linux/net/rxrpc/conn_event.c
David Howells 3136ef49a1 rxrpc: Delay terminal ACK transmission on a client call
Delay terminal ACK transmission on a client call by deferring it to the
connection processor.  This allows it to be skipped if we can send the next
call instead, the first DATA packet of which will implicitly ack this call.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-24 10:18:41 +00:00

479 lines
12 KiB
C

/* connection-level event handling
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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 <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include "ar-internal.h"
/*
* Retransmit terminal ACK or ABORT of the previous call.
*/
static void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
struct sk_buff *skb,
unsigned int channel)
{
struct rxrpc_skb_priv *sp = skb ? rxrpc_skb(skb) : NULL;
struct rxrpc_channel *chan;
struct msghdr msg;
struct kvec iov;
struct {
struct rxrpc_wire_header whdr;
union {
struct {
__be32 code;
} abort;
struct {
struct rxrpc_ackpacket ack;
u8 padding[3];
struct rxrpc_ackinfo info;
};
};
} __attribute__((packed)) pkt;
size_t len;
u32 serial, mtu, call_id;
_enter("%d", conn->debug_id);
chan = &conn->channels[channel];
/* If the last call got moved on whilst we were waiting to run, just
* ignore this packet.
*/
call_id = READ_ONCE(chan->last_call);
/* Sync with __rxrpc_disconnect_call() */
smp_rmb();
if (skb && call_id != sp->hdr.callNumber)
return;
msg.msg_name = &conn->params.peer->srx.transport;
msg.msg_namelen = conn->params.peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
pkt.whdr.epoch = htonl(conn->proto.epoch);
pkt.whdr.cid = htonl(conn->proto.cid);
pkt.whdr.callNumber = htonl(call_id);
pkt.whdr.seq = 0;
pkt.whdr.type = chan->last_type;
pkt.whdr.flags = conn->out_clientflag;
pkt.whdr.userStatus = 0;
pkt.whdr.securityIndex = conn->security_ix;
pkt.whdr._rsvd = 0;
pkt.whdr.serviceId = htons(conn->service_id);
len = sizeof(pkt.whdr);
switch (chan->last_type) {
case RXRPC_PACKET_TYPE_ABORT:
pkt.abort.code = htonl(chan->last_abort);
len += sizeof(pkt.abort);
break;
case RXRPC_PACKET_TYPE_ACK:
mtu = conn->params.peer->if_mtu;
mtu -= conn->params.peer->hdrsize;
pkt.ack.bufferSpace = 0;
pkt.ack.maxSkew = htons(skb ? skb->priority : 0);
pkt.ack.firstPacket = htonl(chan->last_seq + 1);
pkt.ack.previousPacket = htonl(chan->last_seq);
pkt.ack.serial = htonl(skb ? sp->hdr.serial : 0);
pkt.ack.reason = skb ? RXRPC_ACK_DUPLICATE : RXRPC_ACK_IDLE;
pkt.ack.nAcks = 0;
pkt.info.rxMTU = htonl(rxrpc_rx_mtu);
pkt.info.maxMTU = htonl(mtu);
pkt.info.rwind = htonl(rxrpc_rx_window_size);
pkt.info.jumbo_max = htonl(rxrpc_rx_jumbo_max);
pkt.whdr.flags |= RXRPC_SLOW_START_OK;
len += sizeof(pkt.ack) + sizeof(pkt.info);
break;
}
/* Resync with __rxrpc_disconnect_call() and check that the last call
* didn't get advanced whilst we were filling out the packets.
