/**************************************************************************** * net/tcp/tcp_recvfrom.c * * 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 #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" /**************************************************************************** * Private Types ****************************************************************************/ struct tcp_recvfrom_s { FAR struct tcp_conn_s *ir_conn; /* Connection associated with the socket */ 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) { unsigned int offset; 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 */ offset = (dev->d_appdata - dev->d_iob->io_data) - dev->d_iob->io_offset; recvlen = iob_copyout(pstate->ir_buffer, dev->d_iob, recvlen, offset); /* Trim the copied buffers */ dev->d_iob = iob_trimhead(dev->d_iob, recvlen + offset); 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 uint16_t tcp_newdata(FAR struct net_driver_s *dev, FAR struct tcp_recvfrom_s *pstate, uint16_t flags) { FAR struct tcp_conn_s *conn = pstate->ir_conn; /* 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) { uint16_t nsaved; uint16_t buflen = dev->d_len - recvlen; nsaved = tcp_datahandler(dev, conn, 0); if (nsaved < buflen) { nwarn("WARNING: packet data not fully saved " "(%d/%u/%zu/%u bytes)\n", buflen - nsaved, (unsigned int)nsaved, recvlen, (unsigned int)dev->d_len); } recvlen += nsaved; } else { netdev_iob_release(dev); } if (recvlen < dev->d_len) { /* Clear the TCP_CLOSE because we effectively dropped the FIN as well. */ flags &= ~TCP_CLOSE; } net_incr32(conn->rcvseq, recvlen); /* Indicate no data in the buffer */ dev->d_len = 0; return flags; } /**************************************************************************** * 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 = pstate->ir_conn; FAR struct iob_s *iob; int recvlen; /* Check there is any TCP data already buffered in a read-ahead * buffer. */ while ((iob = 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) { /* Free free the I/O buffer chain */ iob_free_chain(iob); conn->readahead = NULL; } else { /* The bytes that we have received from the head of the I/O * buffer chain. */ conn->readahead = iob_trimhead(iob, recvlen); } } } /**************************************************************************** * 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)); memset(infrom->sin_zero, 0, sizeof(infrom->sin_zero)); } } #endif /* CONFIG_NET_IPv4 */ } /**************************************************************************** * Name: tcp_recvhandler * * 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. * pvpriv An instance of struct tcp_recvfrom_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 tcp_recvhandler(FAR struct net_driver_s *dev, FAR void *pvpriv, uint16_t flags) { FAR struct tcp_recvfrom_s *pstate = pvpriv; 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) { /* Save the sender's address in the caller's 'from' location */ tcp_sender(dev, pstate); /* Copy the data from the packet (saving any unused bytes from the * packet in the read-ahead buffer). */ flags = tcp_newdata(dev, pstate, flags); /* 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 && (pstate->ir_cb->flags & TCP_WAITALL) == 0) || pstate->ir_buflen == 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 tcp_conn_s *conn = pstate->ir_conn; 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(conn != NULL); if (_SS_ISCONNECTED(conn->sconn.s_flags)) { /* Handle loss-of-connection event */ tcp_lost_connection(conn, 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: * conn The TCP connection of interest * 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 tcp_conn_s *conn, 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)); nxsem_init(&pstate->ir_sem, 0, 0); /* Doesn't really fail */ 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_conn = conn; } /* 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_sem_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 if any data were received. If so, then return their length and * ignore any error codes. */ if (pstate->ir_recvlen > 0) { return pstate->ir_recvlen; } /* If no data were received, return the error code instead. The event * handler error is prioritized over any previous error. */ return (pstate->ir_result < 0) ? pstate->ir_result : result; } /**************************************************************************** * 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 * msg Receive info and buffer for receive data * flags Receive flags * * 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 struct msghdr *msg, int flags) { FAR struct sockaddr *from = msg->msg_name; FAR socklen_t *fromlen = &msg->msg_namelen; FAR void *buf = msg->msg_iov->iov_base; size_t len = msg->msg_iov->iov_len; struct tcp_recvfrom_s state; FAR struct tcp_conn_s *conn; int ret; net_lock(); conn = (FAR struct tcp_conn_s *)psock->s_conn; /* Initialize the state structure. This is done with the network locked * because we don't want anything to happen until we are ready. */ tcp_recvfrom_initialize(conn, 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(conn->sconn.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(conn->sconn.s_flags)) { /* Nothing was previously received from the read-ahead 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(conn->sconn.s_flags) || (flags & MSG_DONTWAIT) != 0) { /* 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 that 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). * 3) If however MSG_WAITALL flag is set, block here till all requested * data are received (or there is a timeout / error). */ if (((flags & MSG_WAITALL) != 0 || state.ir_recvlen == 0) && state.ir_buflen > 0) { /* 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->flags |= (flags & MSG_WAITALL) ? TCP_WAITALL : 0; state.ir_cb->priv = (FAR void *)&state; state.ir_cb->event = tcp_recvhandler; /* Wait for either the receive to complete or for an error/timeout * to occur. net_sem_timedwait will also terminate if a signal is * received. */ ret = net_sem_timedwait(&state.ir_sem, _SO_TIMEOUT(conn->sconn.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 if (ret <= 0) { ret = -EBUSY; } } /* Receive additional data from read-ahead buffer, send the ACK timely. * * Revisit: Because IOBs are system-wide resources, consuming the read * ahead buffer would update recv window of all connections in the system, * not only this particular connection. */ if (tcp_should_send_recvwindow(conn)) { netdev_txnotify_dev(conn->dev); } net_unlock(); tcp_recvfrom_uninitialize(&state); return (ssize_t)ret; } #endif /* CONFIG_NET_TCP */