www.pudn.com > TCPmodbushy.rar > tcp.c
/**
* @file
*
* Transmission Control Protocol for IP
*
* This file contains common functions for the TCP implementation, such as functinos
* for manipulating the data structures and the TCP timer functions. TCP functions
* related to input and output is found in tcp_in.c and tcp_out.c respectively.
*
*/
/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* 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.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Adam Dunkels
*
*/
#include
#include "o:/lwip/opt.h"
#include "o:/lwip/def.h"
#include "o:/lwip/mem.h"
#include "o:/lwip/memp.h"
#include "o:/lwip/tcp.h"
#if LWIP_TCP
/* Incremented every coarse grained timer shot
(typically every 500 ms, determined by TCP_COARSE_TIMEOUT). */
u32_t data tcp_ticks;
/*code u8_t tcp_backoff[13] =
{ 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};*/
/* The TCP PCB lists. */
/** List of all TCP PCBs in LISTEN state */
union tcp_listen_pcbs_t xdata tcp_listen_pcbs;
/** List of all TCP PCBs that are in a state in which
* they accept or send data. */
struct tcp_pcb xdata * xdata tcp_active_pcbs;
/** List of all TCP PCBs in TIME-WAIT state */
struct tcp_pcb xdata * xdata tcp_tw_pcbs;
struct tcp_pcb xdata * xdata tcp_tmp_pcb;
static u8_t data tcp_timer;
static u16_t tcp_new_port(void);
struct tcp_manager_block xdata Manager_Tcp_Table[MEMP_NUM_TCP_PCB];
/**
* Initializes the TCP layer.
*/
void
tcp_init(void)
{
/* Clear globals. */
tcp_listen_pcbs.listen_pcbs = NULL;
tcp_active_pcbs = NULL;
tcp_tw_pcbs = NULL;
tcp_tmp_pcb = NULL;
/* initialize timer */
tcp_ticks = 0;
tcp_timer = 0;
Init_Manager_Tcp_Table();
}
/******************************************************************************
* TCP open a port for listen
******************************************************************************/
void StartListen( void )
{
struct tcp_pcb_listen xdata *lpcb;
lpcb = memp_malloc(MEMP_TCP_PCB_LISTEN);
if (lpcb == NULL) {
return;
}
lpcb->local_port = TCP_LOCAL_PORT;
lpcb->state = LISTEN;
TCP_REG(&tcp_listen_pcbs.listen_pcbs, lpcb);
return;
}
/******************************************************************************
* Close a port for listen
******************************************************************************/
void StopListen( void )
{
if( tcp_listen_pcbs.listen_pcbs != NULL )
{
struct tcp_pcb xdata *tmp;
tmp = tcp_listen_pcbs.pcbs;
tcp_pcb_remove((struct tcp_pcb xdata * xdata *)&tcp_listen_pcbs.pcbs, tcp_listen_pcbs.pcbs);
memp_free(MEMP_TCP_PCB_LISTEN, tmp);
}
}
/******************************************************************************
* TBOX as a Master send data should create LINK if no have Links
* NULL: create failed
******************************************************************************/
struct tcp_pcb xdata* ConnectedDest( u16_t SelfPort, u32_t DestIP, u16_t DestPor )
{
struct tcp_pcb xdata* Tmp;
#ifdef TESTDEBUG
test[9]++;
#endif
Tmp = tcp_new();
if( Tmp != NULL)
{
if( tcp_bind( Tmp, SelfPort ) == ERR_OK )
{
struct ip_addr xdata ipDestIP;
ipDestIP.addr = DestIP;
if( tcp_connect( Tmp, (struct ip_addr xdata *)&ipDestIP, DestPor) == ERR_OK )
return Tmp;
}
tcp_close(Tmp);
}
}
/******************************************************************************
* TBOX as a Master send data should create LINK if no have Links
* NULL: create failed
******************************************************************************/
err_t SendTcpDATA( struct tcp_pcb xdata* pTcpLINK, struct MEMB xdata *pMemb )
{
//struct pbuf xdata *p
u16_t len;
struct MEMB xdata *Tmp;
Tmp = pMemb;
len = 0;
while( Tmp != NULL )
{
len += Tmp->size;
Tmp = Tmp->link;
}
if(pTcpLINK->state == ESTABLISHED ||
pTcpLINK->state == CLOSE_WAIT ||
pTcpLINK->state == SYN_SENT ||
pTcpLINK->state == SYN_RCVD) {
if ( len > 0) {
if( tcp_enqueue(pTcpLINK, (void xdata *)pMemb, len, 0, 1, NULL, 0) == ERR_OK ) {
tcp_output(pTcpLINK);
return ERR_OK;
}
else
{
#ifdef TESTDEBUG
test[6]++;
#endif
}
}
} else {
#ifdef TESTDEBUG
test[4]++;
#endif
return ERR_CONN;
}
}
/******************************************************************************
* Init TCP LINK TABLE
******************************************************************************/
void Init_Manager_Tcp_Table( void )
{
u8_t i;
for( i=0; iunsent != NULL )
||( Manager_Tcp_Table[i].pPointTcp_Pcb->unacked != NULL ) )
return 1;
}
}
return 0;
}
/**
* Called periodically to dispatch TCP timers.
