Simon Ford
Version of http://mbed.org/cookbook/NetServicesTribute with setting set the same for LPC2368
Dependents: UDPSocketExample 24LCxx_I2CApp WeatherPlatform_pachube HvZServerLib ... more
Diff: lwip/core/tcp.c
- Revision:
- 0:350011bf8be7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/lwip/core/tcp.c Tue Nov 23 14:15:36 2010 +0000
@@ -0,0 +1,1631 @@
+/**
+ * @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 <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/snmp.h"
+#include "lwip/tcp.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/debug.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+const char * const tcp_state_str[] = {
+ "CLOSED",
+ "LISTEN",
+ "SYN_SENT",
+ "SYN_RCVD",
+ "ESTABLISHED",
+ "FIN_WAIT_1",
+ "FIN_WAIT_2",
+ "CLOSE_WAIT",
+ "CLOSING",
+ "LAST_ACK",
+ "TIME_WAIT"
+};
+
+/* Incremented every coarse grained timer shot (typically every 500 ms). */
+u32_t tcp_ticks;
+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 };
+
+/* The TCP PCB lists. */
+
+/** List of all TCP PCBs bound but not yet (connected || listening) */
+struct tcp_pcb *tcp_bound_pcbs;
+/** List of all TCP PCBs in LISTEN state */
+union tcp_listen_pcbs_t tcp_listen_pcbs;
+/** List of all TCP PCBs that are in a state in which
+ * they accept or send data. */
+struct tcp_pcb *tcp_active_pcbs;
+/** List of all TCP PCBs in TIME-WAIT state */
+struct tcp_pcb *tcp_tw_pcbs;
+
+#define NUM_TCP_PCB_LISTS 4
+#define NUM_TCP_PCB_LISTS_NO_TIME_WAIT 3
+/** An array with all (non-temporary) PCB lists, mainly used for smaller code size */
+struct tcp_pcb **tcp_pcb_lists[] = {&tcp_listen_pcbs.pcbs, &tcp_bound_pcbs,
+ &tcp_active_pcbs, &tcp_tw_pcbs};
+
+/** Only used for temporary storage. */
+struct tcp_pcb *tcp_tmp_pcb;
+
+/** Timer counter to handle calling slow-timer from tcp_tmr() */
+static u8_t tcp_timer;
+static u16_t tcp_new_port(void);
+
+/**
+ * Called periodically to dispatch TCP timers.
+ *
+ */
+void
+tcp_tmr(void)
+{
+ /* Call tcp_fasttmr() every 250 ms */
+ tcp_fasttmr();
+
+ if (++tcp_timer & 1) {
+ /* Call tcp_tmr() every 500 ms, i.e., every other timer
+ tcp_tmr() is called. */
+ tcp_slowtmr();
+ }
+}
+
+/**
+ * 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 && (pcb->state != LISTEN)) {
+ if ((pcb->refused_data != NULL) || (pcb->rcv_wnd != TCP_WND)) {
+ /* 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_ip, &pcb->remote_ip,
+ pcb->local_port, pcb->remote_port);
+
+ tcp_pcb_purge(pcb);
+
+ /* TODO: to which state do we move now? */
+
+ /* move to TIME_WAIT since we close actively */
+ TCP_RMV(&tcp_active_pcbs, pcb);
+ pcb->state = TIME_WAIT;
+ TCP_REG(&tcp_tw_pcbs, pcb);
+
+ return ERR_OK;
+ }
+ }
+
+ switch (pcb->state) {
+ 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;
+ TCP_RMV(&tcp_bound_pcbs, pcb);
+ memp_free(MEMP_TCP_PCB, pcb);
+ pcb = NULL;
+ break;
+ case LISTEN:
+ err = ERR_OK;
+ tcp_pcb_remove(&tcp_listen_pcbs.pcbs, pcb);
+ memp_free(MEMP_TCP_PCB_LISTEN, pcb);
+ pcb = NULL;
+ break;
+ case SYN_SENT:
+ err = ERR_OK;
+ tcp_pcb_remove(&tcp_active_pcbs, pcb);
+ memp_free(MEMP_TCP_PCB, pcb);
