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input.c
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/* RxRPC packet reception
*
* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/errqueue.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/icmp.h>
#include <linux/gfp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/net_namespace.h>
#include "ar-internal.h"
static void rxrpc_proto_abort(const char *why,
struct rxrpc_call *call, rxrpc_seq_t seq)
{
if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
set_bit(RXRPC_CALL_EV_ABORT, &call->events);
rxrpc_queue_call(call);
}
}
/*
* 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->tx_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->nr_nacks > 0)
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->nr_nacks > 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->peer->rtt_usage == 0)
goto out;
if (ktime_before(skb->tstamp,
ktime_add_ns(call->cong_tstamp,
call->peer->rtt)))
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->nr_nacks == 0)
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->nr_nacks == 0)
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_RXTX_BUFF_SIZE - 1)
cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
call->cong_cwnd = cwnd;
call->cong_cumul_acks = cumulative_acks;
trace_rxrpc_congest(call, summary, acked_serial, change);
if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
rxrpc_queue_call(call);
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 (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
RXRPC_TX_ANNO_LAST ||
summary->nr_acks != call->tx_top - call->tx_hard_ack) {
call->cong_extra++;
wake_up(&call->waitq);
}
goto out_no_clear_ca;
}
/*
* Ping the other end to fill our RTT cache and to retrieve the rwind
* and MTU parameters.
*/
static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
int skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
ktime_t now = skb->tstamp;
if (call->peer->rtt_usage < 3 ||
ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
true, true,
rxrpc_propose_ack_ping_for_params);
}
/*
* Apply a hard ACK by advancing the Tx window.
*/
static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
struct rxrpc_ack_summary *summary)
{
struct sk_buff *skb, *list = NULL;
int ix;
u8 annotation;
if (call->acks_lowest_nak == call->tx_hard_ack) {
call->acks_lowest_nak = to;
} else if (before_eq(call->acks_lowest_nak, to)) {
summary->new_low_nack = true;
call->acks_lowest_nak = to;
}
spin_lock(&call->lock);
while (before(call->tx_hard_ack, to)) {
call->tx_hard_ack++;
ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
skb = call->rxtx_buffer[ix];
annotation = call->rxtx_annotations[ix];
rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
call->rxtx_buffer[ix] = NULL;
call->rxtx_annotations[ix] = 0;
skb->next = list;
list = skb;
if (annotation & RXRPC_TX_ANNO_LAST)
set_bit(RXRPC_CALL_TX_LAST, &call->flags);
if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
summary->nr_rot_new_acks++;
}
spin_unlock(&call->lock);
trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
rxrpc_transmit_rotate_last :
rxrpc_transmit_rotate));
wake_up(&call->waitq);
while (list) {
skb = list;
list = skb->next;
skb->next = NULL;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
}
}
/*
* 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 bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
const char *abort_why)
{
ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
write_lock(&call->state_lock);
switch (call->state) {
case RXRPC_CALL_CLIENT_SEND_REQUEST:
case RXRPC_CALL_CLIENT_AWAIT_REPLY:
if (reply_begun)
call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
else
call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
break;
case RXRPC_CALL_SERVER_AWAIT_ACK:
__rxrpc_call_completed(call);
rxrpc_notify_socket(call);
break;
default:
goto bad_state;
}
write_unlock(&call->state_lock);
if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
} else {
trace_rxrpc_transmit(call, rxrpc_transmit_end);
}
_leave(" = ok");
return true;
bad_state:
write_unlock(&call->state_lock);
kdebug("end_tx %s", rxrpc_call_states[call->state]);
rxrpc_proto_abort(abort_why, call, call->tx_top);
return false;
}
/*
* 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) {
spin_lock_bh(&call->lock);
call->ackr_reason = 0;
spin_unlock_bh(&call->lock);
now = jiffies;
timo = now + MAX_JIFFY_OFFSET;
WRITE_ONCE(call->resend_at, timo);
WRITE_ONCE(call->ack_at, timo);
trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
}
if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
rxrpc_rotate_tx_window(call, top, &summary);
if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
rxrpc_proto_abort("TXL", call, top);
return false;
}
if (!rxrpc_end_tx_phase(call, true, "ETD"))
return false;
call->tx_phase = false;
return true;
}
/*
* Scan a jumbo packet to validate its structure and to work out how many
* subpackets it contains.
