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nuttx/net/tcp/tcp_send_unbuffered.c
Gregory Nutt 9812f6f932 Trivial update to some comments
2018-02-22 18:42:27 -06:00

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/****************************************************************************
* net/tcp/tcp_send_unbuffered.c
*
* Copyright (C) 2007-2014, 2016-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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)
#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/clock.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/arp.h>
#include <nuttx/net/tcp.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 "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
#if defined(CONFIG_NET_TCP_SPLIT) && !defined(CONFIG_NET_TCP_SPLIT_SIZE)
# define CONFIG_NET_TCP_SPLIT_SIZE 40
#endif
#define TCPIPv4BUF ((struct tcp_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev) + IPv4_HDRLEN])
#define TCPIPv6BUF ((struct tcp_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev) + IPv6_HDRLEN])
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure holds the state of the send operation until it can be
* operated upon when the TX poll event occurs.
*/
struct send_s
{
FAR struct socket *snd_sock; /* Points to the parent socket structure */
FAR struct devif_callback_s *snd_cb; /* Reference to callback instance */
sem_t snd_sem; /* Used to wake up the waiting thread */
FAR const uint8_t *snd_buffer; /* Points to the buffer of data to send */
size_t snd_buflen; /* Number of bytes in the buffer to send */
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_SOCKOPTS
systime_t snd_time; /* Last send time for determining timeout */
#endif
#if defined(CONFIG_NET_TCP_SPLIT)
bool snd_odd; /* True: Odd packet in pair transaction */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: send_timeout
*
* Description:
* Check for send timeout.
*
* Parameters:
* pstate send state structure
*
* Returned Value:
* TRUE:timeout FALSE:no timeout
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
#ifdef CONFIG_NET_SOCKOPTS
static inline int send_timeout(FAR struct send_s *pstate)
{
FAR struct socket *psock;
/* Check for a timeout configured via setsockopts(SO_SNDTIMEO).
* If none... we will let the send wait forever.
*/
psock = pstate->snd_sock;
if (psock && psock->s_sndtimeo != 0)
{
/* Check if the configured timeout has elapsed */
return net_timeo(pstate->snd_time, psock->s_sndtimeo);
}
/* No timeout */
return FALSE;
}
#endif /* CONFIG_NET_SOCKOPTS */
/****************************************************************************
* Name: tcpsend_ipselect
*
* Description:
* 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.
*
* Parameters:
* dev - The structure of the network driver that caused the event
* pstate - sendto state structure
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
#ifdef NEED_IPDOMAIN_SUPPORT
static inline void tcpsend_ipselect(FAR struct net_driver_s *dev,
FAR struct tcp_conn_s *conn)
{
/* Which domain does the socket support */
if (conn->domain == PF_INET)
{
/* Select the IPv4 domain */
tcp_ipv4_select(dev);
}
else /* if (conn->domain == PF_INET6) */
{
/* Select the IPv6 domain */
DEBUGASSERT(conn->domain == PF_INET6);
tcp_ipv6_select(dev);
}
}
#endif
/****************************************************************************
* Name: psock_send_addrchck
*
* Description:
* Check if the destination IP address is in the IPv4 ARP or IPv6 Neighbor
* tables. If not, then the send won't actually make it out... it will be
* replaced with an ARP request (IPv4) or a Neighbor Solicitation (IPv6).
*
* NOTE 1: This could be an expensive check if there are a lot of
* entries in the ARP or Neighbor tables.
*
* 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 in many cases (IPv4 only).
*
* NOTE 3: If CONFIG_NET_ARP_SEND then we can be assured that the IP
* address mapping is already in the ARP table.
*
* Parameters:
* conn - The TCP connection structure
*
* Returned Value:
* true - The Ethernet MAC address is in the ARP or Neighbor table (OR
* the network device is not Ethernet).
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
#ifdef CONFIG_NET_ETHERNET
static inline bool psock_send_addrchck(FAR struct tcp_conn_s *conn)
{
/* Only Ethernet drivers are supported by this function */
/* REVISIT: Could the MAC address not also be in a routing table? */
if (conn->dev->d_lltype != NET_LL_ETHERNET)
{
/* Return true for non-Ethernet devices. */
return true;
}
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
if (conn->domain == PF_INET)
#endif
{
/* For historical reasons, we will return true if both the ARP and the
* routing table are disabled.
