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nuttx/net/net_send_buffered.c

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/****************************************************************************
* net/net_send_buffered.c
*
* Copyright (C) 2007-2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
* Jason Jiang <jasonj@live.cn>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) && \
defined(CONFIG_NET_TCP_WRITE_BUFFERS)
#if defined(CONFIG_DEBUG) && defined(CONFIG_NET_TCP_WRBUFFER_DEBUG)
/* Force debug output (from this file only) */
# undef CONFIG_DEBUG_NET
# define CONFIG_DEBUG_NET 1
#endif
#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/clock.h>
#include <nuttx/net/arp.h>
#include <nuttx/net/iob.h>
#include <nuttx/net/uip/uip-arch.h>
#include "net_internal.h"
#include "tcp/tcp.h"
#include "uip/uip_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define TCPBUF ((struct uip_tcpip_hdr *)&dev->d_buf[UIP_LLH_LEN])
/* Debug */
#ifdef CONFIG_NET_TCP_WRBUFFER_DUMP
# define BUF_DUMP(msg,buf,len) lib_dumpbuffer(msg,buf,len)
#else
# define BUF_DUMP(msg,buf,len)
# undef WRB_DUMP
# define WRB_DUMP(msg,wrb,len)
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Function: send_insert_seqment
*
* Description:
* Insert a new segment in a write buffer queue, keep the segment queue in
* ascending order of sequence number.
*
* Parameters:
* wrb The segment to be inserted
* q The write buffer queue in which to insert the segment
*
* Returned Value:
* None
*
* Assumptions:
* Running at the interrupt level
*
****************************************************************************/
static void send_insert_seqment(FAR struct tcp_wrbuffer_s *wrb,
FAR sq_queue_t *q)
{
sq_entry_t *entry = (sq_entry_t*)wrb;
sq_entry_t *insert = NULL;
sq_entry_t *itr;
for (itr = sq_peek(q); itr; itr = sq_next(itr))
{
FAR struct tcp_wrbuffer_s *wrb0 = (FAR struct tcp_wrbuffer_s*)itr;
if (WRB_SEQNO(wrb0) < WRB_SEQNO(wrb))
{
insert = itr;
}
else
{
break;
}
}
if (insert)
{
sq_addafter(insert, entry, q);
}
else
{
sq_addfirst(entry, q);
}
}
/****************************************************************************
* Function: lost_connection
*
* Description:
* The TCP connection has been lost. Free all write buffers.
*
* Parameters:
* psock The socket structure
* conn The connection structure associated with the socket
*
* Returned Value:
* None
*
****************************************************************************/
static inline void lost_connection(FAR struct socket *psock,
FAR struct uip_conn *conn)
{
FAR sq_entry_t *entry;
FAR sq_entry_t *next;
/* Do not allow any further callbacks */
psock->s_sndcb->flags = 0;
psock->s_sndcb->event = NULL;
/* Free all queued write buffers */
for (entry = sq_peek(&conn->unacked_q); entry; entry = next)
{
next = sq_next(entry);
tcp_wrbuffer_release((FAR struct tcp_wrbuffer_s *)entry);
}
for (entry = sq_peek(&conn->write_q); entry; entry = next)
{
next = sq_next(entry);
tcp_wrbuffer_release((FAR struct tcp_wrbuffer_s *)entry);
}
/* Reset write buffering variables */
sq_init(&conn->unacked_q);
sq_init(&conn->write_q);
conn->sent = 0;
}
/****************************************************************************
* Function: send_interrupt
*
* Description:
* This function is called from the interrupt level to perform the actual
* send operation when polled by the uIP layer.
*
* Parameters:
* dev The structure of the network driver that caused the interrupt
* conn The connection structure associated with the socket
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* Running at the interrupt level
*
****************************************************************************/
static uint16_t send_interrupt(FAR struct uip_driver_s *dev, FAR void *pvconn,
FAR void *pvpriv, uint16_t flags)
{
FAR struct uip_conn *conn = (FAR struct uip_conn *)pvconn;
FAR struct socket *psock = (FAR struct socket *)pvpriv;
nllvdbg("flags: %04x\n", flags);
/* If this packet contains an acknowledgement, then update the count of
* acknowledged bytes.
