/**
* 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(TCP_PCB *pcb, uint16 reset)
{
uint32 seqno, ackno;
uint16 remote_port, local_port;
IP_ADDR remote_ip, local_ip;
/* if there is an outstanding delayed ACKs, send it */
if (pcb->state != TIME_WAIT && pcb->flags & TF_ACK_DELAY)
{
pcb->flags |= TF_ACK_NOW;
tcp_output(pcb);
}
/* 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)
{
pcb->state = CLOSED;
tcp_pcb_purge(pcb);
tcp_close(pcb);
}
else
{
seqno = pcb->snd_nxt;
ackno = pcb->rcv_nxt;
ip_addr_set(&local_ip, &(pcb->local_ip));
ip_addr_set(&remote_ip, &(pcb->remote_ip));
local_port = pcb->local_port;
remote_port = pcb->remote_port;
pcb->state = CLOSED;
if (pcb->unacked != NULL)
{
tcp_segs_free(pcb->unacked);
pcb->unacked = NULL;
}
if (pcb->unsent != NULL)
{
tcp_segs_free(pcb->unsent);
pcb->unsent = NULL;
}
if (pcb->ooseq != NULL)
{
tcp_segs_free(pcb->ooseq);
pcb->ooseq = NULL;
}
if (reset)
{
printf("tcp rst tcp_abandon!\n");
tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
}
}
}
/******************************************************************************
* FunctionName : espconn_tcp_disconnect
* Description : disconnect with host
* Parameters : arg -- Additional argument to pass to the callback function
* Returns : none
*******************************************************************************/
static void ICACHE_FLASH_ATTR
espconn_tcp_disconnect_successful(void *arg)
{
espconn_msg *pdiscon_cb = arg;
sint8 dis_err = 0;
espconn_buf *pdis_buf = NULL;
espconn_buf *pdis_back = NULL;
espconn_kill_oldest_pcb();
if (pdiscon_cb != NULL) {
struct espconn *espconn = pdiscon_cb->preverse;
dis_err = pdiscon_cb->pcommon.err;
if (pdiscon_cb->pespconn != NULL){
struct tcp_pcb *pcb = NULL;
if (espconn != NULL){/*Process the server's message block*/
if (pdiscon_cb->pespconn->proto.tcp != NULL && espconn->proto.tcp){
espconn_copy_partial(espconn, pdiscon_cb->pespconn);
espconn_printf("server: %d.%d.%d.%d : %d disconnect\n", espconn->proto.tcp->remote_ip[0],
espconn->proto.tcp->remote_ip[1],espconn->proto.tcp->remote_ip[2],
espconn->proto.tcp->remote_ip[3],espconn->proto.tcp->remote_port);
free(pdiscon_cb->pespconn->proto.tcp);
pdiscon_cb->pespconn->proto.tcp = NULL;
}
free(pdiscon_cb->pespconn);
pdiscon_cb->pespconn = NULL;
} else {/*Process the client's message block*/
espconn = pdiscon_cb->pespconn;
espconn_printf("client: %d.%d.%d.%d : %d disconnect\n", espconn->proto.tcp->local_ip[0],
espconn->proto.tcp->local_ip[1],espconn->proto.tcp->local_ip[2],
espconn->proto.tcp->local_ip[3],espconn->proto.tcp->local_port);
}
/*process the current TCP block*/
pcb = espconn_find_current_pcb(pdiscon_cb);
if (pcb != NULL){
if (espconn_reuse_disabled(pdiscon_cb)) {
struct tcp_pcb *cpcb = NULL;
struct tcp_pcb *prev = NULL;
uint8_t pcb_remove;
espconn_printf("espconn_tcp_disconnect_successful %d, %d\n", pcb->state, pcb->local_port);
cpcb = tcp_tw_pcbs;
while (cpcb != NULL) {
pcb_remove = 0;
if (cpcb->local_port == pcb->local_port) {
++pcb_remove;
}
/* If the PCB should be removed, do it. */
if (pcb_remove) {
struct tcp_pcb *backup_pcb = NULL;
tcp_pcb_purge(cpcb);
/* Remove PCB from tcp_tw_pcbs list. */
if (prev != NULL) {
LWIP_ASSERT("espconn_tcp_delete: middle cpcb != tcp_tw_pcbs",cpcb != tcp_tw_pcbs);
prev->next = cpcb->next;
} else {
/* This PCB was the first. */
LWIP_ASSERT("espconn_tcp_delete: first cpcb == tcp_tw_pcbs",tcp_tw_pcbs == cpcb);
tcp_tw_pcbs = cpcb->next;
}
backup_pcb = cpcb;
cpcb = cpcb->next;
memp_free(MEMP_TCP_PCB, backup_pcb);
} else {
prev = cpcb;
cpcb = cpcb->next;
}
}
} else {
tcp_arg(pcb, NULL);
tcp_err(pcb, NULL);
