[Qemu-devel] [PATCH V4 1/2] net/filter-mirror: implement filter-redirector

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

Filter-redirector is a netfilter plugin.
It gives qemu the ability to redirect net packet.
redirector can redirect filter's net packet to outdev.
and redirect indev's packet to filter.

                      filter
                        +
                        |
                        |
            redirector  |
               +--------------+
               |        |     |
               |        |     |
               |        |     |
  indev +-----------+   +---------->  outdev
               |    |         |
               |    |         |
               |    |         |
               +--------------+
                    |
                    |
                    v
                  filter

usage:

-netdev user,id=hn0
-chardev socket,id=s0,host=ip_primary,port=X,server,nowait
-chardev socket,id=s1,host=ip_primary,port=Y,server,nowait
-filter-redirector,id=r0,netdev=hn0,queue=tx/rx/all,indev=s0,outdev=s1

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
---
 net/filter-mirror.c | 236 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu-options.hx     |   9 ++
 vl.c                |   3 +-
 3 files changed, 247 insertions(+), 1 deletion(-)

diff --git a/net/filter-mirror.c b/net/filter-mirror.c
index 1b1ec16..77ece41 100644
--- a/net/filter-mirror.c
+++ b/net/filter-mirror.c
@@ -26,12 +26,23 @@
 #define FILTER_MIRROR(obj) \
     OBJECT_CHECK(MirrorState, (obj), TYPE_FILTER_MIRROR)
 
+#define FILTER_REDIRECTOR(obj) \
+    OBJECT_CHECK(MirrorState, (obj), TYPE_FILTER_REDIRECTOR)
+
 #define TYPE_FILTER_MIRROR "filter-mirror"
+#define TYPE_FILTER_REDIRECTOR "filter-redirector"
+#define REDIRECTOR_MAX_LEN NET_BUFSIZE
 
 typedef struct MirrorState {
     NetFilterState parent_obj;
+    char *indev;
     char *outdev;
+    CharDriverState *chr_in;
     CharDriverState *chr_out;
+    int state; /* 0 = getting length, 1 = getting data */
+    unsigned int index;
+    unsigned int packet_len;
+    uint8_t buf[REDIRECTOR_MAX_LEN];
 } MirrorState;
 
 static int filter_mirror_send(CharDriverState *chr_out,
@@ -68,6 +79,89 @@ err:
     return ret < 0 ? ret : -EIO;
 }
 
+static void
+redirector_to_filter(NetFilterState *nf, const uint8_t *buf, int len)
+{
+    struct iovec iov = {
+        .iov_base = (void *)buf,
+        .iov_len = len,
+    };
+
+    if (nf->direction == NET_FILTER_DIRECTION_ALL ||
+        nf->direction == NET_FILTER_DIRECTION_TX) {
+        qemu_netfilter_pass_to_next(nf->netdev, 0, &iov, 1, nf);
+    }
+
+    if (nf->direction == NET_FILTER_DIRECTION_ALL ||
+        nf->direction == NET_FILTER_DIRECTION_RX) {
+        qemu_netfilter_pass_to_next(nf->netdev->peer, 0, &iov, 1, nf);
+     }
+}
+
+static int redirector_chr_can_read(void *opaque)
+{
+    return REDIRECTOR_MAX_LEN;
+}
+
+static void redirector_chr_read(void *opaque, const uint8_t *buf, int size)
+{
+    NetFilterState *nf = opaque;
+    MirrorState *s = FILTER_REDIRECTOR(nf);
+    unsigned int l;
+
+    if (size == 0) {
+        /* the peer is closed ? */
+        return ;
+    }
+
+    /* most of code is stolen from net_socket_send */
+    while (size > 0) {
+        /* reassemble a packet from the network */
+        switch (s->state) {
+        case 0:
+            l = 4 - s->index;
+            if (l > size) {
+                l = size;
+            }
+            memcpy(s->buf + s->index, buf, l);
+            buf += l;
+            size -= l;
+            s->index += l;
+            if (s->index == 4) {
+                /* got length */
+                s->packet_len = ntohl(*(uint32_t *)s->buf);
+                s->index = 0;
+                s->state = 1;
+            }
+            break;
+        case 1:
+            l = s->packet_len - s->index;
+            if (l > size) {
+                l = size;
+            }
+            if (s->index + l <= sizeof(s->buf)) {
+                memcpy(s->buf + s->index, buf, l);
+            } else {
+                fprintf(stderr, "serious error: oversized packet received,"
+                    "connection terminated.\n");
+                s->state = 0;
+                /* FIXME: do something ? */
+                return;
+            }
+
+            s->index += l;
+            buf += l;
+            size -= l;
+            if (s->index >= s->packet_len) {
+                s->index = 0;
+                s->state = 0;
+                redirector_to_filter(nf, s->buf, s->packet_len);
+            }
+            break;
+        }
+    }
+}
+
 static ssize_t filter_mirror_receive_iov(NetFilterState *nf,
                                          NetClientState *sender,
                                          unsigned flags,
@@ -90,6 +184,27 @@ static ssize_t filter_mirror_receive_iov(NetFilterState *nf,
     return 0;
 }
 
