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Diffstat (limited to 'lwip/src/core/tcp.c')
| -rw-r--r-- | lwip/src/core/tcp.c | 2686 |
1 files changed, 2686 insertions, 0 deletions
diff --git a/lwip/src/core/tcp.c b/lwip/src/core/tcp.c new file mode 100644 index 0000000..bd7d64e --- /dev/null +++ b/lwip/src/core/tcp.c @@ -0,0 +1,2686 @@ +/** + * @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 <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/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. + * + * @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 = NETIF_NO_INDEX; + 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); + } + + LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: received %"U16_F" bytes, wnd %"TCPWNDSIZE_F" (%"TCPWNDSIZE_F").\n", + len, pcb->rcv_wnd, (u16_t)(TCP_WND_MAX(pcb) - pcb->rcv_wnd))); +} + +/** + * Allocate a new local TCP port. + * + * @return a new (free) local TCP port number + */ +static u16_t +tcp_new_port(void) +{ + u8_t i; + u16_t n = 0; + struct tcp_pcb *pcb; + +again: + tcp_port++; + if (tcp_port == TCP_LOCAL_PORT_RANGE_END) { + tcp_port = TCP_LOCAL_PORT_RANGE_START; + } + /* Check all PCB lists. */ + for (i = 0; i < NUM_TCP_PCB_LISTS; i++) { + for (pcb = *tcp_pcb_lists[i]; pcb != NULL; pcb = pcb->next) { + if (pcb->local_port == tcp_port) { + n++; + if (n > (TCP_LOCAL_PORT_RANGE_END - TCP_LOCAL_PORT_RANGE_START)) { + return 0; + } + goto again; + } + } + } + return tcp_port; +} + +/** + * @ingroup tcp_raw + * Connects to another host. The function given as the "connected" + * argument will be called when the connection has been established. + * Sets up the pcb to connect to the remote host and sends the + * initial SYN segment which opens the connection. + * + * The tcp_connect() function returns immediately; it does not wait for + * the connection to be properly setup. Instead, it will call the + * function specified as the fourth argument (the "connected" argument) + * when the connection is established. If the connection could not be + * properly established, either because the other host refused the + * connection or because the other host didn't answer, the "err" + * callback function of this pcb (registered with tcp_err, see below) + * will be called. + * + * The tcp_connect() function can return ERR_MEM if no memory is + * available for enqueueing the SYN segment. If the SYN indeed was + * enqueued successfully, the tcp_connect() function returns ERR_OK. + * + * @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 (on error, + the err calback will be called) + * @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, const ip_addr_t *ipaddr, u16_t port, + tcp_connected_fn connected) +{ + struct netif *netif = NULL; + err_t ret; + u32_t iss; + u16_t old_local_port; + + LWIP_ASSERT_CORE_LOCKED(); + + LWIP_ERROR("tcp_connect: invalid pcb", pcb != NULL, return ERR_ARG); + LWIP_ERROR("tcp_connect: invalid ipaddr", ipaddr != NULL, return ERR_ARG); + + LWIP_ERROR("tcp_connect: can only connect from state CLOSED", pcb->state == CLOSED, return ERR_ISCONN); + + LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port)); + ip_addr_set(&pcb->remote_ip, ipaddr); + pcb->remote_port = port; + + if (pcb->netif_idx != NETIF_NO_INDEX) { + netif = netif_get_by_index(pcb->netif_idx); + } else { + /* check if we have a route to the remote host */ + netif = ip_route(&pcb->local_ip, &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; + } + + /* check if local IP has been assigned to pcb, if not, get one */ + if (ip_addr_isany(&pcb->local_ip)) { + const ip_addr_t *local_ip = ip_netif_get_local_ip(netif, ipaddr); + if (local_ip == NULL) { + return ERR_RTE; + } + ip_addr_copy(pcb->local_ip, *local_ip); + } + +#if LWIP_IPV6 && LWIP_IPV6_SCOPES + /* If the given IP address should have a zone but doesn't, assign one now. + * Given that we already have the target netif, this is easy and cheap. */ + if (IP_IS_V6(&pcb->remote_ip) && + ip6_addr_lacks_zone(ip_2_ip6(&pcb->remote_ip), IP6_UNICAST)) { + ip6_addr_assign_zone(ip_2_ip6(&pcb->remote_ip), IP6_UNICAST, netif); + } +#endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */ + + old_local_port = pcb->local_port; + if (pcb->local_port == 0) { + pcb->local_port = tcp_new_port(); + if (pcb->local_port == 0) { + return ERR_BUF; + } + } else { +#if SO_REUSE + if (ip_get_option(pcb, SOF_REUSEADDR)) { + /* 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- and bound-PCBs, check