ_buf.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/udp.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+/*
+ * Propose a PING ACK be sent.
+ */
+void rxrpc_propose_ping(struct rxrpc_call *call, u32 serial,
+ enum rxrpc_propose_ack_trace why)
+{
+ unsigned long now = jiffies;
+ unsigned long ping_at = now + rxrpc_idle_ack_delay;
+
+ if (time_before(ping_at, call->ping_at)) {
+ WRITE_ONCE(call->ping_at, ping_at);
+ rxrpc_reduce_call_timer(call, ping_at, now,
+ rxrpc_timer_set_for_ping);
+ trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);
+ }
+}
+
+/*
+ * Propose a DELAY ACK be sent in the future.
+ */
+void rxrpc_propose_delay_ACK(struct rxrpc_call *call, rxrpc_serial_t serial,
+ enum rxrpc_propose_ack_trace why)
+{
+ unsigned long expiry = rxrpc_soft_ack_delay;
+ unsigned long now = jiffies, ack_at;
+
+ call->ackr_serial = serial;
+
+ if (rxrpc_soft_ack_delay < expiry)
+ expiry = rxrpc_soft_ack_delay;
+ if (call->peer->srtt_us != 0)
+ ack_at = usecs_to_jiffies(call->peer->srtt_us >> 3);
+ else
+ ack_at = expiry;
+
+ ack_at += READ_ONCE(call->tx_backoff);
+ ack_at += now;
+ if (time_before(ack_at, call->delay_ack_at)) {
+ WRITE_ONCE(call->delay_ack_at, ack_at);
+ rxrpc_reduce_call_timer(call, ack_at, now,
+ rxrpc_timer_set_for_ack);
+ }
+
+ trace_rxrpc_propose_ack(call, why, RXRPC_ACK_DELAY, serial);
+}
+
+/*
+ * Queue an ACK for immediate transmission.
+ */
+void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason,
+ rxrpc_serial_t serial, enum rxrpc_propose_ack_trace why)
+{
+ struct rxrpc_txbuf *txb;
+
+ if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
+ return;
+
+ rxrpc_inc_stat(call->rxnet, stat_tx_acks[ack_reason]);
+
+ txb = rxrpc_alloc_txbuf(call, RXRPC_PACKET_TYPE_ACK,
+ rcu_read_lock_held() ? GFP_ATOMIC | __GFP_NOWARN : GFP_NOFS);
+ if (!txb) {
+ kleave(" = -ENOMEM");
+ return;
+ }
+
+ txb->ack_why = why;
+ txb->wire.seq = 0;
+ txb->wire.type = RXRPC_PACKET_TYPE_ACK;
+ txb->wire.flags |= RXRPC_SLOW_START_OK;
+ txb->ack.bufferSpace = 0;
+ txb->ack.maxSkew = 0;
+ txb->ack.firstPacket = 0;
+ txb->ack.previousPacket = 0;
+ txb->ack.serial = htonl(serial);
+ txb->ack.reason = ack_reason;
+ txb->ack.nAcks = 0;
+
+ trace_rxrpc_send_ack(call, why, ack_reason, serial);
+ rxrpc_send_ack_packet(call, txb);
+ rxrpc_put_txbuf(txb, rxrpc_txbuf_put_ack_tx);
+}
+
+/*
+ * Handle congestion being detected by the retransmit timeout.
+ */
+static void rxrpc_congestion_timeout(struct rxrpc_call *call)
+{
+ set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
+}
+
+/*
+ * Perform retransmission of NAK'd and unack'd packets.
+ */
+void rxrpc_resend(struct rxrpc_call *call, struct sk_buff *ack_skb)
+{
+ struct rxrpc_ackpacket *ack = NULL;
+ struct rxrpc_txbuf *txb;
+ unsigned long resend_at;
+ rxrpc_seq_t transmitted = READ_ONCE(call->tx_transmitted);
+ ktime_t now, max_age, oldest, ack_ts;
+ bool unacked = false;
+ unsigned int i;
+ LIST_HEAD(retrans_queue);
+
+ _enter("{%d,%d}", call->acks_hard_ack, call->tx_top);
+
+ now = ktime_get_real();
+ max_age = ktime_sub_us(now, jiffies_to_usecs(call->peer->rto_j));
+ oldest = now;
+
+ if (list_empty(&call->tx_buffer))
+ goto no_resend;
+
+ if (list_empty(&call->tx_buffer))
+ goto no_further_resend;
+
+ trace_rxrpc_resend(call, ack_skb);
+ txb = list_first_entry(&call->tx_buffer, struct rxrpc_txbuf, call_link);
+
+ /* Scan the soft ACK table without dropping the lock and resend any
+ * explicitly NAK'd packets.
