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* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* This file is part of the lwIP TCP/IP stack.
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* Author: Adam Dunkels <adam@sics.se>
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#ifndef __LWIP_TCP_H__
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#define __LWIP_TCP_H__
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#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
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#include "lwip/pbuf.h"
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#include "lwip/icmp.h"
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#include "lwip/ip6_addr.h"
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/** Function prototype for tcp accept callback functions. Called when a new
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* connection can be accepted on a listening pcb.
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* @param arg Additional argument to pass to the callback function (@see tcp_arg())
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* @param newpcb The new connection pcb
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* @param err An error code if there has been an error accepting.
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* Only return ERR_ABRT if you have called tcp_abort from within the
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typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err);
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/** Function prototype for tcp receive callback functions. Called when data has
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* @param arg Additional argument to pass to the callback function (@see tcp_arg())
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* @param tpcb The connection pcb which received data
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* @param p The received data (or NULL when the connection has been closed!)
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* @param err An error code if there has been an error receiving
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* Only return ERR_ABRT if you have called tcp_abort from within the
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typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb,
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struct pbuf *p, err_t err);
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/** Function prototype for tcp sent callback functions. Called when sent data has
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* been acknowledged by the remote side. Use it to free corresponding resources.
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* This also means that the pcb has now space available to send new data.
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* @param arg Additional argument to pass to the callback function (@see tcp_arg())
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* @param tpcb The connection pcb for which data has been acknowledged
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* @param len The amount of bytes acknowledged
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* @return ERR_OK: try to send some data by calling tcp_output
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* Only return ERR_ABRT if you have called tcp_abort from within the
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typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb,
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/** Function prototype for tcp poll callback functions. Called periodically as
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* specified by @see tcp_poll.
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* @param arg Additional argument to pass to the callback function (@see tcp_arg())
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* @return ERR_OK: try to send some data by calling tcp_output
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* Only return ERR_ABRT if you have called tcp_abort from within the
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typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb);
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/** Function prototype for tcp error callback functions. Called when the pcb
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* receives a RST or is unexpectedly closed for any other reason.
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* @note The corresponding pcb is already freed when this callback is called!
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* @param arg Additional argument to pass to the callback function (@see tcp_arg())
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* @param err Error code to indicate why the pcb has been closed
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* ERR_ABRT: aborted through tcp_abort or by a TCP timer
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* ERR_RST: the connection was reset by the remote host
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typedef void (*tcp_err_fn)(void *arg, err_t err);
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/** Function prototype for tcp connected callback functions. Called when a pcb
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* is connected to the remote side after initiating a connection attempt by
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* calling tcp_connect().
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* @param arg Additional argument to pass to the callback function (@see tcp_arg())
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* @param tpcb The connection pcb which is connected
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* @param err An unused error code, always ERR_OK currently ;-) TODO!
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* Only return ERR_ABRT if you have called tcp_abort from within the
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* @note When a connection attempt fails, the error callback is currently called!
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typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err);
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#if LWIP_CONNECTION_PROXY
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/* see tcp_proxy_listen_input */
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#if LWIP_CALLBACK_API
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/* Function to call when a listener has been connected.
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* @param arg user-supplied argument (tcp_pcb.callback_arg)
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* @param pcb a new tcp_pcb that now is connected
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* @param err an error argument (TODO: that is current always ERR_OK?)
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* @return ERR_OK: accept the new connection,
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* any other err_t abortsthe new connection
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#define DEF_ACCEPT_CALLBACK tcp_accept_fn accept;
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#else /* LWIP_CALLBACK_API */
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#define DEF_ACCEPT_CALLBACK
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#endif /* LWIP_CALLBACK_API */
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* members common to struct tcp_pcb and struct tcp_listen_pcb
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#define TCP_PCB_COMMON(type) \
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type *next; /* for the linked list */ \
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void *callback_arg; \
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/* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
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DEF_ACCEPT_CALLBACK \
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enum tcp_state state; /* TCP state */ \
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/* ports are in host byte order */ \
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/* the TCP protocol control block */
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/** common PCB members */
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/** protocol specific PCB members */
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TCP_PCB_COMMON(struct tcp_pcb);
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/* ports are in host byte order */
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#define TF_ACK_DELAY ((u8_t)0x01U) /* Delayed ACK. */
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#define TF_ACK_NOW ((u8_t)0x02U) /* Immediate ACK. */
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#define TF_INFR ((u8_t)0x04U) /* In fast recovery. */
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#define TF_TIMESTAMP ((u8_t)0x08U) /* Timestamp option enabled */
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#define TF_RXCLOSED ((u8_t)0x10U) /* rx closed by tcp_shutdown */
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#define TF_FIN ((u8_t)0x20U) /* Connection was closed locally (FIN segment enqueued). */
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#define TF_NODELAY ((u8_t)0x40U) /* Disable Nagle algorithm */
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#define TF_NAGLEMEMERR ((u8_t)0x80U) /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
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/* the rest of the fields are in host byte order
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as we have to do some math with them */
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u8_t polltmr, pollinterval;
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/* receiver variables */
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u32_t rcv_nxt; /* next seqno expected */
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u16_t rcv_wnd; /* receiver window available */
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u16_t rcv_ann_wnd; /* receiver window to announce */
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u32_t rcv_ann_right_edge; /* announced right edge of window */
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/* Retransmission timer. */
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u16_t mss; /* maximum segment size */
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/* RTT (round trip time) estimation variables */
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u32_t rttest; /* RTT estimate in 500ms ticks */
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u32_t rtseq; /* sequence number being timed */
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s16_t sa, sv; /* @todo document this */
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s16_t rto; /* retransmission time-out */
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u8_t nrtx; /* number of retransmissions */