+ pcb = NULL;
+ snmp_inc_tcpattemptfails();
+ break;
+ case SYN_RCVD:
+ err = tcp_send_fin(pcb);
+ if (err == ERR_OK) {
+ snmp_inc_tcpattemptfails();
+ pcb->state = FIN_WAIT_1;
+ }
+ break;
+ case ESTABLISHED:
+ err = tcp_send_fin(pcb);
+ if (err == ERR_OK) {
+ snmp_inc_tcpestabresets();
+ pcb->state = FIN_WAIT_1;
+ }
+ break;
+ case CLOSE_WAIT:
+ err = tcp_send_fin(pcb);
+ if (err == ERR_OK) {
+ snmp_inc_tcpestabresets();
+ pcb->state = 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(pcb->state);
+#endif /* TCP_DEBUG */
+
+ if (pcb->state != 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 (pcb->state == LISTEN) {
+ return ERR_CONN;
+ }
+ if (shut_rx) {
+ /* shut down the receive side: free buffered data... */
+ if (pcb->refused_data != NULL) {
+ pbuf_free(pcb->refused_data);
+ pcb->refused_data = NULL;
+ }
+ /* ... and set a flag not to receive any more data */
+ pcb->flags |= TF_RXCLOSED;
+ }
+ 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 (pcb->state) {
+ case SYN_RCVD:
+ case ESTABLISHED:
+ case CLOSE_WAIT:
+ return tcp_close_shutdown(pcb, 0);
+ default:
+ /* don't shut down other states */
+ break;
+ }
+ }
+ /* @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;
+
+ /* pcb->state LISTEN not allowed here */
+ LWIP_ASSERT("don't call tcp_abort/tcp_abandon for listen-pcbs",
+ pcb->state != 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 (pcb->state == TIME_WAIT) {
+ tcp_pcb_remove(&tcp_tw_pcbs, pcb);
+ memp_free(MEMP_TCP_PCB, pcb);
+ } else {
+ 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->callback_arg;
+ tcp_pcb_remove(&tcp_active_pcbs, pcb);
+ if (pcb->unacked != NULL) {
+ tcp_segs_free(pcb->unacked);
+ }
+ if (pcb->unsent != NULL) {
+ tcp_segs_free(pcb->unsent);
+ }
+#if TCP_QUEUE_OOSEQ
+ if (pcb->ooseq != NULL) {
+ tcp_segs_free(pcb->ooseq);
+ }
+#endif /* TCP_QUEUE_OOSEQ */
+ memp_free(MEMP_TCP_PCB, pcb);
+ TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
+ if (reset) {
+ LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
+ tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
+ }
+ }
+}
+
+/**
+ * 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)
+{
+ int i;
+ int max_pcb_list = NUM_TCP_PCB_LISTS;
+ struct tcp_pcb *cpcb;
+
+ LWIP_ERROR("tcp_bind: can only bind in state CLOSED", pcb->state == CLOSED, return ERR_ISCONN);
+
+#if SO_REUSE
+ /* Unless the REUSEADDR flag is set,
+ we have to check the pcbs in TIME-WAIT state, also.
+ We do not dump TIME_WAIT pcb's; they can still be matched by incoming
+ packets using both local and remote IP addresses and ports to distinguish.
+ */
+#if SO_REUSE
+ if ((pcb->so_options & SOF_REUSEADDR) != 0) {
+ max_pcb_list = NUM_TCP_PCB_LISTS_NO_TIME_WAIT;
+ }
+#endif /* SO_REUSE */
+#endif /* SO_REUSE */
+
+ if (port == 0) {
+ port = tcp_new_port();
+ }
+
+ /* Check if the address already is in use (on all lists) */
+ for (i = 0; i < max_pcb_list; i++) {
+ for(cpcb = *tcp_pcb_lists[i]; cpcb != NULL; cpcb = cpcb->next) {
+ if (cpcb->local_port == port) {
+#if SO_REUSE
+ /* Omit checking for the same port if both pcbs have REUSEADDR set.