*
*/
void tcp_tmr(void)
{
/* Call tcp_fasttmr() every 250 ms */
tcp_fasttmr();
if (++tcp_timer & 1) {
/* Call tcp_tmr() every 500 ms, i.e., every other timer
tcp_tmr() is called. */
tcp_slowtmr();
}
}
void tcp_close_AllLink( void )
{
struct tcp_pcb xdata *pcb;
pcb = tcp_active_pcbs;
while (pcb != NULL) {
/* this connection must be aborted */
struct tcp_pcb xdata *next = pcb->next;
tcp_abort(pcb);
pcb = next;
}
}
/**
* Closes the connection held by the PCB.
*
*/
err_t tcp_close(struct tcp_pcb xdata *pcb)
{
err_t err;
RemoveAItemFromTable( pcb );
switch (pcb->state) {
case CLOSED:
/* Closing a pcb in the CLOSED state might seem erroneous,
* however, it is in this state once allocated and as yet unused
* and the user needs some way to free it should the need arise.
* Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
* or for a pcb that has been used and then entered the CLOSED state
* is erroneous, but this should never happen as the pcb has in those cases
* been freed, and so any remaining handles are bogus. */
err = ERR_OK;
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case LISTEN:
err = ERR_OK;
tcp_pcb_remove((struct tcp_pcb xdata * xdata *)&tcp_listen_pcbs.pcbs, pcb);
memp_free(MEMP_TCP_PCB_LISTEN, pcb);
pcb = NULL;
break;
case SYN_SENT:
err = ERR_OK;
tcp_pcb_remove(&tcp_active_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case SYN_RCVD:
case ESTABLISHED:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
pcb->state = LAST_ACK;
}
break;
default:
/* Has already been closed, do nothing. */
err = ERR_OK;
pcb = NULL;
break;
}
if (pcb != NULL && err == ERR_OK) {
err = tcp_output(pcb);
}
return err;
}
/**
* Aborts a connection by sending a RST to the remote host and deletes
* the local protocol control block. This is done when a connection is
* killed because of shortage of memory.
*
*/
void
tcp_abort(struct tcp_pcb xdata *pcb)
{
u32_t seqno, ackno;
u16_t remote_port, local_port;
struct ip_addr xdata remote_ip, local_ip;
RemoveAItemFromTable( pcb );
/* Figure out on which TCP PCB list we are, and remove us. If we
are in an active state, call the receive function associated with
the PCB with a NULL argument, and send an RST to the remote end. */
if (pcb->state == TIME_WAIT) {
tcp_pcb_remove(&tcp_tw_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
} else {
seqno = pcb->snd_nxt;
ackno = pcb->rcv_nxt;
ip_addr_set(&local_ip, &(netif->ip_addr));
ip_addr_set(&remote_ip, &(pcb->remote_ip));
local_port = pcb->local_port;
remote_port = pcb->remote_port;
tcp_pcb_remove(&tcp_active_pcbs, pcb);
if (pcb->unacked != NULL) {
tcp_segs_free(pcb->unacked);
}
if (pcb->unsent != NULL) {
tcp_segs_free(pcb->unsent);
}
#if TCP_QUEUE_OOSEQ
if (pcb->ooseq != NULL) {
tcp_segs_free(pcb->ooseq);
}
#endif /* TCP_QUEUE_OOSEQ */
memp_free(MEMP_TCP_PCB, pcb);
/******************************************************************************
add err( TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT) )
******************************************************************************/
// sending RST
tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
}
}
/**
* Binds the connection to a local portnumber and IP address. If the
* IP address is not given (i.e., ipaddr == NULL), the IP address of
* the outgoing network interface is used instead.
