qemu/net/filter-buffer.c
Markus Armbruster d2623129a7 qom: Drop parameter @errp of object_property_add() & friends
The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
2020-05-15 07:07:58 +02:00

212 lines
6.2 KiB
C

/*
* Copyright (c) 2015 FUJITSU LIMITED
* Author: Yang Hongyang <yanghy@cn.fujitsu.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "net/filter.h"
#include "net/queue.h"
#include "qapi/error.h"
#include "qemu/timer.h"
#include "qemu/iov.h"
#include "qapi/qapi-builtin-visit.h"
#include "qapi/qmp/qerror.h"
#include "qom/object.h"
#define TYPE_FILTER_BUFFER "filter-buffer"
#define FILTER_BUFFER(obj) \
OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)
typedef struct FilterBufferState {
NetFilterState parent_obj;
NetQueue *incoming_queue;
uint32_t interval;
QEMUTimer release_timer;
} FilterBufferState;
static void filter_buffer_flush(NetFilterState *nf)
{
FilterBufferState *s = FILTER_BUFFER(nf);
if (!qemu_net_queue_flush(s->incoming_queue)) {
/* Unable to empty the queue, purge remaining packets */
qemu_net_queue_purge(s->incoming_queue, nf->netdev);
}
}
static void filter_buffer_release_timer(void *opaque)
{
NetFilterState *nf = opaque;
FilterBufferState *s = FILTER_BUFFER(nf);
/*
* Note: filter_buffer_flush() drops packets that can't be sent
* TODO: We should leave them queued. But currently there's no way
* for the next filter or receiver to notify us that it can receive
* more packets.
*/
filter_buffer_flush(nf);
/* Timer rearmed to fire again in s->interval microseconds. */
timer_mod(&s->release_timer,
qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
}
/* filter APIs */
static ssize_t filter_buffer_receive_iov(NetFilterState *nf,
NetClientState *sender,
unsigned flags,
const struct iovec *iov,
int iovcnt,
NetPacketSent *sent_cb)
{
FilterBufferState *s = FILTER_BUFFER(nf);
/*
* We return size when buffer a packet, the sender will take it as
* a already sent packet, so sent_cb should not be called later.
*
* FIXME: Even if the guest can't receive packets for some reasons,
* the filter can still accept packets until its internal queue is full.
* For example:
* For some reason, receiver could not receive more packets
* (.can_receive() returns false). Without a filter, at most one packet
* will be queued in incoming queue and sender's poll will be disabled
* unit its sent_cb() was called. With a filter, it will keep receiving
* the packets without caring about the receiver. This is suboptimal.
* May need more thoughts (e.g keeping sent_cb).
*/
qemu_net_queue_append_iov(s->incoming_queue, sender, flags,
iov, iovcnt, NULL);
return iov_size(iov, iovcnt);
}
static void filter_buffer_cleanup(NetFilterState *nf)
{
FilterBufferState *s = FILTER_BUFFER(nf);
if (s->interval) {
timer_del(&s->release_timer);
}
/* flush packets */
if (s->incoming_queue) {
filter_buffer_flush(nf);
g_free(s->incoming_queue);
}
}
static void filter_buffer_setup_timer(NetFilterState *nf)
{
FilterBufferState *s = FILTER_BUFFER(nf);
if (s->interval) {
timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
filter_buffer_release_timer, nf);
/* Timer armed to fire in s->interval microseconds. */
timer_mod(&s->release_timer,
qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
}
}
static void filter_buffer_setup(NetFilterState *nf, Error **errp)
{
FilterBufferState *s = FILTER_BUFFER(nf);
/*
* We may want to accept zero interval when VM FT solutions like MC
* or COLO use this filter to release packets on demand.
*/
if (!s->interval) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
"a non-zero interval");
return;
}
s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
filter_buffer_setup_timer(nf);
}
static void filter_buffer_status_changed(NetFilterState *nf, Error **errp)
{
FilterBufferState *s = FILTER_BUFFER(nf);
if (!nf->on) {
if (s->interval) {
timer_del(&s->release_timer);
}
filter_buffer_flush(nf);
} else {
filter_buffer_setup_timer(nf);
}
}
static void filter_buffer_class_init(ObjectClass *oc, void *data)
{
NetFilterClass *nfc = NETFILTER_CLASS(oc);
nfc->setup = filter_buffer_setup;
nfc->cleanup = filter_buffer_cleanup;
nfc->receive_iov = filter_buffer_receive_iov;
nfc->status_changed = filter_buffer_status_changed;
}
static void filter_buffer_get_interval(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
FilterBufferState *s = FILTER_BUFFER(obj);
uint32_t value = s->interval;
visit_type_uint32(v, name, &value, errp);
}
static void filter_buffer_set_interval(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
FilterBufferState *s = FILTER_BUFFER(obj);
Error *local_err = NULL;
uint32_t value;
visit_type_uint32(v, name, &value, &local_err);
if (local_err) {
goto out;
}
if (!value) {
error_setg(&local_err, "Property '%s.%s' requires a positive value",
object_get_typename(obj), name);
goto out;
}
s->interval = value;
out:
error_propagate(errp, local_err);
}
static void filter_buffer_init(Object *obj)
{
object_property_add(obj, "interval", "uint32",
filter_buffer_get_interval,
filter_buffer_set_interval, NULL, NULL);
}
static const TypeInfo filter_buffer_info = {
.name = TYPE_FILTER_BUFFER,
.parent = TYPE_NETFILTER,
.class_init = filter_buffer_class_init,
.instance_init = filter_buffer_init,
.instance_size = sizeof(FilterBufferState),
};
static void register_types(void)
{
type_register_static(&filter_buffer_info);
}
type_init(register_types);