[FYI,13/46] io: add QIOChannelWebsock class

Add a QIOChannel subclass that can run the websocket protocol over
the top of another QIOChannel instance. This initial implementation
is only capable of acting as a websockets server. There is no support
for acting as a websockets client yet.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/channel-websock.h | 108 +++++
 io/Makefile.objs             |   1 +
 io/channel-websock.c         | 965 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1074 insertions(+)
 create mode 100644 include/io/channel-websock.h
 create mode 100644 io/channel-websock.c

* Daniel P. Berrange (berrange@redhat.com) wrote:
> Add a QIOChannel subclass that can run the websocket protocol over
> the top of another QIOChannel instance. This initial implementation
> is only capable of acting as a websockets server. There is no support
> for acting as a websockets client yet.
> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  include/io/channel-websock.h | 108 +++++
>  io/Makefile.objs             |   1 +
>  io/channel-websock.c         | 965 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1074 insertions(+)
>  create mode 100644 include/io/channel-websock.h
>  create mode 100644 io/channel-websock.c
> 
> diff --git a/include/io/channel-websock.h b/include/io/channel-websock.h
> new file mode 100644
> index 0000000..8e69d86
> --- /dev/null
> +++ b/include/io/channel-websock.h
> @@ -0,0 +1,108 @@
> +/*
> + * QEMU I/O channels driver websockets
> + *
> + * Copyright (c) 2015 Red Hat, Inc.
> + *
> + * 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 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/>.
> + *
> + */
> +
> +#ifndef QIO_CHANNEL_WEBSOCK_H__
> +#define QIO_CHANNEL_WEBSOCK_H__
> +
> +#include "io/channel.h"
> +#include "io/buffer.h"
> +#include "io/task.h"
> +
> +#define TYPE_QIO_CHANNEL_WEBSOCK "qio-channel-websock"
> +#define QIO_CHANNEL_WEBSOCK(obj)                                     \
> +    OBJECT_CHECK(QIOChannelWebsock, (obj), TYPE_QIO_CHANNEL_WEBSOCK)
> +
> +typedef struct QIOChannelWebsock QIOChannelWebsock;
> +typedef union QIOChannelWebsockMask QIOChannelWebsockMask;
> +
> +union QIOChannelWebsockMask {
> +    char c[4];
> +    uint32_t u;
> +};
> +
> +/**
> + * QIOChannelWebsock
> + *
> + * The QIOChannelWebsock class provides a channel wrapper which
> + * can transparently run the HTTP websockets protocol. This is
> + * usually used over a TCP socket, but there is actually no
> + * technical restriction on which type of master channel is
> + * used as the transport.
> + *
> + * This channel object is currently only capable of running as
> + * a websocket server and is a pretty crude implementation
> + * of it, not supporting the full websockets protocol feature
> + * set. It is sufficient to use with a simple websockets
> + * client for encapsulating VNC for noVNC in-browser client.
> + */
> +
> +struct QIOChannelWebsock {
> +    QIOChannel parent;
> +    QIOChannel *master;
> +    QIOBuffer encinput;
> +    QIOBuffer encoutput;
> +    QIOBuffer rawinput;
> +    QIOBuffer rawoutput;
> +    size_t payload_remain;
> +    QIOChannelWebsockMask mask;
> +    guint io_tag;
> +    Error *io_err;
> +    gboolean io_eof;
> +};
> +
> +/**
> + * qio_channel_websock_new_server:
> + * @master: the underlying channel object
> + *
> + * Create a new websockets channel that runs the server
> + * side of the protocol.
> + *
> + * After creating the channel, it is mandatory to call
> + * the qio_channel_websock_handshake() method before attempting
> + * todo any I/O on the channel.
> + *
> + * Once the handshake has completed, all I/O should be done
> + * via the new websocket channel object and not the original
> + * master channel
> + *
> + * Returns: the new websockets channel object
> + */
> +QIOChannelWebsock *
> +qio_channel_websock_new_server(QIOChannel *master);
> +
> +/**
> + * qio_channel_websock_handshake:
> + * @ioc: the websocket channel object
> + * @func: the callback to invoke when completed
> + * @opaque: opaque data to pass to @func
> + * @destroy: optional callback to free @opaque
> + *
> + * Perform the websocket handshake. This method
> + * will return immediately and the handshake will
> + * continue in the background, provided the main
> + * loop is running. When the handshake is complete,
> + * or fails, the @func callback will be invoked.
> + */
> +void qio_channel_websock_handshake(QIOChannelWebsock *ioc,
> +                                   QIOTaskFunc func,
> +                                   gpointer opaque,
> +                                   GDestroyNotify destroy);
> +
> +#endif /* QIO_CHANNEL_WEBSOCK_H__ */
> diff --git a/io/Makefile.objs b/io/Makefile.objs
> index 2b33d3c..9f93087 100644
> --- a/io/Makefile.objs
> +++ b/io/Makefile.objs
> @@ -5,3 +5,4 @@ io-obj-y += channel-watch.o
>  io-obj-y += channel-socket.o
>  io-obj-y += channel-file.o
>  io-obj-y += channel-tls.o
> +io-obj-y += channel-websock.o
> diff --git a/io/channel-websock.c b/io/channel-websock.c
> new file mode 100644
> index 0000000..0345b90
> --- /dev/null
> +++ b/io/channel-websock.c
> @@ -0,0 +1,965 @@
> +/*
> + * QEMU I/O channels driver websockets
> + *
> + * Copyright (c) 2015 Red Hat, Inc.
> + *
> + * 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 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/>.
> + *
> + */
> +
> +#include "io/channel-websock.h"
> +#include "crypto/hash.h"
> +
> +#include <glib/gi18n.h>
> +
> +/* #define DEBUG_IOC */
> +
> +#ifdef DEBUG_IOC
> +#define DPRINTF(fmt, ...) \
> +    do { fprintf(stderr, "channel-websock: " fmt, ## __VA_ARGS__); } while (0)
> +#else
> +#define DPRINTF(fmt, ...) \
> +    do { } while (0)
> +#endif
> +
> +/* Max amount to allow in rawinput/rawoutput buffers */
> +#define QIO_CHANNEL_WEBSOCK_MAX_BUFFER 8192
> +
> +#define B64LEN(__x) (((__x + 2) / 3) * 12 / 3)

Where is that magic calculation used?

