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Danger-alarm/SOFTWARE-FreeRTOS/Common/ethernet/lwIP/core/tcp.c

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2024-06-03 16:27:41 +08:00
/**
* @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 <adam@sics.se>
*
*/
#include <string.h>
#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/memp.h"
#include "lwip/snmp.h"
#include "lwip/tcp.h"
#if LWIP_TCP
/* Incremented every coarse grained timer shot (typically every 500 ms). */
u32_t tcp_ticks;
const 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 tcp_listen_pcbs;
/** List of all TCP PCBs that are in a state in which
* they accept or send data. */
struct tcp_pcb *tcp_active_pcbs;
/** List of all TCP PCBs in TIME-WAIT state */
struct tcp_pcb *tcp_tw_pcbs;
struct tcp_pcb *tcp_tmp_pcb;
static u8_t tcp_timer;
static u16_t tcp_new_port(void);
/**
* 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;
}
/**
* 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();
}
}
/**
* Closes the connection held by the PCB.
*
*/
err_t
tcp_close(struct tcp_pcb *pcb)
{
err_t err;
#if TCP_DEBUG
LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
tcp_debug_print_state(pcb->state);
#endif /* TCP_DEBUG */
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 **)&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;
snmp_inc_tcpattemptfails();
break;
case SYN_RCVD:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpattemptfails();
pcb->state = FIN_WAIT_1;
}
break;
case ESTABLISHED:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
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 *pcb)
{
u32_t seqno, ackno;
u16_t remote_port, local_port;
struct ip_addr remote_ip, local_ip;
#if LWIP_CALLBACK_API
void (* errf)(void *arg, err_t err);
#endif /* LWIP_CALLBACK_API */
void *errf_arg;
/* 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, &(pcb->local_ip));
ip_addr_set(&remote_ip, &(pcb->remote_ip));
local_port = pcb->local_port;
remote_port = pcb->remote_port;
#if LWIP_CALLBACK_API
errf = pcb->errf;
#endif /* LWIP_CALLBACK_API */
errf_arg = pcb->callback_arg;
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);
TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abort: sending RST\n"));
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 *pcb, struct ip_addr *ipaddr, u16_t port)
{
struct tcp_pcb *cpcb;
if (port == 0) {
port = tcp_new_port();
}
/* Check if the address already is in use. */
for(cpcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs;
cpcb != NULL; cpcb = cpcb->next) {
if (cpcb->local_port == port) {
if (ip_addr_isany(&(cpcb->local_ip)) ||
ip_addr_isany(ipaddr) ||
ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
return ERR_USE;
}
}
}
for(cpcb = tcp_active_pcbs;
cpcb != NULL; cpcb = cpcb->next) {
if (cpcb->local_port == port) {
if (ip_addr_isany(&(cpcb->local_ip)) ||
ip_addr_isany(ipaddr) ||
ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
return ERR_USE;
}
}
}
if (!ip_addr_isany(ipaddr)) {
pcb->local_ip = *ipaddr;
}
pcb->local_port = port;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port));
return ERR_OK;
}
#if LWIP_CALLBACK_API
static err_t
tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err)
{
(void)arg;
(void)pcb;
(void)err;
return ERR_ABRT;
}
#endif /* LWIP_CALLBACK_API */
/**
* Set the state of the connection to be LISTEN, which means that it
* is able to accept incoming connections. The protocol control block
* is reallocated in order to consume less memory. Setting the
* connection to LISTEN is an irreversible process.
*
*/
struct tcp_pcb *
tcp_listen(struct tcp_pcb *pcb)
{
struct tcp_pcb_listen *lpcb;
/* already listening? */
if (pcb->state == LISTEN) {
return pcb;
}
lpcb = memp_malloc(MEMP_TCP_PCB_LISTEN);
if (lpcb == NULL) {
return NULL;
}
lpcb->callback_arg = pcb->callback_arg;
lpcb->local_port = pcb->local_port;
lpcb->state = LISTEN;
lpcb->so_options = pcb->so_options;
lpcb->so_options |= SOF_ACCEPTCONN;
lpcb->ttl = pcb->ttl;
lpcb->tos = pcb->tos;
ip_addr_set(&lpcb->local_ip, &pcb->local_ip);
memp_free(MEMP_TCP_PCB, pcb);
#if LWIP_CALLBACK_API
lpcb->accept = tcp_accept_null;
#endif /* LWIP_CALLBACK_API */
TCP_REG(&tcp_listen_pcbs.listen_pcbs, lpcb);
return (struct tcp_pcb *)lpcb;
}
/**
* This function should be called by the application when it has
* processed the data. The purpose is to advertise a larger window
* when the data has been processed.
