include/lwip/tcp.h

0001 /*
0002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
0003  * All rights reserved.
0004  *
0005  * Redistribution and use in source and binary forms, with or without modification,
0006  * are permitted provided that the following conditions are met:
0007  *
0008  * 1. Redistributions of source code must retain the above copyright notice,
0009  *    this list of conditions and the following disclaimer.
0010  * 2. Redistributions in binary form must reproduce the above copyright notice,
0011  *    this list of conditions and the following disclaimer in the documentation
0012  *    and/or other materials provided with the distribution.
0013  * 3. The name of the author may not be used to endorse or promote products
0014  *    derived from this software without specific prior written permission.
0015  *
0016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
0017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
0018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
0019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
0020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
0021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
0024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
0025  * OF SUCH DAMAGE.
0026  *
0027  * This file is part of the lwIP TCP/IP stack.
0028  *
0029  * Author: Adam Dunkels <adam@sics.se>
0030  *
0031  */
0032 #ifndef __LWIP_TCP_H__
0033 #define __LWIP_TCP_H__
0034
0035 #include "lwip/opt.h"
0036
0037 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
0038
0039 #include "lwip/sys.h"
0040 #include "lwip/mem.h"
0041 #include "lwip/pbuf.h"
0042 #include "lwip/ip.h"
0043 #include "lwip/icmp.h"
0044 #include "lwip/err.h"
0045
0046 #ifdef __cplusplus
0047 extern "C" {
0048 #endif
0049
0050 struct tcp_pcb;
0051
0052 /* Functions for interfacing with TCP: */
0053
0054 /* Lower layer interface to TCP: */
0055 #define tcp_init() /* Compatibility define, not init needed. */
0056 void             tcp_tmr     (void);  /* Must be called every
0057                                          TCP_TMR_INTERVAL
0058                                          ms. (Typically 250 ms). */
0059 /* Application program's interface: */
0060 struct tcp_pcb * tcp_new     (void);
0061 struct tcp_pcb * tcp_alloc   (u8_t prio);
0062
0063 void             tcp_arg     (struct tcp_pcb *pcb, void *arg);
0064 void             tcp_accept  (struct tcp_pcb *pcb,
0065                               err_t (* accept)(void *arg, struct tcp_pcb *newpcb,
0066                  err_t err));
0067 void             tcp_recv    (struct tcp_pcb *pcb,
0068                               err_t (* recv)(void *arg, struct tcp_pcb *tpcb,
0069                               struct pbuf *p, err_t err));
0070 void             tcp_sent    (struct tcp_pcb *pcb,
0071                               err_t (* sent)(void *arg, struct tcp_pcb *tpcb,
0072                               u16_t len));
0073 void             tcp_poll    (struct tcp_pcb *pcb,
0074                               err_t (* poll)(void *arg, struct tcp_pcb *tpcb),
0075                               u8_t interval);
0076 void             tcp_err     (struct tcp_pcb *pcb,
0077                               void (* err)(void *arg, err_t err));
0078
0079 #define          tcp_mss(pcb)      ((pcb)->mss)
0080 #define          tcp_sndbuf(pcb)   ((pcb)->snd_buf)
0081 #define          tcp_nagle_disable(pcb)  ((pcb)->flags |= TF_NODELAY)
0082 #define          tcp_nagle_enable(pcb) ((pcb)->flags &= ~TF_NODELAY)
0083 #define          tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0)
0084
0085 #if TCP_LISTEN_BACKLOG
0086 #define          tcp_accepted(pcb) (((struct tcp_pcb_listen *)(pcb))->accepts_pending--)
0087 #else  /* TCP_LISTEN_BACKLOG */
0088 #define          tcp_accepted(pcb)
0089 #endif /* TCP_LISTEN_BACKLOG */
0090
0091 void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);
0092 err_t            tcp_bind    (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
0093                               u16_t port);
0094 err_t            tcp_connect (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
0095                               u16_t port, err_t (* connected)(void *arg,
0096                               struct tcp_pcb *tpcb,
0097                               err_t err));
0098
0099 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
0100 #define          tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
0101
0102 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
0103 #define          tcp_abort(pcb) tcp_abandon((pcb), 1)
0104 err_t            tcp_close   (struct tcp_pcb *pcb);
0105
0106 /* Flags for "apiflags" parameter in tcp_write and tcp_enqueue */
0107 #define TCP_WRITE_FLAG_COPY 0x01
0108 #define TCP_WRITE_FLAG_MORE 0x02
0109
0110 err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
0111                               u8_t apiflags);
0112
0113 void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
0114
0115 #define TCP_PRIO_MIN    1
0116 #define TCP_PRIO_NORMAL 64
0117 #define TCP_PRIO_MAX    127
0118
0119 /* It is also possible to call these two functions at the right
0120    intervals (instead of calling tcp_tmr()). */
0121 void             tcp_slowtmr (void);
0122 void             tcp_fasttmr (void);
0123
0124
