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incubator-nuttx/net/tcp/tcp_sendfile.c

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/****************************************************************************
* net/tcp/tcp_sendfile.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/semaphore.h>
#include <nuttx/fs/fs.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/tcp.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "arp/arp.h"
#include "icmpv6/icmpv6.h"
#include "neighbor/neighbor.h"
#include "socket/socket.h"
#include "tcp/tcp.h"
#if defined(CONFIG_NET_SENDFILE) && defined(CONFIG_NET_TCP) && \
defined(NET_TCP_HAVE_STACK)
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure holds the state of the send operation until it can be
* operated upon from the driver poll event.
*/
struct sendfile_s
{
FAR struct tcp_conn_s *snd_conn; /* Connection associated with the socket */
FAR struct devif_callback_s *snd_cb; /* Reference to callback instance */
FAR struct file *snd_file; /* File structure of the input file */
sem_t snd_sem; /* Used to wake up the waiting thread */
off_t snd_foffset; /* Input file offset */
size_t snd_flen; /* File length */
ssize_t snd_sent; /* The number of bytes sent */
uint32_t snd_isn; /* Initial sequence number */
uint32_t snd_acked; /* The number of bytes acked */
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
uint32_t snd_prev_ack; /* The previous ACKed seq number */
#ifdef CONFIG_NET_TCP_WINDOW_SCALE
uint32_t snd_prev_wnd; /* The advertised window in the last
* incoming acknowledgment
*/
#else
uint16_t snd_prev_wnd;
#endif
int snd_dup_acks; /* Duplicate ACK counter */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sendfile_eventhandler
*
* Description:
* This function is called to perform the actual send operation when
* polled by the lower, device interfacing layer.
*
* Input Parameters:
* dev The structure of the network driver that caused the event
* pvpriv An instance of struct sendfile_s cast to void*
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked
*
****************************************************************************/
static uint16_t sendfile_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvpriv, uint16_t flags)
{
FAR struct sendfile_s *pstate = pvpriv;
FAR struct tcp_conn_s *conn;
int ret;
DEBUGASSERT(pstate != NULL);
/* Get the TCP connection pointer reliably from
* the corresponding TCP socket.
*/
conn = pstate->snd_conn;
DEBUGASSERT(conn != NULL);
/* The TCP socket is connected and, hence, should be bound to a device.
* Make sure that the polling device is the own that we are bound to.
*/
DEBUGASSERT(conn->dev != NULL);
if (dev != conn->dev)
{
return flags;
}
ninfo("flags: %04x acked: %" PRId32 " sent: %zd\n",
flags, pstate->snd_acked, pstate->snd_sent);
/* The TCP_ACKDATA, TCP_REXMIT and TCP_DISCONN_EVENTS flags are expected to
* appear here strictly one at a time, except for the FIN + ACK case.
*/
DEBUGASSERT((flags & TCP_ACKDATA) == 0 ||
(flags & TCP_REXMIT) == 0);
DEBUGASSERT((flags & TCP_DISCONN_EVENTS) == 0 ||
(flags & TCP_REXMIT) == 0);
/* If this packet contains an acknowledgement, then update the count of
* acknowledged bytes.
* This condition is located here for performance reasons
* (TCP_ACKDATA is the most frequent event).
*/
if ((flags & TCP_ACKDATA) != 0)
{
uint32_t ackno;
FAR struct tcp_hdr_s *tcp;
/* Get the offset address of the TCP header */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
if (IFF_IS_IPv6(dev->d_flags))
#endif
{
tcp = TCPIPv6BUF;
}
#endif /* CONFIG_NET_IPv6 */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
else
#endif
{
tcp = TCPIPv4BUF;
}
#endif /* CONFIG_NET_IPv4 */
/* The current acknowledgement number is the (relative) offset
* of the of the next byte needed by the receiver. The snd_isn is the
* offset of the first byte to send to the receiver. The difference
* is the number of bytes to be acknowledged.
*/
ackno = tcp_getsequence(tcp->ackno);
pstate->snd_acked = TCP_SEQ_SUB(ackno, pstate->snd_isn);
ninfo("ACK: acked=%" PRId32 " sent=%zd flen=%zu\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_flen);
/* Have all of the bytes in the buffer been sent and acknowledged? */
if (pstate->snd_acked >= pstate->snd_flen)
{
/* Yes. Then pstate->snd_flen should hold the number of bytes
* actually sent.
*/
goto end_wait;
}
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
/* Fast Retransmit (RFC 5681): an acknowledgment is considered a
* "duplicate" when (a) the receiver of the ACK has outstanding data,
* (b) the incoming acknowledgment carries no data, (c) the SYN and
* FIN bits are both off, (d) the acknowledgment number is equal to
* the greatest acknowledgment received on the given connection
* and (e) the advertised window in the incoming acknowledgment equals
* the advertised window in the last incoming acknowledgment.
