Rename usbredir channel code to spicevmc

While discussing various things with Alon in Vancouver, it came up that
having a channel which simply passes through data coming out of a qemu
chardev frontend unmodified, like the usbredir channel does, can be used
for a lot of other cases too. To facilitate this the usbredir channel code
will be turned into a generic spicevmc channel, which is just a passthrough
to the client, from the spicevmc chardev.

This patch renames usbredir.c to spicevmc.c and changes the prefix of all
functions / structs to match. This should make clear that the code is not
usbredir specific.

Some examples of why having a generic spicevmc pass through is good:
1) We could add a monitor channel, allowing access to the qemu monitor from
the spice client, since the monitor is a chardev frontend we could re-use
the generic spicevmc channel server code, so all that is needed to add this
(server side) would be reserving a new channel id for this.

2) We could allow users to come up with new channels of their own, without
requiring qemu or server modification. The idea is to allow doing something
like this on the qemu startup cmdline:
-chardev spicevmc,name=generic,channelid=128

To ensure these new "generic" channels cannot conflict with newly added
official types, they must start at the SPICE_CHANNEL_USER_DEFINED_START value
(128).

These new user defined channels could then either be used with a special
modified client, with client plugins (if we add support for those), or
by exporting them on the client side for use by an external ap, see below.

3) We could also add support to the client to make user-defined channels
end in a unix socket / pipe, allowing handling of the data by an external app,
we could for example have a new spice client cmdline argument like this:
--custom-channel unixsocket=/tmp/mysocket,channelid=128

This would allow for something like:
$random app on guest -> virtio-serial -> spicevmc chardev ->
 -> spicevmc channel -> unix socket -> $random app on client

4) On hind sight this could also have been used for the smartcard stuff,
with a 1 channel / reader model, rather then the current multiplexing code
where we've our own multiplexing protocol wrapper over the libcacard
smartcard protocol.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 275 insertions, 0 deletions