+ */
+ if (ack_skb) {
+ ack = (void *)ack_skb->data + sizeof(struct rxrpc_wire_header);
+
+ for (i = 0; i < ack->nAcks; i++) {
+ rxrpc_seq_t seq;
+
+ if (ack->acks[i] & 1)
+ continue;
+ seq = ntohl(ack->firstPacket) + i;
+ if (after(txb->seq, transmitted))
+ break;
+ if (after(txb->seq, seq))
+ continue; /* A new hard ACK probably came in */
+ list_for_each_entry_from(txb, &call->tx_buffer, call_link) {
+ if (txb->seq == seq)
+ goto found_txb;
+ }
+ goto no_further_resend;
+
+ found_txb:
+ if (after(ntohl(txb->wire.serial), call->acks_highest_serial))
+ continue; /* Ack point not yet reached */
+
+ rxrpc_see_txbuf(txb, rxrpc_txbuf_see_unacked);
+
+ if (list_empty(&txb->tx_link)) {
+ list_add_tail(&txb->tx_link, &retrans_queue);
+ set_bit(RXRPC_TXBUF_RESENT, &txb->flags);
+ }
+
+ trace_rxrpc_retransmit(call, txb->seq,
+ ktime_to_ns(ktime_sub(txb->last_sent,
+ max_age)));
+
+ if (list_is_last(&txb->call_link, &call->tx_buffer))
+ goto no_further_resend;
+ txb = list_next_entry(txb, call_link);
+ }
+ }
+
+ /* Fast-forward through the Tx queue to the point the peer says it has
+ * seen. Anything between the soft-ACK table and that point will get
+ * ACK'd or NACK'd in due course, so don't worry about it here; here we
+ * need to consider retransmitting anything beyond that point.
+ *
+ * Note that ACK for a packet can beat the update of tx_transmitted.
+ */
+ if (after_eq(READ_ONCE(call->acks_prev_seq), READ_ONCE(call->tx_transmitted)))
+ goto no_further_resend;
+
+ list_for_each_entry_from(txb, &call->tx_buffer, call_link) {
+ if (before_eq(txb->seq, READ_ONCE(call->acks_prev_seq)))
+ continue;
+ if (after(txb->seq, READ_ONCE(call->tx_transmitted)))
+ break; /* Not transmitted yet */
+
+ if (ack && ack->reason == RXRPC_ACK_PING_RESPONSE &&
+ before(ntohl(txb->wire.serial), ntohl(ack->serial)))
+ goto do_resend; /* Wasn't accounted for by a more recent ping. */
+
+ if (ktime_after(txb->last_sent, max_age)) {
+ if (ktime_before(txb->last_sent, oldest))
+ oldest = txb->last_sent;
+ continue;
+ }
+
+ do_resend:
+ unacked = true;
+ if (list_empty(&txb->tx_link)) {
+ list_add_tail(&txb->tx_link, &retrans_queue);
+ set_bit(RXRPC_TXBUF_RESENT, &txb->flags);
+ rxrpc_inc_stat(call->rxnet, stat_tx_data_retrans);
+ }
+ }
+
+no_further_resend:
+no_resend:
+ resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
+ resend_at += jiffies + rxrpc_get_rto_backoff(call->peer,
+ !list_empty(&retrans_queue));
+ WRITE_ONCE(call->resend_at, resend_at);
+
+ if (unacked)
+ rxrpc_congestion_timeout(call);
+
+ /* If there was nothing that needed retransmission then it's likely
+ * that an ACK got lost somewhere. Send a ping to find out instead of
+ * retransmitting data.
+ */
+ if (list_empty(&retrans_queue)) {
+ rxrpc_reduce_call_timer(call, resend_at, jiffies,
+ rxrpc_timer_set_for_resend);
+ ack_ts = ktime_sub(now, call->acks_latest_ts);
+ if (ktime_to_us(ack_ts) < (call->peer->srtt_us >> 3))
+ goto out;
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_lost_ack);
+ goto out;
+ }
+
+ /* Retransmit the queue */
+ while ((txb = list_first_entry_or_null(&retrans_queue,
+ struct rxrpc_txbuf, tx_link))) {
+ list_del_init(&txb->tx_link);
+ rxrpc_transmit_one(call, txb);
+ }
+
+out:
+ _leave("");
+}
+
+/*
+ * Start transmitting the reply to a service. This cancels the need to ACK the
+ * request if we haven't yet done so.
