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tcp.c
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/**
* @file
* Transmission Control Protocol for IP
* See also @ref tcp_raw
*
* @defgroup tcp_raw TCP
* @ingroup callbackstyle_api
* Transmission Control Protocol for IP\n
* @see @ref api
*
* Common functions for the TCP implementation, such as functions
* 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.\n
*
* TCP connection setup
* --------------------
* The functions used for setting up connections is similar to that of
* the sequential API and of the BSD socket API. A new TCP connection
* identifier (i.e., a protocol control block - PCB) is created with the
* tcp_new() function. This PCB can then be either set to listen for new
* incoming connections or be explicitly connected to another host.
* - tcp_new()
* - tcp_bind()
* - tcp_listen() and tcp_listen_with_backlog()
* - tcp_accept()
* - tcp_connect()
*
* Sending TCP data
* ----------------
* TCP data is sent by enqueueing the data with a call to tcp_write() and
* triggering to send by calling tcp_output(). When the data is successfully
* transmitted to the remote host, the application will be notified with a
* call to a specified callback function.
* - tcp_write()
* - tcp_output()
* - tcp_sent()
*
* Receiving TCP data
* ------------------
* TCP data reception is callback based - an application specified
* callback function is called when new data arrives. When the
* application has taken the data, it has to call the tcp_recved()
* function to indicate that TCP can advertise increase the receive
* window.
* - tcp_recv()
* - tcp_recved()
*
* Application polling
* -------------------
* When a connection is idle (i.e., no data is either transmitted or
* received), lwIP will repeatedly poll the application by calling a
* specified callback function. This can be used either as a watchdog
* timer for killing connections that have stayed idle for too long, or
* as a method of waiting for memory to become available. For instance,
* if a call to tcp_write() has failed because memory wasn't available,
* the application may use the polling functionality to call tcp_write()
* again when the connection has been idle for a while.
* - tcp_poll()
*
* Closing and aborting connections
* --------------------------------
* - tcp_close()
* - tcp_abort()
* - tcp_err()
*
*/
/*
* 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 <[email protected]>
*
*/
#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/tcp.h"
#include "lwip/priv/tcp_priv.h"
#include "lwip/debug.h"
#include "lwip/stats.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"
#include "lwip/nd6.h"
#include <string.h>
#ifdef LWIP_HOOK_FILENAME
#include LWIP_HOOK_FILENAME
#endif
#ifndef TCP_LOCAL_PORT_RANGE_START
/* From http://www.iana.org/assignments/port-numbers:
"The Dynamic and/or Private Ports are those from 49152 through 65535" */
#define TCP_LOCAL_PORT_RANGE_START 0xc000
#define TCP_LOCAL_PORT_RANGE_END 0xffff
#define TCP_ENSURE_LOCAL_PORT_RANGE(port) ((u16_t)(((port) & (u16_t)~TCP_LOCAL_PORT_RANGE_START) + TCP_LOCAL_PORT_RANGE_START))
#endif
#if LWIP_TCP_KEEPALIVE
#define TCP_KEEP_DUR(pcb) ((pcb)->keep_cnt * (pcb)->keep_intvl)
#define TCP_KEEP_INTVL(pcb) ((pcb)->keep_intvl)
#else /* LWIP_TCP_KEEPALIVE */
#define TCP_KEEP_DUR(pcb) TCP_MAXIDLE
#define TCP_KEEP_INTVL(pcb) TCP_KEEPINTVL_DEFAULT
#endif /* LWIP_TCP_KEEPALIVE */
/* As initial send MSS, we use TCP_MSS but limit it to 536. */
#if TCP_MSS > 536
#define INITIAL_MSS 536
#else
#define INITIAL_MSS TCP_MSS
#endif
static 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"
};
/* last local TCP port */
static u16_t tcp_port = TCP_LOCAL_PORT_RANGE_START;
/* Incremented every coarse grained timer shot (typically every 500 ms). */
u32_t tcp_ticks;
static const u8_t tcp_backoff[13] =
{ 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
/* Times per slowtmr hits */
static 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;
/** An array with all (non-temporary) PCB lists, mainly used for smaller code size */
struct tcp_pcb **const tcp_pcb_lists[] = {&tcp_listen_pcbs.pcbs, &tcp_bound_pcbs,
&tcp_active_pcbs, &tcp_tw_pcbs
};
u8_t tcp_active_pcbs_changed;
/** Timer counter to handle calling slow-timer from tcp_tmr() */
static u8_t tcp_timer;
static u8_t tcp_timer_ctr;
static u16_t tcp_new_port(void);
static err_t tcp_close_shutdown_fin(struct tcp_pcb *pcb);
#if LWIP_TCP_PCB_NUM_EXT_ARGS
static void tcp_ext_arg_invoke_callbacks_destroyed(struct tcp_pcb_ext_args *ext_args);
#endif
/**
* Initialize this module.
