[Spice-devel] [PATCH 4/5] server: add websockets support via libwebsockets

Christophe Fergeau cfergeau at redhat.com
Tue Oct 23 03:07:02 PDT 2012


On Fri, Oct 19, 2012 at 01:50:11PM +0200, Alon Levy wrote:
> New API: spice_server_set_ws_ports
> 
> This adds an optional dependency on libwebsockets. You need to get my
> patched 0.0.3 version here:
>  git://people.freedesktop.org/~alon/libwebsockets
> 
> There is no qemu patches yet, to test change in reds.c the default value
> of spice_ws_port to 5959 (for the default of spice-html5).
> 
> For testing there is an online client at
>  http://spice-space.org/spice-html5/spice.html
> 
> Known issues:
>  1. The tester (server/tests/test_display_no_ssl) gets into dropping all
>   data after a few seconds, I think it's an issue with the implemented
>   watches, but haven't figured it out.
> 
>  2. libwebsocket's read interface is inverted to what our code expects,
>  i.e. there is no libwebsocket_read, so there is an additional copy
>  involved (see RedsWebSocket). This can be fixed.
> 
>  3. Listening on a separate port. Since the headers are different, we
>  could listen on the same port (first three bytes RED/GET). I don't know
>  if we want to?
> 
> Todos:
>  1. SSL not implemented yet. Needs some thought as to how.
> 
>  2. Serve spice-html5 when accessed as a http server. Nice to have.
> ---
>  configure.ac                     |  15 ++
>  server/Makefile.am               |   4 +
>  server/reds-private.h            |  47 +++++-
>  server/reds.c                    |  79 ++++++----
>  server/reds.h                    |  17 +++
>  server/reds_websockets.c         | 311 +++++++++++++++++++++++++++++++++++++++
>  server/reds_websockets.h         |   9 ++
>  server/spice-server.syms         |   5 +
>  server/spice.h                   |   7 +
>  server/tests/test_display_base.c |   4 +-
>  10 files changed, 466 insertions(+), 32 deletions(-)
>  create mode 100644 server/reds_websockets.c
>  create mode 100644 server/reds_websockets.h
> 
> diff --git a/configure.ac b/configure.ac
> index dff930d..5561d2c 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -160,6 +160,13 @@ AC_ARG_ENABLE(automated_tests,
>  AS_IF([test x"$enable_automated_tests" != "xno"], [enable_automated_tests="yes"])
>  AM_CONDITIONAL(SUPPORT_AUTOMATED_TESTS, test "x$enable_automated_tests" != "xno")
>  
> +AC_ARG_ENABLE(libwebsockets,
> +[  --enable-libwebsockets    Enable websockets server support (no need for proxy)],,
> +[enable_libwebsockets="yes"])

Would be better if this defaulted to "check" and used libwebsockets if
available, and don't use it if it's not