active- and TIME-WAIT PCBs. */ + for (i = 2; 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); + pcb->rcv_nxt = 0; + pcb->snd_nxt = iss; + pcb->lastack = iss - 1; + pcb->snd_wl2 = iss - 1; + pcb->snd_lbb = iss - 1; + /* Start with a window that does not need scaling. When window scaling is + enabled and used, the window is enlarged when both sides agree on scaling. */ + pcb->rcv_wnd = pcb->rcv_ann_wnd = TCPWND_MIN16(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 = INITIAL_MSS; +#if TCP_CALCULATE_EFF_SEND_MSS + pcb->mss = tcp_eff_send_mss_netif(pcb->mss, netif, &pcb->remote_ip); +#endif /* TCP_CALCULATE_EFF_SEND_MSS */ + pcb->cwnd = 1; +#if LWIP_CALLBACK_API + pcb->connected = connected; +#else /* LWIP_CALLBACK_API */ + LWIP_UNUSED_ARG(connected); +#endif /* LWIP_CALLBACK_API */ + + /* 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; + if (old_local_port != 0) { + TCP_RMV(&tcp_bound_pcbs, pcb); + } + TCP_REG_ACTIVE(pcb); + MIB2_STATS_INC(mib2.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, *prev; + tcpwnd_size_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; + + err = ERR_OK; + + ++tcp_ticks; + ++tcp_timer_ctr; + +tcp_slowtmr_start: + /* 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); + if (pcb->last_timer == tcp_timer_ctr) { + /* skip this pcb, we have already processed it */ + prev = pcb; + pcb = pcb->next; + continue; + } + pcb->last_timer = tcp_timer_ctr; + + 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) { + LWIP_ASSERT("tcp_slowtimr: persist ticking with in-flight data", pcb->unacked == NULL); + LWIP_ASSERT("tcp_slowtimr: persist ticking with empty send buffer", pcb->unsent != NULL); + if (pcb->persist_probe >= TCP_MAXRTX) { + ++pcb_remove; /* max probes reached */ + } else { + u8_t backoff_cnt = tcp_persist_backoff[pcb->persist_backoff - 1]; + if (pcb->persist_cnt < backoff_cnt) { + pcb->persist_cnt++; + } + if (pcb->persist_cnt >= backoff_cnt) { + int next_slot = 1; /* increment timer to next slot */ + /* If snd_wnd is zero, send 1 byte probes */ + if (pcb->snd_wnd == 0) { + if (tcp_zero_window_probe(pcb) != ERR_OK) { + next_slot = 0; /* try probe again with current slot */ + } + /* snd_wnd not fully closed, split unsent head and fill window */ + } else { + if (tcp_split_unsent_seg(pcb, (u16_t)pcb->snd_wnd) == ERR_OK) { + if (tcp_output(pcb) == ERR_OK) { + /* sending will cancel persist timer, else retry with current slot */ + next_slot = 0; + } + } + } + if (next_slot) { + pcb->persist_cnt = 0; + if (pcb->persist_backoff < sizeof(tcp_persist_backoff)) { + pcb->persist_backoff++; + } + } + } + } + } else { + /* Increase the retransmission timer if it is running */ + if ((pcb->rtime >= 0) && (pcb->rtime < 0x7FFF)) { + ++pcb->rtime; + } + + if (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)); + /* If prepare phase fails but we have unsent data but no unacked data, + still execute the backoff calculations below, as this means we somehow + failed to send segment. */ + if ((tcp_rexmit_rto_prepare(pcb) == ERR_OK) || ((pcb->unacked == NULL) && (pcb->unsent != NULL))) { + /* Double retransmission time-out unless we are trying to + * connect to somebody (i.e., we are in SYN_SENT). */ + if (pcb->state != SYN_SENT) { + u8_t backoff_idx = LWIP_MIN(pcb->nrtx, sizeof(tcp_backoff) - 1); + int calc_rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[backoff_idx]; + pcb->rto = (s16_t)LWIP_MIN(calc_rto, 0x7FFF); + } + + /* 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 < (tcpwnd_size_t)(pcb->mss << 1)) { + pcb->ssthresh = (tcpwnd_size_t)(pcb->mss << 1); + } + pcb->cwnd = pcb->mss; + LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"TCPWNDSIZE_F + " ssthresh %"TCPWNDSIZE_F"\n", + pcb->cwnd, pcb->ssthresh)); + pcb->bytes_acked = 0; + + /* The following needs to be called AFTER cwnd is set to one + mss - STJ */ + tcp_rexmit_rto_commit(pcb); + } + } + } + } + /* Check if this PCB has stayed too long in FIN-WAIT-2 */ + if (pcb->state == 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 / 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 (ip_get_option(pcb, SOF_KEEPALIVE) && + ((pcb->state == ESTABLISHED) || + (pcb->state == CLOSE_WAIT))) { + if ((u32_t)(tcp_ticks - pcb->tmr) > + (pcb->keep_idle + TCP_KEEP_DUR(pcb)) / TCP_SLOW_INTERVAL) { + LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to ")); + ip_addr_debug_print_val(TCP_DEBUG, pcb->remote_ip); + LWIP_DEBUGF(TCP_DEBUG, ("\n")); + + ++pcb_remove; + ++pcb_reset; + } else