*/
if ((flags & UIP_ACKDATA) != 0)
{
FAR struct tcp_wrbuffer_s *wrb;
FAR sq_entry_t *entry;
FAR sq_entry_t *next;
uint32_t ackno;
ackno = uip_tcpgetsequence(TCPBUF->ackno);
nllvdbg("ACK: ackno=%u flags=%04x\n", ackno, flags);
/* Look at every write buffer in the unacked_q. The unacked_q
* holds write buffers that have been entirely sent, but which
* have not yet been ACKed.
*/
for (entry = sq_peek(&conn->unacked_q); entry; entry = next)
{
uint32_t lastseq;
/* Check of some or all of this write buffer has been ACKed. */
next = sq_next(entry);
wrb = (FAR struct tcp_wrbuffer_s*)entry;
/* If the ACKed sequence number is greater than the start
* sequence number of the write buffer, then some or all of
* the write buffer has been ACKed.
*/
if (ackno > WRB_SEQNO(wrb))
{
/* Get the sequence number at the end of the data */
lastseq = WRB_SEQNO(wrb) + WRB_PKTLEN(wrb);
nllvdbg("ACK: wrb=%p seqno=%u lastseq=%u pktlen=%u ackno=%u\n",
wrb, WRB_SEQNO(wrb), lastseq, WRB_PKTLEN(wrb), ackno);
/* Has the entire buffer been ACKed? */
if (ackno >= lastseq)
{
nllvdbg("ACK: wrb=%p Freeing write buffer\n", wrb);
/* Yes... Remove the write buffer from ACK waiting queue */
sq_rem(entry, &conn->unacked_q);
/* And return the write buffer to the pool of free buffers */
tcp_wrbuffer_release(wrb);
}
else
{
unsigned int trimlen;
/* No, then just trim the ACKed bytes from the beginning
* of the write buffer. This will free up some I/O buffers
* that can be reused while are still sending the last
* buffers in the chain.
*/
trimlen = ackno - WRB_SEQNO(wrb);
nllvdbg("ACK: wrb=%p trim %u bytes\n", wrb, trimlen);
WRB_TRIM(wrb, trimlen);
/* Set the new sequence number for what remains */
WRB_SEQNO(wrb) = ackno;
nllvdbg("ACK: wrb=%p seqno=%u pktlen=%u\n",
wrb, WRB_SEQNO(wrb), WRB_PKTLEN(wrb));
}
}
}
/* A special case is the head of the write_q which may be partially
* sent and so can still have un-ACKed bytes that could get ACKed
* before the entire write buffer has even been sent.
*/
wrb = (FAR struct tcp_wrbuffer_s*)sq_peek(&conn->write_q);
if (wrb && WRB_SENT(wrb) > 0 && ackno > WRB_SEQNO(wrb))
{
uint32_t nacked;
/* Number of bytes that were ACKed */
nacked = ackno - WRB_SEQNO(wrb);
if (nacked > WRB_SENT(wrb))
{
/* More data has been ACKed then we have sent? */
nacked = WRB_SENT(wrb);
}
nllvdbg("ACK: wrb=%p seqno=%u nacked=%u sent=%u ackno=%u\n",
wrb, WRB_SEQNO(wrb), nacked, WRB_SENT(wrb), ackno);
/* Trim the ACKed bytes from the beginning of the write buffer. */
WRB_TRIM(wrb, nacked);
WRB_SEQNO(wrb) = ackno;
WRB_SENT(wrb) -= nacked;
nllvdbg("ACK: wrb=%p seqno=%u pktlen=%u sent=%u\n",
wrb, WRB_SEQNO(wrb), WRB_PKTLEN(wrb), WRB_SENT(wrb));
}
}
/* Check for a loss of connection */
else if ((flags & (UIP_CLOSE | UIP_ABORT | UIP_TIMEDOUT)) != 0)
{
nllvdbg("Lost connection: %04x\n", flags);
/* Report not connected */
net_lostconnection(psock, flags);
/* Free write buffers and terminate polling */
lost_connection(psock, conn);
return flags;
}
/* Check if we are being asked to retransmit data */
else if ((flags & UIP_REXMIT) != 0)
{
FAR struct tcp_wrbuffer_s *wrb;
FAR sq_entry_t *entry;
nllvdbg("REXMIT: %04x\n", flags);
/* If there is a partially sent write buffer at the head of the
* write_q? Has anything been sent from that write buffer?
