blob: 8e0b94714e849f24ade14efd349eb4447cfeb899 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/* AF_RXRPC sendmsg() implementation.
*
* Copyright (C) 2007, 2016 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 <linux/sched/signal.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
/*
* Propose an abort to be made in the I/O thread.
*/
bool rxrpc_propose_abort(struct rxrpc_call *call, s32 abort_code, int error,
enum rxrpc_abort_reason why)
{
_enter("{%d},%d,%d,%u", call->debug_id, abort_code, error, why);
if (!call->send_abort && !rxrpc_call_is_complete(call)) {
call->send_abort_why = why;
call->send_abort_err = error;
call->send_abort_seq = 0;
/* Request abort locklessly vs rxrpc_input_call_event(). */
smp_store_release(&call->send_abort, abort_code);
rxrpc_poke_call(call, rxrpc_call_poke_abort);
return true;
}
return false;
}
/*
* Wait for a call to become connected. Interruption here doesn't cause the
* call to be aborted.
*/
static int rxrpc_wait_to_be_connected(struct rxrpc_call *call, long *timeo)
{
DECLARE_WAITQUEUE(myself, current);
int ret = 0;
_enter("%d", call->debug_id);
if (rxrpc_call_state(call) != RXRPC_CALL_CLIENT_AWAIT_CONN)
goto no_wait;
add_wait_queue_exclusive(&call->waitq, &myself);
for (;;) {
switch (call->interruptibility) {
case RXRPC_INTERRUPTIBLE:
case RXRPC_PREINTERRUPTIBLE:
set_current_state(TASK_INTERRUPTIBLE);
break;
case RXRPC_UNINTERRUPTIBLE:
default:
set_current_state(TASK_UNINTERRUPTIBLE);
break;
}
if (rxrpc_call_state(call) != RXRPC_CALL_CLIENT_AWAIT_CONN)
break;
if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
signal_pending(current)) {
ret = sock_intr_errno(*timeo);
break;
}
*timeo = schedule_timeout(*timeo);
}
remove_wait_queue(&call->waitq, &myself);
__set_current_state(TASK_RUNNING);
no_wait:
if (ret == 0 && rxrpc_call_is_complete(call))
ret = call->error;
_leave(" = %d", ret);
return ret;
}
/*
* Return true if there's sufficient Tx queue space.
*/
static bool rxrpc_check_tx_space(struct rxrpc_call *call, rxrpc_seq_t *_tx_win)
{
if (_tx_win)
*_tx_win = call->tx_bottom;
return call->tx_prepared - call->tx_bottom < 256;
}
/*
* Wait for space to appear in the Tx queue or a signal to occur.
*/
static int rxrpc_wait_for_tx_window_intr(struct rxrpc_sock *rx,
struct rxrpc_call *call,
long *timeo)
{
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (rxrpc_check_tx_space(call, NULL))
return 0;
if (rxrpc_call_is_complete(call))
return call->error;
if (signal_pending(current))
return sock_intr_errno(*timeo);
trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
*timeo = schedule_timeout(*timeo);
}
}
/*
* Wait for space to appear in the Tx queue uninterruptibly, but with
* a timeout of 2*RTT if no progress was made and a signal occurred.
*/
static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
struct rxrpc_call *call)
{
rxrpc_seq_t tx_start, tx_win;
signed long rtt, timeout;
rtt = READ_ONCE(call->peer->srtt_us) >> 3;
rtt = usecs_to_jiffies(rtt) * 2;
if (rtt < 2)
rtt = 2;
timeout = rtt;
tx_start = smp_load_acquire(&call->acks_hard_ack);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (rxrpc_check_tx_space(call, &tx_win))
return 0;
if (rxrpc_call_is_complete(call))
return call->error;
if (timeout == 0 &&
tx_win == tx_start && signal_pending(current))
return -EINTR;
if (tx_win != tx_start) {
timeout = rtt;
tx_start = tx_win;
}
trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
timeout = schedule_timeout(timeout);
}
}
/*
* Wait for space to appear in the Tx queue uninterruptibly.
