/****************************************************************************
* net/tcp/tcp_conn.c
*
* Copyright (C) 2007-2011, 2013-2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP)
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/uip.h>
#include <nuttx/net/netdev.h>
#include "tcp/tcp.h"
#include "uip/uip.h"
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/* The array containing all uIP TCP connections. */
static struct tcp_conn_s g_tcp_connections[CONFIG_NET_TCP_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_t g_last_tcp_port;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: uip_selectport()
*
* Description:
* If the port number is zero; select an unused port for the connection.
* If the port number 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, negated errno on failure:
*
* EADDRINUSE
* The given address is already in use.
* EADDRNOTAVAIL
* Cannot assign requested address (unlikely)
*
* Assumptions:
* Interrupts are disabled
*
****************************************************************************/
static int uip_selectport(uint16_t 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. NOTE the following loop
* is assumed to terminate but could not if all 32000-4096+1 ports are
* in used (unlikely).
*/
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 (tcp_listener(htons(g_last_tcp_port)));
}
else
{
/* A port number has been supplied. Verify that no other TCP/IP
* connection is using this local port.
*/
if (tcp_listener(portno))
{
/* It is in use... return EADDRINUSE */
return -EADDRINUSE;
}
}
/* Return the selected or verified port number */
return portno;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_initialize()
*
* Description:
* Initialize the TCP/IP connection structures. Called only once and only
* from the UIP layer at start-up in normal user mode.
*
****************************************************************************/
void tcp_initialize(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 < CONFIG_NET_TCP_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: tcp_alloc()
*
* 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"
*
****************************************************************************/
FAR struct tcp_conn_s *tcp_alloc(void)
{
FAR struct tcp_conn_s *conn;
uip_lock_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 = uip_lock();
/* Return the entry from the head of the free list */
conn = (FAR struct tcp_conn_s *)dq_remfirst(&g_free_tcp_connections);
#ifndef CONFIG_NET_SOLINGER
/* Is the free list empty? */
if (!conn)
{
/* As a fall-back, check for connection structures which can be stalled.
*
* Search the active connection list for the oldest connection
* that is about to be closed anyway.
*/
FAR struct tcp_conn_s *tmp =
(FAR struct tcp_conn_s *)g_active_tcp_connections.head;
while (tmp)
{
nllvdbg("conn: %p state: %02x\n", tmp, tmp->tcpstateflags);
/* Is this connection in a state we can sacrifice. */
/* REVISIT: maybe we could check for SO_LINGER but it's buried
* in the socket layer.
*/
if (tmp->tcpstateflags == UIP_CLOSING ||
tmp->tcpstateflags == UIP_FIN_WAIT_1 ||
tmp->tcpstateflags == UIP_FIN_WAIT_2 ||
tmp->tcpstateflags == UIP_TIME_WAIT ||
tmp->tcpstateflags == UIP_LAST_ACK)
{
/* Yes.. 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 = (FAR struct tcp_conn_s *)tmp->node.flink;
}
/* Did we find a connection that we can re-use? */
if (conn != NULL)
{
nlldbg("Closing unestablished connection: %p\n", conn);
/* Yes... free it. This will remove the connection from the list
* of active connections and release all resources held by the
* connection.
*
* REVISIT: Could there be any higher level, socket interface
* that needs to be informed that we did this to them?
*
* Actually yes. When CONFIG_NET_SOLINGER is enabled there is a
* pending callback in netclose_disconnect waiting for getting
* woken up. Otherwise there's the callback too, but no one is
* waiting for it.
*/
tcp_free(conn);
/* Now there is guaranteed to be one free connection. Get it! */
conn = (FAR struct tcp_conn_s *)dq_remfirst(&g_free_tcp_connections);
}
}
#endif
uip_unlock(flags);
/* Mark the connection allocated */
if (conn)
{
memset(conn, 0, sizeof(struct tcp_conn_s));
conn->tcpstateflags = UIP_ALLOCATED;
}
return conn;
}
/****************************************************************************
* Name: tcp_free()
*
* Description:
* Free a connection structure that is no longer in use. This should be
* done by the implementation of close()
*
****************************************************************************/
void tcp_free(FAR struct tcp_conn_s *conn)
{
FAR struct uip_callback_s *cb;
FAR struct uip_callback_s *next;
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
FAR struct tcp_wrbuffer_s *wrbuffer;
#endif
uip_lock_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.