if ((u32_t)(tcp_ticks - pcb->tmr) > + (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEP_INTVL(pcb)) + / TCP_SLOW_INTERVAL) { + err = tcp_keepalive(pcb); + if (err == ERR_OK) { + 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 && + (tcp_ticks - pcb->tmr >= (u32_t)pcb->rto * TCP_OOSEQ_TIMEOUT)) { + LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n")); + tcp_free_ooseq(pcb); + } +#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) { + struct tcp_pcb *pcb2; +#if LWIP_CALLBACK_API + tcp_err_fn err_fn = pcb->errf; +#endif /* LWIP_CALLBACK_API */ + void *err_arg; + enum tcp_state last_state; + 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; + } + + if (pcb_reset) { + tcp_rst(pcb, pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip, + pcb->local_port, pcb->remote_port); + } + + err_arg = pcb->callback_arg; + last_state = pcb->state; + pcb2 = pcb; + pcb = pcb->next; + tcp_free(pcb2); + + tcp_active_pcbs_changed = 0; + TCP_EVENT_ERR(last_state, err_fn, err_arg, ERR_ABRT); + if (tcp_active_pcbs_changed) { + goto tcp_slowtmr_start; + } + } 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_active_pcbs_changed = 0; + TCP_EVENT_POLL(prev, err); + if (tcp_active_pcbs_changed) { + goto tcp_slowtmr_start; + } + /* 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) { + struct tcp_pcb *pcb2; + 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; + pcb = pcb->next; + tcp_free(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 or pending FINs. + * + * Automatically called from tcp_tmr(). + */ +void +tcp_fasttmr(void) +{ + struct tcp_pcb *pcb; + + ++tcp_timer_ctr; + +tcp_fasttmr_start: + pcb = tcp_active_pcbs; + + while (pcb != NULL) { + if (pcb->last_timer != tcp_timer_ctr) { + struct tcp_pcb *next; + pcb->last_timer = tcp_timer_ctr; + /* send delayed ACKs */ + if (pcb->flags & TF_ACK_DELAY) { + LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n")); + tcp_ack_now(pcb); + tcp_output(pcb); + tcp_clear_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW); + } + /* send pending FIN */ + if (pcb->flags & TF_CLOSEPEND) { + LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: pending FIN\n")); + tcp_clear_flags(pcb, TF_CLOSEPEND); + tcp_close_shutdown_fin(pcb); + } + + next = pcb->next; + + /* If there is data which was previously "refused" by upper layer */ + if (pcb->refused_data != NULL) { + tcp_active_pcbs_changed = 0; + tcp_process_refused_data(pcb); + if (tcp_active_pcbs_changed) { + /* application callback has changed the pcb list: restart the loop */ + goto tcp_fasttmr_start; + } + } + pcb = next; + } else { + pcb = pcb->next; + } + } +} + +/** Call tcp_output for all active pcbs that have TF_NAGLEMEMERR set */ +void +tcp_txnow(void) +{ + struct tcp_pcb *pcb; + + for (pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { + if (pcb->flags & TF_NAGLEMEMERR) { + tcp_output(pcb); + } + } +} + +/** Pass pcb->refused_data to the recv callback */ +err_t +tcp_process_refused_data(struct tcp_pcb *pcb) +{ +#if TCP_QUEUE_OOSEQ && LWIP_WND_SCALE + struct pbuf *rest; +#endif /* TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ + + LWIP_ERROR("tcp_process_refused_data: invalid pcb", pcb != NULL, return ERR_ARG); + +#if TCP_QUEUE_OOSEQ && LWIP_WND_SCALE + while (pcb->refused_data != NULL) +#endif /* TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ + { + err_t err; + u8_t refused_flags = pcb->refused_data->flags; + /* set pcb->refused_data to NULL in case the callback frees it and then + closes the pcb */ + struct pbuf *refused_data = pcb->refused_data; +#if TCP_QUEUE_OOSEQ && LWIP_WND_SCALE + pbuf_split_64k(refused_data, &rest); + pcb->refused_data = rest; +#else /* TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ + pcb->refused_data = NULL; +#endif /* TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ + /* Notify again application with data previously received. */ + LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n")); + TCP_EVENT_RECV(pcb, refused_data, ERR_OK, err); + if (err == ERR_OK) { + /* did refused_data include a FIN? */ + if ((refused_flags & PBUF_FLAG_TCP_FIN) +#if TCP_QUEUE_OOSEQ && LWIP_WND_SCALE + && (rest == NULL) +#endif /* TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ + ) { + /* correct rcv_wnd as the application won't call tcp_recved() + for the FIN's seqno */ + if (pcb->rcv_wnd != TCP_WND_MAX(pcb)) { + pcb->rcv_wnd++; + } + TCP_EVENT_CLOSED(pcb, err); + if (err == ERR_ABRT) { + return