*
*/
err_t tcp_bind(struct tcp_pcb xdata *pcb, u16_t port)
{
struct tcp_pcb xdata *cpcb;
if (port == 0) {
port = tcp_new_port();
}
/* Check if the address already is in use. */
for(cpcb = (struct tcp_pcb xdata *)tcp_listen_pcbs.pcbs; cpcb != NULL; cpcb = cpcb->next) {
if (cpcb->local_port == port) {
return ERR_USE;
}
}
for(cpcb = tcp_active_pcbs; cpcb != NULL; cpcb = cpcb->next) {
if (cpcb->local_port == port) {
return ERR_USE;
}
}
pcb->local_port = port;
return ERR_OK;
}
/**
* A nastly hack featuring 'goto' statements that allocates a
* new TCP local port.
*/
static u16_t
tcp_new_port(void)
{
struct tcp_pcb xdata *pcb;
#ifndef TCP_LOCAL_PORT_RANGE_START
#define TCP_LOCAL_PORT_RANGE_START 4096
#define TCP_LOCAL_PORT_RANGE_END 0x7fff
#endif
static u16_t data port = TCP_LOCAL_PORT_RANGE_START;
again:
if (++port > TCP_LOCAL_PORT_RANGE_END) {
port = TCP_LOCAL_PORT_RANGE_START;
}
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->local_port == port) {
goto again;
}
}
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->local_port == port) {
goto again;
}
}
for(pcb = (struct tcp_pcb xdata *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->local_port == port) {
goto again;
}
}
return port;
}
/**
* Connects to another host. The function given as the "connected"
* argument will be called when the connection has been established.
*
*/
err_t
tcp_connect(struct tcp_pcb xdata *pcb, struct ip_addr xdata *ipaddr, u16_t port)
{
u32_t optdata;
err_t ret;
u32_t iss;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port));
if (ipaddr != NULL) {
pcb->remote_ip = *ipaddr;
} else {
return ERR_VAL;
}
pcb->remote_port = port;
if (pcb->local_port == 0) {
pcb->local_port = tcp_new_port();
}
iss = tcp_next_iss();
pcb->rcv_nxt = 0;
pcb->snd_nxt = iss;
pcb->lastack = iss - 1;
pcb->snd_lbb = iss - 1;
// pcb->rcv_wnd = TCP_WND;
pcb->snd_wnd = TCP_WND;
pcb->mss = TCP_MSS;
pcb->cwnd = 1;
pcb->ssthresh = TCP_MSS * 10;//pcb->mss*10
pcb->state = SYN_SENT;
TCP_REG(&tcp_active_pcbs, pcb);
/* Build an MSS option */
optdata = htonl(((u32_t)2 << 24) |
((u32_t)4 << 16) |
(((u32_t)pcb->mss / 256) << 8) |
(pcb->mss & 255));
ret = tcp_enqueue(pcb, NULL, 0, TCP_SYN, 0, (u8_t xdata *)&optdata, 4);
if (ret == ERR_OK) {
AddAItemToTable(pcb);
tcp_output(pcb);
}
return ret;
}
/**
* Called every 500 ms and implements the retransmission timer and the timer that
* removes PCBs that have been in TIME-WAIT for enough time. It also increments
* various timers such as the inactivity timer in each PCB.
*/
void
tcp_slowtmr(void)
{
struct tcp_pcb xdata *pcb;
struct tcp_pcb xdata *pcb2;
struct tcp_pcb xdata *prev;
u32_t eff_wnd;
u8_t pcb_remove; /* flag if a PCB should be removed */
err_t err;
err = ERR_OK;
++tcp_ticks;
/* add account TIME */
pcb = tcp_active_pcbs;
while( pcb != NULL )
{
if( ( pcb->rttest != 0)&&( pcb->rttest != 0xff ) )
pcb->rttest++;
if( pcb->tmr != 0xff )
pcb->tmr++;
pcb = pcb->next;
}
pcb = tcp_tw_pcbs;
while( pcb != NULL )
{
if( ( pcb->rttest != 0)&&( pcb->rttest != 0xff ) )
pcb->rttest++;
if( pcb->tmr != 0xff )
pcb->tmr++;
pcb = pcb->next;
}
/* Steps through all of the active PCBs. */
prev = NULL;
pcb = tcp_active_pcbs;
while (pcb != NULL) {
pcb_remove = 0;
if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
++pcb_remove;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
}
else if (pcb->nrtx == TCP_MAXRTX) {
++pcb_remove;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
} else {
++pcb->rtime;
if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) {
/* Time for a retransmission. */
/* Double retransmission time-out unless we are trying to
* connect to somebody (i.e., we are in SYN_SENT). */
if (pcb->state != SYN_SENT) {
if( pcb->rto <= (3000/TCP_SLOW_INTERVAL) )
pcb->rto = pcb->rto + 1;
}
/* Reduce congestion window and ssthresh. */
eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
pcb->ssthresh = eff_wnd >> 1;
