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/timer.h"
  14 #include "qemu/iov.h"
  15 #include "qapi/qapi-builtin-visit.h"
  16 #include "qapi/qmp/qerror.h"
  17 #include "qom/object.h"
  18
  19 #define TYPE_FILTER_BUFFER "filter-buffer"
  20
  21 #define FILTER_BUFFER(obj) \
  22     OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)
  23
  24 typedef struct FilterBufferState {
  25     NetFilterState parent_obj;
  26
  27     NetQueue *incoming_queue;
  28     uint32_t interval;
  29     QEMUTimer release_timer;
  30 } FilterBufferState;
  31
  32 static void filter_buffer_flush(NetFilterState *nf)
  33 {
  34     FilterBufferState *s = FILTER_BUFFER(nf);
  35
  36     if (!qemu_net_queue_flush(s->incoming_queue)) {
  37         /* Unable to empty the queue, purge remaining packets */
  38         qemu_net_queue_purge(s->incoming_queue, nf->netdev);
  39     }
  40 }
  41
  42 static void filter_buffer_release_timer(void *opaque)
  43 {
  44     NetFilterState *nf = opaque;
  45     FilterBufferState *s = FILTER_BUFFER(nf);
  46
  47     /*
  48      * Note: filter_buffer_flush() drops packets that can't be sent
  49      * TODO: We should leave them queued.  But currently there's no way
  50      * for the next filter or receiver to notify us that it can receive
  51      * more packets.
  52      */
  53     filter_buffer_flush(nf);
  54     /* Timer rearmed to fire again in s->interval microseconds. */
  55     timer_mod(&s->release_timer,
  56               qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
  57 }
  58
  59 /* filter APIs */
  60 static ssize_t filter_buffer_receive_iov(NetFilterState *nf,
  61                                          NetClientState *sender,
  62                                          unsigned flags,
  63                                          const struct iovec *iov,
  64                                          int iovcnt,
  65                                          NetPacketSent *sent_cb)
  66 {
  67     FilterBufferState *s = FILTER_BUFFER(nf);
  68
  69     /*
  70      * We return size when buffer a packet, the sender will take it as
  71      * a already sent packet, so sent_cb should not be called later.
  72      *
  73      * FIXME: Even if the guest can't receive packets for some reasons,
  74      * the filter can still accept packets until its internal queue is full.
  75      * For example:
  76      *   For some reason, receiver could not receive more packets
  77      * (.can_receive() returns zero). Without a filter, at most one packet
  78      * will be queued in incoming queue and sender's poll will be disabled
  79      * unit its sent_cb() was called. With a filter, it will keep receiving
  80      * the packets without caring about the receiver. This is suboptimal.
  81      * May need more thoughts (e.g keeping sent_cb).
  82      */
  83     qemu_net_queue_append_iov(s->incoming_queue, sender, flags,
  84                               iov, iovcnt, NULL);
  85     return iov_size(iov, iovcnt);
  86 }
  87
  88 static void filter_buffer_cleanup(NetFilterState *nf)
  89 {
  90     FilterBufferState *s = FILTER_BUFFER(nf);
  91
  92     if (s->interval) {
  93         timer_del(&s->release_timer);
  94     }
  95
  96     /* flush packets */
  97     if (s->incoming_queue) {
  98         filter_buffer_flush(nf);
  99         g_free(s->incoming_queue);
 100     }
 101 }
 102
 103 static void filter_buffer_setup_timer(NetFilterState *nf)
 104 {
 105     FilterBufferState *s = FILTER_BUFFER(nf);
 106
 107     if (s->interval) {
 108         timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
 109                       filter_buffer_release_timer, nf);
 110         /* Timer armed to fire in s->interval microseconds. */
 111         timer_mod(&s->release_timer,
 112                   qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
 113     }
 114 }
 115
 116 static void filter_buffer_setup(NetFilterState *nf, Error **errp)
 117 {
 118     FilterBufferState *s = FILTER_BUFFER(nf);
 119
 120     /*
 121      * We may want to accept zero interval when VM FT solutions like MC
 122      * or COLO use this filter to release packets on demand.
 123      */
 124     if (!s->interval) {
 125         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
 126                    "a non-zero interval");
 127         return;
 128     }
 129
 130     s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
 131     filter_buffer_setup_timer(nf);
 132 }
 133
 134 static void filter_buffer_status_changed(NetFilterState *nf, Error **errp)
 135 {
 136     FilterBufferState *s = FILTER_BUFFER(nf);
 137
 138     if (!nf->on) {
 139         if (s->interval) {
 140             timer_del(&s->release_timer);
 141         }
 142         filter_buffer_flush(nf);
 143     } else {
 144         filter_buffer_setup_timer(nf);
 145     }
 146 }
 147
 148 static void filter_buffer_class_init(ObjectClass *oc, void *data)
 149 {
 150     NetFilterClass *nfc = NETFILTER_CLASS(oc);
 151
 152     nfc->setup = filter_buffer_setup;
 153     nfc->cleanup = filter_buffer_cleanup;
 154     nfc->receive_iov = filter_buffer_receive_iov;
 155     nfc->status_changed = filter_buffer_status_changed;
 156 }
 157
 158 static void filter_buffer_get_interval(Object *obj, Visitor *v,
 159                                        const char *name, void *opaque,
 160                                        Error **errp)
 161 {
 162     FilterBufferState *s = FILTER_BUFFER(obj);
 163     uint32_t value = s->interval;
 164
 165     visit_type_uint32(v, name, &value, errp);
 166 }
 167
 168 static void filter_buffer_set_interval(Object *obj, Visitor *v,
 169                                        const char *name, void *opaque,
 170                                        Error **errp)
 171 {
 172     FilterBufferState *s = FILTER_BUFFER(obj);
 173     Error *local_err = NULL;
 174     uint32_t value;
 175
 176     visit_type_uint32(v, name, &value, &local_err);
 177     if (local_err) {
 178         goto out;
 179     }
 180     if (!value) {
 181         error_setg(&local_err, "Property '%s.%s' requires a positive value",
 182                    object_get_typename(obj), name);
 183         goto out;
 184     }
 185     s->interval = value;
 186
 187 out:
 188     error_propagate(errp, local_err);
 189 }
 190
 191 static void filter_buffer_init(Object *obj)
 192 {
 193     object_property_add(obj, "interval", "uint32",
 194                         filter_buffer_get_interval,
 195                         filter_buffer_set_interval, NULL, NULL, NULL);
 196 }
 197
 198 static const TypeInfo filter_buffer_info = {
 199     .name = TYPE_FILTER_BUFFER,
 200     .parent = TYPE_NETFILTER,
 201     .class_init = filter_buffer_class_init,
 202     .instance_init = filter_buffer_init,
 203     .instance_size = sizeof(FilterBufferState),
 204 };
 205
 206 static void register_types(void)
 207 {
 208     type_register_static(&filter_buffer_info);
 209 }
 210
 211 type_init(register_types);