/**************************************************************************** * net/uip/uip_tcpcallback.c * * Copyright (C) 2007-2009 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) #include #include #include #include #include #include #include "uip_internal.h" /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Function: uip_readahead * * Description: * Copy as much received data as possible into the readahead buffer * * Assumptions: * This function is called at the interrupt level with interrupts disabled. * ****************************************************************************/ #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 static int uip_readahead(struct uip_readahead_s *readahead, uint8_t *buf, int len) { int available = CONFIG_NET_TCP_READAHEAD_BUFSIZE - readahead->rh_nbytes; int recvlen = 0; if (len > 0 && available > 0) { /* Get the length of the data to buffer. */ if (len > available) { recvlen = available; } else { recvlen = len; } /* Copy the new appdata into the read-ahead buffer */ memcpy(&readahead->rh_buffer[readahead->rh_nbytes], buf, recvlen); readahead->rh_nbytes += recvlen; } return recvlen; } #endif /**************************************************************************** * Function: uip_dataevent * * Description: * Handle data that is not accepted by the application because there is no * listener in place ready to receive the data. * * Assumptions: * - The caller has checked that UIP_NEWDATA is set in flags and that is no * other handler available to process the incoming data. * - This function is called at the interrupt level with interrupts disabled. * ****************************************************************************/ static inline uint16_t uip_dataevent(FAR struct uip_driver_s *dev, FAR struct uip_conn *conn, uint16_t flags) { uint16_t ret; /* Assume that we will ACK the data. The data will be ACKed if it is * placed in the read-ahead buffer -OR- if it zero length */ ret = (flags & ~UIP_NEWDATA) | UIP_SNDACK; /* Is there new data? With non-zero length? (Certain connection events * can have zero-length with UIP_NEWDATA set just to cause an ACK). */ if (dev->d_len > 0) { #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 uint8_t *buffer = dev->d_appdata; int buflen = dev->d_len; uint16_t recvlen; #endif nllvdbg("No listener on connection\n"); #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 /* Save as much data as possible in the read-ahead buffers */ recvlen = uip_datahandler(conn, buffer, buflen); /* There are several complicated buffering issues that are not addressed * properly here. For example, what if we cannot buffer the entire * packet? In that case, some data will be accepted but not ACKed. * Therefore it will be resent and duplicated. Fixing this could be tricky. */ if (recvlen < buflen) #endif { /* There is no handler to receive new data and there are no free * read-ahead buffers to retain the data -- drop the packet. */ nllvdbg("Dropped %d bytes\n", dev->d_len); #ifdef CONFIG_NET_STATISTICS uip_stat.tcp.syndrop++; uip_stat.tcp.drop++; #endif /* Clear the UIP_SNDACK bit so that no ACK will be sent */ ret &= ~UIP_SNDACK; } } /* In any event, the new data has now been handled */ dev->d_len = 0; return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Function: uip_tcpcallback * * Description: * Inform the application holding the TCP socket of a change in state. * * Assumptions: * This function is called at the interrupt level with interrupts disabled. * ****************************************************************************/ uint16_t uip_tcpcallback(struct uip_driver_s *dev, struct uip_conn *conn, uint16_t flags) { /* Preserve the UIP_ACKDATA, UIP_CLOSE, and UIP_ABORT in the response. * These is needed by uIP to handle responses and buffer state. The * UIP_NEWDATA indication will trigger the ACK response, but must be * explicitly set in the callback. */ nllvdbg("flags: %04x\n", flags); /* Perform the data callback. When a data callback is executed from 'list', * the input flags are normally returned, however, the implementation * may set one of the following: * * UIP_CLOSE - Gracefully close the current connection * UIP_ABORT - Abort (reset) the current connection on an error that * prevents UIP_CLOSE from working. * * And/Or set/clear the following: * * UIP_NEWDATA - May be cleared to indicate that the data was consumed * and that no further process of the new data should be * attempted. * UIP_SNDACK - If UIP_NEWDATA is cleared, then UIP_SNDACK may be set * to indicate that an ACK should be included in the response. * (In UIP_NEWDATA is cleared bu UIP_SNDACK is not set, then * dev->d_len should also be cleared). */ flags = uip_callbackexecute(dev, conn, flags, conn->list); /* There may be no new data handler in place at them moment that the new * incoming data is received. If the new incoming data was not handled, then * either (1) put the unhandled incoming data in the read-ahead buffer (if * enabled) or (2) suppress the ACK to the data in the hope that it will * be re-transmitted at a better time. */ if ((flags & UIP_NEWDATA) != 0) { /* Data was not handled.. dispose of it appropriately */ flags = uip_dataevent(dev, conn, flags); } /* Check if there is a connection-related event and a connection * callback. */ if (((flags & UIP_CONN_EVENTS) != 0) && conn->connection_event) { /* Perform the callback */ conn->connection_event(conn, flags); } return flags; } /**************************************************************************** * Function: uip_datahandler * * Description: * Handle data that is not accepted by the application. This may be called * either (1) from the data receive logic if it cannot buffer the data, or * (2) from the TCP event logic is there is no listener in place ready to * receive the data. * * Input Parmeters: * conn - A pointer to the TCP connection structure * buffer - A pointer to the buffer to be copied to the read-ahead * buffers * buflen - The number of bytes to copy to the read-ahead buffer. * * Returned value: * The number of bytes actually buffered. This could be less than 'nbytes' * if there is insufficient buffering available. * * Assumptions: * - The caller has checked that UIP_NEWDATA is set in flags and that is no * other handler available to process the incoming data. * - This function is called at the interrupt level with interrupts disabled. * ****************************************************************************/ #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 uint16_t uip_datahandler(FAR struct uip_conn *conn, FAR uint8_t *buffer, uint16_t buflen) { FAR struct uip_readahead_s *readahead1; FAR struct uip_readahead_s *readahead2 = NULL; uint16_t remaining; uint16_t recvlen = 0; /* First, we need to determine if we have space to buffer the data. This * needs to be verified before we actually begin buffering the data. We * will use any remaining space in the last allocated readahead buffer * plus as much one additional buffer. It is expected that the size of * readahead buffers are tuned so that one full packet will always fit * into one readahead buffer (for example if the buffer size is 420, then * a readahead buffer of 366 will hold a full packet of TCP data). */ readahead1 = (FAR struct uip_readahead_s*)conn->readahead.tail; if ((readahead1 && (CONFIG_NET_TCP_READAHEAD_BUFSIZE - readahead1->rh_nbytes) > buflen) || (readahead2 = uip_tcpreadaheadalloc()) != NULL) { /* We have buffer space. Now try to append add as much data as possible * to the last readahead buffer attached to this connection. */ remaining = buflen; if (readahead1) { recvlen = uip_readahead(readahead1, buffer, remaining); if (recvlen > 0) { buffer += recvlen; remaining -= recvlen; } } /* Do we need to buffer into the newly allocated buffer as well? */ if (readahead2) { readahead2->rh_nbytes = 0; recvlen += uip_readahead(readahead2, buffer, remaining); /* Save the readahead buffer in the connection structure where * it can be found with recv() is called. */ sq_addlast(&readahead2->rh_node, &conn->readahead); } } nllvdbg("Buffered %d bytes (of %d)\n", recvlen, buflen); return recvlen; } #endif /* CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 */ #endif /* CONFIG_NET && CONFIG_NET_TCP */