> +#define SHA1_DIGEST_LEN 20
> +
> +#define QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN 24
> +#define QIO_CHANNEL_WEBSOCK_GUID "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
> +#define QIO_CHANNEL_WEBSOCK_GUID_LEN strlen(QIO_CHANNEL_WEBSOCK_GUID)
> +
> +#define QIO_CHANNEL_WEBSOCK_HANDSHAKE_RESPONSE  \
> +    "HTTP/1.1 101 Switching Protocols\r\n"      \
> +    "Upgrade: websocket\r\n"                    \
> +    "Connection: Upgrade\r\n"                   \
> +    "Sec-WebSocket-Accept: %s\r\n"              \
> +    "Sec-WebSocket-Protocol: binary\r\n"        \
> +    "\r\n"
> +#define QIO_CHANNEL_WEBSOCK_HANDSHAKE_DELIM "\r\n"
> +#define QIO_CHANNEL_WEBSOCK_HANDSHAKE_END "\r\n\r\n"
> +#define QIO_CHANNEL_WEBSOCK_SUPPORTED_VERSION "13"
> +
> +#define QIO_CHANNEL_WEBSOCK_HEAD_MIN_LEN sizeof(uint16_t)
> +#define QIO_CHANNEL_WEBSOCK_HEAD_MAX_LEN \
> +    (QIO_CHANNEL_WEBSOCK_HEAD_MIN_LEN + sizeof(uint64_t) + sizeof(uint32_t))
> +
> +typedef struct QIOChannelWebsockHeader QIOChannelWebsockHeader;
> +
> +struct QEMU_PACKED QIOChannelWebsockHeader {
> +    unsigned char b0;
> +    unsigned char b1;
> +    union {
> +        struct QEMU_PACKED {
> +            uint16_t l16;
> +            QIOChannelWebsockMask m16;
> +        } s16;
> +        struct QEMU_PACKED {
> +            uint64_t l64;
> +            QIOChannelWebsockMask m64;
> +        } s64;
> +        QIOChannelWebsockMask m;
> +    } u;
> +};
> +
> +enum {
> +    QIO_CHANNEL_WEBSOCK_OPCODE_CONTINUATION = 0x0,
> +    QIO_CHANNEL_WEBSOCK_OPCODE_TEXT_FRAME = 0x1,
> +    QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME = 0x2,
> +    QIO_CHANNEL_WEBSOCK_OPCODE_CLOSE = 0x8,
> +    QIO_CHANNEL_WEBSOCK_OPCODE_PING = 0x9,
> +    QIO_CHANNEL_WEBSOCK_OPCODE_PONG = 0xA
> +};
> +
> +static char *qio_channel_websock_handshake_entry(const char *handshake,
> +                                                 size_t handshake_len,
> +                                                 const char *name)
> +{
> +    char *begin, *end, *ret = NULL;
> +    char *line = g_strdup_printf("%s%s: ",
> +                                 QIO_CHANNEL_WEBSOCK_HANDSHAKE_DELIM,
> +                                 name);
> +    begin = g_strstr_len(handshake, handshake_len, line);
> +    if (begin != NULL) {
> +        begin += strlen(line);
> +        end = g_strstr_len(begin, handshake_len - (begin - handshake),
> +                QIO_CHANNEL_WEBSOCK_HANDSHAKE_DELIM);
> +        if (end != NULL) {
> +            ret = g_strndup(begin, end - begin);
> +        }
> +    }
> +    g_free(line);
> +    return ret;
> +}
> +
> +
> +static int qio_channel_websock_handshake_send_response(QIOChannelWebsock *ioc,
> +                                                       const char *key,
> +                                                       Error **errp)
> +{
> +    char combined_key[QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN +
> +                      QIO_CHANNEL_WEBSOCK_GUID_LEN + 1];
> +    char *accept = NULL, *response = NULL;
> +    size_t responselen;
> +
> +    g_strlcpy(combined_key, key, QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN + 1);
> +    g_strlcat(combined_key, QIO_CHANNEL_WEBSOCK_GUID,
> +              QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN +
> +              QIO_CHANNEL_WEBSOCK_GUID_LEN + 1);
> +
> +    /* hash and encode it */
> +    if (qcrypto_hash_base64(QCRYPTO_HASH_ALG_SHA1,
> +                            combined_key,
> +                            QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN +
> +                            QIO_CHANNEL_WEBSOCK_GUID_LEN,
> +                            &accept,
> +                            errp) < 0) {
> +        return -1;
> +    }
> +
> +    response = g_strdup_printf(QIO_CHANNEL_WEBSOCK_HANDSHAKE_RESPONSE, accept);
> +    responselen = strlen(response);
> +    qio_buffer_reserve(&ioc->encoutput, responselen);
> +    qio_buffer_append(&ioc->encoutput, response, responselen);
> +
> +    g_free(accept);
> +    g_free(response);
> +
> +    return 0;
> +}
> +
> +static int qio_channel_websock_handshake_process(QIOChannelWebsock *ioc,
> +                                                 const char *line,
> +                                                 size_t size,
> +                                                 Error **errp)
> +{
> +    int ret = -1;
> +    char *protocols = qio_channel_websock_handshake_entry(line, size,
> +            "Sec-WebSocket-Protocol");
> +    char *version = qio_channel_websock_handshake_entry(line, size,
> +            "Sec-WebSocket-Version");
> +    char *key = qio_channel_websock_handshake_entry(line, size,
> +            "Sec-WebSocket-Key");
> +
> +    if (!protocols) {
> +        error_setg(errp, "%s", _("Missing websocket protocol header data"));
> +        goto cleanup;
> +    }
> +
> +    if (!version) {
> +        error_setg(errp, "%s", _("Missing websocket version header data"));
> +        goto cleanup;
> +    }
> +
> +    if (!key) {
> +        error_setg(errp, "%s", _("Missing websocket key header data"));
> +        goto cleanup;
> +    }
> +
> +    if (!g_strrstr(protocols, "binary")) {
> +        error_setg(errp, _("No 'binary' protocol is supported by client '%s'"),
> +                   protocols);
> +        goto cleanup;
> +    }
> +
> +    if (!g_str_equal(version, QIO_CHANNEL_WEBSOCK_SUPPORTED_VERSION)) {
> +        error_setg(errp, _("Version '%s' is not supported by client '%s'"),
> +                   QIO_CHANNEL_WEBSOCK_SUPPORTED_VERSION, version);
> +        goto cleanup;
> +    }
> +
> +    if (strlen(key) != QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN) {
> +        error_setg(errp, _("Key length '%zu' was not as expected '%d'"),
> +                   strlen(key), QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN);
> +        goto cleanup;
> +    }
> +
> +    ret = qio_channel_websock_handshake_send_response(ioc, key, errp);
> +
> + cleanup:
> +    g_free(protocols);
> +    g_free(version);
> +    g_free(key);
> +    return ret;
> +}
> +
> +static int qio_channel_websock_handshake_read(QIOChannelWebsock *ioc,
> +                                              Error **errp)
> +{
> +    char *handshake_end;
> +    ssize_t ret;
> +    /* Typical HTTP headers from novnc are 512 bytes, so limiting
> +     * total header size to 4096 is easily enough. */
> +    size_t want = 4096 - ioc->encinput.offset;
> +    qio_buffer_reserve(&ioc->encinput, want);
> +    ret = qio_channel_read(ioc->master,
> +                           (char *)qio_buffer_end(&ioc->encinput), want, errp);
> +    if (ret < 0) {
> +        return -1;
> +    }
> +    ioc->encinput.offset += ret;
> +
> +    handshake_end = g_strstr_len((char *)ioc->encinput.buffer,
> +                                 ioc->encinput.offset,
> +                                 QIO_CHANNEL_WEBSOCK_HANDSHAKE_END);
> +    if (!handshake_end) {
> +        if (ioc->encinput.offset >= 4096) {
> +            error_setg(errp, "%s",
> +                       _("End of headers not found in first 4096 bytes"));
> +            return -1;
> +        } else {
> +            return 0;
> +        }
> +    }
> +
> +    if (qio_channel_websock_handshake_process(ioc,
> +                                              (char *)ioc->encinput.buffer,
> +                                              ioc->encinput.offset,
> +                                              errp) < 0) {
> +        return -1;
> +    }
> +
> +    qio_buffer_advance(&ioc->encinput,
> +                       handshake_end - (char *)ioc->encinput.buffer +
> +                       strlen(QIO_CHANNEL_WEBSOCK_HANDSHAKE_END));
> +    return 1;

