/**************************************************************************** * net/tcp/tcp_recvfrom.c * * Copyright (C) 2020 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 #ifdef CONFIG_NET_TCP #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 ****************************************************************************/ #define IPv4BUF ((struct ipv4_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) #define IPv6BUF ((struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) #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 ****************************************************************************/ struct tcp_recvfrom_s { FAR struct socket *ir_sock; /* The parent socket structure */ FAR struct devif_callback_s *ir_cb; /* Reference to callback instance */ sem_t ir_sem; /* Semaphore signals recv completion */ size_t ir_buflen; /* Length of receive buffer */ uint8_t *ir_buffer; /* Pointer to receive buffer */ FAR struct sockaddr *ir_from; /* Address of sender */ FAR socklen_t *ir_fromlen; /* Number of bytes allocated for address of sender */ ssize_t ir_recvlen; /* The received length */ int ir_result; /* Success:OK, failure:negated errno */ }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_update_recvlen * * Description: * Update information about space available for new data and update size * of data in buffer. * * Input Parameters: * pstate recvfrom state structure * recvlen size of new data appended to buffer * * Returned Value: * None * ****************************************************************************/ static inline void tcp_update_recvlen(FAR struct tcp_recvfrom_s *pstate, size_t recvlen) { if (pstate->ir_recvlen < 0) { pstate->ir_recvlen = 0; } pstate->ir_recvlen += recvlen; pstate->ir_buffer += recvlen; pstate->ir_buflen -= recvlen; } /**************************************************************************** * Name: tcp_recvfrom_newdata * * Description: * Copy the read data from the packet * * Input Parameters: * dev The structure of the network driver that generated the event. * pstate recvfrom state structure * * Returned Value: * The number of bytes taken from the packet. * * Assumptions: * The network is locked. * ****************************************************************************/ static size_t tcp_recvfrom_newdata(FAR struct net_driver_s *dev, FAR struct tcp_recvfrom_s *pstate) { size_t recvlen; /* Get the length of the data to return */ if (dev->d_len > pstate->ir_buflen) { recvlen = pstate->ir_buflen; } else { recvlen = dev->d_len; } /* Copy the new appdata into the user buffer */ memcpy(pstate->ir_buffer, dev->d_appdata, recvlen); ninfo("Received %d bytes (of %d)\n", (int)recvlen, (int)dev->d_len); /* Update the accumulated size of the data read */ tcp_update_recvlen(pstate, recvlen); return recvlen; } /**************************************************************************** * Name: tcp_newdata * * Description: * Copy the read data from the packet * * Input Parameters: * dev The structure of the network driver that generated the event * pstate recvfrom state structure * * Returned Value: * None. * * Assumptions: * The network is locked. * ****************************************************************************/ static inline void tcp_newdata(FAR struct net_driver_s *dev, FAR struct tcp_recvfrom_s *pstate) { /* Take as much data from the packet as we can */ size_t recvlen = tcp_recvfrom_newdata(dev, pstate); /* If there is more data left in the packet that we could not buffer, then * add it to the read-ahead buffers. */ if (recvlen < dev->d_len) { FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pstate->ir_sock->s_conn; FAR uint8_t *buffer = (FAR uint8_t *)dev->d_appdata + recvlen; uint16_t buflen = dev->d_len - recvlen; #ifdef CONFIG_DEBUG_NET uint16_t nsaved; nsaved = tcp_datahandler(conn, buffer, buflen); #else tcp_datahandler(conn, buffer, buflen); #endif /* There are complicated buffering issues that are not addressed fully * here. For example, what if up_datahandler() cannot buffer the * remainder of the packet? In that case, the data will be dropped but * still ACKed. Therefore it would not be resent. * * This is probably not an issue here because we only get here if the * read-ahead buffers are empty and there would have to be something * serioulsy wrong with the configuration not to be able to buffer a * partial packet