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_IMPL_H
00038 #define LWIP_HDR_TCP_IMPL_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 
00053 #ifdef __cplusplus
00054 extern "C" {
00055 #endif
00056 
00057 /* Functions for interfacing with TCP: */
00058 
00059 /* Lower layer interface to TCP: */
00060 void             tcp_init    (void);  /* Initialize this module. */
00061 void             tcp_tmr     (void);  /* Must be called every
00062                                          TCP_TMR_INTERVAL
00063                                          ms. (Typically 250 ms). */
00064 /* It is also possible to call these two functions at the right
00065    intervals (instead of calling tcp_tmr()). */
00066 void             tcp_slowtmr (void);
00067 void             tcp_fasttmr (void);
00068 
00069 /* Call this from a netif driver (watch out for threading issues!) that has
00070    returned a memory error on transmit and now has free buffers to send more.
00071    This iterates all active pcbs that had an error and tries to call
00072    tcp_output, so use this with care as it might slow down the system. */
00073 void             tcp_txnow   (void);
00074 
00075 /* Only used by IP to pass a TCP segment to TCP: */
00076 void             tcp_input   (struct pbuf *p, struct netif *inp);
00077 /* Used within the TCP code only: */
00078 struct tcp_pcb * tcp_alloc   (u8_t prio);
00079 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
00080 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
00081 void             tcp_rexmit  (struct tcp_pcb *pcb);
00082 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
00083 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
00084 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
00085 err_t            tcp_process_refused_data(struct tcp_pcb *pcb);
00086 
00087 /**
00088  * This is the Nagle algorithm: try to combine user data to send as few TCP
00089  * segments as possible. Only send if
00090  * - no previously transmitted data on the connection remains unacknowledged or
00091  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
00092  * - the only unsent segment is at least pcb->mss bytes long (or there is more
00093  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
00094  * - or if we are in fast-retransmit (TF_INFR)
00095  */
00096 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
00097                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
00098                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
00099                               ((tpcb)->unsent->len >= (tpcb)->mss))) || \
00100                             ((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \
00101                             ) ? 1 : 0)
00102 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
00103 
00104 
00105 #define TCP_SEQ_LT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0)
00106 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0)
00107 #define TCP_SEQ_GT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0)
00108 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0)
00109 /* is b<=a<=c? */
00110 #if 0 /* see bug #10548 */
00111 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
00112 #endif
00113 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
00114 #define TCP_FIN 0x01U
00115 #define TCP_SYN 0x02U
00116 #define TCP_RST 0x04U
00117 #define TCP_PSH 0x08U
00118 #define TCP_ACK 0x10U
00119 #define TCP_URG 0x20U
00120 #define TCP_ECE 0x40U
00121 #define TCP_CWR 0x80U
00122 
00123 #define TCP_FLAGS 0x3fU
00124 
00125 /* Length of the TCP header, excluding options. */
00126 #define TCP_HLEN 20
00127 
00128 #ifndef TCP_TMR_INTERVAL
00129 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
00130 #endif /* TCP_TMR_INTERVAL */
00131 
00132 #ifndef TCP_FAST_INTERVAL
00133 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
00134 #endif /* TCP_FAST_INTERVAL */
00135 
00136 #ifndef TCP_SLOW_INTERVAL
00137 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
00138 #endif /* TCP_SLOW_INTERVAL */
00139 
00140 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
00141 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
00142 
00143 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
00144 
00145 #ifndef TCP_MSL
00146 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
00147 #endif
00148 
00149 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
00150 #ifndef  TCP_KEEPIDLE_DEFAULT
00151 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
00152 #endif
00153 
00154 #ifndef  TCP_KEEPINTVL_DEFAULT
00155 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
00156 #endif
00157 
00158 #ifndef  TCP_KEEPCNT_DEFAULT
00159 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
00160 #endif
00161 
00162 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
00163 
00164 /* Fields are (of course) in network byte order.
00165  * Some fields are converted to host byte order in tcp_input().