*/
bool ret = true;
#ifdef CONFIG_NET_ROUTE
in_addr_t router;
#endif
#if !defined(CONFIG_NET_ARP_IPIN) && !defined(CONFIG_NET_ARP_SEND)
if (arp_find(conn->u.ipv4.raddr) != NULL)
{
/* Return true if the address was found in the ARP table */
return true;
}
/* Otherwise, return false */
ret = false;
#endif
#ifdef CONFIG_NET_ROUTE
if (net_ipv4_router(conn->u.ipv4.raddr, &router) == OK)
{
/* Return true if the address was found in the routing table */
return true;
}
/* Otherwise, return false */
ret = false;
#endif
return ret;
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else
#endif
{
/* For historical reasons, we will return true if both the ICMPv6
* neighbor support and the routing table are disabled.
*/
bool ret = true;
#ifdef CONFIG_NET_ROUTE
net_ipv6addr_t router;
#endif
#if !defined(CONFIG_NET_ICMPv6_NEIGHBOR)
if (neighbor_findentry(conn->u.ipv6.raddr) != NULL)
{
/* Return true if the address was found in the ARP table */
return true;
}
/* Otherwise, return false */
ret = false;
#endif
#ifdef CONFIG_NET_ROUTE
if (net_ipv6_router(conn->u.ipv6.raddr, router) == OK)
{
/* Return true if the address was found in the routing table */
return true;
}
/* Otherwise, return false */
ret = false;
#endif
return ret;
}
#endif /* CONFIG_NET_IPv6 */
}
#else /* CONFIG_NET_ETHERNET */
# define psock_send_addrchck(r) (true)
#endif /* CONFIG_NET_ETHERNET */
/****************************************************************************
* Name: tcpsend_eventhandler
*
* Description:
* This function is called to perform the actual send operation when
* polled by the lower, device interfacing layer.
*
* Parameters:
* dev The structure of the network driver that caused the event
* conn The connection structure associated with the socket
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static uint16_t tcpsend_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvconn,
FAR void *pvpriv, uint16_t flags)
{
FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
FAR struct send_s *pstate = (FAR struct send_s *)pvpriv;
/* 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 acked: %d sent: %d\n",
flags, pstate->snd_acked, pstate->snd_sent);
/* If this packet contains an acknowledgement, then update the count of
* acknowledged bytes.
*/
if ((flags & TCP_ACKDATA) != 0)
{
FAR struct tcp_hdr_s *tcp;
/* Update the timeout */
#ifdef CONFIG_NET_SOCKOPTS
pstate->snd_time = clock_systimer();
#endif
/* Get the offset address of the TCP header */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
if (conn->domain == PF_INET)
#endif
{
DEBUGASSERT(IFF_IS_IPv4(dev->d_flags));
tcp = TCPIPv4BUF;
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else
#endif
{
DEBUGASSERT(IFF_IS_IPv6(dev->d_flags));
tcp = TCPIPv6BUF;
}
#endif /* CONFIG_NET_IPv6 */
/* The current acknowledgement number is the (relative) offset 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.
*/
pstate->snd_acked = tcp_getsequence(tcp->ackno) - pstate->snd_isn;
ninfo("ACK: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
/* Have all of the bytes in the buffer been sent and acknowledged? */
if (pstate->snd_acked >= pstate->snd_buflen)
{
/* Yes. Then pstate->snd_buflen should hold the number of bytes
* actually sent.
*/
goto end_wait;
}
/* No.. fall through to send more data if necessary */
}
/* Check if we are being asked to retransmit data */
else if ((flags & TCP_REXMIT) != 0)
{
/* Yes.. in this case, reset the number of bytes that have been sent
* to the number of bytes that have been ACKed.
*/
pstate->snd_sent = pstate->snd_acked;
#if defined(CONFIG_NET_TCP_SPLIT)
/* Reset the even/odd indicator to even since we need to
* retransmit.
*/
pstate->snd_odd = false;
#endif
/* Fall through to re-send data from the last that was ACKed */
}
/* Check for a loss of connection */
else if ((flags & TCP_DISCONN_EVENTS) != 0)
{
FAR struct socket *psock = pstate->snd_sock;
ninfo("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.
*/
DEBUGASSERT(psock != NULL);
if (_SS_ISCONNECTED(psock->s_flags))
{
/* Report not connected */
tcp_lost_connection(psock, pstate->snd_cb, flags);
}
pstate->snd_sent = -ENOTCONN;
goto end_wait;
}
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto event serving a different thread).
