tcp_priv.h

00001 /**
00002  * @file
00003  * TCP internal implementations (do not use in application code)
00004  */
00005 
00006 /*
00007  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00008  * All rights reserved.
00009  *
00010  * Redistribution and use in source and binary forms, with or without modification,
00011  * are permitted provided that the following conditions are met:
00012  *
00013  * 1. Redistributions of source code must retain the above copyright notice,
00014  *    this list of conditions and the following disclaimer.
00015  * 2. Redistributions in binary form must reproduce the above copyright notice,
00016  *    this list of conditions and the following disclaimer in the documentation
00017  *    and/or other materials provided with the distribution.
00018  * 3. The name of the author may not be used to endorse or promote products
00019  *    derived from this software without specific prior written permission.
00020  *
00021  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00022  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00023  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00024  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00025  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00026  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00027  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00028  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00029  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00030  * OF SUCH DAMAGE.
00031  *
00032  * This file is part of the lwIP TCP/IP stack.
00033  *
00034  * Author: Adam Dunkels <adam@sics.se>
00035  *
00036  */
00037 #ifndef LWIP_HDR_TCP_PRIV_H
00038 #define LWIP_HDR_TCP_PRIV_H
00039 
00040 #include "lwip/opt.h"
00041 
00042 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
00043 
00044 #include "lwip/tcp.h"
00045 #include "lwip/mem.h"
00046 #include "lwip/pbuf.h"
00047 #include "lwip/ip.h"
00048 #include "lwip/icmp.h"
00049 #include "lwip/err.h"
00050 #include "lwip/ip6.h"
00051 #include "lwip/ip6_addr.h"
00052 #include "lwip/prot/tcp.h"
00053 
00054 #ifdef __cplusplus
00055 extern "C" {
00056 #endif
00057 
00058 /* Functions for interfacing with TCP: */
00059 
00060 /* Lower layer interface to TCP: */
00061 void             tcp_init    (void);  /* Initialize this module. */
00062 void             tcp_tmr     (void);  /* Must be called every
00063                                          TCP_TMR_INTERVAL
00064                                          ms. (Typically 250 ms). */
00065 /* It is also possible to call these two functions at the right
00066    intervals (instead of calling tcp_tmr()). */
00067 void             tcp_slowtmr (void);
00068 void             tcp_fasttmr (void);
00069 
00070 /* Call this from a netif driver (watch out for threading issues!) that has
00071    returned a memory error on transmit and now has free buffers to send more.
00072    This iterates all active pcbs that had an error and tries to call
00073    tcp_output, so use this with care as it might slow down the system. */
00074 void             tcp_txnow   (void);
00075 
00076 /* Only used by IP to pass a TCP segment to TCP: */
00077 void             tcp_input   (struct pbuf *p, struct netif *inp);
00078 /* Used within the TCP code only: */
00079 struct tcp_pcb * tcp_alloc   (u8_t prio);
00080 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
00081 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
00082 void             tcp_rexmit  (struct tcp_pcb *pcb);
00083 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
00084 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
00085 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
00086 err_t            tcp_process_refused_data(struct tcp_pcb *pcb);
00087 
00088 /**
00089  * This is the Nagle algorithm: try to combine user data to send as few TCP
00090  * segments as possible. Only send if
00091  * - no previously transmitted data on the connection remains unacknowledged or
00092  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
00093  * - the only unsent segment is at least pcb->mss bytes long (or there is more
00094  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
00095  * - or if we are in fast-retransmit (TF_INFR)
00096  */
00097 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
00098                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
00099                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
00100                               ((tpcb)->unsent->len >= (tpcb)->mss))) || \
00101                             ((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \
00102                             ) ? 1 : 0)
00103 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
00104 
00105 
00106 #define TCP_SEQ_LT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0)
00107 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0)
00108 #define TCP_SEQ_GT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0)
00109 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0)
00110 /* is b<=a<=c? */
00111 #if 0 /* see bug #10548 */
00112 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
00113 #endif
00114 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
00115 
00116 #ifndef TCP_TMR_INTERVAL
00117 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
00118 #endif /* TCP_TMR_INTERVAL */
00119 
00120 #ifndef TCP_FAST_INTERVAL
00121 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
00122 #endif /* TCP_FAST_INTERVAL */
00123 
00124 #ifndef TCP_SLOW_INTERVAL
00125 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
00126 #endif /* TCP_SLOW_INTERVAL */
00127 
00128 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
00129 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