*/
if (pstate->snd_acked < pstate->snd_sent &&
(flags & TCP_NEWDATA) == 0 &&
(tcp->flags & (TCP_SYN | TCP_FIN)) == 0 &&
ackno == pstate->snd_prev_ack &&
conn->snd_wnd == pstate->snd_prev_wnd)
{
if (++pstate->snd_dup_acks >= TCP_FAST_RETRANSMISSION_THRESH)
{
flags |= TCP_REXMIT;
pstate->snd_dup_acks = 0;
}
}
else
{
pstate->snd_dup_acks = 0;
}
pstate->snd_prev_ack = ackno;
pstate->snd_prev_wnd = conn->snd_wnd;
#endif
}
/* Check if we are being asked to retransmit data.
* This condition is located here (after TCP_ACKDATA and before
* TCP_DISCONN_EVENTS) for performance reasons.
*/
if ((flags & TCP_REXMIT) != 0)
{
uint32_t sndlen;
nwarn("WARNING: TCP_REXMIT\n");
/* According to RFC 6298 (5.4), retransmit the earliest segment
* that has not been acknowledged by the TCP receiver.
*/
/* Reconstruct the length of the earliest segment to be retransmitted */
sndlen = pstate->snd_flen - pstate->snd_acked;
if (sndlen > conn->mss)
{
sndlen = conn->mss;
}
conn->rexmit_seq = pstate->snd_isn + pstate->snd_acked;
/* Then set-up to send that amount of data. (this won't actually
* happen until the polling cycle completes).
*/
ret = file_seek(pstate->snd_file,
pstate->snd_foffset + pstate->snd_acked, SEEK_SET);
if (ret < 0)
{
nerr("ERROR: Failed to lseek: %d\n", ret);
pstate->snd_sent = ret;
goto end_wait;
}
ret = file_read(pstate->snd_file, dev->d_appdata, sndlen);
if (ret < 0)
{
nerr("ERROR: Failed to read from input file: %d\n", (int)ret);
pstate->snd_sent = ret;
goto end_wait;
}
dev->d_sndlen = sndlen;
/* Continue waiting */
return flags;
}
/* Check for a loss of connection.
* This condition is located here after both the TCP_ACKDATA and TCP_REXMIT
* because TCP_DISCONN_EVENTS is the least frequent event.
*/
else if ((flags & TCP_DISCONN_EVENTS) != 0)
{
nwarn("WARNING: Lost connection\n");
/* We could get here recursively through the callback actions of
* tcp_lost_connection(). So don't repeat that action if we have
* already been disconnected.
*/
if (_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* Report not connected */
tcp_lost_connection(conn, pstate->snd_cb, flags);
}
/* Report not connected */
pstate->snd_sent = -ENOTCONN;
goto end_wait;
}
/* We get here if (1) not all of the data has been ACKed, (2) we have been
* asked to retransmit data, (3) the connection is still healthy, and (4)
* the outgoing packet is available for our use. In this case, we are
* now free to send more data to receiver -- UNLESS the buffer contains
* unprocessing incoming data. In that event, we will have to wait for the
* next polling cycle.
*/
if ((flags & TCP_NEWDATA) == 0 && pstate->snd_sent < pstate->snd_flen)
{
/* Get the amount of data that we can send in the next packet */
uint32_t sndlen = pstate->snd_flen - pstate->snd_sent;
if (sndlen > conn->mss)
{
sndlen = conn->mss;
}
/* Check if we have "space" in the window */
if ((pstate->snd_sent - pstate->snd_acked + sndlen) < conn->snd_wnd)
{
/* Then set-up to send that amount of data. (this won't actually
* happen until the polling cycle completes).
*/
ret = file_seek(pstate->snd_file,
pstate->snd_foffset + pstate->snd_sent, SEEK_SET);
if (ret < 0)
{
nerr("ERROR: Failed to lseek: %d\n", ret);
pstate->snd_sent = ret;
goto end_wait;
}
ret = file_read(pstate->snd_file, dev->d_appdata, sndlen);
if (ret < 0)
{
nerr("ERROR: Failed to read from input file: %d\n", (int)ret);
pstate->snd_sent = ret;
goto end_wait;
}
dev->d_sndlen = sndlen;
/* Update the amount of data sent (but not necessarily ACKed) */
pstate->snd_sent += sndlen;
ninfo("pid: %d SEND: acked=%" PRId32 " sent=%zd flen=%zu\n",
getpid(),
pstate->snd_acked, pstate->snd_sent, pstate->snd_flen);
}
else
{
nwarn("WARNING: Window full, wait for ack\n");
}
}
/* Continue waiting */
return flags;
end_wait:
/* Do not allow any further callbacks */
DEBUGASSERT(pstate->snd_cb != NULL);
pstate->snd_cb->flags = 0;
pstate->snd_cb->priv = NULL;
pstate->snd_cb->event = NULL;
/* There are no outstanding, unacknowledged bytes */
conn->tx_unacked = 0;
/* Wake up the waiting thread */
nxsem_post(&pstate->snd_sem);
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_sendfile
*
* Description:
* The tcp_sendfile() call may be used only when the INET socket is in a
* connected state (so that the intended recipient is known).