> +AS_IF([test x"enable_libwebsockets" != "xyes"], [enable_websockets="no"])
> +if test "x$enable_libwebsockets" = "xyes"; then
> +   AC_DEFINE([USE_LIBWEBSOCKETS], [1], [Define if supporting websocket connections])
> +fi
>  
>  dnl =========================================================================
>  dnl Check deps
> @@ -237,6 +244,12 @@ if test "x$enable_smartcard" = "xyes"; then
>      SPICE_REQUIRES+=" libcacard >= 0.1.2"
>  fi
>  
> +if test "x$enable_libwebsockets" = "xyes"; then
> +    PKG_CHECK_MODULES(LIBWEBSOCKETS, libwebsockets >= 0.0.3)
> +    AC_SUBST(LIBWEBSOCKETS_LIBS)
> +    AC_SUBST(LIBWEBSOCKETS_CFLAGS)
> +    SPICE_REQUIRES+=" libwebsockets >= 0.0.3"
> +fi
>  
>  PKG_CHECK_MODULES(PIXMAN, pixman-1 >= 0.17.7)
>  AC_SUBST(PIXMAN_CFLAGS)
> @@ -536,6 +549,8 @@ echo "
>          SASL support:             ${enable_sasl}
>  
>          Automated tests:          ${enable_automated_tests}
> +
> +        libwebsockets:            ${enable_libwebsockets}
>  "
>  
>  if test $os_win32 == "yes" ; then
> diff --git a/server/Makefile.am b/server/Makefile.am
> index b62d98c..a7d56d4 100644
> --- a/server/Makefile.am
> +++ b/server/Makefile.am
> @@ -10,6 +10,7 @@ AM_CPPFLAGS =					\
>  	$(SLIRP_CFLAGS)				\
>  	$(SMARTCARD_CFLAGS)			\
>  	$(SSL_CFLAGS)				\
> +	$(LIBWEBSOCKETS_CFLAGS)		\
>  	$(VISIBILITY_HIDDEN_CFLAGS)		\
>  	$(WARN_CFLAGS)				\
>  	$(NULL)
> @@ -38,6 +39,7 @@ libspice_server_la_LIBADD =						\
>  	$(SLIRP_LIBS)							\
>  	$(SSL_LIBS)							\
>  	$(Z_LIBS)							\
> +	$(LIBWEBSOCKETS_LIBS)				\
>  	$(NULL)
>  
>  libspice_server_la_SOURCES =			\
> @@ -91,6 +93,8 @@ libspice_server_la_SOURCES =			\
>  	spicevmc.c				\
>  	zlib_encoder.c				\
>  	zlib_encoder.h				\
> +	reds_websockets.c				\
> +	reds_websockets.h				\