*/
smp_rmb();
if (READ_ONCE(chan->last_call) != call_id)
return;
iov.iov_base = &pkt;
iov.iov_len = len;
serial = atomic_inc_return(&conn->serial);
pkt.whdr.serial = htonl(serial);
switch (chan->last_type) {
case RXRPC_PACKET_TYPE_ABORT:
_proto("Tx ABORT %%%u { %d } [re]", serial, conn->local_abort);
break;
case RXRPC_PACKET_TYPE_ACK:
trace_rxrpc_tx_ack(NULL, serial, chan->last_seq, 0,
RXRPC_ACK_DUPLICATE, 0);
_proto("Tx ACK %%%u [re]", serial);
break;
}
kernel_sendmsg(conn->params.local->socket, &msg, &iov, 1, len);
_leave("");
return;
}
/*
* pass a connection-level abort onto all calls on that connection
*/
static void rxrpc_abort_calls(struct rxrpc_connection *conn,
enum rxrpc_call_completion compl,
u32 abort_code, int error)
{
struct rxrpc_call *call;
int i;
_enter("{%d},%x", conn->debug_id, abort_code);
spin_lock(&conn->channel_lock);
for (i = 0; i < RXRPC_MAXCALLS; i++) {
call = rcu_dereference_protected(
conn->channels[i].call,
lockdep_is_held(&conn->channel_lock));
if (call) {
if (compl == RXRPC_CALL_LOCALLY_ABORTED)
trace_rxrpc_abort("CON", call->cid,
call->call_id, 0,
abort_code, error);
if (rxrpc_set_call_completion(call, compl,
abort_code, error))
rxrpc_notify_socket(call);
}
}
spin_unlock(&conn->channel_lock);
_leave("");
}
/*
* generate a connection-level abort
*/
static int rxrpc_abort_connection(struct rxrpc_connection *conn,
int error, u32 abort_code)
{
struct rxrpc_wire_header whdr;
struct msghdr msg;
struct kvec iov[2];
__be32 word;
size_t len;
u32 serial;
int ret;
_enter("%d,,%u,%u", conn->debug_id, error, abort_code);
/* generate a connection-level abort */
spin_lock_bh(&conn->state_lock);
if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
spin_unlock_bh(&conn->state_lock);
_leave(" = 0 [already dead]");
return 0;
}
conn->state = RXRPC_CONN_LOCALLY_ABORTED;
spin_unlock_bh(&conn->state_lock);
rxrpc_abort_calls(conn, RXRPC_CALL_LOCALLY_ABORTED, abort_code, error);
msg.msg_name = &conn->params.peer->srx.transport;
msg.msg_namelen = conn->params.peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
whdr.epoch = htonl(conn->proto.epoch);
whdr.cid = htonl(conn->proto.cid);
whdr.callNumber = 0;
whdr.seq = 0;
whdr.type = RXRPC_PACKET_TYPE_ABORT;
whdr.flags = conn->out_clientflag;
whdr.userStatus = 0;
whdr.securityIndex = conn->security_ix;
whdr._rsvd = 0;
whdr.serviceId = htons(conn->service_id);
word = htonl(conn->local_abort);
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = &word;
iov[1].iov_len = sizeof(word);
len = iov[0].iov_len + iov[1].iov_len;
serial = atomic_inc_return(&conn->serial);
whdr.serial = htonl(serial);
_proto("Tx CONN ABORT %%%u { %d }", serial, conn->local_abort);
ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
if (ret < 0) {
_debug("sendmsg failed: %d", ret);
return -EAGAIN;
}
_leave(" = 0");
return 0;
}
/*
* mark a call as being on a now-secured channel
* - must be called with BH's disabled.
*/
static void rxrpc_call_is_secure(struct rxrpc_call *call)
{
_enter("%p", call);
if (call) {
write_lock_bh(&call->state_lock);
if (call->state == RXRPC_CALL_SERVER_SECURING) {
call->state = RXRPC_CALL_SERVER_ACCEPTING;
rxrpc_notify_socket(call);
}
write_unlock_bh(&call->state_lock);
}
}
/*
* connection-level Rx packet processor
*/
static int rxrpc_process_event(struct rxrpc_connection *conn,
struct sk_buff *skb,
u32 *_abort_code)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
__be32 wtmp;
u32 abort_code;
int loop, ret;
if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
_leave(" = -ECONNABORTED [%u]", conn->state);
return -ECONNABORTED;
}
_enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_DATA:
case RXRPC_PACKET_TYPE_ACK:
rxrpc_conn_retransmit_call(conn, skb,
sp->hdr.cid & RXRPC_CHANNELMASK);
return 0;
case RXRPC_PACKET_TYPE_BUSY:
/* Just ignore BUSY packets for now. */
return 0;
case RXRPC_PACKET_TYPE_ABORT:
if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
&wtmp, sizeof(wtmp)) < 0) {
trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
tracepoint_string("bad_abort"));
return -EPROTO;
}
abort_code = ntohl(wtmp);
