📄 tcp.h
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/*
* Copyright (c) 2001, 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. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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>
*
* $Id: tcp.h,v 1.6 2002/03/04 10:47:56 adam Exp $
*/
#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 "ipv4/lwip/ip.h"
#include "ipv4/lwip/icmp.h"
#include "lwip/sys.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 100 ms). */
/* Application program's interface: */
struct tcp_pcb * tcp_new (void);
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_sndbuf(pcb) ((pcb)->snd_buf)
void tcp_recved (struct tcp_pcb *pcb, u16_t len);
err_t tcp_bind (struct tcp_pcb *pcb, union ip_addr *ipaddr,
u16_t port);
err_t tcp_connect (struct tcp_pcb *pcb, union 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);
/* 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);
#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)
#define TCP_FIN 0x01
#define TCP_SYN 0x02
#define TCP_RST 0x04
#define TCP_PSH 0x08
#define TCP_ACK 0x10
#define TCP_URG 0x20
/* Length of the TCP header, excluding options. */
#define TCP_HLEN 20
#define TCP_TMR_INTERVAL 100 /* The TCP timer interval in
milliseconds. */
#define TCP_FAST_INTERVAL 200 /* the fine grained timeout in
milliseconds */
#define TCP_SLOW_INTERVAL 500 /* the coarse grained timeout in
milliseconds */
#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 */
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 _offset_flags);
PACK_STRUCT_FIELD(u16_t wnd);
PACK_STRUCT_FIELD(u16_t chksum);
PACK_STRUCT_FIELD(u16_t urgp);
} PACK_STRUCT_STRUCT;
#define TCPH_OFFSET(hdr) (NTOHS((hdr)->_offset_flags) >> 8)
#define TCPH_FLAGS(hdr) (NTOHS((hdr)->_offset_flags) & 0xff)
#define TCPH_OFFSET_SET(hdr, offset) (hdr)->_offset_flags = HTONS(((offset) << 8) | TCPH_FLAGS(hdr))
#define TCPH_FLAGS_SET(hdr, flags) (hdr)->_offset_flags = HTONS((TCPH_OFFSET(hdr) << 8) | (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 {
struct tcp_pcb *next; /* for the linked list */
enum tcp_state state; /* TCP state */
void *callback_arg;
/* Function to call when a listener has been connected. */
err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err);
union ip_addr local_ip;
u16_t local_port;
union ip_addr remote_ip;
u16_t remote_port;
/* receiver varables */
u32_t rcv_nxt; /* next seqno expected */
u16_t rcv_wnd; /* receiver window */
/* Timers */
u16_t tmr;
/* Retransmission timer. */
u8_t rtime;
u16_t mss; /* maximum segment size */
u8_t flags;
#define TF_ACK_DELAY 0x01 /* Delayed ACK. */
#define TF_ACK_NOW 0x02 /* Immediate ACK. */
#define TF_INFR 0x04 /* In fast recovery. */
#define TF_RESET 0x08 /* Connection was reset. */
#define TF_CLOSED 0x10 /* Connection was sucessfully closed. */
#define TF_GOT_FIN 0x20 /* Connection was closed by the remote end. */
/* RTT estimation variables. */
u16_t rttest; /* RTT estimate in 500ms ticks */
u32_t rtseq; /* sequence number being timed */
s32_t sa, sv;
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,
snd_lbb;
u16_t snd_buf; /* Avaliable buffer space for sending. */
u8_t snd_queuelen;
/* Function to be called when more send buffer space is avaliable. */
err_t (* sent)(void *arg, struct tcp_pcb *pcb, u16_t space);
u16_t acked;
/* 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);
struct pbuf *recv_data;
/* Function to be called when a connection has been set up. */
err_t (* connected)(void *arg, struct tcp_pcb *pcb, 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);
u8_t polltmr, pollinterval;
/* 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 */
};
struct tcp_pcb_listen {
struct tcp_pcb_listen *next; /* for the linked list */
enum tcp_state state; /* TCP state */
void *callback_arg;
/* Function to call when a listener has been connected. */
void (* accept)(void *arg, struct tcp_pcb *newpcb);
union ip_addr local_ip;
u16_t local_port;
};
/* This structure is used to repressent TCP segments. */
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_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,
union ip_addr *local_ip, union ip_addr *remote_ip,
u16_t local_port, u16_t remote_port);
u32_t tcp_next_iss(void);
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);
int tcp_pcbs_sane(void);
#else
#define tcp_pcbs_sane() 1
#endif /* TCP_DEBUG */
/* The TCP PCB lists. */
extern struct tcp_pcb_listen *tcp_listen_pcbs; /* List of all TCP PCBs in LISTEN state. */
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. */
/* Axoims 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. */
#ifdef LWIP_DEBUG
#define TCP_REG(pcbs, npcb) do {\
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) { \
ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
} \
ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
npcb->next = *pcbs; \
ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
*pcbs = npcb; \
ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
} while(0)
#define TCP_RMV(pcbs, npcb) do { \
ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
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; \
ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
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; \
} 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__ */
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