*/
wrb = (FAR struct tcp_wrbuffer_s *)sq_peek(&conn->write_q);
nllvdbg("REXMIT: wrb=%p sent=%u\n", wrb, wrb ? WRB_SENT(wrb) : 0);
if (wrb != NULL && WRB_SENT(wrb) > 0)
{
FAR struct tcp_wrbuffer_s *tmp;
uint16_t sent;
/* Yes.. Reset the number of bytes sent sent from the write buffer */
sent = WRB_SENT(wrb);
if (conn->unacked > sent)
{
conn->unacked -= sent;
}
else
{
conn->unacked = 0;
}
if (conn->sent > sent)
{
conn->sent -= sent;
}
else
{
conn->sent = 0;
}
WRB_SENT(wrb) = 0;
nllvdbg("REXMIT: wrb=%p sent=%u, conn unacked=%d sent=%d\n",
wrb, WRB_SENT(wrb), conn->unacked, conn->sent);
/* Increment the retransmit count on this write buffer. */
if (++WRB_NRTX(wrb) >= UIP_MAXRTX)
{
nlldbg("Expiring wrb=%p nrtx=%u\n", wrb, WRB_NRTX(wrb));
/* The maximum retry count as been exhausted. Remove the write
* buffer at the head of the queue.
*/
tmp = (FAR struct tcp_wrbuffer_s *)sq_remfirst(&conn->write_q);
DEBUGASSERT(tmp == wrb);
UNUSED(wrb);
/* And return the write buffer to the free list */
tcp_wrbuffer_release(wrb);
/* NOTE expired is different from un-ACKed, it is designed to
* represent the number of segments that have been sent,
* retransmitted, and un-ACKed, if expired is not zero, the
* connection will be closed.
*
* field expired can only be updated at UIP_ESTABLISHED state
*/
conn->expired++;
}
}
/* Move all segments that have been sent but not ACKed to the write
* queue again note, the un-ACKed segments are put at the head of the
* write_q so they can be resent as soon as possible.
*/
while ((entry = sq_remlast(&conn->unacked_q)) != NULL)
{
wrb = (FAR struct tcp_wrbuffer_s*)entry;
uint16_t sent;
/* Reset the number of bytes sent sent from the write buffer */
sent = WRB_SENT(wrb);
if (conn->unacked > sent)
{
conn->unacked -= sent;
}
else
{
conn->unacked = 0;
}
if (conn->sent > sent)
{
conn->sent -= sent;
}
else
{
conn->sent = 0;
}
WRB_SENT(wrb) = 0;
nllvdbg("REXMIT: wrb=%p sent=%u, conn unacked=%d sent=%d\n",
wrb, WRB_SENT(wrb), conn->unacked, conn->sent);
/* Free any write buffers that have exceed the retry count */
if (++WRB_NRTX(wrb) >= UIP_MAXRTX)
{
nlldbg("Expiring wrb=%p nrtx=%u\n", wrb, WRB_NRTX(wrb));
/* Return the write buffer to the free list */
tcp_wrbuffer_release(wrb);
/* NOTE expired is different from un-ACKed, it is designed to
* represent the number of segments that have been sent,
* retransmitted, and un-ACKed, if expired is not zero, the
* connection will be closed.
*
* field expired can only be updated at UIP_ESTABLISHED state
*/
conn->expired++;
continue;
}
else
{
/* Insert the write buffer into the write_q (in sequence
* number order). The retransmission will occur below
* when the write buffer with the lowest sequenc number
* is pulled from the write_q again.
*/
nllvdbg("REXMIT: Moving wrb=%p nrtx=%u\n", wrb, WRB_NRTX(wrb));
send_insert_seqment(wrb, &conn->write_q);
}
}
}
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto interrupt serving a different thread).
*/
if (dev->d_sndlen > 0)
{
/* Another thread has beat us sending data, wait for the next poll */
return flags;
}
/* 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
* unprocessed incoming data. In that event, we will have to wait for the
* next polling cycle.
*/
if ((conn->tcpstateflags & UIP_ESTABLISHED) &&
(flags & (UIP_POLL | UIP_REXMIT)) &&
!(sq_empty(&conn->write_q)))
{
/* Check if the destination IP address is in the ARP table. If not,
* then the send won't actually make it out... it will be replaced with
* an ARP request.
*
* NOTE 1: This could be an expensive check if there are a lot of
* entries in the ARP table.