in this context. */ #ifdef CONFIG_DEBUG_NET if (nsaved < buflen) { nerr("ERROR: packet data not saved (%d bytes)\n", buflen - nsaved); } #endif } /* Indicate no data in the buffer */ dev->d_len = 0; } /**************************************************************************** * Name: tcp_readahead * * Description: * Copy the read-ahead data from the packet * * Input Parameters: * pstate recvfrom state structure * * Returned Value: * None * * Assumptions: * The network is locked. * ****************************************************************************/ static inline void tcp_readahead(struct tcp_recvfrom_s *pstate) { FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pstate->ir_sock->s_conn; FAR struct iob_s *iob; int recvlen; /* Check there is any TCP data already buffered in a read-ahead * buffer. */ while ((iob = iob_peek_queue(&conn->readahead)) != NULL && pstate->ir_buflen > 0) { DEBUGASSERT(iob->io_pktlen > 0); /* Transfer that buffered data from the I/O buffer chain into * the user buffer. */ recvlen = iob_copyout(pstate->ir_buffer, iob, pstate->ir_buflen, 0); ninfo("Received %d bytes (of %d)\n", recvlen, iob->io_pktlen); /* Update the accumulated size of the data read */ tcp_update_recvlen(pstate, recvlen); /* If we took all of the data from the I/O buffer chain is empty, then * release it. If there is still data available in the I/O buffer * chain, then just trim the data that we have taken from the * beginning of the I/O buffer chain. */ if (recvlen >= iob->io_pktlen) { FAR struct iob_s *tmp; /* Remove the I/O buffer chain from the head of the read-ahead * buffer queue. */ tmp = iob_remove_queue(&conn->readahead); DEBUGASSERT(tmp == iob); UNUSED(tmp); /* And free the I/O buffer chain */ iob_free_chain(iob, IOBUSER_NET_TCP_READAHEAD); } else { /* The bytes that we have received from the head of the I/O * buffer chain (probably changing the head of the I/O * buffer queue). */ iob_trimhead_queue(&conn->readahead, recvlen, IOBUSER_NET_TCP_READAHEAD); } } } /**************************************************************************** * Name: tcp_sender * * Description: * Getting the sender's address from the UDP packet * * Input Parameters: * dev - The device driver data structure * pstate - the recvfrom state structure * * Returned Value: * None * * Assumptions: * The network is locked * ****************************************************************************/ static inline void tcp_sender(FAR struct net_driver_s *dev, FAR struct tcp_recvfrom_s *pstate) { /* Get the family from the packet type, IP address from the IP header, and * the port number from the TCP header. */ #ifdef CONFIG_NET_IPv6 #ifdef CONFIG_NET_IPv4 if (IFF_IS_IPv6(dev->d_flags)) #endif { FAR struct sockaddr_in6 *infrom = (FAR struct sockaddr_in6 *)pstate->ir_from; if (infrom) { FAR struct tcp_hdr_s *tcp = TCPIPv6BUF; FAR struct ipv6_hdr_s *ipv6 = IPv6BUF; infrom->sin6_family = AF_INET6; infrom->sin6_port = tcp->srcport; net_ipv6addr_copy(infrom->sin6_addr.s6_addr, ipv6->srcipaddr); } } #endif /* CONFIG_NET_IPv6 */ #ifdef CONFIG_NET_IPv4 #ifdef CONFIG_NET_IPv6 else #endif { FAR struct sockaddr_in *infrom = (FAR struct sockaddr_in *)pstate->ir_from; if (infrom) { FAR struct tcp_hdr_s *tcp = TCPIPv4BUF; FAR struct ipv4_hdr_s *ipv4 = IPv4BUF; infrom->sin_family = AF_INET; infrom->sin_port = tcp->srcport; net_ipv4addr_copy(infrom->sin_addr.s_addr, net_ip4addr_conv32(ipv4->srcipaddr)); } } #endif /* CONFIG_NET_IPv4 */ } /**************************************************************************** * Name: tcp_eventhandler * * Description: * This function is called with the network locked to perform the actual * TCP receive operation via by the lower, device interfacing layer. * * Input Parameters: * dev The structure of the network driver that generated the event. * pvconn 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 tcp_eventhandler(FAR struct net_driver_s *dev, FAR void *pvconn, FAR void *pvpriv, uint16_t flags) { FAR struct tcp_recvfrom_s *pstate = (struct tcp_recvfrom_s *)pvpriv; #if 0 /* REVISIT: The assertion fires. Why? */ FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn; /* The TCP socket is connected and, hence, should be bound to a device. * Make sure that the polling device is the own that we are bound to. */ DEBUGASSERT(conn->dev == NULL || conn->dev == dev); if (conn->dev != NULL && conn->dev != dev) { return flags; } #endif ninfo("flags: %04x\n", flags); /* 'priv' might be null in some race conditions (?) */ if (pstate) { /* If new data is available, then complete the read action. */ if ((flags & TCP_NEWDATA) != 0) { /* Copy the data from the packet (saving any unused bytes from the * packet in the read-ahead buffer). */ tcp_newdata(dev, pstate); /* Save the sender's address in the caller's 'from' location */ tcp_sender(dev, pstate); /* Indicate that the data has been consumed and that an ACK * should be sent. */ flags = (flags & ~TCP_NEWDATA) | TCP_SNDACK; /* Check for transfer complete. We will consider the * TCP/IP transfer complete as soon as any data has been received. * This is safe because if any additional data is received, it * will be retained in the TCP/IP read-ahead buffer until the * next receive is performed. */ if (pstate->ir_recvlen > 0) { ninfo("TCP resume\n"); /* The TCP receive buffer is non-empty. Return now and don't * allow any further TCP call backs. */ pstate->ir_cb->flags = 0; pstate->ir_cb->priv = NULL; pstate->ir_cb->event = NULL; /* Wake up the waiting thread, returning the number of bytes * actually read. */ nxsem_post(&pstate->ir_sem); } } /* Check for a loss of connection. * * TCP_DISCONN_EVENTS: * TCP_CLOSE: The remote host has closed the connection * TCP_ABORT: The remote host has aborted the connection * TCP_TIMEDOUT: Connection aborted due to too many retransmissions. * NETDEV_DOWN: The network device went down */ else if ((flags & TCP_DISCONN_EVENTS) != 0) { FAR struct socket *psock = pstate->ir_sock; nwarn("WARNING: 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)) { /* Handle loss-of-connection event */ tcp_lost_connection(psock, pstate->ir_cb, flags); } /* Check if the peer gracefully closed the connection. */ if ((flags & TCP_CLOSE) != 0) { /* This case should always return success (zero)! The value of * ir_recvlen, if zero, will indicate that the connection was * gracefully closed. */ pstate->ir_result = 0; } else { pstate->ir_result = -ENOTCONN; } /* Wake up the waiting thread */ nxsem_post(&pstate->ir_sem); } } return flags; } /**************************************************************************** * Name: tcp_recvfrom_initialize * * Description: * Initialize the state structure * * Input Parameters: * psock Pointer to the socket structure for the socket * buf Buffer to receive data * len Length of buffer * pstate A pointer to the state structure to be initialized * * Returned Value: * None * * Assumptions: * ****************************************************************************/ static void tcp_recvfrom_initialize(FAR struct socket *psock, FAR void *buf, size_t len, FAR struct sockaddr *infrom, FAR socklen_t *fromlen, FAR struct tcp_recvfrom_s *pstate) { /* Initialize the state structure. */ memset(pstate, 0, sizeof(struct tcp_recvfrom_s)); /* This semaphore is used for signaling and, hence, should not have * priority inheritance enabled. */ nxsem_init(&pstate->ir_sem, 0, 0); /* Doesn't really fail */ nxsem_setprotocol(&pstate->ir_sem, SEM_PRIO_NONE); pstate->ir_buflen = len; pstate->ir_buffer = buf; pstate->ir_from = infrom; pstate->ir_fromlen = fromlen; /* Set up the start time for the timeout */ pstate->ir_sock = psock; } /* The only un-initialization that has to be performed is destroying the * semaphore. */ #define tcp_recvfrom_uninitialize(s) nxsem_destroy(&(s)->ir_sem) /**************************************************************************** * Name: tcp_recvfrom_result * * Description: * Evaluate the result of the recv operations * * Input Parameters: * result The result of the net_timedwait operation (may indicate EINTR) * pstate A pointer to the state structure to be initialized * * Returned Value: * The result of the recv operation with errno set appropriately * * Assumptions: * ****************************************************************************/ static ssize_t tcp_recvfrom_result(int result, struct tcp_recvfrom_s *pstate) { /* Check for a error/timeout detected by the event handler. Errors are * signaled by negative errno values for the rcv length */ if (pstate->ir_result < 0) { /* This might return EAGAIN on a timeout or ENOTCONN on loss of * connection (TCP only) */ return pstate->ir_result; } /* If net_timedwait failed, then we were probably reawakened by a signal. In * this case, net_timedwait will