0125 /* Only used by IP to pass a TCP segment to TCP: */
0126 void             tcp_input   (struct pbuf *p, struct netif *inp);
0127 /* Used within the TCP code only: */
0128 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
0129 err_t            tcp_output  (struct tcp_pcb *pcb);
0130 void             tcp_rexmit  (struct tcp_pcb *pcb);
0131 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
0132 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
0133 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
0134
0135 /**
0136  * This is the Nagle algorithm: try to combine user data to send as few TCP
0137  * segments as possible. Only send if
0138  * - no previously transmitted data on the connection remains unacknowledged or
0139  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
0140  * - the only unsent segment is at least pcb->mss bytes long (or there is more
0141  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
0142  * - or if we are in fast-retransmit (TF_INFR)
0143  */
0144 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
0145                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
0146                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
0147                               ((tpcb)->unsent->len >= (tpcb)->mss))) \
0148                             ) ? 1 : 0)
0149 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
0150
0151
0152 #define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)
0153 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)
0154 #define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)
0155 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)
0156 /* is b<=a<=c? */
0157 #if 0 /* see bug #10548 */
0158 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
0159 #endif
0160 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
0161 #define TCP_FIN 0x01U
0162 #define TCP_SYN 0x02U
0163 #define TCP_RST 0x04U
0164 #define TCP_PSH 0x08U
0165 #define TCP_ACK 0x10U
0166 #define TCP_URG 0x20U
0167 #define TCP_ECE 0x40U
0168 #define TCP_CWR 0x80U
0169
0170 #define TCP_FLAGS 0x3fU
0171
0172 /* Length of the TCP header, excluding options. */
0173 #define TCP_HLEN 20
0174
0175 #ifndef TCP_TMR_INTERVAL
0176 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
0177 #endif /* TCP_TMR_INTERVAL */
0178
0179 #ifndef TCP_FAST_INTERVAL
0180 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
0181 #endif /* TCP_FAST_INTERVAL */
0182
0183 #ifndef TCP_SLOW_INTERVAL
0184 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
0185 #endif /* TCP_SLOW_INTERVAL */
0186
0187 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
0188 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
0189
0190 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
0191
0192 #ifndef TCP_MSL
0193 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
0194 #endif
0195
0196 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
0197 #ifndef  TCP_KEEPIDLE_DEFAULT
0198 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
0199 #endif
0200
0201 #ifndef  TCP_KEEPINTVL_DEFAULT
0202 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
0203 #endif
0204
0205 #ifndef  TCP_KEEPCNT_DEFAULT
0206 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
0207 #endif
0208
0209 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
0210
0211 /* Fields are (of course) in network byte order.
0212  * Some fields are converted to host byte order in tcp_input().
0213  */
0214 #ifdef PACK_STRUCT_USE_INCLUDES
0215 #  include "arch/bpstruct.h"
0216 #endif
0217 PACK_STRUCT_BEGIN
0218 struct tcp_hdr {
0219   PACK_STRUCT_FIELD(u16_t src);
0220   PACK_STRUCT_FIELD(u16_t dest);
0221   PACK_STRUCT_FIELD(u32_t seqno);
0222   PACK_STRUCT_FIELD(u32_t ackno);
0223   PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
0224   PACK_STRUCT_FIELD(u16_t wnd);
0225   PACK_STRUCT_FIELD(u16_t chksum);
0226   PACK_STRUCT_FIELD(u16_t urgp);
0227 } PACK_STRUCT_STRUCT;
0228 PACK_STRUCT_END
0229 #ifdef PACK_STRUCT_USE_INCLUDES
0230 #  include "arch/epstruct.h"
0231 #endif
0232
0233 #define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
0234 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
0235 #define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
0236
0237 #define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
0238 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
0239 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & htons((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
0240 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
0241 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
0242
0243 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
0244
0245 enum tcp_state {
0246   CLOSED      = 0,
0247   LISTEN      = 1,
0248   SYN_SENT    = 2,
0249   SYN_RCVD    = 3,
0250   ESTABLISHED = 4,
0251   FIN_WAIT_1  = 5,
0252   FIN_WAIT_2  = 6,
0253   CLOSE_WAIT  = 7,
0254   CLOSING     = 8,
0255   LAST_ACK    = 9,
0256   TIME_WAIT   = 10
0257 };
0258
0259 /** Flags used on input processing, not on pcb->flags
0260 */
0261 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
0262 #define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */
0263 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
0264
0265
0266 #if LWIP_CALLBACK_API
0267   /* Function to call when a listener has been connected.