*
* NOTE 2: If we are actually harvesting IP addresses on incoming IP
* packets, then this check should not be necessary; the MAC mapping
* should already be in the ARP table.
*/
#if defined(CONFIG_NET_ETHERNET) && !defined(CONFIG_NET_ARP_IPIN)
if (arp_find(conn->ripaddr) != NULL)
#endif
{
FAR struct tcp_wrbuffer_s *wrb;
size_t sndlen;
/* Peek at the head of the write queue (but don't remove anything
* from the write queue yet). We know from the above test that
* the write_q is not empty.
*/
wrb = (FAR struct tcp_wrbuffer_s *)sq_peek(&conn->write_q);
DEBUGASSERT(wrb);
/* Get the amount of data that we can send in the next packet.
* We will send either the remaining data in the buffer I/O
* buffer chain, or as much as will fit given the MSS and current
* window size.
*/
sndlen = WRB_PKTLEN(wrb) - WRB_SENT(wrb);
if (sndlen > uip_mss(conn))
{
sndlen = uip_mss(conn);
}
if (sndlen > conn->winsize)
{
sndlen = conn->winsize;
}
nllvdbg("SEND: wrb=%p pktlen=%u sent=%u sndlen=%u\n",
wrb, WRB_PKTLEN(wrb), WRB_SENT(wrb), sndlen);
/* Is this the first we have tried to send from this
* write buffer?
*/
if (WRB_SENT(wrb) == 0)
{
/* Yes.. Set the sequence number for this segment. If
* we are retransmitting, then the sequence number will
* already be set for this write buffer.
*/
if (WRB_SEQNO(wrb) == (unsigned)-1)
{
WRB_SEQNO(wrb) = conn->isn + conn->sent;
}
/* The TCP stack updates sndseq on receipt of ACK *before*
* this function is called. In that case sndseq will point
* to the next unacknowledged byte (which might have already
* been sent). We will overwrite the value of sndseq here
* before the packet is sent.
*/
uip_tcpsetsequence(conn->sndseq, WRB_SEQNO(wrb));
}
/* Then set-up to send that amount of data with the offset
* corresponding to the amount of data already sent. (this
* won't actually happen until the polling cycle completes).
*/
uip_iobsend(dev, WRB_IOB(wrb), sndlen, WRB_SENT(wrb));
/* Remember how much data we send out now so that we know
* when everything has been acknowledged. Just increment
* the amount of data sent. This will be needed in
* sequence number calculations.
*/
conn->unacked += sndlen;
conn->sent += sndlen;
nllvdbg("SEND: wrb=%p nrtx=%u unacked=%u sent=%u\n",
wrb, WRB_NRTX(wrb), conn->unacked, conn->sent);
/* Increment the count of bytes sent from this write buffer */
WRB_SENT(wrb) += sndlen;
nllvdbg("SEND: wrb=%p sent=%u pktlen=%u\n",
wrb, WRB_SENT(wrb), WRB_PKTLEN(wrb));
/* Remove the write buffer from the write queue if the
* last of the data has been sent from the buffer.
*/
DEBUGASSERT(WRB_SENT(wrb) <= WRB_PKTLEN(wrb));
if (WRB_SENT(wrb) >= WRB_PKTLEN(wrb))
{
FAR struct tcp_wrbuffer_s *tmp;
nllvdbg("ACK: wrb=%p Move to unacked_q\n", wrb);
tmp = (FAR struct tcp_wrbuffer_s *)sq_remfirst(&conn->write_q);
DEBUGASSERT(tmp == wrb);
UNUSED(tmp);
/* Put the I/O buffer chain in the un-acked queue; the
* segment is waiting for ACK again
*/
send_insert_seqment(wrb, &conn->unacked_q);
}
/* Only one data can be sent by low level driver at once,
* tell the caller stop polling the other connection.
*/
flags &= ~UIP_POLL;
}
}
/* Continue waiting */
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: psock_send
*
* Description:
* The send() call may be used only when the socket is in a connected state
* (so that the intended recipient is known). The only difference between
* send() and write() is the presence of flags. With zero flags parameter,
* send() is equivalent to write(). Also, send(sockfd,buf,len,flags) is
* equivalent to sendto(sockfd,buf,len,flags,NULL,0).
