/**************************************************************************** * net/tcp/tcp_send_unbuffered.c * * Copyright (C) 2007-2014 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 "netdev/netdev.h" #include "devif/devif.h" #include "tcp/tcp.h" #include "socket/socket.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #if defined(CONFIG_NET_TCP_SPLIT) && !defined(CONFIG_NET_TCP_SPLIT_SIZE) # define CONFIG_NET_TCP_SPLIT_SIZE 40 #endif #define TCPBUF ((struct tcp_iphdr_s *)&dev->d_buf[NET_LL_HDRLEN]) /**************************************************************************** * Private Types ****************************************************************************/ /* This structure holds the state of the send operation until it can be * operated upon from the interrupt level. */ 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 */ #if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK) uint32_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 ****************************************************************************/ /**************************************************************************** * Function: send_timeout * * Description: * Check for send timeout. * * Parameters: * pstate send state structure * * Returned Value: * TRUE:timeout FALSE:no timeout * * Assumptions: * Running at the interrupt level * ****************************************************************************/ #if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK) static inline int send_timeout(FAR struct send_s *pstate) { FAR struct socket *psock = 0; /* Check for a timeout configured via setsockopts(SO_SNDTIMEO). * If none... we well 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 && !CONFIG_DISABLE_CLOCK */ /**************************************************************************** * Function: tcpsend_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 tcpsend_interrupt(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; nllvdbg("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 & UIP_ACKDATA) != 0) { /* Update the timeout */ #if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK) pstate->snd_time = clock_systimer(); #endif /* The current acknowledgement number number is the (relative) offset * of the of the next byte needed by the receiver. The snd_isn is the * offset of the first byte to send to the receiver. The difference * is the number of bytes to be acknowledged. */ pstate->snd_acked = tcp_getsequence(TCPBUF->ackno) - pstate->snd_isn; nllvdbg("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 & UIP_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 & (UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT)) != 0) { /* Report not connected */ nllvdbg("Lost connection\n"); net_lostconnection(pstate->snd_sock, flags); pstate->snd_sent = -ENOTCONN; goto end_wait; } /* Check if the outgoing packet is available (it may have been claimed * by a sendto interrupt 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 & UIP_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. * tcp_mss(conn) will return 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 - tcp_mss(conn); /* 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 - tcp_mss(conn)) < 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 - tcp_mss(conn)) < 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 > tcp_mss(conn)) { sndlen = tcp_mss(conn); } /* 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: uIP 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; nllvdbg("SEND: sndseq %08x->%08x\n", conn->sndseq, seqno); tcp_setsequence(conn->sndseq, seqno); /* 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 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. Hence, we only check on the first packet -- when * snd_sent is zero. * * 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 (pstate->snd_sent != 0 || arp_find(conn->ripaddr) != NULL) #endif { /* Update the amount of data sent (but not necessarily ACKed) */ pstate->snd_sent += sndlen; nllvdbg("SEND: acked=%d sent=%d buflen=%d\n", pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen); } } } /* 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 defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK) if (send_timeout(pstate)) { /* Yes.. report the timeout */ nlldbg("SEND timeout\n"); pstate->snd_sent = -ETIMEDOUT; goto end_wait; } #endif /* CONFIG_NET_SOCKOPTS && !CONFIG_DISABLE_CLOCK */ /* 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 */ sem_post(&pstate->snd_sem); return flags; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Function: 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, * -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. * * Assumptions: * ****************************************************************************/ ssize_t psock_tcp_send(FAR struct socket *psock, FAR const void *buf, size_t len) { struct send_s state; net_lock_t save; int err; int ret = OK; /* Verify that the sockfd corresponds to valid, allocated socket */ if (!psock || psock->s_crefs <= 0) { err = EBADF; goto errout; } /* If this is an un-connected socket, then return ENOTCONN */ if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(psock->s_flags)) { err = ENOTCONN; goto errout; } /* 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 interrupts * disabled because we don't want anything to happen until we * are ready. */ save = net_lock(); memset(&state, 0, sizeof(struct send_s)); (void)sem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */ 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) { FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)psock->s_conn; /* 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 */ #if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK) state.snd_time = clock_systimer(); #endif /* Set up the callback in the connection */ state.snd_cb->flags = UIP_ACKDATA|UIP_REXMIT|UIP_POLL|UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT; state.snd_cb->priv = (void*)&state; state.snd_cb->event = tcpsend_interrupt; /* Notify the device driver of the availability of TX data */ netdev_txnotify(conn->ripaddr); /* Wait for the send to complete or an error to occur: NOTES: (1) * net_lockedwait will also terminate if a signal is received, (2) interrupts * may be disabled! They will be re-enabled while the task sleeps and * automatically re-enabled when the task restarts. */ ret = net_lockedwait(&state.snd_sem); /* Make sure that no further interrupts are processed */ tcp_callback_free(conn, state.snd_cb); } } sem_destroy(&state.snd_sem); net_unlock(save); /* 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) { err = state.snd_sent; goto errout; } /* If net_lockedwait failed, then we were probably reawakened by a signal. In * this case, net_lockedwait will have set errno appropriately. */ if (ret < 0) { err = -ret; goto errout; } /* Return the number of bytes actually sent */ return state.snd_sent; errout: set_errno(err); return ERROR; } #endif /* CONFIG_NET && CONFIG_NET_TCP && !CONFIG_NET_TCP_WRITE_BUFFERS */