/** * @file * TCP internal implementations (do not use in application code) */ /* * 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 * */ #ifndef LWIP_HDR_TCP_PRIV_H #define LWIP_HDR_TCP_PRIV_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" #include "lwip/ip6.h" #include "lwip/ip6_addr.h" #include "lwip/prot/tcp.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); /* Call this from a netif driver (watch out for threading issues!) that has returned a memory error on transmit and now has free buffers to send more. This iterates all active pcbs that had an error and tries to call tcp_output, so use this with care as it might slow down the system. */ void tcp_txnow (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_free (struct tcp_pcb *pcb); void tcp_abandon (struct tcp_pcb *pcb, int reset); err_t tcp_send_empty_ack(struct tcp_pcb *pcb); err_t tcp_rexmit (struct tcp_pcb *pcb); err_t tcp_rexmit_rto_prepare(struct tcp_pcb *pcb); void tcp_rexmit_rto_commit(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) (((u32_t)((u32_t)(a) - (u32_t)(b)) & 0x80000000u) != 0) #define TCP_SEQ_LEQ(a,b) (!(TCP_SEQ_LT(b,a))) #define TCP_SEQ_GT(a,b) TCP_SEQ_LT(b,a) #define TCP_SEQ_GEQ(a,b) TCP_SEQ_LEQ(b,a) /* is b<=a<=c? */ #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c)) #ifndef TCP_TMR_INTERVAL #define TCP_TMR_INTERVAL 250 /* 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 */ #define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U)) /** 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 successfully closed. */ #define TF_GOT_FIN (u8_t)0x20U /* Connection was closed by the remote end. */ #if LWIP_EVENT_API #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) ret = lwip_tcp_event(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) do { if ((pcb)->state != SYN_RCVD) { \ ret = lwip_tcp_event((pcb)->callback_arg, (pcb), LWIP_EVENT_POLL, NULL, 0, ERR_OK); \ } else { \ ret = ERR_ARG; } } while(0) /* For event API, last state SYN_RCVD must be excluded here: the application has not seen this pcb, yet! */ #define TCP_EVENT_ERR(last_state,errf,arg,err) do { if (last_state != SYN_RCVD) { \ lwip_tcp_event((arg), NULL, LWIP_EVENT_ERR, NULL, 0, (err)); } } while(0) #else /* LWIP_EVENT_API */ #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) \ do { \ if((lpcb)->accept != NULL) \ (ret) = (lpcb)->accept((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(last_state,errf,arg,err) \ do { \ LWIP_UNUSED_ARG(last_state); \ 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 segments 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_oversize 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 (only used in SYN segments) */ #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' */ #define TF_SEG_OPTS_WND_SCALE (u8_t)0x08U /* Include WND SCALE option (only used in SYN segments) */ #define TF_SEG_OPTS_SACK_PERM (u8_t)0x10U /* Include SACK Permitted option (only used in SYN segments) */ struct tcp_hdr *tcphdr; /* the TCP header */ }; #define LWIP_TCP_OPT_EOL 0 #define LWIP_TCP_OPT_NOP 1 #define LWIP_TCP_OPT_MSS 2 #define LWIP_TCP_OPT_WS 3 #define LWIP_TCP_OPT_SACK_PERM 4 #define LWIP_TCP_OPT_TS 8 #define LWIP_TCP_OPT_LEN_MSS 4 #if LWIP_TCP_TIMESTAMPS #define LWIP_TCP_OPT_LEN_TS 10 #define LWIP_TCP_OPT_LEN_TS_OUT 12 /* aligned for output (includes NOP padding) */ #else #define LWIP_TCP_OPT_LEN_TS_OUT 0 #endif #if LWIP_WND_SCALE #define LWIP_TCP_OPT_LEN_WS 3 #define LWIP_TCP_OPT_LEN_WS_OUT 4 /* aligned for