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tcp: changed accept handling to be done internally: the application does not have to call tcp_accepted() any more. Instead, when delaying accept (e.g. sockets do), call tcp_backlog_delayed()/tcp_backlog_accepted() (fixes bug #46696)

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This commit is contained in:
sg
2016-03-22 07:30:44 +01:00
parent a1c78ea7bf
commit dd80759bb9
9 changed files with 176 additions and 86 deletions
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100
src/core/tcp.c
View File

@@ -147,6 +147,78 @@ tcp_tmr(void)
}
}
#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;
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
/** 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);
if (pcb->listener != NULL) {
pcb->listener->accepts_pending++;
LWIP_ASSERT("accepts_pending != 0", pcb->listener->accepts_pending != 0);
}
}
/** 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);
if (pcb->listener != NULL) {
LWIP_ASSERT("accepts_pending != 0", pcb->listener->accepts_pending != 0);
pcb->listener->accepts_pending--;
}
}
#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
@@ -217,6 +289,7 @@ tcp_close_shutdown(struct tcp_pcb *pcb, u8_t rst_on_unacked_data)
case LISTEN:
err = ERR_OK;
tcp_pcb_remove(&tcp_listen_pcbs.pcbs, pcb);
tcp_listen_closed(pcb);
memp_free(MEMP_TCP_PCB_LISTEN, pcb);
pcb = NULL;
break;
@@ -230,6 +303,7 @@ tcp_close_shutdown(struct tcp_pcb *pcb, u8_t rst_on_unacked_data)
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;
}
@@ -1586,9 +1660,10 @@ tcp_err(struct tcp_pcb *pcb, tcp_err_fn err)
void
tcp_accept(struct tcp_pcb *pcb, tcp_accept_fn accept)
{
/* This function is allowed to be called for both listen pcbs and
connection pcbs. */
pcb->accept = accept;
if (pcb->state == LISTEN) {
struct tcp_pcb_listen *lpcb = (struct tcp_pcb_listen*)pcb;
lpcb->accept = accept;
}
}
#endif /* LWIP_CALLBACK_API */
@@ -1628,22 +1703,9 @@ tcp_pcb_purge(struct tcp_pcb *pcb)
#if TCP_LISTEN_BACKLOG
if (pcb->state == SYN_RCVD) {
/* Need to find the corresponding listen_pcb and decrease its accepts_pending */
struct tcp_pcb_listen *lpcb;
LWIP_ASSERT("tcp_pcb_purge: pcb->state == SYN_RCVD but tcp_listen_pcbs is NULL",
tcp_listen_pcbs.listen_pcbs != NULL);
for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
if ((lpcb->local_port == pcb->local_port) &&
(IP_IS_V6_VAL(pcb->local_ip) == IP_IS_V6_VAL(lpcb->local_ip)) &&
(ip_addr_isany(&lpcb->local_ip) ||
ip_addr_cmp(&pcb->local_ip, &lpcb->local_ip))) {
/* port and address of the listen pcb match the timed-out pcb */
LWIP_ASSERT("tcp_pcb_purge: listen pcb does not have accepts pending",
lpcb->accepts_pending > 0);
lpcb->accepts_pending--;
break;
}
}
tcp_backlog_accepted(pcb);
/* prevent executing this again: */
pcb->listener = NULL;
}
#endif /* TCP_LISTEN_BACKLOG */

20
src/core/tcp_in.c
View File

@@ -579,9 +579,9 @@ tcp_listen_input(struct tcp_pcb_listen *pcb)
npcb->rcv_ann_right_edge = npcb->rcv_nxt;
npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
npcb->callback_arg = pcb->callback_arg;
#if LWIP_CALLBACK_API
npcb->accept = pcb->accept;
#endif /* LWIP_CALLBACK_API */
#if LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG
npcb->listener = pcb;
#endif /* LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG */
/* inherit socket options */
npcb->so_options = pcb->so_options & SOF_INHERITED;
/* Register the new PCB so that we can begin receiving segments
@@ -784,10 +784,18 @@ tcp_process(struct tcp_pcb *pcb)
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);
LWIP_ASSERT("pcb->listener->accept != NULL",
(pcb->listener == NULL) || (pcb->listener->accept != NULL));
if (pcb->listener == NULL) {
/* listen pcb might be closed by now */
err = ERR_VAL;
} else
#endif
/* Call the accept function. */
TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
{
tcp_backlog_accepted(pcb);
/* 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. */