/** * @file * Transmission Control Protocol for IP * * This file contains common functions for the TCP implementation, such as functinos * for manipulating the data structures and the TCP timer functions. TCP functions * related to input and output is found in tcp_in.c and tcp_out.c respectively. * */ /* * 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 * */ #include "vma/lwip/opt.h" #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */ #include "vma/lwip/cc.h" #include "vma/lwip/tcp.h" #include "vma/lwip/tcp_impl.h" #include "vma/lwip/stats.h" #include #include #include #if LWIP_3RD_PARTY_BUFS tcp_tx_pbuf_alloc_fn external_tcp_tx_pbuf_alloc; void register_tcp_tx_pbuf_alloc(tcp_tx_pbuf_alloc_fn fn) { external_tcp_tx_pbuf_alloc = fn; } tcp_tx_pbuf_free_fn external_tcp_tx_pbuf_free; void register_tcp_tx_pbuf_free(tcp_tx_pbuf_free_fn fn) { external_tcp_tx_pbuf_free = fn; } tcp_seg_alloc_fn external_tcp_seg_alloc; void register_tcp_seg_alloc(tcp_seg_alloc_fn fn) { external_tcp_seg_alloc = fn; } tcp_seg_free_fn external_tcp_seg_free; void register_tcp_seg_free(tcp_seg_free_fn fn) { external_tcp_seg_free = fn; } #endif /* allow user to be notified upon tcp_state changes */ tcp_state_observer_fn external_tcp_state_observer; void register_tcp_state_observer(tcp_state_observer_fn fn) { external_tcp_state_observer = fn; } enum cc_algo_mod lwip_cc_algo_module = CC_MOD_LWIP; u16_t lwip_tcp_mss = CONST_TCP_MSS; u8_t enable_ts_option = 0; /* slow timer value */ static u32_t slow_tmr_interval; /* Incremented every coarse grained timer shot (typically every slow_tmr_interval ms). */ u32_t tcp_ticks = 0; const u8_t tcp_backoff[13] = { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7}; /* Times per slowtmr hits */ const u8_t tcp_persist_backoff[7] = { 3, 6, 12, 24, 48, 96, 120 }; /** Only used for temporary storage. */ struct tcp_pcb *tcp_tmp_pcb; /** * * @param v value to set */ void set_tmr_resolution(u32_t v) { slow_tmr_interval = v * 2; } /** * Called periodically to dispatch TCP timers. * */ void tcp_tmr(struct tcp_pcb* pcb) { /* Call tcp_fasttmr() every (slow_tmr_interval / 2) ms */ tcp_fasttmr(pcb); if (++(pcb->tcp_timer) & 1) { /* Call tcp_tmr() every slow_tmr_interval ms, i.e., every other timer tcp_tmr() is called. */ tcp_slowtmr(pcb); } } /** * Closes the TX side of a connection held by the PCB. * For tcp_close(), a RST is sent if the application didn't receive all data * (tcp_recved() not called for all data passed to recv callback). * * Listening pcbs are freed and may not be referenced any more. * Connection pcbs are freed if not yet connected and may not be referenced * any more. If a connection is established (at least SYN received or in * a closing state), the connection is closed, and put in a closing state. * The pcb is then automatically freed in tcp_slowtmr(). It is therefore * unsafe to reference it. * * @param pcb the tcp_pcb to close * @return ERR_OK if connection has been closed * another err_t if closing failed and pcb is not freed */ static err_t tcp_close_shutdown(struct tcp_pcb *pcb, u8_t rst_on_unacked_data) { err_t err; if (rst_on_unacked_data && ((get_tcp_state(pcb) == ESTABLISHED) || (get_tcp_state(pcb) == CLOSE_WAIT))) { if ((pcb->refused_data != NULL) || (pcb->rcv_wnd != pcb->rcv_wnd_max)) { /* Not all data received by application, send RST to tell the remote side about this. */ LWIP_ASSERT("pcb->flags & TF_RXCLOSED", pcb->flags & TF_RXCLOSED); /* don't call tcp_abort here: we must not deallocate the pcb since that might not be expected when calling tcp_close */ tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, pcb->local_port, pcb->remote_port, pcb); tcp_pcb_purge(pcb); if (get_tcp_state(pcb) == ESTABLISHED) { /* move to TIME_WAIT since we close actively */ set_tcp_state(pcb, TIME_WAIT); } else { /* CLOSE_WAIT: deallocate the pcb since we already sent a RST for it */ } return ERR_OK; } } switch (get_tcp_state(pcb)) { case CLOSED: /* Closing a pcb in the CLOSED state might seem erroneous, * however, it is in this state once allocated and as yet unused * and the user needs some way to free it should the need arise. * Calling tcp_close() with a pcb that has already been closed, (i.e. twice) * or for a pcb that has been used and then entered the CLOSED state * is erroneous, but this should never happen as the pcb has in those cases * been freed, and so any remaining handles are bogus. */ err = ERR_OK; pcb = NULL; break; case LISTEN: err = ERR_OK; tcp_pcb_remove(pcb); pcb = NULL; break; case SYN_SENT: err = ERR_OK; tcp_pcb_remove(pcb); pcb = NULL; break; case SYN_RCVD: err = tcp_send_fin(pcb); if (err == ERR_OK) { set_tcp_state(pcb, FIN_WAIT_1); } break; case ESTABLISHED: err = tcp_send_fin(pcb); if (err == ERR_OK) { set_tcp_state(pcb, FIN_WAIT_1); } break; case CLOSE_WAIT: err = tcp_send_fin(pcb); if (err == ERR_OK) { set_tcp_state(pcb, LAST_ACK); } break; default: /* Has already been closed, do nothing. */ err = ERR_OK; pcb = NULL; break; } if (pcb != NULL && err == ERR_OK) { /* To ensure all data has been sent when tcp_close returns, we have to make sure tcp_output doesn't fail. Since we don't really have to ensure all data has been sent when tcp_close returns (unsent data is sent from tcp timer functions, also), we don't care for the return value of tcp_output for now. */ /* @todo: When implementing SO_LINGER, this must be changed somehow: If SOF_LINGER is set, the data should be sent and acked before close returns. This can only be valid for sequential APIs, not for the raw API. */ tcp_output(pcb); } return err; } /** * Closes the connection held by the PCB. * * Listening pcbs are freed and may not be referenced any more. * Connection pcbs are freed if not yet connected and may not be referenced * any more. If a connection is established (at least SYN received or in * a closing state), the connection is closed, and put in a closing state. * The pcb is then automatically freed in tcp_slowtmr(). It is therefore * unsafe to reference it (unless an error is returned). * * @param pcb the tcp_pcb to close * @return ERR_OK if connection has been closed * another err_t if closing failed and pcb is not freed */ err_t tcp_close(struct tcp_pcb *pcb) { #if TCP_DEBUG LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in ")); tcp_debug_print_state(get_tcp_state(pcb)); #endif /* TCP_DEBUG */ if (get_tcp_state(pcb) != LISTEN) { /* Set a flag not to receive any more data... */ pcb->flags |= TF_RXCLOSED; } /* ... and close */ return tcp_close_shutdown(pcb, 1); } /** * Causes all or part of a full-duplex connection of this PCB to be shut down. * This doesn't deallocate the PCB! * * @param pcb PCB to shutdown * @param shut_rx shut down receive side if this is != 0 * @param shut_tx shut down send side if this is != 0 * @return ERR_OK if shutdown succeeded (or the PCB has already been shut down) * another err_t on error. */ err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx) { if (get_tcp_state(pcb) == LISTEN) { return ERR_CONN; } if (shut_rx) { /* shut down the receive side: set a flag not to receive any more data... */ pcb->flags |= TF_RXCLOSED; if (shut_tx) { /* shutting down the tx AND rx side is the same as closing for the raw API */ return tcp_close_shutdown(pcb, 1); } /* ... and free buffered data */ if (pcb->refused_data != NULL) { pbuf_free(pcb->refused_data); pcb->refused_data = NULL; } } if (shut_tx) { /* This can't happen twice since if it succeeds, the pcb's state is changed. Only close in these states as the others directly deallocate the PCB */ switch (get_tcp_state(pcb)) { case SYN_RCVD: case ESTABLISHED: case CLOSE_WAIT: return tcp_close_shutdown(pcb, 0); default: /* Not (yet?) connected, cannot shutdown the TX side as that would bring us into CLOSED state, where the PCB is deallocated. */ return ERR_CONN; } } /* @todo: return another err_t if not in correct state or already shut? */ return ERR_OK; } /** * Abandons a connection and optionally sends a RST to the remote * host. Deletes the local protocol control block. This is done when * a connection is killed because of shortage of memory. * * @param pcb the tcp_pcb to abort * @param reset boolean to indicate whether a reset should be sent */ void tcp_abandon(struct tcp_pcb *pcb, int reset) { u32_t seqno, ackno; u16_t remote_port, local_port; ip_addr_t remote_ip, local_ip; #if LWIP_CALLBACK_API tcp_err_fn errf; #endif /* LWIP_CALLBACK_API */ void *errf_arg; /* get_tcp_state(pcb) LISTEN not allowed here */ LWIP_ASSERT("don't call tcp_abort/tcp_abandon for listen-pcbs", get_tcp_state(pcb) != LISTEN); /* Figure out on which TCP PCB list we are, and remove us. If we are in an active state, call the receive function associated with the PCB with a NULL argument, and send an RST to the remote end. */ if (get_tcp_state(pcb) == TIME_WAIT) { tcp_pcb_remove(pcb); } else { int send_rst = reset && (get_tcp_state(pcb) != CLOSED); seqno = pcb->snd_nxt; ackno = pcb->rcv_nxt; ip_addr_copy(local_ip, pcb->local_ip); ip_addr_copy(remote_ip, pcb->remote_ip); local_port = pcb->local_port; remote_port = pcb->remote_port; #if LWIP_CALLBACK_API errf = pcb->errf; #endif /* LWIP_CALLBACK_API */ errf_arg = pcb->my_container; tcp_pcb_remove(pcb); if (pcb->unacked != NULL) { tcp_tx_segs_free(pcb, pcb->unacked); pcb->unacked = NULL; } if (pcb->unsent != NULL) { tcp_tx_segs_free(pcb, pcb->unsent); pcb->unsent = NULL; } #if TCP_QUEUE_OOSEQ if (pcb->ooseq != NULL) { tcp_segs_free(pcb, pcb->ooseq); } #endif /* TCP_QUEUE_OOSEQ */ TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT); if (send_rst) { LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n")); tcp_rst(seqno, ackno, local_port, remote_port, pcb); } } (void)local_ip; /* Fix