/**
* Closes the connection held by the PCB.
*
*/
err_t
tcp_close(struct tcp_pcb *pcb)
{
err_t err;
#if TCP_DEBUG
LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in state "));
tcp_debug_print_state(pcb->state);
LWIP_DEBUGF(TCP_DEBUG, ("\n"));
#endif /* TCP_DEBUG */
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;
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case LISTEN:
err = ERR_OK;
tcp_pcb_remove((struct tcp_pcb **)&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;
break;
case SYN_RCVD:
case ESTABLISHED:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
pcb->state = LAST_ACK;
}
break;
default:
/* Has already been closed, do nothing. */
err = ERR_OK;
pcb = NULL;
break;
}
if (pcb != NULL && err == ERR_OK) {
err = tcp_output(pcb);
}
return err;
}
/**
* Abandons a connection and optionally sends a RST to the remote
* host. Deletes the local protocol control block. This is done when
* a connection is killed because of shortage of memory.
*
* @param pcb the tcp_pcb to abort
* @param reset boolean to indicate whether a reset should be sent
*/
void
tcp_abandon(struct tcp_pcb *pcb, int reset)
{
u32_t seqno, ackno;
u16_t remote_port, local_port;
ip_addr_t remote_ip, local_ip;
#if LWIP_CALLBACK_API
tcp_err_fn errf;
#endif /* LWIP_CALLBACK_API */
void *errf_arg;
/* get_tcp_state(pcb) LISTEN not allowed here */
LWIP_ASSERT("don't call tcp_abort/tcp_abandon for listen-pcbs",
get_tcp_state(pcb) != LISTEN);
/* Figure out on which TCP PCB list we are, and remove us. If we
are in an active state, call the receive function associated with
the PCB with a NULL argument, and send an RST to the remote end. */
if (get_tcp_state(pcb) == TIME_WAIT) {
tcp_pcb_remove(pcb);
} else {
int send_rst = reset && (get_tcp_state(pcb) != CLOSED);
seqno = pcb->snd_nxt;
ackno = pcb->rcv_nxt;
ip_addr_copy(local_ip, pcb->local_ip);
ip_addr_copy(remote_ip, pcb->remote_ip);
local_port = pcb->local_port;
remote_port = pcb->remote_port;
#if LWIP_CALLBACK_API
errf = pcb->errf;
#endif /* LWIP_CALLBACK_API */
errf_arg = pcb->my_container;
tcp_pcb_remove(pcb);
if (pcb->unacked != NULL) {
tcp_tx_segs_free(pcb, pcb->unacked);
pcb->unacked = NULL;
}
if (pcb->unsent != NULL) {
tcp_tx_segs_free(pcb, pcb->unsent);
pcb->unsent = NULL;
}
#if TCP_QUEUE_OOSEQ
if (pcb->ooseq != NULL) {
tcp_segs_free(pcb, pcb->ooseq);
}
#endif /* TCP_QUEUE_OOSEQ */
TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
if (send_rst) {
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
tcp_rst(seqno, ackno, local_port, remote_port, pcb);
}
}
(void)local_ip; /* Fix warning -Wunused-but-set-variable */
(void)remote_ip; /* Fix warning -Wunused-but-set-variable */
}
/******************************************************************************
* FunctionName : espconn_kill_oldest
* Description : kill the oldest TCP block
* Parameters : none
* Returns : none
*******************************************************************************/
static void ICACHE_FLASH_ATTR
espconn_kill_oldest(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) {
tcp_abort(inactive);
}
/* Go through the list of FIN_WAIT_2 pcbs and get the oldest pcb. */
inactivity = 0;
inactive = NULL;
for (pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->state == FIN_WAIT_1 || pcb->state == FIN_WAIT_2){
if ((u32_t) (tcp_ticks - pcb->tmr) >= inactivity) {
inactivity = tcp_ticks - pcb->tmr;
inactive = pcb;
}
}
}
/*Purges the PCB, removes it from a PCB list and frees the memory*/
if (inactive != NULL) {
tcp_pcb_remove(&tcp_active_pcbs, inactive);
memp_free(MEMP_TCP_PCB, inactive);
}
/* Go through the list of LAST_ACK pcbs and get the oldest pcb. */
inactivity = 0;
inactive = NULL;
for (pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
if (pcb->state == LAST_ACK) {
if ((u32_t) (tcp_ticks - pcb->tmr) >= inactivity) {
inactivity = tcp_ticks - pcb->tmr;
inactive = pcb;
}
}
}
/*Purges the PCB, removes it from a PCB list and frees the memory*/
if (inactive != NULL) {
tcp_pcb_remove(&tcp_active_pcbs, inactive);
memp_free(MEMP_TCP_PCB, inactive);
}
}
///发送rst告诉远程 可以停止
///把本地的pcb给删了 ？free?