Can you comment the return values for this function; I guess -1 is error,
1 is good, what's 0 ?

> +static gboolean qio_channel_websock_handshake_send(QIOChannel *ioc,
> +                                                   GIOCondition condition,
> +                                                   gpointer user_data)
> +{
> +    QIOTask *task = user_data;
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(
> +        qio_task_get_source(task));
> +    Error *err = NULL;
> +    ssize_t ret;
> +
> +    DPRINTF("Sending websock handshake reply %p\n", wioc);
> +    ret = qio_channel_write(wioc->master,
> +                            (char *)wioc->encoutput.buffer,
> +                            wioc->encoutput.offset,
> +                            &err);
> +
> +    if (ret < 0) {
> +        qio_task_abort(task, err);
> +        DPRINTF("Error sending websock handshake reply %p: %s\n",
> +                wioc, error_get_pretty(err));
> +        error_free(err);
> +        return FALSE;
> +    }
> +
> +    qio_buffer_advance(&wioc->encoutput, ret);
> +    if (wioc->encoutput.offset == 0) {
> +        DPRINTF("Finished sending websock handshake %p\n",
> +                wioc);
> +        qio_task_complete(task);
> +        return FALSE;
> +    }
> +    return TRUE;
> +}
> +
> +static gboolean qio_channel_websock_handshake_io(QIOChannel *ioc,
> +                                                 GIOCondition condition,
> +                                                 gpointer user_data)
> +{
> +    QIOTask *task = user_data;
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(
> +        qio_task_get_source(task));
> +    Error *err = NULL;
> +    int ret;
> +
> +    DPRINTF("Reading websock handshake request %p\n", wioc);
> +    ret = qio_channel_websock_handshake_read(wioc, &err);
> +    if (ret < 0) {
> +        DPRINTF("Error reading websock handshake %s\n",
> +                error_get_pretty(err));
> +        qio_task_abort(task, err);
> +        error_free(err);
> +        return FALSE;
> +    }
> +    if (ret == 0) {
> +        DPRINTF("Blocking on more request data\n");
> +        /* need more data still */
> +        return TRUE;
> +    }
> +
> +    DPRINTF("Websock request complete, adding watch for reply %p\n",
> +            wioc);
> +
> +    object_ref(OBJECT(task));
> +    qio_channel_add_watch(
> +        wioc->master,
> +        G_IO_OUT,
> +        qio_channel_websock_handshake_send,
> +        task,
> +        (GDestroyNotify)object_unref);
> +    return FALSE;
> +}
> +
> +
> +static void qio_channel_websock_encode(QIOChannelWebsock *ioc)
> +{
> +    size_t header_size = 0;
> +    unsigned char opcode = QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME;
> +    union {
> +        char buf[QIO_CHANNEL_WEBSOCK_HEAD_MAX_LEN];
> +        QIOChannelWebsockHeader ws;
> +    } header;
> +
> +    DPRINTF("Encoding pending raw output %zu %p\n",
> +            ioc->rawoutput.offset, ioc);
> +    if (!ioc->rawoutput.offset) {
> +        return;
> +    }
> +
> +    header.ws.b0 = 0x80 | (opcode & 0x0f);

There are quite a few magic header sizes 125, (and I think I saw
some other sizes below) - some comments on them, or constants?