*
* A jumbo packet is a collection of consecutive packets glued together with
* little headers between that indicate how to change the initial header for
* each subpacket.
*
* RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
* the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any
* size.
*/
static bool rxrpc_validate_jumbo(struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
unsigned int offset = sizeof(struct rxrpc_wire_header);
unsigned int len = skb->len;
int nr_jumbo = 1;
u8 flags = sp->hdr.flags;
do {
nr_jumbo++;
if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
goto protocol_error;
if (flags & RXRPC_LAST_PACKET)
goto protocol_error;
offset += RXRPC_JUMBO_DATALEN;
if (skb_copy_bits(skb, offset, &flags, 1) < 0)
goto protocol_error;
offset += sizeof(struct rxrpc_jumbo_header);
} while (flags & RXRPC_JUMBO_PACKET);
sp->nr_jumbo = nr_jumbo;
return true;
protocol_error:
return false;
}
/*
* Handle reception of a duplicate packet.
*
* We have to take care to avoid an attack here whereby we're given a series of
* jumbograms, each with a sequence number one before the preceding one and
* filled up to maximum UDP size. If they never send us the first packet in
* the sequence, they can cause us to have to hold on to around 2MiB of kernel
* space until the call times out.
*
* We limit the space usage by only accepting three duplicate jumbo packets per
* call. After that, we tell the other side we're no longer accepting jumbos
* (that information is encoded in the ACK packet).
*/
static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
u8 annotation, bool *_jumbo_bad)
{
/* Discard normal packets that are duplicates. */
if (annotation == 0)
return;
/* Skip jumbo subpackets that are duplicates. When we've had three or
* more partially duplicate jumbo packets, we refuse to take any more
* jumbos for this call.
*/
if (!*_jumbo_bad) {
call->nr_jumbo_bad++;
*_jumbo_bad = true;
}
}
/*
* Process a DATA packet, adding the packet to the Rx ring.
*/
static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
u16 skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
enum rxrpc_call_state state;
unsigned int offset = sizeof(struct rxrpc_wire_header);
unsigned int ix;
rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
bool immediate_ack = false, jumbo_bad = false, queued;
u16 len;
u8 ack = 0, flags, annotation = 0;
_enter("{%u,%u},{%u,%u}",
call->rx_hard_ack, call->rx_top, skb->len, seq);
_proto("Rx DATA %%%u { #%u f=%02x }",
sp->hdr.serial, seq, sp->hdr.flags);
state = READ_ONCE(call->state);
if (state >= RXRPC_CALL_COMPLETE)
return;
if (call->state == 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);
}
}
/* Received data implicitly ACKs all of the request packets we sent
* when we're acting as a client.
*/
if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
!rxrpc_receiving_reply(call))
return;
call->ackr_prev_seq = seq;
hard_ack = READ_ONCE(call->rx_hard_ack);
if (after(seq, hard_ack + call->rx_winsize)) {
ack = RXRPC_ACK_EXCEEDS_WINDOW;
ack_serial = serial;
goto ack;
}
flags = sp->hdr.flags;
if (flags & RXRPC_JUMBO_PACKET) {
if (call->nr_jumbo_bad > 3) {
ack = RXRPC_ACK_NOSPACE;
ack_serial = serial;
goto ack;
}
annotation = 1;
}
next_subpacket:
queued = false;
ix = seq & RXRPC_RXTX_BUFF_MASK;
len = skb->len;
if (flags & RXRPC_JUMBO_PACKET)
len = RXRPC_JUMBO_DATALEN;
if (flags & RXRPC_LAST_PACKET) {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
seq != call->rx_top)
return rxrpc_proto_abort("LSN", call, seq);
} else {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
after_eq(seq, call->rx_top))
return rxrpc_proto_abort("LSA", call, seq);
}
trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
if (before_eq(seq, hard_ack)) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
goto skip;
}
if (flags & RXRPC_REQUEST_ACK && !ack) {
ack = RXRPC_ACK_REQUESTED;
ack_serial = serial;
}
if (call->rxtx_buffer[ix]) {
rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
if (ack != RXRPC_ACK_DUPLICATE) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
}
immediate_ack = true;
goto skip;
}
/* Queue the packet. We use a couple of memory barriers here as need
* to make sure that rx_top is perceived to be set after the buffer
* pointer and that the buffer pointer is set after the annotation and
* the skb data.
