tcp_impl.h
20.5 KB
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/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Adam Dunkels <adam@sics.se>
*
*/
#ifndef __LWIP_TCP_IMPL_H__
#define __LWIP_TCP_IMPL_H__
#include "lwip/opt.h"
#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
#include "lwip/tcp.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include "lwip/ip.h"
#include "lwip/icmp.h"
#include "lwip/err.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Functions for interfacing with TCP: */
/* Lower layer interface to TCP: */
void tcp_init (void); /* Initialize this module. */
void tcp_tmr (void); /* Must be called every
TCP_TMR_INTERVAL
ms. (Typically 250 ms). */
/* It is also possible to call these two functions at the right
intervals (instead of calling tcp_tmr()). */
void tcp_slowtmr (void);
void tcp_fasttmr (void);
/* Only used by IP to pass a TCP segment to TCP: */
void tcp_input (struct pbuf *p, struct netif *inp);
/* Used within the TCP code only: */
struct tcp_pcb * tcp_alloc (u8_t prio);
void tcp_abandon (struct tcp_pcb *pcb, int reset);
err_t tcp_send_empty_ack(struct tcp_pcb *pcb);
void tcp_rexmit (struct tcp_pcb *pcb);
void tcp_rexmit_rto (struct tcp_pcb *pcb);
void tcp_rexmit_fast (struct tcp_pcb *pcb);
u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
err_t tcp_process_refused_data(struct tcp_pcb *pcb);
/**
* This is the Nagle algorithm: try to combine user data to send as few TCP
* segments as possible. Only send if
* - no previously transmitted data on the connection remains unacknowledged or
* - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
* - the only unsent segment is at least pcb->mss bytes long (or there is more
* than one unsent segment - with lwIP, this can happen although unsent->len < mss)
* - or if we are in fast-retransmit (TF_INFR)
*/
#define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
(((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
((tpcb)->unsent->len >= (tpcb)->mss))) || \
((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \
) ? 1 : 0)
#define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
#define TCP_SEQ_LT(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0)
#define TCP_SEQ_LEQ(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0)
#define TCP_SEQ_GT(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0)
#define TCP_SEQ_GEQ(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0)
/* is b<=a<=c? */
#if 0 /* see bug #10548 */
#define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
#endif
#define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
#define TCP_FIN 0x01U
#define TCP_SYN 0x02U
#define TCP_RST 0x04U
#define TCP_PSH 0x08U
#define TCP_ACK 0x10U
#define TCP_URG 0x20U
#define TCP_ECE 0x40U
#define TCP_CWR 0x80U
#define TCP_FLAGS 0x3fU
/* Length of the TCP header, excluding options. */
#define TCP_HLEN 20
#ifndef TCP_TMR_INTERVAL
#define TCP_TMR_INTERVAL 200 /* ECONAIS: default timer was 250msecs. The TCP timer interval in milliseconds. */
#endif /* TCP_TMR_INTERVAL */
#ifndef TCP_FAST_INTERVAL
#define TCP_FAST_INTERVAL TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
#endif /* TCP_FAST_INTERVAL */
#ifndef TCP_SLOW_INTERVAL
#define TCP_SLOW_INTERVAL (2*TCP_TMR_INTERVAL) /* the coarse grained timeout in milliseconds */
#endif /* TCP_SLOW_INTERVAL */
#define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
#define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
#define TCP_OOSEQ_TIMEOUT 6U /* x RTO */
#ifndef TCP_MSL
#define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
#endif
/* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
#ifndef TCP_KEEPIDLE_DEFAULT
#define TCP_KEEPIDLE_DEFAULT 7200000UL /* Default KEEPALIVE timer in milliseconds */
#endif
#ifndef TCP_KEEPINTVL_DEFAULT
#define TCP_KEEPINTVL_DEFAULT 75000UL /* Default Time between KEEPALIVE probes in milliseconds */
#endif
#ifndef TCP_KEEPCNT_DEFAULT
#define TCP_KEEPCNT_DEFAULT 9U /* Default Counter for KEEPALIVE probes */
#endif
#define TCP_MAXIDLE TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT /* Maximum KEEPALIVE probe time */
/* Fields are (of course) in network byte order.
* Some fields are converted to host byte order in tcp_input().