00130 
00131 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
00132 
00133 #ifndef TCP_MSL
00134 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
00135 #endif
00136 
00137 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
00138 #ifndef  TCP_KEEPIDLE_DEFAULT
00139 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
00140 #endif
00141 
00142 #ifndef  TCP_KEEPINTVL_DEFAULT
00143 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
00144 #endif
00145 
00146 #ifndef  TCP_KEEPCNT_DEFAULT
00147 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
00148 #endif
00149 
00150 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
00151 
00152 #define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U))
00153 
00154 /** Flags used on input processing, not on pcb->flags
00155 */
00156 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
00157 #define TF_CLOSED    (u8_t)0x10U   /* Connection was successfully closed. */
00158 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
00159 
00160 
00161 #if LWIP_EVENT_API
00162 
00163 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) ret = lwip_tcp_event(arg, (pcb),\
00164                 LWIP_EVENT_ACCEPT, NULL, 0, err)
00165 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00166                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
00167 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00168                 LWIP_EVENT_RECV, (p), 0, (err))
00169 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00170                 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
00171 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00172                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
00173 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00174                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
00175 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
00176                 LWIP_EVENT_ERR, NULL, 0, (err))
00177 
00178 #else /* LWIP_EVENT_API */
00179 
00180 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret)                 \
00181   do {                                                         \
00182     if((lpcb != NULL) && ((lpcb)->accept != NULL))             \
00183       (ret) = (lpcb)->accept((arg),(pcb),(err));               \
00184     else (ret) = ERR_ARG;                                      \
00185   } while (0)
00186 
00187 #define TCP_EVENT_SENT(pcb,space,ret)                          \
00188   do {                                                         \
00189     if((pcb)->sent != NULL)                                    \
00190       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
00191     else (ret) = ERR_OK;                                       \
00192   } while (0)
00193 
00194 #define TCP_EVENT_RECV(pcb,p,err,ret)                          \
00195   do {                                                         \
00196     if((pcb)->recv != NULL) {                                  \
00197       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
00198     } else {                                                   \
00199       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
00200     }                                                          \
00201   } while (0)
00202 
00203 #define TCP_EVENT_CLOSED(pcb,ret)                                \
00204   do {                                                           \
00205     if(((pcb)->recv != NULL)) {                                  \
00206       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
00207     } else {                                                     \
00208       (ret) = ERR_OK;                                            \
00209     }                                                            \
00210   } while (0)
00211 
00212 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
00213   do {                                                           \
00214     if((pcb)->connected != NULL)                                 \
00215       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
00216     else (ret) = ERR_OK;                                         \
00217   } while (0)
00218 
00219 #define TCP_EVENT_POLL(pcb,ret)                                \
00220   do {                                                         \
00221     if((pcb)->poll != NULL)                                    \
00222       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
00223     else (ret) = ERR_OK;                                       \
00224   } while (0)
00225 
00226 #define TCP_EVENT_ERR(errf,arg,err)                            \
00227   do {                                                         \
00228     if((errf) != NULL)                                         \
00229       (errf)((arg),(err));                                     \
00230   } while (0)
00231 
00232 #endif /* LWIP_EVENT_API */
00233 
00234 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
00235 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
00236 #define TCP_OVERSIZE_DBGCHECK 1
00237 #else
00238 #define TCP_OVERSIZE_DBGCHECK 0
00239 #endif
00240 
00241 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
00242 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
00243 
00244 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
00245 struct tcp_seg {
00246   struct tcp_seg *next;    /* used when putting segments on a queue */
00247   struct pbuf *p;          /* buffer containing data + TCP header */
00248   u16_t len;               /* the TCP length of this segment */
00249 #if TCP_OVERSIZE_DBGCHECK
00250   u16_t oversize_left;     /* Extra bytes available at the end of the last
00251                               pbuf in unsent (used for asserting vs.