*/
void
tcp_init(void)
{
#ifdef LWIP_RAND
tcp_port = TCP_ENSURE_LOCAL_PORT_RANGE(LWIP_RAND());
#endif /* LWIP_RAND */
}
/** Free a tcp pcb */
void
tcp_free(struct tcp_pcb *pcb)
{
LWIP_ASSERT("tcp_free: LISTEN", pcb->state != LISTEN);
#if LWIP_TCP_PCB_NUM_EXT_ARGS
tcp_ext_arg_invoke_callbacks_destroyed(pcb->ext_args);
#endif
memp_free(MEMP_TCP_PCB, pcb);
}
/** Free a tcp listen pcb */
static void
tcp_free_listen(struct tcp_pcb *pcb)
{
LWIP_ASSERT("tcp_free_listen: !LISTEN", pcb->state != LISTEN);
#if LWIP_TCP_PCB_NUM_EXT_ARGS
tcp_ext_arg_invoke_callbacks_destroyed(pcb->ext_args);
#endif
memp_free(MEMP_TCP_PCB_LISTEN, pcb);
}
/**
* Called periodically to dispatch TCP timers.
*/
void
tcp_tmr(void)
{
/* Call tcp_fasttmr() every 250 ms */
tcp_fasttmr();
if (++tcp_timer & 1) {
/* Call tcp_slowtmr() every 500 ms, i.e., every other timer
tcp_tmr() is called. */
tcp_slowtmr();
}
}
#if LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG
/** Called when a listen pcb is closed. Iterates one pcb list and removes the
* closed listener pcb from pcb->listener if matching.
*/
static void
tcp_remove_listener(struct tcp_pcb *list, struct tcp_pcb_listen *lpcb)
{
struct tcp_pcb *pcb;
LWIP_ASSERT("tcp_remove_listener: invalid listener", lpcb != NULL);
for (pcb = list; pcb != NULL; pcb = pcb->next) {
if (pcb->listener == lpcb) {
pcb->listener = NULL;
}
}
}
#endif
/** Called when a listen pcb is closed. Iterates all pcb lists and removes the
* closed listener pcb from pcb->listener if matching.
*/
static void
tcp_listen_closed(struct tcp_pcb *pcb)
{
#if LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG
size_t i;
LWIP_ASSERT("pcb != NULL", pcb != NULL);
LWIP_ASSERT("pcb->state == LISTEN", pcb->state == LISTEN);
for (i = 1; i < LWIP_ARRAYSIZE(tcp_pcb_lists); i++) {
tcp_remove_listener(*tcp_pcb_lists[i], (struct tcp_pcb_listen *)pcb);
}
#endif
LWIP_UNUSED_ARG(pcb);
}
#if TCP_LISTEN_BACKLOG
/** @ingroup tcp_raw
* Delay accepting a connection in respect to the listen backlog:
* the number of outstanding connections is increased until
* tcp_backlog_accepted() is called.
*
* ATTENTION: the caller is responsible for calling tcp_backlog_accepted()
* or else the backlog feature will get out of sync!