*/
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct tcp_hdr {
PACK_STRUCT_FIELD(u16_t src);
PACK_STRUCT_FIELD(u16_t dest);
PACK_STRUCT_FIELD(u32_t seqno);
PACK_STRUCT_FIELD(u32_t ackno);
PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
PACK_STRUCT_FIELD(u16_t wnd);
PACK_STRUCT_FIELD(u16_t chksum);
PACK_STRUCT_FIELD(u16_t urgp);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
#define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
#define TCPH_FLAGS(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
#define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
#define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & PP_HTONS((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
#define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags))
#define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
#define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
#define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
/** Flags used on input processing, not on pcb->flags
*/
#define TF_RESET (u8_t)0x08U /* Connection was reset. */
#define TF_CLOSED (u8_t)0x10U /* Connection was sucessfully closed. */
#define TF_GOT_FIN (u8_t)0x20U /* Connection was closed by the remote end. */
#if LWIP_EVENT_API
#define TCP_EVENT_ACCEPT(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
LWIP_EVENT_ACCEPT, NULL, 0, err)
#define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
LWIP_EVENT_SENT, NULL, space, ERR_OK)
#define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
LWIP_EVENT_RECV, (p), 0, (err))
#define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
LWIP_EVENT_RECV, NULL, 0, ERR_OK)
#define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
LWIP_EVENT_CONNECTED, NULL, 0, (err))
#define TCP_EVENT_POLL(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
LWIP_EVENT_POLL, NULL, 0, ERR_OK)
#define TCP_EVENT_ERR(errf,arg,err) lwip_tcp_event((arg), NULL, \
LWIP_EVENT_ERR, NULL, 0, (err))
#else /* LWIP_EVENT_API */
#define TCP_EVENT_ACCEPT(pcb,err,ret) \
do { \
if((pcb)->accept != NULL) \
(ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err)); \
else (ret) = ERR_ARG; \
} while (0)
#define TCP_EVENT_SENT(pcb,space,ret) \
do { \
if((pcb)->sent != NULL) \
(ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space)); \
else (ret) = ERR_OK; \
} while (0)
#define TCP_EVENT_RECV(pcb,p,err,ret) \
do { \
if((pcb)->recv != NULL) { \
(ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
} else { \
(ret) = tcp_recv_null(NULL, (pcb), (p), (err)); \
} \
} while (0)
#define TCP_EVENT_CLOSED(pcb,ret) \
do { \
if(((pcb)->recv != NULL)) { \
(ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
} else { \
(ret) = ERR_OK; \
} \
} while (0)
#define TCP_EVENT_CONNECTED(pcb,err,ret) \
do { \
if((pcb)->connected != NULL) \
(ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
else (ret) = ERR_OK; \
} while (0)
#define TCP_EVENT_POLL(pcb,ret) \
do { \
if((pcb)->poll != NULL) \
(ret) = (pcb)->poll((pcb)->callback_arg,(pcb)); \
else (ret) = ERR_OK; \
} while (0)
#define TCP_EVENT_ERR(errf,arg,err) \
do { \
if((errf) != NULL) \
(errf)((arg),(err)); \
} while (0)
#endif /* LWIP_EVENT_API */
/** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
#if TCP_OVERSIZE && defined(LWIP_DEBUG)
#define TCP_OVERSIZE_DBGCHECK 1
#else
#define TCP_OVERSIZE_DBGCHECK 0
#endif
/** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
#define TCP_CHECKSUM_ON_COPY (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
/* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
struct tcp_seg {
struct tcp_seg *next; /* used when putting segements on a queue */
struct pbuf *p; /* buffer containing data + TCP header */
u16_t len; /* the TCP length of this segment */
#if TCP_OVERSIZE_DBGCHECK
u16_t oversize_left; /* Extra bytes available at the end of the last
pbuf in unsent (used for asserting vs.
tcp_pcb.unsent_oversized only) */
#endif /* TCP_OVERSIZE_DBGCHECK */
#if TCP_CHECKSUM_ON_COPY
u16_t chksum;
u8_t chksum_swapped;
#endif /* TCP_CHECKSUM_ON_COPY */
u8_t flags;
#define TF_SEG_OPTS_MSS (u8_t)0x01U /* Include MSS option. */
#define TF_SEG_OPTS_TS (u8_t)0x02U /* Include timestamp option. */
#define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
checksummed into 'chksum' */
struct tcp_hdr *tcphdr; /* the TCP header */
};
#define LWIP_TCP_OPT_LENGTH(flags) \
(flags & TF_SEG_OPTS_MSS ? 4 : 0) + \
(flags & TF_SEG_OPTS_TS ? 12 : 0)
/** This returns a TCP header option for MSS in an u32_t */
#define TCP_BUILD_MSS_OPTION(mss) htonl(0x02040000 | ((mss) & 0xFFFF))
/* Global variables: */
extern struct tcp_pcb *tcp_input_pcb;
extern u32_t tcp_ticks;
extern u8_t tcp_active_pcbs_changed;
/* The TCP PCB lists. */
union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
struct tcp_pcb_listen *listen_pcbs;
struct tcp_pcb *pcbs;
};
extern struct tcp_pcb *tcp_bound_pcbs;
extern union tcp_listen_pcbs_t tcp_listen_pcbs;
extern struct tcp_pcb *tcp_active_pcbs; /* List of all TCP PCBs that are in a
state in which they accept or send
data. */
extern struct tcp_pcb *tcp_tw_pcbs; /* List of all TCP PCBs in TIME-WAIT. */
extern struct tcp_pcb *tcp_tmp_pcb; /* Only used for temporary storage. */
/* Axioms about the above lists:
1) Every TCP PCB that is not CLOSED is in one of the lists.
