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linuxdebug/net/rxrpc/output.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/* RxRPC packet transmission
*
* 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/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;
};
static const char rxrpc_keepalive_string[] = "";
/*
* Increase Tx backoff on transmission failure and clear it on success.
*/
static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
{
if (ret < 0) {
u16 tx_backoff = READ_ONCE(call->tx_backoff);
if (tx_backoff < HZ)
WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
} else {
WRITE_ONCE(call->tx_backoff, 0);
}
}
/*
* Arrange for a keepalive ping a certain time after we last transmitted. This
* lets the far side know we're still interested in this call and helps keep
* the route through any intervening firewall open.
*
* Receiving a response to the ping will prevent the ->expect_rx_by timer from
* expiring.
*/
static void rxrpc_set_keepalive(struct rxrpc_call *call)
{
unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
keepalive_at += now;
WRITE_ONCE(call->keepalive_at, keepalive_at);
rxrpc_reduce_call_timer(call, keepalive_at, now,
rxrpc_timer_set_for_keepalive);
}
/*
* Fill out an ACK packet.
*/
static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
struct rxrpc_call *call,
struct rxrpc_ack_buffer *pkt,
rxrpc_seq_t *_hard_ack,
rxrpc_seq_t *_top,
u8 reason)
{
rxrpc_serial_t serial;
unsigned int tmp;
rxrpc_seq_t hard_ack, top, seq;
int ix;
u32 mtu, jmax;
u8 *ackp = pkt->acks;
tmp = atomic_xchg(&call->ackr_nr_unacked, 0);
tmp |= atomic_xchg(&call->ackr_nr_consumed, 0);
if (!tmp && (reason == RXRPC_ACK_DELAY ||
reason == RXRPC_ACK_IDLE))
return 0;
/* 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(0);
pkt->ack.maxSkew = htons(0);
pkt->ack.firstPacket = htonl(hard_ack + 1);
pkt->ack.previousPacket = htonl(call->ackr_highest_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 = conn->params.peer->if_mtu;
mtu -= 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;
}
/*
* Record the beginning of an RTT probe.
*/
static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
enum rxrpc_rtt_tx_trace why)
{
unsigned long avail = call->rtt_avail;
int rtt_slot = 9;
if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
goto no_slot;
rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
goto no_slot;
call->rtt_serial[rtt_slot] = serial;
call->rtt_sent_at[rtt_slot] = ktime_get_real();
smp_wmb(); /* Write data before avail bit */
set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
return rtt_slot;
no_slot:
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
return -1;
}
/*
* Cancel an RTT probe.
*/
static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call,
rxrpc_serial_t serial, int rtt_slot)
{
if (rtt_slot != -1) {
clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
smp_wmb(); /* Clear pending bit before setting slot */
set_bit(rtt_slot, &call->rtt_avail);
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial);
}
}
/*
* Send an ACK call packet.
*/
int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
rxrpc_serial_t *_serial)
{
struct rxrpc_connection *conn;
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, rtt_slot = -1;
u8 reason;
if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
return -ECONNRESET;
pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
if (!pkt)
return -ENOMEM;
conn = call->conn;
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(conn, call, pkt, &hard_ack, &top, reason);
spin_unlock_bh(&call->lock);
if (n == 0) {
kfree(pkt);
return 0;
}
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->debug_id, serial,
ntohl(pkt->ack.firstPacket),
ntohl(pkt->ack.serial),
pkt->ack.reason, pkt->ack.nAcks);
if (_serial)
*_serial = serial;
if (ping)
rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
conn->params.peer->last_tx_at = ktime_get_seconds();
if (ret < 0)
trace_rxrpc_tx_fail(call->debug_id, serial, ret,
rxrpc_tx_point_call_ack);
else
trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
rxrpc_tx_point_call_ack);
rxrpc_tx_backoff(call, ret);
if (call->state < RXRPC_CALL_COMPLETE) {
if (ret < 0) {
rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
rxrpc_propose_ACK(call, pkt->ack.reason,
ntohl(pkt->ack.serial),
false, true,
rxrpc_propose_ack_retry_tx);
}
rxrpc_set_keepalive(call);
}
out:
kfree(pkt);
return ret;
}
/*
* Send an ABORT call packet.