if (pcb->ssthresh < pcb->mss) {
pcb->ssthresh = pcb->mss * 2;
}
pcb->cwnd = pcb->mss;
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F" ssthresh %"U16_F"\n",
pcb->cwnd, pcb->ssthresh));
#ifdef TESTDEBUG
test[7]++;
#endif
/* The following needs to be called AFTER cwnd is set to one mss - STJ */
tcp_rexmit_rto(pcb);
}
}
/* Check if this PCB has stayed too long in FIN-WAIT-2 */
if (pcb->state == FIN_WAIT_2) {
if ( pcb->tmr > TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL ) {
++pcb_remove;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
}
}
/* If this PCB has queued out of sequence data, but has been
inactive for too long, will drop the data (it will eventually
be retransmitted). */
#if TCP_QUEUE_OOSEQ
if ( (pcb->ooseq != NULL) &&
(pcb->tmr >= pcb->rto * TCP_OOSEQ_TIMEOUT) ) {
tcp_segs_free(pcb->ooseq);
pcb->ooseq = NULL;
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n"));
}
#endif /* TCP_QUEUE_OOSEQ */
/* Check if this PCB has stayed too long in SYN-RCVD */
if (pcb->state == SYN_RCVD) {
if ( pcb->tmr > TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL ) {
++pcb_remove;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n"));
}
}
/* Check if this PCB has stayed too long in LAST-ACK */
if (pcb->state == LAST_ACK) {
if ( pcb->tmr > 2 * TCP_MSL / TCP_SLOW_INTERVAL ) {
++pcb_remove;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n"));
}
}
/* If the PCB should be removed, do it. */
if (pcb_remove) {
RemoveAItemFromTable( pcb );
tcp_pcb_purge(pcb);
/* Remove PCB from tcp_active_pcbs list. */
if (prev != NULL) {
LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
prev->next = pcb->next;
} else {
/* This PCB was the first. */
LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb);
tcp_active_pcbs = pcb->next;
}
/******************************************************************************
add err infor( TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT), you socket bei yizhou )
******************************************************************************/
pcb2 = pcb->next;
memp_free(MEMP_TCP_PCB, pcb);
pcb = pcb2;
} else {
prev = pcb;
pcb = pcb->next;
}
}
/* Steps through all of the TIME-WAIT PCBs. */
prev = NULL;
pcb = tcp_tw_pcbs;
while (pcb != NULL) {
LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
pcb_remove = 0;
/* Check if this PCB has stayed long enough in TIME-WAIT */
if ( pcb->tmr > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
++pcb_remove;
}
/* If the PCB should be removed, do it. */
if (pcb_remove) {
tcp_pcb_purge(pcb);
/* Remove PCB from tcp_tw_pcbs list. */
if (prev != NULL) {
LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
prev->next = pcb->next;
} else {
/* This PCB was the first. */
LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb);
tcp_tw_pcbs = pcb->next;
}
pcb2 = pcb->next;
memp_free(MEMP_TCP_PCB, pcb);
pcb = pcb2;
} else {
prev = pcb;
pcb = pcb->next;
}
}
}
/**
* Is called every TCP_FAST_INTERVAL (250 ms) and sends delayed ACKs.
*/
void
tcp_fasttmr(void)
{
struct tcp_pcb xdata *pcb;
/* send delayed ACKs */
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->flags & TF_ACK_DELAY) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n"));
tcp_ack_now(pcb);
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
}
}
}
/**
* Deallocates a list of TCP segments (tcp_seg structures).
*
*/
u8_t
tcp_segs_free(struct tcp_seg xdata *seg)
{
u8_t count = 0;
struct tcp_seg xdata *next;
while (seg != NULL) {
next = seg->next;
count += tcp_seg_free(seg);
seg = next;
}
return count;
}
/**
* Frees a TCP segment.
*
*/
u8_t
tcp_seg_free(struct tcp_seg xdata *seg)
{
u8_t count = 0;
if (seg != NULL) {
if (seg->p != NULL) {
count = pbuf_free(seg->p);
#if TCP_DEBUG
seg->p = NULL;
#endif /* TCP_DEBUG */
}
memp_free(MEMP_TCP_SEG, seg);
}
return count;
}
#if TCP_QUEUE_OOSEQ
/**
* Returns a copy of the given TCP segment.