2) A PCB is only in one of the lists.
3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
*/
/* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
with a PCB list or removes a PCB from a list, respectively. */
#ifndef TCP_DEBUG_PCB_LISTS
#define TCP_DEBUG_PCB_LISTS 0
#endif
#if TCP_DEBUG_PCB_LISTS
#define TCP_REG(pcbs, npcb) do {\
LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
for(tcp_tmp_pcb = *(pcbs); \
tcp_tmp_pcb != NULL; \
tcp_tmp_pcb = tcp_tmp_pcb->next) { \
LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
} \
LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
(npcb)->next = *(pcbs); \
LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
*(pcbs) = (npcb); \
LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
tcp_timer_needed(); \
} while(0)
#define TCP_RMV(pcbs, npcb) do { \
LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
if(*(pcbs) == (npcb)) { \
*(pcbs) = (*pcbs)->next; \
} else for(tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
if(tcp_tmp_pcb->next == (npcb)) { \
tcp_tmp_pcb->next = (npcb)->next; \
break; \
} \
} \
(npcb)->next = NULL; \
LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
} while(0)
#else /* LWIP_DEBUG */
#define TCP_REG(pcbs, npcb) \
do { \
(npcb)->next = *pcbs; \
*(pcbs) = (npcb); \
tcp_timer_needed(); \
} while (0)
#define TCP_RMV(pcbs, npcb) \
do { \
if(*(pcbs) == (npcb)) { \
(*(pcbs)) = (*pcbs)->next; \
} \
else { \
for(tcp_tmp_pcb = *pcbs; \
tcp_tmp_pcb != NULL; \
tcp_tmp_pcb = tcp_tmp_pcb->next) { \
if(tcp_tmp_pcb->next == (npcb)) { \
tcp_tmp_pcb->next = (npcb)->next; \
break; \
} \
} \
} \
(npcb)->next = NULL; \
} while(0)
#endif /* LWIP_DEBUG */
#define TCP_REG_ACTIVE(npcb) \
do { \
TCP_REG(&tcp_active_pcbs, npcb); \
tcp_active_pcbs_changed = 1; \
} while (0)
#define TCP_RMV_ACTIVE(npcb) \
do { \
TCP_RMV(&tcp_active_pcbs, npcb); \
tcp_active_pcbs_changed = 1; \
} while (0)
#define TCP_PCB_REMOVE_ACTIVE(pcb) \
do { \
tcp_pcb_remove(&tcp_active_pcbs, pcb); \
tcp_active_pcbs_changed = 1; \
} while (0)
/* Internal functions: */
struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
void tcp_pcb_purge(struct tcp_pcb *pcb);
void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
void tcp_segs_free(struct tcp_seg *seg);
void tcp_seg_free(struct tcp_seg *seg);
struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
#define tcp_ack(pcb) \
do { \
if((pcb)->flags & TF_ACK_DELAY) { \
(pcb)->flags &= ~TF_ACK_DELAY; \
(pcb)->flags |= TF_ACK_NOW; \
} \
else { \
(pcb)->flags |= TF_ACK_DELAY; \
} \
} while (0)
#define tcp_ack_now(pcb) \
do { \
(pcb)->flags |= TF_ACK_NOW; \
} while (0)
err_t tcp_send_fin(struct tcp_pcb *pcb);
err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
void tcp_rst(u32_t seqno, u32_t ackno,
ip_addr_t *local_ip, ip_addr_t *remote_ip,
u16_t local_port, u16_t remote_port);
u32_t tcp_next_iss(void);
void tcp_keepalive(struct tcp_pcb *pcb);
void tcp_zero_window_probe(struct tcp_pcb *pcb);
#if TCP_CALCULATE_EFF_SEND_MSS
u16_t tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr);
#endif /* TCP_CALCULATE_EFF_SEND_MSS */
#if LWIP_CALLBACK_API
err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
#endif /* LWIP_CALLBACK_API */
#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
void tcp_debug_print(struct tcp_hdr *tcphdr);
void tcp_debug_print_flags(u8_t flags);
void tcp_debug_print_state(enum tcp_state s);
void tcp_debug_print_pcbs(void);
s16_t tcp_pcbs_sane(void);
#else
# define tcp_debug_print(tcphdr)
# define tcp_debug_print_flags(flags)
# define tcp_debug_print_state(s)
# define tcp_debug_print_pcbs()
# define tcp_pcbs_sane() 1
#endif /* TCP_DEBUG */
/** External function (implemented in timers.c), called when TCP detects
* that a timer is needed (i.e. active- or time-wait-pcb found). */
void tcp_timer_needed(void);
#ifdef __cplusplus
}
#endif
#endif /* LWIP_TCP */
#endif /* __LWIP_TCP_H__ */