*
* @param pcb the connection pcb which is not fully accepted yet
*/
void
tcp_backlog_delayed(struct tcp_pcb *pcb)
{
LWIP_ASSERT("pcb != NULL", pcb != NULL);
LWIP_ASSERT_CORE_LOCKED();
if ((pcb->flags & TF_BACKLOGPEND) == 0) {
if (pcb->listener != NULL) {
pcb->listener->accepts_pending++;
LWIP_ASSERT("accepts_pending != 0", pcb->listener->accepts_pending != 0);
tcp_set_flags(pcb, TF_BACKLOGPEND);
}
}
}
/** @ingroup tcp_raw
* A delayed-accept a connection is accepted (or closed/aborted): decreases
* the number of outstanding connections after calling tcp_backlog_delayed().
*
* ATTENTION: the caller is responsible for calling tcp_backlog_accepted()
* or else the backlog feature will get out of sync!
*
* @param pcb the connection pcb which is now fully accepted (or closed/aborted)
*/
void
tcp_backlog_accepted(struct tcp_pcb *pcb)
{
LWIP_ASSERT("pcb != NULL", pcb != NULL);
LWIP_ASSERT_CORE_LOCKED();
if ((pcb->flags & TF_BACKLOGPEND) != 0) {
if (pcb->listener != NULL) {
LWIP_ASSERT("accepts_pending != 0", pcb->listener->accepts_pending != 0);
pcb->listener->accepts_pending--;
tcp_clear_flags(pcb, TF_BACKLOGPEND);
}
}
}
#endif /* TCP_LISTEN_BACKLOG */
/**
* 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)
{
LWIP_ASSERT("tcp_close_shutdown: invalid pcb", pcb != NULL);
if (rst_on_unacked_data && ((pcb->state == ESTABLISHED) || (pcb->state == CLOSE_WAIT))) {
if ((pcb->refused_data != NULL) || (pcb->rcv_wnd != TCP_WND_MAX(pcb))) {
/* 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, pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip,
pcb->local_port, pcb->remote_port);
tcp_pcb_purge(pcb);
TCP_RMV_ACTIVE(pcb);
/* Deallocate the pcb since we already sent a RST for it */
if (tcp_input_pcb == pcb) {
/* prevent using a deallocated pcb: free it from tcp_input later */
tcp_trigger_input_pcb_close();
} else {
tcp_free(pcb);
}
return ERR_OK;
}
}
/* - states which free the pcb are handled here,
- states which send FIN and change state are handled in tcp_close_shutdown_fin() */
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. */
if (pcb->local_port != 0) {
TCP_RMV(&tcp_bound_pcbs, pcb);
}
tcp_free(pcb);
break;
case LISTEN:
tcp_listen_closed(pcb);
tcp_pcb_remove(&tcp_listen_pcbs.pcbs, pcb);
tcp_free_listen(pcb);
break;
case SYN_SENT:
TCP_PCB_REMOVE_ACTIVE(pcb);
tcp_free(pcb);
MIB2_STATS_INC(mib2.tcpattemptfails);
break;
default:
return tcp_close_shutdown_fin(pcb);
}
return ERR_OK;
}
static err_t
tcp_close_shutdown_fin(struct tcp_pcb *pcb)
{
err_t err;
LWIP_ASSERT("pcb != NULL", pcb != NULL);
switch (pcb->state) {
case SYN_RCVD:
err = tcp_send_fin(pcb);
if (err == ERR_OK) {
tcp_backlog_accepted(pcb);
MIB2_STATS_INC(mib2.tcpattemptfails);
pcb->state = FIN_WAIT_1;
}
break;
case ESTABLISHED:
err = tcp_send_fin(pcb);
if (err == ERR_OK) {
MIB2_STATS_INC(mib2.tcpestabresets);
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_fin(pcb);
if (err == ERR_OK) {
MIB2_STATS_INC(mib2.tcpestabresets);
pcb->state = LAST_ACK;
}
break;
default:
/* Has already been closed, do nothing. */
return ERR_OK;
}
if (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. */
tcp_output(pcb);
} else if (err == ERR_MEM) {
/* Mark this pcb for closing. Closing is retried from tcp_tmr. */
tcp_set_flags(pcb, TF_CLOSEPEND);
/* We have to return ERR_OK from here to indicate to the callers that this
pcb should not be used any more as it will be freed soon via tcp_tmr.
This is OK here since sending FIN does not guarantee a time frime for
actually freeing the pcb, either (it is left in closure states for
remote ACK or timeout) */
return ERR_OK;
}
return err;
}
/**
* @ingroup tcp_raw
* 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).