*/
static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
struct rxrpc_call *call,
long *timeo)
{
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (rxrpc_check_tx_space(call, NULL))
return 0;
if (rxrpc_call_is_complete(call))
return call->error;
trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
*timeo = schedule_timeout(*timeo);
}
}
/*
* wait for space to appear in the transmit/ACK window
* - caller holds the socket locked
*/
static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
struct rxrpc_call *call,
long *timeo,
bool waitall)
{
DECLARE_WAITQUEUE(myself, current);
int ret;
_enter(",{%u,%u,%u,%u}",
call->tx_bottom, call->acks_hard_ack, call->tx_top, call->tx_winsize);
add_wait_queue(&call->waitq, &myself);
switch (call->interruptibility) {
case RXRPC_INTERRUPTIBLE:
if (waitall)
ret = rxrpc_wait_for_tx_window_waitall(rx, call);
else
ret = rxrpc_wait_for_tx_window_intr(rx, call, timeo);
break;
case RXRPC_PREINTERRUPTIBLE:
case RXRPC_UNINTERRUPTIBLE:
default:
ret = rxrpc_wait_for_tx_window_nonintr(rx, call, timeo);
break;
}
remove_wait_queue(&call->waitq, &myself);
set_current_state(TASK_RUNNING);
_leave(" = %d", ret);
return ret;
}
/*
* Notify the owner of the call that the transmit phase is ended and the last
* packet has been queued.
*/
static void rxrpc_notify_end_tx(struct rxrpc_sock *rx, struct rxrpc_call *call,
rxrpc_notify_end_tx_t notify_end_tx)
{
if (notify_end_tx)
notify_end_tx(&rx->sk, call, call->user_call_ID);
}
/*
* Queue a DATA packet for transmission, set the resend timeout and send
* the packet immediately. Returns the error from rxrpc_send_data_packet()
* in case the caller wants to do something with it.
*/
static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
struct rxrpc_txbuf *txb,
rxrpc_notify_end_tx_t notify_end_tx)
{
rxrpc_seq_t seq = txb->seq;
bool last = test_bit(RXRPC_TXBUF_LAST, &txb->flags), poke;
rxrpc_inc_stat(call->rxnet, stat_tx_data);
ASSERTCMP(txb->seq, ==, call->tx_prepared + 1);
/* We have to set the timestamp before queueing as the retransmit
* algorithm can see the packet as soon as we queue it.
*/
txb->last_sent = ktime_get_real();
if (last)
trace_rxrpc_txqueue(call, rxrpc_txqueue_queue_last);
else
trace_rxrpc_txqueue(call, rxrpc_txqueue_queue);
/* Add the packet to the call's output buffer */
spin_lock(&call->tx_lock);
poke = list_empty(&call->tx_sendmsg);
list_add_tail(&txb->call_link, &call->tx_sendmsg);
call->tx_prepared = seq;
if (last)
rxrpc_notify_end_tx(rx, call, notify_end_tx);
spin_unlock(&call->tx_lock);
if (poke)
rxrpc_poke_call(call, rxrpc_call_poke_start);
}
/*
* send data through a socket
* - must be called in process context
* - The caller holds the call user access mutex, but not the socket lock.
