tcp_impl.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_IMPL_H__
00033 #define __LWIP_TCP_IMPL_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/tcp.h"
00040 #include "lwip/sys.h"
00041 #include "lwip/mem.h"
00042 #include "lwip/pbuf.h"
00043 #include "lwip/ip.h"
00044 #include "lwip/icmp.h"
00045 #include "lwip/err.h"
00046 
00047 #ifdef __cplusplus
00048 extern "C" {
00049 #endif
00050 
00051 /* Functions for interfacing with TCP: */
00052 
00053 /* Lower layer interface to TCP: */
00054 #define tcp_init() /* Compatibility define, no init needed. */
00055 void             tcp_tmr     (void);  /* Must be called every
00056                                          TCP_TMR_INTERVAL
00057                                          ms. (Typically 250 ms). */
00058 /* It is also possible to call these two functions at the right
00059    intervals (instead of calling tcp_tmr()). */
00060 void             tcp_slowtmr (void);
00061 void             tcp_fasttmr (void);
00062 
00063 
00064 /* Only used by IP to pass a TCP segment to TCP: */
00065 void             tcp_input   (struct pbuf *p, struct netif *inp);
00066 /* Used within the TCP code only: */
00067 struct tcp_pcb * tcp_alloc   (u8_t prio);
00068 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
00069 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
00070 void             tcp_rexmit  (struct tcp_pcb *pcb);
00071 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
00072 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
00073 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
00074 
00075 /**
00076  * This is the Nagle algorithm: try to combine user data to send as few TCP
00077  * segments as possible. Only send if
00078  * - no previously transmitted data on the connection remains unacknowledged or
00079  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
00080  * - the only unsent segment is at least pcb->mss bytes long (or there is more
00081  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
00082  * - or if we are in fast-retransmit (TF_INFR)
00083  */
00084 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
00085                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
00086                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
00087                               ((tpcb)->unsent->len >= (tpcb)->mss))) \
00088                             ) ? 1 : 0)
00089 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
00090 
00091 
00092 #define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)
00093 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)
00094 #define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)
00095 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)
00096 /* is b<=a<=c? */
00097 #if 0 /* see bug #10548 */
00098 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
00099 #endif
00100 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
00101 #define TCP_FIN 0x01U
00102 #define TCP_SYN 0x02U
00103 #define TCP_RST 0x04U
00104 #define TCP_PSH 0x08U
00105 #define TCP_ACK 0x10U
00106 #define TCP_URG 0x20U
00107 #define TCP_ECE 0x40U
00108 #define TCP_CWR 0x80U
00109 
00110 #define TCP_FLAGS 0x3fU
00111 
00112 /* Length of the TCP header, excluding options. */
00113 #define TCP_HLEN 20
00114 
00115 #ifndef TCP_TMR_INTERVAL
00116 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
00117 #endif /* TCP_TMR_INTERVAL */
00118 
00119 #ifndef TCP_FAST_INTERVAL
00120 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
00121 #endif /* TCP_FAST_INTERVAL */
00122 
00123 #ifndef TCP_SLOW_INTERVAL
00124 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
00125 #endif /* TCP_SLOW_INTERVAL */
00126 
00127 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
00128 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
00129 
00130 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
00131 
00132 #ifndef TCP_MSL
00133 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
00134 #endif
00135 
00136 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
00137 #ifndef  TCP_KEEPIDLE_DEFAULT
00138 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
00139 #endif
00140 
00141 #ifndef  TCP_KEEPINTVL_DEFAULT
00142 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
00143 #endif
00144 
00145 #ifndef  TCP_KEEPCNT_DEFAULT
00146 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
00147 #endif
00148 
00149 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
00150 
00151 /* Fields are (of course) in network byte order.
00152  * Some fields are converted to host byte order in tcp_input().