+ For SO_REUSEADDR, the duplicate-check for a 5-tuple is done in
+ tcp_connect. */
+ if (((pcb->so_options & SOF_REUSEADDR) == 0) ||
+ ((cpcb->so_options & SOF_REUSEADDR) == 0))
+#endif /* SO_REUSE */
+ {
+ if (ip_addr_isany(&(cpcb->local_ip)) ||
+ ip_addr_isany(ipaddr) ||
+ ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
+ return ERR_USE;
+ }
+ }
+ }
+ }
+ }
+
+ if (!ip_addr_isany(ipaddr)) {
+ pcb->local_ip = *ipaddr;
+ }
+ pcb->local_port = port;
+ TCP_REG(&tcp_bound_pcbs, pcb);
+ 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. The protocol control block
+ * is reallocated in order to consume less memory. Setting the
+ * connection to LISTEN is an irreversible process.
+ *
+ * @param pcb the original tcp_pcb
+ * @param backlog the incoming connections queue limit
+ * @return tcp_pcb used for listening, consumes less memory.
+ *
+ * @note The original tcp_pcb is freed. This function therefore has to be
+ * called like this:
+ * tpcb = tcp_listen(tpcb);
+ */
+struct tcp_pcb *
+tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog)
+{
+ struct tcp_pcb_listen *lpcb;
+
+ LWIP_UNUSED_ARG(backlog);
+ LWIP_ERROR("tcp_listen: pcb already connected", pcb->state == CLOSED, return NULL);
+
+ /* already listening? */
+ if (pcb->state == LISTEN) {
+ return pcb;
+ }
+#if SO_REUSE
+ if ((pcb->so_options & SOF_REUSEADDR) != 0) {
+ /* Since SOF_REUSEADDR allows reusing a local address before the pcb's usage
+ is declared (listen-/connection-pcb), we have to make sure now that
+ this port is only used once for every local IP. */
+ for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
+ if (lpcb->local_port == pcb->local_port) {
+ if (ip_addr_cmp(&lpcb->local_ip, &pcb->local_ip)) {
+ /* this address/port is already used */
+ return NULL;
+ }
+ }
+ }
+ }
+#endif /* SO_REUSE */
+ lpcb = (struct tcp_pcb_listen *)memp_malloc(MEMP_TCP_PCB_LISTEN);
+ if (lpcb == NULL) {
+ return NULL;
+ }
+ lpcb->callback_arg = pcb->callback_arg;
+ lpcb->local_port = pcb->local_port;
+ lpcb->state = LISTEN;
+ lpcb->prio = pcb->prio;
+ lpcb->so_options = pcb->so_options;
+ lpcb->so_options |= SOF_ACCEPTCONN;
+ lpcb->ttl = pcb->ttl;
+ lpcb->tos = pcb->tos;
+ ip_addr_copy(lpcb->local_ip, pcb->local_ip);
+ TCP_RMV(&tcp_bound_pcbs, pcb);
+ memp_free(MEMP_TCP_PCB, pcb);
+#if LWIP_CALLBACK_API
+ lpcb->accept = tcp_accept_null;
+#endif /* LWIP_CALLBACK_API */
+#if TCP_LISTEN_BACKLOG
+ lpcb->accepts_pending = 0;
+ lpcb->backlog = (backlog ? backlog : 1);
+#endif /* TCP_LISTEN_BACKLOG */
+ TCP_REG(&tcp_listen_pcbs.pcbs, (struct tcp_pcb *)lpcb);
+ return (struct tcp_pcb *)lpcb;
+}
+
+/**
+ * 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((TCP_WND / 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 <= 0xffff", new_rcv_ann_wnd <= 0xffff);
+ pcb->rcv_ann_wnd = (u16_t)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, u16_t len)
+{
+ int wnd_inflation;
+
+ LWIP_ASSERT("tcp_recved: len would wrap rcv_wnd\n",
+ len <= 0xffff - pcb->rcv_wnd );
+
+ pcb->rcv_wnd += len;
+ if (pcb->rcv_wnd > TCP_WND) {
+ pcb->rcv_wnd = TCP_WND;
+ }
+
+ 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 - pcb->rcv_wnd));
+}
+
+/**
+ * A nastly hack featuring 'goto' statements that allocates a
+ * new TCP local port.