output (includes NOP padding) */ #else #define LWIP_TCP_OPT_LEN_WS_OUT 0 #endif #if LWIP_TCP_SACK_OUT #define LWIP_TCP_OPT_LEN_SACK_PERM 2 #define LWIP_TCP_OPT_LEN_SACK_PERM_OUT 4 /* aligned for output (includes NOP padding) */ #else #define LWIP_TCP_OPT_LEN_SACK_PERM_OUT 0 #endif #define LWIP_TCP_OPT_LENGTH(flags) \ ((flags) & TF_SEG_OPTS_MSS ? LWIP_TCP_OPT_LEN_MSS : 0) + \ ((flags) & TF_SEG_OPTS_TS ? LWIP_TCP_OPT_LEN_TS_OUT : 0) + \ ((flags) & TF_SEG_OPTS_WND_SCALE ? LWIP_TCP_OPT_LEN_WS_OUT : 0) + \ ((flags) & TF_SEG_OPTS_SACK_PERM ? LWIP_TCP_OPT_LEN_SACK_PERM_OUT : 0) /** This returns a TCP header option for MSS in an u32_t */ #define TCP_BUILD_MSS_OPTION(mss) lwip_htonl(0x02040000 | ((mss) & 0xFFFF)) #if LWIP_WND_SCALE #define TCPWNDSIZE_F U32_F #define TCPWND_MAX 0xFFFFFFFFU #define TCPWND_CHECK16(x) LWIP_ASSERT("window size > 0xFFFF", (x) <= 0xFFFF) #define TCPWND_MIN16(x) ((u16_t)LWIP_MIN((x), 0xFFFF)) #else /* LWIP_WND_SCALE */ #define TCPWNDSIZE_F U16_F #define TCPWND_MAX 0xFFFFU #define TCPWND_CHECK16(x) #define TCPWND_MIN16(x) x #endif /* LWIP_WND_SCALE */ /* 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. */ #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT 3 #define NUM_TCP_PCB_LISTS 4 extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS]; /* 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 {\ struct tcp_pcb *tcp_tmp_pcb; \ LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %"U16_F"\n", (void *)(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", 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_REG: tcp_pcbs sane", tcp_pcbs_sane()); \ tcp_timer_needed(); \ } while(0) #define TCP_RMV(pcbs, npcb) do { \ struct tcp_pcb *tcp_tmp_pcb; \ LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \ LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (void *)(npcb), (void *)(*(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", (void *)(npcb), (void *)(*(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 { \ struct tcp_pcb *tcp_tmp_pcb; \ 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) { \ tcp_clear_flags(pcb, TF_ACK_DELAY); \ tcp_ack_now(pcb); \ } \ else { \ tcp_set_flags(pcb, TF_ACK_DELAY); \ } \ } while (0) #define tcp_ack_now(pcb) \ tcp_set_flags(pcb, TF_ACK_NOW) 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(const struct tcp_pcb* pcb, u32_t seqno, u32_t ackno, const ip_addr_t *local_ip, const ip_addr_t *remote_ip, u16_t local_port, u16_t remote_port); void tcp_rst_netif(struct netif *netif, u32_t seqno, u32_t ackno, const ip_addr_t *local_ip, const ip_addr_t *remote_ip, u16_t local_port, u16_t remote_port); u32_t tcp_next_iss(struct tcp_pcb *pcb); err_t tcp_keepalive(struct tcp_pcb *pcb); err_t tcp_split_unsent_seg(struct tcp_pcb *pcb, u16_t split); err_t tcp_zero_window_probe(struct tcp_pcb *pcb); void tcp_trigger_input_pcb_close(void); #if TCP_CALCULATE_EFF_SEND_MSS u16_t tcp_eff_send_mss_netif(u16_t sendmss, struct netif *outif, const ip_addr_t *dest); #define tcp_eff_send_mss(sendmss, src, dest) \ tcp_eff_send_mss_netif(sendmss, ip_route(src, dest), dest) #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); void tcp_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr); #if TCP_QUEUE_OOSEQ void tcp_free_ooseq(struct tcp_pcb *pcb); #endif #if LWIP_TCP_PCB_NUM_EXT_ARGS err_t tcp_ext_arg_invoke_callbacks_passive_open(struct tcp_pcb_listen *lpcb, struct tcp_pcb *cpcb); #endif #ifdef __cplusplus } #endif #endif /* LWIP_TCP */ #endif /* LWIP_HDR_TCP_PRIV_H */