2 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
19 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
21 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
24 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
27 * This file is part of the lwIP TCP/IP stack.
29 * Author: Adam Dunkels <adam@sics.se>
32 #ifndef __LWIP_TCP_IMPL_H__
33 #define __LWIP_TCP_IMPL_H__
37 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
41 #include "lwip/pbuf.h"
43 #include "lwip/icmp.h"
46 #include "lwip/ip6_addr.h"
52 /* Functions for interfacing with TCP: */
54 /* Lower layer interface to TCP: */
55 #define tcp_init() /* Compatibility define, no init needed. */
56 void tcp_tmr (void); /* Must be called every
58 ms. (Typically 250 ms). */
59 /* It is also possible to call these two functions at the right
60 intervals (instead of calling tcp_tmr()). */
61 void tcp_slowtmr (void);
62 void tcp_fasttmr (void);
65 /* Only used by IP to pass a TCP segment to TCP: */
66 void tcp_input (struct pbuf *p, struct netif *inp);
67 /* Used within the TCP code only: */
68 struct tcp_pcb * tcp_alloc (u8_t prio);
69 void tcp_abandon (struct tcp_pcb *pcb, int reset);
70 err_t tcp_send_empty_ack(struct tcp_pcb *pcb);
71 void tcp_rexmit (struct tcp_pcb *pcb);
72 void tcp_rexmit_rto (struct tcp_pcb *pcb);
73 void tcp_rexmit_fast (struct tcp_pcb *pcb);
74 u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
77 * This is the Nagle algorithm: try to combine user data to send as few TCP
78 * segments as possible. Only send if
79 * - no previously transmitted data on the connection remains unacknowledged or
80 * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
81 * - the only unsent segment is at least pcb->mss bytes long (or there is more
82 * than one unsent segment - with lwIP, this can happen although unsent->len < mss)
83 * - or if we are in fast-retransmit (TF_INFR)
85 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
86 ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
87 (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
88 ((tpcb)->unsent->len >= (tpcb)->mss))) \
90 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
93 #define TCP_SEQ_LT(a,b) ((s32_t)((a)-(b)) < 0)
94 #define TCP_SEQ_LEQ(a,b) ((s32_t)((a)-(b)) <= 0)
95 #define TCP_SEQ_GT(a,b) ((s32_t)((a)-(b)) > 0)
96 #define TCP_SEQ_GEQ(a,b) ((s32_t)((a)-(b)) >= 0)
98 #if 0 /* see bug #10548 */
99 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
101 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
102 #define TCP_FIN 0x01U
103 #define TCP_SYN 0x02U
104 #define TCP_RST 0x04U
105 #define TCP_PSH 0x08U
106 #define TCP_ACK 0x10U
107 #define TCP_URG 0x20U
108 #define TCP_ECE 0x40U
109 #define TCP_CWR 0x80U
111 #define TCP_FLAGS 0x3fU
113 /* Length of the TCP header, excluding options. */
116 #ifndef TCP_TMR_INTERVAL
117 #define TCP_TMR_INTERVAL 250 /* The TCP timer interval in milliseconds. */
118 #endif /* TCP_TMR_INTERVAL */
120 #ifndef TCP_FAST_INTERVAL
121 #define TCP_FAST_INTERVAL TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
122 #endif /* TCP_FAST_INTERVAL */
124 #ifndef TCP_SLOW_INTERVAL
125 #define TCP_SLOW_INTERVAL (2*TCP_TMR_INTERVAL) /* the coarse grained timeout in milliseconds */
126 #endif /* TCP_SLOW_INTERVAL */
128 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
129 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
131 #define TCP_OOSEQ_TIMEOUT 6U /* x RTO */
134 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
137 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
138 #ifndef TCP_KEEPIDLE_DEFAULT
139 #define TCP_KEEPIDLE_DEFAULT 7200000UL /* Default KEEPALIVE timer in milliseconds */
142 #ifndef TCP_KEEPINTVL_DEFAULT
143 #define TCP_KEEPINTVL_DEFAULT 75000UL /* Default Time between KEEPALIVE probes in milliseconds */
146 #ifndef TCP_KEEPCNT_DEFAULT
147 #define TCP_KEEPCNT_DEFAULT 9U /* Default Counter for KEEPALIVE probes */
150 #define TCP_MAXIDLE TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT /* Maximum KEEPALIVE probe time */
152 /* Fields are (of course) in network byte order.
