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incubator-nuttx/net/tcp/tcp_send_buffered.c

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/****************************************************************************
* net/tcp/tcp_send_buffered.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>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) && \
defined(CONFIG_NET_TCP_WRITE_BUFFERS)
#if defined(CONFIG_DEBUG_FEATURES) && 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 <inttypes.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/net/net.h>
#include <nuttx/mm/iob.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/tcp.h>
#include <nuttx/net/net.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "socket/socket.h"
#include "inet/inet.h"
#include "arp/arp.h"
#include "icmpv6/icmpv6.h"
#include "neighbor/neighbor.h"
#include "route/route.h"
#include "utils/utils.h"
#include "tcp/tcp.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* If both IPv4 and IPv6 support are both enabled, then we will need to build
* in some additional domain selection support.
*/
#if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6)
# define NEED_IPDOMAIN_SUPPORT 1
#endif
/* 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 TCP_WBDUMP
# define TCP_WBDUMP(msg,wrb,len,offset)
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: psock_insert_segment
*
* Description:
* Insert a new segment in a write buffer queue, keep the segment queue in
* ascending order of sequence number.
*
* Input Parameters:
* wrb The segment to be inserted
* q The write buffer queue in which to insert the segment
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked
*
****************************************************************************/
static void psock_insert_segment(FAR struct tcp_wrbuffer_s *wrb,
FAR sq_queue_t *q)
{
FAR sq_entry_t *entry = (FAR sq_entry_t *)wrb;
FAR sq_entry_t *insert = NULL;
FAR 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 (TCP_WBSEQNO(wrb0) < TCP_WBSEQNO(wrb))
{
insert = itr;
}
else
{
break;
}
}
if (insert)
{
sq_addafter(insert, entry, q);
}
else
{
sq_addfirst(entry, q);
}
}
/****************************************************************************
* Name: psock_writebuffer_notify
*
* Description:
* The TCP connection has been lost. Free all write buffers.
*
* Input Parameters:
* psock The socket structure
* conn The connection structure associated with the socket
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_NET_TCP_NOTIFIER
static void psock_writebuffer_notify(FAR struct tcp_conn_s *conn)
{
/* Check if all write buffers have been sent and ACKed */
if (sq_empty(&conn->write_q) && sq_empty(&conn->unacked_q))
{
/* Notify any waiters that the write buffers have been drained. */
tcp_writebuffer_signal(conn);
}
}
#else
# define psock_writebuffer_notify(conn)
#endif
static void retransmit_segment(FAR struct tcp_conn_s *conn,
FAR struct tcp_wrbuffer_s *wrb)
{
uint16_t sent;
/* Reset the number of bytes sent sent from the write buffer */
sent = TCP_WBSENT(wrb);
if (conn->tx_unacked > sent)
{
conn->tx_unacked -= sent;
}
else
{
conn->tx_unacked = 0;
}
if (conn->sent > sent)
{
conn->sent -= sent;
}
else
{
conn->sent = 0;
}
TCP_WBSENT(wrb) = 0;
ninfo("REXMIT: wrb=%p sent=%u, "
"conn tx_unacked=%" PRId32 " sent=%" PRId32 "\n",
wrb, TCP_WBSENT(wrb), conn->tx_unacked, conn->sent);
/* Free any write buffers that have exceed the retry count */
if (++TCP_WBNRTX(wrb) >= TCP_MAXRTX)
{
nwarn("WARNING: Expiring wrb=%p nrtx=%u\n",
wrb, TCP_WBNRTX(wrb));
/* Return the write buffer to the free list */
tcp_wrbuffer_release(wrb);
/* Notify any waiters if the write buffers have been
* drained.
*/
psock_writebuffer_notify(conn);
/* 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 TCP_ESTABLISHED
* state
*/
conn->expired++;
}
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 sequence number
* is pulled from the write_q again.
*/
ninfo("REXMIT: Moving wrb=%p nrtx=%u\n",
wrb, TCP_WBNRTX(wrb));
psock_insert_segment(wrb, &conn->write_q);
}
}
/****************************************************************************
* Name: psock_lost_connection
*
* Description:
* The TCP connection has been lost. Free all write buffers.
