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 "qemu-common.h"
  13 #include "qemu/timer.h"
  14 #include "qemu/iov.h"
  15 #include "qapi/qmp/qerror.h"
  16 #include "qapi-visit.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(NetFilterState *nf, Error **errp)
 104 {
 105     FilterBufferState *s = FILTER_BUFFER(nf);
 106
 107     /*
 108      * We may want to accept zero interval when VM FT solutions like MC
 109      * or COLO use this filter to release packets on demand.
 110      */
 111     if (!s->interval) {
 112         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
 113                    "a non-zero interval");
 114         return;
 115     }
 116
 117     s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
 118     if (s->interval) {
 119         timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
 120                       filter_buffer_release_timer, nf);
 121         /* Timer armed to fire in s->interval microseconds. */
 122         timer_mod(&s->release_timer,
 123                   qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
 124     }
 125 }
 126
 127 static void filter_buffer_class_init(ObjectClass *oc, void *data)
 128 {
 129     NetFilterClass *nfc = NETFILTER_CLASS(oc);
 130
 131     nfc->setup = filter_buffer_setup;
 132     nfc->cleanup = filter_buffer_cleanup;
 133     nfc->receive_iov = filter_buffer_receive_iov;
 134 }
 135
 136 static void filter_buffer_get_interval(Object *obj, Visitor *v,
 137                                        const char *name, void *opaque,
 138                                        Error **errp)
 139 {
 140     FilterBufferState *s = FILTER_BUFFER(obj);
 141     uint32_t value = s->interval;
 142
 143     visit_type_uint32(v, name, &value, errp);
 144 }
 145
 146 static void filter_buffer_set_interval(Object *obj, Visitor *v,
 147                                        const char *name, void *opaque,
 148                                        Error **errp)
 149 {
 150     FilterBufferState *s = FILTER_BUFFER(obj);
 151     Error *local_err = NULL;
 152     uint32_t value;
 153
 154     visit_type_uint32(v, name, &value, &local_err);
 155     if (local_err) {
 156         goto out;
 157     }
 158     if (!value) {
 159         error_setg(&local_err, "Property '%s.%s' requires a positive value",
 160                    object_get_typename(obj), name);
 161         goto out;
 162     }
 163     s->interval = value;
 164
 165 out:
 166     error_propagate(errp, local_err);
 167 }
 168
 169 static void filter_buffer_init(Object *obj)
 170 {
 171     object_property_add(obj, "interval", "int",
 172                         filter_buffer_get_interval,
 173                         filter_buffer_set_interval, NULL, NULL, NULL);
 174 }
 175
 176 static const TypeInfo filter_buffer_info = {
 177     .name = TYPE_FILTER_BUFFER,
 178     .parent = TYPE_NETFILTER,
 179     .class_init = filter_buffer_class_init,
 180     .instance_init = filter_buffer_init,
 181     .instance_size = sizeof(FilterBufferState),
 182 };
 183
 184 static void register_types(void)
 185 {
 186     type_register_static(&filter_buffer_info);
 187 }
 188
 189 type_init(register_types);