Compilation of this should depend on websockets being available or not


>  	$(NULL)
>  
>  if SUPPORT_TUNNEL
> diff --git a/server/reds-private.h b/server/reds-private.h
> index 3db6565..a5903b3 100644
> --- a/server/reds-private.h
> +++ b/server/reds-private.h
> @@ -4,6 +4,16 @@
>  #include <time.h>
>  
>  #include <spice/protocol.h>
> +#include <spice/stats.h>
> +
> +#if USE_LIBWEBSOCKETS
> +#include <libwebsockets.h>
> +#endif
> +
> +#include "reds.h"
> +#include "char_device.h"
> +#include "agent-msg-filter.h"
> +#include "main_channel.h"
>  
>  #define MIGRATE_TIMEOUT (1000 * 10) /* 10sec */
>  #define MM_TIMER_GRANULARITY_MS (1000 / 30)
> @@ -34,10 +44,6 @@ typedef struct VDIReadBuf {
>      uint8_t data[SPICE_AGENT_MAX_DATA_SIZE];
>  } VDIReadBuf;
>  
> -static VDIReadBuf *vdi_port_read_buf_get(void);
> -static VDIReadBuf *vdi_port_read_buf_ref(VDIReadBuf *buf);
> -static void vdi_port_read_buf_unref(VDIReadBuf *buf);
> -
>  enum {
>      VDI_PORT_READ_STATE_READ_HEADER,
>      VDI_PORT_READ_STATE_GET_BUFF,
> @@ -125,9 +131,19 @@ typedef struct RedsClientMonitorsConfig {
>      int buffer_pos;
>  } RedsClientMonitorsConfig;
>  
> +#ifdef USE_LIBWEBSOCKETS
> +#define REDS_MAX_WEBSOCKETS 32
> +#endif
> +
>  typedef struct RedsState {
>      int listen_socket;
>      int secure_listen_socket;
> +#ifdef USE_LIBWEBSOCKETS
> +	struct libwebsocket_context *ws_context;
> +    RedsWebSocket ws[REDS_MAX_WEBSOCKETS];
> +    int ws_in_service_fd;
> +    int ws_count;
> +#endif
>      SpiceWatch *listen_watch;
>      SpiceWatch *secure_listen_watch;
>      VDIPortState agent_state;
> @@ -179,4 +195,27 @@ typedef struct RedsState {
>      RedsClientMonitorsConfig client_monitors_config;
>  } RedsState;
>  
> +typedef struct AsyncRead {
> +    RedsStream *stream;
> +    void *opaque;
> +    uint8_t *now;
> +    uint8_t *end;
> +    void (*done)(void *opaque);
> +    void (*error)(void *opaque, int err);
> +} AsyncRead;
> +
> +typedef struct RedLinkInfo {
> +    RedsStream *stream;
> +    AsyncRead asyc_read;
> +    SpiceLinkHeader link_header;
> +    SpiceLinkMess *link_mess;
> +    int mess_pos;
> +    TicketInfo tiTicketing;
> +    SpiceLinkAuthMechanism auth_mechanism;
> +    int skip_auth;
> +} RedLinkInfo;
> +
> +RedLinkInfo *spice_server_add_client_create_link(SpiceServer *s, int socket, int skip_auth);
> +void reds_handle_new_link(RedLinkInfo *link);
> +
>  #endif
> diff --git a/server/reds.c b/server/reds.c
> index 98c8706..bd16764 100644
> --- a/server/reds.c
> +++ b/server/reds.c
> @@ -74,9 +74,16 @@
>  #ifdef USE_SMARTCARD
>  #include "smartcard.h"
>  #endif
> +#if USE_LIBWEBSOCKETS
> +#include "reds_websockets.h"
> +#endif
>  
>  #include "reds-private.h"
>  
> +static VDIReadBuf *vdi_port_read_buf_get(void);
> +static VDIReadBuf *vdi_port_read_buf_ref(VDIReadBuf *buf);
> +static void vdi_port_read_buf_unref(VDIReadBuf *buf);
> +
>  SpiceCoreInterface *core = NULL;
>  static SpiceCharDeviceInstance *vdagent = NULL;
>  static SpiceMigrateInstance *migration_interface = NULL;
> @@ -99,6 +106,10 @@ static TicketAuthentication taTicket;
>  
>  static int spice_port = -1;
>  static int spice_secure_port = -1;
> +#if USE_LIBWEBSOCKETS
> +static int spice_ws_port = -1;
> +static int spice_wss_port = -1;
> +#endif
>  static int spice_listen_socket_fd = -1;
>  static char spice_addr[256];
>  static int spice_family = PF_UNSPEC;
> @@ -127,26 +138,6 @@ static bool exit_on_disconnect = FALSE;
>  
>  static RedsState *reds = NULL;
>  
> -typedef struct AsyncRead {
> -    RedsStream *stream;
> -    void *opaque;
> -    uint8_t *now;
> -    uint8_t *end;
> -    void (*done)(void *opaque);
> -    void (*error)(void *opaque, int err);
> -} AsyncRead;
> -
> -typedef struct RedLinkInfo {
> -    RedsStream *stream;
> -    AsyncRead asyc_read;
> -    SpiceLinkHeader link_header;
> -    SpiceLinkMess *link_mess;
> -    int mess_pos;
> -    TicketInfo tiTicketing;
> -    SpiceLinkAuthMechanism auth_mechanism;
> -    int skip_auth;
> -} RedLinkInfo;
> -
>  typedef struct RedSSLParameters {
>      char keyfile_password[256];
>      char certs_file[256];
> @@ -2718,7 +2709,7 @@ static void reds_handle_read_header_done(void *opaque)
>      async_read_handler(0, 0, &link->asyc_read);
>  }
>  
> -static void reds_handle_new_link(RedLinkInfo *link)
