/* RxRPC recvmsg() implementation
*
* 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/skbuff.h>
#include <linux/export.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
/*
* receive a message from an RxRPC socket
* - we need to be careful about two or more threads calling recvmsg
* simultaneously
*/
int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
struct rxrpc_skb_priv *sp;
struct rxrpc_call *call = NULL, *continue_call = NULL;
struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
struct sk_buff *skb;
long timeo;
int copy, ret, ullen, offset, copied = 0;
u32 abort_code;
DEFINE_WAIT(wait);
_enter(",,,%zu,%d", len, flags);
if (flags & (MSG_OOB | MSG_TRUNC))
return -EOPNOTSUPP;
ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
msg->msg_flags |= MSG_MORE;
lock_sock(&rx->sk);
for (;;) {
/* return immediately if a client socket has no outstanding
* calls */
if (RB_EMPTY_ROOT(&rx->calls)) {
if (copied)
goto out;
if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
release_sock(&rx->sk);
if (continue_call)
rxrpc_put_call(continue_call,
rxrpc_call_put);
return -ENODATA;
}
}
/* get the next message on the Rx queue */
skb = skb_peek(&rx->sk.sk_receive_queue);
if (!skb) {
/* nothing remains on the queue */
if (copied &&
(flags & MSG_PEEK || timeo == 0))
goto out;
/* wait for a message to turn up */
release_sock(&rx->sk);
prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
TASK_INTERRUPTIBLE);
ret = sock_error(&rx->sk);
if (ret)
goto wait_error;
if (skb_queue_empty(&rx->sk.sk_receive_queue)) {
if (signal_pending(current))
goto wait_interrupted;
timeo = schedule_timeout(timeo);
}
finish_wait(sk_sleep(&rx->sk), &wait);
lock_sock(&rx->sk);
continue;
}
peek_next_packet:
rxrpc_see_skb(skb);
sp = rxrpc_skb(skb);
call = sp->call;
ASSERT(call != NULL);
rxrpc_see_call(call);
_debug("next pkt %s", rxrpc_pkts[sp->hdr.type]);
/* make sure we wait for the state to be updated in this call */
spin_lock_bh(&call->lock);
spin_unlock_bh(&call->lock);
if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
_debug("packet from released call");
if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
BUG();
rxrpc_free_skb(skb);
continue;
}
/* determine whether to continue last data receive */
if (continue_call) {
_debug("maybe cont");
if (call != continue_call ||
skb->mark != RXRPC_SKB_MARK_DATA) {
release_sock(&rx->sk);
rxrpc_put_call(continue_call, rxrpc_call_put);
_leave(" = %d [noncont]", copied);
return copied;
}
}
rxrpc_get_call(call, rxrpc_call_got);
/* copy the peer address and timestamp */
if (!continue_call) {
if (msg->msg_name) {
size_t len =
sizeof(call->conn->params.peer->srx);
memcpy(msg->msg_name,
&call->conn->params.peer->srx, len);
msg->msg_namelen = len;
}
sock_recv_timestamp(msg, &rx->sk, skb);
}
/* receive the message */
if (skb->mark != RXRPC_SKB_MARK_DATA)
goto receive_non_data_message;
_debug("recvmsg DATA #%u { %d, %d }",
sp->hdr.seq, skb->len, sp->offset);
if (!continue_call) {
/* only set the control data once per recvmsg() */
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
ullen, &call->user_call_ID);
if (ret < 0)
goto copy_error;
ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
}
ASSERTCMP(sp->hdr.seq, >=, call->rx_data_recv);
ASSERTCMP(sp->hdr.seq, <=, call->rx_data_recv + 1);
call->rx_data_recv = sp->hdr.seq;
ASSERTCMP(sp->hdr.seq, >, call->rx_data_eaten);
offset = sp->offset;
copy = skb->len - offset;
if (copy > len - copied)
copy = len - copied;
ret = skb_copy_datagram_msg(skb, offset, msg, copy);
if (ret < 0)
goto copy_error;
/* handle piecemeal consumption of data packets */
_debug("copied %d+%d", copy, copied);
offset += copy;
copied += copy;
if (!(flags & MSG_PEEK))
sp->offset = offset;
if (sp->offset < skb->len) {
_debug("buffer full");
ASSERTCMP(copied, ==, len);
break;
}
/* we transferred the whole data packet */
if (!(flags & MSG_PEEK))
rxrpc_kernel_data_consumed(call, skb);