*
* The function may return ERR_MEM if no memory
* was available for closing the connection. If so, the application
* should wait and try again either by using the acknowledgment
* callback or the polling functionality. If the close succeeds, the
* function returns ERR_OK.
*
* @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)
{
LWIP_ASSERT_CORE_LOCKED();
LWIP_ERROR("tcp_close: invalid pcb", pcb != NULL, return ERR_ARG);
LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
tcp_debug_print_state(pcb->state);
if (pcb->state != LISTEN) {
/* Set a flag not to receive any more data... */
tcp_set_flags(pcb, TF_RXCLOSED);
}
/* ... and close */
return tcp_close_shutdown(pcb, 1);
}
/**
* @ingroup tcp_raw
* Causes all or part of a full-duplex connection of this PCB to be shut down.
* This doesn't deallocate the PCB unless shutting down both sides!
* Shutting down both sides is the same as calling tcp_close, so if it succeds
* (i.e. returns ER_OK), the PCB must not be referenced any more!
*
* @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)
{
LWIP_ASSERT_CORE_LOCKED();
LWIP_ERROR("tcp_shutdown: invalid pcb", pcb != NULL, return ERR_ARG);
if (pcb->state == LISTEN) {
return ERR_CONN;
}
if (shut_rx) {
/* shut down the receive side: set a flag not to receive any more data... */
tcp_set_flags(pcb, 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 (pcb->state) {
case SYN_RCVD:
case ESTABLISHED:
case CLOSE_WAIT:
return tcp_close_shutdown(pcb, (u8_t)shut_rx);
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;
}
}
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;
#if LWIP_CALLBACK_API
tcp_err_fn errf;
#endif /* LWIP_CALLBACK_API */
void *errf_arg;
LWIP_ASSERT_CORE_LOCKED();
LWIP_ERROR("tcp_abandon: invalid pcb", pcb != NULL, return);
/* 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);
tcp_free(pcb);
} else {
int send_rst = 0;
u16_t local_port = 0;
enum tcp_state last_state;
seqno = pcb->snd_nxt;
ackno = pcb->rcv_nxt;
#if LWIP_CALLBACK_API
errf = pcb->errf;
#endif /* LWIP_CALLBACK_API */
errf_arg = pcb->callback_arg;
if (pcb->state == CLOSED) {
if (pcb->local_port != 0) {
/* bound, not yet opened */
TCP_RMV(&tcp_bound_pcbs, pcb);
}
} else {
send_rst = reset;
local_port = pcb->local_port;
TCP_PCB_REMOVE_ACTIVE(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 */
tcp_backlog_accepted(pcb);
if (send_rst) {
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
tcp_rst(pcb, seqno, ackno, &pcb->local_ip, &pcb->remote_ip, local_port, pcb->remote_port);
}
last_state = pcb->state;
tcp_free(pcb);
TCP_EVENT_ERR(last_state, errf, errf_arg, ERR_ABRT);
}
}
/**
* @ingroup tcp_raw
* 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);
}
/**
* @ingroup tcp_raw
* Binds the connection to a local port number and IP address. If the
* IP address is not given (i.e., ipaddr == IP_ANY_TYPE), the connection is
* bound to all local IP addresses.
* If another connection is bound to the same port, the function will
* return ERR_USE, otherwise ERR_OK is returned.