*
*/
void
tcp_recved(struct tcp_pcb *pcb, u16_t len)
{
if ((u32_t)pcb->rcv_wnd + len > TCP_WND) {
pcb->rcv_wnd = TCP_WND;
} else {
pcb->rcv_wnd += len;
}
if (!(pcb->flags & TF_ACK_DELAY) &&
!(pcb->flags & TF_ACK_NOW)) {
/*
* We send an ACK here (if one is not already pending, hence
* the above tests) as tcp_recved() implies that the application
* has processed some data, and so we can open the receiver's
* window to allow more to be transmitted. This could result in
* two ACKs being sent for each received packet in some limited cases
* (where the application is only receiving data, and is slow to
* process it) but it is necessary to guarantee that the sender can
* continue to transmit.
*/
tcp_ack(pcb);
}
else if (pcb->flags & TF_ACK_DELAY && pcb->rcv_wnd >= TCP_WND/2) {
/* If we can send a window update such that there is a full
* segment available in the window, do so now. This is sort of
* nagle-like in its goals, and tries to hit a compromise between
* sending acks each time the window is updated, and only sending
* window updates when a timer expires. The "threshold" used
* above (currently TCP_WND/2) can be tuned to be more or less
* aggressive */
tcp_ack_now(pcb);
}
LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n",
len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd));
}
/**
* A nastly hack featuring 'goto' statements that allocates a
* new TCP local port.
*/
static u16_t
tcp_new_port(void)
{
struct tcp_pcb *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 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 *)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 *pcb, struct ip_addr *ipaddr, u16_t port,
err_t (* connected)(void *arg, struct tcp_pcb *tpcb, err_t err))
{
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 = pcb->mss * 10;
pcb->state = SYN_SENT;
#if LWIP_CALLBACK_API
pcb->connected = connected;
#endif /* LWIP_CALLBACK_API */
TCP_REG(&tcp_active_pcbs, pcb);
snmp_inc_tcpactiveopens();
/* 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 *)&optdata, 4);
if (ret == ERR_OK) {
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 *pcb, *pcb2, *prev;
u32_t eff_wnd;
u8_t pcb_remove; /* flag if a PCB should be removed */
err_t err;
err = ERR_OK;
++tcp_ticks;
/* Steps through all of the active PCBs. */
prev = NULL;
pcb = tcp_active_pcbs;
if (pcb == NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
}
while (pcb != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED);
LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN);
LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT);
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. */
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"U16_F" pcb->rto %"U16_F"\n",
pcb->rtime, pcb->rto));
/* Double retransmission time-out unless we are trying to
* connect to somebody (i.e., we are in SYN_SENT). */
if (pcb->state != SYN_SENT) {
pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
}
/* 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));
/* 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 ((u32_t)(tcp_ticks - 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"));
}
}
/* Check if KEEPALIVE should be sent */
if((pcb->so_options & SOF_KEEPALIVE) && ((pcb->state == ESTABLISHED) || (pcb->state == CLOSE_WAIT))) {
if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keepalive + TCP_MAXIDLE) / TCP_SLOW_INTERVAL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n",
ip4_addr1(&pcb->remote_ip), ip4_addr2(&pcb->remote_ip),
ip4_addr3(&pcb->remote_ip), ip4_addr4(&pcb->remote_ip)));
tcp_abort(pcb);
}
else if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keepalive + pcb->keep_cnt * TCP_KEEPINTVL) / TCP_SLOW_INTERVAL) {
tcp_keepalive(pcb);
pcb->keep_cnt++;
}
}
/* 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 &&
(u32_t)tcp_ticks - 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 ((u32_t)(tcp_ticks - 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 ((u32_t)(tcp_ticks - 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) {
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;
}
TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
pcb2 = pcb->next;
memp_free(MEMP_TCP_PCB, pcb);
pcb = pcb2;
} else {
/* We check if we should poll the connection. */
++pcb->polltmr;
if (pcb->polltmr >= pcb->pollinterval) {
pcb->polltmr = 0;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
TCP_EVENT_POLL(pcb, err);
if (err == ERR_OK) {
tcp_output(pcb);
}
}
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 ((u32_t)(tcp_ticks - 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 *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 *seg)
{
u8_t count = 0;
struct tcp_seg *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 *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;
}
/**
* Sets the priority of a connection.