*/
static int rxrpc_send_data(struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct msghdr *msg, size_t len,
rxrpc_notify_end_tx_t notify_end_tx,
bool *_dropped_lock)
{
struct rxrpc_txbuf *txb;
struct sock *sk = &rx->sk;
enum rxrpc_call_state state;
long timeo;
bool more = msg->msg_flags & MSG_MORE;
int ret, copied = 0;
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
ret = rxrpc_wait_to_be_connected(call, &timeo);
if (ret < 0)
return ret;
if (call->conn->state == RXRPC_CONN_CLIENT_UNSECURED) {
ret = rxrpc_init_client_conn_security(call->conn);
if (ret < 0)
return ret;
}
/* this should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
reload:
ret = -EPIPE;
if (sk->sk_shutdown & SEND_SHUTDOWN)
goto maybe_error;
state = rxrpc_call_state(call);
ret = -ESHUTDOWN;
if (state >= RXRPC_CALL_COMPLETE)
goto maybe_error;
ret = -EPROTO;
if (state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
state != RXRPC_CALL_SERVER_ACK_REQUEST &&
state != RXRPC_CALL_SERVER_SEND_REPLY) {
/* Request phase complete for this client call */
trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_late_send,
call->cid, call->call_id, call->rx_consumed,
0, -EPROTO);
goto maybe_error;
}
ret = -EMSGSIZE;
if (call->tx_total_len != -1) {
if (len - copied > call->tx_total_len)
goto maybe_error;
if (!more && len - copied != call->tx_total_len)
goto maybe_error;
}
txb = call->tx_pending;
call->tx_pending = NULL;
if (txb)
rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
do {
if (!txb) {
size_t remain, bufsize, chunk, offset;
_debug("alloc");
if (!rxrpc_check_tx_space(call, NULL))
goto wait_for_space;
/* Work out the maximum size of a packet. Assume that
* the security header is going to be in the padded
* region (enc blocksize), but the trailer is not.
*/
remain = more ? INT_MAX : msg_data_left(msg);
ret = call->conn->security->how_much_data(call, remain,
&bufsize, &chunk, &offset);
if (ret < 0)
goto maybe_error;
_debug("SIZE: %zu/%zu @%zu", chunk, bufsize, offset);
/* create a buffer that we can retain until it's ACK'd */
ret = -ENOMEM;
txb = rxrpc_alloc_txbuf(call, RXRPC_PACKET_TYPE_DATA,
GFP_KERNEL);
if (!txb)
goto maybe_error;
txb->offset = offset;
txb->space -= offset;
txb->space = min_t(size_t, chunk, txb->space);
}
_debug("append");
/* append next segment of data to the current buffer */
if (msg_data_left(msg) > 0) {
size_t copy = min_t(size_t, txb->space, msg_data_left(msg));
_debug("add %zu", copy);
if (!copy_from_iter_full(txb->data + txb->offset, copy,
&msg->msg_iter))
goto efault;
_debug("added");
txb->space -= copy;
txb->len += copy;
txb->offset += copy;
copied += copy;
if (call->tx_total_len != -1)
call->tx_total_len -= copy;
}
/* check for the far side aborting the call or a network error
* occurring */
if (rxrpc_call_is_complete(call))
goto call_terminated;
/* add the packet to the send queue if it's now full */
if (!txb->space ||
(msg_data_left(msg) == 0 && !more)) {
if (msg_data_left(msg) == 0 && !more) {
txb->wire.flags |= RXRPC_LAST_PACKET;
__set_bit(RXRPC_TXBUF_LAST, &txb->flags);
}
else if (call->tx_top - call->acks_hard_ack <
call->tx_winsize)
txb->wire.flags |= RXRPC_MORE_PACKETS;
ret = call->security->secure_packet(call, txb);
if (ret < 0)
goto out;
rxrpc_queue_packet(rx, call, txb, notify_end_tx);
