From 019dd84af1e8e9bbdbbb6377c28950d31f05a77c Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Wed, 29 May 2019 01:29:48 +1000
Subject: [PATCH] extmod/modlwip: Register TCP close-timeout callback before
closing PCB.
In d5f0c87bb985ae344014dc2041fbaad5c522f638 this call to tcp_poll() was
added to put a timeout on closing TCP sockets. But after calling
tcp_close() the PCB may be freed and therefore invalid, so tcp_poll() can
not be used at that point. As a fix this commit calls tcp_poll() before
closing the TCP PCB. If the PCB is subsequently closed and freed by
tcp_close() or tcp_abort() then the PCB will not be on any active list and
the callback will not be executed, which is the desired behaviour (the
_lwip_tcp_close_poll() callback only needs to be called if the PCB remains
active for longer than the timeout).
---
extmod/modlwip.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/extmod/modlwip.c b/extmod/modlwip.c
index 06ed764b5..4127d21ad 100644
--- a/extmod/modlwip.c
+++ b/extmod/modlwip.c
@@ -1421,12 +1421,15 @@ STATIC mp_uint_t lwip_socket_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_
switch (socket->type) {
case MOD_NETWORK_SOCK_STREAM: {
+ if (socket->pcb.tcp->state != LISTEN) {
+ // Schedule a callback to abort the connection if it's not cleanly closed after
+ // the given timeout. The callback must be set before calling tcp_close since
+ // the latter may free the pcb; if it doesn't then the callback will be active.
+ tcp_poll(socket->pcb.tcp, _lwip_tcp_close_poll, MICROPY_PY_LWIP_TCP_CLOSE_TIMEOUT_MS / 500);
+ }
if (tcp_close(socket->pcb.tcp) != ERR_OK) {
DEBUG_printf("lwip_close: had to call tcp_abort()\n");
tcp_abort(socket->pcb.tcp);
- } else {
- // If connection not cleanly closed after timeout then abort the connection
- tcp_poll(socket->pcb.tcp, _lwip_tcp_close_poll, MICROPY_PY_LWIP_TCP_CLOSE_TIMEOUT_MS / 500);
}
break;
}
--
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