linux/net/rxrpc/output.c
David Howells cb0fc0c972 rxrpc: trace: Don't use __builtin_return_address for rxrpc_call tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_call tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00

715 lines
20 KiB
C

// 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 <net/udp.h>
#include "ar-internal.h"
extern int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
static ssize_t do_udp_sendmsg(struct socket *socket, struct msghdr *msg, size_t len)
{
struct sockaddr *sa = msg->msg_name;
struct sock *sk = socket->sk;
if (IS_ENABLED(CONFIG_AF_RXRPC_IPV6)) {
if (sa->sa_family == AF_INET6) {
if (sk->sk_family != AF_INET6) {
pr_warn("AF_INET6 address on AF_INET socket\n");
return -ENOPROTOOPT;
}
return udpv6_sendmsg(sk, msg, len);
}
}
return udp_sendmsg(sk, msg, len);
}
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_txbuf *txb)
{
struct rxrpc_ackinfo ackinfo;
unsigned int qsize;
rxrpc_seq_t window, wtop, wrap_point, ix, first;
int rsize;
u64 wtmp;
u32 mtu, jmax;
u8 *ackp = txb->acks;
u8 sack_buffer[sizeof(call->ackr_sack_table)] __aligned(8);
atomic_set(&call->ackr_nr_unacked, 0);
atomic_set(&call->ackr_nr_consumed, 0);
rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill);
/* Barrier against rxrpc_input_data(). */
retry:
wtmp = atomic64_read_acquire(&call->ackr_window);
window = lower_32_bits(wtmp);
wtop = upper_32_bits(wtmp);
txb->ack.firstPacket = htonl(window);
txb->ack.nAcks = 0;
if (after(wtop, window)) {
/* Try to copy the SACK ring locklessly. We can use the copy,
* only if the now-current top of the window didn't go past the
* previously read base - otherwise we can't know whether we
* have old data or new data.
*/
memcpy(sack_buffer, call->ackr_sack_table, sizeof(sack_buffer));
wrap_point = window + RXRPC_SACK_SIZE - 1;
wtmp = atomic64_read_acquire(&call->ackr_window);
window = lower_32_bits(wtmp);
wtop = upper_32_bits(wtmp);
if (after(wtop, wrap_point)) {
cond_resched();
goto retry;
}
/* The buffer is maintained as a ring with an invariant mapping
* between bit position and sequence number, so we'll probably
* need to rotate it.
*/
txb->ack.nAcks = wtop - window;
ix = window % RXRPC_SACK_SIZE;
first = sizeof(sack_buffer) - ix;
if (ix + txb->ack.nAcks <= RXRPC_SACK_SIZE) {
memcpy(txb->acks, sack_buffer + ix, txb->ack.nAcks);
} else {
memcpy(txb->acks, sack_buffer + ix, first);
memcpy(txb->acks + first, sack_buffer,
txb->ack.nAcks - first);
}
ackp += txb->ack.nAcks;
} else if (before(wtop, window)) {
pr_warn("ack window backward %x %x", window, wtop);
} else if (txb->ack.reason == RXRPC_ACK_DELAY) {
txb->ack.reason = RXRPC_ACK_IDLE;
}
mtu = conn->peer->if_mtu;
mtu -= conn->peer->hdrsize;
jmax = rxrpc_rx_jumbo_max;
qsize = (window - 1) - call->rx_consumed;
rsize = max_t(int, call->rx_winsize - qsize, 0);
ackinfo.rxMTU = htonl(rxrpc_rx_mtu);
ackinfo.maxMTU = htonl(mtu);
ackinfo.rwind = htonl(rsize);
ackinfo.jumbo_max = htonl(jmax);
*ackp++ = 0;
*ackp++ = 0;
*ackp++ = 0;
memcpy(ackp, &ackinfo, sizeof(ackinfo));
return txb->ack.nAcks + 3 + sizeof(ackinfo);
}
/*
* 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.
*/
static int rxrpc_send_ack_packet(struct rxrpc_local *local, struct rxrpc_txbuf *txb)
{
struct rxrpc_connection *conn;
struct rxrpc_call *call = txb->call;
struct msghdr msg;
struct kvec iov[1];
rxrpc_serial_t serial;
size_t len, n;
int ret, rtt_slot = -1;
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;
if (txb->ack.reason == RXRPC_ACK_PING)
txb->wire.flags |= RXRPC_REQUEST_ACK;
if (txb->ack.reason == RXRPC_ACK_DELAY)
clear_bit(RXRPC_CALL_DELAY_ACK_PENDING, &call->flags);
if (txb->ack.reason == RXRPC_ACK_IDLE)
clear_bit(RXRPC_CALL_IDLE_ACK_PENDING, &call->flags);
n = rxrpc_fill_out_ack(conn, call, txb);
if (n == 0)
return 0;
iov[0].iov_base = &txb->wire;
iov[0].iov_len = sizeof(txb->wire) + sizeof(txb->ack) + n;
len = iov[0].iov_len;
serial = atomic_inc_return(&conn->serial);
txb->wire.serial = htonl(serial);
trace_rxrpc_tx_ack(call->debug_id, serial,
ntohl(txb->ack.firstPacket),
ntohl(txb->ack.serial), txb->ack.reason, txb->ack.nAcks);
if (txb->ack_why == rxrpc_propose_ack_ping_for_lost_ack)
call->acks_lost_ping = serial;
if (txb->ack.reason == RXRPC_ACK_PING)
rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
rxrpc_inc_stat(call->rxnet, stat_tx_ack_send);
/* Grab the highest received seq as late as possible */
txb->ack.previousPacket = htonl(call->rx_highest_seq);
iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
ret = do_udp_sendmsg(conn->local->socket, &msg, len);
call->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, &txb->wire,
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_set_keepalive(call);
}
return ret;
}
/*
* ACK transmitter for a local endpoint. The UDP socket locks around each
* transmission, so we can only transmit one packet at a time, ACK, DATA or
* otherwise.