> +    if (ioc->rawoutput.offset <= 125) {

Dave

> +        header.ws.b1 = (uint8_t)ioc->rawoutput.offset;
> +        header_size = 2;
> +    } else if (ioc->rawoutput.offset < 65536) {
> +        header.ws.b1 = 0x7e;
> +        header.ws.u.s16.l16 = cpu_to_be16((uint16_t)ioc->rawoutput.offset);
> +        header_size = 4;
> +    } else {
> +        header.ws.b1 = 0x7f;
> +        header.ws.u.s64.l64 = cpu_to_be64(ioc->rawoutput.offset);
> +        header_size = 10;
> +    }
> +
> +    qio_buffer_reserve(&ioc->encoutput, header_size + ioc->rawoutput.offset);
> +    qio_buffer_append(&ioc->encoutput, header.buf, header_size);
> +    qio_buffer_append(&ioc->encoutput, ioc->rawoutput.buffer,
> +                      ioc->rawoutput.offset);
> +    qio_buffer_reset(&ioc->rawoutput);
> +    DPRINTF("Have %zu bytes encoded output %p\n",
> +            ioc->encoutput.offset, ioc);
> +}
> +
> +
> +static ssize_t qio_channel_websock_decode_header(QIOChannelWebsock *ioc,
> +                                                 Error **errp)
> +{
> +    unsigned char opcode = 0, fin = 0, has_mask = 0;
> +    size_t header_size = 0;
> +    size_t payload_len;
> +    QIOChannelWebsockHeader *header =
> +        (QIOChannelWebsockHeader *)ioc->encinput.buffer;
> +
> +    if (ioc->payload_remain) {
> +        error_setg(errp,
> +                   _("Decoding header but %zu bytes of payload remain"),
> +                   ioc->payload_remain);
> +        return -1;
> +    }
> +    if (ioc->encinput.offset < QIO_CHANNEL_WEBSOCK_HEAD_MIN_LEN + 4) {
> +        /* header not complete */
> +        return QIO_CHANNEL_ERR_BLOCK;
> +    }
> +
> +    fin = (header->b0 & 0x80) >> 7;
> +    opcode = header->b0 & 0x0f;
> +    has_mask = (header->b1 & 0x80) >> 7;
> +    payload_len = header->b1 & 0x7f;
> +
> +    if (opcode == QIO_CHANNEL_WEBSOCK_OPCODE_CLOSE) {
> +        /* disconnect */
> +        return 0;
> +    }
> +
> +    /* Websocket frame sanity check:
> +     * * Websocket fragmentation is not supported.
> +     * * All  websockets frames sent by a client have to be masked.
> +     * * Only binary encoding is supported.
> +     */
> +    if (!fin) {
> +        error_setg(errp, "%s", _("websocket fragmentation is not supported"));
> +        return -1;
> +    }
> +    if (!has_mask) {
> +        error_setg(errp, "%s", _("websocket frames must be masked"));
> +        return -1;
> +    }
> +    if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME) {
> +        error_setg(errp, "%s", _("only binary websocket frames are supported"));
> +        return -1;
> +    }
> +
> +    if (payload_len < 126) {
> +        ioc->payload_remain = payload_len;
> +        header_size = 6;
> +        ioc->mask = header->u.m;
> +    } else if (payload_len == 126 && ioc->encinput.offset >= 8) {
> +        ioc->payload_remain = be16_to_cpu(header->u.s16.l16);
> +        header_size = 8;
> +        ioc->mask = header->u.s16.m16;
> +    } else if (payload_len == 127 && ioc->encinput.offset >= 14) {
> +        ioc->payload_remain = be64_to_cpu(header->u.s64.l64);
> +        header_size = 14;
> +        ioc->mask = header->u.s64.m64;
> +    } else {
> +        /* header not complete */
> +        return QIO_CHANNEL_ERR_BLOCK;
> +    }
> +
> +    qio_buffer_advance(&ioc->encinput, header_size);
> +    return 1;
> +}
> +
> +
> +static ssize_t qio_channel_websock_decode_payload(QIOChannelWebsock *ioc,
> +                                                  Error **errp)
> +{
> +    size_t i;
> +    size_t payload_len;
> +    uint32_t *payload32;
> +
> +    if (!ioc->payload_remain) {
> +        error_setg(errp, "%s",
> +                   _("Decoding payload but no bytes of payload remain"));
> +        return -1;
> +    }
> +
> +    /* If we aren't at the end of the payload, then drop
> +     * off the last bytes, so we're always multiple of 4
> +     * for purpose of unmasking, except at end of payload
> +     */
> +    if (ioc->encinput.offset < ioc->payload_remain) {
> +        payload_len = ioc->encinput.offset - (ioc->encinput.offset % 4);
> +    } else {
> +        payload_len = ioc->payload_remain;
> +    }
> +    if (payload_len == 0) {
> +        return QIO_CHANNEL_ERR_BLOCK;
> +    }
> +
> +    ioc->payload_remain -= payload_len;
> +
> +    /* unmask frame */
> +    /* process 1 frame (32 bit op) */
> +    payload32 = (uint32_t *)ioc->encinput.buffer;
> +    for (i = 0; i < payload_len / 4; i++) {
> +        payload32[i] ^= ioc->mask.u;
> +    }
> +    /* process the remaining bytes (if any) */
> +    for (i *= 4; i < payload_len; i++) {
> +        ioc->encinput.buffer[i] ^= ioc->mask.c[i % 4];
> +    }
> +
> +    qio_buffer_reserve(&ioc->rawinput, payload_len);
> +    qio_buffer_append(&ioc->rawinput, ioc->encinput.buffer, payload_len);
> +    qio_buffer_advance(&ioc->encinput, payload_len);
> +    return payload_len;
> +}
> +
> +
> +QIOChannelWebsock *
> +qio_channel_websock_new_server(QIOChannel *master)
> +{
> +    QIOChannelWebsock *wioc;
> +
> +    wioc = QIO_CHANNEL_WEBSOCK(object_new(TYPE_QIO_CHANNEL_WEBSOCK));
> +
> +    wioc->master = master;
> +    object_ref(OBJECT(master));
> +
> +    return wioc;
> +}
> +