*
* 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,
* -1 is returned, and errno is set appropriately:
*
* EAGAIN or EWOULDBLOCK
* The socket is marked non-blocking and the requested operation
* would block.
* EBADF
* An invalid descriptor was specified.
* ECONNRESET
* Connection reset by peer.
* EDESTADDRREQ
* The socket is not connection-mode, and no peer address is set.
* EFAULT
* An invalid user space address was specified for a parameter.
* EINTR
* A signal occurred before any data was transmitted.
* EINVAL
* Invalid argument passed.
* EISCONN
* The connection-mode socket was connected already but a recipient
* was specified. (Now either this error is returned, or the recipient
* specification is ignored.)
* EMSGSIZE
* The socket type requires that message be sent atomically, and the
* size of the message to be sent made this impossible.
* ENOBUFS
* The output queue for a network interface was full. This generally
* indicates that the interface has stopped sending, but may be
* caused by transient congestion.
* ENOMEM
* No memory available.
* ENOTCONN
* The socket is not connected, and no target has been given.
* ENOTSOCK
* The argument s is not a socket.
* EOPNOTSUPP
* Some bit in the flags argument is inappropriate for the socket
* type.
* EPIPE
* The local end has been shut down on a connection oriented socket.
* In this case the process will also receive a SIGPIPE unless
* MSG_NOSIGNAL is set.
*
* Assumptions:
*
****************************************************************************/
ssize_t psock_send(FAR struct socket *psock, FAR const void *buf, size_t len,
int flags)
{
uip_lock_t save;
ssize_t result = 0;
int err;
int ret = OK;
if (!psock || psock->s_crefs <= 0)
{
err = EBADF;
goto errout;
}
if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(psock->s_flags))
{
err = ENOTCONN;
goto errout;
}
/* Dump the incoming buffer */
BUF_DUMP("psock_send", buf, len);
/* Set the socket state to sending */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
save = uip_lock();
if (len > 0)
{
struct uip_conn *conn = (struct uip_conn*)psock->s_conn;
/* Allocate resources to receive a callback */
if (!psock->s_sndcb)
{
psock->s_sndcb = uip_tcpcallbackalloc(conn);
}
/* Test if the callback has been allocated */
if (!psock->s_sndcb)
{
/* A buffer allocation error occurred */
ndbg("ERROR: Failed to allocate callback\n");
result = -ENOMEM;
}
else
{
FAR struct tcp_wrbuffer_s *wrb;
/* Set up the callback in the connection */
psock->s_sndcb->flags = (UIP_ACKDATA | UIP_REXMIT |UIP_POLL | \
UIP_CLOSE | UIP_ABORT | UIP_TIMEDOUT);
psock->s_sndcb->priv = (void*)psock;
psock->s_sndcb->event = send_interrupt;
/* Allocate an write buffer */
wrb = tcp_wrbuffer_alloc();
if (wrb)
{
/* Initialize the write buffer */
WRB_SEQNO(wrb) = (unsigned)-1;
WRB_NRTX(wrb) = 0;
WRB_COPYIN(wrb, (FAR uint8_t *)buf, len);
/* Dump I/O buffer chain */
WRB_DUMP("I/O buffer chain", wrb, WRB_PKTLEN(wrb));
/* send_interrupt() will send data in FIFO order from the
* conn->write_q
*/
sq_addlast(&wrb->wb_node, &conn->write_q);
nvdbg("Queued WRB=%p pktlen=%u write_q(%p,%p)\n",
wrb, WRB_PKTLEN(wrb),
conn->write_q.head, conn->write_q.tail);
/* Notify the device driver of the availability of TX data */
netdev_txnotify(conn->ripaddr);
result = len;
}
/* A buffer allocation error occurred */
else
{
ndbg("ERROR: Failed to allocate write buffer\n");
result = -ENOMEM;
}
}
}
uip_unlock(save);
/* Set the socket state to idle */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
/* Check for a errors. Errors are signaled by negative errno values
* for the send length
*/
if (result < 0)
{
err = result;
goto errout;
}
/* If uip_lockedwait failed, then we were probably reawakened by a signal.
* In this case, uip_lockedwait will have set errno appropriately.
*/
if (ret < 0)
{
err = -ret;
goto errout;
}
/* Return the number of bytes actually sent */
return result;
errout:
set_errno(err);
return ERROR;
}
#endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCP_WRITE_BUFFERS */
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