*
* Input Parameters:
* psock The socket structure
* conn The connection structure associated with the socket
*
* Returned Value:
* None
*
****************************************************************************/
static inline void psock_lost_connection(FAR struct tcp_conn_s *conn,
bool abort)
{
FAR sq_entry_t *entry;
FAR sq_entry_t *next;
/* Do not allow any further callbacks */
if (conn->sndcb != NULL)
{
conn->sndcb->flags = 0;
conn->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);
}
#if CONFIG_NET_SEND_BUFSIZE > 0
/* Notify the send buffer available */
tcp_sendbuffer_notify(conn);
#endif /* CONFIG_NET_SEND_BUFSIZE */
/* Reset write buffering variables */
sq_init(&conn->unacked_q);
sq_init(&conn->write_q);
/* Notify any waiters if the write buffers have been drained. */
psock_writebuffer_notify(conn);
conn->sent = 0;
conn->sndseq_max = 0;
/* Force abort the connection. */
if (abort)
{
conn->tx_unacked = 0;
conn->tcpstateflags = TCP_CLOSED;
}
}
/****************************************************************************
* Name: parse_sack
*
* Description:
* Parse sack from incoming TCP options
*
* Input Parameters:
* conn - The TCP connection of interest
* tcp - Header of tcp structure
* segs - Segments edge of sacks
*
* Returned Value:
* Number of sacks
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
#ifdef CONFIG_NET_TCP_SELECTIVE_ACK
static int parse_sack(FAR struct tcp_conn_s *conn, FAR struct tcp_hdr_s *tcp,
FAR struct tcp_ofoseg_s *segs)
{
FAR struct tcp_sack_s *sacks;
int nsack = 0;
uint8_t opt;
int i;
/* Get the size of the link layer header,
* the IP and TCP header
*/
for (i = 0; i < ((tcp->tcpoffset >> 4) - 5) << 2 ; )
{
opt = *(tcp->optdata + i);
if (opt == TCP_OPT_END)
{
/* End of options. */
break;
}
else if (opt == TCP_OPT_NOOP)
{
/* NOP option. */
++i;
continue;
}
else if (opt == TCP_OPT_SACK)
{
nsack = (*(tcp->optdata + 1 + i) -
TCP_OPT_SACK_PERM_LEN) /
(sizeof(uint32_t) * 2);
sacks = (FAR struct tcp_sack_s *)
(tcp->optdata + i +
TCP_OPT_SACK_PERM_LEN);
for (i = 0; i < nsack; i++)
{
/* Use the pointer to avoid the error of 4 byte alignment. */
segs[i].left = tcp_getsequence((uint8_t *)&sacks[i]);
segs[i].right = tcp_getsequence((uint8_t *)&sacks[i] + 4);
}
tcp_reorder_ofosegs(nsack, segs);
break;
}
else
{
/* All other options have a length field,
* so that we easily can skip past them.
*/
if (*(tcp->optdata + 1 + i) == 0)
{
/* If the length field is zero,
* the options are malformed and
* we don't process them further.
*/
break;
}
}
i += *(tcp->optdata + 1 + i);
}
return nsack;
}
#endif /* CONFIG_NET_TCP_SELECTIVE_ACK */
/****************************************************************************
* Name: psock_send_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 tcp_conn_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 psock_send_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvpriv, uint16_t flags)
{
FAR struct tcp_conn_s *conn = pvpriv;
#ifdef CONFIG_NET_TCP_SELECTIVE_ACK
struct tcp_ofoseg_s ofosegs[TCP_SACK_RANGES_MAX];
uint8_t nsacks = 0;
#endif
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
uint32_t rexmitno = 0;
#endif
/* Get the TCP connection pointer reliably from
* the corresponding TCP socket.
*/
DEBUGASSERT(conn != NULL);
/* The TCP socket is connected and, hence, should be bound to a device.
* Make sure that the polling device is the one that we are bound to.
*/
DEBUGASSERT(conn->dev != NULL);
if (dev != conn->dev)
{
return flags;
}
ninfo("flags: %04x\n", flags);
/* 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 acknowledgment, then update the count of
* acknowledged bytes.
*/
if ((flags & TCP_ACKDATA) != 0)
{
FAR struct tcp_wrbuffer_s *wrb;
FAR struct tcp_hdr_s *tcp;
FAR sq_entry_t *entry;
FAR sq_entry_t *next;
uint32_t ackno;
/* Get the offset address of the TCP header */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
if (conn->domain == PF_INET)
#endif
{
tcp = TCPIPv4BUF;
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else
#endif
{
tcp = TCPIPv6BUF;
}
#endif /* CONFIG_NET_IPv6 */
/* Get the ACK number from the TCP header */
ackno = tcp_getsequence(tcp->ackno);
ninfo("ACK: ackno=%" PRIu32 " 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 (TCP_SEQ_GT(ackno, TCP_WBSEQNO(wrb)))
{
/* Get the sequence number at the end of the data */
lastseq = TCP_WBSEQNO(wrb) + TCP_WBPKTLEN(wrb);
ninfo("ACK: wrb=%p seqno=%" PRIu32
" lastseq=%" PRIu32 " pktlen=%u ackno=%" PRIu32 "\n",
wrb, TCP_WBSEQNO(wrb), lastseq, TCP_WBPKTLEN(wrb),
ackno);
/* Has the entire buffer been ACKed? */
if (TCP_SEQ_GTE(ackno, lastseq))
{
ninfo("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);
/* Notify any waiters if the write buffers have been
* drained.