> +void qio_channel_websock_handshake(QIOChannelWebsock *ioc,
> +                                   QIOTaskFunc func,
> +                                   gpointer opaque,
> +                                   GDestroyNotify destroy)
> +{
> +    QIOTask *task;
> +
> +    task = qio_task_new(OBJECT(ioc),
> +                        func,
> +                        opaque,
> +                        destroy);
> +
> +    DPRINTF("Adding watch on master %p for websocket %p handshake\n",
> +            ioc->master, ioc);
> +    qio_channel_add_watch(ioc->master,
> +                          G_IO_IN,
> +                          qio_channel_websock_handshake_io,
> +                          task,
> +                          NULL);
> +}
> +
> +static void qio_channel_websock_init(Object *obj G_GNUC_UNUSED)
> +{
> +}
> +
> +
> +static void qio_channel_websock_finalize(Object *obj)
> +{
> +    QIOChannelWebsock *ioc = QIO_CHANNEL_WEBSOCK(obj);
> +
> +    qio_buffer_free(&ioc->encinput);
> +    qio_buffer_free(&ioc->encoutput);
> +    qio_buffer_free(&ioc->rawinput);
> +    qio_buffer_free(&ioc->rawoutput);
> +    object_unref(OBJECT(ioc->master));
> +    if (ioc->io_tag) {
> +        g_source_remove(ioc->io_tag);
> +    }
> +    if (ioc->io_err) {
> +        error_free(ioc->io_err);
> +    }
> +}
> +
> +
> +static ssize_t qio_channel_websock_read_wire(QIOChannelWebsock *ioc,
> +                                             Error **errp)
> +{
> +    ssize_t ret;
> +
> +    DPRINTF("Have %zu bytes %p\n", ioc->encoutput.offset, ioc);
> +    if (ioc->encinput.offset < 4096) {
> +        size_t want = 4096 - ioc->encinput.offset;
> +
> +        qio_buffer_reserve(&ioc->encinput, want);
> +        ret = qio_channel_read(ioc->master,
> +                               (char *)ioc->encinput.buffer +
> +                               ioc->encinput.offset,
> +                               want,
> +                               errp);
> +        if (ret < 0) {
> +            return ret;
> +        }
> +        if (ret == 0 &&
> +            ioc->encinput.offset == 0) {
> +            DPRINTF("EOF on wire & no more enc data availabl\n");
> +            return 0;
> +        }
> +        ioc->encinput.offset += ret;
> +        DPRINTF("Now have %zu bytes enc input\n", ioc->encinput.offset);
> +    }
> +
> +    if (ioc->payload_remain == 0) {
> +        DPRINTF("Looking to decode header\n");
> +        ret = qio_channel_websock_decode_header(ioc, errp);
> +        if (ret < 0) {
> +            return ret;
> +        }
> +        if (ret == 0) {
> +            DPRINTF("EOF when decoding header\n");
> +            return 0;
> +        }
> +    }
> +    DPRINTF("Looking to decode payload %zu\n", ioc->payload_remain);
> +
> +    ret = qio_channel_websock_decode_payload(ioc, errp);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +    DPRINTF("Now have %zu bytes raw input\n", ioc->rawinput.offset);
> +    return ret;
> +}
> +
> +
> +static ssize_t qio_channel_websock_write_wire(QIOChannelWebsock *ioc,
> +                                              Error **errp)
> +{
> +    ssize_t ret;
> +    ssize_t done = 0;
> +    qio_channel_websock_encode(ioc);
> +
> +    DPRINTF("Writing %zu bytes %p\n", ioc->encoutput.offset, ioc);
> +    while (ioc->encoutput.offset > 0) {
> +        ret = qio_channel_write(ioc->master,
> +                                (char *)ioc->encoutput.buffer,
> +                                ioc->encoutput.offset,
> +                                errp);
> +        if (ret < 0) {
> +            if (ret == QIO_CHANNEL_ERR_BLOCK &&
> +                done > 0) {
> +                DPRINTF("Blocking but wrote %zu\n", done);
> +                return done;
> +            } else {
> +                DPRINTF("Error while writing %s\n",
> +                        error_get_pretty(*errp));
> +                return ret;
> +            }
> +        }
> +        qio_buffer_advance(&ioc->encoutput, ret);
> +        done += ret;
> +    }
> +    DPRINTF("Wrote %zu total\n", done);
> +    return done;
> +}
> +
> +
> +static void qio_channel_websock_flush_free(gpointer user_data)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(user_data);
> +    object_unref(OBJECT(wioc));
> +}
> +
> +static void qio_channel_websock_set_watch(QIOChannelWebsock *ioc);
> +
> +static gboolean qio_channel_websock_flush(QIOChannel *ioc,
> +                                          GIOCondition condition,
> +                                          gpointer user_data)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(user_data);
> +    ssize_t ret;
> +
> +    DPRINTF("Websock master flush %p %d\n", ioc, condition);
> +    if (condition & G_IO_OUT) {
> +        ret = qio_channel_websock_write_wire(wioc, &wioc->io_err);
> +        if (ret < 0) {
> +            goto cleanup;
> +        }
> +    }
> +
> +    if (condition & G_IO_IN) {
> +        ret = qio_channel_websock_read_wire(wioc, &wioc->io_err);
> +        if (ret < 0) {
> +            goto cleanup;
> +        }
> +        if (ret == 0) {
> +            DPRINTF("Got EOF when reading %p\n", wioc);
> +            wioc->io_eof = TRUE;
> +        }
> +    }
> +