txb = NULL;
}
} while (msg_data_left(msg) > 0);
success:
ret = copied;
if (rxrpc_call_is_complete(call) &&
call->error < 0)
ret = call->error;
out:
call->tx_pending = txb;
_leave(" = %d", ret);
return ret;
call_terminated:
rxrpc_put_txbuf(txb, rxrpc_txbuf_put_send_aborted);
_leave(" = %d", call->error);
return call->error;
maybe_error:
if (copied)
goto success;
goto out;
efault:
ret = -EFAULT;
goto out;
wait_for_space:
ret = -EAGAIN;
if (msg->msg_flags & MSG_DONTWAIT)
goto maybe_error;
mutex_unlock(&call->user_mutex);
*_dropped_lock = true;
ret = rxrpc_wait_for_tx_window(rx, call, &timeo,
msg->msg_flags & MSG_WAITALL);
if (ret < 0)
goto maybe_error;
if (call->interruptibility == RXRPC_INTERRUPTIBLE) {
if (mutex_lock_interruptible(&call->user_mutex) < 0) {
ret = sock_intr_errno(timeo);
goto maybe_error;
}
} else {
mutex_lock(&call->user_mutex);
}
*_dropped_lock = false;
goto reload;
}
/*
* extract control messages from the sendmsg() control buffer
*/
static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
{
struct cmsghdr *cmsg;
bool got_user_ID = false;
int len;
if (msg->msg_controllen == 0)
return -EINVAL;
for_each_cmsghdr(cmsg, msg) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
len = cmsg->cmsg_len - sizeof(struct cmsghdr);
_debug("CMSG %d, %d, %d",
cmsg->cmsg_level, cmsg->cmsg_type, len);
if (cmsg->cmsg_level != SOL_RXRPC)
continue;
switch (cmsg->cmsg_type) {
case RXRPC_USER_CALL_ID:
if (msg->msg_flags & MSG_CMSG_COMPAT) {
if (len != sizeof(u32))
return -EINVAL;
p->call.user_call_ID = *(u32 *)CMSG_DATA(cmsg);
} else {
if (len != sizeof(unsigned long))
return -EINVAL;
p->call.user_call_ID = *(unsigned long *)
CMSG_DATA(cmsg);
}
got_user_ID = true;
break;
case RXRPC_ABORT:
if (p->command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
p->command = RXRPC_CMD_SEND_ABORT;
if (len != sizeof(p->abort_code))
return -EINVAL;
p->abort_code = *(unsigned int *)CMSG_DATA(cmsg);
if (p->abort_code == 0)
return -EINVAL;
break;
case RXRPC_CHARGE_ACCEPT:
if (p->command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
p->command = RXRPC_CMD_CHARGE_ACCEPT;
if (len != 0)
return -EINVAL;
break;
case RXRPC_EXCLUSIVE_CALL:
p->exclusive = true;
if (len != 0)
return -EINVAL;
break;
case RXRPC_UPGRADE_SERVICE:
p->upgrade = true;
if (len != 0)
return -EINVAL;
break;
case RXRPC_TX_LENGTH:
if (p->call.tx_total_len != -1 || len != sizeof(__s64))
return -EINVAL;
p->call.tx_total_len = *(__s64 *)CMSG_DATA(cmsg);
if (p->call.tx_total_len < 0)
return -EINVAL;
break;
case RXRPC_SET_CALL_TIMEOUT:
if (len & 3 || len < 4 || len > 12)
return -EINVAL;
memcpy(&p->call.timeouts, CMSG_DATA(cmsg), len);
p->call.nr_timeouts = len / 4;
if (p->call.timeouts.hard > INT_MAX / HZ)
return -ERANGE;
if (p->call.nr_timeouts >= 2 && p->call.timeouts.idle > 60 * 60 * 1000)
return -ERANGE;
if (p->call.nr_timeouts >= 3 && p->call.timeouts.normal > 60 * 60 * 1000)
return -ERANGE;
break;
default:
return -EINVAL;
}
}
if (!got_user_ID)
return -EINVAL;
if (p->call.tx_total_len != -1 && p->command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
_leave(" = 0");
return 0;
}
/*
* Create a new client call for sendmsg().
* - Called with the socket lock held, which it must release.
* - If it returns a call, the call's lock will need releasing by the caller.
