Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 246 insertions, 0 deletions

diff --git a/chardev/char-udp.c b/chardev/char-udp.c
new file mode 100644
index 000000000..6756e6992
--- /dev/null
+++ b/chardev/char-udp.c
@@ -0,0 +1,246 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "chardev/char.h"
+#include "io/channel-socket.h"
+#include "qapi/error.h"
+#include "qemu/module.h"
+#include "qemu/option.h"
+
+#include "chardev/char-io.h"
+#include "qom/object.h"
+
+/***********************************************************/
+/* UDP Net console */
+
+struct UdpChardev {
+    Chardev parent;
+    QIOChannel *ioc;
+    uint8_t buf[CHR_READ_BUF_LEN];
+    int bufcnt;
+    int bufptr;
+    int max_size;
+};
+typedef struct UdpChardev UdpChardev;
+
+DECLARE_INSTANCE_CHECKER(UdpChardev, UDP_CHARDEV,
+                         TYPE_CHARDEV_UDP)
+
+/* Called with chr_write_lock held.  */
+static int udp_chr_write(Chardev *chr, const uint8_t *buf, int len)
+{
+    UdpChardev *s = UDP_CHARDEV(chr);
+
+    return qio_channel_write(
+        s->ioc, (const char *)buf, len, NULL);
+}
+
+static void udp_chr_flush_buffer(UdpChardev *s)
+{
+    Chardev *chr = CHARDEV(s);
+
+    while (s->max_size > 0 && s->bufptr < s->bufcnt) {
+        int n = MIN(s->max_size, s->bufcnt - s->bufptr);
+        qemu_chr_be_write(chr, &s->buf[s->bufptr], n);
+        s->bufptr += n;
+        s->max_size = qemu_chr_be_can_write(chr);
+    }
+}
+
+static int udp_chr_read_poll(void *opaque)
+{
+    Chardev *chr = CHARDEV(opaque);
+    UdpChardev *s = UDP_CHARDEV(opaque);
+
+    s->max_size = qemu_chr_be_can_write(chr);
+
+    /* If there were any stray characters in the queue process them
+     * first
+     */
+    udp_chr_flush_buffer(s);
+
+    return s->max_size;
+}
+
+static gboolean udp_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
+{
+    Chardev *chr = CHARDEV(opaque);
+    UdpChardev *s = UDP_CHARDEV(opaque);
+    ssize_t ret;
+
+    if (s->max_size == 0) {
+        return TRUE;
+    }
+    ret = qio_channel_read(
+        s->ioc, (char *)s->buf, sizeof(s->buf), NULL);
+    if (ret <= 0) {
+        remove_fd_in_watch(chr);
+        return FALSE;
+    }
+    s->bufcnt = ret;
+    s->bufptr = 0;
+    udp_chr_flush_buffer(s);
+
+    return TRUE;
+}
+
+static void udp_chr_update_read_handler(Chardev *chr)
+{
+    UdpChardev *s = UDP_CHARDEV(chr);
+
+    remove_fd_in_watch(chr);
+    if (s->ioc) {
+        chr->gsource = io_add_watch_poll(chr, s->ioc,
+                                           udp_chr_read_poll,
+                                           udp_chr_read, chr,
+                                           chr->gcontext);
+    }
+}
+
+static void char_udp_finalize(Object *obj)
+{
+    Chardev *chr = CHARDEV(obj);
+    UdpChardev *s = UDP_CHARDEV(obj);
+
+    remove_fd_in_watch(chr);
+    if (s->ioc) {
+        object_unref(OBJECT(s->ioc));
+    }
+    qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
+}
+
+static void qemu_chr_parse_udp(QemuOpts *opts, ChardevBackend *backend,
+                               Error **errp)
+{
+    const char *host = qemu_opt_get(opts, "host");
+    const char *port = qemu_opt_get(opts, "port");
+    const char *localaddr = qemu_opt_get(opts, "localaddr");
+    const char *localport = qemu_opt_get(opts, "localport");