+ */
+static void rxrpc_begin_service_reply(struct rxrpc_call *call)
+{
+ unsigned long now = jiffies;
+
+ rxrpc_set_call_state(call, RXRPC_CALL_SERVER_SEND_REPLY);
+ WRITE_ONCE(call->delay_ack_at, now + MAX_JIFFY_OFFSET);
+ if (call->ackr_reason == RXRPC_ACK_DELAY)
+ call->ackr_reason = 0;
+ trace_rxrpc_timer(call, rxrpc_timer_init_for_send_reply, now);
+}
+
+/*
+ * Close the transmission phase. After this point there is no more data to be
+ * transmitted in the call.
+ */
+static void rxrpc_close_tx_phase(struct rxrpc_call *call)
+{
+ _debug("________awaiting reply/ACK__________");
+
+ switch (__rxrpc_call_state(call)) {
+ case RXRPC_CALL_CLIENT_SEND_REQUEST:
+ rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY);
+ break;
+ case RXRPC_CALL_SERVER_SEND_REPLY:
+ rxrpc_set_call_state(call, RXRPC_CALL_SERVER_AWAIT_ACK);
+ break;
+ default:
+ break;
+ }
+}
+
+static bool rxrpc_tx_window_has_space(struct rxrpc_call *call)
+{
+ unsigned int winsize = min_t(unsigned int, call->tx_winsize,
+ call->cong_cwnd + call->cong_extra);
+ rxrpc_seq_t window = call->acks_hard_ack, wtop = window + winsize;
+ rxrpc_seq_t tx_top = call->tx_top;
+ int space;
+
+ space = wtop - tx_top;
+ return space > 0;
+}
+
+/*
+ * Decant some if the sendmsg prepared queue into the transmission buffer.
+ */
+static void rxrpc_decant_prepared_tx(struct rxrpc_call *call)
+{
+ struct rxrpc_txbuf *txb;
+
+ if (!test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
+ if (list_empty(&call->tx_sendmsg))
+ return;
+ rxrpc_expose_client_call(call);
+ }
+
+ while ((txb = list_first_entry_or_null(&call->tx_sendmsg,
+ struct rxrpc_txbuf, call_link))) {
+ spin_lock(&call->tx_lock);
+ list_del(&txb->call_link);
+ spin_unlock(&call->tx_lock);
+
+ call->tx_top = txb->seq;
+ list_add_tail(&txb->call_link, &call->tx_buffer);
+
+ if (txb->wire.flags & RXRPC_LAST_PACKET)
+ rxrpc_close_tx_phase(call);
+
+ rxrpc_transmit_one(call, txb);
+
+ if (!rxrpc_tx_window_has_space(call))
+ break;
+ }
+}
+
+static void rxrpc_transmit_some_data(struct rxrpc_call *call)
+{
+ switch (__rxrpc_call_state(call)) {
+ case RXRPC_CALL_SERVER_ACK_REQUEST:
+ if (list_empty(&call->tx_sendmsg))
+ return;
+ rxrpc_begin_service_reply(call);
+ fallthrough;
+
+ case RXRPC_CALL_SERVER_SEND_REPLY:
+ case RXRPC_CALL_CLIENT_SEND_REQUEST:
+ if (!rxrpc_tx_window_has_space(call))
+ return;
+ if (list_empty(&call->tx_sendmsg)) {
+ rxrpc_inc_stat(call->rxnet, stat_tx_data_underflow);
+ return;
+ }
+ rxrpc_decant_prepared_tx(call);
+ break;
+ default:
+ return;
+ }
+}
+
+/*
+ * Ping the other end to fill our RTT cache and to retrieve the rwind
+ * and MTU parameters.
+ */
+static void rxrpc_send_initial_ping(struct rxrpc_call *call)
+{
+ if (call->peer->rtt_count < 3 ||
+ ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
+ ktime_get_real()))
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_params);
+}
+
+/*
+ * Handle retransmission and deferred ACK/abort generation.