diff --git a/server/spicevmc.c b/server/spicevmc.c
new file mode 100644
index 00000000..9ccc0d17
--- /dev/null
+++ b/server/spicevmc.c
@@ -0,0 +1,275 @@
+/* spice-server spicevmc passthrough channel code
+
+   Copyright (C) 2011 Red Hat, Inc.
+
+   Red Hat Authors:
+   Hans de Goede <hdegoede@redhat.com>
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <assert.h>
+
+#include "server/char_device.h"
+#include "server/red_channel.h"
+#include "server/reds.h"
+
+/* 64K should be enough for all but the largest writes + 32 bytes hdr */
+#define BUF_SIZE (64 * 1024 + 32)
+
+typedef struct SpiceVmcPipeItem {
+    PipeItem base;
+    /* writes which don't fit this will get split, this is not a problem */
+    uint8_t buf[BUF_SIZE];
+    uint32_t buf_used;
+} SpiceVmcPipeItem;
+
+typedef struct SpiceVmcState {
+    RedChannel channel; /* Must be the first item */
+    RedChannelClient *rcc;
+    SpiceCharDeviceState chardev_st;
+    SpiceCharDeviceInstance *chardev_sin;
+    SpiceVmcPipeItem *pipe_item;
+    uint8_t *rcv_buf;
+    uint32_t rcv_buf_size;
+    int rcv_buf_in_use;
+} SpiceVmcState;
+
+static void spicevmc_chardev_wakeup(SpiceCharDeviceInstance *sin)
+{
+    SpiceVmcState *state;
+    SpiceCharDeviceInterface *sif;
+    int n;
+
+    state = SPICE_CONTAINEROF(sin->st, SpiceVmcState, chardev_st);
+    sif = SPICE_CONTAINEROF(sin->base.sif, SpiceCharDeviceInterface, base);
+
+    if (!state->rcc) {
+        return;
+    }
+
+    do {
+        if (!state->pipe_item) {
+            state->pipe_item = spice_malloc(sizeof(SpiceVmcPipeItem));
+            red_channel_pipe_item_init(&state->channel,
+                                       &state->pipe_item->base, 0);
+        }
+
+        n = sif->read(sin, state->pipe_item->buf,
+                      sizeof(state->pipe_item->buf));
+        if (n > 0) {
+            state->pipe_item->buf_used = n;
+            red_channel_client_pipe_add_push(state->rcc,
+                                             &state->pipe_item->base);
+            state->pipe_item = NULL;
+        }
+    } while (n > 0);
+}
+
+static int spicevmc_red_channel_client_config_socket(RedChannelClient *rcc)
+{
+    return TRUE;
+}
+
+static void spicevmc_red_channel_client_on_disconnect(RedChannelClient *rcc)
+{
+    SpiceVmcState *state;
+    SpiceCharDeviceInstance *sin;
+    SpiceCharDeviceInterface *sif;
+
+    if (!rcc) {
+        return;
+    }
+
+    state = SPICE_CONTAINEROF(rcc->channel, SpiceVmcState, channel);
+    sin = state->chardev_sin;
+    sif = SPICE_CONTAINEROF(sin->base.sif, SpiceCharDeviceInterface, base);
+
+    red_channel_client_destroy(rcc);
+    state->rcc = NULL;
+    if (sif->state) {
+        sif->state(sin, 0);
+    }
+}
+
+static int spicevmc_red_channel_client_handle_message(RedChannelClient *rcc,
+    SpiceDataHeader *header, uint8_t *msg)
+{
+    SpiceVmcState *state;
+    SpiceCharDeviceInstance *sin;
+    SpiceCharDeviceInterface *sif;
+
+    state = SPICE_CONTAINEROF(rcc->channel, SpiceVmcState, channel);
+    sin = state->chardev_sin;
+    sif = SPICE_CONTAINEROF(sin->base.sif, SpiceCharDeviceInterface, base);
+
+    if (header->type != SPICE_MSGC_SPICEVMC_DATA) {
+        return red_channel_client_handle_message(rcc, header->size,
+                                                 header->type, msg);
+    }
+
+    /*
+     * qemu spicevmc will consume everything we give it, no need for
+     * flow control checks (or to use a pipe).
+     */
+    sif->write(sin, msg, header->size);
+
+    return TRUE;
+}
+
+static uint8_t *spicevmc_red_channel_alloc_msg_rcv_buf(RedChannelClient *rcc,
+    SpiceDataHeader *msg_header)
+{
+    SpiceVmcState *state;
+
+    state = SPICE_CONTAINEROF(rcc->channel, SpiceVmcState, channel);
+
+    assert(!state->rcv_buf_in_use);
+
+    if (msg_header->size > state->rcv_buf_size) {
+        state->rcv_buf = spice_realloc(state->rcv_buf, msg_header->size);
+        state->rcv_buf_size = msg_header->size;
+    }
+
+    state->rcv_buf_in_use = 1;
+
+    return state->rcv_buf;
+}
+
+static void spicevmc_red_channel_release_msg_rcv_buf(RedChannelClient *rcc,