> +void reds_handle_new_link(RedLinkInfo *link)
>  {
>      AsyncRead *obj = &link->asyc_read;
>      obj->opaque = link;
> @@ -2882,7 +2873,6 @@ static void reds_accept_ssl_connection(int fd, int event, void *data)
>      }
>  }
>  
> -
>  static void reds_accept(int fd, int event, void *data)
>  {
>      int socket;
> @@ -2896,25 +2886,33 @@ static void reds_accept(int fd, int event, void *data)
>          close(socket);
>  }
>  
> -
> -SPICE_GNUC_VISIBLE int spice_server_add_client(SpiceServer *s, int socket, int skip_auth)
> +RedLinkInfo *spice_server_add_client_create_link(SpiceServer *s, int socket, int skip_auth)
>  {
>      RedLinkInfo *link;
> -    RedsStream *stream;
>  
>      spice_assert(reds == s);
>      if (!(link = reds_init_client_connection(socket))) {
>          spice_warning("accept failed");
> -        return -1;
> +        return NULL;
>      }
>  
>      link->skip_auth = skip_auth;
> +    return link;
> +}
> +
> +SPICE_GNUC_VISIBLE int spice_server_add_client(SpiceServer *s, int socket, int skip_auth)
> +{
> +    RedLinkInfo *link;
> +    RedsStream *stream;
>  
> +    link = spice_server_add_client_create_link(s, socket, skip_auth);
> +    if (!link) {
> +        return -1;
> +    }
>      stream = link->stream;
>      stream->read = stream_read_cb;
>      stream->write = stream_write_cb;
>      stream->writev = stream_writev_cb;
> -
>      reds_handle_new_link(link);
>      return 0;
>  }
> @@ -3033,6 +3031,12 @@ static int reds_init_net(void)
>              return -1;
>          }
>      }
> +
> +#if USE_LIBWEBSOCKETS
> +    if (spice_ws_port != -1 || spice_wss_port != -1) {
> +        reds_init_websocket(reds, spice_addr, spice_ws_port, spice_wss_port);
> +    }
> +#endif
>      return 0;
>  }
>  
> @@ -3949,6 +3953,27 @@ SPICE_GNUC_VISIBLE int spice_server_set_port(SpiceServer *s, int port)
>      return 0;
>  }
>  
> +
> +SPICE_GNUC_VISIBLE int spice_server_set_ws_ports(SpiceServer *s, int ws_port, int wss_port)
> +{
> +#if USE_LIBWEBSOCKETS
> +    spice_assert(reds == s);
> +    if ((ws_port < 1 || ws_port > 0xffff) && (wss_port < 1 || wss_port > 0xffff)) {
> +        return -1;
> +    }
> +    if (ws_port > 0 && ws_port < 0xffff) {
> +        spice_ws_port = ws_port;
> +    }
> +    if (wss_port > 0 && wss_port < 0xffff) {
> +        spice_wss_port = wss_port;
> +    }
> +    return 0;
> +#else
> +    fprintf(stderr, "libwebsockets is unsupported in this spice build\n");
> +    return -1;
> +#endif
> +}
> +
>  SPICE_GNUC_VISIBLE void spice_server_set_addr(SpiceServer *s, const char *addr, int flags)
>  {
>      spice_assert(reds == s);
> diff --git a/server/reds.h b/server/reds.h
> index f8e8d56..0d4f933 100644
> --- a/server/reds.h
> +++ b/server/reds.h
> @@ -65,6 +65,20 @@ typedef struct RedsSASL {
>  } RedsSASL;
>  #endif
>  
> +#ifdef USE_LIBWEBSOCKETS
> +typedef struct RedsWebSocket {
> +    struct libwebsocket_context *context;
> +    struct libwebsocket *wsi;
> +    SpiceWatch *watch;
> +    int fd;
> +    unsigned events;
> +    /* buffer of available data to read, always starts at offset 0 to data_avail - 1. */
> +    unsigned char *data;
> +    unsigned data_len;
> +    unsigned data_avail;
> +} RedsWebSocket;
> +#endif
> +
>  struct RedsStream {
>      int socket;
>      SpiceWatch *watch;
> @@ -73,6 +87,9 @@ struct RedsStream {
>         receive may return data afterward. check the flag before calling receive*/
>      int shutdown;
>      SSL *ssl;
> +#ifdef USE_LIBWEBSOCKETS
> +    RedsWebSocket *ws;
> +#endif
>  
>  #if HAVE_SASL
>      RedsSASL sasl;
> diff --git a/server/reds_websockets.c b/server/reds_websockets.c
> new file mode 100644
> index 0000000..24df2e5
> --- /dev/null
> +++ b/server/reds_websockets.c
> @@ -0,0 +1,311 @@
> +#include "config.h"
> +
> +#ifdef USE_LIBWEBSOCKETS
> +#include <unistd.h>
> +#include <errno.h>
> +#include <libwebsockets.h>
> +
> +#include "spice.h"
> +#include "reds.h"
> +#include "reds-private.h"
> +#include "reds_websockets.h"
> +
> +static ssize_t stream_write_ws_cb(RedsStream *s, const void *buf, size_t size)
> +{
> +    /* TODO: better way to handle the requirement of libwebsocket, perhaps
> +     * we should make a writev version for libwebsocket. Assuming writev doesn't
> +     * cause a linearlizing copy itself. */

