tcp.h

00001 /*
00002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00003  * All rights reserved. 
00004  * 
00005  * Redistribution and use in source and binary forms, with or without modification, 
00006  * are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright notice,
00009  *    this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright notice,
00011  *    this list of conditions and the following disclaimer in the documentation
00012  *    and/or other materials provided with the distribution.
00013  * 3. The name of the author may not be used to endorse or promote products
00014  *    derived from this software without specific prior written permission. 
00015  *
00016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00025  * OF SUCH DAMAGE.
00026  *
00027  * This file is part of the lwIP TCP/IP stack.
00028  * 
00029  * Author: Adam Dunkels <adam@sics.se>
00030  *
00031  */
00032 #ifndef __LWIP_TCP_H__
00033 #define __LWIP_TCP_H__
00034 
00035 #include "lwip/opt.h"
00036 
00037 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
00038 
00039 #include "lwip/sys.h"
00040 #include "lwip/mem.h"
00041 #include "lwip/pbuf.h"
00042 #include "lwip/ip.h"
00043 #include "lwip/icmp.h"
00044 #include "lwip/err.h"
00045 
00046 #ifdef __cplusplus
00047 extern "C" {
00048 #endif
00049 
00050 struct tcp_pcb;
00051 
00052 /* Functions for interfacing with TCP: */
00053 
00054 /* Lower layer interface to TCP: */
00055 #define tcp_init() /* Compatibility define, not init needed. */
00056 void             tcp_tmr     (void);  /* Must be called every
00057                                          TCP_TMR_INTERVAL
00058                                          ms. (Typically 250 ms). */
00059 /* Application program's interface: */
00060 struct tcp_pcb * tcp_new     (void);
00061 struct tcp_pcb * tcp_alloc   (u8_t prio);
00062 
00063 void             tcp_arg     (struct tcp_pcb *pcb, void *arg);
00064 void             tcp_accept  (struct tcp_pcb *pcb,
00065                               err_t (* accept)(void *arg, struct tcp_pcb *newpcb,
00066                  err_t err));
00067 void             tcp_recv    (struct tcp_pcb *pcb,
00068                               err_t (* recv)(void *arg, struct tcp_pcb *tpcb,
00069                               struct pbuf *p, err_t err));
00070 void             tcp_sent    (struct tcp_pcb *pcb,
00071                               err_t (* sent)(void *arg, struct tcp_pcb *tpcb,
00072                               u16_t len));
00073 void             tcp_poll    (struct tcp_pcb *pcb,
00074                               err_t (* poll)(void *arg, struct tcp_pcb *tpcb),
00075                               u8_t interval);
00076 void             tcp_err     (struct tcp_pcb *pcb,
00077                               void (* err)(void *arg, err_t err));
00078 
00079 #define          tcp_mss(pcb)      ((pcb)->mss)
00080 #define          tcp_sndbuf(pcb)   ((pcb)->snd_buf)
00081 
00082 #if TCP_LISTEN_BACKLOG
00083 #define          tcp_accepted(pcb) (((struct tcp_pcb_listen *)(pcb))->accepts_pending--)
00084 #else  /* TCP_LISTEN_BACKLOG */
00085 #define          tcp_accepted(pcb)
00086 #endif /* TCP_LISTEN_BACKLOG */
00087 
00088 void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);
00089 err_t            tcp_bind    (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
00090                               u16_t port);
00091 err_t            tcp_connect (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
00092                               u16_t port, err_t (* connected)(void *arg,
00093                               struct tcp_pcb *tpcb,
00094                               err_t err));
00095 
00096 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
00097 #define          tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
00098 
00099 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
00100 #define          tcp_abort(pcb) tcp_abandon((pcb), 1)
00101 err_t            tcp_close   (struct tcp_pcb *pcb);
00102 
00103 /* Flags for "apiflags" parameter in tcp_write and tcp_enqueue */
00104 #define TCP_WRITE_FLAG_COPY 0x01
00105 #define TCP_WRITE_FLAG_MORE 0x02
00106 
00107 err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
00108                               u8_t apiflags);
00109 
00110 void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
00111 
00112 #define TCP_PRIO_MIN    1
00113 #define TCP_PRIO_NORMAL 64
00114 #define TCP_PRIO_MAX    127
00115 
00116 /* It is also possible to call these two functions at the right
00117    intervals (instead of calling tcp_tmr()). */
00118 void             tcp_slowtmr (void);
00119 void             tcp_fasttmr (void);
00120 
00121 
00122 /* Only used by IP to pass a TCP segment to TCP: */
00123 void             tcp_input   (struct pbuf *p, struct netif *inp);
00124 /* Used within the TCP code only: */
00125 err_t            tcp_output  (struct tcp_pcb *pcb);
00126 void             tcp_rexmit  (struct tcp_pcb *pcb);
00127 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
00128 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
00129 
00130 /**
00131  * This is the Nagle algorithm: inhibit the sending of new TCP
00132  * segments when new outgoing data arrives from the user if any
00133  * previously transmitted data on the connection remains
00134  * unacknowledged.