00153  */
00154 #ifdef PACK_STRUCT_USE_INCLUDES
00155 #  include "arch/bpstruct.h"
00156 #endif
00157 PACK_STRUCT_BEGIN
00158 struct tcp_hdr {
00159   PACK_STRUCT_FIELD(u16_t src);
00160   PACK_STRUCT_FIELD(u16_t dest);
00161   PACK_STRUCT_FIELD(u32_t seqno);
00162   PACK_STRUCT_FIELD(u32_t ackno);
00163   PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
00164   PACK_STRUCT_FIELD(u16_t wnd);
00165   PACK_STRUCT_FIELD(u16_t chksum);
00166   PACK_STRUCT_FIELD(u16_t urgp);
00167 } PACK_STRUCT_STRUCT;
00168 PACK_STRUCT_END
00169 #ifdef PACK_STRUCT_USE_INCLUDES
00170 #  include "arch/epstruct.h"
00171 #endif
00172 
00173 #define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
00174 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
00175 #define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
00176 
00177 #define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
00178 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
00179 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & htons((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
00180 #define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags))
00181 
00182 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
00183 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
00184 
00185 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
00186 
00187 /** Flags used on input processing, not on pcb->flags
00188 */
00189 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
00190 #define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */
00191 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
00192 
00193 
00194 #if LWIP_EVENT_API
00195 
00196 #define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00197                 LWIP_EVENT_ACCEPT, NULL, 0, err)
00198 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00199                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
00200 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00201                 LWIP_EVENT_RECV, (p), 0, (err))
00202 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00203                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
00204 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
00205                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
00206 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
00207                 LWIP_EVENT_ERR, NULL, 0, (err))
00208 
00209 #else /* LWIP_EVENT_API */
00210 
00211 #define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
00212   do {                                                         \
00213     if((pcb)->accept != NULL)                                  \
00214       (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
00215     else (ret) = ERR_ARG;                                      \
00216   } while (0)
00217 
00218 #define TCP_EVENT_SENT(pcb,space,ret)                          \
00219   do {                                                         \
00220     if((pcb)->sent != NULL)                                    \
00221       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
00222     else (ret) = ERR_OK;                                       \
00223   } while (0)
00224 
00225 #define TCP_EVENT_RECV(pcb,p,err,ret)                              \
00226   do {                                                             \
00227     if(((pcb)->recv != NULL) && (!((pcb)->flags & TF_RXCLOSED))) { \
00228       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));    \
00229     } else {                                                       \
00230       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));              \
00231     }                                                              \
00232   } while (0)
00233 
00234 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
00235   do {                                                           \
00236     if((pcb)->connected != NULL)                                 \
00237       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
00238     else (ret) = ERR_OK;                                         \
00239   } while (0)
00240 
00241 #define TCP_EVENT_POLL(pcb,ret)                                \
00242   do {                                                         \
00243     if((pcb)->poll != NULL)                                    \
00244       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
00245     else (ret) = ERR_OK;                                       \
00246   } while (0)
00247 
00248 #define TCP_EVENT_ERR(errf,arg,err)                            \
00249   do {                                                         \
00250     if((errf) != NULL)                                         \
00251       (errf)((arg),(err));                                     \
00252   } while (0)
00253 
00254 #endif /* LWIP_EVENT_API */
00255 
00256 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
00257 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
00258 #define TCP_OVERSIZE_DBGCHECK 1
00259 #else
00260 #define TCP_OVERSIZE_DBGCHECK 0
00261 #endif
00262 
00263 /** Don't generate chceksum on copy if CHECKSUM_GEN_TCP is disabled */
00264 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
00265 
00266 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
00267 struct tcp_seg {
00268   struct tcp_seg *next;    /* used when putting segements on a queue */
00269   struct pbuf *p;          /* buffer containing data + TCP header */
00270   void *dataptr;           /* pointer to the TCP data in the pbuf */
00271   u16_t len;               /* the TCP length of this segment */
00272 #if TCP_OVERSIZE_DBGCHECK
00273   u16_t oversize_left;     /* Extra bytes available at the end of the last
00274                               pbuf in unsent (used for asserting vs.
