diff options
Diffstat (limited to 'nuttx/net/uip/uip_tcpinput.c')
| -rw-r--r-- | nuttx/net/uip/uip_tcpinput.c | 839 |
1 files changed, 839 insertions, 0 deletions
diff --git a/nuttx/net/uip/uip_tcpinput.c b/nuttx/net/uip/uip_tcpinput.c new file mode 100644 index 000000000..5b40963b6 --- /dev/null +++ b/nuttx/net/uip/uip_tcpinput.c @@ -0,0 +1,839 @@ +/**************************************************************************** + * net/uip/uip_tcpinput.c + * Handling incoming TCP input + * + * Copyright (C) 2007-2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * Adapted for NuttX from logic in uIP which also has a BSD-like license: + * + * Original author Adam Dunkels <adam@dunkels.com> + * Copyright () 2001-2003, Adam Dunkels. + * All rights reserved. + * + * 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. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <nuttx/config.h> + +#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) + +#include <stdint.h> +#include <string.h> +#include <debug.h> + +#include <nuttx/net/uip/uipopt.h> +#include <nuttx/net/uip/uip.h> +#include <nuttx/net/uip/uip-arch.h> + +#include "uip_internal.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define BUF ((struct uip_tcpip_hdr *)&dev->d_buf[UIP_LLH_LEN]) + +/**************************************************************************** + * Public Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: uip_tcpinput + * + * Description: + * Handle incoming TCP input + * + * Parameters: + * dev - The device driver structure containing the received TCP packet. + * + * Return: + * None + * + * Assumptions: + * Called from the interrupt level or with interrupts disabled. + * + ****************************************************************************/ + +void uip_tcpinput(struct uip_driver_s *dev) +{ + struct uip_conn *conn = NULL; + struct uip_tcpip_hdr *pbuf = BUF; + uint16_t tmp16; + uint16_t flags; + uint8_t opt; + uint8_t result; + int len; + int i; + + dev->d_snddata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN]; + dev->d_appdata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN]; + +#ifdef CONFIG_NET_STATISTICS + uip_stat.tcp.recv++; +#endif + + /* Start of TCP input header processing code. */ + + if (uip_tcpchksum(dev) != 0xffff) + { + /* Compute and check the TCP checksum. */ + +#ifdef CONFIG_NET_STATISTICS + uip_stat.tcp.drop++; + uip_stat.tcp.chkerr++; +#endif + nlldbg("Bad TCP checksum\n"); + goto drop; + } + + /* Demultiplex this segment. First check any active connections. */ + + conn = uip_tcpactive(pbuf); + if (conn) + { + /* We found an active connection.. Check for the subsequent SYN + * arriving in UIP_SYN_RCVD state after the SYNACK packet was + * lost. To avoid other issues, reset any active connection + * where a SYN arrives in a state != UIP_SYN_RCVD. + */ + + if ((conn->tcpstateflags & UIP_TS_MASK) != UIP_SYN_RCVD && + (BUF->flags & TCP_CTL) == TCP_SYN) + { + goto reset; + } + else + { + goto found; + } + } + + /* If we didn't find and active connection that expected the packet, + * either (1) this packet is an old duplicate, or (2) this is a SYN packet + * destined for a connection in LISTEN. If the SYN flag isn't set, + * it is an old packet and we send a RST. + */ + + if ((pbuf->flags & TCP_CTL) == TCP_SYN) + { + /* This is a SYN packet for a connection. Find the connection + * listening on this port. + */ + + tmp16 = pbuf->destport; + if (uip_islistener(tmp16)) + { + /* We matched the incoming packet with a connection in LISTEN. + * We now need to create a new connection and send a SYNACK in + * response. + */ + + /* First allocate a new connection structure and see if there is any + * user application to accept it. + */ + + conn = uip_tcpaccept(pbuf); + if (conn) + { + /* The connection structure was successfully allocated. Now see if + * there is an application waiting to accept the connection (or at + * least queue it it for acceptance). + */ + + conn->crefs = 1; + if (uip_accept(dev, conn, tmp16) != OK) + { + /* No, then we have to give the connection back and drop the packet */ + + conn->crefs = 0; + uip_tcpfree(conn); + conn = NULL; + } + else + { + /* TCP state machine should move to the ESTABLISHED state only after + * it has received ACK from the host. This needs to be investigated + * further. + */ + + conn->tcpstateflags = UIP_ESTABLISHED; + } + } + + if (!conn) + { + /* Either (1) all available connections are in use, or (2) there is no + * application in place to accept the connection. We drop packet and hope that + * the remote end will retransmit the packet at a time when we + * have more spare connections or someone waiting to accept the connection. + */ + +#ifdef CONFIG_NET_STATISTICS + uip_stat.tcp.syndrop++; +#endif + nlldbg("No free TCP connections\n"); + goto drop; + } + + uip_incr32(conn->rcvseq, 1); + + /* Parse the TCP MSS option, if present. */ + + if ((pbuf->tcpoffset & 0xf0) > 0x50) + { + for (i = 0; i < ((pbuf->tcpoffset >> 4) - 5) << 2 ;) + { + opt = dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + i]; + if (opt == TCP_OPT_END) + { + /* End of options. */ + + break; + } + else if (opt == TCP_OPT_NOOP) + { + /* NOP option. */ + + ++i; + } + else if (opt == TCP_OPT_MSS && + dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == TCP_OPT_MSS_LEN) + { + /* An MSS option with the right option length. */ + + tmp16 = ((uint16_t)dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) | + (uint16_t)dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + i]; + conn->initialmss = conn->mss = + tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16; + + /* And we are done processing options. */ + + break; + } + else + { + /* All other options have a length field, so that we easily + * can skip past them. + */ + + if (dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == 0) + { + /* If the length field is zero, the options are malformed + * and we don't process them further. + */ + + break; + } + i += dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i]; + } + } + } + + /* Our response will be a SYNACK. */ + + uip_tcpack(dev, conn, TCP_ACK | TCP_SYN); + return; + } + } + + /* This is (1) an old duplicate packet or (2) a SYN packet but with + * no matching listener found. Send RST packet in either case. + */ + +reset: + + /* We do not send resets in response to resets. */ + + if ((pbuf->flags & TCP_RST) != 0) + { + goto drop; + } + +#ifdef CONFIG_NET_STATISTICS + uip_stat.tcp.synrst++; +#endif + uip_tcpreset(dev); + return; + +found: + + flags = 0; + + /* We do a very naive form of TCP reset processing; we just accept + * any RST and kill our connection. We should in fact check if the + * sequence number of this reset is within our advertised window + * before we accept the reset. + */ + + if ((pbuf->flags & TCP_RST) != 0) + { + conn->tcpstateflags = UIP_CLOSED; + nlldbg("RESET - TCP state: UIP_CLOSED\n"); + + (void)uip_tcpcallback(dev, conn, UIP_ABORT); + goto drop; + } + + /* Calculated the length of the data, if the application has sent + * any data to us. + */ + + len = (pbuf->tcpoffset >> 4) << 2; + + /* d_len will contain the length of the actual TCP data. This is + * calculated by subtracting the length of the TCP header (in + * len) and the length of the IP header (20 bytes). + */ + + dev->d_len -= (len + UIP_IPH_LEN); + + /* First, check if the sequence number of the incoming packet is + * what we're expecting next. If not, we send out an ACK with the + * correct numbers in, unless we are in the SYN_RCVD state and + * receive a SYN, in which case we should retransmit our SYNACK + * (which is done further down). + */ + + if (!((((conn->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) && + ((pbuf->flags & TCP_CTL) == (TCP_SYN | TCP_ACK))) || + (((conn->tcpstateflags & UIP_TS_MASK) == UIP_SYN_RCVD) && + ((pbuf->flags & TCP_CTL) == TCP_SYN)))) + { + if ((dev->d_len > 0 || ((pbuf->flags & (TCP_SYN | TCP_FIN)) != 0)) && + memcmp(pbuf->seqno, conn->rcvseq, 4) != 0) + { + uip_tcpsend(dev, conn, TCP_ACK, UIP_IPTCPH_LEN); + return; + } + } + + /* Next, check if the incoming segment acknowledges any outstanding + * data. If so, we update the sequence number, reset the length of + * the outstanding data, calculate RTT estimations, and reset the + * retransmission