listener.c

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Author : Nick Mathewson
Date : 2010-02-18 00:27:35
Hash : cb52838f
Message : When working without a current event base, don't try to use IOCP listeners This fixes a bug turned up with the http unit tests, where we create the evhttp object using an implicit (NULL) event_base. This failed pretty badly when we tried to use IOCP-based listeners. We could hunt for the current base from inside listener.c in the future, or get the iocp base some other way, but for now this is probably the safest solution.
listener.c
/*
 * Copyright (c) 2009 Niels Provos, Nick Mathewson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>

#include "event-config.h"

#ifdef WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#include <mswsock.h>
#endif
#include <errno.h>
#ifdef _EVENT_HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef _EVENT_HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef _EVENT_HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <event2/listener.h>
#include <event2/util.h>
#include <event2/event.h>
#include <event2/event_struct.h>
#include "mm-internal.h"
#include "util-internal.h"
#include "log-internal.h"
#ifdef WIN32
#include "iocp-internal.h"
#include "defer-internal.h"
#endif

struct evconnlistener_ops {
	int (*enable)(struct evconnlistener *);
	int (*disable)(struct evconnlistener *);
	void (*destroy)(struct evconnlistener *);
	evutil_socket_t (*getfd)(struct evconnlistener *);
	struct event_base *(*getbase)(struct evconnlistener *);
};

struct evconnlistener {
	const struct evconnlistener_ops *ops;
	evconnlistener_cb cb;
	void *user_data;
	unsigned flags;
};

struct evconnlistener_event {
	struct evconnlistener base;
	struct event listener;
};

#ifdef WIN32
struct evconnlistener_iocp {
	struct evconnlistener base;
	evutil_socket_t fd;
	struct event_base *event_base;
	struct event_iocp_port *port;
	CRITICAL_SECTION lock;
	int n_accepting;
	struct accepting_socket **accepting;
};
#endif

struct evconnlistener *
evconnlistener_new_async(struct event_base *base,
    evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
    evutil_socket_t fd); /* XXXX export this? */

static int event_listener_enable(struct evconnlistener *);
static int event_listener_disable(struct evconnlistener *);
static void event_listener_destroy(struct evconnlistener *);
static evutil_socket_t event_listener_getfd(struct evconnlistener *);
static struct event_base *event_listener_getbase(struct evconnlistener *);

static const struct evconnlistener_ops evconnlistener_event_ops = {
	event_listener_enable,
	event_listener_disable,
	event_listener_destroy,
	event_listener_getfd,
	event_listener_getbase
};

static void listener_read_cb(evutil_socket_t, short, void *);

struct evconnlistener *
evconnlistener_new(struct event_base *base,
    evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
    evutil_socket_t fd)
{
	struct evconnlistener_event *lev;

#ifdef WIN32
	if (base && event_base_get_iocp(base)) {
		const struct win32_extension_fns *ext =
			event_get_win32_extension_fns();
		if (ext->AcceptEx && ext->GetAcceptExSockaddrs)
			return evconnlistener_new_async(base, cb, ptr, flags,
				backlog, fd);
	}
#endif

	if (backlog > 0) {
		if (listen(fd, backlog) < 0)
			return NULL;
	} else if (backlog < 0) {
		if (listen(fd, 128) < 0)
			return NULL;
	}

	lev = mm_calloc(1, sizeof(struct evconnlistener_event));
	if (!lev)
		return NULL;

	lev->base.ops = &evconnlistener_event_ops;
	lev->base.cb = cb;
	lev->base.user_data = ptr;
	lev->base.flags = flags;

	event_assign(&lev->listener, base, fd, EV_READ|EV_PERSIST,
	    listener_read_cb, lev);
	evconnlistener_enable(&lev->base);

	return &lev->base;
}

struct evconnlistener *
evconnlistener_new_bind(struct event_base *base, evconnlistener_cb cb,
    void *ptr, unsigned flags, int backlog, const struct sockaddr *sa,
    int socklen)
{
	struct evconnlistener *listener;
	evutil_socket_t fd;
	int on = 1;
	int family = sa ? sa->sa_family : AF_UNSPEC;

	if (backlog == 0)
		return NULL;

	fd = socket(family, SOCK_STREAM, 0);
	if (fd == -1)
		return NULL;

	if (evutil_make_socket_nonblocking(fd) < 0) {
		EVUTIL_CLOSESOCKET(fd);
		return NULL;
	}

	if (flags & LEV_OPT_CLOSE_ON_EXEC) {
		if (evutil_make_socket_closeonexec(fd) < 0) {
			EVUTIL_CLOSESOCKET(fd);
			return NULL;
		}
	}

	setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void*)&on, sizeof(on));
	if (flags & LEV_OPT_REUSEABLE) {
		evutil_make_listen_socket_reuseable(fd);
	}

	if (sa) {
		if (bind(fd, sa, socklen)<0) {
			EVUTIL_CLOSESOCKET(fd);
			return NULL;
		}
	}

	listener = evconnlistener_new(base, cb, ptr, flags, backlog, fd);
	if (!listener) {
		EVUTIL_CLOSESOCKET(fd);
		return NULL;				
	}

	return listener;
}

void
evconnlistener_free(struct evconnlistener *lev)
{
	lev->ops->destroy(lev);
	mm_free(lev);
}

static void
event_listener_destroy(struct evconnlistener *lev)
{
	struct evconnlistener_event *lev_e =
	    EVUTIL_UPCAST(lev, struct evconnlistener_event, base);

	event_del(&lev_e->listener);
	if (lev->flags & LEV_OPT_CLOSE_ON_FREE)
		EVUTIL_CLOSESOCKET(event_get_fd(&lev_e->listener));
	event_debug_unassign(&lev_e->listener);
}

int
evconnlistener_enable(struct evconnlistener *lev)
{
	return lev->ops->enable(lev);
}

int
evconnlistener_disable(struct evconnlistener *lev)
{
	return lev->ops->disable(lev);
}

static int
event_listener_enable(struct evconnlistener *lev)
{
	struct evconnlistener_event *lev_e =
	    EVUTIL_UPCAST(lev, struct evconnlistener_event, base);
	return event_add(&lev_e->listener, NULL);
}

static int
event_listener_disable(struct evconnlistener *lev)
{
	struct evconnlistener_event *lev_e =
	    EVUTIL_UPCAST(lev, struct evconnlistener_event, base);
	return event_del(&lev_e->listener);
}

evutil_socket_t
evconnlistener_get_fd(struct evconnlistener *lev)
{
	return lev->ops->getfd(lev);
}

static evutil_socket_t
event_listener_getfd(struct evconnlistener *lev)
{
	struct evconnlistener_event *lev_e =
	    EVUTIL_UPCAST(lev, struct evconnlistener_event, base);
	return event_get_fd(&lev_e->listener);
}

struct event_base *
evconnlistener_get_base(struct evconnlistener *lev)
{
	return lev->ops->getbase(lev);
}

static struct event_base *
event_listener_getbase(struct evconnlistener *lev)
{
	struct evconnlistener_event *lev_e =
	    EVUTIL_UPCAST(lev, struct evconnlistener_event, base);
	return event_get_base(&lev_e->listener);
}

static void
listener_read_cb(evutil_socket_t fd, short what, void *p)
{
	struct evconnlistener *lev = p;
	int err;
	while (1) {
		struct sockaddr_storage ss;
		socklen_t socklen = sizeof(ss);

		evutil_socket_t new_fd = accept(fd, (struct sockaddr*)&ss, &socklen);
		if (new_fd < 0)
			break;

		if (!(lev->flags & LEV_OPT_LEAVE_SOCKETS_BLOCKING))
			evutil_make_socket_nonblocking(new_fd);

		lev->cb(lev, new_fd, (struct sockaddr*)&ss, (int)socklen,
		    lev->user_data);
	}
	err = evutil_socket_geterror(fd);
	if (EVUTIL_ERR_ACCEPT_RETRIABLE(err))
		return;
	event_sock_warn(fd, "Error from accept() call");
}

#ifdef WIN32
struct accepting_socket {
	CRITICAL_SECTION lock;
	struct event_overlapped overlapped;
	SOCKET s;
	struct deferred_cb deferred;
	struct evconnlistener_iocp *lev;
	ev_uint8_t buflen;
	ev_uint8_t family;
	unsigned free_on_cb:1;
	char addrbuf[1];
};

static void accepted_socket_cb(struct event_overlapped *o, ev_uintptr_t key,
    ev_ssize_t n, int ok);
static void accepted_socket_invoke_user_cb(struct deferred_cb *cb, void *arg);

static struct accepting_socket *
new_accepting_socket(struct evconnlistener_iocp *lev, int family)
{
	struct accepting_socket *res;
	int addrlen;
	int buflen;

	if (family == AF_INET)
		addrlen = sizeof(struct sockaddr_in);
	else if (family == AF_INET6)
		addrlen = sizeof(struct sockaddr_in6);
	else
		return NULL;
	buflen = (addrlen+16)*2;

	res = mm_calloc(1,sizeof(struct accepting_socket)-1+buflen);
	if (!res)
		return NULL;

	event_overlapped_init(&res->overlapped, accepted_socket_cb);
	res->s = INVALID_SOCKET;
	res->lev = lev;
	res->buflen = buflen;
	res->family = family;

	event_deferred_cb_init(&res->deferred,
		accepted_socket_invoke_user_cb, res);

