linux/net/rxrpc/output.c
David Howells bf7d620abf rxrpc: Don't request an ACK on the last DATA packet of a call's Tx phase
Don't request an ACK on the last DATA packet of a call's Tx phase as for a
client there will be a reply packet or some sort of ACK to shift phase.  If
the ACK is requested, OpenAFS sends a REQUESTED-ACK ACK with soft-ACKs in
it and doesn't follow up with a hard-ACK.

If we don't set the flag, OpenAFS will send a DELAY ACK that hard-ACKs the
reply data, thereby allowing the call to terminate cleanly.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-10-06 08:11:51 +01:00

464 lines
12 KiB
C

/* RxRPC packet transmission
*
* 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/net.h>
#include <linux/gfp.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
struct rxrpc_ack_buffer {
struct rxrpc_wire_header whdr;
struct rxrpc_ackpacket ack;
u8 acks[255];
u8 pad[3];
struct rxrpc_ackinfo ackinfo;
};
struct rxrpc_abort_buffer {
struct rxrpc_wire_header whdr;
__be32 abort_code;
};
/*
* Fill out an ACK packet.
*/
static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
struct rxrpc_ack_buffer *pkt,
rxrpc_seq_t *_hard_ack,
rxrpc_seq_t *_top,
u8 reason)
{
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top, seq;
int ix;
u32 mtu, jmax;
u8 *ackp = pkt->acks;
/* Barrier against rxrpc_input_data(). */
serial = call->ackr_serial;
hard_ack = READ_ONCE(call->rx_hard_ack);
top = smp_load_acquire(&call->rx_top);
*_hard_ack = hard_ack;
*_top = top;
pkt->ack.bufferSpace = htons(8);
pkt->ack.maxSkew = htons(call->ackr_skew);
pkt->ack.firstPacket = htonl(hard_ack + 1);
pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
pkt->ack.serial = htonl(serial);
pkt->ack.reason = reason;
pkt->ack.nAcks = top - hard_ack;
if (reason == RXRPC_ACK_PING)
pkt->whdr.flags |= RXRPC_REQUEST_ACK;
if (after(top, hard_ack)) {
seq = hard_ack + 1;
do {
ix = seq & RXRPC_RXTX_BUFF_MASK;
if (call->rxtx_buffer[ix])
*ackp++ = RXRPC_ACK_TYPE_ACK;
else
*ackp++ = RXRPC_ACK_TYPE_NACK;
seq++;
} while (before_eq(seq, top));
}
mtu = call->conn->params.peer->if_mtu;
mtu -= call->conn->params.peer->hdrsize;
jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
pkt->ackinfo.rxMTU = htonl(rxrpc_rx_mtu);
pkt->ackinfo.maxMTU = htonl(mtu);
pkt->ackinfo.rwind = htonl(call->rx_winsize);
pkt->ackinfo.jumbo_max = htonl(jmax);
*ackp++ = 0;
*ackp++ = 0;
*ackp++ = 0;
return top - hard_ack + 3;
}
/*
* Send an ACK call packet.
*/
int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping)
{
struct rxrpc_connection *conn = NULL;
struct rxrpc_ack_buffer *pkt;
struct msghdr msg;
struct kvec iov[2];
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top;
size_t len, n;
int ret;
u8 reason;
spin_lock_bh(&call->lock);
if (call->conn)
conn = rxrpc_get_connection_maybe(call->conn);
spin_unlock_bh(&call->lock);
if (!conn)
return -ECONNRESET;
pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
if (!pkt) {
rxrpc_put_connection(conn);
return -ENOMEM;
}
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->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(call->cid);
pkt->whdr.callNumber = htonl(call->call_id);
pkt->whdr.seq = 0;
pkt->whdr.type = RXRPC_PACKET_TYPE_ACK;
pkt->whdr.flags = RXRPC_SLOW_START_OK | conn->out_clientflag;
pkt->whdr.userStatus = 0;
pkt->whdr.securityIndex = call->security_ix;
pkt->whdr._rsvd = 0;
pkt->whdr.serviceId = htons(call->service_id);
spin_lock_bh(&call->lock);
if (ping) {
reason = RXRPC_ACK_PING;
} else {
reason = call->ackr_reason;
if (!call->ackr_reason) {
spin_unlock_bh(&call->lock);
ret = 0;
goto out;
}
call->ackr_reason = 0;
}
n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top, reason);
spin_unlock_bh(&call->lock);
iov[0].iov_base = pkt;
iov[0].iov_len = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
iov[1].iov_base = &pkt->ackinfo;
iov[1].iov_len = sizeof(pkt->ackinfo);
len = iov[0].iov_len + iov[1].iov_len;
serial = atomic_inc_return(&conn->serial);
pkt->whdr.serial = htonl(serial);
trace_rxrpc_tx_ack(call, serial,
ntohl(pkt->ack.firstPacket),
ntohl(pkt->ack.serial),
pkt->ack.reason, pkt->ack.nAcks);
if (ping) {
call->ping_serial = serial;
smp_wmb();
/* We need to stick a time in before we send the packet in case
* the reply gets back before kernel_sendmsg() completes - but
* asking UDP to send the packet can take a relatively long
* time, so we update the time after, on the assumption that
* the packet transmission is more likely to happen towards the
* end of the kernel_sendmsg() call.