have returned negated errno appropriately. */ if (result < 0) { return result; } return pstate->ir_recvlen; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: psock_tcp_recvfrom * * Description: * Perform the recvfrom operation for a TCP/IP SOCK_STREAM * * Input Parameters: * psock Pointer to the socket structure for the SOCK_DRAM socket * buf Buffer to receive data * len Length of buffer * from INET address of source (may be NULL) * * Returned Value: * On success, returns the number of characters received. On error, * -errno is returned (see recvfrom for list of errnos). * * Assumptions: * ****************************************************************************/ ssize_t psock_tcp_recvfrom(FAR struct socket *psock, FAR void *buf, size_t len, FAR struct sockaddr *from, FAR socklen_t *fromlen) { struct tcp_recvfrom_s state; int ret; /* 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(); tcp_recvfrom_initialize(psock, buf, len, from, fromlen, &state); /* Handle any any TCP data already buffered in a read-ahead buffer. NOTE * that there may be read-ahead data to be retrieved even after the * socket has been disconnected. */ tcp_readahead(&state); /* The default return value is the number of bytes that we just copied * into the user buffer. We will return this if the socket has become * disconnected or if the user request was completely satisfied with * data from the readahead buffers. */ ret = state.ir_recvlen; /* Verify that the SOCK_STREAM has been and still is connected */ if (!_SS_ISCONNECTED(psock->s_flags)) { /* Was any data transferred from the readahead buffer after we were * disconnected? If so, then return the number of bytes received. We * will wait to return end disconnection indications the next time that * recvfrom() is called. * * If no data was received (i.e., ret == 0 -- it will not be negative) * and the connection was gracefully closed by the remote peer, then return * success. If ir_recvlen is zero, the caller of recvfrom() will get an * end-of-file indication. */ if (ret <= 0 && !_SS_ISCLOSED(psock->s_flags)) { /* Nothing was previously received from the readahead buffers. * The SOCK_STREAM must be (re-)connected in order to receive any * additional data. */ ret = -ENOTCONN; } } /* In general, this implementation will not support non-blocking socket * operations... except in a few cases: Here for TCP receive with read-ahead * enabled. If this socket is configured as non-blocking then return EAGAIN * if no data was obtained from the read-ahead buffers. */ else if (_SS_ISNONBLOCK(psock->s_flags)) { /* Return the number of bytes read from the read-ahead buffer if * something was received (already in 'ret'); EAGAIN if not. */ if (ret <= 0) { /* Nothing was received */ ret = -EAGAIN; } } /* It is okay to block if we need to. If there is space to receive anything * more, then we will wait to receive the data. Otherwise return the number * of bytes read from the read-ahead buffer (already in 'ret'). */ else /* We get here when we we decide that we need to setup the wait for incoming * TCP/IP data. Just a few more conditions to check: * * 1) Make sure thet there is buffer space to receive additional data * (state.ir_buflen > 0). This could be zero, for example, we filled * the user buffer with data from the read-ahead buffers. And * 2) then we not want to wait if we already obtained some data from the * read-ahead buffer. In that case, return now with what we have (don't * want for more because there may be no timeout). */ if (state.ir_recvlen == 0 && state.ir_buflen > 0) { FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)psock->s_conn; /* Set up the callback in the connection */ state.ir_cb = tcp_callback_alloc(conn); if (state.ir_cb) { state.ir_cb->flags = (TCP_NEWDATA | TCP_DISCONN_EVENTS); state.ir_cb->priv = (FAR void *)&state; state.ir_cb->event = tcp_eventhandler; /* Wait for either the receive to complete or for an error/timeout * to occur. net_timedwait will also terminate if a signal isi * received. */ ret = net_timedwait(&state.ir_sem, _SO_TIMEOUT(psock->s_rcvtimeo)); if (ret == -ETIMEDOUT) { ret = -EAGAIN; } /* Make sure that no further events are processed */ tcp_callback_free(conn, state.ir_cb); ret = tcp_recvfrom_result(ret, &state); } else { ret = -EBUSY; } } net_unlock(); tcp_recvfrom_uninitialize(&state); return (ssize_t)ret; } #endif /* CONFIG_NET_TCP */