ERR_ABRT; + } + } + } else if (err == ERR_ABRT) { + /* if err == ERR_ABRT, 'pcb' is already deallocated */ + /* Drop incoming packets because pcb is "full" (only if the incoming + segment contains data). */ + LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n")); + return ERR_ABRT; + } else { + /* data is still refused, pbuf is still valid (go on for ACK-only packets) */ +#if TCP_QUEUE_OOSEQ && LWIP_WND_SCALE + if (rest != NULL) { + pbuf_cat(refused_data, rest); + } +#endif /* TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ + pcb->refused_data = refused_data; + return ERR_INPROGRESS; + } + } + return ERR_OK; +} + +/** + * 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); + } +} + +/** + * @ingroup tcp + * 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) +{ + LWIP_ASSERT_CORE_LOCKED(); + + LWIP_ERROR("tcp_setprio: invalid pcb", pcb != NULL, return); + + 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; + + LWIP_ASSERT("tcp_seg_copy: invalid seg", seg != NULL); + + 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); + + LWIP_ERROR("tcp_recv_null: invalid pcb", pcb != NULL, return ERR_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 a 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 = LWIP_MIN(TCP_PRIO_MAX, prio); + + /* We want to kill connections with a lower prio, so bail out if + * supplied prio is 0 - there can never be a lower prio + */ + if (mprio == 0) { + return; + } + + /* We only want kill connections with a lower prio, so decrement prio by one + * and start searching for oldest connection with same or lower priority than mprio. + * We want to find the connections with the lowest possible prio, and among + * these the one with the longest inactivity time. + */ + mprio--; + + inactivity = 0; + inactive = NULL; + for (pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { + /* lower prio is always a kill candidate */ + if ((pcb->prio < mprio) || + /* longer inactivity is also a kill candidate */ + ((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 specific state. + * Called from tcp_alloc() for LAST_ACK and CLOSING if no more connections are available. + */ +static void +tcp_kill_state(enum tcp_state state) +{ + struct tcp_pcb *pcb, *inactive; + u32_t inactivity; + + LWIP_ASSERT("invalid state", (state == CLOSING) || (state == LAST_ACK)); + + inactivity = 0; + inactive = NULL; + /* Go through the list of active pcbs and get the oldest pcb that is in state + CLOSING/LAST_ACK. */ + for (pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { + if (pcb->state == state) { + if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) { + inactivity = tcp_ticks - pcb->tmr; + inactive = pcb; + } + } + } + if (inactive != NULL) { + LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_closing: killing oldest %s PCB %p (%"S32_F")\n", + tcp_state_str[state], (void *)inactive, inactivity)); + /* Don't send a RST, since no data is lost. */ + tcp_abandon(inactive, 0); + } +} + +/** + * 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); + } +} + +/* Called when allocating a pcb fails. + * In this case, we want to handle all pcbs that want to close first: if we can + * now send the FIN (which failed before), the pcb might be in a state that is + * OK for us to now free it. + */ +static void +tcp_handle_closepend(void) +{ + struct tcp_pcb *pcb = tcp_active_pcbs; + + while (pcb != NULL) { + struct tcp_pcb *next = pcb->next; + /* send pending FIN */ + if (pcb->flags & TF_CLOSEPEND) { + LWIP_DEBUGF(TCP_DEBUG, ("tcp_handle_closepend: pending FIN\n")); + tcp_clear_flags(pcb, TF_CLOSEPEND); + tcp_close_shutdown_fin(pcb); + } + pcb = next; + } +} + +/** + * 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; + + LWIP_ASSERT_CORE_LOCKED(); + + pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB); + if (pcb == NULL) { + /* Try to send FIN for all pcbs stuck in TF_CLOSEPEND first */ + tcp_handle_closepend(); + + /* 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 oldest connection in LAST-ACK (these wouldn't go to TIME-WAIT). */ + LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest LAST-ACK connection\n")); + tcp_kill_state(LAST_ACK); + /* Try to allocate a tcp_pcb again. */ + pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB); + if (pcb == NULL) { + /* Try killing oldest connection in CLOSING. */ + LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest CLOSING connection\n")); + tcp_kill_state(CLOSING); + /* Try to allocate