/****************************************************************************
* uip_tcpconn.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Large parts of this file were leveraged from uIP logic:
*
* Copyright (c) 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.
*
****************************************************************************/
/****************************************************************************
* Compilation Switches
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_NET
#include <sys/types.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <net/uip/uipopt.h>
#include <net/uip/uip.h>
#include <net/uip/uip-arch.h>
#include "uip-internal.h"
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/* The array containing all uIP TCP connections. */
static struct uip_conn g_tcp_connections[UIP_CONNS];
/* A list of all free TCP connections */
static dq_queue_t g_free_tcp_connections;
/* A list of all connected TCP connections */
static dq_queue_t g_active_tcp_connections;
/* Last port used by a TCP connection connection. */
static uint16 g_last_tcp_port;
/* g_tcp_sequence[] is used to generate TCP sequence numbers */
static uint8 g_tcp_sequence[4];
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: uip_selectport()
*
* Description:
* If the portnumber is zero; select an unused port for the connection.
* If the portnumber is non-zero, verify that no other connection has
* been created with this port number.
*
* Input Parameters:
* portno -- the selected port number in host order. Zero means no port
* selected.
*
* Return:
* 0 on success, -ERRNO on failure
*
* Assumptions:
* Interrupts are disabled
*
****************************************************************************/
static int uip_selectport(uint16 portno)
{
if (portno == 0)
{
/* No local port assigned. Loop until we find a valid listen port number
* that is not being used by any other connection.
*/
do
{
/* Guess that the next available port number will be the one after
* the last port number assigned.
*/
portno = ++g_last_tcp_port;
/* Make sure that the port number is within range */
if (g_last_tcp_port >= 32000)
{
g_last_tcp_port = 4096;
}
}
while (uip_tcplistener(g_last_tcp_port));
}
else
{
/* A port number has been supplied. Verify that no other TCP/IP
* connection is using this local port.
*/
if (uip_tcplistener(portno))
{
/* It is in use... return EADDRINUSE */
return -EADDRINUSE;
}
}
/* Return the selecte or verified port number */
return portno;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: uip_tcpinit()
*
* Description:
* Initialize the TCP/IP connection structures. Called only once and only
* from the UIP layer at startup in normal user mode.
*
****************************************************************************/
void uip_tcpinit(void)
{
int i;
/* Initialize the queues */
dq_init(&g_free_tcp_connections);
dq_init(&g_active_tcp_connections);
/* Now initialize each connection structure */
for (i = 0; i < UIP_CONNS; i++)
{
/* Mark the connection closed and move it to the free list */
g_tcp_connections[i].tcpstateflags = UIP_CLOSED;
dq_addlast(&g_tcp_connections[i].node, &g_free_tcp_connections);
}
g_last_tcp_port = 1024;
}
/****************************************************************************
* Name: uip_tcpalloc()
*
* Description:
* Find a free TCP/IP connection structure and allocate it
* for use. This is normally something done by the implementation of the
* socket() API but is also called from the interrupt level when a TCP
* packet is received while "listening"
*
****************************************************************************/
struct uip_conn *uip_tcpalloc(void)
{
struct uip_conn *conn;
irqstate_t flags;
/* Because this routine is called from both interrupt level and
* and from user level, we have not option but to disable interrupts
* while accessing g_free_tcp_connections[];
*/
flags = irqsave();
/* Return the entry from the head of the free list */
conn = (struct uip_conn *)dq_remfirst(&g_free_tcp_connections);
#if 0 /* Revisit */
/* Is the free list empty? */
if (!conn)
{
/* As a fallback, check for connection structures in the TIME_WAIT
* state. If no CLOSED connections are found, then take the oldest
*/
struct uip_conn *tmp = g_active_tcp_connections.head;
while (tmp)
{
/* Is this connectin in the UIP_TIME_WAIT state? */
if (tmp->tcpstateflags == UIP_TIME_WAIT)
{
/* Is it the oldest one we have seen so far? */
if (!conn || tmp->timer > conn->timer)
{
/* Yes.. remember it */
conn = tmp;
}
}
/* Look at the next active connection */
tmp = tmp->node.flink;
}
/* If we found one, remove it from the active connection list */
dq_rem(&conn->node, &g_active_tcp_connections);
}
#endif
irqrestore(flags);
/* Mark the connection allocated */
if (conn)
{
conn->tcpstateflags = UIP_ALLOCATED;
}
return conn;
}
/****************************************************************************
* Name: uip_tcpfree()
*
* Description:
* Free a connection structure that is no longer in use. This should be
* done by the implementation of close()
*
****************************************************************************/
void uip_tcpfree(struct uip_conn *conn)
{
irqstate_t flags;
/* Because g_free_tcp_connections is accessed from user level and interrupt
* level, code, it is necessary to keep interrupts disabled during this
* operation.