> + cleanup:
> +    qio_channel_websock_set_watch(wioc);
> +    return FALSE;
> +}
> +
> +
> +static void qio_channel_websock_unset_watch(QIOChannelWebsock *ioc)
> +{
> +    if (ioc->io_tag) {
> +        DPRINTF("Removing old master watch %u %p\n", ioc->io_tag, ioc);
> +        g_source_remove(ioc->io_tag);
> +        ioc->io_tag = 0;
> +    }
> +}
> +
> +static void qio_channel_websock_set_watch(QIOChannelWebsock *ioc)
> +{
> +    GIOCondition cond = 0;
> +
> +    qio_channel_websock_unset_watch(ioc);
> +
> +    if (ioc->io_err) {
> +        DPRINTF("Not adding master watch due to error %p %s\n",
> +                ioc, error_get_pretty(ioc->io_err));
> +        return;
> +    }
> +
> +    if (ioc->encoutput.offset) {
> +        cond |= G_IO_OUT;
> +    }
> +    if (ioc->encinput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER &&
> +        !ioc->io_eof) {
> +        cond |= G_IO_IN;
> +    }
> +
> +    DPRINTF("Cond %d output=%zu input=%zu eof=%d\n",
> +            cond, ioc->encoutput.offset, ioc->encinput.offset, ioc->io_eof);
> +    if (cond) {
> +        object_ref(OBJECT(ioc));
> +        ioc->io_tag =
> +            qio_channel_add_watch(ioc->master,
> +                                  cond,
> +                                  qio_channel_websock_flush,
> +                                  ioc,
> +                                  qio_channel_websock_flush_free);
> +    }
> +}
> +
> +
> +static ssize_t qio_channel_websock_readv(QIOChannel *ioc,
> +                                         const struct iovec *iov,
> +                                         size_t niov,
> +                                         int **fds,
> +                                         size_t *nfds,
> +                                         Error **errp)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(ioc);
> +    size_t i;
> +    ssize_t got = 0;
> +    ssize_t ret;
> +    DPRINTF("Read ioc %p %zu %p\n", iov, niov, ioc);
> +    if (fds || nfds) {
> +        error_setg(errp, "%s",
> +                   _("Cannot receive file descriptors over websocket channel"));
> +        return -1;
> +    }
> +
> +    if (wioc->io_err) {
> +        *errp = error_copy(wioc->io_err);
> +        return -1;
> +    }
> +
> +    if (!wioc->rawinput.offset) {
> +        ret = qio_channel_websock_read_wire(QIO_CHANNEL_WEBSOCK(ioc), errp);
> +        if (ret < 0) {
> +            return ret;
> +        }
> +    }
> +
> +    for (i = 0 ; i < niov ; i++) {
> +        size_t want = iov[i].iov_len;
> +        if (want > (wioc->rawinput.offset - got)) {
> +            want = (wioc->rawinput.offset - got);
> +        }
> +
> +        memcpy(iov[i].iov_base,
> +               wioc->rawinput.buffer + got,
> +               want);
> +        got += want;
> +
> +        if (want < iov[i].iov_len) {
> +            break;
> +        }
> +    }
> +
> +    qio_buffer_advance(&wioc->rawinput, got);
> +    qio_channel_websock_set_watch(wioc);
> +    DPRINTF("Returning %zu\n", got);
> +    return got;
> +}
> +
> +
> +static ssize_t qio_channel_websock_writev(QIOChannel *ioc,
> +                                          const struct iovec *iov,
> +                                          size_t niov,
> +                                          int *fds,
> +                                          size_t nfds,
> +                                          Error **errp)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(ioc);
> +    size_t i;
> +    ssize_t done = 0;
> +    ssize_t ret;
> +
> +    if (fds || nfds) {
> +        error_setg(errp, "%s",
> +                   _("Cannot send file descriptors over websocket channel"));
> +        return -1;
> +    }
> +
> +    DPRINTF("Writev %p %zu %p err=%p\n", iov, niov, ioc, wioc->io_err);
> +    if (wioc->io_err) {
> +        *errp = error_copy(wioc->io_err);
> +        return -1;
> +    }
> +
> +    if (wioc->io_eof) {
> +        error_setg(errp, "%s", "Broken pipe");
> +        return -1;
> +    }
> +
> +    for (i = 0; i < niov; i++) {
> +        size_t want = iov[i].iov_len;
> +        if ((want + wioc->rawoutput.offset) > QIO_CHANNEL_WEBSOCK_MAX_BUFFER) {
> +            want = (QIO_CHANNEL_WEBSOCK_MAX_BUFFER - wioc->rawoutput.offset);
> +        }
> +        if (want == 0) {
> +            goto done;
> +        }
> +
> +        qio_buffer_reserve(&wioc->rawoutput, want);
> +        qio_buffer_append(&wioc->rawoutput, iov[i].iov_base, want);
> +        done += want;
> +        if (want < iov[i].iov_len) {
> +            break;
> +        }
> +    }
> +
> + done:
> +    ret = qio_channel_websock_write_wire(wioc, errp);
> +    if (ret < 0 &&
> +        ret != QIO_CHANNEL_ERR_BLOCK) {
> +        qio_channel_websock_unset_watch(wioc);
> +        return -1;
> +    }
> +
> +    qio_channel_websock_set_watch(wioc);
> +
> +    if (done == 0) {
> +        return QIO_CHANNEL_ERR_BLOCK;
> +    }
> +
> +    return done;
> +}
> +
> +static void qio_channel_websock_set_blocking(QIOChannel *ioc,
> +                                             bool enabled)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(ioc);
> +
> +    qio_channel_set_blocking(wioc->master, enabled);
> +}
> +
