summaryrefslogtreecommitdiffstats
path: root/net/filter-buffer.c
blob: f7265c50a8e127647f34805bb9b97f63570dfdd8 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/*
 * Copyright (c) 2015 FUJITSU LIMITED
 * Author: Yang Hongyang <yanghy@cn.fujitsu.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or
 * later.  See the COPYING file in the top-level directory.
 */

#include "qemu/osdep.h"
#include "net/filter.h"
#include "net/queue.h"
#include "qapi/error.h"
#include "qemu-common.h"
#include "qemu/timer.h"
#include "qemu/iov.h"
#include "qapi/qapi-builtin-visit.h"
#include "qapi/qmp/qerror.h"
#include "qom/object.h"

#define TYPE_FILTER_BUFFER "filter-buffer"

#define FILTER_BUFFER(obj) \
    OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)

typedef struct FilterBufferState {
    NetFilterState parent_obj;

    NetQueue *incoming_queue;
    uint32_t interval;
    QEMUTimer release_timer;
} FilterBufferState;

static void filter_buffer_flush(NetFilterState *nf)
{
    FilterBufferState *s = FILTER_BUFFER(nf);

    if (!qemu_net_queue_flush(s->incoming_queue)) {
        /* Unable to empty the queue, purge remaining packets */
        qemu_net_queue_purge(s->incoming_queue, nf->netdev);
    }
}

static void filter_buffer_release_timer(void *opaque)
{
    NetFilterState *nf = opaque;
    FilterBufferState *s = FILTER_BUFFER(nf);

    /*
     * Note: filter_buffer_flush() drops packets that can't be sent
     * TODO: We should leave them queued.  But currently there's no way
     * for the next filter or receiver to notify us that it can receive
     * more packets.
     */
    filter_buffer_flush(nf);
    /* Timer rearmed to fire again in s->interval microseconds. */
    timer_mod(&s->release_timer,
              qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
}

/* filter APIs */
static ssize_t filter_buffer_receive_iov(NetFilterState *nf,
                                         NetClientState *sender,
                                         unsigned flags,
                                         const struct iovec *iov,
                                         int iovcnt,
                                         NetPacketSent *sent_cb)
{
    FilterBufferState *s = FILTER_BUFFER(nf);

    /*
     * We return size when buffer a packet, the sender will take it as
     * a already sent packet, so sent_cb should not be called later.
     *
     * FIXME: Even if the guest can't receive packets for some reasons,
     * the filter can still accept packets until its internal queue is full.
     * For example:
     *   For some reason, receiver could not receive more packets
     * (.can_receive() returns zero). Without a filter, at most one packet
     * will be queued in incoming queue and sender's poll will be disabled
     * unit its sent_cb() was called. With a filter, it will keep receiving
     * the packets without caring about the receiver. This is suboptimal.
     * May need more thoughts (e.g keeping sent_cb).
     */
    qemu_net_queue_append_iov(s->incoming_queue, sender, flags,
                              iov, iovcnt, NULL);
    return iov_size(iov, iovcnt);
}

static void filter_buffer_cleanup(NetFilterState *nf)
{
    FilterBufferState *s = FILTER_BUFFER(nf);

    if (s->interval) {
        timer_del(&s->release_timer);
    }

    /* flush packets */
    if (s->incoming_queue) {
        filter_buffer_flush(nf);
        g_free(s->incoming_queue);
    }
}

static void filter_buffer_setup_timer(NetFilterState *nf)
{
    FilterBufferState *s = FILTER_BUFFER(nf);

    if (s->interval) {
        timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
                      filter_buffer_release_timer, nf);
        /* Timer armed to fire in s->interval microseconds. */
        timer_mod(&s->release_timer,
                  qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
    }
}

static void filter_buffer_setup(NetFilterState *nf, Error **errp)
{
    FilterBufferState *s = FILTER_BUFFER(nf);

    /*
     * We may want to accept zero interval when VM FT solutions like MC
     * or COLO use this filter to release packets on demand.
     */
    if (!s->interval) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
                   "a non-zero interval");
        return;
    }

    s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
    filter_buffer_setup_timer(nf);
}

static void filter_buffer_status_changed(NetFilterState *nf, Error **errp)
{
    FilterBufferState *s = FILTER_BUFFER(nf);

    if (!nf->on) {
        if (s->interval) {
            timer_del(&s->release_timer);
        }
        filter_buffer_flush(nf);
    } else {
        filter_buffer_setup_timer(nf);
    }
}

static void filter_buffer_class_init(ObjectClass *oc, void *data)
{
    NetFilterClass *nfc = NETFILTER_CLASS(oc);

    nfc->setup = filter_buffer_setup;
    nfc->cleanup = filter_buffer_cleanup;
    nfc->receive_iov = filter_buffer_receive_iov;
    nfc->status_changed = filter_buffer_status_changed;
}

static void filter_buffer_get_interval(Object *obj, Visitor *v,
                                       const char *name, void *opaque,
                                       Error **errp)
{
    FilterBufferState *s = FILTER_BUFFER(obj);
    uint32_t value = s->interval;

    visit_type_uint32(v, name, &value, errp);
}

static void filter_buffer_set_interval(Object *obj, Visitor *v,
                                       const char *name, void *opaque,
                                       Error **errp)
{
    FilterBufferState *s = FILTER_BUFFER(obj);
    Error *local_err = NULL;
    uint32_t value;

    visit_type_uint32(v, name, &value, &local_err);
    if (local_err) {
        goto out;
    }
    if (!value) {
        error_setg(&local_err, "Property '%s.%s' requires a positive value",
                   object_get_typename(obj), name);
        goto out;
    }
    s->interval = value;

out:
    error_propagate(errp, local_err);
}

static void filter_buffer_init(Object *obj)
{
    object_property_add(obj, "interval", "uint32",
                        filter_buffer_get_interval,
                        filter_buffer_set_interval, NULL, NULL, NULL);
}

static const TypeInfo filter_buffer_info = {
    .name = TYPE_FILTER_BUFFER,
    .parent = TYPE_NETFILTER,
    .class_init = filter_buffer_class_init,
    .instance_init = filter_buffer_init,
    .instance_size = sizeof(FilterBufferState),
};

static void register_types(void)
{
    type_register_static(&filter_buffer_info);
}

type_init(register_types);