*
*/
void
tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
{
pcb->prio = prio;
}
#if TCP_QUEUE_OOSEQ
/**
* Returns a copy of the given TCP segment.
*
*/
struct tcp_seg *
tcp_seg_copy(struct tcp_seg *seg)
{
struct tcp_seg *cseg;
cseg = memp_malloc(MEMP_TCP_SEG);
if (cseg == NULL) {
return NULL;
}
memcpy((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg));
pbuf_ref(cseg->p);
return cseg;
}
#endif
#if LWIP_CALLBACK_API
static err_t
tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
{
arg = arg;
if (p != NULL) {
pbuf_free(p);
} else if (err == ERR_OK) {
return tcp_close(pcb);
}
return ERR_OK;
}
#endif /* LWIP_CALLBACK_API */
static void
tcp_kill_prio(u8_t prio)
{
struct tcp_pcb *pcb, *inactive;
u32_t inactivity;
u8_t mprio;
mprio = TCP_PRIO_MAX;
/* We kill the oldest active connection that has lower priority than
prio. */
inactivity = 0;
inactive = NULL;
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->prio <= prio &&
pcb->prio <= mprio &&
(u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
inactivity = tcp_ticks - pcb->tmr;
inactive = pcb;
mprio = pcb->prio;
}
}
if (inactive != NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
(void *)inactive, inactivity));
tcp_abort(inactive);
}
}
static void
tcp_kill_timewait(void)
{
struct tcp_pcb *pcb, *inactive;
u32_t inactivity;
inactivity = 0;
inactive = NULL;
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
inactivity = tcp_ticks - 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 *
tcp_alloc(u8_t prio)
{
struct tcp_pcb *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_prio(prio);
pcb = memp_malloc(MEMP_TCP_PCB);
}
}
if (pcb != NULL) {
memset(pcb, 0, sizeof(struct tcp_pcb));
pcb->prio = TCP_PRIO_NORMAL;
pcb->snd_buf = TCP_SND_BUF;
pcb->snd_queuelen = 0;
pcb->rcv_wnd = TCP_WND;
pcb->tos = 0;
pcb->ttl = TCP_TTL;
pcb->mss = TCP_MSS;
pcb->rto = 3000 / TCP_SLOW_INTERVAL;
pcb->sa = 0;
pcb->sv = 3000 / 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 = tcp_ticks;
pcb->polltmr = 0;
#if LWIP_CALLBACK_API
pcb->recv = tcp_recv_null;
#endif /* LWIP_CALLBACK_API */
/* Init KEEPALIVE timer */
pcb->keepalive = TCP_KEEPDEFAULT;
pcb->keep_cnt = 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 *
tcp_new(void)
{
return tcp_alloc(TCP_PRIO_NORMAL);
}
/*
* tcp_arg():
*
* Used to specify the argument that should be passed callback
* functions.
*
*/
void
tcp_arg(struct tcp_pcb *pcb, void *arg)
{
pcb->callback_arg = arg;
}
#if LWIP_CALLBACK_API
/**
* Used to specify the function that should be called when a TCP
* connection receives data.
*
*/
void
tcp_recv(struct tcp_pcb *pcb,
err_t (* recv)(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err))
{
pcb->recv = recv;
}
/**
* Used to specify the function that should be called when TCP data
* has been successfully delivered to the remote host.
*
*/
void
tcp_sent(struct tcp_pcb *pcb,
err_t (* sent)(void *arg, struct tcp_pcb *tpcb, u16_t len))
{
pcb->sent = sent;
}
/**
* Used to specify the function that should be called when a fatal error
* has occured on the connection.
*
*/
void
tcp_err(struct tcp_pcb *pcb,
void (* errf)(void *arg, err_t err))
{
pcb->errf = errf;
}
/**
* Used for specifying the function that should be called when a
* LISTENing connection has been connected to another host.
*
*/
void
tcp_accept(struct tcp_pcb *pcb,
err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err))
{
((struct tcp_pcb_listen *)pcb)->accept = accept;
}
#endif /* LWIP_CALLBACK_API */
/**
* Used to specify the function that should be called periodically
* from TCP. The interval is specified in terms of the TCP coarse
* timer interval, which is called twice a second.
*
*/
void
tcp_poll(struct tcp_pcb *pcb,
err_t (* poll)(void *arg, struct tcp_pcb *tpcb), u8_t interval)
{
#if LWIP_CALLBACK_API
pcb->poll = poll;
#endif /* LWIP_CALLBACK_API */
pcb->pollinterval = interval;
}
/**
* Purges a TCP PCB. Removes any buffered data and frees the buffer memory.