*/
int rxrpc_send_abort_packet(struct rxrpc_call *call)
{
struct rxrpc_connection *conn;
struct rxrpc_abort_buffer pkt;
struct msghdr msg;
struct kvec iov[1];
rxrpc_serial_t serial;
int ret;
/* Don't bother sending aborts for a client call once the server has
* hard-ACK'd all of its request data. After that point, we're not
* going to stop the operation proceeding, and whilst we might limit
* the reply, it's not worth it if we can send a new call on the same
* channel instead, thereby closing off this call.
*/
if (rxrpc_is_client_call(call) &&
test_bit(RXRPC_CALL_TX_LAST, &call->flags))
return 0;
if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
return -ECONNRESET;
conn = call->conn;
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));
conn->params.peer->last_tx_at = ktime_get_seconds();
if (ret < 0)
trace_rxrpc_tx_fail(call->debug_id, serial, ret,
rxrpc_tx_point_call_abort);
else
trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
rxrpc_tx_point_call_abort);
rxrpc_tx_backoff(call, ret);
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;
int ret, rtt_slot = -1;
_enter(",{%d}", skb->len);
if (hlist_unhashed(&call->error_link)) {
spin_lock_bh(&call->peer->lock);
hlist_add_head_rcu(&call->error_link, &call->peer->error_targets);
spin_unlock_bh(&call->peer->lock);
}
/* 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);
if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
sp->hdr.seq == 1)
whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
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.
*
* However, we mustn't request an ACK on the last reply packet of a
* service call, lest OpenAFS incorrectly send us an ACK with some
* soft-ACKs in it and then never follow up with a proper hard ACK.
*/
if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
rxrpc_to_server(sp)
) &&
(test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
retrans ||
call->cong_mode == RXRPC_CALL_SLOW_START ||
(call->peer->rtt_count < 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;
trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
whdr.flags, retrans, true);
goto done;
}
}
trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
false);
/* 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);
sp->hdr.serial = serial;
smp_wmb(); /* Set serial before timestamp */
skb->tstamp = ktime_get_real();
if (whdr.flags & RXRPC_REQUEST_ACK)
rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
/* 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);
conn->params.peer->last_tx_at = ktime_get_seconds();
up_read(&conn->params.local->defrag_sem);
if (ret < 0) {
rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
trace_rxrpc_tx_fail(call->debug_id, serial, ret,
rxrpc_tx_point_call_data_nofrag);
} else {
trace_rxrpc_tx_packet(call->debug_id, &whdr,
rxrpc_tx_point_call_data_nofrag);
}
rxrpc_tx_backoff(call, ret);
if (ret == -EMSGSIZE)
goto send_fragmentable;
done:
if (ret >= 0) {
if (whdr.flags & RXRPC_REQUEST_ACK) {
call->peer->rtt_last_req = skb->tstamp;
if (call->peer->rtt_count > 1) {
unsigned long nowj = jiffies, ack_lost_at;
ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
ack_lost_at += nowj;
WRITE_ONCE(call->ack_lost_at, ack_lost_at);
rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
rxrpc_timer_set_for_lost_ack);
}
}
if (sp->hdr.seq == 1 &&
!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
&call->flags)) {
unsigned long nowj = jiffies, expect_rx_by;
expect_rx_by = nowj + call->next_rx_timo;
WRITE_ONCE(call->expect_rx_by, expect_rx_by);
rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
rxrpc_timer_set_for_normal);
}
rxrpc_set_keepalive(call);
} else {
/* Cancel the call if the initial transmission fails,
* particularly if that's due to network routing issues that
* aren't going away anytime soon. The layer above can arrange
* the retransmission.