00275                               tcp_pcb.unsent_oversized only) */
00276 #endif /* TCP_OVERSIZE_DBGCHECK */ 
00277 #if TCP_CHECKSUM_ON_COPY
00278   u16_t chksum;
00279   u8_t  chksum_swapped;
00280 #endif /* TCP_CHECKSUM_ON_COPY */
00281   u8_t  flags;
00282 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option. */
00283 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
00284 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
00285                                                checksummed into 'chksum' */
00286   struct tcp_hdr *tcphdr;  /* the TCP header */
00287 };
00288 
00289 #define LWIP_TCP_OPT_LENGTH(flags)              \
00290   (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
00291   (flags & TF_SEG_OPTS_TS  ? 12 : 0)
00292 
00293 /** This returns a TCP header option for MSS in an u32_t */
00294 #define TCP_BUILD_MSS_OPTION(x) (x) = htonl(((u32_t)2 << 24) |          \
00295                                             ((u32_t)4 << 16) |          \
00296                                             (((u32_t)TCP_MSS / 256) << 8) | \
00297                                             (TCP_MSS & 255))
00298 
00299 /* Global variables: */
00300 extern struct tcp_pcb *tcp_input_pcb;
00301 extern u32_t tcp_ticks;
00302 
00303 /* The TCP PCB lists. */
00304 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
00305   struct tcp_pcb_listen *listen_pcbs; 
00306   struct tcp_pcb *pcbs;
00307 };
00308 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
00309 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
00310               state in which they accept or send
00311               data. */
00312 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
00313 
00314 extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */
00315 
00316 /* Axioms about the above lists:   
00317    1) Every TCP PCB that is not CLOSED is in one of the lists.
00318    2) A PCB is only in one of the lists.
00319    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
00320    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
00321 */
00322 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
00323    with a PCB list or removes a PCB from a list, respectively. */
00324 #if 0
00325 #define TCP_REG(pcbs, npcb) do {\
00326                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \
00327                             for(tcp_tmp_pcb = *pcbs; \
00328           tcp_tmp_pcb != NULL; \
00329         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00330                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
00331                             } \
00332                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
00333                             npcb->next = *pcbs; \
00334                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
00335                             *(pcbs) = npcb; \
00336                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00337               tcp_timer_needed(); \
00338                             } while(0)
00339 #define TCP_RMV(pcbs, npcb) do { \
00340                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
00341                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \
00342                             if(*pcbs == npcb) { \
00343                                *pcbs = (*pcbs)->next; \
00344                             } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00345                                if(tcp_tmp_pcb->next == npcb) { \
00346                                   tcp_tmp_pcb->next = npcb->next; \
00347                                   break; \
00348                                } \
00349                             } \
00350                             npcb->next = NULL; \
00351                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00352                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \
00353                             } while(0)
00354 
00355 #else /* LWIP_DEBUG */
00356 
00357 #define TCP_REG(pcbs, npcb)                        \
00358   do {                                             \
00359     npcb->next = *pcbs;                            \
00360     *(pcbs) = npcb;                                \
00361     tcp_timer_needed();                            \
00362   } while (0)
00363 
00364 #define TCP_RMV(pcbs, npcb)                        \
00365   do {                                             \
00366     if(*(pcbs) == npcb) {                          \
00367       (*(pcbs)) = (*pcbs)->next;                   \
00368     }                                              \
00369     else {                                         \
00370       for(tcp_tmp_pcb = *pcbs;                                         \
00371           tcp_tmp_pcb != NULL;                                         \
00372           tcp_tmp_pcb = tcp_tmp_pcb->next) {                           \
00373         if(tcp_tmp_pcb->next == npcb) {   \
00374           tcp_tmp_pcb->next = npcb->next;          \
00375           break;                                   \
00376         }                                          \
00377       }                                            \
00378     }                                              \
00379     npcb->next = NULL;                             \
00380   } while(0)
00381 
00382 #endif /* LWIP_DEBUG */
00383 
00384 
00385 /* Internal functions: */
00386 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
00387 void tcp_pcb_purge(struct tcp_pcb *pcb);
00388 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
00389 
00390 void tcp_segs_free(struct tcp_seg *seg);
00391 void tcp_seg_free(struct tcp_seg *seg);
00392 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