*/
call->ping_time = ktime_get_real();
set_bit(RXRPC_CALL_PINGING, &call->flags);
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
}
ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
if (ping)
call->ping_time = ktime_get_real();
if (call->state < RXRPC_CALL_COMPLETE) {
if (ret < 0) {
if (ping)
clear_bit(RXRPC_CALL_PINGING, &call->flags);
rxrpc_propose_ACK(call, pkt->ack.reason,
ntohs(pkt->ack.maxSkew),
ntohl(pkt->ack.serial),
true, true,
rxrpc_propose_ack_retry_tx);
} else {
spin_lock_bh(&call->lock);
if (after(hard_ack, call->ackr_consumed))
call->ackr_consumed = hard_ack;
if (after(top, call->ackr_seen))
call->ackr_seen = top;
spin_unlock_bh(&call->lock);
}
}
out:
rxrpc_put_connection(conn);
kfree(pkt);
return ret;
}
/*
* Send an ABORT call packet.
*/
int rxrpc_send_abort_packet(struct rxrpc_call *call)
{
struct rxrpc_connection *conn = NULL;
struct rxrpc_abort_buffer pkt;
struct msghdr msg;
struct kvec iov[1];
rxrpc_serial_t serial;
int ret;
spin_lock_bh(&call->lock);
if (call->conn)
conn = rxrpc_get_connection_maybe(call->conn);
spin_unlock_bh(&call->lock);
if (!conn)
return -ECONNRESET;
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->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(call->cid);
pkt.whdr.callNumber = htonl(call->call_id);
pkt.whdr.seq = 0;
pkt.whdr.type = RXRPC_PACKET_TYPE_ABORT;
pkt.whdr.flags = conn->out_clientflag;
pkt.whdr.userStatus = 0;
pkt.whdr.securityIndex = call->security_ix;
pkt.whdr._rsvd = 0;
pkt.whdr.serviceId = htons(call->service_id);
pkt.abort_code = htonl(call->abort_code);
iov[0].iov_base = &pkt;
iov[0].iov_len = sizeof(pkt);
serial = atomic_inc_return(&conn->serial);
pkt.whdr.serial = htonl(serial);
ret = kernel_sendmsg(conn->params.local->socket,
&msg, iov, 1, sizeof(pkt));
rxrpc_put_connection(conn);
return ret;
}
/*
* send a packet through the transport endpoint
*/
int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
bool retrans)
{
struct rxrpc_connection *conn = call->conn;
struct rxrpc_wire_header whdr;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct msghdr msg;
struct kvec iov[2];
rxrpc_serial_t serial;
size_t len;
bool lost = false;
int ret, opt;
_enter(",{%d}", skb->len);
/* Each transmission of a Tx packet needs a new serial number */
serial = atomic_inc_return(&conn->serial);
whdr.epoch = htonl(conn->proto.epoch);
whdr.cid = htonl(call->cid);
whdr.callNumber = htonl(call->call_id);
whdr.seq = htonl(sp->hdr.seq);
whdr.serial = htonl(serial);
whdr.type = RXRPC_PACKET_TYPE_DATA;
whdr.flags = sp->hdr.flags;
whdr.userStatus = 0;
whdr.securityIndex = call->security_ix;
whdr._rsvd = htons(sp->hdr._rsvd);
whdr.serviceId = htons(call->service_id);
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = skb->head;
iov[1].iov_len = skb->len;
len = iov[0].iov_len + iov[1].iov_len;
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
/* If our RTT cache needs working on, request an ACK. Also request
* ACKs if a DATA packet appears to have been lost.