*
*/
struct tcp_seg xdata *
tcp_seg_copy(struct tcp_seg xdata *seg)
{
struct tcp_seg xdata *cseg;
cseg = memp_malloc(MEMP_TCP_SEG);
if (cseg == NULL) {
return NULL;
}
memcpy((u8_t xdata *)cseg, (const u8_t xdata *)seg, sizeof(struct tcp_seg));
pbuf_ref(cseg->p);
return cseg;
}
#endif
/******************************************************************************
* kill activePCB must be a oldest and unactive time highe 12S
******************************************************************************/
#define KILL_UNACTIVE_PCB_TIME_LEVEL (15000/TCP_SLOW_INTERVAL) /*12S*/
static void
tcp_kill_oldest_active(void)
{
struct tcp_pcb xdata *pcb;
struct tcp_pcb xdata *inactive;
u8_t inactivity;
/* We kill the oldest active connection that has lower priority than
prio. */
inactivity = KILL_UNACTIVE_PCB_TIME_LEVEL;
inactive = NULL;
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
if ( pcb->tmr >= inactivity ) {
inactivity = pcb->tmr;
inactive = pcb;
}
}
if (inactive != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_oldest_active: killing oldest PCB %p (%"S32_F")\n",
(void *)inactive, inactivity));
tcp_abort(inactive);
}
}
static void
tcp_kill_timewait(void)
{
struct tcp_pcb xdata *pcb;
struct tcp_pcb xdata *inactive;
u8_t inactivity;
inactivity = 0;
inactive = NULL;
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
if ( pcb->tmr >= inactivity) {
inactivity = pcb->tmr;
inactive = pcb;
}
}
if (inactive != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n",
(void *)inactive, inactivity));
tcp_abort(inactive);
}
}
struct tcp_pcb xdata*
tcp_alloc(void)
{
struct tcp_pcb xdata *pcb;
u32_t iss;
pcb = memp_malloc(MEMP_TCP_PCB);
if (pcb == NULL) {
/* Try killing oldest connection in TIME-WAIT. */
LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
tcp_kill_timewait();
pcb = memp_malloc(MEMP_TCP_PCB);
if (pcb == NULL) {
tcp_kill_oldest_active();
pcb = memp_malloc(MEMP_TCP_PCB);
}
}
if (pcb != NULL) {
memset(pcb, 0, sizeof(struct tcp_pcb));
// pcb->snd_buf = TCP_SND_BUF;
pcb->snd_queuelen = 0;
// pcb->rcv_wnd = TCP_WND;
pcb->mss = TCP_MSS;
pcb->rto = 1500 / TCP_SLOW_INTERVAL;
pcb->rtime = 0;
pcb->cwnd = 1;
iss = tcp_next_iss();
pcb->snd_wl2 = iss;
pcb->snd_nxt = iss;
pcb->snd_max = iss;
pcb->lastack = iss;
pcb->snd_lbb = iss;
pcb->tmr = 0;
}
return pcb;
}
/**
* Creates a new TCP protocol control block but doesn't place it on
* any of the TCP PCB lists.
*
* @internal: Maybe there should be a idle TCP PCB list where these
* PCBs are put on. We can then implement port reservation using
* tcp_bind(). Currently, we lack this (BSD socket type of) feature.
*/
struct tcp_pcb xdata*
tcp_new(void)
{
return tcp_alloc();
}
/**
* Purges a TCP PCB. Removes any buffered data and frees the buffer memory.
*
*/
void
tcp_pcb_purge(struct tcp_pcb xdata *pcb)
{
if (pcb->state != CLOSED &&
pcb->state != TIME_WAIT &&
pcb->state != LISTEN) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
if (pcb->unsent != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
}
if (pcb->unacked != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
}
#if TCP_QUEUE_OOSEQ /* LW */
if (pcb->ooseq != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
}
tcp_segs_free(pcb->ooseq);
pcb->ooseq = NULL;
#endif /* TCP_QUEUE_OOSEQ */
tcp_segs_free(pcb->unsent);
tcp_segs_free(pcb->unacked);
pcb->unacked = pcb->unsent = NULL;
}
}
/**
* Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.
*
*/
void
tcp_pcb_remove(struct tcp_pcb xdata * xdata *pcblist, struct tcp_pcb xdata *pcb)
{
TCP_RMV(pcblist, pcb);
tcp_pcb_purge(pcb);
/* if there is an outstanding delayed ACKs, send it */
if (pcb->state != TIME_WAIT &&
pcb->state != LISTEN &&
pcb->flags & TF_ACK_DELAY) {
pcb->flags |= TF_ACK_NOW;
tcp_output(pcb);
}
pcb->state = CLOSED;
LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane());
}
/**
* Calculates a new initial sequence number for new connections.
*
*/
u32_t
tcp_next_iss(void)
{
static u32_t data iss = 6510;
iss += tcp_ticks; /* XXX */
return iss;
}
#endif /* LWIP_TCP */