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_free    (struct tcp_pcb *pcb);
00081 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
00082 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
00083 err_t            tcp_rexmit  (struct tcp_pcb *pcb);
00084 err_t            tcp_rexmit_rto_prepare(struct tcp_pcb *pcb);
00085 void             tcp_rexmit_rto_commit(struct tcp_pcb *pcb);
00086 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
00087 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
00088 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
00089 err_t            tcp_process_refused_data(struct tcp_pcb *pcb);
00090 
00091 /**
00092  * This is the Nagle algorithm: try to combine user data to send as few TCP
00093  * segments as possible. Only send if
00094  * - no previously transmitted data on the connection remains unacknowledged or
00095  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
00096  * - the only unsent segment is at least pcb->mss bytes long (or there is more
00097  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
00098  * - or if we are in fast-retransmit (TF_INFR)
00099  */
00100 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
00101                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
00102                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
00103                               ((tpcb)->unsent->len >= (tpcb)->mss))) || \
00104                             ((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \
00105                             ) ? 1 : 0)
00106 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
00107 
00108 
00109 #define TCP_SEQ_LT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0)
00110 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0)
00111 #define TCP_SEQ_GT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0)
00112 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0)
00113 /* is b<=a<=c? */
00114 #if 0 /* see bug #10548 */
00115 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
00116 #endif
00117 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
00118 
00119 #ifndef TCP_TMR_INTERVAL
00120 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
00121 #endif /* TCP_TMR_INTERVAL */
00122 
00123 #ifndef TCP_FAST_INTERVAL
00124 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
00125 #endif /* TCP_FAST_INTERVAL */
00126 
00127 #ifndef TCP_SLOW_INTERVAL
00128 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
00129 #endif /* TCP_SLOW_INTERVAL */
00130 
00131 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
00132 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
00133 
00134 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
00135 
00136 #ifndef TCP_MSL
00137 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
00138 #endif
00139 
00140 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
00141 #ifndef  TCP_KEEPIDLE_DEFAULT
00142 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
00143 #endif
00144 
00145 #ifndef  TCP_KEEPINTVL_DEFAULT
00146 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
00147 #endif
00148 
00149 #ifndef  TCP_KEEPCNT_DEFAULT
00150 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
00151 #endif
00152 
00153 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
00154 
00155 #define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U))
00156 
00157 /** Flags used on input processing, not on pcb->flags
00158 */
00159 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
00160 #define TF_CLOSED    (u8_t)0x10U   /* Connection was successfully closed. */
00161 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
00162 
00163 
00164 #if LWIP_EVENT_API
00165 
00166 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) ret = lwip_tcp_event(arg, (pcb),\
00167                 LWIP_EVENT_ACCEPT, NULL, 0, err)
00168 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00169                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
00170 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00171                 LWIP_EVENT_RECV, (p), 0, (err))
00172 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00173                 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
00174 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00175                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
00176 #define TCP_EVENT_POLL(pcb,ret)       do { if ((pcb)->state != SYN_RCVD) {                          \
00177                 ret = lwip_tcp_event((pcb)->callback_arg, (pcb), LWIP_EVENT_POLL, NULL, 0, ERR_OK); \
00178                 } else {                                                                            \
00179                 ret = ERR_ARG; } } while(0)
00180 /* For event API, last state SYN_RCVD must be excluded here: the application
00181    has not seen this pcb, yet! */
00182 #define TCP_EVENT_ERR(last_state,errf,arg,err)  do { if (last_state != SYN_RCVD) {                \
00183                 lwip_tcp_event((arg), NULL, LWIP_EVENT_ERR, NULL, 0, (err)); } } while(0)
00184 
00185 #else /* LWIP_EVENT_API */
00186 
00187 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret)                 \