*/
psock_writebuffer_notify(conn);
}
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 = TCP_SEQ_SUB(ackno, TCP_WBSEQNO(wrb));
if (trimlen > TCP_WBSENT(wrb))
{
/* More data has been ACKed then we have sent? */
trimlen = TCP_WBSENT(wrb);
}
ninfo("ACK: wrb=%p trim %u bytes\n", wrb, trimlen);
TCP_WBTRIM(wrb, trimlen);
TCP_WBSEQNO(wrb) += trimlen;
TCP_WBSENT(wrb) -= trimlen;
/* Set the new sequence number for what remains */
ninfo("ACK: wrb=%p seqno=%" PRIu32 " pktlen=%u\n",
wrb, TCP_WBSEQNO(wrb), TCP_WBPKTLEN(wrb));
}
}
else if (ackno == TCP_WBSEQNO(wrb))
{
#ifdef CONFIG_NET_TCP_CC_NEWRENO
if (conn->dupacks >= TCP_FAST_RETRANSMISSION_THRESH)
#else
/* Reset the duplicate ack counter */
if ((flags & TCP_NEWDATA) != 0)
{
TCP_WBNACK(wrb) = 0;
}
/* Duplicate ACK? Retransmit data if need */
if (++TCP_WBNACK(wrb) == TCP_FAST_RETRANSMISSION_THRESH)
#endif
{
#ifdef CONFIG_NET_TCP_SELECTIVE_ACK
if ((conn->flags & TCP_SACK) &&
(tcp->tcpoffset & 0xf0) > 0x50)
{
/* Parse s-ack from tcp options */
nsacks = parse_sack(conn, tcp, ofosegs);
flags |= TCP_REXMIT;
}
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
else
#endif
#endif
{
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
/* Do fast retransmit */
rexmitno = ackno;
#ifndef CONFIG_NET_TCP_CC_NEWRENO
/* Reset counter */
TCP_WBNACK(wrb) = 0;
#endif
#endif
}
}
}
}
/* 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 && TCP_WBSENT(wrb) > 0 && TCP_SEQ_GT(ackno, TCP_WBSEQNO(wrb)))
{
uint32_t nacked;
/* Number of bytes that were ACKed */
nacked = TCP_SEQ_SUB(ackno, TCP_WBSEQNO(wrb));
if (nacked > TCP_WBSENT(wrb))
{
/* More data has been ACKed then we have sent? ASSERT? */
nacked = TCP_WBSENT(wrb);
}
ninfo("ACK: wrb=%p seqno=%" PRIu32
" nacked=%" PRIu32 " sent=%u ackno=%" PRIu32 "\n",
wrb, TCP_WBSEQNO(wrb), nacked, TCP_WBSENT(wrb), ackno);
/* Trim the ACKed bytes from the beginning of the write buffer. */
TCP_WBTRIM(wrb, nacked);
TCP_WBSEQNO(wrb) += nacked;
TCP_WBSENT(wrb) -= nacked;
ninfo("ACK: wrb=%p seqno=%" PRIu32 " pktlen=%u sent=%u\n",
wrb, TCP_WBSEQNO(wrb), TCP_WBPKTLEN(wrb), TCP_WBSENT(wrb));
}
}
/* Check for a loss of connection */
if ((flags & TCP_DISCONN_EVENTS) != 0)
{
ninfo("Lost connection: %04x\n", flags);
/* 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, conn->sndcb, flags);
}
/* Free write buffers and terminate polling */
psock_lost_connection(conn, !!(flags & NETDEV_DOWN));
return flags;
}
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
if (rexmitno != 0)
{
FAR struct tcp_wrbuffer_s *wrb;
FAR sq_entry_t *entry;
FAR sq_entry_t *next;
size_t sndlen;
int ret;
/* According to RFC 6298 (5.4), retransmit the earliest segment
* that has not been acknowledged by the TCP receiver.
*/
for (entry = sq_peek(&conn->unacked_q); entry; entry = next)
{
wrb = (FAR struct tcp_wrbuffer_s *)entry;
next = sq_next(entry);
if (rexmitno != TCP_WBSEQNO(wrb))
{
continue;
}
/* Reconstruct the length of the earliest segment to be
* retransmitted.
*/
sndlen = TCP_WBPKTLEN(wrb);
if (sndlen > conn->mss)
{
sndlen = conn->mss;
}
/* As we are retransmitting, the sequence number is expected
* already set for this write buffer.
