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/*

 * 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>

 *

 */

#ifndef __LWIP_TCP_H__

#define __LWIP_TCP_H__

#include "lwip/sys.h"

#include "lwip/mem.h"

#include "lwip/pbuf.h"

#include "lwip/opt.h"

#include "lwip/ip.h"

#include "lwip/icmp.h"

#include "lwip/err.h"

struct tcp_pcb;

/* Functions for interfacing with TCP: */

/* Lower layer interface to TCP: */

void             tcp_init    (void);  /* Must be called first to

           initialize TCP. */

void             tcp_tmr     (void);  /* Must be called every

           TCP_TMR_INTERVAL

           ms. (Typically 250 ms). */

/* Application program's interface: */

struct tcp_pcb * tcp_new     (void);

struct tcp_pcb * tcp_alloc   (u8_t prio);

void             tcp_arg     (struct tcp_pcb *pcb, void *arg);

void             tcp_accept  (struct tcp_pcb *pcb,

            err_t (* accept)(void *arg, struct tcp_pcb *newpcb,

                 err_t err));

void             tcp_recv    (struct tcp_pcb *pcb,

            err_t (* recv)(void *arg, struct tcp_pcb *tpcb,

          struct pbuf *p, err_t err));

void             tcp_sent    (struct tcp_pcb *pcb,

            err_t (* sent)(void *arg, struct tcp_pcb *tpcb,

               u16_t len));

void             tcp_poll    (struct tcp_pcb *pcb,

            err_t (* poll)(void *arg, struct tcp_pcb *tpcb),

            u8_t interval);

void             tcp_err     (struct tcp_pcb *pcb,

            void (* err)(void *arg, err_t err));

#define          tcp_mss(pcb)      ((pcb)->mss)

#define          tcp_sndbuf(pcb)   ((pcb)->snd_buf)

void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);

err_t            tcp_bind    (struct tcp_pcb *pcb, struct ip_addr *ipaddr,

            u16_t port);

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));

struct tcp_pcb * tcp_listen  (struct tcp_pcb *pcb);

void             tcp_abort   (struct tcp_pcb *pcb);

err_t            tcp_close   (struct tcp_pcb *pcb);

err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,

            u8_t copy);

void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);

#define TCP_PRIO_MIN    1

#define TCP_PRIO_NORMAL 64

#define TCP_PRIO_MAX    127

/* It is also possible to call these two functions at the right

   intervals (instead of calling tcp_tmr()). */

void             tcp_slowtmr (void);

void             tcp_fasttmr (void);

/* Only used by IP to pass a TCP segment to TCP: */

void             tcp_input   (struct pbuf *p, struct netif *inp);

/* Used within the TCP code only: */

err_t            tcp_output  (struct tcp_pcb *pcb);

void             tcp_rexmit  (struct tcp_pcb *pcb);

void             tcp_rexmit_rto  (struct tcp_pcb *pcb);

#define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)

#define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)

#define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)

#define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)

/* is b<=a<=c? */

#if 0 /* see bug #10548 */

#define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))

#endif

#define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))

#define TCP_FIN 0x01U

#define TCP_SYN 0x02U

#define TCP_RST 0x04U

#define TCP_PSH 0x08U

#define TCP_ACK 0x10U

#define TCP_URG 0x20U

#define TCP_ECE 0x40U

#define TCP_CWR 0x80U

#define TCP_FLAGS 0x3fU

/* Length of the TCP header, excluding options. */

#define TCP_HLEN 20

#ifndef TCP_TMR_INTERVAL

#define TCP_TMR_INTERVAL       250  /* The TCP timer interval in

                                       milliseconds. */

#endif /* TCP_TMR_INTERVAL */

#ifndef TCP_FAST_INTERVAL

#define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in

                                       milliseconds */

#endif /* TCP_FAST_INTERVAL */

#ifndef TCP_SLOW_INTERVAL

#define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in

                                       milliseconds */

#endif /* TCP_SLOW_INTERVAL */

#define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */

#define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */

#define TCP_OOSEQ_TIMEOUT        6 /* x RTO */

#define TCP_MSL 60000  /* The maximum segment lifetime in microseconds */

/*

 * User-settable options (used with setsockopt).