*/
#if 0 /* We can't really support multiple senders on the same TCP socket */
else if (dev->d_sndlen > 0)
{
/* Another thread has beat us sending data, wait for the next poll */
return flags;
}
#endif
/* 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 ((flags & TCP_NEWDATA) == 0 && pstate->snd_sent < pstate->snd_buflen)
{
uint32_t seqno;
/* Get the amount of data that we can send in the next packet */
uint32_t sndlen = pstate->snd_buflen - pstate->snd_sent;
#if defined(CONFIG_NET_TCP_SPLIT)
/* RFC 1122 states that a host may delay ACKing for up to 500ms but
* must respond to every second segment). This logic here will trick
* the RFC 1122 recipient into responding sooner. This logic will be
* activated if:
*
* 1. An even number of packets has been send (where zero is an even
* number),
* 2. There is more data be sent (more than or equal to
* CONFIG_NET_TCP_SPLIT_SIZE), but
* 3. Not enough data for two packets.
*
* Then we will split the remaining, single packet into two partial
* packets. This will stimulate the RFC 1122 peer to ACK sooner.
*
* Don't try to split very small packets (less than CONFIG_NET_TCP_SPLIT_SIZE).
* Only the first even packet and the last odd packets could have
* sndlen less than CONFIG_NET_TCP_SPLIT_SIZE. The value of sndlen on
* the last even packet is guaranteed to be at least MSS/2 by the
* logic below.
*/
if (sndlen >= CONFIG_NET_TCP_SPLIT_SIZE)
{
/* sndlen is the number of bytes remaining to be sent.
* conn->mss will provide the number of bytes that can sent
* in one packet. The difference, then, is the number of bytes
* that would be sent in the next packet after this one.
*/
int32_t next_sndlen = sndlen - conn->mss;
/* Is this the even packet in the packet pair transaction? */
if (!pstate->snd_odd)
{
/* next_sndlen <= 0 means that the entire remaining data
* could fit into this single packet. This is condition
* in which we must do the split.
*/
if (next_sndlen <= 0)
{
/* Split so that there will be an odd packet. Here
* we know that 0 < sndlen <= MSS
*/
sndlen = (sndlen / 2) + 1;
}
}
/* No... this is the odd packet in the packet pair transaction */
else
{
/* Will there be another (even) packet afer this one?
* (next_sndlen > 0) Will the split condition occur on that
* next, even packet? ((next_sndlen - conn->mss) < 0) If
* so, then perform the split now to avoid the case where the
* byte count is less than CONFIG_NET_TCP_SPLIT_SIZE on the
* next pair.
*/
if (next_sndlen > 0 && (next_sndlen - conn->mss) < 0)
{
/* Here, we know that sndlen must be MSS < sndlen <= 2*MSS
* and so (sndlen / 2) is <= MSS.
*/
sndlen /= 2;
}
}
}
/* Toggle the even/odd indicator */
pstate->snd_odd ^= true;
#endif /* CONFIG_NET_TCP_SPLIT */
if (sndlen > conn->mss)
{
sndlen = conn->mss;
}
/* Check if we have "space" in the window */
if ((pstate->snd_sent - pstate->snd_acked + sndlen) < conn->winsize)
{
/* Set the sequence number for this packet. NOTE: The network 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.
*/
seqno = pstate->snd_sent + pstate->snd_isn;
ninfo("SEND: sndseq %08x->%08x\n", conn->sndseq, seqno);
tcp_setsequence(conn->sndseq, seqno);
#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.
*/
tcpsend_ipselect(dev, conn);
#endif
/* Then set-up to send that amount of data. (this won't actually
* happen until the polling cycle completes).
*/
devif_send(dev, &pstate->snd_buffer[pstate->snd_sent], sndlen);
/* Check if the destination IP address is in the ARP or Neighbor
* table. If not, then the send won't actually make it out... it
* will be replaced with an ARP request or Neighbor Solicitation.
*/
if (pstate->snd_sent != 0 || psock_send_addrchck(conn))
{
/* Update the amount of data sent (but not necessarily ACKed) */
pstate->snd_sent += sndlen;
ninfo("SEND: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
}
}
}
#ifdef CONFIG_NET_SOCKOPTS
/* All data has been sent and we are just waiting for ACK or re-transmit
* indications to complete the send. Check for a timeout.
*/
if (send_timeout(pstate))
{
/* Yes.. report the timeout */
nwarn("WARNING: SEND timeout\n");
pstate->snd_sent = -ETIMEDOUT;
goto end_wait;
}
#endif /* CONFIG_NET_SOCKOPTS */
/* Continue waiting */
return flags;
end_wait:
/* Do not allow any further callbacks */
pstate->snd_cb->flags = 0;
pstate->snd_cb->priv = NULL;
pstate->snd_cb->event = NULL;
/* There are no outstanding, unacknowledged bytes */
conn->unacked = 0;
/* Wake up the waiting thread */
nxsem_post(&pstate->snd_sem);
return flags;
}
/****************************************************************************
* Name: send_txnotify
*
* Description:
* Notify the appropriate device driver that we are have data ready to
* be send (TCP)
*
* Parameters:
* psock - Socket state structure
* conn - The TCP connection structure
*
* Returned Value:
* None
*
****************************************************************************/
static inline void send_txnotify(FAR struct socket *psock,
FAR struct tcp_conn_s *conn)
{
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
/* If both IPv4 and IPv6 support are enabled, then we will need to select
* the device driver using the appropriate IP domain.