0268    * @param arg user-supplied argument (tcp_pcb.callback_arg)
0269    * @param pcb a new tcp_pcb that now is connected
0270    * @param err an error argument (TODO: that is current always ERR_OK?)
0271    * @return ERR_OK: accept the new connection,
0272    *                 any other err_t abortsthe new connection
0273    */
0274 #define DEF_ACCEPT_CALLBACK  err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err)
0275 #else /* LWIP_CALLBACK_API */
0276 #define DEF_ACCEPT_CALLBACK
0277 #endif /* LWIP_CALLBACK_API */
0278
0279 /**
0280  * members common to struct tcp_pcb and struct tcp_listen_pcb
0281  */
0282 #define TCP_PCB_COMMON(type) \
0283   type *next; /* for the linked list */ \
0284   enum tcp_state state; /* TCP state */ \
0285   u8_t prio; \
0286   void *callback_arg; \
0287   /* ports are in host byte order */ \
0288   u16_t local_port; \
0289   /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
0290   DEF_ACCEPT_CALLBACK
0291
0292
0293 /* the TCP protocol control block */
0294 struct tcp_pcb {
0295 /** common PCB members */
0296   IP_PCB;
0297 /** protocol specific PCB members */
0298   TCP_PCB_COMMON(struct tcp_pcb);
0299
0300   /* ports are in host byte order */
0301   u16_t remote_port;
0302
0303   u8_t flags;
0304 #define TF_ACK_DELAY   ((u8_t)0x01U)   /* Delayed ACK. */
0305 #define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
0306 #define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
0307 #define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
0308 #define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
0309 #define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
0310 #define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
0311
0312   /* the rest of the fields are in host byte order
0313      as we have to do some math with them */
0314   /* receiver variables */
0315   u32_t rcv_nxt;   /* next seqno expected */
0316   u16_t rcv_wnd;   /* receiver window available */
0317   u16_t rcv_ann_wnd; /* receiver window to announce */
0318   u32_t rcv_ann_right_edge; /* announced right edge of window */
0319
0320   /* Timers */
0321   u32_t tmr;
0322   u8_t polltmr, pollinterval;
0323
0324   /* Retransmission timer. */
0325   s16_t rtime;
0326
0327   u16_t mss;   /* maximum segment size */
0328
0329   /* RTT (round trip time) estimation variables */
0330   u32_t rttest; /* RTT estimate in 500ms ticks */
0331   u32_t rtseq;  /* sequence number being timed */
0332   s16_t sa, sv; /* @todo document this */
0333
0334   s16_t rto;    /* retransmission time-out */
0335   u8_t nrtx;    /* number of retransmissions */
0336
0337   /* fast retransmit/recovery */
0338   u32_t lastack; /* Highest acknowledged seqno. */
0339   u8_t dupacks;
0340
0341   /* congestion avoidance/control variables */
0342   u16_t cwnd;
0343   u16_t ssthresh;
0344
0345   /* sender variables */
0346   u32_t snd_nxt;   /* next new seqno to be sent */
0347   u16_t snd_wnd;   /* sender window */
0348   u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
0349                              window update. */
0350   u32_t snd_lbb;       /* Sequence number of next byte to be buffered. */
0351
0352   u16_t acked;
0353
0354   u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
0355 #define TCP_SNDQUEUELEN_OVERFLOW (0xffff-3)
0356   u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
0357
0358
0359   /* These are ordered by sequence number: */
0360   struct tcp_seg *unsent;   /* Unsent (queued) segments. */
0361   struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */
0362 #if TCP_QUEUE_OOSEQ
0363   struct tcp_seg *ooseq;    /* Received out of sequence segments. */
0364 #endif /* TCP_QUEUE_OOSEQ */
0365
0366   struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
0367
0368 #if LWIP_CALLBACK_API
0369   /* Function to be called when more send buffer space is available.