153 * Some fields are converted to host byte order in tcp_input().
155 #ifdef PACK_STRUCT_USE_INCLUDES
156 # include "arch/bpstruct.h"
160 PACK_STRUCT_FIELD(u16_t src);
161 PACK_STRUCT_FIELD(u16_t dest);
162 PACK_STRUCT_FIELD(u32_t seqno);
163 PACK_STRUCT_FIELD(u32_t ackno);
164 PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
165 PACK_STRUCT_FIELD(u16_t wnd);
166 PACK_STRUCT_FIELD(u16_t chksum);
167 PACK_STRUCT_FIELD(u16_t urgp);
168 } PACK_STRUCT_STRUCT;
170 #ifdef PACK_STRUCT_USE_INCLUDES
171 # include "arch/epstruct.h"
174 #define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
175 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
176 #define TCPH_FLAGS(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
178 #define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
179 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
180 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & PP_HTONS((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
181 #define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags))
183 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
184 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
186 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
188 /** Flags used on input processing, not on pcb->flags
190 #define TF_RESET (u8_t)0x08U /* Connection was reset. */
191 #define TF_CLOSED (u8_t)0x10U /* Connection was sucessfully closed. */
192 #define TF_GOT_FIN (u8_t)0x20U /* Connection was closed by the remote end. */
197 #define TCP_EVENT_ACCEPT(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
198 LWIP_EVENT_ACCEPT, NULL, 0, err)
199 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
200 LWIP_EVENT_SENT, NULL, space, ERR_OK)
201 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
202 LWIP_EVENT_RECV, (p), 0, (err))
203 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
204 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
205 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
206 LWIP_EVENT_CONNECTED, NULL, 0, (err))
207 #define TCP_EVENT_POLL(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
208 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
209 #define TCP_EVENT_ERR(errf,arg,err) lwip_tcp_event((arg), NULL, \
210 LWIP_EVENT_ERR, NULL, 0, (err))
212 #else /* LWIP_EVENT_API */
214 #define TCP_EVENT_ACCEPT(pcb,err,ret) \
216 if((pcb)->accept != NULL) \
217 (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err)); \
218 else (ret) = ERR_ARG; \
221 #define TCP_EVENT_SENT(pcb,space,ret) \
223 if((pcb)->sent != NULL) \
224 (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space)); \
225 else (ret) = ERR_OK; \
228 #define TCP_EVENT_RECV(pcb,p,err,ret) \
230 if((pcb)->recv != NULL) { \
231 (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
233 (ret) = tcp_recv_null(NULL, (pcb), (p), (err)); \
237 #define TCP_EVENT_CLOSED(pcb,ret) \
239 if(((pcb)->recv != NULL)) { \
240 (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
246 #define TCP_EVENT_CONNECTED(pcb,err,ret) \
248 if((pcb)->connected != NULL) \
249 (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
250 else (ret) = ERR_OK; \
253 #define TCP_EVENT_POLL(pcb,ret) \
255 if((pcb)->poll != NULL) \
256 (ret) = (pcb)->poll((pcb)->callback_arg,(pcb)); \
257 else (ret) = ERR_OK; \
260 #define TCP_EVENT_ERR(errf,arg,err) \
263 (errf)((arg),(err)); \
266 #endif /* LWIP_EVENT_API */
268 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
269 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
270 #define TCP_OVERSIZE_DBGCHECK 1
272 #define TCP_OVERSIZE_DBGCHECK 0
275 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
276 #define TCP_CHECKSUM_ON_COPY (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
278 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
280 struct tcp_seg *next; /* used when putting segements on a queue */
281 struct pbuf *p; /* buffer containing data + TCP header */
282 u16_t len; /* the TCP length of this segment */
283 #if TCP_OVERSIZE_DBGCHECK
284 u16_t oversize_left; /* Extra bytes available at the end of the last
285 pbuf in unsent (used for asserting vs.