*
* Input Parameters:
* psock An instance of the internal socket structure.
* buf Data to send
* len Length of data to send
* flags Send flags
*
* Returned Value:
* On success, returns the number of characters sent. On error,
* a negated errno value is returned. See sendfile() for a list
* appropriate error return values.
*
****************************************************************************/
ssize_t tcp_sendfile(FAR struct socket *psock, FAR struct file *infile,
FAR off_t *offset, size_t count)
{
FAR struct tcp_conn_s *conn;
struct sendfile_s state;
off_t startpos;
int ret;
conn = psock->s_conn;
DEBUGASSERT(conn != NULL);
/* If this is an un-connected socket, then return ENOTCONN */
if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(conn->sconn.s_flags))
{
nerr("ERROR: Not connected\n");
return -ENOTCONN;
}
/* Make sure that we have the IP address mapping */
#if defined(CONFIG_NET_ARP_SEND) || defined(CONFIG_NET_ICMPv6_NEIGHBOR)
#ifdef CONFIG_NET_ARP_SEND
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
if (psock->s_domain == PF_INET)
#endif
{
/* Make sure that the IP address mapping is in the ARP table */
ret = arp_send(conn->u.ipv4.raddr);
}
#endif /* CONFIG_NET_ARP_SEND */
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
#ifdef CONFIG_NET_ARP_SEND
else
#endif
{
/* Make sure that the IP address mapping is in the Neighbor Table */
ret = icmpv6_neighbor(conn->u.ipv6.raddr);
}
#endif /* CONFIG_NET_ICMPv6_NEIGHBOR */
/* Did we successfully get the address mapping? */
if (ret < 0)
{
nerr("ERROR: Not reachable\n");
return -ENETUNREACH;
}
#endif /* CONFIG_NET_ARP_SEND || CONFIG_NET_ICMPv6_NEIGHBOR */
/* Get the current file position. */
startpos = file_seek(infile, 0, SEEK_CUR);
if (startpos < 0)
{
return startpos;
}
/* Initialize the state structure. This is done with the network
* locked because we don't want anything to happen until we are
* ready.
*/
net_lock();
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
conn->sendfile = true;
#endif
memset(&state, 0, sizeof(struct sendfile_s));
nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */
state.snd_conn = conn; /* Tcp conn to use */
state.snd_foffset = offset ? *offset : startpos; /* Input file offset */
state.snd_flen = count; /* Number of bytes to send */
state.snd_file = infile; /* File to read from */
/* Allocate resources to receive a callback */
state.snd_cb = tcp_callback_alloc(conn);
if (state.snd_cb == NULL)
{
nerr("ERROR: Failed to allocate callback\n");
ret = -ENOMEM;
goto errout_locked;
}
/* Get the initial sequence number that will be used */
state.snd_isn = tcp_getsequence(conn->sndseq);
/* There is no outstanding, unacknowledged data after this
* initial sequence number.
*/
conn->tx_unacked = 0;
/* Set up the callback in the connection */
state.snd_cb->flags = (TCP_ACKDATA | TCP_REXMIT | TCP_POLL |
TCP_DISCONN_EVENTS);
state.snd_cb->priv = (FAR void *)&state;
state.snd_cb->event = sendfile_eventhandler;
/* Notify the device driver of the availability of TX data */
tcp_send_txnotify(psock, conn);
for (; ; )
{
uint32_t acked = state.snd_acked;
ret = net_sem_timedwait_uninterruptible(
&state.snd_sem, _SO_TIMEOUT(conn->sconn.s_sndtimeo));
if (ret != -ETIMEDOUT || acked == state.snd_acked)
{
if (ret == -ETIMEDOUT)
{
ret = -EAGAIN;
}
break; /* Successful completion or timeout without any progress */
}
}
tcp_callback_free(conn, state.snd_cb);
errout_locked:
nxsem_destroy(&state.snd_sem);
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
conn->sendfile = false;
#endif
net_unlock();
/* Return the current file position */
if (offset)
{
/* Use lseek to get the current file position */
off_t curpos = file_seek(infile, 0, SEEK_CUR);
if (curpos < 0)
{
return curpos;
}
/* Return the current file position */
*offset = curpos;
/* Use lseek again to restore the original file position */
startpos = file_seek(infile, startpos, SEEK_SET);
if (startpos < 0)
{
return startpos;
}
}
if (ret < 0)
{
return ret;
}
else
{
return state.snd_sent;
}
}
#endif /* CONFIG_NET_SENDFILE && CONFIG_NET_TCP && NET_TCP_HAVE_STACK */
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