linux/net/rxrpc/sendmsg.c
David Howells c038a58ccf rxrpc: Allow failed client calls to be retried
Allow a client call that failed on network error to be retried, provided
that the Tx queue still holds DATA packet 1.  This allows an operation to
be submitted to another server or another address for the same server
without having to repackage and re-encrypt the data so far processed.

Two new functions are provided:

 (1) rxrpc_kernel_check_call() - This is used to find out the completion
     state of a call to guess whether it can be retried and whether it
     should be retried.

 (2) rxrpc_kernel_retry_call() - Disconnect the call from its current
     connection, reset the state and submit it as a new client call to a
     new address.  The new address need not match the previous address.

A call may be retried even if all the data hasn't been loaded into it yet;
a partially constructed will be retained at the same point it was at when
an error condition was detected.  msg_data_left() can be used to find out
how much data was packaged before the error occurred.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-08-29 10:55:20 +01:00

749 lines
19 KiB
C

/* AF_RXRPC sendmsg() implementation.
*
* Copyright (C) 2007, 2016 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, 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 <linux/sched/signal.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
enum rxrpc_command {
RXRPC_CMD_SEND_DATA, /* send data message */
RXRPC_CMD_SEND_ABORT, /* request abort generation */
RXRPC_CMD_ACCEPT, /* [server] accept incoming call */
RXRPC_CMD_REJECT_BUSY, /* [server] reject a call as busy */
};
struct rxrpc_send_params {
s64 tx_total_len; /* Total Tx data length (if send data) */
unsigned long user_call_ID; /* User's call ID */
u32 abort_code; /* Abort code to Tx (if abort) */
enum rxrpc_command command : 8; /* The command to implement */
bool exclusive; /* Shared or exclusive call */
bool upgrade; /* If the connection is upgradeable */
};
/*
* 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)
{
DECLARE_WAITQUEUE(myself, current);
int ret;
_enter(",{%u,%u,%u}",
call->tx_hard_ack, call->tx_top, call->tx_winsize);
add_wait_queue(&call->waitq, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
ret = 0;
if (call->tx_top - call->tx_hard_ack <
min_t(unsigned int, call->tx_winsize,
call->cong_cwnd + call->cong_extra))
break;
if (call->state >= RXRPC_CALL_COMPLETE) {
ret = call->error;
break;
}
if (signal_pending(current)) {
ret = sock_intr_errno(*timeo);
break;
}
trace_rxrpc_transmit(call, rxrpc_transmit_wait);
mutex_unlock(&call->user_mutex);
*timeo = schedule_timeout(*timeo);
if (mutex_lock_interruptible(&call->user_mutex) < 0) {
ret = sock_intr_errno(*timeo);
break;
}
}
remove_wait_queue(&call->waitq, &myself);
set_current_state(TASK_RUNNING);
_leave(" = %d", ret);
return ret;
}
/*
* Schedule an instant Tx resend.
*/
static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
{
spin_lock_bh(&call->lock);
if (call->state < RXRPC_CALL_COMPLETE) {
call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
rxrpc_queue_call(call);
}
spin_unlock_bh(&call->lock);
}
/*
* 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
*/
static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
struct sk_buff *skb, bool last,
rxrpc_notify_end_tx_t notify_end_tx)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
rxrpc_seq_t seq = sp->hdr.seq;
int ret, ix;
u8 annotation = RXRPC_TX_ANNO_UNACK;
_net("queue skb %p [%d]", skb, seq);
ASSERTCMP(seq, ==, call->tx_top + 1);
if (last) {
annotation |= RXRPC_TX_ANNO_LAST;
set_bit(RXRPC_CALL_TX_LASTQ, &call->flags);
}
/* We have to set the timestamp before queueing as the retransmit
* algorithm can see the packet as soon as we queue it.
*/
skb->tstamp = ktime_get_real();
ix = seq & RXRPC_RXTX_BUFF_MASK;
rxrpc_get_skb(skb, rxrpc_skb_tx_got);
call->rxtx_annotations[ix] = annotation;
smp_wmb();
call->rxtx_buffer[ix] = skb;
call->tx_top = seq;
if (last)
trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
else
trace_rxrpc_transmit(call, rxrpc_transmit_queue);
if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
_debug("________awaiting reply/ACK__________");
write_lock_bh(&call->state_lock);
switch (call->state) {
case RXRPC_CALL_CLIENT_SEND_REQUEST:
call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
rxrpc_notify_end_tx(rx, call, notify_end_tx);
break;
case RXRPC_CALL_SERVER_ACK_REQUEST:
call->state = RXRPC_CALL_SERVER_SEND_REPLY;