+ *
+ * @return a new (free) local TCP port number
+ */
+static u16_t
+tcp_new_port(void)
+{
+ int i;
+ struct tcp_pcb *pcb;
+#ifndef TCP_LOCAL_PORT_RANGE_START
+#define TCP_LOCAL_PORT_RANGE_START 4096
+#define TCP_LOCAL_PORT_RANGE_END 0x7fff
+#endif
+ static u16_t port = TCP_LOCAL_PORT_RANGE_START;
+
+ again:
+ if (++port > TCP_LOCAL_PORT_RANGE_END) {
+ port = TCP_LOCAL_PORT_RANGE_START;
+ }
+ /* Check all PCB lists. */
+ for (i = 1; i < NUM_TCP_PCB_LISTS; i++) {
+ for(pcb = *tcp_pcb_lists[i]; pcb != NULL; pcb = pcb->next) {
+ if (pcb->local_port == port) {
+ goto again;
+ }
+ }
+ }
+ return port;
+}
+
+/**
+ * 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", pcb->state == 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))) {
+ /* no local IP address set, yet. */
+ struct netif *netif = ip_route(&(pcb->remote_ip));
+ if (netif == NULL) {
+ /* Don't even try to send a SYN packet if we have no route
+ since that will fail. */
+ return ERR_RTE;
+ }
+ /* Use the netif's IP address as local address. */
+ ip_addr_copy(pcb->local_ip, netif->ip_addr);
+ }
+
+ if (pcb->local_port == 0) {
+ pcb->local_port = tcp_new_port();
+ }
+#if SO_REUSE
+ if ((pcb->so_options & SOF_REUSEADDR) != 0) {
+ /* Since SOF_REUSEADDR allows reusing a local address, we have to make sure
+ now that the 5-tuple is unique. */
+ struct tcp_pcb *cpcb;
+ int i;
+ /* Don't check listen PCBs, check bound-, active- and TIME-WAIT PCBs. */
+ for (i = 1; i < NUM_TCP_PCB_LISTS; i++) {
+ for(cpcb = *tcp_pcb_lists[i]; cpcb != NULL; cpcb = cpcb->next) {
+ if ((cpcb->local_port == pcb->local_port) &&
+ (cpcb->remote_port == port) &&
+ ip_addr_cmp(&cpcb->local_ip, &pcb->local_ip) &&
+ ip_addr_cmp(&cpcb->remote_ip, ipaddr)) {
+ /* linux returns EISCONN here, but ERR_USE should be OK for us */
+ return ERR_USE;
+ }
+ }
+ }
+ }
+#endif /* SO_REUSE */
+ iss = tcp_next_iss();
+ pcb->rcv_nxt = 0;
+ pcb->snd_nxt = iss;
+ pcb->lastack = iss - 1;
+ pcb->snd_lbb = iss - 1;
+ pcb->rcv_wnd = TCP_WND;
+ pcb->rcv_ann_wnd = TCP_WND;
+ pcb->rcv_ann_right_edge = pcb->rcv_nxt;
+ pcb->snd_wnd = TCP_WND;
+ /* As initial send MSS, we use TCP_MSS but limit it to 536.