*/
static struct rxrpc_call *
rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
struct rxrpc_send_params *p)
__releases(&rx->sk.sk_lock.slock)
__acquires(&call->user_mutex)
{
struct rxrpc_conn_parameters cp;
struct rxrpc_call *call;
struct key *key;
DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
_enter("");
if (!msg->msg_name) {
release_sock(&rx->sk);
return ERR_PTR(-EDESTADDRREQ);
}
key = rx->key;
if (key && !rx->key->payload.data[0])
key = NULL;
memset(&cp, 0, sizeof(cp));
cp.local = rx->local;
cp.key = rx->key;
cp.security_level = rx->min_sec_level;
cp.exclusive = rx->exclusive | p->exclusive;
cp.upgrade = p->upgrade;
cp.service_id = srx->srx_service;
call = rxrpc_new_client_call(rx, &cp, srx, &p->call, GFP_KERNEL,
atomic_inc_return(&rxrpc_debug_id));
/* The socket is now unlocked */
_leave(" = %p\n", call);
return call;
}
/*
* send a message forming part of a client call through an RxRPC socket
* - caller holds the socket locked
* - the socket may be either a client socket or a server socket
*/
int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
__releases(&rx->sk.sk_lock.slock)
{
struct rxrpc_call *call;
unsigned long now, j;
bool dropped_lock = false;
int ret;
struct rxrpc_send_params p = {
.call.tx_total_len = -1,
.call.user_call_ID = 0,
.call.nr_timeouts = 0,
.call.interruptibility = RXRPC_INTERRUPTIBLE,
.abort_code = 0,
.command = RXRPC_CMD_SEND_DATA,
.exclusive = false,
.upgrade = false,
};
_enter("");
ret = rxrpc_sendmsg_cmsg(msg, &p);
if (ret < 0)
goto error_release_sock;
if (p.command == RXRPC_CMD_CHARGE_ACCEPT) {
ret = -EINVAL;
if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
goto error_release_sock;
ret = rxrpc_user_charge_accept(rx, p.call.user_call_ID);
goto error_release_sock;
}
call = rxrpc_find_call_by_user_ID(rx, p.call.user_call_ID);
if (!call) {
ret = -EBADSLT;
if (p.command != RXRPC_CMD_SEND_DATA)
goto error_release_sock;
call = rxrpc_new_client_call_for_sendmsg(rx, msg, &p);
/* The socket is now unlocked... */
if (IS_ERR(call))
return PTR_ERR(call);
/* ... and we have the call lock. */
p.call.nr_timeouts = 0;
ret = 0;
if (rxrpc_call_is_complete(call))
goto out_put_unlock;
} else {
switch (rxrpc_call_state(call)) {
case RXRPC_CALL_CLIENT_AWAIT_CONN:
case RXRPC_CALL_SERVER_SECURING:
if (p.command == RXRPC_CMD_SEND_ABORT)
break;
fallthrough;
case RXRPC_CALL_UNINITIALISED:
case RXRPC_CALL_SERVER_PREALLOC:
rxrpc_put_call(call, rxrpc_call_put_sendmsg);
ret = -EBUSY;
goto error_release_sock;
default:
break;
}
ret = mutex_lock_interruptible(&call->user_mutex);
release_sock(&rx->sk);
if (ret < 0) {
ret = -ERESTARTSYS;
goto error_put;
}
if (p.call.tx_total_len != -1) {
ret = -EINVAL;
if (call->tx_total_len != -1 ||
call->tx_pending ||
call->tx_top != 0)
goto out_put_unlock;
call->tx_total_len = p.call.tx_total_len;
}
}
switch (p.call.nr_timeouts) {
case 3:
j = msecs_to_jiffies(p.call.timeouts.normal);
if (p.call.timeouts.normal > 0 && j == 0)
j = 1;
WRITE_ONCE(call->next_rx_timo, j);
fallthrough;
case 2:
j = msecs_to_jiffies(p.call.timeouts.idle);
if (p.call.timeouts.idle > 0 && j == 0)
j = 1;
WRITE_ONCE(call->next_req_timo, j);
fallthrough;
case 1:
if (p.call.timeouts.hard > 0) {
j = p.call.timeouts.hard * HZ;
now = jiffies;
j += now;
WRITE_ONCE(call->expect_term_by, j);