00188   do {                                                         \
00189     if((lpcb)->accept != NULL)                                 \
00190       (ret) = (lpcb)->accept((arg),(pcb),(err));               \
00191     else (ret) = ERR_ARG;                                      \
00192   } while (0)
00193 
00194 #define TCP_EVENT_SENT(pcb,space,ret)                          \
00195   do {                                                         \
00196     if((pcb)->sent != NULL)                                    \
00197       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
00198     else (ret) = ERR_OK;                                       \
00199   } while (0)
00200 
00201 #define TCP_EVENT_RECV(pcb,p,err,ret)                          \
00202   do {                                                         \
00203     if((pcb)->recv != NULL) {                                  \
00204       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
00205     } else {                                                   \
00206       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
00207     }                                                          \
00208   } while (0)
00209 
00210 #define TCP_EVENT_CLOSED(pcb,ret)                                \
00211   do {                                                           \
00212     if(((pcb)->recv != NULL)) {                                  \
00213       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
00214     } else {                                                     \
00215       (ret) = ERR_OK;                                            \
00216     }                                                            \
00217   } while (0)
00218 
00219 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
00220   do {                                                           \
00221     if((pcb)->connected != NULL)                                 \
00222       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
00223     else (ret) = ERR_OK;                                         \
00224   } while (0)
00225 
00226 #define TCP_EVENT_POLL(pcb,ret)                                \
00227   do {                                                         \
00228     if((pcb)->poll != NULL)                                    \
00229       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
00230     else (ret) = ERR_OK;                                       \
00231   } while (0)
00232 
00233 #define TCP_EVENT_ERR(last_state,errf,arg,err)                 \
00234   do {                                                         \
00235     LWIP_UNUSED_ARG(last_state);                               \
00236     if((errf) != NULL)                                         \
00237       (errf)((arg),(err));                                     \
00238   } while (0)
00239 
00240 #endif /* LWIP_EVENT_API */
00241 
00242 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
00243 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
00244 #define TCP_OVERSIZE_DBGCHECK 1
00245 #else
00246 #define TCP_OVERSIZE_DBGCHECK 0
00247 #endif
00248 
00249 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
00250 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
00251 
00252 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
00253 struct tcp_seg {
00254   struct tcp_seg *next;    /* used when putting segments on a queue */
00255   struct pbuf *p;          /* buffer containing data + TCP header */
00256   u16_t len;               /* the TCP length of this segment */
00257 #if TCP_OVERSIZE_DBGCHECK
00258   u16_t oversize_left;     /* Extra bytes available at the end of the last
00259                               pbuf in unsent (used for asserting vs.
00260                               tcp_pcb.unsent_oversize only) */
00261 #endif /* TCP_OVERSIZE_DBGCHECK */
00262 #if TCP_CHECKSUM_ON_COPY
00263   u16_t chksum;
00264   u8_t  chksum_swapped;
00265 #endif /* TCP_CHECKSUM_ON_COPY */
00266   u8_t  flags;
00267 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option (only used in SYN segments) */
00268 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
00269 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
00270                                                checksummed into 'chksum' */
00271 #define TF_SEG_OPTS_WND_SCALE   (u8_t)0x08U /* Include WND SCALE option (only used in SYN segments) */
00272 #define TF_SEG_OPTS_SACK_PERM   (u8_t)0x10U /* Include SACK Permitted option (only used in SYN segments) */
00273   struct tcp_hdr *tcphdr;  /* the TCP header */
00274 };
00275 
00276 #define LWIP_TCP_OPT_EOL        0
00277 #define LWIP_TCP_OPT_NOP        1
00278 #define LWIP_TCP_OPT_MSS        2
00279 #define LWIP_TCP_OPT_WS         3
00280 #define LWIP_TCP_OPT_SACK_PERM  4
00281 #define LWIP_TCP_OPT_TS         8
00282 
00283 #define LWIP_TCP_OPT_LEN_MSS    4
00284 #if LWIP_TCP_TIMESTAMPS
00285 #define LWIP_TCP_OPT_LEN_TS     10
00286 #define LWIP_TCP_OPT_LEN_TS_OUT 12 /* aligned for output (includes NOP padding) */
00287 #else
00288 #define LWIP_TCP_OPT_LEN_TS_OUT 0
00289 #endif
00290 #if LWIP_WND_SCALE
00291 #define LWIP_TCP_OPT_LEN_WS     3
