luo980/libuv
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

windows: abort accept requests when a shared tcp server is closed

Browse Source 
Just closing the listening socket handle does not cancel AcceptEx
operations when another handle is keeping the underlying socket
open. Thus the AcceptEx operations have to be explicitly canceled
in uv_tcp_close.
This commit is contained in:
Bert Belder 2012-06-20 03:32:55 +02:00
parent b496c1221c
commit 6e8eb33249
1 changed files with 74 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
src/win/tcp.c
View File

@ -28,7 +28,6 @@
#include "req-inl.h"
/*
* Threshold of active tcp streams for which to preallocate tcp read buffers.
* (Due to node slab allocator performing poorly under this pattern,
@ -1292,31 +1291,88 @@ int uv_tcp_simultaneous_accepts(uv_tcp_t* handle, int enable) {
}
void uv_tcp_close(uv_loop_t* loop, uv_tcp_t* tcp) {
static int uv_tcp_try_cancel_io(uv_tcp_t* tcp) {
SOCKET socket = tcp->socket;
int non_ifs_lsp;
/* Check if we have any non-IFS LSPs stacked on top of TCP */
non_ifs_lsp = (tcp->flags & UV_HANDLE_IPV6) ? uv_tcp_non_ifs_lsp_ipv6 :
uv_tcp_non_ifs_lsp_ipv4;
/* If there are non-ifs LSPs then try to obtain a base handle for the */
/* socket. This will always fail on Windows XP/3k. */
if (non_ifs_lsp) {
DWORD bytes;
if (WSAIoctl(socket,
SIO_BASE_HANDLE,
NULL,
0,
&socket,
sizeof socket,
&bytes,
NULL,
NULL) != 0) {
/* Failed. We can't do CancelIo. */
return -1;
}
}
assert(socket != 0 && socket != INVALID_SOCKET);
if (!CancelIo((HANDLE) socket)) {
return -1;
}
/* It worked. */
return 0;
}
void uv_tcp_close(uv_loop_t* loop, uv_tcp_t* tcp) {
int close_socket = 1;
/*
* In order for winsock to do a graceful close there must not be
* any pending reads.
*/
if (tcp->flags & UV_HANDLE_READ_PENDING) {
/* Just do shutdown on non-shared sockets, which ensures graceful close. */
/* In order for winsock to do a graceful close there must not be any */
/* any pending reads, or the socket must be shut down for writing */
if (!(tcp->flags & UV_HANDLE_SHARED_TCP_SOCKET)) {
/* Just do shutdown on non-shared sockets, which ensures graceful close. */
shutdown(tcp->socket, SD_SEND);
tcp->flags |= UV_HANDLE_SHUT;
} else {
/* Check if we have any non-IFS LSPs stacked on top of TCP */
non_ifs_lsp = (tcp->flags & UV_HANDLE_IPV6) ? uv_tcp_non_ifs_lsp_ipv6 :
uv_tcp_non_ifs_lsp_ipv4;
if (!non_ifs_lsp) {
/*
* Shared socket with no non-IFS LSPs, request to cancel pending I/O.
* The socket will be closed inside endgame.
*/
CancelIo((HANDLE)tcp->socket);
close_socket = 0;
} else if (uv_tcp_try_cancel_io(tcp) == 0) {
/* In case of a shared socket, we try to cancel all outstanding I/O, */
/* If that works, don't close the socket yet - wait for the read req to */
/* return and close the socket in uv_tcp_endgame. */
close_socket = 0;
} else {
/* When cancelling isn't possible - which could happen when an LSP is */
/* present on an old Windows version, we will have to close the socket */
/* with a read pending. That is not nice because trailing sent bytes */
/* may not make it to the other side. */
}
} else if ((tcp->flags & UV_HANDLE_SHARED_TCP_SOCKET) &&
tcp->accept_reqs != NULL) {
/* Under normal circumstances closesocket() will ensure that all pending */
/* accept reqs are canceled. However, when the socket is shared the */
/* presence of another reference to the socket in another process will */
/* keep the accept reqs going, so we have to ensure that these are */
/* canceled. */
if (uv_tcp_try_cancel_io(tcp) != 0) {
/* When cancellation is not possible, there is another option: we can */
/* close the incoming sockets, which will also cancel the accept */
/* operations. However this is not cool because we might inadvertedly */
/* close a socket that just accepted a new connection, which will */
/* cause the connection to be aborted. */
unsigned int i;
for (i = 0; i < uv_simultaneous_server_accepts; i++) {
uv_tcp_accept_t* req = &tcp->accept_reqs[i];
if (req->accept_socket != INVALID_SOCKET &&
!HasOverlappedIoCompleted(&req->overlapped)) {
closesocket(req->accept_socket);
req->accept_socket = INVALID_SOCKET;
}
}
}
}