+ The send MSS is updated when an MSS option is received. */
+ pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
+#if TCP_CALCULATE_EFF_SEND_MSS
+ pcb->mss = tcp_eff_send_mss(pcb->mss, ipaddr);
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+ pcb->cwnd = 1;
+ pcb->ssthresh = pcb->mss * 10;
+#if LWIP_CALLBACK_API
+ pcb->connected = connected;
+#else /* LWIP_CALLBACK_API */
+ LWIP_UNUSED_ARG(connected);
+#endif /* LWIP_CALLBACK_API */
+
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect: tcp_ticks=%"U32_F" iss=%"U32_F"\n", tcp_ticks, iss));
+
+ /* 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 */
+ pcb->state = SYN_SENT;
+ TCP_RMV(&tcp_bound_pcbs, pcb);
+ TCP_REG(&tcp_active_pcbs, pcb);
+ snmp_inc_tcpactiveopens();
+
+ tcp_output(pcb);
+ }
+ return ret;
+}
+
+/**
+ * Called every 500 ms and implements the retransmission timer and the timer that
+ * removes PCBs that have been in TIME-WAIT for enough time. It also increments
+ * various timers such as the inactivity timer in each PCB.
+ *
+ * Automatically called from tcp_tmr().
+ */
+void
+tcp_slowtmr(void)
+{
+ struct tcp_pcb *pcb, *pcb2, *prev;
+ u16_t eff_wnd;
+ 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;
+
+ tcp_debug_print_pcbs(); //DG
+
+ err = ERR_OK;
+
+ ++tcp_ticks;
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: tcp_ticks=%"U32_F"\n", tcp_ticks));
+
+ /* Steps through all of the active PCBs. */
+ prev = NULL;
+ pcb = tcp_active_pcbs;
+ if (pcb == NULL) {
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
+ }
+ while (pcb != NULL) {
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
+ LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED);
+ LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN);
+ LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT);
+
+ pcb_remove = 0;
+ pcb_reset = 0;
+
+ if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
+ ++pcb_remove;
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
+ }
+ else if (pcb->nrtx == TCP_MAXRTX) {
+ ++pcb_remove;
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
+ } else {
+ if (pcb->persist_backoff > 0) {
+ /* If snd_wnd is zero, 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++;
+ }
+ tcp_zero_window_probe(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 (pcb->state != SYN_SENT) {
+ pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
+ }
+
+ /* Reset the retransmission timer. */
+ pcb->rtime = 0;
+
+ /* Reduce congestion window and ssthresh. */
+ eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
+ pcb->ssthresh = eff_wnd >> 1;
+ if (pcb->ssthresh < (pcb->mss << 1)) {
+ pcb->ssthresh = (pcb->mss << 1);
+ }
+ pcb->cwnd = pcb->mss;
+ 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 (pcb->state == FIN_WAIT_2) {
+ if ((u32_t)(tcp_ticks - pcb->tmr) >
+ TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
+ ++pcb_remove;
+ 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) &&
+ ((pcb->state == ESTABLISHED) ||
+ (pcb->state == CLOSE_WAIT))) {
+#if LWIP_TCP_KEEPALIVE
+ if((u32_t)(tcp_ticks - pcb->tmr) >
+ (pcb->keep_idle + (pcb->keep_cnt*pcb->keep_intvl))
+ / TCP_SLOW_INTERVAL)
+#else
+ if((u32_t)(tcp_ticks - pcb->tmr) >
+ (pcb->keep_idle + TCP_MAXIDLE) / TCP_SLOW_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;
+ ++pcb_reset;
+ }
+#if LWIP_TCP_KEEPALIVE
+ else if((u32_t)(tcp_ticks - pcb->tmr) >
+ (pcb->keep_idle + pcb->keep_cnt_sent * pcb->keep_intvl)
+ / TCP_SLOW_INTERVAL)
+#else
+ else if((u32_t)(tcp_ticks - pcb->tmr) >
+ (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEPINTVL_DEFAULT)
+ / TCP_SLOW_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->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 (pcb->state == SYN_RCVD) {
+ if ((u32_t)(tcp_ticks - pcb->tmr) >
+ TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) {
+ ++pcb_remove;