00252                               tcp_pcb.unsent_oversized only) */
00253 #endif /* TCP_OVERSIZE_DBGCHECK */
00254 #if TCP_CHECKSUM_ON_COPY
00255   u16_t chksum;
00256   u8_t  chksum_swapped;
00257 #endif /* TCP_CHECKSUM_ON_COPY */
00258   u8_t  flags;
00259 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option. */
00260 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
00261 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
00262                                                checksummed into 'chksum' */
00263 #define TF_SEG_OPTS_WND_SCALE   (u8_t)0x08U /* Include WND SCALE option */
00264   struct tcp_hdr *tcphdr;  /* the TCP header */
00265 };
00266 
00267 #define LWIP_TCP_OPT_EOL        0
00268 #define LWIP_TCP_OPT_NOP        1
00269 #define LWIP_TCP_OPT_MSS        2
00270 #define LWIP_TCP_OPT_WS         3
00271 #define LWIP_TCP_OPT_TS         8
00272 
00273 #define LWIP_TCP_OPT_LEN_MSS    4
00274 #if LWIP_TCP_TIMESTAMPS
00275 #define LWIP_TCP_OPT_LEN_TS     10
00276 #define LWIP_TCP_OPT_LEN_TS_OUT 12 /* aligned for output (includes NOP padding) */
00277 #else
00278 #define LWIP_TCP_OPT_LEN_TS_OUT 0
00279 #endif
00280 #if LWIP_WND_SCALE
00281 #define LWIP_TCP_OPT_LEN_WS     3
00282 #define LWIP_TCP_OPT_LEN_WS_OUT 4 /* aligned for output (includes NOP padding) */
00283 #else
00284 #define LWIP_TCP_OPT_LEN_WS_OUT 0
00285 #endif
00286 
00287 #define LWIP_TCP_OPT_LENGTH(flags) \
00288   (flags & TF_SEG_OPTS_MSS       ? LWIP_TCP_OPT_LEN_MSS    : 0) + \
00289   (flags & TF_SEG_OPTS_TS        ? LWIP_TCP_OPT_LEN_TS_OUT : 0) + \
00290   (flags & TF_SEG_OPTS_WND_SCALE ? LWIP_TCP_OPT_LEN_WS_OUT : 0)
00291 
00292 /** This returns a TCP header option for MSS in an u32_t */
00293 #define TCP_BUILD_MSS_OPTION(mss) lwip_htonl(0x02040000 | ((mss) & 0xFFFF))
00294 
00295 #if LWIP_WND_SCALE
00296 #define TCPWNDSIZE_F       U32_F
00297 #define TCPWND_MAX         0xFFFFFFFFU
00298 #define TCPWND_CHECK16(x)  LWIP_ASSERT("window size > 0xFFFF", (x) <= 0xFFFF)
00299 #define TCPWND_MIN16(x)    ((u16_t)LWIP_MIN((x), 0xFFFF))
00300 #else /* LWIP_WND_SCALE */
00301 #define TCPWNDSIZE_F       U16_F
00302 #define TCPWND_MAX         0xFFFFU
00303 #define TCPWND_CHECK16(x)
00304 #define TCPWND_MIN16(x)    x
00305 #endif /* LWIP_WND_SCALE */
00306 
00307 /* Global variables: */
00308 extern struct tcp_pcb *tcp_input_pcb;
00309 extern u32_t tcp_ticks;
00310 extern u8_t tcp_active_pcbs_changed;
00311 
00312 /* The TCP PCB lists. */
00313 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
00314   struct tcp_pcb_listen *listen_pcbs;
00315   struct tcp_pcb *pcbs;
00316 };
00317 extern struct tcp_pcb *tcp_bound_pcbs;
00318 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
00319 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
00320               state in which they accept or send
00321               data. */
00322 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
00323 
00324 #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT  3
00325 #define NUM_TCP_PCB_LISTS               4
00326 extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS];
00327 
00328 /* Axioms about the above lists:
00329    1) Every TCP PCB that is not CLOSED is in one of the lists.
00330    2) A PCB is only in one of the lists.
00331    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
00332    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
00333 */
00334 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
00335    with a PCB list or removes a PCB from a list, respectively. */
00336 #ifndef TCP_DEBUG_PCB_LISTS
00337 #define TCP_DEBUG_PCB_LISTS 0
00338 #endif
00339 #if TCP_DEBUG_PCB_LISTS
00340 #define TCP_REG(pcbs, npcb) do {\
00341                             struct tcp_pcb *tcp_tmp_pcb; \
00342                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
00343                             for (tcp_tmp_pcb = *(pcbs); \
00344           tcp_tmp_pcb != NULL; \
00345         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00346                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
00347                             } \
00348                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
00349                             (npcb)->next = *(pcbs); \
00350                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
00351                             *(pcbs) = (npcb); \
00352                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00353               tcp_timer_needed(); \
00354                             } while(0)
00355 #define TCP_RMV(pcbs, npcb) do { \
00356                             struct tcp_pcb *tcp_tmp_pcb; \
00357                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
00358                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
00359                             if(*(pcbs) == (npcb)) { \
00360                                *(pcbs) = (*pcbs)->next; \
00361                             } else for (tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00362                                if(tcp_tmp_pcb->next == (npcb)) { \
00363                                   tcp_tmp_pcb->next = (npcb)->next; \
00364                                   break; \
00365                                } \
00366                             } \
00367                             (npcb)->next = NULL; \
00368                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00369                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
00370                             } while(0)
00371 
00372 #else /* LWIP_DEBUG */
00373 
00374 #define TCP_REG(pcbs, npcb)                        \
00375   do {                                             \