> +static int qio_channel_websock_close(QIOChannel *ioc,
> +                                     Error **errp)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(ioc);
> +
> +    return qio_channel_close(wioc->master, errp);
> +}
> +
> +typedef struct QIOChannelWebsockSource QIOChannelWebsockSource;
> +struct QIOChannelWebsockSource {
> +    GSource parent;
> +    QIOChannelWebsock *wioc;
> +    GIOCondition condition;
> +};
> +
> +static gboolean
> +qio_channel_websock_source_prepare(GSource *source,
> +                                   gint *timeout)
> +{
> +    QIOChannelWebsockSource *wsource = (QIOChannelWebsockSource *)source;
> +    GIOCondition cond = 0;
> +    *timeout = -1;
> +
> +    if (wsource->wioc->rawinput.offset) {
> +        cond |= G_IO_IN;
> +    }
> +    if (wsource->wioc->rawoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) {
> +        cond |= G_IO_OUT;
> +    }
> +
> +#if 0
> +    DPRINTF("Prep source %d cond %d input=%zu output=%zu\n",
> +            wsource->condition, cond,
> +            wsource->wioc->rawinput.offset,
> +            wsource->wioc->rawoutput.offset);
> +#endif
> +
> +    return cond & wsource->condition;
> +}
> +
> +static gboolean
> +qio_channel_websock_source_check(GSource *source)
> +{
> +    QIOChannelWebsockSource *wsource = (QIOChannelWebsockSource *)source;
> +    GIOCondition cond = 0;
> +
> +    if (wsource->wioc->rawinput.offset) {
> +        cond |= G_IO_IN;
> +    }
> +    if (wsource->wioc->rawoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) {
> +        cond |= G_IO_OUT;
> +    }
> +
> +    if (cond & wsource->condition) {
> +        DPRINTF("Check source %d cond %d input=%zu output=%zu\n",
> +                wsource->condition, cond,
> +                wsource->wioc->rawinput.offset,
> +                wsource->wioc->rawoutput.offset);
> +    }
> +    return cond & wsource->condition;
> +}
> +
> +static gboolean
> +qio_channel_websock_source_dispatch(GSource *source,
> +                                    GSourceFunc callback,
> +                                    gpointer user_data)
> +{
> +    QIOChannelFunc func = (QIOChannelFunc)callback;
> +    QIOChannelWebsockSource *wsource = (QIOChannelWebsockSource *)source;
> +    GIOCondition cond = 0;
> +
> +    if (wsource->wioc->rawinput.offset) {
> +        cond |= G_IO_IN;
> +    }
> +    if (wsource->wioc->rawoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) {
> +        cond |= G_IO_OUT;
> +    }
> +
> +    DPRINTF("Disp source %d cond %d input=%zu output=%zu\n",
> +            wsource->condition, cond,
> +            wsource->wioc->rawinput.offset,
> +            wsource->wioc->rawoutput.offset);
> +    return (*func)(QIO_CHANNEL(wsource->wioc),
> +                   (cond & wsource->condition),
> +                   user_data);
> +}
> +
> +static void
> +qio_channel_websock_source_finalize(GSource *source)
> +{
> +    QIOChannelWebsockSource *ssource = (QIOChannelWebsockSource *)source;
> +
> +    object_unref(OBJECT(ssource->wioc));
> +}
> +
> +GSourceFuncs qio_channel_websock_source_funcs = {
> +    qio_channel_websock_source_prepare,
> +    qio_channel_websock_source_check,
> +    qio_channel_websock_source_dispatch,
> +    qio_channel_websock_source_finalize
> +};
> +
> +static GSource *qio_channel_websock_create_watch(QIOChannel *ioc,
> +                                                 GIOCondition condition)
> +{
> +    QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(ioc);
> +    QIOChannelWebsockSource *ssource;
> +    GSource *source;
> +
> +    DPRINTF("Creating websock watch %p cond=%d\n", wioc, condition);
> +    source = g_source_new(&qio_channel_websock_source_funcs,
> +                          sizeof(QIOChannelWebsockSource));
> +    g_source_set_name(source, "QIOChannelWebsock");
> +    ssource = (QIOChannelWebsockSource *)source;
> +
> +    ssource->wioc = wioc;
> +    object_ref(OBJECT(wioc));
> +
> +    ssource->condition = condition;
> +
> +    qio_channel_websock_set_watch(wioc);
> +    return source;
> +}
> +
> +static void qio_channel_websock_class_init(ObjectClass *klass,
> +                                           void *class_data G_GNUC_UNUSED)
> +{
> +    QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
> +
> +    ioc_klass->io_writev = qio_channel_websock_writev;
> +    ioc_klass->io_readv = qio_channel_websock_readv;
> +    ioc_klass->io_set_blocking = qio_channel_websock_set_blocking;
> +    ioc_klass->io_close = qio_channel_websock_close;
> +    ioc_klass->io_create_watch = qio_channel_websock_create_watch;
> +}
> +
> +static const TypeInfo qio_channel_websock_info = {
> +    .parent = TYPE_QIO_CHANNEL,
> +    .name = TYPE_QIO_CHANNEL_WEBSOCK,
> +    .instance_size = sizeof(QIOChannelWebsock),
> +    .instance_init = qio_channel_websock_init,
> +    .instance_finalize = qio_channel_websock_finalize,
> +    .class_init = qio_channel_websock_class_init,
> +};
> +
> +static void qio_channel_websock_register_types(void)
> +{
> +    type_register_static(&qio_channel_websock_info);
> +}
> +
> +type_init(qio_channel_websock_register_types);
> -- 
> 2.4.3
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