+ */
+bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
+{
+ unsigned long now, next, t;
+ rxrpc_serial_t ackr_serial;
+ bool resend = false, expired = false;
+ s32 abort_code;
+
+ rxrpc_see_call(call, rxrpc_call_see_input);
+
+ //printk("\n--------------------\n");
+ _enter("{%d,%s,%lx}",
+ call->debug_id, rxrpc_call_states[__rxrpc_call_state(call)],
+ call->events);
+
+ if (__rxrpc_call_is_complete(call))
+ goto out;
+
+ /* Handle abort request locklessly, vs rxrpc_propose_abort(). */
+ abort_code = smp_load_acquire(&call->send_abort);
+ if (abort_code) {
+ rxrpc_abort_call(call, 0, call->send_abort, call->send_abort_err,
+ call->send_abort_why);
+ goto out;
+ }
+
+ if (skb && skb->mark == RXRPC_SKB_MARK_ERROR)
+ goto out;
+
+ /* If we see our async-event poke, check for timeout trippage. */
+ now = jiffies;
+ t = READ_ONCE(call->expect_rx_by);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
+ expired = true;
+ }
+
+ t = READ_ONCE(call->expect_req_by);
+ if (__rxrpc_call_state(call) == RXRPC_CALL_SERVER_RECV_REQUEST &&
+ time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
+ expired = true;
+ }
+
+ t = READ_ONCE(call->expect_term_by);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
+ expired = true;
+ }
+
+ t = READ_ONCE(call->delay_ack_at);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
+ cmpxchg(&call->delay_ack_at, t, now + MAX_JIFFY_OFFSET);
+ ackr_serial = xchg(&call->ackr_serial, 0);
+ rxrpc_send_ACK(call, RXRPC_ACK_DELAY, ackr_serial,
+ rxrpc_propose_ack_ping_for_lost_ack);
+ }
+
+ t = READ_ONCE(call->ack_lost_at);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
+ cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
+ set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
+ }
+
+ t = READ_ONCE(call->keepalive_at);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
+ cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_keepalive);
+ }
+
+ t = READ_ONCE(call->ping_at);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
+ cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_keepalive);
+ }
+
+ t = READ_ONCE(call->resend_at);
+ if (time_after_eq(now, t)) {
+ trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
+ cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
+ resend = true;
+ }
+
+ if (skb)
+ rxrpc_input_call_packet(call, skb);
+
+ rxrpc_transmit_some_data(call);
+
+ if (skb) {
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+
+ if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK)
+ rxrpc_congestion_degrade(call);
+ }
+
+ if (test_and_clear_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events))
+ rxrpc_send_initial_ping(call);
+
+ /* Process events */
+ if (expired) {
+ if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
+ (int)call->conn->hi_serial - (int)call->rx_serial > 0) {
+ trace_rxrpc_call_reset(call);
+ rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ECONNRESET,
+ rxrpc_abort_call_reset);
+ } else {
+ rxrpc_abort_call(call, 0, RX_CALL_TIMEOUT, -ETIME,
+ rxrpc_abort_call_timeout);
+ }
+ goto out;
+ }
+
+ if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_lost_ack);
+
+ if (resend && __rxrpc_call_state(call) != RXRPC_CALL_CLIENT_RECV_REPLY)
+ rxrpc_resend(call, NULL);
+
+ if (test_and_clear_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
+ rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
+ rxrpc_propose_ack_rx_idle);
+
+ if (call->ackr_nr_unacked > 2) {
+ if (call->peer->rtt_count < 3)
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_rtt);
+ else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
+ ktime_get_real()))
+ rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
+ rxrpc_propose_ack_ping_for_old_rtt);
+ else
+ rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
+ rxrpc_propose_ack_input_data);
+ }
+
+ /* Make sure the timer is restarted */
+ if (!__rxrpc_call_is_complete(call)) {
+ next = call->expect_rx_by;
+
+#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }
+
+ set(call->expect_req_by);
+ set(call->expect_term_by);
+ set(call->delay_ack_at);
+ set(call->ack_lost_at);
+ set(call->resend_at);
+ set(call->keepalive_at);
+ set(call->ping_at);
+
+ now = jiffies;
+ if (time_after_eq(now, next))
+ rxrpc_poke_call(call, rxrpc_call_poke_timer_now);
+
+ rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
+ }
+
+out:
+ if (__rxrpc_call_is_complete(call)) {
+ del_timer_sync(&call->timer);
+ if (!test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
+ rxrpc_disconnect_call(call);
+ if (call->security)
+ call->security->free_call_crypto(call);
+ }
+ if (call->acks_hard_ack != call->tx_bottom)
+ rxrpc_shrink_call_tx_buffer(call);
+ _leave("");
+ return true;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 19:50:06 +0000