warning -Wunused-but-set-variable */ (void)remote_ip; /* Fix warning -Wunused-but-set-variable */ } /** * Aborts the connection by sending a RST (reset) segment to the remote * host. The pcb is deallocated. This function never fails. * * ATTENTION: When calling this from one of the TCP callbacks, make * sure you always return ERR_ABRT (and never return ERR_ABRT otherwise * or you will risk accessing deallocated memory or memory leaks! * * @param pcb the tcp pcb to abort */ void tcp_abort(struct tcp_pcb *pcb) { tcp_abandon(pcb, 1); } /** * Binds the connection to a local portnumber and IP address. If the * IP address is not given (i.e., ipaddr == NULL), the IP address of * the outgoing network interface is used instead. * * @param pcb the tcp_pcb to bind (no check is done whether this pcb is * already bound!) * @param ipaddr the local ip address to bind to (use IP_ADDR_ANY to bind * to any local address * @param port the local port to bind to * @return ERR_USE if the port is already in use * ERR_OK if bound */ err_t tcp_bind(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port) { LWIP_ERROR("tcp_bind: can only bind in state CLOSED", get_tcp_state(pcb) == CLOSED, return ERR_ISCONN); if (!ip_addr_isany(ipaddr)) { pcb->local_ip = *ipaddr; } pcb->local_port = port; LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port)); return ERR_OK; } #if LWIP_CALLBACK_API /** * Default accept callback if no accept callback is specified by the user. */ static err_t tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err) { LWIP_UNUSED_ARG(arg); LWIP_UNUSED_ARG(pcb); LWIP_UNUSED_ARG(err); return ERR_ABRT; } #endif /* LWIP_CALLBACK_API */ /** * Set the state of the connection to be LISTEN, which means that it * is able to accept incoming connections. * * @param listen_pcb used for listening * @param pcb the original tcp_pcb * @return ERR_ISCONN if the conn_pcb is already in LISTEN state * and ERR_OK on success * */ err_t tcp_listen(struct tcp_pcb_listen *listen_pcb, struct tcp_pcb *pcb) { /* * LWIP_ERROR("tcp_listen: conn_pcb already connected", get_tcp_state(pcb) == CLOSED, ERR_ISCONN); */ /* already listening? */ if (!listen_pcb || (!pcb || get_tcp_state(pcb) == LISTEN)) { return ERR_ISCONN; } listen_pcb->callback_arg = pcb->callback_arg; listen_pcb->local_port = pcb->local_port; set_tcp_state(listen_pcb, LISTEN); listen_pcb->prio = pcb->prio; listen_pcb->so_options = pcb->so_options; listen_pcb->so_options |= SOF_ACCEPTCONN; listen_pcb->ttl = pcb->ttl; listen_pcb->tos = pcb->tos; ip_addr_copy(listen_pcb->local_ip, pcb->local_ip); #if LWIP_CALLBACK_API listen_pcb->accept = tcp_accept_null; #endif /* LWIP_CALLBACK_API */ return ERR_OK; } /** * Update the state that tracks the available window space to advertise. * * Returns how much extra window would be advertised if we sent an * update now. */ u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb) { u32_t new_right_edge = pcb->rcv_nxt + pcb->rcv_wnd; if (TCP_SEQ_GEQ(new_right_edge, pcb->rcv_ann_right_edge + LWIP_MIN((pcb->rcv_wnd_max / 2), pcb->mss))) { /* we can advertise more window */ pcb->rcv_ann_wnd = pcb->rcv_wnd; return new_right_edge - pcb->rcv_ann_right_edge; } else { if (TCP_SEQ_GT(pcb->rcv_nxt, pcb->rcv_ann_right_edge)) { /* Can happen due to other end sending out of advertised window, * but within actual available (but not yet advertised) window */ pcb->rcv_ann_wnd = 0; } else { /* keep the right edge of window constant */ u32_t new_rcv_ann_wnd = pcb->rcv_ann_right_edge - pcb->rcv_nxt; LWIP_ASSERT("new_rcv_ann_wnd <= 0xffff00", new_rcv_ann_wnd <= 0xffff00); pcb->rcv_ann_wnd = new_rcv_ann_wnd; } return 0; } } /** * This function should be called by the application when it has * processed the data. The purpose is to advertise a larger window * when the data has been processed. * * @param pcb the tcp_pcb for which data is read * @param len the amount of bytes that have been read by the application */ void tcp_recved(struct tcp_pcb *pcb, u32_t len) { u32_t wnd_inflation; LWIP_ASSERT("tcp_recved: len would wrap rcv_wnd\n", len <= 0xffffffffU - pcb->rcv_wnd ); pcb->rcv_wnd += len; if (pcb->rcv_wnd > pcb->rcv_wnd_max) { pcb->rcv_wnd = pcb->rcv_wnd_max; } else if(pcb->rcv_wnd == 0) { /* rcv_wnd overflowed */ if ((get_tcp_state(pcb) == CLOSE_WAIT) || (get_tcp_state(pcb) == LAST_ACK)) { /* In passive close, we allow this, since the FIN bit is added to rcv_wnd by the stack itself, since it is not mandatory for an application to call tcp_recved() for the FIN bit, but e.g. the netconn API does so. */ pcb->rcv_wnd = pcb->rcv_wnd_max; } else { LWIP_ASSERT("tcp_recved: len wrapped rcv_wnd\n", 0); } } wnd_inflation = tcp_update_rcv_ann_wnd(pcb); /* If the change in the right edge of window is significant (default * watermark is