}
}
}
/*to prevent memory leaks, ensure that each allocated is deleted*/
pdis_buf = pdiscon_cb->pcommon.pbuf;
while (pdis_buf != NULL) {
pdis_back = pdis_buf;
pdis_buf = pdis_back->pnext;
espconn_pbuf_delete(&pdiscon_cb->pcommon.pbuf, pdis_back);
free(pdis_back);
pdis_back = NULL;
}
bzero(&pktinfo[0], sizeof(struct espconn_packet));
memcpy(&pktinfo[0], (void*)&pdiscon_cb->pcommon.packet_info, sizeof(struct espconn_packet));
free(pdiscon_cb);
pdiscon_cb = NULL;
if (espconn->proto.tcp && espconn->proto.tcp->disconnect_callback != NULL) {
espconn->proto.tcp->disconnect_callback(espconn);
}
} else {
espconn_printf("espconn_tcp_disconnect err\n");
}
}
/**
* Closes the TX side of a connection held by the PCB.
* For tcp_close(), a RST is sent if the application didn't receive all data
* (tcp_recved() not called for all data passed to recv callback).
*
* Listening pcbs are freed and may not be referenced any more.
* Connection pcbs are freed if not yet connected and may not be referenced
* any more. If a connection is established (at least SYN received or in
* a closing state), the connection is closed, and put in a closing state.
* The pcb is then automatically freed in tcp_slowtmr(). It is therefore
* unsafe to reference it.
*
* @param pcb the tcp_pcb to close
* @return ERR_OK if connection has been closed
* another err_t if closing failed and pcb is not freed
*/
static err_t
tcp_close_shutdown(struct tcp_pcb *pcb, u8_t rst_on_unacked_data)
{
err_t err;
if (rst_on_unacked_data && (pcb->state != LISTEN)) {
if ((pcb->refused_data != NULL) || (pcb->rcv_wnd != TCP_WND)) {
/* Not all data received by application, send RST to tell the remote
side about this. */
LWIP_ASSERT("pcb->flags & TF_RXCLOSED", pcb->flags & TF_RXCLOSED);
/* don't call tcp_abort here: we must not deallocate the pcb since
that might not be expected when calling tcp_close */
tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip,
pcb->local_port, pcb->remote_port);
tcp_pcb_purge(pcb);
/* TODO: to which state do we move now? */
/* move to TIME_WAIT since we close actively */
TCP_RMV(&tcp_active_pcbs, pcb);
pcb->state = TIME_WAIT;
TCP_REG(&tcp_tw_pcbs, pcb);
return ERR_OK;
}
}
switch (pcb->state) {
case CLOSED:
/* Closing a pcb in the CLOSED state might seem erroneous,
* however, it is in this state once allocated and as yet unused
* and the user needs some way to free it should the need arise.
* Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
* or for a pcb that has been used and then entered the CLOSED state
* is erroneous, but this should never happen as the pcb has in those cases
* been freed, and so any remaining handles are bogus. */
err = ERR_OK;
if (pcb->local_port != 0) {
TCP_RMV(&tcp_bound_pcbs, pcb);
}
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case LISTEN:
err = ERR_OK;
tcp_pcb_remove(&tcp_listen_pcbs.pcbs, pcb);
memp_free(MEMP_TCP_PCB_LISTEN, pcb);
pcb = NULL;
break;
case SYN_SENT:
err = ERR_OK;
tcp_pcb_remove(&tcp_active_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
snmp_inc_tcpattemptfails();
break;
case SYN_RCVD:
err = tcp_send_fin(pcb);
if (err == ERR_OK) {
snmp_inc_tcpattemptfails();
pcb->state = FIN_WAIT_1;
}
break;
case ESTABLISHED:
err = tcp_send_fin(pcb);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_fin(pcb);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
pcb->state = LAST_ACK;
}
break;
default:
/* Has already been closed, do nothing. */
err = ERR_OK;
pcb = NULL;
break;
}
if (pcb != NULL && err == ERR_OK) {
/* To ensure all data has been sent when tcp_close returns, we have
to make sure tcp_output doesn't fail.
