qemu

filter-buffer.c (6150B)

---

 /*
  * 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"
 
 OBJECT_DECLARE_SIMPLE_TYPE(FilterBufferState, FILTER_BUFFER)
 
 struct FilterBufferState {
     NetFilterState parent_obj;
 
     NetQueue *incoming_queue;
     uint32_t interval;
     QEMUTimer release_timer;
 };
 
 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_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);
     uint32_t value;
 
     if (!visit_type_uint32(v, name, &value, errp)) {
         return;
     }
     if (!value) {
         error_setg(errp, "Property '%s.%s' requires a positive value",
                    object_get_typename(obj), name);
         return;
     }
     s->interval = value;
 }
 
 static void filter_buffer_class_init(ObjectClass *oc, void *data)
 {
     NetFilterClass *nfc = NETFILTER_CLASS(oc);
 
     object_class_property_add(oc, "interval", "uint32",
                               filter_buffer_get_interval,
                               filter_buffer_set_interval, NULL, NULL);
 
     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 const TypeInfo filter_buffer_info = {
     .name = TYPE_FILTER_BUFFER,
     .parent = TYPE_NETFILTER,
     .class_init = filter_buffer_class_init,
     .instance_size = sizeof(FilterBufferState),
 };
 
 static void register_types(void)
 {
     type_register_static(&filter_buffer_info);
 }
 
 type_init(register_types);