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-rw-r--r--net/rxrpc/input.c1027
1 files changed, 1027 insertions, 0 deletions
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
new file mode 100644
index 0000000000..92495e73b8
--- /dev/null
+++ b/net/rxrpc/input.c
@@ -0,0 +1,1027 @@
+// 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"
+
+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 [RFC 5681].
+ */
+static void rxrpc_congestion_management(struct rxrpc_call *call,
+ struct sk_buff *skb,
+ struct rxrpc_ack_summary *summary,
+ rxrpc_serial_t acked_serial)
+{
+ enum rxrpc_congest_change change = rxrpc_cong_no_change;
+ unsigned int cumulative_acks = call->cong_cumul_acks;
+ unsigned int cwnd = call->cong_cwnd;
+ bool resend = false;
+
+ summary->flight_size =
+ (call->tx_top - call->acks_hard_ack) - summary->nr_acks;
+
+ if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
+ summary->retrans_timeo = true;
+ call->cong_ssthresh = max_t(unsigned int,
+ summary->flight_size / 2, 2);
+ cwnd = 1;
+ if (cwnd >= call->cong_ssthresh &&
+ call->cong_mode == RXRPC_CALL_SLOW_START) {
+ call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
+ call->cong_tstamp = skb->tstamp;
+ cumulative_acks = 0;
+ }
+ }
+
+ cumulative_acks += summary->nr_new_acks;
+ cumulative_acks += summary->nr_rot_new_acks;
+ if (cumulative_acks > 255)
+ cumulative_acks = 255;
+
+ summary->mode = call->cong_mode;
+ summary->cwnd = call->cong_cwnd;
+ summary->ssthresh = call->cong_ssthresh;
+ summary->cumulative_acks = cumulative_acks;
+ summary->dup_acks = call->cong_dup_acks;
+
+ switch (call->cong_mode) {
+ case RXRPC_CALL_SLOW_START:
+ if (summary->saw_nacks)
+ goto packet_loss_detected;
+ if (summary->cumulative_acks > 0)
+ cwnd += 1;
+ if (cwnd >= call->cong_ssthresh) {
+ call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
+ call->cong_tstamp = skb->tstamp;
+ }
+ goto out;
+
+ case RXRPC_CALL_CONGEST_AVOIDANCE:
+ if (summary->saw_nacks)
+ 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->peer->rtt_count == 0)
+ goto out;
+ if (ktime_before(skb->tstamp,
+ ktime_add_us(call->cong_tstamp,
+ call->peer->srtt_us >> 3)))
+ goto out_no_clear_ca;
+ change = rxrpc_cong_rtt_window_end;
+ call->cong_tstamp = skb->tstamp;
+ if (cumulative_acks >= cwnd)
+ cwnd++;
+ goto out;
+
+ case RXRPC_CALL_PACKET_LOSS:
+ if (!summary->saw_nacks)
+ goto resume_normality;
+
+ if (summary->new_low_nack) {
+ 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;
+
+ change = rxrpc_cong_begin_retransmission;
+ call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
+ call->cong_ssthresh = max_t(unsigned int,
+ summary->flight_size / 2, 2);
+ cwnd = call->cong_ssthresh + 3;
+ call->cong_extra = 0;
+ call->cong_dup_acks = 0;
+ resend = true;
+ goto out;
+
+ case RXRPC_CALL_FAST_RETRANSMIT:
+ if (!summary->new_low_nack) {
+ if (summary->nr_new_acks == 0)
+ cwnd += 1;
+ call->cong_dup_acks++;
+ if (call->cong_dup_acks == 2) {
+ change = rxrpc_cong_retransmit_again;
+ call->cong_dup_acks = 0;
+ resend = true;
+ }
+ } else {
+ change = rxrpc_cong_progress;
+ cwnd = call->cong_ssthresh;
+ if (!summary->saw_nacks)
+ goto resume_normality;
+ }
+ goto out;
+
+ default:
+ BUG();
+ goto out;
+ }
+
+resume_normality:
+ change = rxrpc_cong_cleared_nacks;
+ call->cong_dup_acks = 0;
+ call->cong_extra = 0;
+ call->cong_tstamp = skb->tstamp;
+ if (cwnd < call->cong_ssthresh)
+ call->cong_mode = RXRPC_CALL_SLOW_START;
+ else
+ call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
+out:
+ cumulative_acks = 0;
+out_no_clear_ca:
+ if (cwnd >= RXRPC_TX_MAX_WINDOW)
+ cwnd = RXRPC_TX_MAX_WINDOW;
+ call->cong_cwnd = cwnd;
+ call->cong_cumul_acks = cumulative_acks;
+ trace_rxrpc_congest(call, summary, acked_serial, change);
+ if (resend)
+ rxrpc_resend(call, skb);
+ return;
+
+packet_loss_detected:
+ change = rxrpc_cong_saw_nack;
+ call->cong_mode = RXRPC_CALL_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) ||
+ summary->nr_acks != call->tx_top - call->acks_hard_ack) {
+ 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;
+
+ if (call->cong_mode != RXRPC_CALL_SLOW_START &&
+ call->cong_mode != RXRPC_CALL_CONGEST_AVOIDANCE)
+ return;
+ if (__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_AWAIT_REPLY)
+ return;
+
+ rtt = ns_to_ktime(call->peer->srtt_us * (1000 / 8));
+ now = ktime_get_real();