*/
flags = irqsave();
/* UIP_ALLOCATED means that that the connection is not in the active list
* yet.
*/
if (conn->tcpstateflags != UIP_ALLOCATED)
{
/* Remove the connection from the active list */
dq_rem(&conn->node, &g_free_tcp_connections);
}
/* Mark the connection available and put it into the free list */
conn->tcpstateflags = UIP_CLOSED;
dq_addlast(&conn->node, &g_free_tcp_connections);
irqrestore(flags);
}
/****************************************************************************
* Name: uip_tcpactive()
*
* Description:
* Find a connection structure that is the appropriate
* connection to be used withi the provided TCP/IP header
*
* Assumptions:
* This function is called from UIP logic at interrupt level
*
****************************************************************************/
struct uip_conn *uip_tcpactive(struct uip_tcpip_hdr *buf)
{
struct uip_conn *conn = (struct uip_conn *)g_active_tcp_connections.head;
in_addr_t srcipaddr = uip_ip4addr_conv(buf->srcipaddr);
while (conn)
{
/* Find an open connection matching the tcp input */
if (conn->tcpstateflags != UIP_CLOSED &&
buf->destport == conn->lport && buf->srcport == conn->rport &&
uip_ipaddr_cmp(srcipaddr, conn->ripaddr))
{
/* Matching connection found.. break out of the loop and return a
* reference to it.
*/
break;
}
/* Look at the next active connection */
conn = (struct uip_conn *)conn->node.flink;
}
return conn;
}
/****************************************************************************
* Name: uip_nexttcpconn()
*
* Description:
* Traverse the list of active TCP connections
*
* Assumptions:
* This function is called from UIP logic at interrupt level (or with
* interrupts disabled).
*
****************************************************************************/
struct uip_conn *uip_nexttcpconn(struct uip_conn *conn)
{
if (!conn)
{
return (struct uip_conn *)g_active_tcp_connections.head;
}
else
{
return (struct uip_conn *)conn->node.flink;
}
}
/****************************************************************************
* Name: uip_tcplistener()
*
* Description:
* Given a local port number, find the TCP connection that listens on this
* this port.
*
* Primary uses: (1) to determine if a port number is available, (2) to
* To idenfity the socket that will accept new connections on a local port.
*
****************************************************************************/
struct uip_conn *uip_tcplistener(uint16 portno)
{
struct uip_conn *conn;
int i;
/* Check if this port number is in use by any active UIP TCP connection */
for (i = 0; i < UIP_CONNS; i++)
{
conn = &g_tcp_connections[i];
if (conn->tcpstateflags != UIP_CLOSED && conn->lport == htons(g_last_tcp_port))
{
/* The portnumber is in use, return the connection */
return conn;
}
}
return NULL;
}
/****************************************************************************
* Name: uip_tcpaccept()
*
* Description:
* Called when uip_interupt matches the incoming packet with a connection
* in LISTEN. In that case, this function will create a new connection and
* initialize it to send a SYNACK in return.