if (sp->hdr.flags & RXRPC_LAST_PACKET) {
_debug("last");
if (rxrpc_conn_is_client(call->conn)) {
/* last byte of reply received */
ret = copied;
goto terminal_message;
}
/* last bit of request received */
if (!(flags & MSG_PEEK)) {
_debug("eat packet");
if (skb_dequeue(&rx->sk.sk_receive_queue) !=
skb)
BUG();
rxrpc_free_skb(skb);
}
msg->msg_flags &= ~MSG_MORE;
break;
}
/* move on to the next data message */
_debug("next");
if (!continue_call)
continue_call = sp->call;
else
rxrpc_put_call(call, rxrpc_call_put);
call = NULL;
if (flags & MSG_PEEK) {
_debug("peek next");
skb = skb->next;
if (skb == (struct sk_buff *) &rx->sk.sk_receive_queue)
break;
goto peek_next_packet;
}
_debug("eat packet");
if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
BUG();
rxrpc_free_skb(skb);
}
/* end of non-terminal data packet reception for the moment */
_debug("end rcv data");
out:
release_sock(&rx->sk);
if (call)
rxrpc_put_call(call, rxrpc_call_put);
if (continue_call)
rxrpc_put_call(continue_call, rxrpc_call_put);
_leave(" = %d [data]", copied);
return copied;
/* handle non-DATA messages such as aborts, incoming connections and
* final ACKs */
receive_non_data_message:
_debug("non-data");
if (skb->mark == RXRPC_SKB_MARK_NEW_CALL) {
_debug("RECV NEW CALL");
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &abort_code);
if (ret < 0)
goto copy_error;
if (!(flags & MSG_PEEK)) {
if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
BUG();
rxrpc_free_skb(skb);
}
goto out;
}
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
ullen, &call->user_call_ID);
if (ret < 0)
goto copy_error;
ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
switch (skb->mark) {
case RXRPC_SKB_MARK_DATA:
BUG();
case RXRPC_SKB_MARK_FINAL_ACK:
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
break;
case RXRPC_SKB_MARK_BUSY:
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
break;
case RXRPC_SKB_MARK_REMOTE_ABORT:
abort_code = call->abort_code;
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
break;
case RXRPC_SKB_MARK_LOCAL_ABORT:
abort_code = call->abort_code;
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
if (call->error) {
abort_code = call->error;
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
&abort_code);
}
break;
case RXRPC_SKB_MARK_NET_ERROR:
_debug("RECV NET ERROR %d", sp->error);
abort_code = sp->error;
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &abort_code);
break;
case RXRPC_SKB_MARK_LOCAL_ERROR:
_debug("RECV LOCAL ERROR %d", sp->error);
abort_code = sp->error;
ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
&abort_code);
break;
default:
pr_err("Unknown packet mark %u\n", skb->mark);
BUG();
break;
}
if (ret < 0)
goto copy_error;
terminal_message:
_debug("terminal");
msg->msg_flags &= ~MSG_MORE;
msg->msg_flags |= MSG_EOR;
if (!(flags & MSG_PEEK)) {
_net("free terminal skb %p", skb);
if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
BUG();
rxrpc_free_skb(skb);
rxrpc_release_call(rx, call);
}
release_sock(&rx->sk);
rxrpc_put_call(call, rxrpc_call_put);
if (continue_call)
rxrpc_put_call(continue_call, rxrpc_call_put);
_leave(" = %d", ret);
return ret;
copy_error:
_debug("copy error");
release_sock(&rx->sk);
rxrpc_put_call(call, rxrpc_call_put);
if (continue_call)
rxrpc_put_call(continue_call, rxrpc_call_put);
_leave(" = %d", ret);
return ret;
wait_interrupted:
ret = sock_intr_errno(timeo);
wait_error:
finish_wait(sk_sleep(&rx->sk), &wait);
if (continue_call)
rxrpc_put_call(continue_call, rxrpc_call_put);
if (copied)
copied = ret;
_leave(" = %d [waitfail %d]", copied, ret);
return copied;
}
/*
* Deliver messages to a call. This keeps processing packets until the buffer
* is filled and we find either more DATA (returns 0) or the end of the DATA
* (returns 1). If more packets are required, it returns -EAGAIN.
*
* TODO: Note that this is hacked in at the moment and will be replaced.