*/
if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
(retrans ||
call->cong_mode == RXRPC_CALL_SLOW_START ||
(call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
ktime_get_real())))
whdr.flags |= RXRPC_REQUEST_ACK;
if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
static int lose;
if ((lose++ & 7) == 7) {
ret = 0;
lost = true;
goto done;
}
}
_proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
if (iov[1].iov_len >= call->peer->maxdata)
goto send_fragmentable;
down_read(&conn->params.local->defrag_sem);
/* send the packet by UDP
* - returns -EMSGSIZE if UDP would have to fragment the packet
* to go out of the interface
* - in which case, we'll have processed the ICMP error
* message and update the peer record
*/
ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
up_read(&conn->params.local->defrag_sem);
if (ret == -EMSGSIZE)
goto send_fragmentable;
done:
trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
retrans, lost);
if (ret >= 0) {
ktime_t now = ktime_get_real();
skb->tstamp = now;
smp_wmb();
sp->hdr.serial = serial;
if (whdr.flags & RXRPC_REQUEST_ACK) {
call->peer->rtt_last_req = now;
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
}
}
_leave(" = %d [%u]", ret, call->peer->maxdata);
return ret;
send_fragmentable:
/* attempt to send this message with fragmentation enabled */
_debug("send fragment");
down_write(&conn->params.local->defrag_sem);
switch (conn->params.local->srx.transport.family) {
case AF_INET:
opt = IP_PMTUDISC_DONT;
ret = kernel_setsockopt(conn->params.local->socket,
SOL_IP, IP_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
if (ret == 0) {
ret = kernel_sendmsg(conn->params.local->socket, &msg,
iov, 2, len);
opt = IP_PMTUDISC_DO;
kernel_setsockopt(conn->params.local->socket, SOL_IP,
IP_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
}
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
opt = IPV6_PMTUDISC_DONT;
ret = kernel_setsockopt(conn->params.local->socket,
SOL_IPV6, IPV6_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
if (ret == 0) {
ret = kernel_sendmsg(conn->params.local->socket, &msg,
iov, 1, iov[0].iov_len);
opt = IPV6_PMTUDISC_DO;
kernel_setsockopt(conn->params.local->socket,
SOL_IPV6, IPV6_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
}
break;
#endif
}
up_write(&conn->params.local->defrag_sem);
goto done;
}
/*
* reject packets through the local endpoint
*/
void rxrpc_reject_packets(struct rxrpc_local *local)
{
struct sockaddr_rxrpc srx;
struct rxrpc_skb_priv *sp;
struct rxrpc_wire_header whdr;
struct sk_buff *skb;
struct msghdr msg;
struct kvec iov[2];
size_t size;
__be32 code;
_enter("%d", local->debug_id);
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = &code;
iov[1].iov_len = sizeof(code);
size = sizeof(whdr) + sizeof(code);
msg.msg_name = &srx.transport;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
memset(&whdr, 0, sizeof(whdr));
whdr.type = RXRPC_PACKET_TYPE_ABORT;
while ((skb = skb_dequeue(&local->reject_queue))) {
rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
sp = rxrpc_skb(skb);
if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
msg.msg_namelen = srx.transport_len;
code = htonl(skb->priority);
whdr.epoch = htonl(sp->hdr.epoch);
whdr.cid = htonl(sp->hdr.cid);
whdr.callNumber = htonl(sp->hdr.callNumber);
whdr.serviceId = htons(sp->hdr.serviceId);
whdr.flags = sp->hdr.flags;
whdr.flags ^= RXRPC_CLIENT_INITIATED;
whdr.flags &= RXRPC_CLIENT_INITIATED;
kernel_sendmsg(local->socket, &msg, iov, 2, size);
}
rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
}
_leave("");
}