* @see MEMP_NUM_TCP_PCB_LISTEN and MEMP_NUM_TCP_PCB
*
* @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 IPx_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_VAL if bind failed because the PCB is not in a valid state
* ERR_OK if bound
*/
err_t
tcp_bind(struct tcp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port)
{
int i;
int max_pcb_list = NUM_TCP_PCB_LISTS;
struct tcp_pcb *cpcb;
#if LWIP_IPV6 && LWIP_IPV6_SCOPES
ip_addr_t zoned_ipaddr;
#endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
LWIP_ASSERT_CORE_LOCKED();
#if LWIP_IPV4
/* Don't propagate NULL pointer (IPv4 ANY) to subsequent functions */
if (ipaddr == NULL) {
ipaddr = IP4_ADDR_ANY;
}
#else /* LWIP_IPV4 */
LWIP_ERROR("tcp_bind: invalid ipaddr", ipaddr != NULL, return ERR_ARG);
#endif /* LWIP_IPV4 */
LWIP_ERROR("tcp_bind: invalid pcb", pcb != NULL, return ERR_ARG);
LWIP_ERROR("tcp_bind: can only bind in state CLOSED", pcb->state == CLOSED, return ERR_VAL);
#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 (ip_get_option(pcb, SOF_REUSEADDR)) {
max_pcb_list = NUM_TCP_PCB_LISTS_NO_TIME_WAIT;
}
#endif /* SO_REUSE */
#if LWIP_IPV6 && LWIP_IPV6_SCOPES
/* If the given IP address should have a zone but doesn't, assign one now.
* This is legacy support: scope-aware callers should always provide properly
* zoned source addresses. Do the zone selection before the address-in-use
* check below; as such we have to make a temporary copy of the address. */
if (IP_IS_V6(ipaddr) && ip6_addr_lacks_zone(ip_2_ip6(ipaddr), IP6_UNICAST)) {
ip_addr_copy(zoned_ipaddr, *ipaddr);
ip6_addr_select_zone(ip_2_ip6(&zoned_ipaddr), ip_2_ip6(&zoned_ipaddr));
ipaddr = &zoned_ipaddr;
}
#endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
if (port == 0) {
port = tcp_new_port();
if (port == 0) {
return ERR_BUF;
}
} else {
/* 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 (!ip_get_option(pcb, SOF_REUSEADDR) ||
!ip_get_option(cpcb, SOF_REUSEADDR))
#endif /* SO_REUSE */
{
/* @todo: check accept_any_ip_version */
if ((IP_IS_V6(ipaddr) == IP_IS_V6_VAL(cpcb->local_ip)) &&
(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)
#if LWIP_IPV4 && LWIP_IPV6
|| (IP_GET_TYPE(ipaddr) != IP_GET_TYPE(&pcb->local_ip))
#endif /* LWIP_IPV4 && LWIP_IPV6 */
) {
ip_addr_set(&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;
}
/**
* @ingroup tcp_raw
* Binds the connection to a netif and IP address.
* After calling this function, all packets received via this PCB
* are guaranteed to have come in via the specified netif, and all
* outgoing packets will go out via the specified netif.
*
* @param pcb the tcp_pcb to bind.
* @param netif the netif to bind to. Can be NULL.
*/
void
tcp_bind_netif(struct tcp_pcb *pcb, const struct netif *netif)
{
LWIP_ASSERT_CORE_LOCKED();
if (netif != NULL) {
pcb->netif_idx = netif_get_index(netif);
} else {
pcb->netif_idx = NETIF_NO_INDEX;
}
}
#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(err);
LWIP_ASSERT("tcp_accept_null: invalid pcb", pcb != NULL);
tcp_abort(pcb);
return ERR_ABRT;
}
#endif /* LWIP_CALLBACK_API */
/**
* @ingroup tcp_raw
* 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.
* When an incoming connection is accepted, the function specified with
* the tcp_accept() function will be called. The pcb has to be bound
* to a local port with the tcp_bind() function.
*
* The tcp_listen() function returns a new connection identifier, and
* the one passed as an argument to the function will be
* deallocated. The reason for this behavior is that less memory is
* needed for a connection that is listening, so tcp_listen() will
* reclaim the memory needed for the original connection and allocate a
* new smaller memory block for the listening connection.
*
* tcp_listen() may return NULL if no memory was available for the
* listening connection. If so, the memory associated with the pcb
* passed as an argument to tcp_listen() will not be deallocated.
*
* The backlog limits the number of outstanding connections
* in the listen queue to the value specified by the backlog argument.
* To use it, your need to set TCP_LISTEN_BACKLOG=1 in your lwipopts.h.