+ 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 (pcb->state == LAST_ACK) {
+ if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
+ ++pcb_remove;
+ 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);
+ /* Remove PCB from tcp_active_pcbs list. */
+ if (prev != NULL) {
+ LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
+ prev->next = pcb->next;
+ } else {
+ /* This PCB was the first. */
+ LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb);
+ tcp_active_pcbs = pcb->next;
+ }
+
+ TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
+ if (pcb_reset) {
+ tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip,
+ pcb->local_port, pcb->remote_port);
+ }
+
+ pcb2 = pcb->next;
+ memp_free(MEMP_TCP_PCB, pcb);
+ pcb = pcb2;
+ } else {
+ /* get the 'next' element now and work with 'prev' below (in case of abort) */
+ prev = pcb;
+ pcb = pcb->next;
+
+ /* We check if we should poll the connection. */
+ ++prev->polltmr;
+ if (prev->polltmr >= prev->pollinterval) {
+ prev->polltmr = 0;
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
+ TCP_EVENT_POLL(prev, err);
+ /* if err == ERR_ABRT, 'prev' is already deallocated */
+ if (err == ERR_OK) {
+ tcp_output(prev);
+ }
+ }
+ }
+ }
+
+
+ /* Steps through all of the TIME-WAIT PCBs. */
+ prev = NULL;
+ pcb = tcp_tw_pcbs;
+ while (pcb != NULL) {
+ LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == 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 / TCP_SLOW_INTERVAL) {
+ ++pcb_remove;
+ }
+
+
+
+ /* If the PCB should be removed, do it. */
+ if (pcb_remove) {
+ tcp_pcb_purge(pcb);
+ /* Remove PCB from tcp_tw_pcbs list. */
+ if (prev != NULL) {
+ LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
+ prev->next = pcb->next;
+ } else {
+ /* This PCB was the first. */
+ LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb);
+ tcp_tw_pcbs = pcb->next;
+ }
+ pcb2 = pcb->next;
+ memp_free(MEMP_TCP_PCB, pcb);
+ pcb = pcb2;
+ } else {
+ prev = pcb;
+ pcb = pcb->next;
+ }
+ }
+}
+
+/**
+ * Is called every TCP_FAST_INTERVAL (250 ms) and process data previously
+ * "refused" by upper layer (application) and sends delayed ACKs.
+ *
+ * Automatically called from tcp_tmr().
+ */
+void
+tcp_fasttmr(void)
+{
+ struct tcp_pcb *pcb = tcp_active_pcbs;
+
+ while(pcb != NULL) {
+ struct tcp_pcb *next = pcb->next;
+ /* If there is data which was previously "refused" by upper layer */
+ if (pcb->refused_data != NULL) {
+ /* Notify again application with data previously received. */
+ err_t err;
+ 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 = NULL;
+ } else if (err == ERR_ABRT) {
+ /* if err == ERR_ABRT, 'pcb' is already deallocated */
+ pcb = NULL;
+ }
+ }
+
+ /* 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);
+ }
+
+ pcb = next;
+ }
+}
+
+/**
+ * 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_seg *seg)
+{
+ while (seg != NULL) {
+ struct tcp_seg *next = seg->next;
+ tcp_seg_free(seg);
+ seg = next;
+ }
+}
+
+/**
+ * Frees a TCP segment (tcp_seg structure).
+ *
+ * @param seg single tcp_seg to free
+ */
+void
+tcp_seg_free(struct tcp_seg *seg)
+{
+ if (seg != NULL) {
+ if (seg->p != NULL) {
+ pbuf_free(seg->p);
+#if TCP_DEBUG
+ seg->p = NULL;
+#endif /* TCP_DEBUG */
+ }
+ memp_free(MEMP_TCP_SEG, seg);
+ }
+}
+
+/**
+ * Sets the priority of a connection.
+ *
+ * @param pcb the tcp_pcb to manipulate
+ * @param prio new priority
+ */
+void
+tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
+{
+ pcb->prio = prio;
+}
+
+#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_seg *seg)
+{
+ struct tcp_seg *cseg;
+
+ cseg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG);
+ 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, p->tot_len);
+ pbuf_free(p);
+ } else if (err == ERR_OK) {
+ return tcp_close(pcb);
+ }
+ return ERR_OK;
+}
+#endif /* LWIP_CALLBACK_API */
+
+/**
+ * Kills the oldest active connection that has lower priority than prio.