0370    * @param arg user-supplied argument (tcp_pcb.callback_arg)
0371    * @param pcb the tcp_pcb which has send buffer space available
0372    * @param space the amount of bytes available
0373    * @return ERR_OK: try to send some data by calling tcp_output
0374    */
0375   err_t (* sent)(void *arg, struct tcp_pcb *pcb, u16_t space);
0376
0377   /* Function to be called when (in-sequence) data has arrived.
0378    * @param arg user-supplied argument (tcp_pcb.callback_arg)
0379    * @param pcb the tcp_pcb for which data has arrived
0380    * @param p the packet buffer which arrived
0381    * @param err an error argument (TODO: that is current always ERR_OK?)
0382    * @return ERR_OK: try to send some data by calling tcp_output
0383    */
0384   err_t (* recv)(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
0385
0386   /* Function to be called when a connection has been set up.
0387    * @param arg user-supplied argument (tcp_pcb.callback_arg)
0388    * @param pcb the tcp_pcb that now is connected
0389    * @param err an error argument (TODO: that is current always ERR_OK?)
0390    * @return value is currently ignored
0391    */
0392   err_t (* connected)(void *arg, struct tcp_pcb *pcb, err_t err);
0393
0394   /* Function which is called periodically.
0395    * The period can be adjusted in multiples of the TCP slow timer interval
0396    * by changing tcp_pcb.polltmr.
0397    * @param arg user-supplied argument (tcp_pcb.callback_arg)
0398    * @param pcb the tcp_pcb to poll for
0399    * @return ERR_OK: try to send some data by calling tcp_output
0400    */
0401   err_t (* poll)(void *arg, struct tcp_pcb *pcb);
0402
0403   /* Function to be called whenever a fatal error occurs.
0404    * There is no pcb parameter since most of the times, the pcb is
0405    * already deallocated (or there is no pcb) when this function is called.
0406    * @param arg user-supplied argument (tcp_pcb.callback_arg)
0407    * @param err an indication why the error callback is called:
0408    *            ERR_ABRT: aborted through tcp_abort or by a TCP timer
0409    *            ERR_RST: the connection was reset by the remote host
0410    */
0411   void (* errf)(void *arg, err_t err);
0412 #endif /* LWIP_CALLBACK_API */
0413
0414 #if LWIP_TCP_TIMESTAMPS
0415   u32_t ts_lastacksent;
0416   u32_t ts_recent;
0417 #endif /* LWIP_TCP_TIMESTAMPS */
0418
0419   /* idle time before KEEPALIVE is sent */
0420   u32_t keep_idle;
0421 #if LWIP_TCP_KEEPALIVE
0422   u32_t keep_intvl;
0423   u32_t keep_cnt;
0424 #endif /* LWIP_TCP_KEEPALIVE */
0425
0426   /* Persist timer counter */
0427   u32_t persist_cnt;
0428   /* Persist timer back-off */
0429   u8_t persist_backoff;
0430
0431   /* KEEPALIVE counter */
0432   u8_t keep_cnt_sent;
0433 };
0434
0435 struct tcp_pcb_listen {
0436 /* Common members of all PCB types */
0437   IP_PCB;
0438 /* Protocol specific PCB members */
0439   TCP_PCB_COMMON(struct tcp_pcb_listen);
0440
0441 #if TCP_LISTEN_BACKLOG
0442   u8_t backlog;
0443   u8_t accepts_pending;
0444 #endif /* TCP_LISTEN_BACKLOG */
0445 };
0446
0447 #if LWIP_EVENT_API
0448
0449 enum lwip_event {
0450   LWIP_EVENT_ACCEPT,
0451   LWIP_EVENT_SENT,
0452   LWIP_EVENT_RECV,
0453   LWIP_EVENT_CONNECTED,
0454   LWIP_EVENT_POLL,
0455   LWIP_EVENT_ERR
0456 };
0457
0458 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
0459          enum lwip_event,
0460          struct pbuf *p,
0461          u16_t size,
0462          err_t err);
0463
0464 #define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
0465                 LWIP_EVENT_ACCEPT, NULL, 0, err)
0466 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
0467                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
0468 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
0469                 LWIP_EVENT_RECV, (p), 0, (err))
0470 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
0471                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
0472 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
0473                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
0474 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
0475                 LWIP_EVENT_ERR, NULL, 0, (err))
0476 #else /* LWIP_EVENT_API */
0477
0478 #define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
0479   do {                                                         \
0480     if((pcb)->accept != NULL)                                  \
0481       (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
0482     else (ret) = ERR_OK;                                       \
0483   } while (0)
0484
0485 #define TCP_EVENT_SENT(pcb,space,ret)                          \
0486   do {                                                         \
0487     if((pcb)->sent != NULL)                                    \
0488       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
0489     else (ret) = ERR_OK;                                       \
