net/filter-buffer.c

   1 /*
   2  * Copyright (c) 2015 FUJITSU LIMITED
   3  * Author: Yang Hongyang <yanghy@cn.fujitsu.com>
   4  *
   5  * This work is licensed under the terms of the GNU GPL, version 2 or
   6  * later.  See the COPYING file in the top-level directory.
   7  */
   8
   9 #include "net/filter.h"
  10 #include "net/queue.h"
  11 #include "qemu-common.h"
  12 #include "qemu/timer.h"
  13 #include "qemu/iov.h"
  14 #include "qapi/qmp/qerror.h"
  15 #include "qapi-visit.h"
  16 #include "qom/object.h"
  17
  18 #define TYPE_FILTER_BUFFER "filter-buffer"
  19
  20 #define FILTER_BUFFER(obj) \
  21     OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)
  22
  23 typedef struct FilterBufferState {
  24     NetFilterState parent_obj;
  25
  26     NetQueue *incoming_queue;
  27     uint32_t interval;
  28     QEMUTimer release_timer;
  29 } FilterBufferState;
  30
  31 static void filter_buffer_flush(NetFilterState *nf)
  32 {
  33     FilterBufferState *s = FILTER_BUFFER(nf);
  34
  35     if (!qemu_net_queue_flush(s->incoming_queue)) {
  36         /* Unable to empty the queue, purge remaining packets */
  37         qemu_net_queue_purge(s->incoming_queue, nf->netdev);
  38     }
  39 }
  40
  41 static void filter_buffer_release_timer(void *opaque)
  42 {
  43     NetFilterState *nf = opaque;
  44     FilterBufferState *s = FILTER_BUFFER(nf);
  45
  46     /*
  47      * Note: filter_buffer_flush() drops packets that can't be sent
  48      * TODO: We should leave them queued.  But currently there's no way
  49      * for the next filter or receiver to notify us that it can receive
  50      * more packets.
  51      */
  52     filter_buffer_flush(nf);
  53     /* Timer rearmed to fire again in s->interval microseconds. */
  54     timer_mod(&s->release_timer,
  55               qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
  56 }
  57
  58 /* filter APIs */
  59 static ssize_t filter_buffer_receive_iov(NetFilterState *nf,
  60                                          NetClientState *sender,
  61                                          unsigned flags,
  62                                          const struct iovec *iov,
  63                                          int iovcnt,
  64                                          NetPacketSent *sent_cb)
  65 {
  66     FilterBufferState *s = FILTER_BUFFER(nf);
  67
  68     /*
  69      * We return size when buffer a packet, the sender will take it as
  70      * a already sent packet, so sent_cb should not be called later.
  71      *
  72      * FIXME: Even if the guest can't receive packets for some reasons,
  73      * the filter can still accept packets until its internal queue is full.
  74      * For example:
  75      *   For some reason, receiver could not receive more packets
  76      * (.can_receive() returns zero). Without a filter, at most one packet
  77      * will be queued in incoming queue and sender's poll will be disabled
  78      * unit its sent_cb() was called. With a filter, it will keep receiving
  79      * the packets without caring about the receiver. This is suboptimal.
  80      * May need more thoughts (e.g keeping sent_cb).
  81      */
  82     qemu_net_queue_append_iov(s->incoming_queue, sender, flags,
  83                               iov, iovcnt, NULL);
  84     return iov_size(iov, iovcnt);
  85 }
  86
  87 static void filter_buffer_cleanup(NetFilterState *nf)
  88 {
  89     FilterBufferState *s = FILTER_BUFFER(nf);
  90
  91     if (s->interval) {
  92         timer_del(&s->release_timer);
  93     }
  94
  95     /* flush packets */
  96     if (s->incoming_queue) {
  97         filter_buffer_flush(nf);
  98         g_free(s->incoming_queue);
  99     }
 100 }
 101
 102 static void filter_buffer_setup(NetFilterState *nf, Error **errp)
 103 {
 104     FilterBufferState *s = FILTER_BUFFER(nf);
 105
 106     /*
 107      * We may want to accept zero interval when VM FT solutions like MC
 108      * or COLO use this filter to release packets on demand.
 109      */
 110     if (!s->interval) {
 111         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
 112                    "a non-zero interval");
 113         return;
 114     }
 115
 116     s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
 117     if (s->interval) {
 118         timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
 119                       filter_buffer_release_timer, nf);
 120         /* Timer armed to fire in s->interval microseconds. */
 121         timer_mod(&s->release_timer,
 122                   qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
 123     }
 124 }
 125
 126 static void filter_buffer_class_init(ObjectClass *oc, void *data)
 127 {
 128     NetFilterClass *nfc = NETFILTER_CLASS(oc);
 129
 130     nfc->setup = filter_buffer_setup;
 131     nfc->cleanup = filter_buffer_cleanup;
 132     nfc->receive_iov = filter_buffer_receive_iov;
 133 }
 134
 135 static void filter_buffer_get_interval(Object *obj, Visitor *v, void *opaque,
 136                                        const char *name, Error **errp)
 137 {
 138     FilterBufferState *s = FILTER_BUFFER(obj);
 139     uint32_t value = s->interval;
 140
 141     visit_type_uint32(v, &value, name, errp);
 142 }
 143
 144 static void filter_buffer_set_interval(Object *obj, Visitor *v, void *opaque,
 145                                        const char *name, Error **errp)
 146 {
 147     FilterBufferState *s = FILTER_BUFFER(obj);
 148     Error *local_err = NULL;
 149     uint32_t value;
 150
 151     visit_type_uint32(v, &value, name, &local_err);
 152     if (local_err) {
 153         goto out;
 154     }
 155     if (!value) {
 156         error_setg(&local_err, "Property '%s.%s' requires a positive value",
 157                    object_get_typename(obj), name);
 158         goto out;
 159     }
 160     s->interval = value;
 161
 162 out:
 163     error_propagate(errp, local_err);
 164 }
 165
 166 static void filter_buffer_init(Object *obj)
 167 {
 168     object_property_add(obj, "interval", "int",
 169                         filter_buffer_get_interval,
 170                         filter_buffer_set_interval, NULL, NULL, NULL);
 171 }
 172
 173 static const TypeInfo filter_buffer_info = {
 174     .name = TYPE_FILTER_BUFFER,
 175     .parent = TYPE_NETFILTER,
 176     .class_init = filter_buffer_class_init,
 177     .instance_init = filter_buffer_init,
 178     .instance_size = sizeof(FilterBufferState),
 179 };
 180
 181 static void register_types(void)
 182 {
 183     type_register_static(&filter_buffer_info);
 184 }
 185
 186 type_init(register_types);