*/
DEBUGASSERT(conn->crefs == 0);
flags = uip_lock();
/* Free remaining callbacks, actually there should be only the close callback
* left.
*/
for (cb = conn->list; cb; cb = next)
{
next = cb->flink;
tcp_callbackfree(conn, cb);
}
/* 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_active_tcp_connections);
}
#ifdef CONFIG_NET_TCP_READAHEAD
/* Release any read-ahead buffers attached to the connection */
iob_free_queue(&conn->readahead);
#endif
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
/* Release any write buffers attached to the connection */
while ((wrbuffer = (struct tcp_wrbuffer_s *)sq_remfirst(&conn->write_q)) != NULL)
{
tcp_wrbuffer_release(wrbuffer);
}
while ((wrbuffer = (struct tcp_wrbuffer_s *)sq_remfirst(&conn->unacked_q)) != NULL)
{
tcp_wrbuffer_release(wrbuffer);
}
#endif
#ifdef CONFIG_NET_TCPBACKLOG
/* Remove any backlog attached to this connection */
if (conn->backlog)
{
tcp_backlogdestroy(conn);
}
/* If this connection is, itself, backlogged, then remove it from the
* parent connection's backlog list.
*/
if (conn->blparent)
{
tcp_backlogdelete(conn->blparent, conn);
}
#endif
/* Mark the connection available and put it into the free list */
conn->tcpstateflags = UIP_CLOSED;
dq_addlast(&conn->node, &g_free_tcp_connections);
uip_unlock(flags);
}
/****************************************************************************
* Name: tcp_active()
*
* Description:
* Find a connection structure that is the appropriate
* connection to be used with the provided TCP/IP header
*
* Assumptions:
* This function is called from UIP logic at interrupt level
*
****************************************************************************/
FAR struct tcp_conn_s *tcp_active(struct tcp_iphdr_s *buf)
{
FAR struct tcp_conn_s *conn = (struct tcp_conn_s *)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 = (FAR struct tcp_conn_s *)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).
*
****************************************************************************/
FAR struct tcp_conn_s *uip_nexttcpconn(FAR struct tcp_conn_s *conn)
{
if (!conn)
{
return (FAR struct tcp_conn_s *)g_active_tcp_connections.head;
}
else
{
return (FAR struct tcp_conn_s *)conn->node.flink;
}
}
/****************************************************************************
* Name: tcp_listener()
*
* Description:
* Given a local port number (in network byte order), find the TCP
* connection that listens on this this port.
*
* Primary uses: (1) to determine if a port number is available, (2) to
* To identify the socket that will accept new connections on a local port.