Since we don't really have to ensure all data has been sent when tcp_close
returns (unsent data is sent from tcp timer functions, also), we don't care
for the return value of tcp_output for now. */
/* @todo: When implementing SO_LINGER, this must be changed somehow:
If SOF_LINGER is set, the data should be sent and acked before close returns.
This can only be valid for sequential APIs, not for the raw API. */
tcp_output(pcb);
}
return err;
}
/**
* 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)
{
TCP_PCB *pcb, *pcb2, *prev;
uint16 eff_wnd;
uint8 err= ERR_OK;
++tcp_ticks;
/* Steps through all of the active PCBs. */
prev = NULL;
pcb = &stTcpPcb;
if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX)
{
printf("SYN SENT CLOSED\n");
pcb->state = CLOSED;
tcp_pcb_purge(pcb);
tcp_close(pcb);
return;
}
else if (pcb->nrtx == TCP_MAXRTX)
{
printf("TCP MAXRTX CLOSED\n");
pcb->state = CLOSED;
tcp_pcb_purge(pcb);
tcp_close(pcb);
return;
}
else
{
if (pcb->persist_backoff > 0)
{
/* If snd_wnd is zero, use persist timer to send 1 byte probes
* instead of using the standard retransmission mechanism. */
pcb->persist_cnt++;
if (pcb->persist_cnt >= tcp_persist_backoff[pcb->persist_backoff-1])
{
pcb->persist_cnt = 0;
if (pcb->persist_backoff < sizeof(tcp_persist_backoff))
{
pcb->persist_backoff++;
}
tcp_zero_window_probe(pcb);
}
}
else
{
/* Increase the retransmission timer if it is running */
if (pcb->rtime >= 0)
++pcb->rtime;
if (pcb->unacked != NULL && pcb->rtime >= pcb->rto)
{
/* Double retransmission time-out unless we are trying to
* connect to somebody (i.e., we are in SYN_SENT). */
if (pcb->state != SYN_SENT)
{
pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
}
/* Reset the retransmission timer. */
pcb->rtime = 0;
/* Reduce congestion window and ssthresh. */
eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
pcb->ssthresh = eff_wnd >> 1;
if (pcb->ssthresh < pcb->mss)
{
pcb->ssthresh = pcb->mss * 2;
}
pcb->cwnd = pcb->mss;
/* The following needs to be called AFTER cwnd is set to one
mss - STJ */
tcp_rexmit_rto(pcb);
}
}
}
/**
* Implements the TCP state machine. Called by tcp_input. In some
* states tcp_receive() is called to receive data. The tcp_seg
* argument will be freed by the caller (tcp_input()) unless the
* recv_data pointer in the pcb is set.