 */

#define TCP_NODELAY        0x01    /* don't delay send to coalesce packets */

#define TCP_KEEPALIVE  0x02    /* send KEEPALIVE probes when idle for pcb->keepalive miliseconds */

/* Keepalive values */

#define  TCP_KEEPDEFAULT   7200000                       /* KEEPALIVE timer in miliseconds */

#define  TCP_KEEPINTVL     75000                         /* Time between KEEPALIVE probes in miliseconds */

#define  TCP_KEEPCNT       9                             /* Counter for KEEPALIVE probes */

#define  TCP_MAXIDLE       TCP_KEEPCNT * TCP_KEEPINTVL   /* Maximum KEEPALIVE probe time */

#ifdef PACK_STRUCT_USE_INCLUDES

#  include "arch/bpstruct.h"

#endif

PACK_STRUCT_BEGIN

struct tcp_hdr {

  PACK_STRUCT_FIELD(u16_t src);

  PACK_STRUCT_FIELD(u16_t dest);

  PACK_STRUCT_FIELD(u32_t seqno);

  PACK_STRUCT_FIELD(u32_t ackno);

  PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);

  PACK_STRUCT_FIELD(u16_t wnd);

  PACK_STRUCT_FIELD(u16_t chksum);

  PACK_STRUCT_FIELD(u16_t urgp);

} PACK_STRUCT_STRUCT;

PACK_STRUCT_END

#ifdef PACK_STRUCT_USE_INCLUDES

#  include "arch/epstruct.h"

#endif

#define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)

#define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)

#define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)

#define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))

#define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))

#define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons((ntohs((phdr)->_hdrlen_rsvd_flags) & ~TCP_FLAGS) | (flags))

#define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (flags))

#define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )

#define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & TCP_FIN || \

          TCPH_FLAGS((seg)->tcphdr) & TCP_SYN)? 1: 0))

enum tcp_state {

  CLOSED      = 0,

  LISTEN      = 1,

  SYN_SENT    = 2,

  SYN_RCVD    = 3,

  ESTABLISHED = 4,

  FIN_WAIT_1  = 5,

  FIN_WAIT_2  = 6,

  CLOSE_WAIT  = 7,

  CLOSING     = 8,

  LAST_ACK    = 9,

  TIME_WAIT   = 10

};

/* the TCP protocol control block */

struct tcp_pcb {

/** common PCB members */

  IP_PCB;

/** protocol specific PCB members */

  struct tcp_pcb *next; /* for the linked list */

  enum tcp_state state; /* TCP state */

  u8_t prio;

  void *callback_arg;

  u16_t local_port;

  u16_t remote_port;

  u8_t flags;

#define TF_ACK_DELAY (u8_t)0x01U   /* Delayed ACK. */

#define TF_ACK_NOW   (u8_t)0x02U   /* Immediate ACK. */

#define TF_INFR      (u8_t)0x04U   /* In fast recovery. */

#define TF_RESET     (u8_t)0x08U   /* Connection was reset. */

#define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */

#define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */

#define TF_NODELAY   (u8_t)0x40U   /* Disable Nagle algorithm */

  /* receiver variables */

  u32_t rcv_nxt;   /* next seqno expected */

  u16_t rcv_wnd;   /* receiver window */

  /* Timers */

  u32_t tmr;

  u8_t polltmr, pollinterval;

  /* Retransmission timer. */

  u16_t rtime;

  u16_t mss;   /* maximum segment size */

  /* RTT (round trip time) estimation variables */

  u32_t rttest; /* RTT estimate in 500ms ticks */

  u32_t rtseq;  /* sequence number being timed */

  s16_t sa, sv; /* @todo document this */

  u16_t rto;    /* retransmission time-out */

  u8_t nrtx;    /* number of retransmissions */

  /* fast retransmit/recovery */

  u32_t lastack; /* Highest acknowledged seqno. */

  u8_t dupacks;

  /* congestion avoidance/control variables */

  u16_t cwnd;

  u16_t ssthresh;