+    SpiceDataHeader *msg_header, uint8_t *msg)
+{
+    SpiceVmcState *state;
+
+    state = SPICE_CONTAINEROF(rcc->channel, SpiceVmcState, channel);
+
+    /* NOOP, we re-use the buffer every time and only free it on destruction */
+    state->rcv_buf_in_use = 0;
+}
+
+static void spicevmc_red_channel_hold_pipe_item(RedChannelClient *rcc,
+    PipeItem *item)
+{
+    /* NOOP */
+}
+
+static void spicevmc_red_channel_send_item(RedChannelClient *rcc,
+    PipeItem *item)
+{
+    SpiceVmcPipeItem *i = SPICE_CONTAINEROF(item, SpiceVmcPipeItem, base);
+    SpiceMarshaller *m = red_channel_client_get_marshaller(rcc);
+
+    red_channel_client_init_send_data(rcc, SPICE_MSG_SPICEVMC_DATA, item);
+    spice_marshaller_add_ref(m, i->buf, i->buf_used);
+    red_channel_client_begin_send_message(rcc);
+}
+
+static void spicevmc_red_channel_release_pipe_item(RedChannelClient *rcc,
+    PipeItem *item, int item_pushed)
+{
+    free(item);
+}
+
+static void spicevmc_connect(RedChannel *channel, RedClient *client,
+    RedsStream *stream, int migration, int num_common_caps,
+    uint32_t *common_caps, int num_caps, uint32_t *caps)
+{
+    RedChannelClient *rcc;
+    SpiceVmcState *state;
+    SpiceCharDeviceInstance *sin;
+    SpiceCharDeviceInterface *sif;
+
+    state = SPICE_CONTAINEROF(channel, SpiceVmcState, channel);
+    sin = state->chardev_sin;
+    sif = SPICE_CONTAINEROF(sin->base.sif, SpiceCharDeviceInterface, base);
+
+    if (state->rcc) {
+        WARN("channel client %d:%d (%p) already connected, refusing second connection\n",
+             channel->type, channel->id, state->rcc);
+        // TODO: notify client in advance about the in use channel using
+        // SPICE_MSG_MAIN_CHANNEL_IN_USE (for example)
+        reds_stream_free(stream);
+        return;
+    }
+
+    rcc = red_channel_client_create(sizeof(RedChannelClient), channel, client, stream);
+    if (!rcc) {
+        return;
+    }
+    state->rcc = rcc;
+    red_channel_client_ack_zero_messages_window(rcc);
+
+    if (sif->state) {
+        sif->state(sin, 1);
+    }
+}
+
+static void spicevmc_migrate(RedChannelClient *rcc)
+{
+    /* NOOP */
+}
+
+void spicevmc_device_connect(SpiceCharDeviceInstance *sin,
+    uint8_t channel_type)
+{
+    static uint8_t id[256] = { 0, };
+    SpiceVmcState *state;
+    ChannelCbs channel_cbs = {0,};
+    ClientCbs client_cbs = {0,};
+
+    channel_cbs.config_socket = spicevmc_red_channel_client_config_socket;
+    channel_cbs.on_disconnect = spicevmc_red_channel_client_on_disconnect;
+    channel_cbs.send_item = spicevmc_red_channel_send_item;
+    channel_cbs.hold_item = spicevmc_red_channel_hold_pipe_item;
+    channel_cbs.release_item = spicevmc_red_channel_release_pipe_item;
+    channel_cbs.alloc_recv_buf = spicevmc_red_channel_alloc_msg_rcv_buf;
+    channel_cbs.release_recv_buf = spicevmc_red_channel_release_msg_rcv_buf;
+
+    state = (SpiceVmcState*)red_channel_create(sizeof(SpiceVmcState),
+                                   core, channel_type, id[channel_type]++,
+                                   FALSE /* migration - TODO? */,
+                                   FALSE /* handle_acks */,
+                                   spicevmc_red_channel_client_handle_message,
+                                   &channel_cbs);
+    red_channel_init_outgoing_messages_window(&state->channel);
+    state->chardev_st.wakeup = spicevmc_chardev_wakeup;
+    state->chardev_sin = sin;
+    state->rcv_buf = spice_malloc(BUF_SIZE);
+    state->rcv_buf_size = BUF_SIZE;
+
+    client_cbs.connect = spicevmc_connect;
+    client_cbs.migrate = spicevmc_migrate;
+    red_channel_register_client_cbs(&state->channel, &client_cbs);
+
+    sin->st = &state->chardev_st;
+
+    reds_register_channel(&state->channel);
+}
+
+/* Must be called from RedClient handling thread. */
+void spicevmc_device_disconnect(SpiceCharDeviceInstance *sin)
+{
+    SpiceVmcState *state;
+
+    state = SPICE_CONTAINEROF(sin->st, SpiceVmcState, chardev_st);
+
+    reds_unregister_channel(&state->channel);
+
+    free(state->pipe_item);
+    free(state->rcv_buf);
+    red_channel_destroy(&state->channel);
+}