*
* @param pcb the tcp_pcb for which a segment arrived
*
* @note the segment which arrived is saved in global variables, therefore only the pcb
* involved is passed as a parameter to this function
*/
static err_t
tcp_process(struct tcp_pcb *pcb)
{
struct tcp_seg *rseg;
u8_t acceptable = 0;
err_t err;
u8_t accepted_inseq;
err = ERR_OK;
/* Process incoming RST segments. */
if (flags & TCP_RST) {
/* First, determine if the reset is acceptable. */
if (pcb->state == SYN_SENT) {
if (ackno == pcb->snd_nxt) {
acceptable = 1;
}
} else {
if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
pcb->rcv_nxt+pcb->rcv_ann_wnd)) {
acceptable = 1;
}
}
if (acceptable) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
recv_flags = TF_RESET;
pcb->flags &= ~TF_ACK_DELAY;
return ERR_RST;
} else {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
seqno, pcb->rcv_nxt));
LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
seqno, pcb->rcv_nxt));
return ERR_OK;
}
}
/* Update the PCB (in)activity timer. */
pcb->tmr = tcp_ticks;
pcb->keep_cnt_sent = 0;
/* Do different things depending on the TCP state. */
switch (pcb->state) {
case SYN_SENT:
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
/* received SYN ACK with expected sequence number? */
if ((flags & TCP_ACK) && (flags & TCP_SYN)
&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
pcb->snd_buf++;
pcb->rcv_nxt = seqno + 1;
pcb->lastack = ackno;
pcb->snd_wnd = tcphdr->wnd;
pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
pcb->state = ESTABLISHED;
/* Parse any options in the SYNACK before using pcb->mss since that
* can be changed by the received options! */
tcp_parseopt(pcb);
#if TCP_CALCULATE_EFF_SEND_MSS
pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
#endif /* TCP_CALCULATE_EFF_SEND_MSS */
/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
* but for the default value of pcb->mss) */
pcb->ssthresh = pcb->mss * 10;
pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
--pcb->snd_queuelen;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
rseg = pcb->unacked;
pcb->unacked = rseg->next;
/* If there's nothing left to acknowledge, stop the retransmit
timer, otherwise reset it to start again */
if(pcb->unacked == NULL)
pcb->rtime = -1;
else {
pcb->rtime = 0;
pcb->nrtx = 0;
}
tcp_seg_free(rseg);
/* Call the user specified function to call when sucessfully
* connected. */
TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
tcp_ack_now(pcb);
}
/* received ACK? possibly a half-open connection */
else if (flags & TCP_ACK) {
/* send a RST to bring the other side in a non-synchronized state. */
tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
tcphdr->dest, tcphdr->src);
}
break;
case SYN_RCVD:
if (flags & TCP_ACK &&
!(flags & TCP_RST)) {
/* expected ACK number? */
if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
u16_t old_cwnd;
pcb->state = ESTABLISHED;
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
#if LWIP_CALLBACK_API
LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
#endif
/* Call the accept function. */
TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
if (err != ERR_OK) {
/* If the accept function returns with an error, we abort
* the connection. */
tcp_abort(pcb);
return ERR_ABRT;
}
old_cwnd = pcb->cwnd;
/* If there was any data contained within this ACK,
* we'd better pass it on to the application as well. */
accepted_inseq = tcp_receive(pcb);
pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
if ((flags & TCP_FIN) && accepted_inseq) {
tcp_ack_now(pcb);
pcb->state = CLOSE_WAIT;
}
}
/* incorrect ACK number */
else {
/* send RST */
tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
tcphdr->dest, tcphdr->src);
}
}
break;
case CLOSE_WAIT:
/* FALLTHROUGH */
case ESTABLISHED:
accepted_inseq = tcp_receive(pcb);
if ((flags & TCP_FIN) && accepted_inseq) { /* passive close */
tcp_ack_now(pcb);
pcb->state = CLOSE_WAIT;
}
break;
case FIN_WAIT_1:
tcp_receive(pcb);
if (flags & TCP_FIN) {
if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
LWIP_DEBUGF(TCP_DEBUG,
("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
tcp_ack_now(pcb);
tcp_pcb_purge(pcb);
TCP_RMV(&tcp_active_pcbs, pcb);
pcb->state = TIME_WAIT;
TCP_REG(&tcp_tw_pcbs, pcb);
} else {
tcp_ack_now(pcb);
pcb->state = CLOSING;
}
} else if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
pcb->state = FIN_WAIT_2;
}
break;
case FIN_WAIT_2:
tcp_receive(pcb);
if (flags & TCP_FIN) {
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
tcp_ack_now(pcb);
tcp_pcb_purge(pcb);
TCP_RMV(&tcp_active_pcbs, pcb);
pcb->state = TIME_WAIT;
TCP_REG(&tcp_tw_pcbs, pcb);
}
break;
case CLOSING:
tcp_receive(pcb);
if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
tcp_ack_now(pcb);
tcp_pcb_purge(pcb);
TCP_RMV(&tcp_active_pcbs, pcb);
pcb->state = TIME_WAIT;
TCP_REG(&tcp_tw_pcbs, pcb);
}
break;
case LAST_ACK:
tcp_receive(pcb);
if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
recv_flags = TF_CLOSED;
}
break;
default:
break;
}
return ERR_OK;
}