  /* sender variables */

  u32_t snd_nxt,       /* next seqno to be sent */

    snd_max,       /* Highest seqno sent. */

    snd_wnd,       /* sender window */

    snd_wl1, snd_wl2, /* Sequence and acknowledgement numbers of last

       window update. */

    snd_lbb;       /* Sequence number of next byte to be buffered. */

  u16_t acked;

  u16_t snd_buf;   /* Available buffer space for sending (in bytes). */

  u8_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */

  /* These are ordered by sequence number: */

  struct tcp_seg *unsent;   /* Unsent (queued) segments. */

  struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */

#if TCP_QUEUE_OOSEQ  

  struct tcp_seg *ooseq;    /* Received out of sequence segments. */

#endif /* TCP_QUEUE_OOSEQ */

#if LWIP_CALLBACK_API

  /* Function to be called when more send buffer space is available. */

  err_t (* sent)(void *arg, struct tcp_pcb *pcb, u16_t space);

  /* Function to be called when (in-sequence) data has arrived. */

  err_t (* recv)(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);

  /* Function to be called when a connection has been set up. */

  err_t (* connected)(void *arg, struct tcp_pcb *pcb, err_t err);

  /* Function to call when a listener has been connected. */

  err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err);

  /* Function which is called periodically. */

  err_t (* poll)(void *arg, struct tcp_pcb *pcb);

  /* Function to be called whenever a fatal error occurs. */

  void (* errf)(void *arg, err_t err);

#endif /* LWIP_CALLBACK_API */

  /* idle time before KEEPALIVE is sent */

  u32_t keepalive;

  /* KEEPALIVE counter */

  u8_t keep_cnt;

};

struct tcp_pcb_listen {

/* Common members of all PCB types */

  IP_PCB;

/* Protocol specific PCB members */

  struct tcp_pcb_listen *next;   /* for the linked list */

  /* Even if state is obviously LISTEN this is here for

   * field compatibility with tpc_pcb to which it is cast sometimes

   * Until a cleaner solution emerges this is here.FIXME

   */

  enum tcp_state state;   /* TCP state */

  u8_t prio;

  void *callback_arg;

  u16_t local_port;

#if LWIP_CALLBACK_API

  /* Function to call when a listener has been connected. */

  err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err);

#endif /* LWIP_CALLBACK_API */

};

#if LWIP_EVENT_API

enum lwip_event {

  LWIP_EVENT_ACCEPT,

  LWIP_EVENT_SENT,

  LWIP_EVENT_RECV,

  LWIP_EVENT_CONNECTED,

  LWIP_EVENT_POLL,

  LWIP_EVENT_ERR

};

err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,

         enum lwip_event,

         struct pbuf *p,

         u16_t size,

         err_t err);

#define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\

                LWIP_EVENT_ACCEPT, NULL, 0, err)

#define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\

                   LWIP_EVENT_SENT, NULL, space, ERR_OK)

#define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\

                LWIP_EVENT_RECV, (p), 0, (err))

#define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\

                LWIP_EVENT_CONNECTED, NULL, 0, (err))

#define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\

                LWIP_EVENT_POLL, NULL, 0, ERR_OK)

#define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \

                LWIP_EVENT_ERR, NULL, 0, (err))

#else /* LWIP_EVENT_API */

#define TCP_EVENT_ACCEPT(pcb,err,ret)     \

                        if((pcb)->accept != NULL) \

                        (ret = (pcb)->accept((pcb)->callback_arg,(pcb),(err)))

#define TCP_EVENT_SENT(pcb,space,ret) \

                        if((pcb)->sent != NULL) \

                        (ret = (pcb)->sent((pcb)->callback_arg,(pcb),(space)))

#define TCP_EVENT_RECV(pcb,p,err,ret) \

                        if((pcb)->recv != NULL) \

                        { ret = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err)); } else { \

                          if (p) pbuf_free(p); }

#define TCP_EVENT_CONNECTED(pcb,err,ret) \

                        if((pcb)->connected != NULL) \

                        (ret = (pcb)->connected((pcb)->callback_arg,(pcb),(err)))

#define TCP_EVENT_POLL(pcb,ret) \

                        if((pcb)->poll != NULL) \

                        (ret = (pcb)->poll((pcb)->callback_arg,(pcb)))

#define TCP_EVENT_ERR(errf,arg,err) \

                        if((errf) != NULL) \

                        (errf)((arg),(err))

#endif /* LWIP_EVENT_API */

/* This structure represents a TCP segment on the unsent and unacked queues */

struct tcp_seg {

  struct tcp_seg *next;    /* used when putting segements on a queue */

  struct pbuf *p;          /* buffer containing data + TCP header */

  void *dataptr;           /* pointer to the TCP data in the pbuf */

  u16_t len;               /* the TCP length of this segment */

  struct tcp_hdr *tcphdr;  /* the TCP header */

};