00166  */
00167 #ifdef PACK_STRUCT_USE_INCLUDES
00168 #  include "arch/bpstruct.h"
00169 #endif
00170 PACK_STRUCT_BEGIN
00171 struct tcp_hdr {
00172   PACK_STRUCT_FIELD(u16_t src);
00173   PACK_STRUCT_FIELD(u16_t dest);
00174   PACK_STRUCT_FIELD(u32_t seqno);
00175   PACK_STRUCT_FIELD(u32_t ackno);
00176   PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
00177   PACK_STRUCT_FIELD(u16_t wnd);
00178   PACK_STRUCT_FIELD(u16_t chksum);
00179   PACK_STRUCT_FIELD(u16_t urgp);
00180 } PACK_STRUCT_STRUCT;
00181 PACK_STRUCT_END
00182 #ifdef PACK_STRUCT_USE_INCLUDES
00183 #  include "arch/epstruct.h"
00184 #endif
00185 
00186 #define TCPH_HDRLEN(phdr) ((u16_t)(ntohs((phdr)->_hdrlen_rsvd_flags) >> 12))
00187 #define TCPH_FLAGS(phdr)  ((u16_t)(ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS))
00188 
00189 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
00190 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & PP_HTONS(~TCP_FLAGS)) | htons(flags))
00191 #define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags))
00192 
00193 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
00194 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags & ~htons(flags))
00195 
00196 #define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U))
00197 
00198 /** Flags used on input processing, not on pcb->flags
00199 */
00200 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
00201 #define TF_CLOSED    (u8_t)0x10U   /* Connection was successfully closed. */
00202 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
00203 
00204 
00205 #if LWIP_EVENT_API
00206 
00207 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) ret = lwip_tcp_event(arg, (pcb),\
00208                 LWIP_EVENT_ACCEPT, NULL, 0, err)
00209 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00210                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
00211 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00212                 LWIP_EVENT_RECV, (p), 0, (err))
00213 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00214                 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
00215 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00216                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
00217 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00218                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
00219 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
00220                 LWIP_EVENT_ERR, NULL, 0, (err))
00221 
00222 #else /* LWIP_EVENT_API */
00223 
00224 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret)                 \
00225   do {                                                         \
00226     if((lpcb != NULL) && ((lpcb)->accept != NULL))             \
00227       (ret) = (lpcb)->accept((arg),(pcb),(err));               \
00228     else (ret) = ERR_ARG;                                      \
00229   } while (0)
00230 
00231 #define TCP_EVENT_SENT(pcb,space,ret)                          \
00232   do {                                                         \
00233     if((pcb)->sent != NULL)                                    \
00234       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
00235     else (ret) = ERR_OK;                                       \
00236   } while (0)
00237 
00238 #define TCP_EVENT_RECV(pcb,p,err,ret)                          \
00239   do {                                                         \
00240     if((pcb)->recv != NULL) {                                  \
00241       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
00242     } else {                                                   \
00243       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
00244     }                                                          \
00245   } while (0)
00246 
00247 #define TCP_EVENT_CLOSED(pcb,ret)                                \
00248   do {                                                           \
00249     if(((pcb)->recv != NULL)) {                                  \
00250       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
00251     } else {                                                     \
00252       (ret) = ERR_OK;                                            \
00253     }                                                            \
00254   } while (0)
00255 
00256 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
00257   do {                                                           \
00258     if((pcb)->connected != NULL)                                 \
00259       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
00260     else (ret) = ERR_OK;                                         \
00261   } while (0)
00262 
00263 #define TCP_EVENT_POLL(pcb,ret)                                \
00264   do {                                                         \
00265     if((pcb)->poll != NULL)                                    \
00266       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
00267     else (ret) = ERR_OK;                                       \
00268   } while (0)
00269 
00270 #define TCP_EVENT_ERR(errf,arg,err)                            \
00271   do {                                                         \
00272     if((errf) != NULL)                                         \
00273       (errf)((arg),(err));                                     \
00274   } while (0)
00275 
00276 #endif /* LWIP_EVENT_API */
00277 
00278 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
00279 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
00280 #define TCP_OVERSIZE_DBGCHECK 1
00281 #else
00282 #define TCP_OVERSIZE_DBGCHECK 0
00283 #endif
00284 
00285 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
00286 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
00287 
00288 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
00289 struct tcp_seg {
00290   struct tcp_seg *next;    /* used when putting segments on a queue */
00291   struct pbuf *p;          /* buffer containing data + TCP header */
00292   u16_t len;               /* the TCP length of this segment */
00293 #if TCP_OVERSIZE_DBGCHECK
00294   u16_t oversize_left;     /* Extra bytes available at the end of the last
00295                               pbuf in unsent (used for asserting vs.