00376     (npcb)->next = *pcbs;                          \
00377     *(pcbs) = (npcb);                              \
00378     tcp_timer_needed();                            \
00379   } while (0)
00380 
00381 #define TCP_RMV(pcbs, npcb)                        \
00382   do {                                             \
00383     if(*(pcbs) == (npcb)) {                        \
00384       (*(pcbs)) = (*pcbs)->next;                   \
00385     }                                              \
00386     else {                                         \
00387       struct tcp_pcb *tcp_tmp_pcb;                 \
00388       for (tcp_tmp_pcb = *pcbs;                    \
00389           tcp_tmp_pcb != NULL;                     \
00390           tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
00391         if(tcp_tmp_pcb->next == (npcb)) {          \
00392           tcp_tmp_pcb->next = (npcb)->next;        \
00393           break;                                   \
00394         }                                          \
00395       }                                            \
00396     }                                              \
00397     (npcb)->next = NULL;                           \
00398   } while(0)
00399 
00400 #endif /* LWIP_DEBUG */
00401 
00402 #define TCP_REG_ACTIVE(npcb)                       \
00403   do {                                             \
00404     TCP_REG(&tcp_active_pcbs, npcb);               \
00405     tcp_active_pcbs_changed = 1;                   \
00406   } while (0)
00407 
00408 #define TCP_RMV_ACTIVE(npcb)                       \
00409   do {                                             \
00410     TCP_RMV(&tcp_active_pcbs, npcb);               \
00411     tcp_active_pcbs_changed = 1;                   \
00412   } while (0)
00413 
00414 #define TCP_PCB_REMOVE_ACTIVE(pcb)                 \
00415   do {                                             \
00416     tcp_pcb_remove(&tcp_active_pcbs, pcb);         \
00417     tcp_active_pcbs_changed = 1;                   \
00418   } while (0)
00419 
00420 
00421 /* Internal functions: */
00422 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
00423 void tcp_pcb_purge(struct tcp_pcb *pcb);
00424 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
00425 
00426 void tcp_segs_free(struct tcp_seg *seg);
00427 void tcp_seg_free(struct tcp_seg *seg);
00428 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
00429 
00430 #define tcp_ack(pcb)                               \
00431   do {                                             \
00432     if((pcb)->flags & TF_ACK_DELAY) {              \
00433       (pcb)->flags &= ~TF_ACK_DELAY;               \
00434       (pcb)->flags |= TF_ACK_NOW;                  \
00435     }                                              \
00436     else {                                         \
00437       (pcb)->flags |= TF_ACK_DELAY;                \
00438     }                                              \
00439   } while (0)
00440 
00441 #define tcp_ack_now(pcb)                           \
00442   do {                                             \
00443     (pcb)->flags |= TF_ACK_NOW;                    \
00444   } while (0)
00445 
00446 err_t tcp_send_fin(struct tcp_pcb *pcb);
00447 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
00448 
00449 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
00450 
00451 void tcp_rst(u32_t seqno, u32_t ackno,
00452        const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
00453        u16_t local_port, u16_t remote_port);
00454 
00455 u32_t tcp_next_iss(struct tcp_pcb *pcb);
00456 
00457 err_t tcp_keepalive(struct tcp_pcb *pcb);
00458 err_t tcp_zero_window_probe(struct tcp_pcb *pcb);
00459 void  tcp_trigger_input_pcb_close(void);
00460 
00461 #if TCP_CALCULATE_EFF_SEND_MSS
00462 u16_t tcp_eff_send_mss_impl(u16_t sendmss, const ip_addr_t *dest
00463 #if LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING
00464                            , const ip_addr_t *src
00465 #endif /* LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING */
00466                            );
00467 #if LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING
00468 #define tcp_eff_send_mss(sendmss, src, dest) tcp_eff_send_mss_impl(sendmss, dest, src)
00469 #else /* LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING */
00470 #define tcp_eff_send_mss(sendmss, src, dest) tcp_eff_send_mss_impl(sendmss, dest)
00471 #endif /* LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING */
00472 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
00473 
00474 #if LWIP_CALLBACK_API
00475 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
00476 #endif /* LWIP_CALLBACK_API */
00477 
00478 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
00479 void tcp_debug_print(struct tcp_hdr *tcphdr);
00480 void tcp_debug_print_flags(u8_t flags);
00481 void tcp_debug_print_state(enum tcp_state s);
00482 void tcp_debug_print_pcbs(void);
00483 s16_t tcp_pcbs_sane(void);
00484 #else
00485 #  define tcp_debug_print(tcphdr)
00486 #  define tcp_debug_print_flags(flags)
00487 #  define tcp_debug_print_state(s)
00488 #  define tcp_debug_print_pcbs()
00489 #  define tcp_pcbs_sane() 1
00490 #endif /* TCP_DEBUG */
00491 
00492 /** External function (implemented in timers.c), called when TCP detects
00493  * that a timer is needed (i.e. active- or time-wait-pcb found). */
00494 void tcp_timer_needed(void);
00495 
00496 void tcp_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr);
00497 
00498 #ifdef __cplusplus
00499 }
00500 #endif
00501 
00502 #endif /* LWIP_TCP */
00503 
00504 #endif /* LWIP_HDR_TCP_PRIV_H */