00393 
00394 #define tcp_ack(pcb)                               \
00395   do {                                             \
00396     if((pcb)->flags & TF_ACK_DELAY) {              \
00397       (pcb)->flags &= ~TF_ACK_DELAY;               \
00398       (pcb)->flags |= TF_ACK_NOW;                  \
00399     }                                              \
00400     else {                                         \
00401       (pcb)->flags |= TF_ACK_DELAY;                \
00402     }                                              \
00403   } while (0)
00404 
00405 #define tcp_ack_now(pcb)                           \
00406   do {                                             \
00407     (pcb)->flags |= TF_ACK_NOW;                    \
00408   } while (0)
00409 
00410 err_t tcp_send_fin(struct tcp_pcb *pcb);
00411 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
00412 
00413 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
00414 
00415 void tcp_rst(u32_t seqno, u32_t ackno,
00416        ip_addr_t *local_ip, ip_addr_t *remote_ip,
00417        u16_t local_port, u16_t remote_port);
00418 
00419 u32_t tcp_next_iss(void);
00420 
00421 void tcp_keepalive(struct tcp_pcb *pcb);
00422 void tcp_zero_window_probe(struct tcp_pcb *pcb);
00423 
00424 #if TCP_CALCULATE_EFF_SEND_MSS
00425 u16_t tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr);
00426 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
00427 
00428 #if LWIP_CALLBACK_API
00429 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
00430 #endif /* LWIP_CALLBACK_API */
00431 
00432 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
00433 void tcp_debug_print(struct tcp_hdr *tcphdr);
00434 void tcp_debug_print_flags(u8_t flags);
00435 void tcp_debug_print_state(enum tcp_state s);
00436 void tcp_debug_print_pcbs(void);
00437 s16_t tcp_pcbs_sane(void);
00438 #else
00439 #  define tcp_debug_print(tcphdr)
00440 #  define tcp_debug_print_flags(flags)
00441 #  define tcp_debug_print_state(s)
00442 #  define tcp_debug_print_pcbs()
00443 #  define tcp_pcbs_sane() 1
00444 #endif /* TCP_DEBUG */
00445 
00446 /** External function (implemented in timers.c), called when TCP detects
00447  * that a timer is needed (i.e. active- or time-wait-pcb found). */
00448 void tcp_timer_needed(void);
00449 
00450 
00451 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
00452    with a PCB list or removes a PCB from a list, respectively. */
00453 #if 0
00454 #define TCP_REG(pcbs, npcb) do {\
00455                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \
00456                             for(tcp_tmp_pcb = *pcbs; \
00457           tcp_tmp_pcb != NULL; \
00458         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00459                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
00460                             } \
00461                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
00462                             npcb->next = *pcbs; \
00463                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
00464                             *(pcbs) = npcb; \
00465                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00466               tcp_timer_needed(); \
00467                             } while(0)
00468 #define TCP_RMV(pcbs, npcb) do { \
00469                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
00470                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \
00471                             if(*pcbs == npcb) { \
00472                                *pcbs = (*pcbs)->next; \
00473                             } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
00474                                if(tcp_tmp_pcb->next == npcb) { \
00475                                   tcp_tmp_pcb->next = npcb->next; \
00476                                   break; \
00477                                } \
00478                             } \
00479                             npcb->next = NULL; \
00480                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
00481                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \
00482                             } while(0)
00483 
00484 #else /* LWIP_DEBUG */
00485 
00486 #define TCP_REG(pcbs, npcb)                        \
00487   do {                                             \
00488     npcb->next = *pcbs;                            \
00489     *(pcbs) = npcb;                                \
00490     tcp_timer_needed();                            \
00491   } while (0)
00492 
00493 #define TCP_RMV(pcbs, npcb)                        \
00494   do {                                             \
00495     if(*(pcbs) == npcb) {                          \
00496       (*(pcbs)) = (*pcbs)->next;                   \
00497     }                                              \
00498     else {                                         \
00499       for(tcp_tmp_pcb = *pcbs;                                         \
00500           tcp_tmp_pcb != NULL;                                         \
00501           tcp_tmp_pcb = tcp_tmp_pcb->next) {                           \
00502         if(tcp_tmp_pcb->next == npcb) {   \
00503           tcp_tmp_pcb->next = npcb->next;          \
00504           break;                                   \
00505         }                                          \
00506       }                                            \
00507     }                                              \
00508     npcb->next = NULL;                             \
00509   } while(0)
00510 
00511 #endif /* LWIP_DEBUG */
00512 
00513 #ifdef __cplusplus
00514 }
00515 #endif
00516 
00517 #endif /* LWIP_TCP */
00518 
00519 #endif /* __LWIP_TCP_H__ */