00135  */
00136 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
00137                             ((tpcb)->flags & TF_NODELAY) || \
00138                             (((tpcb)->unsent != NULL) && ((tpcb)->unsent->next != NULL))) ? \
00139                                 1 : 0)
00140 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
00141 
00142 
00143 #define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)
00144 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)
00145 #define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)
00146 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)
00147 /* is b<=a<=c? */
00148 #if 0 /* see bug #10548 */
00149 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
00150 #endif
00151 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
00152 #define TCP_FIN 0x01U
00153 #define TCP_SYN 0x02U
00154 #define TCP_RST 0x04U
00155 #define TCP_PSH 0x08U
00156 #define TCP_ACK 0x10U
00157 #define TCP_URG 0x20U
00158 #define TCP_ECE 0x40U
00159 #define TCP_CWR 0x80U
00160 
00161 #define TCP_FLAGS 0x3fU
00162 
00163 /* Length of the TCP header, excluding options. */
00164 #define TCP_HLEN 20
00165 
00166 #ifndef TCP_TMR_INTERVAL
00167 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
00168 #endif /* TCP_TMR_INTERVAL */
00169 
00170 #ifndef TCP_FAST_INTERVAL
00171 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
00172 #endif /* TCP_FAST_INTERVAL */
00173 
00174 #ifndef TCP_SLOW_INTERVAL
00175 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
00176 #endif /* TCP_SLOW_INTERVAL */
00177 
00178 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
00179 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
00180 
00181 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
00182 
00183 #ifndef TCP_MSL
00184 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
00185 #endif
00186 
00187 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
00188 #ifndef  TCP_KEEPIDLE_DEFAULT
00189 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
00190 #endif
00191 
00192 #ifndef  TCP_KEEPINTVL_DEFAULT
00193 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
00194 #endif
00195 
00196 #ifndef  TCP_KEEPCNT_DEFAULT
00197 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
00198 #endif
00199 
00200 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
00201 
00202 /* Fields are (of course) in network byte order.
00203  * Some fields are converted to host byte order in tcp_input().
00204  */
00205 #ifdef PACK_STRUCT_USE_INCLUDES
00206 #  include "arch/bpstruct.h"
00207 #endif
00208 PACK_STRUCT_BEGIN
00209 struct tcp_hdr {
00210   PACK_STRUCT_FIELD(u16_t src);
00211   PACK_STRUCT_FIELD(u16_t dest);
00212   PACK_STRUCT_FIELD(u32_t seqno);
00213   PACK_STRUCT_FIELD(u32_t ackno);
00214   PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
00215   PACK_STRUCT_FIELD(u16_t wnd);
00216   PACK_STRUCT_FIELD(u16_t chksum);
00217   PACK_STRUCT_FIELD(u16_t urgp);
00218 } PACK_STRUCT_STRUCT;
00219 PACK_STRUCT_END
00220 #ifdef PACK_STRUCT_USE_INCLUDES
00221 #  include "arch/epstruct.h"
00222 #endif
00223 
00224 #define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
00225 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
00226 #define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
00227 
00228 #define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
00229 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
00230 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons((ntohs((phdr)->_hdrlen_rsvd_flags) & ~TCP_FLAGS) | (flags))
00231 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (flags))
00232 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
00233 
00234 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & TCP_FIN || \
00235           TCPH_FLAGS((seg)->tcphdr) & TCP_SYN)? 1: 0))
00236 
00237 enum tcp_state {
00238   CLOSED      = 0,
00239   LISTEN      = 1,
00240   SYN_SENT    = 2,
00241   SYN_RCVD    = 3,
00242   ESTABLISHED = 4,
00243   FIN_WAIT_1  = 5,
00244   FIN_WAIT_2  = 6,
00245   CLOSE_WAIT  = 7,
00246   CLOSING     = 8,
00247   LAST_ACK    = 9,
00248   TIME_WAIT   = 10
00249 };
00250 
00251 /** Flags used on input processing, not on pcb->flags
00252 */
00253 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
00254 #define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */
00255 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
00256 
00257 
00258 #if LWIP_CALLBACK_API
00259   /* Function to call when a listener has been connected.