+ *
+ * @param prio minimum priority
+ */
+static void
+tcp_kill_prio(u8_t prio)
+{
+ struct tcp_pcb *pcb, *inactive;
+ u32_t inactivity;
+ u8_t mprio;
+
+
+ mprio = TCP_PRIO_MAX;
+
+ /* We kill the oldest active connection that has lower priority than prio. */
+ inactivity = 0;
+ inactive = NULL;
+ for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+ if (pcb->prio <= prio &&
+ pcb->prio <= mprio &&
+ (u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
+ inactivity = tcp_ticks - pcb->tmr;
+ inactive = pcb;
+ mprio = pcb->prio;
+ }
+ }
+ if (inactive != NULL) {
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
+ (void *)inactive, inactivity));
+ tcp_abort(inactive);
+ }
+}
+
+/**
+ * Kills the oldest connection that is in TIME_WAIT state.
+ * Called from tcp_alloc() if no more connections are available.
+ */
+static void
+tcp_kill_timewait(void)
+{
+ struct tcp_pcb *pcb, *inactive;
+ u32_t inactivity;
+
+ inactivity = 0;
+ inactive = NULL;
+ /* Go through the list of TIME_WAIT pcbs and get the oldest pcb. */
+ for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+ if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
+ inactivity = tcp_ticks - pcb->tmr;
+ inactive = pcb;
+ }
+ }
+ if (inactive != NULL) {
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n",
+ (void *)inactive, inactivity));
+ tcp_abort(inactive);
+ }
+}
+
+/**
+ * Allocate a new tcp_pcb structure.
+ *
+ * @param prio priority for the new pcb
+ * @return a new tcp_pcb that initially is in state CLOSED
+ */
+struct tcp_pcb *
+tcp_alloc(u8_t prio)
+{
+ struct tcp_pcb *pcb;
+ u32_t iss;
+
+ pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+ if (pcb == NULL) {
+ /* Try killing oldest connection in TIME-WAIT. */
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
+ tcp_kill_timewait();
+ /* Try to allocate a tcp_pcb again. */
+ pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+ if (pcb == NULL) {
+ /* Try killing active connections with lower priority than the new one. */
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing connection with prio lower than %d\n", prio));
+ tcp_kill_prio(prio);
+ /* Try to allocate a tcp_pcb again. */
+ pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+ if (pcb != NULL) {
+ /* adjust err stats: memp_malloc failed twice before */
+ MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+ }
+ }
+ if (pcb != NULL) {
+ /* adjust err stats: timewait PCB was freed above */
+ MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+ }
+ }
+ if (pcb != NULL) {
+ memset(pcb, 0, sizeof(struct tcp_pcb));
+ pcb->prio = prio;
+ pcb->snd_buf = TCP_SND_BUF;
+ pcb->snd_queuelen = 0;
+ pcb->rcv_wnd = TCP_WND;
+ pcb->rcv_ann_wnd = TCP_WND;
+ 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. */
+ pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
+ pcb->rto = 3000 / TCP_SLOW_INTERVAL;
+ pcb->sa = 0;
+ pcb->sv = 3000 / TCP_SLOW_INTERVAL;
+ pcb->rtime = -1;
+ 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;
+
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: tcp_ticks=%"U32_F" iss=%"U32_F"\n", tcp_ticks, iss));
+
+ pcb->polltmr = 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;
+ }
+ return pcb;
+}
+
+/**
+ * Creates a new TCP protocol control block but doesn't place it on
+ * any of the TCP PCB lists.
+ * The pcb is not put on any list until binding using tcp_bind().
