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 "qemu/osdep.h"
  10 #include "net/filter.h"
  11 #include "net/queue.h"
  12 #include "qapi/error.h"
  13 #include "qemu-common.h"
  14 #include "qemu/timer.h"
  15 #include "qemu/iov.h"
  16 #include "qapi/qmp/qerror.h"
  17 #include "qapi-visit.h"
  18 #include "qom/object.h"
  19
  20 #define TYPE_FILTER_BUFFER "filter-buffer"
  21
  22 #define FILTER_BUFFER(obj) \
  23     OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)
  24
  25 typedef struct FilterBufferState {
  26     NetFilterState parent_obj;
  27
  28     NetQueue *incoming_queue;
  29     uint32_t interval;
  30     QEMUTimer release_timer;
  31 } FilterBufferState;
  32
  33 static void filter_buffer_flush(NetFilterState *nf)
  34 {
  35     FilterBufferState *s = FILTER_BUFFER(nf);
  36
  37     if (!qemu_net_queue_flush(s->incoming_queue)) {
  38         /* Unable to empty the queue, purge remaining packets */
  39         qemu_net_queue_purge(s->incoming_queue, nf->netdev);
  40     }
  41 }
  42
  43 static void filter_buffer_release_timer(void *opaque)
  44 {
  45     NetFilterState *nf = opaque;
  46     FilterBufferState *s = FILTER_BUFFER(nf);
  47
  48     /*
  49      * Note: filter_buffer_flush() drops packets that can't be sent
  50      * TODO: We should leave them queued.  But currently there's no way
  51      * for the next filter or receiver to notify us that it can receive
  52      * more packets.
  53      */
  54     filter_buffer_flush(nf);
  55     /* Timer rearmed to fire again in s->interval microseconds. */
  56     timer_mod(&s->release_timer,
  57               qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
  58 }
  59
  60 /* filter APIs */
  61 static ssize_t filter_buffer_receive_iov(NetFilterState *nf,
  62                                          NetClientState *sender,
  63                                          unsigned flags,
  64                                          const struct iovec *iov,
  65                                          int iovcnt,
  66                                          NetPacketSent *sent_cb)
  67 {
  68     FilterBufferState *s = FILTER_BUFFER(nf);
  69
  70     /*
  71      * We return size when buffer a packet, the sender will take it as
  72      * a already sent packet, so sent_cb should not be called later.
  73      *
  74      * FIXME: Even if the guest can't receive packets for some reasons,
  75      * the filter can still accept packets until its internal queue is full.
  76      * For example:
  77      *   For some reason, receiver could not receive more packets
  78      * (.can_receive() returns zero). Without a filter, at most one packet
  79      * will be queued in incoming queue and sender's poll will be disabled
  80      * unit its sent_cb() was called. With a filter, it will keep receiving
  81      * the packets without caring about the receiver. This is suboptimal.
  82      * May need more thoughts (e.g keeping sent_cb).
  83      */
  84     qemu_net_queue_append_iov(s->incoming_queue, sender, flags,
  85                               iov, iovcnt, NULL);
  86     return iov_size(iov, iovcnt);
  87 }
  88
  89 static void filter_buffer_cleanup(NetFilterState *nf)
  90 {
  91     FilterBufferState *s = FILTER_BUFFER(nf);
  92
  93     if (s->interval) {
  94         timer_del(&s->release_timer);
  95     }
  96
  97     /* flush packets */
  98     if (s->incoming_queue) {
  99         filter_buffer_flush(nf);
 100         g_free(s->incoming_queue);
 101     }
 102 }
 103
 104 static void filter_buffer_setup_timer(NetFilterState *nf)
 105 {
 106     FilterBufferState *s = FILTER_BUFFER(nf);
 107
 108     if (s->interval) {
 109         timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
 110                       filter_buffer_release_timer, nf);
 111         /* Timer armed to fire in s->interval microseconds. */
 112         timer_mod(&s->release_timer,
 113                   qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
 114     }
 115 }
 116
 117 static void filter_buffer_setup(NetFilterState *nf, Error **errp)
 118 {
 119     FilterBufferState *s = FILTER_BUFFER(nf);
 120
 121     /*
 122      * We may want to accept zero interval when VM FT solutions like MC
 123      * or COLO use this filter to release packets on demand.
 124      */
 125     if (!s->interval) {
 126         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
 127                    "a non-zero interval");
 128         return;
 129     }
 130
 131     s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
 132     filter_buffer_setup_timer(nf);
 133 }
 134
 135 static void filter_buffer_status_changed(NetFilterState *nf, Error **errp)
 136 {
 137     FilterBufferState *s = FILTER_BUFFER(nf);
 138
 139     if (!nf->on) {
 140         if (s->interval) {
 141             timer_del(&s->release_timer);
 142         }
 143         filter_buffer_flush(nf);
 144     } else {
 145         filter_buffer_setup_timer(nf);
 146     }
 147 }
 148
 149 static void filter_buffer_class_init(ObjectClass *oc, void *data)
 150 {
 151     NetFilterClass *nfc = NETFILTER_CLASS(oc);
 152
 153     nfc->setup = filter_buffer_setup;
 154     nfc->cleanup = filter_buffer_cleanup;
 155     nfc->receive_iov = filter_buffer_receive_iov;
 156     nfc->status_changed = filter_buffer_status_changed;
 157 }
 158
 159 static void filter_buffer_get_interval(Object *obj, Visitor *v,
 160                                        const char *name, void *opaque,
 161                                        Error **errp)
 162 {
 163     FilterBufferState *s = FILTER_BUFFER(obj);
 164     uint32_t value = s->interval;
 165
 166     visit_type_uint32(v, name, &value, errp);
 167 }
 168
 169 static void filter_buffer_set_interval(Object *obj, Visitor *v,
 170                                        const char *name, void *opaque,
 171                                        Error **errp)
 172 {
 173     FilterBufferState *s = FILTER_BUFFER(obj);
 174     Error *local_err = NULL;
 175     uint32_t value;
 176
 177     visit_type_uint32(v, name, &value, &local_err);
 178     if (local_err) {
 179         goto out;
 180     }
 181     if (!value) {
 182         error_setg(&local_err, "Property '%s.%s' requires a positive value",
 183                    object_get_typename(obj), name);
 184         goto out;
 185     }
 186     s->interval = value;
 187
 188 out:
 189     error_propagate(errp, local_err);
 190 }
 191
 192 static void filter_buffer_init(Object *obj)
 193 {
 194     object_property_add(obj, "interval", "int",
 195                         filter_buffer_get_interval,
 196                         filter_buffer_set_interval, NULL, NULL, NULL);
 197 }
 198
 199 static const TypeInfo filter_buffer_info = {
 200     .name = TYPE_FILTER_BUFFER,
 201     .parent = TYPE_NETFILTER,
 202     .class_init = filter_buffer_class_init,
 203     .instance_init = filter_buffer_init,
 204     .instance_size = sizeof(FilterBufferState),
 205 };
 206
 207 static void register_types(void)
 208 {
 209     type_register_static(&filter_buffer_info);
 210 }
 211
 212 type_init(register_types);