00260    * @param arg user-supplied argument (tcp_pcb.callback_arg)
00261    * @param pcb a new tcp_pcb that now is connected
00262    * @param err an error argument (TODO: that is current always ERR_OK?)
00263    * @return ERR_OK: accept the new connection,
00264    *                 any other err_t abortsthe new connection
00265    */
00266 #define DEF_ACCEPT_CALLBACK  err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err)
00267 #else /* LWIP_CALLBACK_API */
00268 #define DEF_ACCEPT_CALLBACK
00269 #endif /* LWIP_CALLBACK_API */
00270 
00271 /**
00272  * members common to struct tcp_pcb and struct tcp_listen_pcb
00273  */
00274 #define TCP_PCB_COMMON(type) \
00275   type *next; /* for the linked list */ \
00276   enum tcp_state state; /* TCP state */ \
00277   u8_t prio; \
00278   void *callback_arg; \
00279   /* ports are in host byte order */ \
00280   u16_t local_port; \
00281   /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
00282   DEF_ACCEPT_CALLBACK
00283 
00284 
00285 /* the TCP protocol control block */
00286 struct tcp_pcb {
00287 /** common PCB members */
00288   IP_PCB;
00289 /** protocol specific PCB members */
00290   TCP_PCB_COMMON(struct tcp_pcb);
00291 
00292   /* ports are in host byte order */
00293   u16_t remote_port;
00294   
00295   u8_t flags;
00296 #define TF_ACK_DELAY   ((u8_t)0x01U)   /* Delayed ACK. */
00297 #define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
00298 #define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
00299 #define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
00300 #define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
00301 #define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
00302 #define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
00303 
00304   /* the rest of the fields are in host byte order
00305      as we have to do some math with them */
00306   /* receiver variables */
00307   u32_t rcv_nxt;   /* next seqno expected */
00308   u16_t rcv_wnd;   /* receiver window available */
00309   u16_t rcv_ann_wnd; /* receiver window to announce */
00310   u32_t rcv_ann_right_edge; /* announced right edge of window */
00311 
00312   /* Timers */
00313   u32_t tmr;
00314   u8_t polltmr, pollinterval;
00315   
00316   /* Retransmission timer. */
00317   s16_t rtime;
00318   
00319   u16_t mss;   /* maximum segment size */
00320   
00321   /* RTT (round trip time) estimation variables */
00322   u32_t rttest; /* RTT estimate in 500ms ticks */
00323   u32_t rtseq;  /* sequence number being timed */
00324   s16_t sa, sv; /* @todo document this */
00325 
00326   s16_t rto;    /* retransmission time-out */
00327   u8_t nrtx;    /* number of retransmissions */
00328 
00329   /* fast retransmit/recovery */
00330   u32_t lastack; /* Highest acknowledged seqno. */
00331   u8_t dupacks;
00332   
00333   /* congestion avoidance/control variables */
00334   u16_t cwnd;  
00335   u16_t ssthresh;
00336 
00337   /* sender variables */
00338   u32_t snd_nxt,   /* next seqno to be sent */
00339     snd_max;       /* Highest seqno sent. */
00340   u16_t snd_wnd;   /* sender window */
00341   u32_t snd_wl1, snd_wl2, /* Sequence and acknowledgement numbers of last
00342                              window update. */
00343     snd_lbb;       /* Sequence number of next byte to be buffered. */
00344 
00345   u16_t acked;
00346   
00347   u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
00348 #define TCP_SNDQUEUELEN_OVERFLOW (0xffff-3)
00349   u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
00350   
00351   
00352   /* These are ordered by sequence number: */
00353   struct tcp_seg *unsent;   /* Unsent (queued) segments. */
00354   struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */
00355 #if TCP_QUEUE_OOSEQ  
00356   struct tcp_seg *ooseq;    /* Received out of sequence segments. */
00357 #endif /* TCP_QUEUE_OOSEQ */
00358 
00359   struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
00360 
00361 #if LWIP_CALLBACK_API
00362   /* Function to be called when more send buffer space is available.