On Mon, Sep 07, 2015 at 04:44:18PM +0100, Dr. David Alan Gilbert wrote:
> * Daniel P. Berrange (berrange@redhat.com) wrote:
> > Add a QIOChannel subclass that can run the websocket protocol over
> > the top of another QIOChannel instance. This initial implementation
> > is only capable of acting as a websockets server. There is no support
> > for acting as a websockets client yet.
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> >  include/io/channel-websock.h | 108 +++++
> >  io/Makefile.objs             |   1 +
> >  io/channel-websock.c         | 965 +++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 1074 insertions(+)
> >  create mode 100644 include/io/channel-websock.h
> >  create mode 100644 io/channel-websock.c


> > diff --git a/io/channel-websock.c b/io/channel-websock.c
> > new file mode 100644
> > index 0000000..0345b90
> > --- /dev/null
> > +++ b/io/channel-websock.c
> > @@ -0,0 +1,965 @@
> > +
> > +#include "io/channel-websock.h"
> > +#include "crypto/hash.h"
> > +
> > +#include <glib/gi18n.h>
> > +
> > +/* #define DEBUG_IOC */
> > +
> > +#ifdef DEBUG_IOC
> > +#define DPRINTF(fmt, ...) \
> > +    do { fprintf(stderr, "channel-websock: " fmt, ## __VA_ARGS__); } while (0)
> > +#else
> > +#define DPRINTF(fmt, ...) \
> > +    do { } while (0)
> > +#endif
> > +
> > +/* Max amount to allow in rawinput/rawoutput buffers */
> > +#define QIO_CHANNEL_WEBSOCK_MAX_BUFFER 8192
> > +
> > +#define B64LEN(__x) (((__x + 2) / 3) * 12 / 3)
> 
> Where is that magic calculation used?

I copied these constants from the current ui/vnc-ws.h header file
originally. In there it was referenced by another constant
WS_ACCEPT_LEN, which was itself unused. I deleted WS_ACCEPT_LEN
when I found it unused, but forgot to delete this B64LEN too.

> > +static int qio_channel_websock_handshake_read(QIOChannelWebsock *ioc,
> > +                                              Error **errp)
> > +{
> > +    char *handshake_end;
> > +    ssize_t ret;
> > +    /* Typical HTTP headers from novnc are 512 bytes, so limiting
> > +     * total header size to 4096 is easily enough. */
> > +    size_t want = 4096 - ioc->encinput.offset;
> > +    qio_buffer_reserve(&ioc->encinput, want);
> > +    ret = qio_channel_read(ioc->master,
> > +                           (char *)qio_buffer_end(&ioc->encinput), want, errp);
> > +    if (ret < 0) {
> > +        return -1;
> > +    }
> > +    ioc->encinput.offset += ret;
> > +
> > +    handshake_end = g_strstr_len((char *)ioc->encinput.buffer,
> > +                                 ioc->encinput.offset,
> > +                                 QIO_CHANNEL_WEBSOCK_HANDSHAKE_END);
> > +    if (!handshake_end) {
> > +        if (ioc->encinput.offset >= 4096) {
> > +            error_setg(errp, "%s",
> > +                       _("End of headers not found in first 4096 bytes"));
> > +            return -1;
> > +        } else {
> > +            return 0;
> > +        }
> > +    }
> > +
> > +    if (qio_channel_websock_handshake_process(ioc,
> > +                                              (char *)ioc->encinput.buffer,
> > +                                              ioc->encinput.offset,
> > +                                              errp) < 0) {
> > +        return -1;
> > +    }
> > +
> > +    qio_buffer_advance(&ioc->encinput,
> > +                       handshake_end - (char *)ioc->encinput.buffer +
> > +                       strlen(QIO_CHANNEL_WEBSOCK_HANDSHAKE_END));
> > +    return 1;
> 
> Can you comment the return values for this function; I guess -1 is error,
> 1 is good, what's 0 ?

1 means we've read the full handshake response, 0 means we need to
receive more data still.


> > +static void qio_channel_websock_encode(QIOChannelWebsock *ioc)
> > +{
> > +    size_t header_size = 0;
> > +    unsigned char opcode = QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME;
> > +    union {
> > +        char buf[QIO_CHANNEL_WEBSOCK_HEAD_MAX_LEN];
> > +        QIOChannelWebsockHeader ws;
> > +    } header;
> > +
> > +    DPRINTF("Encoding pending raw output %zu %p\n",
> > +            ioc->rawoutput.offset, ioc);
> > +    if (!ioc->rawoutput.offset) {
> > +        return;
> > +    }
> > +
> > +    header.ws.b0 = 0x80 | (opcode & 0x0f);
> 
> There are quite a few magic header sizes 125, (and I think I saw
> some other sizes below) - some comments on them, or constants?

This code was derived from ui/vnc-ws.c which is full of magic,
so I've mostly just inherited decisions made by that original
author. I'll fix up this new code to be less magic and use
constants and/or comments to clarify

> 
> > +    if (ioc->rawoutput.offset <= 125) {
> 
> Dave
> 
> > +        header.ws.b1 = (uint8_t)ioc->rawoutput.offset;
> > +        header_size = 2;
> > +    } else if (ioc->rawoutput.offset < 65536) {
> > +        header.ws.b1 = 0x7e;
> > +        header.ws.u.s16.l16 = cpu_to_be16((uint16_t)ioc->rawoutput.offset);
> > +        header_size = 4;
> > +    } else {
> > +        header.ws.b1 = 0x7f;
> > +        header.ws.u.s64.l64 = cpu_to_be64(ioc->rawoutput.offset);
> > +        header_size = 10;
> > +    }
> > +
> > +    qio_buffer_reserve(&ioc->encoutput, header_size + ioc->rawoutput.offset);
> > +    qio_buffer_append(&ioc->encoutput, header.buf, header_size);
> > +    qio_buffer_append(&ioc->encoutput, ioc->rawoutput.buffer,
> > +                      ioc->rawoutput.offset);
> > +    qio_buffer_reset(&ioc->rawoutput);
> > +    DPRINTF("Have %zu bytes encoded output %p\n",
> > +            ioc->encoutput.offset, ioc);
> > +}

Regards,
Daniel