*/
DEBUGASSERT(TCP_WBSEQNO(wrb) != (unsigned)-1);
#ifdef NEED_IPDOMAIN_SUPPORT
/* If both IPv4 and IPv6 support are enabled, then we will need to
* select which one to use when generating the outgoing packet.
* If only one domain is selected, then the setup is already in
* place and we need do nothing.
*/
tcp_ip_select(conn);
#endif
/* Then set-up to send that amount of data. (this won't actually
* happen until the polling cycle completes).
*/
tcp_setsequence(conn->sndseq, TCP_WBSEQNO(wrb));
ret = devif_iob_send(dev, TCP_WBIOB(wrb), sndlen,
0, tcpip_hdrsize(conn));
if (ret <= 0)
{
return flags;
}
#ifdef CONFIG_NET_TCP_CC_NEWRENO
/* After Fast retransmitted, set ssthresh to the maximum of
* the unacked and the 2*SMSS, and enter to Fast Recovery.
* ssthresh = max (FlightSize / 2, 2*SMSS) referring to rfc5681
* cwnd=ssthresh + 3*SMSS referring to rfc5681
*/
if (conn->flags & TCP_INFT)
{
tcp_cc_update(conn, NULL);
}
#endif
/* Reset the retransmission timer. */
tcp_update_retrantimer(conn, conn->rto);
/* Continue waiting */
return flags;
}
}
#endif
#ifdef CONFIG_NET_TCP_SELECTIVE_ACK
/* Check if we are being asked to retransmit s-ack data */
if (nsacks > 0)
{
FAR struct tcp_wrbuffer_s *wrb;
FAR sq_entry_t *entry;
FAR sq_entry_t *next;
uint32_t right;
int i;
/* Dump s-ack edge */
for (i = 0, right = 0; i < nsacks; i++)
{
ninfo("TCP SACK [%d]"
"[%" PRIu32 " : %" PRIu32 " : %" PRIu32 "]\n",
i, ofosegs[i].left, ofosegs[i].right,
TCP_SEQ_SUB(ofosegs[i].right, ofosegs[i].left));
}
for (entry = sq_peek(&conn->unacked_q); entry; entry = next)
{
wrb = (FAR struct tcp_wrbuffer_s *)entry;
next = sq_next(entry);
for (i = 0, right = 0; i < nsacks; i++)
{
/* Wrb seqno out of s-ack edge ? do retransmit ! */
if (TCP_SEQ_LT(TCP_WBSEQNO(wrb), ofosegs[i].left) &&
TCP_SEQ_GTE(TCP_WBSEQNO(wrb), right))
{
ninfo("TCP REXMIT "
"[%" PRIu32 " : %" PRIu32 " : %d]\n",
TCP_WBSEQNO(wrb),
TCP_SEQ_ADD(TCP_WBSEQNO(wrb), TCP_WBPKTLEN(wrb)),
TCP_WBPKTLEN(wrb));
sq_rem(entry, &conn->unacked_q);
retransmit_segment(conn, (FAR void *)entry);
break;
}
right = ofosegs[i].right;
}
}
#ifdef CONFIG_NET_TCP_CC_NEWRENO
/* After Fast retransmitted, set ssthresh to the maximum of
* the unacked and the 2*SMSS, and enter to Fast Recovery.
* ssthresh = max (FlightSize / 2, 2*SMSS) referring to rfc5681
* cwnd=ssthresh + 3*SMSS referring to rfc5681
*/
if (conn->flags & TCP_INFT)
{
tcp_cc_update(conn, NULL);
}
#endif
}
else
#endif
/* Check if we are being asked to retransmit data */
if ((flags & TCP_REXMIT) != 0)
{
FAR struct tcp_wrbuffer_s *wrb;
FAR sq_entry_t *entry;
ninfo("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);
ninfo("REXMIT: wrb=%p sent=%u\n", wrb, wrb ? TCP_WBSENT(wrb) : 0);
if (wrb != NULL && TCP_WBSENT(wrb) > 0)
{
FAR struct tcp_wrbuffer_s *tmp;
uint16_t sent;
/* Yes.. Reset the number of bytes sent sent from
* the write buffer
*/
sent = TCP_WBSENT(wrb);
if (conn->tx_unacked > sent)
{
conn->tx_unacked -= sent;
}
else
{
conn->tx_unacked = 0;
}
if (conn->sent > sent)
{
conn->sent -= sent;
}
else
{
conn->sent = 0;
}
TCP_WBSENT(wrb) = 0;
ninfo("REXMIT: wrb=%p sent=%u, "
"conn tx_unacked=%" PRId32 " sent=%" PRId32 "\n",
wrb, TCP_WBSENT(wrb), conn->tx_unacked, conn->sent);
/* Increment the retransmit count on this write buffer. */
if (++TCP_WBNRTX(wrb) >= TCP_MAXRTX)
{
nwarn("WARNING: Expiring wrb=%p nrtx=%u\n",
wrb, TCP_WBNRTX(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(tmp);
/* And return the write buffer to the free list */
tcp_wrbuffer_release(wrb);
/* Notify any waiters if the write buffers have been
* drained.