void
tcp_abandon(struct tcp_pcb *pcb, int reset)
{
u32_t seqno, ackno;
u16_t remote_port, local_port;
struct ip_addr remote_ip, local_ip;
#if LWIP_CALLBACK_API
void (* errf)(void *arg, err_t err);
#endif /* LWIP_CALLBACK_API */
void *errf_arg;
/* 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. */
//pcb处于等待状态 ，删了
//pcb处于act状态， 调用接收函数，将pcb清空？ 并且发送RST给远程
if (pcb->state == TIME_WAIT) {
printf("before jinhu 1 ");
tcp_pcb_remove(&tcp_tw_pcbs, pcb);
memp_free(MEMP_TCP_PCB, 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;
#if LWIP_CALLBACK_API
errf = pcb->errf;
#endif /* LWIP_CALLBACK_API */
errf_arg = pcb->callback_arg;
printf("bero jinhu 2");
tcp_pcb_remove(&tcp_active_pcbs, pcb);
if (pcb->unacked != NULL) {
tcp_segs_free(pcb->unacked);
}
if (pcb->unsent != NULL) {
tcp_segs_free(pcb->unsent);
}
#if TCP_QUEUE_OOSEQ
if (pcb->ooseq != NULL) {
tcp_segs_free(pcb->ooseq);
}
#endif /* TCP_QUEUE_OOSEQ */
memp_free(MEMP_TCP_PCB, pcb);
TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
if (reset) {
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
}
}
}
/*-----------------------------------------------------------------------------------*/
err_t
tcp_close(struct tcp_pcb *pcb)
{
err_t err;
#if TCP_DEBUG
DEBUGF(TCP_DEBUG, ("tcp_close: closing in state "));
tcp_debug_print_state(pcb->state);
DEBUGF(TCP_DEBUG, ("\n"));
#endif /* TCP_DEBUG */
switch(pcb->state) {
case LISTEN:
err = ERR_OK;
tcp_pcb_remove(TCP_LIST_LISTEN, pcb);
memp_free(MEMP_TCP_PCB_LISTEN, pcb);
pcb = NULL;
break;
case SYN_SENT:
err = ERR_OK;
tcp_pcb_remove(TCP_LIST_ACTIVE, pcb);
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case SYN_RCVD:
err = tcp_send_ctrl(pcb, TCP_FIN);
if(err == ERR_OK) {
pcb->state = FIN_WAIT_1;
}
break;
case ESTABLISHED:
err = tcp_send_ctrl(pcb, TCP_FIN);
if(err == ERR_OK) {
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_ctrl(pcb, TCP_FIN);
if(err == ERR_OK) {
pcb->state = LAST_ACK;
}
break;
default:
/* Has already been closed, do nothing. */
err = ERR_OK;
pcb = NULL;
break;
}
if(pcb != NULL && err == ERR_OK) {
err = tcp_output(pcb);
}
return err;
}
/**
* Abandons a connection and optionally sends a RST to the remote
* host. Deletes the local protocol control block. This is done when
* a connection is killed because of shortage of memory.