a tcp_pcb again. */ + pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB); + if (pcb == NULL) { + /* Try killing oldest active connection with lower priority than the new one. */ + LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest 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 multiple times before */ + MEMP_STATS_DEC(err, MEMP_TCP_PCB); + } + } + if (pcb != NULL) { + /* adjust err stats: memp_malloc failed multiple times before */ + MEMP_STATS_DEC(err, MEMP_TCP_PCB); + } + } + if (pcb != NULL) { + /* adjust err stats: memp_malloc failed multiple times before */ + MEMP_STATS_DEC(err, MEMP_TCP_PCB); + } + } + if (pcb != NULL) { + /* adjust err stats: memp_malloc failed above */ + MEMP_STATS_DEC(err, MEMP_TCP_PCB); + } + } + if (pcb != NULL) { + /* zero out the whole pcb, so there is no need to initialize members to zero */ + memset(pcb, 0, sizeof(struct tcp_pcb)); + pcb->prio = prio; + pcb->snd_buf = TCP_SND_BUF; + /* Start with a window that does not need scaling. When window scaling is + enabled and used, the window is enlarged when both sides agree on scaling. */ + pcb->rcv_wnd = pcb->rcv_ann_wnd = TCPWND_MIN16(TCP_WND); + 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 = INITIAL_MSS; + pcb->rto = 3000 / TCP_SLOW_INTERVAL; + pcb->sv = 3000 / TCP_SLOW_INTERVAL; + pcb->rtime = -1; + pcb->cwnd = 1; + pcb->tmr = tcp_ticks; + pcb->last_timer = tcp_timer_ctr; + + /* RFC 5681 recommends setting ssthresh abritrarily high and gives an example + of using the largest advertised receive window. We've seen complications with + receiving TCPs that use window scaling and/or window auto-tuning where the + initial advertised window is very small and then grows rapidly once the + connection is established. To avoid these complications, we set ssthresh to the + largest effective cwnd (amount of in-flight data) that the sender can have. */ + pcb->ssthresh = TCP_SND_BUF; + +#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 */ + } + return pcb; +} + +/** + * @ingroup tcp_raw + * 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(). + * If memory is not available for creating the new pcb, NULL is returned. + * + * @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); +} + +/** + * @ingroup tcp_raw + * 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(). + * + * @param type IP address type, see @ref lwip_ip_addr_type definitions. + * If you want to listen to IPv4 and IPv6 (dual-stack) connections, + * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE. + * @return a new tcp_pcb that initially is in state CLOSED + */ +struct tcp_pcb * +tcp_new_ip_type(u8_t type) +{ + struct tcp_pcb *pcb; + pcb = tcp_alloc(TCP_PRIO_NORMAL); +#if LWIP_IPV4 && LWIP_IPV6 + if (pcb != NULL) { + IP_SET_TYPE_VAL(pcb->local_ip, type); + IP_SET_TYPE_VAL(pcb->remote_ip, type); + } +#else + LWIP_UNUSED_ARG(type); +#endif /* LWIP_IPV4 && LWIP_IPV6 */ + return pcb; +} + +/** + * @ingroup tcp_raw + * Specifies the program specific state that should be passed to all + * other callback functions. The "pcb" argument is the current TCP + * connection control block, and the "arg" argument is the argument + * that will be passed to the callbacks. + * + * @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) +{ + LWIP_ASSERT_CORE_LOCKED(); + /* This function is allowed to be called for both listen pcbs and + connection pcbs. */ + if (pcb != NULL) { + pcb->callback_arg = arg; + } +} +#if LWIP_CALLBACK_API + +/** + * @ingroup tcp_raw + * Sets the callback function that will be called when new data + * arrives. The callback function will be passed a NULL pbuf to + * indicate that the remote host has closed the connection. If the + * callback function returns ERR_OK or ERR_ABRT it must have + * freed the pbuf, otherwise it must not have freed it. + * + * @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) +{ + LWIP_ASSERT_CORE_LOCKED(); + if (pcb != NULL) { + LWIP_ASSERT("invalid socket state for recv callback", pcb->state != LISTEN); + pcb->recv = recv; + } +} + +/** + * @ingroup tcp_raw + * Specifies the callback function that should be called when data has + * successfully been received (i.e., acknowledged) by the remote + * host. The len argument passed to the callback function gives the + * amount bytes that was acknowledged by the last acknowledgment. + * + * @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) +{ + LWIP_ASSERT_CORE_LOCKED(); + if (pcb != NULL) { + LWIP_ASSERT("invalid