/**************************************************************************** * net/tcp/tcp_send_unbuffered.c * * Copyright (C) 2007-2014, 2016-2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) && \ !defined(CONFIG_NET_TCP_WRITE_BUFFERS) #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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 clock_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. * * Input 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. * * Input 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. * * Input 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) >= 0) { /* 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. * * Input 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) * * Input 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). * * Input 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. * * Input Parameters: * psock An instance of the internal socket structure. * * Returned Value: * -ENOSYS (Function not implemented, always have to wait to send). * * Assumptions: * None * ****************************************************************************/ int psock_tcp_cansend(FAR struct socket *psock) { return -ENOSYS; } #endif /* CONFIG_NET && CONFIG_NET_TCP && !CONFIG_NET_TCP_WRITE_BUFFERS */