*
*/
void
tcp_pcb_purge(struct tcp_pcb *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 **pcblist, struct tcp_pcb *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 iss = 6510;
iss += tcp_ticks; /* XXX */
return iss;
}
#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
void
tcp_debug_print(struct tcp_hdr *tcphdr)
{
LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n"));
LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(TCP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n",
ntohs(tcphdr->src), ntohs(tcphdr->dest)));
LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n",
ntohl(tcphdr->seqno)));
LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n",
ntohl(tcphdr->ackno)));
LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" | |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"| %5"U16_F" | (hdrlen, flags (",
TCPH_HDRLEN(tcphdr),
TCPH_FLAGS(tcphdr) >> 5 & 1,
TCPH_FLAGS(tcphdr) >> 4 & 1,
TCPH_FLAGS(tcphdr) >> 3 & 1,
TCPH_FLAGS(tcphdr) >> 2 & 1,
TCPH_FLAGS(tcphdr) >> 1 & 1,
TCPH_FLAGS(tcphdr) & 1,
ntohs(tcphdr->wnd)));
tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
LWIP_DEBUGF(TCP_DEBUG, ("), win)\n"));
LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(TCP_DEBUG, ("| 0x%04"X16_F" | %5"U16_F" | (chksum, urgp)\n",
ntohs(tcphdr->chksum), ntohs(tcphdr->urgp)));
LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
}
void
tcp_debug_print_state(enum tcp_state s)
{
LWIP_DEBUGF(TCP_DEBUG, ("State: "));
switch (s) {
case CLOSED:
LWIP_DEBUGF(TCP_DEBUG, ("CLOSED\n"));
break;
case LISTEN:
LWIP_DEBUGF(TCP_DEBUG, ("LISTEN\n"));
break;
case SYN_SENT:
LWIP_DEBUGF(TCP_DEBUG, ("SYN_SENT\n"));
break;
case SYN_RCVD:
LWIP_DEBUGF(TCP_DEBUG, ("SYN_RCVD\n"));
break;
case ESTABLISHED:
LWIP_DEBUGF(TCP_DEBUG, ("ESTABLISHED\n"));
break;
case FIN_WAIT_1:
LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_1\n"));
break;
case FIN_WAIT_2:
LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_2\n"));
break;
case CLOSE_WAIT:
LWIP_DEBUGF(TCP_DEBUG, ("CLOSE_WAIT\n"));
break;
case CLOSING:
LWIP_DEBUGF(TCP_DEBUG, ("CLOSING\n"));
break;
case LAST_ACK:
LWIP_DEBUGF(TCP_DEBUG, ("LAST_ACK\n"));
break;
case TIME_WAIT:
LWIP_DEBUGF(TCP_DEBUG, ("TIME_WAIT\n"));
break;
}
}
void
tcp_debug_print_flags(u8_t flags)
{
if (flags & TCP_FIN) {
LWIP_DEBUGF(TCP_DEBUG, ("FIN "));
}
if (flags & TCP_SYN) {
LWIP_DEBUGF(TCP_DEBUG, ("SYN "));
}
if (flags & TCP_RST) {
LWIP_DEBUGF(TCP_DEBUG, ("RST "));
}
if (flags & TCP_PSH) {
LWIP_DEBUGF(TCP_DEBUG, ("PSH "));
}
if (flags & TCP_ACK) {
LWIP_DEBUGF(TCP_DEBUG, ("ACK "));
}
if (flags & TCP_URG) {
LWIP_DEBUGF(TCP_DEBUG, ("URG "));
}
if (flags & TCP_ECE) {
LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
}
if (flags & TCP_CWR) {
LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
}
}
void
tcp_debug_print_pcbs(void)
{
struct tcp_pcb *pcb;
LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n"));
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
pcb->local_port, pcb->remote_port,
pcb->snd_nxt, pcb->rcv_nxt));
tcp_debug_print_state(pcb->state);
}
LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n"));
for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
pcb->local_port, pcb->remote_port,
pcb->snd_nxt, pcb->rcv_nxt));
tcp_debug_print_state(pcb->state);
}
LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n"));
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
pcb->local_port, pcb->remote_port,
pcb->snd_nxt, pcb->rcv_nxt));
tcp_debug_print_state(pcb->state);
}
}
s16_t
tcp_pcbs_sane(void)
{
struct tcp_pcb *pcb;
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED);
LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN);
LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
}
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
}
return 1;
}
#endif /* TCP_DEBUG */
#endif /* LWIP_TCP */
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