286 tcp_pcb.unsent_oversized only) */
287 #endif /* TCP_OVERSIZE_DBGCHECK */
288 #if TCP_CHECKSUM_ON_COPY
291 #endif /* TCP_CHECKSUM_ON_COPY */
293 #define TF_SEG_OPTS_MSS (u8_t)0x01U /* Include MSS option. */
294 #define TF_SEG_OPTS_TS (u8_t)0x02U /* Include timestamp option. */
295 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
296 checksummed into 'chksum' */
297 struct tcp_hdr *tcphdr; /* the TCP header */
300 #define LWIP_TCP_OPT_LENGTH(flags) \
301 (flags & TF_SEG_OPTS_MSS ? 4 : 0) + \
302 (flags & TF_SEG_OPTS_TS ? 12 : 0)
304 /** This returns a TCP header option for MSS in an u32_t */
305 #define TCP_BUILD_MSS_OPTION(x) (x) = PP_HTONL(((u32_t)2 << 24) | \
307 (((u32_t)TCP_MSS / 256) << 8) | \
310 /* Global variables: */
311 extern struct tcp_pcb *tcp_input_pcb;
312 extern u32_t tcp_ticks;
314 /* The TCP PCB lists. */
315 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
316 struct tcp_pcb_listen *listen_pcbs;
317 struct tcp_pcb *pcbs;
319 extern struct tcp_pcb *tcp_bound_pcbs;
320 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
321 extern struct tcp_pcb *tcp_active_pcbs; /* List of all TCP PCBs that are in a
322 state in which they accept or send
324 extern struct tcp_pcb *tcp_tw_pcbs; /* List of all TCP PCBs in TIME-WAIT. */
326 extern struct tcp_pcb *tcp_tmp_pcb; /* Only used for temporary storage. */
328 /* Axioms about the above lists:
329 1) Every TCP PCB that is not CLOSED is in one of the lists.
330 2) A PCB is only in one of the lists.
331 3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
332 4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
334 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
335 with a PCB list or removes a PCB from a list, respectively. */
336 #ifndef TCP_DEBUG_PCB_LISTS
337 #define TCP_DEBUG_PCB_LISTS 0
339 #if TCP_DEBUG_PCB_LISTS
340 #define TCP_REG(pcbs, npcb) do {\
341 LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
342 for(tcp_tmp_pcb = *(pcbs); \
343 tcp_tmp_pcb != NULL; \
344 tcp_tmp_pcb = tcp_tmp_pcb->next) { \
345 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
347 LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
348 (npcb)->next = *(pcbs); \
349 LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
351 LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
352 tcp_timer_needed(); \
354 #define TCP_RMV(pcbs, npcb) do { \
355 LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
356 LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
357 if(*(pcbs) == (npcb)) { \
358 *(pcbs) = (*pcbs)->next; \
359 } else for(tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
360 if(tcp_tmp_pcb->next == (npcb)) { \
361 tcp_tmp_pcb->next = (npcb)->next; \
365 (npcb)->next = NULL; \
366 LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
367 LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
370 #else /* LWIP_DEBUG */
372 #define TCP_REG(pcbs, npcb) \
374 (npcb)->next = *pcbs; \
376 tcp_timer_needed(); \
379 #define TCP_RMV(pcbs, npcb) \
381 if(*(pcbs) == (npcb)) { \