TCP_WND/4), then send an explicit update now. * Otherwise wait for a packet to be sent in the normal course of * events (or more window to be available later) */ if (wnd_inflation >= TCP_WND_UPDATE_THRESHOLD) { tcp_ack_now(pcb); tcp_output(pcb); } LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n", len, pcb->rcv_wnd, TCP_WND_SCALED(pcb) - pcb->rcv_wnd)); } /** * Connects to another host. The function given as the "connected" * argument will be called when the connection has been established. * * @param pcb the tcp_pcb used to establish the connection * @param ipaddr the remote ip address to connect to * @param port the remote tcp port to connect to * @param connected callback function to call when connected (or on error) * @return ERR_VAL if invalid arguments are given * ERR_OK if connect request has been sent * other err_t values if connect request couldn't be sent */ err_t tcp_connect(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port, tcp_connected_fn connected) { err_t ret; u32_t iss; LWIP_ERROR("tcp_connect: can only connected from state CLOSED", get_tcp_state(pcb) == CLOSED, return ERR_ISCONN); LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port)); if (ipaddr != NULL) { pcb->remote_ip = *ipaddr; } else { return ERR_VAL; } pcb->remote_port = port; /* check if we have a route to the remote host */ if (ip_addr_isany(&(pcb->local_ip))) { LWIP_ASSERT("tcp_connect: need to find route to host", 0); } if (pcb->local_port == 0) { return ERR_VAL; } iss = tcp_next_iss(); pcb->rcv_nxt = 0; pcb->snd_nxt = iss; pcb->lastack = iss - 1; pcb->snd_lbb = iss - 1; pcb->rcv_ann_right_edge = pcb->rcv_nxt; pcb->snd_wnd = TCP_WND; /* * For effective and advertized MSS without MTU consideration: * If MSS is configured - do not accept a higher value than 536 * If MSS is not configured assume minimum value of 536 * The send MSS is updated when an MSS option is received */ u16_t snd_mss = pcb->advtsd_mss = (LWIP_TCP_MSS) ? ((LWIP_TCP_MSS > 536) ? 536 : LWIP_TCP_MSS) : 536; UPDATE_PCB_BY_MSS(pcb, snd_mss); #if TCP_CALCULATE_EFF_SEND_MSS /* * For advertized MSS with MTU knowledge - it is highly likely that it can be derived from the MTU towards the remote IP address. * Otherwise (if unlikely MTU==0) * If LWIP_TCP_MSS>0 use it as MSS * If LWIP_TCP_MSS==0 set advertized MSS value to default 536 */ pcb->advtsd_mss = (LWIP_TCP_MSS > 0) ? tcp_eff_send_mss(LWIP_TCP_MSS, pcb) : tcp_mss_follow_mtu_with_default(536, pcb); /* * For effective MSS with MTU knowledge - get the minimum between pcb->mss and the MSS derived from the * MTU towards the remote IP address * */ u16_t eff_mss = tcp_eff_send_mss(pcb->mss, pcb); UPDATE_PCB_BY_MSS(pcb, eff_mss); #endif /* TCP_CALCULATE_EFF_SEND_MSS */ pcb->cwnd = 1; pcb->ssthresh = pcb->mss * 10; pcb->connected = connected; /* Send a SYN together with the MSS option. */ ret = tcp_enqueue_flags(pcb, TCP_SYN); if (ret == ERR_OK) { /* SYN segment was enqueued, changed the pcbs state now */ set_tcp_state(pcb, SYN_SENT); tcp_output(pcb); } return ret; } /** * Called every slow_tmr_interval ms and implements the retransmission timer and the timer that * closes the psb if it in TIME_WAIT state for enough time. It also increments * various timers such as the inactivity timer in PCB. * * Automatically called from tcp_tmr(). */ void tcp_slowtmr(struct tcp_pcb* pcb) { #if !TCP_CC_ALGO_MOD u32_t eff_wnd; #endif //!TCP_CC_ALGO_MOD u8_t pcb_remove; /* flag if a PCB should be removed */ u8_t pcb_reset; /* flag if a RST should be sent when removing */ err_t err; err = ERR_OK; if (pcb == NULL) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n")); } if (pcb && PCB_IN_ACTIVE_STATE(pcb)) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n")); LWIP_ASSERT("tcp_slowtmr: active get_tcp_state(pcb) != CLOSED\n", get_tcp_state(pcb) != CLOSED); LWIP_ASSERT("tcp_slowtmr: active get_tcp_state(pcb) != LISTEN\n", get_tcp_state(pcb) != LISTEN); LWIP_ASSERT("tcp_slowtmr: active get_tcp_state(pcb) != TIME-WAIT\n", get_tcp_state(pcb) != TIME_WAIT); pcb_remove = 0; pcb_reset = 0; if (get_tcp_state(pcb) == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) { ++pcb_remove; err = ERR_TIMEOUT; LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n")); } else if (pcb->nrtx == TCP_MAXRTX) { ++pcb_remove; err = ERR_ABRT; LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n")); } else { if (pcb->persist_backoff > 0) { /* If snd_wnd is zero and pcb->unacked is NULL , use persist timer to send 1 byte probes * instead of using the standard retransmission mechanism. */ pcb->persist_cnt++; if (pcb->persist_cnt >= tcp_persist_backoff[pcb->persist_backoff-1]) { pcb->persist_cnt = 0; if (pcb->persist_backoff < sizeof(tcp_persist_backoff)) { pcb->persist_backoff++; } /* Use tcp_keepalive() instead of tcp_zero_window_probe() to probe for window