*
* @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_with_backlog(tpcb, backlog);
*/
struct tcp_pcb *
tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog)
{
LWIP_ASSERT_CORE_LOCKED();
return tcp_listen_with_backlog_and_err(pcb, backlog, NULL);
}
/**
* @ingroup tcp_raw
* 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
* @param err when NULL is returned, this contains the error reason
* @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_with_backlog_and_err(tpcb, backlog, &err);
*/
struct tcp_pcb *
tcp_listen_with_backlog_and_err(struct tcp_pcb *pcb, u8_t backlog, err_t *err)
{
struct tcp_pcb_listen *lpcb = NULL;
err_t res;
LWIP_UNUSED_ARG(backlog);
LWIP_ASSERT_CORE_LOCKED();
LWIP_ERROR("tcp_listen_with_backlog_and_err: invalid pcb", pcb != NULL, res = ERR_ARG; goto done);
LWIP_ERROR("tcp_listen_with_backlog_and_err: pcb already connected", pcb->state == CLOSED, res = ERR_CLSD; goto done);
/* already listening? */
if (pcb->state == LISTEN) {
lpcb = (struct tcp_pcb_listen *)pcb;
res = ERR_ALREADY;
goto done;
}
#if SO_REUSE
if (ip_get_option(pcb, SOF_REUSEADDR)) {
/* 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) &&
ip_addr_cmp(&lpcb->local_ip, &pcb->local_ip)) {
/* this address/port is already used */
lpcb = NULL;
res = ERR_USE;
goto done;
}
}
}
#endif /* SO_REUSE */
lpcb = (struct tcp_pcb_listen *)memp_malloc(MEMP_TCP_PCB_LISTEN);
if (lpcb == NULL) {
res = ERR_MEM;
goto done;
}
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->netif_idx = pcb->netif_idx;
lpcb->ttl = pcb->ttl;
lpcb->tos = pcb->tos;
#if LWIP_IPV4 && LWIP_IPV6
IP_SET_TYPE_VAL(lpcb->remote_ip, pcb->local_ip.type);
#endif /* LWIP_IPV4 && LWIP_IPV6 */
ip_addr_copy(lpcb->local_ip, pcb->local_ip);
if (pcb->local_port != 0) {
TCP_RMV(&tcp_bound_pcbs, pcb);
}
#if LWIP_TCP_PCB_NUM_EXT_ARGS
/* copy over ext_args to listening pcb */
memcpy(&lpcb->ext_args, &pcb->ext_args, sizeof(pcb->ext_args));
#endif
tcp_free(pcb);
#if LWIP_CALLBACK_API
lpcb->accept = tcp_accept_null;
#endif /* LWIP_CALLBACK_API */
#if TCP_LISTEN_BACKLOG
lpcb->accepts_pending = 0;
tcp_backlog_set(lpcb, backlog);
#endif /* TCP_LISTEN_BACKLOG */
TCP_REG(&tcp_listen_pcbs.pcbs, (struct tcp_pcb *)lpcb);
res = ERR_OK;
done:
if (err != NULL) {
*err = res;
}
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;
LWIP_ASSERT("tcp_update_rcv_ann_wnd: invalid pcb", pcb != NULL);
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;
#if !LWIP_WND_SCALE
LWIP_ASSERT("new_rcv_ann_wnd <= 0xffff", new_rcv_ann_wnd <= 0xffff);
#endif
pcb->rcv_ann_wnd = (tcpwnd_size_t)new_rcv_ann_wnd;
}
return 0;
}
}
/**
* @ingroup tcp_raw
* 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)
{
u32_t wnd_inflation;
tcpwnd_size_t rcv_wnd;
LWIP_ASSERT_CORE_LOCKED();
LWIP_ERROR("tcp_recved: invalid pcb", pcb != NULL, return);
/* pcb->state LISTEN not allowed here */
LWIP_ASSERT("don't call tcp_recved for listen-pcbs",
pcb->state != LISTEN);
rcv_wnd = (tcpwnd_size_t)(pcb->rcv_wnd + len);
if ((rcv_wnd > TCP_WND_MAX(pcb)) || (rcv_wnd < pcb->rcv_wnd)) {
/* window got too big or tcpwnd_size_t overflow */
LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: window got too big or tcpwnd_size_t overflow\n"));
pcb->rcv_wnd = TCP_WND_MAX(pcb);
} else {
pcb->rcv_wnd = rcv_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);
}