timer. + */ + + if ((pbuf->flags & TCP_ACK) != 0 && conn->unacked > 0) + { + uint32_t unackseq; + uint32_t ackseq; + + /* The next sequence number is equal to the current sequence + * number (sndseq) plus the size of the oustanding, unacknowledged + * data (unacked). + */ + + unackseq = uip_tcpaddsequence(conn->sndseq, conn->unacked); + + /* Get the sequence number of that has just been acknowledged by this + * incoming packet. + */ + + ackseq = uip_tcpgetsequence(pbuf->ackno); + + /* Check how many of the outstanding bytes have been acknowledged. For + * a most uIP send operation, this should always be true. However, + * the send() API sends data ahead when it can without waiting for + * the ACK. In this case, the 'ackseq' could be less than then the + * new sequence number. + */ + + if (ackseq <= unackseq) + { + /* Calculate the new number of oustanding, unacknowledged bytes */ + + conn->unacked = unackseq - ackseq; + } + else + { + /* What would it mean if ackseq > unackseq? The peer has ACKed + * more bytes than we think we have sent? Someone has lost it. + * Complain and reset the number of outstanding, unackowledged + * bytes + */ + + nlldbg("ERROR: ackseq[%08x] > unackseq[%08x]\n", ackseq, unackseq); + conn->unacked = 0; + } + + /* Update sequence number to the unacknowledge sequence number. If + * there is still outstanding, unacknowledged data, then this will + * be beyond ackseq. + */ + + nllvdbg("sndseq: %08x->%08x unackseq: %08x new unacked: %d\n", + conn->sndseq, ackseq, unackseq, conn->unacked); + uip_tcpsetsequence(conn->sndseq, ackseq); + + /* Do RTT estimation, unless we have done retransmissions. */ + + if (conn->nrtx == 0) + { + signed char m; + m = conn->rto - conn->timer; + + /* This is taken directly from VJs original code in his paper */ + + m = m - (conn->sa >> 3); + conn->sa += m; + if (m < 0) + { + m = -m; + } + + m = m - (conn->sv >> 2); + conn->sv += m; + conn->rto = (conn->sa >> 3) + conn->sv; + } + + /* Set the acknowledged flag. */ + + flags |= UIP_ACKDATA; + + /* Reset the retransmission timer. */ + + conn->timer = conn->rto; + } + + /* Do different things depending on in what state the connection is. */ + + switch (conn->tcpstateflags & UIP_TS_MASK) + { + /* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not + * implemented, since we force the application to close when the + * peer sends a FIN (hence the application goes directly from + * ESTABLISHED to LAST_ACK). + */ + + case UIP_SYN_RCVD: + /* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and + * we are waiting for an ACK that acknowledges the data we sent + * out the last time. Therefore, we want to have the UIP_ACKDATA + * flag set. If so, we enter the ESTABLISHED state. + */ + + if ((flags & UIP_ACKDATA) != 0) + { + conn->tcpstateflags = UIP_ESTABLISHED; + conn->unacked = 0; + nllvdbg("TCP state: UIP_ESTABLISHED\n"); + + flags = UIP_CONNECTED; + + if (dev->d_len > 0) + { + flags |= UIP_NEWDATA; + uip_incr32(conn->rcvseq, dev->d_len); + } + + dev->d_sndlen = 0; + result = uip_tcpcallback(dev, conn, flags); + uip_tcpappsend(dev, conn, result); + return; + } + + /* We need to retransmit the SYNACK */ + + if ((pbuf->flags & TCP_CTL) == TCP_SYN) + { + uip_tcpack(dev, conn, TCP_ACK | TCP_SYN); + return; + } + goto drop; + + case UIP_SYN_SENT: + /* In SYN_SENT, we wait for a SYNACK that is sent in response to + * our SYN. The rcvseq is set to sequence number in the SYNACK + * plus one, and we send an ACK. We move into the ESTABLISHED + * state. + */ + + if ((flags & UIP_ACKDATA) != 0 && (pbuf->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)) + { + /* Parse the TCP MSS option, if present. */ + + if ((pbuf->tcpoffset & 0xf0) > 0x50) + { + for (i = 0; i < ((pbuf->tcpoffset >> 4) - 5) << 2 ;) + { + opt = dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + i]; + if (opt == TCP_OPT_END) + { + /* End of options. */ + + break; + } + else if (opt == TCP_OPT_NOOP) + { + /* NOP option. */ + + ++i; + } + else if (opt == TCP_OPT_MSS && + dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == TCP_OPT_MSS_LEN) + { + /* An MSS option with the right option length. */ + + tmp16 = + (dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) | + dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + i]; + conn->initialmss = + conn->mss = + tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16; + + /* And we are done processing options. */ + + break; + } + else + { + /* All other options have a length field, so that we + * easily can skip past them. + */ + + if (dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == 0) + { + /* If the length field is zero, the options are + * malformed and we don't process them further. + */ + + break; + } + i += dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i]; + } + } + } + + conn->tcpstateflags = UIP_ESTABLISHED; + memcpy(conn->rcvseq, pbuf->seqno, 4); + nllvdbg("TCP state: UIP_ESTABLISHED\n"); + + uip_incr32(conn->rcvseq, 1); + conn->unacked = 0; + dev->d_len = 0; + dev->d_sndlen = 0; + result = uip_tcpcallback(dev, conn, UIP_CONNECTED | UIP_NEWDATA); + uip_tcpappsend(dev, conn, result); + return; + } + + /* Inform the application that the connection failed */ + + (void)uip_tcpcallback(dev, conn, UIP_ABORT); + + /* The connection is closed after we send the RST */ + + conn->tcpstateflags = UIP_CLOSED; + nllvdbg("Connection failed - TCP state: UIP_CLOSED\n"); + + /* We do not send resets in response to resets. */ + + if ((pbuf->flags & TCP_RST) != 0) + { + goto drop; + } + uip_tcpreset(dev); + return; + + case UIP_ESTABLISHED: + /* In the ESTABLISHED state, we call upon the application to feed + * data into the d_buf. If the UIP_ACKDATA flag is set, the + * application should put new data into the buffer, otherwise we are + * retransmitting an old segment, and the application should put that + * data into the buffer. + * + * If the incoming packet is a FIN, we should close the connection on + * this side as well, and we send out a FIN and enter the LAST_ACK + * state. We require that there is no outstanding data; otherwise the + * sequence numbers will be screwed up. + */ + + if ((pbuf->flags & TCP_FIN) != 0 && (conn->tcpstateflags & UIP_STOPPED) == 0) + { + if (conn->unacked > 0) + { + goto drop; + } + + /* Update the sequence number and indicate that the connection has + * been closed. + */ + + uip_incr32(conn->rcvseq, dev->d_len + 1); + flags |= UIP_CLOSE; + + if (dev->d_len > 0) + { + flags |= UIP_NEWDATA; + } + + (void)uip_tcpcallback(dev, conn, flags); + + conn->tcpstateflags = UIP_LAST_ACK; + conn->unacked = 1; + conn->nrtx = 0; + nllvdbg("TCP state: UIP_LAST_ACK\n"); + + uip_tcpsend(dev, conn, TCP_FIN | TCP_ACK, UIP_IPTCPH_LEN); + return; + } + + /* Check the URG flag. If this is set, the segment carries urgent + * data that we must pass to the application. + */ + + if ((pbuf->flags & TCP_URG) != 0) + { +#ifdef CONFIG_NET_TCPURGDATA + dev->d_urglen = (pbuf->urgp[0] << 8) | pbuf->urgp[1]; + if (dev->d_urglen > dev->d_len) + { + /* There is more urgent data in the next segment to come. */ + + dev->d_urglen = dev->d_len; + } + + uip_incr32(conn->rcvseq, dev->d_urglen); + dev->d_len -= dev->d_urglen; + dev->d_urgdata = dev->d_appdata; + dev->d_appdata += dev->d_urglen; + } + else + { + dev->d_urglen = 0; +#else /* CONFIG_NET_TCPURGDATA */ + dev->d_appdata = ((uint8_t*)dev->d_appdata) + ((pbuf->urgp[0] << 8) | pbuf->urgp[1]); + dev->d_len -= (pbuf->urgp[0] << 8) | pbuf->urgp[1]; +#endif /* CONFIG_NET_TCPURGDATA */ + } + + /* If d_len > 0 we have TCP data in the packet, and we flag this + * by setting the UIP_NEWDATA flag. If the application has stopped + * the dataflow using uip_stop(), we must not accept any data + * packets from the remote host. + */ + + if (dev->d_len > 0 && (conn->tcpstateflags & UIP_STOPPED) == 0) + { + flags |= UIP_NEWDATA; + } + + /* Check if the available buffer space advertised by the other end + * is smaller than the initial MSS for this connection. If so, we + * set the current MSS to the window size to ensure that the + * application does not send more data than the other end can + * handle. + * + * If the remote host advertises a zero window, we set the MSS to + * the initial MSS so that the application will send an entire MSS + * of data. This data will not be