/* Internal functions and global variables: */

struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);

void tcp_pcb_purge(struct tcp_pcb *pcb);

void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);

u8_t tcp_segs_free(struct tcp_seg *seg);

u8_t tcp_seg_free(struct tcp_seg *seg);

struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);

#define tcp_ack(pcb)     if((pcb)->flags & TF_ACK_DELAY) { \

                            (pcb)->flags &= ~TF_ACK_DELAY; \

                            (pcb)->flags |= TF_ACK_NOW; \

                            tcp_output(pcb); \

                         } else { \

                            (pcb)->flags |= TF_ACK_DELAY; \

                         }

#define tcp_ack_now(pcb) (pcb)->flags |= TF_ACK_NOW; \

                         tcp_output(pcb)

err_t tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags);

err_t tcp_enqueue(struct tcp_pcb *pcb, void *dataptr, u16_t len,

    u8_t flags, u8_t copy,

                u8_t *optdata, u8_t optlen);

void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);

void tcp_rst(u32_t seqno, u32_t ackno,

       struct ip_addr *local_ip, struct ip_addr *remote_ip,

       u16_t local_port, u16_t remote_port);

u32_t tcp_next_iss(void);

void tcp_keepalive(struct tcp_pcb *pcb);

extern struct tcp_pcb *tcp_input_pcb;

extern u32_t tcp_ticks;

#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG

void tcp_debug_print(struct tcp_hdr *tcphdr);

void tcp_debug_print_flags(u8_t flags);

void tcp_debug_print_state(enum tcp_state s);

void tcp_debug_print_pcbs(void);

s16_t tcp_pcbs_sane(void);

#else

#  define tcp_debug_print(tcphdr)

#  define tcp_debug_print_flags(flags)

#  define tcp_debug_print_state(s)

#  define tcp_debug_print_pcbs()

#  define tcp_pcbs_sane() 1

#endif /* TCP_DEBUG */

#if NO_SYS

#define tcp_timer_needed()

#else

void tcp_timer_needed(void);

#endif

/* The TCP PCB lists. */

union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */

        struct tcp_pcb_listen *listen_pcbs;

        struct tcp_pcb *pcbs;

};

extern union tcp_listen_pcbs_t tcp_listen_pcbs;

extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a

              state in which they accept or send

              data. */

extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */

extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */

/* Axioms about the above lists:

   1) Every TCP PCB that is not CLOSED is in one of the lists.

   2) A PCB is only in one of the lists.

   3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.

   4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.

*/

/* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB

   with a PCB list or removes a PCB from a list, respectively. */

#if 0

#define TCP_REG(pcbs, npcb) do {\

                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \

                            for(tcp_tmp_pcb = *pcbs; \

          tcp_tmp_pcb != NULL; \

        tcp_tmp_pcb = tcp_tmp_pcb->next) { \

                                LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \

                            } \

                            LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \

                            npcb->next = *pcbs; \

                            LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \

                            *(pcbs) = npcb; \

                            LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \

              tcp_timer_needed(); \

                            } while(0)

#define TCP_RMV(pcbs, npcb) do { \

                            LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \

                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \

                            if(*pcbs == npcb) { \

                               *pcbs = (*pcbs)->next; \

                            } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \

                               if(tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) { \

                                  tcp_tmp_pcb->next = npcb->next; \

                                  break; \

                               } \

                            } \

                            npcb->next = NULL; \

                            LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \

                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \

                            } while(0)

#else /* LWIP_DEBUG */

#define TCP_REG(pcbs, npcb) do { \

                            npcb->next = *pcbs; \

                            *(pcbs) = npcb; \

              tcp_timer_needed(); \

                            } while(0)

#define TCP_RMV(pcbs, npcb) do { \

                            if(*(pcbs) == npcb) { \

                               (*(pcbs)) = (*pcbs)->next; \

                            } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \

                               if(tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) { \

                                  tcp_tmp_pcb->next = npcb->next; \

                                  break; \

                               } \

                            } \

                            npcb->next = NULL; \

                            } while(0)

#endif /* LWIP_DEBUG */

#endif /* __LWIP_TCP_H__ */