*
* @param pcb the tcp_pcb to abort
* @param reset boolean to indicate whether a reset should be sent
*/
void
tcp_abandon(struct tcp_pcb *pcb, int reset)
{
u32_t seqno, ackno;
u16_t remote_port, local_port;
ip_addr_t remote_ip, local_ip;
#if LWIP_CALLBACK_API
tcp_err_fn errf;
#endif /* LWIP_CALLBACK_API */
void *errf_arg;
/* pcb->state LISTEN not allowed here */
LWIP_ASSERT("don't call tcp_abort/tcp_abandon for listen-pcbs",
pcb->state != LISTEN);
/* Figure out on which TCP PCB list we are, and remove us. If we
are in an active state, call the receive function associated with
the PCB with a NULL argument, and send an RST to the remote end. */
if (pcb->state == TIME_WAIT) {
tcp_pcb_remove(&tcp_tw_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
} else {
seqno = pcb->snd_nxt;
ackno = pcb->rcv_nxt;
ip_addr_copy(local_ip, pcb->local_ip);
ip_addr_copy(remote_ip, pcb->remote_ip);
local_port = pcb->local_port;
remote_port = pcb->remote_port;
#if LWIP_CALLBACK_API
errf = pcb->errf;
#endif /* LWIP_CALLBACK_API */
errf_arg = pcb->callback_arg;
tcp_pcb_remove(&tcp_active_pcbs, pcb);
if (pcb->unacked != NULL) {
tcp_segs_free(pcb->unacked);
}
if (pcb->unsent != NULL) {
tcp_segs_free(pcb->unsent);
}
#if TCP_QUEUE_OOSEQ
if (pcb->ooseq != NULL) {
tcp_segs_free(pcb->ooseq);
}
#endif /* TCP_QUEUE_OOSEQ */
memp_free(MEMP_TCP_PCB, pcb);
TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
if (reset) {
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
}
}
}
/******************************************************************************
* FunctionName : espconn_kill_pcb
* Description : kill all the TCP block by port
* Parameters : none
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR espconn_kill_pcb(u16_t port)
{
struct tcp_pcb *cpcb = NULL;
uint8 i = 0;
struct tcp_pcb *inactive = NULL;
struct tcp_pcb *prev = NULL;
uint8_t pcb_remove;
/* Check if the address already is in use (on all lists) */
for (i = 1; i < 4; i++) {
cpcb = *tcp_pcb_lists[i];
while(cpcb != NULL){
pcb_remove = 0;
if (cpcb->local_port == port) {
++pcb_remove;
}
/* If the PCB should be removed, do it. */
if (pcb_remove) {
/* Remove PCB from tcp_pcb_lists list. */
inactive = cpcb;
cpcb = inactive->next;
tcp_pcb_remove(tcp_pcb_lists[i], inactive);
memp_free(MEMP_TCP_PCB, inactive);
} else {
cpcb = cpcb->next;
}
}
}
}
/******************************************************************************
* 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;
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){
if (pdiscon_cb->pespconn->proto.tcp != NULL){
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);
os_free(pdiscon_cb->pespconn->proto.tcp);
pdiscon_cb->pespconn->proto.tcp = NULL;
}
os_free(pdiscon_cb->pespconn);
pdiscon_cb->pespconn = NULL;
} else {
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);
}
pcb = find_tcpsrv_pcb(pdiscon_cb); // corrected PV`
if(pcb != NULL) { // added PV`
tcp_arg(pcb, NULL);
tcp_err(pcb, NULL);
} // added PV`
/*delete TIME_WAIT State pcb after 2MSL time,for not all data received by application.*/
if (pdiscon_cb->pcommon.espconn_opt == ESPCONN_REUSEADDR){
if ((pcb != NULL)&&(pcb->state == TIME_WAIT)){ // corrected PV`
tcp_pcb_remove(&tcp_tw_pcbs,pcb);
memp_free(MEMP_TCP_PCB,pcb);
}
}
}
os_free(pdiscon_cb);
pdiscon_cb = NULL;
if (espconn->proto.tcp->disconnect_callback != NULL) {
espconn->proto.tcp->disconnect_callback(espconn);
}
} else {
espconn_printf("espconn_tcp_disconnect err\n");
}
}
/*-----------------------------------------------------------------------------------*/
void
tcp_abort(struct tcp_pcb *pcb)
{
u32_t seqno, ackno;
u16_t remote_port, local_port;
struct ip_addr remote_ip, local_ip;
void (* errf)(void *arg, err_t err);
void *errf_arg;
/* 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_LIST_TW, pcb);
memp_free(MEMP_TCP_PCB, pcb);
} else if(pcb->state == LISTEN) {
tcp_pcb_remove(TCP_LIST_LISTEN, pcb);
memp_free(MEMP_TCP_PCB_LISTEN, 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;
errf = pcb->errf;
errf_arg = pcb->callback_arg;
tcp_pcb_remove(TCP_LIST_ACTIVE, pcb);
memp_free(MEMP_TCP_PCB, pcb);
if(errf != NULL) {
errf(errf_arg, ERR_ABRT);
}
DEBUGF(TCP_RST_DEBUG, ("tcp_abort: sending RST\n"));
tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
}
}
/**
* 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.
