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 OBJECT_DECLARE_SIMPLE_TYPE(FilterBufferState, FILTER_BUFFER)
  22
  23 struct FilterBufferState {
  24     NetFilterState parent_obj;
  25
  26     NetQueue *incoming_queue;
  27     uint32_t interval;
  28     QEMUTimer release_timer;
  29 };
  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 false). 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_timer(NetFilterState *nf)
 103 {
 104     FilterBufferState *s = FILTER_BUFFER(nf);
 105
 106     if (s->interval) {
 107         timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
 108                       filter_buffer_release_timer, nf);
 109         /* Timer armed to fire in s->interval microseconds. */
 110         timer_mod(&s->release_timer,
 111                   qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
 112     }
 113 }
 114
 115 static void filter_buffer_setup(NetFilterState *nf, Error **errp)
 116 {
 117     FilterBufferState *s = FILTER_BUFFER(nf);
 118
 119     /*
 120      * We may want to accept zero interval when VM FT solutions like MC
 121      * or COLO use this filter to release packets on demand.
 122      */
 123     if (!s->interval) {
 124         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
 125                    "a non-zero interval");
 126         return;
 127     }
 128
 129     s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
 130     filter_buffer_setup_timer(nf);
 131 }
 132
 133 static void filter_buffer_status_changed(NetFilterState *nf, Error **errp)
 134 {
 135     FilterBufferState *s = FILTER_BUFFER(nf);
 136
 137     if (!nf->on) {
 138         if (s->interval) {
 139             timer_del(&s->release_timer);
 140         }
 141         filter_buffer_flush(nf);
 142     } else {
 143         filter_buffer_setup_timer(nf);
 144     }
 145 }
 146
 147 static void filter_buffer_get_interval(Object *obj, Visitor *v,
 148                                        const char *name, void *opaque,
 149                                        Error **errp)
 150 {
 151     FilterBufferState *s = FILTER_BUFFER(obj);
 152     uint32_t value = s->interval;
 153
 154     visit_type_uint32(v, name, &value, errp);
 155 }
 156
 157 static void filter_buffer_set_interval(Object *obj, Visitor *v,
 158                                        const char *name, void *opaque,
 159                                        Error **errp)
 160 {
 161     FilterBufferState *s = FILTER_BUFFER(obj);
 162     uint32_t value;
 163
 164     if (!visit_type_uint32(v, name, &value, errp)) {
 165         return;
 166     }
 167     if (!value) {
 168         error_setg(errp, "Property '%s.%s' requires a positive value",
 169                    object_get_typename(obj), name);
 170         return;
 171     }
 172     s->interval = value;
 173 }
 174
 175 static void filter_buffer_class_init(ObjectClass *oc, void *data)
 176 {
 177     NetFilterClass *nfc = NETFILTER_CLASS(oc);
 178
 179     object_class_property_add(oc, "interval", "uint32",
 180                               filter_buffer_get_interval,
 181                               filter_buffer_set_interval, NULL, NULL);
 182
 183     nfc->setup = filter_buffer_setup;
 184     nfc->cleanup = filter_buffer_cleanup;
 185     nfc->receive_iov = filter_buffer_receive_iov;
 186     nfc->status_changed = filter_buffer_status_changed;
 187 }
 188
 189 static const TypeInfo filter_buffer_info = {
 190     .name = TYPE_FILTER_BUFFER,
 191     .parent = TYPE_NETFILTER,
 192     .class_init = filter_buffer_class_init,
 193     .instance_size = sizeof(FilterBufferState),
 194 };
 195
 196 static void register_types(void)
 197 {
 198     type_register_static(&filter_buffer_info);
 199 }
 200
 201 type_init(register_types);