/**************************************************************************** * net/tcp/tcp_send_unbuffered.c * * SPDX-License-Identifier: Apache-2.0 * * 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 #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 "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 /**************************************************************************** * 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 tcp_conn_s *snd_conn; /* The TCP connection of interest */ 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_TCP_FAST_RETRANSMIT uint32_t snd_prev_ack; /* The previous ACKed seq number */ #ifdef CONFIG_NET_TCP_WINDOW_SCALE uint32_t snd_prev_wnd; /* The advertised window in the last * incoming acknowledgment */ #else uint16_t snd_prev_wnd; #endif int snd_dup_acks; /* Duplicate ACK counter */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * 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 * pvpriv An instance of struct send_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 tcpsend_eventhandler(FAR struct net_driver_s *dev, FAR void *pvpriv, uint16_t flags) { FAR struct send_s *pstate = pvpriv; FAR struct tcp_conn_s *conn; int ret; DEBUGASSERT(pstate != NULL); /* Get the TCP connection pointer reliably from * the corresponding TCP socket. */ conn = pstate->snd_conn; 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 acked: %" PRId32 " sent: %zd\n", flags, pstate->snd_acked, pstate->snd_sent); /* 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 acknowledgement, then update the count of * acknowledged bytes. * This condition is located here for performance reasons * (TCP_ACKDATA is the most frequent event). */ if ((flags & TCP_ACKDATA) != 0) { uint32_t ackno; FAR struct tcp_hdr_s *tcp; /* 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 */ /* 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. */ ackno = tcp_getsequence(tcp->ackno); pstate->snd_acked = TCP_SEQ_SUB(ackno, pstate->snd_isn); ninfo("ACK: acked=%" PRId32 " sent=%zd buflen=%zu\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; } #ifdef CONFIG_NET_TCP_FAST_RETRANSMIT /* Fast Retransmit (RFC 5681): an acknowledgment is considered a * "duplicate" when (a) the receiver of the ACK has outstanding data, * (b) the incoming acknowledgment carries no data, (c) the SYN and * FIN bits are both off, (d) the acknowledgment number is equal to * the greatest acknowledgment received on the given connection * and (e) the advertised window in the incoming acknowledgment equals * the advertised window in the last incoming acknowledgment. */ if (pstate->snd_acked < pstate->snd_sent && (flags & TCP_NEWDATA) == 0 && (tcp->flags & (TCP_SYN | TCP_FIN)) == 0 && ackno == pstate->snd_prev_ack && conn->snd_wnd == pstate->snd_prev_wnd) { if (++pstate->snd_dup_acks >= TCP_FAST_RETRANSMISSION_THRESH) { flags |= TCP_REXMIT; pstate->snd_dup_acks = 0; } } else { pstate->snd_dup_acks = 0; } pstate->snd_prev_ack = ackno; pstate->snd_prev_wnd = conn->snd_wnd; #endif } /* Check if we are being asked to retransmit data. * This condition is located here after TCP_ACKDATA for performance reasons * (TCP_REXMIT is less frequent than TCP_ACKDATA). */ if ((flags & TCP_REXMIT) != 0) { uint32_t sndlen; nwarn("WARNING: TCP_REXMIT\n"); /* According to RFC 6298 (5.4), retransmit the earliest segment * that has not been acknowledged by the TCP receiver. */ /* Reconstruct the length of the earliest segment to be retransmitted */ sndlen = pstate->snd_buflen - pstate->snd_acked; if (sndlen > conn->mss) { sndlen = conn->mss; } conn->rexmit_seq = pstate->snd_isn + pstate->snd_acked; #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). */ ret = devif_send(dev, &pstate->snd_buffer[pstate->snd_acked], sndlen, tcpip_hdrsize(conn)); if (ret <= 0) { pstate->snd_sent = ret; goto end_wait; } /* Continue waiting */ return flags; } /* Check for a loss of connection. * This condition is located here after both the TCP_ACKDATA and TCP_REXMIT * because TCP_DISCONN_EVENTS is the least frequent event. */ else if ((flags & TCP_DISCONN_EVENTS) != 0) { 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. */ if (_SS_ISCONNECTED(conn->sconn.s_flags)) { /* Report not connected */ tcp_lost_connection(conn, 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) { /* Get the amount of data that we can send in the next packet */ uint32_t sndlen = pstate->snd_buflen - pstate->snd_sent; if (sndlen > conn->mss) { sndlen = conn->mss; } /* Check if we have "space" in the window */ if ((pstate->snd_sent - pstate->snd_acked + sndlen) < conn->snd_wnd) { #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). */ ret = devif_send(dev, &pstate->snd_buffer[pstate->snd_sent], sndlen, tcpip_hdrsize(conn)); if (ret <= 0) { pstate->snd_sent = ret; goto end_wait; } /* Update the amount of data sent (but not necessarily ACKed) */ pstate->snd_sent += sndlen; ninfo("SEND: acked=%" PRId32 " sent=%zd buflen=%zu\n", pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen); } else { nwarn("WARNING: Window full, wait for ack\n"); } } /* Continue waiting */ return flags; end_wait: /* Do not allow any further callbacks */ DEBUGASSERT(pstate->snd_cb != NULL); pstate->snd_cb->flags = 0; pstate->snd_cb->priv = NULL; pstate->snd_cb->event = NULL; /* There are no outstanding, unacknowledged bytes */ conn->tx_unacked = 0; /* Wake up the waiting thread */ nxsem_post(&pstate->snd_sem); return flags; } /**************************************************************************** * 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, * 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, int flags) { 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_type != SOCK_STREAM || psock->s_conn == NULL) { nerr("ERROR: Invalid socket\n"); ret = -EBADF; goto errout; } conn = psock->s_conn; /* Check early if this is an un-connected socket, if so, then * return -ENOTCONN. Note, we will have to check this again, as we can't * guarantee the state won't change until we have the network locked. */ 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 */ /* 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(); /* 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"); net_unlock(); ret = -ENOTCONN; goto errout; } memset(&state, 0, sizeof(struct send_s)); nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */ state.snd_conn = conn; /* 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 */ ret = -ENOMEM; /* Assume allocation failure */ 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->tx_unacked = 0; /* 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 */ tcp_send_txnotify(psock, conn); /* Wait for the send to complete or an error to occur: NOTES: * net_sem_wait will also terminate if a signal is received. */ for (; ; ) { uint32_t acked = state.snd_acked; ret = net_sem_timedwait(&state.snd_sem, _SO_TIMEOUT(conn->sconn.s_sndtimeo)); if (ret != -ETIMEDOUT || acked == state.snd_acked) { if (ret == -ETIMEDOUT) { ret = -EAGAIN; } break; /* Timeout without any progress */ } } /* Make sure that no further events are processed */ tcp_callback_free(conn, state.snd_cb); } } nxsem_destroy(&state.snd_sem); net_unlock(); /* 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_sem_timedwait failed, then we were probably reawakened by a * signal. In this case, net_sem_timedwait 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: * conn The TCP connection of interest * * Returned Value: * OK (Always can send). * * Assumptions: * None * ****************************************************************************/ int psock_tcp_cansend(FAR struct tcp_conn_s *conn) { return OK; } #endif /* CONFIG_NET && CONFIG_NET_TCP && !CONFIG_NET_TCP_WRITE_BUFFERS */