socket state for sent callback", pcb->state != LISTEN); + pcb->sent = sent; + } +} + +/** + * @ingroup tcp_raw + * Used to specify the function that should be called when a fatal error + * has occurred on the connection. + * + * If a connection is aborted because of an error, the application is + * alerted of this event by the err callback. Errors that might abort a + * connection are when there is a shortage of memory. The callback + * function to be called is set using the tcp_err() function. + * + * @note The corresponding pcb is already freed when this callback is called! + * + * @param pcb tcp_pcb to set the err callback + * @param err callback function to call for this pcb when a fatal error + * has occurred on the connection + */ +void +tcp_err(struct tcp_pcb *pcb, tcp_err_fn err) +{ + LWIP_ASSERT_CORE_LOCKED(); + if (pcb != NULL) { + LWIP_ASSERT("invalid socket state for err callback", pcb->state != LISTEN); + pcb->errf = err; + } +} + +/** + * @ingroup tcp_raw + * 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) +{ + LWIP_ASSERT_CORE_LOCKED(); + if ((pcb != NULL) && (pcb->state == LISTEN)) { + struct tcp_pcb_listen *lpcb = (struct tcp_pcb_listen *)pcb; + lpcb->accept = accept; + } +} +#endif /* LWIP_CALLBACK_API */ + + +/** + * @ingroup tcp_raw + * Specifies the polling interval and the callback function that should + * be called to poll the application. The interval is specified in + * number of TCP coarse grained timer shots, which typically occurs + * twice a second. An interval of 10 means that the application would + * be polled every 5 seconds. + * + * 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. + */ +void +tcp_poll(struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval) +{ + LWIP_ASSERT_CORE_LOCKED(); + + LWIP_ERROR("tcp_poll: invalid pcb", pcb != NULL, return); + LWIP_ASSERT("invalid socket state for poll", pcb->state != LISTEN); + +#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) +{ + LWIP_ERROR("tcp_pcb_purge: invalid pcb", pcb != NULL, return); + + if (pcb->state != CLOSED && + pcb->state != TIME_WAIT && + pcb->state != LISTEN) { + + LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n")); + + tcp_backlog_accepted(pcb); + + 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_free_ooseq(pcb); + } +#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) +{ + LWIP_ASSERT("tcp_pcb_remove: invalid pcb", pcb != NULL); + LWIP_ASSERT("tcp_pcb_remove: invalid pcblist", pcblist != NULL); + + 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)) { + tcp_ack_now(pcb); + 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; + /* reset the local port to prevent the pcb from being 'bound' */ + pcb->local_port = 0; + + 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(struct tcp_pcb *pcb) +{ +#ifdef LWIP_HOOK_TCP_ISN + LWIP_ASSERT("tcp_next_iss: invalid pcb", pcb != NULL); + return LWIP_HOOK_TCP_ISN(&pcb->local_ip, pcb->local_port, &pcb->remote_ip, pcb->remote_port); +#else /* LWIP_HOOK_TCP_ISN */ + static u32_t iss = 6510; + + LWIP_ASSERT("tcp_next_iss: invalid pcb", pcb != NULL); + LWIP_UNUSED_ARG(pcb); + + iss += tcp_ticks; /* XXX */ + return iss; +#endif /* LWIP_HOOK_TCP_ISN */ +} + +#if TCP_CALCULATE_EFF_SEND_MSS +/** + * Calculates the effective send mss that can be used for a specific IP address + * by calculating the minimum of TCP_MSS and the mtu (if set) of the target + * netif (if not NULL). + */ +u16_t +tcp_eff_send_mss_netif(u16_t sendmss, struct netif *outif, const ip_addr_t *dest) +{ + u16_t mss_s; + u16_t mtu; + + LWIP_UNUSED_ARG(dest); /* in case IPv6 is disabled */ + + LWIP_ASSERT("tcp_eff_send_mss_netif: invalid dst_ip", dest != NULL); + +#if LWIP_IPV6 +#if LWIP_IPV4 + if (IP_IS_V6(dest)) +#endif /* LWIP_IPV4 */ + { + /* First look in destination cache, to see if there is a Path MTU. */ + mtu = nd6_get_destination_mtu(ip_2_ip6(dest), outif); + } +#if LWIP_IPV4 + else +#endif /* LWIP_IPV4 */ +#endif /* LWIP_IPV6 */ +#if LWIP_IPV4 + { + if (outif == NULL) { + return sendmss; + } + mtu = outif->mtu; + } +#endif /* LWIP_IPV4 */ + + if (mtu != 0) { + u16_t offset; +#if LWIP_IPV6 +#if LWIP_IPV4 + if (IP_IS_V6(dest)) +#endif /* LWIP_IPV4 */ + { + offset = IP6_HLEN + TCP_HLEN; + } +#if LWIP_IPV4 + else +#endif /* LWIP_IPV4 */ +#endif /* LWIP_IPV6 */ +#if LWIP_IPV4 + { + offset = IP_HLEN + TCP_HLEN; + } +#endif /* LWIP_IPV4 */ + mss_s = (mtu > offset) ? (u16_t)(mtu - offset) : 0; + /* 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 */ + +/** Helper function for tcp_netif_ip_addr_changed() that iterates a pcb list */ +static void +tcp_netif_ip_addr_changed_pcblist(const ip_addr_t *old_addr, struct tcp_pcb *pcb_list) +{ + struct tcp_pcb *pcb; + pcb = pcb_list; + + LWIP_ASSERT("tcp_netif_ip_addr_changed_pcblist: invalid old_addr", old_addr != NULL); + + while (pcb != NULL) { + /* PCB bound to current local interface address? */ + if (ip_addr_cmp(&pcb->local_ip, old_addr) +#if LWIP_AUTOIP + /* connections to link-local addresses must persist (RFC3927 ch. 1.9) */ + && (!IP_IS_V4_VAL(pcb->local_ip) || !ip4_addr_islinklocal(ip_2_ip4(&pcb->local_ip))) +#endif /* LWIP_AUTOIP */ + ) { + /* this connection must be aborted */ + struct tcp_pcb *next = pcb->next; + LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_STATE, ("netif_set_ipaddr: aborting TCP pcb %p\n", (void *)pcb)); + tcp_abort(pcb); + pcb = next; + } else { + pcb = pcb->next; + } + } +} + +/** This function is called from netif.c when address is changed or netif is removed + * + * @param old_addr IP address of the netif before change + * @param new_addr IP address of the netif after change or NULL if netif has been removed + */ +void +tcp_netif_ip_addr_changed(const ip_addr_t *old_addr, const ip_addr_t *new_addr) +{ + struct tcp_pcb_listen *lpcb; + + if (!ip_addr_isany(old_addr)) { + tcp_netif_ip_addr_changed_pcblist(old_addr, tcp_active_pcbs); + tcp_netif_ip_addr_changed_pcblist(old_addr, tcp_bound_pcbs); + + if (!ip_addr_isany(new_addr)) { + /* PCB bound to current local interface address? */ + for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) { + /* PCB bound to current local interface address? */ + if (ip_addr_cmp(&lpcb->local_ip, old_addr)) { + /* The PCB is listening to the old ipaddr and + * is set to listen to the new one instead */ + ip_addr_copy(lpcb->local_ip, *new_addr); + } + } + } + } +} + +const char * +tcp_debug_state_str(enum tcp_state s) +{ + return tcp_state_str[s]; +} + +err_t +tcp_tcp_get_tcp_addrinfo(struct tcp_pcb *pcb, int local, ip_addr_t *addr, u16_t *port) +{ + if (pcb) { + if (local) { + if (addr) { + *addr = pcb->local_ip; + } + if (port) { + *port = pcb->local_port; + } + } else { + if (addr) { + *addr = pcb->remote_ip; + } + if (port) { + *port = pcb->remote_port; + } + } + return ERR_OK; + } + return ERR_VAL; +} + +#if TCP_QUEUE_OOSEQ +/* Free all ooseq pbufs (and possibly reset SACK state) */ +void +tcp_free_ooseq(struct tcp_pcb *pcb) +{ + if (pcb->ooseq) { + tcp_segs_free(pcb->ooseq); + pcb->ooseq = NULL; +#if LWIP_TCP_SACK_OUT + memset(pcb->rcv_sacks, 0, sizeof(pcb->rcv_sacks)); +#endif /* LWIP_TCP_SACK_OUT */ + } +} +#endif /* TCP_QUEUE_OOSEQ */ + +#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", + lwip_ntohs(tcphdr->src), lwip_ntohs(tcphdr->dest))); + LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); + LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n", + lwip_ntohl(tcphdr->seqno))); + LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); + LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n", + lwip_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), + (u16_t)(TCPH_FLAGS(tcphdr) >> 5 & 1), + (u16_t)(TCPH_FLAGS(tcphdr) >> 4 & 1), + (u16_t)(TCPH_FLAGS(tcphdr) >> 3 & 1), + (u16_t)(TCPH_FLAGS(tcphdr) >> 2 & 1), + (u16_t)(TCPH_FLAGS(tcphdr) >> 1 & 1), + (u16_t)(TCPH_FLAGS(tcphdr) & 1), + lwip_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", + lwip_ntohs(tcphdr->chksum), lwip_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; + struct tcp_pcb_listen *pcbl; + + 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 (pcbl = tcp_listen_pcbs.listen_pcbs; pcbl != NULL; pcbl = pcbl->next) { + LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F" ", pcbl->local_port)); + tcp_debug_print_state(pcbl->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 */ + +#if LWIP_TCP_PCB_NUM_EXT_ARGS +/** + * @defgroup tcp_raw_extargs ext arguments + * @ingroup tcp_raw + * Additional data storage per tcp pcb\n + * @see @ref tcp_raw + * + * When LWIP_TCP_PCB_NUM_EXT_ARGS is > 0, every tcp pcb (including listen pcb) + * includes a number of additional argument entries in an array. + * + * To support memory management, in addition to a 'void *', callbacks can be + * provided to manage transition from listening pcbs to connections and to + * deallocate memory when a pcb is deallocated (see struct @ref tcp_ext_arg_callbacks). + * + * After allocating this index, use @ref tcp_ext_arg_set