+ *
+ * @internal: Maybe there should be a idle TCP PCB list where these
+ * PCBs are put on. Port reservation using tcp_bind() is implemented but
+ * allocated pcbs that are not bound can't be killed automatically if wanting
+ * to allocate a pcb with higher prio (@see tcp_kill_prio())
+ *
+ * @return a new tcp_pcb that initially is in state CLOSED
+ */
+struct tcp_pcb *
+tcp_new(void)
+{
+ return tcp_alloc(TCP_PRIO_NORMAL);
+}
+
+/**
+ * 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;
+}
+#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 (pcb->state != CLOSED &&
+ pcb->state != TIME_WAIT &&
+ pcb->state != LISTEN) {
+
+ LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
+
+#if TCP_LISTEN_BACKLOG
+ if (pcb->state == SYN_RCVD) {
+ /* Need to find the corresponding listen_pcb and decrease its accepts_pending */
+ struct tcp_pcb_listen *lpcb;
+ LWIP_ASSERT("tcp_pcb_purge: pcb->state == SYN_RCVD but tcp_listen_pcbs is NULL",
+ tcp_listen_pcbs.listen_pcbs != NULL);
+ for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
+ if ((lpcb->local_port == pcb->local_port) &&
+ (ip_addr_isany(&lpcb->local_ip) ||
+ ip_addr_cmp(&pcb->local_ip, &lpcb->local_ip))) {
+ /* port and address of the listen pcb match the timed-out pcb */
+ LWIP_ASSERT("tcp_pcb_purge: listen pcb does not have accepts pending",
+ lpcb->accepts_pending > 0);
+ lpcb->accepts_pending--;
+ break;
+ }
+ }
+ }
+#endif /* TCP_LISTEN_BACKLOG */
+
+
+ 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->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_segs_free(pcb->unsent);
+ tcp_segs_free(pcb->unacked);
+ pcb->unacked = pcb->unsent = NULL;
+#if TCP_OVERSIZE
+ pcb->unsent_oversize = 0;
+#endif /* TCP_OVERSIZE */
+ }
+}
+
+/**
+ * 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 **pcblist, struct tcp_pcb *pcb)
+{
+ TCP_RMV(pcblist, pcb);
+
+ tcp_pcb_purge(pcb);
+
+ /* if there is an outstanding delayed ACKs, send it */
+ if (pcb->state != TIME_WAIT &&
+ pcb->state != LISTEN &&
+ pcb->flags & TF_ACK_DELAY) {
+ pcb->flags |= TF_ACK_NOW;
+ tcp_output(pcb);
+ }
+
+ if (pcb->state != 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 */
+ }
+
+ pcb->state = 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 determin 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, ip_addr_t *addr)
+{
+ u16_t mss_s;
+ struct netif *outif;
+
+ outif = ip_route(addr);
+ if ((outif != NULL) && (outif->mtu != 0)) {
+ mss_s = outif->mtu - IP_HLEN - TCP_HLEN;
+ /* RFC 1122, chap 4.2.2.6:
+ * Eff.snd.MSS = min(SendMSS+20, MMS_S) - TCPhdrsize - IPoptionsize
+ * We correct for TCP options in tcp_write(), and don't support IP options.
+ */
+ sendmss = LWIP_MIN(sendmss, mss_s);
+ }
+ return sendmss;
+}
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+
+const char*
+tcp_debug_state_str(enum tcp_state s)
+{
+ return tcp_state_str[s];
+}
+
+#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_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)
+{
+ struct tcp_pcb *pcb;
+ LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n"));
+ for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+ LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
+ pcb->local_port, pcb->remote_port,
+ pcb->snd_nxt, pcb->rcv_nxt));
+ tcp_debug_print_state(pcb->state);
+ }
+ LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n"));
+ for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
+ LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
+ pcb->local_port, pcb->remote_port,
+ pcb->snd_nxt, pcb->rcv_nxt));
+ tcp_debug_print_state(pcb->state);
+ }
+ LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n"));
+ for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+ LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
+ pcb->local_port, pcb->remote_port,
+ pcb->snd_nxt, pcb->rcv_nxt));
+ tcp_debug_print_state(pcb->state);
+ }
+}
+
+/**
+ * Check state consistency of the tcp_pcb lists.
+ */
+s16_t
+tcp_pcbs_sane(void)
+{
+ struct tcp_pcb *pcb;
+ for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+ LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED);
+ LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN);
+ LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
+ }
+ for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+ LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
+ }
+ return 1;
+}
+#endif /* TCP_DEBUG */
+
+#endif /* LWIP_TCP */