_proto("Rx ABORT %%%u { ac=%d }", sp->hdr.serial, abort_code);
conn->state = RXRPC_CONN_REMOTELY_ABORTED;
rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED,
abort_code, -ECONNABORTED);
return -ECONNABORTED;
case RXRPC_PACKET_TYPE_CHALLENGE:
return conn->security->respond_to_challenge(conn, skb,
_abort_code);
case RXRPC_PACKET_TYPE_RESPONSE:
ret = conn->security->verify_response(conn, skb, _abort_code);
if (ret < 0)
return ret;
ret = conn->security->init_connection_security(conn);
if (ret < 0)
return ret;
ret = conn->security->prime_packet_security(conn);
if (ret < 0)
return ret;
spin_lock(&conn->channel_lock);
spin_lock(&conn->state_lock);
if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
conn->state = RXRPC_CONN_SERVICE;
spin_unlock(&conn->state_lock);
for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
rxrpc_call_is_secure(
rcu_dereference_protected(
conn->channels[loop].call,
lockdep_is_held(&conn->channel_lock)));
} else {
spin_unlock(&conn->state_lock);
}
spin_unlock(&conn->channel_lock);
return 0;
default:
trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
tracepoint_string("bad_conn_pkt"));
return -EPROTO;
}
}
/*
* set up security and issue a challenge
*/
static void rxrpc_secure_connection(struct rxrpc_connection *conn)
{
u32 abort_code;
int ret;
_enter("{%d}", conn->debug_id);
ASSERT(conn->security_ix != 0);
if (!conn->params.key) {
_debug("set up security");
ret = rxrpc_init_server_conn_security(conn);
switch (ret) {
case 0:
break;
case -ENOENT:
abort_code = RX_CALL_DEAD;
goto abort;
default:
abort_code = RXKADNOAUTH;
goto abort;
}
}
if (conn->security->issue_challenge(conn) < 0) {
abort_code = RX_CALL_DEAD;
ret = -ENOMEM;
goto abort;
}
_leave("");
return;
abort:
_debug("abort %d, %d", ret, abort_code);
rxrpc_abort_connection(conn, ret, abort_code);
_leave(" [aborted]");
}
/*
* Process delayed final ACKs that we haven't subsumed into a subsequent call.
*/
static void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn)
{
unsigned long j = jiffies, next_j;
unsigned int channel;
bool set;
again:
next_j = j + LONG_MAX;
set = false;
for (channel = 0; channel < RXRPC_MAXCALLS; channel++) {
struct rxrpc_channel *chan = &conn->channels[channel];
unsigned long ack_at;
if (!test_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags))
continue;
smp_rmb(); /* vs rxrpc_disconnect_client_call */
ack_at = READ_ONCE(chan->final_ack_at);
if (time_before(j, ack_at)) {
if (time_before(ack_at, next_j)) {
next_j = ack_at;
set = true;
}
continue;
}
if (test_and_clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel,
&conn->flags))
rxrpc_conn_retransmit_call(conn, NULL, channel);
}
j = jiffies;
if (time_before_eq(next_j, j))
goto again;
if (set)
rxrpc_reduce_conn_timer(conn, next_j);
}
/*
* connection-level event processor
*/
void rxrpc_process_connection(struct work_struct *work)
{
struct rxrpc_connection *conn =
container_of(work, struct rxrpc_connection, processor);
struct sk_buff *skb;
u32 abort_code = RX_PROTOCOL_ERROR;
int ret;
rxrpc_see_connection(conn);
if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
rxrpc_secure_connection(conn);
/* Process delayed ACKs whose time has come. */
if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
rxrpc_process_delayed_final_acks(conn);
/* go through the conn-level event packets, releasing the ref on this
* connection that each one has when we've finished with it */
while ((skb = skb_dequeue(&conn->rx_queue))) {
rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
ret = rxrpc_process_event(conn, skb, &abort_code);
switch (ret) {
case -EPROTO:
case -EKEYEXPIRED:
case -EKEYREJECTED:
goto protocol_error;
case -EAGAIN:
goto requeue_and_leave;
case -ECONNABORTED:
default:
rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
break;
}
}
out:
rxrpc_put_connection(conn);
_leave("");
return;
requeue_and_leave:
skb_queue_head(&conn->rx_queue, skb);
goto out;
protocol_error:
if (rxrpc_abort_connection(conn, ret, abort_code) < 0)
goto requeue_and_leave;
rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
goto out;
}