*/
void rxrpc_transmit_ack_packets(struct rxrpc_local *local)
{
LIST_HEAD(queue);
int ret;
rxrpc_see_local(local, rxrpc_local_see_tx_ack);
if (list_empty(&local->ack_tx_queue))
return;
spin_lock_bh(&local->ack_tx_lock);
list_splice_tail_init(&local->ack_tx_queue, &queue);
spin_unlock_bh(&local->ack_tx_lock);
while (!list_empty(&queue)) {
struct rxrpc_txbuf *txb =
list_entry(queue.next, struct rxrpc_txbuf, tx_link);
ret = rxrpc_send_ack_packet(local, txb);
if (ret < 0 && ret != -ECONNRESET) {
spin_lock_bh(&local->ack_tx_lock);
list_splice_init(&queue, &local->ack_tx_queue);
spin_unlock_bh(&local->ack_tx_lock);
break;
}
list_del_init(&txb->tx_link);
rxrpc_put_call(txb->call, rxrpc_call_put_send_ack);
rxrpc_put_txbuf(txb, rxrpc_txbuf_put_ack_tx);
}
}
/*
* 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_ALL_ACKED, &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);
iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, sizeof(pkt));
ret = do_udp_sendmsg(conn->local->socket, &msg, sizeof(pkt));
conn->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 rxrpc_txbuf *txb)
{
enum rxrpc_req_ack_trace why;
struct rxrpc_connection *conn = call->conn;
struct msghdr msg;
struct kvec iov[1];
rxrpc_serial_t serial;
size_t len;
int ret, rtt_slot = -1;
_enter("%x,{%d}", txb->seq, txb->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);
txb->wire.serial = htonl(serial);
if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
txb->seq == 1)
txb->wire.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
iov[0].iov_base = &txb->wire;
iov[0].iov_len = sizeof(txb->wire) + txb->len;
len = iov[0].iov_len;
iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, 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 (txb->wire.flags & RXRPC_REQUEST_ACK)
why = rxrpc_reqack_already_on;
else if (test_bit(RXRPC_TXBUF_LAST, &txb->flags) && rxrpc_sending_to_client(txb))
why = rxrpc_reqack_no_srv_last;
else if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
why = rxrpc_reqack_ack_lost;
else if (test_bit(RXRPC_TXBUF_RESENT, &txb->flags))
why = rxrpc_reqack_retrans;
else if (call->cong_mode == RXRPC_CALL_SLOW_START && call->cong_cwnd <= 2)
why = rxrpc_reqack_slow_start;
else if (call->tx_winsize <= 2)
why = rxrpc_reqack_small_txwin;
else if (call->peer->rtt_count < 3 && txb->seq & 1)
why = rxrpc_reqack_more_rtt;
else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime_get_real()))
why = rxrpc_reqack_old_rtt;
else
goto dont_set_request_ack;
rxrpc_inc_stat(call->rxnet, stat_why_req_ack[why]);
trace_rxrpc_req_ack(call->debug_id, txb->seq, why);
if (why != rxrpc_reqack_no_srv_last)
txb->wire.flags |= RXRPC_REQUEST_ACK;
dont_set_request_ack:
if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
static int lose;
if ((lose++ & 7) == 7) {
ret = 0;
trace_rxrpc_tx_data(call, txb->seq, serial,
txb->wire.flags,
test_bit(RXRPC_TXBUF_RESENT, &txb->flags),
true);
goto done;
}
}
trace_rxrpc_tx_data(call, txb->seq, serial, txb->wire.flags,
test_bit(RXRPC_TXBUF_RESENT, &txb->flags), false);
cmpxchg(&call->tx_transmitted, txb->seq - 1, txb->seq);
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
if (txb->len >= call->peer->maxdata)
goto send_fragmentable;
down_read(&conn->local->defrag_sem);
txb->last_sent = ktime_get_real();
if (txb->wire.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
*/
rxrpc_inc_stat(call->rxnet, stat_tx_data_send);
ret = do_udp_sendmsg(conn->local->socket, &msg, len);
conn->peer->last_tx_at = ktime_get_seconds();
up_read(&conn->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, &txb->wire,
rxrpc_tx_point_call_data_nofrag);
}
rxrpc_tx_backoff(call, ret);
if (ret == -EMSGSIZE)
goto send_fragmentable;
done:
if (ret >= 0) {
call->tx_last_sent = txb->last_sent;
if (txb->wire.flags & RXRPC_REQUEST_ACK) {
call->peer->rtt_last_req = txb->last_sent;
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 (txb->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->local->defrag_sem);
txb->last_sent = ktime_get_real();
if (txb->wire.flags & RXRPC_REQUEST_ACK)
rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
switch (conn->local->srx.transport.family) {
case AF_INET6:
case AF_INET:
ip_sock_set_mtu_discover(conn->local->socket->sk,
IP_PMTUDISC_DONT);
rxrpc_inc_stat(call->rxnet, stat_tx_data_send_frag);
ret = do_udp_sendmsg(conn->local->socket, &msg, len);
conn->peer->last_tx_at = ktime_get_seconds();
ip_sock_set_mtu_discover(conn->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, &txb->wire,
rxrpc_tx_point_call_data_frag);
}
rxrpc_tx_backoff(call, ret);
up_write(&conn->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;
iov_iter_kvec(&msg.msg_iter, WRITE, iov, ioc, size);
ret = do_udp_sendmsg(local->socket, &msg, 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;
iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
ret = do_udp_sendmsg(peer->local->socket, &msg, 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("");
}