00296                               tcp_pcb.unsent_oversized only) */
00297 #endif /* TCP_OVERSIZE_DBGCHECK */
00298 #if TCP_CHECKSUM_ON_COPY
00299   u16_t chksum;
00300   u8_t  chksum_swapped;
00301 #endif /* TCP_CHECKSUM_ON_COPY */
00302   u8_t  flags;
00303 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option. */
00304 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
00305 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
00306                                                checksummed into 'chksum' */
00307 #define TF_SEG_OPTS_WND_SCALE   (u8_t)0x08U /* Include WND SCALE option */
00308   struct tcp_hdr *tcphdr;  /* the TCP header */
00309 };
00310 
00311 #define LWIP_TCP_OPT_EOL        0
00312 #define LWIP_TCP_OPT_NOP        1
00313 #define LWIP_TCP_OPT_MSS        2
00314 #define LWIP_TCP_OPT_WS         3
00315 #define LWIP_TCP_OPT_TS         8
00316 
00317 #define LWIP_TCP_OPT_LEN_MSS    4
00318 #if LWIP_TCP_TIMESTAMPS
00319 #define LWIP_TCP_OPT_LEN_TS     10
00320 #define LWIP_TCP_OPT_LEN_TS_OUT 12 /* aligned for output (includes NOP padding) */
00321 #else
00322 #define LWIP_TCP_OPT_LEN_TS_OUT 0
00323 #endif
00324 #if LWIP_WND_SCALE
00325 #define LWIP_TCP_OPT_LEN_WS     3
00326 #define LWIP_TCP_OPT_LEN_WS_OUT 4 /* aligned for output (includes NOP padding) */
00327 #else
00328 #define LWIP_TCP_OPT_LEN_WS_OUT 0
00329 #endif
00330 
00331 #define LWIP_TCP_OPT_LENGTH(flags) \
00332   (flags & TF_SEG_OPTS_MSS       ? LWIP_TCP_OPT_LEN_MSS    : 0) + \
00333   (flags & TF_SEG_OPTS_TS        ? LWIP_TCP_OPT_LEN_TS_OUT : 0) + \
00334   (flags & TF_SEG_OPTS_WND_SCALE ? LWIP_TCP_OPT_LEN_WS_OUT : 0)
00335 
00336 /** This returns a TCP header option for MSS in an u32_t */
00337 #define TCP_BUILD_MSS_OPTION(mss) htonl(0x02040000 | ((mss) & 0xFFFF))
00338 
00339 #if LWIP_WND_SCALE
00340 #define TCPWNDSIZE_F       U32_F
00341 #define TCPWND_MAX         0xFFFFFFFFU
00342 #define TCPWND_CHECK16(x)  LWIP_ASSERT("window size > 0xFFFF", (x) <= 0xFFFF)
00343 #define TCPWND_MIN16(x)    ((u16_t)LWIP_MIN((x), 0xFFFF))
00344 #else /* LWIP_WND_SCALE */
00345 #define TCPWNDSIZE_F       U16_F
00346 #define TCPWND_MAX         0xFFFFU
00347 #define TCPWND_CHECK16(x)
00348 #define TCPWND_MIN16(x)    x
00349 #endif /* LWIP_WND_SCALE */
00350 
00351 /* Global variables: */
00352 extern struct tcp_pcb *tcp_input_pcb;
00353 extern u32_t tcp_ticks;
00354 extern u8_t tcp_active_pcbs_changed;
00355 
00356 /* The TCP PCB lists. */
00357 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
00358   struct tcp_pcb_listen *listen_pcbs;
00359   struct tcp_pcb *pcbs;
00360 };
00361 extern struct tcp_pcb *tcp_bound_pcbs;
00362 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
00363 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
00364               state in which they accept or send
00365               data. */
00366 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
00367 
00368 #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT  3
00369 #define NUM_TCP_PCB_LISTS               4
00370 extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS];
00371 
00372 /* Axioms about the above lists:
00373    1) Every TCP PCB that is not CLOSED is in one of the lists.