00292 #define LWIP_TCP_OPT_LEN_WS_OUT 4 /* aligned for output (includes NOP padding) */
00293 #else
00294 #define LWIP_TCP_OPT_LEN_WS_OUT 0
00295 #endif
00296 
00297 #if LWIP_TCP_SACK_OUT
00298 #define LWIP_TCP_OPT_LEN_SACK_PERM     2
00299 #define LWIP_TCP_OPT_LEN_SACK_PERM_OUT 4 /* aligned for output (includes NOP padding) */
00300 #else
00301 #define LWIP_TCP_OPT_LEN_SACK_PERM_OUT 0
00302 #endif
00303 
00304 #define LWIP_TCP_OPT_LENGTH(flags) \
00305   ((flags) & TF_SEG_OPTS_MSS       ? LWIP_TCP_OPT_LEN_MSS           : 0) + \
00306   ((flags) & TF_SEG_OPTS_TS        ? LWIP_TCP_OPT_LEN_TS_OUT        : 0) + \
00307   ((flags) & TF_SEG_OPTS_WND_SCALE ? LWIP_TCP_OPT_LEN_WS_OUT        : 0) + \
00308   ((flags) & TF_SEG_OPTS_SACK_PERM ? LWIP_TCP_OPT_LEN_SACK_PERM_OUT : 0)
00309 
00310 /** This returns a TCP header option for MSS in an u32_t */
00311 #define TCP_BUILD_MSS_OPTION(mss) lwip_htonl(0x02040000 | ((mss) & 0xFFFF))
00312 
00313 #if LWIP_WND_SCALE
00314 #define TCPWNDSIZE_F       U32_F
00315 #define TCPWND_MAX         0xFFFFFFFFU
00316 #define TCPWND_CHECK16(x)  LWIP_ASSERT("window size > 0xFFFF", (x) <= 0xFFFF)
00317 #define TCPWND_MIN16(x)    ((u16_t)LWIP_MIN((x), 0xFFFF))
00318 #else /* LWIP_WND_SCALE */
00319 #define TCPWNDSIZE_F       U16_F
00320 #define TCPWND_MAX         0xFFFFU
00321 #define TCPWND_CHECK16(x)
00322 #define TCPWND_MIN16(x)    x
00323 #endif /* LWIP_WND_SCALE */
00324 
00325 /* Global variables: */
00326 extern struct tcp_pcb *tcp_input_pcb;
00327 extern u32_t tcp_ticks;
00328 extern u8_t tcp_active_pcbs_changed;
00329 
00330 /* The TCP PCB lists. */
00331 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
00332   struct tcp_pcb_listen *listen_pcbs;
00333   struct tcp_pcb *pcbs;
00334 };
00335 extern struct tcp_pcb *tcp_bound_pcbs;
00336 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
00337 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
00338               state in which they accept or send
00339               data. */
00340 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
00341 
00342 #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT  3
00343 #define NUM_TCP_PCB_LISTS               4
00344 extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS];
00345 
00346 /* Axioms about the above lists:
00347    1) Every TCP PCB that is not CLOSED is in one of the lists.
00348    2) A PCB is only in one of the lists.
00349    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
00350    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
00351 */
00352 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
00353    with a PCB list or removes a PCB from a list, respectively. */
00354 #ifndef TCP_DEBUG_PCB_LISTS
00355 #define TCP_DEBUG_PCB_LISTS 0
00356 #endif
00357 #if TCP_DEBUG_PCB_LISTS
00358 #define TCP_REG(pcbs, npcb) do {\
00359                             struct tcp_pcb *tcp_tmp_pcb; \
00360                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %"U16_F"\n", (void *)(npcb), (npcb)->local_port)); \
00361                             for (tcp_tmp_pcb = *(pcbs); \
00362           tcp_tmp_pcb != NULL; \
00363         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00364                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
00365                             } \
00366                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
00367                             (npcb)->next = *(pcbs); \
00368                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
00369                             *(pcbs) = (npcb); \
00370                             LWIP_ASSERT("TCP_REG: tcp_pcbs sane", tcp_pcbs_sane()); \
00371               tcp_timer_needed(); \
00372                             } while(0)
00373 #define TCP_RMV(pcbs, npcb) do { \
00374                             struct tcp_pcb *tcp_tmp_pcb; \
00375                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
00376                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (void *)(npcb), (void *)(*(pcbs)))); \
00377                             if(*(pcbs) == (npcb)) { \
00378                                *(pcbs) = (*pcbs)->next; \
00379                             } else for (tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00380                                if(tcp_tmp_pcb->next == (npcb)) { \
00381                                   tcp_tmp_pcb->next = (npcb)->next; \
00382                                   break; \
00383                                } \
00384                             } \
00385                             (npcb)->next = NULL; \
00386                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00387                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (void *)(npcb), (void *)(*(pcbs)))); \
00388                             } while(0)
00389 
00390 #else /* LWIP_DEBUG */
00391 
00392 #define TCP_REG(pcbs, npcb)                        \
00393   do {                                             \
00394     (npcb)->next = *pcbs;                          \
00395     *(pcbs) = (npcb);                              \
00396     tcp_timer_needed();                            \
00397   } while (0)
00398 
00399 #define TCP_RMV(pcbs, npcb)                        \