call->ack_at = call->expire_at;
if (call->ackr_reason == RXRPC_ACK_DELAY)
call->ackr_reason = 0;
__rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply,
ktime_get_real());
if (!last)
break;
case RXRPC_CALL_SERVER_SEND_REPLY:
call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
rxrpc_notify_end_tx(rx, call, notify_end_tx);
break;
default:
break;
}
write_unlock_bh(&call->state_lock);
}
if (seq == 1 && rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
ret = rxrpc_send_data_packet(call, skb, false);
if (ret < 0) {
_debug("need instant resend %d", ret);
rxrpc_instant_resend(call, ix);
} else {
ktime_t now = ktime_get_real(), resend_at;
resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
if (ktime_before(resend_at, call->resend_at)) {
call->resend_at = resend_at;
rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
}
}
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
_leave("");
}
/*
* 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)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
struct sock *sk = &rx->sk;
long timeo;
bool more;
int ret, copied;
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
/* this should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
return -EPIPE;
more = msg->msg_flags & MSG_MORE;
if (call->tx_total_len != -1) {
if (len > call->tx_total_len)
return -EMSGSIZE;
if (!more && len != call->tx_total_len)
return -EMSGSIZE;
}
skb = call->tx_pending;
call->tx_pending = NULL;
rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
copied = 0;
do {
/* Check to see if there's a ping ACK to reply to. */
if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
rxrpc_send_ack_packet(call, false);
if (!skb) {
size_t size, chunk, max, space;
_debug("alloc");
if (call->tx_top - call->tx_hard_ack >=
min_t(unsigned int, call->tx_winsize,
call->cong_cwnd + call->cong_extra)) {
ret = -EAGAIN;
if (msg->msg_flags & MSG_DONTWAIT)
goto maybe_error;
ret = rxrpc_wait_for_tx_window(rx, call,
&timeo);
if (ret < 0)
goto maybe_error;
}
max = RXRPC_JUMBO_DATALEN;
max -= call->conn->security_size;
max &= ~(call->conn->size_align - 1UL);
chunk = max;
if (chunk > msg_data_left(msg) && !more)
chunk = msg_data_left(msg);
space = chunk + call->conn->size_align;
space &= ~(call->conn->size_align - 1UL);
size = space + call->conn->security_size;
_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
/* create a buffer that we can retain until it's ACK'd */
skb = sock_alloc_send_skb(
sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
if (!skb)
goto maybe_error;
rxrpc_new_skb(skb, rxrpc_skb_tx_new);
_debug("ALLOC SEND %p", skb);
ASSERTCMP(skb->mark, ==, 0);
_debug("HS: %u", call->conn->security_size);
skb_reserve(skb, call->conn->security_size);
skb->len += call->conn->security_size;
sp = rxrpc_skb(skb);
sp->remain = chunk;
if (sp->remain > skb_tailroom(skb))
sp->remain = skb_tailroom(skb);
_net("skb: hr %d, tr %d, hl %d, rm %d",
skb_headroom(skb),
skb_tailroom(skb),
skb_headlen(skb),
sp->remain);
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
_debug("append");
sp = rxrpc_skb(skb);
/* append next segment of data to the current buffer */
if (msg_data_left(msg) > 0) {
int copy = skb_tailroom(skb);
ASSERTCMP(copy, >, 0);
if (copy > msg_data_left(msg))
copy = msg_data_left(msg);
if (copy > sp->remain)
copy = sp->remain;
_debug("add");
ret = skb_add_data(skb, &msg->msg_iter, copy);
_debug("added");
if (ret < 0)
goto efault;
sp->remain -= copy;
skb->mark += copy;
copied += copy;
if (call->tx_total_len != -1)
call->tx_total_len -= copy;
}
/* add the packet to the send queue if it's now full */
if (sp->remain <= 0 ||
(msg_data_left(msg) == 0 && !more)) {
struct rxrpc_connection *conn = call->conn;
uint32_t seq;
size_t pad;
/* pad out if we're using security */
if (conn->security_ix) {
pad = conn->security_size + skb->mark;
pad = conn->size_align - pad;
pad &= conn->size_align - 1;
_debug("pad %zu", pad);
if (pad)
skb_put_zero(skb, pad);
}
seq = call->tx_top + 1;
sp->hdr.seq = seq;
sp->hdr._rsvd = 0;
sp->hdr.flags = conn->out_clientflag;
if (msg_data_left(msg) == 0 && !more)
sp->hdr.flags |= RXRPC_LAST_PACKET;
else if (call->tx_top - call->tx_hard_ack <
call->tx_winsize)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
ret = conn->security->secure_packet(
call, skb, skb->mark, skb->head);
if (ret < 0)
goto out;
rxrpc_queue_packet(rx, call, skb,
!msg_data_left(msg) && !more,
notify_end_tx);
skb = NULL;
}
/* Check for the far side aborting the call or a network error
