/**************************************************************************** * net/tcp/tcp_send.c * * Copyright (C) 2007-2010, 2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Adapted for NuttX from logic in uIP which also has a BSD-like license: * * Original author Adam Dunkels * 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 #if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) #include #include #include #include #include #include #include #include #include "devif/devif.h" #include "tcp/tcp.h" #include "utils/utils.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define BUF ((struct tcp_iphdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) /**************************************************************************** * Public Variables ****************************************************************************/ /**************************************************************************** * Private Variables ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_sendcomplete * * Description: * Complete the final portions of the send operation. This function sets * up IP header and computes the TCP checksum * * Parameters: * dev - The device driver structure to use in the send operation * * Return: * None * * Assumptions: * Called from the interrupt level or with interrupts disabled. * ****************************************************************************/ static void tcp_sendcomplete(FAR struct net_driver_s *dev) { FAR struct tcp_iphdr_s *pbuf = BUF; pbuf->ttl = IP_TTL; #ifdef CONFIG_NET_IPv6 /* For IPv6, the IP length field does not include the IPv6 IP header * length. */ pbuf->len[0] = ((dev->d_len - IPv6_HDRLEN) >> 8); pbuf->len[1] = ((dev->d_len - IPv6_HDRLEN) & 0xff); #else /* CONFIG_NET_IPv6 */ pbuf->len[0] = (dev->d_len >> 8); pbuf->len[1] = (dev->d_len & 0xff); #endif /* CONFIG_NET_IPv6 */ pbuf->urgp[0] = pbuf->urgp[1] = 0; /* Calculate TCP checksum. */ pbuf->tcpchksum = 0; pbuf->tcpchksum = ~(tcp_chksum(dev)); #ifdef CONFIG_NET_IPv6 pbuf->vtc = 0x60; pbuf->tcf = 0x00; pbuf->flow = 0x00; #else /* CONFIG_NET_IPv6 */ pbuf->vhl = 0x45; pbuf->tos = 0; pbuf->ipoffset[0] = 0; pbuf->ipoffset[1] = 0; ++g_ipid; pbuf->ipid[0] = g_ipid >> 8; pbuf->ipid[1] = g_ipid & 0xff; /* Calculate IP checksum. */ pbuf->ipchksum = 0; pbuf->ipchksum = ~(ipv4_chksum(dev)); #endif /* CONFIG_NET_IPv6 */ nllvdbg("Outgoing TCP packet length: %d (%d)\n", dev->d_len, (pbuf->len[0] << 8) | pbuf->len[1]); #ifdef CONFIG_NET_STATISTICS g_netstats.tcp.sent++; g_netstats.ip.sent++; #endif } /**************************************************************************** * Name: tcp_sendcommon * * Description: * We're done with the input processing. We are now ready to send a reply * Our job is to fill in all the fields of the TCP and IP headers before * calculating the checksum and finally send the packet. * * Parameters: * dev - The device driver structure to use in the send operation * conn - The TCP connection structure holding connection information * * Return: * None * * Assumptions: * Called from the interrupt level or with interrupts disabled. * ****************************************************************************/ static void tcp_sendcommon(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn) { FAR struct tcp_iphdr_s *pbuf = BUF; memcpy(pbuf->ackno, conn->rcvseq, 4); memcpy(pbuf->seqno, conn->sndseq, 4); pbuf->proto = IP_PROTO_TCP; pbuf->srcport = conn->lport; pbuf->destport = conn->rport; net_ipv4addr_hdrcopy(pbuf->srcipaddr, &dev->d_ipaddr); net_ipv4addr_hdrcopy(pbuf->destipaddr, &conn->u.ipv4.raddr); if (conn->tcpstateflags & TCP_STOPPED) { /* If the connection has issued TCP_STOPPED, we advertise a zero * window so that the remote host will stop sending data. */ pbuf->wnd[0] = 0; pbuf->wnd[1] = 