*/
static int temp_deliver_data(struct socket *sock, struct rxrpc_call *call,
struct iov_iter *iter, size_t size,
size_t *_offset)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
size_t remain;
int ret, copy;
_enter("%d", call->debug_id);
next:
local_bh_disable();
skb = skb_dequeue(&call->knlrecv_queue);
local_bh_enable();
if (!skb) {
if (test_bit(RXRPC_CALL_RX_NO_MORE, &call->flags))
return 1;
_leave(" = -EAGAIN [empty]");
return -EAGAIN;
}
sp = rxrpc_skb(skb);
_debug("dequeued %p %u/%zu", skb, sp->offset, size);
switch (skb->mark) {
case RXRPC_SKB_MARK_DATA:
remain = size - *_offset;
if (remain > 0) {
copy = skb->len - sp->offset;
if (copy > remain)
copy = remain;
ret = skb_copy_datagram_iter(skb, sp->offset, iter,
copy);
if (ret < 0)
goto requeue_and_leave;
/* handle piecemeal consumption of data packets */
sp->offset += copy;
*_offset += copy;
}
if (sp->offset < skb->len)
goto partially_used_skb;
/* We consumed the whole packet */
ASSERTCMP(sp->offset, ==, skb->len);
if (sp->hdr.flags & RXRPC_LAST_PACKET)
set_bit(RXRPC_CALL_RX_NO_MORE, &call->flags);
rxrpc_kernel_data_consumed(call, skb);
rxrpc_free_skb(skb);
goto next;
default:
rxrpc_free_skb(skb);
goto next;
}
partially_used_skb:
ASSERTCMP(*_offset, ==, size);
ret = 0;
requeue_and_leave:
skb_queue_head(&call->knlrecv_queue, skb);
return ret;
}
/**
* rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
* @sock: The socket that the call exists on
* @call: The call to send data through
* @buf: The buffer to receive into
* @size: The size of the buffer, including data already read
* @_offset: The running offset into the buffer.
* @want_more: True if more data is expected to be read
* @_abort: Where the abort code is stored if -ECONNABORTED is returned
*
* Allow a kernel service to receive data and pick up information about the
* state of a call. Returns 0 if got what was asked for and there's more
* available, 1 if we got what was asked for and we're at the end of the data
* and -EAGAIN if we need more data.
*
* Note that we may return -EAGAIN to drain empty packets at the end of the
* data, even if we've already copied over the requested data.
*
* This function adds the amount it transfers to *_offset, so this should be
* precleared as appropriate. Note that the amount remaining in the buffer is
* taken to be size - *_offset.
*
* *_abort should also be initialised to 0.
*/
int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
void *buf, size_t size, size_t *_offset,
bool want_more, u32 *_abort)
{
struct iov_iter iter;
struct kvec iov;
int ret;
_enter("{%d,%s},%zu,%d",
call->debug_id, rxrpc_call_states[call->state], size, want_more);
ASSERTCMP(*_offset, <=, size);
ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING);
iov.iov_base = buf + *_offset;
iov.iov_len = size - *_offset;
iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset);
lock_sock(sock->sk);
switch (call->state) {
case RXRPC_CALL_CLIENT_RECV_REPLY:
case RXRPC_CALL_SERVER_RECV_REQUEST:
case RXRPC_CALL_SERVER_ACK_REQUEST:
ret = temp_deliver_data(sock, call, &iter, size, _offset);
if (ret < 0)
goto out;
/* We can only reach here with a partially full buffer if we
* have reached the end of the data. We must otherwise have a
* full buffer or have been given -EAGAIN.
*/
if (ret == 1) {
if (*_offset < size)
goto short_data;
if (!want_more)
goto read_phase_complete;
ret = 0;
goto out;
}
if (!want_more)
goto excess_data;
goto out;
case RXRPC_CALL_COMPLETE:
goto call_complete;
default:
*_offset = 0;
ret = -EINPROGRESS;
goto out;
}
read_phase_complete:
ret = 1;
out:
release_sock(sock->sk);
_leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
return ret;
short_data:
ret = -EBADMSG;
goto out;
excess_data:
ret = -EMSGSIZE;
goto out;
call_complete:
*_abort = call->abort_code;
ret = call->error;
if (call->completion == RXRPC_CALL_SUCCEEDED) {
ret = 1;
if (size > 0)
ret = -ECONNRESET;
}
goto out;
}
EXPORT_SYMBOL(rxrpc_kernel_recv_data);