acknowledged by the receiver, + * and the application will retransmit it. This is called the + * "persistent timer" and uses the retransmission mechanim. + */ + + tmp16 = ((uint16_t)pbuf->wnd[0] << 8) + (uint16_t)pbuf->wnd[1]; + if (tmp16 > conn->initialmss || tmp16 == 0) + { + tmp16 = conn->initialmss; + } + conn->mss = tmp16; + + /* If this packet constitutes an ACK for outstanding data (flagged + * by the UIP_ACKDATA flag), we should call the application since it + * might want to send more data. If the incoming packet had data + * from the peer (as flagged by the UIP_NEWDATA flag), the + * application must also be notified. + * + * When the application is called, the d_len field + * contains the length of the incoming data. The application can + * access the incoming data through the global pointer + * d_appdata, which usually points UIP_IPTCPH_LEN + UIP_LLH_LEN + * bytes into the d_buf array. + * + * If the application wishes to send any data, this data should be + * put into the d_appdata and the length of the data should be + * put into d_len. If the application don't have any data to + * send, d_len must be set to 0. + */ + + if ((flags & (UIP_NEWDATA | UIP_ACKDATA)) != 0) + { + /* Clear sndlen and remember the size in d_len. The application + * may modify d_len and we will need this value later when we + * update the sequence number. + */ + + dev->d_sndlen = 0; + len = dev->d_len; + + /* Provide the packet to the application */ + + result = uip_tcpcallback(dev, conn, flags); + + /* If the application successfully handled the incoming data, + * then UIP_SNDACK will be set in the result. In this case, + * we need to update the sequence number. The ACK will be + * send by uip_tcpappsend(). + */ + + if ((result & UIP_SNDACK) != 0) + { + /* Update the sequence number using the saved length */ + + uip_incr32(conn->rcvseq, len); + } + + /* Send the response, ACKing the data or not, as appropriate */ + + uip_tcpappsend(dev, conn, result); + return; + } + goto drop; + + case UIP_LAST_ACK: + /* We can close this connection if the peer has acknowledged our + * FIN. This is indicated by the UIP_ACKDATA flag. + */ + + if ((flags & UIP_ACKDATA) != 0) + { + conn->tcpstateflags = UIP_CLOSED; + nllvdbg("UIP_LAST_ACK TCP state: UIP_CLOSED\n"); + + (void)uip_tcpcallback(dev, conn, UIP_CLOSE); + } + break; + + case UIP_FIN_WAIT_1: + /* The application has closed the connection, but the remote host + * hasn't closed its end yet. Thus we do nothing but wait for a + * FIN from the other side. + */ + + if (dev->d_len > 0) + { + uip_incr32(conn->rcvseq, dev->d_len); + } + + if ((pbuf->flags & TCP_FIN) != 0) + { + if ((flags & UIP_ACKDATA) != 0) + { + conn->tcpstateflags = UIP_TIME_WAIT; + conn->timer = 0; + conn->unacked = 0; + nllvdbg("TCP state: UIP_TIME_WAIT\n"); + } + else + { + conn->tcpstateflags = UIP_CLOSING; + nllvdbg("TCP state: UIP_CLOSING\n"); + } + + uip_incr32(conn->rcvseq, 1); + (void)uip_tcpcallback(dev, conn, UIP_CLOSE); + uip_tcpsend(dev, conn, TCP_ACK, UIP_IPTCPH_LEN); + return; + } + else if ((flags & UIP_ACKDATA) != 0) + { + conn->tcpstateflags = UIP_FIN_WAIT_2; + conn->unacked = 0; + nllvdbg("TCP state: UIP_FIN_WAIT_2\n"); + goto drop; + } + + if (dev->d_len > 0) + { + uip_tcpsend(dev, conn, TCP_ACK, UIP_IPTCPH_LEN); + return; + } + goto drop; + + case UIP_FIN_WAIT_2: + if (dev->d_len > 0) + { + uip_incr32(conn->rcvseq, dev->d_len); + } + + if ((pbuf->flags & TCP_FIN) != 0) + { + conn->tcpstateflags = UIP_TIME_WAIT; + conn->timer = 0; + nllvdbg("TCP state: UIP_TIME_WAIT\n"); + + uip_incr32(conn->rcvseq, 1); + (void)uip_tcpcallback(dev, conn, UIP_CLOSE); + uip_tcpsend(dev, conn, TCP_ACK, UIP_IPTCPH_LEN); + return; + } + + if (dev->d_len > 0) + { + uip_tcpsend(dev, conn, TCP_ACK, UIP_IPTCPH_LEN); + return; + } + goto drop; + + case UIP_TIME_WAIT: + uip_tcpsend(dev, conn, TCP_ACK, UIP_IPTCPH_LEN); + return; + + case UIP_CLOSING: + if ((flags & UIP_ACKDATA) != 0) + { + conn->tcpstateflags = UIP_TIME_WAIT; + conn->timer = 0; + nllvdbg("TCP state: UIP_TIME_WAIT\n"); + } + + default: + break; + } + +drop: + dev->d_len = 0; +} + +#endif /* CONFIG_NET && CONFIG_NET_TCP */ |