00374    2) A PCB is only in one of the lists.
00375    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
00376    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
00377 */
00378 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
00379    with a PCB list or removes a PCB from a list, respectively. */
00380 #ifndef TCP_DEBUG_PCB_LISTS
00381 #define TCP_DEBUG_PCB_LISTS 0
00382 #endif
00383 #if TCP_DEBUG_PCB_LISTS
00384 #define TCP_REG(pcbs, npcb) do {\
00385                             struct tcp_pcb *tcp_tmp_pcb; \
00386                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
00387                             for (tcp_tmp_pcb = *(pcbs); \
00388           tcp_tmp_pcb != NULL; \
00389         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00390                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
00391                             } \
00392                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
00393                             (npcb)->next = *(pcbs); \
00394                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
00395                             *(pcbs) = (npcb); \
00396                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00397               tcp_timer_needed(); \
00398                             } while(0)
00399 #define TCP_RMV(pcbs, npcb) do { \
00400                             struct tcp_pcb *tcp_tmp_pcb; \
00401                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
00402                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
00403                             if(*(pcbs) == (npcb)) { \
00404                                *(pcbs) = (*pcbs)->next; \
00405                             } else for (tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00406                                if(tcp_tmp_pcb->next == (npcb)) { \
00407                                   tcp_tmp_pcb->next = (npcb)->next; \
00408                                   break; \
00409                                } \
00410                             } \
00411                             (npcb)->next = NULL; \
00412                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00413                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
00414                             } while(0)
00415 
00416 #else /* LWIP_DEBUG */
00417 
00418 #define TCP_REG(pcbs, npcb)                        \
00419   do {                                             \
00420     (npcb)->next = *pcbs;                          \
00421     *(pcbs) = (npcb);                              \
00422     tcp_timer_needed();                            \
00423   } while (0)
00424 
00425 #define TCP_RMV(pcbs, npcb)                        \
00426   do {                                             \
00427     if(*(pcbs) == (npcb)) {                        \
00428       (*(pcbs)) = (*pcbs)->next;                   \
00429     }                                              \
00430     else {                                         \
00431       struct tcp_pcb *tcp_tmp_pcb;                 \
00432       for (tcp_tmp_pcb = *pcbs;                    \
00433           tcp_tmp_pcb != NULL;                     \
00434           tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
00435         if(tcp_tmp_pcb->next == (npcb)) {          \
00436           tcp_tmp_pcb->next = (npcb)->next;        \
00437           break;                                   \
00438         }                                          \
00439       }                                            \
00440     }                                              \
00441     (npcb)->next = NULL;                           \
00442   } while(0)
00443 
00444 #endif /* LWIP_DEBUG */
00445 
00446 #define TCP_REG_ACTIVE(npcb)                       \
00447   do {                                             \
00448     TCP_REG(&tcp_active_pcbs, npcb);               \
00449     tcp_active_pcbs_changed = 1;                   \
00450   } while (0)
00451 
00452 #define TCP_RMV_ACTIVE(npcb)                       \