+static ssize_t filter_redirector_receive_iov(NetFilterState *nf,
+                                         NetClientState *sender,
+                                         unsigned flags,
+                                         const struct iovec *iov,
+                                         int iovcnt,
+                                         NetPacketSent *sent_cb)
+{
+    MirrorState *s = FILTER_REDIRECTOR(nf);
+    int ret;
+
+    if (s->chr_out) {
+        ret = filter_mirror_send(s->chr_out, iov, iovcnt);
+        if (ret) {
+            error_report("filter_mirror_send failed(%s)", strerror(-ret));
+        }
+        return iov_size(iov, iovcnt);
+    } else {
+        return 0;
+    }
+}
+
 static void filter_mirror_cleanup(NetFilterState *nf)
 {
     MirrorState *s = FILTER_MIRROR(nf);
@@ -99,6 +214,18 @@ static void filter_mirror_cleanup(NetFilterState *nf)
     }
 }
 
+static void filter_redirector_cleanup(NetFilterState *nf)
+{
+    MirrorState *s = FILTER_REDIRECTOR(nf);
+
+    if (s->chr_in) {
+        qemu_chr_fe_release(s->chr_in);
+    }
+    if (s->chr_out) {
+        qemu_chr_fe_release(s->chr_out);
+    }
+}
+
 static void filter_mirror_setup(NetFilterState *nf, Error **errp)
 {
     MirrorState *s = FILTER_MIRROR(nf);
@@ -122,6 +249,48 @@ static void filter_mirror_setup(NetFilterState *nf, Error **errp)
     }
 }
 
+static void filter_redirector_setup(NetFilterState *nf, Error **errp)
+{
+    MirrorState *s = FILTER_REDIRECTOR(nf);
+
+    if (!s->indev && !s->outdev) {
+        error_setg(errp, "filter redirector needs 'indev' or "
+                "'outdev' at least one property set");
+        return;
+    } else if (s->indev && s->outdev) {
+        if (!strcmp(s->indev, s->outdev)) {
+            error_setg(errp, "filter redirector needs 'indev' and "
+                    "'outdev'  are not same");
+            return;
+        }
+    }
+
+    s->state = s->index = 0;
+
+    if (s->indev) {
+        s->chr_in = qemu_chr_find(s->indev);
+        if (s->chr_in == NULL) {
+            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                      "IN Device '%s' not found", s->indev);
+            return;
+        }
+
+        qemu_chr_fe_claim_no_fail(s->chr_in);
+        qemu_chr_add_handlers(s->chr_in, redirector_chr_can_read,
+                                redirector_chr_read, NULL, nf);
+    }
+
+    if (s->outdev) {
+        s->chr_out = qemu_chr_find(s->outdev);
+        if (s->chr_out == NULL) {
+            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                      "OUT Device '%s' not found", s->outdev);
+            return;
+        }
+        qemu_chr_fe_claim_no_fail(s->chr_out);
+    }
+}
+
 static void filter_mirror_class_init(ObjectClass *oc, void *data)
 {
     NetFilterClass *nfc = NETFILTER_CLASS(oc);
@@ -131,6 +300,31 @@ static void filter_mirror_class_init(ObjectClass *oc, void *data)
     nfc->receive_iov = filter_mirror_receive_iov;
 }
 