*
* @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)
{
err_t err;
#if TCP_DEBUG
LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
tcp_debug_print_state(pcb->state);
#endif /* TCP_DEBUG */
switch (pcb->state) {
case CLOSED:
/* Closing a pcb in the CLOSED state might seem erroneous,
* however, it is in this state once allocated and as yet unused
* and the user needs some way to free it should the need arise.
* Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
* or for a pcb that has been used and then entered the CLOSED state
* is erroneous, but this should never happen as the pcb has in those cases
* been freed, and so any remaining handles are bogus. */
err = ERR_OK;
TCP_RMV(&tcp_bound_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case LISTEN:
err = ERR_OK;
tcp_pcb_remove((struct tcp_pcb **)&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_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpattemptfails();
pcb->state = FIN_WAIT_1;
}
break;
case ESTABLISHED:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
pcb->state = FIN_WAIT_1;
}
break;
case CLOSE_WAIT:
err = tcp_send_ctrl(pcb, TCP_FIN);
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 when tcp_close returns. */
tcp_output(pcb);
}
return err;
}
/**
* 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;
}
/**
* The initial input processing of TCP. It verifies the TCP header, demultiplexes
* the segment between the PCBs and passes it on to tcp_process(), which implements
* the TCP finite state machine. This function is called by the IP layer (in
* ip_input()).
*
* @param p received TCP segment to process (p->payload pointing to the IP header)
* @param inp network interface on which this segment was received
*/
void
tcp_input(struct pbuf *p, struct netif *inp)
{
struct tcp_pcb *pcb, *prev;
struct tcp_pcb_listen *lpcb;
u8_t hdrlen;
err_t err;
PERF_START;
TCP_STATS_INC(tcp.recv);
snmp_inc_tcpinsegs();
iphdr = p->payload;
tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
#if TCP_INPUT_DEBUG
tcp_debug_print(tcphdr);
#endif
/* remove header from payload */
if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) {
/* drop short packets */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
TCP_STATS_INC(tcp.lenerr);
TCP_STATS_INC(tcp.drop);
snmp_inc_tcpinerrs();
pbuf_free(p);
return;
}
/* Don't even process incoming broadcasts/multicasts. */
if (ip_addr_isbroadcast(&(iphdr->dest), inp) ||
ip_addr_ismulticast(&(iphdr->dest))) {
TCP_STATS_INC(tcp.proterr);
TCP_STATS_INC(tcp.drop);
snmp_inc_tcpinerrs();
pbuf_free(p);
return;
}
#if CHECKSUM_CHECK_TCP
/* Verify TCP checksum. */
if (inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
(struct ip_addr *)&(iphdr->dest),
IP_PROTO_TCP, p->tot_len) != 0) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src), (struct ip_addr *)&(iphdr->dest),
IP_PROTO_TCP, p->tot_len)));
#if TCP_DEBUG
tcp_debug_print(tcphdr);
#endif /* TCP_DEBUG */
TCP_STATS_INC(tcp.chkerr);
TCP_STATS_INC(tcp.drop);
snmp_inc_tcpinerrs();
pbuf_free(p);
return;
}
#endif
/* Move the payload pointer in the pbuf so that it points to the
TCP data instead of the TCP header. */
hdrlen = TCPH_HDRLEN(tcphdr);
if(pbuf_header(p, -(hdrlen * 4))){
/* drop short packets */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
TCP_STATS_INC(tcp.lenerr);
TCP_STATS_INC(tcp.drop);
snmp_inc_tcpinerrs();
pbuf_free(p);
return;
}
/* Convert fields in TCP header to host byte order. */
tcphdr->src = ntohs(tcphdr->src);