*
* Assumptions:
* This function is called from UIP logic at interrupt level
*
****************************************************************************/
struct uip_conn *uip_tcpaccept(struct uip_tcpip_hdr *buf)
{
struct uip_conn *conn = uip_tcpalloc();
if (conn)
{
/* Fill in the necessary fields for the new connection. */
conn->rto = conn->timer = UIP_RTO;
conn->sa = 0;
conn->sv = 4;
conn->nrtx = 0;
conn->lport = buf->destport;
conn->rport = buf->srcport;
uip_ipaddr_copy(conn->ripaddr, buf->srcipaddr);
conn->tcpstateflags = UIP_SYN_RCVD;
conn->snd_nxt[0] = g_tcp_sequence[0];
conn->snd_nxt[1] = g_tcp_sequence[1];
conn->snd_nxt[2] = g_tcp_sequence[2];
conn->snd_nxt[3] = g_tcp_sequence[3];
conn->len = 1;
/* rcv_nxt should be the seqno from the incoming packet + 1. */
conn->rcv_nxt[3] = buf->seqno[3];
conn->rcv_nxt[2] = buf->seqno[2];
conn->rcv_nxt[1] = buf->seqno[1];
conn->rcv_nxt[0] = buf->seqno[0];
}
return conn;
}
/****************************************************************************
* Name: uip_tcpnextsequence()
*
* Description:
* Increment the TCP/IP sequence number
*
* Assumptions:
* This function is called from the interrupt level
*
****************************************************************************/
void uip_tcpnextsequence(void)
{
/* This inplements a byte-by-byte big-endian increment */
if (++g_tcp_sequence[3] == 0)
{
if (++g_tcp_sequence[2] == 0)
{
if (++g_tcp_sequence[1] == 0)
{
++g_tcp_sequence[0];
}
}
}
}
/****************************************************************************
* Name: uip_tcpbind()
*
* Description:
* This function implements the UIP specific parts of the standard TCP
* bind() operation.
*
* Assumptions:
* This function is called from normal user level code.
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int uip_tcpbind(struct uip_conn *conn, const struct sockaddr_in6 *addr)
#else
int uip_tcpbind(struct uip_conn *conn, const struct sockaddr_in *addr)
#endif
{
irqstate_t flags;
int port;
/* Verify or select a local port */
flags = irqsave();
port = uip_selectport(ntohs(conn->lport));
irqrestore(flags);
if (port < 0)
{
return port;
}
#warning "Need to implement bind logic"
return -ENOSYS;
}
/****************************************************************************
* Name: uip_tcpconnect()
*
* Description:
* This function implements the UIP specific parts of the standard
* TCP connect() operation: It connects to a remote host using TCP.
*
* This function is used to start a new connection to the specified
* port on the specied host. It uses the connection structure that was
* allocated by a preceding socket() call. It sets the connection to
* the SYN_SENT state and sets the retransmission timer to 0. This will
* cause a TCP SYN segment to be sent out the next time this connection
* is periodically processed, which usually is done within 0.5 seconds
* after the call to uip_tcpconnect().
*
* Assumptions:
* This function is called from normal user level code.
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in6 *addr)
#else
int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in *addr)
#endif
{
irqstate_t flags;
int port;
/* The connection is expected to be in the UIP_ALLOCATED state.. i.e.,
* allocated via up_tcpalloc(), but not yet put into the active connections
* list.
*/
if (!conn || conn->tcpstateflags != UIP_ALLOCATED)
{
return -EISCONN;
}
/* If the TCP port has not alread been bound to a local port, then select
* one now.
*/
flags = irqsave();
port = uip_selectport(ntohs(conn->lport));
irqrestore(flags);
if (port < 0)
{
return port;
}
/* Initialize and return the connection structure, bind it to the port number */
conn->tcpstateflags = UIP_SYN_SENT;
conn->snd_nxt[0] = g_tcp_sequence[0];
conn->snd_nxt[1] = g_tcp_sequence[1];
conn->snd_nxt[2] = g_tcp_sequence[2];
conn->snd_nxt[3] = g_tcp_sequence[3];
conn->initialmss = conn->mss = UIP_TCP_MSS;
conn->len = 1; /* TCP length of the SYN is one. */
conn->nrtx = 0;
conn->timer = 1; /* Send the SYN next time around. */
conn->rto = UIP_RTO;
conn->sa = 0;
conn->sv = 16; /* Initial value of the RTT variance. */
conn->lport = htons((uint16)port);
/* The sockaddr port is 16 bits and already in network order */
conn->rport = addr->sin_port;
/* The sockaddr address is 32-bits in network order. */
uip_ipaddr_copy(conn->ripaddr, addr->sin_addr.s_addr);
/* And, finally, put the connection structure into the active
* list. Because g_active_tcp_connections is accessed from user level and
* interrupt level, code, it is necessary to keep interrupts disabled during
* this operation.
*/
flags = irqsave();
dq_addlast(&conn->node, &g_active_tcp_connections);
irqrestore(flags);
return OK;
}
#endif /* CONFIG_NET */