0; } else { pbuf->wnd[0] = ((NET_DEV_RCVWNDO(dev)) >> 8); pbuf->wnd[1] = ((NET_DEV_RCVWNDO(dev)) & 0xff); } /* Finish the IP portion of the message, calculate checksums and send * the message. */ tcp_sendcomplete(dev); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_send * * Description: * Setup to send a TCP packet * * Parameters: * dev - The device driver structure to use in the send operation * conn - The TCP connection structure holding connection information * flags - flags to apply to the TCP header * len - length of the message * * Return: * None * * Assumptions: * Called from the interrupt level or with interrupts disabled. * ****************************************************************************/ void tcp_send(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn, uint16_t flags, uint16_t len) { FAR struct tcp_iphdr_s *pbuf = BUF; pbuf->flags = flags; dev->d_len = len; pbuf->tcpoffset = (TCP_HDRLEN / 4) << 4; tcp_sendcommon(dev, conn); } /**************************************************************************** * Name: tcp_reset * * Description: * Send a TCP reset (no-data) message * * Parameters: * dev - The device driver structure to use in the send operation * * Return: * None * * Assumptions: * Called from the interrupt level or with interrupts disabled. * ****************************************************************************/ void tcp_reset(FAR struct net_driver_s *dev) { FAR struct tcp_iphdr_s *pbuf = BUF; uint16_t tmp16; uint8_t seqbyte; #ifdef CONFIG_NET_STATISTICS g_netstats.tcp.rst++; #endif pbuf->flags = TCP_RST | TCP_ACK; dev->d_len = IPv4TCP_HDRLEN; pbuf->tcpoffset = 5 << 4; /* Flip the seqno and ackno fields in the TCP header. */ seqbyte = pbuf->seqno[3]; pbuf->seqno[3] = pbuf->ackno[3]; pbuf->ackno[3] = seqbyte; seqbyte = pbuf->seqno[2]; pbuf->seqno[2] = pbuf->ackno[2]; pbuf->ackno[2] = seqbyte; seqbyte = pbuf->seqno[1]; pbuf->seqno[1] = pbuf->ackno[1]; pbuf->ackno[1] = seqbyte; seqbyte = pbuf->seqno[0]; pbuf->seqno[0] = pbuf->ackno[0]; pbuf->ackno[0] = seqbyte; /* We also have to increase the sequence number we are * acknowledging. If the least significant byte overflowed, we need * to propagate the carry to the other bytes as well. */ if (++(pbuf->ackno[3]) == 0) { if (++(pbuf->ackno[2]) == 0) { if (++(pbuf->ackno[1]) == 0) { ++(pbuf->ackno[0]); } } } /* Swap port numbers. */ tmp16 = pbuf->srcport; pbuf->srcport = pbuf->destport; pbuf->destport = tmp16; /* Swap IP addresses. */ net_ipv4addr_hdrcopy(pbuf->destipaddr, pbuf->srcipaddr); net_ipv4addr_hdrcopy(pbuf->srcipaddr, &dev->d_ipaddr); /* And send out the RST packet */ tcp_sendcomplete(dev); } /**************************************************************************** * Name: tcp_ack * * Description: * Send the SYN or SYNACK response. * * Parameters: * dev - The device driver structure to use in the send operation * conn - The TCP connection structure holding connection information * ack - The ACK response to send * * Return: * None * * Assumptions: * Called from the interrupt level or with interrupts disabled. * ****************************************************************************/ void tcp_ack(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn, uint8_t ack) { struct tcp_iphdr_s *pbuf = BUF; uint16_t tcp_mss = TCP_IPv4_MSS(dev); /* Save the ACK bits */ pbuf->flags = ack; /* We send out the TCP Maximum Segment Size option with our ack. */ pbuf->optdata[0] = TCP_OPT_MSS; pbuf->optdata[1] = TCP_OPT_MSS_LEN; pbuf->optdata[2] = tcp_mss >> 8; pbuf->optdata[3] = tcp_mss & 0xff; dev->d_len = IPv4TCP_HDRLEN + TCP_OPT_MSS_LEN; pbuf->tcpoffset = ((TCP_HDRLEN + TCP_OPT_MSS_LEN) / 4) << 4; /* Complete the common portions of the TCP message */ tcp_sendcommon(dev, conn); } #endif /* CONFIG_NET && CONFIG_NET_TCP */