382 (*(pcbs)) = (*pcbs)->next; \
385 for(tcp_tmp_pcb = *pcbs; \
386 tcp_tmp_pcb != NULL; \
387 tcp_tmp_pcb = tcp_tmp_pcb->next) { \
388 if(tcp_tmp_pcb->next == (npcb)) { \
389 tcp_tmp_pcb->next = (npcb)->next; \
394 (npcb)->next = NULL; \
397 #endif /* LWIP_DEBUG */
400 /* Internal functions: */
401 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
402 void tcp_pcb_purge(struct tcp_pcb *pcb);
403 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
405 void tcp_segs_free(struct tcp_seg *seg);
406 void tcp_seg_free(struct tcp_seg *seg);
407 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
409 #define tcp_ack(pcb) \
411 if((pcb)->flags & TF_ACK_DELAY) { \
412 (pcb)->flags &= ~TF_ACK_DELAY; \
413 (pcb)->flags |= TF_ACK_NOW; \
416 (pcb)->flags |= TF_ACK_DELAY; \
420 #define tcp_ack_now(pcb) \
422 (pcb)->flags |= TF_ACK_NOW; \
425 err_t tcp_send_fin(struct tcp_pcb *pcb);
426 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
428 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
430 void tcp_rst_impl(u32_t seqno, u32_t ackno,
431 ipX_addr_t *local_ip, ipX_addr_t *remote_ip,
432 u16_t local_port, u16_t remote_port
435 #endif /* LWIP_IPV6 */
438 #define tcp_rst(seqno, ackno, local_ip, remote_ip, local_port, remote_port, isipv6) \
439 tcp_rst_impl(seqno, ackno, local_ip, remote_ip, local_port, remote_port, isipv6)
440 #else /* LWIP_IPV6 */
441 #define tcp_rst(seqno, ackno, local_ip, remote_ip, local_port, remote_port, isipv6) \
442 tcp_rst_impl(seqno, ackno, local_ip, remote_ip, local_port, remote_port)
443 #endif /* LWIP_IPV6 */
445 u32_t tcp_next_iss(void);
447 void tcp_keepalive(struct tcp_pcb *pcb);
448 void tcp_zero_window_probe(struct tcp_pcb *pcb);
450 #if TCP_CALCULATE_EFF_SEND_MSS
451 u16_t tcp_eff_send_mss_impl(u16_t sendmss, ipX_addr_t *dest
453 , ipX_addr_t *src, u8_t isipv6
454 #endif /* LWIP_IPV6 */
457 #define tcp_eff_send_mss(sendmss, src, dest, isipv6) tcp_eff_send_mss_impl(sendmss, dest, src, isipv6)
458 #else /* LWIP_IPV6 */
459 #define tcp_eff_send_mss(sendmss, src, dest, isipv6) tcp_eff_send_mss_impl(sendmss, dest)
460 #endif /* LWIP_IPV6 */
461 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
463 #if LWIP_CALLBACK_API
464 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
465 #endif /* LWIP_CALLBACK_API */
467 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
468 void tcp_debug_print(struct tcp_hdr *tcphdr);
469 void tcp_debug_print_flags(u8_t flags);
470 void tcp_debug_print_state(enum tcp_state s);
471 void tcp_debug_print_pcbs(void);
472 s16_t tcp_pcbs_sane(void);
474 # define tcp_debug_print(tcphdr)
475 # define tcp_debug_print_flags(flags)
476 # define tcp_debug_print_state(s)
477 # define tcp_debug_print_pcbs()
478 # define tcp_pcbs_sane() 1
479 #endif /* TCP_DEBUG */
481 /** External function (implemented in timers.c), called when TCP detects
482 * that a timer is needed (i.e. active- or time-wait-pcb found). */
483 void tcp_timer_needed(void);
490 #endif /* LWIP_TCP */
492 #endif /* __LWIP_TCP_H__ */