*/
psock_writebuffer_notify(conn);
/* 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 TCP_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)
{
retransmit_segment(conn, (FAR void *)entry);
}
}
#if CONFIG_NET_SEND_BUFSIZE > 0
/* Notify the send buffer available if wrbbuffer drained */
tcp_sendbuffer_notify(conn);
#endif /* CONFIG_NET_SEND_BUFSIZE */
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto event 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 or window size is zero. In that event, we
* will have to wait for the next polling cycle.
*/
if ((conn->tcpstateflags & TCP_ESTABLISHED) &&
((flags & TCP_NEWDATA) == 0) &&
(flags & (TCP_POLL | TCP_REXMIT | TCP_ACKDATA)) &&
!(sq_empty(&conn->write_q)) &&
conn->snd_wnd > 0)
{
FAR struct tcp_wrbuffer_s *wrb;
uint32_t predicted_seqno;
uint32_t seq;
uint32_t snd_wnd_edge;
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);
/* Set the sequence number for this segment. If we are
* retransmitting, then the sequence number will already
* be set for this write buffer.
*/
if (TCP_WBSEQNO(wrb) == (unsigned)-1)
{
TCP_WBSEQNO(wrb) = conn->isn + conn->sent;
}
/* 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.
*/
seq = TCP_WBSEQNO(wrb) + TCP_WBSENT(wrb);
#ifdef CONFIG_NET_TCP_CC_NEWRENO
snd_wnd_edge = conn->snd_wl2 + MIN(conn->snd_wnd, conn->cwnd);
#else
snd_wnd_edge = conn->snd_wl2 + conn->snd_wnd;
#endif
if (TCP_SEQ_LT(seq, snd_wnd_edge))
{
uint32_t remaining_snd_wnd;
int ret;
sndlen = TCP_WBPKTLEN(wrb) - TCP_WBSENT(wrb);
if (sndlen > conn->mss)
{
sndlen = conn->mss;
}
remaining_snd_wnd = TCP_SEQ_SUB(snd_wnd_edge, seq);
if (sndlen > remaining_snd_wnd)
{
sndlen = remaining_snd_wnd;
}
/* Normally CONFIG_IOB_THROTTLE should ensure that we have enough
* iob space available for copying the data to a packet buffer.
* If it doesn't, a deadlock could happen where the iobs are used
* by queued TX data and cannot be released because a full-sized
* packet gets refused by devif_iob_send(). Detect this situation
* and send tiny TCP packets until we manage to free up some space.
* We do not want to exhaust all of the remaining iobs by sending
* the maximum size packet that would fit.
*/
if (sndlen > iob_navail(false) * CONFIG_IOB_BUFSIZE)
{
nwarn("Running low on iobs, limiting packet size\n");
sndlen = CONFIG_IOB_BUFSIZE;
}
ninfo("SEND: wrb=%p seq=%" PRIu32 " pktlen=%u sent=%u sndlen=%zu "
"mss=%u snd_wnd=%u seq=%" PRIu32
" remaining_snd_wnd=%" PRIu32 "\n",
wrb, TCP_WBSEQNO(wrb), TCP_WBPKTLEN(wrb), TCP_WBSENT(wrb),
sndlen, conn->mss,
conn->snd_wnd, seq, remaining_snd_wnd);
/* 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.
*/
tcp_setsequence(conn->sndseq, TCP_WBSEQNO(wrb) + TCP_WBSENT(wrb));
#ifdef NEED_IPDOMAIN_SUPPORT
/* If both IPv4 and IPv6 support are enabled, then we will need to
* select which one to use when generating the outgoing packet.
* If only one domain is selected, then the setup is already in
* place and we need do nothing.
*/
tcp_ip_select(conn);
#endif
/* 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).
*/
ret = devif_iob_send(dev, TCP_WBIOB(wrb), sndlen,
TCP_WBSENT(wrb), tcpip_hdrsize(conn));
if (ret <= 0)
{
return flags;
}
/* 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->tx_unacked += sndlen;
conn->sent += sndlen;
/* Below prediction will become true,
* unless retransmission occurrence
*/
predicted_seqno = tcp_getsequence(conn->sndseq) + sndlen;
if (TCP_SEQ_GT(predicted_seqno, conn->sndseq_max))
{
conn->sndseq_max = predicted_seqno;
}
ninfo("SEND: wrb=%p nrtx=%u tx_unacked=%" PRIu32
" sent=%" PRIu32 "\n",
wrb, TCP_WBNRTX(wrb), conn->tx_unacked, conn->sent);
/* Increment the count of bytes sent from this write buffer */
TCP_WBSENT(wrb) += sndlen;
ninfo("SEND: wrb=%p sent=%u pktlen=%u\n",
wrb, TCP_WBSENT(wrb), TCP_WBPKTLEN(wrb));
/* Remove the write buffer from the write queue if the
* last of the data has been sent from the buffer.