update * without sending any data (which will force us to split the segment). * tcp_zero_window_probe(pcb); */ tcp_keepalive(pcb); } } else { /* Increase the retransmission timer if it is running */ if(pcb->rtime >= 0) ++pcb->rtime; if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) { /* Time for a retransmission. */ LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"S16_F " pcb->rto %"S16_F"\n", pcb->rtime, pcb->rto)); /* Double retransmission time-out unless we are trying to * connect to somebody (i.e., we are in SYN_SENT). */ if (get_tcp_state(pcb) != SYN_SENT) { pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx]; } /* Reset the retransmission timer. */ pcb->rtime = 0; #if TCP_CC_ALGO_MOD cc_cong_signal(pcb, CC_RTO); #else /* Reduce congestion window and ssthresh. */ eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd); pcb->ssthresh = eff_wnd >> 1; if (pcb->ssthresh < (u32_t)(pcb->mss << 1)) { pcb->ssthresh = (pcb->mss << 1); } pcb->cwnd = pcb->mss; #endif LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F " ssthresh %"U16_F"\n", pcb->cwnd, pcb->ssthresh)); /* The following needs to be called AFTER cwnd is set to one mss - STJ */ tcp_rexmit_rto(pcb); } } } /* Check if this PCB has stayed too long in FIN-WAIT-2 */ if (get_tcp_state(pcb) == FIN_WAIT_2) { /* If this PCB is in FIN_WAIT_2 because of SHUT_WR don't let it time out. */ if (pcb->flags & TF_RXCLOSED) { /* PCB was fully closed (either through close() or SHUT_RDWR): normal FIN-WAIT timeout handling. */ if ((u32_t)(tcp_ticks - pcb->tmr) > TCP_FIN_WAIT_TIMEOUT / slow_tmr_interval) { ++pcb_remove; err = ERR_ABRT; LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n")); } } } /* Check if KEEPALIVE should be sent */ if((pcb->so_options & SOF_KEEPALIVE) && ((get_tcp_state(pcb) == ESTABLISHED) || (get_tcp_state(pcb) == CLOSE_WAIT))) { #if LWIP_TCP_KEEPALIVE if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keep_idle + (pcb->keep_cnt*pcb->keep_intvl)) / slow_tmr_interval) #else if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keep_idle + TCP_MAXIDLE) / slow_tmr_interval) #endif /* LWIP_TCP_KEEPALIVE */ { LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n", ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip), ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip))); ++pcb_remove; err = ERR_ABRT; ++pcb_reset; } #if LWIP_TCP_KEEPALIVE else if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keep_idle + pcb->keep_cnt_sent * pcb->keep_intvl) / slow_tmr_interval) #else else if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEPINTVL_DEFAULT) / slow_tmr_interval) #endif /* LWIP_TCP_KEEPALIVE */ { tcp_keepalive(pcb); pcb->keep_cnt_sent++; } } /* If this PCB has queued out of sequence data, but has been inactive for too long, will drop the data (it will eventually be retransmitted). */ #if TCP_QUEUE_OOSEQ if (pcb->ooseq != NULL && (u32_t)tcp_ticks - pcb->tmr >= pcb->rto * TCP_OOSEQ_TIMEOUT) { tcp_segs_free(pcb, pcb->ooseq); pcb->ooseq = NULL; LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n")); } #endif /* TCP_QUEUE_OOSEQ */ /* Check if this PCB has stayed too long in SYN-RCVD */ if (get_tcp_state(pcb) == SYN_RCVD) { if ((u32_t)(tcp_ticks - pcb->tmr) > TCP_SYN_RCVD_TIMEOUT / slow_tmr_interval) { ++pcb_remove; err = ERR_ABRT; LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n")); } } /* Check if this PCB has stayed too long in LAST-ACK */ if (get_tcp_state(pcb) == LAST_ACK) { if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / slow_tmr_interval) { ++pcb_remove; err = ERR_ABRT; LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n")); } } /* If the PCB should be removed, do it. */ if (pcb_remove) { tcp_pcb_purge(pcb); TCP_EVENT_ERR(pcb->errf, pcb->my_container, err); if (pcb_reset) { tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, pcb->local_port, pcb->remote_port, pcb); } set_tcp_state(pcb, CLOSED); } else { /* We check if we should poll the connection. */ ++pcb->polltmr; if (pcb->polltmr >= pcb->pollinterval) { pcb->polltmr = 0; LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n")); TCP_EVENT_POLL(pcb, err); /* if err == ERR_ABRT, 'prev' is already deallocated */ if (err == ERR_OK) { tcp_output(pcb); } } } } if (pcb && PCB_IN_TIME_WAIT_STATE(pcb)) { LWIP_ASSERT("tcp_slowtmr: TIME-WAIT get_tcp_state(pcb) == TIME-WAIT", get_tcp_state(pcb) == TIME_WAIT); pcb_remove = 0; /* Check if this PCB has stayed long enough in TIME-WAIT */ if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / slow_tmr_interval) { ++pcb_remove; /* err = ERR_ABRT; */ /* Note: suppress warning 'err' is never read */ } /* If the PCB should be removed, do it. */ if (pcb_remove) { tcp_pcb_purge(pcb); set_tcp_state(pcb, CLOSED); } } } /** * Is called every slow_tmr_interval and process data previously * "refused" by upper layer (application) and sends delayed ACKs. * * Automatically called from tcp_tmr(). */ void tcp_fasttmr(struct tcp_pcb* pcb) { if(pcb != NULL && PCB_IN_ACTIVE_STATE(pcb)) { /* If there is data which was previously "refused" by upper layer */ while (pcb->refused_data != NULL) { // 'while' instead of 'if' because windows scale uses large pbuf struct pbuf *rest; /* Notify again application with data previously received. */ err_t err; pbuf_split_64k(pcb->refused_data, &rest); LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_fasttmr: notify kept packet\n")); TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err); if (err == ERR_OK) { pcb->refused_data = rest; } else { if (rest) { pbuf_cat(pcb->refused_data, rest); /* undo splitting */ } if (err == ERR_ABRT) { /* if err == ERR_ABRT, 'pcb' is already deallocated */ pcb = NULL; } break; } } /* send delayed ACKs */ if (pcb && (pcb->flags & TF_ACK_DELAY)) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n")); tcp_ack_now(pcb); tcp_output(pcb); pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW); } } } /** * Deallocates a list of TCP segments (tcp_seg structures). * * @param seg tcp_seg list of TCP segments to free */ void tcp_segs_free(struct tcp_pcb *pcb, struct tcp_seg *seg) { while (seg != NULL) { struct tcp_seg *next = seg->next; seg->next = NULL; tcp_seg_free(pcb, seg); seg = next; } } /** * Frees a TCP segment (tcp_seg structure). * * @param seg single tcp_seg to free */ void tcp_seg_free(struct tcp_pcb *pcb, struct tcp_seg *seg) { if (seg != NULL) { if (seg->p != NULL) { pbuf_free(seg->p); #if TCP_DEBUG seg->p = NULL; #endif /* TCP_DEBUG */ } external_tcp_seg_free(pcb, seg); } } /** * Deallocates a list of TCP segments (tcp_seg structures). * * @param seg tcp_seg list of TCP segments to free */ void tcp_tx_segs_free(struct tcp_pcb * pcb, struct tcp_seg *seg) { while (seg != NULL) { struct tcp_seg *next = seg->next; seg->next = NULL; tcp_tx_seg_free(pcb, seg); seg = next; } } /** * Frees a TCP segment (tcp_seg structure). * * @param seg single tcp_seg to free */ void tcp_tx_seg_free(struct tcp_pcb * pcb, struct tcp_seg *seg) { if (seg != NULL) { if (seg->p != NULL) { tcp_tx_pbuf_free(pcb, seg->p); } external_tcp_seg_free(pcb, seg); } } #if TCP_QUEUE_OOSEQ /** * Returns a copy of the given TCP segment. * The pbuf and data are not copied, only the pointers * * @param seg the old tcp_seg * @return a copy of seg */ struct tcp_seg * tcp_seg_copy(struct tcp_pcb* pcb, struct tcp_seg *seg) { struct tcp_seg *cseg; cseg = external_tcp_seg_alloc(pcb); if (cseg == NULL) { return NULL; } SMEMCPY((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg)); pbuf_ref(cseg->p); return cseg; } #endif /* TCP_QUEUE_OOSEQ */ #if LWIP_CALLBACK_API /** * Default receive callback that is called if the user didn't register * a recv callback for the pcb. */ err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err) { LWIP_UNUSED_ARG(arg); if (p != NULL) { tcp_recved(pcb, (u32_t)p->tot_len); pbuf_free(p); } else if (err == ERR_OK) { return tcp_close(pcb); } return ERR_OK; } #endif /* LWIP_CALLBACK_API */ void tcp_pcb_init (struct tcp_pcb* pcb, u8_t prio) { u32_t iss; memset(pcb, 0, sizeof(*pcb)); pcb->max_snd_buff = TCP_SND_BUF; pcb->prio = prio; pcb->snd_buf = pcb->max_snd_buff; pcb->snd_queuelen = 0; pcb->snd_scale = 0; pcb->rcv_scale = 0; pcb->rcv_wnd = TCP_WND_SCALED(pcb); pcb->rcv_ann_wnd = TCP_WND_SCALED(pcb); pcb->rcv_wnd_max = TCP_WND_SCALED(pcb); pcb->rcv_wnd_max_desired = TCP_WND_SCALED(pcb); pcb->tos = 0; pcb->ttl = TCP_TTL; /* As initial send MSS, we use TCP_MSS but limit it to 536. The send MSS is updated when an MSS option is received. */ u16_t snd_mss = pcb->advtsd_mss = (LWIP_TCP_MSS) ? ((LWIP_TCP_MSS > 536) ? 536 : LWIP_TCP_MSS) : 536; UPDATE_PCB_BY_MSS(pcb, snd_mss); pcb->max_unsent_len = pcb->max_tcp_snd_queuelen; pcb->rto = 3000 / slow_tmr_interval; pcb->sa = 0; pcb->sv = 3000 / slow_tmr_interval; pcb->rtime = -1; #if TCP_CC_ALGO_MOD switch (lwip_cc_algo_module) { case CC_MOD_CUBIC: pcb->cc_algo = &cubic_cc_algo; break; case CC_MOD_NONE: pcb->cc_algo = &none_cc_algo; break; case CC_MOD_LWIP: default: pcb->cc_algo = &lwip_cc_algo; break; } cc_init(pcb); #endif pcb->cwnd = 1; iss = tcp_next_iss(); pcb->snd_wl2 = iss; pcb->snd_nxt = iss; pcb->lastack = iss; pcb->snd_lbb = iss; pcb->tmr = tcp_ticks; pcb->snd_sml_snt = 0; pcb->snd_sml_add = 0; pcb->polltmr = 0; pcb->tcp_timer = 0; #if LWIP_CALLBACK_API pcb->recv = tcp_recv_null; #endif /* LWIP_CALLBACK_API */ /* Init KEEPALIVE timer */ pcb->keep_idle = TCP_KEEPIDLE_DEFAULT; #if LWIP_TCP_KEEPALIVE pcb->keep_intvl = TCP_KEEPINTVL_DEFAULT; pcb->keep_cnt = TCP_KEEPCNT_DEFAULT; #endif /* LWIP_TCP_KEEPALIVE */ pcb->keep_cnt_sent = 0; pcb->quickack = 0; pcb->enable_ts_opt = enable_ts_option; pcb->seg_alloc = NULL; pcb->pbuf_alloc = NULL; } struct