	InitializeCriticalSectionAndSpinCount(&res->lock, 1000);

	return res;
}

static void
free_and_unlock_accepting_socket(struct accepting_socket *as)
{
	/* requires lock. */
	if (as->s != INVALID_SOCKET)
		closesocket(as->s);

	LeaveCriticalSection(&as->lock);
	DeleteCriticalSection(&as->lock);
	mm_free(as);
}

static int
start_accepting(struct accepting_socket *as)
{
	/* requires lock */
	const struct win32_extension_fns *ext = event_get_win32_extension_fns();
	DWORD pending = 0;
	SOCKET s = socket(as->family, SOCK_STREAM, 0);
	if (s == INVALID_SOCKET)
		return -1;

	setsockopt(s, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
	    (char *)&as->lev->fd, sizeof(&as->lev->fd));

	if (!(as->lev->base.flags & LEV_OPT_LEAVE_SOCKETS_BLOCKING))
		evutil_make_socket_nonblocking(s);

	if (event_iocp_port_associate(as->lev->port, s, 1) < 0) {
		closesocket(s);
		return -1;
	}

	as->s = s;

	if (ext->AcceptEx(as->lev->fd, s, as->addrbuf, 0,
		as->buflen/2, as->buflen/2, &pending, &as->overlapped.overlapped))
	{
		/* Immediate success! */
		accepted_socket_cb(&as->overlapped, 1, 0, 1);
	} else {
		int err = WSAGetLastError();
		if (err != ERROR_IO_PENDING) {
			event_warnx("AcceptEx: %s", evutil_socket_error_to_string(err));
			return -1;
		}
	}

	return 0;
}

static void
stop_accepting(struct accepting_socket *as)
{
	/* requires lock. */
	SOCKET s = as->s;
	as->s = INVALID_SOCKET;
	closesocket(s);
}

static void
accepted_socket_invoke_user_cb(struct deferred_cb *cb, void *arg)
{
	struct accepting_socket *as = arg;

	struct sockaddr *sa_local=NULL, *sa_remote=NULL;
	int socklen_local=0, socklen_remote=0;
	const struct win32_extension_fns *ext = event_get_win32_extension_fns();

	EVUTIL_ASSERT(ext->GetAcceptExSockaddrs);

	EnterCriticalSection(&as->lock);
	if (as->free_on_cb) {
		free_and_unlock_accepting_socket(as);
		return;
	}

	ext->GetAcceptExSockaddrs(
		as->addrbuf, 0, as->buflen/2, as->buflen/2,
		&sa_local, &socklen_local, &sa_remote, &socklen_remote);

	as->lev->base.cb(&as->lev->base, as->s, sa_remote,
	    socklen_remote, as->lev->base.user_data);

	as->s = INVALID_SOCKET;

	start_accepting(as); /* XXXX handle error */
	LeaveCriticalSection(&as->lock);
}

static void
accepted_socket_cb(struct event_overlapped *o, ev_uintptr_t key, ev_ssize_t n, int ok)
{
	struct accepting_socket *as =
	    EVUTIL_UPCAST(o, struct accepting_socket, overlapped);

	EnterCriticalSection(&as->lock);
	if (ok) {
		/* XXXX Don't do this if some EV_MT flag is set. */
		event_deferred_cb_schedule(
			event_base_get_deferred_cb_queue(as->lev->event_base),
			&as->deferred);
		LeaveCriticalSection(&as->lock);
	} else if (as->free_on_cb) {
		free_and_unlock_accepting_socket(as);
	} else if (as->s == INVALID_SOCKET) {
		/* This is okay; we were disabled by iocp_listener_disable. */
		LeaveCriticalSection(&as->lock);
	} else {
		/* Some error on accept that we couldn't actually handle. */
		event_sock_warn(as->s, "Unexpected error on AcceptEx");
		LeaveCriticalSection(&as->lock);
		/* XXXX recover better. */
	}
}

static int
iocp_listener_enable(struct evconnlistener *lev)
{
	int i;
	struct evconnlistener_iocp *lev_iocp =
	    EVUTIL_UPCAST(lev, struct evconnlistener_iocp, base);