* occurring. If this happens, save any packet that was under
* construction so that in the case of a network error, the
* call can be retried or redirected.
*/
if (call->state == RXRPC_CALL_COMPLETE) {
ret = call->error;
goto out;
}
} while (msg_data_left(msg) > 0);
success:
ret = copied;
out:
call->tx_pending = skb;
_leave(" = %d", ret);
return ret;
maybe_error:
if (copied)
goto success;
goto out;
efault:
ret = -EFAULT;
goto out;
}
/*
* 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->user_call_ID = *(u32 *)CMSG_DATA(cmsg);
} else {
if (len != sizeof(unsigned long))
return -EINVAL;
p->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_ACCEPT:
if (p->command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
p->command = RXRPC_CMD_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->tx_total_len != -1 || len != sizeof(__s64))
return -EINVAL;
p->tx_total_len = *(__s64 *)CMSG_DATA(cmsg);
if (p->tx_total_len < 0)
return -EINVAL;
break;
default:
return -EINVAL;
}
}
if (!got_user_ID)
return -EINVAL;
if (p->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)
{
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->user_call_ID,
p->tx_total_len, GFP_KERNEL);
/* 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)
{
enum rxrpc_call_state state;
struct rxrpc_call *call;
int ret;
struct rxrpc_send_params p = {
.tx_total_len = -1,
.user_call_ID = 0,
.abort_code = 0,
.command = RXRPC_CMD_SEND_DATA,
.exclusive = false,
.upgrade = true,
};
_enter("");
ret = rxrpc_sendmsg_cmsg(msg, &p);
if (ret < 0)
goto error_release_sock;
if (p.command == RXRPC_CMD_ACCEPT) {
ret = -EINVAL;
if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
goto error_release_sock;
call = rxrpc_accept_call(rx, p.user_call_ID, NULL);
/* The socket is now unlocked. */
if (IS_ERR(call))
return PTR_ERR(call);
rxrpc_put_call(call, rxrpc_call_put);
return 0;
}
call = rxrpc_find_call_by_user_ID(rx, p.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. */
} else {
switch (READ_ONCE(call->state)) {
case RXRPC_CALL_UNINITIALISED:
case RXRPC_CALL_CLIENT_AWAIT_CONN:
case RXRPC_CALL_SERVER_PREALLOC:
case RXRPC_CALL_SERVER_SECURING:
case RXRPC_CALL_SERVER_ACCEPTING:
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.tx_total_len != -1) {
ret = -EINVAL;
if (call->tx_total_len != -1 ||
call->tx_pending ||
call->tx_top != 0)
goto error_put;
call->tx_total_len = p.tx_total_len;
}
}
state = READ_ONCE(call->state);
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, state, call->conn);
if (state >= RXRPC_CALL_COMPLETE) {
/* it's too late for this call */
ret = -ESHUTDOWN;
} else if (p.command == RXRPC_CMD_SEND_ABORT) {
ret = 0;
if (rxrpc_abort_call("CMD", call, 0, p.abort_code, -ECONNABORTED))
ret = rxrpc_send_abort_packet(call);
} else if (p.command != RXRPC_CMD_SEND_DATA) {
ret = -EINVAL;
} else if (rxrpc_is_client_call(call) &&
state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
/* request phase complete for this client call */
ret = -EPROTO;
} else if (rxrpc_is_service_call(call) &&
state != RXRPC_CALL_SERVER_ACK_REQUEST &&
state != RXRPC_CALL_SERVER_SEND_REPLY) {
/* Reply phase not begun or not complete for service call. */
ret = -EPROTO;
} else {
ret = rxrpc_send_data(rx, call, msg, len, NULL);
}
mutex_unlock(&call->user_mutex);
error_put:
rxrpc_put_call(call, rxrpc_call_put);
_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)
{
int ret;
_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
ASSERTCMP(msg->msg_name, ==, NULL);
ASSERTCMP(msg->msg_control, ==, NULL);
mutex_lock(&call->user_mutex);
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
switch (READ_ONCE(call->state)) {
case RXRPC_CALL_CLIENT_SEND_REQUEST:
case RXRPC_CALL_SERVER_ACK_REQUEST:
case RXRPC_CALL_SERVER_SEND_REPLY:
ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
notify_end_tx);
break;
case RXRPC_CALL_COMPLETE:
read_lock_bh(&call->state_lock);
ret = call->error;
read_unlock_bh(&call->state_lock);
break;
default:
/* Request phase complete for this client call */
trace_rxrpc_rx_eproto(call, 0, tracepoint_string("late_send"));
ret = -EPROTO;
break;
}
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: 3-char string indicating 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, const char *why)
{
bool aborted;
_enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
mutex_lock(&call->user_mutex);
aborted = rxrpc_abort_call(why, call, 0, abort_code, error);
if (aborted)
rxrpc_send_abort_packet(call);
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);