0490   } while (0)
0491
0492 #define TCP_EVENT_RECV(pcb,p,err,ret)                           \
0493   do {                                                          \
0494     if((pcb)->recv != NULL) {                                   \
0495       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err)); \
0496     } else {                                                    \
0497       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));           \
0498     }                                                           \
0499   } while (0)
0500
0501 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
0502   do {                                                           \
0503     if((pcb)->connected != NULL)                                 \
0504       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
0505     else (ret) = ERR_OK;                                         \
0506   } while (0)
0507
0508 #define TCP_EVENT_POLL(pcb,ret)                                \
0509   do {                                                         \
0510     if((pcb)->poll != NULL)                                    \
0511       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
0512     else (ret) = ERR_OK;                                       \
0513   } while (0)
0514
0515 #define TCP_EVENT_ERR(errf,arg,err)                            \
0516   do {                                                         \
0517     if((errf) != NULL)                                         \
0518       (errf)((arg),(err));                                     \
0519   } while (0)
0520
0521 #endif /* LWIP_EVENT_API */
0522
0523 /* This structure represents a TCP segment on the unsent and unacked queues */
0524 struct tcp_seg {
0525   struct tcp_seg *next;    /* used when putting segements on a queue */
0526   struct pbuf *p;          /* buffer containing data + TCP header */
0527   void *dataptr;           /* pointer to the TCP data in the pbuf */
0528   u16_t len;               /* the TCP length of this segment */
0529   u8_t  flags;
0530 #define TF_SEG_OPTS_MSS   (u8_t)0x01U   /* Include MSS option. */
0531 #define TF_SEG_OPTS_TS    (u8_t)0x02U   /* Include timestamp option. */
0532   struct tcp_hdr *tcphdr;  /* the TCP header */
0533 };
0534
0535 #define LWIP_TCP_OPT_LENGTH(flags)              \
0536   (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
0537   (flags & TF_SEG_OPTS_TS  ? 12 : 0)
0538
0539 /** This returns a TCP header option for MSS in an u32_t */
0540 #define TCP_BUILD_MSS_OPTION(x) (x) = htonl(((u32_t)2 << 24) |          \
0541                                             ((u32_t)4 << 16) |          \
0542                                             (((u32_t)TCP_MSS / 256) << 8) | \
0543                                             (TCP_MSS & 255))
0544
0545 /* Internal functions and global variables: */
0546 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
0547 void tcp_pcb_purge(struct tcp_pcb *pcb);
0548 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
0549
0550 u8_t tcp_segs_free(struct tcp_seg *seg);
0551 u8_t tcp_seg_free(struct tcp_seg *seg);
0552 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
0553
0554 #define tcp_ack(pcb)                               \
0555   do {                                             \
0556     if((pcb)->flags & TF_ACK_DELAY) {              \
0557       (pcb)->flags &= ~TF_ACK_DELAY;               \
0558       (pcb)->flags |= TF_ACK_NOW;                  \
0559       tcp_output(pcb);                             \
0560     }                                              \
0561     else {                                         \
0562       (pcb)->flags |= TF_ACK_DELAY;                \
0563     }                                              \
0564   } while (0)
0565
0566 #define tcp_ack_now(pcb)                           \
0567   do {                                             \
0568     (pcb)->flags |= TF_ACK_NOW;                    \
0569     tcp_output(pcb);                               \
0570   } while (0)
0571
0572 err_t tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags);
0573 err_t tcp_enqueue(struct tcp_pcb *pcb, void *dataptr, u16_t len,
0574                   u8_t flags, u8_t apiflags, u8_t optflags);
0575
0576 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
0577
0578 void tcp_rst(u32_t seqno, u32_t ackno,
0579        struct ip_addr *local_ip, struct ip_addr *remote_ip,
0580        u16_t local_port, u16_t remote_port);
0581
0582 u32_t tcp_next_iss(void);
0583
0584 void tcp_keepalive(struct tcp_pcb *pcb);
0585 void tcp_zero_window_probe(struct tcp_pcb *pcb);
0586
0587 #if TCP_CALCULATE_EFF_SEND_MSS
0588 u16_t tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr);
0589 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
0590
0591 #if LWIP_CALLBACK_API
0592 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