Yep, writev would be better

> +    ssize_t ret;
> +    unsigned char *padded_buf = spice_malloc(size + LWS_SEND_BUFFER_PRE_PADDING +
> +                                          LWS_SEND_BUFFER_POST_PADDING);
> +    spice_assert(s && s->ws);
> +    memcpy(padded_buf + LWS_SEND_BUFFER_PRE_PADDING, buf, size);
> +    ret = libwebsocket_write(s->ws->wsi, &padded_buf[LWS_SEND_BUFFER_PRE_PADDING], size,
> +                             LWS_WRITE_BINARY);
> +    free(padded_buf);
> +    return ret == 0 ? size : -1; /* XXX exact bytes required? if not this is
> +                                    good enough, else need to change
> +                                    libwebsocket */
> +}
> +
> +static void reds_websocket_append_data(RedsWebSocket *ws, unsigned char *buf,
> +                                       size_t size)
> +{
> +    if (!ws->data) {
> +        ws->data = spice_malloc(size);
> +        ws->data_len = size;
> +        ws->data_avail = 0;
> +    }
> +    if (ws->data_len < size + ws->data_avail) {
> +        ws->data_len = size + ws->data_avail;
> +        ws->data = realloc(ws->data, ws->data_len);

spice_realloc, or you need to handle realloc failures.

> +    }
> +    memcpy(ws->data + ws->data_avail, buf, size);
> +    ws->data_avail += size;
> +}
> +
> +static ssize_t reds_websocket_read_data(RedsWebSocket *ws, unsigned char *buf,
> +                                        size_t size)
> +{
> +    ssize_t ret;
> +
> +    ret = ws->data_avail > size ? size : ws->data_avail;
> +    if (ret > 0) {
> +        memcpy(buf, ws->data, ret);
> +    }
> +    if (ret > 0 && ret < ws->data_avail) {
> +        memmove(ws->data, ws->data + ret, ws->data_avail - ret);
> +    }
> +    ws->data_avail -= ret;
> +    if (ws->data_avail == 0 && ret == size) {
> +        ws->data = NULL;
> +        ws->data_len = ws->data_avail = 0;

Isn't this leaking ws->data?

> +    }
> +    return ret;
> +}
> +
> +static int reds_libwebsocket_service_fd(RedsState *s, struct pollfd *pfd)
> +{
> +    int ret;
> +    if (s->ws_in_service_fd) {
> +        return 0;
> +    }
> +    s->ws_in_service_fd = 1;
> +    ret = libwebsocket_service_fd(s->ws_context, pfd);
> +    s->ws_in_service_fd = 0;

Why do we need this ws_in_service_fd variable?

> +    if (ret != 0) {
> +        if (errno == EAGAIN) {
> +            spice_debug("libwebsocket_servide_fd EAGAIN, pfd->revents = %d",

typo: servide

Apart from these comments, this looks good (and the code is not invasive
anyway).

Christophe
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