	EnterCriticalSection(&lev_iocp->lock);
	for (i = 0; i < lev_iocp->n_accepting; ++i) {
		struct accepting_socket *as = lev_iocp->accepting[i];
		if (!as)
			continue;
		EnterCriticalSection(&as->lock);
		if (!as->free_on_cb && as->s == INVALID_SOCKET)
			start_accepting(as); /* XXXX handle error */
		LeaveCriticalSection(&as->lock);
	}
	LeaveCriticalSection(&lev_iocp->lock);
	return 0;
}

static int
iocp_listener_disable_impl(struct evconnlistener *lev, int shutdown)
{
	int i;
	struct evconnlistener_iocp *lev_iocp =
	    EVUTIL_UPCAST(lev, struct evconnlistener_iocp, base);

	EnterCriticalSection(&lev_iocp->lock);
	for (i = 0; i < lev_iocp->n_accepting; ++i) {
		struct accepting_socket *as = lev_iocp->accepting[i];
		if (!as)
			continue;
		EnterCriticalSection(&as->lock);
		if (!as->free_on_cb && as->s != INVALID_SOCKET) {
			if (shutdown)
				as->free_on_cb = 1;
			stop_accepting(as);
		}
		LeaveCriticalSection(&as->lock);
	}
	LeaveCriticalSection(&lev_iocp->lock);
	return 0;
}

static int
iocp_listener_disable(struct evconnlistener *lev)
{
	return iocp_listener_disable_impl(lev,0);
}
static void
iocp_listener_destroy(struct evconnlistener *lev)
{
	iocp_listener_disable_impl(lev,1);
}

static evutil_socket_t
iocp_listener_getfd(struct evconnlistener *lev)
{
	struct evconnlistener_iocp *lev_iocp =
	    EVUTIL_UPCAST(lev, struct evconnlistener_iocp, base);
	return lev_iocp->fd;
}
static struct event_base *
iocp_listener_getbase(struct evconnlistener *lev)
{
	struct evconnlistener_iocp *lev_iocp =
	    EVUTIL_UPCAST(lev, struct evconnlistener_iocp, base);
	return lev_iocp->event_base;
}

static const struct evconnlistener_ops evconnlistener_iocp_ops = {
	iocp_listener_enable,
	iocp_listener_disable,
	iocp_listener_destroy,
	iocp_listener_getfd,
	iocp_listener_getbase
};

/* XXX define some way to override this. */
#define N_SOCKETS_PER_LISTENER 4

struct evconnlistener *
evconnlistener_new_async(struct event_base *base,
    evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
    evutil_socket_t fd)
{
	struct sockaddr_storage ss;
	int socklen = sizeof(ss);
	struct evconnlistener_iocp *lev;
	int i;

	if (!base || !event_base_get_iocp(base))
		goto err;

	/* XXXX duplicate code */
	if (backlog > 0) {
		if (listen(fd, backlog) < 0)
			goto err;
	} else if (backlog < 0) {
		if (listen(fd, 128) < 0)
			goto err;
	}
	if (getsockname(fd, (struct sockaddr*)&ss, &socklen)) {
		event_sock_warn(fd, "getsockname");
		goto err;
	}
	lev = mm_calloc(1, sizeof(struct evconnlistener_event));
	if (!lev) {
		event_warn("calloc");
		goto err;
	}
	lev->base.ops = &evconnlistener_iocp_ops;
	lev->base.cb = cb;
	lev->base.user_data = ptr;
	lev->base.flags = flags;

	lev->port = event_base_get_iocp(base);
	lev->fd = fd;
	lev->event_base = base;

	if (event_iocp_port_associate(lev->port, fd, 1) < 0)
		goto err_free_lev;

	InitializeCriticalSectionAndSpinCount(&lev->lock, 1000);

	lev->n_accepting = N_SOCKETS_PER_LISTENER;
	lev->accepting = mm_calloc(lev->n_accepting,
	    sizeof(struct accepting_socket *));
	if (!lev->accepting) {
		event_warn("calloc");
		goto err_delete_lock;
	}
	for (i = 0; i < lev->n_accepting; ++i) {
		lev->accepting[i] = new_accepting_socket(lev, ss.ss_family);
		if (!lev->accepting[i]) {
			event_warnx("Couldn't create accepting socket");
			goto err_free_accepting;
		}
		if (start_accepting(lev->accepting[i]) < 0) {
			event_warnx("Couldn't start accepting on socket");
			EnterCriticalSection(&lev->accepting[i]->lock);
			free_and_unlock_accepting_socket(lev->accepting[i]);
			goto err_free_accepting;
		}
	}

	return &lev->base;

err_free_accepting:
	mm_free(lev->accepting);
	/* XXXX free the other elements. */
err_delete_lock:
	DeleteCriticalSection(&lev->lock);
err_free_lev:
	mm_free(lev);
err:
	/* Don't close the fd, it is caller's responsibility. */
	return NULL;
}

#endif
kc3-lang/libevent/listener.c

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kc3-lang/libevent /listener.c