0593 #endif /* LWIP_CALLBACK_API */
0594
0595 extern struct tcp_pcb *tcp_input_pcb;
0596 extern u32_t tcp_ticks;
0597
0598 const char* tcp_debug_state_str(enum tcp_state s);
0599 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
0600 void tcp_debug_print(struct tcp_hdr *tcphdr);
0601 void tcp_debug_print_flags(u8_t flags);
0602 void tcp_debug_print_state(enum tcp_state s);
0603 void tcp_debug_print_pcbs(void);
0604 s16_t tcp_pcbs_sane(void);
0605 #else
0606 #  define tcp_debug_print(tcphdr)
0607 #  define tcp_debug_print_flags(flags)
0608 #  define tcp_debug_print_state(s)
0609 #  define tcp_debug_print_pcbs()
0610 #  define tcp_pcbs_sane() 1
0611 #endif /* TCP_DEBUG */
0612
0613 #if NO_SYS
0614 #define tcp_timer_needed()
0615 #else
0616 void tcp_timer_needed(void);
0617 #endif
0618
0619 /* The TCP PCB lists. */
0620 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
0621   struct tcp_pcb_listen *listen_pcbs;
0622   struct tcp_pcb *pcbs;
0623 };
0624 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
0625 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
0626               state in which they accept or send
0627               data. */
0628 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
0629
0630 extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */
0631
0632 /* Axioms about the above lists:
0633    1) Every TCP PCB that is not CLOSED is in one of the lists.
0634    2) A PCB is only in one of the lists.
0635    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
0636    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
0637 */
0638
0639 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
0640    with a PCB list or removes a PCB from a list, respectively. */
0641 #if 0
0642 #define TCP_REG(pcbs, npcb) do {\
0643                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \
0644                             for(tcp_tmp_pcb = *pcbs; \
0645           tcp_tmp_pcb != NULL; \
0646         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
0647                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
0648                             } \
0649                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
0650                             npcb->next = *pcbs; \
0651                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
0652                             *(pcbs) = npcb; \
0653                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
0654               tcp_timer_needed(); \
0655                             } while(0)
0656 #define TCP_RMV(pcbs, npcb) do { \
0657                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
0658                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \
0659                             if(*pcbs == npcb) { \
0660                                *pcbs = (*pcbs)->next; \
0661                             } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
0662                                if(tcp_tmp_pcb->next == npcb) { \
0663                                   tcp_tmp_pcb->next = npcb->next; \
0664                                   break; \
0665                                } \
0666                             } \
0667                             npcb->next = NULL; \
0668                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
0669                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \
0670                             } while(0)
0671
0672 #else /* LWIP_DEBUG */
0673
0674 #define TCP_REG(pcbs, npcb)                        \
0675   do {                                             \
0676     npcb->next = *pcbs;                            \
0677     *(pcbs) = npcb;                                \
0678     tcp_timer_needed();                            \
0679   } while (0)
0680
0681 #define TCP_RMV(pcbs, npcb)                        \
0682   do {                                             \
0683     if(*(pcbs) == npcb) {                          \
0684       (*(pcbs)) = (*pcbs)->next;                   \
0685     }                                              \
0686     else {                                         \
0687       for(tcp_tmp_pcb = *pcbs;                                         \
0688           tcp_tmp_pcb != NULL;                                         \
0689           tcp_tmp_pcb = tcp_tmp_pcb->next) {                           \
0690         if(tcp_tmp_pcb->next == npcb) {   \
0691           tcp_tmp_pcb->next = npcb->next;          \
0692           break;                                   \
0693         }                                          \
0694       }                                            \
0695     }                                              \
0696     npcb->next = NULL;                             \
0697   } while(0)
0698
0699 #endif /* LWIP_DEBUG */
0700
0701 #ifdef __cplusplus
0702 }
0703 #endif
0704
0705 #endif /* LWIP_TCP */
0706
0707 #endif /* __LWIP_TCP_H__ */