+ if (!ktime_before(ktime_add(call->tx_last_sent, rtt), now))
+ return;
+
+ trace_rxrpc_reset_cwnd(call, now);
+ rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset);
+ call->tx_last_sent = now;
+ call->cong_mode = RXRPC_CALL_SLOW_START;
+ call->cong_ssthresh = max_t(unsigned int, call->cong_ssthresh,
+ call->cong_cwnd * 3 / 4);
+ call->cong_cwnd = max_t(unsigned int, call->cong_cwnd / 2, RXRPC_MIN_CWND);
+}
+
+/*
+ * 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_txbuf *txb;
+ bool rot_last = false;
+
+ list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
+ if (before_eq(txb->seq, call->acks_hard_ack))
+ continue;
+ summary->nr_rot_new_acks++;
+ if (test_bit(RXRPC_TXBUF_LAST, &txb->flags)) {
+ set_bit(RXRPC_CALL_TX_LAST, &call->flags);
+ rot_last = true;
+ }
+ if (txb->seq == to)
+ break;
+ }
+
+ if (rot_last)
+ set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags);
+
+ _enter("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last);
+
+ if (call->acks_lowest_nak == call->acks_hard_ack) {
+ call->acks_lowest_nak = to;
+ } else if (after(to, call->acks_lowest_nak)) {
+ summary->new_low_nack = true;
+ call->acks_lowest_nak = to;
+ }
+
+ smp_store_release(&call->acks_hard_ack, to);
+
+ trace_rxrpc_txqueue(call, (rot_last ?
+ rxrpc_txqueue_rotate_last :
+ rxrpc_txqueue_rotate));
+ 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));
+
+ 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 };
+ unsigned long now, timo;
+ rxrpc_seq_t top = READ_ONCE(call->tx_top);
+
+ if (call->ackr_reason) {
+ now = jiffies;
+ timo = now + MAX_JIFFY_OFFSET;
+
+ WRITE_ONCE(call->delay_ack_at, timo);
+ trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
+ }
+
+ 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 = jiffies + MAX_JIFFY_OFFSET;
+ 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;
+
+ __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)
+ rxrpc_end_rx_phase(call, sp->hdr.serial);
+}
+
+/*
+ * Process a DATA packet.
+ */
+static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
+ bool *_notify)
+{
+ 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;
+ else
+ call->ackr_nr_unacked++;
+
+ 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);
+
+ spin_lock(&call->recvmsg_queue.lock);
+ 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);
+ }
+
+ spin_unlock(&call->recvmsg_queue.lock);
+
+ 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)
+ rxrpc_send_ACK(call, ack_reason, serial,
+ rxrpc_propose_ack_input_data);
+ else
+ rxrpc_propose_delay_ACK(call, serial,
+ rxrpc_propose_ack_input_data);
+}
+
+/*
+ * 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;
+ unsigned int offset = sizeof(struct rxrpc_wire_header);
+ unsigned int len = skb->len - offset;
+ bool notify = false;
+
+ 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, &notify);
+ 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;
+ }
+
+ sp->offset = offset;
+ sp->len = len;
+ rxrpc_input_data_one(call, skb, &notify);
+ if (notify) {
+ 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);
+ unsigned long now, expect_req_by;
+
+ if (timo) {
+ now = jiffies;
+ expect_req_by = now + timo;
+ WRITE_ONCE(call->expect_req_by, expect_req_by);
+ rxrpc_reduce_call_timer(call, expect_req_by, now,
+ rxrpc_timer_set_for_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_peer_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);
+ 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);
+}
+
+/*
+ * Process the extra information that may be appended to an ACK packet
+ */
+static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
+ struct rxrpc_ackinfo *ackinfo)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxrpc_peer *peer;
+ unsigned int mtu;
+ bool wake = false;
+ u32 rwind = ntohl(ackinfo->rwind);
+
+ 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;
+ }
+
+ if (call->cong_ssthresh > rwind)
+ call->cong_ssthresh = rwind;
+
+ mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
+
+ peer = call->peer;
+ if (mtu < peer->maxdata) {
+ spin_lock(&peer->lock);
+ peer->maxdata = mtu;
+ peer->mtu = mtu + peer->hdrsize;
+ spin_unlock(&peer->lock);
+ }
+
+ if (wake)
+ wake_up(&call->waitq);
+}
+
+/*
+ * 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, u8 *acks,
+ rxrpc_seq_t seq, int nr_acks,
+ struct rxrpc_ack_summary *summary)
+{
+ unsigned int i;
+
+ for (i = 0; i < nr_acks; i++) {