*
* Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
* and also rxrpc_fill_out_ack().
*/
rxrpc_get_skb(skb, rxrpc_skb_rx_got);
call->rxtx_annotations[ix] = annotation;
smp_wmb();
call->rxtx_buffer[ix] = skb;
if (after(seq, call->rx_top)) {
smp_store_release(&call->rx_top, seq);
} else if (before(seq, call->rx_top)) {
/* Send an immediate ACK if we fill in a hole */
if (!ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
}
immediate_ack = true;
}
if (flags & RXRPC_LAST_PACKET) {
set_bit(RXRPC_CALL_RX_LAST, &call->flags);
trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
} else {
trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
}
queued = true;
if (after_eq(seq, call->rx_expect_next)) {
if (after(seq, call->rx_expect_next)) {
_net("OOS %u > %u", seq, call->rx_expect_next);
ack = RXRPC_ACK_OUT_OF_SEQUENCE;
ack_serial = serial;
}
call->rx_expect_next = seq + 1;
}
skip:
offset += len;
if (flags & RXRPC_JUMBO_PACKET) {
if (skb_copy_bits(skb, offset, &flags, 1) < 0)
return rxrpc_proto_abort("XJF", call, seq);
offset += sizeof(struct rxrpc_jumbo_header);
seq++;
serial++;
annotation++;
if (flags & RXRPC_JUMBO_PACKET)
annotation |= RXRPC_RX_ANNO_JLAST;
if (after(seq, hard_ack + call->rx_winsize)) {
ack = RXRPC_ACK_EXCEEDS_WINDOW;
ack_serial = serial;
if (!jumbo_bad) {
call->nr_jumbo_bad++;
jumbo_bad = true;
}
goto ack;
}
_proto("Rx DATA Jumbo %%%u", serial);
goto next_subpacket;
}
if (queued && flags & RXRPC_LAST_PACKET && !ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
}
ack:
if (ack)
rxrpc_propose_ACK(call, ack, skew, ack_serial,
immediate_ack, true,
rxrpc_propose_ack_input_data);
else
rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, skew, serial,
false, true,
rxrpc_propose_ack_input_data);
if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1) {
trace_rxrpc_notify_socket(call->debug_id, serial);
rxrpc_notify_socket(call);
}
_leave(" [queued]");
}
/*
* Process a requested ACK.
*/
static void rxrpc_input_requested_ack(struct rxrpc_call *call,
ktime_t resp_time,
rxrpc_serial_t orig_serial,
rxrpc_serial_t ack_serial)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
ktime_t sent_at;
int ix;
for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
skb = call->rxtx_buffer[ix];
if (!skb)
continue;
sent_at = skb->tstamp;
smp_rmb(); /* Read timestamp before serial. */
sp = rxrpc_skb(skb);
if (sp->hdr.serial != orig_serial)
continue;
goto found;
}
return;
found:
rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
orig_serial, ack_serial, sent_at, resp_time);
}
/*
* Process the response to a ping that we sent to find out if we lost an ACK.