*/
DEBUGASSERT(TCP_WBSENT(wrb) <= TCP_WBPKTLEN(wrb));
if (TCP_WBSENT(wrb) >= TCP_WBPKTLEN(wrb))
{
FAR struct tcp_wrbuffer_s *tmp;
ninfo("SEND: 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
*/
psock_insert_segment(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 &= ~TCP_POLL;
}
}
else
{
tcp_set_zero_probe(conn, flags);
}
/* Continue waiting */
return flags;
}
/****************************************************************************
* Name: tcp_max_wrb_size
*
* Description:
* Calculate the desired amount of data for a single
* struct tcp_wrbuffer_s.
*
****************************************************************************/
static uint32_t tcp_max_wrb_size(FAR struct tcp_conn_s *conn)
{
const uint32_t mss = conn->mss;
uint32_t size;
/* a few segments should be fine */
size = 4 * mss;
/* but it should not hog too many IOB buffers */
if (size > CONFIG_IOB_NBUFFERS * CONFIG_IOB_BUFSIZE / 2)
{
size = CONFIG_IOB_NBUFFERS * CONFIG_IOB_BUFSIZE / 2;
}
/* also, we prefer a multiple of mss */
if (size > mss)
{
const uint32_t odd = size % mss;
size -= odd;
}
DEBUGASSERT(size > 0);
ninfo("tcp_max_wrb_size = %" PRIu32 " for conn %p\n", size, conn);
return size;
}
/****************************************************************************
* Name: tcp_send_gettimeout
*
* Description:
* Calculate the send timeout
*
****************************************************************************/
static unsigned int tcp_send_gettimeout(clock_t start, unsigned int timeout)
{
unsigned int elapse;
if (timeout != UINT_MAX)
{
elapse = TICK2MSEC(clock_systime_ticks() - start);
if (elapse >= timeout)
{
timeout = 0;
}
else
{
timeout -= elapse;
}
}
return timeout;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: psock_tcp_send
*
* Description:
* psock_tcp_send() call may be used only when the TCP 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,
* -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.
* 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.
*
****************************************************************************/
ssize_t psock_tcp_send(FAR struct socket *psock, FAR const void *buf,
size_t len, int flags)
{
FAR struct tcp_conn_s *conn;
FAR struct tcp_wrbuffer_s *wrb;
FAR const uint8_t *cp;
unsigned int timeout;
ssize_t result = 0;
bool nonblock;
int ret = OK;
clock_t start;
if (psock == NULL || psock->s_type != SOCK_STREAM ||
psock->s_conn == NULL)
{
nerr("ERROR: Invalid socket\n");
ret = -EBADF;
goto errout;
}
conn = psock->s_conn;
if (!_SS_ISCONNECTED(conn->sconn.s_flags))
{
nerr("ERROR: Not connected\n");
ret = -ENOTCONN;
goto errout;
}
/* 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
if (psock->s_domain == PF_INET)
{
/* 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
if (psock->s_domain == PF_INET6)
{
/* Make sure that the IP address mapping is in the Neighbor Table */
ret = icmpv6_neighbor(NULL, conn->u.ipv6.raddr);
}
#endif /* CONFIG_NET_ICMPv6_NEIGHBOR */
/* Did we successfully get the address mapping? */
if (ret < 0)
{
nerr("ERROR: Not reachable\n");
ret = -ENETUNREACH;
goto errout;
}
#endif /* CONFIG_NET_ARP_SEND || CONFIG_NET_ICMPv6_NEIGHBOR */
nonblock = _SS_ISNONBLOCK(conn->sconn.s_flags) ||
(flags & MSG_DONTWAIT) != 0;
start = clock_systime_ticks();
timeout = _SO_TIMEOUT(conn->sconn.s_sndtimeo);
/* Dump the incoming buffer */
BUF_DUMP("psock_tcp_send", buf, len);
cp = buf;
while (len > 0)
{
uint32_t max_wrb_size;
unsigned int off;
size_t chunk_len = len;
ssize_t chunk_result;
net_lock();
/* Now that we have the network locked, we need to check the connection
* state again to ensure the connection is still valid.