00363    * @param arg user-supplied argument (tcp_pcb.callback_arg)
00364    * @param pcb the tcp_pcb which has send buffer space available
00365    * @param space the amount of bytes available
00366    * @return ERR_OK: try to send some data by calling tcp_output
00367    */
00368   err_t (* sent)(void *arg, struct tcp_pcb *pcb, u16_t space);
00369   
00370   /* Function to be called when (in-sequence) data has arrived.
00371    * @param arg user-supplied argument (tcp_pcb.callback_arg)
00372    * @param pcb the tcp_pcb for which data has arrived
00373    * @param p the packet buffer which arrived
00374    * @param err an error argument (TODO: that is current always ERR_OK?)
00375    * @return ERR_OK: try to send some data by calling tcp_output
00376    */
00377   err_t (* recv)(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
00378 
00379   /* Function to be called when a connection has been set up.
00380    * @param arg user-supplied argument (tcp_pcb.callback_arg)
00381    * @param pcb the tcp_pcb that now is connected
00382    * @param err an error argument (TODO: that is current always ERR_OK?)
00383    * @return value is currently ignored
00384    */
00385   err_t (* connected)(void *arg, struct tcp_pcb *pcb, err_t err);
00386 
00387   /* Function which is called periodically.
00388    * The period can be adjusted in multiples of the TCP slow timer interval
00389    * by changing tcp_pcb.polltmr.
00390    * @param arg user-supplied argument (tcp_pcb.callback_arg)
00391    * @param pcb the tcp_pcb to poll for
00392    * @return ERR_OK: try to send some data by calling tcp_output
00393    */
00394   err_t (* poll)(void *arg, struct tcp_pcb *pcb);
00395 
00396   /* Function to be called whenever a fatal error occurs.
00397    * There is no pcb parameter since most of the times, the pcb is
00398    * already deallocated (or there is no pcb) when this function is called.
00399    * @param arg user-supplied argument (tcp_pcb.callback_arg)
00400    * @param err an indication why the error callback is called:
00401    *            ERR_ABRT: aborted through tcp_abort or by a TCP timer
00402    *            ERR_RST: the connection was reset by the remote host
00403    */
00404   void (* errf)(void *arg, err_t err);
00405 #endif /* LWIP_CALLBACK_API */
00406 
00407 #if LWIP_TCP_TIMESTAMPS
00408   u32_t ts_lastacksent;
00409   u32_t ts_recent;
00410 #endif /* LWIP_TCP_TIMESTAMPS */
00411 
00412   /* idle time before KEEPALIVE is sent */
00413   u32_t keep_idle;
00414 #if LWIP_TCP_KEEPALIVE
00415   u32_t keep_intvl;
00416   u32_t keep_cnt;
00417 #endif /* LWIP_TCP_KEEPALIVE */
00418   
00419   /* Persist timer counter */
00420   u32_t persist_cnt;
00421   /* Persist timer back-off */
00422   u8_t persist_backoff;
00423 
00424   /* KEEPALIVE counter */
00425   u8_t keep_cnt_sent;
00426 };
00427 
00428 struct tcp_pcb_listen {  
00429 /* Common members of all PCB types */
00430   IP_PCB;
00431 /* Protocol specific PCB members */
00432   TCP_PCB_COMMON(struct tcp_pcb_listen);
00433 
00434 #if TCP_LISTEN_BACKLOG
00435   u8_t backlog;
00436   u8_t accepts_pending;
00437 #endif /* TCP_LISTEN_BACKLOG */
00438 };
00439 
00440 #if LWIP_EVENT_API
00441 
00442 enum lwip_event {
00443   LWIP_EVENT_ACCEPT,
00444   LWIP_EVENT_SENT,
00445   LWIP_EVENT_RECV,
00446   LWIP_EVENT_CONNECTED,
00447   LWIP_EVENT_POLL,
00448   LWIP_EVENT_ERR
00449 };
00450 
00451 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
00452          enum lwip_event,
00453          struct pbuf *p,
00454          u16_t size,
00455          err_t err);
00456 
00457 #define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00458                 LWIP_EVENT_ACCEPT, NULL, 0, err)
00459 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00460                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
00461 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00462                 LWIP_EVENT_RECV, (p), 0, (err))
00463 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00464                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
00465 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00466                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
00467 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
00468                 LWIP_EVENT_ERR, NULL, 0, (err))
00469 #else /* LWIP_EVENT_API */
00470 
00471 #define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
00472   do {                                                         \
00473     if((pcb)->accept != NULL)                                  \
00474       (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
00475   } while (0)
00476 
00477 #define TCP_EVENT_SENT(pcb,space,ret)                          \
00478   do {                                                         \
00479     if((pcb)->sent != NULL)                                    \
00480       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
00481   } while (0)
00482 
00483 #define TCP_EVENT_RECV(pcb,p,err,ret)                           \
00484   do {                                                          \
00485     if((pcb)->recv != NULL) {                                   \
00486       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err)); \
00487     } else {                                                    \
00488       (ret) = ERR_OK;                                           \
00489       if (p != NULL)                                            \
00490         pbuf_free(p);                                           \
00491     }                                                           \
00492   } while (0)
00493 
00494 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
00495   do {                                                           \
00496     if((pcb)->connected != NULL)                                 \
00497       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
00498   } while (0)
00499 
00500 #define TCP_EVENT_POLL(pcb,ret)                                \
00501   do {                                                         \
00502     if((pcb)->poll != NULL)                                    \
00503       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
00504   } while (0)
00505 
00506 #define TCP_EVENT_ERR(errf,arg,err)                            \
00507   do {                                                         \
00508     if((errf) != NULL)                                         \
00509       (errf)((arg),(err));                                     \
00510   } while (0)
00511 
00512 #endif /* LWIP_EVENT_API */
00513 
00514 /* This structure represents a TCP segment on the unsent and unacked queues */
00515 struct tcp_seg {
00516   struct tcp_seg *next;    /* used when putting segements on a queue */
00517   struct pbuf *p;          /* buffer containing data + TCP header */
00518   void *dataptr;           /* pointer to the TCP data in the pbuf */
00519   u16_t len;               /* the TCP length of this segment */
00520   u8_t  flags;
00521 #define TF_SEG_OPTS_MSS   (u8_t)0x01U   /* Include MSS option. */
00522 #define TF_SEG_OPTS_TS    (u8_t)0x02U   /* Include timestamp option. */
00523   struct tcp_hdr *tcphdr;  /* the TCP header */
00524 };
00525 
00526 #define LWIP_TCP_OPT_LENGTH(flags)              \
00527   (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
00528   (flags & TF_SEG_OPTS_TS  ? 12 : 0)
00529 
00530 /** This returns a TCP header option for MSS in an u32_t */
00531 #define TCP_BUILD_MSS_OPTION(x) (x) = htonl(((u32_t)2 << 24) |          \
00532                                             ((u32_t)4 << 16) |          \
00533                                             (((u32_t)TCP_MSS / 256) << 8) | \
00534                                             (TCP_MSS & 255))
00535 
00536 /* Internal functions and global variables: */
00537 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
00538 void tcp_pcb_purge(struct tcp_pcb *pcb);
00539 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
00540 
00541 u8_t tcp_segs_free(struct tcp_seg *seg);
00542 u8_t tcp_seg_free(struct tcp_seg *seg);
00543 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
00544 
00545 #define tcp_ack(pcb)                               \
00546   do {                                             \
00547     if((pcb)->flags & TF_ACK_DELAY) {              \
00548       (pcb)->flags &= ~TF_ACK_DELAY;               \
00549       (pcb)->flags |= TF_ACK_NOW;                  \
00550       tcp_output(pcb);                             \
00551     }                                              \
00552     else {                                         \
00553       (pcb)->flags |= TF_ACK_DELAY;                \
00554     }                                              \
00555   } while (0)
00556 
00557 #define tcp_ack_now(pcb)                           \
00558   do {                                             \
00559     (pcb)->flags |= TF_ACK_NOW;                    \
00560     tcp_output(pcb);                               \
00561   } while (0)
00562 
00563 err_t tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags);
00564 err_t tcp_enqueue(struct tcp_pcb *pcb, void *dataptr, u16_t len,
00565                   u8_t flags, u8_t apiflags, u8_t optflags);
00566 
00567 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
00568 
00569 void tcp_rst(u32_t seqno, u32_t ackno,
00570        struct ip_addr *local_ip, struct ip_addr *remote_ip,
00571        u16_t local_port, u16_t remote_port);
00572 
00573 u32_t tcp_next_iss(void);
00574 
00575 void tcp_keepalive(struct tcp_pcb *pcb);
00576 void tcp_zero_window_probe(struct tcp_pcb *pcb);
00577 
00578 #if TCP_CALCULATE_EFF_SEND_MSS
00579 u16_t tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr);
00580 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
00581 
00582 extern struct tcp_pcb *tcp_input_pcb;
00583 extern u32_t tcp_ticks;