00453   do {                                             \
00454     TCP_RMV(&tcp_active_pcbs, npcb);               \
00455     tcp_active_pcbs_changed = 1;                   \
00456   } while (0)
00457 
00458 #define TCP_PCB_REMOVE_ACTIVE(pcb)                 \
00459   do {                                             \
00460     tcp_pcb_remove(&tcp_active_pcbs, pcb);         \
00461     tcp_active_pcbs_changed = 1;                   \
00462   } while (0)
00463 
00464 
00465 /* Internal functions: */
00466 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
00467 void tcp_pcb_purge(struct tcp_pcb *pcb);
00468 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
00469 
00470 void tcp_segs_free(struct tcp_seg *seg);
00471 void tcp_seg_free(struct tcp_seg *seg);
00472 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
00473 
00474 #define tcp_ack(pcb)                               \
00475   do {                                             \
00476     if((pcb)->flags & TF_ACK_DELAY) {              \
00477       (pcb)->flags &= ~TF_ACK_DELAY;               \
00478       (pcb)->flags |= TF_ACK_NOW;                  \
00479     }                                              \
00480     else {                                         \
00481       (pcb)->flags |= TF_ACK_DELAY;                \
00482     }                                              \
00483   } while (0)
00484 
00485 #define tcp_ack_now(pcb)                           \
00486   do {                                             \
00487     (pcb)->flags |= TF_ACK_NOW;                    \
00488   } while (0)
00489 
00490 err_t tcp_send_fin(struct tcp_pcb *pcb);
00491 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
00492 
00493 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
00494 
00495 void tcp_rst(u32_t seqno, u32_t ackno,
00496        const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
00497        u16_t local_port, u16_t remote_port);
00498 
00499 u32_t tcp_next_iss(void);
00500 
00501 err_t tcp_keepalive(struct tcp_pcb *pcb);
00502 err_t tcp_zero_window_probe(struct tcp_pcb *pcb);
00503 void  tcp_trigger_input_pcb_close(void);
00504 
00505 #if TCP_CALCULATE_EFF_SEND_MSS
00506 u16_t tcp_eff_send_mss_impl(u16_t sendmss, const ip_addr_t *dest
00507 #if LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING
00508                            , const ip_addr_t *src
00509 #endif /* LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING */
00510                            );
00511 #if LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING
00512 #define tcp_eff_send_mss(sendmss, src, dest) tcp_eff_send_mss_impl(sendmss, dest, src)
00513 #else /* LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING */
00514 #define tcp_eff_send_mss(sendmss, src, dest) tcp_eff_send_mss_impl(sendmss, dest)
00515 #endif /* LWIP_IPV6 || LWIP_IPV4_SRC_ROUTING */
00516 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
00517 
00518 #if LWIP_CALLBACK_API
00519 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
00520 #endif /* LWIP_CALLBACK_API */
00521 
00522 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
00523 void tcp_debug_print(struct tcp_hdr *tcphdr);
00524 void tcp_debug_print_flags(u8_t flags);
00525 void tcp_debug_print_state(enum tcp_state s);
00526 void tcp_debug_print_pcbs(void);
00527 s16_t tcp_pcbs_sane(void);
00528 #else
00529 #  define tcp_debug_print(tcphdr)
00530 #  define tcp_debug_print_flags(flags)
00531 #  define tcp_debug_print_state(s)
00532 #  define tcp_debug_print_pcbs()
00533 #  define tcp_pcbs_sane() 1
00534 #endif /* TCP_DEBUG */
00535 
00536 /** External function (implemented in timers.c), called when TCP detects
00537  * that a timer is needed (i.e. active- or time-wait-pcb found). */
00538 void tcp_timer_needed(void);
00539 
00540 #if LWIP_IPV4
00541 void tcp_netif_ipv4_addr_changed(const ip4_addr_t* old_addr, const ip4_addr_t* new_addr);
00542 #endif /* LWIP_IPV4 */
00543 
00544 #ifdef __cplusplus
00545 }
00546 #endif
00547 
00548 #endif /* LWIP_TCP */
00549 
00550 #endif /* LWIP_HDR_TCP_H */