*
* If we got back a ping response that indicates a lower tx_top than what we
* had at the time of the ping transmission, we adjudge all the DATA packets
* sent between the response tx_top and the ping-time tx_top to have been lost.
*/
static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
{
rxrpc_seq_t top, bottom, seq;
bool resend = false;
spin_lock_bh(&call->lock);
bottom = call->tx_hard_ack + 1;
top = call->acks_lost_top;
if (before(bottom, top)) {
for (seq = bottom; before_eq(seq, top); seq++) {
int ix = seq & RXRPC_RXTX_BUFF_MASK;
u8 annotation = call->rxtx_annotations[ix];
u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
if (anno_type != RXRPC_TX_ANNO_UNACK)
continue;
annotation &= ~RXRPC_TX_ANNO_MASK;
annotation |= RXRPC_TX_ANNO_RETRANS;
call->rxtx_annotations[ix] = annotation;
resend = true;
}
}
spin_unlock_bh(&call->lock);
if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
rxrpc_queue_call(call);
}
/*
* Process a ping response.
*/
static void rxrpc_input_ping_response(struct rxrpc_call *call,
ktime_t resp_time,
rxrpc_serial_t orig_serial,
rxrpc_serial_t ack_serial)
{
rxrpc_serial_t ping_serial;
ktime_t ping_time;
ping_time = call->ping_time;
smp_rmb();
ping_serial = call->ping_serial;
if (orig_serial == call->acks_lost_ping)
rxrpc_input_check_for_lost_ack(call);
if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
before(orig_serial, ping_serial))
return;
clear_bit(RXRPC_CALL_PINGING, &call->flags);
if (after(orig_serial, ping_serial))
return;
rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
orig_serial, ack_serial, ping_time, resp_time);
}
/*
* 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);
_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
sp->hdr.serial,
ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
rwind, ntohl(ackinfo->jumbo_max));
if (call->tx_winsize != rwind) {
if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
rwind = RXRPC_RXTX_BUFF_SIZE - 1;
if (rwind > call->tx_winsize)
wake = true;
trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
ntohl(ackinfo->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_bh(&peer->lock);
peer->maxdata = mtu;
peer->mtu = mtu + peer->hdrsize;
spin_unlock_bh(&peer->lock);
_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
}
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)
{
int ix;
u8 annotation, anno_type;
for (; nr_acks > 0; nr_acks--, seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
annotation = call->rxtx_annotations[ix];
anno_type = annotation & RXRPC_TX_ANNO_MASK;
annotation &= ~RXRPC_TX_ANNO_MASK;
switch (*acks++) {
case RXRPC_ACK_TYPE_ACK:
summary->nr_acks++;
if (anno_type == RXRPC_TX_ANNO_ACK)
continue;
summary->nr_new_acks++;
call->rxtx_annotations[ix] =
RXRPC_TX_ANNO_ACK | annotation;
break;
case RXRPC_ACK_TYPE_NACK:
if (!summary->nr_nacks &&
call->acks_lowest_nak != seq) {
call->acks_lowest_nak = seq;
summary->new_low_nack = true;
}
summary->nr_nacks++;
if (anno_type == RXRPC_TX_ANNO_NAK)
continue;
summary->nr_new_nacks++;
if (anno_type == RXRPC_TX_ANNO_RETRANS)
continue;
call->rxtx_annotations[ix] =
RXRPC_TX_ANNO_NAK | annotation;
break;
default:
return rxrpc_proto_abort("SFT", call, 0);
}
}
}
/*
* 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,
u16 skew)
{
struct rxrpc_ack_summary summary = { 0 };
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
union {
struct rxrpc_ackpacket ack;
struct rxrpc_ackinfo info;
u8 acks[RXRPC_MAXACKS];
} buf;
rxrpc_serial_t acked_serial;
rxrpc_seq_t first_soft_ack, hard_ack;
int nr_acks, offset, ioffset;
_enter("");
offset = sizeof(struct rxrpc_wire_header);
if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
_debug("extraction failure");
return rxrpc_proto_abort("XAK", call, 0);
}
offset += sizeof(buf.ack);
acked_serial = ntohl(buf.ack.serial);