+    bool has_local = false;
+    SocketAddressLegacy *addr;
+    ChardevUdp *udp;
+
+    backend->type = CHARDEV_BACKEND_KIND_UDP;
+    if (host == NULL || strlen(host) == 0) {
+        host = "localhost";
+    }
+    if (port == NULL || strlen(port) == 0) {
+        error_setg(errp, "chardev: udp: remote port not specified");
+        return;
+    }
+    if (localport == NULL || strlen(localport) == 0) {
+        localport = "0";
+    } else {
+        has_local = true;
+    }
+    if (localaddr == NULL || strlen(localaddr) == 0) {
+        localaddr = "";
+    } else {
+        has_local = true;
+    }
+
+    udp = backend->u.udp.data = g_new0(ChardevUdp, 1);
+    qemu_chr_parse_common(opts, qapi_ChardevUdp_base(udp));
+
+    addr = g_new0(SocketAddressLegacy, 1);
+    addr->type = SOCKET_ADDRESS_TYPE_INET;
+    addr->u.inet.data = g_new(InetSocketAddress, 1);
+    *addr->u.inet.data = (InetSocketAddress) {
+        .host = g_strdup(host),
+        .port = g_strdup(port),
+        .has_ipv4 = qemu_opt_get(opts, "ipv4"),
+        .ipv4 = qemu_opt_get_bool(opts, "ipv4", 0),
+        .has_ipv6 = qemu_opt_get(opts, "ipv6"),
+        .ipv6 = qemu_opt_get_bool(opts, "ipv6", 0),
+    };
+    udp->remote = addr;
+
+    if (has_local) {
+        udp->has_local = true;
+        addr = g_new0(SocketAddressLegacy, 1);
+        addr->type = SOCKET_ADDRESS_TYPE_INET;
+        addr->u.inet.data = g_new(InetSocketAddress, 1);
+        *addr->u.inet.data = (InetSocketAddress) {
+            .host = g_strdup(localaddr),
+            .port = g_strdup(localport),
+        };
+        udp->local = addr;
+    }
+}
+
+static void qmp_chardev_open_udp(Chardev *chr,
+                                 ChardevBackend *backend,
+                                 bool *be_opened,
+                                 Error **errp)
+{
+    ChardevUdp *udp = backend->u.udp.data;
+    SocketAddress *local_addr = socket_address_flatten(udp->local);
+    SocketAddress *remote_addr = socket_address_flatten(udp->remote);
+    QIOChannelSocket *sioc = qio_channel_socket_new();
+    char *name;
+    UdpChardev *s = UDP_CHARDEV(chr);
+    int ret;
+
+    ret = qio_channel_socket_dgram_sync(sioc, local_addr, remote_addr, errp);
+    qapi_free_SocketAddress(local_addr);
+    qapi_free_SocketAddress(remote_addr);
+    if (ret < 0) {
+        object_unref(OBJECT(sioc));
+        return;
+    }
+
+    name = g_strdup_printf("chardev-udp-%s", chr->label);
+    qio_channel_set_name(QIO_CHANNEL(sioc), name);
+    g_free(name);
+
+    s->ioc = QIO_CHANNEL(sioc);
+    /* be isn't opened until we get a connection */
+    *be_opened = false;
+}
+
+static void char_udp_class_init(ObjectClass *oc, void *data)
+{
+    ChardevClass *cc = CHARDEV_CLASS(oc);
+
+    cc->parse = qemu_chr_parse_udp;
+    cc->open = qmp_chardev_open_udp;
+    cc->chr_write = udp_chr_write;
+    cc->chr_update_read_handler = udp_chr_update_read_handler;
+}
+
+static const TypeInfo char_udp_type_info = {
+    .name = TYPE_CHARDEV_UDP,
+    .parent = TYPE_CHARDEV,
+    .instance_size = sizeof(UdpChardev),
+    .instance_finalize = char_udp_finalize,
+    .class_init = char_udp_class_init,
+};
+
+static void register_types(void)
+{
+    type_register_static(&char_udp_type_info);
+}
+
+type_init(register_types);