+ if (acks[i] == RXRPC_ACK_TYPE_ACK) {
+ summary->nr_acks++;
+ summary->nr_new_acks++;
+ } else {
+ if (!summary->saw_nacks &&
+ call->acks_lowest_nak != seq + i) {
+ call->acks_lowest_nak = seq + i;
+ summary->new_low_nack = true;
+ }
+ summary->saw_nacks = true;
+ }
+ }
+}
+
+/*
+ * 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 first_pkt, rxrpc_seq_t prev_pkt)
+{
+ rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
+
+ if (after(first_pkt, base))
+ return true; /* The window advanced */
+
+ if (before(first_pkt, 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_eq(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_ackpacket ack;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxrpc_ackinfo info;
+ rxrpc_serial_t ack_serial, acked_serial;
+ rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
+ int nr_acks, offset, ioffset;
+
+ _enter("");
+
+ offset = sizeof(struct rxrpc_wire_header);
+ if (skb_copy_bits(skb, offset, &ack, sizeof(ack)) < 0)
+ return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack);
+ offset += sizeof(ack);
+
+ ack_serial = sp->hdr.serial;
+ acked_serial = ntohl(ack.serial);
+ first_soft_ack = ntohl(ack.firstPacket);
+ prev_pkt = ntohl(ack.previousPacket);
+ hard_ack = first_soft_ack - 1;
+ nr_acks = ack.nAcks;
+ summary.ack_reason = (ack.reason < RXRPC_ACK__INVALID ?
+ ack.reason : RXRPC_ACK__INVALID);
+
+ trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
+ first_soft_ack, prev_pkt,
+ summary.ack_reason, nr_acks);
+ rxrpc_inc_stat(call->rxnet, stat_rx_acks[ack.reason]);
+
+ if (acked_serial != 0) {
+ switch (ack.reason) {
+ case RXRPC_ACK_PING_RESPONSE:
+ rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
+ rxrpc_rtt_rx_ping_response);
+ break;
+ case RXRPC_ACK_REQUESTED:
+ rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
+ rxrpc_rtt_rx_requested_ack);
+ break;
+ default:
+ rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
+ rxrpc_rtt_rx_other_ack);
+ break;
+ }
+ }
+
+ /* 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(ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
+ first_soft_ack == 1 &&
+ 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(ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
+ first_soft_ack == 1 &&
+ prev_pkt == 0 &&
+ call->acks_hard_ack == 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, first_soft_ack, prev_pkt)) {
+ trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
+ first_soft_ack, call->acks_first_seq,
+ prev_pkt, call->acks_prev_seq);
+ goto send_response;
+ }
+
+ info.rxMTU = 0;
+ ioffset = offset + nr_acks + 3;
+ if (skb->len >= ioffset + sizeof(info) &&
+ skb_copy_bits(skb, ioffset, &info, sizeof(info)) < 0)
+ return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_info);
+
+ if (nr_acks > 0)
+ skb_condense(skb);
+
+ call->acks_latest_ts = skb->tstamp;
+ call->acks_first_seq = first_soft_ack;
+ call->acks_prev_seq = prev_pkt;
+
+ switch (ack.reason) {
+ case RXRPC_ACK_PING:
+ break;
+ default:
+ if (after(acked_serial, call->acks_highest_serial))
+ call->acks_highest_serial = acked_serial;
+ break;
+ }
+
+ /* Parse rwind and mtu sizes if provided. */
+ if (info.rxMTU)
+ rxrpc_input_ackinfo(call, skb, &info);
+
+ if (first_soft_ack == 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->acks_hard_ack) ||
+ 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->acks_hard_ack)) {
+ 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, skb->data + offset, first_soft_ack,
+ nr_acks, &summary);
+ }
+
+ if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
+ summary.nr_acks == call->tx_top - hard_ack &&
+ rxrpc_is_client_call(call))
+ rxrpc_propose_ping(call, ack_serial,
+ rxrpc_propose_ack_ping_for_lost_reply);
+
+ rxrpc_congestion_management(call, skb, &summary, acked_serial);
+
+send_response:
+ if (ack.reason == RXRPC_ACK_PING)
+ rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
+ rxrpc_propose_ack_respond_to_ping);
+ else if (sp->hdr.flags & RXRPC_REQUEST_ACK)
+ rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, 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) {
+ unsigned long now = jiffies, expect_rx_by;
+
+ expect_rx_by = now + timo;
+ WRITE_ONCE(call->expect_rx_by, expect_rx_by);
+ rxrpc_reduce_call_timer(call, expect_rx_by, now,
+ rxrpc_timer_set_for_normal);
+ }
+
+ 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, skb);
+}