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/* fast retransmit/recovery */
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u32_t lastack; /* Highest acknowledged seqno. */
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/* congestion avoidance/control variables */
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/* sender variables */
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u32_t snd_nxt; /* next new seqno to be sent */
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u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
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u32_t snd_lbb; /* Sequence number of next byte to be buffered. */
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u16_t snd_wnd; /* sender window */
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u16_t snd_wnd_max; /* the maximum sender window announced by the remote host */
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u16_t snd_buf; /* Available buffer space for sending (in bytes). */
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#define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3)
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u16_t snd_queuelen; /* Available buffer space for sending (in pbufs). */
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/* Extra bytes available at the end of the last pbuf in unsent. */
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u16_t unsent_oversize;
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#endif /* TCP_OVERSIZE */
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/* These are ordered by sequence number: */
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struct tcp_seg *unsent; /* Unsent (queued) segments. */
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struct tcp_seg *unacked; /* Sent but unacknowledged segments. */
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struct tcp_seg *ooseq; /* Received out of sequence segments. */
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#endif /* TCP_QUEUE_OOSEQ */
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struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
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#if LWIP_CALLBACK_API
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/* Function to be called when more send buffer space is available. */
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/* Function to be called when (in-sequence) data has arrived. */
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/* Function to be called when a connection has been set up. */
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tcp_connected_fn connected;
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/* Function which is called periodically. */
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/* Function to be called whenever a fatal error occurs. */
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#endif /* LWIP_CALLBACK_API */
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#if LWIP_TCP_TIMESTAMPS
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u32_t ts_lastacksent;
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#endif /* LWIP_TCP_TIMESTAMPS */
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/* idle time before KEEPALIVE is sent */
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#if LWIP_TCP_KEEPALIVE
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#endif /* LWIP_TCP_KEEPALIVE */
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/* Persist timer counter */
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/* Persist timer back-off */
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u8_t persist_backoff;
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/* KEEPALIVE counter */
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struct tcp_pcb_listen {
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/* Common members of all PCB types */
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/* Protocol specific PCB members */
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TCP_PCB_COMMON(struct tcp_pcb_listen);
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#if TCP_LISTEN_BACKLOG
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u8_t accepts_pending;
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#endif /* TCP_LISTEN_BACKLOG */
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u8_t accept_any_ip_version;
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#endif /* LWIP_IPV6 */
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LWIP_EVENT_CONNECTED,
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err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
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#endif /* LWIP_EVENT_API */
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/* Application program's interface: */
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struct tcp_pcb * tcp_new (void);
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void tcp_arg (struct tcp_pcb *pcb, void *arg);
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void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept);
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#if LWIP_CONNECTION_PROXY
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/* when proxied connection is accepted there's no listening pcb */
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void tcp_proxy_arg(void *arg);
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void tcp_proxy_accept(tcp_accept_fn accept);
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void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv);
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void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent);
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void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval);
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void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err);
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#define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss)
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#define tcp_sndbuf(pcb) ((pcb)->snd_buf)
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#define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen)
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#define tcp_nagle_disable(pcb) ((pcb)->flags |= TF_NODELAY)
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#define tcp_nagle_enable(pcb) ((pcb)->flags &= ~TF_NODELAY)
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#define tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0)
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#if TCP_LISTEN_BACKLOG
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#define tcp_accepted(pcb) do { \
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LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \
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(((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0)
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#else /* TCP_LISTEN_BACKLOG */
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#define tcp_accepted(pcb) do { \
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LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \
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LWIP_UNUSED_ARG(pcb); } while(0)
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#endif /* TCP_LISTEN_BACKLOG */
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void tcp_recved (struct tcp_pcb *pcb, u16_t len);
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err_t tcp_bind (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
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#if LWIP_CONNECTION_PROXY
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err_t tcp_proxy_bind(struct tcp_pcb *pcb, ip_addr_t *ipaddr,
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#endif /* LWIP_CONNECTION_PROXY */
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err_t tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
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u16_t port, tcp_connected_fn connected);
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struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
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#define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
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#if LWIP_CONNECTION_PROXY
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err_t tcp_proxy_accept_confirm(struct tcp_pcb *npcb);
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void tcp_abort (struct tcp_pcb *pcb);
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err_t tcp_close (struct tcp_pcb *pcb);
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err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx);
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/* Flags for "apiflags" parameter in tcp_write */
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#define TCP_WRITE_FLAG_COPY 0x01
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#define TCP_WRITE_FLAG_MORE 0x02
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err_t tcp_write (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
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void tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
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#define TCP_PRIO_MIN 1
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#define TCP_PRIO_NORMAL 64
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#define TCP_PRIO_MAX 127
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err_t tcp_output (struct tcp_pcb *pcb);
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const char* tcp_debug_state_str(enum tcp_state s);
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struct tcp_pcb * tcp_new_ip6 (void);
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#define tcp_bind_ip6(pcb, ip6addr, port) \
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tcp_bind(pcb, ip6_2_ip(ip6addr), port)
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#define tcp_connect_ip6(pcb, ip6addr, port, connected) \
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tcp_connect(pcb, ip6_2_ip(ip6addr), port, connected)
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struct tcp_pcb * tcp_listen_dual_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
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#define tcp_listen_dual(pcb) tcp_listen_dual_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
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#else /* LWIP_IPV6 */
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#define tcp_listen_dual_with_backlog(pcb, backlog) tcp_listen_with_backlog(pcb, backlog)
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#define tcp_listen_dual(pcb) tcp_listen(pcb)
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#endif /* LWIP_IPV6 */
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#endif /* LWIP_TCP */
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#endif /* __LWIP_TCP_H__ */