*
****************************************************************************/
FAR struct tcp_conn_s *tcp_listener(uint16_t portno)
{
FAR struct tcp_conn_s *conn;
int i;
/* Check if this port number is in use by any active UIP TCP connection */
for (i = 0; i < CONFIG_NET_TCP_CONNS; i++)
{
conn = &g_tcp_connections[i];
if (conn->tcpstateflags != UIP_CLOSED && conn->lport == portno)
{
/* The port number is in use, return the connection */
return conn;
}
}
return NULL;
}
/****************************************************************************
* Name: tcp_alloc_accept()
*
* Description:
* Called when uip_interrupt 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
*
****************************************************************************/
FAR struct tcp_conn_s *tcp_alloc_accept(FAR struct tcp_iphdr_s *buf)
{
FAR struct tcp_conn_s *conn = tcp_alloc();
if (conn)
{
/* Fill in the necessary fields for the new connection. */
conn->rto = UIP_RTO;
conn->timer = UIP_RTO;
conn->sa = 0;
conn->sv = 4;
conn->nrtx = 0;
conn->lport = buf->destport;
conn->rport = buf->srcport;
conn->mss = UIP_TCP_INITIAL_MSS;
uip_ipaddr_copy(conn->ripaddr, uip_ip4addr_conv(buf->srcipaddr));
conn->tcpstateflags = UIP_SYN_RCVD;
tcp_initsequence(conn->sndseq);
conn->unacked = 1;
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
conn->expired = 0;
conn->isn = 0;
conn->sent = 0;
#endif
/* rcvseq should be the seqno from the incoming packet + 1. */
memcpy(conn->rcvseq, buf->seqno, 4);
#ifdef CONFIG_NET_TCP_READAHEAD
/* Initialize the list of TCP read-ahead buffers */
IOB_QINIT(&conn->readahead);
#endif
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
/* Initialize the write buffer lists */
sq_init(&conn->write_q);
sq_init(&conn->unacked_q);
#endif
/* And, finally, put the connection structure into the active list.
* Interrupts should already be disabled in this context.
*/
dq_addlast(&conn->node, &g_active_tcp_connections);
}
return conn;
}
/****************************************************************************
* Name: tcp_bind()
*
* Description:
* This function implements the UIP specific parts of the standard TCP
* bind() operation.
*
* Return:
* 0 on success or -EADDRINUSE on failure
*
* Assumptions:
* This function is called from normal user level code.
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int tcp_bind(FAR struct tcp_conn_s *conn,
FAR const struct sockaddr_in6 *addr)
#else
int tcp_bind(FAR struct tcp_conn_s *conn,
FAR const struct sockaddr_in *addr)
#endif
{
uip_lock_t flags;
int port;
/* Verify or select a local port */
flags = uip_lock();
port = uip_selectport(ntohs(addr->sin_port));
uip_unlock(flags);
if (port < 0)
{
return port;
}
/* Save the local address in the connection structure. Note that the requested
* local IP address is saved but not used. At present, only a single network
* interface is supported, the IP address is not of importance.
*/
conn->lport = addr->sin_port;
#if 0 /* Not used */
#ifdef CONFIG_NET_IPv6
uip_ipaddr_copy(conn->lipaddr, addr->sin6_addr.in6_u.u6_addr16);
#else
uip_ipaddr_copy(conn->lipaddr, addr->sin_addr.s_addr);
#endif
#endif
return OK;
}
/****************************************************************************
* Name: tcp_connect
*
* 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 specified 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 tcp_connect().
*
* Assumptions:
* This function is called from normal user level code.
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int tcp_connect(FAR struct tcp_conn_s *conn,
FAR const struct sockaddr_in6 *addr)
#else
int tcp_connect(FAR struct tcp_conn_s *conn,
FAR const struct sockaddr_in *addr)
#endif
{
uip_lock_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 already been bound to a local port, then select
* one now.
*/
flags = uip_lock();
port = uip_selectport(ntohs(conn->lport));
uip_unlock(flags);
if (port < 0)
{
return port;
}
/* Initialize and return the connection structure, bind it to the port number */
conn->tcpstateflags = UIP_SYN_SENT;
tcp_initsequence(conn->sndseq);
conn->mss = UIP_TCP_INITIAL_MSS;
conn->unacked = 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_t)port);
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
conn->expired = 0;
conn->isn = 0;
conn->sent = 0;
#endif
/* 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);
#ifdef CONFIG_NET_TCP_READAHEAD
/* Initialize the list of TCP read-ahead buffers */
IOB_QINIT(&conn->readahead);
#endif
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
/* Initialize the TCP write buffer lists */
sq_init(&conn->write_q);
sq_init(&conn->unacked_q);
#endif
/* 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 = uip_lock();
dq_addlast(&conn->node, &g_active_tcp_connections);
uip_unlock(flags);
return OK;
}
#endif /* CONFIG_NET && CONFIG_NET_TCP */