pbuf * tcp_tx_pbuf_alloc(struct tcp_pcb * pcb, u16_t length, pbuf_type type) { struct pbuf * p; if (!pcb->pbuf_alloc) { // pbuf_alloc is not valid, we should allocate a new pbuf. p = external_tcp_tx_pbuf_alloc(pcb); if (!p) return NULL; p->next = NULL; p->type = type; /* set reference count */ p->ref = 1; /* set flags */ p->flags = 0; } else { // pbuf_alloc is valid, we dont need to allocate a new pbuf element. p = pcb->pbuf_alloc; pcb->pbuf_alloc = NULL; } /* Set up internal structure of the pbuf. */ p->len = p->tot_len = length; return p; } // Release preallocated buffers void tcp_tx_preallocted_buffers_free(struct tcp_pcb * pcb) { if (pcb->seg_alloc) { tcp_tx_seg_free(pcb, pcb->seg_alloc); pcb->seg_alloc = NULL; } if (pcb->pbuf_alloc) { tcp_tx_pbuf_free(pcb, pcb->pbuf_alloc); pcb->pbuf_alloc = NULL; } } void tcp_tx_pbuf_free(struct tcp_pcb * pcb, struct pbuf * p) { struct pbuf * p_next = NULL; while (p) { p_next = p->next; p->next = NULL; if (p->type == PBUF_RAM) { external_tcp_tx_pbuf_free(pcb, p); } else { pbuf_free(p); } p = p_next; } } /** * Used to specify the argument that should be passed callback * functions. * * @param pcb tcp_pcb to set the callback argument * @param arg void pointer argument to pass to callback functions */ void tcp_arg(struct tcp_pcb *pcb, void *arg) { pcb->callback_arg = arg; } #if LWIP_CALLBACK_API /** * Used to specify the function that should be called when a TCP * connection receives data. * * @param pcb tcp_pcb to set the recv callback * @param recv callback function to call for this pcb when data is received */ void tcp_recv(struct tcp_pcb *pcb, tcp_recv_fn recv) { pcb->recv = recv; } /** * Used to specify the function that should be called when TCP data * has been successfully delivered to the remote host. * * @param pcb tcp_pcb to set the sent callback * @param sent callback function to call for this pcb when data is successfully sent */ void tcp_sent(struct tcp_pcb *pcb, tcp_sent_fn sent) { pcb->sent = sent; } /** * Used to specify the function that should be called when a fatal error * has occured on the connection. * * @param pcb tcp_pcb to set the err callback * @param err callback function to call for this pcb when a fatal error * has occured on the connection */ void tcp_err(struct tcp_pcb *pcb, tcp_err_fn err) { pcb->errf = err; } /** * Used for specifying the function that should be called when a * LISTENing connection has been connected to another host. * * @param pcb tcp_pcb to set the accept callback * @param accept callback function to call for this pcb when LISTENing * connection has been connected to another host */ void tcp_accept(struct tcp_pcb *pcb, tcp_accept_fn accept) { pcb->accept = accept; } /** * Used for specifying the function that should be called * for sending packets. * * @param pcb tcp_pcb to set the outputcallback * @param output callback function */ void tcp_ip_output(struct tcp_pcb *pcb, ip_output_fn ip_output) { pcb->ip_output = ip_output; } /** * Used for specifying the function that should be called when a * SYN was received. * * @param pcb tcp_pcb to set the accept callback * @param accept callback function to call for this pcb when SYN * is received */ void tcp_syn_handled(struct tcp_pcb_listen *pcb, tcp_syn_handled_fn syn_handled) { pcb->syn_handled_cb = syn_handled; } /** * Used for specifying the function that should be called to clone pcb * * @param listen pcb to clone * @param clone callback function to call in order to clone the pcb */ void tcp_clone_conn(struct tcp_pcb_listen *pcb, tcp_clone_conn_fn clone_conn) { pcb->clone_conn = clone_conn; } #endif /* LWIP_CALLBACK_API */ /** * Used to specify the function that should be called periodically * from TCP. The interval is specified in terms of the TCP coarse * timer interval, which is called twice a second. * */ void tcp_poll(struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval) { #if LWIP_CALLBACK_API pcb->poll = poll; #else /* LWIP_CALLBACK_API */ LWIP_UNUSED_ARG(poll); #endif /* LWIP_CALLBACK_API */ pcb->pollinterval = interval; } /** * Purges a TCP PCB. Removes any buffered data and frees the buffer memory * (pcb->ooseq, pcb->unsent and pcb->unacked are freed). * * @param pcb tcp_pcb to purge. The pcb itself is not deallocated! */ void tcp_pcb_purge(struct tcp_pcb *pcb) { if (get_tcp_state(pcb) != CLOSED && get_tcp_state(pcb) != TIME_WAIT && get_tcp_state(pcb) != LISTEN) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n")); if (pcb->refused_data != NULL) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->refused_data\n")); pbuf_free(pcb->refused_data); pcb->refused_data = NULL; } if (pcb->unsent != NULL) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n")); } if (pcb->unacked != NULL) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n")); } #if TCP_QUEUE_OOSEQ if (pcb->ooseq != NULL) { LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n")); } tcp_segs_free(pcb, pcb->ooseq); pcb->ooseq = NULL; #endif /* TCP_QUEUE_OOSEQ */ /* Stop the retransmission timer as it will expect data on unacked queue if it fires */ pcb->rtime = -1; tcp_tx_segs_free(pcb, pcb->unsent); tcp_tx_segs_free(pcb, pcb->unacked); pcb->unacked = pcb->unsent = NULL; #if TCP_OVERSIZE pcb->unsent_oversize = 0; #endif /* TCP_OVERSIZE */ #if TCP_CC_ALGO_MOD cc_destroy(pcb); #endif } } /** * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first. * * @param pcblist PCB list to purge. * @param pcb tcp_pcb to purge. The pcb itself is NOT deallocated! */ void tcp_pcb_remove(struct tcp_pcb *pcb) { tcp_pcb_purge(pcb); /* if there is an outstanding delayed ACKs, send it */ if (get_tcp_state(pcb) != TIME_WAIT && get_tcp_state(pcb) != LISTEN && pcb->flags & TF_ACK_DELAY) { pcb->flags |= TF_ACK_NOW; tcp_output(pcb); } if (get_tcp_state(pcb) != LISTEN) { LWIP_ASSERT("unsent segments leaking", pcb->unsent == NULL); LWIP_ASSERT("unacked segments leaking", pcb->unacked == NULL); #if TCP_QUEUE_OOSEQ LWIP_ASSERT("ooseq segments leaking", pcb->ooseq == NULL); #endif /* TCP_QUEUE_OOSEQ */ } set_tcp_state(pcb, CLOSED); LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane()); } /** * Calculates a new initial sequence number for new connections. * * @return u32_t pseudo random sequence number */ u32_t tcp_next_iss(void) { static u32_t iss = 6510; iss += tcp_ticks; /* XXX */ return iss; } #if TCP_CALCULATE_EFF_SEND_MSS /** * Calcluates the effective send mss that can be used for a specific IP address * by using ip_route to determine the netif used to send to the address and * calculating the minimum of TCP_MSS and that netif's mtu (if set). */ u16_t tcp_eff_send_mss(u16_t sendmss, struct tcp_pcb *pcb) { u16_t mtu; mtu = external_ip_route_mtu(pcb); if (mtu != 0) { sendmss = LWIP_MIN(sendmss, mtu - IP_HLEN - TCP_HLEN); } return sendmss; } /** * Calcluates the send mss that can be used for a specific IP address * by using ip_route to determine the netif used to send to the address. * In case MTU is unkonw - return the default MSS */ u16_t tcp_mss_follow_mtu_with_default(u16_t defsendmss, struct tcp_pcb *pcb) { u16_t mtu; mtu = external_ip_route_mtu(pcb); if (mtu != 0) { defsendmss = mtu - IP_HLEN - TCP_HLEN; defsendmss = LWIP_MAX(defsendmss, 1); /* MSS must be a positive number */ } return defsendmss; } #endif /* TCP_CALCULATE_EFF_SEND_MSS */ #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG /** * Print a tcp header for debugging purposes. * * @param tcphdr pointer to a struct tcp_hdr */ void tcp_debug_print(struct tcp_hdr *tcphdr) { LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n")); LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(TCP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n", ntohs(tcphdr->src), ntohs(tcphdr->dest))); LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n", ntohl(tcphdr->seqno))); LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n", ntohl(tcphdr->ackno))); LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" | |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"| %5"U16_F" | (hdrlen, flags (", TCPH_HDRLEN(tcphdr), TCPH_FLAGS(tcphdr) >> 5 & 1, TCPH_FLAGS(tcphdr) >> 4 & 1, TCPH_FLAGS(tcphdr) >> 3 & 1, TCPH_FLAGS(tcphdr) >> 2 & 1, TCPH_FLAGS(tcphdr) >> 1 & 1, TCPH_FLAGS(tcphdr) & 1, ntohs(tcphdr->wnd))); tcp_debug_print_flags(TCPH_FLAGS(tcphdr)); LWIP_DEBUGF(TCP_DEBUG, ("), win)\n")); LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(TCP_DEBUG, ("| 0x%04"X16_F" | %5"U16_F" | (chksum, urgp)\n", ntohs(tcphdr->chksum), ntohs(tcphdr->urgp))); LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); } /** * Print a tcp state for debugging purposes. * * @param s enum tcp_state to print */ void tcp_debug_print_state(enum tcp_state s) { LWIP_UNUSED_ARG(s); LWIP_DEBUGF(TCP_DEBUG, ("State: %s\n", tcp_state_str[s])); } /** * Print tcp flags for debugging purposes. * * @param flags tcp flags, all active flags are printed */ void tcp_debug_print_flags(u8_t flags) { if (flags & TCP_FIN) { LWIP_DEBUGF(TCP_DEBUG, ("FIN ")); } if (flags & TCP_SYN) { LWIP_DEBUGF(TCP_DEBUG, ("SYN ")); } if (flags & TCP_RST) { LWIP_DEBUGF(TCP_DEBUG, ("RST ")); } if (flags & TCP_PSH) { LWIP_DEBUGF(TCP_DEBUG, ("PSH ")); } if (flags & TCP_ACK) { LWIP_DEBUGF(TCP_DEBUG, ("ACK ")); } if (flags & TCP_URG) { LWIP_DEBUGF(TCP_DEBUG, ("URG ")); } if (flags & TCP_ECE) { LWIP_DEBUGF(TCP_DEBUG, ("ECE ")); } if (flags & TCP_CWR) { LWIP_DEBUGF(TCP_DEBUG, ("CWR ")); } LWIP_DEBUGF(TCP_DEBUG, ("\n")); } /** * Print all tcp_pcbs in every list for debugging purposes. */ void tcp_debug_print_pcbs(void) { LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states: REMOVED\n")); } #endif /* TCP_DEBUG */ #endif /* LWIP_TCP */