and @ref tcp_ext_arg_get + * to store and load arguments from this index for a given pcb. + */ + +static u8_t tcp_ext_arg_id; + +/** + * @ingroup tcp_raw_extargs + * Allocate an index to store data in ext_args member of struct tcp_pcb. + * Returned value is an index in mentioned array. + * The index is *global* over all pcbs! + * + * When @ref LWIP_TCP_PCB_NUM_EXT_ARGS is > 0, every tcp pcb (including listen pcb) + * includes a number of additional argument entries in an array. + * + * To support memory management, in addition to a 'void *', callbacks can be + * provided to manage transition from listening pcbs to connections and to + * deallocate memory when a pcb is deallocated (see struct @ref tcp_ext_arg_callbacks). + * + * After allocating this index, use @ref tcp_ext_arg_set and @ref tcp_ext_arg_get + * to store and load arguments from this index for a given pcb. + * + * @return a unique index into struct tcp_pcb.ext_args + */ +u8_t +tcp_ext_arg_alloc_id(void) +{ + u8_t result = tcp_ext_arg_id; + tcp_ext_arg_id++; + + LWIP_ASSERT_CORE_LOCKED(); + +#if LWIP_TCP_PCB_NUM_EXT_ARGS >= 255 +#error LWIP_TCP_PCB_NUM_EXT_ARGS +#endif + LWIP_ASSERT("Increase LWIP_TCP_PCB_NUM_EXT_ARGS in lwipopts.h", result < LWIP_TCP_PCB_NUM_EXT_ARGS); + return result; +} + +/** + * @ingroup tcp_raw_extargs + * Set callbacks for a given index of ext_args on the specified pcb. + * + * @param pcb tcp_pcb for which to set the callback + * @param id ext_args index to set (allocated via @ref tcp_ext_arg_alloc_id) + * @param callbacks callback table (const since it is referenced, not copied!) + */ +void +tcp_ext_arg_set_callbacks(struct tcp_pcb *pcb, uint8_t id, const struct tcp_ext_arg_callbacks * const callbacks) +{ + LWIP_ASSERT("pcb != NULL", pcb != NULL); + LWIP_ASSERT("id < LWIP_TCP_PCB_NUM_EXT_ARGS", id < LWIP_TCP_PCB_NUM_EXT_ARGS); + LWIP_ASSERT("callbacks != NULL", callbacks != NULL); + + LWIP_ASSERT_CORE_LOCKED(); + + pcb->ext_args[id].callbacks = callbacks; +} + +/** + * @ingroup tcp_raw_extargs + * Set data for a given index of ext_args on the specified pcb. + * + * @param pcb tcp_pcb for which to set the data + * @param id ext_args index to set (allocated via @ref tcp_ext_arg_alloc_id) + * @param arg data pointer to set + */ +void tcp_ext_arg_set(struct tcp_pcb *pcb, uint8_t id, void *arg) +{ + LWIP_ASSERT("pcb != NULL", pcb != NULL); + LWIP_ASSERT("id < LWIP_TCP_PCB_NUM_EXT_ARGS", id < LWIP_TCP_PCB_NUM_EXT_ARGS); + + LWIP_ASSERT_CORE_LOCKED(); + + pcb->ext_args[id].data = arg; +} + +/** + * @ingroup tcp_raw_extargs + * Set data for a given index of ext_args on the specified pcb. + * + * @param pcb tcp_pcb for which to set the data + * @param id ext_args index to set (allocated via @ref tcp_ext_arg_alloc_id) + * @return data pointer at the given index + */ +void *tcp_ext_arg_get(const struct tcp_pcb *pcb, uint8_t id) +{ + LWIP_ASSERT("pcb != NULL", pcb != NULL); + LWIP_ASSERT("id < LWIP_TCP_PCB_NUM_EXT_ARGS", id < LWIP_TCP_PCB_NUM_EXT_ARGS); + + LWIP_ASSERT_CORE_LOCKED(); + + return pcb->ext_args[id].data; +} + +/** This function calls the "destroy" callback for all ext_args once a pcb is + * freed. + */ +static void +tcp_ext_arg_invoke_callbacks_destroyed(struct tcp_pcb_ext_args *ext_args) +{ + int i; + LWIP_ASSERT("ext_args != NULL", ext_args != NULL); + + for (i = 0; i < LWIP_TCP_PCB_NUM_EXT_ARGS; i++) { + if (ext_args[i].callbacks != NULL) { + if (ext_args[i].callbacks->destroy != NULL) { + ext_args[i].callbacks->destroy((u8_t)i, ext_args[i].data); + } + } + } +} + +/** This function calls the "passive_open" callback for all ext_args if a connection + * is in the process of being accepted. This is called just after the SYN is + * received and before a SYN/ACK is sent, to allow to modify the very first + * segment sent even on passive open. Naturally, the "accepted" callback of the + * pcb has not been called yet! + */ +err_t +tcp_ext_arg_invoke_callbacks_passive_open(struct tcp_pcb_listen *lpcb, struct tcp_pcb *cpcb) +{ + int i; + LWIP_ASSERT("lpcb != NULL", lpcb != NULL); + LWIP_ASSERT("cpcb != NULL", cpcb != NULL); + + for (i = 0; i < LWIP_TCP_PCB_NUM_EXT_ARGS; i++) { + if (lpcb->ext_args[i].callbacks != NULL) { + if (lpcb->ext_args[i].callbacks->passive_open != NULL) { + err_t err = lpcb->ext_args[i].callbacks->passive_open((u8_t)i, lpcb, cpcb); + if (err != ERR_OK) { + return err; + } + } + } + } + return ERR_OK; +} +#endif /* LWIP_TCP_PCB_NUM_EXT_ARGS */ + +#endif /* LWIP_TCP */ |