*/
if (!_SS_ISCONNECTED(conn->sconn.s_flags))
{
nerr("ERROR: No longer connected\n");
ret = -ENOTCONN;
goto errout_with_lock;
}
/* Allocate resources to receive a callback */
if (conn->sndcb == NULL)
{
conn->sndcb = tcp_callback_alloc(conn);
/* Test if the callback has been allocated */
if (conn->sndcb == NULL)
{
/* A buffer allocation error occurred */
nerr("ERROR: Failed to allocate callback\n");
ret = nonblock ? -EAGAIN : -ENOMEM;
goto errout_with_lock;
}
}
/* Set up the callback in the connection */
conn->sndcb->flags = (TCP_ACKDATA | TCP_REXMIT | TCP_POLL |
TCP_DISCONN_EVENTS);
conn->sndcb->priv = (FAR void *)conn;
conn->sndcb->event = psock_send_eventhandler;
#if CONFIG_NET_SEND_BUFSIZE > 0
/* If the send buffer size exceeds the send limit,
* wait for the write buffer to be released
*/
while (tcp_wrbuffer_inqueue_size(conn) >= conn->snd_bufs)
{
if (nonblock)
{
ret = -EAGAIN;
goto errout_with_lock;
}
ret = net_sem_timedwait_uninterruptible(&conn->snd_sem,
tcp_send_gettimeout(start, timeout));
if (ret < 0)
{
if (ret == -ETIMEDOUT)
{
ret = -EAGAIN;
}
goto errout_with_lock;
}
}
#endif /* CONFIG_NET_SEND_BUFSIZE */
while (true)
{
struct iob_s *iob;
/* Allocate a write buffer. Careful, the network will be
* momentarily unlocked here.
*/
/* Try to coalesce into the last wrb.
*
* But only when it might yield larger segments.
* (REVISIT: It might make sense to lift this condition.
* IOB boundaries and segment boundaries usually do not match.
* It makes sense to save the number of IOBs.)
*
* Also, for simplicity, do it only when we haven't sent anything
* from the the wrb yet.
*/
max_wrb_size = tcp_max_wrb_size(conn);
wrb = (FAR struct tcp_wrbuffer_s *)sq_tail(&conn->write_q);
if (wrb != NULL && TCP_WBSENT(wrb) == 0 && TCP_WBNRTX(wrb) == 0 &&
TCP_WBPKTLEN(wrb) < max_wrb_size &&
(TCP_WBPKTLEN(wrb) % conn->mss) != 0)
{
wrb = (FAR struct tcp_wrbuffer_s *)sq_remlast(&conn->write_q);
ninfo("coalesce %zu bytes to wrb %p (%" PRIu16 ")\n", len, wrb,
TCP_WBPKTLEN(wrb));
DEBUGASSERT(TCP_WBPKTLEN(wrb) > 0);
}
else if (nonblock)
{
wrb = tcp_wrbuffer_tryalloc();
ninfo("new wrb %p (non blocking)\n", wrb);
}
else
{
wrb = tcp_wrbuffer_timedalloc(tcp_send_gettimeout(start,
timeout));
ninfo("new wrb %p\n", wrb);
}
if (wrb == NULL)
{
/* A buffer allocation error occurred */
nerr("ERROR: Failed to allocate write buffer\n");
if (nonblock || timeout != UINT_MAX)
{
ret = -EAGAIN;
}
else
{
ret = -ENOMEM;
}
goto errout_with_lock;
}
/* Initialize the write buffer */
TCP_WBSEQNO(wrb) = (unsigned)-1;
TCP_WBNRTX(wrb) = 0;
off = TCP_WBPKTLEN(wrb);
if (off + chunk_len > max_wrb_size)
{
chunk_len = max_wrb_size - off;
}
/* Copy the user data into the write buffer. We cannot wait for
* buffer space.
*/
/* The return value from TCP_WBTRYCOPYIN is either OK or
* -ENOMEM if less than the entire data chunk could be allocated.
* If -ENOMEM is returned, check if at least a part of the data
* chunk was allocated. If more than zero bytes were sent
* we return that number and let the caller deal with sending the
* remaining data.
*/
chunk_result = TCP_WBTRYCOPYIN(wrb, cp, chunk_len, off);
if (chunk_result == -ENOMEM)
{
if (TCP_WBPKTLEN(wrb) > 0)
{
DEBUGASSERT(TCP_WBPKTLEN(wrb) >= off);
chunk_result = TCP_WBPKTLEN(wrb) - off;
ninfo("INFO: Allocated part of the requested data "
"%zd/%zu\n",
chunk_result, chunk_len);
/* Note: chunk_result here can be 0 if we are trying
* to coalesce into the existing buffer and we failed
* to add anything.