*/
if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
RX_USER_ABORT, ret);
}
_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);
sp->hdr.serial = serial;
smp_wmb(); /* Set serial before timestamp */
skb->tstamp = ktime_get_real();
if (whdr.flags & RXRPC_REQUEST_ACK)
rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
switch (conn->params.local->srx.transport.family) {
case AF_INET6:
case AF_INET:
ip_sock_set_mtu_discover(conn->params.local->socket->sk,
IP_PMTUDISC_DONT);
ret = kernel_sendmsg(conn->params.local->socket, &msg,
iov, 2, len);
conn->params.peer->last_tx_at = ktime_get_seconds();
ip_sock_set_mtu_discover(conn->params.local->socket->sk,
IP_PMTUDISC_DO);
break;
default:
BUG();
}
if (ret < 0) {
rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
trace_rxrpc_tx_fail(call->debug_id, serial, ret,
rxrpc_tx_point_call_data_frag);
} else {
trace_rxrpc_tx_packet(call->debug_id, &whdr,
rxrpc_tx_point_call_data_frag);
}
rxrpc_tx_backoff(call, ret);
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;
int ret, ioc;
_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);
msg.msg_name = &srx.transport;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
memset(&whdr, 0, sizeof(whdr));
while ((skb = skb_dequeue(&local->reject_queue))) {
rxrpc_see_skb(skb, rxrpc_skb_seen);
sp = rxrpc_skb(skb);
switch (skb->mark) {
case RXRPC_SKB_MARK_REJECT_BUSY:
whdr.type = RXRPC_PACKET_TYPE_BUSY;
size = sizeof(whdr);
ioc = 1;
break;
case RXRPC_SKB_MARK_REJECT_ABORT:
whdr.type = RXRPC_PACKET_TYPE_ABORT;
code = htonl(skb->priority);
size = sizeof(whdr) + sizeof(code);
ioc = 2;
break;
default:
rxrpc_free_skb(skb, rxrpc_skb_freed);
continue;
}
if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
msg.msg_namelen = srx.transport_len;
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;
ret = kernel_sendmsg(local->socket, &msg,
iov, ioc, size);
if (ret < 0)
trace_rxrpc_tx_fail(local->debug_id, 0, ret,
rxrpc_tx_point_reject);
else
trace_rxrpc_tx_packet(local->debug_id, &whdr,
rxrpc_tx_point_reject);
}
rxrpc_free_skb(skb, rxrpc_skb_freed);
}
_leave("");
}
/*
* Send a VERSION reply to a peer as a keepalive.
*/
void rxrpc_send_keepalive(struct rxrpc_peer *peer)
{
struct rxrpc_wire_header whdr;
struct msghdr msg;
struct kvec iov[2];
size_t len;
int ret;
_enter("");
msg.msg_name = &peer->srx.transport;
msg.msg_namelen = peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
whdr.epoch = htonl(peer->local->rxnet->epoch);
whdr.cid = 0;
whdr.callNumber = 0;
whdr.seq = 0;
whdr.serial = 0;
whdr.type = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
whdr.flags = RXRPC_LAST_PACKET;
whdr.userStatus = 0;
whdr.securityIndex = 0;
whdr._rsvd = 0;
whdr.serviceId = 0;
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = (char *)rxrpc_keepalive_string;
iov[1].iov_len = sizeof(rxrpc_keepalive_string);
len = iov[0].iov_len + iov[1].iov_len;
_proto("Tx VERSION (keepalive)");
ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
if (ret < 0)
trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
rxrpc_tx_point_version_keepalive);
else
trace_rxrpc_tx_packet(peer->debug_id, &whdr,
rxrpc_tx_point_version_keepalive);
peer->last_tx_at = ktime_get_seconds();
_leave("");
}
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