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nuttx/net/tcp/tcp_send.c

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/****************************************************************************
* net/tcp/tcp_send.c
*
* Copyright (C) 2007-2010, 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/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/netstats.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/tcp.h>
#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_ipaddr_hdrcopy(pbuf->srcipaddr, &dev->d_ipaddr);
net_ipaddr_hdrcopy(pbuf->destipaddr, &conn->ripaddr);
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 = IPTCP_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_ipaddr_hdrcopy(pbuf->destipaddr, pbuf->srcipaddr);
net_ipaddr_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;
/* 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(dev) / 256;
pbuf->optdata[3] = TCP_MSS(dev) & 255;
dev->d_len = IPTCP_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 */
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