00400   do {                                             \
00401     if(*(pcbs) == (npcb)) {                        \
00402       (*(pcbs)) = (*pcbs)->next;                   \
00403     }                                              \
00404     else {                                         \
00405       struct tcp_pcb *tcp_tmp_pcb;                 \
00406       for (tcp_tmp_pcb = *pcbs;                    \
00407           tcp_tmp_pcb != NULL;                     \
00408           tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
00409         if(tcp_tmp_pcb->next == (npcb)) {          \
00410           tcp_tmp_pcb->next = (npcb)->next;        \
00411           break;                                   \
00412         }                                          \
00413       }                                            \
00414     }                                              \
00415     (npcb)->next = NULL;                           \
00416   } while(0)
00417 
00418 #endif /* LWIP_DEBUG */
00419 
00420 #define TCP_REG_ACTIVE(npcb)                       \
00421   do {                                             \
00422     TCP_REG(&tcp_active_pcbs, npcb);               \
00423     tcp_active_pcbs_changed = 1;                   \
00424   } while (0)
00425 
00426 #define TCP_RMV_ACTIVE(npcb)                       \
00427   do {                                             \
00428     TCP_RMV(&tcp_active_pcbs, npcb);               \
00429     tcp_active_pcbs_changed = 1;                   \
00430   } while (0)
00431 
00432 #define TCP_PCB_REMOVE_ACTIVE(pcb)                 \
00433   do {                                             \
00434     tcp_pcb_remove(&tcp_active_pcbs, pcb);         \
00435     tcp_active_pcbs_changed = 1;                   \
00436   } while (0)
00437 
00438 
00439 /* Internal functions: */
00440 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
00441 void tcp_pcb_purge(struct tcp_pcb *pcb);
00442 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
00443 
00444 void tcp_segs_free(struct tcp_seg *seg);
00445 void tcp_seg_free(struct tcp_seg *seg);
00446 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
00447 
00448 #define tcp_ack(pcb)                               \
00449   do {                                             \
00450     if((pcb)->flags & TF_ACK_DELAY) {              \
00451       tcp_clear_flags(pcb, TF_ACK_DELAY);          \
00452       tcp_ack_now(pcb);                            \
00453     }                                              \
00454     else {                                         \
00455       tcp_set_flags(pcb, TF_ACK_DELAY);            \
00456     }                                              \
00457   } while (0)
00458 
00459 #define tcp_ack_now(pcb)                           \
00460   tcp_set_flags(pcb, TF_ACK_NOW)
00461 
00462 err_t tcp_send_fin(struct tcp_pcb *pcb);
00463 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
00464 
00465 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
00466 
00467 void tcp_rst(const struct tcp_pcb* pcb, u32_t seqno, u32_t ackno,
00468        const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
00469        u16_t local_port, u16_t remote_port);
00470 
00471 u32_t tcp_next_iss(struct tcp_pcb *pcb);
00472 
00473 err_t tcp_keepalive(struct tcp_pcb *pcb);
00474 err_t tcp_split_unsent_seg(struct tcp_pcb *pcb, u16_t split);
00475 err_t tcp_zero_window_probe(struct tcp_pcb *pcb);
00476 void  tcp_trigger_input_pcb_close(void);
00477 
00478 #if TCP_CALCULATE_EFF_SEND_MSS
00479 u16_t tcp_eff_send_mss_netif(u16_t sendmss, struct netif *outif,
00480                              const ip_addr_t *dest);
00481 #define tcp_eff_send_mss(sendmss, src, dest) \
00482     tcp_eff_send_mss_netif(sendmss, ip_route(src, dest), dest)
00483 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
00484 
00485 #if LWIP_CALLBACK_API
00486 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
00487 #endif /* LWIP_CALLBACK_API */
00488 
00489 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
00490 void tcp_debug_print(struct tcp_hdr *tcphdr);
00491 void tcp_debug_print_flags(u8_t flags);
00492 void tcp_debug_print_state(enum tcp_state s);
00493 void tcp_debug_print_pcbs(void);
00494 s16_t tcp_pcbs_sane(void);
00495 #else
00496 #  define tcp_debug_print(tcphdr)
00497 #  define tcp_debug_print_flags(flags)
00498 #  define tcp_debug_print_state(s)
00499 #  define tcp_debug_print_pcbs()
00500 #  define tcp_pcbs_sane() 1
00501 #endif /* TCP_DEBUG */
00502 
00503 /** External function (implemented in timers.c), called when TCP detects
00504  * that a timer is needed (i.e. active- or time-wait-pcb found). */
00505 void tcp_timer_needed(void);
00506 
00507 void tcp_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr);
00508 
00509 #if TCP_QUEUE_OOSEQ
00510 void tcp_free_ooseq(struct tcp_pcb *pcb);
00511 #endif
00512 
00513 #if LWIP_TCP_PCB_NUM_EXT_ARGS
00514 err_t tcp_ext_arg_invoke_callbacks_passive_open(struct tcp_pcb_listen *lpcb, struct tcp_pcb *cpcb);
00515 #endif
00516 
00517 #ifdef __cplusplus
00518 }
00519 #endif
00520 
00521 #endif /* LWIP_TCP */
00522 
00523 #endif /* LWIP_HDR_TCP_PRIV_H */