tcphdr->dest = ntohs(tcphdr->dest);
seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
tcphdr->wnd = ntohs(tcphdr->wnd);
flags = TCPH_FLAGS(tcphdr) & TCP_FLAGS;
tcplen = p->tot_len + ((flags & TCP_FIN || flags & TCP_SYN)? 1: 0);
/* Demultiplex an incoming segment. First, we check if it is destined
for an active connection. */
prev = NULL;
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
if (pcb->remote_port == tcphdr->src &&
pcb->local_port == tcphdr->dest &&
ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
/* Move this PCB to the front of the list so that subsequent
lookups will be faster (we exploit locality in TCP segment
arrivals). */
LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
if (prev != NULL) {
prev->next = pcb->next;
pcb->next = tcp_active_pcbs;
tcp_active_pcbs = pcb;
}
LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
break;
}
prev = pcb;
}
if (pcb == NULL) {
/* If it did not go to an active connection, we check the connections
in the TIME-WAIT state. */
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
if (pcb->remote_port == tcphdr->src &&
pcb->local_port == tcphdr->dest &&
ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
/* We don't really care enough to move this PCB to the front
of the list since we are not very likely to receive that
many segments for connections in TIME-WAIT. */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
tcp_timewait_input(pcb);
pbuf_free(p);
return;
}
}
/* Finally, if we still did not get a match, we check all PCBs that
are LISTENing for incoming connections. */
prev = NULL;
for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
if ((ip_addr_isany(&(lpcb->local_ip)) ||
ip_addr_cmp(&(lpcb->local_ip), &(iphdr->dest))) &&
lpcb->local_port == tcphdr->dest) {
/* Move this PCB to the front of the list so that subsequent
lookups will be faster (we exploit locality in TCP segment
arrivals). */
if (prev != NULL) {
((struct tcp_pcb_listen *)prev)->next = lpcb->next;
/* our successor is the remainder of the listening list */
lpcb->next = tcp_listen_pcbs.listen_pcbs;
/* put this listening pcb at the head of the listening list */
tcp_listen_pcbs.listen_pcbs = lpcb;
}
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
tcp_listen_input(lpcb);
pbuf_free(p);
return;
}
prev = (struct tcp_pcb *)lpcb;
}
}
#if TCP_INPUT_DEBUG
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
#endif /* TCP_INPUT_DEBUG */
if (pcb != NULL) {
/* The incoming segment belongs to a connection. */
#if TCP_INPUT_DEBUG
#if TCP_DEBUG
tcp_debug_print_state(pcb->state);
#endif /* TCP_DEBUG */
#endif /* TCP_INPUT_DEBUG */
/* Set up a tcp_seg structure. */
inseg.next = NULL;
inseg.len = p->tot_len;
inseg.dataptr = p->payload;
inseg.p = p;
inseg.tcphdr = tcphdr;
recv_data = NULL;
recv_flags = 0;
/* If there is data which was previously "refused" by upper layer */
if (pcb->refused_data != NULL) {
/* Notify again application with data previously received. */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
if (err == ERR_OK) {
pcb->refused_data = NULL;
} else {
/* drop incoming packets, because pcb is "full" */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
TCP_STATS_INC(tcp.drop);
snmp_inc_tcpinerrs();
pbuf_free(p);
return;
}
}
tcp_input_pcb = pcb;
err = tcp_process(pcb);
tcp_input_pcb = NULL;
/* A return value of ERR_ABRT means that tcp_abort() was called
and that the pcb has been freed. If so, we don't do anything. */
if (err != ERR_ABRT) {