00584 
00585 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
00586 void tcp_debug_print(struct tcp_hdr *tcphdr);
00587 void tcp_debug_print_flags(u8_t flags);
00588 void tcp_debug_print_state(enum tcp_state s);
00589 void tcp_debug_print_pcbs(void);
00590 s16_t tcp_pcbs_sane(void);
00591 #else
00592 #  define tcp_debug_print(tcphdr)
00593 #  define tcp_debug_print_flags(flags)
00594 #  define tcp_debug_print_state(s)
00595 #  define tcp_debug_print_pcbs()
00596 #  define tcp_pcbs_sane() 1
00597 #endif /* TCP_DEBUG */
00598 
00599 #if NO_SYS
00600 #define tcp_timer_needed()
00601 #else
00602 void tcp_timer_needed(void);
00603 #endif
00604 
00605 /* The TCP PCB lists. */
00606 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
00607   struct tcp_pcb_listen *listen_pcbs; 
00608   struct tcp_pcb *pcbs;
00609 };
00610 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
00611 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
00612               state in which they accept or send
00613               data. */
00614 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
00615 
00616 extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */
00617 
00618 /* Axioms about the above lists:   
00619    1) Every TCP PCB that is not CLOSED is in one of the lists.
00620    2) A PCB is only in one of the lists.
00621    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
00622    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
00623 */
00624 
00625 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
00626    with a PCB list or removes a PCB from a list, respectively. */
00627 #if 0
00628 #define TCP_REG(pcbs, npcb) do {\
00629                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \
00630                             for(tcp_tmp_pcb = *pcbs; \
00631           tcp_tmp_pcb != NULL; \
00632         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00633                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
00634                             } \
00635                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
00636                             npcb->next = *pcbs; \
00637                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
00638                             *(pcbs) = npcb; \
00639                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00640               tcp_timer_needed(); \
00641                             } while(0)
00642 #define TCP_RMV(pcbs, npcb) do { \
00643                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
00644                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \
00645                             if(*pcbs == npcb) { \
00646                                *pcbs = (*pcbs)->next; \
00647                             } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00648                                if(tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) { \
00649                                   tcp_tmp_pcb->next = npcb->next; \
00650                                   break; \
00651                                } \
00652                             } \
00653                             npcb->next = NULL; \
00654                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00655                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \
00656                             } while(0)
00657 
00658 #else /* LWIP_DEBUG */
00659 
00660 #define TCP_REG(pcbs, npcb)                        \
00661   do {                                             \
00662     npcb->next = *pcbs;                            \
00663     *(pcbs) = npcb;                                \
00664     tcp_timer_needed();                            \
00665   } while (0)
00666 
00667 #define TCP_RMV(pcbs, npcb)                        \
00668   do {                                             \
00669     if(*(pcbs) == npcb) {                          \
00670       (*(pcbs)) = (*pcbs)->next;                   \
00671     }                                              \
00672     else {                                         \
00673       for(tcp_tmp_pcb = *pcbs;                                         \
00674           tcp_tmp_pcb != NULL;                                         \
00675           tcp_tmp_pcb = tcp_tmp_pcb->next) {                           \
00676         if(tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) {   \
00677           tcp_tmp_pcb->next = npcb->next;          \
00678           break;                                   \
00679         }                                          \
00680       }                                            \
00681     }                                              \
00682     npcb->next = NULL;                             \
00683   } while(0)
00684 
00685 #endif /* LWIP_DEBUG */
00686 
00687 #ifdef __cplusplus
00688 }
00689 #endif
00690 
00691 #endif /* LWIP_TCP */
00692 
00693 #endif /* __LWIP_TCP_H__ */