/* * 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"#endifPACK_STRUCT_BEGINstruct 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;