*/
DEBUGASSERT(chunk_result >= 0);
}
else
{
chunk_result = 0;
}
}
else
{
DEBUGASSERT(chunk_result == chunk_len);
}
if (chunk_result > 0)
{
break;
}
/* release wrb */
if (TCP_WBPKTLEN(wrb) > 0)
{
DEBUGASSERT(TCP_WBSENT(wrb) == 0);
DEBUGASSERT(TCP_WBPKTLEN(wrb) > 0);
sq_addlast(&wrb->wb_node, &conn->write_q);
}
else
{
tcp_wrbuffer_release(wrb);
}
if (nonblock || (timeout != UINT_MAX &&
tcp_send_gettimeout(start, timeout) == 0))
{
nerr("ERROR: Failed to add data to the I/O chain\n");
ret = -EAGAIN;
goto errout_with_lock;
}
/* Wait for at least one IOB getting available.
*
* Note: net_ioballoc releases the network lock when blocking.
* It allows our write_q being drained in the meantime. Otherwise,
* we risk a deadlock with other threads competing on IOBs.
*/
iob = net_iobtimedalloc(true, tcp_send_gettimeout(start, timeout));
if (iob != NULL)
{
iob_free_chain(iob);
}
}
/* Dump I/O buffer chain */
TCP_WBDUMP("I/O buffer chain", wrb, TCP_WBPKTLEN(wrb), 0);
/* psock_send_eventhandler() will send data in FIFO order from the
* conn->write_q
*/
sq_addlast(&wrb->wb_node, &conn->write_q);
ninfo("Queued WRB=%p pktlen=%u write_q(%p,%p)\n",
wrb, TCP_WBPKTLEN(wrb),
conn->write_q.head, conn->write_q.tail);
/* Notify the device driver of the availability of TX data */
tcp_send_txnotify(psock, conn);
net_unlock();
if (chunk_result == 0)
{
DEBUGASSERT(nonblock);
if (result == 0)
{
result = -EAGAIN;
}
break;
}
if (chunk_result < 0)
{
if (result == 0)
{
result = chunk_result;
}
break;
}
DEBUGASSERT(chunk_result <= len);
DEBUGASSERT(chunk_result <= chunk_len);
DEBUGASSERT(result >= 0);
cp += chunk_result;
len -= chunk_result;
result += chunk_result;
}
/* Check for errors. Errors are signaled by negative errno values
* for the send length
*/
if (result < 0)
{
ret = result;
goto errout;
}
/* Return the number of bytes actually sent */
return result;
errout_with_lock:
net_unlock();
errout:
if (result > 0)
{
return result;
}
return ret;
}
/****************************************************************************
* Name: psock_tcp_cansend
*
* Description:
* psock_tcp_cansend() returns a value indicating if a write to the socket
* would block. No space in the buffer is actually reserved, so it is
* possible that the write may still block if the buffer is filled by
* another means.
*
* Input Parameters:
* conn The TCP connection of interest
*
* Returned Value:
* OK
* At least one byte of data could be successfully written.
* -EWOULDBLOCK
* There is no room in the output buffer.
* -EBADF
* An invalid descriptor was specified.
* -ENOTCONN
* The socket is not connected.
*
****************************************************************************/
int psock_tcp_cansend(FAR struct tcp_conn_s *conn)
{
/* Verify that we received a valid socket */
if (!conn)
{
nerr("ERROR: Invalid socket\n");
return -EBADF;
}
/* Verify that this is connected TCP socket */
if (!_SS_ISCONNECTED(conn->sconn.s_flags))
{
nwarn("WARNING: Not connected\n");
return -ENOTCONN;
}
/* In order to setup the send, we need to have at least one free write
* buffer head and at least one free IOB to initialize the write buffer
* head.
*
* REVISIT: The send will still block if we are unable to buffer
* the entire user-provided buffer which may be quite large.
* We will almost certainly need to have more than one free IOB,
* but we don't know how many more.
*/
if (tcp_wrbuffer_test() < 0 || iob_navail(true) <= 0
#if CONFIG_NET_SEND_BUFSIZE > 0
|| tcp_wrbuffer_inqueue_size(conn) >= conn->snd_bufs
#endif
)
{
return -EWOULDBLOCK;
}
return OK;
}
/****************************************************************************
* Name: tcp_sendbuffer_notify
*
* Description:
* Notify the send buffer semaphore
*
* Input Parameters:
* conn - The TCP connection of interest
*
* Assumptions:
* Called from user logic with the network locked.
*
****************************************************************************/
#if CONFIG_NET_SEND_BUFSIZE > 0
void tcp_sendbuffer_notify(FAR struct tcp_conn_s *conn)
{
int val = 0;
nxsem_get_value(&conn->snd_sem, &val);
if (val < 0)
{
nxsem_post(&conn->snd_sem);
}
}
#endif /* CONFIG_NET_SEND_BUFSIZE */
#endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCP_WRITE_BUFFERS */
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