first_soft_ack = ntohl(buf.ack.firstPacket);
hard_ack = first_soft_ack - 1;
nr_acks = buf.ack.nAcks;
summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
buf.ack.reason : RXRPC_ACK__INVALID);
trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
first_soft_ack, ntohl(buf.ack.previousPacket),
summary.ack_reason, nr_acks);
if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
sp->hdr.serial);
if (buf.ack.reason == RXRPC_ACK_REQUESTED)
rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
sp->hdr.serial);
if (buf.ack.reason == RXRPC_ACK_PING) {
_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
skew, sp->hdr.serial, true, true,
rxrpc_propose_ack_respond_to_ping);
} else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
skew, sp->hdr.serial, true, true,
rxrpc_propose_ack_respond_to_ack);
}
ioffset = offset + nr_acks + 3;
if (skb->len >= ioffset + sizeof(buf.info)) {
if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
return rxrpc_proto_abort("XAI", call, 0);
rxrpc_input_ackinfo(call, skb, &buf.info);
}
if (first_soft_ack == 0)
return rxrpc_proto_abort("AK0", call, 0);
/* Ignore ACKs unless we are or have just been transmitting. */
switch (READ_ONCE(call->state)) {
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:
return;
}
/* Discard any out-of-order or duplicate ACKs. */
if (before_eq(sp->hdr.serial, call->acks_latest)) {
_debug("discard ACK %d <= %d",
sp->hdr.serial, call->acks_latest);
return;
}
call->acks_latest_ts = skb->tstamp;
call->acks_latest = sp->hdr.serial;
if (before(hard_ack, call->tx_hard_ack) ||
after(hard_ack, call->tx_top))
return rxrpc_proto_abort("AKW", call, 0);
if (nr_acks > call->tx_top - hard_ack)
return rxrpc_proto_abort("AKN", call, 0);
if (after(hard_ack, call->tx_hard_ack))
rxrpc_rotate_tx_window(call, hard_ack, &summary);
if (nr_acks > 0) {
if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
return rxrpc_proto_abort("XSA", call, 0);
rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
&summary);
}
if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
rxrpc_end_tx_phase(call, false, "ETA");
return;
}
if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
RXRPC_TX_ANNO_LAST &&
summary.nr_acks == call->tx_top - hard_ack &&
rxrpc_is_client_call(call))
rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
false, true,
rxrpc_propose_ack_ping_for_lost_reply);
return rxrpc_congestion_management(call, skb, &summary, acked_serial);
}
/*
* Process an ACKALL packet.
*/
static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
{
struct rxrpc_ack_summary summary = { 0 };
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
_proto("Rx ACKALL %%%u", sp->hdr.serial);
rxrpc_rotate_tx_window(call, call->tx_top, &summary);
if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
rxrpc_end_tx_phase(call, false, "ETL");
}
/*
* 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);
__be32 wtmp;
u32 abort_code = RX_CALL_DEAD;
_enter("");
if (skb->len >= 4 &&
skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
&wtmp, sizeof(wtmp)) >= 0)
abort_code = ntohl(wtmp);
trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
abort_code, -ECONNABORTED))
rxrpc_notify_socket(call);
}
/*
* Process an incoming call packet.
*/
static void rxrpc_input_call_packet(struct rxrpc_call *call,
struct sk_buff *skb, u16 skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
unsigned long timo;
_enter("%p,%p", call, skb);
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:
rxrpc_input_data(call, skb, skew);
break;
case RXRPC_PACKET_TYPE_ACK:
rxrpc_input_ack(call, skb, skew);
break;
case RXRPC_PACKET_TYPE_BUSY:
_proto("Rx BUSY %%%u", sp->hdr.serial);
/* Just ignore BUSY packets from the server; the retry and
* lifespan timers will take care of business. BUSY packets