rxrpc_reduce_call_timer(call, j, now,
rxrpc_timer_set_for_hard);
}
break;
}
if (rxrpc_call_is_complete(call)) {
/* it's too late for this call */
ret = -ESHUTDOWN;
} else if (p.command == RXRPC_CMD_SEND_ABORT) {
rxrpc_propose_abort(call, p.abort_code, -ECONNABORTED,
rxrpc_abort_call_sendmsg);
ret = 0;
} else if (p.command != RXRPC_CMD_SEND_DATA) {
ret = -EINVAL;
} else {
ret = rxrpc_send_data(rx, call, msg, len, NULL, &dropped_lock);
}
out_put_unlock:
if (!dropped_lock)
mutex_unlock(&call->user_mutex);
error_put:
rxrpc_put_call(call, rxrpc_call_put_sendmsg);
_leave(" = %d", ret);
return ret;
error_release_sock:
release_sock(&rx->sk);
return ret;
}
/**
* rxrpc_kernel_send_data - Allow a kernel service to send data on a call
* @sock: The socket the call is on
* @call: The call to send data through
* @msg: The data to send
* @len: The amount of data to send
* @notify_end_tx: Notification that the last packet is queued.
*
* Allow a kernel service to send data on a call. The call must be in an state
* appropriate to sending data. No control data should be supplied in @msg,
* nor should an address be supplied. MSG_MORE should be flagged if there's
* more data to come, otherwise this data will end the transmission phase.
*/
int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
struct msghdr *msg, size_t len,
rxrpc_notify_end_tx_t notify_end_tx)
{
bool dropped_lock = false;
int ret;
_enter("{%d},", call->debug_id);
ASSERTCMP(msg->msg_name, ==, NULL);
ASSERTCMP(msg->msg_control, ==, NULL);
mutex_lock(&call->user_mutex);
ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
notify_end_tx, &dropped_lock);
if (ret == -ESHUTDOWN)
ret = call->error;
if (!dropped_lock)
mutex_unlock(&call->user_mutex);
_leave(" = %d", ret);
return ret;
}
EXPORT_SYMBOL(rxrpc_kernel_send_data);
/**
* rxrpc_kernel_abort_call - Allow a kernel service to abort a call
* @sock: The socket the call is on
* @call: The call to be aborted
* @abort_code: The abort code to stick into the ABORT packet
* @error: Local error value
* @why: Indication as to why.
*
* Allow a kernel service to abort a call, if it's still in an abortable state
* and return true if the call was aborted, false if it was already complete.
*/
bool rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
u32 abort_code, int error, enum rxrpc_abort_reason why)
{
bool aborted;
_enter("{%d},%d,%d,%u", call->debug_id, abort_code, error, why);
mutex_lock(&call->user_mutex);
aborted = rxrpc_propose_abort(call, abort_code, error, why);
mutex_unlock(&call->user_mutex);
return aborted;
}
EXPORT_SYMBOL(rxrpc_kernel_abort_call);
/**
* rxrpc_kernel_set_tx_length - Set the total Tx length on a call
* @sock: The socket the call is on
* @call: The call to be informed
* @tx_total_len: The amount of data to be transmitted for this call
*
* Allow a kernel service to set the total transmit length on a call. This
* allows buffer-to-packet encrypt-and-copy to be performed.
*
* This function is primarily for use for setting the reply length since the
* request length can be set when beginning the call.
*/
void rxrpc_kernel_set_tx_length(struct socket *sock, struct rxrpc_call *call,
s64 tx_total_len)
{
WARN_ON(call->tx_total_len != -1);
call->tx_total_len = tx_total_len;
}
EXPORT_SYMBOL(rxrpc_kernel_set_tx_length);