+static void filter_redirector_class_init(ObjectClass *oc, void *data)
+{
+    NetFilterClass *nfc = NETFILTER_CLASS(oc);
+
+    nfc->setup = filter_redirector_setup;
+    nfc->cleanup = filter_redirector_cleanup;
+    nfc->receive_iov = filter_redirector_receive_iov;
+}
+
+static char *filter_redirector_get_indev(Object *obj, Error **errp)
+{
+    MirrorState *s = FILTER_REDIRECTOR(obj);
+
+    return g_strdup(s->indev);
+}
+
+static void
+filter_redirector_set_indev(Object *obj, const char *value, Error **errp)
+{
+    MirrorState *s = FILTER_REDIRECTOR(obj);
+
+    g_free(s->indev);
+    s->indev = g_strdup(value);
+}
+
 static char *filter_mirror_get_outdev(Object *obj, Error **errp)
 {
     MirrorState *s = FILTER_MIRROR(obj);
@@ -152,12 +346,36 @@ filter_mirror_set_outdev(Object *obj, const char *value, Error **errp)
     }
 }
 
+static char *filter_redirector_get_outdev(Object *obj, Error **errp)
+{
+    MirrorState *s = FILTER_REDIRECTOR(obj);
+
+    return g_strdup(s->outdev);
+}
+
+static void
+filter_redirector_set_outdev(Object *obj, const char *value, Error **errp)
+{
+    MirrorState *s = FILTER_REDIRECTOR(obj);
+
+    g_free(s->outdev);
+    s->outdev = g_strdup(value);
+}
+
 static void filter_mirror_init(Object *obj)
 {
     object_property_add_str(obj, "outdev", filter_mirror_get_outdev,
                             filter_mirror_set_outdev, NULL);
 }
 
+static void filter_redirector_init(Object *obj)
+{
+    object_property_add_str(obj, "indev", filter_redirector_get_indev,
+                            filter_redirector_set_indev, NULL);
+    object_property_add_str(obj, "outdev", filter_redirector_get_outdev,
+                            filter_redirector_set_outdev, NULL);
+}
+
 static void filter_mirror_fini(Object *obj)
 {
     MirrorState *s = FILTER_MIRROR(obj);
@@ -165,6 +383,23 @@ static void filter_mirror_fini(Object *obj)
     g_free(s->outdev);
 }
 
+static void filter_redirector_fini(Object *obj)
+{
+    MirrorState *s = FILTER_REDIRECTOR(obj);
+
+    g_free(s->indev);
+    g_free(s->outdev);
+}
+
+static const TypeInfo filter_redirector_info = {
+    .name = TYPE_FILTER_REDIRECTOR,
+    .parent = TYPE_NETFILTER,
+    .class_init = filter_redirector_class_init,
+    .instance_init = filter_redirector_init,
+    .instance_finalize = filter_redirector_fini,
+    .instance_size = sizeof(MirrorState),
+};
+
 static const TypeInfo filter_mirror_info = {
     .name = TYPE_FILTER_MIRROR,
     .parent = TYPE_NETFILTER,
@@ -177,6 +412,7 @@ static const TypeInfo filter_mirror_info = {
 static void register_types(void)
 {
     type_register_static(&filter_mirror_info);
+    type_register_static(&filter_redirector_info);
 }
 
 type_init(register_types);
diff --git a/qemu-options.hx b/qemu-options.hx
index 5379cb5..796d053 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3821,6 +3821,15 @@ queue @var{all|rx|tx} is an option that can be applied to any netfilter.
 filter-mirror on netdev @var{netdevid},mirror net packet to chardev
 @var{chardevid}
 
+@item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},
+outdev=@var{chardevid}[,queue=@var{all|rx|tx}]
+
+filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
+@var{chardevid},and redirect indev's packet to filter.
+Create a filter-redirector we need to differ outdev id from indev id, id can not
+be the same. we can just use indev or outdev, but at least one of indev or outdev
+need to be specified.
+
 @item -object filter-dump,id=@var{id},netdev=@var{dev},file=@var{filename}][,maxlen=@var{len}]
 
 Dump the network traffic on netdev @var{dev} to the file specified by
diff --git a/vl.c b/vl.c
index 79bb11a..dc6e63a 100644
--- a/vl.c
+++ b/vl.c
@@ -2841,7 +2841,8 @@ static bool object_create_initial(const char *type)
      */
     if (g_str_equal(type, "filter-buffer") ||
         g_str_equal(type, "filter-dump") ||
-        g_str_equal(type, "filter-mirror")) {
+        g_str_equal(type, "filter-mirror") ||
+        g_str_equal(type, "filter-redirector")) {
         return false;
     }
 
-- 
1.9.1