*/
if (psock->s_domain == PF_INET)
#endif
{
/* Notify the device driver that send data is available */
netdev_ipv4_txnotify(conn->u.ipv4.laddr, conn->u.ipv4.raddr);
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else /* if (psock->s_domain == PF_INET6) */
#endif /* CONFIG_NET_IPv4 */
{
/* Notify the device driver that send data is available */
DEBUGASSERT(psock->s_domain == PF_INET6);
netdev_ipv6_txnotify(conn->u.ipv6.laddr, conn->u.ipv6.raddr);
}
#endif /* CONFIG_NET_IPv6 */
}
/****************************************************************************
* 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).
*
* Parameters:
* psock An instance of the internal socket structure.
* buf Data to send
* len Length of data to send
*
* Returned Value:
* On success, returns the number of characters sent. On error,
* a negated errno value is returned.
*
* 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)
{
FAR struct tcp_conn_s *conn;
struct send_s state;
int ret = OK;
/* Verify that the sockfd corresponds to valid, allocated socket */
if (psock == NULL || psock->s_crefs <= 0)
{
nerr("ERROR: Invalid socket\n");
ret = -EBADF;
goto errout;
}
/* If this is an un-connected socket, then return ENOTCONN */
if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(psock->s_flags))
{
nerr("ERROR: Not connected\n");
ret = -ENOTCONN;
goto errout;
}
/* Make sure that we have the IP address mapping */
conn = (FAR struct tcp_conn_s *)psock->s_conn;
DEBUGASSERT(conn);
#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");
ret = -ENETUNREACH;
goto errout;
}
#endif /* CONFIG_NET_ARP_SEND || CONFIG_NET_ICMPv6_NEIGHBOR */
/* Set the socket state to sending */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
/* Perform the TCP send operation */
/* 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();
memset(&state, 0, sizeof(struct send_s));
/* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
(void)nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */
(void)nxsem_setprotocol(&state.snd_sem, SEM_PRIO_NONE);
state.snd_sock = psock; /* Socket descriptor to use */
state.snd_buflen = len; /* Number of bytes to send */
state.snd_buffer = buf; /* Buffer to send from */
if (len > 0)
{
/* Allocate resources to receive a callback */
state.snd_cb = tcp_callback_alloc(conn);
if (state.snd_cb)
{
/* 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->unacked = 0;
/* Set the initial time for calculating timeouts */
#ifdef CONFIG_NET_SOCKOPTS
state.snd_time = clock_systimer();
#endif
/* 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 = tcpsend_eventhandler;
/* Notify the device driver of the availability of TX data */
send_txnotify(psock, conn);
/* Wait for the send to complete or an error to occur: NOTES:
* net_lockedwait will also terminate if a signal is received.
*/
ret = net_lockedwait(&state.snd_sem);
/* Make sure that no further events are processed */
tcp_callback_free(conn, state.snd_cb);
}
}
nxsem_destroy(&state.snd_sem);
net_unlock();
/* Set the socket state to idle */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
/* Check for a errors. Errors are signalled by negative errno values
* for the send length
*/
if (state.snd_sent < 0)
{
ret = state.snd_sent;
goto errout;
}
/* If net_lockedwait failed, then we were probably reawakened by a signal. In
* this case, net_lockedwait will have returned negated errno appropriately.
*/
if (ret < 0)
{
goto errout;
}
/* Return the number of bytes actually sent */
ret = state.snd_sent;
errout:
return ret;
}
/****************************************************************************
* Name: psock_tcp_cansend
*
* Description:
* psock_tcp_cansend() returns a value indicating if a write to the socket
* would block. It is still possible that the write may block if another
* write occurs first.
*
* Parameters:
* psock An instance of the internal socket structure.
*
* Returned Value:
* OK (Function not implemented).
*
* Assumptions:
* None
*
****************************************************************************/
int psock_tcp_cansend(FAR struct socket *psock)
{
/* TODO: return OK unless someone is waiting for a packet to send */
return OK;
}
#endif /* CONFIG_NET && CONFIG_NET_TCP && !CONFIG_NET_TCP_WRITE_BUFFERS */
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