if (recv_flags & TF_RESET) {
/* TF_RESET means that the connection was reset by the other
end. We then call the error callback to inform the
application that the connection is dead before we
deallocate the PCB. */
TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
tcp_pcb_remove(&tcp_active_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
} else if (recv_flags & TF_CLOSED) {
/* The connection has been closed and we will deallocate the
PCB. */
tcp_pcb_remove(&tcp_active_pcbs, pcb);
memp_free(MEMP_TCP_PCB, pcb);
} else {
err = ERR_OK;
/* If the application has registered a "sent" function to be
called when new send buffer space is available, we call it
now. */
if (pcb->acked > 0) {
TCP_EVENT_SENT(pcb, pcb->acked, err);
}
if (recv_data != NULL) {
if(flags & TCP_PSH) {
recv_data->flags |= PBUF_FLAG_PUSH;
}
/* Notify application that data has been received. */
TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
/* If the upper layer can't receive this data, store it */
if (err != ERR_OK) {
pcb->refused_data = recv_data;
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
}
}
/* If a FIN segment was received, we call the callback
function with a NULL buffer to indicate EOF. */
if (recv_flags & TF_GOT_FIN) {
TCP_EVENT_RECV(pcb, NULL, ERR_OK, err);
}
/* If there were no errors, we try to send something out. */
if (err == ERR_OK) {
tcp_output(pcb);
}
}
}
/* give up our reference to inseg.p */
if (inseg.p != NULL)
{
pbuf_free(inseg.p);
inseg.p = NULL;
}
#if TCP_INPUT_DEBUG
#if TCP_DEBUG
tcp_debug_print_state(pcb->state);
#endif /* TCP_DEBUG */
#endif /* TCP_INPUT_DEBUG */
} else {
/* If no matching PCB was found, send a TCP RST (reset) to the
sender. */
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
TCP_STATS_INC(tcp.proterr);
TCP_STATS_INC(tcp.drop);
tcp_rst(ackno, seqno + tcplen,
&(iphdr->dest), &(iphdr->src),
tcphdr->dest, tcphdr->src);
}
pbuf_free(p);
}
LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
PERF_STOP("tcp_input");
}
/**
* 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.
*
* @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)
{
err_t err;
#if TCP_DEBUG
LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
tcp_debug_print_state(pcb->state);
#endif /* TCP_DEBUG */
switch (pcb->state) {
/* 若TCP在CLOSE状态，即tcp_new()之后从未使用过 */
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;
/* 从tcp_bound_pcbs链表上删除(如果已经调用tcp_bind()的话) */
TCP_RMV(&tcp_bound_pcbs, pcb);
/* 释放TCP控制所占内存 */
memp_free(MEMP_TCP_PCB, pcb);
pcb = NULL;
break;
case LISTEN:
err = ERR_OK;
/* 从LISTEN链表上删除，并发送可能存在的delayed ACKs */
tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs.pcbs, pcb);
/* 释放LISTEN类型的TCP控制块 */
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:
/* 构造FIN报文，主动关闭 */
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpattemptfails();
/* 进入FIN_WAIT_1状态 */
pcb->state = FIN_WAIT_1;
}
break;
case ESTABLISHED:
/* 构造FIN报文，主动关闭 */
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
/* 进入FIN_WAIT_1状态 */
pcb->state = FIN_WAIT_1;
}
break;
/* 被动关闭，收到对方的FIN后，构造FIN关闭另一个方向传输 */
case CLOSE_WAIT:
err = tcp_send_ctrl(pcb, TCP_FIN);
if (err == ERR_OK) {
snmp_inc_tcpestabresets();
/* 进入LAST_ACK状态 */
pcb->state = LAST_ACK;
}
break;
/* 其他状态，用TCP定时器函数实现 */
default:
/* Has already been closed, do nothing. */
err = ERR_OK;
pcb = NULL;
break;
}
/* 发送TCP控制块中剩余的报文段，包括FIN报文 */
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 when tcp_close returns. */
tcp_output(pcb);
}
return err;
}